/*
- * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2019 Apple Inc. All rights reserved.
*
- * @APPLE_LICENSE_HEADER_START@
- *
- * The contents of this file constitute Original Code as defined in and
- * are subject to the Apple Public Source License Version 1.1 (the
- * "License"). You may not use this file except in compliance with the
- * License. Please obtain a copy of the License at
- * http://www.apple.com/publicsource and read it before using this file.
- *
- * This Original Code and all software distributed under the License are
- * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
+ *
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
+ *
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
- * License for the specific language governing rights and limitations
- * under the License.
- *
- * @APPLE_LICENSE_HEADER_END@
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ *
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
/*
* Copyright (c) 1982, 1986, 1988, 1990, 1993, 1994, 1995
* SUCH DAMAGE.
*
* @(#)tcp_input.c 8.12 (Berkeley) 5/24/95
+ * $FreeBSD: src/sys/netinet/tcp_input.c,v 1.107.2.16 2001/08/22 00:59:12 silby Exp $
+ */
+/*
+ * NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce
+ * support for mandatory and extensible security protections. This notice
+ * is included in support of clause 2.2 (b) of the Apple Public License,
+ * Version 2.0.
*/
-
-#if ISFB31
-#include "opt_ipfw.h" /* for ipfw_fwd */
-#include "opt_tcpdebug.h"
-#endif
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/sysctl.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
-#include <sys/proc.h> /* for proc0 declaration */
+#include <sys/proc.h> /* for proc0 declaration */
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/syslog.h>
+#include <sys/mcache.h>
+#if !CONFIG_EMBEDDED
+#include <sys/kasl.h>
+#endif
+#include <sys/kauth.h>
+#include <kern/cpu_number.h> /* before tcp_seq.h, for tcp_random18() */
-#include <kern/cpu_number.h> /* before tcp_seq.h, for tcp_random18() */
+#include <machine/endian.h>
#include <net/if.h>
+#include <net/if_types.h>
#include <net/route.h>
+#include <net/ntstat.h>
+#include <net/content_filter.h>
+#include <net/dlil.h>
+#include <net/multi_layer_pkt_log.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
-#include <netinet/ip_icmp.h> /* for ICMP_BANDLIM */
+#include <netinet/ip_icmp.h> /* for ICMP_BANDLIM */
#include <netinet/in_var.h>
-#include <netinet/ip_var.h>
-#include <netinet/icmp_var.h> /* for ICMP_BANDLIM */
+#include <netinet/icmp_var.h> /* for ICMP_BANDLIM */
#include <netinet/in_pcb.h>
+#include <netinet/ip_var.h>
+#include <mach/sdt.h>
#if INET6
#include <netinet/ip6.h>
#include <netinet/icmp6.h>
#include <netinet6/in6_pcb.h>
#endif
#include <netinet/tcp.h>
+#include <netinet/tcp_cache.h>
#include <netinet/tcp_fsm.h>
#include <netinet/tcp_seq.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>
+#include <netinet/tcp_cc.h>
+#include <dev/random/randomdev.h>
+#include <kern/zalloc.h>
+#if INET6
+#include <netinet6/tcp6_var.h>
+#endif
#include <netinet/tcpip.h>
#if TCPDEBUG
#include <netinet/tcp_debug.h>
-#if INET6
-union {
- struct ip _tcp_si4;
- struct ip6_hdr _tcp_si6;
-} tcp_saveip;
-#else
-struct ip tcp_saveip;
-#endif /* INET6 */
+u_char tcp_saveipgen[40]; /* the size must be of max ip header, now IPv6 */
struct tcphdr tcp_savetcp;
#endif /* TCPDEBUG */
+#include <netinet/tcp_log.h>
#if IPSEC
#include <netinet6/ipsec.h>
+#if INET6
+#include <netinet6/ipsec6.h>
+#endif
#include <netkey/key.h>
#endif /*IPSEC*/
+#if CONFIG_MACF_NET || CONFIG_MACF_SOCKET
+#include <security/mac_framework.h>
+#endif /* CONFIG_MACF_NET || CONFIG_MACF_SOCKET */
+
#include <sys/kdebug.h>
+#include <netinet/lro_ext.h>
+#if MPTCP
+#include <netinet/mptcp_var.h>
+#include <netinet/mptcp.h>
+#include <netinet/mptcp_opt.h>
+#endif /* MPTCP */
+
+#include <corecrypto/ccaes.h>
-#define DBG_LAYER_BEG NETDBG_CODE(DBG_NETTCP, 0)
-#define DBG_LAYER_END NETDBG_CODE(DBG_NETTCP, 2)
+#define DBG_LAYER_BEG NETDBG_CODE(DBG_NETTCP, 0)
+#define DBG_LAYER_END NETDBG_CODE(DBG_NETTCP, 2)
#define DBG_FNC_TCP_INPUT NETDBG_CODE(DBG_NETTCP, (3 << 8))
#define DBG_FNC_TCP_NEWCONN NETDBG_CODE(DBG_NETTCP, (7 << 8))
-static int tcprexmtthresh = 3;
-tcp_seq tcp_iss;
-tcp_cc tcp_ccgen;
+#define TCP_RTT_HISTORY_EXPIRE_TIME (60 * TCP_RETRANSHZ)
+#define TCP_RECV_THROTTLE_WIN (5 * TCP_RETRANSHZ)
+#define TCP_STRETCHACK_ENABLE_PKTCNT 2000
+
+struct tcpstat tcpstat;
+
+static int log_in_vain = 0;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, log_in_vain,
+ CTLFLAG_RW | CTLFLAG_LOCKED, &log_in_vain, 0,
+ "Log all incoming TCP connections");
+
+static int blackhole = 0;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, blackhole,
+ CTLFLAG_RW | CTLFLAG_LOCKED, &blackhole, 0,
+ "Do not send RST when dropping refused connections");
+
+SYSCTL_SKMEM_TCP_INT(OID_AUTO, delayed_ack,
+ CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_delack_enabled, 3,
+ "Delay ACK to try and piggyback it onto a data packet");
+
+SYSCTL_SKMEM_TCP_INT(OID_AUTO, tcp_lq_overflow,
+ CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_lq_overflow, 1,
+ "Listen Queue Overflow");
+
+SYSCTL_SKMEM_TCP_INT(OID_AUTO, recvbg, CTLFLAG_RW | CTLFLAG_LOCKED,
+ int, tcp_recv_bg, 0, "Receive background");
+
+#if TCP_DROP_SYNFIN
+SYSCTL_SKMEM_TCP_INT(OID_AUTO, drop_synfin,
+ CTLFLAG_RW | CTLFLAG_LOCKED, static int, drop_synfin, 1,
+ "Drop TCP packets with SYN+FIN set");
+#endif
+
+SYSCTL_NODE(_net_inet_tcp, OID_AUTO, reass, CTLFLAG_RW | CTLFLAG_LOCKED, 0,
+ "TCP Segment Reassembly Queue");
+
+static int tcp_reass_overflows = 0;
+SYSCTL_INT(_net_inet_tcp_reass, OID_AUTO, overflows,
+ CTLFLAG_RD | CTLFLAG_LOCKED, &tcp_reass_overflows, 0,
+ "Global number of TCP Segment Reassembly Queue Overflows");
+
+
+SYSCTL_SKMEM_TCP_INT(OID_AUTO, slowlink_wsize, CTLFLAG_RW | CTLFLAG_LOCKED,
+ __private_extern__ int, slowlink_wsize, 8192,
+ "Maximum advertised window size for slowlink");
-struct tcpstat tcpstat;
-SYSCTL_STRUCT(_net_inet_tcp, TCPCTL_STATS, stats,
- CTLFLAG_RD, &tcpstat , tcpstat, "");
+SYSCTL_SKMEM_TCP_INT(OID_AUTO, maxseg_unacked,
+ CTLFLAG_RW | CTLFLAG_LOCKED, int, maxseg_unacked, 8,
+ "Maximum number of outstanding segments left unacked");
-int log_in_vain = 0;
-SYSCTL_INT(_net_inet_tcp, OID_AUTO, log_in_vain, CTLFLAG_RW,
- &log_in_vain, 0, "");
+SYSCTL_SKMEM_TCP_INT(OID_AUTO, rfc3465, CTLFLAG_RW | CTLFLAG_LOCKED,
+ int, tcp_do_rfc3465, 1, "");
-int tcp_delack_enabled = 1;
-SYSCTL_INT(_net_inet_tcp, OID_AUTO, delayed_ack, CTLFLAG_RW,
- &tcp_delack_enabled, 0, "");
+SYSCTL_SKMEM_TCP_INT(OID_AUTO, rfc3465_lim2,
+ CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_do_rfc3465_lim2, 1,
+ "Appropriate bytes counting w/ L=2*SMSS");
+
+int rtt_samples_per_slot = 20;
+
+int tcp_acc_iaj_high_thresh = ACC_IAJ_HIGH_THRESH;
+u_int32_t tcp_autorcvbuf_inc_shift = 3;
+SYSCTL_SKMEM_TCP_INT(OID_AUTO, recv_allowed_iaj,
+ CTLFLAG_RW | CTLFLAG_LOCKED, int, tcp_allowed_iaj, ALLOWED_IAJ,
+ "Allowed inter-packet arrival jiter");
+#if (DEVELOPMENT || DEBUG)
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, acc_iaj_high_thresh,
+ CTLFLAG_RW | CTLFLAG_LOCKED, &tcp_acc_iaj_high_thresh, 0,
+ "Used in calculating maximum accumulated IAJ");
+
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, autorcvbufincshift,
+ CTLFLAG_RW | CTLFLAG_LOCKED, &tcp_autorcvbuf_inc_shift, 0,
+ "Shift for increment in receive socket buffer size");
+#endif /* (DEVELOPMENT || DEBUG) */
+
+SYSCTL_SKMEM_TCP_INT(OID_AUTO, doautorcvbuf,
+ CTLFLAG_RW | CTLFLAG_LOCKED, u_int32_t, tcp_do_autorcvbuf, 1,
+ "Enable automatic socket buffer tuning");
+
+SYSCTL_SKMEM_TCP_INT(OID_AUTO, autorcvbufmax,
+ CTLFLAG_RW | CTLFLAG_LOCKED, u_int32_t, tcp_autorcvbuf_max, 512 * 1024,
+ "Maximum receive socket buffer size");
+
+#if CONFIG_EMBEDDED
+int sw_lro = 1;
+#else
+int sw_lro = 0;
+#endif /* !CONFIG_EMBEDDED */
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, lro, CTLFLAG_RW | CTLFLAG_LOCKED,
+ &sw_lro, 0, "Used to coalesce TCP packets");
+
+int lrodebug = 0;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, lrodbg,
+ CTLFLAG_RW | CTLFLAG_LOCKED, &lrodebug, 0,
+ "Used to debug SW LRO");
+
+int lro_start = 4;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, lro_startcnt,
+ CTLFLAG_RW | CTLFLAG_LOCKED, &lro_start, 0,
+ "Segments for starting LRO computed as power of 2");
+
+int limited_txmt = 1;
+int early_rexmt = 1;
+int sack_ackadv = 1;
+int tcp_dsack_enable = 1;
+
+#if (DEVELOPMENT || DEBUG)
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, limited_transmit,
+ CTLFLAG_RW | CTLFLAG_LOCKED, &limited_txmt, 0,
+ "Enable limited transmit");
+
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, early_rexmt,
+ CTLFLAG_RW | CTLFLAG_LOCKED, &early_rexmt, 0,
+ "Enable Early Retransmit");
+
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, sack_ackadv,
+ CTLFLAG_RW | CTLFLAG_LOCKED, &sack_ackadv, 0,
+ "Use SACK with cumulative ack advancement as a dupack");
+
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, dsack_enable,
+ CTLFLAG_RW | CTLFLAG_LOCKED, &tcp_dsack_enable, 0,
+ "use DSACK TCP option to report duplicate segments");
+
+#endif /* (DEVELOPMENT || DEBUG) */
+int tcp_disable_access_to_stats = 1;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, disable_access_to_stats,
+ CTLFLAG_RW | CTLFLAG_LOCKED, &tcp_disable_access_to_stats, 0,
+ "Disable access to tcpstat");
+
+SYSCTL_SKMEM_TCP_INT(OID_AUTO, challengeack_limit,
+ CTLFLAG_RW | CTLFLAG_LOCKED, uint32_t, tcp_challengeack_limit, 10,
+ "Maximum number of challenge ACKs per connection per second");
+
+SYSCTL_SKMEM_TCP_INT(OID_AUTO, do_rfc5961,
+ CTLFLAG_RW | CTLFLAG_LOCKED, static int, tcp_do_rfc5961, 1,
+ "Enable/Disable full RFC 5961 compliance");
+
+extern int tcp_acc_iaj_high;
+extern int tcp_acc_iaj_react_limit;
+
+int tcprexmtthresh = 3;
+
+u_int32_t tcp_now;
+struct timeval tcp_uptime; /* uptime when tcp_now was last updated */
+lck_spin_t *tcp_uptime_lock; /* Used to sychronize updates to tcp_now */
-u_long tcp_now;
struct inpcbhead tcb;
-#define tcb6 tcb /* for KAME src sync over BSD*'s */
+#define tcb6 tcb /* for KAME src sync over BSD*'s */
struct inpcbinfo tcbinfo;
-static void tcp_dooptions __P((struct tcpcb *,
- u_char *, int, struct tcphdr *, struct tcpopt *));
-static void tcp_pulloutofband __P((struct socket *,
- struct tcphdr *, struct mbuf *));
-static void tcp_xmit_timer __P((struct tcpcb *, int));
+static void tcp_dooptions(struct tcpcb *, u_char *, int, struct tcphdr *,
+ struct tcpopt *);
+static void tcp_finalize_options(struct tcpcb *, struct tcpopt *, unsigned int);
+static void tcp_pulloutofband(struct socket *,
+ struct tcphdr *, struct mbuf *, int);
+static void tcp_xmit_timer(struct tcpcb *, int, u_int32_t, tcp_seq);
+static inline unsigned int tcp_maxmtu(struct rtentry *);
+static inline int tcp_stretch_ack_enable(struct tcpcb *tp, int thflags);
+static inline void tcp_adaptive_rwtimo_check(struct tcpcb *, int);
+
+#if TRAFFIC_MGT
+static inline void update_iaj_state(struct tcpcb *tp, uint32_t tlen,
+ int reset_size);
+void compute_iaj(struct tcpcb *tp, int nlropkts, int lro_delay_factor);
+static void compute_iaj_meat(struct tcpcb *tp, uint32_t cur_iaj);
+#endif /* TRAFFIC_MGT */
+
+#if INET6
+static inline unsigned int tcp_maxmtu6(struct rtentry *);
+#endif
+
+unsigned int get_maxmtu(struct rtentry *);
+
+static void tcp_sbrcv_grow(struct tcpcb *tp, struct sockbuf *sb,
+ struct tcpopt *to, u_int32_t tlen, u_int32_t rcvbuf_max);
+void tcp_sbrcv_trim(struct tcpcb *tp, struct sockbuf *sb);
+static void tcp_sbsnd_trim(struct sockbuf *sbsnd);
+static inline void tcp_sbrcv_tstmp_check(struct tcpcb *tp);
+static inline void tcp_sbrcv_reserve(struct tcpcb *tp, struct sockbuf *sb,
+ u_int32_t newsize, u_int32_t idealsize, u_int32_t rcvbuf_max);
+static void tcp_bad_rexmt_restore_state(struct tcpcb *tp, struct tcphdr *th);
+static void tcp_compute_rtt(struct tcpcb *tp, struct tcpopt *to,
+ struct tcphdr *th);
+static void tcp_early_rexmt_check(struct tcpcb *tp, struct tcphdr *th);
+static void tcp_bad_rexmt_check(struct tcpcb *tp, struct tcphdr *th,
+ struct tcpopt *to);
+/*
+ * Constants used for resizing receive socket buffer
+ * when timestamps are not supported
+ */
+#define TCPTV_RCVNOTS_QUANTUM 100
+#define TCP_RCVNOTS_BYTELEVEL 204800
/*
- * Neighbor Discovery, Neighbor Unreachability Detection
- * Upper layer hint.
+ * Constants used for limiting early retransmits
+ * to 10 per minute.
*/
-#define ND6_HINT(tp) { \
- if ((tp) && (tp)->t_inpcb && (tp)->t_inpcb->in6p_route.ro_rt) \
- nd6_nud_hint((tp)->t_inpcb->in6p_route.ro_rt, NULL); \
+#define TCP_EARLY_REXMT_WIN (60 * TCP_RETRANSHZ) /* 60 seconds */
+#define TCP_EARLY_REXMT_LIMIT 10
+
+extern void ipfwsyslog( int level, const char *format, ...);
+extern int fw_verbose;
+
+#if IPFIREWALL
+extern void ipfw_stealth_stats_incr_tcp(void);
+
+#define log_in_vain_log( a ) { \
+ if ( (log_in_vain == 3 ) && (fw_verbose == 2)) { /* Apple logging, log to ipfw.log */ \
+ ipfwsyslog a ; \
+ } else if ( (log_in_vain == 4 ) && (fw_verbose == 2)) { \
+ ipfw_stealth_stats_incr_tcp(); \
+ } \
+ else log a ; \
}
+#else
+#define log_in_vain_log( a ) { log a; }
+#endif
+int tcp_rcvunackwin = TCPTV_UNACKWIN;
+int tcp_maxrcvidle = TCPTV_MAXRCVIDLE;
+SYSCTL_SKMEM_TCP_INT(OID_AUTO, rcvsspktcnt, CTLFLAG_RW | CTLFLAG_LOCKED,
+ int, tcp_rcvsspktcnt, TCP_RCV_SS_PKTCOUNT, "packets to be seen before receiver stretches acks");
-extern u_long current_active_connections;
-extern u_long last_active_conn_count;
+#define DELAY_ACK(tp, th) \
+ (CC_ALGO(tp)->delay_ack != NULL && CC_ALGO(tp)->delay_ack(tp, th))
-extern u_long *delack_bitmask;
+static int tcp_dropdropablreq(struct socket *head);
+static void tcp_newreno_partial_ack(struct tcpcb *tp, struct tcphdr *th);
+static void update_base_rtt(struct tcpcb *tp, uint32_t rtt);
+void tcp_set_background_cc(struct socket *so);
+void tcp_set_foreground_cc(struct socket *so);
+static void tcp_set_new_cc(struct socket *so, uint16_t cc_index);
+static void tcp_bwmeas_check(struct tcpcb *tp);
+#if TRAFFIC_MGT
+void
+reset_acc_iaj(struct tcpcb *tp)
+{
+ tp->acc_iaj = 0;
+ CLEAR_IAJ_STATE(tp);
+}
+static inline void
+update_iaj_state(struct tcpcb *tp, uint32_t size, int rst_size)
+{
+ if (rst_size > 0) {
+ tp->iaj_size = 0;
+ }
+ if (tp->iaj_size == 0 || size >= tp->iaj_size) {
+ tp->iaj_size = size;
+ tp->iaj_rcv_ts = tcp_now;
+ tp->iaj_small_pkt = 0;
+ }
+}
+/* For every 32 bit unsigned integer(v), this function will find the
+ * largest integer n such that (n*n <= v). This takes at most 16 iterations
+ * irrespective of the value of v and does not involve multiplications.
+ */
+static inline int
+isqrt(unsigned int val)
+{
+ unsigned int sqrt_cache[11] = {0, 1, 4, 9, 16, 25, 36, 49, 64, 81, 100};
+ unsigned int temp, g = 0, b = 0x8000, bshft = 15;
+ if (val <= 100) {
+ for (g = 0; g <= 10; ++g) {
+ if (sqrt_cache[g] > val) {
+ g--;
+ break;
+ } else if (sqrt_cache[g] == val) {
+ break;
+ }
+ }
+ } else {
+ do {
+ temp = (((g << 1) + b) << (bshft--));
+ if (val >= temp) {
+ g += b;
+ val -= temp;
+ }
+ b >>= 1;
+ } while (b > 0 && val > 0);
+ }
+ return g;
+}
/*
- * Insert segment ti into reassembly queue of tcp with
- * control block tp. Return TH_FIN if reassembly now includes
- * a segment with FIN. The macro form does the common case inline
- * (segment is the next to be received on an established connection,
- * and the queue is empty), avoiding linkage into and removal
- * from the queue and repetition of various conversions.
- * Set DELACK for segments received in order, but ack immediately
- * when segments are out of order (so fast retransmit can work).
+ * With LRO, roughly estimate the inter arrival time between
+ * each sub coalesced packet as an average. Count the delay
+ * cur_iaj to be the delay between the last packet received
+ * and the first packet of the LRO stream. Due to round off errors
+ * cur_iaj may be the same as lro_delay_factor. Averaging has
+ * round off errors too. lro_delay_factor may be close to 0
+ * in steady state leading to lower values fed to compute_iaj_meat.
*/
-#if INET6
-#define _ONLY_IF_INET6_(x) x
-#else
-#define _ONLY_IF_INET6_(x)
-#endif
-#define TCP_REASS(tp, th, tilen, m, so, flags, isipv6, needwakeup) { \
- if ((th)->th_seq == (tp)->rcv_nxt && \
- (tp)->segq.lh_first == NULL && \
- (tp)->t_state == TCPS_ESTABLISHED) { \
- if (tcp_delack_enabled) {\
- if (last_active_conn_count > DELACK_BITMASK_THRESH) \
- TCP_DELACK_BITSET(tp->t_inpcb->hash_element); \
- tp->t_flags |= TF_DELACK; \
- } \
- else \
- tp->t_flags |= TF_ACKNOW; \
- (tp)->rcv_nxt += (tilen); \
- flags = (th)->th_flags & TH_FIN; \
- tcpstat.tcps_rcvpack++;\
- tcpstat.tcps_rcvbyte += (tilen);\
- _ONLY_IF_INET6_(ND6_HINT(tp);) \
- sbappend(&(so)->so_rcv, (m)); \
- needwakeup++; \
- } else { \
- (flags) = tcp_reass((tp), (th), (tilen), (m), (isipv6)); \
- tp->t_flags |= TF_ACKNOW; \
- } \
+void
+compute_iaj(struct tcpcb *tp, int nlropkts, int lro_delay_factor)
+{
+ uint32_t cur_iaj = tcp_now - tp->iaj_rcv_ts;
+ uint32_t timediff = 0;
+
+ if (cur_iaj >= lro_delay_factor) {
+ cur_iaj = cur_iaj - lro_delay_factor;
+ }
+
+ compute_iaj_meat(tp, cur_iaj);
+
+ if (nlropkts <= 1) {
+ return;
+ }
+
+ nlropkts--;
+
+ timediff = lro_delay_factor / nlropkts;
+
+ while (nlropkts > 0) {
+ compute_iaj_meat(tp, timediff);
+ nlropkts--;
+ }
+}
+
+static
+void
+compute_iaj_meat(struct tcpcb *tp, uint32_t cur_iaj)
+{
+ /* When accumulated IAJ reaches MAX_ACC_IAJ in milliseconds,
+ * throttle the receive window to a minimum of MIN_IAJ_WIN packets
+ */
+#define MAX_ACC_IAJ (tcp_acc_iaj_high_thresh + tcp_acc_iaj_react_limit)
+#define IAJ_DIV_SHIFT 4
+#define IAJ_ROUNDUP_CONST (1 << (IAJ_DIV_SHIFT - 1))
+
+ uint32_t allowed_iaj, acc_iaj = 0;
+
+ uint32_t mean, temp;
+ int32_t cur_iaj_dev;
+
+ cur_iaj_dev = (cur_iaj - tp->avg_iaj);
+
+ /* Allow a jitter of "allowed_iaj" milliseconds. Some connections
+ * may have a constant jitter more than that. We detect this by
+ * using standard deviation.
+ */
+ allowed_iaj = tp->avg_iaj + tp->std_dev_iaj;
+ if (allowed_iaj < tcp_allowed_iaj) {
+ allowed_iaj = tcp_allowed_iaj;
+ }
+
+ /* Initially when the connection starts, the senders congestion
+ * window is small. During this period we avoid throttling a
+ * connection because we do not have a good starting point for
+ * allowed_iaj. IAJ_IGNORE_PKTCNT is used to quietly gloss over
+ * the first few packets.
+ */
+ if (tp->iaj_pktcnt > IAJ_IGNORE_PKTCNT) {
+ if (cur_iaj <= allowed_iaj) {
+ if (tp->acc_iaj >= 2) {
+ acc_iaj = tp->acc_iaj - 2;
+ } else {
+ acc_iaj = 0;
+ }
+ } else {
+ acc_iaj = tp->acc_iaj + (cur_iaj - allowed_iaj);
+ }
+
+ if (acc_iaj > MAX_ACC_IAJ) {
+ acc_iaj = MAX_ACC_IAJ;
+ }
+ tp->acc_iaj = acc_iaj;
+ }
+
+ /* Compute weighted average where the history has a weight of
+ * 15 out of 16 and the current value has a weight of 1 out of 16.
+ * This will make the short-term measurements have more weight.
+ *
+ * The addition of 8 will help to round-up the value
+ * instead of round-down
+ */
+ tp->avg_iaj = (((tp->avg_iaj << IAJ_DIV_SHIFT) - tp->avg_iaj)
+ + cur_iaj + IAJ_ROUNDUP_CONST) >> IAJ_DIV_SHIFT;
+
+ /* Compute Root-mean-square of deviation where mean is a weighted
+ * average as described above.
+ */
+ temp = tp->std_dev_iaj * tp->std_dev_iaj;
+ mean = (((temp << IAJ_DIV_SHIFT) - temp)
+ + (cur_iaj_dev * cur_iaj_dev)
+ + IAJ_ROUNDUP_CONST) >> IAJ_DIV_SHIFT;
+
+ tp->std_dev_iaj = isqrt(mean);
+
+ DTRACE_TCP3(iaj, struct tcpcb *, tp, uint32_t, cur_iaj,
+ uint32_t, allowed_iaj);
+
+ return;
}
+#endif /* TRAFFIC_MGT */
/*
- * Note:
- * in the ip header part of the ipqe_tcp structure only the length is used.
+ * Perform rate limit check per connection per second
+ * tp->t_challengeack_last is the last_time diff was greater than 1sec
+ * tp->t_challengeack_count is the number of ACKs sent (within 1sec)
+ * Return TRUE if we shouldn't send the ACK due to rate limitation
+ * Return FALSE if it is still ok to send challenge ACK
*/
-int
-tcp_reass(tp, th, tilen, m, isipv6)
- register struct tcpcb *tp;
- register struct tcphdr *th;
- u_int16_t tilen;
- struct mbuf *m;
-#if INET6
- int isipv6;
-#endif
+static boolean_t
+tcp_is_ack_ratelimited(struct tcpcb *tp)
{
- register struct ipqent *p, *q, *nq, *tiqe;
- struct socket *so = tp->t_inpcb->inp_socket;
- int flags;
+ boolean_t ret = TRUE;
+ uint32_t now = tcp_now;
+ int32_t diff = 0;
+
+ diff = timer_diff(now, 0, tp->t_challengeack_last, 0);
+ /* If it is first time or diff > 1000ms,
+ * update the challengeack_last and reset the
+ * current count of ACKs
+ */
+ if (tp->t_challengeack_last == 0 || diff >= 1000) {
+ tp->t_challengeack_last = now;
+ tp->t_challengeack_count = 0;
+ ret = FALSE;
+ } else if (tp->t_challengeack_count < tcp_challengeack_limit) {
+ ret = FALSE;
+ }
+
+ /* Careful about wrap-around */
+ if (ret == FALSE && (tp->t_challengeack_count + 1 > 0)) {
+ tp->t_challengeack_count++;
+ }
+
+ return ret;
+}
+
+/* Check if enough amount of data has been acknowledged since
+ * bw measurement was started
+ */
+static void
+tcp_bwmeas_check(struct tcpcb *tp)
+{
+ int32_t bw_meas_bytes;
+ uint32_t bw, bytes, elapsed_time;
+
+ if (SEQ_LEQ(tp->snd_una, tp->t_bwmeas->bw_start)) {
+ return;
+ }
+
+ bw_meas_bytes = tp->snd_una - tp->t_bwmeas->bw_start;
+ if ((tp->t_flagsext & TF_BWMEAS_INPROGRESS) &&
+ bw_meas_bytes >= (int32_t)(tp->t_bwmeas->bw_size)) {
+ bytes = bw_meas_bytes;
+ elapsed_time = tcp_now - tp->t_bwmeas->bw_ts;
+ if (elapsed_time > 0) {
+ bw = bytes / elapsed_time;
+ if (bw > 0) {
+ if (tp->t_bwmeas->bw_sndbw > 0) {
+ tp->t_bwmeas->bw_sndbw =
+ (((tp->t_bwmeas->bw_sndbw << 3)
+ - tp->t_bwmeas->bw_sndbw)
+ + bw) >> 3;
+ } else {
+ tp->t_bwmeas->bw_sndbw = bw;
+ }
+
+ /* Store the maximum value */
+ if (tp->t_bwmeas->bw_sndbw_max == 0) {
+ tp->t_bwmeas->bw_sndbw_max =
+ tp->t_bwmeas->bw_sndbw;
+ } else {
+ tp->t_bwmeas->bw_sndbw_max =
+ max(tp->t_bwmeas->bw_sndbw,
+ tp->t_bwmeas->bw_sndbw_max);
+ }
+ }
+ }
+ tp->t_flagsext &= ~(TF_BWMEAS_INPROGRESS);
+ }
+}
+
+static int
+tcp_reass(struct tcpcb *tp, struct tcphdr *th, int *tlenp, struct mbuf *m,
+ struct ifnet *ifp, int *dowakeup)
+{
+ struct tseg_qent *q;
+ struct tseg_qent *p = NULL;
+ struct tseg_qent *nq;
+ struct tseg_qent *te = NULL;
+ struct inpcb *inp = tp->t_inpcb;
+ struct socket *so = inp->inp_socket;
+ int flags = 0;
+ struct mbuf *oodata = NULL;
+ int copy_oodata = 0;
+ u_int16_t qlimit;
+ boolean_t cell = IFNET_IS_CELLULAR(ifp);
+ boolean_t wifi = (!cell && IFNET_IS_WIFI(ifp));
+ boolean_t wired = (!wifi && IFNET_IS_WIRED(ifp));
+ boolean_t dsack_set = FALSE;
/*
* Call with th==0 after become established to
* force pre-ESTABLISHED data up to user socket.
*/
- if (th == 0)
+ if (th == NULL) {
goto present;
+ }
-#if 0 /* Not using GETTCP(m) macro */
- m->m_pkthdr.header = ti;
-#endif
+ /*
+ * If the reassembly queue already has entries or if we are going
+ * to add a new one, then the connection has reached a loss state.
+ * Reset the stretch-ack algorithm at this point.
+ */
+ tcp_reset_stretch_ack(tp);
+
+#if TRAFFIC_MGT
+ if (tp->acc_iaj > 0) {
+ reset_acc_iaj(tp);
+ }
+#endif /* TRAFFIC_MGT */
/*
- * Allocate a new queue entry, before we throw away any data.
- * If we can't, just drop the packet. XXX
+ * Limit the number of segments in the reassembly queue to prevent
+ * holding on to too many segments (and thus running out of mbufs).
+ * Make sure to let the missing segment through which caused this
+ * queue. Always keep one global queue entry spare to be able to
+ * process the missing segment.
*/
- MALLOC(tiqe, struct ipqent *, sizeof (struct ipqent), M_SONAME, M_NOWAIT);
- if (tiqe == NULL) {
+ qlimit = min(max(100, so->so_rcv.sb_hiwat >> 10),
+ (TCP_AUTORCVBUF_MAX(ifp) >> 10));
+ if (th->th_seq != tp->rcv_nxt &&
+ (tp->t_reassqlen + 1) >= qlimit) {
+ tcp_reass_overflows++;
+ tcpstat.tcps_rcvmemdrop++;
+ m_freem(m);
+ *tlenp = 0;
+ return 0;
+ }
+
+ /* Allocate a new queue entry. If we can't, just drop the pkt. XXX */
+ te = (struct tseg_qent *) zalloc(tcp_reass_zone);
+ if (te == NULL) {
tcpstat.tcps_rcvmemdrop++;
m_freem(m);
- return (0);
+ return 0;
}
+ tp->t_reassqlen++;
/*
* Find a segment which begins after this one does.
*/
- for (p = NULL, q = tp->segq.lh_first; q != NULL;
- p = q, q = q->ipqe_q.le_next)
- if (SEQ_GT(q->ipqe_tcp->ti_seq, th->th_seq))
+ LIST_FOREACH(q, &tp->t_segq, tqe_q) {
+ if (SEQ_GT(q->tqe_th->th_seq, th->th_seq)) {
break;
+ }
+ p = q;
+ }
/*
* If there is a preceding segment, it may provide some of
* segment. If it provides all of our data, drop us.
*/
if (p != NULL) {
- register struct tcpiphdr *phdr = p->ipqe_tcp;
- register int i;
-
+ int i;
/* conversion to int (in i) handles seq wraparound */
- i = phdr->ti_seq + phdr->ti_len - th->th_seq;
+ i = p->tqe_th->th_seq + p->tqe_len - th->th_seq;
if (i > 0) {
- if (i >= tilen) {
+ if (TCP_DSACK_ENABLED(tp) && i > 1) {
+ /*
+ * Note duplicate data sequnce numbers
+ * to report in DSACK option
+ */
+ tp->t_dsack_lseq = th->th_seq;
+ tp->t_dsack_rseq = th->th_seq +
+ min(i, *tlenp);
+
+ /*
+ * Report only the first part of partial/
+ * non-contiguous duplicate sequence space
+ */
+ dsack_set = TRUE;
+ }
+ if (i >= *tlenp) {
tcpstat.tcps_rcvduppack++;
- tcpstat.tcps_rcvdupbyte += tilen;
+ tcpstat.tcps_rcvdupbyte += *tlenp;
+ if (nstat_collect) {
+ nstat_route_rx(inp->inp_route.ro_rt,
+ 1, *tlenp,
+ NSTAT_RX_FLAG_DUPLICATE);
+ INP_ADD_STAT(inp, cell, wifi, wired,
+ rxpackets, 1);
+ INP_ADD_STAT(inp, cell, wifi, wired,
+ rxbytes, *tlenp);
+ tp->t_stat.rxduplicatebytes += *tlenp;
+ inp_set_activity_bitmap(inp);
+ }
m_freem(m);
- FREE(tiqe, M_SONAME);
-
-#if 1 /* XXX: NetBSD just return 0 here */
+ zfree(tcp_reass_zone, te);
+ te = NULL;
+ tp->t_reassqlen--;
/*
* Try to present any queued data
* at the left window edge to the user.
* This is needed after the 3-WHS
* completes.
*/
- goto present; /* ??? */
-#endif
+ goto present;
}
m_adj(m, i);
- tilen -= i;
+ *tlenp -= i;
th->th_seq += i;
}
}
+ tp->t_rcvoopack++;
tcpstat.tcps_rcvoopack++;
- tcpstat.tcps_rcvoobyte += tilen;
+ tcpstat.tcps_rcvoobyte += *tlenp;
+ if (nstat_collect) {
+ nstat_route_rx(inp->inp_route.ro_rt, 1, *tlenp,
+ NSTAT_RX_FLAG_OUT_OF_ORDER);
+ INP_ADD_STAT(inp, cell, wifi, wired, rxpackets, 1);
+ INP_ADD_STAT(inp, cell, wifi, wired, rxbytes, *tlenp);
+ tp->t_stat.rxoutoforderbytes += *tlenp;
+ inp_set_activity_bitmap(inp);
+ }
/*
* While we overlap succeeding segments trim them or,
* if they are completely covered, dequeue them.
*/
while (q) {
- register struct tcpiphdr *qhdr = q->ipqe_tcp;
- register int i = (th->th_seq + tilen) - qhdr->ti_seq;
-
- if (i <= 0)
+ int i = (th->th_seq + *tlenp) - q->tqe_th->th_seq;
+ if (i <= 0) {
break;
- if (i < qhdr->ti_len) {
- qhdr->ti_seq += i;
- qhdr->ti_len -= i;
- m_adj(q->ipqe_m, i);
+ }
+
+ /*
+ * Report only the first part of partial/non-contiguous
+ * duplicate segment in dsack option. The variable
+ * dsack_set will be true if a previous entry has some of
+ * the duplicate sequence space.
+ */
+ if (TCP_DSACK_ENABLED(tp) && i > 1 && !dsack_set) {
+ if (tp->t_dsack_lseq == 0) {
+ tp->t_dsack_lseq = q->tqe_th->th_seq;
+ tp->t_dsack_rseq =
+ tp->t_dsack_lseq + min(i, q->tqe_len);
+ } else {
+ /*
+ * this segment overlaps data in multple
+ * entries in the reassembly queue, move
+ * the right sequence number further.
+ */
+ tp->t_dsack_rseq =
+ tp->t_dsack_rseq + min(i, q->tqe_len);
+ }
+ }
+ if (i < q->tqe_len) {
+ q->tqe_th->th_seq += i;
+ q->tqe_len -= i;
+ m_adj(q->tqe_m, i);
break;
}
- nq = q->ipqe_q.le_next;
- m_freem(q->ipqe_m);
- LIST_REMOVE(q, ipqe_q);
- FREE(q, M_SONAME);
+
+ nq = LIST_NEXT(q, tqe_q);
+ LIST_REMOVE(q, tqe_q);
+ m_freem(q->tqe_m);
+ zfree(tcp_reass_zone, q);
+ tp->t_reassqlen--;
q = nq;
}
- /* Insert the new fragment queue entry into place. */
- tiqe->ipqe_m = m;
- /*
- * There is a IP or IPv6 header in the mbuf before th
- * so there is space for an ip header (for the length field)
- */
-#define thtoti(x) \
- ((struct tcpiphdr *)(((char *)(x)) - (sizeof (struct ip))))
+ /* Insert the new segment queue entry into place. */
+ te->tqe_m = m;
+ te->tqe_th = th;
+ te->tqe_len = *tlenp;
- tiqe->ipqe_tcp = thtoti(th);
- tiqe->ipqe_tcp->ti_len = tilen;
if (p == NULL) {
- LIST_INSERT_HEAD(&tp->segq, tiqe, ipqe_q);
+ LIST_INSERT_HEAD(&tp->t_segq, te, tqe_q);
} else {
- LIST_INSERT_AFTER(p, tiqe, ipqe_q);
+ LIST_INSERT_AFTER(p, te, tqe_q);
+ }
+
+ /*
+ * New out-of-order data exists, and is pointed to by
+ * queue entry te. Set copy_oodata to 1 so out-of-order data
+ * can be copied off to sockbuf after in-order data
+ * is copied off.
+ */
+ if (!(so->so_state & SS_CANTRCVMORE)) {
+ copy_oodata = 1;
}
present:
* Present data to user, advancing rcv_nxt through
* completed sequence space.
*/
- if (!TCPS_HAVEESTABLISHED(tp->t_state))
- return (0);
- q = tp->segq.lh_first;
- if (!q || q->ipqe_tcp->ti_seq != tp->rcv_nxt)
- return (0);
-#if 0
- /*
- * XXX from INRIA for NetBSD, but should not happen because
- * TCPS_HAVEESTABLISHED(tp->t_state) should be true here.
- */
- if (tp->t_state == TCPS_SYN_RECEIVED && q->ipqe_tcp->ti_len)
- return (0);
-#endif
+ if (!TCPS_HAVEESTABLISHED(tp->t_state)) {
+ return 0;
+ }
+ q = LIST_FIRST(&tp->t_segq);
+ if (!q || q->tqe_th->th_seq != tp->rcv_nxt) {
+ /* Stop using LRO once out of order packets arrive */
+ if (tp->t_flagsext & TF_LRO_OFFLOADED) {
+ tcp_lro_remove_state(inp->inp_laddr, inp->inp_faddr,
+ th->th_dport, th->th_sport);
+ tp->t_flagsext &= ~TF_LRO_OFFLOADED;
+ }
+
+ /*
+ * continue processing if out-of-order data
+ * can be delivered
+ */
+ if (q && (so->so_flags & SOF_ENABLE_MSGS)) {
+ goto msg_unordered_delivery;
+ }
+
+ return 0;
+ }
+
+ /*
+ * If there is already another thread doing reassembly for this
+ * connection, it is better to let it finish the job --
+ * (radar 16316196)
+ */
+ if (tp->t_flagsext & TF_REASS_INPROG) {
+ return 0;
+ }
+
+ tp->t_flagsext |= TF_REASS_INPROG;
+ /* lost packet was recovered, so ooo data can be returned */
+ tcpstat.tcps_recovered_pkts++;
+
do {
- tp->rcv_nxt += q->ipqe_tcp->ti_len;
- flags = q->ipqe_tcp->ti_flags & TH_FIN;
- nq = q->ipqe_q.le_next;
- LIST_REMOVE(q, ipqe_q);
- if (so->so_state & SS_CANTRCVMORE)
- m_freem(q->ipqe_m);
- else
- sbappend(&so->so_rcv, q->ipqe_m);
- FREE(q, M_SONAME);
- q = nq;
- } while (q && q->ipqe_tcp->ti_seq == tp->rcv_nxt);
+ tp->rcv_nxt += q->tqe_len;
+ flags = q->tqe_th->th_flags & TH_FIN;
+ LIST_REMOVE(q, tqe_q);
+ if (so->so_state & SS_CANTRCVMORE) {
+ m_freem(q->tqe_m);
+ } else {
+ /*
+ * The mbuf may be freed after it has been added to the
+ * receive socket buffer so we reinitialize th to point
+ * to a safe copy of the TCP header
+ */
+ struct tcphdr saved_tcphdr = {};
+
+ so_recv_data_stat(so, q->tqe_m, 0); /* XXXX */
+ if (so->so_flags & SOF_ENABLE_MSGS) {
+ /*
+ * Append the inorder data as a message to the
+ * receive socket buffer. Also check to see if
+ * the data we are about to deliver is the same
+ * data that we wanted to pass up to the user
+ * out of order. If so, reset copy_oodata --
+ * the received data filled a gap, and
+ * is now in order!
+ */
+ if (q == te) {
+ copy_oodata = 0;
+ }
+ }
+ memcpy(&saved_tcphdr, th, sizeof(struct tcphdr));
+ if (sbappendstream_rcvdemux(so, q->tqe_m,
+ q->tqe_th->th_seq - (tp->irs + 1), 0)) {
+ *dowakeup = 1;
+ }
+ th = &saved_tcphdr;
+
+ if (tp->t_flagsext & TF_LRO_OFFLOADED) {
+ tcp_update_lro_seq(tp->rcv_nxt,
+ inp->inp_laddr, inp->inp_faddr,
+ th->th_dport, th->th_sport);
+ }
+ }
+ zfree(tcp_reass_zone, q);
+ tp->t_reassqlen--;
+ q = LIST_FIRST(&tp->t_segq);
+ } while (q && q->tqe_th->th_seq == tp->rcv_nxt);
+ tp->t_flagsext &= ~TF_REASS_INPROG;
+
#if INET6
- if (isipv6)
- ND6_HINT(tp);
+ if ((inp->inp_vflag & INP_IPV6) != 0) {
+ KERNEL_DEBUG(DBG_LAYER_BEG,
+ ((inp->inp_fport << 16) | inp->inp_lport),
+ (((inp->in6p_laddr.s6_addr16[0] & 0xffff) << 16) |
+ (inp->in6p_faddr.s6_addr16[0] & 0xffff)),
+ 0, 0, 0);
+ } else
#endif
+ {
+ KERNEL_DEBUG(DBG_LAYER_BEG,
+ ((inp->inp_fport << 16) | inp->inp_lport),
+ (((inp->inp_laddr.s_addr & 0xffff) << 16) |
+ (inp->inp_faddr.s_addr & 0xffff)),
+ 0, 0, 0);
+ }
+
+msg_unordered_delivery:
+ /* Deliver out-of-order data as a message */
+ if (te && (so->so_flags & SOF_ENABLE_MSGS) && copy_oodata && te->tqe_len) {
+ /*
+ * make a copy of the mbuf to be delivered up to
+ * the user, and add it to the sockbuf
+ */
+ oodata = m_copym(te->tqe_m, 0, M_COPYALL, M_DONTWAIT);
+ if (oodata != NULL) {
+ if (sbappendmsgstream_rcv(&so->so_rcv, oodata,
+ te->tqe_th->th_seq - (tp->irs + 1), 1)) {
+ *dowakeup = 1;
+ tcpstat.tcps_msg_unopkts++;
+ } else {
+ tcpstat.tcps_msg_unoappendfail++;
+ }
+ }
+ }
+
+ return flags;
+}
+
+/*
+ * Reduce congestion window -- used when ECN is seen or when a tail loss
+ * probe recovers the last packet.
+ */
+static void
+tcp_reduce_congestion_window(
+ struct tcpcb *tp)
+{
+ /*
+ * If the current tcp cc module has
+ * defined a hook for tasks to run
+ * before entering FR, call it
+ */
+ if (CC_ALGO(tp)->pre_fr != NULL) {
+ CC_ALGO(tp)->pre_fr(tp);
+ }
+ ENTER_FASTRECOVERY(tp);
+ if (tp->t_flags & TF_SENTFIN) {
+ tp->snd_recover = tp->snd_max - 1;
+ } else {
+ tp->snd_recover = tp->snd_max;
+ }
+ tp->t_timer[TCPT_REXMT] = 0;
+ tp->t_timer[TCPT_PTO] = 0;
+ tp->t_rtttime = 0;
+ if (tp->t_flagsext & TF_CWND_NONVALIDATED) {
+ tcp_cc_adjust_nonvalidated_cwnd(tp);
+ } else {
+ tp->snd_cwnd = tp->snd_ssthresh +
+ tp->t_maxseg * tcprexmtthresh;
+ }
+}
- KERNEL_DEBUG(DBG_LAYER_END, ((ti->ti_dport << 16) | ti->ti_sport),
- (((ti->ti_src.s_addr & 0xffff) << 16) | (ti->ti_dst.s_addr & 0xffff)),
- ti->ti_seq, ti->ti_ack, ti->ti_win);
+/*
+ * This function is called upon reception of data on a socket. It's purpose is
+ * to handle the adaptive keepalive timers that monitor whether the connection
+ * is making progress. First the adaptive read-timer, second the TFO probe-timer.
+ *
+ * The application wants to get an event if there is a stall during read.
+ * Set the initial keepalive timeout to be equal to twice RTO.
+ *
+ * If the outgoing interface is in marginal conditions, we need to
+ * enable read probes for that too.
+ */
+static inline void
+tcp_adaptive_rwtimo_check(struct tcpcb *tp, int tlen)
+{
+ struct ifnet *outifp = tp->t_inpcb->inp_last_outifp;
+
+ if ((tp->t_adaptive_rtimo > 0 ||
+ (outifp != NULL &&
+ (outifp->if_eflags & IFEF_PROBE_CONNECTIVITY)))
+ && tlen > 0 &&
+ tp->t_state == TCPS_ESTABLISHED) {
+ tp->t_timer[TCPT_KEEP] = OFFSET_FROM_START(tp,
+ (TCP_REXMTVAL(tp) << 1));
+ tp->t_flagsext |= TF_DETECT_READSTALL;
+ tp->t_rtimo_probes = 0;
+ }
+}
- sorwakeup(so);
- return (flags);
+inline void
+tcp_keepalive_reset(struct tcpcb *tp)
+{
+ tp->t_timer[TCPT_KEEP] = OFFSET_FROM_START(tp,
+ TCP_CONN_KEEPIDLE(tp));
+ tp->t_flagsext &= ~(TF_DETECT_READSTALL);
+ tp->t_rtimo_probes = 0;
}
/*
*/
#if INET6
int
-tcp6_input(mp, offp, proto)
- struct mbuf **mp;
- int *offp, proto;
+tcp6_input(struct mbuf **mp, int *offp, int proto)
{
- tcp_input(*mp, *offp);
+#pragma unused(proto)
+ struct mbuf *m = *mp;
+ uint32_t ia6_flags;
+ struct ifnet *ifp = m->m_pkthdr.rcvif;
+
+ IP6_EXTHDR_CHECK(m, *offp, sizeof(struct tcphdr), return IPPROTO_DONE);
+
+ /* Expect 32-bit aligned data pointer on strict-align platforms */
+ MBUF_STRICT_DATA_ALIGNMENT_CHECK_32(m);
+
+ /*
+ * draft-itojun-ipv6-tcp-to-anycast
+ * better place to put this in?
+ */
+ if (ip6_getdstifaddr_info(m, NULL, &ia6_flags) == 0) {
+ if (ia6_flags & IN6_IFF_ANYCAST) {
+ struct ip6_hdr *ip6;
+
+ ip6 = mtod(m, struct ip6_hdr *);
+ icmp6_error(m, ICMP6_DST_UNREACH,
+ ICMP6_DST_UNREACH_ADDR,
+ (caddr_t)&ip6->ip6_dst - (caddr_t)ip6);
+
+ IF_TCP_STATINC(ifp, icmp6unreach);
+
+ return IPPROTO_DONE;
+ }
+ }
+
+ tcp_input(m, *offp);
return IPPROTO_DONE;
}
#endif
-void
-tcp_input(m, off)
- struct mbuf *m;
- int off;
+/* Depending on the usage of mbuf space in the system, this function
+ * will return true or false. This is used to determine if a socket
+ * buffer can take more memory from the system for auto-tuning or not.
+ */
+u_int8_t
+tcp_cansbgrow(struct sockbuf *sb)
{
- register struct tcphdr *th;
- register struct ip *ip = NULL;
- register struct ipovly *ipov;
- register struct inpcb *inp;
- u_char *optp = NULL;
- int optlen = 0;
- int len, toff;
- int hdroptlen;
- u_int16_t tilen;
- register struct tcpcb *tp = 0;
- register int thflags;
- struct socket *so = 0;
- int todrop, acked, ourfinisacked, needoutput = 0;
- struct in_addr laddr;
-#if 0
- struct in6_addr laddr6;
-#endif
- int dropsocket = 0;
- int iss = 0;
- u_long tiwin;
- struct tcpopt to; /* options in this segment */
- struct rmxp_tao *taop; /* pointer to our TAO cache entry */
- struct rmxp_tao tao_noncached; /* in case there's no cached entry */
- int need_sowwakeup = 0;
- int need_sorwakeup = 0;
-#if TCPDEBUG
- short ostate = 0;
-#endif
-#if INET6
- struct ip6_hdr *ip6 = NULL;
- int lgminh;
-#else /* INET6 */
-#define lgminh (sizeof (struct tcpiphdr))
-#endif /* INET6 */
- int isipv6 = (mtod(m, struct ip *)->ip_v == 6) ? 1 : 0;
+ /* Calculate the host level space limit in terms of MSIZE buffers.
+ * We can use a maximum of half of the available mbuf space for
+ * socket buffers.
+ */
+ u_int32_t mblim = ((nmbclusters >> 1) << (MCLSHIFT - MSIZESHIFT));
- struct proc *proc0=current_proc();
+ /* Calculate per sb limit in terms of bytes. We optimize this limit
+ * for upto 16 socket buffers.
+ */
- KERNEL_DEBUG(DBG_FNC_TCP_INPUT | DBG_FUNC_START,0,0,0,0,0);
+ u_int32_t sbspacelim = ((nmbclusters >> 4) << MCLSHIFT);
- bzero((char *)&to, sizeof(to));
+ if ((total_sbmb_cnt < mblim) &&
+ (sb->sb_hiwat < sbspacelim)) {
+ return 1;
+ } else {
+ OSIncrementAtomic64(&sbmb_limreached);
+ }
+ return 0;
+}
- tcpstat.tcps_rcvtotal++;
- /*
- * Get IP and TCP header together in first mbuf.
- * Note: IP leaves IP header in first mbuf.
+static void
+tcp_sbrcv_reserve(struct tcpcb *tp, struct sockbuf *sbrcv,
+ u_int32_t newsize, u_int32_t idealsize, u_int32_t rcvbuf_max)
+{
+ /* newsize should not exceed max */
+ newsize = min(newsize, rcvbuf_max);
+
+ /* The receive window scale negotiated at the
+ * beginning of the connection will also set a
+ * limit on the socket buffer size
*/
- th = mtod(m, struct tcpiphdr *);
+ newsize = min(newsize, TCP_MAXWIN << tp->rcv_scale);
- KERNEL_DEBUG(DBG_LAYER_BEG, ((ti->ti_dport << 16) | ti->ti_sport),
- (((ti->ti_src.s_addr & 0xffff) << 16) | (ti->ti_dst.s_addr & 0xffff)),
- ti->ti_seq, ti->ti_ack, ti->ti_win);
+ /* Set new socket buffer size */
+ if (newsize > sbrcv->sb_hiwat &&
+ (sbreserve(sbrcv, newsize) == 1)) {
+ sbrcv->sb_idealsize = min(max(sbrcv->sb_idealsize,
+ (idealsize != 0) ? idealsize : newsize), rcvbuf_max);
-#if INET6
- if (isipv6) {
- ip6 = mtod(m, struct ip6_hdr *);
- lgminh = sizeof(struct tcpip6hdr);
- } else {
- lgminh = sizeof(struct tcpiphdr);
-#endif /* INET6 */
- ip = mtod(m, struct ip *);
- ipov = (struct ipovly *)ip;
-#if INET6
+ /* Again check the limit set by the advertised
+ * window scale
+ */
+ sbrcv->sb_idealsize = min(sbrcv->sb_idealsize,
+ TCP_MAXWIN << tp->rcv_scale);
}
-#endif /* INET6 */
+}
-#if INET6
- /* XXX not a good place to put this into... */
- if (isipv6 &&
- m && (m->m_flags & M_ANYCAST6)) {
- icmp6_error(m, ICMP6_DST_UNREACH, ICMP6_DST_UNREACH_ADDR,
- (caddr_t)&ip6->ip6_dst - (caddr_t)ip6);
- return;
+/*
+ * This function is used to grow a receive socket buffer. It
+ * will take into account system-level memory usage and the
+ * bandwidth available on the link to make a decision.
+ */
+static void
+tcp_sbrcv_grow(struct tcpcb *tp, struct sockbuf *sbrcv,
+ struct tcpopt *to, u_int32_t pktlen, u_int32_t rcvbuf_max)
+{
+ struct socket *so = sbrcv->sb_so;
+
+ /*
+ * Do not grow the receive socket buffer if
+ * - auto resizing is disabled, globally or on this socket
+ * - the high water mark already reached the maximum
+ * - the stream is in background and receive side is being
+ * throttled
+ * - if there are segments in reassembly queue indicating loss,
+ * do not need to increase recv window during recovery as more
+ * data is not going to be sent. A duplicate ack sent during
+ * recovery should not change the receive window
+ */
+ if (tcp_do_autorcvbuf == 0 ||
+ (sbrcv->sb_flags & SB_AUTOSIZE) == 0 ||
+ tcp_cansbgrow(sbrcv) == 0 ||
+ sbrcv->sb_hiwat >= rcvbuf_max ||
+ (tp->t_flagsext & TF_RECV_THROTTLE) ||
+ (so->so_flags1 & SOF1_EXTEND_BK_IDLE_WANTED) ||
+ !LIST_EMPTY(&tp->t_segq)) {
+ /* Can not resize the socket buffer, just return */
+ goto out;
}
-#endif /* INET6 */
-#if INET6
- if (isipv6) {
- IP6_EXTHDR_CHECK(m, off, sizeof(struct tcphdr), );
- ip6 = mtod(m, struct ip6_hdr *);
- tilen = ntohs(ip6->ip6_plen) - off + sizeof(*ip6);
+ if (TSTMP_GT(tcp_now,
+ tp->rfbuf_ts + TCPTV_RCVBUFIDLE)) {
+ /* If there has been an idle period in the
+ * connection, just restart the measurement
+ */
+ goto out;
+ }
- if (in6_cksum(m, IPPROTO_TCP, off, tilen)) {
- tcpstat.tcps_rcvbadsum++;
- goto drop;
- }
- th = (struct tcphdr *)((caddr_t)ip6 + off);
- } else
-#endif /* INET6 */
- {
+ if (!TSTMP_SUPPORTED(tp)) {
/*
- * Get IP and TCP header together in first mbuf.
- * Note: IP leaves IP header in first mbuf.
+ * Timestamp option is not supported on this connection.
+ * If the connection reached a state to indicate that
+ * the receive socket buffer needs to grow, increase
+ * the high water mark.
*/
- /* XXX: should we still require this for IPv4? */
- if (off > sizeof (struct ip)) {
- ip_stripoptions(m, (struct mbuf *)0);
- off = sizeof(struct ip);
+ if (TSTMP_GEQ(tcp_now,
+ tp->rfbuf_ts + TCPTV_RCVNOTS_QUANTUM)) {
+ if (tp->rfbuf_cnt + pktlen >= TCP_RCVNOTS_BYTELEVEL) {
+ tcp_sbrcv_reserve(tp, sbrcv,
+ tcp_autorcvbuf_max, 0,
+ tcp_autorcvbuf_max);
+ }
+ goto out;
+ } else {
+ tp->rfbuf_cnt += pktlen;
+ return;
}
- if (m->m_len < lgminh) {
- if ((m = m_pullup(m, lgminh)) == 0) {
- tcpstat.tcps_rcvshort++;
- return;
+ } else if (to->to_tsecr != 0) {
+ /*
+ * If the timestamp shows that one RTT has
+ * completed, we can stop counting the
+ * bytes. Here we consider increasing
+ * the socket buffer if the bandwidth measured in
+ * last rtt, is more than half of sb_hiwat, this will
+ * help to scale the buffer according to the bandwidth
+ * on the link.
+ */
+ if (TSTMP_GEQ(to->to_tsecr, tp->rfbuf_ts)) {
+ if (tp->rfbuf_cnt + pktlen > (sbrcv->sb_hiwat -
+ (sbrcv->sb_hiwat >> 1))) {
+ tp->rfbuf_cnt += pktlen;
+ int32_t rcvbuf_inc, min_incr;
+ /*
+ * Increment the receive window by a
+ * multiple of maximum sized segments.
+ * This will prevent a connection from
+ * sending smaller segments on wire if it
+ * is limited by the receive window.
+ *
+ * Set the ideal size based on current
+ * bandwidth measurements. We set the
+ * ideal size on receive socket buffer to
+ * be twice the bandwidth delay product.
+ */
+ rcvbuf_inc = (tp->rfbuf_cnt << 1)
+ - sbrcv->sb_hiwat;
+
+ /*
+ * Make the increment equal to 8 segments
+ * at least
+ */
+ min_incr = tp->t_maxseg << tcp_autorcvbuf_inc_shift;
+ if (rcvbuf_inc < min_incr) {
+ rcvbuf_inc = min_incr;
+ }
+
+ rcvbuf_inc =
+ (rcvbuf_inc / tp->t_maxseg) * tp->t_maxseg;
+ tcp_sbrcv_reserve(tp, sbrcv,
+ sbrcv->sb_hiwat + rcvbuf_inc,
+ (tp->rfbuf_cnt << 1), rcvbuf_max);
}
+ /* Measure instantaneous receive bandwidth */
+ if (tp->t_bwmeas != NULL && tp->rfbuf_cnt > 0 &&
+ TSTMP_GT(tcp_now, tp->rfbuf_ts)) {
+ u_int32_t rcv_bw;
+ rcv_bw = tp->rfbuf_cnt /
+ (int)(tcp_now - tp->rfbuf_ts);
+ if (tp->t_bwmeas->bw_rcvbw_max == 0) {
+ tp->t_bwmeas->bw_rcvbw_max = rcv_bw;
+ } else {
+ tp->t_bwmeas->bw_rcvbw_max = max(
+ tp->t_bwmeas->bw_rcvbw_max, rcv_bw);
+ }
+ }
+ goto out;
+ } else {
+ tp->rfbuf_cnt += pktlen;
+ return;
}
- ip = mtod(m, struct ip *);
- ipov = (struct ipovly *)ip;
+ }
+out:
+ /* Restart the measurement */
+ tp->rfbuf_ts = 0;
+ tp->rfbuf_cnt = 0;
+ return;
+}
- /*
- * Checksum extended TCP header and data.
- */
- tilen = ip->ip_len;
- len = sizeof (struct ip) + tilen;
- bzero(ipov->ih_x1, sizeof(ipov->ih_x1));
- ipov->ih_len = (u_short)tilen;
- HTONS(ipov->ih_len);
- th = (struct tcphdr *)((caddr_t)ip + off);
- th->th_sum = in_cksum(m, len);
- if (th->th_sum) {
- tcpstat.tcps_rcvbadsum++;
- goto drop;
+/* This function will trim the excess space added to the socket buffer
+ * to help a slow-reading app. The ideal-size of a socket buffer depends
+ * on the link bandwidth or it is set by an application and we aim to
+ * reach that size.
+ */
+void
+tcp_sbrcv_trim(struct tcpcb *tp, struct sockbuf *sbrcv)
+{
+ if (tcp_do_autorcvbuf == 1 && sbrcv->sb_idealsize > 0 &&
+ sbrcv->sb_hiwat > sbrcv->sb_idealsize) {
+ int32_t trim;
+ /* compute the difference between ideal and current sizes */
+ u_int32_t diff = sbrcv->sb_hiwat - sbrcv->sb_idealsize;
+
+ /* Compute the maximum advertised window for
+ * this connection.
+ */
+ u_int32_t advwin = tp->rcv_adv - tp->rcv_nxt;
+
+ /* How much can we trim the receive socket buffer?
+ * 1. it can not be trimmed beyond the max rcv win advertised
+ * 2. if possible, leave 1/16 of bandwidth*delay to
+ * avoid closing the win completely
+ */
+ u_int32_t leave = max(advwin, (sbrcv->sb_idealsize >> 4));
+
+ /* Sometimes leave can be zero, in that case leave at least
+ * a few segments worth of space.
+ */
+ if (leave == 0) {
+ leave = tp->t_maxseg << tcp_autorcvbuf_inc_shift;
+ }
+
+ trim = sbrcv->sb_hiwat - (sbrcv->sb_cc + leave);
+ trim = imin(trim, (int32_t)diff);
+
+ if (trim > 0) {
+ sbreserve(sbrcv, (sbrcv->sb_hiwat - trim));
+ }
+ }
+}
+
+/* We may need to trim the send socket buffer size for two reasons:
+ * 1. if the rtt seen on the connection is climbing up, we do not
+ * want to fill the buffers any more.
+ * 2. if the congestion win on the socket backed off, there is no need
+ * to hold more mbufs for that connection than what the cwnd will allow.
+ */
+void
+tcp_sbsnd_trim(struct sockbuf *sbsnd)
+{
+ if (tcp_do_autosendbuf == 1 &&
+ ((sbsnd->sb_flags & (SB_AUTOSIZE | SB_TRIM)) ==
+ (SB_AUTOSIZE | SB_TRIM)) &&
+ (sbsnd->sb_idealsize > 0) &&
+ (sbsnd->sb_hiwat > sbsnd->sb_idealsize)) {
+ u_int32_t trim = 0;
+ if (sbsnd->sb_cc <= sbsnd->sb_idealsize) {
+ trim = sbsnd->sb_hiwat - sbsnd->sb_idealsize;
+ } else {
+ trim = sbsnd->sb_hiwat - sbsnd->sb_cc;
}
+ sbreserve(sbsnd, (sbsnd->sb_hiwat - trim));
+ }
+ if (sbsnd->sb_hiwat <= sbsnd->sb_idealsize) {
+ sbsnd->sb_flags &= ~(SB_TRIM);
+ }
+}
+
+/*
+ * If timestamp option was not negotiated on this connection
+ * and this connection is on the receiving side of a stream
+ * then we can not measure the delay on the link accurately.
+ * Instead of enabling automatic receive socket buffer
+ * resizing, just give more space to the receive socket buffer.
+ */
+static inline void
+tcp_sbrcv_tstmp_check(struct tcpcb *tp)
+{
+ struct socket *so = tp->t_inpcb->inp_socket;
+ u_int32_t newsize = 2 * tcp_recvspace;
+ struct sockbuf *sbrcv = &so->so_rcv;
+
+ if ((tp->t_flags & (TF_REQ_TSTMP | TF_RCVD_TSTMP)) !=
+ (TF_REQ_TSTMP | TF_RCVD_TSTMP) &&
+ (sbrcv->sb_flags & SB_AUTOSIZE) != 0) {
+ tcp_sbrcv_reserve(tp, sbrcv, newsize, 0, newsize);
+ }
+}
+
+/* A receiver will evaluate the flow of packets on a connection
+ * to see if it can reduce ack traffic. The receiver will start
+ * stretching acks if all of the following conditions are met:
+ * 1. tcp_delack_enabled is set to 3
+ * 2. If the bytes received in the last 100ms is greater than a threshold
+ * defined by maxseg_unacked
+ * 3. If the connection has not been idle for tcp_maxrcvidle period.
+ * 4. If the connection has seen enough packets to let the slow-start
+ * finish after connection establishment or after some packet loss.
+ *
+ * The receiver will stop stretching acks if there is congestion/reordering
+ * as indicated by packets on reassembly queue or an ECN. If the delayed-ack
+ * timer fires while stretching acks, it means that the packet flow has gone
+ * below the threshold defined by maxseg_unacked and the receiver will stop
+ * stretching acks. The receiver gets no indication when slow-start is completed
+ * or when the connection reaches an idle state. That is why we use
+ * tcp_rcvsspktcnt to cover slow-start and tcp_maxrcvidle to identify idle
+ * state.
+ */
+static inline int
+tcp_stretch_ack_enable(struct tcpcb *tp, int thflags)
+{
+ if (tp->rcv_by_unackwin >= (maxseg_unacked * tp->t_maxseg) &&
+ TSTMP_GEQ(tp->rcv_unackwin, tcp_now)) {
+ tp->t_flags |= TF_STREAMING_ON;
+ } else {
+ tp->t_flags &= ~TF_STREAMING_ON;
+ }
+
+ /* If there has been an idle time, reset streaming detection */
+ if (TSTMP_GT(tcp_now, tp->rcv_unackwin + tcp_maxrcvidle)) {
+ tp->t_flags &= ~TF_STREAMING_ON;
}
/*
- * Check that TCP offset makes sense,
- * pull out TCP options and adjust length. XXX
+ * If there are flags other than TH_ACK set, reset streaming
+ * detection
*/
- toff = th->th_off << 2;
- if (toff < sizeof (struct tcphdr) || toff > tilen) {
- tcpstat.tcps_rcvbadoff++;
- goto drop;
+ if (thflags & ~TH_ACK) {
+ tp->t_flags &= ~TF_STREAMING_ON;
}
- tilen -= toff;
- if (toff > sizeof (struct tcphdr)) {
-#if INET6
- if (isipv6) {
- IP6_EXTHDR_CHECK(m, off, toff, );
- ip6 = mtod(m, struct ip6_hdr *);
- th = (struct tcphdr *)((caddr_t)ip6 + off);
- } else
-#endif /* INET6 */
- {
- if (m->m_len < sizeof(struct ip) + toff) {
- if ((m = m_pullup(m, sizeof (struct ip) + toff)) == 0) {
- tcpstat.tcps_rcvshort++;
- return;
- }
- ip = mtod(m, struct ip *);
- ipov = (struct ipovly *)ip;
- th = (struct tcphdr *)((caddr_t)ip + off);
+
+ if (tp->t_flagsext & TF_DISABLE_STRETCHACK) {
+ if (tp->rcv_nostrack_pkts >= TCP_STRETCHACK_ENABLE_PKTCNT) {
+ tp->t_flagsext &= ~TF_DISABLE_STRETCHACK;
+ tp->rcv_nostrack_pkts = 0;
+ tp->rcv_nostrack_ts = 0;
+ } else {
+ tp->rcv_nostrack_pkts++;
+ }
+ }
+
+ if (!(tp->t_flagsext & (TF_NOSTRETCHACK | TF_DISABLE_STRETCHACK)) &&
+ (tp->t_flags & TF_STREAMING_ON) &&
+ (!(tp->t_flagsext & TF_RCVUNACK_WAITSS) ||
+ (tp->rcv_waitforss >= tcp_rcvsspktcnt))) {
+ return 1;
+ }
+
+ return 0;
+}
+
+/*
+ * Reset the state related to stretch-ack algorithm. This will make
+ * the receiver generate an ack every other packet. The receiver
+ * will start re-evaluating the rate at which packets come to decide
+ * if it can benefit by lowering the ack traffic.
+ */
+void
+tcp_reset_stretch_ack(struct tcpcb *tp)
+{
+ tp->t_flags &= ~(TF_STRETCHACK | TF_STREAMING_ON);
+ tp->rcv_by_unackwin = 0;
+ tp->rcv_by_unackhalfwin = 0;
+ tp->rcv_unackwin = tcp_now + tcp_rcvunackwin;
+
+ /*
+ * When there is packet loss or packet re-ordering or CWR due to
+ * ECN, the sender's congestion window is reduced. In these states,
+ * generate an ack for every other packet for some time to allow
+ * the sender's congestion window to grow.
+ */
+ tp->t_flagsext |= TF_RCVUNACK_WAITSS;
+ tp->rcv_waitforss = 0;
+}
+
+/*
+ * The last packet was a retransmission, check if this ack
+ * indicates that the retransmission was spurious.
+ *
+ * If the connection supports timestamps, we could use it to
+ * detect if the last retransmit was not needed. Otherwise,
+ * we check if the ACK arrived within RTT/2 window, then it
+ * was a mistake to do the retransmit in the first place.
+ *
+ * This function will return 1 if it is a spurious retransmit,
+ * 0 otherwise.
+ */
+int
+tcp_detect_bad_rexmt(struct tcpcb *tp, struct tcphdr *th,
+ struct tcpopt *to, u_int32_t rxtime)
+{
+ int32_t tdiff, bad_rexmt_win;
+ bad_rexmt_win = (tp->t_srtt >> (TCP_RTT_SHIFT + 1));
+
+ /* If the ack has ECN CE bit, then cwnd has to be adjusted */
+ if (TCP_ECN_ENABLED(tp) && (th->th_flags & TH_ECE)) {
+ return 0;
+ }
+ if (TSTMP_SUPPORTED(tp)) {
+ if (rxtime > 0 && (to->to_flags & TOF_TS)
+ && to->to_tsecr != 0
+ && TSTMP_LT(to->to_tsecr, rxtime)) {
+ return 1;
+ }
+ } else {
+ if ((tp->t_rxtshift == 1
+ || (tp->t_flagsext & TF_SENT_TLPROBE))
+ && rxtime > 0) {
+ tdiff = (int32_t)(tcp_now - rxtime);
+ if (tdiff < bad_rexmt_win) {
+ return 1;
}
}
- optlen = toff - sizeof (struct tcphdr);
- optp = (u_char *)(th + 1);
- /*
- * Do quick retrieval of timestamp options ("options
- * prediction?"). If timestamp is the only option and it's
- * formatted as recommended in RFC 1323 appendix A, we
- * quickly get the values now and not bother calling
- * tcp_dooptions(), etc.
+ }
+ return 0;
+}
+
+
+/*
+ * Restore congestion window state if a spurious timeout
+ * was detected.
+ */
+static void
+tcp_bad_rexmt_restore_state(struct tcpcb *tp, struct tcphdr *th)
+{
+ if (TSTMP_SUPPORTED(tp)) {
+ u_int32_t fsize, acked;
+ fsize = tp->snd_max - th->th_ack;
+ acked = BYTES_ACKED(th, tp);
+
+ /*
+ * Implement bad retransmit recovery as
+ * described in RFC 4015.
*/
- if ((optlen == TCPOLEN_TSTAMP_APPA ||
- (optlen > TCPOLEN_TSTAMP_APPA &&
- optp[TCPOLEN_TSTAMP_APPA] == TCPOPT_EOL)) &&
- *(u_int32_t *)optp == htonl(TCPOPT_TSTAMP_HDR) &&
- (th->th_flags & TH_SYN) == 0) {
- to.to_flag |= TOF_TS;
- to.to_tsval = ntohl(*(u_int32_t *)(optp + 4));
- to.to_tsecr = ntohl(*(u_int32_t *)(optp + 8));
- optp = NULL; /* we've parsed the options */
+ tp->snd_ssthresh = tp->snd_ssthresh_prev;
+
+ /* Initialize cwnd to the initial window */
+ if (CC_ALGO(tp)->cwnd_init != NULL) {
+ CC_ALGO(tp)->cwnd_init(tp);
+ }
+
+ tp->snd_cwnd = fsize + min(acked, tp->snd_cwnd);
+ } else {
+ tp->snd_cwnd = tp->snd_cwnd_prev;
+ tp->snd_ssthresh = tp->snd_ssthresh_prev;
+ if (tp->t_flags & TF_WASFRECOVERY) {
+ ENTER_FASTRECOVERY(tp);
}
+
+ /* Do not use the loss flight size in this case */
+ tp->t_lossflightsize = 0;
}
- thflags = th->th_flags;
+ tp->snd_cwnd = max(tp->snd_cwnd, TCP_CC_CWND_INIT_BYTES);
+ tp->snd_recover = tp->snd_recover_prev;
+ tp->snd_nxt = tp->snd_max;
- /*
- * Convert TCP protocol specific fields to host format.
- */
- NTOHL(th->th_seq);
- NTOHL(th->th_ack);
- NTOHS(th->th_win);
- NTOHS(th->th_urp);
+ /* Fix send socket buffer to reflect the change in cwnd */
+ tcp_bad_rexmt_fix_sndbuf(tp);
/*
- * Drop TCP, IP headers and TCP options.
+ * This RTT might reflect the extra delay induced
+ * by the network. Skip using this sample for RTO
+ * calculation and mark the connection so we can
+ * recompute RTT when the next eligible sample is
+ * found.
*/
- hdroptlen = off+toff;
- m->m_data += hdroptlen;
- m->m_len -= hdroptlen;
+ tp->t_flagsext |= TF_RECOMPUTE_RTT;
+ tp->t_badrexmt_time = tcp_now;
+ tp->t_rtttime = 0;
+}
- /*
- * Locate pcb for segment.
- */
-findpcb:
-#if IPFIREWALL_FORWARD
- if (ip_fw_fwd_addr != NULL
-#if INET6
- && isipv6 == NULL
-#endif /* INET6 */
- ) {
+/*
+ * If the previous packet was sent in retransmission timer, and it was
+ * not needed, then restore the congestion window to the state before that
+ * transmission.
+ *
+ * If the last packet was sent in tail loss probe timeout, check if that
+ * recovered the last packet. If so, that will indicate a real loss and
+ * the congestion window needs to be lowered.
+ */
+static void
+tcp_bad_rexmt_check(struct tcpcb *tp, struct tcphdr *th, struct tcpopt *to)
+{
+ if (tp->t_rxtshift > 0 &&
+ tcp_detect_bad_rexmt(tp, th, to, tp->t_rxtstart)) {
+ ++tcpstat.tcps_sndrexmitbad;
+ tcp_bad_rexmt_restore_state(tp, th);
+ tcp_ccdbg_trace(tp, th, TCP_CC_BAD_REXMT_RECOVERY);
+ } else if ((tp->t_flagsext & TF_SENT_TLPROBE)
+ && tp->t_tlphighrxt > 0
+ && SEQ_GEQ(th->th_ack, tp->t_tlphighrxt)
+ && !tcp_detect_bad_rexmt(tp, th, to, tp->t_tlpstart)) {
/*
- * Diverted. Pretend to be the destination.
- * already got one like this?
+ * check DSACK information also to make sure that
+ * the TLP was indeed needed
*/
- inp = in_pcblookup_hash(&tcbinfo, ip->ip_src, th->th_sport,
- ip->ip_dst, th->th_dport, 0, m->m_pkthdr.rcvif);
- if (!inp) {
- /*
- * No, then it's new. Try find the ambushing socket
+ if (tcp_rxtseg_dsack_for_tlp(tp)) {
+ /*
+ * received a DSACK to indicate that TLP was
+ * not needed
*/
- if (!ip_fw_fwd_addr->sin_port) {
- inp = in_pcblookup_hash(&tcbinfo, ip->ip_src,
- th->th_sport, ip_fw_fwd_addr->sin_addr,
- th->th_dport, 1, m->m_pkthdr.rcvif);
- } else {
- inp = in_pcblookup_hash(&tcbinfo,
- ip->ip_src, th->th_sport,
- ip_fw_fwd_addr->sin_addr,
- ntohs(ip_fw_fwd_addr->sin_port), 1,
- m->m_pkthdr.rcvif);
- }
+ tcp_rxtseg_clean(tp);
+ goto out;
}
- ip_fw_fwd_addr = NULL;
- } else
-#endif /* IPFIREWALL_FORWARD */
-
-#if INET6
- if (isipv6)
- inp = in6_pcblookup_hash(&tcbinfo, &ip6->ip6_src, th->th_sport,
- &ip6->ip6_dst, th->th_dport, 1,
- m->m_pkthdr.rcvif);
- else
-#endif /* INET6 */
- inp = in_pcblookup_hash(&tcbinfo, ip->ip_src, th->th_sport,
- ip->ip_dst, th->th_dport, 1, m->m_pkthdr.rcvif);
-#if IPSEC
- /* due to difference from other BSD stacks */
- m->m_data -= hdroptlen;
- m->m_len += hdroptlen;
-#if INET6
- if (isipv6) {
- if (inp != NULL && ipsec6_in_reject_so(m, inp->inp_socket)) {
- ipsec6stat.in_polvio++;
- goto drop;
+ /*
+ * The tail loss probe recovered the last packet and
+ * we need to adjust the congestion window to take
+ * this loss into account.
+ */
+ ++tcpstat.tcps_tlp_recoverlastpkt;
+ if (!IN_FASTRECOVERY(tp)) {
+ tcp_reduce_congestion_window(tp);
+ EXIT_FASTRECOVERY(tp);
}
- } else
-#endif /* INET6 */
- if (inp != NULL && ipsec4_in_reject_so(m, inp->inp_socket)) {
- ipsecstat.in_polvio++;
- goto drop;
+ tcp_ccdbg_trace(tp, th, TCP_CC_TLP_RECOVER_LASTPACKET);
+ } else if (tcp_rxtseg_detect_bad_rexmt(tp, th->th_ack)) {
+ /*
+ * All of the retransmitted segments were duplicated, this
+ * can be an indication of bad fast retransmit.
+ */
+ tcpstat.tcps_dsack_badrexmt++;
+ tcp_bad_rexmt_restore_state(tp, th);
+ tcp_ccdbg_trace(tp, th, TCP_CC_DSACK_BAD_REXMT);
+ tcp_rxtseg_clean(tp);
}
- m->m_data += hdroptlen;
- m->m_len -= hdroptlen;
-#endif /*IPSEC*/
+out:
+ tp->t_flagsext &= ~(TF_SENT_TLPROBE);
+ tp->t_tlphighrxt = 0;
+ tp->t_tlpstart = 0;
/*
- * If the state is CLOSED (i.e., TCB does not exist) then
- * all data in the incoming segment is discarded.
- * If the TCB exists but is in CLOSED state, it is embryonic,
- * but should either do a listen or a connect soon.
+ * check if the latest ack was for a segment sent during PMTU
+ * blackhole detection. If the timestamp on the ack is before
+ * PMTU blackhole detection, then revert the size of the max
+ * segment to previous size.
*/
- if (inp == NULL) {
- if (log_in_vain && thflags & TH_SYN) {
-#if INET6
- char buf[INET6_ADDRSTRLEN];
-#else /* INET6 */
- char buf[4*sizeof "123"];
-#endif /* INET6 */
-
-#if INET6
- if (isipv6) {
- strcpy(buf, ip6_sprintf(&ip6->ip6_dst));
- log(LOG_INFO,
- "Connection attempt to TCP %s:%d from %s:%d\n",
- buf, ntohs(th->th_dport),
- ip6_sprintf(&ip6->ip6_src),
- ntohs(th->th_sport));
- } else {
-#endif
- strcpy(buf, inet_ntoa(ip->ip_dst));
- log(LOG_INFO,
- "Connection attempt to TCP %s:%d from %s:%d\n",
- buf, ntohs(th->th_dport), inet_ntoa(ip->ip_src),
- ntohs(th->th_sport));
-#if INET6
- }
-#endif /* INET6 */
+ if (tp->t_rxtshift > 0 && (tp->t_flags & TF_BLACKHOLE) &&
+ tp->t_pmtud_start_ts > 0 && TSTMP_SUPPORTED(tp)) {
+ if ((to->to_flags & TOF_TS) && to->to_tsecr != 0
+ && TSTMP_LT(to->to_tsecr, tp->t_pmtud_start_ts)) {
+ tcp_pmtud_revert_segment_size(tp);
}
-#if ICMP_BANDLIM
- if (badport_bandlim(1) < 0)
- goto drop;
-#endif
- goto dropwithreset;
}
- tp = intotcpcb(inp);
- if (tp == 0)
- goto dropwithreset;
- if (tp->t_state == TCPS_CLOSED)
- goto drop;
+ if (tp->t_pmtud_start_ts > 0) {
+ tp->t_pmtud_start_ts = 0;
+ }
+}
- /* Unscale the window into a 32-bit value. */
- if ((thflags & TH_SYN) == 0)
- tiwin = th->th_win << tp->snd_scale;
- else
- tiwin = th->th_win;
-
- so = inp->inp_socket;
- if (so->so_options & (SO_DEBUG|SO_ACCEPTCONN)) {
-#if TCPDEBUG
- if (so->so_options & SO_DEBUG) {
- ostate = tp->t_state;
-#if INET6
- if (isipv6)
- tcp_saveip._tcp_si6 = *ip6;
- else
- tcp_saveip._tcp_si4 = *ip;
-#else /* INET6 */
- tcp_saveip = *ip;
-#endif /* INET6 */
+/*
+ * Check if early retransmit can be attempted according to RFC 5827.
+ *
+ * If packet reordering is detected on a connection, fast recovery will
+ * be delayed until it is clear that the packet was lost and not reordered.
+ * But reordering detection is done only when SACK is enabled.
+ *
+ * On connections that do not support SACK, there is a limit on the number
+ * of early retransmits that can be done per minute. This limit is needed
+ * to make sure that too many packets are not retransmitted when there is
+ * packet reordering.
+ */
+static void
+tcp_early_rexmt_check(struct tcpcb *tp, struct tcphdr *th)
+{
+ u_int32_t obytes, snd_off;
+ int32_t snd_len;
+ struct socket *so = tp->t_inpcb->inp_socket;
- tcp_savetcp = *th;
+ if (early_rexmt && (SACK_ENABLED(tp) ||
+ tp->t_early_rexmt_count < TCP_EARLY_REXMT_LIMIT) &&
+ SEQ_GT(tp->snd_max, tp->snd_una) &&
+ (tp->t_dupacks == 1 ||
+ (SACK_ENABLED(tp) &&
+ !TAILQ_EMPTY(&tp->snd_holes)))) {
+ /*
+ * If there are only a few outstanding
+ * segments on the connection, we might need
+ * to lower the retransmit threshold. This
+ * will allow us to do Early Retransmit as
+ * described in RFC 5827.
+ */
+ if (SACK_ENABLED(tp) &&
+ !TAILQ_EMPTY(&tp->snd_holes)) {
+ obytes = (tp->snd_max - tp->snd_fack) +
+ tp->sackhint.sack_bytes_rexmit;
+ } else {
+ obytes = (tp->snd_max - tp->snd_una);
}
-#endif
- if (so->so_options & SO_ACCEPTCONN) {
- register struct tcpcb *tp0 = tp;
- struct socket *so2;
-#if IPSEC
- struct socket *oso;
-#endif
-#if INET6
- struct inpcb *oinp = sotoinpcb(so);
-#endif /* INET6 */
-#if !IPSEC
- if ((thflags & (TH_RST|TH_ACK|TH_SYN)) != TH_SYN) {
- /*
- * Note: dropwithreset makes sure we don't
- * send a RST in response to a RST.
- */
- if (thflags & TH_ACK) {
- tcpstat.tcps_badsyn++;
- goto dropwithreset;
- }
- goto drop;
+ /*
+ * In order to lower retransmit threshold the
+ * following two conditions must be met.
+ * 1. the amount of outstanding data is less
+ * than 4*SMSS bytes
+ * 2. there is no unsent data ready for
+ * transmission or the advertised window
+ * will limit sending new segments.
+ */
+ snd_off = tp->snd_max - tp->snd_una;
+ snd_len = min(so->so_snd.sb_cc, tp->snd_wnd) - snd_off;
+ if (obytes < (tp->t_maxseg << 2) &&
+ snd_len <= 0) {
+ u_int32_t osegs;
+
+ osegs = obytes / tp->t_maxseg;
+ if ((osegs * tp->t_maxseg) < obytes) {
+ osegs++;
}
-#endif
- KERNEL_DEBUG(DBG_FNC_TCP_NEWCONN | DBG_FUNC_START,0,0,0,0,0);
- so2 = sonewconn(so, 0);
-
- if (so2 == 0) {
- tcpstat.tcps_listendrop++;
- so2 = sodropablereq(so);
- if (so2) {
- tcp_drop(sototcpcb(so2), ETIMEDOUT);
- so2 = sonewconn(so, 0);
- }
- if (!so2)
- goto drop;
- }
-#if IPSEC
- oso = so;
-#endif
- so = so2;
/*
- * This is ugly, but ....
+ * Since the connection might have already
+ * received some dupacks, we add them to
+ * to the outstanding segments count to get
+ * the correct retransmit threshold.
*
- * Mark socket as temporary until we're
- * committed to keeping it. The code at
- * ``drop'' and ``dropwithreset'' check the
- * flag dropsocket to see if the temporary
- * socket created here should be discarded.
- * We mark the socket as discardable until
- * we're committed to it below in TCPS_LISTEN.
+ * By checking for early retransmit after
+ * receiving some duplicate acks when SACK
+ * is supported, the connection will
+ * enter fast recovery even if multiple
+ * segments are lost in the same window.
*/
- dropsocket++;
- inp = (struct inpcb *)so->so_pcb;
-#if INET6
- if (isipv6)
- inp->in6p_laddr = ip6->ip6_dst;
- else {
- if (ip6_mapped_addr_on) {
- inp->inp_vflag &= ~INP_IPV6;
- inp->inp_vflag |= INP_IPV4;
+ osegs += tp->t_dupacks;
+ if (osegs < 4) {
+ tp->t_rexmtthresh =
+ ((osegs - 1) > 1) ? (osegs - 1) : 1;
+ tp->t_rexmtthresh =
+ min(tp->t_rexmtthresh, tcprexmtthresh);
+ tp->t_rexmtthresh =
+ max(tp->t_rexmtthresh, tp->t_dupacks);
+
+ if (tp->t_early_rexmt_count == 0) {
+ tp->t_early_rexmt_win = tcp_now;
}
-#endif /* INET6 */
- inp->inp_laddr = ip->ip_dst;
-#if INET6
- }
-#endif /* INET6 */
- inp->inp_lport = th->th_dport;
- if (in_pcbinshash(inp) != 0) {
- /*
- * Undo the assignments above if we failed to put
- * the PCB on the hash lists.
- */
-#if INET6
- if (isipv6)
- inp->in6p_laddr = in6addr_any;
- else
-#endif /* INET6 */
- inp->inp_laddr.s_addr = INADDR_ANY;
- inp->inp_lport = 0;
- goto drop;
- }
-#if IPSEC
- /*
- * from IPsec perspective, it is important to do it
- * after making actual listening socket.
- * otherwise, cached security association will bark.
- *
- * Subject: (KAME-snap 748)
- * From: Wayne Knowles <w.knowles@niwa.cri.nz>
- */
- if ((thflags & (TH_RST|TH_ACK|TH_SYN)) != TH_SYN) {
- /*
- * Note: dropwithreset makes sure we don't
- * send a RST in response to a RST.
- */
- if (thflags & TH_ACK) {
- tcpstat.tcps_badsyn++;
- goto dropwithreset;
+ if (tp->t_flagsext & TF_SENT_TLPROBE) {
+ tcpstat.tcps_tlp_recovery++;
+ tcp_ccdbg_trace(tp, th,
+ TCP_CC_TLP_RECOVERY);
+ } else {
+ tcpstat.tcps_early_rexmt++;
+ tp->t_early_rexmt_count++;
+ tcp_ccdbg_trace(tp, th,
+ TCP_CC_EARLY_RETRANSMIT);
}
- goto drop;
}
-#endif
-#if INET6
- if (isipv6) {
- struct ip6_recvpktopts newopts;
+ }
+ }
- /*
- * Inherit socket options from the listening
- * socket.
- * Note that in6p_inputopts are not (even
- * should not be) copied, since it stores
- * previously received options and is used to
- * detect if each new option is different than
- * the previous one and hence should be passed
- * to a user.
- * If we copied in6p_inputopts, a user would
- * not be able to receive options just after
- * calling the accept system call.
- */
- inp->inp_flags |=
- oinp->inp_flags & INP_CONTROLOPTS;
- if (oinp->in6p_outputopts)
- inp->in6p_outputopts =
- ip6_copypktopts(oinp->in6p_outputopts,
- M_NOWAIT);
- } else
-#endif /* INET6 */
- inp->inp_options = ip_srcroute();
-#if IPSEC
- /* copy old policy into new socket's */
- if (ipsec_copy_policy(sotoinpcb(oso)->inp_sp,
- inp->inp_sp))
- printf("tcp_input: could not copy policy\n");
-#endif
+ /*
+ * If we ever sent a TLP probe, the acknowledgement will trigger
+ * early retransmit because the value of snd_fack will be close
+ * to snd_max. This will take care of adjustments to the
+ * congestion window. So we can reset TF_SENT_PROBE flag.
+ */
+ tp->t_flagsext &= ~(TF_SENT_TLPROBE);
+ tp->t_tlphighrxt = 0;
+ tp->t_tlpstart = 0;
+}
- tp = intotcpcb(inp);
- tp->t_state = TCPS_LISTEN;
- tp->t_flags |= tp0->t_flags & (TF_NOPUSH|TF_NOOPT);
+static boolean_t
+tcp_tfo_syn(struct tcpcb *tp, struct tcpopt *to)
+{
+ u_char out[CCAES_BLOCK_SIZE];
+ unsigned char len;
+
+ if (!(to->to_flags & (TOF_TFO | TOF_TFOREQ)) ||
+ !(tcp_fastopen & TCP_FASTOPEN_SERVER)) {
+ return FALSE;
+ }
- /* Compute proper scaling value from buffer space */
- while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
- TCP_MAXWIN << tp->request_r_scale < so->so_rcv.sb_hiwat)
- tp->request_r_scale++;
+ if ((to->to_flags & TOF_TFOREQ)) {
+ tp->t_tfo_flags |= TFO_F_OFFER_COOKIE;
- KERNEL_DEBUG(DBG_FNC_TCP_NEWCONN | DBG_FUNC_END,0,0,0,0,0);
- }
+ tp->t_tfo_stats |= TFO_S_COOKIEREQ_RECV;
+ tcpstat.tcps_tfo_cookie_req_rcv++;
+ return FALSE;
}
-#if INET6
- /* save packet options if user wanted */
- if (isipv6 && (inp->in6p_flags & INP_CONTROLOPTS) != 0) {
- struct ip6_recvpktopts opts6;
+ /* Ok, then it must be an offered cookie. We need to check that ... */
+ tcp_tfo_gen_cookie(tp->t_inpcb, out, sizeof(out));
- /*
- * Temporarily re-adjusting the mbuf before ip6_savecontrol(),
- * which is necessary for FreeBSD only due to difference from
- * other BSD stacks.
- * XXX: we'll soon make a more natural fix after getting a
- * consensus.
- */
-#ifndef DEFER_MADJ
- m->m_data -= hdroptlen;
- m->m_len += hdroptlen;
-#endif
- ip6_savecontrol(inp, ip6, m, &opts6, &inp->in6p_inputopts);
- if (inp->in6p_inputopts)
- ip6_update_recvpcbopt(inp->in6p_inputopts, &opts6);
- if (opts6.head) {
- if (sbappendcontrol(&inp->in6p_socket->so_rcv,
- NULL, opts6.head)
- == 0)
- m_freem(opts6.head);
- }
-#ifndef DEFER_MADJ
- m->m_data += hdroptlen; /* XXX */
- m->m_len -= hdroptlen; /* XXX */
-#endif
+ len = *to->to_tfo - TCPOLEN_FASTOPEN_REQ;
+ to->to_tfo++;
+ if (memcmp(out, to->to_tfo, len)) {
+ /* Cookies are different! Let's return and offer a new cookie */
+ tp->t_tfo_flags |= TFO_F_OFFER_COOKIE;
+
+ tp->t_tfo_stats |= TFO_S_COOKIE_INVALID;
+ tcpstat.tcps_tfo_cookie_invalid++;
+ return FALSE;
}
-#endif /* INET6 */
- /*
- * Segment received on connection.
- * Reset idle time and keep-alive timer.
- */
- tp->t_idle = 0;
- if (TCPS_HAVEESTABLISHED(tp->t_state))
- tp->t_timer[TCPT_KEEP] = tcp_keepidle;
+ if (OSIncrementAtomic(&tcp_tfo_halfcnt) >= tcp_tfo_backlog) {
+ /* Need to decrement again as we just increased it... */
+ OSDecrementAtomic(&tcp_tfo_halfcnt);
+ return FALSE;
+ }
- /*
- * Process options if not in LISTEN state,
- * else do it below (after getting remote address).
- */
- if (tp->t_state != TCPS_LISTEN && optp)
- tcp_dooptions(tp, optp, optlen, th, &to);
- if (th->th_flags & TH_SYN)
- tcp_mss(tp, to.to_maxseg, isipv6); /* sets t_maxseg */
+ tp->t_tfo_flags |= TFO_F_COOKIE_VALID;
- /*
- * Header prediction: check for the two common cases
- * of a uni-directional data xfer. If the packet has
- * no control flags, is in-sequence, the window didn't
- * change and we're not retransmitting, it's a
- * candidate. If the length is zero and the ack moved
- * forward, we're the sender side of the xfer. Just
- * free the data acked & wake any higher level process
- * that was blocked waiting for space. If the length
- * is non-zero and the ack didn't move, we're the
- * receiver side. If we're getting packets in-order
- * (the reassembly queue is empty), add the data to
- * the socket buffer and note that we need a delayed ack.
- * Make sure that the hidden state-flags are also off.
- * Since we check for TCPS_ESTABLISHED above, it can only
- * be TH_NEEDSYN.
- */
- if (tp->t_state == TCPS_ESTABLISHED &&
- (thflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ACK)) == TH_ACK &&
- ((tp->t_flags & (TF_NEEDSYN|TF_NEEDFIN)) == 0) &&
- ((to.to_flag & TOF_TS) == 0 ||
- TSTMP_GEQ(to.to_tsval, tp->ts_recent)) &&
- /*
- * Using the CC option is compulsory if once started:
- * the segment is OK if no T/TCP was negotiated or
- * if the segment has a CC option equal to CCrecv
- */
- ((tp->t_flags & (TF_REQ_CC|TF_RCVD_CC)) != (TF_REQ_CC|TF_RCVD_CC) ||
- ((to.to_flag & TOF_CC) != 0 && to.to_cc == tp->cc_recv)) &&
- th->th_seq == tp->rcv_nxt &&
- tiwin && tiwin == tp->snd_wnd &&
- tp->snd_nxt == tp->snd_max) {
+ tp->t_tfo_stats |= TFO_S_SYNDATA_RCV;
+ tcpstat.tcps_tfo_syn_data_rcv++;
+
+ return TRUE;
+}
+
+static void
+tcp_tfo_synack(struct tcpcb *tp, struct tcpopt *to)
+{
+ if (to->to_flags & TOF_TFO) {
+ unsigned char len = *to->to_tfo - TCPOLEN_FASTOPEN_REQ;
/*
- * If last ACK falls within this segment's sequence numbers,
- * record the timestamp.
- * NOTE that the test is modified according to the latest
- * proposal of the tcplw@cray.com list (Braden 1993/04/26).
+ * If this happens, things have gone terribly wrong. len should
+ * have been checked in tcp_dooptions.
*/
- if ((to.to_flag & TOF_TS) != 0 &&
- SEQ_LEQ(th->th_seq, tp->last_ack_sent)) {
- tp->ts_recent_age = tcp_now;
- tp->ts_recent = to.to_tsval;
- }
+ VERIFY(len <= TFO_COOKIE_LEN_MAX);
- if (tilen == 0) {
- if (SEQ_GT(th->th_ack, tp->snd_una) &&
- SEQ_LEQ(th->th_ack, tp->snd_max) &&
- tp->snd_cwnd >= tp->snd_wnd &&
- tp->t_dupacks < tcprexmtthresh) {
- /*
- * this is a pure ack for outstanding data.
- */
- ++tcpstat.tcps_predack;
- if ((to.to_flag & TOF_TS) != 0)
- tcp_xmit_timer(tp,
- tcp_now - to.to_tsecr + 1);
- else if (tp->t_rtt &&
- SEQ_GT(th->th_ack, tp->t_rtseq))
- tcp_xmit_timer(tp, tp->t_rtt);
- acked = th->th_ack - tp->snd_una;
- tcpstat.tcps_rcvackpack++;
- tcpstat.tcps_rcvackbyte += acked;
- sbdrop(&so->so_snd, acked);
- tp->snd_una = th->th_ack;
- m_freem(m);
-#if INET6
- /* some progress has been done */
- if (isipv6)
- ND6_HINT(tp);
-#endif
+ to->to_tfo++;
- /*
- * If all outstanding data are acked, stop
- * retransmit timer, otherwise restart timer
- * using current (possibly backed-off) value.
- * If process is waiting for space,
- * wakeup/selwakeup/signal. If data
- * are ready to send, let tcp_output
- * decide between more output or persist.
- */
- if (tp->snd_una == tp->snd_max)
- tp->t_timer[TCPT_REXMT] = 0;
- else if (tp->t_timer[TCPT_PERSIST] == 0)
- tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;
+ tcp_cache_set_cookie(tp, to->to_tfo, len);
+ tcp_heuristic_tfo_success(tp);
- if (so->so_snd.sb_cc)
- (void) tcp_output(tp);
- sowwakeup(so);
- KERNEL_DEBUG(DBG_FNC_TCP_INPUT | DBG_FUNC_END,0,0,0,0,0);
- return;
- }
- } else if (th->th_ack == tp->snd_una &&
- tp->segq.lh_first == NULL &&
- tilen <= sbspace(&so->so_rcv)) {
- /*
- * this is a pure, in-sequence data packet
- * with nothing on the reassembly queue and
- * we have enough buffer space to take it.
- */
- ++tcpstat.tcps_preddat;
- tp->rcv_nxt += tilen;
- tcpstat.tcps_rcvpack++;
- tcpstat.tcps_rcvbyte += tilen;
-#if INET6
- /* some progress has been done */
- if (isipv6)
- ND6_HINT(tp);
-#endif
- sbappend(&so->so_rcv, m);
- KERNEL_DEBUG(DBG_LAYER_END, ((th->th_dport << 16) | th->th_sport),
- (((th->th_src.s_addr & 0xffff) << 16) | (th->th_dst.s_addr & 0xffff)),
- th->th_seq, th->th_ack, th->th_win);
- if (tcp_delack_enabled) {
- if (last_active_conn_count > DELACK_BITMASK_THRESH)
- TCP_DELACK_BITSET(tp->t_inpcb->hash_element);
- tp->t_flags |= TF_DELACK;
- } else {
- tp->t_flags |= TF_ACKNOW;
- tcp_output(tp);
+ tp->t_tfo_stats |= TFO_S_COOKIE_RCV;
+ tcpstat.tcps_tfo_cookie_rcv++;
+ if (tp->t_tfo_flags & TFO_F_COOKIE_SENT) {
+ tcpstat.tcps_tfo_cookie_wrong++;
+ tp->t_tfo_stats |= TFO_S_COOKIE_WRONG;
+ }
+ } else {
+ /*
+ * Thus, no cookie in the response, but we either asked for one
+ * or sent SYN+DATA. Now, we need to check whether we had to
+ * rexmit the SYN. If that's the case, it's better to start
+ * backing of TFO-cookie requests.
+ */
+ if (!(tp->t_flagsext & TF_FASTOPEN_FORCE_ENABLE) &&
+ tp->t_tfo_flags & TFO_F_SYN_LOSS) {
+ tp->t_tfo_stats |= TFO_S_SYN_LOSS;
+ tcpstat.tcps_tfo_syn_loss++;
+
+ tcp_heuristic_tfo_loss(tp);
+ } else {
+ if (tp->t_tfo_flags & TFO_F_COOKIE_REQ) {
+ tp->t_tfo_stats |= TFO_S_NO_COOKIE_RCV;
+ tcpstat.tcps_tfo_no_cookie_rcv++;
}
- sorwakeup(so);
- KERNEL_DEBUG(DBG_FNC_TCP_INPUT | DBG_FUNC_END,0,0,0,0,0);
- return;
+
+ tcp_heuristic_tfo_success(tp);
}
}
+}
- /*
- * Calculate amount of space in receive window,
- * and then do TCP input processing.
- * Receive window is amount of space in rcv queue,
- * but not less than advertised window.
- */
- { int win;
-
- win = sbspace(&so->so_rcv);
- if (win < 0)
- win = 0;
- tp->rcv_wnd = imax(win, (int)(tp->rcv_adv - tp->rcv_nxt));
+static void
+tcp_tfo_rcv_probe(struct tcpcb *tp, int tlen)
+{
+ if (tlen != 0) {
+ return;
}
- switch (tp->t_state) {
+ tp->t_tfo_probe_state = TFO_PROBE_PROBING;
/*
- * If the state is LISTEN then ignore segment if it contains an RST.
- * If the segment contains an ACK then it is bad and send a RST.
- * If it does not contain a SYN then it is not interesting; drop it.
- * If it is from this socket, drop it, it must be forged.
- * Don't bother responding if the destination was a broadcast.
- * Otherwise initialize tp->rcv_nxt, and tp->irs, select an initial
- * tp->iss, and send a segment:
- * <SEQ=ISS><ACK=RCV_NXT><CTL=SYN,ACK>
- * Also initialize tp->snd_nxt to tp->iss+1 and tp->snd_una to tp->iss.
- * Fill in remote peer address fields if not previously specified.
- * Enter SYN_RECEIVED state, and process any other fields of this
- * segment in this state.
+ * We send the probe out rather quickly (after one RTO). It does not
+ * really hurt that much, it's only one additional segment on the wire.
*/
- case TCPS_LISTEN: {
- register struct sockaddr_in *sin;
-#if 0
- register struct sockaddr_in6 *sin6;
-#endif
+ tp->t_timer[TCPT_KEEP] = OFFSET_FROM_START(tp, (TCP_REXMTVAL(tp)));
+}
- if (thflags & TH_RST)
- goto drop;
- if (thflags & TH_ACK)
- goto dropwithreset;
- if ((thflags & TH_SYN) == 0)
- goto drop;
- if (th->th_dport == th->th_sport) {
-#if INET6
- if (isipv6) {
- if (IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst,
- &ip6->ip6_src))
- goto drop;
- } else
-#endif /* INET6 */
- if (ip->ip_dst.s_addr == ip->ip_src.s_addr)
- goto drop;
+static void
+tcp_tfo_rcv_data(struct tcpcb *tp)
+{
+ /* Transition from PROBING to NONE as data has been received */
+ if (tp->t_tfo_probe_state >= TFO_PROBE_PROBING) {
+ tp->t_tfo_probe_state = TFO_PROBE_NONE;
+ }
+}
+
+static void
+tcp_tfo_rcv_ack(struct tcpcb *tp, struct tcphdr *th)
+{
+ if (tp->t_tfo_probe_state == TFO_PROBE_PROBING &&
+ tp->t_tfo_probes > 0) {
+ if (th->th_seq == tp->rcv_nxt) {
+ /* No hole, so stop probing */
+ tp->t_tfo_probe_state = TFO_PROBE_NONE;
+ } else if (SEQ_GT(th->th_seq, tp->rcv_nxt)) {
+ /* There is a hole! Wait a bit for data... */
+ tp->t_tfo_probe_state = TFO_PROBE_WAIT_DATA;
+ tp->t_timer[TCPT_KEEP] = OFFSET_FROM_START(tp,
+ TCP_REXMTVAL(tp));
}
+ }
+}
-#if INET6
- if (isipv6) {
- if (m->m_flags & (M_BCAST|M_MCAST) ||
- IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst))
- goto drop;
-#if 1
- /*
- * Perhaps this should be a call/macro
- * to a function like in6_pcbconnect(), but almost
- * all of the checks have been done: we know
- * that the association is unique, and the
- * local address is always set here.
- */
- if (IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr))
- inp->in6p_laddr = ip6->ip6_dst;
- inp->in6p_faddr = ip6->ip6_src;
- inp->inp_fport = th->th_sport;
+/*
+ * Update snd_wnd information.
+ */
+static inline bool
+tcp_update_window(struct tcpcb *tp, int thflags, struct tcphdr * th,
+ u_int32_t tiwin, int tlen)
+{
+ /* Don't look at the window if there is no ACK flag */
+ if ((thflags & TH_ACK) &&
+ (SEQ_LT(tp->snd_wl1, th->th_seq) ||
+ (tp->snd_wl1 == th->th_seq && (SEQ_LT(tp->snd_wl2, th->th_ack) ||
+ (tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd))))) {
+ /* keep track of pure window updates */
+ if (tlen == 0 &&
+ tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd) {
+ tcpstat.tcps_rcvwinupd++;
+ }
+ tp->snd_wnd = tiwin;
+ tp->snd_wl1 = th->th_seq;
+ tp->snd_wl2 = th->th_ack;
+ if (tp->snd_wnd > tp->max_sndwnd) {
+ tp->max_sndwnd = tp->snd_wnd;
+ }
- /* TODO: flowinfo initialization */
+ if (tp->t_inpcb->inp_socket->so_flags & SOF_MP_SUBFLOW) {
+ mptcp_update_window_wakeup(tp);
+ }
+ return true;
+ }
+ return false;
+}
- in_pcbrehash(inp);
-#else
- MALLOC(sin6, struct sockaddr_in6 *, sizeof *sin6,
- M_SONAME, M_NOWAIT);
- if (sin6 == NULL)
- goto drop;
- bzero(sin6, sizeof(*sin6));
- sin6->sin6_family = AF_INET6;
- sin6->sin6_len = sizeof(*sin6);
- sin6->sin6_addr = ip6->ip6_src;
- sin6->sin6_port = th->th_sport;
- laddr6 = inp->in6p_laddr;
- if (IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr))
- inp->in6p_laddr = ip6->ip6_dst;
- if (in6_pcbconnect(inp, (struct sockaddr *)sin6,
- &proc0)) {
- inp->in6p_laddr = laddr6;
- FREE(sin6, M_SONAME);
- goto drop;
- }
- FREE(sin6, M_SONAME);
+static void
+tcp_handle_wakeup(struct socket *so, int read_wakeup, int write_wakeup)
+{
+ if (read_wakeup != 0) {
+ sorwakeup(so);
+ }
+ if (write_wakeup != 0) {
+ sowwakeup(so);
+ }
+}
+
+void
+tcp_input(struct mbuf *m, int off0)
+{
+ struct tcphdr *th;
+ struct ip *ip = NULL;
+ struct inpcb *inp;
+ u_char *optp = NULL;
+ int optlen = 0;
+ int tlen, off;
+ int drop_hdrlen;
+ struct tcpcb *tp = 0;
+ int thflags;
+ struct socket *so = 0;
+ int todrop, acked, ourfinisacked, needoutput = 0;
+ int read_wakeup = 0;
+ int write_wakeup = 0;
+ struct in_addr laddr;
+#if INET6
+ struct in6_addr laddr6;
#endif
- }
- else {
-#endif /* INET6 */
- /*
- * RFC1122 4.2.3.10, p. 104: discard bcast/mcast SYN
- * in_broadcast() should never return true on a received
- * packet with M_BCAST not set.
- */
- if (m->m_flags & (M_BCAST|M_MCAST) ||
- IN_MULTICAST(ntohl(ip->ip_dst.s_addr)))
- goto drop;
- MALLOC(sin, struct sockaddr_in *, sizeof *sin, M_SONAME,
- M_NOWAIT);
- if (sin == NULL)
- goto drop;
- sin->sin_family = AF_INET;
- sin->sin_len = sizeof(*sin);
- sin->sin_addr = ip->ip_src;
- sin->sin_port = th->th_sport;
- bzero((caddr_t)sin->sin_zero, sizeof(sin->sin_zero));
- laddr = inp->inp_laddr;
- if (inp->inp_laddr.s_addr == INADDR_ANY)
- inp->inp_laddr = ip->ip_dst;
- if (in_pcbconnect(inp, (struct sockaddr *)sin, &proc0)) {
- inp->inp_laddr = laddr;
- FREE(sin, M_SONAME);
- goto drop;
- }
- FREE(sin, M_SONAME);
+ int dropsocket = 0;
+ int iss = 0, nosock = 0;
+ u_int32_t tiwin, sack_bytes_acked = 0;
+ struct tcpopt to; /* options in this segment */
+#if TCPDEBUG
+ short ostate = 0;
+#endif
+#if IPFIREWALL
+ struct sockaddr_in *next_hop = NULL;
+ struct m_tag *fwd_tag;
+#endif /* IPFIREWALL */
+ u_char ip_ecn = IPTOS_ECN_NOTECT;
+ unsigned int ifscope;
+ uint8_t isconnected, isdisconnected;
+ struct ifnet *ifp = m->m_pkthdr.rcvif;
+ int pktf_sw_lro_pkt = (m->m_pkthdr.pkt_flags & PKTF_SW_LRO_PKT) ? 1 : 0;
+ int nlropkts = (pktf_sw_lro_pkt == 1) ? m->m_pkthdr.lro_npkts : 1;
+ int turnoff_lro = 0, win;
+#if MPTCP
+ struct mptcb *mp_tp = NULL;
+#endif /* MPTCP */
+ boolean_t cell = IFNET_IS_CELLULAR(ifp);
+ boolean_t wifi = (!cell && IFNET_IS_WIFI(ifp));
+ boolean_t wired = (!wifi && IFNET_IS_WIRED(ifp));
+ boolean_t recvd_dsack = FALSE;
+ struct tcp_respond_args tra;
+ int prev_t_state;
+ boolean_t check_cfil = cfil_filter_present();
+ bool findpcb_iterated = false;
+ /*
+ * The mbuf may be freed after it has been added to the receive socket
+ * buffer or the reassembly queue, so we reinitialize th to point to a
+ * safe copy of the TCP header
+ */
+ struct tcphdr saved_tcphdr = {};
+ /*
+ * Save copy of the IPv4/IPv6 header.
+ * Note: use array of uint32_t to silence compiler warning when casting
+ * to a struct ip6_hdr pointer.
+ */
+#define MAX_IPWORDS ((sizeof(struct ip) + MAX_IPOPTLEN) / sizeof(uint32_t))
+ uint32_t saved_hdr[MAX_IPWORDS];
+
+#define TCP_INC_VAR(stat, npkts) do { \
+ stat += npkts; \
+} while (0)
+
+ TCP_INC_VAR(tcpstat.tcps_rcvtotal, nlropkts);
+#if IPFIREWALL
+ /* Grab info from PACKET_TAG_IPFORWARD tag prepended to the chain. */
+ if (!SLIST_EMPTY(&m->m_pkthdr.tags)) {
+ fwd_tag = m_tag_locate(m, KERNEL_MODULE_TAG_ID,
+ KERNEL_TAG_TYPE_IPFORWARD, NULL);
+ } else {
+ fwd_tag = NULL;
+ }
+ if (fwd_tag != NULL) {
+ struct ip_fwd_tag *ipfwd_tag =
+ (struct ip_fwd_tag *)(fwd_tag + 1);
+
+ next_hop = ipfwd_tag->next_hop;
+ m_tag_delete(m, fwd_tag);
+ }
+#endif /* IPFIREWALL */
+
#if INET6
- }
+ struct ip6_hdr *ip6 = NULL;
+ int isipv6;
#endif /* INET6 */
+ int rstreason; /* For badport_bandlim accounting purposes */
+ struct proc *proc0 = current_proc();
- tp->t_template = tcp_template(tp);
- if (tp->t_template == 0) {
- tp = tcp_drop(tp, ENOBUFS);
- dropsocket = 0; /* socket is already gone */
- goto drop;
- }
- if ((taop = tcp_gettaocache(inp)) == NULL) {
- taop = &tao_noncached;
- bzero(taop, sizeof(*taop));
+ KERNEL_DEBUG(DBG_FNC_TCP_INPUT | DBG_FUNC_START, 0, 0, 0, 0, 0);
+
+#if INET6
+ isipv6 = (mtod(m, struct ip *)->ip_v == 6) ? 1 : 0;
+#endif
+ bzero((char *)&to, sizeof(to));
+
+#if INET6
+ if (isipv6) {
+ /*
+ * Expect 32-bit aligned data pointer on
+ * strict-align platforms
+ */
+ MBUF_STRICT_DATA_ALIGNMENT_CHECK_32(m);
+
+ /* IP6_EXTHDR_CHECK() is already done at tcp6_input() */
+ ip6 = mtod(m, struct ip6_hdr *);
+ tlen = sizeof(*ip6) + ntohs(ip6->ip6_plen) - off0;
+ th = (struct tcphdr *)(void *)((caddr_t)ip6 + off0);
+
+ if (tcp_input_checksum(AF_INET6, m, th, off0, tlen)) {
+ TCP_LOG_DROP_PKT(ip6, th, ifp, "IPv6 bad tcp checksum");
+ goto dropnosock;
}
- tcp_dooptions(tp, optp, optlen, th, &to);
- if (th->th_flags & TH_SYN)
- tcp_mss(tp, to.to_maxseg, isipv6); /* sets t_maxseg */
- if (iss)
- tp->iss = iss;
- else
- tp->iss = tcp_iss;
- tcp_iss += TCP_ISSINCR/4;
- tp->irs = th->th_seq;
- tcp_sendseqinit(tp);
- tcp_rcvseqinit(tp);
+
+ KERNEL_DEBUG(DBG_LAYER_BEG, ((th->th_dport << 16) | th->th_sport),
+ (((ip6->ip6_src.s6_addr16[0]) << 16) | (ip6->ip6_dst.s6_addr16[0])),
+ th->th_seq, th->th_ack, th->th_win);
/*
- * Initialization of the tcpcb for transaction;
- * set SND.WND = SEG.WND,
- * initialize CCsend and CCrecv.
+ * Be proactive about unspecified IPv6 address in source.
+ * As we use all-zero to indicate unbounded/unconnected pcb,
+ * unspecified IPv6 address can be used to confuse us.
+ *
+ * Note that packets with unspecified IPv6 destination is
+ * already dropped in ip6_input.
*/
- tp->snd_wnd = tiwin; /* initial send-window */
- tp->cc_send = CC_INC(tcp_ccgen);
- tp->cc_recv = to.to_cc;
+ if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) {
+ /* XXX stat */
+ IF_TCP_STATINC(ifp, unspecv6);
+ TCP_LOG_DROP_PKT(ip6, th, ifp, "src IPv6 address unspecified");
+ goto dropnosock;
+ }
+ DTRACE_TCP5(receive, struct mbuf *, m, struct inpcb *, NULL,
+ struct ip6_hdr *, ip6, struct tcpcb *, NULL,
+ struct tcphdr *, th);
+
+ ip_ecn = (ntohl(ip6->ip6_flow) >> 20) & IPTOS_ECN_MASK;
+ } else
+#endif /* INET6 */
+ {
/*
- * Perform TAO test on incoming CC (SEG.CC) option, if any.
- * - compare SEG.CC against cached CC from the same host,
- * if any.
- * - if SEG.CC > chached value, SYN must be new and is accepted
- * immediately: save new CC in the cache, mark the socket
- * connected, enter ESTABLISHED state, turn on flag to
- * send a SYN in the next segment.
- * A virtual advertised window is set in rcv_adv to
- * initialize SWS prevention. Then enter normal segment
- * processing: drop SYN, process data and FIN.
- * - otherwise do a normal 3-way handshake.
- */
- if ((to.to_flag & TOF_CC) != 0) {
- if (((tp->t_flags & TF_NOPUSH) != 0) &&
- taop->tao_cc != 0 && CC_GT(to.to_cc, taop->tao_cc)) {
-
- taop->tao_cc = to.to_cc;
- if (tp->t_state != TCPS_ESTABLISHED)
- current_active_connections++;
+ * Get IP and TCP header together in first mbuf.
+ * Note: IP leaves IP header in first mbuf.
+ */
+ if (off0 > sizeof(struct ip)) {
+ ip_stripoptions(m);
+ off0 = sizeof(struct ip);
+ }
+ if (m->m_len < sizeof(struct tcpiphdr)) {
+ if ((m = m_pullup(m, sizeof(struct tcpiphdr))) == 0) {
+ tcpstat.tcps_rcvshort++;
+ return;
+ }
+ }
- tp->t_state = TCPS_ESTABLISHED;
+ /* Expect 32-bit aligned data pointer on strict-align platforms */
+ MBUF_STRICT_DATA_ALIGNMENT_CHECK_32(m);
+
+ ip = mtod(m, struct ip *);
+ th = (struct tcphdr *)(void *)((caddr_t)ip + off0);
+ tlen = ip->ip_len;
+
+ if (tcp_input_checksum(AF_INET, m, th, off0, tlen)) {
+ TCP_LOG_DROP_PKT(ip, th, ifp, "IPv4 bad tcp checksum");
+ goto dropnosock;
+ }
- /*
- * If there is a FIN, or if there is data and the
- * connection is local, then delay SYN,ACK(SYN) in
- * the hope of piggy-backing it on a response
- * segment. Otherwise must send ACK now in case
- * the other side is slow starting.
- */
- if (tcp_delack_enabled &&
- ((thflags & TH_FIN) ||
- (tilen != 0 &&
#if INET6
- (isipv6 && in6_localaddr(&inp->in6p_faddr))
- ||
- (!isipv6 &&
-#endif /* INET6 */
- in_localaddr(inp->inp_faddr)
+ /* Re-initialization for later version check */
+ ip->ip_v = IPVERSION;
+#endif
+ ip_ecn = (ip->ip_tos & IPTOS_ECN_MASK);
+
+ DTRACE_TCP5(receive, struct mbuf *, m, struct inpcb *, NULL,
+ struct ip *, ip, struct tcpcb *, NULL, struct tcphdr *, th);
+
+ KERNEL_DEBUG(DBG_LAYER_BEG, ((th->th_dport << 16) | th->th_sport),
+ (((ip->ip_src.s_addr & 0xffff) << 16) | (ip->ip_dst.s_addr & 0xffff)),
+ th->th_seq, th->th_ack, th->th_win);
+ }
+
+#define TCP_LOG_HDR (isipv6 ? (void *)ip6 : (void *)ip)
+
+ /*
+ * Check that TCP offset makes sense,
+ * pull out TCP options and adjust length.
+ */
+ off = th->th_off << 2;
+ if (off < sizeof(struct tcphdr) || off > tlen) {
+ tcpstat.tcps_rcvbadoff++;
+ IF_TCP_STATINC(ifp, badformat);
+ TCP_LOG_DROP_PKT(TCP_LOG_HDR, th, ifp, "bad tcp offset");
+ goto dropnosock;
+ }
+ tlen -= off; /* tlen is used instead of ti->ti_len */
+ if (off > sizeof(struct tcphdr)) {
#if INET6
- )
+ if (isipv6) {
+ IP6_EXTHDR_CHECK(m, off0, off, return );
+ ip6 = mtod(m, struct ip6_hdr *);
+ th = (struct tcphdr *)(void *)((caddr_t)ip6 + off0);
+ } else
#endif /* INET6 */
- ))) {
- if (last_active_conn_count > DELACK_BITMASK_THRESH)
- TCP_DELACK_BITSET(tp->t_inpcb->hash_element);
-
- tp->t_flags |= (TF_DELACK | TF_NEEDSYN);
+ {
+ if (m->m_len < sizeof(struct ip) + off) {
+ if ((m = m_pullup(m, sizeof(struct ip) + off)) == 0) {
+ tcpstat.tcps_rcvshort++;
+ return;
+ }
+ ip = mtod(m, struct ip *);
+ th = (struct tcphdr *)(void *)((caddr_t)ip + off0);
}
- else
- tp->t_flags |= (TF_ACKNOW | TF_NEEDSYN);
-
- /*
- * Limit the `virtual advertised window' to TCP_MAXWIN
- * here. Even if we requested window scaling, it will
- * become effective only later when our SYN is acked.
- */
- tp->rcv_adv += min(tp->rcv_wnd, TCP_MAXWIN);
- tcpstat.tcps_connects++;
- soisconnected(so);
- tp->t_timer[TCPT_KEEP] = tcp_keepinit;
- dropsocket = 0; /* committed to socket */
- tcpstat.tcps_accepts++;
- goto trimthenstep6;
- }
- /* else do standard 3-way handshake */
- } else {
- /*
- * No CC option, but maybe CC.NEW:
- * invalidate cached value.
- */
- taop->tao_cc = 0;
}
+ optlen = off - sizeof(struct tcphdr);
+ optp = (u_char *)(th + 1);
/*
- * TAO test failed or there was no CC option,
- * do a standard 3-way handshake.
+ * Do quick retrieval of timestamp options ("options
+ * prediction?"). If timestamp is the only option and it's
+ * formatted as recommended in RFC 1323 appendix A, we
+ * quickly get the values now and not bother calling
+ * tcp_dooptions(), etc.
*/
- tp->t_flags |= TF_ACKNOW;
- tp->t_state = TCPS_SYN_RECEIVED;
- tp->t_timer[TCPT_KEEP] = tcp_keepinit;
- dropsocket = 0; /* committed to socket */
- tcpstat.tcps_accepts++;
- goto trimthenstep6;
+ if ((optlen == TCPOLEN_TSTAMP_APPA ||
+ (optlen > TCPOLEN_TSTAMP_APPA &&
+ optp[TCPOLEN_TSTAMP_APPA] == TCPOPT_EOL)) &&
+ *(u_int32_t *)(void *)optp == htonl(TCPOPT_TSTAMP_HDR) &&
+ (th->th_flags & TH_SYN) == 0) {
+ to.to_flags |= TOF_TS;
+ to.to_tsval = ntohl(*(u_int32_t *)(void *)(optp + 4));
+ to.to_tsecr = ntohl(*(u_int32_t *)(void *)(optp + 8));
+ optp = NULL; /* we've parsed the options */
}
+ }
+ thflags = th->th_flags;
+#if TCP_DROP_SYNFIN
/*
- * If the state is SYN_RECEIVED:
- * if seg contains an ACK, but not for our SYN/ACK, send a RST.
+ * If the drop_synfin option is enabled, drop all packets with
+ * both the SYN and FIN bits set. This prevents e.g. nmap from
+ * identifying the TCP/IP stack.
+ *
+ * This is a violation of the TCP specification.
*/
- case TCPS_SYN_RECEIVED:
- if ((thflags & TH_ACK) &&
- (SEQ_LEQ(th->th_ack, tp->snd_una) ||
- SEQ_GT(th->th_ack, tp->snd_max)))
- goto dropwithreset;
- break;
+ if (drop_synfin && (thflags & (TH_SYN | TH_FIN)) == (TH_SYN | TH_FIN)) {
+ IF_TCP_STATINC(ifp, synfin);
+ TCP_LOG_DROP_PKT(TCP_LOG_HDR, th, ifp, "drop SYN FIN");
+ goto dropnosock;
+ }
+#endif
/*
- * If the state is SYN_SENT:
- * if seg contains an ACK, but not for our SYN, drop the input.
- * if seg contains a RST, then drop the connection.
- * if seg does not contain SYN, then drop it.
- * Otherwise this is an acceptable SYN segment
- * initialize tp->rcv_nxt and tp->irs
- * if seg contains ack then advance tp->snd_una
- * if SYN has been acked change to ESTABLISHED else SYN_RCVD state
- * arrange for segment to be acked (eventually)
- * continue processing rest of data/controls, beginning with URG
+ * Delay dropping TCP, IP headers, IPv6 ext headers, and TCP options,
+ * until after ip6_savecontrol() is called and before other functions
+ * which don't want those proto headers.
+ * Because ip6_savecontrol() is going to parse the mbuf to
+ * search for data to be passed up to user-land, it wants mbuf
+ * parameters to be unchanged.
*/
- case TCPS_SYN_SENT:
- if ((taop = tcp_gettaocache(inp)) == NULL) {
- taop = &tao_noncached;
- bzero(taop, sizeof(*taop));
- }
+ drop_hdrlen = off0 + off;
- if ((thflags & TH_ACK) &&
- (SEQ_LEQ(th->th_ack, tp->iss) ||
- SEQ_GT(th->th_ack, tp->snd_max))) {
- /*
- * If we have a cached CCsent for the remote host,
- * hence we haven't just crashed and restarted,
- * do not send a RST. This may be a retransmission
- * from the other side after our earlier ACK was lost.
- * Our new SYN, when it arrives, will serve as the
- * needed ACK.
- */
- if (taop->tao_ccsent != 0)
- goto drop;
- else
- goto dropwithreset;
- }
- if (thflags & TH_RST) {
- if (thflags & TH_ACK) {
- tp = tcp_drop(tp, ECONNREFUSED);
- postevent(so, 0, EV_RESET);
- }
- goto drop;
- }
- if ((thflags & TH_SYN) == 0)
- goto drop;
- tp->snd_wnd = th->th_win; /* initial send window */
- tp->cc_recv = to.to_cc; /* foreign CC */
+ /* Since this is an entry point for input processing of tcp packets, we
+ * can update the tcp clock here.
+ */
+ calculate_tcp_clock();
- tp->irs = th->th_seq;
- tcp_rcvseqinit(tp);
- if (thflags & TH_ACK) {
- /*
- * Our SYN was acked. If segment contains CC.ECHO
- * option, check it to make sure this segment really
- * matches our SYN. If not, just drop it as old
- * duplicate, but send an RST if we're still playing
- * by the old rules. If no CC.ECHO option, make sure
- * we don't get fooled into using T/TCP.
- */
- if (to.to_flag & TOF_CCECHO) {
- if (tp->cc_send != to.to_ccecho)
- if (taop->tao_ccsent != 0)
- goto drop;
- else
- goto dropwithreset;
- } else
- tp->t_flags &= ~TF_RCVD_CC;
- tcpstat.tcps_connects++;
- soisconnected(so);
- /* Do window scaling on this connection? */
- if ((tp->t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) ==
- (TF_RCVD_SCALE|TF_REQ_SCALE)) {
- tp->snd_scale = tp->requested_s_scale;
- tp->rcv_scale = tp->request_r_scale;
- }
- /* Segment is acceptable, update cache if undefined. */
- if (taop->tao_ccsent == 0)
- taop->tao_ccsent = to.to_ccecho;
+ /*
+ * Record the interface where this segment arrived on; this does not
+ * affect normal data output (for non-detached TCP) as it provides a
+ * hint about which route and interface to use for sending in the
+ * absence of a PCB, when scoped routing (and thus source interface
+ * selection) are enabled.
+ */
+ if ((m->m_pkthdr.pkt_flags & PKTF_LOOP) || m->m_pkthdr.rcvif == NULL) {
+ ifscope = IFSCOPE_NONE;
+ } else {
+ ifscope = m->m_pkthdr.rcvif->if_index;
+ }
+
+ /*
+ * Convert TCP protocol specific fields to host format.
+ */
+
+#if BYTE_ORDER != BIG_ENDIAN
+ NTOHL(th->th_seq);
+ NTOHL(th->th_ack);
+ NTOHS(th->th_win);
+ NTOHS(th->th_urp);
+#endif
+
+ /*
+ * Locate pcb for segment.
+ */
+findpcb:
+
+ isconnected = FALSE;
+ isdisconnected = FALSE;
- tp->rcv_adv += tp->rcv_wnd;
- tp->snd_una++; /* SYN is acked */
+#if IPFIREWALL_FORWARD
+ if (next_hop != NULL
+#if INET6
+ && isipv6 == 0 /* IPv6 support is not yet */
+#endif /* INET6 */
+ ) {
+ /*
+ * Diverted. Pretend to be the destination.
+ * already got one like this?
+ */
+ inp = in_pcblookup_hash(&tcbinfo, ip->ip_src, th->th_sport,
+ ip->ip_dst, th->th_dport, 0, m->m_pkthdr.rcvif);
+ if (!inp) {
/*
- * If there's data, delay ACK; if there's also a FIN
- * ACKNOW will be turned on later.
+ * No, then it's new. Try find the ambushing socket
*/
- if (tcp_delack_enabled && tilen != 0) {
- if (last_active_conn_count > DELACK_BITMASK_THRESH)
- TCP_DELACK_BITSET(tp->t_inpcb->hash_element);
- tp->t_flags |= TF_DELACK;
- }
- else
- tp->t_flags |= TF_ACKNOW;
- /*
- * Received <SYN,ACK> in SYN_SENT[*] state.
- * Transitions:
- * SYN_SENT --> ESTABLISHED
- * SYN_SENT* --> FIN_WAIT_1
- */
- if (tp->t_flags & TF_NEEDFIN) {
- tp->t_state = TCPS_FIN_WAIT_1;
- tp->t_flags &= ~TF_NEEDFIN;
- thflags &= ~TH_SYN;
- } else {
- if (tp->t_state != TCPS_ESTABLISHED)
- current_active_connections++;
- tp->t_state = TCPS_ESTABLISHED;
- tp->t_timer[TCPT_KEEP] = tcp_keepidle;
- }
- } else {
- /*
- * Received initial SYN in SYN-SENT[*] state => simul-
- * taneous open. If segment contains CC option and there is
- * a cached CC, apply TAO test; if it succeeds, connection is
- * half-synchronized. Otherwise, do 3-way handshake:
- * SYN-SENT -> SYN-RECEIVED
- * SYN-SENT* -> SYN-RECEIVED*
- * If there was no CC option, clear cached CC value.
- */
- tp->t_flags |= TF_ACKNOW;
- tp->t_timer[TCPT_REXMT] = 0;
- if (to.to_flag & TOF_CC) {
- if (taop->tao_cc != 0 &&
- CC_GT(to.to_cc, taop->tao_cc)) {
- /*
- * update cache and make transition:
- * SYN-SENT -> ESTABLISHED*
- * SYN-SENT* -> FIN-WAIT-1*
- */
- taop->tao_cc = to.to_cc;
- if (tp->t_flags & TF_NEEDFIN) {
- tp->t_state = TCPS_FIN_WAIT_1;
- tp->t_flags &= ~TF_NEEDFIN;
- } else {
- if (tp->t_state != TCPS_ESTABLISHED)
- current_active_connections++;
- tp->t_state = TCPS_ESTABLISHED;
- tp->t_timer[TCPT_KEEP] = tcp_keepidle;
- }
- tp->t_flags |= TF_NEEDSYN;
- } else
- tp->t_state = TCPS_SYN_RECEIVED;
+ if (!next_hop->sin_port) {
+ inp = in_pcblookup_hash(&tcbinfo, ip->ip_src,
+ th->th_sport, next_hop->sin_addr,
+ th->th_dport, 1, m->m_pkthdr.rcvif);
} else {
- /* CC.NEW or no option => invalidate cache */
- taop->tao_cc = 0;
- tp->t_state = TCPS_SYN_RECEIVED;
+ inp = in_pcblookup_hash(&tcbinfo,
+ ip->ip_src, th->th_sport,
+ next_hop->sin_addr,
+ ntohs(next_hop->sin_port), 1,
+ m->m_pkthdr.rcvif);
}
}
+ } else
+#endif /* IPFIREWALL_FORWARD */
+ {
+#if INET6
+ if (isipv6) {
+ inp = in6_pcblookup_hash(&tcbinfo, &ip6->ip6_src, th->th_sport,
+ &ip6->ip6_dst, th->th_dport, 1,
+ m->m_pkthdr.rcvif);
+ } else
+#endif /* INET6 */
+ inp = in_pcblookup_hash(&tcbinfo, ip->ip_src, th->th_sport,
+ ip->ip_dst, th->th_dport, 1, m->m_pkthdr.rcvif);
+ }
-trimthenstep6:
- /*
- * Advance th->th_seq to correspond to first data byte.
- * If data, trim to stay within window,
- * dropping FIN if necessary.
- */
- th->th_seq++;
- if (tilen > tp->rcv_wnd) {
- todrop = tilen - tp->rcv_wnd;
- m_adj(m, -todrop);
- tilen = tp->rcv_wnd;
- thflags &= ~TH_FIN;
- tcpstat.tcps_rcvpackafterwin++;
- tcpstat.tcps_rcvbyteafterwin += todrop;
- }
- tp->snd_wl1 = th->th_seq - 1;
- tp->rcv_up = th->th_seq;
- /*
- * Client side of transaction: already sent SYN and data.
- * If the remote host used T/TCP to validate the SYN,
- * our data will be ACK'd; if so, enter normal data segment
- * processing in the middle of step 5, ack processing.
- * Otherwise, goto step 6.
- */
- if (thflags & TH_ACK)
- goto process_ACK;
- goto step6;
/*
- * If the state is LAST_ACK or CLOSING or TIME_WAIT:
- * if segment contains a SYN and CC [not CC.NEW] option:
- * if state == TIME_WAIT and connection duration > MSL,
- * drop packet and send RST;
- *
- * if SEG.CC > CCrecv then is new SYN, and can implicitly
- * ack the FIN (and data) in retransmission queue.
- * Complete close and delete TCPCB. Then reprocess
- * segment, hoping to find new TCPCB in LISTEN state;
- *
- * else must be old SYN; drop it.
- * else do normal processing.
+ * Use the interface scope information from the PCB for outbound
+ * segments. If the PCB isn't present and if scoped routing is
+ * enabled, tcp_respond will use the scope of the interface where
+ * the segment arrived on.
*/
- case TCPS_LAST_ACK:
- case TCPS_CLOSING:
- case TCPS_TIME_WAIT:
- if ((thflags & TH_SYN) &&
- (to.to_flag & TOF_CC) && tp->cc_recv != 0) {
- if (tp->t_state == TCPS_TIME_WAIT &&
- tp->t_duration > TCPTV_MSL)
- goto dropwithreset;
- if (CC_GT(to.to_cc, tp->cc_recv)) {
- tp = tcp_close(tp);
- goto findpcb;
- }
- else
- goto drop;
- }
- break; /* continue normal processing */
+ if (inp != NULL && (inp->inp_flags & INP_BOUND_IF)) {
+ ifscope = inp->inp_boundifp->if_index;
}
/*
- * States other than LISTEN or SYN_SENT.
- * First check the RST flag and sequence number since reset segments
- * are exempt from the timestamp and connection count tests. This
- * fixes a bug introduced by the Stevens, vol. 2, p. 960 bugfix
- * below which allowed reset segments in half the sequence space
- * to fall though and be processed (which gives forged reset
- * segments with a random sequence number a 50 percent chance of
- * killing a connection).
- * Then check timestamp, if present.
- * Then check the connection count, if present.
- * Then check that at least some bytes of segment are within
- * receive window. If segment begins before rcv_nxt,
- * drop leading data (and SYN); if nothing left, just ack.
- *
- *
- * If the RST bit is set, check the sequence number to see
- * if this is a valid reset segment.
- * RFC 793 page 37:
- * In all states except SYN-SENT, all reset (RST) segments
- * are validated by checking their SEQ-fields. A reset is
- * valid if its sequence number is in the window.
- * Note: this does not take into account delayed ACKs, so
- * we should test against last_ack_sent instead of rcv_nxt.
- * Also, it does not make sense to allow reset segments with
- * sequence numbers greater than last_ack_sent to be processed
- * since these sequence numbers are just the acknowledgement
- * numbers in our outgoing packets being echoed back at us,
- * and these acknowledgement numbers are monotonically
- * increasing.
- * If we have multiple segments in flight, the intial reset
- * segment sequence numbers will be to the left of last_ack_sent,
- * but they will eventually catch up.
- * In any case, it never made sense to trim reset segments to
- * fit the receive window since RFC 1122 says:
- * 4.2.2.12 RST Segment: RFC-793 Section 3.4
- *
- * A TCP SHOULD allow a received RST segment to include data.
- *
- * DISCUSSION
- * It has been suggested that a RST segment could contain
- * ASCII text that encoded and explained the cause of the
- * RST. No standard has yet been established for such
- * data.
- *
- * If the reset segment passes the sequence number test examine
- * the state:
- * SYN_RECEIVED STATE:
- * If passive open, return to LISTEN state.
- * If active open, inform user that connection was refused.
- * ESTABLISHED, FIN_WAIT_1, FIN_WAIT2, CLOSE_WAIT STATES:
- * Inform user that connection was reset, and close tcb.
- * CLOSING, LAST_ACK, TIME_WAIT STATES
- * Close the tcb.
- * TIME_WAIT state:
- * Drop the segment - see Stevens, vol. 2, p. 964 and
- * RFC 1337.
+ * If the state is CLOSED (i.e., TCB does not exist) then
+ * all data in the incoming segment is discarded.
+ * If the TCB exists but is in CLOSED state, it is embryonic,
+ * but should either do a listen or a connect soon.
*/
- if (thflags & TH_RST) {
- if (tp->last_ack_sent == th->th_seq) {
- switch (tp->t_state) {
-
- case TCPS_SYN_RECEIVED:
- so->so_error = ECONNREFUSED;
- goto close;
+ if (inp == NULL) {
+ if (log_in_vain) {
+#if INET6
+ char dbuf[MAX_IPv6_STR_LEN], sbuf[MAX_IPv6_STR_LEN];
+#else /* INET6 */
+ char dbuf[MAX_IPv4_STR_LEN], sbuf[MAX_IPv4_STR_LEN];
+#endif /* INET6 */
- case TCPS_ESTABLISHED:
- case TCPS_FIN_WAIT_1:
- case TCPS_CLOSE_WAIT:
- current_active_connections--;
- /*
- Drop through ...
- */
- case TCPS_FIN_WAIT_2:
- so->so_error = ECONNRESET;
- close:
- postevent(so, 0, EV_RESET);
- tp->t_state = TCPS_CLOSED;
- tcpstat.tcps_drops++;
- tp = tcp_close(tp);
+#if INET6
+ if (isipv6) {
+ inet_ntop(AF_INET6, &ip6->ip6_dst, dbuf, sizeof(dbuf));
+ inet_ntop(AF_INET6, &ip6->ip6_src, sbuf, sizeof(sbuf));
+ } else
+#endif
+ {
+ inet_ntop(AF_INET, &ip->ip_dst, dbuf, sizeof(dbuf));
+ inet_ntop(AF_INET, &ip->ip_src, sbuf, sizeof(sbuf));
+ }
+ switch (log_in_vain) {
+ case 1:
+ if (thflags & TH_SYN) {
+ log(LOG_INFO,
+ "Connection attempt to TCP %s:%d from %s:%d\n",
+ dbuf, ntohs(th->th_dport),
+ sbuf,
+ ntohs(th->th_sport));
+ }
break;
-
- case TCPS_CLOSING:
- case TCPS_LAST_ACK:
- current_active_connections--;
- tp = tcp_close(tp);
+ case 2:
+ log(LOG_INFO,
+ "Connection attempt to TCP %s:%d from %s:%d flags:0x%x\n",
+ dbuf, ntohs(th->th_dport), sbuf,
+ ntohs(th->th_sport), thflags);
break;
-
- case TCPS_TIME_WAIT:
+ case 3:
+ case 4:
+ if ((thflags & TH_SYN) && !(thflags & TH_ACK) &&
+ !(m->m_flags & (M_BCAST | M_MCAST)) &&
+#if INET6
+ ((isipv6 && !IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst, &ip6->ip6_src)) ||
+ (!isipv6 && ip->ip_dst.s_addr != ip->ip_src.s_addr))
+#else
+ ip->ip_dst.s_addr != ip->ip_src.s_addr
+#endif
+ ) {
+ log_in_vain_log((LOG_INFO,
+ "Stealth Mode connection attempt to TCP %s:%d from %s:%d\n",
+ dbuf, ntohs(th->th_dport),
+ sbuf,
+ ntohs(th->th_sport)));
+ }
+ break;
+ default:
break;
}
}
- goto drop;
+ if (blackhole) {
+ if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_type != IFT_LOOP) {
+ switch (blackhole) {
+ case 1:
+ if (thflags & TH_SYN) {
+ TCP_LOG_DROP_PKT(TCP_LOG_HDR, th, ifp, "blackhole 1 syn for closed port");
+ goto dropnosock;
+ }
+ break;
+ case 2:
+ TCP_LOG_DROP_PKT(TCP_LOG_HDR, th, ifp, "blackhole 2 closed port");
+ goto dropnosock;
+ default:
+ TCP_LOG_DROP_PKT(TCP_LOG_HDR, th, ifp, "blackhole closed port");
+ goto dropnosock;
+ }
+ }
+ }
+ rstreason = BANDLIM_RST_CLOSEDPORT;
+ IF_TCP_STATINC(ifp, noconnnolist);
+ TCP_LOG_DROP_PKT(TCP_LOG_HDR, th, ifp, "closed port");
+ goto dropwithresetnosock;
+ }
+ so = inp->inp_socket;
+ if (so == NULL) {
+ /* This case shouldn't happen as the socket shouldn't be null
+ * if inp_state isn't set to INPCB_STATE_DEAD
+ * But just in case, we pretend we didn't find the socket if we hit this case
+ * as this isn't cause for a panic (the socket might be leaked however)...
+ */
+ inp = NULL;
+#if TEMPDEBUG
+ printf("tcp_input: no more socket for inp=%x. This shouldn't happen\n", inp);
+#endif
+ TCP_LOG_DROP_PKT(TCP_LOG_HDR, th, ifp, "inp_socket NULL");
+ goto dropnosock;
}
- /*
- * RFC 1323 PAWS: If we have a timestamp reply on this segment
- * and it's less than ts_recent, drop it.
- */
- if ((to.to_flag & TOF_TS) != 0 && tp->ts_recent &&
- TSTMP_LT(to.to_tsval, tp->ts_recent)) {
+ socket_lock(so, 1);
+ if (in_pcb_checkstate(inp, WNT_RELEASE, 1) == WNT_STOPUSING) {
+ socket_unlock(so, 1);
+ inp = NULL; // pretend we didn't find it
+ TCP_LOG_DROP_PKT(TCP_LOG_HDR, th, ifp, "inp state WNT_STOPUSING");
+ goto dropnosock;
+ }
- /* Check to see if ts_recent is over 24 days old. */
- if ((int)(tcp_now - tp->ts_recent_age) > TCP_PAWS_IDLE) {
- /*
- * Invalidate ts_recent. If this segment updates
- * ts_recent, the age will be reset later and ts_recent
- * will get a valid value. If it does not, setting
- * ts_recent to zero will at least satisfy the
- * requirement that zero be placed in the timestamp
- * echo reply when ts_recent isn't valid. The
- * age isn't reset until we get a valid ts_recent
- * because we don't want out-of-order segments to be
- * dropped when ts_recent is old.
- */
- tp->ts_recent = 0;
- } else {
- tcpstat.tcps_rcvduppack++;
- tcpstat.tcps_rcvdupbyte += tilen;
- tcpstat.tcps_pawsdrop++;
- goto dropafterack;
+ if (!isipv6 && inp->inp_faddr.s_addr != INADDR_ANY) {
+ if (inp->inp_faddr.s_addr != ip->ip_src.s_addr ||
+ inp->inp_laddr.s_addr != ip->ip_dst.s_addr ||
+ inp->inp_fport != th->th_sport ||
+ inp->inp_lport != th->th_dport) {
+ os_log_error(OS_LOG_DEFAULT, "%s 5-tuple does not match: %u:%u %u:%u\n",
+ __func__,
+ ntohs(inp->inp_fport), ntohs(th->th_sport),
+ ntohs(inp->inp_lport), ntohs(th->th_dport));
+ if (findpcb_iterated) {
+ goto drop;
+ }
+ findpcb_iterated = true;
+ socket_unlock(so, 1);
+ inp = NULL;
+ goto findpcb;
+ }
+ } else if (isipv6 && !IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_faddr)) {
+ if (!IN6_ARE_ADDR_EQUAL(&inp->in6p_faddr, &ip6->ip6_src) ||
+ !IN6_ARE_ADDR_EQUAL(&inp->in6p_laddr, &ip6->ip6_dst) ||
+ inp->inp_fport != th->th_sport ||
+ inp->inp_lport != th->th_dport) {
+ os_log_error(OS_LOG_DEFAULT, "%s 5-tuple does not match: %u:%u %u:%u\n",
+ __func__,
+ ntohs(inp->inp_fport), ntohs(th->th_sport),
+ ntohs(inp->inp_lport), ntohs(th->th_dport));
+ if (findpcb_iterated) {
+ goto drop;
+ }
+ findpcb_iterated = true;
+ socket_unlock(so, 1);
+ inp = NULL;
+ goto findpcb;
}
}
- /*
- * T/TCP mechanism
- * If T/TCP was negotiated and the segment doesn't have CC,
- * or if its CC is wrong then drop the segment.
- * RST segments do not have to comply with this.
- */
- if ((tp->t_flags & (TF_REQ_CC|TF_RCVD_CC)) == (TF_REQ_CC|TF_RCVD_CC) &&
- ((to.to_flag & TOF_CC) == 0 || tp->cc_recv != to.to_cc))
- goto dropafterack;
-
- /*
- * In the SYN-RECEIVED state, validate that the packet belongs to
- * this connection before trimming the data to fit the receive
- * window. Check the sequence number versus IRS since we know
- * the sequence numbers haven't wrapped. This is a partial fix
- * for the "LAND" DoS attack.
- */
- if (tp->t_state == TCPS_SYN_RECEIVED && SEQ_LT(th->th_seq, tp->irs))
+ tp = intotcpcb(inp);
+ if (tp == NULL) {
+ rstreason = BANDLIM_RST_CLOSEDPORT;
+ IF_TCP_STATINC(ifp, noconnlist);
+ TCP_LOG_DROP_PKT(TCP_LOG_HDR, th, ifp, "tp is NULL");
goto dropwithreset;
+ }
- todrop = tp->rcv_nxt - th->th_seq;
- if (todrop > 0) {
- if (thflags & TH_SYN) {
- thflags &= ~TH_SYN;
- th->th_seq++;
- if (th->th_urp > 1)
- th->th_urp--;
- else
- thflags &= ~TH_URG;
- todrop--;
+ TCP_LOG_TH_FLAGS(TCP_LOG_HDR, th, tp, false, ifp);
+
+ if (tp->t_state == TCPS_CLOSED) {
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "tp state TCPS_CLOSED");
+ goto drop;
+ }
+
+#if NECP
+ if (so->so_state & SS_ISCONNECTED) {
+ // Connected TCP sockets have a fully-bound local and remote,
+ // so the policy check doesn't need to override addresses
+ if (!necp_socket_is_allowed_to_send_recv(inp, ifp, NULL, NULL, NULL)) {
+ TCP_LOG_DROP_NECP(TCP_LOG_HDR, th, intotcpcb(inp), false);
+ IF_TCP_STATINC(ifp, badformat);
+ goto drop;
}
+ } else {
/*
- * Following if statement from Stevens, vol. 2, p. 960.
+ * If the proc_uuid_policy table has been updated since the last use
+ * of the listening socket (i.e., the proc_uuid_policy_table_gencount
+ * has been updated), the flags in the socket may be out of date.
+ * If INP2_WANT_APP_POLICY is stale, inbound packets may
+ * be dropped by NECP if the socket should now match a per-app
+ * exception policy.
+ * In order to avoid this refresh the proc_uuid_policy state to
+ * potentially recalculate the socket's flags before checking
+ * with NECP.
*/
- if (todrop > tilen
- || (todrop == tilen && (thflags & TH_FIN) == 0)) {
- /*
- * Any valid FIN must be to the left of the window.
- * At this point the FIN must be a duplicate or out
- * of sequence; drop it.
- */
- thflags &= ~TH_FIN;
-
- /*
- * Send an ACK to resynchronize and drop any data.
- * But keep on processing for RST or ACK.
- */
- tp->t_flags |= TF_ACKNOW;
- todrop = tilen;
- tcpstat.tcps_rcvduppack++;
- tcpstat.tcps_rcvdupbyte += todrop;
- } else {
- tcpstat.tcps_rcvpartduppack++;
- tcpstat.tcps_rcvpartdupbyte += todrop;
- }
- m_adj(m, todrop);
- th->th_seq += todrop;
- tilen -= todrop;
- if (th->th_urp > todrop)
- th->th_urp -= todrop;
- else {
- thflags &= ~TH_URG;
- th->th_urp = 0;
+ (void) inp_update_policy(inp);
+#if INET6
+ if (isipv6) {
+ if (!necp_socket_is_allowed_to_send_recv_v6(inp,
+ th->th_dport, th->th_sport, &ip6->ip6_dst,
+ &ip6->ip6_src, ifp, NULL, NULL, NULL)) {
+ TCP_LOG_DROP_NECP(TCP_LOG_HDR, th, intotcpcb(inp), false);
+ IF_TCP_STATINC(ifp, badformat);
+ goto drop;
+ }
+ } else
+#endif
+ {
+ if (!necp_socket_is_allowed_to_send_recv_v4(inp,
+ th->th_dport, th->th_sport, &ip->ip_dst, &ip->ip_src,
+ ifp, NULL, NULL, NULL)) {
+ TCP_LOG_DROP_NECP(TCP_LOG_HDR, th, intotcpcb(inp), false);
+ IF_TCP_STATINC(ifp, badformat);
+ goto drop;
+ }
}
}
+#endif /* NECP */
- /*
- * If new data are received on a connection after the
- * user processes are gone, then RST the other end.
- */
- if ((so->so_state & SS_NOFDREF) &&
- tp->t_state > TCPS_CLOSE_WAIT && tilen) {
- tp = tcp_close(tp);
- tcpstat.tcps_rcvafterclose++;
- goto dropwithreset;
+ prev_t_state = tp->t_state;
+
+ /* If none of the FIN|SYN|RST|ACK flag is set, drop */
+ if (tcp_do_rfc5961 && (thflags & TH_ACCEPT) == 0) {
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "rfc5961 TH_ACCEPT == 0");
+ goto drop;
}
- /*
- * If segment ends after window, drop trailing data
- * (and PUSH and FIN); if nothing left, just ACK.
- */
- todrop = (th->th_seq+tilen) - (tp->rcv_nxt+tp->rcv_wnd);
- if (todrop > 0) {
- tcpstat.tcps_rcvpackafterwin++;
- if (todrop >= tilen) {
- tcpstat.tcps_rcvbyteafterwin += tilen;
- /*
- * If a new connection request is received
- * while in TIME_WAIT, drop the old connection
- * and start over if the sequence numbers
- * are above the previous ones.
+ /* Unscale the window into a 32-bit value. */
+ if ((thflags & TH_SYN) == 0) {
+ tiwin = th->th_win << tp->snd_scale;
+ } else {
+ tiwin = th->th_win;
+ }
+
+
+#if CONFIG_MACF_NET
+ if (mac_inpcb_check_deliver(inp, m, AF_INET, SOCK_STREAM)) {
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "mac_inpcb_check_deliver failed");
+ goto drop;
+ }
+#endif
+
+ /* Avoid processing packets while closing a listen socket */
+ if (tp->t_state == TCPS_LISTEN &&
+ (so->so_options & SO_ACCEPTCONN) == 0) {
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "closing a listening socket");
+ goto drop;
+ }
+
+ if (so->so_options & (SO_DEBUG | SO_ACCEPTCONN)) {
+#if TCPDEBUG
+ if (so->so_options & SO_DEBUG) {
+ ostate = tp->t_state;
+#if INET6
+ if (isipv6) {
+ bcopy((char *)ip6, (char *)tcp_saveipgen,
+ sizeof(*ip6));
+ } else
+#endif /* INET6 */
+ bcopy((char *)ip, (char *)tcp_saveipgen, sizeof(*ip));
+ tcp_savetcp = *th;
+ }
+#endif
+ if (so->so_options & SO_ACCEPTCONN) {
+ struct tcpcb *tp0 = tp;
+ struct socket *so2;
+ struct socket *oso;
+ struct sockaddr_storage from;
+ struct sockaddr_storage to2;
+#if INET6
+ struct inpcb *oinp = sotoinpcb(so);
+#endif /* INET6 */
+ struct ifnet *head_ifscope;
+ unsigned int head_nocell, head_recvanyif,
+ head_noexpensive, head_awdl_unrestricted,
+ head_intcoproc_allowed, head_external_port,
+ head_noconstrained;
+
+ /* Get listener's bound-to-interface, if any */
+ head_ifscope = (inp->inp_flags & INP_BOUND_IF) ?
+ inp->inp_boundifp : NULL;
+ /* Get listener's no-cellular information, if any */
+ head_nocell = INP_NO_CELLULAR(inp);
+ /* Get listener's recv-any-interface, if any */
+ head_recvanyif = (inp->inp_flags & INP_RECV_ANYIF);
+ /* Get listener's no-expensive information, if any */
+ head_noexpensive = INP_NO_EXPENSIVE(inp);
+ head_noconstrained = INP_NO_CONSTRAINED(inp);
+ head_awdl_unrestricted = INP_AWDL_UNRESTRICTED(inp);
+ head_intcoproc_allowed = INP_INTCOPROC_ALLOWED(inp);
+ head_external_port = (inp->inp_flags2 & INP2_EXTERNAL_PORT);
+
+ /*
+ * If the state is LISTEN then ignore segment if it contains an RST.
+ * If the segment contains an ACK then it is bad and send a RST.
+ * If it does not contain a SYN then it is not interesting; drop it.
+ * If it is from this socket, drop it, it must be forged.
*/
- if (thflags & TH_SYN &&
- tp->t_state == TCPS_TIME_WAIT &&
- SEQ_GT(th->th_seq, tp->rcv_nxt)) {
- iss = tp->rcv_nxt + TCP_ISSINCR;
- tp = tcp_close(tp);
- goto findpcb;
+ if ((thflags & (TH_RST | TH_ACK | TH_SYN)) != TH_SYN) {
+ IF_TCP_STATINC(ifp, listbadsyn);
+
+ if (thflags & TH_RST) {
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "SYN with RST");
+ goto drop;
+ }
+ if (thflags & TH_ACK) {
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "SYN with ACK");
+ tp = NULL;
+ tcpstat.tcps_badsyn++;
+ rstreason = BANDLIM_RST_OPENPORT;
+ goto dropwithreset;
+ }
+
+ /* We come here if there is no SYN set */
+ tcpstat.tcps_badsyn++;
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "bad SYN");
+ goto drop;
+ }
+ KERNEL_DEBUG(DBG_FNC_TCP_NEWCONN | DBG_FUNC_START, 0, 0, 0, 0, 0);
+ if (th->th_dport == th->th_sport) {
+#if INET6
+ if (isipv6) {
+ if (IN6_ARE_ADDR_EQUAL(&ip6->ip6_dst,
+ &ip6->ip6_src)) {
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "bad tuple same port");
+ goto drop;
+ }
+ } else
+#endif /* INET6 */
+ if (ip->ip_dst.s_addr == ip->ip_src.s_addr) {
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "bad tuple same IPv4 address");
+ goto drop;
+ }
}
/*
- * If window is closed can only take segments at
- * window edge, and have to drop data and PUSH from
- * incoming segments. Continue processing, but
- * remember to ack. Otherwise, drop segment
- * and ack.
+ * RFC1122 4.2.3.10, p. 104: discard bcast/mcast SYN
+ * in_broadcast() should never return true on a received
+ * packet with M_BCAST not set.
+ *
+ * Packets with a multicast source address should also
+ * be discarded.
*/
- if (tp->rcv_wnd == 0 && th->th_seq == tp->rcv_nxt) {
- tp->t_flags |= TF_ACKNOW;
- tcpstat.tcps_rcvwinprobe++;
+ if (m->m_flags & (M_BCAST | M_MCAST)) {
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "mbuf M_BCAST | M_MCAST");
+ goto drop;
+ }
+#if INET6
+ if (isipv6) {
+ if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
+ IN6_IS_ADDR_MULTICAST(&ip6->ip6_src)) {
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "IN6_IS_ADDR_MULTICAST");
+ goto drop;
+ }
} else
- goto dropafterack;
- } else
- tcpstat.tcps_rcvbyteafterwin += todrop;
- m_adj(m, -todrop);
- tilen -= todrop;
- thflags &= ~(TH_PUSH|TH_FIN);
+#endif
+ if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) ||
+ IN_MULTICAST(ntohl(ip->ip_src.s_addr)) ||
+ ip->ip_src.s_addr == htonl(INADDR_BROADCAST) ||
+ in_broadcast(ip->ip_dst, m->m_pkthdr.rcvif)) {
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "multicast or broadcast address");
+ goto drop;
+ }
+
+
+#if INET6
+ /*
+ * If deprecated address is forbidden,
+ * we do not accept SYN to deprecated interface
+ * address to prevent any new inbound connection from
+ * getting established.
+ * When we do not accept SYN, we send a TCP RST,
+ * with deprecated source address (instead of dropping
+ * it). We compromise it as it is much better for peer
+ * to send a RST, and RST will be the final packet
+ * for the exchange.
+ *
+ * If we do not forbid deprecated addresses, we accept
+ * the SYN packet. RFC 4862 forbids dropping SYN in
+ * this case.
+ */
+ if (isipv6 && !ip6_use_deprecated) {
+ uint32_t ia6_flags;
+
+ if (ip6_getdstifaddr_info(m, NULL,
+ &ia6_flags) == 0) {
+ if (ia6_flags & IN6_IFF_DEPRECATED) {
+ tp = NULL;
+ rstreason = BANDLIM_RST_OPENPORT;
+ IF_TCP_STATINC(ifp, deprecate6);
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "deprecated IPv6 address");
+ goto dropwithreset;
+ }
+ }
+ }
+#endif
+ if (so->so_filt || check_cfil) {
+#if INET6
+ if (isipv6) {
+ struct sockaddr_in6 *sin6 = (struct sockaddr_in6*)&from;
+
+ sin6->sin6_len = sizeof(*sin6);
+ sin6->sin6_family = AF_INET6;
+ sin6->sin6_port = th->th_sport;
+ sin6->sin6_flowinfo = 0;
+ sin6->sin6_addr = ip6->ip6_src;
+ sin6->sin6_scope_id = 0;
+
+ sin6 = (struct sockaddr_in6*)&to2;
+
+ sin6->sin6_len = sizeof(struct sockaddr_in6);
+ sin6->sin6_family = AF_INET6;
+ sin6->sin6_port = th->th_dport;
+ sin6->sin6_flowinfo = 0;
+ sin6->sin6_addr = ip6->ip6_dst;
+ sin6->sin6_scope_id = 0;
+ } else
+#endif
+ {
+ struct sockaddr_in *sin = (struct sockaddr_in*)&from;
+
+ sin->sin_len = sizeof(*sin);
+ sin->sin_family = AF_INET;
+ sin->sin_port = th->th_sport;
+ sin->sin_addr = ip->ip_src;
+
+ sin = (struct sockaddr_in*)&to2;
+
+ sin->sin_len = sizeof(struct sockaddr_in);
+ sin->sin_family = AF_INET;
+ sin->sin_port = th->th_dport;
+ sin->sin_addr = ip->ip_dst;
+ }
+ }
+
+ if (so->so_filt) {
+ so2 = sonewconn(so, 0, (struct sockaddr*)&from);
+ } else {
+ so2 = sonewconn(so, 0, NULL);
+ }
+ if (so2 == 0) {
+ tcpstat.tcps_listendrop++;
+ if (tcp_dropdropablreq(so)) {
+ if (so->so_filt) {
+ so2 = sonewconn(so, 0, (struct sockaddr*)&from);
+ } else {
+ so2 = sonewconn(so, 0, NULL);
+ }
+ }
+ if (!so2) {
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, " listen drop");
+ goto drop;
+ }
+ }
+
+ /* Point "inp" and "tp" in tandem to new socket */
+ inp = (struct inpcb *)so2->so_pcb;
+ tp = intotcpcb(inp);
+
+ oso = so;
+ socket_unlock(so, 0); /* Unlock but keep a reference on listener for now */
+
+ so = so2;
+ socket_lock(so, 1);
+ /*
+ * Mark socket as temporary until we're
+ * committed to keeping it. The code at
+ * ``drop'' and ``dropwithreset'' check the
+ * flag dropsocket to see if the temporary
+ * socket created here should be discarded.
+ * We mark the socket as discardable until
+ * we're committed to it below in TCPS_LISTEN.
+ * There are some error conditions in which we
+ * have to drop the temporary socket.
+ */
+ dropsocket++;
+ /*
+ * Inherit INP_BOUND_IF from listener; testing if
+ * head_ifscope is non-NULL is sufficient, since it
+ * can only be set to a non-zero value earlier if
+ * the listener has such a flag set.
+ */
+ if (head_ifscope != NULL) {
+ inp->inp_flags |= INP_BOUND_IF;
+ inp->inp_boundifp = head_ifscope;
+ } else {
+ inp->inp_flags &= ~INP_BOUND_IF;
+ }
+ /*
+ * Inherit restrictions from listener.
+ */
+ if (head_nocell) {
+ inp_set_nocellular(inp);
+ }
+ if (head_noexpensive) {
+ inp_set_noexpensive(inp);
+ }
+ if (head_noconstrained) {
+ inp_set_noconstrained(inp);
+ }
+ if (head_awdl_unrestricted) {
+ inp_set_awdl_unrestricted(inp);
+ }
+ if (head_intcoproc_allowed) {
+ inp_set_intcoproc_allowed(inp);
+ }
+ /*
+ * Inherit {IN,IN6}_RECV_ANYIF from listener.
+ */
+ if (head_recvanyif) {
+ inp->inp_flags |= INP_RECV_ANYIF;
+ } else {
+ inp->inp_flags &= ~INP_RECV_ANYIF;
+ }
+
+ if (head_external_port) {
+ inp->inp_flags2 |= INP2_EXTERNAL_PORT;
+ }
+#if INET6
+ if (isipv6) {
+ inp->in6p_laddr = ip6->ip6_dst;
+ } else {
+ inp->inp_vflag &= ~INP_IPV6;
+ inp->inp_vflag |= INP_IPV4;
+#endif /* INET6 */
+ inp->inp_laddr = ip->ip_dst;
+#if INET6
+ }
+#endif /* INET6 */
+ inp->inp_lport = th->th_dport;
+ if (in_pcbinshash(inp, 0) != 0) {
+ /*
+ * Undo the assignments above if we failed to
+ * put the PCB on the hash lists.
+ */
+#if INET6
+ if (isipv6) {
+ inp->in6p_laddr = in6addr_any;
+ } else
+#endif /* INET6 */
+ inp->inp_laddr.s_addr = INADDR_ANY;
+ inp->inp_lport = 0;
+ socket_lock(oso, 0); /* release ref on parent */
+ socket_unlock(oso, 1);
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, " in_pcbinshash failed");
+ goto drop;
+ }
+#if INET6
+ if (isipv6) {
+ /*
+ * Inherit socket options from the listening
+ * socket.
+ * Note that in6p_inputopts are not (even
+ * should not be) copied, since it stores
+ * previously received options and is used to
+ * detect if each new option is different than
+ * the previous one and hence should be passed
+ * to a user.
+ * If we copied in6p_inputopts, a user would
+ * not be able to receive options just after
+ * calling the accept system call.
+ */
+ inp->inp_flags |=
+ oinp->inp_flags & INP_CONTROLOPTS;
+ if (oinp->in6p_outputopts) {
+ inp->in6p_outputopts =
+ ip6_copypktopts(oinp->in6p_outputopts,
+ M_NOWAIT);
+ }
+ } else
+#endif /* INET6 */
+ {
+ inp->inp_options = ip_srcroute();
+ inp->inp_ip_tos = oinp->inp_ip_tos;
+ }
+ socket_lock(oso, 0);
+#if IPSEC
+ /* copy old policy into new socket's */
+ if (sotoinpcb(oso)->inp_sp) {
+ int error = 0;
+ /* Is it a security hole here to silently fail to copy the policy? */
+ if (inp->inp_sp != NULL) {
+ error = ipsec_init_policy(so, &inp->inp_sp);
+ }
+ if (error != 0 || ipsec_copy_policy(sotoinpcb(oso)->inp_sp, inp->inp_sp)) {
+ printf("tcp_input: could not copy policy\n");
+ }
+ }
+#endif
+ /* inherit states from the listener */
+ DTRACE_TCP4(state__change, void, NULL, struct inpcb *, inp,
+ struct tcpcb *, tp, int32_t, TCPS_LISTEN);
+ tp->t_state = TCPS_LISTEN;
+ tp->t_flags |= tp0->t_flags & (TF_NOPUSH | TF_NOOPT | TF_NODELAY);
+ tp->t_flagsext |= (tp0->t_flagsext & (TF_RXTFINDROP | TF_NOTIMEWAIT | TF_FASTOPEN));
+ tp->t_keepinit = tp0->t_keepinit;
+ tp->t_keepcnt = tp0->t_keepcnt;
+ tp->t_keepintvl = tp0->t_keepintvl;
+ tp->t_adaptive_wtimo = tp0->t_adaptive_wtimo;
+ tp->t_adaptive_rtimo = tp0->t_adaptive_rtimo;
+ tp->t_inpcb->inp_ip_ttl = tp0->t_inpcb->inp_ip_ttl;
+ if ((so->so_flags & SOF_NOTSENT_LOWAT) != 0) {
+ tp->t_notsent_lowat = tp0->t_notsent_lowat;
+ }
+ tp->t_inpcb->inp_flags2 |=
+ tp0->t_inpcb->inp_flags2 & INP2_KEEPALIVE_OFFLOAD;
+
+ /* now drop the reference on the listener */
+ socket_unlock(oso, 1);
+
+ tcp_set_max_rwinscale(tp, so, ifp);
+
+#if CONTENT_FILTER
+ if (check_cfil) {
+ int error = cfil_sock_attach(so2, (struct sockaddr*)&to2, (struct sockaddr*)&from,
+ CFS_CONNECTION_DIR_IN);
+ if (error != 0) {
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, " cfil_sock_attach failed");
+ goto drop;
+ }
+ }
+#endif /* CONTENT_FILTER */
+
+ KERNEL_DEBUG(DBG_FNC_TCP_NEWCONN | DBG_FUNC_END, 0, 0, 0, 0, 0);
+ }
+ }
+ socket_lock_assert_owned(so);
+
+ if (net_mpklog_enabled && (m->m_pkthdr.rcvif->if_xflags & IFXF_MPK_LOG)) {
+ MPKL_TCP_INPUT(tcp_mpkl_log_object,
+ ntohs(tp->t_inpcb->inp_lport), ntohs(tp->t_inpcb->inp_fport),
+ th->th_seq, th->th_ack, tlen, thflags,
+ so->last_pid, so->so_log_seqn++);
+ }
+
+ if (tp->t_state == TCPS_ESTABLISHED && tlen > 0) {
+ /*
+ * Evaluate the rate of arrival of packets to see if the
+ * receiver can reduce the ack traffic. The algorithm to
+ * stretch acks will be enabled if the connection meets
+ * certain criteria defined in tcp_stretch_ack_enable function.
+ */
+ if ((tp->t_flagsext & TF_RCVUNACK_WAITSS) != 0) {
+ TCP_INC_VAR(tp->rcv_waitforss, nlropkts);
+ }
+ if (tcp_stretch_ack_enable(tp, thflags)) {
+ tp->t_flags |= TF_STRETCHACK;
+ tp->t_flagsext &= ~(TF_RCVUNACK_WAITSS);
+ tp->rcv_waitforss = 0;
+ } else {
+ tp->t_flags &= ~(TF_STRETCHACK);
+ }
+ if (TSTMP_GT(tp->rcv_unackwin - (tcp_rcvunackwin >> 1), tcp_now)) {
+ tp->rcv_by_unackhalfwin += (tlen + off);
+ tp->rcv_by_unackwin += (tlen + off);
+ } else {
+ tp->rcv_unackwin = tcp_now + tcp_rcvunackwin;
+ tp->rcv_by_unackwin = tp->rcv_by_unackhalfwin + tlen + off;
+ tp->rcv_by_unackhalfwin = tlen + off;
+ }
}
/*
- * If last ACK falls within this segment's sequence numbers,
- * record its timestamp.
- * NOTE that the test is modified according to the latest
- * proposal of the tcplw@cray.com list (Braden 1993/04/26).
+ * Keep track of how many bytes were received in the LRO packet
*/
- if ((to.to_flag & TOF_TS) != 0 &&
- SEQ_LEQ(th->th_seq, tp->last_ack_sent)) {
- tp->ts_recent_age = tcp_now;
- tp->ts_recent = to.to_tsval;
+ if ((pktf_sw_lro_pkt) && (nlropkts > 2)) {
+ tp->t_lropktlen += tlen;
}
-
/*
- * If a SYN is in the window, then this is an
- * error and we send an RST and drop the connection.
+ * Explicit Congestion Notification - Flag that we need to send ECT if
+ * + The IP Congestion experienced flag was set.
+ * + Socket is in established state
+ * + We negotiated ECN in the TCP setup
+ * + This isn't a pure ack (tlen > 0)
+ * + The data is in the valid window
+ *
+ * TE_SENDECE will be cleared when we receive a packet with TH_CWR set.
*/
- if (thflags & TH_SYN) {
- tp = tcp_drop(tp, ECONNRESET);
- postevent(so, 0, EV_RESET);
- goto dropwithreset;
+ if (ip_ecn == IPTOS_ECN_CE && tp->t_state == TCPS_ESTABLISHED &&
+ TCP_ECN_ENABLED(tp) && tlen > 0 &&
+ SEQ_GEQ(th->th_seq, tp->last_ack_sent) &&
+ SEQ_LT(th->th_seq, tp->last_ack_sent + tp->rcv_wnd)) {
+ tp->t_ecn_recv_ce++;
+ tcpstat.tcps_ecn_recv_ce++;
+ INP_INC_IFNET_STAT(inp, ecn_recv_ce);
+ /* Mark this connection as it received CE from network */
+ tp->ecn_flags |= TE_RECV_ECN_CE;
+ tp->ecn_flags |= TE_SENDECE;
}
/*
- * If the ACK bit is off: if in SYN-RECEIVED state or SENDSYN
- * flag is on (half-synchronized state), then queue data for
- * later processing; else drop segment and return.
+ * Clear TE_SENDECE if TH_CWR is set. This is harmless, so we don't
+ * bother doing extensive checks for state and whatnot.
*/
- if ((thflags & TH_ACK) == 0) {
- if (tp->t_state == TCPS_SYN_RECEIVED ||
- (tp->t_flags & TF_NEEDSYN))
- goto step6;
- else
- goto drop;
+ if (thflags & TH_CWR) {
+ tp->ecn_flags &= ~TE_SENDECE;
+ tp->t_ecn_recv_cwr++;
}
/*
- * Ack processing.
+ * If we received an explicit notification of congestion in
+ * ip tos ecn bits or by the CWR bit in TCP header flags, reset
+ * the ack-strteching state. We need to handle ECN notification if
+ * an ECN setup SYN was sent even once.
*/
- switch (tp->t_state) {
+ if (tp->t_state == TCPS_ESTABLISHED
+ && (tp->ecn_flags & TE_SETUPSENT)
+ && (ip_ecn == IPTOS_ECN_CE || (thflags & TH_CWR))) {
+ tcp_reset_stretch_ack(tp);
+ CLEAR_IAJ_STATE(tp);
+ }
+
+ if (ip_ecn == IPTOS_ECN_CE && tp->t_state == TCPS_ESTABLISHED &&
+ !TCP_ECN_ENABLED(tp) && !(tp->ecn_flags & TE_CEHEURI_SET)) {
+ tcpstat.tcps_ecn_fallback_ce++;
+ tcp_heuristic_ecn_aggressive(tp);
+ tp->ecn_flags |= TE_CEHEURI_SET;
+ }
+
+ if (tp->t_state == TCPS_ESTABLISHED && TCP_ECN_ENABLED(tp) &&
+ ip_ecn == IPTOS_ECN_CE && !(tp->ecn_flags & TE_CEHEURI_SET)) {
+ if (inp->inp_stat->rxpackets < ECN_MIN_CE_PROBES) {
+ tp->t_ecn_recv_ce_pkt++;
+ } else if (tp->t_ecn_recv_ce_pkt > ECN_MAX_CE_RATIO) {
+ tcpstat.tcps_ecn_fallback_ce++;
+ tcp_heuristic_ecn_aggressive(tp);
+ tp->ecn_flags |= TE_CEHEURI_SET;
+ INP_INC_IFNET_STAT(inp, ecn_fallback_ce);
+ } else {
+ /* We tracked the first ECN_MIN_CE_PROBES segments, we
+ * now know that the path is good.
+ */
+ tp->ecn_flags |= TE_CEHEURI_SET;
+ }
+ }
/*
- * In SYN_RECEIVED state, the ack ACKs our SYN, so enter
- * ESTABLISHED state and continue processing.
- * The ACK was checked above.
+ * Try to determine if we are receiving a packet after a long time.
+ * Use our own approximation of idletime to roughly measure remote
+ * end's idle time. Since slowstart is used after an idle period
+ * we want to avoid doing LRO if the remote end is not up to date
+ * on initial window support and starts with 1 or 2 packets as its IW.
*/
- case TCPS_SYN_RECEIVED:
+ if (sw_lro && (tp->t_flagsext & TF_LRO_OFFLOADED) &&
+ ((tcp_now - tp->t_rcvtime) >= (TCP_IDLETIMEOUT(tp)))) {
+ turnoff_lro = 1;
+ }
- tcpstat.tcps_connects++;
- soisconnected(so);
- current_active_connections++;
+ /* Update rcvtime as a new segment was received on the connection */
+ tp->t_rcvtime = tcp_now;
- /* Do window scaling? */
- if ((tp->t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) ==
- (TF_RCVD_SCALE|TF_REQ_SCALE)) {
- tp->snd_scale = tp->requested_s_scale;
- tp->rcv_scale = tp->request_r_scale;
+ /*
+ * Segment received on connection.
+ * Reset idle time and keep-alive timer.
+ */
+ if (TCPS_HAVEESTABLISHED(tp->t_state)) {
+ tcp_keepalive_reset(tp);
+
+ if (tp->t_mpsub) {
+ mptcp_reset_keepalive(tp);
}
- /*
- * Upon successful completion of 3-way handshake,
- * update cache.CC if it was undefined, pass any queued
- * data to the user, and advance state appropriately.
- */
- if ((taop = tcp_gettaocache(inp)) != NULL &&
- taop->tao_cc == 0)
- taop->tao_cc = tp->cc_recv;
+ }
- /*
- * Make transitions:
- * SYN-RECEIVED -> ESTABLISHED
- * SYN-RECEIVED* -> FIN-WAIT-1
- */
- if (tp->t_flags & TF_NEEDFIN) {
- tp->t_state = TCPS_FIN_WAIT_1;
- tp->t_flags &= ~TF_NEEDFIN;
- } else {
- tp->t_state = TCPS_ESTABLISHED;
- tp->t_timer[TCPT_KEEP] = tcp_keepidle;
+ /*
+ * Process options if not in LISTEN state,
+ * else do it below (after getting remote address).
+ */
+ if (tp->t_state != TCPS_LISTEN && optp) {
+ tcp_dooptions(tp, optp, optlen, th, &to);
+ }
+#if MPTCP
+ if (tp->t_state != TCPS_LISTEN && (so->so_flags & SOF_MP_SUBFLOW) &&
+ mptcp_input_preproc(tp, m, th, drop_hdrlen) != 0) {
+ tp->t_flags |= TF_ACKNOW;
+ (void) tcp_output(tp);
+ tcp_check_timer_state(tp);
+ socket_unlock(so, 1);
+ KERNEL_DEBUG(DBG_FNC_TCP_INPUT |
+ DBG_FUNC_END, 0, 0, 0, 0, 0);
+ return;
+ }
+#endif /* MPTCP */
+ if (tp->t_state == TCPS_SYN_SENT && (thflags & TH_SYN)) {
+ if (!(thflags & TH_ACK) ||
+ (SEQ_GT(th->th_ack, tp->iss) &&
+ SEQ_LEQ(th->th_ack, tp->snd_max))) {
+ tcp_finalize_options(tp, &to, ifscope);
}
- /*
- * If segment contains data or ACK, will call tcp_reass()
- * later; if not, do so now to pass queued data to user.
- */
- if (tilen == 0 && (thflags & TH_FIN) == 0)
- (void) tcp_reass(tp, (struct tcphdr *)0, 0,
- (struct mbuf *)0, isipv6);
- tp->snd_wl1 = th->th_seq - 1;
- /* fall into ... */
+ }
+#if TRAFFIC_MGT
/*
- * In ESTABLISHED state: drop duplicate ACKs; ACK out of range
- * ACKs. If the ack is in the range
- * tp->snd_una < th->th_ack <= tp->snd_max
- * then advance tp->snd_una to th->th_ack and drop
- * data from the retransmission queue. If this ACK reflects
- * more up to date window information we update our window information.
+ * Compute inter-packet arrival jitter. According to RFC 3550,
+ * inter-packet arrival jitter is defined as the difference in
+ * packet spacing at the receiver compared to the sender for a
+ * pair of packets. When two packets of maximum segment size come
+ * one after the other with consecutive sequence numbers, we
+ * consider them as packets sent together at the sender and use
+ * them as a pair to compute inter-packet arrival jitter. This
+ * metric indicates the delay induced by the network components due
+ * to queuing in edge/access routers.
*/
- case TCPS_ESTABLISHED:
- case TCPS_FIN_WAIT_1:
- case TCPS_FIN_WAIT_2:
- case TCPS_CLOSE_WAIT:
- case TCPS_CLOSING:
- case TCPS_LAST_ACK:
- case TCPS_TIME_WAIT:
+ if (tp->t_state == TCPS_ESTABLISHED &&
+ (thflags & (TH_SYN | TH_FIN | TH_RST | TH_URG | TH_ACK | TH_ECE | TH_PUSH)) == TH_ACK &&
+ ((tp->t_flags & (TF_NEEDSYN | TF_NEEDFIN)) == 0) &&
+ ((to.to_flags & TOF_TS) == 0 ||
+ TSTMP_GEQ(to.to_tsval, tp->ts_recent)) &&
+ th->th_seq == tp->rcv_nxt && LIST_EMPTY(&tp->t_segq)) {
+ int seg_size = tlen;
+ if (tp->iaj_pktcnt <= IAJ_IGNORE_PKTCNT) {
+ TCP_INC_VAR(tp->iaj_pktcnt, nlropkts);
+ }
- if (SEQ_LEQ(th->th_ack, tp->snd_una)) {
- if (tilen == 0 && tiwin == tp->snd_wnd) {
- tcpstat.tcps_rcvdupack++;
+ if (m->m_pkthdr.pkt_flags & PKTF_SW_LRO_PKT) {
+ seg_size = m->m_pkthdr.lro_pktlen;
+ }
+ if (tp->iaj_size == 0 || seg_size > tp->iaj_size ||
+ (seg_size == tp->iaj_size && tp->iaj_rcv_ts == 0)) {
+ /*
+ * State related to inter-arrival jitter is
+ * uninitialized or we are trying to find a good
+ * first packet to start computing the metric
+ */
+ update_iaj_state(tp, seg_size, 0);
+ } else {
+ if (seg_size == tp->iaj_size) {
/*
- * If we have outstanding data (other than
- * a window probe), this is a completely
- * duplicate ack (ie, window info didn't
- * change), the ack is the biggest we've
- * seen and we've seen exactly our rexmt
- * threshhold of them, assume a packet
- * has been dropped and retransmit it.
- * Kludge snd_nxt & the congestion
- * window so we send only this one
- * packet.
- *
- * We know we're losing at the current
- * window size so do congestion avoidance
- * (set ssthresh to half the current window
- * and pull our congestion window back to
- * the new ssthresh).
- *
- * Dup acks mean that packets have left the
- * network (they're now cached at the receiver)
- * so bump cwnd by the amount in the receiver
- * to keep a constant cwnd packets in the
- * network.
+ * Compute inter-arrival jitter taking
+ * this packet as the second packet
*/
- if (tp->t_timer[TCPT_REXMT] == 0 ||
- th->th_ack != tp->snd_una)
- tp->t_dupacks = 0;
- else if (++tp->t_dupacks == tcprexmtthresh) {
- tcp_seq onxt = tp->snd_nxt;
- u_int win =
- min(tp->snd_wnd, tp->snd_cwnd) / 2 /
- tp->t_maxseg;
-
- if (win < 2)
- win = 2;
- tp->snd_ssthresh = win * tp->t_maxseg;
- tp->t_timer[TCPT_REXMT] = 0;
- tp->t_rtt = 0;
- tp->snd_nxt = th->th_ack;
- tp->snd_cwnd = tp->t_maxseg;
- (void) tcp_output(tp);
- tp->snd_cwnd = tp->snd_ssthresh +
- tp->t_maxseg * tp->t_dupacks;
- if (SEQ_GT(onxt, tp->snd_nxt))
- tp->snd_nxt = onxt;
- goto drop;
- } else if (tp->t_dupacks > tcprexmtthresh) {
- tp->snd_cwnd += tp->t_maxseg;
- (void) tcp_output(tp);
- goto drop;
+ if (pktf_sw_lro_pkt) {
+ compute_iaj(tp, nlropkts,
+ m->m_pkthdr.lro_elapsed);
+ } else {
+ compute_iaj(tp, 1, 0);
}
- } else
- tp->t_dupacks = 0;
- break;
- }
- /*
- * If the congestion window was inflated to account
- * for the other side's cached packets, retract it.
- */
- if (tp->t_dupacks >= tcprexmtthresh &&
- tp->snd_cwnd > tp->snd_ssthresh)
- tp->snd_cwnd = tp->snd_ssthresh;
- tp->t_dupacks = 0;
- if (SEQ_GT(th->th_ack, tp->snd_max)) {
- tcpstat.tcps_rcvacktoomuch++;
- goto dropafterack;
+ }
+ if (seg_size < tp->iaj_size) {
+ /*
+ * There is a smaller packet in the stream.
+ * Some times the maximum size supported
+ * on a path can change if there is a new
+ * link with smaller MTU. The receiver will
+ * not know about this change. If there
+ * are too many packets smaller than
+ * iaj_size, we try to learn the iaj_size
+ * again.
+ */
+ TCP_INC_VAR(tp->iaj_small_pkt, nlropkts);
+ if (tp->iaj_small_pkt > RESET_IAJ_SIZE_THRESH) {
+ update_iaj_state(tp, seg_size, 1);
+ } else {
+ CLEAR_IAJ_STATE(tp);
+ }
+ } else {
+ update_iaj_state(tp, seg_size, 0);
+ }
}
+ } else {
+ CLEAR_IAJ_STATE(tp);
+ }
+#endif /* TRAFFIC_MGT */
+
+ /*
+ * Header prediction: check for the two common cases
+ * of a uni-directional data xfer. If the packet has
+ * no control flags, is in-sequence, the window didn't
+ * change and we're not retransmitting, it's a
+ * candidate. If the length is zero and the ack moved
+ * forward, we're the sender side of the xfer. Just
+ * free the data acked & wake any higher level process
+ * that was blocked waiting for space. If the length
+ * is non-zero and the ack didn't move, we're the
+ * receiver side. If we're getting packets in-order
+ * (the reassembly queue is empty), add the data to
+ * the socket buffer and note that we need a delayed ack.
+ * Make sure that the hidden state-flags are also off.
+ * Since we check for TCPS_ESTABLISHED above, it can only
+ * be TH_NEEDSYN.
+ */
+ if (tp->t_state == TCPS_ESTABLISHED &&
+ (thflags & (TH_SYN | TH_FIN | TH_RST | TH_URG | TH_ACK | TH_ECE | TH_CWR)) == TH_ACK &&
+ ((tp->t_flags & (TF_NEEDSYN | TF_NEEDFIN)) == 0) &&
+ ((to.to_flags & TOF_TS) == 0 ||
+ TSTMP_GEQ(to.to_tsval, tp->ts_recent)) &&
+ th->th_seq == tp->rcv_nxt &&
+ tiwin && tiwin == tp->snd_wnd &&
+ tp->snd_nxt == tp->snd_max) {
/*
- * If we reach this point, ACK is not a duplicate,
- * i.e., it ACKs something we sent.
+ * If last ACK falls within this segment's sequence numbers,
+ * record the timestamp.
+ * NOTE that the test is modified according to the latest
+ * proposal of the tcplw@cray.com list (Braden 1993/04/26).
*/
- if (tp->t_flags & TF_NEEDSYN) {
- /*
- * T/TCP: Connection was half-synchronized, and our
- * SYN has been ACK'd (so connection is now fully
- * synchronized). Go to non-starred state,
- * increment snd_una for ACK of SYN, and check if
- * we can do window scaling.
- */
- tp->t_flags &= ~TF_NEEDSYN;
- tp->snd_una++;
- /* Do window scaling? */
- if ((tp->t_flags & (TF_RCVD_SCALE|TF_REQ_SCALE)) ==
- (TF_RCVD_SCALE|TF_REQ_SCALE)) {
- tp->snd_scale = tp->requested_s_scale;
- tp->rcv_scale = tp->request_r_scale;
- }
+ if ((to.to_flags & TOF_TS) != 0 &&
+ SEQ_LEQ(th->th_seq, tp->last_ack_sent)) {
+ tp->ts_recent_age = tcp_now;
+ tp->ts_recent = to.to_tsval;
}
-process_ACK:
- acked = th->th_ack - tp->snd_una;
- tcpstat.tcps_rcvackpack++;
- tcpstat.tcps_rcvackbyte += acked;
+ if (tlen == 0) {
+ if (SEQ_GT(th->th_ack, tp->snd_una) &&
+ SEQ_LEQ(th->th_ack, tp->snd_max) &&
+ tp->snd_cwnd >= tp->snd_ssthresh &&
+ (!IN_FASTRECOVERY(tp) &&
+ ((!(SACK_ENABLED(tp)) &&
+ tp->t_dupacks < tp->t_rexmtthresh) ||
+ (SACK_ENABLED(tp) && to.to_nsacks == 0 &&
+ TAILQ_EMPTY(&tp->snd_holes))))) {
+ /*
+ * this is a pure ack for outstanding data.
+ */
+ ++tcpstat.tcps_predack;
- /*
- * If we have a timestamp reply, update smoothed
- * round trip time. If no timestamp is present but
- * transmit timer is running and timed sequence
- * number was acked, update smoothed round trip time.
- * Since we now have an rtt measurement, cancel the
- * timer backoff (cf., Phil Karn's retransmit alg.).
- * Recompute the initial retransmit timer.
- */
- if (to.to_flag & TOF_TS)
- tcp_xmit_timer(tp, tcp_now - to.to_tsecr + 1);
- else if (tp->t_rtt && SEQ_GT(th->th_ack, tp->t_rtseq))
- tcp_xmit_timer(tp,tp->t_rtt);
+ tcp_bad_rexmt_check(tp, th, &to);
- /*
- * If all outstanding data is acked, stop retransmit
- * timer and remember to restart (more output or persist).
- * If there is more data to be acked, restart retransmit
- * timer, using current (possibly backed-off) value.
- */
- if (th->th_ack == tp->snd_max) {
- tp->t_timer[TCPT_REXMT] = 0;
- needoutput = 1;
- } else if (tp->t_timer[TCPT_PERSIST] == 0)
- tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;
+ /* Recalculate the RTT */
+ tcp_compute_rtt(tp, &to, th);
- /*
- * If no data (only SYN) was ACK'd,
- * skip rest of ACK processing.
- */
- if (acked == 0)
- goto step6;
+ VERIFY(SEQ_GEQ(th->th_ack, tp->snd_una));
+ acked = BYTES_ACKED(th, tp);
+ tcpstat.tcps_rcvackpack++;
+ tcpstat.tcps_rcvackbyte += acked;
- /*
- * When new data is acked, open the congestion window.
- * If the window gives us less than ssthresh packets
- * in flight, open exponentially (maxseg per packet).
- * Otherwise open linearly: maxseg per window
- * (maxseg^2 / cwnd per packet).
- */
- {
- register u_int cw = tp->snd_cwnd;
- register u_int incr = tp->t_maxseg;
+ /*
+ * Handle an ack that is in sequence during
+ * congestion avoidance phase. The
+ * calculations in this function
+ * assume that snd_una is not updated yet.
+ */
+ if (CC_ALGO(tp)->congestion_avd != NULL) {
+ CC_ALGO(tp)->congestion_avd(tp, th);
+ }
+ tcp_ccdbg_trace(tp, th, TCP_CC_INSEQ_ACK_RCVD);
+ sbdrop(&so->so_snd, acked);
+ if (so->so_flags & SOF_ENABLE_MSGS) {
+ VERIFY(acked <= so->so_msg_state->msg_serial_bytes);
+ so->so_msg_state->msg_serial_bytes -= acked;
+ }
+ tcp_sbsnd_trim(&so->so_snd);
- if (cw > tp->snd_ssthresh)
- incr = incr * incr / cw;
- tp->snd_cwnd = min(cw + incr, TCP_MAXWIN<<tp->snd_scale);
- }
- if (acked > so->so_snd.sb_cc) {
- tp->snd_wnd -= so->so_snd.sb_cc;
- sbdrop(&so->so_snd, (int)so->so_snd.sb_cc);
- ourfinisacked = 1;
- } else {
- sbdrop(&so->so_snd, acked);
- tp->snd_wnd -= acked;
- ourfinisacked = 0;
- }
- need_sowwakeup++;
- tp->snd_una = th->th_ack;
- if (SEQ_LT(tp->snd_nxt, tp->snd_una))
- tp->snd_nxt = tp->snd_una;
+ if (SEQ_GT(tp->snd_una, tp->snd_recover) &&
+ SEQ_LEQ(th->th_ack, tp->snd_recover)) {
+ tp->snd_recover = th->th_ack - 1;
+ }
+ tp->snd_una = th->th_ack;
- switch (tp->t_state) {
+ TCP_RESET_REXMT_STATE(tp);
- /*
- * In FIN_WAIT_1 STATE in addition to the processing
- * for the ESTABLISHED state if our FIN is now acknowledged
- * then enter FIN_WAIT_2.
- */
- case TCPS_FIN_WAIT_1:
- if (ourfinisacked) {
/*
- * If we can't receive any more
- * data, then closing user can proceed.
- * Starting the timer is contrary to the
- * specification, but if we don't get a FIN
- * we'll hang forever.
+ * pull snd_wl2 up to prevent seq wrap relative
+ * to th_ack.
*/
- if (so->so_state & SS_CANTRCVMORE) {
- soisdisconnected(so);
- tp->t_timer[TCPT_2MSL] = tcp_maxidle;
+ tp->snd_wl2 = th->th_ack;
+
+ if (tp->t_dupacks > 0) {
+ tp->t_dupacks = 0;
+ tp->t_rexmtthresh = tcprexmtthresh;
}
- add_to_time_wait(tp);
- current_active_connections--;
- tp->t_state = TCPS_FIN_WAIT_2;
+
+ m_freem(m);
+
+ /*
+ * If all outstanding data are acked, stop
+ * retransmit timer, otherwise restart timer
+ * using current (possibly backed-off) value.
+ * If process is waiting for space,
+ * wakeup/selwakeup/signal. If data
+ * are ready to send, let tcp_output
+ * decide between more output or persist.
+ */
+ if (tp->snd_una == tp->snd_max) {
+ tp->t_timer[TCPT_REXMT] = 0;
+ tp->t_timer[TCPT_PTO] = 0;
+ } else if (tp->t_timer[TCPT_PERSIST] == 0) {
+ tp->t_timer[TCPT_REXMT] =
+ OFFSET_FROM_START(tp,
+ tp->t_rxtcur);
+ }
+ if (!SLIST_EMPTY(&tp->t_rxt_segments) &&
+ !TCP_DSACK_SEQ_IN_WINDOW(tp,
+ tp->t_dsack_lastuna, tp->snd_una)) {
+ tcp_rxtseg_clean(tp);
+ }
+
+ if ((tp->t_flagsext & TF_MEASURESNDBW) != 0 &&
+ tp->t_bwmeas != NULL) {
+ tcp_bwmeas_check(tp);
+ }
+
+ write_wakeup = 1;
+ if (!SLIST_EMPTY(&tp->t_notify_ack)) {
+ tcp_notify_acknowledgement(tp, so);
+ }
+
+ if ((so->so_snd.sb_cc) || (tp->t_flags & TF_ACKNOW)) {
+ (void) tcp_output(tp);
+ }
+
+ tcp_tfo_rcv_ack(tp, th);
+
+ tcp_check_timer_state(tp);
+
+ tcp_handle_wakeup(so, read_wakeup, write_wakeup);
+
+ socket_unlock(so, 1);
+ KERNEL_DEBUG(DBG_FNC_TCP_INPUT | DBG_FUNC_END, 0, 0, 0, 0, 0);
+ return;
}
- break;
+ } else if (th->th_ack == tp->snd_una &&
+ LIST_EMPTY(&tp->t_segq) &&
+ tlen <= tcp_sbspace(tp)) {
+ /*
+ * this is a pure, in-sequence data packet
+ * with nothing on the reassembly queue and
+ * we have enough buffer space to take it.
+ */
+
+ /*
+ * If this is a connection in steady state, start
+ * coalescing packets belonging to this flow.
+ */
+ if (turnoff_lro) {
+ tcp_lro_remove_state(tp->t_inpcb->inp_laddr,
+ tp->t_inpcb->inp_faddr,
+ tp->t_inpcb->inp_lport,
+ tp->t_inpcb->inp_fport);
+ tp->t_flagsext &= ~TF_LRO_OFFLOADED;
+ tp->t_idleat = tp->rcv_nxt;
+ } else if (sw_lro && !pktf_sw_lro_pkt && !isipv6 &&
+ (so->so_flags & SOF_USELRO) &&
+ !IFNET_IS_CELLULAR(m->m_pkthdr.rcvif) &&
+ (m->m_pkthdr.rcvif->if_type != IFT_LOOP) &&
+ ((th->th_seq - tp->irs) >
+ (tp->t_maxseg << lro_start)) &&
+ ((tp->t_idleat == 0) || ((th->th_seq -
+ tp->t_idleat) > (tp->t_maxseg << lro_start)))) {
+ tp->t_flagsext |= TF_LRO_OFFLOADED;
+ tcp_start_coalescing(ip, th, tlen);
+ tp->t_idleat = 0;
+ }
+
+ /* Clean receiver SACK report if present */
+ if (SACK_ENABLED(tp) && tp->rcv_numsacks) {
+ tcp_clean_sackreport(tp);
+ }
+ ++tcpstat.tcps_preddat;
+ tp->rcv_nxt += tlen;
+ /*
+ * Pull snd_wl1 up to prevent seq wrap relative to
+ * th_seq.
+ */
+ tp->snd_wl1 = th->th_seq;
+ /*
+ * Pull rcv_up up to prevent seq wrap relative to
+ * rcv_nxt.
+ */
+ tp->rcv_up = tp->rcv_nxt;
+ TCP_INC_VAR(tcpstat.tcps_rcvpack, nlropkts);
+ tcpstat.tcps_rcvbyte += tlen;
+ if (nstat_collect) {
+ if (m->m_pkthdr.pkt_flags & PKTF_SW_LRO_PKT) {
+ INP_ADD_STAT(inp, cell, wifi, wired,
+ rxpackets, m->m_pkthdr.lro_npkts);
+ } else {
+ INP_ADD_STAT(inp, cell, wifi, wired,
+ rxpackets, 1);
+ }
+ INP_ADD_STAT(inp, cell, wifi, wired, rxbytes,
+ tlen);
+ inp_set_activity_bitmap(inp);
+ }
+
+ /*
+ * Calculate the RTT on the receiver only if the
+ * connection is in streaming mode and the last
+ * packet was not an end-of-write
+ */
+ if (tp->t_flags & TF_STREAMING_ON) {
+ tcp_compute_rtt(tp, &to, th);
+ }
+
+ tcp_sbrcv_grow(tp, &so->so_rcv, &to, tlen,
+ TCP_AUTORCVBUF_MAX(ifp));
+
+ /*
+ * Add data to socket buffer.
+ */
+ so_recv_data_stat(so, m, 0);
+ m_adj(m, drop_hdrlen); /* delayed header drop */
+
+ /*
+ * If message delivery (SOF_ENABLE_MSGS) is enabled on
+ * this socket, deliver the packet received as an
+ * in-order message with sequence number attached to it.
+ */
+ if (isipv6) {
+ memcpy(&saved_hdr, ip6, sizeof(struct ip6_hdr));
+ ip6 = (struct ip6_hdr *)&saved_hdr[0];
+ } else {
+ memcpy(&saved_hdr, ip, ip->ip_hl << 2);
+ ip = (struct ip *)&saved_hdr[0];
+ }
+ memcpy(&saved_tcphdr, th, sizeof(struct tcphdr));
+ if (sbappendstream_rcvdemux(so, m,
+ th->th_seq - (tp->irs + 1), 0)) {
+ mptcp_handle_input(so);
+ read_wakeup = 1;
+ }
+ th = &saved_tcphdr;
+
+#if INET6
+ if (isipv6) {
+ KERNEL_DEBUG(DBG_LAYER_END, ((th->th_dport << 16) | th->th_sport),
+ (((ip6->ip6_src.s6_addr16[0]) << 16) | (ip6->ip6_dst.s6_addr16[0])),
+ th->th_seq, th->th_ack, th->th_win);
+ } else
+#endif
+ {
+ KERNEL_DEBUG(DBG_LAYER_END, ((th->th_dport << 16) | th->th_sport),
+ (((ip->ip_src.s_addr & 0xffff) << 16) | (ip->ip_dst.s_addr & 0xffff)),
+ th->th_seq, th->th_ack, th->th_win);
+ }
+ TCP_INC_VAR(tp->t_unacksegs, nlropkts);
+ if (DELAY_ACK(tp, th)) {
+ if ((tp->t_flags & TF_DELACK) == 0) {
+ tp->t_flags |= TF_DELACK;
+ tp->t_timer[TCPT_DELACK] = OFFSET_FROM_START(tp, tcp_delack);
+ }
+ } else {
+ tp->t_flags |= TF_ACKNOW;
+ tcp_output(tp);
+ }
+
+ tcp_adaptive_rwtimo_check(tp, tlen);
+
+ if (tlen > 0) {
+ tcp_tfo_rcv_data(tp);
+ }
+
+ tcp_check_timer_state(tp);
+
+ tcp_handle_wakeup(so, read_wakeup, write_wakeup);
+
+ socket_unlock(so, 1);
+ KERNEL_DEBUG(DBG_FNC_TCP_INPUT | DBG_FUNC_END, 0, 0, 0, 0, 0);
+ return;
+ }
+ }
+
+ /*
+ * Calculate amount of space in receive window,
+ * and then do TCP input processing.
+ * Receive window is amount of space in rcv queue,
+ * but not less than advertised window.
+ */
+ socket_lock_assert_owned(so);
+ win = tcp_sbspace(tp);
+ if (win < 0) {
+ win = 0;
+ } else { /* clip rcv window to 4K for modems */
+ if (tp->t_flags & TF_SLOWLINK && slowlink_wsize > 0) {
+ win = min(win, slowlink_wsize);
+ }
+ }
+ tp->rcv_wnd = imax(win, (int)(tp->rcv_adv - tp->rcv_nxt));
+#if MPTCP
+ /*
+ * Ensure that the subflow receive window isn't greater
+ * than the connection level receive window.
+ */
+ if ((tp->t_mpflags & TMPF_MPTCP_TRUE) &&
+ (mp_tp = tptomptp(tp))) {
+ socket_lock_assert_owned(mptetoso(mp_tp->mpt_mpte));
+
+ if (tp->rcv_wnd > (int)(mp_tp->mpt_rcvadv - (uint32_t)mp_tp->mpt_rcvnxt)) {
+ tp->rcv_wnd = mp_tp->mpt_rcvadv - (uint32_t)mp_tp->mpt_rcvnxt;
+ tcpstat.tcps_mp_reducedwin++;
+ }
+ }
+#endif /* MPTCP */
+
+ switch (tp->t_state) {
+ /*
+ * Initialize tp->rcv_nxt, and tp->irs, select an initial
+ * tp->iss, and send a segment:
+ * <SEQ=ISS><ACK=RCV_NXT><CTL=SYN,ACK>
+ * Also initialize tp->snd_nxt to tp->iss+1 and tp->snd_una to tp->iss.
+ * Fill in remote peer address fields if not previously specified.
+ * Enter SYN_RECEIVED state, and process any other fields of this
+ * segment in this state.
+ */
+ case TCPS_LISTEN: {
+ struct sockaddr_in *sin;
+#if INET6
+ struct sockaddr_in6 *sin6;
+#endif
+
+ socket_lock_assert_owned(so);
+
+ /* Clear the logging flags inherited from the listening socket */
+ tp->t_log_flags = 0;
+ tp->t_flagsext &= ~TF_LOGGED_CONN_SUMMARY;
+
+#if INET6
+ if (isipv6) {
+ MALLOC(sin6, struct sockaddr_in6 *, sizeof *sin6,
+ M_SONAME, M_NOWAIT);
+ if (sin6 == NULL) {
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "LISTEN malloc M_SONAME failed");
+ goto drop;
+ }
+ bzero(sin6, sizeof(*sin6));
+ sin6->sin6_family = AF_INET6;
+ sin6->sin6_len = sizeof(*sin6);
+ sin6->sin6_addr = ip6->ip6_src;
+ sin6->sin6_port = th->th_sport;
+ laddr6 = inp->in6p_laddr;
+ if (IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr)) {
+ inp->in6p_laddr = ip6->ip6_dst;
+ }
+ if (in6_pcbconnect(inp, (struct sockaddr *)sin6,
+ proc0)) {
+ inp->in6p_laddr = laddr6;
+ FREE(sin6, M_SONAME);
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, " LISTEN in6_pcbconnect failed");
+ goto drop;
+ }
+ FREE(sin6, M_SONAME);
+ } else
+#endif
+ {
+ socket_lock_assert_owned(so);
+ MALLOC(sin, struct sockaddr_in *, sizeof *sin, M_SONAME,
+ M_NOWAIT);
+ if (sin == NULL) {
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "LISTEN malloc M_SONAME failed");
+ goto drop;
+ }
+ sin->sin_family = AF_INET;
+ sin->sin_len = sizeof(*sin);
+ sin->sin_addr = ip->ip_src;
+ sin->sin_port = th->th_sport;
+ bzero((caddr_t)sin->sin_zero, sizeof(sin->sin_zero));
+ laddr = inp->inp_laddr;
+ if (inp->inp_laddr.s_addr == INADDR_ANY) {
+ inp->inp_laddr = ip->ip_dst;
+ }
+ if (in_pcbconnect(inp, (struct sockaddr *)sin, proc0,
+ IFSCOPE_NONE, NULL)) {
+ inp->inp_laddr = laddr;
+ FREE(sin, M_SONAME);
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, " LISTEN in_pcbconnect failed");
+ goto drop;
+ }
+ FREE(sin, M_SONAME);
+ }
+
+ tcp_dooptions(tp, optp, optlen, th, &to);
+ tcp_finalize_options(tp, &to, ifscope);
+
+ if (tfo_enabled(tp) && tcp_tfo_syn(tp, &to)) {
+ isconnected = TRUE;
+ }
+
+ if (iss) {
+ tp->iss = iss;
+ } else {
+ tp->iss = tcp_new_isn(tp);
+ }
+ tp->irs = th->th_seq;
+ tcp_sendseqinit(tp);
+ tcp_rcvseqinit(tp);
+ tp->snd_recover = tp->snd_una;
+ /*
+ * Initialization of the tcpcb for transaction;
+ * set SND.WND = SEG.WND,
+ * initialize CCsend and CCrecv.
+ */
+ tp->snd_wnd = tiwin; /* initial send-window */
+ tp->max_sndwnd = tp->snd_wnd;
+ tp->t_flags |= TF_ACKNOW;
+ tp->t_unacksegs = 0;
+ DTRACE_TCP4(state__change, void, NULL, struct inpcb *, inp,
+ struct tcpcb *, tp, int32_t, TCPS_SYN_RECEIVED);
+ tp->t_state = TCPS_SYN_RECEIVED;
+ tp->t_timer[TCPT_KEEP] = OFFSET_FROM_START(tp,
+ TCP_CONN_KEEPINIT(tp));
+ tp->t_connect_time = tcp_now;
+ dropsocket = 0; /* committed to socket */
+
+ if (inp->inp_flowhash == 0) {
+ inp->inp_flowhash = inp_calc_flowhash(inp);
+ }
+#if INET6
+ /* update flowinfo - RFC 6437 */
+ if (inp->inp_flow == 0 &&
+ inp->in6p_flags & IN6P_AUTOFLOWLABEL) {
+ inp->inp_flow &= ~IPV6_FLOWLABEL_MASK;
+ inp->inp_flow |=
+ (htonl(inp->inp_flowhash) & IPV6_FLOWLABEL_MASK);
+ }
+#endif /* INET6 */
+
+ /* reset the incomp processing flag */
+ so->so_flags &= ~(SOF_INCOMP_INPROGRESS);
+ tcpstat.tcps_accepts++;
+ if ((thflags & (TH_ECE | TH_CWR)) == (TH_ECE | TH_CWR)) {
+ /* ECN-setup SYN */
+ tp->ecn_flags |= (TE_SETUPRECEIVED | TE_SENDIPECT);
+ }
+
+ /*
+ * The address and connection state are finalized
+ */
+ TCP_LOG_CONNECT(tp, false, 0);
+
+ goto trimthenstep6;
+ }
+
+ /*
+ * If the state is SYN_RECEIVED and the seg contains an ACK,
+ * but not for our SYN/ACK, send a RST.
+ */
+ case TCPS_SYN_RECEIVED:
+ if ((thflags & TH_ACK) &&
+ (SEQ_LEQ(th->th_ack, tp->snd_una) ||
+ SEQ_GT(th->th_ack, tp->snd_max))) {
+ rstreason = BANDLIM_RST_OPENPORT;
+ IF_TCP_STATINC(ifp, ooopacket);
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "SYN_RECEIVED bad ACK");
+ goto dropwithreset;
+ }
+
+ /*
+ * In SYN_RECEIVED state, if we recv some SYNS with
+ * window scale and others without, window scaling should
+ * be disabled. Otherwise the window advertised will be
+ * lower if we assume scaling and the other end does not.
+ */
+ if ((thflags & TH_SYN) &&
+ (tp->irs == th->th_seq) &&
+ !(to.to_flags & TOF_SCALE)) {
+ tp->t_flags &= ~TF_RCVD_SCALE;
+ }
+ break;
+
+ /*
+ * If the state is SYN_SENT:
+ * if seg contains an ACK, but not for our SYN, drop the input.
+ * if seg contains a RST, then drop the connection.
+ * if seg does not contain SYN, then drop it.
+ * Otherwise this is an acceptable SYN segment
+ * initialize tp->rcv_nxt and tp->irs
+ * if seg contains ack then advance tp->snd_una
+ * if SYN has been acked change to ESTABLISHED else SYN_RCVD state
+ * arrange for segment to be acked (eventually)
+ * continue processing rest of data/controls, beginning with URG
+ */
+ case TCPS_SYN_SENT:
+ if ((thflags & TH_ACK) &&
+ (SEQ_LEQ(th->th_ack, tp->iss) ||
+ SEQ_GT(th->th_ack, tp->snd_max))) {
+ rstreason = BANDLIM_UNLIMITED;
+ IF_TCP_STATINC(ifp, ooopacket);
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "SYN_SENT bad ACK");
+ goto dropwithreset;
+ }
+ if (thflags & TH_RST) {
+ if ((thflags & TH_ACK) != 0) {
+ if (tfo_enabled(tp) &&
+ !(tp->t_flagsext & TF_FASTOPEN_FORCE_ENABLE)) {
+ tcp_heuristic_tfo_rst(tp);
+ }
+ if ((tp->ecn_flags & (TE_SETUPSENT | TE_RCVD_SYN_RST)) == TE_SETUPSENT) {
+ /*
+ * On local connections, send
+ * non-ECN syn one time before
+ * dropping the connection
+ */
+ if (tp->t_flags & TF_LOCAL) {
+ tp->ecn_flags |= TE_RCVD_SYN_RST;
+ goto drop;
+ } else {
+ tcp_heuristic_ecn_synrst(tp);
+ }
+ }
+ soevent(so,
+ (SO_FILT_HINT_LOCKED |
+ SO_FILT_HINT_CONNRESET));
+ tp = tcp_drop(tp, ECONNREFUSED);
+ postevent(so, 0, EV_RESET);
+ }
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "SYN_SENT got RST");
+ goto drop;
+ }
+ if ((thflags & TH_SYN) == 0) {
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "SYN_SENT no SYN");
+ goto drop;
+ }
+ tp->snd_wnd = th->th_win; /* initial send window */
+ tp->max_sndwnd = tp->snd_wnd;
+
+ tp->irs = th->th_seq;
+ tcp_rcvseqinit(tp);
+ if (thflags & TH_ACK) {
+ tcpstat.tcps_connects++;
+
+ if ((thflags & (TH_ECE | TH_CWR)) == (TH_ECE)) {
+ /* ECN-setup SYN-ACK */
+ tp->ecn_flags |= TE_SETUPRECEIVED;
+ if (TCP_ECN_ENABLED(tp)) {
+ tcp_heuristic_ecn_success(tp);
+ tcpstat.tcps_ecn_client_success++;
+ }
+ } else {
+ if (tp->ecn_flags & TE_SETUPSENT &&
+ tp->t_rxtshift == 0) {
+ tcp_heuristic_ecn_success(tp);
+ tcpstat.tcps_ecn_not_supported++;
+ }
+ if (tp->ecn_flags & TE_SETUPSENT &&
+ tp->t_rxtshift > 0) {
+ tcp_heuristic_ecn_loss(tp);
+ }
+
+ /* non-ECN-setup SYN-ACK */
+ tp->ecn_flags &= ~TE_SENDIPECT;
+ }
+
+#if CONFIG_MACF_NET && CONFIG_MACF_SOCKET
+ /* XXXMAC: recursive lock: SOCK_LOCK(so); */
+ mac_socketpeer_label_associate_mbuf(m, so);
+ /* XXXMAC: SOCK_UNLOCK(so); */
+#endif
+ /* Do window scaling on this connection? */
+ if (TCP_WINDOW_SCALE_ENABLED(tp)) {
+ tp->snd_scale = tp->requested_s_scale;
+ tp->rcv_scale = tp->request_r_scale;
+ }
+
+ tp->rcv_adv += min(tp->rcv_wnd, TCP_MAXWIN << tp->rcv_scale);
+ tp->snd_una++; /* SYN is acked */
+ if (SEQ_LT(tp->snd_nxt, tp->snd_una)) {
+ tp->snd_nxt = tp->snd_una;
+ }
+
+ /*
+ * We have sent more in the SYN than what is being
+ * acked. (e.g., TFO)
+ * We should restart the sending from what the receiver
+ * has acknowledged immediately.
+ */
+ if (SEQ_GT(tp->snd_nxt, th->th_ack)) {
+ /*
+ * rdar://problem/33214601
+ * There is a middlebox that acks all but one
+ * byte and still drops the data.
+ */
+ if (!(tp->t_flagsext & TF_FASTOPEN_FORCE_ENABLE) &&
+ (tp->t_tfo_stats & TFO_S_SYN_DATA_SENT) &&
+ tp->snd_max == th->th_ack + 1 &&
+ tp->snd_max > tp->snd_una + 1) {
+ tcp_heuristic_tfo_middlebox(tp);
+
+ so->so_error = ENODATA;
+ soevent(so,
+ (SO_FILT_HINT_LOCKED | SO_FILT_HINT_MP_SUB_ERROR));
+
+ tp->t_tfo_stats |= TFO_S_ONE_BYTE_PROXY;
+ }
+
+ tp->snd_max = tp->snd_nxt = th->th_ack;
+ }
+
+ /*
+ * If there's data, delay ACK; if there's also a FIN
+ * ACKNOW will be turned on later.
+ */
+ TCP_INC_VAR(tp->t_unacksegs, nlropkts);
+ if (DELAY_ACK(tp, th) && tlen != 0) {
+ if ((tp->t_flags & TF_DELACK) == 0) {
+ tp->t_flags |= TF_DELACK;
+ tp->t_timer[TCPT_DELACK] = OFFSET_FROM_START(tp, tcp_delack);
+ }
+ } else {
+ tp->t_flags |= TF_ACKNOW;
+ }
+ /*
+ * Received <SYN,ACK> in SYN_SENT[*] state.
+ * Transitions:
+ * SYN_SENT --> ESTABLISHED
+ * SYN_SENT* --> FIN_WAIT_1
+ */
+ tp->t_starttime = tcp_now;
+ tcp_sbrcv_tstmp_check(tp);
+ if (tp->t_flags & TF_NEEDFIN) {
+ DTRACE_TCP4(state__change, void, NULL,
+ struct inpcb *, inp,
+ struct tcpcb *, tp, int32_t,
+ TCPS_FIN_WAIT_1);
+ tp->t_state = TCPS_FIN_WAIT_1;
+ tp->t_flags &= ~TF_NEEDFIN;
+ thflags &= ~TH_SYN;
+
+ TCP_LOG_CONNECTION_SUMMARY(tp);
+ } else {
+ DTRACE_TCP4(state__change, void, NULL,
+ struct inpcb *, inp, struct tcpcb *,
+ tp, int32_t, TCPS_ESTABLISHED);
+ tp->t_state = TCPS_ESTABLISHED;
+ tp->t_timer[TCPT_KEEP] =
+ OFFSET_FROM_START(tp,
+ TCP_CONN_KEEPIDLE(tp));
+ if (nstat_collect) {
+ nstat_route_connect_success(
+ inp->inp_route.ro_rt);
+ }
+ /*
+ * The SYN is acknowledged but una is not
+ * updated yet. So pass the value of
+ * ack to compute sndbytes correctly
+ */
+ inp_count_sndbytes(inp, th->th_ack);
+ }
+#if MPTCP
+ /*
+ * Do not send the connect notification for additional
+ * subflows until ACK for 3-way handshake arrives.
+ */
+ if ((!(tp->t_mpflags & TMPF_MPTCP_TRUE)) &&
+ (tp->t_mpflags & TMPF_SENT_JOIN)) {
+ isconnected = FALSE;
+ } else
+#endif /* MPTCP */
+ isconnected = TRUE;
+
+ if ((tp->t_tfo_flags & (TFO_F_COOKIE_REQ | TFO_F_COOKIE_SENT)) ||
+ (tp->t_tfo_stats & TFO_S_SYN_DATA_SENT)) {
+ tcp_tfo_synack(tp, &to);
+
+ if ((tp->t_tfo_stats & TFO_S_SYN_DATA_SENT) &&
+ SEQ_LT(tp->snd_una, th->th_ack)) {
+ tp->t_tfo_stats |= TFO_S_SYN_DATA_ACKED;
+ tcpstat.tcps_tfo_syn_data_acked++;
+#if MPTCP
+ if (so->so_flags & SOF_MP_SUBFLOW) {
+ so->so_flags1 |= SOF1_TFO_REWIND;
+ }
+#endif
+ tcp_tfo_rcv_probe(tp, tlen);
+ }
+ }
+ } else {
+ /*
+ * Received initial SYN in SYN-SENT[*] state => simul-
+ * taneous open. If segment contains CC option and there is
+ * a cached CC, apply TAO test; if it succeeds, connection is
+ * half-synchronized. Otherwise, do 3-way handshake:
+ * SYN-SENT -> SYN-RECEIVED
+ * SYN-SENT* -> SYN-RECEIVED*
+ */
+ tp->t_flags |= TF_ACKNOW;
+ tp->t_timer[TCPT_REXMT] = 0;
+ DTRACE_TCP4(state__change, void, NULL, struct inpcb *, inp,
+ struct tcpcb *, tp, int32_t, TCPS_SYN_RECEIVED);
+ tp->t_state = TCPS_SYN_RECEIVED;
+
+ /*
+ * During simultaneous open, TFO should not be used.
+ * So, we disable it here, to prevent that data gets
+ * sent on the SYN/ACK.
+ */
+ tcp_disable_tfo(tp);
+ }
+
+trimthenstep6:
+ /*
+ * Advance th->th_seq to correspond to first data byte.
+ * If data, trim to stay within window,
+ * dropping FIN if necessary.
+ */
+ th->th_seq++;
+ if (tlen > tp->rcv_wnd) {
+ todrop = tlen - tp->rcv_wnd;
+ m_adj(m, -todrop);
+ tlen = tp->rcv_wnd;
+ thflags &= ~TH_FIN;
+ tcpstat.tcps_rcvpackafterwin++;
+ tcpstat.tcps_rcvbyteafterwin += todrop;
+ }
+ tp->snd_wl1 = th->th_seq - 1;
+ tp->rcv_up = th->th_seq;
+ /*
+ * Client side of transaction: already sent SYN and data.
+ * If the remote host used T/TCP to validate the SYN,
+ * our data will be ACK'd; if so, enter normal data segment
+ * processing in the middle of step 5, ack processing.
+ * Otherwise, goto step 6.
+ */
+ if (thflags & TH_ACK) {
+ goto process_ACK;
+ }
+ goto step6;
+ /*
+ * If the state is LAST_ACK or CLOSING or TIME_WAIT:
+ * do normal processing.
+ *
+ * NB: Leftover from RFC1644 T/TCP. Cases to be reused later.
+ */
+ case TCPS_LAST_ACK:
+ case TCPS_CLOSING:
+ case TCPS_TIME_WAIT:
+ break; /* continue normal processing */
+
+ /* Received a SYN while connection is already established.
+ * This is a "half open connection and other anomalies" described
+ * in RFC793 page 34, send an ACK so the remote reset the connection
+ * or recovers by adjusting its sequence numbering. Sending an ACK is
+ * in accordance with RFC 5961 Section 4.2
+ */
+ case TCPS_ESTABLISHED:
+ if (thflags & TH_SYN) {
+ /* Drop the packet silently if we have reached the limit */
+ if (tcp_do_rfc5961 && tcp_is_ack_ratelimited(tp)) {
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "ESTABLISHED rfc5961 rate limited");
+ goto drop;
+ } else {
+ /* Send challenge ACK */
+ tcpstat.tcps_synchallenge++;
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "ESTABLISHED rfc5961 challenge ACK");
+ goto dropafterack;
+ }
+ }
+ break;
+ }
+
+ /*
+ * States other than LISTEN or SYN_SENT.
+ * First check the RST flag and sequence number since reset segments
+ * are exempt from the timestamp and connection count tests. This
+ * fixes a bug introduced by the Stevens, vol. 2, p. 960 bugfix
+ * below which allowed reset segments in half the sequence space
+ * to fall though and be processed (which gives forged reset
+ * segments with a random sequence number a 50 percent chance of
+ * killing a connection).
+ * Then check timestamp, if present.
+ * Then check the connection count, if present.
+ * Then check that at least some bytes of segment are within
+ * receive window. If segment begins before rcv_nxt,
+ * drop leading data (and SYN); if nothing left, just ack.
+ *
+ *
+ * If the RST bit is set, check the sequence number to see
+ * if this is a valid reset segment.
+ * RFC 793 page 37:
+ * In all states except SYN-SENT, all reset (RST) segments
+ * are validated by checking their SEQ-fields. A reset is
+ * valid if its sequence number is in the window.
+ * Note: this does not take into account delayed ACKs, so
+ * we should test against last_ack_sent instead of rcv_nxt.
+ * The sequence number in the reset segment is normally an
+ * echo of our outgoing acknowlegement numbers, but some hosts
+ * send a reset with the sequence number at the rightmost edge
+ * of our receive window, and we have to handle this case.
+ * Note 2: Paul Watson's paper "Slipping in the Window" has shown
+ * that brute force RST attacks are possible. To combat this,
+ * we use a much stricter check while in the ESTABLISHED state,
+ * only accepting RSTs where the sequence number is equal to
+ * last_ack_sent. In all other states (the states in which a
+ * RST is more likely), the more permissive check is used.
+ * RFC 5961 Section 3.2: if the RST bit is set, sequence # is
+ * within the receive window and last_ack_sent == seq,
+ * then reset the connection. Otherwise if the seq doesn't
+ * match last_ack_sent, TCP must send challenge ACK. Perform
+ * rate limitation when sending the challenge ACK.
+ * If we have multiple segments in flight, the intial reset
+ * segment sequence numbers will be to the left of last_ack_sent,
+ * but they will eventually catch up.
+ * In any case, it never made sense to trim reset segments to
+ * fit the receive window since RFC 1122 says:
+ * 4.2.2.12 RST Segment: RFC-793 Section 3.4
+ *
+ * A TCP SHOULD allow a received RST segment to include data.
+ *
+ * DISCUSSION
+ * It has been suggested that a RST segment could contain
+ * ASCII text that encoded and explained the cause of the
+ * RST. No standard has yet been established for such
+ * data.
+ *
+ * If the reset segment passes the sequence number test examine
+ * the state:
+ * SYN_RECEIVED STATE:
+ * If passive open, return to LISTEN state.
+ * If active open, inform user that connection was refused.
+ * ESTABLISHED, FIN_WAIT_1, FIN_WAIT_2, CLOSE_WAIT STATES:
+ * Inform user that connection was reset, and close tcb.
+ * CLOSING, LAST_ACK STATES:
+ * Close the tcb.
+ * TIME_WAIT STATE:
+ * Drop the segment - see Stevens, vol. 2, p. 964 and
+ * RFC 1337.
+ *
+ * Radar 4803931: Allows for the case where we ACKed the FIN but
+ * there is already a RST in flight from the peer.
+ * In that case, accept the RST for non-established
+ * state if it's one off from last_ack_sent.
+ *
+ */
+ if (thflags & TH_RST) {
+ if ((SEQ_GEQ(th->th_seq, tp->last_ack_sent) &&
+ SEQ_LT(th->th_seq, tp->last_ack_sent + tp->rcv_wnd)) ||
+ (tp->rcv_wnd == 0 &&
+ ((tp->last_ack_sent == th->th_seq) ||
+ ((tp->last_ack_sent - 1) == th->th_seq)))) {
+ if (tcp_do_rfc5961 == 0 || tp->last_ack_sent == th->th_seq) {
+ switch (tp->t_state) {
+ case TCPS_SYN_RECEIVED:
+ IF_TCP_STATINC(ifp, rstinsynrcv);
+ so->so_error = ECONNREFUSED;
+ goto close;
+
+ case TCPS_ESTABLISHED:
+ if (tcp_do_rfc5961 == 0 && tp->last_ack_sent != th->th_seq) {
+ tcpstat.tcps_badrst++;
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "ESTABLISHED rfc5961 bad RST");
+ goto drop;
+ }
+ if (TCP_ECN_ENABLED(tp) &&
+ tp->snd_una == tp->iss + 1 &&
+ SEQ_GT(tp->snd_max, tp->snd_una)) {
+ /*
+ * If the first data packet on an
+ * ECN connection, receives a RST
+ * increment the heuristic
+ */
+ tcp_heuristic_ecn_droprst(tp);
+ }
+ case TCPS_FIN_WAIT_1:
+ case TCPS_CLOSE_WAIT:
+ /*
+ * Drop through ...
+ */
+ case TCPS_FIN_WAIT_2:
+ so->so_error = ECONNRESET;
+close:
+ postevent(so, 0, EV_RESET);
+ soevent(so,
+ (SO_FILT_HINT_LOCKED |
+ SO_FILT_HINT_CONNRESET));
+
+ tcpstat.tcps_drops++;
+ tp = tcp_close(tp);
+ break;
+
+ case TCPS_CLOSING:
+ case TCPS_LAST_ACK:
+ tp = tcp_close(tp);
+ break;
+
+ case TCPS_TIME_WAIT:
+ break;
+ }
+ } else if (tcp_do_rfc5961) {
+ tcpstat.tcps_badrst++;
+ /* Drop if we have reached the ACK limit */
+ if (tcp_is_ack_ratelimited(tp)) {
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "ESTABLISHED rfc5961 rate limited");
+ goto drop;
+ } else {
+ /* Send challenge ACK */
+ tcpstat.tcps_rstchallenge++;
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "ESTABLISHED rfc5961 challenge ACK");
+ goto dropafterack;
+ }
+ }
+ }
+ goto drop;
+ }
+
+ /*
+ * RFC 1323 PAWS: If we have a timestamp reply on this segment
+ * and it's less than ts_recent, drop it.
+ */
+ if ((to.to_flags & TOF_TS) != 0 && tp->ts_recent &&
+ TSTMP_LT(to.to_tsval, tp->ts_recent)) {
+ /* Check to see if ts_recent is over 24 days old. */
+ if ((int)(tcp_now - tp->ts_recent_age) > TCP_PAWS_IDLE) {
+ /*
+ * Invalidate ts_recent. If this segment updates
+ * ts_recent, the age will be reset later and ts_recent
+ * will get a valid value. If it does not, setting
+ * ts_recent to zero will at least satisfy the
+ * requirement that zero be placed in the timestamp
+ * echo reply when ts_recent isn't valid. The
+ * age isn't reset until we get a valid ts_recent
+ * because we don't want out-of-order segments to be
+ * dropped when ts_recent is old.
+ */
+ tp->ts_recent = 0;
+ } else {
+ tcpstat.tcps_rcvduppack++;
+ tcpstat.tcps_rcvdupbyte += tlen;
+ tp->t_pawsdrop++;
+ tcpstat.tcps_pawsdrop++;
+
+ /*
+ * PAWS-drop when ECN is being used? That indicates
+ * that ECT-marked packets take a different path, with
+ * different congestion-characteristics.
+ *
+ * Only fallback when we did send less than 2GB as PAWS
+ * really has no reason to kick in earlier.
+ */
+ if (TCP_ECN_ENABLED(tp) &&
+ inp->inp_stat->rxbytes < 2147483648) {
+ INP_INC_IFNET_STAT(inp, ecn_fallback_reorder);
+ tcpstat.tcps_ecn_fallback_reorder++;
+ tcp_heuristic_ecn_aggressive(tp);
+ }
+
+ if (nstat_collect) {
+ nstat_route_rx(tp->t_inpcb->inp_route.ro_rt,
+ 1, tlen, NSTAT_RX_FLAG_DUPLICATE);
+ INP_ADD_STAT(inp, cell, wifi, wired,
+ rxpackets, 1);
+ INP_ADD_STAT(inp, cell, wifi, wired,
+ rxbytes, tlen);
+ tp->t_stat.rxduplicatebytes += tlen;
+ inp_set_activity_bitmap(inp);
+ }
+ if (tlen > 0) {
+ goto dropafterack;
+ }
+ goto drop;
+ }
+ }
+
+ /*
+ * In the SYN-RECEIVED state, validate that the packet belongs to
+ * this connection before trimming the data to fit the receive
+ * window. Check the sequence number versus IRS since we know
+ * the sequence numbers haven't wrapped. This is a partial fix
+ * for the "LAND" DoS attack.
+ */
+ if (tp->t_state == TCPS_SYN_RECEIVED && SEQ_LT(th->th_seq, tp->irs)) {
+ rstreason = BANDLIM_RST_OPENPORT;
+ IF_TCP_STATINC(ifp, dospacket);
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "SYN_RECEIVED bad SEQ");
+ goto dropwithreset;
+ }
+
+ /*
+ * Check if there is old data at the beginning of the window
+ * i.e. the sequence number is before rcv_nxt
+ */
+ todrop = tp->rcv_nxt - th->th_seq;
+ if (todrop > 0) {
+ boolean_t is_syn_set = FALSE;
+
+ if (thflags & TH_SYN) {
+ is_syn_set = TRUE;
+ thflags &= ~TH_SYN;
+ th->th_seq++;
+ if (th->th_urp > 1) {
+ th->th_urp--;
+ } else {
+ thflags &= ~TH_URG;
+ }
+ todrop--;
+ }
+ /*
+ * Following if statement from Stevens, vol. 2, p. 960.
+ * The amount of duplicate data is greater than or equal
+ * to the size of the segment - entire segment is duplicate
+ */
+ if (todrop > tlen
+ || (todrop == tlen && (thflags & TH_FIN) == 0)) {
+ /*
+ * Any valid FIN must be to the left of the window.
+ * At this point the FIN must be a duplicate or out
+ * of sequence; drop it.
+ */
+ thflags &= ~TH_FIN;
+
+ /*
+ * Send an ACK to resynchronize and drop any data.
+ * But keep on processing for RST or ACK.
+ *
+ * If the SYN bit was originally set, then only send
+ * an ACK if we are not rate-limiting this connection.
+ */
+ if (tcp_do_rfc5961 && is_syn_set) {
+ if (!tcp_is_ack_ratelimited(tp)) {
+ tcpstat.tcps_synchallenge++;
+ tp->t_flags |= TF_ACKNOW;
+ }
+ } else {
+ tp->t_flags |= TF_ACKNOW;
+ }
+
+ if (todrop == 1) {
+ /* This could be a keepalive */
+ soevent(so, SO_FILT_HINT_LOCKED |
+ SO_FILT_HINT_KEEPALIVE);
+ }
+ todrop = tlen;
+ tcpstat.tcps_rcvduppack++;
+ tcpstat.tcps_rcvdupbyte += todrop;
+ } else {
+ tcpstat.tcps_rcvpartduppack++;
+ tcpstat.tcps_rcvpartdupbyte += todrop;
+ }
+
+ if (TCP_DSACK_ENABLED(tp) && todrop > 1) {
+ /*
+ * Note the duplicate data sequence space so that
+ * it can be reported in DSACK option.
+ */
+ tp->t_dsack_lseq = th->th_seq;
+ tp->t_dsack_rseq = th->th_seq + todrop;
+ tp->t_flags |= TF_ACKNOW;
+ }
+ if (nstat_collect) {
+ nstat_route_rx(tp->t_inpcb->inp_route.ro_rt, 1,
+ todrop, NSTAT_RX_FLAG_DUPLICATE);
+ INP_ADD_STAT(inp, cell, wifi, wired, rxpackets, 1);
+ INP_ADD_STAT(inp, cell, wifi, wired, rxbytes, todrop);
+ tp->t_stat.rxduplicatebytes += todrop;
+ inp_set_activity_bitmap(inp);
+ }
+ drop_hdrlen += todrop; /* drop from the top afterwards */
+ th->th_seq += todrop;
+ tlen -= todrop;
+ if (th->th_urp > todrop) {
+ th->th_urp -= todrop;
+ } else {
+ thflags &= ~TH_URG;
+ th->th_urp = 0;
+ }
+ }
+
+ /*
+ * If new data are received on a connection after the user
+ * processes are gone, then RST the other end.
+ * Send also a RST when we received a data segment after we've
+ * sent our FIN when the socket is defunct.
+ * Note that an MPTCP subflow socket would have SS_NOFDREF set
+ * by default. So, if it's an MPTCP-subflow we rather check the
+ * MPTCP-level's socket state for SS_NOFDREF.
+ */
+ if (tlen) {
+ boolean_t close_it = FALSE;
+
+ if (!(so->so_flags & SOF_MP_SUBFLOW) && (so->so_state & SS_NOFDREF) &&
+ tp->t_state > TCPS_CLOSE_WAIT) {
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "SS_NOFDREF");
+ close_it = TRUE;
+ }
+
+ if ((so->so_flags & SOF_MP_SUBFLOW) && (mptetoso(tptomptp(tp)->mpt_mpte)->so_state & SS_NOFDREF) &&
+ tp->t_state > TCPS_CLOSE_WAIT) {
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "SOF_MP_SUBFLOW SS_NOFDREF");
+ close_it = TRUE;
+ }
+
+ if ((so->so_flags & SOF_DEFUNCT) && tp->t_state > TCPS_FIN_WAIT_1) {
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "SOF_DEFUNCT");
+ close_it = TRUE;
+ }
+
+ if (close_it) {
+ tp = tcp_close(tp);
+ tcpstat.tcps_rcvafterclose++;
+ rstreason = BANDLIM_UNLIMITED;
+ IF_TCP_STATINC(ifp, cleanup);
+ goto dropwithreset;
+ }
+ }
+
+ /*
+ * If segment ends after window, drop trailing data
+ * (and PUSH and FIN); if nothing left, just ACK.
+ */
+ todrop = (th->th_seq + tlen) - (tp->rcv_nxt + tp->rcv_wnd);
+ if (todrop > 0) {
+ tcpstat.tcps_rcvpackafterwin++;
+ if (todrop >= tlen) {
+ tcpstat.tcps_rcvbyteafterwin += tlen;
+ /*
+ * If a new connection request is received
+ * while in TIME_WAIT, drop the old connection
+ * and start over if the sequence numbers
+ * are above the previous ones.
+ */
+ if (thflags & TH_SYN &&
+ tp->t_state == TCPS_TIME_WAIT &&
+ SEQ_GT(th->th_seq, tp->rcv_nxt)) {
+ iss = tcp_new_isn(tp);
+ tp = tcp_close(tp);
+ socket_unlock(so, 1);
+ goto findpcb;
+ }
+ /*
+ * If window is closed can only take segments at
+ * window edge, and have to drop data and PUSH from
+ * incoming segments. Continue processing, but
+ * remember to ack. Otherwise, drop segment
+ * and ack.
+ */
+ if (tp->rcv_wnd == 0 && th->th_seq == tp->rcv_nxt) {
+ tp->t_flags |= TF_ACKNOW;
+ tcpstat.tcps_rcvwinprobe++;
+ } else {
+ goto dropafterack;
+ }
+ } else {
+ tcpstat.tcps_rcvbyteafterwin += todrop;
+ }
+ m_adj(m, -todrop);
+ tlen -= todrop;
+ thflags &= ~(TH_PUSH | TH_FIN);
+ }
+
+ /*
+ * If last ACK falls within this segment's sequence numbers,
+ * record its timestamp.
+ * NOTE:
+ * 1) That the test incorporates suggestions from the latest
+ * proposal of the tcplw@cray.com list (Braden 1993/04/26).
+ * 2) That updating only on newer timestamps interferes with
+ * our earlier PAWS tests, so this check should be solely
+ * predicated on the sequence space of this segment.
+ * 3) That we modify the segment boundary check to be
+ * Last.ACK.Sent <= SEG.SEQ + SEG.Len
+ * instead of RFC1323's
+ * Last.ACK.Sent < SEG.SEQ + SEG.Len,
+ * This modified check allows us to overcome RFC1323's
+ * limitations as described in Stevens TCP/IP Illustrated
+ * Vol. 2 p.869. In such cases, we can still calculate the
+ * RTT correctly when RCV.NXT == Last.ACK.Sent.
+ */
+ if ((to.to_flags & TOF_TS) != 0 &&
+ SEQ_LEQ(th->th_seq, tp->last_ack_sent) &&
+ SEQ_LEQ(tp->last_ack_sent, th->th_seq + tlen +
+ ((thflags & (TH_SYN | TH_FIN)) != 0))) {
+ tp->ts_recent_age = tcp_now;
+ tp->ts_recent = to.to_tsval;
+ }
+
+ /*
+ * Stevens: If a SYN is in the window, then this is an
+ * error and we send an RST and drop the connection.
+ *
+ * RFC 5961 Section 4.2
+ * Send challenge ACK for any SYN in synchronized state
+ * Perform rate limitation in doing so.
+ */
+ if (thflags & TH_SYN) {
+ if (tcp_do_rfc5961) {
+ tcpstat.tcps_badsyn++;
+ /* Drop if we have reached ACK limit */
+ if (tcp_is_ack_ratelimited(tp)) {
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "rfc5961 bad SYN rate limited");
+ goto drop;
+ } else {
+ /* Send challenge ACK */
+ tcpstat.tcps_synchallenge++;
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "rfc5961 bad SYN challenge ack");
+ goto dropafterack;
+ }
+ } else {
+ tp = tcp_drop(tp, ECONNRESET);
+ rstreason = BANDLIM_UNLIMITED;
+ postevent(so, 0, EV_RESET);
+ IF_TCP_STATINC(ifp, synwindow);
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "bad SYN");
+ goto dropwithreset;
+ }
+ }
+
+ /*
+ * If the ACK bit is off: if in SYN-RECEIVED state or SENDSYN
+ * flag is on (half-synchronized state), then queue data for
+ * later processing; else drop segment and return.
+ */
+ if ((thflags & TH_ACK) == 0) {
+ if (tp->t_state == TCPS_SYN_RECEIVED ||
+ (tp->t_flags & TF_NEEDSYN)) {
+ if ((tfo_enabled(tp))) {
+ /*
+ * So, we received a valid segment while in
+ * SYN-RECEIVED (TF_NEEDSYN is actually never
+ * set, so this is dead code).
+ * As this cannot be an RST (see that if a bit
+ * higher), and it does not have the ACK-flag
+ * set, we want to retransmit the SYN/ACK.
+ * Thus, we have to reset snd_nxt to snd_una to
+ * trigger the going back to sending of the
+ * SYN/ACK. This is more consistent with the
+ * behavior of tcp_output(), which expects
+ * to send the segment that is pointed to by
+ * snd_nxt.
+ */
+ tp->snd_nxt = tp->snd_una;
+
+ /*
+ * We need to make absolutely sure that we are
+ * going to reply upon a duplicate SYN-segment.
+ */
+ if (th->th_flags & TH_SYN) {
+ needoutput = 1;
+ }
+ }
+
+ goto step6;
+ } else if (tp->t_flags & TF_ACKNOW) {
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "bad ACK");
+ goto dropafterack;
+ } else {
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "bad ACK");
+ goto drop;
+ }
+ }
+
+ /*
+ * Ack processing.
+ */
+
+ switch (tp->t_state) {
+ /*
+ * In SYN_RECEIVED state, the ack ACKs our SYN, so enter
+ * ESTABLISHED state and continue processing.
+ * The ACK was checked above.
+ */
+ case TCPS_SYN_RECEIVED:
+
+ tcpstat.tcps_connects++;
+
+ /* Do window scaling? */
+ if (TCP_WINDOW_SCALE_ENABLED(tp)) {
+ tp->snd_scale = tp->requested_s_scale;
+ tp->rcv_scale = tp->request_r_scale;
+ tp->snd_wnd = th->th_win << tp->snd_scale;
+ tp->max_sndwnd = tp->snd_wnd;
+ tiwin = tp->snd_wnd;
+ }
+ /*
+ * Make transitions:
+ * SYN-RECEIVED -> ESTABLISHED
+ * SYN-RECEIVED* -> FIN-WAIT-1
+ */
+ tp->t_starttime = tcp_now;
+ tcp_sbrcv_tstmp_check(tp);
+ if (tp->t_flags & TF_NEEDFIN) {
+ DTRACE_TCP4(state__change, void, NULL,
+ struct inpcb *, inp,
+ struct tcpcb *, tp, int32_t, TCPS_FIN_WAIT_1);
+ tp->t_state = TCPS_FIN_WAIT_1;
+ tp->t_flags &= ~TF_NEEDFIN;
+
+ TCP_LOG_CONNECTION_SUMMARY(tp);
+ } else {
+ DTRACE_TCP4(state__change, void, NULL,
+ struct inpcb *, inp,
+ struct tcpcb *, tp, int32_t, TCPS_ESTABLISHED);
+ tp->t_state = TCPS_ESTABLISHED;
+ tp->t_timer[TCPT_KEEP] = OFFSET_FROM_START(tp,
+ TCP_CONN_KEEPIDLE(tp));
+ if (nstat_collect) {
+ nstat_route_connect_success(
+ tp->t_inpcb->inp_route.ro_rt);
+ }
+ /*
+ * The SYN is acknowledged but una is not updated
+ * yet. So pass the value of ack to compute
+ * sndbytes correctly
+ */
+ inp_count_sndbytes(inp, th->th_ack);
+ }
+ /*
+ * If segment contains data or ACK, will call tcp_reass()
+ * later; if not, do so now to pass queued data to user.
+ */
+ if (tlen == 0 && (thflags & TH_FIN) == 0) {
+ if (isipv6) {
+ memcpy(&saved_hdr, ip6, sizeof(struct ip6_hdr));
+ ip6 = (struct ip6_hdr *)&saved_hdr[0];
+ } else {
+ memcpy(&saved_hdr, ip, ip->ip_hl << 2);
+ ip = (struct ip *)&saved_hdr[0];
+ }
+ memcpy(&saved_tcphdr, th, sizeof(struct tcphdr));
+ (void) tcp_reass(tp, (struct tcphdr *)0, &tlen,
+ NULL, ifp, &read_wakeup);
+ th = &saved_tcphdr;
+ }
+ tp->snd_wl1 = th->th_seq - 1;
+
+#if MPTCP
+ /*
+ * Do not send the connect notification for additional subflows
+ * until ACK for 3-way handshake arrives.
+ */
+ if ((!(tp->t_mpflags & TMPF_MPTCP_TRUE)) &&
+ (tp->t_mpflags & TMPF_SENT_JOIN)) {
+ isconnected = FALSE;
+ } else
+#endif /* MPTCP */
+ isconnected = TRUE;
+ if ((tp->t_tfo_flags & TFO_F_COOKIE_VALID)) {
+ /* Done this when receiving the SYN */
+ isconnected = FALSE;
+
+ OSDecrementAtomic(&tcp_tfo_halfcnt);
+
+ /* Panic if something has gone terribly wrong. */
+ VERIFY(tcp_tfo_halfcnt >= 0);
+
+ tp->t_tfo_flags &= ~TFO_F_COOKIE_VALID;
+ }
+
+ /*
+ * In case there is data in the send-queue (e.g., TFO is being
+ * used, or connectx+data has been done), then if we would
+ * "FALLTHROUGH", we would handle this ACK as if data has been
+ * acknowledged. But, we have to prevent this. And this
+ * can be prevented by increasing snd_una by 1, so that the
+ * SYN is not considered as data (snd_una++ is actually also
+ * done in SYN_SENT-state as part of the regular TCP stack).
+ *
+ * In case there is data on this ack as well, the data will be
+ * handled by the label "dodata" right after step6.
+ */
+ if (so->so_snd.sb_cc) {
+ tp->snd_una++; /* SYN is acked */
+ if (SEQ_LT(tp->snd_nxt, tp->snd_una)) {
+ tp->snd_nxt = tp->snd_una;
+ }
+
+ /*
+ * No duplicate-ACK handling is needed. So, we
+ * directly advance to processing the ACK (aka,
+ * updating the RTT estimation,...)
+ *
+ * But, we first need to handle eventual SACKs,
+ * because TFO will start sending data with the
+ * SYN/ACK, so it might be that the client
+ * includes a SACK with its ACK.
+ */
+ if (SACK_ENABLED(tp) &&
+ (to.to_nsacks > 0 ||
+ !TAILQ_EMPTY(&tp->snd_holes))) {
+ tcp_sack_doack(tp, &to, th,
+ &sack_bytes_acked);
+ }
+
+ goto process_ACK;
+ }
+
+ /* FALLTHROUGH */
+
+ /*
+ * In ESTABLISHED state: drop duplicate ACKs; ACK out of range
+ * ACKs. If the ack is in the range
+ * tp->snd_una < th->th_ack <= tp->snd_max
+ * then advance tp->snd_una to th->th_ack and drop
+ * data from the retransmission queue. If this ACK reflects
+ * more up to date window information we update our window information.
+ */
+ case TCPS_ESTABLISHED:
+ case TCPS_FIN_WAIT_1:
+ case TCPS_FIN_WAIT_2:
+ case TCPS_CLOSE_WAIT:
+ case TCPS_CLOSING:
+ case TCPS_LAST_ACK:
+ case TCPS_TIME_WAIT:
+ if (SEQ_GT(th->th_ack, tp->snd_max)) {
+ tcpstat.tcps_rcvacktoomuch++;
+ if (tcp_do_rfc5961 && tcp_is_ack_ratelimited(tp)) {
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "rfc5961 rcvacktoomuch");
+ goto drop;
+ } else {
+ goto dropafterack;
+ }
+ }
+ if (tcp_do_rfc5961 && SEQ_LT(th->th_ack, tp->snd_una - tp->max_sndwnd)) {
+ if (tcp_is_ack_ratelimited(tp)) {
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "rfc5961 bad ACK");
+ goto drop;
+ } else {
+ goto dropafterack;
+ }
+ }
+ if (SACK_ENABLED(tp) && to.to_nsacks > 0) {
+ recvd_dsack = tcp_sack_process_dsack(tp, &to, th);
+ /*
+ * If DSACK is received and this packet has no
+ * other SACK information, it can be dropped.
+ * We do not want to treat it as a duplicate ack.
+ */
+ if (recvd_dsack &&
+ SEQ_LEQ(th->th_ack, tp->snd_una) &&
+ to.to_nsacks == 0) {
+ tcp_bad_rexmt_check(tp, th, &to);
+ goto drop;
+ }
+ }
+
+ if (SACK_ENABLED(tp) &&
+ (to.to_nsacks > 0 || !TAILQ_EMPTY(&tp->snd_holes))) {
+ tcp_sack_doack(tp, &to, th, &sack_bytes_acked);
+ }
+
+#if MPTCP
+ if (tp->t_mpuna && SEQ_GEQ(th->th_ack, tp->t_mpuna)) {
+ if (tp->t_mpflags & TMPF_PREESTABLISHED) {
+ /* MP TCP establishment succeeded */
+ tp->t_mpuna = 0;
+ if (tp->t_mpflags & TMPF_JOINED_FLOW) {
+ if (tp->t_mpflags & TMPF_SENT_JOIN) {
+ tp->t_mpflags &=
+ ~TMPF_PREESTABLISHED;
+ tp->t_mpflags |=
+ TMPF_MPTCP_TRUE;
+
+ tp->t_timer[TCPT_JACK_RXMT] = 0;
+ tp->t_mprxtshift = 0;
+ isconnected = TRUE;
+ } else {
+ isconnected = FALSE;
+ }
+ } else {
+ isconnected = TRUE;
+ }
+ }
+ }
+#endif /* MPTCP */
+
+ tcp_tfo_rcv_ack(tp, th);
+
+ /*
+ * If we have outstanding data (other than
+ * a window probe), this is a completely
+ * duplicate ack and the ack is the biggest we've seen.
+ *
+ * Need to accommodate a change in window on duplicate acks
+ * to allow operating systems that update window during
+ * recovery with SACK
+ */
+ if (SEQ_LEQ(th->th_ack, tp->snd_una)) {
+ if (tlen == 0 && (tiwin == tp->snd_wnd ||
+ (to.to_nsacks > 0 && sack_bytes_acked > 0))) {
+ /*
+ * If both ends send FIN at the same time,
+ * then the ack will be a duplicate ack
+ * but we have to process the FIN. Check
+ * for this condition and process the FIN
+ * instead of the dupack
+ */
+ if ((thflags & TH_FIN) &&
+ !TCPS_HAVERCVDFIN(tp->t_state)) {
+ break;
+ }
+process_dupack:
+#if MPTCP
+ /*
+ * MPTCP options that are ignored must
+ * not be treated as duplicate ACKs.
+ */
+ if (to.to_flags & TOF_MPTCP) {
+ goto drop;
+ }
+
+ if ((isconnected) && (tp->t_mpflags & TMPF_JOINED_FLOW)) {
+ mptcplog((LOG_DEBUG, "MPTCP "
+ "Sockets: bypass ack recovery\n"),
+ MPTCP_SOCKET_DBG,
+ MPTCP_LOGLVL_VERBOSE);
+ break;
+ }
+#endif /* MPTCP */
+ /*
+ * If a duplicate acknowledgement was seen
+ * after ECN, it indicates packet loss in
+ * addition to ECN. Reset INRECOVERY flag
+ * so that we can process partial acks
+ * correctly
+ */
+ if (tp->ecn_flags & TE_INRECOVERY) {
+ tp->ecn_flags &= ~TE_INRECOVERY;
+ }
+
+ tcpstat.tcps_rcvdupack++;
+ ++tp->t_dupacks;
+
+ /*
+ * Check if we need to reset the limit on
+ * early retransmit
+ */
+ if (tp->t_early_rexmt_count > 0 &&
+ TSTMP_GEQ(tcp_now,
+ (tp->t_early_rexmt_win +
+ TCP_EARLY_REXMT_WIN))) {
+ tp->t_early_rexmt_count = 0;
+ }
+
+ /*
+ * Is early retransmit needed? We check for
+ * this when the connection is waiting for
+ * duplicate acks to enter fast recovery.
+ */
+ if (!IN_FASTRECOVERY(tp)) {
+ tcp_early_rexmt_check(tp, th);
+ }
+
+ /*
+ * If we've seen exactly rexmt threshold
+ * of duplicate acks, assume a packet
+ * has been dropped and retransmit it.
+ * Kludge snd_nxt & the congestion
+ * window so we send only this one
+ * packet.
+ *
+ * We know we're losing at the current
+ * window size so do congestion avoidance
+ * (set ssthresh to half the current window
+ * and pull our congestion window back to
+ * the new ssthresh).
+ *
+ * Dup acks mean that packets have left the
+ * network (they're now cached at the receiver)
+ * so bump cwnd by the amount in the receiver
+ * to keep a constant cwnd packets in the
+ * network.
+ */
+ if (tp->t_timer[TCPT_REXMT] == 0 ||
+ (th->th_ack != tp->snd_una
+ && sack_bytes_acked == 0)) {
+ tp->t_dupacks = 0;
+ tp->t_rexmtthresh = tcprexmtthresh;
+ } else if (tp->t_dupacks > tp->t_rexmtthresh ||
+ IN_FASTRECOVERY(tp)) {
+ /*
+ * If this connection was seeing packet
+ * reordering, then recovery might be
+ * delayed to disambiguate between
+ * reordering and loss
+ */
+ if (SACK_ENABLED(tp) && !IN_FASTRECOVERY(tp) &&
+ (tp->t_flagsext &
+ (TF_PKTS_REORDERED | TF_DELAY_RECOVERY)) ==
+ (TF_PKTS_REORDERED | TF_DELAY_RECOVERY)) {
+ /*
+ * Since the SACK information is already
+ * updated, this ACK will be dropped
+ */
+ break;
+ }
+
+ if (SACK_ENABLED(tp)
+ && IN_FASTRECOVERY(tp)) {
+ int awnd;
+
+ /*
+ * Compute the amount of data in flight first.
+ * We can inject new data into the pipe iff
+ * we have less than 1/2 the original window's
+ * worth of data in flight.
+ */
+ awnd = (tp->snd_nxt - tp->snd_fack) +
+ tp->sackhint.sack_bytes_rexmit;
+ if (awnd < tp->snd_ssthresh) {
+ tp->snd_cwnd += tp->t_maxseg;
+ if (tp->snd_cwnd > tp->snd_ssthresh) {
+ tp->snd_cwnd = tp->snd_ssthresh;
+ }
+ }
+ } else {
+ tp->snd_cwnd += tp->t_maxseg;
+ }
+
+ /* Process any window updates */
+ if (tiwin > tp->snd_wnd) {
+ tcp_update_window(tp, thflags,
+ th, tiwin, tlen);
+ }
+ tcp_ccdbg_trace(tp, th,
+ TCP_CC_IN_FASTRECOVERY);
+
+ (void) tcp_output(tp);
+
+ goto drop;
+ } else if (tp->t_dupacks == tp->t_rexmtthresh) {
+ tcp_seq onxt = tp->snd_nxt;
+
+ /*
+ * If we're doing sack, check to
+ * see if we're already in sack
+ * recovery. If we're not doing sack,
+ * check to see if we're in newreno
+ * recovery.
+ */
+ if (SACK_ENABLED(tp)) {
+ if (IN_FASTRECOVERY(tp)) {
+ tp->t_dupacks = 0;
+ break;
+ } else if (tp->t_flagsext & TF_DELAY_RECOVERY) {
+ break;
+ }
+ } else {
+ if (SEQ_LEQ(th->th_ack,
+ tp->snd_recover)) {
+ tp->t_dupacks = 0;
+ break;
+ }
+ }
+ if (tp->t_flags & TF_SENTFIN) {
+ tp->snd_recover = tp->snd_max - 1;
+ } else {
+ tp->snd_recover = tp->snd_max;
+ }
+ tp->t_timer[TCPT_PTO] = 0;
+ tp->t_rtttime = 0;
+
+ /*
+ * If the connection has seen pkt
+ * reordering, delay recovery until
+ * it is clear that the packet
+ * was lost.
+ */
+ if (SACK_ENABLED(tp) &&
+ (tp->t_flagsext &
+ (TF_PKTS_REORDERED | TF_DELAY_RECOVERY))
+ == TF_PKTS_REORDERED &&
+ !IN_FASTRECOVERY(tp) &&
+ tp->t_reorderwin > 0 &&
+ (tp->t_state == TCPS_ESTABLISHED ||
+ tp->t_state == TCPS_FIN_WAIT_1)) {
+ tp->t_timer[TCPT_DELAYFR] =
+ OFFSET_FROM_START(tp,
+ tp->t_reorderwin);
+ tp->t_flagsext |= TF_DELAY_RECOVERY;
+ tcpstat.tcps_delay_recovery++;
+ tcp_ccdbg_trace(tp, th,
+ TCP_CC_DELAY_FASTRECOVERY);
+ break;
+ }
+
+ tcp_rexmt_save_state(tp);
+ /*
+ * If the current tcp cc module has
+ * defined a hook for tasks to run
+ * before entering FR, call it
+ */
+ if (CC_ALGO(tp)->pre_fr != NULL) {
+ CC_ALGO(tp)->pre_fr(tp);
+ }
+ ENTER_FASTRECOVERY(tp);
+ tp->t_timer[TCPT_REXMT] = 0;
+ if (TCP_ECN_ENABLED(tp)) {
+ tp->ecn_flags |= TE_SENDCWR;
+ }
+
+ if (SACK_ENABLED(tp)) {
+ tcpstat.tcps_sack_recovery_episode++;
+ tp->t_sack_recovery_episode++;
+ tp->sack_newdata = tp->snd_nxt;
+ tp->snd_cwnd = tp->t_maxseg;
+ tp->t_flagsext &=
+ ~TF_CWND_NONVALIDATED;
+
+ /* Process any window updates */
+ if (tiwin > tp->snd_wnd) {
+ tcp_update_window(
+ tp, thflags,
+ th, tiwin, tlen);
+ }
+
+ tcp_ccdbg_trace(tp, th,
+ TCP_CC_ENTER_FASTRECOVERY);
+ (void) tcp_output(tp);
+ goto drop;
+ }
+ tp->snd_nxt = th->th_ack;
+ tp->snd_cwnd = tp->t_maxseg;
+
+ /* Process any window updates */
+ if (tiwin > tp->snd_wnd) {
+ tcp_update_window(tp,
+ thflags,
+ th, tiwin, tlen);
+ }
+
+ (void) tcp_output(tp);
+ if (tp->t_flagsext & TF_CWND_NONVALIDATED) {
+ tcp_cc_adjust_nonvalidated_cwnd(tp);
+ } else {
+ tp->snd_cwnd = tp->snd_ssthresh +
+ tp->t_maxseg * tp->t_dupacks;
+ }
+ if (SEQ_GT(onxt, tp->snd_nxt)) {
+ tp->snd_nxt = onxt;
+ }
+
+ tcp_ccdbg_trace(tp, th,
+ TCP_CC_ENTER_FASTRECOVERY);
+ goto drop;
+ } else if (limited_txmt &&
+ ALLOW_LIMITED_TRANSMIT(tp) &&
+ (!(SACK_ENABLED(tp)) || sack_bytes_acked > 0) &&
+ (so->so_snd.sb_cc - (tp->snd_max - tp->snd_una)) > 0) {
+ u_int32_t incr = (tp->t_maxseg * tp->t_dupacks);
+
+ /* Use Limited Transmit algorithm on the first two
+ * duplicate acks when there is new data to transmit
+ */
+ tp->snd_cwnd += incr;
+ tcpstat.tcps_limited_txt++;
+ (void) tcp_output(tp);
+
+ tcp_ccdbg_trace(tp, th, TCP_CC_LIMITED_TRANSMIT);
+
+ /* Reset snd_cwnd back to normal */
+ tp->snd_cwnd -= incr;
+ }
+ }
+ break;
+ }
+ /*
+ * If the congestion window was inflated to account
+ * for the other side's cached packets, retract it.
+ */
+ if (IN_FASTRECOVERY(tp)) {
+ if (SEQ_LT(th->th_ack, tp->snd_recover)) {
+ /*
+ * If we received an ECE and entered
+ * recovery, the subsequent ACKs should
+ * not be treated as partial acks.
+ */
+ if (tp->ecn_flags & TE_INRECOVERY) {
+ goto process_ACK;
+ }
+
+ if (SACK_ENABLED(tp)) {
+ tcp_sack_partialack(tp, th);
+ } else {
+ tcp_newreno_partial_ack(tp, th);
+ }
+ tcp_ccdbg_trace(tp, th, TCP_CC_PARTIAL_ACK);
+ } else {
+ EXIT_FASTRECOVERY(tp);
+ if (CC_ALGO(tp)->post_fr != NULL) {
+ CC_ALGO(tp)->post_fr(tp, th);
+ }
+ tp->t_pipeack = 0;
+ tcp_clear_pipeack_state(tp);
+ tcp_ccdbg_trace(tp, th,
+ TCP_CC_EXIT_FASTRECOVERY);
+ }
+ } else if ((tp->t_flagsext &
+ (TF_PKTS_REORDERED | TF_DELAY_RECOVERY))
+ == (TF_PKTS_REORDERED | TF_DELAY_RECOVERY)) {
+ /*
+ * If the ack acknowledges upto snd_recover or if
+ * it acknowledges all the snd holes, exit
+ * recovery and cancel the timer. Otherwise,
+ * this is a partial ack. Wait for recovery timer
+ * to enter recovery. The snd_holes have already
+ * been updated.
+ */
+ if (SEQ_GEQ(th->th_ack, tp->snd_recover) ||
+ TAILQ_EMPTY(&tp->snd_holes)) {
+ tp->t_timer[TCPT_DELAYFR] = 0;
+ tp->t_flagsext &= ~TF_DELAY_RECOVERY;
+ EXIT_FASTRECOVERY(tp);
+ tcp_ccdbg_trace(tp, th,
+ TCP_CC_EXIT_FASTRECOVERY);
+ }
+ } else {
+ /*
+ * We were not in fast recovery. Reset the
+ * duplicate ack counter.
+ */
+ tp->t_dupacks = 0;
+ tp->t_rexmtthresh = tcprexmtthresh;
+ }
+
+
+ /*
+ * If we reach this point, ACK is not a duplicate,
+ * i.e., it ACKs something we sent.
+ */
+ if (tp->t_flags & TF_NEEDSYN) {
+ /*
+ * T/TCP: Connection was half-synchronized, and our
+ * SYN has been ACK'd (so connection is now fully
+ * synchronized). Go to non-starred state,
+ * increment snd_una for ACK of SYN, and check if
+ * we can do window scaling.
+ */
+ tp->t_flags &= ~TF_NEEDSYN;
+ tp->snd_una++;
+ /* Do window scaling? */
+ if (TCP_WINDOW_SCALE_ENABLED(tp)) {
+ tp->snd_scale = tp->requested_s_scale;
+ tp->rcv_scale = tp->request_r_scale;
+ }
+ }
+
+process_ACK:
+ VERIFY(SEQ_GEQ(th->th_ack, tp->snd_una));
+ acked = BYTES_ACKED(th, tp);
+ tcpstat.tcps_rcvackpack++;
+ tcpstat.tcps_rcvackbyte += acked;
+
+ /*
+ * If the last packet was a retransmit, make sure
+ * it was not spurious.
+ *
+ * This will also take care of congestion window
+ * adjustment if a last packet was recovered due to a
+ * tail loss probe.
+ */
+ tcp_bad_rexmt_check(tp, th, &to);
+
+ /* Recalculate the RTT */
+ tcp_compute_rtt(tp, &to, th);
+
+ /*
+ * If all outstanding data is acked, stop retransmit
+ * timer and remember to restart (more output or persist).
+ * If there is more data to be acked, restart retransmit
+ * timer, using current (possibly backed-off) value.
+ */
+ TCP_RESET_REXMT_STATE(tp);
+ TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp),
+ tp->t_rttmin, TCPTV_REXMTMAX,
+ TCP_ADD_REXMTSLOP(tp));
+ if (th->th_ack == tp->snd_max) {
+ tp->t_timer[TCPT_REXMT] = 0;
+ tp->t_timer[TCPT_PTO] = 0;
+ needoutput = 1;
+ } else if (tp->t_timer[TCPT_PERSIST] == 0) {
+ tp->t_timer[TCPT_REXMT] = OFFSET_FROM_START(tp,
+ tp->t_rxtcur);
+ }
+
+ if ((prev_t_state == TCPS_SYN_SENT ||
+ prev_t_state == TCPS_SYN_RECEIVED) &&
+ tp->t_state == TCPS_ESTABLISHED) {
+ TCP_LOG_RTT_INFO(tp);
+ }
+
+ /*
+ * If no data (only SYN) was ACK'd, skip rest of ACK
+ * processing.
+ */
+ if (acked == 0) {
+ goto step6;
+ }
+
+ /*
+ * When outgoing data has been acked (except the SYN+data), we
+ * mark this connection as "sending good" for TFO.
+ */
+ if ((tp->t_tfo_stats & TFO_S_SYN_DATA_SENT) &&
+ !(tp->t_tfo_flags & TFO_F_NO_SNDPROBING) &&
+ !(th->th_flags & TH_SYN)) {
+ tp->t_tfo_flags |= TFO_F_NO_SNDPROBING;
+ }
+
+ /*
+ * If TH_ECE is received, make sure that ECN is enabled
+ * on that connection and we have sent ECT on data packets.
+ */
+ if ((thflags & TH_ECE) != 0 && TCP_ECN_ENABLED(tp) &&
+ (tp->ecn_flags & TE_SENDIPECT)) {
+ /*
+ * Reduce the congestion window if we haven't
+ * done so.
+ */
+ if (!IN_FASTRECOVERY(tp)) {
+ tcp_reduce_congestion_window(tp);
+ tp->ecn_flags |= (TE_INRECOVERY | TE_SENDCWR);
+ /*
+ * Also note that the connection received
+ * ECE atleast once
+ */
+ tp->ecn_flags |= TE_RECV_ECN_ECE;
+ INP_INC_IFNET_STAT(inp, ecn_recv_ece);
+ tcpstat.tcps_ecn_recv_ece++;
+ tcp_ccdbg_trace(tp, th, TCP_CC_ECN_RCVD);
+ }
+ }
+
+ /*
+ * When new data is acked, open the congestion window.
+ * The specifics of how this is achieved are up to the
+ * congestion control algorithm in use for this connection.
+ *
+ * The calculations in this function assume that snd_una is
+ * not updated yet.
+ */
+ if (!IN_FASTRECOVERY(tp)) {
+ if (CC_ALGO(tp)->ack_rcvd != NULL) {
+ CC_ALGO(tp)->ack_rcvd(tp, th);
+ }
+ tcp_ccdbg_trace(tp, th, TCP_CC_ACK_RCVD);
+ }
+ if (acked > so->so_snd.sb_cc) {
+ tp->snd_wnd -= so->so_snd.sb_cc;
+ sbdrop(&so->so_snd, (int)so->so_snd.sb_cc);
+ if (so->so_flags & SOF_ENABLE_MSGS) {
+ so->so_msg_state->msg_serial_bytes -=
+ (int)so->so_snd.sb_cc;
+ }
+ ourfinisacked = 1;
+ } else {
+ sbdrop(&so->so_snd, acked);
+ if (so->so_flags & SOF_ENABLE_MSGS) {
+ so->so_msg_state->msg_serial_bytes -=
+ acked;
+ }
+ tcp_sbsnd_trim(&so->so_snd);
+ tp->snd_wnd -= acked;
+ ourfinisacked = 0;
+ }
+ /* detect una wraparound */
+ if (!IN_FASTRECOVERY(tp) &&
+ SEQ_GT(tp->snd_una, tp->snd_recover) &&
+ SEQ_LEQ(th->th_ack, tp->snd_recover)) {
+ tp->snd_recover = th->th_ack - 1;
+ }
+
+ if (IN_FASTRECOVERY(tp) &&
+ SEQ_GEQ(th->th_ack, tp->snd_recover)) {
+ EXIT_FASTRECOVERY(tp);
+ }
+
+ tp->snd_una = th->th_ack;
+
+ if (SACK_ENABLED(tp)) {
+ if (SEQ_GT(tp->snd_una, tp->snd_recover)) {
+ tp->snd_recover = tp->snd_una;
+ }
+ }
+ if (SEQ_LT(tp->snd_nxt, tp->snd_una)) {
+ tp->snd_nxt = tp->snd_una;
+ }
+ if (!SLIST_EMPTY(&tp->t_rxt_segments) &&
+ !TCP_DSACK_SEQ_IN_WINDOW(tp, tp->t_dsack_lastuna,
+ tp->snd_una)) {
+ tcp_rxtseg_clean(tp);
+ }
+ if ((tp->t_flagsext & TF_MEASURESNDBW) != 0 &&
+ tp->t_bwmeas != NULL) {
+ tcp_bwmeas_check(tp);
+ }
+
+ write_wakeup = 1;
+
+ if (!SLIST_EMPTY(&tp->t_notify_ack)) {
+ tcp_notify_acknowledgement(tp, so);
+ }
+
+ switch (tp->t_state) {
+ /*
+ * In FIN_WAIT_1 STATE in addition to the processing
+ * for the ESTABLISHED state if our FIN is now acknowledged
+ * then enter FIN_WAIT_2.
+ */
+ case TCPS_FIN_WAIT_1:
+ if (ourfinisacked) {
+ /*
+ * If we can't receive any more
+ * data, then closing user can proceed.
+ * Starting the TCPT_2MSL timer is contrary to the
+ * specification, but if we don't get a FIN
+ * we'll hang forever.
+ */
+ if (so->so_state & SS_CANTRCVMORE) {
+ tp->t_timer[TCPT_2MSL] = OFFSET_FROM_START(tp,
+ TCP_CONN_MAXIDLE(tp));
+ isconnected = FALSE;
+ isdisconnected = TRUE;
+ }
+ DTRACE_TCP4(state__change, void, NULL,
+ struct inpcb *, inp,
+ struct tcpcb *, tp,
+ int32_t, TCPS_FIN_WAIT_2);
+ tp->t_state = TCPS_FIN_WAIT_2;
+ /* fall through and make sure we also recognize
+ * data ACKed with the FIN
+ */
+ }
+ break;
+
+ /*
+ * In CLOSING STATE in addition to the processing for
+ * the ESTABLISHED state if the ACK acknowledges our FIN
+ * then enter the TIME-WAIT state, otherwise ignore
+ * the segment.
+ */
+ case TCPS_CLOSING:
+ if (ourfinisacked) {
+ DTRACE_TCP4(state__change, void, NULL,
+ struct inpcb *, inp,
+ struct tcpcb *, tp,
+ int32_t, TCPS_TIME_WAIT);
+ tp->t_state = TCPS_TIME_WAIT;
+ tcp_canceltimers(tp);
+ if (tp->t_flagsext & TF_NOTIMEWAIT) {
+ tp->t_flags |= TF_CLOSING;
+ } else {
+ add_to_time_wait(tp, 2 * tcp_msl);
+ }
+ isconnected = FALSE;
+ isdisconnected = TRUE;
+ }
+ break;
+
+ /*
+ * In LAST_ACK, we may still be waiting for data to drain
+ * and/or to be acked, as well as for the ack of our FIN.
+ * If our FIN is now acknowledged, delete the TCB,
+ * enter the closed state and return.
+ */
+ case TCPS_LAST_ACK:
+ if (ourfinisacked) {
+ tp = tcp_close(tp);
+ goto drop;
+ }
+ break;
+
+ /*
+ * In TIME_WAIT state the only thing that should arrive
+ * is a retransmission of the remote FIN. Acknowledge
+ * it and restart the finack timer.
+ */
+ case TCPS_TIME_WAIT:
+ add_to_time_wait(tp, 2 * tcp_msl);
+ goto dropafterack;
+ }
+
+ /*
+ * If there is a SACK option on the ACK and we
+ * haven't seen any duplicate acks before, count
+ * it as a duplicate ack even if the cumulative
+ * ack is advanced. If the receiver delayed an
+ * ack and detected loss afterwards, then the ack
+ * will advance cumulative ack and will also have
+ * a SACK option. So counting it as one duplicate
+ * ack is ok.
+ */
+ if (sack_ackadv == 1 &&
+ tp->t_state == TCPS_ESTABLISHED &&
+ SACK_ENABLED(tp) && sack_bytes_acked > 0 &&
+ to.to_nsacks > 0 && tp->t_dupacks == 0 &&
+ SEQ_LEQ(th->th_ack, tp->snd_una) && tlen == 0 &&
+ !(tp->t_flagsext & TF_PKTS_REORDERED)) {
+ tcpstat.tcps_sack_ackadv++;
+ goto process_dupack;
+ }
+ }
+
+step6:
+ /*
+ * Update window information.
+ */
+ if (tcp_update_window(tp, thflags, th, tiwin, tlen)) {
+ needoutput = 1;
+ }
+
+ /*
+ * Process segments with URG.
+ */
+ if ((thflags & TH_URG) && th->th_urp &&
+ TCPS_HAVERCVDFIN(tp->t_state) == 0) {
+ /*
+ * This is a kludge, but if we receive and accept
+ * random urgent pointers, we'll crash in
+ * soreceive. It's hard to imagine someone
+ * actually wanting to send this much urgent data.
+ */
+ if (th->th_urp + so->so_rcv.sb_cc > sb_max) {
+ th->th_urp = 0; /* XXX */
+ thflags &= ~TH_URG; /* XXX */
+ goto dodata; /* XXX */
+ }
+ /*
+ * If this segment advances the known urgent pointer,
+ * then mark the data stream. This should not happen
+ * in CLOSE_WAIT, CLOSING, LAST_ACK or TIME_WAIT STATES since
+ * a FIN has been received from the remote side.
+ * In these states we ignore the URG.
+ *
+ * According to RFC961 (Assigned Protocols),
+ * the urgent pointer points to the last octet
+ * of urgent data. We continue, however,
+ * to consider it to indicate the first octet
+ * of data past the urgent section as the original
+ * spec states (in one of two places).
+ */
+ if (SEQ_GT(th->th_seq + th->th_urp, tp->rcv_up)) {
+ tp->rcv_up = th->th_seq + th->th_urp;
+ so->so_oobmark = so->so_rcv.sb_cc +
+ (tp->rcv_up - tp->rcv_nxt) - 1;
+ if (so->so_oobmark == 0) {
+ so->so_state |= SS_RCVATMARK;
+ postevent(so, 0, EV_OOB);
+ }
+ sohasoutofband(so);
+ tp->t_oobflags &= ~(TCPOOB_HAVEDATA | TCPOOB_HADDATA);
+ }
+ /*
+ * Remove out of band data so doesn't get presented to user.
+ * This can happen independent of advancing the URG pointer,
+ * but if two URG's are pending at once, some out-of-band
+ * data may creep in... ick.
+ */
+ if (th->th_urp <= (u_int32_t)tlen
+#if SO_OOBINLINE
+ && (so->so_options & SO_OOBINLINE) == 0
+#endif
+ ) {
+ tcp_pulloutofband(so, th, m,
+ drop_hdrlen); /* hdr drop is delayed */
+ }
+ } else {
+ /*
+ * If no out of band data is expected,
+ * pull receive urgent pointer along
+ * with the receive window.
+ */
+ if (SEQ_GT(tp->rcv_nxt, tp->rcv_up)) {
+ tp->rcv_up = tp->rcv_nxt;
+ }
+ }
+dodata:
+
+ /* Set socket's connect or disconnect state correcly before doing data.
+ * The following might unlock the socket if there is an upcall or a socket
+ * filter.
+ */
+ if (isconnected) {
+ soisconnected(so);
+ } else if (isdisconnected) {
+ soisdisconnected(so);
+ }
+
+ /* Let's check the state of pcb just to make sure that it did not get closed
+ * when we unlocked above
+ */
+ if (inp->inp_state == INPCB_STATE_DEAD) {
+ /* Just drop the packet that we are processing and return */
+ TCP_LOG_DROP_PCB(TCP_LOG_HDR, th, tp, false, "INPCB_STATE_DEAD");
+ goto drop;
+ }
+
+ /*
+ * Process the segment text, merging it into the TCP sequencing queue,
+ * and arranging for acknowledgment of receipt if necessary.
+ * This process logically involves adjusting tp->rcv_wnd as data
+ * is presented to the user (this happens in tcp_usrreq.c,
+ * case PRU_RCVD). If a FIN has already been received on this
+ * connection then we just ignore the text.
+ *
+ * If we are in SYN-received state and got a valid TFO cookie, we want
+ * to process the data.
+ */
+ if ((tlen || (thflags & TH_FIN)) &&
+ TCPS_HAVERCVDFIN(tp->t_state) == 0 &&
+ (TCPS_HAVEESTABLISHED(tp->t_state) ||
+ (tp->t_state == TCPS_SYN_RECEIVED &&
+ (tp->t_tfo_flags & TFO_F_COOKIE_VALID)))) {
+ tcp_seq save_start = th->th_seq;
+ tcp_seq save_end = th->th_seq + tlen;
+ m_adj(m, drop_hdrlen); /* delayed header drop */
+ /*
+ * Insert segment which includes th into TCP reassembly queue
+ * with control block tp. Set thflags to whether reassembly now
+ * includes a segment with FIN. This handles the common case
+ * inline (segment is the next to be received on an established
+ * connection, and the queue is empty), avoiding linkage into
+ * and removal from the queue and repetition of various
+ * conversions.
+ * Set DELACK for segments received in order, but ack
+ * immediately when segments are out of order (so
+ * fast retransmit can work).
+ */
+ if (th->th_seq == tp->rcv_nxt && LIST_EMPTY(&tp->t_segq)) {
+ TCP_INC_VAR(tp->t_unacksegs, nlropkts);
+ /*
+ * Calculate the RTT on the receiver only if the
+ * connection is in streaming mode and the last
+ * packet was not an end-of-write
+ */
+ if (tp->t_flags & TF_STREAMING_ON) {
+ tcp_compute_rtt(tp, &to, th);
+ }
+
+ if (DELAY_ACK(tp, th) &&
+ ((tp->t_flags & TF_ACKNOW) == 0)) {
+ if ((tp->t_flags & TF_DELACK) == 0) {
+ tp->t_flags |= TF_DELACK;
+ tp->t_timer[TCPT_DELACK] =
+ OFFSET_FROM_START(tp, tcp_delack);
+ }
+ } else {
+ tp->t_flags |= TF_ACKNOW;
+ }
+ tp->rcv_nxt += tlen;
+ thflags = th->th_flags & TH_FIN;
+ TCP_INC_VAR(tcpstat.tcps_rcvpack, nlropkts);
+ tcpstat.tcps_rcvbyte += tlen;
+ if (nstat_collect) {
+ if (m->m_pkthdr.pkt_flags & PKTF_SW_LRO_PKT) {
+ INP_ADD_STAT(inp, cell, wifi, wired,
+ rxpackets, m->m_pkthdr.lro_npkts);
+ } else {
+ INP_ADD_STAT(inp, cell, wifi, wired,
+ rxpackets, 1);
+ }
+ INP_ADD_STAT(inp, cell, wifi, wired,
+ rxbytes, tlen);
+ inp_set_activity_bitmap(inp);
+ }
+ tcp_sbrcv_grow(tp, &so->so_rcv, &to, tlen,
+ TCP_AUTORCVBUF_MAX(ifp));
+ so_recv_data_stat(so, m, drop_hdrlen);
+
+ if (isipv6) {
+ memcpy(&saved_hdr, ip6, sizeof(struct ip6_hdr));
+ ip6 = (struct ip6_hdr *)&saved_hdr[0];
+ } else {
+ memcpy(&saved_hdr, ip, ip->ip_hl << 2);
+ ip = (struct ip *)&saved_hdr[0];
+ }
+ memcpy(&saved_tcphdr, th, sizeof(struct tcphdr));
+ if (sbappendstream_rcvdemux(so, m,
+ th->th_seq - (tp->irs + 1), 0)) {
+ read_wakeup = 1;
+ }
+ th = &saved_tcphdr;
+ } else {
+ if (isipv6) {
+ memcpy(&saved_hdr, ip6, sizeof(struct ip6_hdr));
+ ip6 = (struct ip6_hdr *)&saved_hdr[0];
+ } else {
+ memcpy(&saved_hdr, ip, ip->ip_hl << 2);
+ ip = (struct ip *)&saved_hdr[0];
+ }
+ memcpy(&saved_tcphdr, th, sizeof(struct tcphdr));
+ thflags = tcp_reass(tp, th, &tlen, m, ifp, &read_wakeup);
+ th = &saved_tcphdr;
+ tp->t_flags |= TF_ACKNOW;
+ }
+
+ if ((tlen > 0 || (th->th_flags & TH_FIN)) && SACK_ENABLED(tp)) {
+ if (th->th_flags & TH_FIN) {
+ save_end++;
+ }
+ tcp_update_sack_list(tp, save_start, save_end);
+ }
+
+ tcp_adaptive_rwtimo_check(tp, tlen);
+
+ if (tlen > 0) {
+ tcp_tfo_rcv_data(tp);
+ }
+
+ if (tp->t_flags & TF_DELACK) {
+#if INET6
+ if (isipv6) {
+ KERNEL_DEBUG(DBG_LAYER_END, ((th->th_dport << 16) | th->th_sport),
+ (((ip6->ip6_src.s6_addr16[0]) << 16) | (ip6->ip6_dst.s6_addr16[0])),
+ th->th_seq, th->th_ack, th->th_win);
+ } else
+#endif
+ {
+ KERNEL_DEBUG(DBG_LAYER_END, ((th->th_dport << 16) | th->th_sport),
+ (((ip->ip_src.s_addr & 0xffff) << 16) | (ip->ip_dst.s_addr & 0xffff)),
+ th->th_seq, th->th_ack, th->th_win);
+ }
+ }
+ } else {
+ if ((so->so_flags & SOF_MP_SUBFLOW) && tlen == 0 &&
+ (m->m_pkthdr.pkt_flags & PKTF_MPTCP_DFIN) &&
+ (m->m_pkthdr.pkt_flags & PKTF_MPTCP)) {
+ m_adj(m, drop_hdrlen); /* delayed header drop */
+ mptcp_input(tptomptp(tp)->mpt_mpte, m);
+ tp->t_flags |= TF_ACKNOW;
+ } else {
+ m_freem(m);
+ }
+ thflags &= ~TH_FIN;
+ }
+
+ /*
+ * If FIN is received ACK the FIN and let the user know
+ * that the connection is closing.
+ */
+ if (thflags & TH_FIN) {
+ if (TCPS_HAVERCVDFIN(tp->t_state) == 0) {
+ socantrcvmore(so);
+ postevent(so, 0, EV_FIN);
+ /*
+ * If connection is half-synchronized
+ * (ie NEEDSYN flag on) then delay ACK,
+ * so it may be piggybacked when SYN is sent.
+ * Otherwise, since we received a FIN then no
+ * more input can be expected, send ACK now.
+ */
+ TCP_INC_VAR(tp->t_unacksegs, nlropkts);
+ if (DELAY_ACK(tp, th) && (tp->t_flags & TF_NEEDSYN)) {
+ if ((tp->t_flags & TF_DELACK) == 0) {
+ tp->t_flags |= TF_DELACK;
+ tp->t_timer[TCPT_DELACK] = OFFSET_FROM_START(tp, tcp_delack);
+ }
+ } else {
+ tp->t_flags |= TF_ACKNOW;
+ }
+ tp->rcv_nxt++;
+ }
+ switch (tp->t_state) {
+ /*
+ * In SYN_RECEIVED and ESTABLISHED STATES
+ * enter the CLOSE_WAIT state.
+ */
+ case TCPS_SYN_RECEIVED:
+ tp->t_starttime = tcp_now;
+ case TCPS_ESTABLISHED:
+ DTRACE_TCP4(state__change, void, NULL, struct inpcb *, inp,
+ struct tcpcb *, tp, int32_t, TCPS_CLOSE_WAIT);
+ tp->t_state = TCPS_CLOSE_WAIT;
+ break;
+
+ /*
+ * If still in FIN_WAIT_1 STATE FIN has not been acked so
+ * enter the CLOSING state.
+ */
+ case TCPS_FIN_WAIT_1:
+ DTRACE_TCP4(state__change, void, NULL, struct inpcb *, inp,
+ struct tcpcb *, tp, int32_t, TCPS_CLOSING);
+ tp->t_state = TCPS_CLOSING;
+ break;
+
+ /*
+ * In FIN_WAIT_2 state enter the TIME_WAIT state,
+ * starting the time-wait timer, turning off the other
+ * standard timers.
+ */
+ case TCPS_FIN_WAIT_2:
+ DTRACE_TCP4(state__change, void, NULL,
+ struct inpcb *, inp,
+ struct tcpcb *, tp,
+ int32_t, TCPS_TIME_WAIT);
+ tp->t_state = TCPS_TIME_WAIT;
+ tcp_canceltimers(tp);
+ tp->t_flags |= TF_ACKNOW;
+ if (tp->t_flagsext & TF_NOTIMEWAIT) {
+ tp->t_flags |= TF_CLOSING;
+ } else {
+ add_to_time_wait(tp, 2 * tcp_msl);
+ }
+ soisdisconnected(so);
+ break;
+
+ /*
+ * In TIME_WAIT state restart the 2 MSL time_wait timer.
+ */
+ case TCPS_TIME_WAIT:
+ add_to_time_wait(tp, 2 * tcp_msl);
+ break;
+ }
+ }
+#if TCPDEBUG
+ if (so->so_options & SO_DEBUG) {
+ tcp_trace(TA_INPUT, ostate, tp, (void *)tcp_saveipgen,
+ &tcp_savetcp, 0);
+ }
+#endif
+
+ if (read_wakeup) {
+ mptcp_handle_input(so);
+ }
+
+ /*
+ * Return any desired output.
+ */
+ if (needoutput || (tp->t_flags & TF_ACKNOW)) {
+ (void) tcp_output(tp);
+ }
+
+ tcp_check_timer_state(tp);
+
+ tcp_handle_wakeup(so, read_wakeup, write_wakeup);
+
+ socket_unlock(so, 1);
+ KERNEL_DEBUG(DBG_FNC_TCP_INPUT | DBG_FUNC_END, 0, 0, 0, 0, 0);
+ return;
+
+dropafterack:
+ /*
+ * Generate an ACK dropping incoming segment if it occupies
+ * sequence space, where the ACK reflects our state.
+ *
+ * We can now skip the test for the RST flag since all
+ * paths to this code happen after packets containing
+ * RST have been dropped.
+ *
+ * In the SYN-RECEIVED state, don't send an ACK unless the
+ * segment we received passes the SYN-RECEIVED ACK test.
+ * If it fails send a RST. This breaks the loop in the
+ * "LAND" DoS attack, and also prevents an ACK storm
+ * between two listening ports that have been sent forged
+ * SYN segments, each with the source address of the other.
+ */
+ if (tp->t_state == TCPS_SYN_RECEIVED && (thflags & TH_ACK) &&
+ (SEQ_GT(tp->snd_una, th->th_ack) ||
+ SEQ_GT(th->th_ack, tp->snd_max))) {
+ rstreason = BANDLIM_RST_OPENPORT;
+ IF_TCP_STATINC(ifp, dospacket);
+ goto dropwithreset;
+ }
+#if TCPDEBUG
+ if (so->so_options & SO_DEBUG) {
+ tcp_trace(TA_DROP, ostate, tp, (void *)tcp_saveipgen,
+ &tcp_savetcp, 0);
+ }
+#endif
+ m_freem(m);
+ tp->t_flags |= TF_ACKNOW;
+
+ (void) tcp_output(tp);
+
+ tcp_handle_wakeup(so, read_wakeup, write_wakeup);
+
+ /* Don't need to check timer state as we should have done it during tcp_output */
+ socket_unlock(so, 1);
+ KERNEL_DEBUG(DBG_FNC_TCP_INPUT | DBG_FUNC_END, 0, 0, 0, 0, 0);
+ return;
+dropwithresetnosock:
+ nosock = 1;
+dropwithreset:
+ /*
+ * Generate a RST, dropping incoming segment.
+ * Make ACK acceptable to originator of segment.
+ * Don't bother to respond if destination was broadcast/multicast.
+ */
+ if ((thflags & TH_RST) || m->m_flags & (M_BCAST | M_MCAST)) {
+ goto drop;
+ }
+#if INET6
+ if (isipv6) {
+ if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
+ IN6_IS_ADDR_MULTICAST(&ip6->ip6_src)) {
+ goto drop;
+ }
+ } else
+#endif /* INET6 */
+ if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)) ||
+ IN_MULTICAST(ntohl(ip->ip_src.s_addr)) ||
+ ip->ip_src.s_addr == htonl(INADDR_BROADCAST) ||
+ in_broadcast(ip->ip_dst, m->m_pkthdr.rcvif)) {
+ goto drop;
+ }
+ /* IPv6 anycast check is done at tcp6_input() */
+
+ /*
+ * Perform bandwidth limiting.
+ */
+#if ICMP_BANDLIM
+ if (badport_bandlim(rstreason) < 0) {
+ goto drop;
+ }
+#endif
+
+#if TCPDEBUG
+ if (tp == 0 || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) {
+ tcp_trace(TA_DROP, ostate, tp, (void *)tcp_saveipgen,
+ &tcp_savetcp, 0);
+ }
+#endif
+ bzero(&tra, sizeof(tra));
+ tra.ifscope = ifscope;
+ tra.awdl_unrestricted = 1;
+ tra.intcoproc_allowed = 1;
+ if (thflags & TH_ACK) {
+ /* mtod() below is safe as long as hdr dropping is delayed */
+ tcp_respond(tp, mtod(m, void *), th, m, (tcp_seq)0, th->th_ack,
+ TH_RST, &tra);
+ } else {
+ if (thflags & TH_SYN) {
+ tlen++;
+ }
+ /* mtod() below is safe as long as hdr dropping is delayed */
+ tcp_respond(tp, mtod(m, void *), th, m, th->th_seq + tlen,
+ (tcp_seq)0, TH_RST | TH_ACK, &tra);
+ }
+ /* destroy temporarily created socket */
+ if (dropsocket) {
+ (void) soabort(so);
+ socket_unlock(so, 1);
+ } else if ((inp != NULL) && (nosock == 0)) {
+ tcp_handle_wakeup(so, read_wakeup, write_wakeup);
+
+ socket_unlock(so, 1);
+ }
+ KERNEL_DEBUG(DBG_FNC_TCP_INPUT | DBG_FUNC_END, 0, 0, 0, 0, 0);
+ return;
+dropnosock:
+ nosock = 1;
+drop:
+ /*
+ * Drop space held by incoming segment and return.
+ */
+#if TCPDEBUG
+ if (tp == 0 || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) {
+ tcp_trace(TA_DROP, ostate, tp, (void *)tcp_saveipgen,
+ &tcp_savetcp, 0);
+ }
+#endif
+ m_freem(m);
+ /* destroy temporarily created socket */
+ if (dropsocket) {
+ (void) soabort(so);
+ socket_unlock(so, 1);
+ } else if (nosock == 0) {
+ tcp_handle_wakeup(so, read_wakeup, write_wakeup);
+
+ socket_unlock(so, 1);
+ }
+ KERNEL_DEBUG(DBG_FNC_TCP_INPUT | DBG_FUNC_END, 0, 0, 0, 0, 0);
+ return;
+}
+
+/*
+ * Parse TCP options and place in tcpopt.
+ */
+static void
+tcp_dooptions(struct tcpcb *tp, u_char *cp, int cnt, struct tcphdr *th,
+ struct tcpopt *to)
+{
+ u_short mss = 0;
+ int opt, optlen;
+
+ for (; cnt > 0; cnt -= optlen, cp += optlen) {
+ opt = cp[0];
+ if (opt == TCPOPT_EOL) {
+ break;
+ }
+ if (opt == TCPOPT_NOP) {
+ optlen = 1;
+ } else {
+ if (cnt < 2) {
+ break;
+ }
+ optlen = cp[1];
+ if (optlen < 2 || optlen > cnt) {
+ break;
+ }
+ }
+ switch (opt) {
+ default:
+ continue;
+
+ case TCPOPT_MAXSEG:
+ if (optlen != TCPOLEN_MAXSEG) {
+ continue;
+ }
+ if (!(th->th_flags & TH_SYN)) {
+ continue;
+ }
+ bcopy((char *) cp + 2, (char *) &mss, sizeof(mss));
+ NTOHS(mss);
+ to->to_mss = mss;
+ to->to_flags |= TOF_MSS;
+ break;
+
+ case TCPOPT_WINDOW:
+ if (optlen != TCPOLEN_WINDOW) {
+ continue;
+ }
+ if (!(th->th_flags & TH_SYN)) {
+ continue;
+ }
+ to->to_flags |= TOF_SCALE;
+ to->to_requested_s_scale = min(cp[2], TCP_MAX_WINSHIFT);
+ break;
+
+ case TCPOPT_TIMESTAMP:
+ if (optlen != TCPOLEN_TIMESTAMP) {
+ continue;
+ }
+ to->to_flags |= TOF_TS;
+ bcopy((char *)cp + 2,
+ (char *)&to->to_tsval, sizeof(to->to_tsval));
+ NTOHL(to->to_tsval);
+ bcopy((char *)cp + 6,
+ (char *)&to->to_tsecr, sizeof(to->to_tsecr));
+ NTOHL(to->to_tsecr);
+ /* Re-enable sending Timestamps if we received them */
+ if (!(tp->t_flags & TF_REQ_TSTMP) &&
+ tcp_do_rfc1323 == 1) {
+ tp->t_flags |= TF_REQ_TSTMP;
+ }
+ break;
+ case TCPOPT_SACK_PERMITTED:
+ if (!tcp_do_sack ||
+ optlen != TCPOLEN_SACK_PERMITTED) {
+ continue;
+ }
+ if (th->th_flags & TH_SYN) {
+ to->to_flags |= TOF_SACK;
+ }
+ break;
+ case TCPOPT_SACK:
+ if (optlen <= 2 || (optlen - 2) % TCPOLEN_SACK != 0) {
+ continue;
+ }
+ to->to_nsacks = (optlen - 2) / TCPOLEN_SACK;
+ to->to_sacks = cp + 2;
+ tcpstat.tcps_sack_rcv_blocks++;
+
+ break;
+ case TCPOPT_FASTOPEN:
+ if (optlen == TCPOLEN_FASTOPEN_REQ) {
+ if (tp->t_state != TCPS_LISTEN) {
+ continue;
+ }
+
+ to->to_flags |= TOF_TFOREQ;
+ } else {
+ if (optlen < TCPOLEN_FASTOPEN_REQ ||
+ (optlen - TCPOLEN_FASTOPEN_REQ) > TFO_COOKIE_LEN_MAX ||
+ (optlen - TCPOLEN_FASTOPEN_REQ) < TFO_COOKIE_LEN_MIN) {
+ continue;
+ }
+ if (tp->t_state != TCPS_LISTEN &&
+ tp->t_state != TCPS_SYN_SENT) {
+ continue;
+ }
+
+ to->to_flags |= TOF_TFO;
+ to->to_tfo = cp + 1;
+ }
+
+ break;
+#if MPTCP
+ case TCPOPT_MULTIPATH:
+ tcp_do_mptcp_options(tp, cp, th, to, optlen);
+ break;
+#endif /* MPTCP */
+ }
+ }
+}
+
+static void
+tcp_finalize_options(struct tcpcb *tp, struct tcpopt *to, unsigned int ifscope)
+{
+ if (to->to_flags & TOF_TS) {
+ tp->t_flags |= TF_RCVD_TSTMP;
+ tp->ts_recent = to->to_tsval;
+ tp->ts_recent_age = tcp_now;
+ }
+ if (to->to_flags & TOF_MSS) {
+ tcp_mss(tp, to->to_mss, ifscope);
+ }
+ if (SACK_ENABLED(tp)) {
+ if (!(to->to_flags & TOF_SACK)) {
+ tp->t_flagsext &= ~(TF_SACK_ENABLE);
+ } else {
+ tp->t_flags |= TF_SACK_PERMIT;
+ }
+ }
+ if (to->to_flags & TOF_SCALE) {
+ tp->t_flags |= TF_RCVD_SCALE;
+ tp->requested_s_scale = to->to_requested_s_scale;
+
+ /* Re-enable window scaling, if the option is received */
+ if (tp->request_r_scale > 0) {
+ tp->t_flags |= TF_REQ_SCALE;
+ }
+ }
+}
+
+/*
+ * Pull out of band byte out of a segment so
+ * it doesn't appear in the user's data queue.
+ * It is still reflected in the segment length for
+ * sequencing purposes.
+ *
+ * @param off delayed to be droped hdrlen
+ */
+static void
+tcp_pulloutofband(struct socket *so, struct tcphdr *th, struct mbuf *m, int off)
+{
+ int cnt = off + th->th_urp - 1;
+
+ while (cnt >= 0) {
+ if (m->m_len > cnt) {
+ char *cp = mtod(m, caddr_t) + cnt;
+ struct tcpcb *tp = sototcpcb(so);
+
+ tp->t_iobc = *cp;
+ tp->t_oobflags |= TCPOOB_HAVEDATA;
+ bcopy(cp + 1, cp, (unsigned)(m->m_len - cnt - 1));
+ m->m_len--;
+ if (m->m_flags & M_PKTHDR) {
+ m->m_pkthdr.len--;
+ }
+ return;
+ }
+ cnt -= m->m_len;
+ m = m->m_next;
+ if (m == 0) {
+ break;
+ }
+ }
+ panic("tcp_pulloutofband");
+}
+
+uint32_t
+get_base_rtt(struct tcpcb *tp)
+{
+ struct rtentry *rt = tp->t_inpcb->inp_route.ro_rt;
+ return (rt == NULL) ? 0 : rt->rtt_min;
+}
+
+/* Each value of RTT base represents the minimum RTT seen in a minute.
+ * We keep upto N_RTT_BASE minutes worth of history.
+ */
+void
+update_base_rtt(struct tcpcb *tp, uint32_t rtt)
+{
+ u_int32_t base_rtt, i;
+ struct rtentry *rt;
+
+ if ((rt = tp->t_inpcb->inp_route.ro_rt) == NULL) {
+ return;
+ }
+ if (rt->rtt_expire_ts == 0) {
+ RT_LOCK_SPIN(rt);
+ if (rt->rtt_expire_ts != 0) {
+ RT_UNLOCK(rt);
+ goto update;
+ }
+ rt->rtt_expire_ts = tcp_now;
+ rt->rtt_index = 0;
+ rt->rtt_hist[0] = rtt;
+ rt->rtt_min = rtt;
+ RT_UNLOCK(rt);
+ return;
+ }
+update:
+#if TRAFFIC_MGT
+ /*
+ * If the recv side is being throttled, check if the
+ * current RTT is closer to the base RTT seen in
+ * first (recent) two slots. If so, unthrottle the stream.
+ */
+ if ((tp->t_flagsext & TF_RECV_THROTTLE) &&
+ (int)(tcp_now - tp->t_recv_throttle_ts) >= TCP_RECV_THROTTLE_WIN) {
+ base_rtt = rt->rtt_min;
+ if (tp->t_rttcur <= (base_rtt + target_qdelay)) {
+ tp->t_flagsext &= ~TF_RECV_THROTTLE;
+ tp->t_recv_throttle_ts = 0;
+ }
+ }
+#endif /* TRAFFIC_MGT */
+ if ((int)(tcp_now - rt->rtt_expire_ts) >=
+ TCP_RTT_HISTORY_EXPIRE_TIME) {
+ RT_LOCK_SPIN(rt);
+ /* check the condition again to avoid race */
+ if ((int)(tcp_now - rt->rtt_expire_ts) >=
+ TCP_RTT_HISTORY_EXPIRE_TIME) {
+ rt->rtt_index++;
+ if (rt->rtt_index >= NRTT_HIST) {
+ rt->rtt_index = 0;
+ }
+ rt->rtt_hist[rt->rtt_index] = rtt;
+ rt->rtt_expire_ts = tcp_now;
+ } else {
+ rt->rtt_hist[rt->rtt_index] =
+ min(rt->rtt_hist[rt->rtt_index], rtt);
+ }
+ /* forget the old value and update minimum */
+ rt->rtt_min = 0;
+ for (i = 0; i < NRTT_HIST; ++i) {
+ if (rt->rtt_hist[i] != 0 &&
+ (rt->rtt_min == 0 ||
+ rt->rtt_hist[i] < rt->rtt_min)) {
+ rt->rtt_min = rt->rtt_hist[i];
+ }
+ }
+ RT_UNLOCK(rt);
+ } else {
+ rt->rtt_hist[rt->rtt_index] =
+ min(rt->rtt_hist[rt->rtt_index], rtt);
+ if (rt->rtt_min == 0) {
+ rt->rtt_min = rtt;
+ } else {
+ rt->rtt_min = min(rt->rtt_min, rtt);
+ }
+ }
+}
+
+/*
+ * If we have a timestamp reply, update smoothed RTT. If no timestamp is
+ * present but transmit timer is running and timed sequence number was
+ * acked, update smoothed RTT.
+ *
+ * If timestamps are supported, a receiver can update RTT even if
+ * there is no outstanding data.
+ *
+ * Some boxes send broken timestamp replies during the SYN+ACK phase,
+ * ignore timestamps of 0or we could calculate a huge RTT and blow up
+ * the retransmit timer.
+ */
+static void
+tcp_compute_rtt(struct tcpcb *tp, struct tcpopt *to, struct tcphdr *th)
+{
+ int rtt = 0;
+ VERIFY(to != NULL && th != NULL);
+ if (tp->t_rtttime != 0 && SEQ_GT(th->th_ack, tp->t_rtseq)) {
+ u_int32_t pipe_ack_val;
+ rtt = tcp_now - tp->t_rtttime;
+ /*
+ * Compute pipe ack -- the amount of data acknowledged
+ * in the last RTT
+ */
+ if (SEQ_GT(th->th_ack, tp->t_pipeack_lastuna)) {
+ pipe_ack_val = th->th_ack - tp->t_pipeack_lastuna;
+ /* Update the sample */
+ tp->t_pipeack_sample[tp->t_pipeack_ind++] =
+ pipe_ack_val;
+ tp->t_pipeack_ind %= TCP_PIPEACK_SAMPLE_COUNT;
+
+ /* Compute the max of the pipeack samples */
+ pipe_ack_val = tcp_get_max_pipeack(tp);
+ tp->t_pipeack = (pipe_ack_val >
+ TCP_CC_CWND_INIT_BYTES) ?
+ pipe_ack_val : 0;
+ }
+ /* start another measurement */
+ tp->t_rtttime = 0;
+ }
+ if (((to->to_flags & TOF_TS) != 0) &&
+ (to->to_tsecr != 0) &&
+ TSTMP_GEQ(tcp_now, to->to_tsecr)) {
+ tcp_xmit_timer(tp, (tcp_now - to->to_tsecr),
+ to->to_tsecr, th->th_ack);
+ } else if (rtt > 0) {
+ tcp_xmit_timer(tp, rtt, 0, th->th_ack);
+ }
+}
+
+/*
+ * Collect new round-trip time estimate and update averages and
+ * current timeout.
+ */
+static void
+tcp_xmit_timer(struct tcpcb *tp, int rtt,
+ u_int32_t tsecr, tcp_seq th_ack)
+{
+ int delta;
+ int old_srtt = tp->t_srtt;
+ int old_rttvar = tp->t_rttvar;
+ bool log_rtt = false;
+
+ /*
+ * On AWDL interface, the initial RTT measurement on SYN
+ * can be wrong due to peer caching. Avoid the first RTT
+ * measurement as it might skew up the RTO.
+ * <rdar://problem/28739046>
+ */
+ if (tp->t_inpcb->inp_last_outifp != NULL &&
+ (tp->t_inpcb->inp_last_outifp->if_eflags & IFEF_AWDL) &&
+ th_ack == tp->iss + 1) {
+ return;
+ }
+
+ if (tp->t_flagsext & TF_RECOMPUTE_RTT) {
+ if (SEQ_GT(th_ack, tp->snd_una) &&
+ SEQ_LEQ(th_ack, tp->snd_max) &&
+ (tsecr == 0 ||
+ TSTMP_GEQ(tsecr, tp->t_badrexmt_time))) {
+ /*
+ * We received a new ACk after a
+ * spurious timeout. Adapt retransmission
+ * timer as described in rfc 4015.
+ */
+ tp->t_flagsext &= ~(TF_RECOMPUTE_RTT);
+ tp->t_badrexmt_time = 0;
+ tp->t_srtt = max(tp->t_srtt_prev, rtt);
+ tp->t_srtt = tp->t_srtt << TCP_RTT_SHIFT;
+ tp->t_rttvar = max(tp->t_rttvar_prev, (rtt >> 1));
+ tp->t_rttvar = tp->t_rttvar << TCP_RTTVAR_SHIFT;
+
+ if (tp->t_rttbest > (tp->t_srtt + tp->t_rttvar)) {
+ tp->t_rttbest = tp->t_srtt + tp->t_rttvar;
+ }
+
+ goto compute_rto;
+ } else {
+ return;
+ }
+ }
+
+ tcpstat.tcps_rttupdated++;
+ tp->t_rttupdated++;
+
+ if (rtt > 0) {
+ tp->t_rttcur = rtt;
+ update_base_rtt(tp, rtt);
+ }
+
+ if (tp->t_srtt != 0) {
+ /*
+ * srtt is stored as fixed point with 5 bits after the
+ * binary point (i.e., scaled by 32). The following magic
+ * is equivalent to the smoothing algorithm in rfc793 with
+ * an alpha of .875 (srtt = rtt/8 + srtt*7/8 in fixed
+ * point).
+ *
+ * Freebsd adjusts rtt to origin 0 by subtracting 1
+ * from the provided rtt value. This was required because
+ * of the way t_rtttime was initiailised to 1 before.
+ * Since we changed t_rtttime to be based on
+ * tcp_now, this extra adjustment is not needed.
+ */
+ delta = (rtt << TCP_DELTA_SHIFT)
+ - (tp->t_srtt >> (TCP_RTT_SHIFT - TCP_DELTA_SHIFT));
+
+ if ((tp->t_srtt += delta) <= 0) {
+ tp->t_srtt = 1;
+ }
+
+ /*
+ * We accumulate a smoothed rtt variance (actually, a
+ * smoothed mean difference), then set the retransmit
+ * timer to smoothed rtt + 4 times the smoothed variance.
+ * rttvar is stored as fixed point with 4 bits after the
+ * binary point (scaled by 16). The following is
+ * equivalent to rfc793 smoothing with an alpha of .75
+ * (rttvar = rttvar*3/4 + |delta| / 4). This replaces
+ * rfc793's wired-in beta.
+ */
+ if (delta < 0) {
+ delta = -delta;
+ }
+ delta -= tp->t_rttvar >> (TCP_RTTVAR_SHIFT - TCP_DELTA_SHIFT);
+ if ((tp->t_rttvar += delta) <= 0) {
+ tp->t_rttvar = 1;
+ }
+ if (tp->t_rttbest == 0 ||
+ tp->t_rttbest > (tp->t_srtt + tp->t_rttvar)) {
+ tp->t_rttbest = tp->t_srtt + tp->t_rttvar;
+ }
+ } else {
+ /*
+ * No rtt measurement yet - use the unsmoothed rtt.
+ * Set the variance to half the rtt (so our first
+ * retransmit happens at 3*rtt).
+ */
+ tp->t_srtt = rtt << TCP_RTT_SHIFT;
+ tp->t_rttvar = rtt << (TCP_RTTVAR_SHIFT - 1);
+ }
+
+compute_rto:
+ nstat_route_rtt(tp->t_inpcb->inp_route.ro_rt, tp->t_srtt,
+ tp->t_rttvar);
+
+ /*
+ * the retransmit should happen at rtt + 4 * rttvar.
+ * Because of the way we do the smoothing, srtt and rttvar
+ * will each average +1/2 tick of bias. When we compute
+ * the retransmit timer, we want 1/2 tick of rounding and
+ * 1 extra tick because of +-1/2 tick uncertainty in the
+ * firing of the timer. The bias will give us exactly the
+ * 1.5 tick we need. But, because the bias is
+ * statistical, we have to test that we don't drop below
+ * the minimum feasible timer (which is 2 ticks).
+ */
+ TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp),
+ max(tp->t_rttmin, rtt + 2), TCPTV_REXMTMAX,
+ TCP_ADD_REXMTSLOP(tp));
+
+ /*
+ * We received an ack for a packet that wasn't retransmitted;
+ * it is probably safe to discard any error indications we've
+ * received recently. This isn't quite right, but close enough
+ * for now (a route might have failed after we sent a segment,
+ * and the return path might not be symmetrical).
+ */
+ tp->t_softerror = 0;
+
+ if (log_rtt) {
+ TCP_LOG_RTT_INFO(tp);
+ }
+
+ TCP_LOG_RTT_CHANGE(tp, old_srtt, old_rttvar);
+}
+
+static inline unsigned int
+tcp_maxmtu(struct rtentry *rt)
+{
+ unsigned int maxmtu;
+ int interface_mtu = 0;
+
+ RT_LOCK_ASSERT_HELD(rt);
+ interface_mtu = rt->rt_ifp->if_mtu;
+
+ if (rt_key(rt)->sa_family == AF_INET &&
+ INTF_ADJUST_MTU_FOR_CLAT46(rt->rt_ifp)) {
+ interface_mtu = IN6_LINKMTU(rt->rt_ifp);
+ /* Further adjust the size for CLAT46 expansion */
+ interface_mtu -= CLAT46_HDR_EXPANSION_OVERHD;
+ }
+
+ if (rt->rt_rmx.rmx_mtu == 0) {
+ maxmtu = interface_mtu;
+ } else {
+ maxmtu = MIN(rt->rt_rmx.rmx_mtu, interface_mtu);
+ }
+
+ return maxmtu;
+}
+
+#if INET6
+static inline unsigned int
+tcp_maxmtu6(struct rtentry *rt)
+{
+ unsigned int maxmtu;
+ struct nd_ifinfo *ndi = NULL;
+
+ RT_LOCK_ASSERT_HELD(rt);
+ if ((ndi = ND_IFINFO(rt->rt_ifp)) != NULL && !ndi->initialized) {
+ ndi = NULL;
+ }
+ if (ndi != NULL) {
+ lck_mtx_lock(&ndi->lock);
+ }
+ if (rt->rt_rmx.rmx_mtu == 0) {
+ maxmtu = IN6_LINKMTU(rt->rt_ifp);
+ } else {
+ maxmtu = MIN(rt->rt_rmx.rmx_mtu, IN6_LINKMTU(rt->rt_ifp));
+ }
+ if (ndi != NULL) {
+ lck_mtx_unlock(&ndi->lock);
+ }
+
+ return maxmtu;
+}
+#endif
+
+unsigned int
+get_maxmtu(struct rtentry *rt)
+{
+ unsigned int maxmtu = 0;
+
+ RT_LOCK_ASSERT_NOTHELD(rt);
+
+ RT_LOCK(rt);
+
+ if (rt_key(rt)->sa_family == AF_INET6) {
+ maxmtu = tcp_maxmtu6(rt);
+ } else {
+ maxmtu = tcp_maxmtu(rt);
+ }
+
+ RT_UNLOCK(rt);
+
+ return maxmtu;
+}
+
+/*
+ * Determine a reasonable value for maxseg size.
+ * If the route is known, check route for mtu.
+ * If none, use an mss that can be handled on the outgoing
+ * interface without forcing IP to fragment; if bigger than
+ * an mbuf cluster (MCLBYTES), round down to nearest multiple of MCLBYTES
+ * to utilize large mbufs. If no route is found, route has no mtu,
+ * or the destination isn't local, use a default, hopefully conservative
+ * size (usually 512 or the default IP max size, but no more than the mtu
+ * of the interface), as we can't discover anything about intervening
+ * gateways or networks. We also initialize the congestion/slow start
+ * window. While looking at the routing entry, we also initialize
+ * other path-dependent parameters from pre-set or cached values
+ * in the routing entry.
+ *
+ * Also take into account the space needed for options that we
+ * send regularly. Make maxseg shorter by that amount to assure
+ * that we can send maxseg amount of data even when the options
+ * are present. Store the upper limit of the length of options plus
+ * data in maxopd.
+ *
+ * NOTE that this routine is only called when we process an incoming
+ * segment, for outgoing segments only tcp_mssopt is called.
+ *
+ */
+void
+tcp_mss(struct tcpcb *tp, int offer, unsigned int input_ifscope)
+{
+ struct rtentry *rt;
+ struct ifnet *ifp;
+ int rtt, mss;
+ u_int32_t bufsize;
+ struct inpcb *inp;
+ struct socket *so;
+ struct rmxp_tao *taop;
+ int origoffer = offer;
+ u_int32_t sb_max_corrected;
+ int isnetlocal = 0;
+#if INET6
+ int isipv6;
+ int min_protoh;
+#endif
- /*
- * In CLOSING STATE in addition to the processing for
- * the ESTABLISHED state if the ACK acknowledges our FIN
- * then enter the TIME-WAIT state, otherwise ignore
- * the segment.
- */
- case TCPS_CLOSING:
- if (ourfinisacked) {
- tp->t_state = TCPS_TIME_WAIT;
- tcp_canceltimers(tp);
- /* Shorten TIME_WAIT [RFC-1644, p.28] */
- if (tp->cc_recv != 0 &&
- tp->t_duration < TCPTV_MSL)
- tp->t_timer[TCPT_2MSL] =
- tp->t_rxtcur * TCPTV_TWTRUNC;
- else
- tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
- add_to_time_wait(tp);
- current_active_connections--;
- soisdisconnected(so);
- }
- break;
+ inp = tp->t_inpcb;
- /*
- * In LAST_ACK, we may still be waiting for data to drain
- * and/or to be acked, as well as for the ack of our FIN.
- * If our FIN is now acknowledged, delete the TCB,
- * enter the closed state and return.
- */
- case TCPS_LAST_ACK:
- if (ourfinisacked) {
- tp = tcp_close(tp);
- goto drop;
- }
- break;
+ so = inp->inp_socket;
+ /*
+ * Nothing left to send after the socket is defunct or TCP is in the closed state
+ */
+ if ((so->so_state & SS_DEFUNCT) || tp->t_state == TCPS_CLOSED) {
+ return;
+ }
- /*
- * In TIME_WAIT state the only thing that should arrive
- * is a retransmission of the remote FIN. Acknowledge
- * it and restart the finack timer.
- */
- case TCPS_TIME_WAIT:
- tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
- add_to_time_wait(tp);
- goto dropafterack;
- }
+#if INET6
+ isipv6 = ((inp->inp_vflag & INP_IPV6) != 0) ? 1 : 0;
+ min_protoh = isipv6 ? sizeof(struct ip6_hdr) + sizeof(struct tcphdr)
+ : sizeof(struct tcpiphdr);
+#else
+#define min_protoh (sizeof (struct tcpiphdr))
+#endif
+
+#if INET6
+ if (isipv6) {
+ rt = tcp_rtlookup6(inp, input_ifscope);
+ } else
+#endif /* INET6 */
+ {
+ rt = tcp_rtlookup(inp, input_ifscope);
}
+ isnetlocal = (tp->t_flags & TF_LOCAL);
-step6:
+ if (rt == NULL) {
+ tp->t_maxopd = tp->t_maxseg =
+#if INET6
+ isipv6 ? tcp_v6mssdflt :
+#endif /* INET6 */
+ tcp_mssdflt;
+ return;
+ }
+ ifp = rt->rt_ifp;
/*
- * Update window information.
- * Don't look at window if no ACK: TAC's send garbage on first SYN.
+ * Slower link window correction:
+ * If a value is specificied for slowlink_wsize use it for
+ * PPP links believed to be on a serial modem (speed <128Kbps).
+ * Excludes 9600bps as it is the default value adversized
+ * by pseudo-devices over ppp.
*/
- if ((thflags & TH_ACK) &&
- (SEQ_LT(tp->snd_wl1, th->th_seq) ||
- (tp->snd_wl1 == th->th_seq && (SEQ_LT(tp->snd_wl2, th->th_ack) ||
- (tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd))))) {
- /* keep track of pure window updates */
- if (tilen == 0 &&
- tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd)
- tcpstat.tcps_rcvwinupd++;
- tp->snd_wnd = tiwin;
- tp->snd_wl1 = th->th_seq;
- tp->snd_wl2 = th->th_ack;
- if (tp->snd_wnd > tp->max_sndwnd)
- tp->max_sndwnd = tp->snd_wnd;
- needoutput = 1;
+ if (ifp->if_type == IFT_PPP && slowlink_wsize > 0 &&
+ ifp->if_baudrate > 9600 && ifp->if_baudrate <= 128000) {
+ tp->t_flags |= TF_SLOWLINK;
}
+ taop = rmx_taop(rt->rt_rmx);
/*
- * Process segments with URG.
+ * Offer == -1 means that we didn't receive SYN yet,
+ * use cached value in that case;
*/
- if ((thflags & TH_URG) && th->th_urp &&
- TCPS_HAVERCVDFIN(tp->t_state) == 0) {
+ if (offer == -1) {
+ offer = taop->tao_mssopt;
+ }
+ /*
+ * Offer == 0 means that there was no MSS on the SYN segment,
+ * in this case we use tcp_mssdflt.
+ */
+ if (offer == 0) {
+ offer =
+#if INET6
+ isipv6 ? tcp_v6mssdflt :
+#endif /* INET6 */
+ tcp_mssdflt;
+ } else {
/*
- * This is a kludge, but if we receive and accept
- * random urgent pointers, we'll crash in
- * soreceive. It's hard to imagine someone
- * actually wanting to send this much urgent data.
+ * Prevent DoS attack with too small MSS. Round up
+ * to at least minmss.
*/
- if (th->th_urp + so->so_rcv.sb_cc > sb_max) {
- th->th_urp = 0; /* XXX */
- thflags &= ~TH_URG; /* XXX */
- goto dodata; /* XXX */
- }
+ offer = max(offer, tcp_minmss);
/*
- * If this segment advances the known urgent pointer,
- * then mark the data stream. This should not happen
- * in CLOSE_WAIT, CLOSING, LAST_ACK or TIME_WAIT STATES since
- * a FIN has been received from the remote side.
- * In these states we ignore the URG.
- *
- * According to RFC961 (Assigned Protocols),
- * the urgent pointer points to the last octet
- * of urgent data. We continue, however,
- * to consider it to indicate the first octet
- * of data past the urgent section as the original
- * spec states (in one of two places).
+ * Sanity check: make sure that maxopd will be large
+ * enough to allow some data on segments even is the
+ * all the option space is used (40bytes). Otherwise
+ * funny things may happen in tcp_output.
*/
- if (SEQ_GT(th->th_seq+th->th_urp, tp->rcv_up)) {
- tp->rcv_up = th->th_seq + th->th_urp;
- so->so_oobmark = so->so_rcv.sb_cc +
- (tp->rcv_up - tp->rcv_nxt) - 1;
- if (so->so_oobmark == 0) {
- so->so_state |= SS_RCVATMARK;
- postevent(so, 0, EV_OOB);
+ offer = max(offer, 64);
+ }
+ taop->tao_mssopt = offer;
+
+ /*
+ * While we're here, check if there's an initial rtt
+ * or rttvar. Convert from the route-table units
+ * to scaled multiples of the slow timeout timer.
+ */
+ if (tp->t_srtt == 0 && (rtt = rt->rt_rmx.rmx_rtt) != 0) {
+ tcp_getrt_rtt(tp, rt);
+ } else {
+ tp->t_rttmin = isnetlocal ? tcp_TCPTV_MIN : TCPTV_REXMTMIN;
+ }
+
+#if INET6
+ mss = (isipv6 ? tcp_maxmtu6(rt) : tcp_maxmtu(rt));
+#else
+ mss = tcp_maxmtu(rt);
+#endif
+
+#if NECP
+ // At this point, the mss is just the MTU. Adjust if necessary.
+ mss = necp_socket_get_effective_mtu(inp, mss);
+#endif /* NECP */
+
+ mss -= min_protoh;
+
+ if (rt->rt_rmx.rmx_mtu == 0) {
+#if INET6
+ if (isipv6) {
+ if (!isnetlocal) {
+ mss = min(mss, tcp_v6mssdflt);
}
- sohasoutofband(so);
- tp->t_oobflags &= ~(TCPOOB_HAVEDATA | TCPOOB_HADDATA);
+ } else
+#endif /* INET6 */
+ if (!isnetlocal) {
+ mss = min(mss, tcp_mssdflt);
}
- /*
- * Remove out of band data so doesn't get presented to user.
- * This can happen independent of advancing the URG pointer,
- * but if two URG's are pending at once, some out-of-band
- * data may creep in... ick.
- */
- if (th->th_urp <= (u_long)tilen
-#if SO_OOBINLINE
- && (so->so_options & SO_OOBINLINE) == 0
-#endif
- )
- tcp_pulloutofband(so, th, m);
- } else
- /*
- * If no out of band data is expected,
- * pull receive urgent pointer along
- * with the receive window.
- */
- if (SEQ_GT(tp->rcv_nxt, tp->rcv_up))
- tp->rcv_up = tp->rcv_nxt;
-dodata: /* XXX */
+ }
+ mss = min(mss, offer);
/*
- * Process the segment text, merging it into the TCP sequencing queue,
- * and arranging for acknowledgment of receipt if necessary.
- * This process logically involves adjusting tp->rcv_wnd as data
- * is presented to the user (this happens in tcp_usrreq.c,
- * case PRU_RCVD). If a FIN has already been received on this
- * connection then we just ignore the text.
+ * maxopd stores the maximum length of data AND options
+ * in a segment; maxseg is the amount of data in a normal
+ * segment. We need to store this value (maxopd) apart
+ * from maxseg, because now every segment carries options
+ * and thus we normally have somewhat less data in segments.
*/
- if ((tilen || (thflags&TH_FIN)) &&
- TCPS_HAVERCVDFIN(tp->t_state) == 0) {
- TCP_REASS(tp, th, tilen, m, so, thflags, isipv6, need_sorwakeup);
+ tp->t_maxopd = mss;
- if (tp->t_flags & TF_DELACK)
- {
- KERNEL_DEBUG(DBG_LAYER_END, ((th->th_dport << 16) | th->th_sport),
- (((th->th_src.s_addr & 0xffff) << 16) | (th->th_dst.s_addr & 0xffff)),
- th->th_seq, th->th_ack, th->th_win);
- }
- /*
- * Note the amount of data that peer has sent into
- * our window, in order to estimate the sender's
- * buffer size.
- */
- len = so->so_rcv.sb_hiwat - (tp->rcv_adv - tp->rcv_nxt);
- } else {
- m_freem(m);
- thflags &= ~TH_FIN;
+ /*
+ * origoffer==-1 indicates, that no segments were received yet.
+ * In this case we just guess.
+ */
+ if ((tp->t_flags & (TF_REQ_TSTMP | TF_NOOPT)) == TF_REQ_TSTMP &&
+ (origoffer == -1 ||
+ (tp->t_flags & TF_RCVD_TSTMP) == TF_RCVD_TSTMP)) {
+ mss -= TCPOLEN_TSTAMP_APPA;
}
+#if MPTCP
+ mss -= mptcp_adj_mss(tp, FALSE);
+#endif /* MPTCP */
+ tp->t_maxseg = mss;
+
/*
- * If FIN is received ACK the FIN and let the user know
- * that the connection is closing.
+ * Calculate corrected value for sb_max; ensure to upgrade the
+ * numerator for large sb_max values else it will overflow.
*/
- if (thflags & TH_FIN) {
- if (TCPS_HAVERCVDFIN(tp->t_state) == 0) {
- socantrcvmore(so);
- postevent(so, 0, EV_FIN);
- /*
- * If connection is half-synchronized
- * (ie NEEDSYN flag on) then delay ACK,
- * so it may be piggybacked when SYN is sent.
- * Otherwise, since we received a FIN then no
- * more input can be expected, send ACK now.
- */
- if (tcp_delack_enabled && (tp->t_flags & TF_NEEDSYN)) {
- if (last_active_conn_count > DELACK_BITMASK_THRESH)
- TCP_DELACK_BITSET(tp->t_inpcb->hash_element);
+ sb_max_corrected = (sb_max * (u_int64_t)MCLBYTES) / (MSIZE + MCLBYTES);
- tp->t_flags |= TF_DELACK;
- }
- else
- tp->t_flags |= TF_ACKNOW;
- tp->rcv_nxt++;
+ /*
+ * If there's a pipesize (ie loopback), change the socket
+ * buffer to that size only if it's bigger than the current
+ * sockbuf size. Make the socket buffers an integral
+ * number of mss units; if the mss is larger than
+ * the socket buffer, decrease the mss.
+ */
+#if RTV_SPIPE
+ bufsize = rt->rt_rmx.rmx_sendpipe;
+ if (bufsize < so->so_snd.sb_hiwat)
+#endif
+ bufsize = so->so_snd.sb_hiwat;
+ if (bufsize < mss) {
+ mss = bufsize;
+ } else {
+ bufsize = (((bufsize + (u_int64_t)mss - 1) / (u_int64_t)mss) * (u_int64_t)mss);
+ if (bufsize > sb_max_corrected) {
+ bufsize = sb_max_corrected;
}
- switch (tp->t_state) {
+ (void)sbreserve(&so->so_snd, bufsize);
+ }
+ tp->t_maxseg = mss;
- /*
- * In SYN_RECEIVED and ESTABLISHED STATES
- * enter the CLOSE_WAIT state.
- */
- case TCPS_SYN_RECEIVED:
- case TCPS_ESTABLISHED:
- tp->t_state = TCPS_CLOSE_WAIT;
- break;
+ ASSERT(tp->t_maxseg);
- /*
- * If still in FIN_WAIT_1 STATE FIN has not been acked so
- * enter the CLOSING state.
- */
- case TCPS_FIN_WAIT_1:
- tp->t_state = TCPS_CLOSING;
- break;
+ /*
+ * Update MSS using recommendation from link status report. This is
+ * temporary
+ */
+ tcp_update_mss_locked(so, ifp);
- /*
- * In FIN_WAIT_2 state enter the TIME_WAIT state,
- * starting the time-wait timer, turning off the other
- * standard timers.
- */
- case TCPS_FIN_WAIT_2:
- tp->t_state = TCPS_TIME_WAIT;
- tcp_canceltimers(tp);
- /* Shorten TIME_WAIT [RFC-1644, p.28] */
- if (tp->cc_recv != 0 &&
- tp->t_duration < TCPTV_MSL) {
- tp->t_timer[TCPT_2MSL] =
- tp->t_rxtcur * TCPTV_TWTRUNC;
- /* For transaction client, force ACK now. */
- tp->t_flags |= TF_ACKNOW;
- }
- else
- tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
+#if RTV_RPIPE
+ bufsize = rt->rt_rmx.rmx_recvpipe;
+ if (bufsize < so->so_rcv.sb_hiwat)
+#endif
+ bufsize = so->so_rcv.sb_hiwat;
+ if (bufsize > mss) {
+ bufsize = (((bufsize + (u_int64_t)mss - 1) / (u_int64_t)mss) * (u_int64_t)mss);
+ if (bufsize > sb_max_corrected) {
+ bufsize = sb_max_corrected;
+ }
+ (void)sbreserve(&so->so_rcv, bufsize);
+ }
- add_to_time_wait(tp);
- soisdisconnected(so);
- break;
+ set_tcp_stream_priority(so);
+ if (rt->rt_rmx.rmx_ssthresh) {
/*
- * In TIME_WAIT state restart the 2 MSL time_wait timer.
+ * There's some sort of gateway or interface
+ * buffer limit on the path. Use this to set
+ * slow-start threshold, but set the threshold to
+ * no less than 2*mss.
*/
- case TCPS_TIME_WAIT:
- tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
- add_to_time_wait(tp);
- break;
- }
- }
-#if TCPDEBUG
- if (so->so_options & SO_DEBUG) {
-#if INET6
- if (isipv6)
- tcp_saveip._tcp_si6.ip6_plen = tilen;
- else
- tcp_saveip._tcp_si4.ip_len = tilen;
-#else /* INET6 */
- tcp_saveip.ip_len = tilen;
-#endif /* INET6 */
-
- tcp_trace(TA_INPUT, ostate, tp, (void *)&tcp_saveip,
- &tcp_savetcp, 0);
+ tp->snd_ssthresh = max(2 * mss, rt->rt_rmx.rmx_ssthresh);
+ tcpstat.tcps_usedssthresh++;
+ } else {
+ tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
}
-#endif
/*
- * Return any desired output.
+ * Set the slow-start flight size depending on whether this
+ * is a local network or not.
*/
- if (needoutput || (tp->t_flags & TF_ACKNOW))
- (void) tcp_output(tp);
- if (need_sorwakeup)
- sorwakeup(so);
- if (need_sowwakeup)
- sowwakeup(so);
- KERNEL_DEBUG(DBG_FNC_TCP_INPUT | DBG_FUNC_END,0,0,0,0,0);
- return;
+ if (CC_ALGO(tp)->cwnd_init != NULL) {
+ CC_ALGO(tp)->cwnd_init(tp);
+ }
-dropafterack:
- /*
- * Generate an ACK dropping incoming segment if it occupies
- * sequence space, where the ACK reflects our state.
- *
- * We can now skip the test for the RST flag since all
- * paths to this code happen after packets containing
- * RST have been dropped.
- *
- * In the SYN-RECEIVED state, don't send an ACK unless the
- * segment we received passes the SYN-RECEIVED ACK test.
- * If it fails send a RST. This breaks the loop in the
- * "LAND" DoS attack, and also prevents an ACK storm
- * between two listening ports that have been sent forged
- * SYN segments, each with the source address of the other.
- */
- if (tp->t_state == TCPS_SYN_RECEIVED && (thflags & TH_ACK) &&
- (SEQ_GT(tp->snd_una, th->th_ack) ||
- SEQ_GT(th->th_ack, tp->snd_max)) )
- goto dropwithreset;
-#if TCPDEBUG
- if (so->so_options & SO_DEBUG) {
+ tcp_ccdbg_trace(tp, NULL, TCP_CC_CWND_INIT);
+
+ /* Route locked during lookup above */
+ RT_UNLOCK(rt);
+}
+
+/*
+ * Determine the MSS option to send on an outgoing SYN.
+ */
+int
+tcp_mssopt(struct tcpcb *tp)
+{
+ struct rtentry *rt;
+ int mss;
#if INET6
- if (isipv6)
- tcp_saveip._tcp_si6.ip6_plen = tilen;
- else
- tcp_saveip._tcp_si4.ip_len = tilen;
-#else /* INET6 */
- tcp_saveip.ip_len = tilen;
-#endif /* INET6 */
- tcp_trace(TA_DROP, ostate, tp, (void *)&tcp_saveip,
- &tcp_savetcp, 0);
- }
+ int isipv6;
+ int min_protoh;
#endif
- m_freem(m);
- tp->t_flags |= TF_ACKNOW;
- (void) tcp_output(tp);
- if (need_sorwakeup)
- sorwakeup(so);
- if (need_sowwakeup)
- sowwakeup(so);
- KERNEL_DEBUG(DBG_FNC_TCP_INPUT | DBG_FUNC_END,0,0,0,0,0);
- return;
-dropwithreset:
- /*
- * Generate a RST, dropping incoming segment.
- * Make ACK acceptable to originator of segment.
- * Don't bother to respond if destination was broadcast/multicast.
- */
- if ((thflags & TH_RST) || m->m_flags & (M_BCAST|M_MCAST))
- goto drop;
-#if INET6
- if (isipv6) {
- if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst))
- goto drop; /* anycast check is done at the top */
- } else
-#endif /* INET6 */
- if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr)))
- goto drop;
-#if TCPDEBUG
- if (tp == 0 || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) {
- if (tp == 0) {
-#if INET6
- if (isipv6)
- tcp_saveip._tcp_si6 = *ip6;
- else
- tcp_saveip._tcp_si4 = *ip;
-#else /* INET6 */
- tcp_saveip = *ip;
-#endif /* INET6 */
- }
#if INET6
- if (isipv6)
- tcp_saveip._tcp_si6.ip6_plen = tilen;
- else
- tcp_saveip._tcp_si4.ip_len = tilen;
-#else /* INET6 */
- tcp_saveip.ip_len = tilen;
-#endif /* INET6 */
- tcp_trace(TA_DROP, ostate, tp, (void *)&tcp_saveip,
- &tcp_savetcp, 0);
- }
+ isipv6 = ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) ? 1 : 0;
+ min_protoh = isipv6 ? sizeof(struct ip6_hdr) + sizeof(struct tcphdr)
+ : sizeof(struct tcpiphdr);
+#else
+#define min_protoh (sizeof (struct tcpiphdr))
#endif
- if (thflags & TH_ACK)
+
#if INET6
- tcp_respond(tp, isipv6 ? (void *)ip6 : (void *)ip, th, m,
- (tcp_seq)0, th->th_ack, TH_RST, isipv6);
-#else /* INET6 */
- tcp_respond(tp, (void *)ip, th, m,
- (tcp_seq)0, th->th_ack, TH_RST, isipv6);
+ if (isipv6) {
+ rt = tcp_rtlookup6(tp->t_inpcb, IFSCOPE_NONE);
+ } else
#endif /* INET6 */
- else {
- if (thflags & TH_SYN)
- tilen++;
+ rt = tcp_rtlookup(tp->t_inpcb, IFSCOPE_NONE);
+ if (rt == NULL) {
+ return
#if INET6
- tcp_respond(tp, isipv6 ? (void *)ip6 : (void *)ip, th, m,
- th->th_seq+tilen, (tcp_seq)0, TH_RST|TH_ACK,
- isipv6);
-#else /* INET6 */
- tcp_respond(tp, (void *)ip, th, m,
- th->th_seq+tilen, (tcp_seq)0, TH_RST|TH_ACK,
- isipv6);
+ isipv6 ? tcp_v6mssdflt :
#endif /* INET6 */
+ tcp_mssdflt;
}
- /* destroy temporarily created socket */
- if (need_sorwakeup)
- sorwakeup(so);
- if (need_sowwakeup)
- sowwakeup(so);
- if (dropsocket)
- (void) soabort(so);
- KERNEL_DEBUG(DBG_FNC_TCP_INPUT | DBG_FUNC_END,0,0,0,0,0);
- return;
-
-drop:
/*
- * Drop space held by incoming segment and return.
+ * Slower link window correction:
+ * If a value is specificied for slowlink_wsize use it for PPP links
+ * believed to be on a serial modem (speed <128Kbps). Excludes 9600bps as
+ * it is the default value adversized by pseudo-devices over ppp.
*/
-#if TCPDEBUG
- if (tp == 0 || (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) {
- if (tp == 0) {
-#if INET6
- if (isipv6)
- tcp_saveip._tcp_si6 = *ip6;
- else
- tcp_saveip._tcp_si4 = *ip;
-#else /* INET6 */
- tcp_saveip = *ip;
-#endif /* INET6 */
- }
-#if INET6
- if (isipv6)
- tcp_saveip._tcp_si6.ip6_plen = tilen;
- else
- tcp_saveip._tcp_si4.ip_len = tilen;
-#else /* INET6 */
- tcp_saveip.ip_len = tilen;
-#endif /* INET6 */
- tcp_trace(TA_DROP, ostate, tp, (void *)&tcp_saveip,
- &tcp_savetcp, 0);
+ if (rt->rt_ifp->if_type == IFT_PPP && slowlink_wsize > 0 &&
+ rt->rt_ifp->if_baudrate > 9600 && rt->rt_ifp->if_baudrate <= 128000) {
+ tp->t_flags |= TF_SLOWLINK;
}
+
+#if INET6
+ mss = (isipv6 ? tcp_maxmtu6(rt) : tcp_maxmtu(rt));
+#else
+ mss = tcp_maxmtu(rt);
#endif
- m_freem(m);
- if (need_sorwakeup)
- sorwakeup(so);
- if (need_sowwakeup)
- sowwakeup(so);
- /* destroy temporarily created socket */
- if (dropsocket)
- (void) soabort(so);
- KERNEL_DEBUG(DBG_FNC_TCP_INPUT | DBG_FUNC_END,0,0,0,0,0);
- return;
+ /* Route locked during lookup above */
+ RT_UNLOCK(rt);
+
+#if NECP
+ // At this point, the mss is just the MTU. Adjust if necessary.
+ mss = necp_socket_get_effective_mtu(tp->t_inpcb, mss);
+#endif /* NECP */
+
+ return mss - min_protoh;
}
+/*
+ * On a partial ack arrives, force the retransmission of the
+ * next unacknowledged segment. Do not clear tp->t_dupacks.
+ * By setting snd_nxt to th_ack, this forces retransmission timer to
+ * be started again.
+ */
static void
-tcp_dooptions(tp, cp, cnt, th, to)
- struct tcpcb *tp;
- u_char *cp;
- int cnt;
- struct tcphdr *th;
- struct tcpopt *to;
+tcp_newreno_partial_ack(struct tcpcb *tp, struct tcphdr *th)
{
- u_short mss = 0;
- int opt, optlen;
-
- for (; cnt > 0; cnt -= optlen, cp += optlen) {
- opt = cp[0];
- if (opt == TCPOPT_EOL)
- break;
- if (opt == TCPOPT_NOP)
- optlen = 1;
- else {
- optlen = cp[1];
- if (optlen <= 0)
- break;
- }
- switch (opt) {
+ tcp_seq onxt = tp->snd_nxt;
+ u_int32_t ocwnd = tp->snd_cwnd;
+ tp->t_timer[TCPT_REXMT] = 0;
+ tp->t_timer[TCPT_PTO] = 0;
+ tp->t_rtttime = 0;
+ tp->snd_nxt = th->th_ack;
+ /*
+ * Set snd_cwnd to one segment beyond acknowledged offset
+ * (tp->snd_una has not yet been updated when this function
+ * is called)
+ */
+ tp->snd_cwnd = tp->t_maxseg + BYTES_ACKED(th, tp);
+ tp->t_flags |= TF_ACKNOW;
+ (void) tcp_output(tp);
+ tp->snd_cwnd = ocwnd;
+ if (SEQ_GT(onxt, tp->snd_nxt)) {
+ tp->snd_nxt = onxt;
+ }
+ /*
+ * Partial window deflation. Relies on fact that tp->snd_una
+ * not updated yet.
+ */
+ if (tp->snd_cwnd > BYTES_ACKED(th, tp)) {
+ tp->snd_cwnd -= BYTES_ACKED(th, tp);
+ } else {
+ tp->snd_cwnd = 0;
+ }
+ tp->snd_cwnd += tp->t_maxseg;
+}
- default:
- continue;
+/*
+ * Drop a random TCP connection that hasn't been serviced yet and
+ * is eligible for discard. There is a one in qlen chance that
+ * we will return a null, saying that there are no dropable
+ * requests. In this case, the protocol specific code should drop
+ * the new request. This insures fairness.
+ *
+ * The listening TCP socket "head" must be locked
+ */
+static int
+tcp_dropdropablreq(struct socket *head)
+{
+ struct socket *so, *sonext;
+ unsigned int i, j, qlen;
+ static u_int32_t rnd = 0;
+ static u_int64_t old_runtime;
+ static unsigned int cur_cnt, old_cnt;
+ u_int64_t now_sec;
+ struct inpcb *inp = NULL;
+ struct tcpcb *tp;
- case TCPOPT_MAXSEG:
- if (optlen != TCPOLEN_MAXSEG)
- continue;
- if (!(th->th_flags & TH_SYN))
- continue;
- bcopy((char *) cp + 2, (char *) &mss, sizeof(mss));
- to->to_maxseg = ntohs(mss);
- break;
+ if ((head->so_options & SO_ACCEPTCONN) == 0) {
+ return 0;
+ }
- case TCPOPT_WINDOW:
- if (optlen != TCPOLEN_WINDOW)
- continue;
- if (!(th->th_flags & TH_SYN))
- continue;
- tp->t_flags |= TF_RCVD_SCALE;
- tp->requested_s_scale = min(cp[2], TCP_MAX_WINSHIFT);
- break;
+ if (TAILQ_EMPTY(&head->so_incomp)) {
+ return 0;
+ }
- case TCPOPT_TIMESTAMP:
- if (optlen != TCPOLEN_TIMESTAMP)
- continue;
- to->to_flag |= TOF_TS;
- bcopy((char *)cp + 2,
- (char *)&to->to_tsval, sizeof(to->to_tsval));
- NTOHL(to->to_tsval);
- bcopy((char *)cp + 6,
- (char *)&to->to_tsecr, sizeof(to->to_tsecr));
- NTOHL(to->to_tsecr);
+ so_acquire_accept_list(head, NULL);
+ socket_unlock(head, 0);
+ /*
+ * Check if there is any socket in the incomp queue
+ * that is closed because of a reset from the peer and is
+ * waiting to be garbage collected. If so, pick that as
+ * the victim
+ */
+ TAILQ_FOREACH_SAFE(so, &head->so_incomp, so_list, sonext) {
+ inp = sotoinpcb(so);
+ tp = intotcpcb(inp);
+ if (tp != NULL && tp->t_state == TCPS_CLOSED &&
+ so->so_head != NULL &&
+ (so->so_state & (SS_INCOMP | SS_CANTSENDMORE | SS_CANTRCVMORE)) ==
+ (SS_INCOMP | SS_CANTSENDMORE | SS_CANTRCVMORE)) {
/*
- * A timestamp received in a SYN makes
- * it ok to send timestamp requests and replies.
- */
- if (th->th_flags & TH_SYN) {
- tp->t_flags |= TF_RCVD_TSTMP;
- tp->ts_recent = to->to_tsval;
- tp->ts_recent_age = tcp_now;
- }
- break;
- case TCPOPT_CC:
- if (optlen != TCPOLEN_CC)
- continue;
- to->to_flag |= TOF_CC;
- bcopy((char *)cp + 2,
- (char *)&to->to_cc, sizeof(to->to_cc));
- NTOHL(to->to_cc);
- /*
- * A CC or CC.new option received in a SYN makes
- * it ok to send CC in subsequent segments.
- */
- if (th->th_flags & TH_SYN)
- tp->t_flags |= TF_RCVD_CC;
- break;
- case TCPOPT_CCNEW:
- if (optlen != TCPOLEN_CC)
- continue;
- if (!(th->th_flags & TH_SYN))
- continue;
- to->to_flag |= TOF_CCNEW;
- bcopy((char *)cp + 2,
- (char *)&to->to_cc, sizeof(to->to_cc));
- NTOHL(to->to_cc);
- /*
- * A CC or CC.new option received in a SYN makes
- * it ok to send CC in subsequent segments.
+ * The listen socket is already locked but we
+ * can lock this socket here without lock ordering
+ * issues because it is in the incomp queue and
+ * is not visible to others.
*/
- tp->t_flags |= TF_RCVD_CC;
- break;
- case TCPOPT_CCECHO:
- if (optlen != TCPOLEN_CC)
- continue;
- if (!(th->th_flags & TH_SYN))
+ if (socket_try_lock(so)) {
+ so->so_usecount++;
+ goto found_victim;
+ } else {
continue;
- to->to_flag |= TOF_CCECHO;
- bcopy((char *)cp + 2,
- (char *)&to->to_ccecho, sizeof(to->to_ccecho));
- NTOHL(to->to_ccecho);
- break;
+ }
}
}
-}
-/*
- * Pull out of band byte out of a segment so
- * it doesn't appear in the user's data queue.
- * It is still reflected in the segment length for
- * sequencing purposes.
- */
-static void
-tcp_pulloutofband(so, th, m)
- struct socket *so;
- struct tcphdr *th;
- register struct mbuf *m;
-{
- int cnt = th->th_urp - 1;
+ so = TAILQ_FIRST(&head->so_incomp);
- while (cnt >= 0) {
- if (m->m_len > cnt) {
- char *cp = mtod(m, caddr_t) + cnt;
- struct tcpcb *tp = sototcpcb(so);
+ now_sec = net_uptime();
+ if ((i = (now_sec - old_runtime)) != 0) {
+ old_runtime = now_sec;
+ old_cnt = cur_cnt / i;
+ cur_cnt = 0;
+ }
- tp->t_iobc = *cp;
- tp->t_oobflags |= TCPOOB_HAVEDATA;
- bcopy(cp+1, cp, (unsigned)(m->m_len - cnt - 1));
- m->m_len--;
- return;
+ qlen = head->so_incqlen;
+ if (rnd == 0) {
+ rnd = RandomULong();
+ }
+
+ if (++cur_cnt > qlen || old_cnt > qlen) {
+ rnd = (314159 * rnd + 66329) & 0xffff;
+ j = ((qlen + 1) * rnd) >> 16;
+
+ while (j-- && so) {
+ so = TAILQ_NEXT(so, so_list);
}
- cnt -= m->m_len;
- m = m->m_next;
- if (m == 0)
- break;
}
- panic("tcp_pulloutofband");
-}
+ /* Find a connection that is not already closing (or being served) */
+ while (so) {
+ inp = (struct inpcb *)so->so_pcb;
-/*
- * Collect new round-trip time estimate
- * and update averages and current timeout.
- */
-static void
-tcp_xmit_timer(tp, rtt)
- register struct tcpcb *tp;
- short rtt;
-{
- register int delta;
+ sonext = TAILQ_NEXT(so, so_list);
- tcpstat.tcps_rttupdated++;
- tp->t_rttupdated++;
- if (tp->t_srtt != 0) {
- /*
- * srtt is stored as fixed point with 5 bits after the
- * binary point (i.e., scaled by 8). The following magic
- * is equivalent to the smoothing algorithm in rfc793 with
- * an alpha of .875 (srtt = rtt/8 + srtt*7/8 in fixed
- * point). Adjust rtt to origin 0.
- */
- delta = ((rtt - 1) << TCP_DELTA_SHIFT)
- - (tp->t_srtt >> (TCP_RTT_SHIFT - TCP_DELTA_SHIFT));
+ if (in_pcb_checkstate(inp, WNT_ACQUIRE, 0) != WNT_STOPUSING) {
+ /*
+ * Avoid the issue of a socket being accepted
+ * by one input thread and being dropped by
+ * another input thread. If we can't get a hold
+ * on this mutex, then grab the next socket in
+ * line.
+ */
+ if (socket_try_lock(so)) {
+ so->so_usecount++;
+ if ((so->so_usecount == 2) &&
+ (so->so_state & SS_INCOMP) &&
+ !(so->so_flags & SOF_INCOMP_INPROGRESS)) {
+ break;
+ } else {
+ /*
+ * don't use if being accepted or
+ * used in any other way
+ */
+ in_pcb_checkstate(inp, WNT_RELEASE, 1);
+ socket_unlock(so, 1);
+ }
+ } else {
+ /*
+ * do not try to lock the inp in
+ * in_pcb_checkstate because the lock
+ * is already held in some other thread.
+ * Only drop the inp_wntcnt reference.
+ */
+ in_pcb_checkstate(inp, WNT_RELEASE, 1);
+ }
+ }
+ so = sonext;
+ }
+ if (so == NULL) {
+ socket_lock(head, 0);
+ so_release_accept_list(head);
+ return 0;
+ }
- if ((tp->t_srtt += delta) <= 0)
- tp->t_srtt = 1;
+ /* Makes sure socket is still in the right state to be discarded */
+
+ if (in_pcb_checkstate(inp, WNT_RELEASE, 1) == WNT_STOPUSING) {
+ socket_unlock(so, 1);
+ socket_lock(head, 0);
+ so_release_accept_list(head);
+ return 0;
+ }
+
+found_victim:
+ if (so->so_usecount != 2 || !(so->so_state & SS_INCOMP)) {
+ /* do not discard: that socket is being accepted */
+ socket_unlock(so, 1);
+ socket_lock(head, 0);
+ so_release_accept_list(head);
+ return 0;
+ }
+ socket_lock(head, 0);
+ TAILQ_REMOVE(&head->so_incomp, so, so_list);
+ head->so_incqlen--;
+ head->so_qlen--;
+ so->so_state &= ~SS_INCOMP;
+ so->so_flags |= SOF_OVERFLOW;
+ so->so_head = NULL;
+ so_release_accept_list(head);
+ socket_unlock(head, 0);
+
+ socket_lock_assert_owned(so);
+ tp = sototcpcb(so);
+
+ tcp_close(tp);
+ if (inp->inp_wantcnt > 0 && inp->inp_wantcnt != WNT_STOPUSING) {
/*
- * We accumulate a smoothed rtt variance (actually, a
- * smoothed mean difference), then set the retransmit
- * timer to smoothed rtt + 4 times the smoothed variance.
- * rttvar is stored as fixed point with 4 bits after the
- * binary point (scaled by 16). The following is
- * equivalent to rfc793 smoothing with an alpha of .75
- * (rttvar = rttvar*3/4 + |delta| / 4). This replaces
- * rfc793's wired-in beta.
+ * Some one has a wantcnt on this pcb. Since WNT_ACQUIRE
+ * doesn't require a lock, it could have happened while
+ * we are holding the lock. This pcb will have to
+ * be garbage collected later.
+ * Release the reference held for so_incomp queue
*/
- if (delta < 0)
- delta = -delta;
- delta -= tp->t_rttvar >> (TCP_RTTVAR_SHIFT - TCP_DELTA_SHIFT);
- if ((tp->t_rttvar += delta) <= 0)
- tp->t_rttvar = 1;
+ VERIFY(so->so_usecount > 0);
+ so->so_usecount--;
+ socket_unlock(so, 1);
+ } else {
+ /*
+ * Unlock this socket and leave the reference on.
+ * We need to acquire the pcbinfo lock in order to
+ * fully dispose it off
+ */
+ socket_unlock(so, 0);
+
+ lck_rw_lock_exclusive(tcbinfo.ipi_lock);
+
+ socket_lock(so, 0);
+ /* Release the reference held for so_incomp queue */
+ VERIFY(so->so_usecount > 0);
+ so->so_usecount--;
+
+ if (so->so_usecount != 1 ||
+ (inp->inp_wantcnt > 0 &&
+ inp->inp_wantcnt != WNT_STOPUSING)) {
+ /*
+ * There is an extra wantcount or usecount
+ * that must have been added when the socket
+ * was unlocked. This socket will have to be
+ * garbage collected later
+ */
+ socket_unlock(so, 1);
+ } else {
+ /* Drop the reference held for this function */
+ VERIFY(so->so_usecount > 0);
+ so->so_usecount--;
+
+ in_pcbdispose(inp);
+ }
+ lck_rw_done(tcbinfo.ipi_lock);
+ }
+ tcpstat.tcps_drops++;
+
+ socket_lock(head, 0);
+ return 1;
+}
+
+/* Set background congestion control on a socket */
+void
+tcp_set_background_cc(struct socket *so)
+{
+ tcp_set_new_cc(so, TCP_CC_ALGO_BACKGROUND_INDEX);
+}
+
+/* Set foreground congestion control on a socket */
+void
+tcp_set_foreground_cc(struct socket *so)
+{
+ if (tcp_use_newreno) {
+ tcp_set_new_cc(so, TCP_CC_ALGO_NEWRENO_INDEX);
} else {
- /*
- * No rtt measurement yet - use the unsmoothed rtt.
- * Set the variance to half the rtt (so our first
- * retransmit happens at 3*rtt).
- */
- tp->t_srtt = rtt << TCP_RTT_SHIFT;
- tp->t_rttvar = rtt << (TCP_RTTVAR_SHIFT - 1);
+ tcp_set_new_cc(so, TCP_CC_ALGO_CUBIC_INDEX);
}
- tp->t_rtt = 0;
- tp->t_rxtshift = 0;
+}
- /*
- * the retransmit should happen at rtt + 4 * rttvar.
- * Because of the way we do the smoothing, srtt and rttvar
- * will each average +1/2 tick of bias. When we compute
- * the retransmit timer, we want 1/2 tick of rounding and
- * 1 extra tick because of +-1/2 tick uncertainty in the
- * firing of the timer. The bias will give us exactly the
- * 1.5 tick we need. But, because the bias is
- * statistical, we have to test that we don't drop below
- * the minimum feasible timer (which is 2 ticks).
- */
- TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp),
- max(tp->t_rttmin, rtt + 2), TCPTV_REXMTMAX);
+static void
+tcp_set_new_cc(struct socket *so, uint16_t cc_index)
+{
+ struct inpcb *inp = sotoinpcb(so);
+ struct tcpcb *tp = intotcpcb(inp);
+ u_char old_cc_index = 0;
+ if (tp->tcp_cc_index != cc_index) {
+ old_cc_index = tp->tcp_cc_index;
+
+ if (CC_ALGO(tp)->cleanup != NULL) {
+ CC_ALGO(tp)->cleanup(tp);
+ }
+ tp->tcp_cc_index = cc_index;
- /*
- * We received an ack for a packet that wasn't retransmitted;
- * it is probably safe to discard any error indications we've
- * received recently. This isn't quite right, but close enough
- * for now (a route might have failed after we sent a segment,
- * and the return path might not be symmetrical).
- */
- tp->t_softerror = 0;
+ tcp_cc_allocate_state(tp);
+
+ if (CC_ALGO(tp)->switch_to != NULL) {
+ CC_ALGO(tp)->switch_to(tp, old_cc_index);
+ }
+
+ tcp_ccdbg_trace(tp, NULL, TCP_CC_CHANGE_ALGO);
+ }
}
-/*
- * Determine a reasonable value for maxseg size.
- * If the route is known, check route for mtu.
- * If none, use an mss that can be handled on the outgoing
- * interface without forcing IP to fragment; if bigger than
- * an mbuf cluster (MCLBYTES), round down to nearest multiple of MCLBYTES
- * to utilize large mbufs. If no route is found, route has no mtu,
- * or the destination isn't local, use a default, hopefully conservative
- * size (usually 512 or the default IP max size, but no more than the mtu
- * of the interface), as we can't discover anything about intervening
- * gateways or networks. We also initialize the congestion/slow start
- * window to be a single segment if the destination isn't local.
- * While looking at the routing entry, we also initialize other path-dependent
- * parameters from pre-set or cached values in the routing entry.
- *
- * Also take into account the space needed for options that we
- * send regularly. Make maxseg shorter by that amount to assure
- * that we can send maxseg amount of data even when the options
- * are present. Store the upper limit of the length of options plus
- * data in maxopd.
- *
- * NOTE that this routine is only called when we process an incoming
- * segment, for outgoing segments only tcp_mssopt is called.
- *
- * In case of T/TCP, we call this routine during implicit connection
- * setup as well (offer = -1), to initialize maxseg from the cached
- * MSS of our peer.
- */
void
-tcp_mss(tp, offer, isipv6)
- struct tcpcb *tp;
- int offer;
-#if INET6
- int isipv6;
-#endif
+tcp_set_recv_bg(struct socket *so)
{
- register struct rtentry *rt;
- struct ifnet *ifp;
- register int rtt, mss;
- u_long bufsize;
- struct inpcb *inp;
- struct socket *so;
- struct rmxp_tao *taop;
- int origoffer = offer;
-#if INET6
- int lgminh = isipv6 ? sizeof (struct tcpip6hdr) :
- sizeof (struct tcpiphdr);
-#else /* INET6 */
-#define lgminh (sizeof (struct tcpiphdr))
-#endif /* INET6 */
+ if (!IS_TCP_RECV_BG(so)) {
+ so->so_flags1 |= SOF1_TRAFFIC_MGT_TCP_RECVBG;
+ }
- inp = tp->t_inpcb;
-#if INET6
- if (isipv6)
- rt = tcp_rtlookup6(inp);
- else
-#endif /* INET6 */
- rt = tcp_rtlookup(inp);
- if (rt == NULL) {
- tp->t_maxopd = tp->t_maxseg =
-#if INET6
- isipv6 ? tcp_v6mssdflt :
-#endif /* INET6 */
- tcp_mssdflt;
- return;
+ /* Unset Large Receive Offload on background sockets */
+ so_set_lro(so, SO_TC_BK);
+}
+
+void
+tcp_clear_recv_bg(struct socket *so)
+{
+ if (IS_TCP_RECV_BG(so)) {
+ so->so_flags1 &= ~(SOF1_TRAFFIC_MGT_TCP_RECVBG);
}
- ifp = rt->rt_ifp;
- so = inp->inp_socket;
- taop = rmx_taop(rt->rt_rmx);
- /*
- * Offer == -1 means that we didn't receive SYN yet,
- * use cached value in that case;
- */
- if (offer == -1)
- offer = taop->tao_mssopt;
/*
- * Offer == 0 means that there was no MSS on the SYN segment,
- * in this case we use tcp_mssdflt.
+ * Set/unset use of Large Receive Offload depending on
+ * the traffic class
*/
- if (offer == 0)
- offer =
-#if INET6
- isipv6 ? tcp_v6mssdflt :
-#endif /* INET6 */
- tcp_mssdflt;
- else
- /*
- * Sanity check: make sure that maxopd will be large
- * enough to allow some data on segments even is the
- * all the option space is used (40bytes). Otherwise
- * funny things may happen in tcp_output.
- */
- offer = max(offer, 64);
- taop->tao_mssopt = offer;
+ so_set_lro(so, so->so_traffic_class);
+}
+void
+inp_fc_unthrottle_tcp(struct inpcb *inp)
+{
+ struct tcpcb *tp = inp->inp_ppcb;
/*
- * While we're here, check if there's an initial rtt
- * or rttvar. Convert from the route-table units
- * to scaled multiples of the slow timeout timer.
+ * Back off the slow-start threshold and enter
+ * congestion avoidance phase
*/
- if (tp->t_srtt == 0 && (rtt = rt->rt_rmx.rmx_rtt)) {
- /*
- * XXX the lock bit for RTT indicates that the value
- * is also a minimum value; this is subject to time.
- */
- if (rt->rt_rmx.rmx_locks & RTV_RTT)
- tp->t_rttmin = rtt / (RTM_RTTUNIT / PR_SLOWHZ);
- tp->t_srtt = rtt / (RTM_RTTUNIT / (PR_SLOWHZ * TCP_RTT_SCALE));
- tcpstat.tcps_usedrtt++;
- if (rt->rt_rmx.rmx_rttvar) {
- tp->t_rttvar = rt->rt_rmx.rmx_rttvar /
- (RTM_RTTUNIT / (PR_SLOWHZ * TCP_RTTVAR_SCALE));
- tcpstat.tcps_usedrttvar++;
- } else {
- /* default variation is +- 1 rtt */
- tp->t_rttvar =
- tp->t_srtt * TCP_RTTVAR_SCALE / TCP_RTT_SCALE;
- }
- TCPT_RANGESET(tp->t_rxtcur,
- ((tp->t_srtt >> 2) + tp->t_rttvar) >> 1,
- tp->t_rttmin, TCPTV_REXMTMAX);
+ if (CC_ALGO(tp)->pre_fr != NULL) {
+ CC_ALGO(tp)->pre_fr(tp);
}
- /*
- * if there's an mtu associated with the route, use it
- * else, use the link mtu.
- */
- if (rt->rt_rmx.rmx_mtu)
- mss = rt->rt_rmx.rmx_mtu - lgminh;
- else
- mss =
-#if INET6
- isipv6 ? nd_ifinfo[rt->rt_ifp->if_index].linkmtu :
-#endif
- ifp->if_mtu - lgminh;
- if (rt->rt_rmx.rmx_mtu == 0) {
-#if INET6
- if (isipv6) {
- if (!in6_localaddr(&inp->in6p_faddr))
- mss = min(mss, tcp_v6mssdflt);
- } else
-#endif /* INET6 */
- if (!in_localaddr(inp->inp_faddr))
- mss = min(mss, tcp_mssdflt);
- }
- mss = min(mss, offer);
+ tp->snd_cwnd = tp->snd_ssthresh;
+ tp->t_flagsext &= ~TF_CWND_NONVALIDATED;
/*
- * maxopd stores the maximum length of data AND options
- * in a segment; maxseg is the amount of data in a normal
- * segment. We need to store this value (maxopd) apart
- * from maxseg, because now every segment carries options
- * and thus we normally have somewhat less data in segments.
+ * Restart counting for ABC as we changed the
+ * congestion window just now.
*/
- tp->t_maxopd = mss;
+ tp->t_bytes_acked = 0;
- /*
- * In case of T/TCP, origoffer==-1 indicates, that no segments
- * were received yet. In this case we just guess, otherwise
- * we do the same as before T/TCP.
+ /* Reset retransmit shift as we know that the reason
+ * for delay in sending a packet is due to flow
+ * control on the outgoing interface. There is no need
+ * to backoff retransmit timer.
*/
- if ((tp->t_flags & (TF_REQ_TSTMP|TF_NOOPT)) == TF_REQ_TSTMP &&
- (origoffer == -1 ||
- (tp->t_flags & TF_RCVD_TSTMP) == TF_RCVD_TSTMP))
- mss -= TCPOLEN_TSTAMP_APPA;
- if ((tp->t_flags & (TF_REQ_CC|TF_NOOPT)) == TF_REQ_CC &&
- (origoffer == -1 ||
- (tp->t_flags & TF_RCVD_CC) == TF_RCVD_CC))
- mss -= TCPOLEN_CC_APPA;
+ TCP_RESET_REXMT_STATE(tp);
-#if (MCLBYTES & (MCLBYTES - 1)) == 0
- if (mss > MCLBYTES)
- mss &= ~(MCLBYTES-1);
-#else
- if (mss > MCLBYTES)
- mss = mss / MCLBYTES * MCLBYTES;
-#endif
/*
- * If there's a pipesize, change the socket buffer
- * to that size. Make the socket buffers an integral
- * number of mss units; if the mss is larger than
- * the socket buffer, decrease the mss.
+ * Start the output stream again. Since we are
+ * not retransmitting data, do not reset the
+ * retransmit timer or rtt calculation.
*/
-#if RTV_SPIPE
- if ((bufsize = rt->rt_rmx.rmx_sendpipe) == 0)
-#endif
- bufsize = so->so_snd.sb_hiwat;
- if (bufsize < mss)
- mss = bufsize;
- else {
- bufsize = roundup(bufsize, mss);
- if (bufsize > sb_max)
- bufsize = sb_max;
- (void)sbreserve(&so->so_snd, bufsize);
- }
- tp->t_maxseg = mss;
+ tcp_output(tp);
+}
-#if RTV_RPIPE
- if ((bufsize = rt->rt_rmx.rmx_recvpipe) == 0)
-#endif
- bufsize = so->so_rcv.sb_hiwat;
- if (bufsize > mss) {
- bufsize = roundup(bufsize, mss);
- if (bufsize > sb_max)
- bufsize = sb_max;
- (void)sbreserve(&so->so_rcv, bufsize);
+static int
+tcp_getstat SYSCTL_HANDLER_ARGS
+{
+#pragma unused(oidp, arg1, arg2)
+
+ int error;
+ struct tcpstat *stat;
+ stat = &tcpstat;
+#if !CONFIG_EMBEDDED
+ struct tcpstat zero_stat;
+
+ if (tcp_disable_access_to_stats &&
+ !kauth_cred_issuser(kauth_cred_get())) {
+ bzero(&zero_stat, sizeof(zero_stat));
+ stat = &zero_stat;
}
- /*
- * Don't force slow-start on local network.
- */
-#if INET6
- if (isipv6) {
- if (!in6_localaddr(&inp->in6p_faddr))
- tp->snd_cwnd = mss;
- } else
-#endif /* INET6 */
- if (!in_localaddr(inp->inp_faddr))
- tp->snd_cwnd = mss;
- if (rt->rt_rmx.rmx_ssthresh) {
- /*
- * There's some sort of gateway or interface
- * buffer limit on the path. Use this to set
- * the slow start threshhold, but set the
- * threshold to no less than 2*mss.
- */
- tp->snd_ssthresh = max(2 * mss, rt->rt_rmx.rmx_ssthresh);
- tcpstat.tcps_usedssthresh++;
+#endif /* !CONFIG_EMBEDDED */
+
+ if (req->oldptr == 0) {
+ req->oldlen = (size_t)sizeof(struct tcpstat);
}
+
+ error = SYSCTL_OUT(req, stat, MIN(sizeof(tcpstat), req->oldlen));
+
+ return error;
}
/*
- * Determine the MSS option to send on an outgoing SYN.
+ * Checksum extended TCP header and data.
*/
int
-tcp_mssopt(tp, isipv6)
- struct tcpcb *tp;
-#if INET6
- int isipv6;
-#endif
+tcp_input_checksum(int af, struct mbuf *m, struct tcphdr *th, int off, int tlen)
{
- struct rtentry *rt;
- int mss;
-#if INET6
- int lgminh = isipv6 ? sizeof (struct tcpip6hdr) :
- sizeof (struct tcpiphdr);
-#else /* INET6 */
-#define lgminh (sizeof (struct tcpiphdr))
-#endif /* INET6 */
+ struct ifnet *ifp = m->m_pkthdr.rcvif;
+ switch (af) {
+ case AF_INET: {
+ struct ip *ip = mtod(m, struct ip *);
+ struct ipovly *ipov = (struct ipovly *)ip;
+
+ if (m->m_pkthdr.pkt_flags & PKTF_SW_LRO_DID_CSUM) {
+ return 0;
+ }
+
+ /* ip_stripoptions() must have been called before we get here */
+ ASSERT((ip->ip_hl << 2) == sizeof(*ip));
+
+ if ((hwcksum_rx || (ifp->if_flags & IFF_LOOPBACK) ||
+ (m->m_pkthdr.pkt_flags & PKTF_LOOP)) &&
+ (m->m_pkthdr.csum_flags & CSUM_DATA_VALID)) {
+ if (m->m_pkthdr.csum_flags & CSUM_PSEUDO_HDR) {
+ th->th_sum = m->m_pkthdr.csum_rx_val;
+ } else {
+ uint32_t sum = m->m_pkthdr.csum_rx_val;
+ uint32_t start = m->m_pkthdr.csum_rx_start;
+ int32_t trailer = (m_pktlen(m) - (off + tlen));
+
+ /*
+ * Perform 1's complement adjustment of octets
+ * that got included/excluded in the hardware-
+ * calculated checksum value. Ignore cases
+ * where the value already includes the entire
+ * IP header span, as the sum for those octets
+ * would already be 0 by the time we get here;
+ * IP has already performed its header checksum
+ * checks. If we do need to adjust, restore
+ * the original fields in the IP header when
+ * computing the adjustment value. Also take
+ * care of any trailing bytes and subtract out
+ * their partial sum.
+ */
+ ASSERT(trailer >= 0);
+ if ((m->m_pkthdr.csum_flags & CSUM_PARTIAL) &&
+ ((start != 0 && start != off) || trailer)) {
+ uint32_t swbytes = (uint32_t)trailer;
+
+ if (start < off) {
+ ip->ip_len += sizeof(*ip);
+#if BYTE_ORDER != BIG_ENDIAN
+ HTONS(ip->ip_len);
+ HTONS(ip->ip_off);
+#endif /* BYTE_ORDER != BIG_ENDIAN */
+ }
+ /* callee folds in sum */
+ sum = m_adj_sum16(m, start, off,
+ tlen, sum);
+ if (off > start) {
+ swbytes += (off - start);
+ } else {
+ swbytes += (start - off);
+ }
+
+ if (start < off) {
+#if BYTE_ORDER != BIG_ENDIAN
+ NTOHS(ip->ip_off);
+ NTOHS(ip->ip_len);
+#endif /* BYTE_ORDER != BIG_ENDIAN */
+ ip->ip_len -= sizeof(*ip);
+ }
+
+ if (swbytes != 0) {
+ tcp_in_cksum_stats(swbytes);
+ }
+ if (trailer != 0) {
+ m_adj(m, -trailer);
+ }
+ }
+
+ /* callee folds in sum */
+ th->th_sum = in_pseudo(ip->ip_src.s_addr,
+ ip->ip_dst.s_addr,
+ sum + htonl(tlen + IPPROTO_TCP));
+ }
+ th->th_sum ^= 0xffff;
+ } else {
+ uint16_t ip_sum;
+ int len;
+ char b[9];
+
+ bcopy(ipov->ih_x1, b, sizeof(ipov->ih_x1));
+ bzero(ipov->ih_x1, sizeof(ipov->ih_x1));
+ ip_sum = ipov->ih_len;
+ ipov->ih_len = (u_short)tlen;
+#if BYTE_ORDER != BIG_ENDIAN
+ HTONS(ipov->ih_len);
+#endif
+ len = sizeof(struct ip) + tlen;
+ th->th_sum = in_cksum(m, len);
+ bcopy(b, ipov->ih_x1, sizeof(ipov->ih_x1));
+ ipov->ih_len = ip_sum;
+
+ tcp_in_cksum_stats(len);
+ }
+ break;
+ }
#if INET6
- if (isipv6)
- rt = tcp_rtlookup6(tp->t_inpcb);
- else
-#endif /* INET6 */
- rt = tcp_rtlookup(tp->t_inpcb);
- if (rt == NULL)
- return
-#if INET6
- isipv6 ? tcp_v6mssdflt :
+ case AF_INET6: {
+ struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
+
+ if (m->m_pkthdr.pkt_flags & PKTF_SW_LRO_DID_CSUM) {
+ return 0;
+ }
+
+ if ((hwcksum_rx || (ifp->if_flags & IFF_LOOPBACK) ||
+ (m->m_pkthdr.pkt_flags & PKTF_LOOP)) &&
+ (m->m_pkthdr.csum_flags & CSUM_DATA_VALID)) {
+ if (m->m_pkthdr.csum_flags & CSUM_PSEUDO_HDR) {
+ th->th_sum = m->m_pkthdr.csum_rx_val;
+ } else {
+ uint32_t sum = m->m_pkthdr.csum_rx_val;
+ uint32_t start = m->m_pkthdr.csum_rx_start;
+ int32_t trailer = (m_pktlen(m) - (off + tlen));
+
+ /*
+ * Perform 1's complement adjustment of octets
+ * that got included/excluded in the hardware-
+ * calculated checksum value. Also take care
+ * of any trailing bytes and subtract out their
+ * partial sum.
+ */
+ ASSERT(trailer >= 0);
+ if ((m->m_pkthdr.csum_flags & CSUM_PARTIAL) &&
+ (start != off || trailer != 0)) {
+ uint16_t s = 0, d = 0;
+ uint32_t swbytes = (uint32_t)trailer;
+
+ if (IN6_IS_SCOPE_EMBED(&ip6->ip6_src)) {
+ s = ip6->ip6_src.s6_addr16[1];
+ ip6->ip6_src.s6_addr16[1] = 0;
+ }
+ if (IN6_IS_SCOPE_EMBED(&ip6->ip6_dst)) {
+ d = ip6->ip6_dst.s6_addr16[1];
+ ip6->ip6_dst.s6_addr16[1] = 0;
+ }
+
+ /* callee folds in sum */
+ sum = m_adj_sum16(m, start, off,
+ tlen, sum);
+ if (off > start) {
+ swbytes += (off - start);
+ } else {
+ swbytes += (start - off);
+ }
+
+ if (IN6_IS_SCOPE_EMBED(&ip6->ip6_src)) {
+ ip6->ip6_src.s6_addr16[1] = s;
+ }
+ if (IN6_IS_SCOPE_EMBED(&ip6->ip6_dst)) {
+ ip6->ip6_dst.s6_addr16[1] = d;
+ }
+
+ if (swbytes != 0) {
+ tcp_in6_cksum_stats(swbytes);
+ }
+ if (trailer != 0) {
+ m_adj(m, -trailer);
+ }
+ }
+
+ th->th_sum = in6_pseudo(
+ &ip6->ip6_src, &ip6->ip6_dst,
+ sum + htonl(tlen + IPPROTO_TCP));
+ }
+ th->th_sum ^= 0xffff;
+ } else {
+ tcp_in6_cksum_stats(tlen);
+ th->th_sum = in6_cksum(m, IPPROTO_TCP, off, tlen);
+ }
+ break;
+ }
#endif /* INET6 */
- tcp_mssdflt;
+ default:
+ VERIFY(0);
+ /* NOTREACHED */
+ }
+
+ if (th->th_sum != 0) {
+ tcpstat.tcps_rcvbadsum++;
+ IF_TCP_STATINC(ifp, badformat);
+ return -1;
+ }
+
+ return 0;
+}
+
+
+SYSCTL_PROC(_net_inet_tcp, TCPCTL_STATS, stats,
+ CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_LOCKED, 0, 0, tcp_getstat,
+ "S,tcpstat", "TCP statistics (struct tcpstat, netinet/tcp_var.h)");
+
+static int
+sysctl_rexmtthresh SYSCTL_HANDLER_ARGS
+{
+#pragma unused(arg1, arg2)
+
+ int error, val = tcprexmtthresh;
- mss = rt->rt_ifp->if_mtu - lgminh;
+ error = sysctl_handle_int(oidp, &val, 0, req);
+ if (error || !req->newptr) {
+ return error;
+ }
+
+ /*
+ * Constrain the number of duplicate ACKs
+ * to consider for TCP fast retransmit
+ * to either 2 or 3
+ */
- return mss;
+ if (val < 2 || val > 3) {
+ return EINVAL;
+ }
+
+ tcprexmtthresh = val;
+
+ return 0;
}
+
+SYSCTL_PROC(_net_inet_tcp, OID_AUTO, rexmt_thresh, CTLTYPE_INT | CTLFLAG_RW |
+ CTLFLAG_LOCKED, &tcprexmtthresh, 0, &sysctl_rexmtthresh, "I",
+ "Duplicate ACK Threshold for Fast Retransmit");
projects / apple / xnu.git / blobdiff