diff options
Diffstat (limited to 'sys/netinet/tcp_timer.c')
| -rw-r--r-- | sys/netinet/tcp_timer.c | 964 |
1 files changed, 964 insertions, 0 deletions
diff --git a/sys/netinet/tcp_timer.c b/sys/netinet/tcp_timer.c new file mode 100644 index 0000000..a64e403 --- /dev/null +++ b/sys/netinet/tcp_timer.c @@ -0,0 +1,964 @@ +/*- + * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1995 + * The Regents of the University of California. All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 4. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * @(#)tcp_timer.c 8.2 (Berkeley) 5/24/95 + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include "opt_inet.h" +#include "opt_inet6.h" +#include "opt_tcpdebug.h" +#include "opt_rss.h" + +#include <sys/param.h> +#include <sys/kernel.h> +#include <sys/lock.h> +#include <sys/mbuf.h> +#include <sys/mutex.h> +#include <sys/protosw.h> +#include <sys/smp.h> +#include <sys/socket.h> +#include <sys/socketvar.h> +#include <sys/sysctl.h> +#include <sys/systm.h> + +#include <net/if.h> +#include <net/route.h> +#include <net/rss_config.h> +#include <net/vnet.h> +#include <net/netisr.h> + +#include <netinet/cc.h> +#include <netinet/in.h> +#include <netinet/in_pcb.h> +#include <netinet/in_rss.h> +#include <netinet/in_systm.h> +#ifdef INET6 +#include <netinet6/in6_pcb.h> +#endif +#include <netinet/ip_var.h> +#include <netinet/tcp_fsm.h> +#include <netinet/tcp_timer.h> +#include <netinet/tcp_var.h> +#ifdef INET6 +#include <netinet6/tcp6_var.h> +#endif +#include <netinet/tcpip.h> +#ifdef TCPDEBUG +#include <netinet/tcp_debug.h> +#endif + +int tcp_keepinit; +SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINIT, keepinit, CTLTYPE_INT|CTLFLAG_RW, + &tcp_keepinit, 0, sysctl_msec_to_ticks, "I", "time to establish connection"); + +int tcp_keepidle; +SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPIDLE, keepidle, CTLTYPE_INT|CTLFLAG_RW, + &tcp_keepidle, 0, sysctl_msec_to_ticks, "I", "time before keepalive probes begin"); + +int tcp_keepintvl; +SYSCTL_PROC(_net_inet_tcp, TCPCTL_KEEPINTVL, keepintvl, CTLTYPE_INT|CTLFLAG_RW, + &tcp_keepintvl, 0, sysctl_msec_to_ticks, "I", "time between keepalive probes"); + +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"); + +int tcp_rexmit_min; +SYSCTL_PROC(_net_inet_tcp, OID_AUTO, rexmit_min, CTLTYPE_INT|CTLFLAG_RW, + &tcp_rexmit_min, 0, sysctl_msec_to_ticks, "I", + "Minimum Retransmission Timeout"); + +int tcp_rexmit_slop; +SYSCTL_PROC(_net_inet_tcp, OID_AUTO, rexmit_slop, CTLTYPE_INT|CTLFLAG_RW, + &tcp_rexmit_slop, 0, sysctl_msec_to_ticks, "I", + "Retransmission Timer Slop"); + +static int always_keepalive = 1; +SYSCTL_INT(_net_inet_tcp, OID_AUTO, always_keepalive, CTLFLAG_RW, + &always_keepalive , 0, "Assume SO_KEEPALIVE on all TCP connections"); + +int tcp_fast_finwait2_recycle = 0; +SYSCTL_INT(_net_inet_tcp, OID_AUTO, fast_finwait2_recycle, CTLFLAG_RW, + &tcp_fast_finwait2_recycle, 0, + "Recycle closed FIN_WAIT_2 connections faster"); + +int tcp_finwait2_timeout; +SYSCTL_PROC(_net_inet_tcp, OID_AUTO, finwait2_timeout, CTLTYPE_INT|CTLFLAG_RW, + &tcp_finwait2_timeout, 0, sysctl_msec_to_ticks, "I", "FIN-WAIT2 timeout"); + +int tcp_keepcnt = TCPTV_KEEPCNT; +SYSCTL_INT(_net_inet_tcp, OID_AUTO, keepcnt, CTLFLAG_RW, &tcp_keepcnt, 0, + "Number of keepalive probes to send"); + + /* max idle probes */ +int tcp_maxpersistidle; + +static int tcp_rexmit_drop_options = 0; +SYSCTL_INT(_net_inet_tcp, OID_AUTO, rexmit_drop_options, CTLFLAG_RW, + &tcp_rexmit_drop_options, 0, + "Drop TCP options from 3rd and later retransmitted SYN"); + +static VNET_DEFINE(int, tcp_pmtud_blackhole_detect); +#define V_tcp_pmtud_blackhole_detect VNET(tcp_pmtud_blackhole_detect) +SYSCTL_INT(_net_inet_tcp, OID_AUTO, pmtud_blackhole_detection, + CTLFLAG_RW|CTLFLAG_VNET, + &VNET_NAME(tcp_pmtud_blackhole_detect), 0, + "Path MTU Discovery Black Hole Detection Enabled"); + +static VNET_DEFINE(int, tcp_pmtud_blackhole_activated); +#define V_tcp_pmtud_blackhole_activated \ + VNET(tcp_pmtud_blackhole_activated) +SYSCTL_INT(_net_inet_tcp, OID_AUTO, pmtud_blackhole_activated, + CTLFLAG_RD|CTLFLAG_VNET, + &VNET_NAME(tcp_pmtud_blackhole_activated), 0, + "Path MTU Discovery Black Hole Detection, Activation Count"); + +static VNET_DEFINE(int, tcp_pmtud_blackhole_activated_min_mss); +#define V_tcp_pmtud_blackhole_activated_min_mss \ + VNET(tcp_pmtud_blackhole_activated_min_mss) +SYSCTL_INT(_net_inet_tcp, OID_AUTO, pmtud_blackhole_activated_min_mss, + CTLFLAG_RD|CTLFLAG_VNET, + &VNET_NAME(tcp_pmtud_blackhole_activated_min_mss), 0, + "Path MTU Discovery Black Hole Detection, Activation Count at min MSS"); + +static VNET_DEFINE(int, tcp_pmtud_blackhole_failed); +#define V_tcp_pmtud_blackhole_failed VNET(tcp_pmtud_blackhole_failed) +SYSCTL_INT(_net_inet_tcp, OID_AUTO, pmtud_blackhole_failed, + CTLFLAG_RD|CTLFLAG_VNET, + &VNET_NAME(tcp_pmtud_blackhole_failed), 0, + "Path MTU Discovery Black Hole Detection, Failure Count"); + +#ifdef INET +static VNET_DEFINE(int, tcp_pmtud_blackhole_mss) = 1200; +#define V_tcp_pmtud_blackhole_mss VNET(tcp_pmtud_blackhole_mss) +SYSCTL_INT(_net_inet_tcp, OID_AUTO, pmtud_blackhole_mss, + CTLFLAG_RW|CTLFLAG_VNET, + &VNET_NAME(tcp_pmtud_blackhole_mss), 0, + "Path MTU Discovery Black Hole Detection lowered MSS"); +#endif + +#ifdef INET6 +static VNET_DEFINE(int, tcp_v6pmtud_blackhole_mss) = 1220; +#define V_tcp_v6pmtud_blackhole_mss VNET(tcp_v6pmtud_blackhole_mss) +SYSCTL_INT(_net_inet_tcp, OID_AUTO, v6pmtud_blackhole_mss, + CTLFLAG_RW|CTLFLAG_VNET, + &VNET_NAME(tcp_v6pmtud_blackhole_mss), 0, + "Path MTU Discovery IPv6 Black Hole Detection lowered MSS"); +#endif + +#ifdef RSS +static int per_cpu_timers = 1; +#else +static int per_cpu_timers = 0; +#endif +SYSCTL_INT(_net_inet_tcp, OID_AUTO, per_cpu_timers, CTLFLAG_RW, + &per_cpu_timers , 0, "run tcp timers on all cpus"); + +#if 0 +#define INP_CPU(inp) (per_cpu_timers ? (!CPU_ABSENT(((inp)->inp_flowid % (mp_maxid+1))) ? \ + ((inp)->inp_flowid % (mp_maxid+1)) : curcpu) : 0) +#endif + +/* + * Map the given inp to a CPU id. + * + * This queries RSS if it's compiled in, else it defaults to the current + * CPU ID. + */ +static inline int +inp_to_cpuid(struct inpcb *inp) +{ + u_int cpuid; + +#ifdef RSS + if (per_cpu_timers) { + cpuid = rss_hash2cpuid(inp->inp_flowid, inp->inp_flowtype); + if (cpuid == NETISR_CPUID_NONE) + return (curcpu); /* XXX */ + else + return (cpuid); + } +#else + /* Legacy, pre-RSS behaviour */ + if (per_cpu_timers) { + /* + * We don't have a flowid -> cpuid mapping, so cheat and + * just map unknown cpuids to curcpu. Not the best, but + * apparently better than defaulting to swi 0. + */ + cpuid = inp->inp_flowid % (mp_maxid + 1); + if (! CPU_ABSENT(cpuid)) + return (cpuid); + return (curcpu); + } +#endif + /* Default for RSS and non-RSS - cpuid 0 */ + else { + return (0); + } +} + +/* + * Tcp protocol timeout routine called every 500 ms. + * Updates timestamps used for TCP + * causes finite state machine actions if timers expire. + */ +void +tcp_slowtimo(void) +{ + VNET_ITERATOR_DECL(vnet_iter); + + VNET_LIST_RLOCK_NOSLEEP(); + VNET_FOREACH(vnet_iter) { + CURVNET_SET(vnet_iter); + (void) tcp_tw_2msl_scan(0); + CURVNET_RESTORE(); + } + VNET_LIST_RUNLOCK_NOSLEEP(); +} + +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, 128, 256, 512, 512, 512, 512 }; + +static int tcp_totbackoff = 2559; /* sum of tcp_backoff[] */ + +/* + * TCP timer processing. + */ + +void +tcp_timer_delack(void *xtp) +{ + struct tcpcb *tp = xtp; + struct inpcb *inp; + CURVNET_SET(tp->t_vnet); + + inp = tp->t_inpcb; + KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp)); + INP_WLOCK(inp); + if (callout_pending(&tp->t_timers->tt_delack) || + !callout_active(&tp->t_timers->tt_delack)) { + INP_WUNLOCK(inp); + CURVNET_RESTORE(); + return; + } + callout_deactivate(&tp->t_timers->tt_delack); + if ((inp->inp_flags & INP_DROPPED) != 0) { + INP_WUNLOCK(inp); + CURVNET_RESTORE(); + return; + } + KASSERT((tp->t_timers->tt_flags & TT_STOPPED) == 0, + ("%s: tp %p tcpcb can't be stopped here", __func__, tp)); + KASSERT((tp->t_timers->tt_flags & TT_DELACK) != 0, + ("%s: tp %p delack callout should be running", __func__, tp)); + + tp->t_flags |= TF_ACKNOW; + TCPSTAT_INC(tcps_delack); + (void) tcp_output(tp); + INP_WUNLOCK(inp); + CURVNET_RESTORE(); +} + +void +tcp_timer_2msl(void *xtp) +{ + struct tcpcb *tp = xtp; + struct inpcb *inp; + CURVNET_SET(tp->t_vnet); +#ifdef TCPDEBUG + int ostate; + + ostate = tp->t_state; +#endif + INP_INFO_WLOCK(&V_tcbinfo); + inp = tp->t_inpcb; + KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp)); + INP_WLOCK(inp); + tcp_free_sackholes(tp); + if (callout_pending(&tp->t_timers->tt_2msl) || + !callout_active(&tp->t_timers->tt_2msl)) { + INP_WUNLOCK(tp->t_inpcb); + INP_INFO_WUNLOCK(&V_tcbinfo); + CURVNET_RESTORE(); + return; + } + callout_deactivate(&tp->t_timers->tt_2msl); + if ((inp->inp_flags & INP_DROPPED) != 0) { + INP_WUNLOCK(inp); + INP_INFO_WUNLOCK(&V_tcbinfo); + CURVNET_RESTORE(); + return; + } + KASSERT((tp->t_timers->tt_flags & TT_STOPPED) == 0, + ("%s: tp %p tcpcb can't be stopped here", __func__, tp)); + KASSERT((tp->t_timers->tt_flags & TT_2MSL) != 0, + ("%s: tp %p 2msl callout should be running", __func__, tp)); + /* + * 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. + * + * If fastrecycle of FIN_WAIT_2, in FIN_WAIT_2 and receiver has closed, + * there's no point in hanging onto FIN_WAIT_2 socket. Just close it. + * Ignore fact that there were recent incoming segments. + */ + if (tcp_fast_finwait2_recycle && tp->t_state == TCPS_FIN_WAIT_2 && + tp->t_inpcb && tp->t_inpcb->inp_socket && + (tp->t_inpcb->inp_socket->so_rcv.sb_state & SBS_CANTRCVMORE)) { + TCPSTAT_INC(tcps_finwait2_drops); + tp = tcp_close(tp); + } else { + if (tp->t_state != TCPS_TIME_WAIT && + ticks - tp->t_rcvtime <= TP_MAXIDLE(tp)) + callout_reset_on(&tp->t_timers->tt_2msl, + TP_KEEPINTVL(tp), tcp_timer_2msl, tp, + inp_to_cpuid(inp)); + else + tp = tcp_close(tp); + } + +#ifdef TCPDEBUG + if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) + tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0, + PRU_SLOWTIMO); +#endif + if (tp != NULL) + INP_WUNLOCK(inp); + INP_INFO_WUNLOCK(&V_tcbinfo); + CURVNET_RESTORE(); +} + +void +tcp_timer_keep(void *xtp) +{ + struct tcpcb *tp = xtp; + struct tcptemp *t_template; + struct inpcb *inp; + CURVNET_SET(tp->t_vnet); +#ifdef TCPDEBUG + int ostate; + + ostate = tp->t_state; +#endif + INP_INFO_WLOCK(&V_tcbinfo); + inp = tp->t_inpcb; + KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp)); + INP_WLOCK(inp); + if (callout_pending(&tp->t_timers->tt_keep) || + !callout_active(&tp->t_timers->tt_keep)) { + INP_WUNLOCK(inp); + INP_INFO_WUNLOCK(&V_tcbinfo); + CURVNET_RESTORE(); + return; + } + callout_deactivate(&tp->t_timers->tt_keep); + if ((inp->inp_flags & INP_DROPPED) != 0) { + INP_WUNLOCK(inp); + INP_INFO_WUNLOCK(&V_tcbinfo); + CURVNET_RESTORE(); + return; + } + KASSERT((tp->t_timers->tt_flags & TT_STOPPED) == 0, + ("%s: tp %p tcpcb can't be stopped here", __func__, tp)); + KASSERT((tp->t_timers->tt_flags & TT_KEEP) != 0, + ("%s: tp %p keep callout should be running", __func__, tp)); + /* + * Keep-alive timer went off; send something + * or drop connection if idle for too long. + */ + TCPSTAT_INC(tcps_keeptimeo); + if (tp->t_state < TCPS_ESTABLISHED) + goto dropit; + if ((always_keepalive || inp->inp_socket->so_options & SO_KEEPALIVE) && + tp->t_state <= TCPS_CLOSING) { + if (ticks - tp->t_rcvtime >= TP_KEEPIDLE(tp) + TP_MAXIDLE(tp)) + goto dropit; + /* + * Send a packet designed to force a response + * if the peer is up and reachable: + * either an ACK if the connection is still alive, + * or an RST if the peer has closed the connection + * due to timeout or reboot. + * Using sequence number tp->snd_una-1 + * causes the transmitted zero-length segment + * to lie outside the receive window; + * by the protocol spec, this requires the + * correspondent TCP to respond. + */ + TCPSTAT_INC(tcps_keepprobe); + t_template = tcpip_maketemplate(inp); + if (t_template) { + tcp_respond(tp, t_template->tt_ipgen, + &t_template->tt_t, (struct mbuf *)NULL, + tp->rcv_nxt, tp->snd_una - 1, 0); + free(t_template, M_TEMP); + } + callout_reset_on(&tp->t_timers->tt_keep, TP_KEEPINTVL(tp), + tcp_timer_keep, tp, inp_to_cpuid(inp)); + } else + callout_reset_on(&tp->t_timers->tt_keep, TP_KEEPIDLE(tp), + tcp_timer_keep, tp, inp_to_cpuid(inp)); + +#ifdef TCPDEBUG + if (inp->inp_socket->so_options & SO_DEBUG) + tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0, + PRU_SLOWTIMO); +#endif + INP_WUNLOCK(inp); + INP_INFO_WUNLOCK(&V_tcbinfo); + CURVNET_RESTORE(); + return; + +dropit: + TCPSTAT_INC(tcps_keepdrops); + tp = tcp_drop(tp, ETIMEDOUT); + +#ifdef TCPDEBUG + if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) + tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0, + PRU_SLOWTIMO); +#endif + if (tp != NULL) + INP_WUNLOCK(tp->t_inpcb); + INP_INFO_WUNLOCK(&V_tcbinfo); + CURVNET_RESTORE(); +} + +void +tcp_timer_persist(void *xtp) +{ + struct tcpcb *tp = xtp; + struct inpcb *inp; + CURVNET_SET(tp->t_vnet); +#ifdef TCPDEBUG + int ostate; + + ostate = tp->t_state; +#endif + INP_INFO_WLOCK(&V_tcbinfo); + inp = tp->t_inpcb; + KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp)); + INP_WLOCK(inp); + if (callout_pending(&tp->t_timers->tt_persist) || + !callout_active(&tp->t_timers->tt_persist)) { + INP_WUNLOCK(inp); + INP_INFO_WUNLOCK(&V_tcbinfo); + CURVNET_RESTORE(); + return; + } + callout_deactivate(&tp->t_timers->tt_persist); + if ((inp->inp_flags & INP_DROPPED) != 0) { + INP_WUNLOCK(inp); + INP_INFO_WUNLOCK(&V_tcbinfo); + CURVNET_RESTORE(); + return; + } + KASSERT((tp->t_timers->tt_flags & TT_STOPPED) == 0, + ("%s: tp %p tcpcb can't be stopped here", __func__, tp)); + KASSERT((tp->t_timers->tt_flags & TT_PERSIST) != 0, + ("%s: tp %p persist callout should be running", __func__, tp)); + /* + * Persistance timer into zero window. + * Force a byte to be output, if possible. + */ + TCPSTAT_INC(tcps_persisttimeo); + /* + * Hack: if the peer is dead/unreachable, we do not + * time out if the window is closed. After a full + * backoff, drop the connection if the idle time + * (no responses to probes) reaches the maximum + * backoff that we would use if retransmitting. + */ + if (tp->t_rxtshift == TCP_MAXRXTSHIFT && + (ticks - tp->t_rcvtime >= tcp_maxpersistidle || + ticks - tp->t_rcvtime >= TCP_REXMTVAL(tp) * tcp_totbackoff)) { + TCPSTAT_INC(tcps_persistdrop); + tp = tcp_drop(tp, ETIMEDOUT); + goto out; + } + /* + * If the user has closed the socket then drop a persisting + * connection after a much reduced timeout. + */ + if (tp->t_state > TCPS_CLOSE_WAIT && + (ticks - tp->t_rcvtime) >= TCPTV_PERSMAX) { + TCPSTAT_INC(tcps_persistdrop); + tp = tcp_drop(tp, ETIMEDOUT); + goto out; + } + tcp_setpersist(tp); + tp->t_flags |= TF_FORCEDATA; + (void) tcp_output(tp); + tp->t_flags &= ~TF_FORCEDATA; + +out: +#ifdef TCPDEBUG + if (tp != NULL && tp->t_inpcb->inp_socket->so_options & SO_DEBUG) + tcp_trace(TA_USER, ostate, tp, NULL, NULL, PRU_SLOWTIMO); +#endif + if (tp != NULL) + INP_WUNLOCK(inp); + INP_INFO_WUNLOCK(&V_tcbinfo); + CURVNET_RESTORE(); +} + +void +tcp_timer_rexmt(void * xtp) +{ + struct tcpcb *tp = xtp; + CURVNET_SET(tp->t_vnet); + int rexmt; + int headlocked; + struct inpcb *inp; +#ifdef TCPDEBUG + int ostate; + + ostate = tp->t_state; +#endif + + INP_INFO_RLOCK(&V_tcbinfo); + inp = tp->t_inpcb; + KASSERT(inp != NULL, ("%s: tp %p tp->t_inpcb == NULL", __func__, tp)); + INP_WLOCK(inp); + if (callout_pending(&tp->t_timers->tt_rexmt) || + !callout_active(&tp->t_timers->tt_rexmt)) { + INP_WUNLOCK(inp); + INP_INFO_RUNLOCK(&V_tcbinfo); + CURVNET_RESTORE(); + return; + } + callout_deactivate(&tp->t_timers->tt_rexmt); + if ((inp->inp_flags & INP_DROPPED) != 0) { + INP_WUNLOCK(inp); + INP_INFO_RUNLOCK(&V_tcbinfo); + CURVNET_RESTORE(); + return; + } + KASSERT((tp->t_timers->tt_flags & TT_STOPPED) == 0, + ("%s: tp %p tcpcb can't be stopped here", __func__, tp)); + KASSERT((tp->t_timers->tt_flags & TT_REXMT) != 0, + ("%s: tp %p rexmt callout should be running", __func__, tp)); + tcp_free_sackholes(tp); + /* + * Retransmission timer went off. Message has not + * been acked within retransmit interval. Back off + * to a longer retransmit interval and retransmit one segment. + */ + if (++tp->t_rxtshift > TCP_MAXRXTSHIFT) { + tp->t_rxtshift = TCP_MAXRXTSHIFT; + TCPSTAT_INC(tcps_timeoutdrop); + in_pcbref(inp); + INP_INFO_RUNLOCK(&V_tcbinfo); + INP_WUNLOCK(inp); + INP_INFO_WLOCK(&V_tcbinfo); + INP_WLOCK(inp); + if (in_pcbrele_wlocked(inp)) { + INP_INFO_WUNLOCK(&V_tcbinfo); + CURVNET_RESTORE(); + return; + } + if (inp->inp_flags & INP_DROPPED) { + INP_WUNLOCK(inp); + INP_INFO_WUNLOCK(&V_tcbinfo); + CURVNET_RESTORE(); + return; + } + + tp = tcp_drop(tp, tp->t_softerror ? + tp->t_softerror : ETIMEDOUT); + headlocked = 1; + goto out; + } + INP_INFO_RUNLOCK(&V_tcbinfo); + headlocked = 0; + if (tp->t_state == TCPS_SYN_SENT) { + /* + * If the SYN was retransmitted, indicate CWND to be + * limited to 1 segment in cc_conn_init(). + */ + tp->snd_cwnd = 1; + } else 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->t_flags)) + tp->t_flags |= TF_WASFRECOVERY; + else + tp->t_flags &= ~TF_WASFRECOVERY; + if (IN_CONGRECOVERY(tp->t_flags)) + tp->t_flags |= TF_WASCRECOVERY; + else + tp->t_flags &= ~TF_WASCRECOVERY; + tp->t_badrxtwin = ticks + (tp->t_srtt >> (TCP_RTT_SHIFT + 1)); + tp->t_flags |= TF_PREVVALID; + } else + tp->t_flags &= ~TF_PREVVALID; + TCPSTAT_INC(tcps_rexmttimeo); + if (tp->t_state == TCPS_SYN_SENT) + rexmt = TCPTV_RTOBASE * tcp_syn_backoff[tp->t_rxtshift]; + else + rexmt = TCP_REXMTVAL(tp) * tcp_backoff[tp->t_rxtshift]; + TCPT_RANGESET(tp->t_rxtcur, rexmt, + tp->t_rttmin, TCPTV_REXMTMAX); + + /* + * We enter the path for PLMTUD if connection is established or, if + * connection is FIN_WAIT_1 status, reason for the last is that if + * amount of data we send is very small, we could send it in couple of + * packets and process straight to FIN. In that case we won't catch + * ESTABLISHED state. + */ + if (V_tcp_pmtud_blackhole_detect && (((tp->t_state == TCPS_ESTABLISHED)) + || (tp->t_state == TCPS_FIN_WAIT_1))) { + int optlen; +#ifdef INET6 + int isipv6; +#endif + + if (((tp->t_flags2 & (TF2_PLPMTU_PMTUD|TF2_PLPMTU_MAXSEGSNT)) == + (TF2_PLPMTU_PMTUD|TF2_PLPMTU_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 + * negotiated with peer. + */ + /* Record that we may have found a black hole. */ + tp->t_flags2 |= TF2_PLPMTU_BLACKHOLE; + + /* Keep track of previous MSS. */ + optlen = tp->t_maxopd - tp->t_maxseg; + tp->t_pmtud_saved_maxopd = tp->t_maxopd; + + /* + * Reduce the MSS to blackhole value or to the default + * in an attempt to retransmit. + */ +#ifdef INET6 + isipv6 = (tp->t_inpcb->inp_vflag & INP_IPV6) ? 1 : 0; + if (isipv6 && + tp->t_maxopd > V_tcp_v6pmtud_blackhole_mss) { + /* Use the sysctl tuneable blackhole MSS. */ + tp->t_maxopd = V_tcp_v6pmtud_blackhole_mss; + V_tcp_pmtud_blackhole_activated++; + } else if (isipv6) { + /* Use the default MSS. */ + tp->t_maxopd = V_tcp_v6mssdflt; + /* + * Disable Path MTU Discovery when we switch to + * minmss. + */ + tp->t_flags2 &= ~TF2_PLPMTU_PMTUD; + V_tcp_pmtud_blackhole_activated_min_mss++; + } +#endif +#if defined(INET6) && defined(INET) + else +#endif +#ifdef INET + if (tp->t_maxopd > V_tcp_pmtud_blackhole_mss) { + /* Use the sysctl tuneable blackhole MSS. */ + tp->t_maxopd = V_tcp_pmtud_blackhole_mss; + V_tcp_pmtud_blackhole_activated++; + } else { + /* Use the default MSS. */ + tp->t_maxopd = V_tcp_mssdflt; + /* + * Disable Path MTU Discovery when we switch to + * minmss. + */ + tp->t_flags2 &= ~TF2_PLPMTU_PMTUD; + V_tcp_pmtud_blackhole_activated_min_mss++; + } +#endif + 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)->conn_init != NULL) + CC_ALGO(tp)->conn_init(tp->ccv); + } else { + /* + * If further retransmissions are still unsuccessful + * with a lowered MTU, maybe this isn't a blackhole and + * we restore the previous MSS and blackhole detection + * flags. + */ + if ((tp->t_flags2 & TF2_PLPMTU_BLACKHOLE) && + (tp->t_rxtshift > 4)) { + tp->t_flags2 |= TF2_PLPMTU_PMTUD; + tp->t_flags2 &= ~TF2_PLPMTU_BLACKHOLE; + optlen = tp->t_maxopd - tp->t_maxseg; + tp->t_maxopd = tp->t_pmtud_saved_maxopd; + tp->t_maxseg = tp->t_maxopd - optlen; + V_tcp_pmtud_blackhole_failed++; + /* + * Reset the slow-start flight size as it + * may depend on the new MSS. + */ + if (CC_ALGO(tp)->conn_init != NULL) + CC_ALGO(tp)->conn_init(tp->ccv); + } + } + } + + /* + * Disable RFC1323 and SACK if we haven'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. + */ + if (tcp_rexmit_drop_options && (tp->t_state == TCPS_SYN_SENT) && + (tp->t_rxtshift == 3)) + tp->t_flags &= ~(TF_REQ_SCALE|TF_REQ_TSTMP|TF_SACK_PERMIT); + /* + * If we backed off this far, our srtt estimate is probably bogus. + * Clobber it so we'll take the next rtt measurement as our srtt; + * move the current srtt into rttvar to keep the current + * retransmit times until then. + */ + if (tp->t_rxtshift > TCP_MAXRXTSHIFT / 4) { +#ifdef INET6 + if ((tp->t_inpcb->inp_vflag & INP_IPV6) != 0) + in6_losing(tp->t_inpcb); +#endif + tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT); + tp->t_srtt = 0; + } + tp->snd_nxt = tp->snd_una; + tp->snd_recover = tp->snd_max; + /* + * Force a segment to be sent. + */ + tp->t_flags |= TF_ACKNOW; + /* + * If timing a segment in this window, stop the timer. + */ + tp->t_rtttime = 0; + + cc_cong_signal(tp, NULL, CC_RTO); + + (void) tcp_output(tp); + +out: +#ifdef TCPDEBUG + if (tp != NULL && (tp->t_inpcb->inp_socket->so_options & SO_DEBUG)) + tcp_trace(TA_USER, ostate, tp, (void *)0, (struct tcphdr *)0, + PRU_SLOWTIMO); +#endif + if (tp != NULL) + INP_WUNLOCK(inp); + if (headlocked) + INP_INFO_WUNLOCK(&V_tcbinfo); + CURVNET_RESTORE(); +} + +void +tcp_timer_activate(struct tcpcb *tp, uint32_t timer_type, u_int delta) +{ + struct callout *t_callout; + timeout_t *f_callout; + struct inpcb *inp = tp->t_inpcb; + int cpu = inp_to_cpuid(inp); + +#ifdef TCP_OFFLOAD + if (tp->t_flags & TF_TOE) + return; +#endif + + if (tp->t_timers->tt_flags & TT_STOPPED) + return; + + switch (timer_type) { + case TT_DELACK: + t_callout = &tp->t_timers->tt_delack; + f_callout = tcp_timer_delack; + break; + case TT_REXMT: + t_callout = &tp->t_timers->tt_rexmt; + f_callout = tcp_timer_rexmt; + break; + case TT_PERSIST: + t_callout = &tp->t_timers->tt_persist; + f_callout = tcp_timer_persist; + break; + case TT_KEEP: + t_callout = &tp->t_timers->tt_keep; + f_callout = tcp_timer_keep; + break; + case TT_2MSL: + t_callout = &tp->t_timers->tt_2msl; + f_callout = tcp_timer_2msl; + break; + default: + panic("tp %p bad timer_type %#x", tp, timer_type); + } + if (delta == 0) { + if ((tp->t_timers->tt_flags & timer_type) && + callout_stop(t_callout)) { + tp->t_timers->tt_flags &= ~timer_type; + } + } else { + if ((tp->t_timers->tt_flags & timer_type) == 0) { + tp->t_timers->tt_flags |= timer_type; + callout_reset_on(t_callout, delta, f_callout, tp, cpu); + } else { + /* Reset already running callout on the same CPU. */ + callout_reset(t_callout, delta, f_callout, tp); + } + } +} + +int +tcp_timer_active(struct tcpcb *tp, uint32_t timer_type) +{ + struct callout *t_callout; + + switch (timer_type) { + case TT_DELACK: + t_callout = &tp->t_timers->tt_delack; + break; + case TT_REXMT: + t_callout = &tp->t_timers->tt_rexmt; + break; + case TT_PERSIST: + t_callout = &tp->t_timers->tt_persist; + break; + case TT_KEEP: + t_callout = &tp->t_timers->tt_keep; + break; + case TT_2MSL: + t_callout = &tp->t_timers->tt_2msl; + break; + default: + panic("tp %p bad timer_type %#x", tp, timer_type); + } + return callout_active(t_callout); +} + +void +tcp_timer_stop(struct tcpcb *tp, uint32_t timer_type) +{ + struct callout *t_callout; + timeout_t *f_callout; + + tp->t_timers->tt_flags |= TT_STOPPED; + + switch (timer_type) { + case TT_DELACK: + t_callout = &tp->t_timers->tt_delack; + f_callout = tcp_timer_delack_discard; + break; + case TT_REXMT: + t_callout = &tp->t_timers->tt_rexmt; + f_callout = tcp_timer_rexmt_discard; + break; + case TT_PERSIST: + t_callout = &tp->t_timers->tt_persist; + f_callout = tcp_timer_persist_discard; + break; + case TT_KEEP: + t_callout = &tp->t_timers->tt_keep; + f_callout = tcp_timer_keep_discard; + break; + case TT_2MSL: + t_callout = &tp->t_timers->tt_2msl; + f_callout = tcp_timer_2msl_discard; + break; + default: + panic("tp %p bad timer_type %#x", tp, timer_type); + } + + if (tp->t_timers->tt_flags & timer_type) { + if (callout_stop(t_callout)) { + tp->t_timers->tt_flags &= ~timer_type; + } else { + /* + * Can't stop the callout, defer tcpcb actual deletion + * to the last tcp timer discard callout. + * The TT_STOPPED flag will ensure that no tcp timer + * callouts can be restarted on our behalf, and + * past this point currently running callouts waiting + * on inp lock will return right away after the + * classical check for callout reset/stop events: + * callout_pending() || !callout_active() + */ + callout_reset(t_callout, 1, f_callout, tp); + } + } +} + +#define ticks_to_msecs(t) (1000*(t) / hz) + +void +tcp_timer_to_xtimer(struct tcpcb *tp, struct tcp_timer *timer, + struct xtcp_timer *xtimer) +{ + sbintime_t now; + + bzero(xtimer, sizeof(*xtimer)); + if (timer == NULL) + return; + now = getsbinuptime(); + if (callout_active(&timer->tt_delack)) + xtimer->tt_delack = (timer->tt_delack.c_time - now) / SBT_1MS; + if (callout_active(&timer->tt_rexmt)) + xtimer->tt_rexmt = (timer->tt_rexmt.c_time - now) / SBT_1MS; + if (callout_active(&timer->tt_persist)) + xtimer->tt_persist = (timer->tt_persist.c_time - now) / SBT_1MS; + if (callout_active(&timer->tt_keep)) + xtimer->tt_keep = (timer->tt_keep.c_time - now) / SBT_1MS; + if (callout_active(&timer->tt_2msl)) + xtimer->tt_2msl = (timer->tt_2msl.c_time - now) / SBT_1MS; + xtimer->t_rcvtime = ticks_to_msecs(ticks - tp->t_rcvtime); +} |
