/*
- * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2017 Apple Inc. All rights reserved.
*
- * @APPLE_LICENSE_HEADER_START@
- *
- * The contents of this file constitute Original Code as defined in and
- * are subject to the Apple Public Source License Version 1.1 (the
- * "License"). You may not use this file except in compliance with the
- * License. Please obtain a copy of the License at
- * http://www.apple.com/publicsource and read it before using this file.
- *
- * This Original Code and all software distributed under the License are
- * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
+ *
+ * This file contains Original Code and/or Modifications of Original Code
+ * as defined in and that are subject to the Apple Public Source License
+ * Version 2.0 (the 'License'). You may not use this file except in
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
+ *
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
+ *
+ * The Original Code and all software distributed under the License are
+ * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
- * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
- * License for the specific language governing rights and limitations
- * under the License.
- *
- * @APPLE_LICENSE_HEADER_END@
+ * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
+ * limitations under the License.
+ *
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
/*
* Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
* SUCH DAMAGE.
*
* @(#)tcp_timer.c 8.2 (Berkeley) 5/24/95
+ * $FreeBSD: src/sys/netinet/tcp_timer.c,v 1.34.2.11 2001/08/22 00:59:12 silby Exp $
*/
-#if ISFB31
-#include "opt_compat.h"
-#include "opt_tcpdebug.h"
-#endif
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/kernel.h>
+#include <sys/mbuf.h>
#include <sys/sysctl.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/protosw.h>
-
+#include <sys/domain.h>
+#include <sys/mcache.h>
+#include <sys/queue.h>
+#include <kern/locks.h>
#include <kern/cpu_number.h> /* before tcp_seq.h, for tcp_random18() */
+#include <mach/boolean.h>
#include <net/route.h>
+#include <net/if_var.h>
+#include <net/ntstat.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
-#include <netinet/ip.h>
-#include <netinet/ip6.h>
#include <netinet/in_pcb.h>
+#if INET6
+#include <netinet6/in6_pcb.h>
+#endif
#include <netinet/ip_var.h>
#include <netinet/tcp.h>
+#include <netinet/tcp_cache.h>
#include <netinet/tcp_fsm.h>
#include <netinet/tcp_seq.h>
#include <netinet/tcp_timer.h>
#include <netinet/tcp_var.h>
+#include <netinet/tcp_cc.h>
+#if INET6
+#include <netinet6/tcp6_var.h>
+#endif
#include <netinet/tcpip.h>
#if TCPDEBUG
#include <netinet/tcp_debug.h>
#endif
#include <sys/kdebug.h>
+#include <mach/sdt.h>
+#include <netinet/mptcp_var.h>
+
+/* Max number of times a stretch ack can be delayed on a connection */
+#define TCP_STRETCHACK_DELAY_THRESHOLD 5
+
+/*
+ * If the host processor has been sleeping for too long, this is the threshold
+ * used to avoid sending stale retransmissions.
+ */
+#define TCP_SLEEP_TOO_LONG (10 * 60 * 1000) /* 10 minutes in ms */
+
+/* tcp timer list */
+struct tcptimerlist tcp_timer_list;
+
+/* List of pcbs in timewait state, protected by tcbinfo's ipi_lock */
+struct tcptailq tcp_tw_tailq;
-#define DBG_FNC_TCP_FAST NETDBG_CODE(DBG_NETTCP, (5 << 8))
-#define DBG_FNC_TCP_SLOW NETDBG_CODE(DBG_NETTCP, (5 << 8) | 1)
+static int
+sysctl_msec_to_ticks SYSCTL_HANDLER_ARGS
+{
+#pragma unused(arg1, arg2)
+ int error, s, tt;
+
+ tt = *(int *)oidp->oid_arg1;
+ s = tt * 1000 / TCP_RETRANSHZ;;
+
+ error = sysctl_handle_int(oidp, &s, 0, req);
+ if (error || !req->newptr)
+ return (error);
+
+ tt = s * TCP_RETRANSHZ / 1000;
+ if (tt < 1)
+ return (EINVAL);
+
+ *(int *)oidp->oid_arg1 = tt;
+ return (0);
+}
+
+int tcp_keepinit;
+SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINIT, keepinit,
+ CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
+ &tcp_keepinit, 0, sysctl_msec_to_ticks, "I", "");
+
+int tcp_keepidle;
+SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPIDLE, keepidle,
+ CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
+ &tcp_keepidle, 0, sysctl_msec_to_ticks, "I", "");
+int tcp_keepintvl;
+SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINTVL, keepintvl,
+ CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
+ &tcp_keepintvl, 0, sysctl_msec_to_ticks, "I", "");
-int tcp_keepinit = TCPTV_KEEP_INIT;
-SYSCTL_INT(_net_inet_tcp, TCPCTL_KEEPINIT, keepinit,
- CTLFLAG_RW, &tcp_keepinit , 0, "");
+int tcp_keepcnt;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, keepcnt,
+ CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
+ &tcp_keepcnt, 0, "number of times to repeat keepalive");
-int tcp_keepidle = TCPTV_KEEP_IDLE;
-SYSCTL_INT(_net_inet_tcp, TCPCTL_KEEPIDLE, keepidle,
- CTLFLAG_RW, &tcp_keepidle , 0, "");
+int tcp_msl;
+SYSCTL_PROC(_net_inet_tcp, OID_AUTO, msl,
+ CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
+ &tcp_msl, 0, sysctl_msec_to_ticks, "I", "Maximum segment lifetime");
-static int tcp_keepintvl = TCPTV_KEEPINTVL;
-SYSCTL_INT(_net_inet_tcp, TCPCTL_KEEPINTVL, keepintvl,
- CTLFLAG_RW, &tcp_keepintvl , 0, "");
+/*
+ * Avoid DoS via TCP Robustness in Persist Condition
+ * (see http://www.ietf.org/id/draft-ananth-tcpm-persist-02.txt)
+ * by allowing a system wide maximum persistence timeout value when in
+ * Zero Window Probe mode.
+ *
+ * Expressed in milliseconds to be consistent without timeout related
+ * values, the TCP socket option is in seconds.
+ */
+u_int32_t tcp_max_persist_timeout = 0;
+SYSCTL_PROC(_net_inet_tcp, OID_AUTO, max_persist_timeout,
+ CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
+ &tcp_max_persist_timeout, 0, sysctl_msec_to_ticks, "I",
+ "Maximum persistence timeout for ZWP");
static int always_keepalive = 0;
SYSCTL_INT(_net_inet_tcp, OID_AUTO, always_keepalive,
- CTLFLAG_RW, &always_keepalive , 0, "");
+ CTLFLAG_RW | CTLFLAG_LOCKED,
+ &always_keepalive , 0, "Assume SO_KEEPALIVE on all TCP connections");
-static int tcp_keepcnt = TCPTV_KEEPCNT;
- /* max idle probes */
-static int tcp_maxpersistidle = TCPTV_KEEP_IDLE;
- /* max idle time in persist */
-int tcp_maxidle;
+/*
+ * This parameter determines how long the timer list will stay in fast or
+ * quick mode even though all connections are idle. In this state, the
+ * timer will run more frequently anticipating new data.
+ */
+int timer_fastmode_idlemax = TCP_FASTMODE_IDLERUN_MAX;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, timer_fastmode_idlemax,
+ CTLFLAG_RW | CTLFLAG_LOCKED,
+ &timer_fastmode_idlemax, 0, "Maximum idle generations in fast mode");
+/*
+ * See tcp_syn_backoff[] for interval values between SYN retransmits;
+ * the value set below defines the number of retransmits, before we
+ * disable the timestamp and window scaling options during subsequent
+ * SYN retransmits. Setting it to 0 disables the dropping off of those
+ * two options.
+ */
+static int tcp_broken_peer_syn_rxmit_thres = 10;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, broken_peer_syn_rexmit_thres,
+ CTLFLAG_RW | CTLFLAG_LOCKED, &tcp_broken_peer_syn_rxmit_thres, 0,
+ "Number of retransmitted SYNs before disabling RFC 1323 "
+ "options on local connections");
+static int tcp_timer_advanced = 0;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcp_timer_advanced,
+ CTLFLAG_RD | CTLFLAG_LOCKED, &tcp_timer_advanced, 0,
+ "Number of times one of the timers was advanced");
-struct inpcbhead time_wait_slots[N_TIME_WAIT_SLOTS];
-int cur_tw_slot = 0;
+static int tcp_resched_timerlist = 0;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, tcp_resched_timerlist,
+ CTLFLAG_RD | CTLFLAG_LOCKED, &tcp_resched_timerlist, 0,
+ "Number of times timer list was rescheduled as part of processing a packet");
-u_long *delack_bitmask;
-u_long current_active_connections = 0;
-u_long last_active_conn_count = 0;
+int tcp_pmtud_black_hole_detect = 1 ;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, pmtud_blackhole_detection,
+ CTLFLAG_RW | CTLFLAG_LOCKED, &tcp_pmtud_black_hole_detect, 0,
+ "Path MTU Discovery Black Hole Detection");
+int tcp_pmtud_black_hole_mss = 1200 ;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, pmtud_blackhole_mss,
+ CTLFLAG_RW | CTLFLAG_LOCKED, &tcp_pmtud_black_hole_mss, 0,
+ "Path MTU Discovery Black Hole Detection lowered MSS");
-void add_to_time_wait(tp)
- struct tcpcb *tp;
-{
- int tw_slot;
+static u_int32_t tcp_mss_rec_medium = 1200;
+static u_int32_t tcp_mss_rec_low = 512;
- LIST_REMOVE(tp->t_inpcb, inp_list);
+#define TCP_REPORT_STATS_INTERVAL 43200 /* 12 hours, in seconds */
+int tcp_report_stats_interval = TCP_REPORT_STATS_INTERVAL;
- if (tp->t_timer[TCPT_2MSL] == 0)
- tp->t_timer[TCPT_2MSL] = 1;
+/* performed garbage collection of "used" sockets */
+static boolean_t tcp_gc_done = FALSE;
- tp->t_idle += tp->t_timer[TCPT_2MSL] & (N_TIME_WAIT_SLOTS - 1);
- tw_slot = (tp->t_timer[TCPT_2MSL] & (N_TIME_WAIT_SLOTS - 1)) + cur_tw_slot;
- if (tw_slot >= N_TIME_WAIT_SLOTS)
- tw_slot -= N_TIME_WAIT_SLOTS;
+/* max idle probes */
+int tcp_maxpersistidle;
- LIST_INSERT_HEAD(&time_wait_slots[tw_slot], tp->t_inpcb, inp_list);
-}
+/*
+ * TCP delack timer is set to 100 ms. Since the processing of timer list
+ * in fast mode will happen no faster than 100 ms, the delayed ack timer
+ * will fire some where between 100 and 200 ms.
+ */
+int tcp_delack = TCP_RETRANSHZ / 10;
+#if MPTCP
+/*
+ * MP_JOIN retransmission of 3rd ACK will be every 500 msecs without backoff
+ */
+int tcp_jack_rxmt = TCP_RETRANSHZ / 2;
+#endif /* MPTCP */
+static boolean_t tcp_itimer_done = FALSE;
+static void tcp_remove_timer(struct tcpcb *tp);
+static void tcp_sched_timerlist(uint32_t offset);
+static u_int32_t tcp_run_conn_timer(struct tcpcb *tp, u_int16_t *mode,
+ u_int16_t probe_if_index);
+static void tcp_sched_timers(struct tcpcb *tp);
+static inline void tcp_set_lotimer_index(struct tcpcb *);
+__private_extern__ void tcp_remove_from_time_wait(struct inpcb *inp);
+static inline void tcp_update_mss_core(struct tcpcb *tp, struct ifnet *ifp);
+__private_extern__ void tcp_report_stats(void);
+static u_int64_t tcp_last_report_time;
/*
- * Fast timeout routine for processing delayed acks
+ * Structure to store previously reported stats so that we can send
+ * incremental changes in each report interval.
*/
-void
-tcp_fasttimo()
-{
- register struct inpcb *inp;
- register struct tcpcb *tp;
+struct tcp_last_report_stats {
+ u_int32_t tcps_connattempt;
+ u_int32_t tcps_accepts;
+ u_int32_t tcps_ecn_client_setup;
+ u_int32_t tcps_ecn_server_setup;
+ u_int32_t tcps_ecn_client_success;
+ u_int32_t tcps_ecn_server_success;
+ u_int32_t tcps_ecn_not_supported;
+ u_int32_t tcps_ecn_lost_syn;
+ u_int32_t tcps_ecn_lost_synack;
+ u_int32_t tcps_ecn_recv_ce;
+ u_int32_t tcps_ecn_recv_ece;
+ u_int32_t tcps_ecn_sent_ece;
+ u_int32_t tcps_ecn_conn_recv_ce;
+ u_int32_t tcps_ecn_conn_recv_ece;
+ u_int32_t tcps_ecn_conn_plnoce;
+ u_int32_t tcps_ecn_conn_pl_ce;
+ u_int32_t tcps_ecn_conn_nopl_ce;
+ u_int32_t tcps_ecn_fallback_synloss;
+ u_int32_t tcps_ecn_fallback_reorder;
+ u_int32_t tcps_ecn_fallback_ce;
+ /* TFO-related statistics */
+ u_int32_t tcps_tfo_syn_data_rcv;
+ u_int32_t tcps_tfo_cookie_req_rcv;
+ u_int32_t tcps_tfo_cookie_sent;
+ u_int32_t tcps_tfo_cookie_invalid;
+ u_int32_t tcps_tfo_cookie_req;
+ u_int32_t tcps_tfo_cookie_rcv;
+ u_int32_t tcps_tfo_syn_data_sent;
+ u_int32_t tcps_tfo_syn_data_acked;
+ u_int32_t tcps_tfo_syn_loss;
+ u_int32_t tcps_tfo_blackhole;
+ u_int32_t tcps_tfo_cookie_wrong;
+ u_int32_t tcps_tfo_no_cookie_rcv;
+ u_int32_t tcps_tfo_heuristics_disable;
+ u_int32_t tcps_tfo_sndblackhole;
+};
- register u_long i,j;
- register u_long temp_mask;
- register u_long elem_base = 0;
- struct inpcbhead *head;
- int s = splnet();
- static
- int delack_checked = 0;
+/* Returns true if the timer is on the timer list */
+#define TIMER_IS_ON_LIST(tp) ((tp)->t_flags & TF_TIMER_ONLIST)
- KERNEL_DEBUG(DBG_FNC_TCP_FAST | DBG_FUNC_START, 0,0,0,0,0);
+/* Run the TCP timerlist atleast once every hour */
+#define TCP_TIMERLIST_MAX_OFFSET (60 * 60 * TCP_RETRANSHZ)
- if (!tcp_delack_enabled)
- return;
- if ((current_active_connections > DELACK_BITMASK_THRESH) &&
- (last_active_conn_count > DELACK_BITMASK_THRESH)) {
- for (i=0; i < (tcbinfo.hashsize / 32); i++) {
- if (delack_bitmask[i]) {
- temp_mask = 1;
- for (j=0; j < 32; j++) {
- if (temp_mask & delack_bitmask[i]) {
- head = &tcbinfo.hashbase[elem_base + j];
- for (inp=head->lh_first; inp != 0; inp = inp->inp_hash.le_next) {
- delack_checked++;
- if ((tp = (struct tcpcb *)inp->inp_ppcb) && (tp->t_flags & TF_DELACK)) {
- tp->t_flags &= ~TF_DELACK;
- tp->t_flags |= TF_ACKNOW;
- tcpstat.tcps_delack++;
- (void) tcp_output(tp);
- }
+static void add_to_time_wait_locked(struct tcpcb *tp, uint32_t delay);
+static boolean_t tcp_garbage_collect(struct inpcb *, int);
+
+#define TIMERENTRY_TO_TP(te) ((struct tcpcb *)((uintptr_t)te - offsetof(struct tcpcb, tentry.le.le_next)))
+
+#define VERIFY_NEXT_LINK(elm,field) do { \
+ if (LIST_NEXT((elm),field) != NULL && \
+ LIST_NEXT((elm),field)->field.le_prev != \
+ &((elm)->field.le_next)) \
+ panic("Bad link elm %p next->prev != elm", (elm)); \
+} while(0)
+
+#define VERIFY_PREV_LINK(elm,field) do { \
+ if (*(elm)->field.le_prev != (elm)) \
+ panic("Bad link elm %p prev->next != elm", (elm)); \
+} while(0)
+
+#define TCP_SET_TIMER_MODE(mode, i) do { \
+ if (IS_TIMER_HZ_10MS(i)) \
+ (mode) |= TCP_TIMERLIST_10MS_MODE; \
+ else if (IS_TIMER_HZ_100MS(i)) \
+ (mode) |= TCP_TIMERLIST_100MS_MODE; \
+ else \
+ (mode) |= TCP_TIMERLIST_500MS_MODE; \
+} while(0)
+
+#if (DEVELOPMENT || DEBUG)
+SYSCTL_UINT(_net_inet_tcp, OID_AUTO, mss_rec_medium,
+ CTLFLAG_RW | CTLFLAG_LOCKED, &tcp_mss_rec_medium, 0,
+ "Medium MSS based on recommendation in link status report");
+SYSCTL_UINT(_net_inet_tcp, OID_AUTO, mss_rec_low,
+ CTLFLAG_RW | CTLFLAG_LOCKED, &tcp_mss_rec_low, 0,
+ "Low MSS based on recommendation in link status report");
+
+static int32_t tcp_change_mss_recommended = 0;
+static int
+sysctl_change_mss_recommended SYSCTL_HANDLER_ARGS
+{
+#pragma unused(oidp, arg1, arg2)
+ int i, err = 0, changed = 0;
+ struct ifnet *ifp;
+ struct if_link_status ifsr;
+ struct if_cellular_status_v1 *new_cell_sr;
+ err = sysctl_io_number(req, tcp_change_mss_recommended,
+ sizeof (int32_t), &i, &changed);
+ if (changed) {
+ ifnet_head_lock_shared();
+ TAILQ_FOREACH(ifp, &ifnet_head, if_link) {
+ if (IFNET_IS_CELLULAR(ifp)) {
+ bzero(&ifsr, sizeof (ifsr));
+ new_cell_sr = &ifsr.ifsr_u.ifsr_cell.if_cell_u.if_status_v1;
+ ifsr.ifsr_version = IF_CELLULAR_STATUS_REPORT_CURRENT_VERSION;
+ ifsr.ifsr_len = sizeof(*new_cell_sr);
+
+ /* Set MSS recommended */
+ new_cell_sr->valid_bitmask |= IF_CELL_UL_MSS_RECOMMENDED_VALID;
+ new_cell_sr->mss_recommended = i;
+ err = ifnet_link_status_report(ifp, new_cell_sr, sizeof (new_cell_sr));
+ if (err == 0) {
+ tcp_change_mss_recommended = i;
+ } else {
+ break;
+ }
}
- }
- temp_mask <<= 1;
- }
- delack_bitmask[i] = 0;
- }
- elem_base += 32;
- }
- }
- else
- {
- for (inp = tcb.lh_first; inp != NULL; inp = inp->inp_list.le_next) {
- if ((tp = (struct tcpcb *)inp->inp_ppcb) &&
- (tp->t_flags & TF_DELACK)) {
- tp->t_flags &= ~TF_DELACK;
- tp->t_flags |= TF_ACKNOW;
- tcpstat.tcps_delack++;
- (void) tcp_output(tp);
- }
+ }
+ ifnet_head_done();
}
- }
+ return (err);
+}
- last_active_conn_count = current_active_connections;
- KERNEL_DEBUG(DBG_FNC_TCP_FAST | DBG_FUNC_END, delack_checked,tcpstat.tcps_delack,0,0,0);
- splx(s);
+SYSCTL_PROC(_net_inet_tcp, OID_AUTO, change_mss_recommended,
+ CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED, &tcp_change_mss_recommended,
+ 0, sysctl_change_mss_recommended, "IU", "Change MSS recommended");
-}
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, report_stats_interval,
+ CTLFLAG_RW | CTLFLAG_LOCKED, &tcp_report_stats_interval, 0,
+ "Report stats interval");
+#endif /* (DEVELOPMENT || DEBUG) */
+
+/*
+ * Macro to compare two timers. If there is a reset of the sign bit,
+ * it is safe to assume that the timer has wrapped around. By doing
+ * signed comparision, we take care of wrap around such that the value
+ * with the sign bit reset is actually ahead of the other.
+ */
+inline int32_t
+timer_diff(uint32_t t1, uint32_t toff1, uint32_t t2, uint32_t toff2) {
+ return (int32_t)((t1 + toff1) - (t2 + toff2));
+};
/*
- * Tcp protocol timeout routine called every 500 ms.
- * Updates the timers in all active tcb's and
- * causes finite state machine actions if timers expire.
+ * Add to tcp timewait list, delay is given in milliseconds.
*/
+static void
+add_to_time_wait_locked(struct tcpcb *tp, uint32_t delay)
+{
+ struct inpcbinfo *pcbinfo = &tcbinfo;
+ struct inpcb *inp = tp->t_inpcb;
+ uint32_t timer;
+
+ /* pcb list should be locked when we get here */
+ lck_rw_assert(pcbinfo->ipi_lock, LCK_RW_ASSERT_EXCLUSIVE);
+
+ /* We may get here multiple times, so check */
+ if (!(inp->inp_flags2 & INP2_TIMEWAIT)) {
+ pcbinfo->ipi_twcount++;
+ inp->inp_flags2 |= INP2_TIMEWAIT;
+
+ /* Remove from global inp list */
+ LIST_REMOVE(inp, inp_list);
+ } else {
+ TAILQ_REMOVE(&tcp_tw_tailq, tp, t_twentry);
+ }
+
+ /* Compute the time at which this socket can be closed */
+ timer = tcp_now + delay;
+
+ /* We will use the TCPT_2MSL timer for tracking this delay */
+
+ if (TIMER_IS_ON_LIST(tp))
+ tcp_remove_timer(tp);
+ tp->t_timer[TCPT_2MSL] = timer;
+
+ TAILQ_INSERT_TAIL(&tcp_tw_tailq, tp, t_twentry);
+}
+
void
-tcp_slowtimo()
+add_to_time_wait(struct tcpcb *tp, uint32_t delay)
{
- register struct inpcb *ip, *ipnxt;
- register struct tcpcb *tp;
- register int i;
- int s;
-#if TCPDEBUG
- int ostate;
-#endif
-#if KDEBUG
- static int tws_checked;
-#endif
+ struct inpcbinfo *pcbinfo = &tcbinfo;
+ if (tp->t_inpcb->inp_socket->so_options & SO_NOWAKEFROMSLEEP)
+ socket_post_kev_msg_closed(tp->t_inpcb->inp_socket);
+
+ /* 19182803: Notify nstat that connection is closing before waiting. */
+ nstat_pcb_detach(tp->t_inpcb);
- KERNEL_DEBUG(DBG_FNC_TCP_SLOW | DBG_FUNC_START, 0,0,0,0,0);
- s = splnet();
+ if (!lck_rw_try_lock_exclusive(pcbinfo->ipi_lock)) {
+ tcp_unlock(tp->t_inpcb->inp_socket, 0, 0);
+ lck_rw_lock_exclusive(pcbinfo->ipi_lock);
+ tcp_lock(tp->t_inpcb->inp_socket, 0, 0);
+ }
+ add_to_time_wait_locked(tp, delay);
+ lck_rw_done(pcbinfo->ipi_lock);
- tcp_maxidle = tcp_keepcnt * tcp_keepintvl;
+ inpcb_gc_sched(pcbinfo, INPCB_TIMER_LAZY);
+}
- ip = tcb.lh_first;
- if (ip == NULL) {
- splx(s);
- return;
+/* If this is on time wait queue, remove it. */
+void
+tcp_remove_from_time_wait(struct inpcb *inp)
+{
+ struct tcpcb *tp = intotcpcb(inp);
+ if (inp->inp_flags2 & INP2_TIMEWAIT)
+ TAILQ_REMOVE(&tcp_tw_tailq, tp, t_twentry);
+}
+
+static boolean_t
+tcp_garbage_collect(struct inpcb *inp, int istimewait)
+{
+ boolean_t active = FALSE;
+ struct socket *so;
+ struct tcpcb *tp;
+
+ so = inp->inp_socket;
+ tp = intotcpcb(inp);
+
+ /*
+ * Skip if still in use or busy; it would have been more efficient
+ * if we were to test so_usecount against 0, but this isn't possible
+ * due to the current implementation of tcp_dropdropablreq() where
+ * overflow sockets that are eligible for garbage collection have
+ * their usecounts set to 1.
+ */
+ if (!lck_mtx_try_lock_spin(&inp->inpcb_mtx))
+ return (TRUE);
+
+ /* Check again under the lock */
+ if (so->so_usecount > 1) {
+ if (inp->inp_wantcnt == WNT_STOPUSING)
+ active = TRUE;
+ lck_mtx_unlock(&inp->inpcb_mtx);
+ return (active);
+ }
+
+ if (istimewait &&
+ TSTMP_GEQ(tcp_now, tp->t_timer[TCPT_2MSL]) &&
+ tp->t_state != TCPS_CLOSED) {
+ /* Become a regular mutex */
+ lck_mtx_convert_spin(&inp->inpcb_mtx);
+ tcp_close(tp);
}
+
/*
- * Search through tcb's and update active timers.
+ * Overflowed socket dropped from the listening queue? Do this
+ * only if we are called to clean up the time wait slots, since
+ * tcp_dropdropablreq() considers a socket to have been fully
+ * dropped after add_to_time_wait() is finished.
+ * Also handle the case of connections getting closed by the peer
+ * while in the queue as seen with rdar://6422317
+ *
*/
- for (; ip != NULL; ip = ipnxt) {
- ipnxt = ip->inp_list.le_next;
- tp = intotcpcb(ip);
- if (tp == 0 || tp->t_state == TCPS_LISTEN)
- continue;
- for (i = 0; i < TCPT_NTIMERS; i++) {
- if (tp->t_timer[i] && --tp->t_timer[i] == 0) {
-#if TCPDEBUG
- ostate = tp->t_state;
-#endif
- tp = tcp_timers(tp, i);
- if (tp == NULL)
- goto tpgone;
-#if TCPDEBUG
- if (tp->t_inpcb->inp_socket->so_options
- & SO_DEBUG)
- tcp_trace(TA_USER, ostate, tp,
- (void *)0,
- (struct tcphdr *)0,
- PRU_SLOWTIMO);
-#endif
- }
+ if (so->so_usecount == 1 &&
+ ((istimewait && (so->so_flags & SOF_OVERFLOW)) ||
+ ((tp != NULL) && (tp->t_state == TCPS_CLOSED) &&
+ (so->so_head != NULL) &&
+ ((so->so_state & (SS_INCOMP|SS_CANTSENDMORE|SS_CANTRCVMORE)) ==
+ (SS_INCOMP|SS_CANTSENDMORE|SS_CANTRCVMORE))))) {
+
+ if (inp->inp_state != INPCB_STATE_DEAD) {
+ /* Become a regular mutex */
+ lck_mtx_convert_spin(&inp->inpcb_mtx);
+#if INET6
+ if (SOCK_CHECK_DOM(so, PF_INET6))
+ in6_pcbdetach(inp);
+ else
+#endif /* INET6 */
+ in_pcbdetach(inp);
+ }
+ VERIFY(so->so_usecount > 0);
+ so->so_usecount--;
+ if (inp->inp_wantcnt == WNT_STOPUSING)
+ active = TRUE;
+ lck_mtx_unlock(&inp->inpcb_mtx);
+ return (active);
+ } else if (inp->inp_wantcnt != WNT_STOPUSING) {
+ lck_mtx_unlock(&inp->inpcb_mtx);
+ return (FALSE);
+ }
+
+ /*
+ * We get here because the PCB is no longer searchable
+ * (WNT_STOPUSING); detach (if needed) and dispose if it is dead
+ * (usecount is 0). This covers all cases, including overflow
+ * sockets and those that are considered as "embryonic",
+ * i.e. created by sonewconn() in TCP input path, and have
+ * not yet been committed. For the former, we reduce the usecount
+ * to 0 as done by the code above. For the latter, the usecount
+ * would have reduced to 0 as part calling soabort() when the
+ * socket is dropped at the end of tcp_input().
+ */
+ if (so->so_usecount == 0) {
+ DTRACE_TCP4(state__change, void, NULL, struct inpcb *, inp,
+ struct tcpcb *, tp, int32_t, TCPS_CLOSED);
+ /* Become a regular mutex */
+ lck_mtx_convert_spin(&inp->inpcb_mtx);
+
+ /*
+ * If this tp still happens to be on the timer list,
+ * take it out
+ */
+ if (TIMER_IS_ON_LIST(tp)) {
+ tcp_remove_timer(tp);
+ }
+
+ if (inp->inp_state != INPCB_STATE_DEAD) {
+#if INET6
+ if (SOCK_CHECK_DOM(so, PF_INET6))
+ in6_pcbdetach(inp);
+ else
+#endif /* INET6 */
+ in_pcbdetach(inp);
}
- tp->t_idle++;
- tp->t_duration++;
- if (tp->t_rtt)
- tp->t_rtt++;
-tpgone:
- ;
+ in_pcbdispose(inp);
+ return (FALSE);
}
-#if KDEBUG
- tws_checked = 0;
+ lck_mtx_unlock(&inp->inpcb_mtx);
+ return (TRUE);
+}
+
+/*
+ * TCP garbage collector callback (inpcb_timer_func_t).
+ *
+ * Returns the number of pcbs that will need to be gc-ed soon,
+ * returnining > 0 will keep timer active.
+ */
+void
+tcp_gc(struct inpcbinfo *ipi)
+{
+ struct inpcb *inp, *nxt;
+ struct tcpcb *tw_tp, *tw_ntp;
+#if TCPDEBUG
+ int ostate;
#endif
- KERNEL_DEBUG(DBG_FNC_TCP_SLOW | DBG_FUNC_NONE, tws_checked,0,0,0,0);
+#if KDEBUG
+ static int tws_checked = 0;
+#endif
+
+ KERNEL_DEBUG(DBG_FNC_TCP_SLOW | DBG_FUNC_START, 0, 0, 0, 0, 0);
/*
- * Process the items in the current time-wait slot
+ * Update tcp_now here as it may get used while
+ * processing the slow timer.
*/
+ calculate_tcp_clock();
- for (ip = time_wait_slots[cur_tw_slot].lh_first; ip; ip = ipnxt)
- {
-#if KDEBUG
- tws_checked++;
-#endif
- ipnxt = ip->inp_list.le_next;
- tp = intotcpcb(ip);
- if (tp->t_timer[TCPT_2MSL] >= N_TIME_WAIT_SLOTS) {
- tp->t_timer[TCPT_2MSL] -= N_TIME_WAIT_SLOTS;
- tp->t_idle += N_TIME_WAIT_SLOTS;
+ /*
+ * Garbage collect socket/tcpcb: We need to acquire the list lock
+ * exclusively to do this
+ */
+
+ if (lck_rw_try_lock_exclusive(ipi->ipi_lock) == FALSE) {
+ /* don't sweat it this time; cleanup was done last time */
+ if (tcp_gc_done == TRUE) {
+ tcp_gc_done = FALSE;
+ KERNEL_DEBUG(DBG_FNC_TCP_SLOW | DBG_FUNC_END,
+ tws_checked, cur_tw_slot, 0, 0, 0);
+ /* Lock upgrade failed, give up this round */
+ atomic_add_32(&ipi->ipi_gc_req.intimer_fast, 1);
+ return;
}
- else
- tp->t_timer[TCPT_2MSL] = 0;
+ /* Upgrade failed, lost lock now take it again exclusive */
+ lck_rw_lock_exclusive(ipi->ipi_lock);
+ }
+ tcp_gc_done = TRUE;
+
+ LIST_FOREACH_SAFE(inp, &tcb, inp_list, nxt) {
+ if (tcp_garbage_collect(inp, 0))
+ atomic_add_32(&ipi->ipi_gc_req.intimer_fast, 1);
+ }
- if (tp->t_timer[TCPT_2MSL] == 0)
- tp = tcp_timers(tp, TCPT_2MSL);
+ /* Now cleanup the time wait ones */
+ TAILQ_FOREACH_SAFE(tw_tp, &tcp_tw_tailq, t_twentry, tw_ntp) {
+ /*
+ * We check the timestamp here without holding the
+ * socket lock for better performance. If there are
+ * any pcbs in time-wait, the timer will get rescheduled.
+ * Hence some error in this check can be tolerated.
+ *
+ * Sometimes a socket on time-wait queue can be closed if
+ * 2MSL timer expired but the application still has a
+ * usecount on it.
+ */
+ if (tw_tp->t_state == TCPS_CLOSED ||
+ TSTMP_GEQ(tcp_now, tw_tp->t_timer[TCPT_2MSL])) {
+ if (tcp_garbage_collect(tw_tp->t_inpcb, 1))
+ atomic_add_32(&ipi->ipi_gc_req.intimer_lazy, 1);
+ }
}
- if (++cur_tw_slot >= N_TIME_WAIT_SLOTS)
- cur_tw_slot = 0;
+ /* take into account pcbs that are still in time_wait_slots */
+ atomic_add_32(&ipi->ipi_gc_req.intimer_lazy, ipi->ipi_twcount);
-#if TCP_COMPAT_42
- tcp_iss += TCP_ISSINCR/PR_SLOWHZ; /* increment iss */
- if ((int)tcp_iss < 0)
- tcp_iss = TCP_ISSINCR; /* XXX */
-#endif
- tcp_now++; /* for timestamps */
- splx(s);
- KERNEL_DEBUG(DBG_FNC_TCP_SLOW | DBG_FUNC_END, tws_checked, cur_tw_slot,0,0,0);
+ lck_rw_done(ipi->ipi_lock);
+
+ /* Clean up the socache while we are here */
+ if (so_cache_timer())
+ atomic_add_32(&ipi->ipi_gc_req.intimer_lazy, 1);
+
+ KERNEL_DEBUG(DBG_FNC_TCP_SLOW | DBG_FUNC_END, tws_checked,
+ cur_tw_slot, 0, 0, 0);
+
+ return;
}
/*
* Cancel all timers for TCP tp.
*/
void
-tcp_canceltimers(tp)
- struct tcpcb *tp;
+tcp_canceltimers(struct tcpcb *tp)
{
- register int i;
+ int i;
+ tcp_remove_timer(tp);
for (i = 0; i < TCPT_NTIMERS; i++)
tp->t_timer[i] = 0;
+ tp->tentry.timer_start = tcp_now;
+ tp->tentry.index = TCPT_NONE;
}
+int tcp_syn_backoff[TCP_MAXRXTSHIFT + 1] =
+ { 1, 1, 1, 1, 1, 2, 4, 8, 16, 32, 64, 64, 64 };
+
int tcp_backoff[TCP_MAXRXTSHIFT + 1] =
{ 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 };
static int tcp_totbackoff = 511; /* sum of tcp_backoff[] */
+void
+tcp_rexmt_save_state(struct tcpcb *tp)
+{
+ u_int32_t fsize;
+ if (TSTMP_SUPPORTED(tp)) {
+ /*
+ * Since timestamps are supported on the connection,
+ * we can do recovery as described in rfc 4015.
+ */
+ fsize = tp->snd_max - tp->snd_una;
+ tp->snd_ssthresh_prev = max(fsize, tp->snd_ssthresh);
+ tp->snd_recover_prev = tp->snd_recover;
+ } else {
+ /*
+ * Timestamp option is not supported on this connection.
+ * Record ssthresh and cwnd so they can
+ * be recovered if this turns out to be a "bad" retransmit.
+ * A retransmit is considered "bad" if an ACK for this
+ * segment is received within RTT/2 interval; the assumption
+ * here is that the ACK was already in flight. See
+ * "On Estimating End-to-End Network Path Properties" by
+ * Allman and Paxson for more details.
+ */
+ tp->snd_cwnd_prev = tp->snd_cwnd;
+ tp->snd_ssthresh_prev = tp->snd_ssthresh;
+ tp->snd_recover_prev = tp->snd_recover;
+ if (IN_FASTRECOVERY(tp))
+ tp->t_flags |= TF_WASFRECOVERY;
+ else
+ tp->t_flags &= ~TF_WASFRECOVERY;
+ }
+ tp->t_srtt_prev = (tp->t_srtt >> TCP_RTT_SHIFT) + 2;
+ tp->t_rttvar_prev = (tp->t_rttvar >> TCP_RTTVAR_SHIFT);
+ tp->t_flagsext &= ~(TF_RECOMPUTE_RTT);
+}
+
+/*
+ * Revert to the older segment size if there is an indication that PMTU
+ * blackhole detection was not needed.
+ */
+void
+tcp_pmtud_revert_segment_size(struct tcpcb *tp)
+{
+ int32_t optlen;
+
+ VERIFY(tp->t_pmtud_saved_maxopd > 0);
+ tp->t_flags |= TF_PMTUD;
+ tp->t_flags &= ~TF_BLACKHOLE;
+ optlen = tp->t_maxopd - tp->t_maxseg;
+ tp->t_maxopd = tp->t_pmtud_saved_maxopd;
+ tp->t_maxseg = tp->t_maxopd - optlen;
+ /*
+ * Reset the slow-start flight size as it
+ * may depend on the new MSS
+ */
+ if (CC_ALGO(tp)->cwnd_init != NULL)
+ CC_ALGO(tp)->cwnd_init(tp);
+ tp->t_pmtud_start_ts = 0;
+ tcpstat.tcps_pmtudbh_reverted++;
+}
+
/*
* TCP timer processing.
*/
struct tcpcb *
-tcp_timers(tp, timer)
- register struct tcpcb *tp;
- int timer;
+tcp_timers(struct tcpcb *tp, int timer)
{
- register int rexmt;
- struct socket *so_tmp;
+ int32_t rexmt, optlen = 0, idle_time = 0;
+ struct socket *so;
+ struct tcptemp *t_template;
+#if TCPDEBUG
+ int ostate;
+#endif
+
#if INET6
int isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV4) == 0;
#endif /* INET6 */
+ u_int64_t accsleep_ms;
+ u_int32_t last_sleep_ms = 0;
+
+ so = tp->t_inpcb->inp_socket;
+ idle_time = tcp_now - tp->t_rcvtime;
switch (timer) {
/*
* 2 MSL timeout in shutdown went off. If we're closed but
* still waiting for peer to close and connection has been idle
- * too long, or if 2MSL time is up from TIME_WAIT, delete connection
- * control block. Otherwise, check again in a bit.
+ * too long, or if 2MSL time is up from TIME_WAIT or FIN_WAIT_2,
+ * delete connection control block.
+ * Otherwise, (this case shouldn't happen) check again in a bit
+ * we keep the socket in the main list in that case.
*/
case TCPT_2MSL:
+ tcp_free_sackholes(tp);
if (tp->t_state != TCPS_TIME_WAIT &&
- tp->t_idle <= tcp_maxidle) {
- tp->t_timer[TCPT_2MSL] = tcp_keepintvl;
- add_to_time_wait(tp);
- }
- else
+ tp->t_state != TCPS_FIN_WAIT_2 &&
+ ((idle_time > 0) && (idle_time < TCP_CONN_MAXIDLE(tp)))) {
+ tp->t_timer[TCPT_2MSL] = OFFSET_FROM_START(tp,
+ (u_int32_t)TCP_CONN_KEEPINTVL(tp));
+ } else {
tp = tcp_close(tp);
+ return(tp);
+ }
break;
/*
* to a longer retransmit interval and retransmit one segment.
*/
case TCPT_REXMT:
- if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) {
+ absolutetime_to_nanoseconds(mach_absolutetime_asleep,
+ &accsleep_ms);
+ accsleep_ms = accsleep_ms / 1000000UL;
+ if (accsleep_ms > tp->t_accsleep_ms)
+ last_sleep_ms = accsleep_ms - tp->t_accsleep_ms;
+ /*
+ * Drop a connection in the retransmit timer
+ * 1. If we have retransmitted more than TCP_MAXRXTSHIFT
+ * times
+ * 2. If the time spent in this retransmission episode is
+ * more than the time limit set with TCP_RXT_CONNDROPTIME
+ * socket option
+ * 3. If TCP_RXT_FINDROP socket option was set and
+ * we have already retransmitted the FIN 3 times without
+ * receiving an ack
+ */
+ if (++tp->t_rxtshift > TCP_MAXRXTSHIFT ||
+ (tp->t_rxt_conndroptime > 0 && tp->t_rxtstart > 0 &&
+ (tcp_now - tp->t_rxtstart) >= tp->t_rxt_conndroptime) ||
+ ((tp->t_flagsext & TF_RXTFINDROP) != 0 &&
+ (tp->t_flags & TF_SENTFIN) != 0 && tp->t_rxtshift >= 4) ||
+ (tp->t_rxtshift > 4 && last_sleep_ms >= TCP_SLEEP_TOO_LONG)) {
+ if ((tp->t_flagsext & TF_RXTFINDROP) != 0) {
+ tcpstat.tcps_rxtfindrop++;
+ } else if (last_sleep_ms >= TCP_SLEEP_TOO_LONG) {
+ tcpstat.tcps_drop_after_sleep++;
+ } else {
+ tcpstat.tcps_timeoutdrop++;
+ }
+ if (tp->t_rxtshift >= TCP_MAXRXTSHIFT) {
+ if (TCP_ECN_ENABLED(tp)) {
+ INP_INC_IFNET_STAT(tp->t_inpcb,
+ ecn_on.rxmit_drop);
+ } else {
+ INP_INC_IFNET_STAT(tp->t_inpcb,
+ ecn_off.rxmit_drop);
+ }
+ }
tp->t_rxtshift = TCP_MAXRXTSHIFT;
- tcpstat.tcps_timeoutdrop++;
- so_tmp = tp->t_inpcb->inp_socket;
+ postevent(so, 0, EV_TIMEOUT);
+ soevent(so,
+ (SO_FILT_HINT_LOCKED|SO_FILT_HINT_TIMEOUT));
+
+ if (TCP_ECN_ENABLED(tp) &&
+ tp->t_state == TCPS_ESTABLISHED)
+ tcp_heuristic_ecn_droprxmt(tp);
+
tp = tcp_drop(tp, tp->t_softerror ?
tp->t_softerror : ETIMEDOUT);
- postevent(so_tmp, 0, EV_TIMEOUT);
+
break;
}
+
tcpstat.tcps_rexmttimeo++;
- rexmt = TCP_REXMTVAL(tp) * tcp_backoff[tp->t_rxtshift];
- TCPT_RANGESET(tp->t_rxtcur, rexmt,
- tp->t_rttmin, TCPTV_REXMTMAX);
- tp->t_timer[TCPT_REXMT] = tp->t_rxtcur;
+ tp->t_accsleep_ms = accsleep_ms;
+
+ if (tp->t_rxtshift == 1 &&
+ tp->t_state == TCPS_ESTABLISHED) {
+ /* Set the time at which retransmission started. */
+ tp->t_rxtstart = tcp_now;
+
+ /*
+ * if this is the first retransmit timeout, save
+ * the state so that we can recover if the timeout
+ * is spurious.
+ */
+ tcp_rexmt_save_state(tp);
+ }
+#if MPTCP
+ if ((tp->t_rxtshift >= mptcp_fail_thresh) &&
+ (tp->t_state == TCPS_ESTABLISHED) &&
+ (tp->t_mpflags & TMPF_MPTCP_TRUE)) {
+ mptcp_act_on_txfail(so);
+
+ }
+#endif /* MPTCP */
+
+ if (tp->t_adaptive_wtimo > 0 &&
+ tp->t_rxtshift > tp->t_adaptive_wtimo &&
+ TCPS_HAVEESTABLISHED(tp->t_state)) {
+ /* Send an event to the application */
+ soevent(so,
+ (SO_FILT_HINT_LOCKED|
+ SO_FILT_HINT_ADAPTIVE_WTIMO));
+ }
+
+ /*
+ * If this is a retransmit timeout after PTO, the PTO
+ * was not effective
+ */
+ if (tp->t_flagsext & TF_SENT_TLPROBE) {
+ tp->t_flagsext &= ~(TF_SENT_TLPROBE);
+ tcpstat.tcps_rto_after_pto++;
+ }
+
+ if (tp->t_flagsext & TF_DELAY_RECOVERY) {
+ /*
+ * Retransmit timer fired before entering recovery
+ * on a connection with packet re-ordering. This
+ * suggests that the reordering metrics computed
+ * are not accurate.
+ */
+ tp->t_reorderwin = 0;
+ tp->t_timer[TCPT_DELAYFR] = 0;
+ tp->t_flagsext &= ~(TF_DELAY_RECOVERY);
+ }
+
+ if (tp->t_state == TCPS_SYN_RECEIVED)
+ tcp_disable_tfo(tp);
+
+ if ((tp->t_tfo_stats & TFO_S_SYN_DATA_SENT) &&
+ !(tp->t_tfo_flags & TFO_F_NO_SNDPROBING) &&
+ ((tp->t_state != TCPS_SYN_SENT && tp->t_rxtshift > 1) ||
+ tp->t_rxtshift > 2)) {
+ /*
+ * For regular retransmissions, a first one is being
+ * done for tail-loss probe.
+ * Thus, if rxtshift > 1, this means we have sent the segment
+ * a total of 3 times.
+ *
+ * If we are in SYN-SENT state, then there is no tail-loss
+ * probe thus we have to let rxtshift go up to 3.
+ */
+ tcp_heuristic_tfo_middlebox(tp);
+
+ so->so_error = ENODATA;
+ sorwakeup(so);
+ sowwakeup(so);
+
+ tp->t_tfo_stats |= TFO_S_SEND_BLACKHOLE;
+ tcpstat.tcps_tfo_sndblackhole++;
+ }
+
+ if (tp->t_state == TCPS_SYN_SENT) {
+ rexmt = TCP_REXMTVAL(tp) * tcp_syn_backoff[tp->t_rxtshift];
+ tp->t_stat.synrxtshift = tp->t_rxtshift;
+
+ /* When retransmitting, disable TFO */
+ if (tfo_enabled(tp) && !(so->so_flags & SOF1_DATA_AUTHENTICATED)) {
+ tp->t_flagsext &= ~TF_FASTOPEN;
+ tp->t_tfo_flags |= TFO_F_SYN_LOSS;
+ }
+ } else {
+ rexmt = TCP_REXMTVAL(tp) * tcp_backoff[tp->t_rxtshift];
+ }
+
+ TCPT_RANGESET(tp->t_rxtcur, rexmt, tp->t_rttmin, TCPTV_REXMTMAX,
+ TCP_ADD_REXMTSLOP(tp));
+ tp->t_timer[TCPT_REXMT] = OFFSET_FROM_START(tp, tp->t_rxtcur);
+
+ if (INP_WAIT_FOR_IF_FEEDBACK(tp->t_inpcb))
+ goto fc_output;
+
+ tcp_free_sackholes(tp);
+ /*
+ * Check for potential Path MTU Discovery Black Hole
+ */
+ if (tcp_pmtud_black_hole_detect &&
+ !(tp->t_flagsext & TF_NOBLACKHOLE_DETECTION) &&
+ (tp->t_state == TCPS_ESTABLISHED)) {
+ if ((tp->t_flags & TF_PMTUD) &&
+ ((tp->t_flags & TF_MAXSEGSNT)
+ || tp->t_pmtud_lastseg_size > tcp_pmtud_black_hole_mss) &&
+ tp->t_rxtshift == 2) {
+ /*
+ * Enter Path MTU Black-hole Detection mechanism:
+ * - Disable Path MTU Discovery (IP "DF" bit).
+ * - Reduce MTU to lower value than what we
+ * negotiated with the peer.
+ */
+ /* Disable Path MTU Discovery for now */
+ tp->t_flags &= ~TF_PMTUD;
+ /* Record that we may have found a black hole */
+ tp->t_flags |= TF_BLACKHOLE;
+ optlen = tp->t_maxopd - tp->t_maxseg;
+ /* Keep track of previous MSS */
+ tp->t_pmtud_saved_maxopd = tp->t_maxopd;
+ tp->t_pmtud_start_ts = tcp_now;
+ if (tp->t_pmtud_start_ts == 0)
+ tp->t_pmtud_start_ts++;
+ /* Reduce the MSS to intermediary value */
+ if (tp->t_maxopd > tcp_pmtud_black_hole_mss) {
+ tp->t_maxopd = tcp_pmtud_black_hole_mss;
+ } else {
+ tp->t_maxopd = /* use the default MSS */
+#if INET6
+ isipv6 ? tcp_v6mssdflt :
+#endif /* INET6 */
+ tcp_mssdflt;
+ }
+ tp->t_maxseg = tp->t_maxopd - optlen;
+
+ /*
+ * Reset the slow-start flight size
+ * as it may depend on the new MSS
+ */
+ if (CC_ALGO(tp)->cwnd_init != NULL)
+ CC_ALGO(tp)->cwnd_init(tp);
+ tp->snd_cwnd = tp->t_maxseg;
+ }
+ /*
+ * If further retransmissions are still
+ * unsuccessful with a lowered MTU, maybe this
+ * isn't a Black Hole and we restore the previous
+ * MSS and blackhole detection flags.
+ */
+ else {
+
+ if ((tp->t_flags & TF_BLACKHOLE) &&
+ (tp->t_rxtshift > 4)) {
+ tcp_pmtud_revert_segment_size(tp);
+ tp->snd_cwnd = tp->t_maxseg;
+ }
+ }
+ }
+
+
+ /*
+ * Disable rfc1323 and rfc1644 if we haven't got any
+ * response to our SYN (after we reach the threshold)
+ * to work-around some broken terminal servers (most of
+ * which have hopefully been retired) that have bad VJ
+ * header compression code which trashes TCP segments
+ * containing unknown-to-them TCP options.
+ * Do this only on non-local connections.
+ */
+ if (tp->t_state == TCPS_SYN_SENT &&
+ tp->t_rxtshift == tcp_broken_peer_syn_rxmit_thres)
+ tp->t_flags &= ~(TF_REQ_SCALE|TF_REQ_TSTMP|TF_REQ_CC);
+
/*
* If losing, let the lower level know and try for
* a better route. Also, if we backed off this far,
}
tp->snd_nxt = tp->snd_una;
/*
- * Force a segment to be sent.
+ * Note: We overload snd_recover to function also as the
+ * snd_last variable described in RFC 2582
*/
- tp->t_flags |= TF_ACKNOW;
+ tp->snd_recover = tp->snd_max;
/*
- * If timing a segment in this window, stop the timer.
+ * Force a segment to be sent.
*/
- tp->t_rtt = 0;
+ tp->t_flags |= TF_ACKNOW;
+
+ /* If timing a segment in this window, stop the timer */
+ tp->t_rtttime = 0;
+
+ if (!IN_FASTRECOVERY(tp) && tp->t_rxtshift == 1)
+ tcpstat.tcps_tailloss_rto++;
+
+
/*
- * Close the congestion window down to one segment
- * (we'll open it by one segment for each ack we get).
- * Since we probably have a window's worth of unacked
- * data accumulated, this "slow start" keeps us from
- * dumping all that data as back-to-back packets (which
- * might overwhelm an intermediate gateway).
- *
- * There are two phases to the opening: Initially we
- * open by one mss on each ack. This makes the window
- * size increase exponentially with time. If the
- * window is larger than the path can handle, this
- * exponential growth results in dropped packet(s)
- * almost immediately. To get more time between
- * drops but still "push" the network to take advantage
- * of improving conditions, we switch from exponential
- * to linear window opening at some threshhold size.
- * For a threshhold, we use half the current window
- * size, truncated to a multiple of the mss.
- *
- * (the minimum cwnd that will give us exponential
- * growth is 2 mss. We don't allow the threshhold
- * to go below this.)
+ * RFC 5681 says: when a TCP sender detects segment loss
+ * using retransmit timer and the given segment has already
+ * been retransmitted by way of the retransmission timer at
+ * least once, the value of ssthresh is held constant
*/
- {
- u_int win = min(tp->snd_wnd, tp->snd_cwnd) / 2 / tp->t_maxseg;
- if (win < 2)
- win = 2;
- tp->snd_cwnd = tp->t_maxseg;
- tp->snd_ssthresh = win * tp->t_maxseg;
- tp->t_dupacks = 0;
+ if (tp->t_rxtshift == 1 &&
+ CC_ALGO(tp)->after_timeout != NULL) {
+ CC_ALGO(tp)->after_timeout(tp);
+ /*
+ * CWR notifications are to be sent on new data
+ * right after Fast Retransmits and ECE
+ * notification receipts.
+ */
+ if (TCP_ECN_ENABLED(tp))
+ tp->ecn_flags |= TE_SENDCWR;
}
+
+ EXIT_FASTRECOVERY(tp);
+
+ /* Exit cwnd non validated phase */
+ tp->t_flagsext &= ~TF_CWND_NONVALIDATED;
+
+
+fc_output:
+ tcp_ccdbg_trace(tp, NULL, TCP_CC_REXMT_TIMEOUT);
+
(void) tcp_output(tp);
break;
* backoff, drop the connection if the idle time
* (no responses to probes) reaches the maximum
* backoff that we would use if retransmitting.
+ *
+ * Drop the connection if we reached the maximum allowed time for
+ * Zero Window Probes without a non-zero update from the peer.
+ * See rdar://5805356
*/
- if (tp->t_rxtshift == TCP_MAXRXTSHIFT &&
- (tp->t_idle >= tcp_maxpersistidle ||
- tp->t_idle >= TCP_REXMTVAL(tp) * tcp_totbackoff)) {
+ if ((tp->t_rxtshift == TCP_MAXRXTSHIFT &&
+ (idle_time >= tcp_maxpersistidle ||
+ idle_time >= TCP_REXMTVAL(tp) * tcp_totbackoff)) ||
+ ((tp->t_persist_stop != 0) &&
+ TSTMP_LEQ(tp->t_persist_stop, tcp_now))) {
tcpstat.tcps_persistdrop++;
- so_tmp = tp->t_inpcb->inp_socket;
+ postevent(so, 0, EV_TIMEOUT);
+ soevent(so,
+ (SO_FILT_HINT_LOCKED|SO_FILT_HINT_TIMEOUT));
tp = tcp_drop(tp, ETIMEDOUT);
- postevent(so_tmp, 0, EV_TIMEOUT);
break;
}
tcp_setpersist(tp);
- tp->t_force = 1;
+ tp->t_flagsext |= TF_FORCE;
(void) tcp_output(tp);
- tp->t_force = 0;
+ tp->t_flagsext &= ~TF_FORCE;
break;
/*
*/
case TCPT_KEEP:
tcpstat.tcps_keeptimeo++;
+#if MPTCP
+ /*
+ * Regular TCP connections do not send keepalives after closing
+ * MPTCP must not also, after sending Data FINs.
+ */
+ struct mptcb *mp_tp = tp->t_mptcb;
+ if ((tp->t_mpflags & TMPF_MPTCP_TRUE) &&
+ (tp->t_state > TCPS_ESTABLISHED)) {
+ goto dropit;
+ } else if (mp_tp != NULL) {
+ if ((mptcp_ok_to_keepalive(mp_tp) == 0))
+ goto dropit;
+ }
+#endif /* MPTCP */
if (tp->t_state < TCPS_ESTABLISHED)
goto dropit;
if ((always_keepalive ||
- tp->t_inpcb->inp_socket->so_options & SO_KEEPALIVE) &&
- tp->t_state <= TCPS_CLOSING) {
- if (tp->t_idle >= tcp_keepidle + tcp_maxidle)
+ (tp->t_inpcb->inp_socket->so_options & SO_KEEPALIVE) ||
+ (tp->t_flagsext & TF_DETECT_READSTALL) ||
+ (tp->t_tfo_probe_state == TFO_PROBE_PROBING)) &&
+ (tp->t_state <= TCPS_CLOSING || tp->t_state == TCPS_FIN_WAIT_2)) {
+ if (idle_time >= TCP_CONN_KEEPIDLE(tp) + TCP_CONN_MAXIDLE(tp))
goto dropit;
/*
* Send a packet designed to force a response
* correspondent TCP to respond.
*/
tcpstat.tcps_keepprobe++;
-#if TCP_COMPAT_42
+ t_template = tcp_maketemplate(tp);
+ if (t_template) {
+ struct inpcb *inp = tp->t_inpcb;
+ struct tcp_respond_args tra;
+
+ bzero(&tra, sizeof(tra));
+ tra.nocell = INP_NO_CELLULAR(inp);
+ tra.noexpensive = INP_NO_EXPENSIVE(inp);
+ tra.awdl_unrestricted = INP_AWDL_UNRESTRICTED(inp);
+ tra.intcoproc_allowed = INP_INTCOPROC_ALLOWED(inp);
+ if (tp->t_inpcb->inp_flags & INP_BOUND_IF)
+ tra.ifscope = tp->t_inpcb->inp_boundifp->if_index;
+ else
+ tra.ifscope = IFSCOPE_NONE;
+ tcp_respond(tp, t_template->tt_ipgen,
+ &t_template->tt_t, (struct mbuf *)NULL,
+ tp->rcv_nxt, tp->snd_una - 1, 0, &tra);
+ (void) m_free(dtom(t_template));
+ if (tp->t_flagsext & TF_DETECT_READSTALL)
+ tp->t_rtimo_probes++;
+ }
+ tp->t_timer[TCPT_KEEP] = OFFSET_FROM_START(tp,
+ TCP_CONN_KEEPINTVL(tp));
+ } else {
+ tp->t_timer[TCPT_KEEP] = OFFSET_FROM_START(tp,
+ TCP_CONN_KEEPIDLE(tp));
+ }
+ if (tp->t_flagsext & TF_DETECT_READSTALL) {
+ struct ifnet *outifp = tp->t_inpcb->inp_last_outifp;
+ bool reenable_probe = false;
/*
- * The keepalive packet must have nonzero length
- * to get a 4.2 host to respond.
+ * The keep alive packets sent to detect a read
+ * stall did not get a response from the
+ * peer. Generate more keep-alives to confirm this.
+ * If the number of probes sent reaches the limit,
+ * generate an event.
*/
-#if INET6
- if (isipv6)
- tcp_respond(tp, (void *)&tp->t_template->tt_i6,
- &tp->t_template->tt_t,
- (struct mbuf *)NULL,
- tp->rcv_nxt - 1, tp->snd_una - 1,
- 0, isipv6);
- else
-#endif /* INET6 */
- tcp_respond(tp, (void *)&tp->t_template->tt_i,
- &tp->t_template->tt_t, (struct mbuf *)NULL,
- tp->rcv_nxt - 1, tp->snd_una - 1, 0,
- isipv6);
-#else
-#if INET6
- if (isipv6)
- tcp_respond(tp, (void *)&tp->t_template->tt_i6,
- &tp->t_template->tt_t,
- (struct mbuf *)NULL, tp->rcv_nxt,
- tp->snd_una - 1, 0, isipv6);
- else
-#endif /* INET6 */
- tcp_respond(tp, (void *)&tp->t_template->tt_i,
- &tp->t_template->tt_t, (struct mbuf *)NULL,
- tp->rcv_nxt, tp->snd_una - 1, 0, isipv6);
-#endif
- tp->t_timer[TCPT_KEEP] = tcp_keepintvl;
- } else
- tp->t_timer[TCPT_KEEP] = tcp_keepidle;
+ if (tp->t_adaptive_rtimo > 0) {
+ if (tp->t_rtimo_probes > tp->t_adaptive_rtimo) {
+ /* Generate an event */
+ soevent(so,
+ (SO_FILT_HINT_LOCKED |
+ SO_FILT_HINT_ADAPTIVE_RTIMO));
+ tcp_keepalive_reset(tp);
+ } else {
+ reenable_probe = true;
+ }
+ } else if (outifp != NULL &&
+ (outifp->if_eflags & IFEF_PROBE_CONNECTIVITY) &&
+ tp->t_rtimo_probes <= TCP_CONNECTIVITY_PROBES_MAX) {
+ reenable_probe = true;
+ } else {
+ tp->t_flagsext &= ~TF_DETECT_READSTALL;
+ }
+ if (reenable_probe) {
+ int ind = min(tp->t_rtimo_probes,
+ TCP_MAXRXTSHIFT);
+ tp->t_timer[TCPT_KEEP] = OFFSET_FROM_START(
+ tp, tcp_backoff[ind] * TCP_REXMTVAL(tp));
+ }
+ }
+ if (tp->t_tfo_probe_state == TFO_PROBE_PROBING) {
+ int ind;
+
+ tp->t_tfo_probes++;
+ ind = min(tp->t_tfo_probes, TCP_MAXRXTSHIFT);
+
+ /*
+ * We take the minimum among the time set by true
+ * keepalive (see above) and the backoff'd RTO. That
+ * way we backoff in case of packet-loss but will never
+ * timeout slower than regular keepalive due to the
+ * backing off.
+ */
+ tp->t_timer[TCPT_KEEP] = min(OFFSET_FROM_START(
+ tp, tcp_backoff[ind] * TCP_REXMTVAL(tp)),
+ tp->t_timer[TCPT_KEEP]);
+ } else if (tp->t_tfo_probe_state == TFO_PROBE_WAIT_DATA) {
+ /* Still no data! Let's assume a TFO-error and err out... */
+ tcp_heuristic_tfo_middlebox(tp);
+
+ so->so_error = ENODATA;
+ sorwakeup(so);
+ tp->t_tfo_stats |= TFO_S_RECV_BLACKHOLE;
+ tcpstat.tcps_tfo_blackhole++;
+ }
+ break;
+ case TCPT_DELACK:
+ if (tcp_delack_enabled && (tp->t_flags & TF_DELACK)) {
+ tp->t_flags &= ~TF_DELACK;
+ tp->t_timer[TCPT_DELACK] = 0;
+ tp->t_flags |= TF_ACKNOW;
+
+ /*
+ * If delayed ack timer fired while stretching
+ * acks, count the number of times the streaming
+ * detection was not correct. If this exceeds a
+ * threshold, disable strech ack on this
+ * connection
+ *
+ * Also, go back to acking every other packet.
+ */
+ if ((tp->t_flags & TF_STRETCHACK)) {
+ if (tp->t_unacksegs > 1 &&
+ tp->t_unacksegs < maxseg_unacked)
+ tp->t_stretchack_delayed++;
+
+ if (tp->t_stretchack_delayed >
+ TCP_STRETCHACK_DELAY_THRESHOLD) {
+ tp->t_flagsext |= TF_DISABLE_STRETCHACK;
+ /*
+ * Note the time at which stretch
+ * ack was disabled automatically
+ */
+ tp->rcv_nostrack_ts = tcp_now;
+ tcpstat.tcps_nostretchack++;
+ tp->t_stretchack_delayed = 0;
+ tp->rcv_nostrack_pkts = 0;
+ }
+ tcp_reset_stretch_ack(tp);
+ }
+
+ /*
+ * If we are measuring inter packet arrival jitter
+ * for throttling a connection, this delayed ack
+ * might be the reason for accumulating some
+ * jitter. So let's restart the measurement.
+ */
+ CLEAR_IAJ_STATE(tp);
+
+ tcpstat.tcps_delack++;
+ (void) tcp_output(tp);
+ }
+ break;
+
+#if MPTCP
+ case TCPT_JACK_RXMT:
+ if ((tp->t_state == TCPS_ESTABLISHED) &&
+ (tp->t_mpflags & TMPF_PREESTABLISHED) &&
+ (tp->t_mpflags & TMPF_JOINED_FLOW)) {
+ if (++tp->t_mprxtshift > TCP_MAXRXTSHIFT) {
+ tcpstat.tcps_timeoutdrop++;
+ postevent(so, 0, EV_TIMEOUT);
+ soevent(so,
+ (SO_FILT_HINT_LOCKED|
+ SO_FILT_HINT_TIMEOUT));
+ tp = tcp_drop(tp, tp->t_softerror ?
+ tp->t_softerror : ETIMEDOUT);
+ break;
+ }
+ tcpstat.tcps_join_rxmts++;
+ tp->t_flags |= TF_ACKNOW;
+
+ /*
+ * No backoff is implemented for simplicity for this
+ * corner case.
+ */
+ (void) tcp_output(tp);
+ }
+ break;
+#endif /* MPTCP */
+
+ case TCPT_PTO:
+ {
+ int32_t snd_len;
+ tp->t_flagsext &= ~(TF_SENT_TLPROBE);
+
+ /*
+ * Check if the connection is in the right state to
+ * send a probe
+ */
+ if (tp->t_state != TCPS_ESTABLISHED ||
+ (tp->t_rxtshift > 0 && !(tp->t_flagsext & TF_PROBING))
+ || tp->snd_max == tp->snd_una ||
+ !SACK_ENABLED(tp) || !TAILQ_EMPTY(&tp->snd_holes) ||
+ IN_FASTRECOVERY(tp))
+ break;
+
+ /*
+ * If there is no new data to send or if the
+ * connection is limited by receive window then
+ * retransmit the last segment, otherwise send
+ * new data.
+ */
+ snd_len = min(so->so_snd.sb_cc, tp->snd_wnd)
+ - (tp->snd_max - tp->snd_una);
+ if (snd_len > 0) {
+ tp->snd_nxt = tp->snd_max;
+ } else {
+ snd_len = min((tp->snd_max - tp->snd_una),
+ tp->t_maxseg);
+ tp->snd_nxt = tp->snd_max - snd_len;
+ }
+
+ tcpstat.tcps_pto++;
+ if (tp->t_flagsext & TF_PROBING)
+ tcpstat.tcps_probe_if++;
+
+ /* If timing a segment in this window, stop the timer */
+ tp->t_rtttime = 0;
+ /* Note that tail loss probe is being sent */
+ tp->t_flagsext |= TF_SENT_TLPROBE;
+ tp->t_tlpstart = tcp_now;
+
+ tp->snd_cwnd += tp->t_maxseg;
+ (void )tcp_output(tp);
+ tp->snd_cwnd -= tp->t_maxseg;
+
+ tp->t_tlphighrxt = tp->snd_nxt;
+ break;
+ }
+ case TCPT_DELAYFR:
+ tp->t_flagsext &= ~TF_DELAY_RECOVERY;
+
+ /*
+ * Don't do anything if one of the following is true:
+ * - the connection is already in recovery
+ * - sequence until snd_recover has been acknowledged.
+ * - retransmit timeout has fired
+ */
+ if (IN_FASTRECOVERY(tp) ||
+ SEQ_GEQ(tp->snd_una, tp->snd_recover) ||
+ tp->t_rxtshift > 0)
+ break;
+
+ VERIFY(SACK_ENABLED(tp));
+ tcp_rexmt_save_state(tp);
+ if (CC_ALGO(tp)->pre_fr != NULL) {
+ CC_ALGO(tp)->pre_fr(tp);
+ if (TCP_ECN_ENABLED(tp))
+ tp->ecn_flags |= TE_SENDCWR;
+ }
+ ENTER_FASTRECOVERY(tp);
+
+ tp->t_timer[TCPT_REXMT] = 0;
+ tcpstat.tcps_sack_recovery_episode++;
+ tp->t_sack_recovery_episode++;
+ tp->sack_newdata = tp->snd_nxt;
+ tp->snd_cwnd = tp->t_maxseg;
+ tcp_ccdbg_trace(tp, NULL, TCP_CC_ENTER_FASTRECOVERY);
+ (void) tcp_output(tp);
break;
dropit:
tcpstat.tcps_keepdrops++;
- so_tmp = tp->t_inpcb->inp_socket;
+ postevent(so, 0, EV_TIMEOUT);
+ soevent(so,
+ (SO_FILT_HINT_LOCKED|SO_FILT_HINT_TIMEOUT));
tp = tcp_drop(tp, ETIMEDOUT);
- postevent(so_tmp, 0, EV_TIMEOUT);
break;
}
+#if TCPDEBUG
+ if (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)
+ tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0,
+ PRU_SLOWTIMO);
+#endif
return (tp);
}
+
+/* Remove a timer entry from timer list */
+void
+tcp_remove_timer(struct tcpcb *tp)
+{
+ struct tcptimerlist *listp = &tcp_timer_list;
+
+ lck_mtx_assert(&tp->t_inpcb->inpcb_mtx, LCK_MTX_ASSERT_OWNED);
+ if (!(TIMER_IS_ON_LIST(tp))) {
+ return;
+ }
+ lck_mtx_lock(listp->mtx);
+
+ /* Check if pcb is on timer list again after acquiring the lock */
+ if (!(TIMER_IS_ON_LIST(tp))) {
+ lck_mtx_unlock(listp->mtx);
+ return;
+ }
+
+ if (listp->next_te != NULL && listp->next_te == &tp->tentry)
+ listp->next_te = LIST_NEXT(&tp->tentry, le);
+
+ LIST_REMOVE(&tp->tentry, le);
+ tp->t_flags &= ~(TF_TIMER_ONLIST);
+
+ listp->entries--;
+
+ tp->tentry.le.le_next = NULL;
+ tp->tentry.le.le_prev = NULL;
+ lck_mtx_unlock(listp->mtx);
+}
+
+/*
+ * Function to check if the timerlist needs to be rescheduled to run
+ * the timer entry correctly. Basically, this is to check if we can avoid
+ * taking the list lock.
+ */
+
+static boolean_t
+need_to_resched_timerlist(u_int32_t runtime, u_int16_t mode)
+{
+ struct tcptimerlist *listp = &tcp_timer_list;
+ int32_t diff;
+
+ /*
+ * If the list is being processed then the state of the list is
+ * in flux. In this case always acquire the lock and set the state
+ * correctly.
+ */
+ if (listp->running)
+ return (TRUE);
+
+ if (!listp->scheduled)
+ return (TRUE);
+
+ diff = timer_diff(listp->runtime, 0, runtime, 0);
+ if (diff <= 0) {
+ /* The list is going to run before this timer */
+ return (FALSE);
+ } else {
+ if (mode & TCP_TIMERLIST_10MS_MODE) {
+ if (diff <= TCP_TIMER_10MS_QUANTUM)
+ return (FALSE);
+ } else if (mode & TCP_TIMERLIST_100MS_MODE) {
+ if (diff <= TCP_TIMER_100MS_QUANTUM)
+ return (FALSE);
+ } else {
+ if (diff <= TCP_TIMER_500MS_QUANTUM)
+ return (FALSE);
+ }
+ }
+ return (TRUE);
+}
+
+void
+tcp_sched_timerlist(uint32_t offset)
+{
+ uint64_t deadline = 0;
+ struct tcptimerlist *listp = &tcp_timer_list;
+
+ lck_mtx_assert(listp->mtx, LCK_MTX_ASSERT_OWNED);
+
+ offset = min(offset, TCP_TIMERLIST_MAX_OFFSET);
+ listp->runtime = tcp_now + offset;
+ if (listp->runtime == 0) {
+ listp->runtime++;
+ offset++;
+ }
+
+ clock_interval_to_deadline(offset, USEC_PER_SEC, &deadline);
+
+ thread_call_enter_delayed(listp->call, deadline);
+ listp->scheduled = TRUE;
+}
+
+/*
+ * Function to run the timers for a connection.
+ *
+ * Returns the offset of next timer to be run for this connection which
+ * can be used to reschedule the timerlist.
+ *
+ * te_mode is an out parameter that indicates the modes of active
+ * timers for this connection.
+ */
+u_int32_t
+tcp_run_conn_timer(struct tcpcb *tp, u_int16_t *te_mode,
+ u_int16_t probe_if_index)
+{
+ struct socket *so;
+ u_int16_t i = 0, index = TCPT_NONE, lo_index = TCPT_NONE;
+ u_int32_t timer_val, offset = 0, lo_timer = 0;
+ int32_t diff;
+ boolean_t needtorun[TCPT_NTIMERS];
+ int count = 0;
+
+ VERIFY(tp != NULL);
+ bzero(needtorun, sizeof(needtorun));
+ *te_mode = 0;
+
+ tcp_lock(tp->t_inpcb->inp_socket, 1, 0);
+
+ so = tp->t_inpcb->inp_socket;
+ /* Release the want count on inp */
+ if (in_pcb_checkstate(tp->t_inpcb, WNT_RELEASE, 1)
+ == WNT_STOPUSING) {
+ if (TIMER_IS_ON_LIST(tp)) {
+ tcp_remove_timer(tp);
+ }
+
+ /* Looks like the TCP connection got closed while we
+ * were waiting for the lock.. Done
+ */
+ goto done;
+ }
+
+ /*
+ * If this connection is over an interface that needs to
+ * be probed, send probe packets to reinitiate communication.
+ */
+ if (probe_if_index > 0 && tp->t_inpcb->inp_last_outifp != NULL &&
+ tp->t_inpcb->inp_last_outifp->if_index == probe_if_index) {
+ tp->t_flagsext |= TF_PROBING;
+ tcp_timers(tp, TCPT_PTO);
+ tp->t_timer[TCPT_PTO] = 0;
+ tp->t_flagsext &= ~TF_PROBING;
+ }
+
+ /*
+ * Since the timer thread needs to wait for tcp lock, it may race
+ * with another thread that can cancel or reschedule the timer
+ * that is about to run. Check if we need to run anything.
+ */
+ if ((index = tp->tentry.index) == TCPT_NONE)
+ goto done;
+
+ timer_val = tp->t_timer[index];
+
+ diff = timer_diff(tp->tentry.runtime, 0, tcp_now, 0);
+ if (diff > 0) {
+ if (tp->tentry.index != TCPT_NONE) {
+ offset = diff;
+ *(te_mode) = tp->tentry.mode;
+ }
+ goto done;
+ }
+
+ tp->t_timer[index] = 0;
+ if (timer_val > 0) {
+ tp = tcp_timers(tp, index);
+ if (tp == NULL)
+ goto done;
+ }
+
+ /*
+ * Check if there are any other timers that need to be run.
+ * While doing it, adjust the timer values wrt tcp_now.
+ */
+ tp->tentry.mode = 0;
+ for (i = 0; i < TCPT_NTIMERS; ++i) {
+ if (tp->t_timer[i] != 0) {
+ diff = timer_diff(tp->tentry.timer_start,
+ tp->t_timer[i], tcp_now, 0);
+ if (diff <= 0) {
+ needtorun[i] = TRUE;
+ count++;
+ } else {
+ tp->t_timer[i] = diff;
+ needtorun[i] = FALSE;
+ if (lo_timer == 0 || diff < lo_timer) {
+ lo_timer = diff;
+ lo_index = i;
+ }
+ TCP_SET_TIMER_MODE(tp->tentry.mode, i);
+ }
+ }
+ }
+
+ tp->tentry.timer_start = tcp_now;
+ tp->tentry.index = lo_index;
+ VERIFY(tp->tentry.index == TCPT_NONE || tp->tentry.mode > 0);
+
+ if (tp->tentry.index != TCPT_NONE) {
+ tp->tentry.runtime = tp->tentry.timer_start +
+ tp->t_timer[tp->tentry.index];
+ if (tp->tentry.runtime == 0)
+ tp->tentry.runtime++;
+ }
+
+ if (count > 0) {
+ /* run any other timers outstanding at this time. */
+ for (i = 0; i < TCPT_NTIMERS; ++i) {
+ if (needtorun[i]) {
+ tp->t_timer[i] = 0;
+ tp = tcp_timers(tp, i);
+ if (tp == NULL) {
+ offset = 0;
+ *(te_mode) = 0;
+ goto done;
+ }
+ }
+ }
+ tcp_set_lotimer_index(tp);
+ }
+
+ if (tp->tentry.index < TCPT_NONE) {
+ offset = tp->t_timer[tp->tentry.index];
+ *(te_mode) = tp->tentry.mode;
+ }
+
+done:
+ if (tp != NULL && tp->tentry.index == TCPT_NONE) {
+ tcp_remove_timer(tp);
+ offset = 0;
+ }
+
+ tcp_unlock(so, 1, 0);
+ return(offset);
+}
+
+void
+tcp_run_timerlist(void * arg1, void * arg2)
+{
+#pragma unused(arg1, arg2)
+ struct tcptimerentry *te, *next_te;
+ struct tcptimerlist *listp = &tcp_timer_list;
+ struct tcpcb *tp;
+ uint32_t next_timer = 0; /* offset of the next timer on the list */
+ u_int16_t te_mode = 0; /* modes of all active timers in a tcpcb */
+ u_int16_t list_mode = 0; /* cumulative of modes of all tcpcbs */
+ uint32_t active_count = 0;
+
+ calculate_tcp_clock();
+
+ lck_mtx_lock(listp->mtx);
+
+ listp->running = TRUE;
+
+ LIST_FOREACH_SAFE(te, &listp->lhead, le, next_te) {
+ uint32_t offset = 0;
+ uint32_t runtime = te->runtime;
+ if (te->index < TCPT_NONE && TSTMP_GT(runtime, tcp_now)) {
+ offset = timer_diff(runtime, 0, tcp_now, 0);
+ if (next_timer == 0 || offset < next_timer) {
+ next_timer = offset;
+ }
+ list_mode |= te->mode;
+ continue;
+ }
+
+ tp = TIMERENTRY_TO_TP(te);
+
+ /*
+ * Acquire an inp wantcnt on the inpcb so that the socket
+ * won't get detached even if tcp_close is called
+ */
+ if (in_pcb_checkstate(tp->t_inpcb, WNT_ACQUIRE, 0)
+ == WNT_STOPUSING) {
+ /*
+ * Some how this pcb went into dead state while
+ * on the timer list, just take it off the list.
+ * Since the timer list entry pointers are
+ * protected by the timer list lock, we can
+ * do it here without the socket lock.
+ */
+ if (TIMER_IS_ON_LIST(tp)) {
+ tp->t_flags &= ~(TF_TIMER_ONLIST);
+ LIST_REMOVE(&tp->tentry, le);
+ listp->entries--;
+
+ tp->tentry.le.le_next = NULL;
+ tp->tentry.le.le_prev = NULL;
+ }
+ continue;
+ }
+ active_count++;
+
+ /*
+ * Store the next timerentry pointer before releasing the
+ * list lock. If that entry has to be removed when we
+ * release the lock, this pointer will be updated to the
+ * element after that.
+ */
+ listp->next_te = next_te;
+
+ VERIFY_NEXT_LINK(&tp->tentry, le);
+ VERIFY_PREV_LINK(&tp->tentry, le);
+
+ lck_mtx_unlock(listp->mtx);
+
+ offset = tcp_run_conn_timer(tp, &te_mode,
+ listp->probe_if_index);
+
+ lck_mtx_lock(listp->mtx);
+
+ next_te = listp->next_te;
+ listp->next_te = NULL;
+
+ if (offset > 0 && te_mode != 0) {
+ list_mode |= te_mode;
+
+ if (next_timer == 0 || offset < next_timer)
+ next_timer = offset;
+ }
+ }
+
+ if (!LIST_EMPTY(&listp->lhead)) {
+ u_int16_t next_mode = 0;
+ if ((list_mode & TCP_TIMERLIST_10MS_MODE) ||
+ (listp->pref_mode & TCP_TIMERLIST_10MS_MODE))
+ next_mode = TCP_TIMERLIST_10MS_MODE;
+ else if ((list_mode & TCP_TIMERLIST_100MS_MODE) ||
+ (listp->pref_mode & TCP_TIMERLIST_100MS_MODE))
+ next_mode = TCP_TIMERLIST_100MS_MODE;
+ else
+ next_mode = TCP_TIMERLIST_500MS_MODE;
+
+ if (next_mode != TCP_TIMERLIST_500MS_MODE) {
+ listp->idleruns = 0;
+ } else {
+ /*
+ * the next required mode is slow mode, but if
+ * the last one was a faster mode and we did not
+ * have enough idle runs, repeat the last mode.
+ *
+ * We try to keep the timer list in fast mode for
+ * some idle time in expectation of new data.
+ */
+ if (listp->mode != next_mode &&
+ listp->idleruns < timer_fastmode_idlemax) {
+ listp->idleruns++;
+ next_mode = listp->mode;
+ next_timer = TCP_TIMER_100MS_QUANTUM;
+ } else {
+ listp->idleruns = 0;
+ }
+ }
+ listp->mode = next_mode;
+ if (listp->pref_offset != 0)
+ next_timer = min(listp->pref_offset, next_timer);
+
+ if (listp->mode == TCP_TIMERLIST_500MS_MODE)
+ next_timer = max(next_timer,
+ TCP_TIMER_500MS_QUANTUM);
+
+ tcp_sched_timerlist(next_timer);
+ } else {
+ /*
+ * No need to reschedule this timer, but always run
+ * periodically at a much higher granularity.
+ */
+ tcp_sched_timerlist(TCP_TIMERLIST_MAX_OFFSET);
+ }
+
+ listp->running = FALSE;
+ listp->pref_mode = 0;
+ listp->pref_offset = 0;
+ listp->probe_if_index = 0;
+
+ lck_mtx_unlock(listp->mtx);
+}
+
+/*
+ * Function to check if the timerlist needs to be rescheduled to run this
+ * connection's timers correctly.
+ */
+void
+tcp_sched_timers(struct tcpcb *tp)
+{
+ struct tcptimerentry *te = &tp->tentry;
+ u_int16_t index = te->index;
+ u_int16_t mode = te->mode;
+ struct tcptimerlist *listp = &tcp_timer_list;
+ int32_t offset = 0;
+ boolean_t list_locked = FALSE;
+
+ if (tp->t_inpcb->inp_state == INPCB_STATE_DEAD) {
+ /* Just return without adding the dead pcb to the list */
+ if (TIMER_IS_ON_LIST(tp)) {
+ tcp_remove_timer(tp);
+ }
+ return;
+ }
+
+ if (index == TCPT_NONE) {
+ /* Nothing to run */
+ tcp_remove_timer(tp);
+ return;
+ }
+
+ /*
+ * compute the offset at which the next timer for this connection
+ * has to run.
+ */
+ offset = timer_diff(te->runtime, 0, tcp_now, 0);
+ if (offset <= 0) {
+ offset = 1;
+ tcp_timer_advanced++;
+ }
+
+ if (!TIMER_IS_ON_LIST(tp)) {
+ if (!list_locked) {
+ lck_mtx_lock(listp->mtx);
+ list_locked = TRUE;
+ }
+
+ if (!TIMER_IS_ON_LIST(tp)) {
+ LIST_INSERT_HEAD(&listp->lhead, te, le);
+ tp->t_flags |= TF_TIMER_ONLIST;
+
+ listp->entries++;
+ if (listp->entries > listp->maxentries)
+ listp->maxentries = listp->entries;
+
+ /* if the list is not scheduled, just schedule it */
+ if (!listp->scheduled)
+ goto schedule;
+ }
+ }
+
+ /*
+ * Timer entry is currently on the list, check if the list needs
+ * to be rescheduled.
+ */
+ if (need_to_resched_timerlist(te->runtime, mode)) {
+ tcp_resched_timerlist++;
+
+ if (!list_locked) {
+ lck_mtx_lock(listp->mtx);
+ list_locked = TRUE;
+ }
+
+ VERIFY_NEXT_LINK(te, le);
+ VERIFY_PREV_LINK(te, le);
+
+ if (listp->running) {
+ listp->pref_mode |= mode;
+ if (listp->pref_offset == 0 ||
+ offset < listp->pref_offset) {
+ listp->pref_offset = offset;
+ }
+ } else {
+ /*
+ * The list could have got rescheduled while
+ * this thread was waiting for the lock
+ */
+ if (listp->scheduled) {
+ int32_t diff;
+ diff = timer_diff(listp->runtime, 0,
+ tcp_now, offset);
+ if (diff <= 0)
+ goto done;
+ else
+ goto schedule;
+ } else {
+ goto schedule;
+ }
+ }
+ }
+ goto done;
+
+schedule:
+ /*
+ * Since a connection with timers is getting scheduled, the timer
+ * list moves from idle to active state and that is why idlegen is
+ * reset
+ */
+ if (mode & TCP_TIMERLIST_10MS_MODE) {
+ listp->mode = TCP_TIMERLIST_10MS_MODE;
+ listp->idleruns = 0;
+ offset = min(offset, TCP_TIMER_10MS_QUANTUM);
+ } else if (mode & TCP_TIMERLIST_100MS_MODE) {
+ if (listp->mode > TCP_TIMERLIST_100MS_MODE)
+ listp->mode = TCP_TIMERLIST_100MS_MODE;
+ listp->idleruns = 0;
+ offset = min(offset, TCP_TIMER_100MS_QUANTUM);
+ }
+ tcp_sched_timerlist(offset);
+
+done:
+ if (list_locked)
+ lck_mtx_unlock(listp->mtx);
+
+ return;
+}
+
+static inline void
+tcp_set_lotimer_index(struct tcpcb *tp)
+{
+ uint16_t i, lo_index = TCPT_NONE, mode = 0;
+ uint32_t lo_timer = 0;
+ for (i = 0; i < TCPT_NTIMERS; ++i) {
+ if (tp->t_timer[i] != 0) {
+ TCP_SET_TIMER_MODE(mode, i);
+ if (lo_timer == 0 || tp->t_timer[i] < lo_timer) {
+ lo_timer = tp->t_timer[i];
+ lo_index = i;
+ }
+ }
+ }
+ tp->tentry.index = lo_index;
+ tp->tentry.mode = mode;
+ VERIFY(tp->tentry.index == TCPT_NONE || tp->tentry.mode > 0);
+
+ if (tp->tentry.index != TCPT_NONE) {
+ tp->tentry.runtime = tp->tentry.timer_start
+ + tp->t_timer[tp->tentry.index];
+ if (tp->tentry.runtime == 0)
+ tp->tentry.runtime++;
+ }
+}
+
+void
+tcp_check_timer_state(struct tcpcb *tp)
+{
+ lck_mtx_assert(&tp->t_inpcb->inpcb_mtx, LCK_MTX_ASSERT_OWNED);
+
+ if (tp->t_inpcb->inp_flags2 & INP2_TIMEWAIT)
+ return;
+
+ tcp_set_lotimer_index(tp);
+
+ tcp_sched_timers(tp);
+ return;
+}
+
+static inline void
+tcp_cumulative_stat(u_int32_t cur, u_int32_t *prev, u_int32_t *dest)
+{
+ /* handle wrap around */
+ int32_t diff = (int32_t) (cur - *prev);
+ if (diff > 0)
+ *dest = diff;
+ else
+ *dest = 0;
+ *prev = cur;
+ return;
+}
+
+__private_extern__ void
+tcp_report_stats(void)
+{
+ struct nstat_sysinfo_data data;
+ struct sockaddr_in dst;
+ struct sockaddr_in6 dst6;
+ struct rtentry *rt = NULL;
+ static struct tcp_last_report_stats prev;
+ u_int64_t var, uptime;
+
+#define stat data.u.tcp_stats
+ if (((uptime = net_uptime()) - tcp_last_report_time) <
+ tcp_report_stats_interval)
+ return;
+
+ tcp_last_report_time = uptime;
+
+ bzero(&data, sizeof(data));
+ data.flags = NSTAT_SYSINFO_TCP_STATS;
+
+ bzero(&dst, sizeof(dst));
+ dst.sin_len = sizeof(dst);
+ dst.sin_family = AF_INET;
+
+ /* ipv4 avg rtt */
+ lck_mtx_lock(rnh_lock);
+ rt = rt_lookup(TRUE, (struct sockaddr *)&dst, NULL,
+ rt_tables[AF_INET], IFSCOPE_NONE);
+ lck_mtx_unlock(rnh_lock);
+ if (rt != NULL) {
+ RT_LOCK(rt);
+ if (rt_primary_default(rt, rt_key(rt)) &&
+ rt->rt_stats != NULL) {
+ stat.ipv4_avgrtt = rt->rt_stats->nstat_avg_rtt;
+ }
+ RT_UNLOCK(rt);
+ rtfree(rt);
+ rt = NULL;
+ }
+
+ /* ipv6 avg rtt */
+ bzero(&dst6, sizeof(dst6));
+ dst6.sin6_len = sizeof(dst6);
+ dst6.sin6_family = AF_INET6;
+
+ lck_mtx_lock(rnh_lock);
+ rt = rt_lookup(TRUE,(struct sockaddr *)&dst6, NULL,
+ rt_tables[AF_INET6], IFSCOPE_NONE);
+ lck_mtx_unlock(rnh_lock);
+ if (rt != NULL) {
+ RT_LOCK(rt);
+ if (rt_primary_default(rt, rt_key(rt)) &&
+ rt->rt_stats != NULL) {
+ stat.ipv6_avgrtt = rt->rt_stats->nstat_avg_rtt;
+ }
+ RT_UNLOCK(rt);
+ rtfree(rt);
+ rt = NULL;
+ }
+
+ /* send packet loss rate, shift by 10 for precision */
+ if (tcpstat.tcps_sndpack > 0 && tcpstat.tcps_sndrexmitpack > 0) {
+ var = tcpstat.tcps_sndrexmitpack << 10;
+ stat.send_plr = (var * 100) / tcpstat.tcps_sndpack;
+ }
+
+ /* recv packet loss rate, shift by 10 for precision */
+ if (tcpstat.tcps_rcvpack > 0 && tcpstat.tcps_recovered_pkts > 0) {
+ var = tcpstat.tcps_recovered_pkts << 10;
+ stat.recv_plr = (var * 100) / tcpstat.tcps_rcvpack;
+ }
+
+ /* RTO after tail loss, shift by 10 for precision */
+ if (tcpstat.tcps_sndrexmitpack > 0
+ && tcpstat.tcps_tailloss_rto > 0) {
+ var = tcpstat.tcps_tailloss_rto << 10;
+ stat.send_tlrto_rate =
+ (var * 100) / tcpstat.tcps_sndrexmitpack;
+ }
+
+ /* packet reordering */
+ if (tcpstat.tcps_sndpack > 0 && tcpstat.tcps_reordered_pkts > 0) {
+ var = tcpstat.tcps_reordered_pkts << 10;
+ stat.send_reorder_rate =
+ (var * 100) / tcpstat.tcps_sndpack;
+ }
+
+ if (tcp_ecn_outbound == 1)
+ stat.ecn_client_enabled = 1;
+ if (tcp_ecn_inbound == 1)
+ stat.ecn_server_enabled = 1;
+ tcp_cumulative_stat(tcpstat.tcps_connattempt,
+ &prev.tcps_connattempt, &stat.connection_attempts);
+ tcp_cumulative_stat(tcpstat.tcps_accepts,
+ &prev.tcps_accepts, &stat.connection_accepts);
+ tcp_cumulative_stat(tcpstat.tcps_ecn_client_setup,
+ &prev.tcps_ecn_client_setup, &stat.ecn_client_setup);
+ tcp_cumulative_stat(tcpstat.tcps_ecn_server_setup,
+ &prev.tcps_ecn_server_setup, &stat.ecn_server_setup);
+ tcp_cumulative_stat(tcpstat.tcps_ecn_client_success,
+ &prev.tcps_ecn_client_success, &stat.ecn_client_success);
+ tcp_cumulative_stat(tcpstat.tcps_ecn_server_success,
+ &prev.tcps_ecn_server_success, &stat.ecn_server_success);
+ tcp_cumulative_stat(tcpstat.tcps_ecn_not_supported,
+ &prev.tcps_ecn_not_supported, &stat.ecn_not_supported);
+ tcp_cumulative_stat(tcpstat.tcps_ecn_lost_syn,
+ &prev.tcps_ecn_lost_syn, &stat.ecn_lost_syn);
+ tcp_cumulative_stat(tcpstat.tcps_ecn_lost_synack,
+ &prev.tcps_ecn_lost_synack, &stat.ecn_lost_synack);
+ tcp_cumulative_stat(tcpstat.tcps_ecn_recv_ce,
+ &prev.tcps_ecn_recv_ce, &stat.ecn_recv_ce);
+ tcp_cumulative_stat(tcpstat.tcps_ecn_recv_ece,
+ &prev.tcps_ecn_recv_ece, &stat.ecn_recv_ece);
+ tcp_cumulative_stat(tcpstat.tcps_ecn_recv_ece,
+ &prev.tcps_ecn_recv_ece, &stat.ecn_recv_ece);
+ tcp_cumulative_stat(tcpstat.tcps_ecn_sent_ece,
+ &prev.tcps_ecn_sent_ece, &stat.ecn_sent_ece);
+ tcp_cumulative_stat(tcpstat.tcps_ecn_sent_ece,
+ &prev.tcps_ecn_sent_ece, &stat.ecn_sent_ece);
+ tcp_cumulative_stat(tcpstat.tcps_ecn_conn_recv_ce,
+ &prev.tcps_ecn_conn_recv_ce, &stat.ecn_conn_recv_ce);
+ tcp_cumulative_stat(tcpstat.tcps_ecn_conn_recv_ece,
+ &prev.tcps_ecn_conn_recv_ece, &stat.ecn_conn_recv_ece);
+ tcp_cumulative_stat(tcpstat.tcps_ecn_conn_plnoce,
+ &prev.tcps_ecn_conn_plnoce, &stat.ecn_conn_plnoce);
+ tcp_cumulative_stat(tcpstat.tcps_ecn_conn_pl_ce,
+ &prev.tcps_ecn_conn_pl_ce, &stat.ecn_conn_pl_ce);
+ tcp_cumulative_stat(tcpstat.tcps_ecn_conn_nopl_ce,
+ &prev.tcps_ecn_conn_nopl_ce, &stat.ecn_conn_nopl_ce);
+ tcp_cumulative_stat(tcpstat.tcps_ecn_fallback_synloss,
+ &prev.tcps_ecn_fallback_synloss, &stat.ecn_fallback_synloss);
+ tcp_cumulative_stat(tcpstat.tcps_ecn_fallback_reorder,
+ &prev.tcps_ecn_fallback_reorder, &stat.ecn_fallback_reorder);
+ tcp_cumulative_stat(tcpstat.tcps_ecn_fallback_ce,
+ &prev.tcps_ecn_fallback_ce, &stat.ecn_fallback_ce);
+ tcp_cumulative_stat(tcpstat.tcps_tfo_syn_data_rcv,
+ &prev.tcps_tfo_syn_data_rcv, &stat.tfo_syn_data_rcv);
+ tcp_cumulative_stat(tcpstat.tcps_tfo_cookie_req_rcv,
+ &prev.tcps_tfo_cookie_req_rcv, &stat.tfo_cookie_req_rcv);
+ tcp_cumulative_stat(tcpstat.tcps_tfo_cookie_sent,
+ &prev.tcps_tfo_cookie_sent, &stat.tfo_cookie_sent);
+ tcp_cumulative_stat(tcpstat.tcps_tfo_cookie_invalid,
+ &prev.tcps_tfo_cookie_invalid, &stat.tfo_cookie_invalid);
+ tcp_cumulative_stat(tcpstat.tcps_tfo_cookie_req,
+ &prev.tcps_tfo_cookie_req, &stat.tfo_cookie_req);
+ tcp_cumulative_stat(tcpstat.tcps_tfo_cookie_rcv,
+ &prev.tcps_tfo_cookie_rcv, &stat.tfo_cookie_rcv);
+ tcp_cumulative_stat(tcpstat.tcps_tfo_syn_data_sent,
+ &prev.tcps_tfo_syn_data_sent, &stat.tfo_syn_data_sent);
+ tcp_cumulative_stat(tcpstat.tcps_tfo_syn_data_acked,
+ &prev.tcps_tfo_syn_data_acked, &stat.tfo_syn_data_acked);
+ tcp_cumulative_stat(tcpstat.tcps_tfo_syn_loss,
+ &prev.tcps_tfo_syn_loss, &stat.tfo_syn_loss);
+ tcp_cumulative_stat(tcpstat.tcps_tfo_blackhole,
+ &prev.tcps_tfo_blackhole, &stat.tfo_blackhole);
+ tcp_cumulative_stat(tcpstat.tcps_tfo_cookie_wrong,
+ &prev.tcps_tfo_cookie_wrong, &stat.tfo_cookie_wrong);
+ tcp_cumulative_stat(tcpstat.tcps_tfo_no_cookie_rcv,
+ &prev.tcps_tfo_no_cookie_rcv, &stat.tfo_no_cookie_rcv);
+ tcp_cumulative_stat(tcpstat.tcps_tfo_heuristics_disable,
+ &prev.tcps_tfo_heuristics_disable, &stat.tfo_heuristics_disable);
+ tcp_cumulative_stat(tcpstat.tcps_tfo_sndblackhole,
+ &prev.tcps_tfo_sndblackhole, &stat.tfo_sndblackhole);
+
+
+
+
+ nstat_sysinfo_send_data(&data);
+
+#undef stat
+}
+
+void
+tcp_interface_send_probe(u_int16_t probe_if_index)
+{
+ int32_t offset = 0;
+ struct tcptimerlist *listp = &tcp_timer_list;
+
+ /* Make sure TCP clock is up to date */
+ calculate_tcp_clock();
+
+ lck_mtx_lock(listp->mtx);
+ if (listp->probe_if_index > 0) {
+ tcpstat.tcps_probe_if_conflict++;
+ goto done;
+ }
+
+ listp->probe_if_index = probe_if_index;
+ if (listp->running)
+ goto done;
+
+ /*
+ * Reschedule the timerlist to run within the next 10ms, which is
+ * the fastest that we can do.
+ */
+ offset = TCP_TIMER_10MS_QUANTUM;
+ if (listp->scheduled) {
+ int32_t diff;
+ diff = timer_diff(listp->runtime, 0, tcp_now, offset);
+ if (diff <= 0) {
+ /* The timer will fire sooner than what's needed */
+ goto done;
+ }
+ }
+ listp->mode = TCP_TIMERLIST_10MS_MODE;
+ listp->idleruns = 0;
+
+ tcp_sched_timerlist(offset);
+
+done:
+ lck_mtx_unlock(listp->mtx);
+ return;
+}
+
+/*
+ * Enable read probes on this connection, if:
+ * - it is in established state
+ * - doesn't have any data outstanding
+ * - the outgoing ifp matches
+ * - we have not already sent any read probes
+ */
+static void
+tcp_enable_read_probe(struct tcpcb *tp, struct ifnet *ifp)
+{
+ if (tp->t_state == TCPS_ESTABLISHED &&
+ tp->snd_max == tp->snd_una &&
+ tp->t_inpcb->inp_last_outifp == ifp &&
+ !(tp->t_flagsext & TF_DETECT_READSTALL) &&
+ tp->t_rtimo_probes == 0) {
+ tp->t_flagsext |= TF_DETECT_READSTALL;
+ tp->t_rtimo_probes = 0;
+ tp->t_timer[TCPT_KEEP] = OFFSET_FROM_START(tp,
+ TCP_TIMER_10MS_QUANTUM);
+ if (tp->tentry.index == TCPT_NONE) {
+ tp->tentry.index = TCPT_KEEP;
+ tp->tentry.runtime = tcp_now +
+ TCP_TIMER_10MS_QUANTUM;
+ } else {
+ int32_t diff = 0;
+
+ /* Reset runtime to be in next 10ms */
+ diff = timer_diff(tp->tentry.runtime, 0,
+ tcp_now, TCP_TIMER_10MS_QUANTUM);
+ if (diff > 0) {
+ tp->tentry.index = TCPT_KEEP;
+ tp->tentry.runtime = tcp_now +
+ TCP_TIMER_10MS_QUANTUM;
+ if (tp->tentry.runtime == 0)
+ tp->tentry.runtime++;
+ }
+ }
+ }
+}
+
+/*
+ * Disable read probe and reset the keep alive timer
+ */
+static void
+tcp_disable_read_probe(struct tcpcb *tp)
+{
+ if (tp->t_adaptive_rtimo == 0 &&
+ ((tp->t_flagsext & TF_DETECT_READSTALL) ||
+ tp->t_rtimo_probes > 0)) {
+ tcp_keepalive_reset(tp);
+ }
+}
+
+/*
+ * Reschedule the tcp timerlist in the next 10ms to re-enable read/write
+ * probes on connections going over a particular interface.
+ */
+void
+tcp_probe_connectivity(struct ifnet *ifp, u_int32_t enable)
+{
+ int32_t offset;
+ struct tcptimerlist *listp = &tcp_timer_list;
+ struct inpcbinfo *pcbinfo = &tcbinfo;
+ struct inpcb *inp, *nxt;
+
+ if (ifp == NULL)
+ return;
+
+ /* update clock */
+ calculate_tcp_clock();
+
+ /*
+ * Enable keep alive timer on all connections that are
+ * active/established on this interface.
+ */
+ lck_rw_lock_shared(pcbinfo->ipi_lock);
+
+ LIST_FOREACH_SAFE(inp, pcbinfo->ipi_listhead, inp_list, nxt) {
+ struct tcpcb *tp = NULL;
+ if (in_pcb_checkstate(inp, WNT_ACQUIRE, 0) ==
+ WNT_STOPUSING)
+ continue;
+
+ /* Acquire lock to look at the state of the connection */
+ tcp_lock(inp->inp_socket, 1, 0);
+
+ /* Release the want count */
+ if (inp->inp_ppcb == NULL ||
+ (in_pcb_checkstate(inp, WNT_RELEASE, 1) == WNT_STOPUSING)) {
+ tcp_unlock(inp->inp_socket, 1, 0);
+ continue;
+ }
+ tp = intotcpcb(inp);
+ if (enable)
+ tcp_enable_read_probe(tp, ifp);
+ else
+ tcp_disable_read_probe(tp);
+
+ tcp_unlock(inp->inp_socket, 1, 0);
+ }
+ lck_rw_done(pcbinfo->ipi_lock);
+
+ lck_mtx_lock(listp->mtx);
+ if (listp->running) {
+ listp->pref_mode |= TCP_TIMERLIST_10MS_MODE;
+ goto done;
+ }
+
+ /* Reschedule within the next 10ms */
+ offset = TCP_TIMER_10MS_QUANTUM;
+ if (listp->scheduled) {
+ int32_t diff;
+ diff = timer_diff(listp->runtime, 0, tcp_now, offset);
+ if (diff <= 0) {
+ /* The timer will fire sooner than what's needed */
+ goto done;
+ }
+ }
+ listp->mode = TCP_TIMERLIST_10MS_MODE;
+ listp->idleruns = 0;
+
+ tcp_sched_timerlist(offset);
+done:
+ lck_mtx_unlock(listp->mtx);
+ return;
+}
+
+inline void
+tcp_update_mss_core(struct tcpcb *tp, struct ifnet *ifp)
+{
+ struct if_cellular_status_v1 *ifsr;
+ u_int32_t optlen;
+ ifsr = &ifp->if_link_status->ifsr_u.ifsr_cell.if_cell_u.if_status_v1;
+ if (ifsr->valid_bitmask & IF_CELL_UL_MSS_RECOMMENDED_VALID) {
+ optlen = tp->t_maxopd - tp->t_maxseg;
+
+ if (ifsr->mss_recommended ==
+ IF_CELL_UL_MSS_RECOMMENDED_NONE &&
+ tp->t_cached_maxopd > 0 &&
+ tp->t_maxopd < tp->t_cached_maxopd) {
+ tp->t_maxopd = tp->t_cached_maxopd;
+ tcpstat.tcps_mss_to_default++;
+ } else if (ifsr->mss_recommended ==
+ IF_CELL_UL_MSS_RECOMMENDED_MEDIUM &&
+ tp->t_maxopd > tcp_mss_rec_medium) {
+ tp->t_cached_maxopd = tp->t_maxopd;
+ tp->t_maxopd = tcp_mss_rec_medium;
+ tcpstat.tcps_mss_to_medium++;
+ } else if (ifsr->mss_recommended ==
+ IF_CELL_UL_MSS_RECOMMENDED_LOW &&
+ tp->t_maxopd > tcp_mss_rec_low) {
+ tp->t_cached_maxopd = tp->t_maxopd;
+ tp->t_maxopd = tcp_mss_rec_low;
+ tcpstat.tcps_mss_to_low++;
+ }
+ tp->t_maxseg = tp->t_maxopd - optlen;
+
+ /*
+ * clear the cached value if it is same as the current
+ */
+ if (tp->t_maxopd == tp->t_cached_maxopd)
+ tp->t_cached_maxopd = 0;
+ }
+}
+
+void
+tcp_update_mss_locked(struct socket *so, struct ifnet *ifp)
+{
+ struct inpcb *inp = sotoinpcb(so);
+ struct tcpcb *tp = intotcpcb(inp);
+
+ if (ifp == NULL && inp->inp_last_outifp == NULL)
+ return;
+
+ if (ifp == NULL)
+ ifp = inp->inp_last_outifp;
+
+ if (!IFNET_IS_CELLULAR(ifp)) {
+ /*
+ * This optimization is implemented for cellular
+ * networks only
+ */
+ return;
+ }
+ if ( tp->t_state <= TCPS_CLOSE_WAIT) {
+ /*
+ * If the connection is currently doing or has done PMTU
+ * blackhole detection, do not change the MSS
+ */
+ if (tp->t_flags & TF_BLACKHOLE)
+ return;
+ if (ifp->if_link_status == NULL)
+ return;
+ tcp_update_mss_core(tp, ifp);
+ }
+}
+
+void
+tcp_itimer(struct inpcbinfo *ipi)
+{
+ struct inpcb *inp, *nxt;
+
+ if (lck_rw_try_lock_exclusive(ipi->ipi_lock) == FALSE) {
+ if (tcp_itimer_done == TRUE) {
+ tcp_itimer_done = FALSE;
+ atomic_add_32(&ipi->ipi_timer_req.intimer_fast, 1);
+ return;
+ }
+ /* Upgrade failed, lost lock now take it again exclusive */
+ lck_rw_lock_exclusive(ipi->ipi_lock);
+ }
+ tcp_itimer_done = TRUE;
+
+ LIST_FOREACH_SAFE(inp, &tcb, inp_list, nxt) {
+ struct socket *so;
+
+ if (inp->inp_ppcb == NULL ||
+ in_pcb_checkstate(inp, WNT_ACQUIRE, 0) == WNT_STOPUSING)
+ continue;
+ so = inp->inp_socket;
+ tcp_lock(so, 1, 0);
+ if (in_pcb_checkstate(inp, WNT_RELEASE, 1) == WNT_STOPUSING) {
+ tcp_unlock(so, 1, 0);
+ continue;
+ }
+ so_check_extended_bk_idle_time(so);
+ if (ipi->ipi_flags & INPCBINFO_UPDATE_MSS) {
+ tcp_update_mss_locked(so, NULL);
+ }
+ tcp_unlock(so, 1, 0);
+ }
+
+ ipi->ipi_flags &= ~INPCBINFO_UPDATE_MSS;
+ lck_rw_done(ipi->ipi_lock);
+}
projects / apple / xnu.git / blobdiff