/*
- * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2011 Apple Inc. All rights reserved.
*
- * @APPLE_LICENSE_HEADER_START@
+ * @APPLE_OSREFERENCE_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 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.
*
- * This Original Code and all software distributed under the License are
- * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * 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.
+ * 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_LICENSE_HEADER_END@
+ * @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 <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 <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 <netinet/tcp_seq.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>
+#include <netinet/tcp_cc.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 */
#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>
#define DBG_LAYER_BEG NETDBG_CODE(DBG_NETTCP, 0)
#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;
+static int tcprexmtthresh = 2;
tcp_cc tcp_ccgen;
+#if IPSEC
+extern int ipsec_bypass;
+#endif
+
struct tcpstat tcpstat;
-SYSCTL_STRUCT(_net_inet_tcp, TCPCTL_STATS, stats,
- CTLFLAG_RD, &tcpstat , tcpstat, "");
-int log_in_vain = 0;
-SYSCTL_INT(_net_inet_tcp, OID_AUTO, log_in_vain, CTLFLAG_RW,
- &log_in_vain, 0, "");
+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");
+
+int tcp_delack_enabled = 3;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, delayed_ack, CTLFLAG_RW | CTLFLAG_LOCKED,
+ &tcp_delack_enabled, 0,
+ "Delay ACK to try and piggyback it onto a data packet");
+
+int tcp_lq_overflow = 1;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcp_lq_overflow, CTLFLAG_RW | CTLFLAG_LOCKED,
+ &tcp_lq_overflow, 0,
+ "Listen Queue Overflow");
+
+int tcp_recv_bg = 0;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, recvbg, CTLFLAG_RW | CTLFLAG_LOCKED,
+ &tcp_recv_bg, 0,
+ "Receive background");
+
+#if TCP_DROP_SYNFIN
+static int drop_synfin = 1;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, drop_synfin, CTLFLAG_RW | CTLFLAG_LOCKED,
+ &drop_synfin, 0, "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");
+
+__private_extern__ int tcp_reass_maxseg = 0;
+SYSCTL_INT(_net_inet_tcp_reass, OID_AUTO, maxsegments, CTLFLAG_RW | CTLFLAG_LOCKED,
+ &tcp_reass_maxseg, 0,
+ "Global maximum number of TCP Segments in Reassembly Queue");
+
+__private_extern__ int tcp_reass_qsize = 0;
+SYSCTL_INT(_net_inet_tcp_reass, OID_AUTO, cursegments, CTLFLAG_RD | CTLFLAG_LOCKED,
+ &tcp_reass_qsize, 0,
+ "Global number of TCP Segments currently in 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");
+
+
+__private_extern__ int slowlink_wsize = 8192;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, slowlink_wsize, CTLFLAG_RW | CTLFLAG_LOCKED,
+ &slowlink_wsize, 0, "Maximum advertised window size for slowlink");
+
+int maxseg_unacked = 8;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, maxseg_unacked, CTLFLAG_RW | CTLFLAG_LOCKED,
+ &maxseg_unacked, 0, "Maximum number of outstanding segments left unacked");
+
+int tcp_do_rfc3465 = 1;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, rfc3465, CTLFLAG_RW | CTLFLAG_LOCKED,
+ &tcp_do_rfc3465, 0, "");
+
+int tcp_do_rfc3465_lim2 = 1;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, rfc3465_lim2, CTLFLAG_RW | CTLFLAG_LOCKED,
+ &tcp_do_rfc3465_lim2, 0, "Appropriate bytes counting w/ L=2*SMSS");
-int tcp_delack_enabled = 1;
-SYSCTL_INT(_net_inet_tcp, OID_AUTO, delayed_ack, CTLFLAG_RW,
- &tcp_delack_enabled, 0, "");
+int rtt_samples_per_slot = 20;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, rtt_samples_per_slot, CTLFLAG_RW | CTLFLAG_LOCKED,
+ &rtt_samples_per_slot, 0, "Number of RTT samples stored for rtt history");
+
+int tcp_allowed_iaj = ALLOWED_IAJ;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, recv_allowed_iaj, CTLFLAG_RW | CTLFLAG_LOCKED,
+ &tcp_allowed_iaj, 0, "Allowed inter-packet arrival jiter");
+
+int tcp_acc_iaj_high_thresh = ACC_IAJ_HIGH_THRESH;
+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");
+
+#if CONFIG_IFEF_NOWINDOWSCALE
+int tcp_obey_ifef_nowindowscale = 0;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, obey_ifef_nowindowscale, CTLFLAG_RW | CTLFLAG_LOCKED,
+ &tcp_obey_ifef_nowindowscale, 0, "");
+#endif
+
+extern int tcp_TCPTV_MIN;
+extern int tcp_acc_iaj_high;
+extern int tcp_acc_iaj_react_limit;
+extern struct zone *tcp_reass_zone;
+
+
+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 */
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 *, unsigned int);
+static void tcp_pulloutofband(struct socket *,
+ struct tcphdr *, struct mbuf *, int);
+static int tcp_reass(struct tcpcb *, struct tcphdr *, int *,
+ struct mbuf *);
+static void tcp_xmit_timer(struct tcpcb *, int);
+static inline unsigned int tcp_maxmtu(struct rtentry *);
+static inline int tcp_stretch_ack_enable(struct tcpcb *tp);
+
+#if TRAFFIC_MGT
+static inline void update_iaj_state(struct tcpcb *tp, uint32_t tlen, int reset_size);
+void compute_iaj(struct tcpcb *tp);
+static inline void clear_iaj_state(struct tcpcb *tp);
+#endif /* TRAFFIC_MGT */
-/*
- * Neighbor Discovery, Neighbor Unreachability Detection
- * Upper layer hint.
- */
-#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); \
+#if INET6
+static inline unsigned int tcp_maxmtu6(struct rtentry *);
+#endif
+
+/* Neighbor Discovery, Neighbor Unreachability Detection Upper layer hint. */
+#if INET6
+#define ND6_HINT(tp) \
+do { \
+ if ((tp) && (tp)->t_inpcb && \
+ ((tp)->t_inpcb->inp_vflag & INP_IPV6) != 0 && \
+ (tp)->t_inpcb->in6p_route.ro_rt) \
+ nd6_nud_hint((tp)->t_inpcb->in6p_route.ro_rt, NULL, 0); \
+} while (0)
+#else
+#define ND6_HINT(tp)
+#endif
+
+extern void add_to_time_wait(struct tcpcb *, uint32_t delay);
+extern void postevent(struct socket *, struct sockbuf *, int);
+
+extern void ipfwsyslog( int level, const char *format,...);
+extern int ChkAddressOK( __uint32_t dstaddr, __uint32_t srcaddr );
+extern int fw_verbose;
+__private_extern__ int tcp_sockthreshold;
+__private_extern__ int tcp_win_scale;
+
+#if IPFIREWALL
+#define log_in_vain_log( a ) { \
+ if ( (log_in_vain == 3 ) && (fw_verbose == 2)) { /* Apple logging, log to ipfw.log */ \
+ ipfwsyslog a ; \
+ } \
+ else log a ; \
}
+#else
+#define log_in_vain_log( a ) { log a; }
+#endif
+int tcp_rcvunackwin = TCPTV_UNACKWIN;
+int tcp_maxrcvidle = TCPTV_MAXRCVIDLE;
+int tcp_rcvsspktcnt = TCP_RCV_SS_PKTCOUNT;
-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);
+uint32_t get_base_rtt(struct tcpcb *tp);
+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);
+#if TRAFFIC_MGT
+void
+reset_acc_iaj(struct tcpcb *tp)
+{
+ tp->acc_iaj = 0;
+ tp->iaj_rwintop = 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;
+ }
+}
-/*
- * 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).
- */
-#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; \
- } \
+static inline void
+clear_iaj_state(struct tcpcb *tp)
+{
+ tp->iaj_rcv_ts = 0;
}
-/*
- * Note:
- * in the ip header part of the ipqe_tcp structure only the length is used.
+/* 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.
*/
-int
-tcp_reass(tp, th, tilen, m, isipv6)
+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);
+}
+
+void
+compute_iaj(struct tcpcb *tp)
+{
+ /* 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)
+
+ uint32_t allowed_iaj, acc_iaj = 0;
+ uint32_t cur_iaj = tcp_now - tp->iaj_rcv_ts;
+
+ 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.
+ */
+ tp->avg_iaj = (((tp->avg_iaj << 4) - tp->avg_iaj) + cur_iaj) >> 4;
+
+ /* 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 << 4) - temp) + (cur_iaj_dev * cur_iaj_dev)) >> 4;
+
+ tp->std_dev_iaj = isqrt(mean);
+
+ DTRACE_TCP3(iaj, struct tcpcb *, tp, uint32_t, cur_iaj, uint32_t, allowed_iaj);
+
+ return;
+}
+#endif /* TRAFFIC_MGT */
+
+static int
+tcp_reass(tp, th, tlenp, m)
register struct tcpcb *tp;
register struct tcphdr *th;
- u_int16_t tilen;
+ int *tlenp;
struct mbuf *m;
-#if INET6
- int isipv6;
-#endif
{
- register struct ipqent *p, *q, *nq, *tiqe;
+ struct tseg_qent *q;
+ struct tseg_qent *p = NULL;
+ struct tseg_qent *nq;
+ struct tseg_qent *te = NULL;
struct socket *so = tp->t_inpcb->inp_socket;
int flags;
+ int dowakeup = 0;
/*
* 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 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.
+ */
+ if ((tp->t_flags & TF_STRETCHACK) != 0)
+ tcp_reset_stretch_ack(tp);
+
+ /* When the connection reaches a loss state, we need to send more acks
+ * for a period of time so that the sender's congestion window will
+ * open. Wait until we see some packets on the connection before
+ * stretching acks again.
+ */
+ tp->t_flagsext |= TF_RCVUNACK_WAITSS;
+ tp->rcv_waitforss = 0;
-#if 0 /* Not using GETTCP(m) macro */
- m->m_pkthdr.header = ti;
-#endif
+
+#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) {
+ if (th->th_seq != tp->rcv_nxt &&
+ tcp_reass_qsize + 1 >= tcp_reass_maxseg) {
+ 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_noblock(tcp_reass_zone);
+ if (te == NULL) {
+ tcpstat.tcps_rcvmemdrop++;
+ m_freem(m);
+ return (0);
+ }
+ tcp_reass_qsize++;
+
/*
* 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;
-
/* 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 (i >= *tlenp) {
tcpstat.tcps_rcvduppack++;
- tcpstat.tcps_rcvdupbyte += tilen;
+ tcpstat.tcps_rcvdupbyte += *tlenp;
+ if (nstat_collect) {
+ nstat_route_rx(tp->t_inpcb->inp_route.ro_rt, 1, *tlenp, NSTAT_RX_FLAG_DUPLICATE);
+ locked_add_64(&tp->t_inpcb->inp_stat->rxpackets, 1);
+ locked_add_64(&tp->t_inpcb->inp_stat->rxbytes, *tlenp);
+ tp->t_stat.rxduplicatebytes += *tlenp;
+ }
m_freem(m);
- FREE(tiqe, M_SONAME);
-
-#if 1 /* XXX: NetBSD just return 0 here */
+ zfree(tcp_reass_zone, te);
+ tcp_reass_qsize--;
/*
* Try to present any queued data
* at the left window edge to the user.
* completes.
*/
goto present; /* ??? */
-#endif
}
m_adj(m, i);
- tilen -= i;
+ *tlenp -= i;
th->th_seq += i;
}
}
tcpstat.tcps_rcvoopack++;
- tcpstat.tcps_rcvoobyte += tilen;
+ tcpstat.tcps_rcvoobyte += *tlenp;
+ if (nstat_collect) {
+ nstat_route_rx(tp->t_inpcb->inp_route.ro_rt, 1, *tlenp, NSTAT_RX_FLAG_OUT_OF_ORDER);
+ locked_add_64(&tp->t_inpcb->inp_stat->rxpackets, 1);
+ locked_add_64(&tp->t_inpcb->inp_stat->rxbytes, *tlenp);
+ tp->t_stat.rxoutoforderbytes += *tlenp;
+ }
/*
* 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;
-
+ register 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);
+ 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);
+ tcp_reass_qsize--;
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);
}
present:
*/
if (!TCPS_HAVEESTABLISHED(tp->t_state))
return (0);
- q = tp->segq.lh_first;
- if (!q || q->ipqe_tcp->ti_seq != tp->rcv_nxt)
+ q = LIST_FIRST(&tp->t_segq);
+ if (!q || q->tqe_th->th_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
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);
+ tp->rcv_nxt += q->tqe_len;
+ flags = q->tqe_th->th_flags & TH_FIN;
+ nq = LIST_NEXT(q, tqe_q);
+ LIST_REMOVE(q, tqe_q);
if (so->so_state & SS_CANTRCVMORE)
- m_freem(q->ipqe_m);
- else
- sbappend(&so->so_rcv, q->ipqe_m);
- FREE(q, M_SONAME);
+ m_freem(q->tqe_m);
+ else {
+ so_recv_data_stat(so, q->tqe_m, 0); /* XXXX */
+ if (sbappendstream(&so->so_rcv, q->tqe_m))
+ dowakeup = 1;
+ }
+ zfree(tcp_reass_zone, q);
+ tcp_reass_qsize--;
q = nq;
- } while (q && q->ipqe_tcp->ti_seq == tp->rcv_nxt);
+ } while (q && q->tqe_th->th_seq == tp->rcv_nxt);
+ ND6_HINT(tp);
+
#if INET6
- if (isipv6)
- ND6_HINT(tp);
+ if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) {
+
+ KERNEL_DEBUG(DBG_LAYER_BEG,
+ ((tp->t_inpcb->inp_fport << 16) | tp->t_inpcb->inp_lport),
+ (((tp->t_inpcb->in6p_laddr.s6_addr16[0] & 0xffff) << 16) |
+ (tp->t_inpcb->in6p_faddr.s6_addr16[0] & 0xffff)),
+ 0,0,0);
+ }
+ else
#endif
+ {
+ KERNEL_DEBUG(DBG_LAYER_BEG,
+ ((tp->t_inpcb->inp_fport << 16) | tp->t_inpcb->inp_lport),
+ (((tp->t_inpcb->inp_laddr.s_addr & 0xffff) << 16) |
+ (tp->t_inpcb->inp_faddr.s_addr & 0xffff)),
+ 0,0,0);
+ }
+ if (dowakeup)
+ sorwakeup(so); /* done with socket lock held */
+ return (flags);
- 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);
+}
- sorwakeup(so);
- return (flags);
+/*
+ * Reduce congestion window.
+ */
+static void
+tcp_reduce_congestion_window(
+ struct tcpcb *tp, struct tcphdr *th)
+{
+ /*
+ * 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, th);
+ ENTER_FASTRECOVERY(tp);
+ tp->snd_recover = tp->snd_max;
+ tp->t_timer[TCPT_REXMT] = 0;
+ tp->t_rtttime = 0;
+ tp->ecn_flags |= TE_SENDCWR;
+ tp->snd_cwnd = tp->snd_ssthresh +
+ tp->t_maxseg * tcprexmtthresh;
}
+
/*
* TCP input routine, follows pages 65-76 of the
* protocol specification dated September, 1981 very closely.
*/
#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);
- return IPPROTO_DONE;
+#pragma unused(proto)
+ register struct mbuf *m = *mp;
+ struct in6_ifaddr *ia6;
+
+ IP6_EXTHDR_CHECK(m, *offp, sizeof(struct tcphdr), return IPPROTO_DONE);
+
+ /*
+ * draft-itojun-ipv6-tcp-to-anycast
+ * better place to put this in?
+ */
+ ia6 = ip6_getdstifaddr(m);
+ if (ia6 != NULL) {
+ IFA_LOCK_SPIN(&ia6->ia_ifa);
+ if (ia6->ia6_flags & IN6_IFF_ANYCAST) {
+ struct ip6_hdr *ip6;
+
+ IFA_UNLOCK(&ia6->ia_ifa);
+ IFA_REMREF(&ia6->ia_ifa);
+ ip6 = mtod(m, struct ip6_hdr *);
+ icmp6_error(m, ICMP6_DST_UNREACH,
+ ICMP6_DST_UNREACH_ADDR,
+ (caddr_t)&ip6->ip6_dst - (caddr_t)ip6);
+ return (IPPROTO_DONE);
+ }
+ IFA_UNLOCK(&ia6->ia_ifa);
+ IFA_REMREF(&ia6->ia_ifa);
+ }
+
+ tcp_input(m, *offp);
+ return (IPPROTO_DONE);
}
#endif
+/* 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) {
+ if (tp->rcv_by_unackwin >= (maxseg_unacked * tp->t_maxseg) &&
+ TSTMP_GT(tp->rcv_unackwin + tcp_maxrcvidle, tcp_now) &&
+ (((tp->t_flagsext & TF_RCVUNACK_WAITSS) == 0) ||
+ (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);
+ tp->rcv_by_unackwin = 0;
+ tp->rcv_unackwin = tcp_now + tcp_rcvunackwin;
+}
+
void
-tcp_input(m, off)
+tcp_input(m, off0)
struct mbuf *m;
- int off;
+ int off0;
{
register struct tcphdr *th;
register struct ip *ip = NULL;
register struct inpcb *inp;
u_char *optp = NULL;
int optlen = 0;
- int len, toff;
- int hdroptlen;
- u_int16_t tilen;
+ int len, tlen, off;
+ int drop_hdrlen;
register struct tcpcb *tp = 0;
register int thflags;
struct socket *so = 0;
int todrop, acked, ourfinisacked, needoutput = 0;
struct in_addr laddr;
-#if 0
+#if INET6
struct in6_addr laddr6;
#endif
int dropsocket = 0;
int iss = 0;
- u_long tiwin;
+ int nosock = 0;
+ u_int32_t 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;
+ struct sockaddr_in *next_hop = NULL;
#if TCPDEBUG
short ostate = 0;
#endif
+ struct m_tag *fwd_tag;
+ u_char ip_ecn = IPTOS_ECN_NOTECT;
+ unsigned int ifscope, nocell = 0;
+ uint8_t isconnected, isdisconnected;
+
+ /*
+ * 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_flags & M_PKTHDR) && m->m_pkthdr.rcvif != NULL)
+ ifscope = m->m_pkthdr.rcvif->if_index;
+ else
+ ifscope = IFSCOPE_NONE;
+
+ /* Since this is an entry point for input processing of tcp packets, we
+ * can update the tcp clock here.
+ */
+ calculate_tcp_clock();
+
+ /* 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);
+ }
+
#if INET6
struct ip6_hdr *ip6 = NULL;
- int lgminh;
-#else /* INET6 */
-#define lgminh (sizeof (struct tcpiphdr))
+ int isipv6;
#endif /* INET6 */
- int isipv6 = (mtod(m, struct ip *)->ip_v == 6) ? 1 : 0;
-
+ int rstreason; /* For badport_bandlim accounting purposes */
struct proc *proc0=current_proc();
-
+
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));
tcpstat.tcps_rcvtotal++;
- /*
- * Get IP and TCP header together in first mbuf.
- * Note: IP leaves IP header in first mbuf.
- */
- th = mtod(m, struct tcpiphdr *);
- 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);
-#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
- }
-#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;
- }
-#endif /* INET6 */
#if INET6
if (isipv6) {
- IP6_EXTHDR_CHECK(m, off, sizeof(struct tcphdr), );
+ /* IP6_EXTHDR_CHECK() is already done at tcp6_input() */
ip6 = mtod(m, struct ip6_hdr *);
- tilen = ntohs(ip6->ip6_plen) - off + sizeof(*ip6);
+ tlen = sizeof(*ip6) + ntohs(ip6->ip6_plen) - off0;
+ th = (struct tcphdr *)((caddr_t)ip6 + off0);
- if (in6_cksum(m, IPPROTO_TCP, off, tilen)) {
- tcpstat.tcps_rcvbadsum++;
- goto drop;
+ if ((apple_hwcksum_rx != 0) && (m->m_pkthdr.csum_flags & CSUM_DATA_VALID)) {
+ if (m->m_pkthdr.csum_flags & CSUM_PSEUDO_HDR)
+ th->th_sum = m->m_pkthdr.csum_data;
+ else
+ th->th_sum = in6_cksum_phdr(&ip6->ip6_src,
+ &ip6->ip6_dst, htonl(sizeof(struct tcphdr)),
+ htonl(IPPROTO_TCP));
+
+ th->th_sum ^= 0xffff;
+ if (th->th_sum) {
+ tcpstat.tcps_rcvbadsum++;
+ goto dropnosock;
+ }
+ }
+ else {
+ if (in6_cksum(m, IPPROTO_TCP, off0, tlen)) {
+ tcpstat.tcps_rcvbadsum++;
+ goto dropnosock;
+ }
}
- th = (struct tcphdr *)((caddr_t)ip6 + off);
+
+ 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);
+ /*
+ * 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.
+ */
+ if (IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src)) {
+ /* XXX stat */
+ goto dropnosock;
+ }
+ DTRACE_TCP5(receive, sruct 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 */
{
- /*
- * Get IP and TCP header together in first mbuf.
- * Note: IP leaves IP header in first mbuf.
- */
- /* XXX: should we still require this for IPv4? */
- if (off > sizeof (struct ip)) {
- ip_stripoptions(m, (struct mbuf *)0);
- off = sizeof(struct ip);
- }
- if (m->m_len < lgminh) {
- if ((m = m_pullup(m, lgminh)) == 0) {
- tcpstat.tcps_rcvshort++;
- return;
- }
+ /*
+ * 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, (struct mbuf *)0);
+ off0 = sizeof(struct ip);
+ if (m->m_pkthdr.csum_flags & CSUM_TCP_SUM16)
+ m->m_pkthdr.csum_flags = 0; /* invalidate hwcksuming */
+
+ }
+ if (m->m_len < sizeof (struct tcpiphdr)) {
+ if ((m = m_pullup(m, sizeof (struct tcpiphdr))) == 0) {
+ tcpstat.tcps_rcvshort++;
+ return;
}
- ip = mtod(m, struct ip *);
- ipov = (struct ipovly *)ip;
+ }
+ ip = mtod(m, struct ip *);
+ ipov = (struct ipovly *)ip;
+ th = (struct tcphdr *)((caddr_t)ip + off0);
+ tlen = ip->ip_len;
+
+ 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);
+
+ if (m->m_pkthdr.csum_flags & CSUM_DATA_VALID) {
+ if (m->m_pkthdr.csum_flags & CSUM_TCP_SUM16) {
+ u_short pseudo;
+ char b[9];
+ *(uint32_t*)&b[0] = *(uint32_t*)&ipov->ih_x1[0];
+ *(uint32_t*)&b[4] = *(uint32_t*)&ipov->ih_x1[4];
+ *(uint8_t*)&b[8] = *(uint8_t*)&ipov->ih_x1[8];
+
+ bzero(ipov->ih_x1, sizeof(ipov->ih_x1));
+ ipov->ih_len = (u_short)tlen;
+
+#if BYTE_ORDER != BIG_ENDIAN
+ HTONS(ipov->ih_len);
+#endif
+ pseudo = in_cksum(m, sizeof (struct ip));
+
+ *(uint32_t*)&ipov->ih_x1[0] = *(uint32_t*)&b[0];
+ *(uint32_t*)&ipov->ih_x1[4] = *(uint32_t*)&b[4];
+ *(uint8_t*)&ipov->ih_x1[8] = *(uint8_t*)&b[8];
+
+ th->th_sum = in_addword(pseudo, (m->m_pkthdr.csum_data & 0xFFFF));
+ } else {
+ if (m->m_pkthdr.csum_flags & CSUM_PSEUDO_HDR)
+ th->th_sum = m->m_pkthdr.csum_data;
+ else
+ th->th_sum = in_pseudo(ip->ip_src.s_addr,
+ ip->ip_dst.s_addr, htonl(m->m_pkthdr.csum_data +
+ ip->ip_len + IPPROTO_TCP));
+ }
+ th->th_sum ^= 0xffff;
+ } else {
+ char b[9];
/*
* Checksum extended TCP header and data.
*/
- tilen = ip->ip_len;
- len = sizeof (struct ip) + tilen;
+ *(uint32_t*)&b[0] = *(uint32_t*)&ipov->ih_x1[0];
+ *(uint32_t*)&b[4] = *(uint32_t*)&ipov->ih_x1[4];
+ *(uint8_t*)&b[8] = *(uint8_t*)&ipov->ih_x1[8];
+
+ len = sizeof (struct ip) + tlen;
bzero(ipov->ih_x1, sizeof(ipov->ih_x1));
- ipov->ih_len = (u_short)tilen;
+ ipov->ih_len = (u_short)tlen;
+
+#if BYTE_ORDER != BIG_ENDIAN
HTONS(ipov->ih_len);
- th = (struct tcphdr *)((caddr_t)ip + off);
+#endif
+
th->th_sum = in_cksum(m, len);
- if (th->th_sum) {
- tcpstat.tcps_rcvbadsum++;
- goto drop;
- }
+
+ *(uint32_t*)&ipov->ih_x1[0] = *(uint32_t*)&b[0];
+ *(uint32_t*)&ipov->ih_x1[4] = *(uint32_t*)&b[4];
+ *(uint8_t*)&ipov->ih_x1[8] = *(uint8_t*)&b[8];
+
+ tcp_in_cksum_stats(len);
+ }
+ if (th->th_sum) {
+ tcpstat.tcps_rcvbadsum++;
+ goto dropnosock;
+ }
+#if INET6
+ /* Re-initialization for later version check */
+ ip->ip_v = IPVERSION;
+#endif
+ ip_ecn = (ip->ip_tos & IPTOS_ECN_MASK);
}
/*
* Check that TCP offset makes sense,
* pull out TCP options and adjust length. XXX
*/
- toff = th->th_off << 2;
- if (toff < sizeof (struct tcphdr) || toff > tilen) {
+ off = th->th_off << 2;
+ if (off < sizeof (struct tcphdr) || off > tlen) {
tcpstat.tcps_rcvbadoff++;
- goto drop;
+ goto dropnosock;
}
- tilen -= toff;
- if (toff > sizeof (struct tcphdr)) {
+ tlen -= off; /* tlen is used instead of ti->ti_len */
+ if (off > sizeof (struct tcphdr)) {
#if INET6
if (isipv6) {
- IP6_EXTHDR_CHECK(m, off, toff, );
+ IP6_EXTHDR_CHECK(m, off0, off, return);
ip6 = mtod(m, struct ip6_hdr *);
- th = (struct tcphdr *)((caddr_t)ip6 + off);
+ th = (struct tcphdr *)((caddr_t)ip6 + off0);
} else
#endif /* INET6 */
{
- if (m->m_len < sizeof(struct ip) + toff) {
- if ((m = m_pullup(m, sizeof (struct ip) + toff)) == 0) {
+ 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 *);
ipov = (struct ipovly *)ip;
- th = (struct tcphdr *)((caddr_t)ip + off);
+ th = (struct tcphdr *)((caddr_t)ip + off0);
}
}
- optlen = toff - sizeof (struct tcphdr);
+ optlen = off - sizeof (struct tcphdr);
optp = (u_char *)(th + 1);
/*
* Do quick retrieval of timestamp options ("options
* tcp_dooptions(), etc.
*/
if ((optlen == TCPOLEN_TSTAMP_APPA ||
- (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;
+ *(u_int32_t *)optp == htonl(TCPOPT_TSTAMP_HDR) &&
+ (th->th_flags & TH_SYN) == 0) {
+ to.to_flags |= 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 */
}
thflags = th->th_flags;
+#if TCP_DROP_SYNFIN
+ /*
+ * 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.
+ */
+ if (drop_synfin && (thflags & (TH_SYN|TH_FIN)) == (TH_SYN|TH_FIN))
+ goto dropnosock;
+#endif
+
/*
* 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
/*
- * Drop TCP, IP headers and TCP options.
+ * 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.
*/
- hdroptlen = off+toff;
- m->m_data += hdroptlen;
- m->m_len -= hdroptlen;
+ drop_hdrlen = off0 + off;
/*
* Locate pcb for segment.
*/
findpcb:
+
+ isconnected = FALSE;
+ isdisconnected = FALSE;
+
#if IPFIREWALL_FORWARD
- if (ip_fw_fwd_addr != NULL
+ if (next_hop != NULL
#if INET6
- && isipv6 == NULL
+ && isipv6 == 0 /* IPv6 support is not yet */
#endif /* INET6 */
) {
/*
/*
* No, then it's new. Try find the ambushing socket
*/
- if (!ip_fw_fwd_addr->sin_port) {
+ if (!next_hop->sin_port) {
inp = in_pcblookup_hash(&tcbinfo, ip->ip_src,
- th->th_sport, ip_fw_fwd_addr->sin_addr,
+ th->th_sport, next_hop->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,
+ next_hop->sin_addr,
+ ntohs(next_hop->sin_port), 1,
m->m_pkthdr.rcvif);
}
}
- ip_fw_fwd_addr = NULL;
} else
#endif /* IPFIREWALL_FORWARD */
-
+ {
#if INET6
if (isipv6)
inp = in6_pcblookup_hash(&tcbinfo, &ip6->ip6_src, th->th_sport,
#endif /* INET6 */
inp = in_pcblookup_hash(&tcbinfo, ip->ip_src, th->th_sport,
ip->ip_dst, th->th_dport, 1, m->m_pkthdr.rcvif);
+ }
+
+ /*
+ * 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.
+ */
+ if (inp != NULL && (inp->inp_flags & INP_BOUND_IF))
+ ifscope = inp->inp_boundif;
+ /*
+ * If the PCB is present and the socket isn't allowed to use
+ * the cellular interface, indicate it as such for tcp_respond.
+ */
+ if (inp != NULL && (inp->inp_flags & INP_NO_IFT_CELLULAR))
+ nocell = 1;
#if IPSEC
- /* due to difference from other BSD stacks */
- m->m_data -= hdroptlen;
- m->m_len += hdroptlen;
+ if (ipsec_bypass == 0) {
#if INET6
- if (isipv6) {
- if (inp != NULL && ipsec6_in_reject_so(m, inp->inp_socket)) {
- ipsec6stat.in_polvio++;
- goto drop;
- }
- } else
+ if (isipv6) {
+ if (inp != NULL && ipsec6_in_reject_so(m, inp->inp_socket)) {
+ IPSEC_STAT_INCREMENT(ipsec6stat.in_polvio);
+ if (in_pcb_checkstate(inp, WNT_RELEASE, 0) == WNT_STOPUSING)
+ inp = NULL; // pretend we didn't find it
+ goto dropnosock;
+ }
+ } else
#endif /* INET6 */
- if (inp != NULL && ipsec4_in_reject_so(m, inp->inp_socket)) {
- ipsecstat.in_polvio++;
- goto drop;
+ if (inp != NULL && ipsec4_in_reject_so(m, inp->inp_socket)) {
+ IPSEC_STAT_INCREMENT(ipsecstat.in_polvio);
+ if (in_pcb_checkstate(inp, WNT_RELEASE, 0) == WNT_STOPUSING)
+ inp = NULL; // pretend we didn't find it
+ goto dropnosock;
+ }
}
- m->m_data += hdroptlen;
- m->m_len -= hdroptlen;
#endif /*IPSEC*/
/*
* but should either do a listen or a connect soon.
*/
if (inp == NULL) {
- if (log_in_vain && thflags & TH_SYN) {
+ if (log_in_vain) {
#if INET6
- char buf[INET6_ADDRSTRLEN];
+ char dbuf[MAX_IPv6_STR_LEN], sbuf[MAX_IPv6_STR_LEN];
#else /* INET6 */
- char buf[4*sizeof "123"];
+ char dbuf[MAX_IPv4_STR_LEN], sbuf[MAX_IPv4_STR_LEN];
#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 {
+ inet_ntop(AF_INET6, &ip6->ip6_dst, dbuf, sizeof(dbuf));
+ inet_ntop(AF_INET6, &ip6->ip6_src, sbuf, sizeof(sbuf));
+ } 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));
+ {
+ 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 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 3:
+ if ((thflags & TH_SYN) &&
+ !(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;
}
-#endif /* INET6 */
}
-#if ICMP_BANDLIM
- if (badport_bandlim(1) < 0)
- 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)
+ goto dropnosock;
+ break;
+ case 2:
+ goto dropnosock;
+ default:
+ goto dropnosock;
+ }
+ }
+ rstreason = BANDLIM_RST_CLOSEDPORT;
+ 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
- goto dropwithreset;
+ goto dropnosock;
+ }
+
+ tcp_lock(so, 1, 0);
+ if (in_pcb_checkstate(inp, WNT_RELEASE, 1) == WNT_STOPUSING) {
+ tcp_unlock(so, 1, (void *)2);
+ inp = NULL; // pretend we didn't find it
+ goto dropnosock;
}
+
tp = intotcpcb(inp);
- if (tp == 0)
+ if (tp == 0) {
+ rstreason = BANDLIM_RST_CLOSEDPORT;
goto dropwithreset;
+ }
if (tp->t_state == TCPS_CLOSED)
goto drop;
else
tiwin = th->th_win;
- so = inp->inp_socket;
+#if CONFIG_MACF_NET
+ if (mac_inpcb_check_deliver(inp, m, AF_INET, SOCK_STREAM))
+ goto drop;
+#endif
+
+ /* Radar 7377561: Avoid processing packets while closing a listen socket */
+ if (tp->t_state == TCPS_LISTEN && (so->so_options & SO_ACCEPTCONN) == 0)
+ 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)
- tcp_saveip._tcp_si6 = *ip6;
+ bcopy((char *)ip6, (char *)tcp_saveipgen,
+ sizeof(*ip6));
else
- tcp_saveip._tcp_si4 = *ip;
-#else /* INET6 */
- tcp_saveip = *ip;
#endif /* INET6 */
-
+ bcopy((char *)ip, (char *)tcp_saveipgen, sizeof(*ip));
tcp_savetcp = *th;
}
#endif
if (so->so_options & SO_ACCEPTCONN) {
- register struct tcpcb *tp0 = tp;
+ register struct tcpcb *tp0 = tp;
struct socket *so2;
-#if IPSEC
struct socket *oso;
-#endif
+ struct sockaddr_storage from;
#if INET6
struct inpcb *oinp = sotoinpcb(so);
#endif /* INET6 */
+ unsigned int head_ifscope;
+ unsigned int head_nocell;
+
+ /* Get listener's bound-to-interface, if any */
+ head_ifscope = (inp->inp_flags & INP_BOUND_IF) ?
+ inp->inp_boundif : IFSCOPE_NONE;
+ /* Get listener's no-cellular information, if any */
+ head_nocell = (inp->inp_flags & INP_NO_IFT_CELLULAR) ? 1 : 0;
-#if !IPSEC
+ /*
+ * 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_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_RST) {
+ goto drop;
+ }
if (thflags & TH_ACK) {
+ tp = NULL;
tcpstat.tcps_badsyn++;
+ rstreason = BANDLIM_RST_OPENPORT;
goto dropwithreset;
}
+
+ /* We come here if there is no SYN set */
+ tcpstat.tcps_badsyn++;
goto drop;
}
-#endif
KERNEL_DEBUG(DBG_FNC_TCP_NEWCONN | DBG_FUNC_START,0,0,0,0,0);
- so2 = sonewconn(so, 0);
+ 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;
+ }
+ /*
+ * 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 (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
+ 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;
+#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. RFC2462 does not suggest dropping
+ * SYN in this case.
+ * If we decipher RFC2462 5.5.4, it says like this:
+ * 1. use of deprecated addr with existing
+ * communication is okay - "SHOULD continue to be
+ * used"
+ * 2. use of it with new communication:
+ * (2a) "SHOULD NOT be used if alternate address
+ * with sufficient scope is available"
+ * (2b) nothing mentioned otherwise.
+ * Here we fall into (2b) case as we have no choice in
+ * our source address selection - we must obey the peer.
+ *
+ * The wording in RFC2462 is confusing, and there are
+ * multiple description text for deprecated address
+ * handling - worse, they are not exactly the same.
+ * I believe 5.5.4 is the best one, so we follow 5.5.4.
+ */
+ if (isipv6 && !ip6_use_deprecated) {
+ struct in6_ifaddr *ia6;
+
+ ia6 = ip6_getdstifaddr(m);
+ if (ia6 != NULL) {
+ IFA_LOCK_SPIN(&ia6->ia_ifa);
+ if (ia6->ia6_flags & IN6_IFF_DEPRECATED) {
+ IFA_UNLOCK(&ia6->ia_ifa);
+ IFA_REMREF(&ia6->ia_ifa);
+ tp = NULL;
+ rstreason = BANDLIM_RST_OPENPORT;
+ goto dropwithreset;
+ }
+ IFA_UNLOCK(&ia6->ia_ifa);
+ IFA_REMREF(&ia6->ia_ifa);
+ }
+ }
+#endif
+ if (so->so_filt) {
+#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;
+ }
+ 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;
+ }
+ so2 = sonewconn(so, 0, (struct sockaddr*)&from);
+ } else {
+ so2 = sonewconn(so, 0, NULL);
+ }
if (so2 == 0) {
tcpstat.tcps_listendrop++;
- so2 = sodropablereq(so);
- if (so2) {
- tcp_drop(sototcpcb(so2), ETIMEDOUT);
- so2 = sonewconn(so, 0);
+ if (tcp_dropdropablreq(so)) {
+ if (so->so_filt)
+ so2 = sonewconn(so, 0, (struct sockaddr*)&from);
+ else
+ so2 = sonewconn(so, 0, NULL);
}
- if (!so2)
+ if (!so2)
goto drop;
}
-#if IPSEC
+
+ /* Point "inp" and "tp" in tandem to new socket */
+ inp = (struct inpcb *)so2->so_pcb;
+ tp = intotcpcb(inp);
+
oso = so;
-#endif
+ tcp_unlock(so, 0, 0); /* Unlock but keep a reference on listener for now */
+
so = so2;
+ tcp_lock(so, 1, 0);
/*
- * This is ugly, but ....
- *
* Mark socket as temporary until we're
* committed to keeping it. The code at
* ``drop'' and ``dropwithreset'' check the
* 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++;
- inp = (struct inpcb *)so->so_pcb;
+ /*
+ * Inherit INP_BOUND_IF from listener; testing if
+ * head_ifscope is non-zero 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 != IFSCOPE_NONE) {
+ inp->inp_flags |= INP_BOUND_IF;
+ inp->inp_boundif = head_ifscope;
+ }
+ /*
+ * Inherit INP_NO_IFT_CELLULAR from listener.
+ */
+ if (head_nocell) {
+ inp->inp_flags |= INP_NO_IFT_CELLULAR;
+ }
#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;
- }
+ inp->inp_vflag &= ~INP_IPV6;
+ inp->inp_vflag |= INP_IPV4;
#endif /* INET6 */
- inp->inp_laddr = ip->ip_dst;
+ inp->inp_laddr = ip->ip_dst;
#if INET6
}
#endif /* INET6 */
-
inp->inp_lport = th->th_dport;
- if (in_pcbinshash(inp) != 0) {
+ if (in_pcbinshash(inp, 0) != 0) {
/*
- * Undo the assignments above if we failed to put
- * the PCB on the hash lists.
+ * Undo the assignments above if we failed to
+ * put the PCB on the hash lists.
*/
#if INET6
if (isipv6)
#endif /* INET6 */
inp->inp_laddr.s_addr = INADDR_ANY;
inp->inp_lport = 0;
+ tcp_lock(oso, 0, 0); /* release ref on parent */
+ tcp_unlock(oso, 1, 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;
- }
- 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
+ /*
+ * 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.
- */
+ * 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);
+ if (oinp->in6p_outputopts)
+ inp->in6p_outputopts =
+ ip6_copypktopts(oinp->in6p_outputopts,
+ M_NOWAIT);
} else
#endif /* INET6 */
inp->inp_options = ip_srcroute();
+ tcp_lock(oso, 0, 0);
#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");
+ 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
-
- tp = intotcpcb(inp);
+ /* 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);
+ tp->t_flags |= tp0->t_flags & (TF_NOPUSH|TF_NOOPT|TF_NODELAY);
+ tp->t_flagsext |= (tp0->t_flagsext & TF_RXTFINDROP);
+ tp->t_keepinit = tp0->t_keepinit;
+ tp->t_inpcb->inp_ip_ttl = tp0->t_inpcb->inp_ip_ttl;
+
+ /* now drop the reference on the listener */
+ tcp_unlock(oso, 1, 0);
/* 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 (inp->inp_pcbinfo->ipi_count < tcp_sockthreshold) {
+ tp->request_r_scale = max(tcp_win_scale, tp->request_r_scale);
+ so->so_rcv.sb_hiwat = imin(TCP_MAXWIN << tp->request_r_scale, (sb_max / (MSIZE+MCLBYTES)) * MCLBYTES);
+ }
+ else {
+ while (tp->request_r_scale < TCP_MAX_WINSHIFT &&
+ TCP_MAXWIN << tp->request_r_scale <
+ so->so_rcv.sb_hiwat)
+ tp->request_r_scale++;
+ }
KERNEL_DEBUG(DBG_FNC_TCP_NEWCONN | DBG_FUNC_END,0,0,0,0,0);
}
}
+ lck_mtx_assert(&((struct inpcb *)so->so_pcb)->inpcb_mtx, LCK_MTX_ASSERT_OWNED);
-#if INET6
- /* save packet options if user wanted */
- if (isipv6 && (inp->in6p_flags & INP_CONTROLOPTS) != 0) {
- struct ip6_recvpktopts opts6;
-
+ /*
+ * Radar 3529618
+ * This is the second part of the MSS DoS prevention code (after
+ * minmss on the sending side) and it deals with too many too small
+ * tcp packets in a too short timeframe (1 second).
+ *
+ * For every full second we count the number of received packets
+ * and bytes. If we get a lot of packets per second for this connection
+ * (tcp_minmssoverload) we take a closer look at it and compute the
+ * average packet size for the past second. If that is less than
+ * tcp_minmss we get too many packets with very small payload which
+ * is not good and burdens our system (and every packet generates
+ * a wakeup to the process connected to our socket). We can reasonable
+ * expect this to be small packet DoS attack to exhaust our CPU
+ * cycles.
+ *
+ * Care has to be taken for the minimum packet overload value. This
+ * value defines the minimum number of packets per second before we
+ * start to worry. This must not be too low to avoid killing for
+ * example interactive connections with many small packets like
+ * telnet or SSH.
+ *
+ * Setting either tcp_minmssoverload or tcp_minmss to "0" disables
+ * this check.
+ *
+ * Account for packet if payload packet, skip over ACK, etc.
+ */
+ if (tp->t_state == TCPS_ESTABLISHED && tlen > 0) {
+ if (TSTMP_GT(tp->rcv_reset, tcp_now)) {
+ tp->rcv_pps++;
+ tp->rcv_byps += tlen + off;
+ if (tp->rcv_byps > tp->rcv_maxbyps)
+ tp->rcv_maxbyps = tp->rcv_byps;
/*
- * 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.
+ * Setting either tcp_minmssoverload or tcp_minmss to "0" disables
+ * the check.
*/
-#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 */
+ if (tcp_minmss && tcp_minmssoverload && tp->rcv_pps > tcp_minmssoverload) {
+ if ((tp->rcv_byps / tp->rcv_pps) < tcp_minmss) {
+ char ipstrbuf[MAX_IPv6_STR_LEN];
+ printf("too many small tcp packets from "
+ "%s:%u, av. %ubyte/packet, "
+ "dropping connection\n",
+#if INET6
+ isipv6 ?
+ inet_ntop(AF_INET6, &inp->in6p_faddr, ipstrbuf,
+ sizeof(ipstrbuf)) :
#endif
+ inet_ntop(AF_INET, &inp->inp_faddr, ipstrbuf,
+ sizeof(ipstrbuf)),
+ inp->inp_fport,
+ tp->rcv_byps / tp->rcv_pps);
+ tp = tcp_drop(tp, ECONNRESET);
+/* tcpstat.tcps_minmssdrops++; */
+ goto drop;
+ }
+ }
+ } else {
+ tp->rcv_reset = tcp_now + TCP_RETRANSHZ;
+ tp->rcv_pps = 1;
+ tp->rcv_byps = tlen + off;
+ }
+
+ /* 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) {
+ tp->rcv_waitforss++;
+ }
+ if (tcp_stretch_ack_enable(tp)) {
+ 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_now)) {
+ tp->rcv_by_unackwin += (tlen + off);
+ } else {
+ tp->rcv_unackwin = tcp_now + tcp_rcvunackwin;
+ tp->rcv_by_unackwin = tlen + off;
+ }
+ }
+
+ /*
+ 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 (ip_ecn == IPTOS_ECN_CE && tp->t_state == TCPS_ESTABLISHED &&
+ (tp->ecn_flags & (TE_SETUPSENT | TE_SETUPRECEIVED)) ==
+ (TE_SETUPSENT | TE_SETUPRECEIVED) && tlen > 0 &&
+ SEQ_GEQ(th->th_seq, tp->last_ack_sent) &&
+ SEQ_LT(th->th_seq, tp->last_ack_sent + tp->rcv_wnd)) {
+ tp->ecn_flags |= TE_SENDECE;
+ }
+
+ /*
+ 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_CWR) == TH_CWR) {
+ tp->ecn_flags &= ~TE_SENDECE;
}
-#endif /* INET6 */
+ /* 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.
+ */
+ if (tp->t_state == TCPS_ESTABLISHED && (tp->t_flags & TF_STRETCHACK) != 0 &&
+ ((ip_ecn == IPTOS_ECN_CE) || ((thflags & TH_CWR) == TH_CWR)))
+ tcp_reset_stretch_ack(tp);
+
/*
* Segment received on connection.
* Reset idle time and keep-alive timer.
*/
- tp->t_idle = 0;
+ tp->t_rcvtime = tcp_now;
if (TCPS_HAVEESTABLISHED(tp->t_state))
- tp->t_timer[TCPT_KEEP] = tcp_keepidle;
+ tp->t_timer[TCPT_KEEP] = OFFSET_FROM_START(tp, TCP_KEEPIDLE(tp));
/*
* 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 */
+ tcp_dooptions(tp, optp, optlen, th, &to, ifscope);
+
+ if (tp->t_state == TCPS_SYN_SENT && (thflags & TH_SYN)) {
+ if (to.to_flags & TOF_SCALE) {
+ tp->t_flags |= TF_RCVD_SCALE;
+ tp->requested_s_scale = to.to_requested_s_scale;
+ tp->snd_wnd = th->th_win << tp->snd_scale;
+ tiwin = tp->snd_wnd;
+ }
+ 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 (tp->sack_enable) {
+ if (!(to.to_flags & TOF_SACK))
+ tp->sack_enable = 0;
+ else
+ tp->t_flags |= TF_SACK_PERMIT;
+ }
+ }
+
+#if TRAFFIC_MGT
+ /* 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.
+ */
+ 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)) {
+ if (tp->iaj_pktcnt <= IAJ_IGNORE_PKTCNT) {
+ tp->iaj_pktcnt++;
+ }
+
+ if ( tp->iaj_size == 0 || tlen > tp->iaj_size ||
+ (tlen == 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, tlen, 0);
+ } else {
+ if (tlen == tp->iaj_size) {
+ /* Compute inter-arrival jitter taking this packet
+ * as the second packet
+ */
+ compute_iaj(tp);
+ }
+ if (tlen < 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.
+ */
+ tp->iaj_small_pkt++;
+ if (tp->iaj_small_pkt > RESET_IAJ_SIZE_THRESH) {
+ update_iaj_state(tp, tlen, 1);
+ } else {
+ clear_iaj_state(tp);
+ }
+ } else {
+ update_iaj_state(tp, tlen, 0);
+ }
+ }
+ } else {
+ clear_iaj_state(tp);
+ }
+#endif /* TRAFFIC_MGT */
/*
* Header prediction: check for the two common cases
* be TH_NEEDSYN.
*/
if (tp->t_state == TCPS_ESTABLISHED &&
- (thflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ACK)) == TH_ACK &&
+ (thflags & (TH_SYN|TH_FIN|TH_RST|TH_URG|TH_ACK|TH_ECE)) == TH_ACK &&
((tp->t_flags & (TF_NEEDSYN|TF_NEEDFIN)) == 0) &&
- ((to.to_flag & TOF_TS) == 0 ||
+ ((to.to_flags & 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) {
* NOTE that the test is modified according to the latest
* proposal of the tcplw@cray.com list (Braden 1993/04/26).
*/
- if ((to.to_flag & TOF_TS) != 0 &&
+ 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;
}
- if (tilen == 0) {
+ /* Force acknowledgment if we received a FIN */
+
+ if (thflags & TH_FIN)
+ tp->t_flags |= TF_ACKNOW;
+
+ 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_wnd &&
- tp->t_dupacks < tcprexmtthresh) {
+ tp->snd_cwnd >= tp->snd_ssthresh &&
+ (!IN_FASTRECOVERY(tp) &&
+ ((!tp->sack_enable && tp->t_dupacks < tcprexmtthresh) ||
+ (tp->sack_enable && to.to_nsacks == 0 &&
+ TAILQ_EMPTY(&tp->snd_holes))))) {
/*
* this is a pure ack for outstanding data.
*/
++tcpstat.tcps_predack;
- if ((to.to_flag & TOF_TS) != 0)
+ /*
+ * "bad retransmit" recovery
+ */
+ if (tp->t_rxtshift == 1 &&
+ TSTMP_LT(tcp_now, tp->t_badrxtwin)) {
+ ++tcpstat.tcps_sndrexmitbad;
+ tp->snd_cwnd = tp->snd_cwnd_prev;
+ tp->snd_ssthresh =
+ tp->snd_ssthresh_prev;
+ tp->snd_recover = tp->snd_recover_prev;
+ if (tp->t_flags & TF_WASFRECOVERY)
+ ENTER_FASTRECOVERY(tp);
+ tp->snd_nxt = tp->snd_max;
+ tp->t_badrxtwin = 0;
+ tp->t_rxtshift = 0;
+ tp->rxt_start = 0;
+ DTRACE_TCP5(cc, void, NULL, struct inpcb *, tp->t_inpcb,
+ struct tcpcb *, tp, struct tcphdr *, th,
+ int32_t, TCP_CC_BAD_REXMT_RECOVERY);
+ }
+ /*
+ * Recalculate the transmit timer / rtt.
+ *
+ * Some boxes send broken timestamp replies
+ * during the SYN+ACK phase, ignore
+ * timestamps of 0 or we could calculate a
+ * huge RTT and blow up the retransmit timer.
+ */
+ 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 + 1);
- else if (tp->t_rtt &&
- SEQ_GT(th->th_ack, tp->t_rtseq))
- tcp_xmit_timer(tp, tp->t_rtt);
+ tcp_now - to.to_tsecr);
+ } else if (tp->t_rtttime &&
+ SEQ_GT(th->th_ack, tp->t_rtseq)) {
+ tcp_xmit_timer(tp, tcp_now - tp->t_rtttime);
+ }
acked = th->th_ack - tp->snd_una;
tcpstat.tcps_rcvackpack++;
tcpstat.tcps_rcvackbyte += acked;
+
+ /* 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)->inseq_ack_rcvd != NULL)
+ CC_ALGO(tp)->inseq_ack_rcvd(tp, th);
+
+ DTRACE_TCP5(cc, void, NULL, struct inpcb *, inp,
+ struct tcpcb *, tp, struct tcphdr *, th,
+ int32_t, TCP_CC_INSEQ_ACK_RCVD);
+
sbdrop(&so->so_snd, acked);
+ 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;
+ /*
+ * pull snd_wl2 up to prevent seq wrap relative
+ * to th_ack.
+ */
+ tp->snd_wl2 = th->th_ack;
+ tp->t_dupacks = 0;
m_freem(m);
-#if INET6
- /* some progress has been done */
- if (isipv6)
- ND6_HINT(tp);
-#endif
+ ND6_HINT(tp); /* some progress has been done */
/*
* If all outstanding data are acked, stop
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;
+ tp->t_timer[TCPT_REXMT] = OFFSET_FROM_START(tp, tp->t_rxtcur);
- if (so->so_snd.sb_cc)
+ sowwakeup(so); /* has to be done with socket lock held */
+ if ((so->so_snd.sb_cc) || (tp->t_flags & TF_ACKNOW)) {
(void) tcp_output(tp);
- sowwakeup(so);
+ }
+
+ tcp_check_timer_state(tp);
+ tcp_unlock(so, 1, 0);
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)) {
+ 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.
*/
+ /* Clean receiver SACK report if present */
+ if (tp->sack_enable && tp->rcv_numsacks)
+ tcp_clean_sackreport(tp);
++tcpstat.tcps_preddat;
- tp->rcv_nxt += tilen;
+ 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;
tcpstat.tcps_rcvpack++;
- tcpstat.tcps_rcvbyte += tilen;
+ tcpstat.tcps_rcvbyte += tlen;
+ if (nstat_collect) {
+ locked_add_64(&inp->inp_stat->rxpackets, 1);
+ locked_add_64(&inp->inp_stat->rxbytes, tlen);
+ }
+ ND6_HINT(tp); /* some progress has been done */
+ /*
+ * Add data to socket buffer.
+ */
+ so_recv_data_stat(so, m, 0);
+ m_adj(m, drop_hdrlen); /* delayed header drop */
+ if (sbappendstream(&so->so_rcv, m))
+ sorwakeup(so);
#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;
+ 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);
+ }
+ 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);
+ }
+ tp->t_unacksegs++;
} else {
tp->t_flags |= TF_ACKNOW;
tcp_output(tp);
}
- sorwakeup(so);
+ tcp_check_timer_state(tp);
+ tcp_unlock(so, 1, 0);
KERNEL_DEBUG(DBG_FNC_TCP_INPUT | DBG_FUNC_END,0,0,0,0,0);
return;
}
* Receive window is amount of space in rcv queue,
* but not less than advertised window.
*/
+ lck_mtx_assert(&((struct inpcb *)so->so_pcb)->inpcb_mtx, LCK_MTX_ASSERT_OWNED);
+
{ int win;
- win = sbspace(&so->so_rcv);
+ 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));
}
switch (tp->t_state) {
/*
- * 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
+ * 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.
*/
case TCPS_LISTEN: {
register struct sockaddr_in *sin;
-#if 0
+#if INET6
register struct sockaddr_in6 *sin6;
#endif
- 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;
- }
-
+ lck_mtx_assert(&((struct inpcb *)so->so_pcb)->inpcb_mtx, LCK_MTX_ASSERT_OWNED);
#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;
-
- /* TODO: flowinfo initialization */
-
- in_pcbrehash(inp);
-#else
MALLOC(sin6, struct sockaddr_in6 *, sizeof *sin6,
M_SONAME, M_NOWAIT);
if (sin6 == NULL)
if (IN6_IS_ADDR_UNSPECIFIED(&inp->in6p_laddr))
inp->in6p_laddr = ip6->ip6_dst;
if (in6_pcbconnect(inp, (struct sockaddr *)sin6,
- &proc0)) {
+ proc0)) {
inp->in6p_laddr = laddr6;
FREE(sin6, M_SONAME);
goto drop;
}
FREE(sin6, M_SONAME);
+ } else
#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;
+ {
+ lck_mtx_assert(&((struct inpcb *)so->so_pcb)->inpcb_mtx, LCK_MTX_ASSERT_OWNED);
MALLOC(sin, struct sockaddr_in *, sizeof *sin, M_SONAME,
- M_NOWAIT);
+ M_NOWAIT);
if (sin == NULL)
goto drop;
sin->sin_family = AF_INET;
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)) {
+ if (in_pcbconnect(inp, (struct sockaddr *)sin, proc0, NULL)) {
inp->inp_laddr = laddr;
FREE(sin, M_SONAME);
goto drop;
}
FREE(sin, M_SONAME);
-#if INET6
}
-#endif /* INET6 */
- 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));
+ tcp_dooptions(tp, optp, optlen, th, &to, ifscope);
+
+ if (tp->sack_enable) {
+ if (!(to.to_flags & TOF_SACK))
+ tp->sack_enable = 0;
+ else
+ tp->t_flags |= TF_SACK_PERMIT;
}
- 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;
+ 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->cc_send = CC_INC(tcp_ccgen);
- tp->cc_recv = to.to_cc;
- /*
- * 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++;
-
- tp->t_state = TCPS_ESTABLISHED;
-
- /*
- * 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)
-#if INET6
- )
-#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);
- }
- 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;
- }
- /*
- * TAO test failed or there was no CC option,
- * do a standard 3-way handshake.
- */
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] = tcp_keepinit;
+ tp->t_timer[TCPT_KEEP] = OFFSET_FROM_START(tp,
+ tp->t_keepinit ? tp->t_keepinit : tcp_keepinit);
dropsocket = 0; /* committed to socket */
+
+ /* 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);
+ }
+#if CONFIG_IFEF_NOWINDOWSCALE
+ if (tcp_obey_ifef_nowindowscale && m->m_pkthdr.rcvif != NULL &&
+ (m->m_pkthdr.rcvif->if_eflags & IFEF_NOWINDOWSCALE)) {
+ /* Window scaling is not enabled on this interface */
+ tp->t_flags &= ~TF_REQ_SCALE;
+ }
+#endif
goto trimthenstep6;
}
case TCPS_SYN_RECEIVED:
if ((thflags & TH_ACK) &&
(SEQ_LEQ(th->th_ack, tp->snd_una) ||
- SEQ_GT(th->th_ack, tp->snd_max)))
+ SEQ_GT(th->th_ack, tp->snd_max))) {
+ rstreason = BANDLIM_RST_OPENPORT;
goto dropwithreset;
+ }
break;
/*
* continue processing rest of data/controls, beginning with URG
*/
case TCPS_SYN_SENT:
- if ((taop = tcp_gettaocache(inp)) == NULL) {
- taop = &tao_noncached;
- bzero(taop, sizeof(*taop));
- }
-
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;
+ rstreason = BANDLIM_UNLIMITED;
+ goto dropwithreset;
}
if (thflags & TH_RST) {
- if (thflags & TH_ACK) {
+ if ((thflags & TH_ACK) != 0) {
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 */
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);
+
+ if ((thflags & (TH_ECE | TH_CWR)) == (TH_ECE)) {
+ /* ECN-setup SYN-ACK */
+ tp->ecn_flags |= TE_SETUPRECEIVED;
+ }
+ else {
+ /* 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 ((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;
-
tp->rcv_adv += tp->rcv_wnd;
tp->snd_una++; /* SYN is acked */
/*
* If there's data, delay ACK; if there's also a FIN
* ACKNOW will be turned on later.
*/
- 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;
+ 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);
+ }
+ tp->t_unacksegs++;
}
- else
+ 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;
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;
} else {
- if (tp->t_state != TCPS_ESTABLISHED)
- current_active_connections++;
+ 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] = tcp_keepidle;
+ tp->t_timer[TCPT_KEEP] = OFFSET_FROM_START(tp, TCP_KEEPIDLE(tp));
+ if (nstat_collect)
+ nstat_route_connect_success(tp->t_inpcb->inp_route.ro_rt);
}
+ isconnected = TRUE;
} 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.
- */
+ /*
+ * 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;
- 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;
- } else {
- /* CC.NEW or no option => invalidate cache */
- taop->tao_cc = 0;
- tp->t_state = TCPS_SYN_RECEIVED;
- }
+ DTRACE_TCP4(state__change, void, NULL, struct inpcb *, inp,
+ struct tcpcb *, tp, int32_t, TCPS_SYN_RECEIVED);
+ tp->t_state = TCPS_SYN_RECEIVED;
+
}
trimthenstep6:
* dropping FIN if necessary.
*/
th->th_seq++;
- if (tilen > tp->rcv_wnd) {
- todrop = tilen - tp->rcv_wnd;
+ if (tlen > tp->rcv_wnd) {
+ todrop = tlen - tp->rcv_wnd;
m_adj(m, -todrop);
- tilen = tp->rcv_wnd;
+ tlen = tp->rcv_wnd;
thflags &= ~TH_FIN;
tcpstat.tcps_rcvpackafterwin++;
tcpstat.tcps_rcvbyteafterwin += todrop;
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;
+ * do normal processing.
*
- * else must be old SYN; drop it.
- * else 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:
- 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 */
+
+ /* 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 numberering
+ */
+ case TCPS_ESTABLISHED:
+ if (thflags & TH_SYN)
+ goto dropafterack;
+ break;
}
/*
* 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.
+ * 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.
* 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.
* 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:
+ * ESTABLISHED, FIN_WAIT_1, FIN_WAIT_2, CLOSE_WAIT STATES:
* Inform user that connection was reset, and close tcb.
- * CLOSING, LAST_ACK, TIME_WAIT STATES
+ * CLOSING, LAST_ACK STATES:
* Close the tcb.
- * TIME_WAIT state:
+ * 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 (tp->last_ack_sent == th->th_seq) {
+ 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)))) {
switch (tp->t_state) {
case TCPS_SYN_RECEIVED:
goto close;
case TCPS_ESTABLISHED:
+ if (tp->last_ack_sent != th->th_seq) {
+ tcpstat.tcps_badrst++;
+ goto drop;
+ }
case TCPS_FIN_WAIT_1:
case TCPS_CLOSE_WAIT:
- current_active_connections--;
/*
Drop through ...
*/
so->so_error = ECONNRESET;
close:
postevent(so, 0, EV_RESET);
+ DTRACE_TCP4(state__change, void, NULL, struct inpcb *, inp,
+ struct tcpcb *, tp, int32_t, TCPS_CLOSED);
tp->t_state = TCPS_CLOSED;
tcpstat.tcps_drops++;
tp = tcp_close(tp);
case TCPS_CLOSING:
case TCPS_LAST_ACK:
- current_active_connections--;
tp = tcp_close(tp);
break;
* 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 &&
+ 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. */
tp->ts_recent = 0;
} else {
tcpstat.tcps_rcvduppack++;
- tcpstat.tcps_rcvdupbyte += tilen;
+ tcpstat.tcps_rcvdupbyte += tlen;
tcpstat.tcps_pawsdrop++;
- goto dropafterack;
+ if (nstat_collect) {
+ nstat_route_rx(tp->t_inpcb->inp_route.ro_rt, 1, tlen, NSTAT_RX_FLAG_DUPLICATE);
+ locked_add_64(&inp->inp_stat->rxpackets, 1);
+ locked_add_64(&inp->inp_stat->rxbytes, tlen);
+ tp->t_stat.rxduplicatebytes += tlen;
+ }
+ if (tlen)
+ goto dropafterack;
+ goto drop;
}
}
- /*
- * 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
* 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))
+ if (tp->t_state == TCPS_SYN_RECEIVED && SEQ_LT(th->th_seq, tp->irs)) {
+ rstreason = BANDLIM_RST_OPENPORT;
goto dropwithreset;
+ }
todrop = tp->rcv_nxt - th->th_seq;
if (todrop > 0) {
/*
* Following if statement from Stevens, vol. 2, p. 960.
*/
- if (todrop > tilen
- || (todrop == tilen && (thflags & TH_FIN) == 0)) {
+ 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
* But keep on processing for RST or ACK.
*/
tp->t_flags |= TF_ACKNOW;
- todrop = tilen;
+ todrop = tlen;
tcpstat.tcps_rcvduppack++;
tcpstat.tcps_rcvdupbyte += todrop;
} else {
tcpstat.tcps_rcvpartduppack++;
tcpstat.tcps_rcvpartdupbyte += todrop;
}
- m_adj(m, todrop);
+ if (nstat_collect) {
+ nstat_route_rx(tp->t_inpcb->inp_route.ro_rt, 1, todrop, NSTAT_RX_FLAG_DUPLICATE);
+ locked_add_64(&inp->inp_stat->rxpackets, 1);
+ locked_add_64(&inp->inp_stat->rxbytes, todrop);
+ tp->t_stat.rxduplicatebytes += todrop;
+ }
+ drop_hdrlen += todrop; /* drop from the top afterwards */
th->th_seq += todrop;
- tilen -= todrop;
+ tlen -= todrop;
if (th->th_urp > todrop)
th->th_urp -= todrop;
else {
* user processes are gone, then RST the other end.
*/
if ((so->so_state & SS_NOFDREF) &&
- tp->t_state > TCPS_CLOSE_WAIT && tilen) {
+ tp->t_state > TCPS_CLOSE_WAIT && tlen) {
tp = tcp_close(tp);
tcpstat.tcps_rcvafterclose++;
+ rstreason = BANDLIM_UNLIMITED;
goto dropwithreset;
}
* 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);
+ todrop = (th->th_seq+tlen) - (tp->rcv_nxt+tp->rcv_wnd);
if (todrop > 0) {
tcpstat.tcps_rcvpackafterwin++;
- if (todrop >= tilen) {
- tcpstat.tcps_rcvbyteafterwin += tilen;
+ if (todrop >= tlen) {
+ tcpstat.tcps_rcvbyteafterwin += tlen;
/*
* If a new connection request is received
* while in TIME_WAIT, drop the old connection
if (thflags & TH_SYN &&
tp->t_state == TCPS_TIME_WAIT &&
SEQ_GT(th->th_seq, tp->rcv_nxt)) {
- iss = tp->rcv_nxt + TCP_ISSINCR;
+ iss = tcp_new_isn(tp);
tp = tcp_close(tp);
+ tcp_unlock(so, 1, 0);
goto findpcb;
}
/*
} else
tcpstat.tcps_rcvbyteafterwin += todrop;
m_adj(m, -todrop);
- tilen -= todrop;
+ tlen -= todrop;
thflags &= ~(TH_PUSH|TH_FIN);
}
/*
* 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).
+ * 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_flag & TOF_TS) != 0 &&
- SEQ_LEQ(th->th_seq, tp->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;
}
*/
if (thflags & TH_SYN) {
tp = tcp_drop(tp, ECONNRESET);
+ rstreason = BANDLIM_UNLIMITED;
postevent(so, 0, EV_RESET);
goto dropwithreset;
}
if (tp->t_state == TCPS_SYN_RECEIVED ||
(tp->t_flags & TF_NEEDSYN))
goto step6;
+ else if (tp->t_flags & TF_ACKNOW)
+ goto dropafterack;
else
goto drop;
}
case TCPS_SYN_RECEIVED:
tcpstat.tcps_connects++;
- soisconnected(so);
- current_active_connections++;
/* 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;
+ tp->snd_wnd = th->th_win << tp->snd_scale;
+ tiwin = tp->snd_wnd;
}
- /*
- * 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
*/
+ tp->t_starttime = tcp_now;
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;
} 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] = tcp_keepidle;
+ tp->t_timer[TCPT_KEEP] = OFFSET_FROM_START(tp, TCP_KEEPIDLE(tp));
+ if (nstat_collect)
+ nstat_route_connect_success(tp->t_inpcb->inp_route.ro_rt);
}
/*
* 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);
+ if (tlen == 0 && (thflags & TH_FIN) == 0)
+ (void) tcp_reass(tp, (struct tcphdr *)0, &tlen,
+ (struct mbuf *)0);
tp->snd_wl1 = th->th_seq - 1;
- /* fall into ... */
+
+ /* FALLTHROUGH */
+
+ isconnected = TRUE;
/*
* In ESTABLISHED state: drop duplicate ACKs; ACK out of range
case TCPS_CLOSING:
case TCPS_LAST_ACK:
case TCPS_TIME_WAIT:
-
+ if (SEQ_GT(th->th_ack, tp->snd_max)) {
+ tcpstat.tcps_rcvacktoomuch++;
+ goto dropafterack;
+ }
+ if (tp->sack_enable &&
+ (to.to_nsacks > 0 || !TAILQ_EMPTY(&tp->snd_holes)))
+ tcp_sack_doack(tp, &to, th->th_ack);
if (SEQ_LEQ(th->th_ack, tp->snd_una)) {
- if (tilen == 0 && tiwin == tp->snd_wnd) {
+ if (tlen == 0 && tiwin == tp->snd_wnd) {
tcpstat.tcps_rcvdupack++;
/*
* If we have outstanding data (other than
if (tp->t_timer[TCPT_REXMT] == 0 ||
th->th_ack != tp->snd_una)
tp->t_dupacks = 0;
- else if (++tp->t_dupacks == tcprexmtthresh) {
+ else if (++tp->t_dupacks > tcprexmtthresh ||
+ IN_FASTRECOVERY(tp)) {
+ if (tp->sack_enable && 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;
+
+ DTRACE_TCP5(cc, void, NULL, struct inpcb *, inp,
+ struct tcpcb *, tp, struct tcphdr *, th,
+ int32_t, TCP_CC_IN_FASTRECOVERY);
+
+ (void) tcp_output(tp);
+ goto drop;
+ } 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;
+ /*
+ * 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 (tp->sack_enable) {
+ if (IN_FASTRECOVERY(tp)) {
+ tp->t_dupacks = 0;
+ break;
+ }
+ } else {
+ if (SEQ_LEQ(th->th_ack,
+ tp->snd_recover)) {
+ tp->t_dupacks = 0;
+ break;
+ }
+ }
+
+ /*
+ * 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, th);
+ ENTER_FASTRECOVERY(tp);
+ tp->snd_recover = tp->snd_max;
tp->t_timer[TCPT_REXMT] = 0;
- tp->t_rtt = 0;
+ tp->t_rtttime = 0;
+ tp->ecn_flags |= TE_SENDCWR;
+ if (tp->sack_enable) {
+ tcpstat.tcps_sack_recovery_episode++;
+ tp->sack_newdata = tp->snd_nxt;
+ tp->snd_cwnd = tp->t_maxseg;
+
+ DTRACE_TCP5(cc, void, NULL, struct inpcb *, inp,
+ struct tcpcb *, tp, struct tcphdr *, th,
+ int32_t, TCP_CC_ENTER_FASTRECOVERY);
+
+ (void) tcp_output(tp);
+ goto drop;
+ }
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;
+ 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);
+ DTRACE_TCP5(cc, void, NULL, struct inpcb *, inp,
+ struct tcpcb *, tp, struct tcphdr *, th,
+ int32_t, TCP_CC_ENTER_FASTRECOVERY);
goto drop;
}
} else
* 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 (IN_FASTRECOVERY(tp)) {
+ if (SEQ_LT(th->th_ack, tp->snd_recover)) {
+ if (tp->sack_enable)
+ tcp_sack_partialack(tp, th);
+ else
+ tcp_newreno_partial_ack(tp, th);
+
+ DTRACE_TCP5(cc, void, NULL, struct inpcb *, inp,
+ struct tcpcb *, tp, struct tcphdr *, th,
+ int32_t, TCP_CC_PARTIAL_ACK);
+ } else {
+ EXIT_FASTRECOVERY(tp);
+ if (CC_ALGO(tp)->post_fr != NULL)
+ CC_ALGO(tp)->post_fr(tp, th);
+ tp->t_dupacks = 0;
+
+ DTRACE_TCP5(cc, void, NULL, struct inpcb *, inp,
+ struct tcpcb *, tp, struct tcphdr *, th,
+ int32_t, TCP_CC_EXIT_FASTRECOVERY);
+ }
+ } else {
+ /*
+ * We were not in fast recovery. Reset the duplicate ack
+ * counter.
+ */
+ tp->t_dupacks = 0;
}
+
+
/*
- * If we reach this point, ACK is not a duplicate,
+ * If we reach this point, ACK is not a duplicate,
* i.e., it ACKs something we sent.
*/
if (tp->t_flags & TF_NEEDSYN) {
tcpstat.tcps_rcvackpack++;
tcpstat.tcps_rcvackbyte += acked;
+ /*
+ * If we just performed our first retransmit, and the ACK
+ * arrives within our recovery window, then it was a mistake
+ * to do the retransmit in the first place. Recover our
+ * original cwnd and ssthresh, and proceed to transmit where
+ * we left off.
+ */
+ if (tp->t_rxtshift == 1 &&
+ TSTMP_LT(tcp_now, tp->t_badrxtwin)) {
+ ++tcpstat.tcps_sndrexmitbad;
+ tp->snd_cwnd = tp->snd_cwnd_prev;
+ tp->snd_ssthresh = tp->snd_ssthresh_prev;
+ tp->snd_recover = tp->snd_recover_prev;
+ if (tp->t_flags & TF_WASFRECOVERY)
+ ENTER_FASTRECOVERY(tp);
+ tp->snd_nxt = tp->snd_max;
+ tp->t_badrxtwin = 0; /* XXX probably not required */
+ tp->t_rxtshift = 0;
+ tp->rxt_start = 0;
+
+ DTRACE_TCP5(cc, void, NULL, struct inpcb *, inp,
+ struct tcpcb *, tp, struct tcphdr *, th,
+ int32_t, TCP_CC_BAD_REXMT_RECOVERY);
+ }
+
/*
* If we have a timestamp reply, update smoothed
* round trip time. If no timestamp is present but
* Since we now have an rtt measurement, cancel the
* timer backoff (cf., Phil Karn's retransmit alg.).
* Recompute the initial retransmit timer.
+ * Also makes sure we have a valid time stamp in hand
+ *
+ * Some boxes send broken timestamp replies
+ * during the SYN+ACK phase, ignore
+ * timestamps of 0 or we could calculate a
+ * huge RTT and blow up the 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);
+ 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);
+ } else if (tp->t_rtttime && SEQ_GT(th->th_ack, tp->t_rtseq)) {
+ tcp_xmit_timer(tp, tcp_now - tp->t_rtttime);
+ }
/*
* If all outstanding data is acked, stop retransmit
tp->t_timer[TCPT_REXMT] = 0;
needoutput = 1;
} else if (tp->t_timer[TCPT_PERSIST] == 0)
- tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;
+ tp->t_timer[TCPT_REXMT] = OFFSET_FROM_START(tp, tp->t_rxtcur);
/*
* If no data (only SYN) was ACK'd,
if (acked == 0)
goto step6;
+ if ((thflags & TH_ECE) != 0 &&
+ (tp->ecn_flags & TE_SETUPSENT) != 0) {
+ /*
+ * Reduce the congestion window if we haven't done so.
+ */
+ if (!tp->sack_enable && !IN_FASTRECOVERY(tp) &&
+ SEQ_GEQ(th->th_ack, tp->snd_recover)) {
+ tcp_reduce_congestion_window(tp, th);
+ DTRACE_TCP5(cc, void, NULL, struct inpcb *, inp,
+ struct tcpcb *, tp, struct tcphdr *, th,
+ int32_t, TCP_CC_ECN_RCVD);
+ }
+ }
+
/*
* 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).
+ * 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.
*/
- {
- register u_int cw = tp->snd_cwnd;
- register u_int incr = tp->t_maxseg;
-
- if (cw > tp->snd_ssthresh)
- incr = incr * incr / cw;
- tp->snd_cwnd = min(cw + incr, TCP_MAXWIN<<tp->snd_scale);
+ if (!IN_FASTRECOVERY(tp)) {
+ if (CC_ALGO(tp)->ack_rcvd != NULL)
+ CC_ALGO(tp)->ack_rcvd(tp, th);
+
+ DTRACE_TCP5(cc, void, NULL, struct inpcb *, inp,
+ struct tcpcb *, tp, struct tcphdr *, th,
+ int32_t, TCP_CC_ACK_RCVD);
}
if (acked > so->so_snd.sb_cc) {
tp->snd_wnd -= so->so_snd.sb_cc;
tp->snd_wnd -= acked;
ourfinisacked = 0;
}
- need_sowwakeup++;
+ /* 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 (tp->sack_enable) {
+ 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;
+
+ /*
+ * sowwakeup must happen after snd_una, et al. are updated so that
+ * the sequence numbers are in sync with so_snd
+ */
+ sowwakeup(so);
switch (tp->t_state) {
* we'll hang forever.
*/
if (so->so_state & SS_CANTRCVMORE) {
- soisdisconnected(so);
- tp->t_timer[TCPT_2MSL] = tcp_maxidle;
+ add_to_time_wait(tp, tcp_maxidle);
+ isconnected = FALSE;
+ isdisconnected = TRUE;
}
- add_to_time_wait(tp);
- current_active_connections--;
+ 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 */
}
+ tp->t_flags |= TF_ACKNOW;
break;
/*
*/
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);
/* 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;
+ ((int)(tcp_now - tp->t_starttime)) < tcp_msl)
+ add_to_time_wait(tp, tp->t_rxtcur * TCPTV_TWTRUNC);
else
- tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
- add_to_time_wait(tp);
- current_active_connections--;
- soisdisconnected(so);
+ add_to_time_wait(tp, 2 * tcp_msl);
+ isconnected = FALSE;
+ isdisconnected = TRUE;
}
+ tp->t_flags |= TF_ACKNOW;
break;
/*
* it and restart the finack timer.
*/
case TCPS_TIME_WAIT:
- tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
- add_to_time_wait(tp);
+ add_to_time_wait(tp, 2 * tcp_msl);
goto dropafterack;
}
}
(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 &&
+ if (tlen == 0 &&
tp->snd_wl2 == th->th_ack && tiwin > tp->snd_wnd)
tcpstat.tcps_rcvwinupd++;
tp->snd_wnd = tiwin;
* 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 (th->th_urp <= (u_int32_t)tlen
#if SO_OOBINLINE
&& (so->so_options & SO_OOBINLINE) == 0
#endif
)
- tcp_pulloutofband(so, th, m);
- } else
+ 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
*/
if (SEQ_GT(tp->rcv_nxt, tp->rcv_up))
tp->rcv_up = tp->rcv_nxt;
-dodata: /* XXX */
+ }
+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 */
+ goto drop;
+ }
+
/*
* Process the segment text, merging it into the TCP sequencing queue,
* and arranging for acknowledgment of receipt if necessary.
* case PRU_RCVD). If a FIN has already been received on this
* connection then we just ignore the text.
*/
- if ((tilen || (thflags&TH_FIN)) &&
+ if ((tlen || (thflags & TH_FIN)) &&
TCPS_HAVERCVDFIN(tp->t_state) == 0) {
- TCP_REASS(tp, th, tilen, m, so, thflags, isipv6, need_sorwakeup);
+ 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) &&
+ TCPS_HAVEESTABLISHED(tp->t_state)) {
+ 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);
+ }
+ tp->t_unacksegs++;
+ }
+ else {
+ tp->t_flags |= TF_ACKNOW;
+ }
+ tp->rcv_nxt += tlen;
+ thflags = th->th_flags & TH_FIN;
+ tcpstat.tcps_rcvpack++;
+ tcpstat.tcps_rcvbyte += tlen;
+ if (nstat_collect) {
+ locked_add_64(&inp->inp_stat->rxpackets, 1);
+ locked_add_64(&inp->inp_stat->rxbytes, tlen);
+ }
+ ND6_HINT(tp);
+ so_recv_data_stat(so, m, drop_hdrlen);
+ if (sbappendstream(&so->so_rcv, m))
+ sorwakeup(so);
+ } else {
+ thflags = tcp_reass(tp, th, &tlen, m);
+ tp->t_flags |= TF_ACKNOW;
+ }
+
+ if (tlen > 0 && tp->sack_enable)
+ tcp_update_sack_list(tp, save_start, save_end);
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);
+#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);
+ }
+
}
/*
* 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);
+ len = (u_int)(so->so_rcv.sb_hiwat - (tp->rcv_adv - tp->rcv_nxt));
+ if (len > so->so_rcv.sb_maxused)
+ so->so_rcv.sb_maxused = len;
} else {
m_freem(m);
thflags &= ~TH_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 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);
-
- tp->t_flags |= TF_DELACK;
+ 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);
+ }
+ tp->t_unacksegs++;
}
- else
+ else {
tp->t_flags |= TF_ACKNOW;
+ }
tp->rcv_nxt++;
}
switch (tp->t_state) {
* 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;
* 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;
* 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);
/* 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;
+ ((int)(tcp_now - tp->t_starttime)) < tcp_msl) {
+ add_to_time_wait(tp, tp->t_rxtcur * TCPTV_TWTRUNC);
/* For transaction client, force ACK now. */
tp->t_flags |= TF_ACKNOW;
+ tp->t_unacksegs = 0;
}
else
- tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
-
- add_to_time_wait(tp);
+ 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:
- tp->t_timer[TCPT_2MSL] = 2 * TCPTV_MSL;
- add_to_time_wait(tp);
+ add_to_time_wait(tp, 2 * tcp_msl);
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,
+ if (so->so_options & SO_DEBUG)
+ tcp_trace(TA_INPUT, ostate, tp, (void *)tcp_saveipgen,
&tcp_savetcp, 0);
- }
#endif
/*
* Return any desired output.
*/
- if (needoutput || (tp->t_flags & TF_ACKNOW))
+ if (needoutput || (tp->t_flags & TF_ACKNOW)) {
(void) tcp_output(tp);
- if (need_sorwakeup)
- sorwakeup(so);
- if (need_sowwakeup)
- sowwakeup(so);
+ }
+
+ tcp_check_timer_state(tp);
+
+
+ tcp_unlock(so, 1, 0);
KERNEL_DEBUG(DBG_FNC_TCP_INPUT | DBG_FUNC_END,0,0,0,0,0);
return;
*/
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)) )
+ SEQ_GT(th->th_ack, tp->snd_max)) ) {
+ rstreason = BANDLIM_RST_OPENPORT;
goto dropwithreset;
+ }
#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_DROP, ostate, tp, (void *)&tcp_saveip,
+ 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);
- if (need_sorwakeup)
- sorwakeup(so);
- if (need_sowwakeup)
- sowwakeup(so);
+
+ /* Don't need to check timer state as we should have done it during tcp_output */
+ tcp_unlock(so, 1, 0);
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.
goto drop;
#if INET6
if (isipv6) {
- if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst))
- goto drop; /* anycast check is done at the top */
+ 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)))
+ 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;
-#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,
+ /* 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
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);
-#endif /* INET6 */
+ /* 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, ifscope, nocell);
else {
if (thflags & TH_SYN)
- tilen++;
-#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);
-#endif /* INET6 */
+ 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, ifscope, nocell);
}
/* destroy temporarily created socket */
- if (need_sorwakeup)
- sorwakeup(so);
- if (need_sowwakeup)
- sowwakeup(so);
- if (dropsocket)
- (void) soabort(so);
+ if (dropsocket) {
+ (void) soabort(so);
+ tcp_unlock(so, 1, 0);
+ }
+ else if ((inp != NULL) && (nosock == 0)) {
+ tcp_unlock(so, 1, 0);
+ }
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)) {
- 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,
+ 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);
- if (need_sorwakeup)
- sorwakeup(so);
- if (need_sowwakeup)
- sowwakeup(so);
/* destroy temporarily created socket */
- if (dropsocket)
- (void) soabort(so);
+ if (dropsocket) {
+ (void) soabort(so);
+ tcp_unlock(so, 1, 0);
+ }
+ else if (nosock == 0) {
+ tcp_unlock(so, 1, 0);
+ }
KERNEL_DEBUG(DBG_FNC_TCP_INPUT | DBG_FUNC_END,0,0,0,0,0);
return;
}
static void
-tcp_dooptions(tp, cp, cnt, th, to)
+tcp_dooptions(tp, cp, cnt, th, to, input_ifscope)
+/*
+ * Parse TCP options and place in tcpopt.
+ */
struct tcpcb *tp;
u_char *cp;
int cnt;
struct tcphdr *th;
struct tcpopt *to;
+ unsigned int input_ifscope;
{
u_short mss = 0;
int opt, optlen;
if (opt == TCPOPT_NOP)
optlen = 1;
else {
+ if (cnt < 2)
+ break;
optlen = cp[1];
- if (optlen <= 0)
+ if (optlen < 2 || optlen > cnt)
break;
}
switch (opt) {
if (!(th->th_flags & TH_SYN))
continue;
bcopy((char *) cp + 2, (char *) &mss, sizeof(mss));
- to->to_maxseg = ntohs(mss);
+
+#if BYTE_ORDER != BIG_ENDIAN
+ NTOHS(mss);
+#endif
+
break;
case TCPOPT_WINDOW:
case TCPOPT_TIMESTAMP:
if (optlen != TCPOLEN_TIMESTAMP)
continue;
- to->to_flag |= TOF_TS;
+ to->to_flags |= TOF_TS;
bcopy((char *)cp + 2,
(char *)&to->to_tsval, sizeof(to->to_tsval));
+
+#if BYTE_ORDER != BIG_ENDIAN
NTOHL(to->to_tsval);
+#endif
+
bcopy((char *)cp + 6,
(char *)&to->to_tsecr, sizeof(to->to_tsecr));
+
+#if BYTE_ORDER != BIG_ENDIAN
NTOHL(to->to_tsecr);
+#endif
/*
* A timestamp received in a SYN makes
tp->ts_recent_age = tcp_now;
}
break;
- case TCPOPT_CC:
- if (optlen != TCPOLEN_CC)
+ case TCPOPT_SACK_PERMITTED:
+ if (!tcp_do_sack ||
+ optlen != TCPOLEN_SACK_PERMITTED)
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.
- */
- tp->t_flags |= TF_RCVD_CC;
+ to->to_flags |= TOF_SACK;
break;
- case TCPOPT_CCECHO:
- if (optlen != TCPOLEN_CC)
+ case TCPOPT_SACK:
+ if (optlen <= 2 || (optlen - 2) % TCPOLEN_SACK != 0)
continue;
- if (!(th->th_flags & TH_SYN))
- continue;
- to->to_flag |= TOF_CCECHO;
- bcopy((char *)cp + 2,
- (char *)&to->to_ccecho, sizeof(to->to_ccecho));
- NTOHL(to->to_ccecho);
+ to->to_nsacks = (optlen - 2) / TCPOLEN_SACK;
+ to->to_sacks = cp + 2;
+ tcpstat.tcps_sack_rcv_blocks++;
+
break;
}
}
+ if (th->th_flags & TH_SYN)
+ tcp_mss(tp, mss, input_ifscope); /* sets t_maxseg */
}
/*
* sequencing purposes.
*/
static void
-tcp_pulloutofband(so, th, m)
+tcp_pulloutofband(so, th, m, off)
struct socket *so;
struct tcphdr *th;
register struct mbuf *m;
+ int off; /* delayed to be droped hdrlen */
{
- int cnt = th->th_urp - 1;
+ int cnt = off + th->th_urp - 1;
while (cnt >= 0) {
if (m->m_len > cnt) {
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;
panic("tcp_pulloutofband");
}
+uint32_t
+get_base_rtt(struct tcpcb *tp)
+{
+ uint32_t base_rtt = 0, i;
+ for (i = 0; i < N_RTT_BASE; ++i) {
+ if (tp->rtt_hist[i] != 0 &&
+ (base_rtt == 0 || tp->rtt_hist[i] < base_rtt))
+ base_rtt = tp->rtt_hist[i];
+ }
+ return base_rtt;
+}
+
+/* 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)
+{
+ if (++tp->rtt_count >= rtt_samples_per_slot) {
+ int i=0;
+ for (i = (N_RTT_BASE-1); i > 0; --i) {
+ tp->rtt_hist[i] = tp->rtt_hist[i-1];
+ }
+ tp->rtt_hist[0] = rtt;
+ tp->rtt_count = 0;
+ } else {
+ tp->rtt_hist[0] = min(tp->rtt_hist[0], rtt);
+ }
+}
+
/*
* 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;
+ int rtt;
{
register int delta;
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 8). The following magic
+ * 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). Adjust rtt to origin 0.
+ * 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 - 1) << TCP_DELTA_SHIFT)
+ delta = (rtt << TCP_DELTA_SHIFT)
- (tp->t_srtt >> (TCP_RTT_SHIFT - TCP_DELTA_SHIFT));
if ((tp->t_srtt += delta) <= 0)
delta -= tp->t_rttvar >> (TCP_RTTVAR_SHIFT - TCP_DELTA_SHIFT);
if ((tp->t_rttvar += delta) <= 0)
tp->t_rttvar = 1;
+ if (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.
*/
tp->t_srtt = rtt << TCP_RTT_SHIFT;
tp->t_rttvar = rtt << (TCP_RTTVAR_SHIFT - 1);
+ tp->t_rttbest = tp->t_srtt + tp->t_rttvar;
}
- tp->t_rtt = 0;
+ nstat_route_rtt(tp->t_inpcb->inp_route.ro_rt, tp->t_srtt, tp->t_rttvar);
+ tp->t_rtttime = 0;
tp->t_rxtshift = 0;
+ tp->rxt_start = 0;
/*
* the retransmit should happen at rtt + 4 * rttvar.
* the minimum feasible timer (which is 2 ticks).
*/
TCPT_RANGESET(tp->t_rxtcur, TCP_REXMTVAL(tp),
- max(tp->t_rttmin, rtt + 2), TCPTV_REXMTMAX);
+ max(tp->t_rttmin, rtt + 2), TCPTV_REXMTMAX,
+ TCP_ADD_REXMTSLOP(tp));
/*
* We received an ack for a packet that wasn't retransmitted;
tp->t_softerror = 0;
}
+static inline unsigned int
+tcp_maxmtu(struct rtentry *rt)
+{
+ unsigned int maxmtu;
+
+ RT_LOCK_ASSERT_HELD(rt);
+ if (rt->rt_rmx.rmx_mtu == 0)
+ maxmtu = rt->rt_ifp->if_mtu;
+ else
+ maxmtu = MIN(rt->rt_rmx.rmx_mtu, rt->rt_ifp->if_mtu);
+
+ return (maxmtu);
+}
+
+#if INET6
+static inline unsigned int
+tcp_maxmtu6(struct rtentry *rt)
+{
+ unsigned int maxmtu;
+
+ RT_LOCK_ASSERT_HELD(rt);
+ lck_rw_lock_shared(nd_if_rwlock);
+ 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));
+ lck_rw_done(nd_if_rwlock);
+
+ return (maxmtu);
+}
+#endif
+
/*
* Determine a reasonable value for maxseg size.
* If the route is known, check route for mtu.
* 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)
+tcp_mss(tp, offer, input_ifscope)
struct tcpcb *tp;
int offer;
-#if INET6
- int isipv6;
-#endif
+ unsigned int input_ifscope;
{
register struct rtentry *rt;
struct ifnet *ifp;
register int rtt, mss;
- u_long bufsize;
+ 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 lgminh = isipv6 ? sizeof (struct tcpip6hdr) :
- sizeof (struct tcpiphdr);
-#else /* INET6 */
-#define lgminh (sizeof (struct tcpiphdr))
-#endif /* INET6 */
+ int isipv6;
+ int min_protoh;
+#endif
inp = tp->t_inpcb;
#if INET6
- if (isipv6)
- rt = tcp_rtlookup6(inp);
+ 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);
+ if (rt != NULL &&
+ (IN6_IS_ADDR_LOOPBACK(&inp->in6p_faddr) ||
+ IN6_IS_ADDR_LINKLOCAL(&inp->in6p_faddr) ||
+ rt->rt_gateway->sa_family == AF_LINK ||
+ in6_localaddr(&inp->in6p_faddr))) {
+ tp->t_flags |= TF_LOCAL;
+ }
+ }
else
#endif /* INET6 */
- rt = tcp_rtlookup(inp);
+ {
+ rt = tcp_rtlookup(inp, input_ifscope);
+ if (rt != NULL &&
+ (rt->rt_gateway->sa_family == AF_LINK ||
+ rt->rt_ifp->if_flags & IFF_LOOPBACK ||
+ in_localaddr(inp->inp_faddr))) {
+ tp->t_flags |= TF_LOCAL;
+ }
+ }
+ isnetlocal = (tp->t_flags & TF_LOCAL);
+
if (rt == NULL) {
tp->t_maxopd = tp->t_maxseg =
#if INET6
return;
}
ifp = rt->rt_ifp;
+ /*
+ * 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 (ifp->if_type == IFT_PPP && slowlink_wsize > 0 &&
+ ifp->if_baudrate > 9600 && ifp->if_baudrate <= 128000) {
+ tp->t_flags |= TF_SLOWLINK;
+ }
so = inp->inp_socket;
taop = rmx_taop(rt->rt_rmx);
isipv6 ? tcp_v6mssdflt :
#endif /* INET6 */
tcp_mssdflt;
- else
+ else {
+ /*
+ * Prevent DoS attack with too small MSS. Round up
+ * to at least minmss.
+ */
+ offer = max(offer, tcp_minmss);
/*
* Sanity check: make sure that maxopd will be large
* enough to allow some data on segments even is the
* funny things may happen in tcp_output.
*/
offer = max(offer, 64);
+ }
taop->tao_mssopt = offer;
/*
* 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));
+ tp->t_rttmin = rtt / (RTM_RTTUNIT / TCP_RETRANSHZ);
+ else
+ tp->t_rttmin = isnetlocal ? tcp_TCPTV_MIN : TCPTV_REXMTMIN;
+ tp->t_srtt = rtt / (RTM_RTTUNIT / (TCP_RETRANSHZ * 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));
+ (RTM_RTTUNIT / (TCP_RETRANSHZ * TCP_RTTVAR_SCALE));
tcpstat.tcps_usedrttvar++;
} else {
/* default variation is +- 1 rtt */
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);
+ ((tp->t_srtt >> 2) + tp->t_rttvar) >> 1,
+ tp->t_rttmin, TCPTV_REXMTMAX,
+ TCP_ADD_REXMTSLOP(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 =
+ tp->t_rttmin = isnetlocal ? tcp_TCPTV_MIN : TCPTV_REXMTMIN;
+
#if INET6
- isipv6 ? nd_ifinfo[rt->rt_ifp->if_index].linkmtu :
+ mss = (isipv6 ? tcp_maxmtu6(rt) : tcp_maxmtu(rt));
+#else
+ mss = tcp_maxmtu(rt);
#endif
- ifp->if_mtu - lgminh;
+ mss -= min_protoh;
if (rt->rt_rmx.rmx_mtu == 0) {
#if INET6
if (isipv6) {
- if (!in6_localaddr(&inp->in6p_faddr))
+ if (!isnetlocal)
mss = min(mss, tcp_v6mssdflt);
} else
#endif /* INET6 */
- if (!in_localaddr(inp->inp_faddr))
+ if (!isnetlocal)
mss = min(mss, tcp_mssdflt);
}
+
mss = min(mss, offer);
/*
* maxopd stores the maximum length of data AND options
tp->t_maxopd = mss;
/*
- * 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.
+ * 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 &&
+ 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;
+ tp->t_maxseg = mss;
-#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
+ * Calculate corrected value for sb_max; ensure to upgrade the
+ * numerator for large sb_max values else it will overflow.
+ */
+ sb_max_corrected = (sb_max * (u_int64_t)MCLBYTES) / (MSIZE + MCLBYTES);
+
+ /*
+ * 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
- if ((bufsize = rt->rt_rmx.rmx_sendpipe) == 0)
+ 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 = roundup(bufsize, mss);
- if (bufsize > sb_max)
- bufsize = sb_max;
+ 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_snd, bufsize);
}
tp->t_maxseg = mss;
#if RTV_RPIPE
- if ((bufsize = rt->rt_rmx.rmx_recvpipe) == 0)
+ bufsize = rt->rt_rmx.rmx_recvpipe;
+ if (bufsize < so->so_rcv.sb_hiwat)
#endif
bufsize = so->so_rcv.sb_hiwat;
if (bufsize > mss) {
- bufsize = roundup(bufsize, mss);
- if (bufsize > sb_max)
- bufsize = sb_max;
+ 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);
}
- /*
- * 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;
+
+ set_tcp_stream_priority(so);
if (rt->rt_rmx.rmx_ssthresh) {
/*
*/
tp->snd_ssthresh = max(2 * mss, rt->rt_rmx.rmx_ssthresh);
tcpstat.tcps_usedssthresh++;
+ } else {
+ tp->snd_ssthresh = TCP_MAXWIN << TCP_MAX_WINSHIFT;
}
+
+
+ /*
+ * Set the slow-start flight size depending on whether this
+ * is a local network or not.
+ */
+ if (CC_ALGO(tp)->cwnd_init != NULL)
+ CC_ALGO(tp)->cwnd_init(tp);
+
+ DTRACE_TCP5(cc, void, NULL, struct inpcb *, tp->t_inpcb, struct tcpcb *, tp,
+ struct tcphdr *, NULL, int32_t, 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(tp, isipv6)
+tcp_mssopt(tp)
struct tcpcb *tp;
-#if INET6
- int isipv6;
-#endif
{
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 */
+ int isipv6;
+ int min_protoh;
+#endif
+
+#if INET6
+ 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 INET6
if (isipv6)
- rt = tcp_rtlookup6(tp->t_inpcb);
+ rt = tcp_rtlookup6(tp->t_inpcb, IFSCOPE_NONE);
else
#endif /* INET6 */
- rt = tcp_rtlookup(tp->t_inpcb);
- if (rt == NULL)
- return
+ rt = tcp_rtlookup(tp->t_inpcb, IFSCOPE_NONE);
+ if (rt == NULL) {
+ return (
#if INET6
isipv6 ? tcp_v6mssdflt :
#endif /* INET6 */
- tcp_mssdflt;
+ tcp_mssdflt);
+ }
+ /*
+ * 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 (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
+ /* Route locked during lookup above */
+ RT_UNLOCK(rt);
+ 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_newreno_partial_ack(tp, th)
+ struct tcpcb *tp;
+ struct tcphdr *th;
+{
+ tcp_seq onxt = tp->snd_nxt;
+ u_int32_t ocwnd = tp->snd_cwnd;
+ tp->t_timer[TCPT_REXMT] = 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 + (th->th_ack - tp->snd_una);
+ 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 > th->th_ack - tp->snd_una)
+ tp->snd_cwnd -= th->th_ack - tp->snd_una;
+ else
+ tp->snd_cwnd = 0;
+ tp->snd_cwnd += tp->t_maxseg;
+
+}
+
+/*
+ * 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 int rnd;
+ static struct timeval old_runtime;
+ static unsigned int cur_cnt, old_cnt;
+ struct timeval tv;
+ struct inpcb *inp = NULL;
+ struct tcpcb *tp;
+
+ if ((head->so_options & SO_ACCEPTCONN) == 0)
+ return 0;
+
+ so = TAILQ_FIRST(&head->so_incomp);
+ if (!so)
+ return 0;
+
+ microtime(&tv);
+ if ((i = (tv.tv_sec - old_runtime.tv_sec)) != 0) {
+ old_runtime = tv;
+ old_cnt = cur_cnt / i;
+ cur_cnt = 0;
+ }
+
+
+ qlen = head->so_incqlen;
+ 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);
+ }
+ /* Find a connection that is not already closing (or being served) */
+ while (so) {
+ inp = (struct inpcb *)so->so_pcb;
+
+ sonext = TAILQ_NEXT(so, so_list);
+
+ 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 (lck_mtx_try_lock(&inp->inpcb_mtx)) {
+ so->so_usecount++;
+ if ((so->so_usecount == 2) &&
+ (so->so_state & SS_INCOMP) != 0 &&
+ (so->so_flags & SOF_INCOMP_INPROGRESS) == 0)
+ break;
+ else {/* don't use if being accepted or used in any other way */
+ in_pcb_checkstate(inp, WNT_RELEASE, 1);
+ tcp_unlock(so, 1, 0);
+ }
+ }
+ 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)
+ return 0;
+
+ /* Makes sure socket is still in the right state to be discarded */
+
+ if (in_pcb_checkstate(inp, WNT_RELEASE, 1) == WNT_STOPUSING) {
+ tcp_unlock(so, 1, 0);
+ return 0;
+ }
+
+ if (so->so_usecount != 2 || !(so->so_state & SS_INCOMP)) {
+ /* do not discard: that socket is being accepted */
+ tcp_unlock(so, 1, 0);
+ return 0;
+ }
+
+ TAILQ_REMOVE(&head->so_incomp, so, so_list);
+ tcp_unlock(head, 0, 0);
+
+ lck_mtx_assert(&inp->inpcb_mtx, LCK_MTX_ASSERT_OWNED);
+ tp = sototcpcb(so);
+ so->so_flags |= SOF_OVERFLOW;
+ so->so_head = NULL;
+
+ tcp_close(tp);
+ tp->t_unacksegs = 0;
+
+ if (inp->inp_wantcnt > 0 && inp->inp_wantcnt != WNT_STOPUSING) {
+ /* 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
+ */
+ so->so_usecount--;
+
+ tcp_unlock(so, 1, 0);
+ } else {
+ /* Unlock this socket and leave the reference on. We need to
+ * acquire the pcbinfo lock in order to fully dispose it off
+ */
+ tcp_unlock(so, 0, 0);
+
+ lck_rw_lock_exclusive(tcbinfo.mtx);
+
+ tcp_lock(so, 0, 0);
+
+ /* Release the reference held for so_incomp queue */
+ 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
+ */
+ tcp_unlock(so, 1, 0);
+ } else {
+
+ /* Drop the reference held for this function */
+ so->so_usecount--;
+
+ in_pcbdispose(inp);
+ }
+ lck_rw_done(tcbinfo.mtx);
+ }
+ tcpstat.tcps_drops++;
+
+ tcp_lock(head, 0, 0);
+ head->so_incqlen--;
+ head->so_qlen--;
+ 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)
+{
+ tcp_set_new_cc(so, TCP_CC_ALGO_NEWRENO_INDEX);
+}
+
+static void
+tcp_set_new_cc(struct socket *so, uint16_t cc_index)
+{
+ struct inpcb *inp = sotoinpcb(so);
+ struct tcpcb *tp = intotcpcb(inp);
+ uint16_t 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;
+
+ /* Decide if the connection is just starting or if
+ * we have sent some packets on it.
+ */
+ if (tp->snd_nxt > tp->iss) {
+ /* Already sent some packets */
+ if (CC_ALGO(tp)->switch_to != NULL)
+ CC_ALGO(tp)->switch_to(tp, old_cc_index);
+ } else {
+ if (CC_ALGO(tp)->init != NULL)
+ CC_ALGO(tp)->init(tp);
+ }
+ DTRACE_TCP5(cc, void, NULL, struct inpcb *, inp,
+ struct tcpcb *, tp, struct tcphdr *, NULL,
+ int32_t, TCP_CC_CHANGE_ALGO);
+ }
+}
+
+static int
+tcp_getstat SYSCTL_HANDLER_ARGS
+{
+#pragma unused(oidp, arg1, arg2)
+
+ int error;
- mss = rt->rt_ifp->if_mtu - lgminh;
+ if (req->oldptr == 0) {
+ req->oldlen= (size_t)sizeof(struct tcpstat);
+ }
+
+ error = SYSCTL_OUT(req, &tcpstat, MIN(sizeof (tcpstat), req->oldlen));
+
+ return (error);
+
+}
+
+SYSCTL_PROC(_net_inet_tcp, TCPCTL_STATS, stats, 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)
- return mss;
+ int error, val = tcprexmtthresh;
+
+ 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
+ */
+
+ 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