X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/ab86ba338a07a58a89f50cf7066a0f0e487ac0cc..b0d623f7f2ae71ed96e60569f61f9a9a27016e80:/bsd/netinet/tcp_timer.c diff --git a/bsd/netinet/tcp_timer.c b/bsd/netinet/tcp_timer.c index b7840d882..e77c28f86 100644 --- a/bsd/netinet/tcp_timer.c +++ b/bsd/netinet/tcp_timer.c @@ -1,16 +1,19 @@ /* - * Copyright (c) 2000 Apple Computer, Inc. All rights reserved. + * Copyright (c) 2000-2008 Apple Inc. All rights reserved. * - * @APPLE_LICENSE_HEADER_START@ - * - * Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved. + * @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. Please obtain a copy of the License at - * http://www.opensource.apple.com/apsl/ and read it before using this - * file. + * 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 @@ -20,7 +23,7 @@ * Please see the License for the specific language governing rights and * limitations under the License. * - * @APPLE_LICENSE_HEADER_END@ + * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ /* * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 @@ -67,6 +70,8 @@ #include #include #include +#include +#include #include /* before tcp_seq.h, for tcp_random18() */ @@ -84,15 +89,24 @@ #include #include #include +#if INET6 +#include +#endif #include #if TCPDEBUG #include #endif #include +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) +static int background_io_trigger = 5; +SYSCTL_INT(_net_inet_tcp, OID_AUTO, background_io_trigger, CTLFLAG_RW, + &background_io_trigger, 0, "Background IO Trigger Setting"); + /* * NOTE - WARNING * @@ -103,16 +117,17 @@ 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); @@ -132,11 +147,6 @@ int tcp_keepintvl; SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINTVL, keepintvl, CTLTYPE_INT|CTLFLAG_RW, &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_msl; SYSCTL_PROC(_net_inet_tcp, OID_AUTO, msl, CTLTYPE_INT|CTLFLAG_RW, &tcp_msl, 0, sysctl_msec_to_ticks, "I", "Maximum segment lifetime"); @@ -145,7 +155,28 @@ static int always_keepalive = 0; SYSCTL_INT(_net_inet_tcp, OID_AUTO, always_keepalive, CTLFLAG_RW, &always_keepalive , 0, "Assume SO_KEEPALIVE on all TCP connections"); +/* + * 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, + &tcp_broken_peer_syn_rxmit_thres, 0, "Number of retransmitted SYNs before " + "TCP disables rfc1323 and rfc1644 during the rest of attempts"); + +int tcp_pmtud_black_hole_detect = 1 ; +SYSCTL_INT(_net_inet_tcp, OID_AUTO, pmtud_blackhole_detection, CTLFLAG_RW, + &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, + &tcp_pmtud_black_hole_mss, 0, "Path MTU Discovery Black Hole Detection lowered MSS"); + static int tcp_keepcnt = TCPTV_KEEPCNT; +static int tcp_gc_done = FALSE; /* perfromed garbage collection of "used" sockets */ /* max idle probes */ int tcp_maxpersistidle; /* max idle time in persist */ @@ -154,20 +185,37 @@ int tcp_maxidle; struct inpcbhead time_wait_slots[N_TIME_WAIT_SLOTS]; int cur_tw_slot = 0; -u_long *delack_bitmask; +u_int32_t *delack_bitmask; +void add_to_time_wait_locked(struct tcpcb *tp); +void add_to_time_wait(struct tcpcb *tp) ; -void add_to_time_wait(tp) - struct tcpcb *tp; +static void tcp_garbage_collect(struct inpcb *, int); + +void add_to_time_wait_locked(struct tcpcb *tp) { int tw_slot; + struct inpcbinfo *pcbinfo = &tcbinfo; + + /* pcb list should be locked when we get here */ + lck_rw_assert(pcbinfo->mtx, LCK_RW_ASSERT_EXCLUSIVE); LIST_REMOVE(tp->t_inpcb, inp_list); - if (tp->t_timer[TCPT_2MSL] == 0) + if (tp->t_timer[TCPT_2MSL] <= 0) tp->t_timer[TCPT_2MSL] = 1; - tp->t_rcvtime += tp->t_timer[TCPT_2MSL] & (N_TIME_WAIT_SLOTS - 1); + /* + * Because we're pulling this pcb out of the main TCP pcb list, + * we need to recalculate the TCPT_2MSL timer value for tcp_slowtimo + * higher timer granularity. + */ + + tp->t_timer[TCPT_2MSL] = (tp->t_timer[TCPT_2MSL] / TCP_RETRANSHZ) * PR_SLOWHZ; + tp->t_rcvtime = (tp->t_rcvtime / TCP_RETRANSHZ) * PR_SLOWHZ; + + 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; @@ -175,6 +223,18 @@ void add_to_time_wait(tp) LIST_INSERT_HEAD(&time_wait_slots[tw_slot], tp->t_inpcb, inp_list); } +void add_to_time_wait(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); +} @@ -183,143 +243,337 @@ void add_to_time_wait(tp) * Fast timeout routine for processing delayed acks */ void -tcp_fasttimo() +tcp_fasttimo(void *arg) { - register struct inpcb *inp; +#pragma unused(arg) + struct inpcb *inp; register struct tcpcb *tp; + struct socket *so; +#if TCPDEBUG + int ostate; +#endif - register u_long i,j; - register u_long temp_mask; - register u_long elem_base = 0; - struct inpcbhead *head; - int s = splnet(); + struct inpcbinfo *pcbinfo = &tcbinfo; - static - int delack_checked = 0; + int delack_done = 0; KERNEL_DEBUG(DBG_FNC_TCP_FAST | DBG_FUNC_START, 0,0,0,0,0); - if (!tcp_delack_enabled) - return; - - 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); - } - } - } - temp_mask <<= 1; - } - delack_bitmask[i] = 0; - } - elem_base += 32; + + lck_rw_lock_shared(pcbinfo->mtx); + + /* Walk the list of valid tcpcbs and send ACKS on the ones with DELACK bit set */ + + LIST_FOREACH(inp, &tcb, inp_list) { + + so = inp->inp_socket; + + if (in_pcb_checkstate(inp, WNT_ACQUIRE, 0) == WNT_STOPUSING) + continue; + + tcp_lock(so, 1, 0); + + if ((in_pcb_checkstate(inp, WNT_RELEASE,1) == WNT_STOPUSING) && so->so_usecount == 1) { + tcp_unlock(so, 1, 0); + continue; + } + + tp = intotcpcb(inp); + + if (tp == 0 || tp->t_state == TCPS_LISTEN) { + tcp_unlock(so, 1, 0); + continue; + } + + + /* Only run the retransmit timer in that case */ + if (tp->t_timer[0] && --tp->t_timer[0] == 0) { + tp = tcp_timers(tp, 0); + if (tp == NULL) + goto tpgone; + } + + /* TCP pcb timers following the tcp_now clock rate */ + + tp->t_rcvtime++; + tp->t_starttime++; + if (tp->t_rtttime) + tp->t_rtttime++; + + /* + * Process delayed acks (if enabled) according to PR_FASTHZ, not the retrans timer + */ + + if (tcp_delack_enabled && (tcp_now % (TCP_RETRANSHZ/PR_FASTHZ)) && tp->t_flags & TF_DELACK) { + delack_done++; + tp->t_flags &= ~TF_DELACK; + tp->t_flags |= TF_ACKNOW; + tcpstat.tcps_delack++; + tp->t_unacksegs = 0; + (void) tcp_output(tp); + } +tpgone: + tcp_unlock(so, 1, 0); } - KERNEL_DEBUG(DBG_FNC_TCP_FAST | DBG_FUNC_END, delack_checked,tcpstat.tcps_delack,0,0,0); - splx(s); + KERNEL_DEBUG(DBG_FNC_TCP_FAST | DBG_FUNC_END, delack_done, 0, tcpstat.tcps_delack,0,0); + lck_rw_done(pcbinfo->mtx); + tcp_now++; + timeout(tcp_fasttimo, 0, hz/TCP_RETRANSHZ); } -/* - * 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. - */ +static void +tcp_garbage_collect(struct inpcb *inp, int istimewait) +{ + 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 (so->so_usecount > 1 || !lck_mtx_try_lock_spin(inp->inpcb_mtx)) + return; + + /* Check again under the lock */ + if (so->so_usecount > 1) { + lck_mtx_unlock(inp->inpcb_mtx); + return; + } + + /* + * 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 (INP_CHECK_SOCKAF(so, AF_INET6)) + in6_pcbdetach(inp); + else +#endif /* INET6 */ + in_pcbdetach(inp); + } + so->so_usecount--; + lck_mtx_unlock(inp->inpcb_mtx); + return; + } else if (inp->inp_wantcnt != WNT_STOPUSING) { + lck_mtx_unlock(inp->inpcb_mtx); + return; + } + + /* + * 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) { + /* Become a regular mutex */ + lck_mtx_convert_spin(inp->inpcb_mtx); + if (inp->inp_state != INPCB_STATE_DEAD) { +#if INET6 + if (INP_CHECK_SOCKAF(so, AF_INET6)) + in6_pcbdetach(inp); + else +#endif /* INET6 */ + in_pcbdetach(inp); + } + in_pcbdispose(inp); + } else { + lck_mtx_unlock(inp->inpcb_mtx); + } +} + +static int bg_cnt = 0; +#define BG_COUNTER_MAX 3 + void -tcp_slowtimo() +tcp_slowtimo(void) { - register struct inpcb *ip, *ipnxt; - register struct tcpcb *tp; - register int i; - int s; + struct inpcb *inp, *nxt; + struct tcpcb *tp; + struct socket *so; + int i; #if TCPDEBUG int ostate; #endif -#if KDEBUG - static int tws_checked; + +#if KDEBUG + static int tws_checked = 0; #endif + struct inpcbinfo *pcbinfo = &tcbinfo; + KERNEL_DEBUG(DBG_FNC_TCP_SLOW | DBG_FUNC_START, 0,0,0,0,0); - s = splnet(); tcp_maxidle = tcp_keepcnt * tcp_keepintvl; - ip = tcb.lh_first; - if (ip == NULL) { - splx(s); - return; - } - /* - * Search through tcb's and update active timers. - */ - for (; ip != NULL; ip = ipnxt) { - ipnxt = ip->inp_list.le_next; - tp = intotcpcb(ip); - if (tp == 0 || tp->t_state == TCPS_LISTEN) + lck_rw_lock_shared(pcbinfo->mtx); + + bg_cnt++; + + LIST_FOREACH(inp, &tcb, inp_list) { + + so = inp->inp_socket; + + if (in_pcb_checkstate(inp, WNT_ACQUIRE, 0) == WNT_STOPUSING) continue; - /* - * Bogus state when port owned by SharedIP with loopback as the - * only configured interface: BlueBox does not filters loopback - */ - if (tp->t_state == TCP_NSTATES) - continue; - for (i = 0; i < TCPT_NTIMERS; i++) { - if (tp->t_timer[i] && --tp->t_timer[i] == 0) { + tcp_lock(so, 1, 0); + + if ((in_pcb_checkstate(inp, WNT_RELEASE,1) == WNT_STOPUSING) && so->so_usecount == 1) { + tcp_unlock(so, 1, 0); + continue; + } + tp = intotcpcb(inp); + if (tp == 0 || tp->t_state == TCPS_LISTEN) { + tcp_unlock(so, 1, 0); + continue; + } + + tp = intotcpcb(inp); + + if (tp == 0 || tp->t_state == TCPS_LISTEN) + goto tpgone; + +#if TRAFFIC_MGT + if (so->so_traffic_mgt_flags & TRAFFIC_MGT_SO_BACKGROUND && + bg_cnt > BG_COUNTER_MAX) { + u_int32_t curr_recvtotal = tcpstat.tcps_rcvtotal; + u_int32_t curr_bg_recvtotal = tcpstat.tcps_bg_rcvtotal; + u_int32_t bg_recvdiff = curr_bg_recvtotal - tp->bg_recv_snapshot; + u_int32_t tot_recvdiff = curr_recvtotal - tp->tot_recv_snapshot; + u_int32_t fg_recv_change = tot_recvdiff - bg_recvdiff; + u_int32_t recv_change; + + if (!(so->so_traffic_mgt_flags & TRAFFIC_MGT_SO_BG_SUPPRESSED)) { + if (tot_recvdiff) + recv_change = (fg_recv_change * 100) / tot_recvdiff; + else + recv_change = 0; + + if (recv_change > background_io_trigger) { + so->so_traffic_mgt_flags |= TRAFFIC_MGT_SO_BG_SUPPRESSED; + } + + tp->tot_recv_snapshot = curr_recvtotal; + tp->bg_recv_snapshot = curr_bg_recvtotal; + } + else { // SUPPRESSED + // this allows for bg traffic to subside before we start measuring total traffic change + if (tot_recvdiff) + recv_change = (bg_recvdiff * 100) / tot_recvdiff; + else + recv_change = 0; + + if (recv_change < background_io_trigger) { + // Draconian for now: if there is any change at all, keep suppressed + if (!tot_recvdiff) { + so->so_traffic_mgt_flags &= ~TRAFFIC_MGT_SO_BG_SUPPRESSED; + tp->t_unacksegs = 0; + (void) tcp_output(tp); // open window + } + } + + tp->tot_recv_snapshot = curr_recvtotal; + tp->bg_recv_snapshot = curr_bg_recvtotal; + } + } +#endif /* TRAFFIC_MGT */ + + for (i = 1; i < TCPT_NTIMERS; i++) { + if (tp->t_timer[i] != 0) { + tp->t_timer[i] -= TCP_RETRANSHZ/PR_SLOWHZ; + if (tp->t_timer[i] <= 0) { #if TCPDEBUG - ostate = tp->t_state; + ostate = tp->t_state; #endif - tp = tcp_timers(tp, i); - if (tp == NULL) - goto tpgone; + + tp->t_timer[i] = 0; /* account for granularity change between tcp_now and slowtimo */ + 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 (tp->t_inpcb->inp_socket->so_options + & SO_DEBUG) + tcp_trace(TA_USER, ostate, tp, + (void *)0, + (struct tcphdr *)0, + PRU_SLOWTIMO); #endif + } } } - tp->t_rcvtime++; - tp->t_starttime++; - if (tp->t_rtttime) - tp->t_rtttime++; tpgone: - ; + tcp_unlock(so, 1, 0); } + + if (bg_cnt > 3) + bg_cnt = 0; -#if KDEBUG - tws_checked = 0; -#endif - KERNEL_DEBUG(DBG_FNC_TCP_SLOW | DBG_FUNC_NONE, tws_checked,0,0,0,0); + /* Second part of tcp_slowtimo: garbage collect socket/tcpcb + * We need to acquire the list lock exclusively to do this + */ + + if (lck_rw_lock_shared_to_exclusive(pcbinfo->mtx) == FALSE) { + if (tcp_gc_done == TRUE) { /* don't sweat it this time. cleanup was done last time */ + tcp_gc_done = FALSE; + KERNEL_DEBUG(DBG_FNC_TCP_SLOW | DBG_FUNC_END, tws_checked, cur_tw_slot,0,0,0); + return; /* Upgrade failed and lost lock - give up this time. */ + } + lck_rw_lock_exclusive(pcbinfo->mtx); /* Upgrade failed, lost lock now take it again exclusive */ + } + tcp_gc_done = TRUE; /* * Process the items in the current time-wait slot */ +#if KDEBUG + tws_checked = 0; +#endif + KERNEL_DEBUG(DBG_FNC_TCP_SLOW | DBG_FUNC_NONE, tws_checked,0,0,0,0); - for (ip = time_wait_slots[cur_tw_slot].lh_first; ip; ip = ipnxt) - { + LIST_FOREACH(inp, &time_wait_slots[cur_tw_slot], inp_list) { #if KDEBUG tws_checked++; #endif - ipnxt = ip->inp_list.le_next; - tp = intotcpcb(ip); - if (tp == NULL) { /* tp already closed, remove from list */ - LIST_REMOVE(ip, inp_list); - continue; - } + + 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; + + tp = intotcpcb(inp); + if (tp == NULL) /* tp already closed, remove from list */ + 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; @@ -327,14 +581,30 @@ tpgone: else tp->t_timer[TCPT_2MSL] = 0; - if (tp->t_timer[TCPT_2MSL] == 0) - tp = tcp_timers(tp, TCPT_2MSL); + if (tp->t_timer[TCPT_2MSL] == 0) { + + /* That pcb is ready for a close */ + tcp_free_sackholes(tp); + tp = tcp_close(tp); + } +twunlock: + tcp_unlock(inp->inp_socket, 1, 0); + } + + + LIST_FOREACH_SAFE(inp, &tcb, inp_list, nxt) { + tcp_garbage_collect(inp, 0); + } + + /* Now cleanup the time wait ones */ + LIST_FOREACH_SAFE(inp, &time_wait_slots[cur_tw_slot], inp_list, nxt) { + tcp_garbage_collect(inp, 1); } if (++cur_tw_slot >= N_TIME_WAIT_SLOTS) cur_tw_slot = 0; - tcp_now++; /* for timestamps */ - splx(s); + + lck_rw_done(pcbinfo->mtx); KERNEL_DEBUG(DBG_FNC_TCP_SLOW | DBG_FUNC_END, tws_checked, cur_tw_slot,0,0,0); } @@ -370,6 +640,7 @@ tcp_timers(tp, timer) register int rexmt; struct socket *so_tmp; struct tcptemp *t_template; + int optlen = 0; #if TCPDEBUG int ostate; @@ -379,23 +650,29 @@ tcp_timers(tp, timer) int isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV4) == 0; #endif /* INET6 */ + so_tmp = tp->t_inpcb->inp_socket; 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] = tcp_keepintvl; - add_to_time_wait(tp); + tp->t_state != TCPS_FIN_WAIT_2 && + tp->t_rcvtime < tcp_maxidle) { + tp->t_timer[TCPT_2MSL] = (u_int32_t)tcp_keepintvl; } - else + else { tp = tcp_close(tp); + return(tp); + } break; /* @@ -404,10 +681,10 @@ tcp_timers(tp, timer) * to a longer retransmit interval and retransmit one segment. */ case TCPT_REXMT: + tcp_free_sackholes(tp); if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) { tp->t_rxtshift = TCP_MAXRXTSHIFT; tcpstat.tcps_timeoutdrop++; - so_tmp = tp->t_inpcb->inp_socket; tp = tcp_drop(tp, tp->t_softerror ? tp->t_softerror : ETIMEDOUT); postevent(so_tmp, 0, EV_TIMEOUT); @@ -426,7 +703,12 @@ tcp_timers(tp, timer) */ tp->snd_cwnd_prev = tp->snd_cwnd; tp->snd_ssthresh_prev = tp->snd_ssthresh; - tp->t_badrxtwin = tcp_now + (tp->t_srtt >> (TCP_RTT_SHIFT + 1)); + 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)); } tcpstat.tcps_rexmttimeo++; if (tp->t_state == TCPS_SYN_SENT) @@ -438,14 +720,60 @@ tcp_timers(tp, timer) tp->t_timer[TCPT_REXMT] = tp->t_rxtcur; /* - * 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. + */ + + tp->t_flags &= ~TF_PMTUD; /* Disable Path MTU Discovery for now */ + tp->t_flags |= TF_BLACKHOLE; /* Record that we may have found a black hole */ + optlen = tp->t_maxopd - tp->t_maxseg; + tp->t_pmtud_saved_maxopd = tp->t_maxopd; /* Keep track of previous MSS */ + if (tp->t_maxopd > tcp_pmtud_black_hole_mss) + tp->t_maxopd = tcp_pmtud_black_hole_mss; /* Reduce the MSS to intermediary value */ + else { + tp->t_maxopd = /* use the default MSS */ +#if INET6 + isipv6 ? tcp_v6mssdflt : +#endif /* INET6 */ + tcp_mssdflt; + } + tp->t_maxseg = tp->t_maxopd - optlen; + } + /* + * 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; + } + } + } + + + /* + * 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. + */ + 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, @@ -502,14 +830,17 @@ tcp_timers(tp, timer) * growth is 2 mss. We don't allow the threshhold * to go below this.) */ - { - 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_state >= TCPS_ESTABLISHED) { + 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_bytes_acked = 0; + tp->t_dupacks = 0; + tp->t_unacksegs = 0; } + EXIT_FASTRECOVERY(tp); (void) tcp_output(tp); break; @@ -537,6 +868,7 @@ tcp_timers(tp, timer) } tcp_setpersist(tp); tp->t_force = 1; + tp->t_unacksegs = 0; (void) tcp_output(tp); tp->t_force = 0; break; @@ -551,8 +883,8 @@ tcp_timers(tp, timer) goto dropit; if ((always_keepalive || tp->t_inpcb->inp_socket->so_options & SO_KEEPALIVE) && - tp->t_state <= TCPS_CLOSING) { - if (tp->t_rcvtime >= TCP_KEEPIDLE(tp) + tcp_maxidle) + (tp->t_state <= TCPS_CLOSING || tp->t_state == TCPS_FIN_WAIT_2)) { + if (tp->t_rcvtime >= TCP_KEEPIDLE(tp) + (u_int32_t)tcp_maxidle) goto dropit; /* * Send a packet designed to force a response @@ -569,9 +901,16 @@ tcp_timers(tp, timer) tcpstat.tcps_keepprobe++; t_template = tcp_maketemplate(tp); if (t_template) { + unsigned int ifscope; + + if (tp->t_inpcb->inp_flags & INP_BOUND_IF) + ifscope = tp->t_inpcb->inp_boundif; + else + 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); + tp->rcv_nxt, tp->snd_una - 1, 0, ifscope); (void) m_free(dtom(t_template)); } tp->t_timer[TCPT_KEEP] = tcp_keepintvl; @@ -586,7 +925,6 @@ tcp_timers(tp, timer) #endif dropit: tcpstat.tcps_keepdrops++; - so_tmp = tp->t_inpcb->inp_socket; tp = tcp_drop(tp, ETIMEDOUT); postevent(so_tmp, 0, EV_TIMEOUT); break;