/*
- * Copyright (c) 2006 Apple Computer, Inc. All Rights Reserved.
+ * Copyright (c) 2000-2013 Apple Inc. All rights reserved.
+ *
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
- * @APPLE_LICENSE_OSREFERENCE_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.
*
- * 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, QUIET ENJOYMENT OR NON-INFRINGEMENT.
- * Please see the License for the specific language governing rights and
+ * 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, QUIET ENJOYMENT OR NON-INFRINGEMENT.
+ * Please see the License for the specific language governing rights and
* limitations under the License.
- *
- * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
+ *
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
/*
* Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995
#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 <netinet/in.h>
#include <netinet/in_systm.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>
+extern void postevent(struct socket *, struct sockbuf *,
+ int);
#define DBG_FNC_TCP_FAST NETDBG_CODE(DBG_NETTCP, (5 << 8))
#define DBG_FNC_TCP_SLOW NETDBG_CODE(DBG_NETTCP, (5 << 8) | 1)
-/*
- * NOTE - WARNING
- *
- *
- *
- *
- */
+#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)
+
+/* 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;
+
+static int background_io_trigger = 5;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, background_io_trigger, CTLFLAG_RW | CTLFLAG_LOCKED,
+ &background_io_trigger, 0, "Background IO Trigger Setting");
+
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 / hz;
+ s = tt * 1000 / TCP_RETRANSHZ;;
error = sysctl_handle_int(oidp, &s, 0, req);
if (error || !req->newptr)
return (error);
- tt = s * hz / 1000;
+ tt = s * TCP_RETRANSHZ / 1000;
if (tt < 1)
return (EINVAL);
}
int tcp_keepinit;
-SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINIT, keepinit, CTLTYPE_INT|CTLFLAG_RW,
+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,
+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,
+SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINTVL, keepintvl, CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_LOCKED,
&tcp_keepintvl, 0, sysctl_msec_to_ticks, "I", "");
-int tcp_delacktime;
-SYSCTL_PROC(_net_inet_tcp, TCPCTL_DELACKTIME, delacktime,
- CTLTYPE_INT|CTLFLAG_RW, &tcp_delacktime, 0, sysctl_msec_to_ticks, "I",
- "Time before a delayed ACK is sent");
-
+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_msl;
-SYSCTL_PROC(_net_inet_tcp, OID_AUTO, msl, CTLTYPE_INT|CTLFLAG_RW,
+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");
+/*
+ * 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 timout for ZWP");
+
static int always_keepalive = 0;
-SYSCTL_INT(_net_inet_tcp, OID_AUTO, always_keepalive, CTLFLAG_RW,
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, always_keepalive, CTLFLAG_RW | CTLFLAG_LOCKED,
&always_keepalive , 0, "Assume SO_KEEPALIVE on all TCP connections");
-static int tcp_keepcnt = TCPTV_KEEPCNT;
- /* max idle probes */
-int tcp_maxpersistidle;
- /* max idle time in persist */
-int tcp_maxidle;
+/* This parameter determines how long the timer list will stay in fast mode even
+ * though all connections are idle. In fast mode, the timer will fire more frequently
+ * anticipating new data.
+ */
+int timer_fastmode_idlemax = TCP_FASTMODE_IDLEGEN_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");
-struct inpcbhead time_wait_slots[N_TIME_WAIT_SLOTS];
-int cur_tw_slot = 0;
+/*
+ * 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 = 7;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, broken_peer_syn_rxmit_thres, CTLFLAG_RW | CTLFLAG_LOCKED,
+ &tcp_broken_peer_syn_rxmit_thres, 0, "Number of retransmitted SYNs before "
+ "TCP disables rfc1323 and rfc1644 during the rest of attempts");
-u_long *delack_bitmask;
+/* A higher threshold on local connections for disabling RFC 1323 options */
+static int tcp_broken_peer_syn_rxmit_thres_local = 10;
+SYSCTL_INT(_net_inet_tcp, OID_AUTO, broken_peer_syn_rexmit_thres_local,
+ CTLFLAG_RW | CTLFLAG_LOCKED, &tcp_broken_peer_syn_rxmit_thres_local, 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");
-void add_to_time_wait_locked(tp)
- struct tcpcb *tp;
-{
- int tw_slot;
+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");
- /* pcb list should be locked when we get here */
-#if 0
- lck_mtx_assert(tp->t_inpcb->inpcb_mtx, LCK_MTX_ASSERT_OWNED);
-#endif
+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");
- LIST_REMOVE(tp->t_inpcb, inp_list);
+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");
- 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_rcvtime += 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;
-void add_to_time_wait(tp)
- struct tcpcb *tp;
-{
- struct inpcbinfo *pcbinfo = &tcbinfo;
-
- if (!lck_rw_try_lock_exclusive(pcbinfo->mtx)) {
- tcp_unlock(tp->t_inpcb->inp_socket, 0, 0);
- lck_rw_lock_exclusive(pcbinfo->mtx);
- tcp_lock(tp->t_inpcb->inp_socket, 0, 0);
- }
- add_to_time_wait_locked(tp);
- lck_rw_done(pcbinfo->mtx);
-}
+#if MPTCP
+/*
+ * MP_JOIN retransmission of 3rd ACK will be every 500 msecs without backoff
+ */
+int tcp_jack_rxmt = TCP_RETRANSHZ / 2;
+#endif /* MPTCP */
+
+/* The frequency of running through the TCP timer list in
+ * fast and slow mode can be configured.
+ */
+SYSCTL_UINT(_net_inet_tcp, OID_AUTO, timer_fastquantum, CTLFLAG_RW | CTLFLAG_LOCKED,
+ &tcp_timer_list.fast_quantum, TCP_FASTTIMER_QUANTUM,
+ "Frequency of running timer list in fast mode");
+
+SYSCTL_UINT(_net_inet_tcp, OID_AUTO, timer_slowquantum, CTLFLAG_RW | CTLFLAG_LOCKED,
+ &tcp_timer_list.slow_quantum, TCP_SLOWTIMER_QUANTUM,
+ "Frequency of running timer list in slow mode");
+
+static void tcp_remove_timer(struct tcpcb *tp);
+static void tcp_sched_timerlist(uint32_t offset);
+static uint32_t tcp_run_conn_timer(struct tcpcb *tp, uint16_t *next_index);
+static void tcp_sched_timers(struct tcpcb *tp);
+static inline void tcp_set_lotimer_index(struct tcpcb *);
+static void tcp_rexmt_save_state(struct tcpcb *tp);
+void tcp_remove_from_time_wait(struct inpcb *inp);
+
+/* 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.
+ */
+
+static inline int32_t
+timer_diff(uint32_t t1, uint32_t toff1, uint32_t t2, uint32_t toff2) {
+ return (int32_t)((t1 + toff1) - (t2 + toff2));
+};
+
+/* Returns true if the timer is on the timer list */
+#define TIMER_IS_ON_LIST(tp) ((tp)->t_flags & TF_TIMER_ONLIST)
+static void add_to_time_wait_locked(struct tcpcb *tp, uint32_t delay);
+void add_to_time_wait(struct tcpcb *tp, uint32_t delay) ;
+static boolean_t tcp_garbage_collect(struct inpcb *, int);
/*
- * Fast timeout routine for processing delayed acks
+ * Add to tcp timewait list, delay is given in milliseconds.
*/
-void
-tcp_fasttimo()
+static void
+add_to_time_wait_locked(struct tcpcb *tp, uint32_t delay)
{
- struct inpcb *inp, *inpnxt;
- register struct tcpcb *tp;
-
-
- struct inpcbinfo *pcbinfo = &tcbinfo;
+ 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);
+ }
- int delack_checked = 0, delack_done = 0;
+ /* 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 */
- KERNEL_DEBUG(DBG_FNC_TCP_FAST | DBG_FUNC_START, 0,0,0,0,0);
+ if (TIMER_IS_ON_LIST(tp))
+ tcp_remove_timer(tp);
+ tp->t_timer[TCPT_2MSL] = timer;
- if (tcp_delack_enabled == 0)
- return;
+ TAILQ_INSERT_TAIL(&tcp_tw_tailq, tp, t_twentry);
+}
- lck_rw_lock_shared(pcbinfo->mtx);
+void
+add_to_time_wait(struct tcpcb *tp, uint32_t delay)
+{
+ struct inpcbinfo *pcbinfo = &tcbinfo;
- /* Walk the list of valid tcpcbs and send ACKS on the ones with DELACK bit set */
+ 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);
- for (inp = tcb.lh_first; inp != NULL; inp = inpnxt) {
- inpnxt = inp->inp_list.le_next;
- /* NOTE: it's OK to check the tp because the pcb can't be removed while we hold pcbinfo->mtx) */
- if ((tp = (struct tcpcb *)inp->inp_ppcb) && (tp->t_flags & TF_DELACK)) {
- if (in_pcb_checkstate(inp, WNT_ACQUIRE, 0) == WNT_STOPUSING)
- continue;
- tcp_lock(inp->inp_socket, 1, 0);
- if (in_pcb_checkstate(inp, WNT_RELEASE, 1) == WNT_STOPUSING) {
- tcp_unlock(inp->inp_socket, 1, 0);
- continue;
- }
- if (tp->t_flags & TF_DELACK) {
- delack_done++;
- tp->t_flags &= ~TF_DELACK;
- tp->t_flags |= TF_ACKNOW;
- tcpstat.tcps_delack++;
- (void) tcp_output(tp);
- }
- tcp_unlock(inp->inp_socket, 1, 0);
- }
- }
- KERNEL_DEBUG(DBG_FNC_TCP_FAST | DBG_FUNC_END, delack_checked, delack_done, tcpstat.tcps_delack,0,0);
- lck_rw_done(pcbinfo->mtx);
+ inpcb_gc_sched(pcbinfo, INPCB_TIMER_LAZY);
}
-/*
- * 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.
- */
+/* If this is on time wait queue, remove it. */
void
-tcp_slowtimo()
+tcp_remove_from_time_wait(struct inpcb *inp)
{
- struct inpcb *inp, *inpnxt;
- struct tcpcb *tp;
- struct socket *so;
- int i;
-#if TCPDEBUG
- int ostate;
-#endif
-#if KDEBUG
- static int tws_checked;
-#endif
- struct inpcbinfo *pcbinfo = &tcbinfo;
-
- KERNEL_DEBUG(DBG_FNC_TCP_SLOW | DBG_FUNC_START, 0,0,0,0,0);
+ struct tcpcb *tp = intotcpcb(inp);
+ if (inp->inp_flags2 & INP2_TIMEWAIT)
+ TAILQ_REMOVE(&tcp_tw_tailq, tp, t_twentry);
+}
- tcp_maxidle = tcp_keepcnt * tcp_keepintvl;
+static boolean_t
+tcp_garbage_collect(struct inpcb *inp, int istimewait)
+{
+ boolean_t active = FALSE;
+ struct socket *so;
+ struct tcpcb *tp;
- lck_rw_lock_shared(pcbinfo->mtx);
+ so = inp->inp_socket;
+ tp = intotcpcb(inp);
/*
- * Search through tcb's and update active timers.
+ * 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.
*/
- for (inp = tcb.lh_first; inp != NULL; inp = inpnxt) {
- inpnxt = inp->inp_list.le_next;
-
- so = inp->inp_socket;
+ 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 (so == &tcbinfo.nat_dummy_socket)
- continue;
+ 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);
+ }
- if (in_pcb_checkstate(inp, WNT_ACQUIRE,0) == WNT_STOPUSING)
- continue;
+ /*
+ * 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
+ *
+ */
+ 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);
+ }
+ 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);
+ }
- tcp_lock(so, 1, 0);
+ /*
+ * 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 ((in_pcb_checkstate(inp, WNT_RELEASE,1) == WNT_STOPUSING) && so->so_usecount == 1) {
- tcp_unlock(so, 1, 0);
- continue;
+ /*
+ * If this tp still happens to be on the timer list,
+ * take it out
+ */
+ if (TIMER_IS_ON_LIST(tp)) {
+ tcp_remove_timer(tp);
}
- tp = intotcpcb(inp);
- if (tp == 0 || tp->t_state == TCPS_LISTEN) {
- tcp_unlock(so, 1, 0);
- continue;
+
+ 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);
}
+ in_pcbdispose(inp);
+ return (FALSE);
+ }
+
+ lck_mtx_unlock(&inp->inpcb_mtx);
+ return (TRUE);
+}
- for (i = 0; i < TCPT_NTIMERS; i++) {
- if (tp->t_timer[i] && --tp->t_timer[i] == 0) {
+/*
+ * 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
- ostate = tp->t_state;
+ int ostate;
#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);
+#if KDEBUG
+ static int tws_checked = 0;
#endif
- }
- }
- tp->t_rcvtime++;
- tp->t_starttime++;
- if (tp->t_rtttime)
- tp->t_rtttime++;
-tpgone:
- tcp_unlock(so, 1, 0);
- }
-#if KDEBUG
- tws_checked = 0;
-#endif
- KERNEL_DEBUG(DBG_FNC_TCP_SLOW | DBG_FUNC_NONE, tws_checked,0,0,0,0);
+ 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 (inp = time_wait_slots[cur_tw_slot].lh_first; inp; inp = inpnxt)
- {
- inpnxt = inp->inp_list.le_next;
-#if KDEBUG
- tws_checked++;
-#endif
-
- if (in_pcb_checkstate(inp, WNT_ACQUIRE, 0) == WNT_STOPUSING)
- continue;
-
- tcp_lock(inp->inp_socket, 1, 0);
-
- if (in_pcb_checkstate(inp, WNT_RELEASE, 1) == WNT_STOPUSING)
- goto twunlock;
+ /*
+ * Garbage collect socket/tcpcb: We need to acquire the list lock
+ * exclusively to do this
+ */
- tp = intotcpcb(inp);
- if (tp == NULL) { /* tp already closed, remove from list */
-#if TEMPDEBUG
- printf("tcp_slowtimo: tp is null in time-wait slot!\n");
-#endif
- goto twunlock;
- }
- if (tp->t_timer[TCPT_2MSL] >= N_TIME_WAIT_SLOTS) {
- tp->t_timer[TCPT_2MSL] -= N_TIME_WAIT_SLOTS;
- tp->t_rcvtime += N_TIME_WAIT_SLOTS;
+ 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;
-
- if (tp->t_timer[TCPT_2MSL] == 0)
- tp = tcp_timers(tp, TCPT_2MSL); /* tp can be returned null if tcp_close is called */
-twunlock:
- tcp_unlock(inp->inp_socket, 1, 0);
+ /* Upgrade failed, lost lock now take it again exclusive */
+ lck_rw_lock_exclusive(ipi->ipi_lock);
}
+ tcp_gc_done = TRUE;
- if (lck_rw_lock_shared_to_exclusive(pcbinfo->mtx) != 0)
- lck_rw_lock_exclusive(pcbinfo->mtx); /* Upgrade failed, lost lock no take it again exclusive */
-
-
- for (inp = tcb.lh_first; inp != NULL; inp = inpnxt) {
- inpnxt = inp->inp_list.le_next;
- /* Ignore nat/SharedIP dummy pcbs */
- if (inp->inp_socket == &tcbinfo.nat_dummy_socket)
- continue;
-
- if (inp->inp_wantcnt != WNT_STOPUSING)
- continue;
-
- so = inp->inp_socket;
- if (!lck_mtx_try_lock(inp->inpcb_mtx)) {/* skip if in use */
-#if TEMPDEBUG
- printf("tcp_slowtimo so=%x STOPUSING but locked...\n", so);
-#endif
- continue;
- }
+ 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 (so->so_usecount == 0)
- in_pcbdispose(inp);
- else {
- tp = intotcpcb(inp);
- /* Check for embryonic socket stuck on listener queue (4023660) */
- if ((so->so_usecount == 1) && (tp->t_state == TCPS_CLOSED) &&
- (so->so_head != NULL) && (so->so_state & SS_INCOMP)) {
- so->so_usecount--;
- in_pcbdispose(inp);
- } else
- lck_mtx_unlock(inp->inpcb_mtx);
+ /* 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.
+ */
+ if (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);
+ } else {
+ break;
}
}
- /* Now cleanup the time wait ones */
- for (inp = time_wait_slots[cur_tw_slot].lh_first; inp; inp = inpnxt)
- {
- inpnxt = inp->inp_list.le_next;
+ /* take into account pcbs that are still in time_wait_slots */
+ atomic_add_32(&ipi->ipi_gc_req.intimer_lazy, ipi->ipi_twcount);
- if (inp->inp_wantcnt != WNT_STOPUSING)
- continue;
+ lck_rw_done(ipi->ipi_lock);
- so = inp->inp_socket;
- if (!lck_mtx_try_lock(inp->inpcb_mtx)) /* skip if in use */
- continue;
- if (so->so_usecount == 0)
- in_pcbdispose(inp);
- else {
- tp = intotcpcb(inp);
- /* Check for embryonic socket stuck on listener queue (4023660) */
- if ((so->so_usecount == 1) && (tp->t_state == TCPS_CLOSED) &&
- (so->so_head != NULL) && (so->so_state & SS_INCOMP)) {
- so->so_usecount--;
- in_pcbdispose(inp);
- } else
- lck_mtx_unlock(inp->inpcb_mtx);
- }
- }
-
- tcp_now++;
- if (++cur_tw_slot >= N_TIME_WAIT_SLOTS)
- cur_tw_slot = 0;
-
- lck_rw_done(pcbinfo->mtx);
- KERNEL_DEBUG(DBG_FNC_TCP_SLOW | DBG_FUNC_END, tws_checked, cur_tw_slot,0,0,0);
+ /* 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;
}
/*
{
register 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] =
static int tcp_totbackoff = 511; /* sum of tcp_backoff[] */
+static 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);
+}
+
/*
* TCP timer processing.
*/
int timer;
{
register int rexmt;
- struct socket *so_tmp;
+ struct socket *so;
struct tcptemp *t_template;
+ int optlen = 0;
+ int idle_time = 0;
#if TCPDEBUG
int ostate;
int isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV4) == 0;
#endif /* INET6 */
- so_tmp = tp->t_inpcb->inp_socket;
+ 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_rcvtime <= tcp_maxidle) {
- tp->t_timer[TCPT_2MSL] = (unsigned long)tcp_keepintvl;
- add_to_time_wait_locked(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);
}
* to a longer retransmit interval and retransmit one segment.
*/
case TCPT_REXMT:
- tcp_free_sackholes(tp);
- if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) {
+ /* 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)) {
+
+ if ((tp->t_flagsext & TF_RXTFINDROP) != 0) {
+ tcpstat.tcps_rxtfindrop++;
+ } else {
+ tcpstat.tcps_timeoutdrop++;
+ }
tp->t_rxtshift = 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);
- postevent(so_tmp, 0, EV_TIMEOUT);
+
break;
}
- if (tp->t_rxtshift == 1) {
- /*
- * first retransmit; 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_badrxtwin = tcp_now + (tp->t_srtt >> (TCP_RTT_SHIFT + 1));
- }
tcpstat.tcps_rexmttimeo++;
- if (tp->t_state == TCPS_SYN_SENT)
+
+ 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 (tp->t_state == TCPS_SYN_SENT) {
rexmt = TCP_REXMTVAL(tp) * tcp_syn_backoff[tp->t_rxtshift];
+ tp->t_stat.synrxtshift = tp->t_rxtshift;
+ }
else
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_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);
/*
- * Disable rfc1323 and rfc1644 if we havn't got any response to
- * our third SYN 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.
+ * Check for potential Path MTU Discovery Black Hole
*/
- if ((tp->t_state == TCPS_SYN_SENT) && (tp->t_rxtshift == 3))
- tp->t_flags &= ~(TF_REQ_SCALE|TF_REQ_TSTMP|TF_REQ_CC);
+
+ if (tcp_pmtud_black_hole_detect && (tp->t_state == TCPS_ESTABLISHED)) {
+ if (((tp->t_flags & (TF_PMTUD|TF_MAXSEGSNT)) == (TF_PMTUD|TF_MAXSEGSNT)) &&
+ (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 negociated with 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;
+ /* 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);
+ }
+ /*
+ * 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)) {
+ 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);
+ }
+ }
+ }
+
+
+ /*
+ * 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_flags & TF_LOCAL) &&
+ tp->t_rxtshift == tcp_broken_peer_syn_rxmit_thres) ||
+ ((tp->t_flags & TF_LOCAL) &&
+ tp->t_rxtshift == tcp_broken_peer_syn_rxmit_thres_local)))
+ 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,
* If timing a segment in this window, stop the timer.
*/
tp->t_rtttime = 0;
- /*
- * 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.)
+
+ EXIT_FASTRECOVERY(tp);
+
+ /* 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
+ */
+ 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
+ * RTOs, Fast Retransmits and ECE notification receipts.
*/
- {
- 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->ecn_flags & TE_ECN_ON) == TE_ECN_ON) {
+ tp->ecn_flags |= TE_SENDCWR;
}
- EXIT_FASTRECOVERY(tp);
+fc_output:
+ DTRACE_TCP5(cc, void, NULL, struct inpcb *, tp->t_inpcb,
+ struct tcpcb *, tp, struct tcphdr *, NULL,
+ int32_t, 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_rcvtime >= tcp_maxpersistidle ||
- tp->t_rcvtime >= 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);
*/
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) &&
+ (mp_tp == NULL)) {
+ 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 || tp->t_state == TCPS_FIN_WAIT_2) {
- if (tp->t_rcvtime >= TCP_KEEPIDLE(tp) + (unsigned long)tcp_maxidle)
+ (tp->t_inpcb->inp_socket->so_options & SO_KEEPALIVE) ||
+ (tp->t_flagsext & TF_DETECT_READSTALL)) &&
+ (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
tcpstat.tcps_keepprobe++;
t_template = tcp_maketemplate(tp);
if (t_template) {
+ unsigned int ifscope, nocell = 0;
+
+ if (tp->t_inpcb->inp_flags & INP_BOUND_IF)
+ ifscope = tp->t_inpcb->inp_boundifp->if_index;
+ else
+ ifscope = IFSCOPE_NONE;
+
+ /*
+ * If the socket isn't allowed to use the
+ * cellular interface, indicate it as such.
+ */
+ if (tp->t_inpcb->inp_flags & INP_NO_IFT_CELLULAR)
+ nocell = 1;
+
tcp_respond(tp, t_template->tt_ipgen,
&t_template->tt_t, (struct mbuf *)NULL,
- tp->rcv_nxt, tp->snd_una - 1, 0);
+ tp->rcv_nxt, tp->snd_una - 1, 0, ifscope,
+ nocell);
(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) {
+ /*
+ * 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 (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 {
+ tp->t_timer[TCPT_KEEP] = OFFSET_FROM_START(
+ tp, TCP_REXMTVAL(tp));
}
- tp->t_timer[TCPT_KEEP] = tcp_keepintvl;
- } else
- tp->t_timer[TCPT_KEEP] = TCP_KEEPIDLE(tp);
+ }
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
+ * go back to acking every other packet
+ */
+ if ((tp->t_flags & TF_STRETCHACK) != 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 */
#if TCPDEBUG
if (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)
#endif
dropit:
tcpstat.tcps_keepdrops++;
+ 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;
}
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(uint32_t runtime, uint16_t index) {
+ struct tcptimerlist *listp = &tcp_timer_list;
+ int32_t diff;
+ boolean_t is_fast;
+
+ if (runtime == 0 || index == TCPT_NONE)
+ return FALSE;
+ is_fast = !(IS_TIMER_SLOW(index));
+
+ /* 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;
+ }
+
+ diff = timer_diff(listp->runtime, 0, runtime, 0);
+ if (diff <= 0) {
+ /* The list is going to run before this timer */
+ return FALSE;
+ } else {
+ if (is_fast) {
+ if (diff <= listp->fast_quantum)
+ return FALSE;
+ } else {
+ if (diff <= listp->slow_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);
+
+ listp->runtime = tcp_now + offset;
+
+ clock_interval_to_deadline(offset, NSEC_PER_SEC / TCP_RETRANSHZ,
+ &deadline);
+
+ thread_call_enter_delayed(listp->call, deadline);
+}
+
+/* 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.
+ */
+uint32_t
+tcp_run_conn_timer(struct tcpcb *tp, uint16_t *next_index) {
+
+ struct socket *so;
+ uint16_t i = 0, index = TCPT_NONE, lo_index = TCPT_NONE;
+ uint32_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));
+
+ 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;
+ }
+
+ /* 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.
+ */
+ index = tp->tentry.index;
+ timer_val = tp->t_timer[index];
+
+ if (index == TCPT_NONE || tp->tentry.runtime == 0)
+ goto done;
+
+ diff = timer_diff(tp->tentry.runtime, 0, tcp_now, 0);
+ if (diff > 0) {
+ if (tp->tentry.index != TCPT_NONE) {
+ offset = diff;
+ *(next_index) = tp->tentry.index;
+ }
+ 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.
+ */
+ 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) {
+ tp->t_timer[i] = 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;
+ }
+ }
+ }
+ }
+
+ tp->tentry.timer_start = tcp_now;
+ tp->tentry.index = lo_index;
+ if (lo_index != TCPT_NONE) {
+ tp->tentry.runtime = tp->tentry.timer_start + tp->t_timer[lo_index];
+ } else {
+ tp->tentry.runtime = 0;
+ }
+
+ if (count > 0) {
+ /* run any other timers that are also 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)
+ goto done;
+ }
+ }
+ tcp_set_lotimer_index(tp);
+ }
+
+ if (tp->tentry.index < TCPT_NONE) {
+ offset = tp->t_timer[tp->tentry.index];
+ *(next_index) = tp->tentry.index;
+ }
+
+done:
+ if (tp != NULL && tp->tentry.index == TCPT_NONE) {
+ tcp_remove_timer(tp);
+ }
+ 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;
+ uint16_t index = TCPT_NONE;
+ boolean_t need_fast = FALSE;
+ uint32_t active_count = 0;
+ uint32_t mode = TCP_TIMERLIST_FASTMODE;
+
+ 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 (TSTMP_GT(runtime, tcp_now)) {
+ offset = timer_diff(runtime, 0, tcp_now, 0);
+ if (next_timer == 0 || offset < next_timer) {
+ next_timer = offset;
+ }
+ continue;
+ }
+ active_count++;
+
+ 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
+ */
+ 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;
+ }
+
+ /* 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);
+
+ index = TCPT_NONE;
+ offset = tcp_run_conn_timer(tp, &index);
+
+ lck_mtx_lock(listp->mtx);
+
+ next_te = listp->next_te;
+ listp->next_te = NULL;
+
+ if (offset > 0) {
+ if (index < TCPT_NONE) {
+ /* Check if this is a fast_timer. */
+ if (!need_fast && !(IS_TIMER_SLOW(index))) {
+ need_fast = TRUE;
+ }
+
+ if (next_timer == 0 || offset < next_timer) {
+ next_timer = offset;
+ }
+ }
+ }
+ }
+
+ if (!LIST_EMPTY(&listp->lhead)) {
+ if (listp->mode == TCP_TIMERLIST_FASTMODE) {
+ if (need_fast || active_count > 0 ||
+ listp->pref_mode == TCP_TIMERLIST_FASTMODE) {
+ listp->idlegen = 0;
+ } else {
+ listp->idlegen++;
+ if (listp->idlegen > timer_fastmode_idlemax) {
+ mode = TCP_TIMERLIST_SLOWMODE;
+ listp->idlegen = 0;
+ }
+ }
+ } else {
+ if (!need_fast) {
+ mode = TCP_TIMERLIST_SLOWMODE;
+ }
+ }
+
+ if (mode == TCP_TIMERLIST_FASTMODE ||
+ listp->pref_mode == TCP_TIMERLIST_FASTMODE) {
+ next_timer = listp->fast_quantum;
+ } else {
+ if (listp->pref_offset != 0 &&
+ listp->pref_offset < next_timer)
+ next_timer = listp->pref_offset;
+ if (next_timer < listp->slow_quantum)
+ next_timer = listp->slow_quantum;
+ }
+
+ listp->mode = mode;
+
+ tcp_sched_timerlist(next_timer);
+ } else {
+ /* No need to reschedule this timer */
+ listp->runtime = 0;
+ }
+
+ listp->running = FALSE;
+ listp->pref_mode = 0;
+ listp->pref_offset = 0;
+
+ lck_mtx_unlock(listp->mtx);
+}
+
+/* Function to verify if a change in timer state is required for a connection */
+void
+tcp_sched_timers(struct tcpcb *tp)
+{
+ struct tcptimerentry *te = &tp->tentry;
+ uint16_t index = te->index;
+ struct tcptimerlist *listp = &tcp_timer_list;
+ uint32_t offset = 0;
+ boolean_t is_fast;
+ int list_locked = 0;
+
+ 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) {
+ tcp_remove_timer(tp);
+ return;
+ }
+
+ is_fast = !(IS_TIMER_SLOW(index));
+ offset = te->runtime - tcp_now;
+ if (offset == 0) {
+ offset = 1;
+ tcp_timer_advanced++;
+ }
+ if (is_fast)
+ offset = listp->fast_quantum;
+
+ if (!TIMER_IS_ON_LIST(tp)) {
+ if (!list_locked) {
+ lck_mtx_lock(listp->mtx);
+ list_locked = 1;
+ }
+
+ 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->runtime == 0)
+ goto schedule;
+
+ }
+
+
+ /* timer entry is currently on the list */
+ if (need_to_resched_timerlist(te->runtime, index)) {
+ tcp_resched_timerlist++;
+
+ if (!list_locked) {
+ lck_mtx_lock(listp->mtx);
+ list_locked = 1;
+ }
+
+ VERIFY_NEXT_LINK(te, le);
+ VERIFY_PREV_LINK(te, le);
+
+ if (listp->running) {
+ if (is_fast) {
+ listp->pref_mode = TCP_TIMERLIST_FASTMODE;
+ } else if (listp->pref_offset == 0 ||
+ ((int)offset) < listp->pref_offset) {
+ listp->pref_offset = offset;
+ }
+ } else {
+ int32_t diff;
+ diff = timer_diff(listp->runtime, 0, tcp_now, offset);
+ if (diff <= 0) {
+ /* The list is going to run before this timer */
+ goto done;
+ } else {
+ goto schedule;
+ }
+ }
+ }
+ goto done;
+
+schedule:
+ if (is_fast) {
+ listp->mode = TCP_TIMERLIST_FASTMODE;
+ listp->idlegen = 0;
+ }
+ tcp_sched_timerlist(offset);
+
+done:
+ if (list_locked)
+ lck_mtx_unlock(listp->mtx);
+
+ return;
+}
+
+void
+tcp_set_lotimer_index(struct tcpcb *tp) {
+ uint16_t i, lo_index = TCPT_NONE;
+ uint32_t lo_timer = 0;
+ for (i = 0; i < TCPT_NTIMERS; ++i) {
+ if (tp->t_timer[i] != 0 &&
+ (lo_timer == 0 || tp->t_timer[i] < lo_timer)) {
+ lo_timer = tp->t_timer[i];
+ lo_index = i;
+ }
+ }
+ tp->tentry.index = lo_index;
+ if (lo_index != TCPT_NONE) {
+ tp->tentry.runtime = tp->tentry.timer_start + tp->t_timer[lo_index];
+ } else {
+ tp->tentry.runtime = 0;
+ }
+}
+
+void
+tcp_check_timer_state(struct tcpcb *tp) {
+
+ lck_mtx_assert(&tp->t_inpcb->inpcb_mtx, LCK_MTX_ASSERT_OWNED);
+
+ tcp_set_lotimer_index(tp);
+
+ tcp_sched_timers(tp);
+ return;
+}
projects / apple / xnu.git / blobdiff