2005-04-17 06:20:36 +08:00
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/*
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* INET An implementation of the TCP/IP protocol suite for the LINUX
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* operating system. INET is implemented using the BSD Socket
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* interface as the means of communication with the user level.
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*
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* Implementation of the Transmission Control Protocol(TCP).
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*
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* Version: $Id: tcp_timer.c,v 1.88 2002/02/01 22:01:04 davem Exp $
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*
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2005-05-06 07:16:16 +08:00
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* Authors: Ross Biro
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2005-04-17 06:20:36 +08:00
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* Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
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* Mark Evans, <evansmp@uhura.aston.ac.uk>
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* Corey Minyard <wf-rch!minyard@relay.EU.net>
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* Florian La Roche, <flla@stud.uni-sb.de>
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* Charles Hedrick, <hedrick@klinzhai.rutgers.edu>
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* Linus Torvalds, <torvalds@cs.helsinki.fi>
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* Alan Cox, <gw4pts@gw4pts.ampr.org>
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* Matthew Dillon, <dillon@apollo.west.oic.com>
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* Arnt Gulbrandsen, <agulbra@nvg.unit.no>
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* Jorge Cwik, <jorge@laser.satlink.net>
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*/
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#include <linux/module.h>
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#include <net/tcp.h>
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int sysctl_tcp_syn_retries = TCP_SYN_RETRIES;
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int sysctl_tcp_synack_retries = TCP_SYNACK_RETRIES;
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int sysctl_tcp_keepalive_time = TCP_KEEPALIVE_TIME;
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int sysctl_tcp_keepalive_probes = TCP_KEEPALIVE_PROBES;
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int sysctl_tcp_keepalive_intvl = TCP_KEEPALIVE_INTVL;
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int sysctl_tcp_retries1 = TCP_RETR1;
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int sysctl_tcp_retries2 = TCP_RETR2;
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int sysctl_tcp_orphan_retries;
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static void tcp_write_timer(unsigned long);
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static void tcp_delack_timer(unsigned long);
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static void tcp_keepalive_timer (unsigned long data);
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#ifdef TCP_DEBUG
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const char tcp_timer_bug_msg[] = KERN_DEBUG "tcpbug: unknown timer value\n";
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EXPORT_SYMBOL(tcp_timer_bug_msg);
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#endif
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/*
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* Using different timers for retransmit, delayed acks and probes
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* We may wish use just one timer maintaining a list of expire jiffies
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* to optimize.
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*/
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void tcp_init_xmit_timers(struct sock *sk)
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{
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struct tcp_sock *tp = tcp_sk(sk);
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init_timer(&tp->retransmit_timer);
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tp->retransmit_timer.function=&tcp_write_timer;
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tp->retransmit_timer.data = (unsigned long) sk;
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tp->pending = 0;
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init_timer(&tp->delack_timer);
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tp->delack_timer.function=&tcp_delack_timer;
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tp->delack_timer.data = (unsigned long) sk;
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tp->ack.pending = 0;
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init_timer(&sk->sk_timer);
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sk->sk_timer.function = &tcp_keepalive_timer;
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sk->sk_timer.data = (unsigned long)sk;
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}
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void tcp_clear_xmit_timers(struct sock *sk)
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{
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struct tcp_sock *tp = tcp_sk(sk);
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tp->pending = 0;
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sk_stop_timer(sk, &tp->retransmit_timer);
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tp->ack.pending = 0;
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tp->ack.blocked = 0;
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sk_stop_timer(sk, &tp->delack_timer);
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sk_stop_timer(sk, &sk->sk_timer);
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}
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static void tcp_write_err(struct sock *sk)
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{
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sk->sk_err = sk->sk_err_soft ? : ETIMEDOUT;
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sk->sk_error_report(sk);
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tcp_done(sk);
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NET_INC_STATS_BH(LINUX_MIB_TCPABORTONTIMEOUT);
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}
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/* Do not allow orphaned sockets to eat all our resources.
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* This is direct violation of TCP specs, but it is required
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* to prevent DoS attacks. It is called when a retransmission timeout
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* or zero probe timeout occurs on orphaned socket.
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*
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* Criterium is still not confirmed experimentally and may change.
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* We kill the socket, if:
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* 1. If number of orphaned sockets exceeds an administratively configured
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* limit.
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* 2. If we have strong memory pressure.
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*/
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static int tcp_out_of_resources(struct sock *sk, int do_reset)
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{
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struct tcp_sock *tp = tcp_sk(sk);
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int orphans = atomic_read(&tcp_orphan_count);
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/* If peer does not open window for long time, or did not transmit
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* anything for long time, penalize it. */
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if ((s32)(tcp_time_stamp - tp->lsndtime) > 2*TCP_RTO_MAX || !do_reset)
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orphans <<= 1;
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/* If some dubious ICMP arrived, penalize even more. */
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if (sk->sk_err_soft)
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orphans <<= 1;
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if (orphans >= sysctl_tcp_max_orphans ||
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(sk->sk_wmem_queued > SOCK_MIN_SNDBUF &&
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atomic_read(&tcp_memory_allocated) > sysctl_tcp_mem[2])) {
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if (net_ratelimit())
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printk(KERN_INFO "Out of socket memory\n");
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/* Catch exceptional cases, when connection requires reset.
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* 1. Last segment was sent recently. */
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if ((s32)(tcp_time_stamp - tp->lsndtime) <= TCP_TIMEWAIT_LEN ||
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/* 2. Window is closed. */
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(!tp->snd_wnd && !tp->packets_out))
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do_reset = 1;
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if (do_reset)
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tcp_send_active_reset(sk, GFP_ATOMIC);
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tcp_done(sk);
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NET_INC_STATS_BH(LINUX_MIB_TCPABORTONMEMORY);
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return 1;
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}
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return 0;
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}
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/* Calculate maximal number or retries on an orphaned socket. */
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static int tcp_orphan_retries(struct sock *sk, int alive)
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{
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int retries = sysctl_tcp_orphan_retries; /* May be zero. */
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/* We know from an ICMP that something is wrong. */
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if (sk->sk_err_soft && !alive)
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retries = 0;
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/* However, if socket sent something recently, select some safe
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* number of retries. 8 corresponds to >100 seconds with minimal
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* RTO of 200msec. */
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if (retries == 0 && alive)
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retries = 8;
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return retries;
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}
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/* A write timeout has occurred. Process the after effects. */
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static int tcp_write_timeout(struct sock *sk)
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{
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struct tcp_sock *tp = tcp_sk(sk);
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int retry_until;
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if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) {
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if (tp->retransmits)
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dst_negative_advice(&sk->sk_dst_cache);
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retry_until = tp->syn_retries ? : sysctl_tcp_syn_retries;
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} else {
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if (tp->retransmits >= sysctl_tcp_retries1) {
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/* NOTE. draft-ietf-tcpimpl-pmtud-01.txt requires pmtu black
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hole detection. :-(
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It is place to make it. It is not made. I do not want
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to make it. It is disguisting. It does not work in any
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case. Let me to cite the same draft, which requires for
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us to implement this:
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"The one security concern raised by this memo is that ICMP black holes
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are often caused by over-zealous security administrators who block
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all ICMP messages. It is vitally important that those who design and
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deploy security systems understand the impact of strict filtering on
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upper-layer protocols. The safest web site in the world is worthless
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if most TCP implementations cannot transfer data from it. It would
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be far nicer to have all of the black holes fixed rather than fixing
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all of the TCP implementations."
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Golden words :-).
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*/
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dst_negative_advice(&sk->sk_dst_cache);
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}
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retry_until = sysctl_tcp_retries2;
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if (sock_flag(sk, SOCK_DEAD)) {
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int alive = (tp->rto < TCP_RTO_MAX);
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retry_until = tcp_orphan_retries(sk, alive);
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if (tcp_out_of_resources(sk, alive || tp->retransmits < retry_until))
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return 1;
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}
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}
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if (tp->retransmits >= retry_until) {
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/* Has it gone just too far? */
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tcp_write_err(sk);
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return 1;
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}
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return 0;
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}
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static void tcp_delack_timer(unsigned long data)
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{
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struct sock *sk = (struct sock*)data;
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struct tcp_sock *tp = tcp_sk(sk);
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bh_lock_sock(sk);
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if (sock_owned_by_user(sk)) {
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/* Try again later. */
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tp->ack.blocked = 1;
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NET_INC_STATS_BH(LINUX_MIB_DELAYEDACKLOCKED);
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sk_reset_timer(sk, &tp->delack_timer, jiffies + TCP_DELACK_MIN);
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goto out_unlock;
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}
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sk_stream_mem_reclaim(sk);
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if (sk->sk_state == TCP_CLOSE || !(tp->ack.pending & TCP_ACK_TIMER))
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goto out;
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if (time_after(tp->ack.timeout, jiffies)) {
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sk_reset_timer(sk, &tp->delack_timer, tp->ack.timeout);
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goto out;
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}
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tp->ack.pending &= ~TCP_ACK_TIMER;
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2005-07-09 05:57:23 +08:00
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if (!skb_queue_empty(&tp->ucopy.prequeue)) {
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2005-04-17 06:20:36 +08:00
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struct sk_buff *skb;
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2005-07-09 05:57:23 +08:00
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NET_INC_STATS_BH(LINUX_MIB_TCPSCHEDULERFAILED);
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2005-04-17 06:20:36 +08:00
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while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL)
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sk->sk_backlog_rcv(sk, skb);
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tp->ucopy.memory = 0;
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}
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if (tcp_ack_scheduled(tp)) {
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if (!tp->ack.pingpong) {
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/* Delayed ACK missed: inflate ATO. */
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tp->ack.ato = min(tp->ack.ato << 1, tp->rto);
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} else {
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/* Delayed ACK missed: leave pingpong mode and
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* deflate ATO.
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*/
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tp->ack.pingpong = 0;
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tp->ack.ato = TCP_ATO_MIN;
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}
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tcp_send_ack(sk);
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NET_INC_STATS_BH(LINUX_MIB_DELAYEDACKS);
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}
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TCP_CHECK_TIMER(sk);
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out:
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if (tcp_memory_pressure)
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sk_stream_mem_reclaim(sk);
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out_unlock:
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bh_unlock_sock(sk);
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sock_put(sk);
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}
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static void tcp_probe_timer(struct sock *sk)
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{
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struct tcp_sock *tp = tcp_sk(sk);
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int max_probes;
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if (tp->packets_out || !sk->sk_send_head) {
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tp->probes_out = 0;
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return;
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}
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/* *WARNING* RFC 1122 forbids this
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*
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* It doesn't AFAIK, because we kill the retransmit timer -AK
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*
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* FIXME: We ought not to do it, Solaris 2.5 actually has fixing
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* this behaviour in Solaris down as a bug fix. [AC]
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*
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* Let me to explain. probes_out is zeroed by incoming ACKs
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* even if they advertise zero window. Hence, connection is killed only
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* if we received no ACKs for normal connection timeout. It is not killed
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* only because window stays zero for some time, window may be zero
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* until armageddon and even later. We are in full accordance
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* with RFCs, only probe timer combines both retransmission timeout
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* and probe timeout in one bottle. --ANK
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*/
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max_probes = sysctl_tcp_retries2;
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if (sock_flag(sk, SOCK_DEAD)) {
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int alive = ((tp->rto<<tp->backoff) < TCP_RTO_MAX);
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max_probes = tcp_orphan_retries(sk, alive);
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if (tcp_out_of_resources(sk, alive || tp->probes_out <= max_probes))
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return;
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}
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if (tp->probes_out > max_probes) {
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tcp_write_err(sk);
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} else {
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/* Only send another probe if we didn't close things up. */
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tcp_send_probe0(sk);
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}
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}
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/*
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* The TCP retransmit timer.
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*/
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static void tcp_retransmit_timer(struct sock *sk)
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{
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struct tcp_sock *tp = tcp_sk(sk);
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if (!tp->packets_out)
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goto out;
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BUG_TRAP(!skb_queue_empty(&sk->sk_write_queue));
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if (!tp->snd_wnd && !sock_flag(sk, SOCK_DEAD) &&
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!((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))) {
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/* Receiver dastardly shrinks window. Our retransmits
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* become zero probes, but we should not timeout this
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* connection. If the socket is an orphan, time it out,
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* we cannot allow such beasts to hang infinitely.
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*/
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#ifdef TCP_DEBUG
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if (net_ratelimit()) {
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struct inet_sock *inet = inet_sk(sk);
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printk(KERN_DEBUG "TCP: Treason uncloaked! Peer %u.%u.%u.%u:%u/%u shrinks window %u:%u. Repaired.\n",
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NIPQUAD(inet->daddr), htons(inet->dport),
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inet->num, tp->snd_una, tp->snd_nxt);
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}
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#endif
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if (tcp_time_stamp - tp->rcv_tstamp > TCP_RTO_MAX) {
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tcp_write_err(sk);
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goto out;
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}
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tcp_enter_loss(sk, 0);
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tcp_retransmit_skb(sk, skb_peek(&sk->sk_write_queue));
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__sk_dst_reset(sk);
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goto out_reset_timer;
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}
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if (tcp_write_timeout(sk))
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|
|
|
goto out;
|
|
|
|
|
|
|
|
if (tp->retransmits == 0) {
|
|
|
|
if (tp->ca_state == TCP_CA_Disorder || tp->ca_state == TCP_CA_Recovery) {
|
|
|
|
if (tp->rx_opt.sack_ok) {
|
|
|
|
if (tp->ca_state == TCP_CA_Recovery)
|
|
|
|
NET_INC_STATS_BH(LINUX_MIB_TCPSACKRECOVERYFAIL);
|
|
|
|
else
|
|
|
|
NET_INC_STATS_BH(LINUX_MIB_TCPSACKFAILURES);
|
|
|
|
} else {
|
|
|
|
if (tp->ca_state == TCP_CA_Recovery)
|
|
|
|
NET_INC_STATS_BH(LINUX_MIB_TCPRENORECOVERYFAIL);
|
|
|
|
else
|
|
|
|
NET_INC_STATS_BH(LINUX_MIB_TCPRENOFAILURES);
|
|
|
|
}
|
|
|
|
} else if (tp->ca_state == TCP_CA_Loss) {
|
|
|
|
NET_INC_STATS_BH(LINUX_MIB_TCPLOSSFAILURES);
|
|
|
|
} else {
|
|
|
|
NET_INC_STATS_BH(LINUX_MIB_TCPTIMEOUTS);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
if (tcp_use_frto(sk)) {
|
|
|
|
tcp_enter_frto(sk);
|
|
|
|
} else {
|
|
|
|
tcp_enter_loss(sk, 0);
|
|
|
|
}
|
|
|
|
|
|
|
|
if (tcp_retransmit_skb(sk, skb_peek(&sk->sk_write_queue)) > 0) {
|
|
|
|
/* Retransmission failed because of local congestion,
|
|
|
|
* do not backoff.
|
|
|
|
*/
|
|
|
|
if (!tp->retransmits)
|
|
|
|
tp->retransmits=1;
|
|
|
|
tcp_reset_xmit_timer(sk, TCP_TIME_RETRANS,
|
|
|
|
min(tp->rto, TCP_RESOURCE_PROBE_INTERVAL));
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Increase the timeout each time we retransmit. Note that
|
|
|
|
* we do not increase the rtt estimate. rto is initialized
|
|
|
|
* from rtt, but increases here. Jacobson (SIGCOMM 88) suggests
|
|
|
|
* that doubling rto each time is the least we can get away with.
|
|
|
|
* In KA9Q, Karn uses this for the first few times, and then
|
|
|
|
* goes to quadratic. netBSD doubles, but only goes up to *64,
|
|
|
|
* and clamps at 1 to 64 sec afterwards. Note that 120 sec is
|
|
|
|
* defined in the protocol as the maximum possible RTT. I guess
|
|
|
|
* we'll have to use something other than TCP to talk to the
|
|
|
|
* University of Mars.
|
|
|
|
*
|
|
|
|
* PAWS allows us longer timeouts and large windows, so once
|
|
|
|
* implemented ftp to mars will work nicely. We will have to fix
|
|
|
|
* the 120 second clamps though!
|
|
|
|
*/
|
|
|
|
tp->backoff++;
|
|
|
|
tp->retransmits++;
|
|
|
|
|
|
|
|
out_reset_timer:
|
|
|
|
tp->rto = min(tp->rto << 1, TCP_RTO_MAX);
|
|
|
|
tcp_reset_xmit_timer(sk, TCP_TIME_RETRANS, tp->rto);
|
|
|
|
if (tp->retransmits > sysctl_tcp_retries1)
|
|
|
|
__sk_dst_reset(sk);
|
|
|
|
|
|
|
|
out:;
|
|
|
|
}
|
|
|
|
|
|
|
|
static void tcp_write_timer(unsigned long data)
|
|
|
|
{
|
|
|
|
struct sock *sk = (struct sock*)data;
|
|
|
|
struct tcp_sock *tp = tcp_sk(sk);
|
|
|
|
int event;
|
|
|
|
|
|
|
|
bh_lock_sock(sk);
|
|
|
|
if (sock_owned_by_user(sk)) {
|
|
|
|
/* Try again later */
|
|
|
|
sk_reset_timer(sk, &tp->retransmit_timer, jiffies + (HZ / 20));
|
|
|
|
goto out_unlock;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (sk->sk_state == TCP_CLOSE || !tp->pending)
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
if (time_after(tp->timeout, jiffies)) {
|
|
|
|
sk_reset_timer(sk, &tp->retransmit_timer, tp->timeout);
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
event = tp->pending;
|
|
|
|
tp->pending = 0;
|
|
|
|
|
|
|
|
switch (event) {
|
|
|
|
case TCP_TIME_RETRANS:
|
|
|
|
tcp_retransmit_timer(sk);
|
|
|
|
break;
|
|
|
|
case TCP_TIME_PROBE0:
|
|
|
|
tcp_probe_timer(sk);
|
|
|
|
break;
|
|
|
|
}
|
|
|
|
TCP_CHECK_TIMER(sk);
|
|
|
|
|
|
|
|
out:
|
|
|
|
sk_stream_mem_reclaim(sk);
|
|
|
|
out_unlock:
|
|
|
|
bh_unlock_sock(sk);
|
|
|
|
sock_put(sk);
|
|
|
|
}
|
|
|
|
|
|
|
|
/*
|
|
|
|
* Timer for listening sockets
|
|
|
|
*/
|
|
|
|
|
|
|
|
static void tcp_synack_timer(struct sock *sk)
|
|
|
|
{
|
|
|
|
struct tcp_sock *tp = tcp_sk(sk);
|
2005-06-19 13:48:55 +08:00
|
|
|
struct listen_sock *lopt = tp->accept_queue.listen_opt;
|
2005-04-17 06:20:36 +08:00
|
|
|
int max_retries = tp->syn_retries ? : sysctl_tcp_synack_retries;
|
|
|
|
int thresh = max_retries;
|
|
|
|
unsigned long now = jiffies;
|
2005-06-19 13:47:21 +08:00
|
|
|
struct request_sock **reqp, *req;
|
2005-04-17 06:20:36 +08:00
|
|
|
int i, budget;
|
|
|
|
|
|
|
|
if (lopt == NULL || lopt->qlen == 0)
|
|
|
|
return;
|
|
|
|
|
|
|
|
/* Normally all the openreqs are young and become mature
|
|
|
|
* (i.e. converted to established socket) for first timeout.
|
|
|
|
* If synack was not acknowledged for 3 seconds, it means
|
|
|
|
* one of the following things: synack was lost, ack was lost,
|
|
|
|
* rtt is high or nobody planned to ack (i.e. synflood).
|
|
|
|
* When server is a bit loaded, queue is populated with old
|
|
|
|
* open requests, reducing effective size of queue.
|
|
|
|
* When server is well loaded, queue size reduces to zero
|
|
|
|
* after several minutes of work. It is not synflood,
|
|
|
|
* it is normal operation. The solution is pruning
|
|
|
|
* too old entries overriding normal timeout, when
|
|
|
|
* situation becomes dangerous.
|
|
|
|
*
|
|
|
|
* Essentially, we reserve half of room for young
|
|
|
|
* embrions; and abort old ones without pity, if old
|
|
|
|
* ones are about to clog our table.
|
|
|
|
*/
|
|
|
|
if (lopt->qlen>>(lopt->max_qlen_log-1)) {
|
|
|
|
int young = (lopt->qlen_young<<1);
|
|
|
|
|
|
|
|
while (thresh > 2) {
|
|
|
|
if (lopt->qlen < young)
|
|
|
|
break;
|
|
|
|
thresh--;
|
|
|
|
young <<= 1;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
if (tp->defer_accept)
|
|
|
|
max_retries = tp->defer_accept;
|
|
|
|
|
|
|
|
budget = 2*(TCP_SYNQ_HSIZE/(TCP_TIMEOUT_INIT/TCP_SYNQ_INTERVAL));
|
|
|
|
i = lopt->clock_hand;
|
|
|
|
|
|
|
|
do {
|
|
|
|
reqp=&lopt->syn_table[i];
|
|
|
|
while ((req = *reqp) != NULL) {
|
|
|
|
if (time_after_eq(now, req->expires)) {
|
|
|
|
if ((req->retrans < thresh ||
|
[NET] Generalise TCP's struct open_request minisock infrastructure
Kept this first changeset minimal, without changing existing names to
ease peer review.
Basicaly tcp_openreq_alloc now receives the or_calltable, that in turn
has two new members:
->slab, that replaces tcp_openreq_cachep
->obj_size, to inform the size of the openreq descendant for
a specific protocol
The protocol specific fields in struct open_request were moved to a
class hierarchy, with the things that are common to all connection
oriented PF_INET protocols in struct inet_request_sock, the TCP ones
in tcp_request_sock, that is an inet_request_sock, that is an
open_request.
I.e. this uses the same approach used for the struct sock class
hierarchy, with sk_prot indicating if the protocol wants to use the
open_request infrastructure by filling in sk_prot->rsk_prot with an
or_calltable.
Results? Performance is improved and TCP v4 now uses only 64 bytes per
open request minisock, down from 96 without this patch :-)
Next changeset will rename some of the structs, fields and functions
mentioned above, struct or_calltable is way unclear, better name it
struct request_sock_ops, s/struct open_request/struct request_sock/g,
etc.
Signed-off-by: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
2005-06-19 13:46:52 +08:00
|
|
|
(inet_rsk(req)->acked && req->retrans < max_retries))
|
2005-06-19 13:47:21 +08:00
|
|
|
&& !req->rsk_ops->rtx_syn_ack(sk, req, NULL)) {
|
2005-04-17 06:20:36 +08:00
|
|
|
unsigned long timeo;
|
|
|
|
|
|
|
|
if (req->retrans++ == 0)
|
|
|
|
lopt->qlen_young--;
|
|
|
|
timeo = min((TCP_TIMEOUT_INIT << req->retrans),
|
|
|
|
TCP_RTO_MAX);
|
|
|
|
req->expires = now + timeo;
|
|
|
|
reqp = &req->dl_next;
|
|
|
|
continue;
|
|
|
|
}
|
|
|
|
|
|
|
|
/* Drop this request */
|
2005-06-19 13:47:59 +08:00
|
|
|
tcp_synq_unlink(tp, req, reqp);
|
|
|
|
reqsk_queue_removed(&tp->accept_queue, req);
|
2005-06-19 13:47:21 +08:00
|
|
|
reqsk_free(req);
|
2005-04-17 06:20:36 +08:00
|
|
|
continue;
|
|
|
|
}
|
|
|
|
reqp = &req->dl_next;
|
|
|
|
}
|
|
|
|
|
|
|
|
i = (i+1)&(TCP_SYNQ_HSIZE-1);
|
|
|
|
|
|
|
|
} while (--budget > 0);
|
|
|
|
|
|
|
|
lopt->clock_hand = i;
|
|
|
|
|
|
|
|
if (lopt->qlen)
|
|
|
|
tcp_reset_keepalive_timer(sk, TCP_SYNQ_INTERVAL);
|
|
|
|
}
|
|
|
|
|
|
|
|
void tcp_delete_keepalive_timer (struct sock *sk)
|
|
|
|
{
|
|
|
|
sk_stop_timer(sk, &sk->sk_timer);
|
|
|
|
}
|
|
|
|
|
|
|
|
void tcp_reset_keepalive_timer (struct sock *sk, unsigned long len)
|
|
|
|
{
|
|
|
|
sk_reset_timer(sk, &sk->sk_timer, jiffies + len);
|
|
|
|
}
|
|
|
|
|
|
|
|
void tcp_set_keepalive(struct sock *sk, int val)
|
|
|
|
{
|
|
|
|
if ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN))
|
|
|
|
return;
|
|
|
|
|
|
|
|
if (val && !sock_flag(sk, SOCK_KEEPOPEN))
|
|
|
|
tcp_reset_keepalive_timer(sk, keepalive_time_when(tcp_sk(sk)));
|
|
|
|
else if (!val)
|
|
|
|
tcp_delete_keepalive_timer(sk);
|
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
static void tcp_keepalive_timer (unsigned long data)
|
|
|
|
{
|
|
|
|
struct sock *sk = (struct sock *) data;
|
|
|
|
struct tcp_sock *tp = tcp_sk(sk);
|
|
|
|
__u32 elapsed;
|
|
|
|
|
|
|
|
/* Only process if socket is not in use. */
|
|
|
|
bh_lock_sock(sk);
|
|
|
|
if (sock_owned_by_user(sk)) {
|
|
|
|
/* Try again later. */
|
|
|
|
tcp_reset_keepalive_timer (sk, HZ/20);
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (sk->sk_state == TCP_LISTEN) {
|
|
|
|
tcp_synack_timer(sk);
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (sk->sk_state == TCP_FIN_WAIT2 && sock_flag(sk, SOCK_DEAD)) {
|
|
|
|
if (tp->linger2 >= 0) {
|
|
|
|
int tmo = tcp_fin_time(tp) - TCP_TIMEWAIT_LEN;
|
|
|
|
|
|
|
|
if (tmo > 0) {
|
|
|
|
tcp_time_wait(sk, TCP_FIN_WAIT2, tmo);
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
tcp_send_active_reset(sk, GFP_ATOMIC);
|
|
|
|
goto death;
|
|
|
|
}
|
|
|
|
|
|
|
|
if (!sock_flag(sk, SOCK_KEEPOPEN) || sk->sk_state == TCP_CLOSE)
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
elapsed = keepalive_time_when(tp);
|
|
|
|
|
|
|
|
/* It is alive without keepalive 8) */
|
|
|
|
if (tp->packets_out || sk->sk_send_head)
|
|
|
|
goto resched;
|
|
|
|
|
|
|
|
elapsed = tcp_time_stamp - tp->rcv_tstamp;
|
|
|
|
|
|
|
|
if (elapsed >= keepalive_time_when(tp)) {
|
|
|
|
if ((!tp->keepalive_probes && tp->probes_out >= sysctl_tcp_keepalive_probes) ||
|
|
|
|
(tp->keepalive_probes && tp->probes_out >= tp->keepalive_probes)) {
|
|
|
|
tcp_send_active_reset(sk, GFP_ATOMIC);
|
|
|
|
tcp_write_err(sk);
|
|
|
|
goto out;
|
|
|
|
}
|
|
|
|
if (tcp_write_wakeup(sk) <= 0) {
|
|
|
|
tp->probes_out++;
|
|
|
|
elapsed = keepalive_intvl_when(tp);
|
|
|
|
} else {
|
|
|
|
/* If keepalive was lost due to local congestion,
|
|
|
|
* try harder.
|
|
|
|
*/
|
|
|
|
elapsed = TCP_RESOURCE_PROBE_INTERVAL;
|
|
|
|
}
|
|
|
|
} else {
|
|
|
|
/* It is tp->rcv_tstamp + keepalive_time_when(tp) */
|
|
|
|
elapsed = keepalive_time_when(tp) - elapsed;
|
|
|
|
}
|
|
|
|
|
|
|
|
TCP_CHECK_TIMER(sk);
|
|
|
|
sk_stream_mem_reclaim(sk);
|
|
|
|
|
|
|
|
resched:
|
|
|
|
tcp_reset_keepalive_timer (sk, elapsed);
|
|
|
|
goto out;
|
|
|
|
|
|
|
|
death:
|
|
|
|
tcp_done(sk);
|
|
|
|
|
|
|
|
out:
|
|
|
|
bh_unlock_sock(sk);
|
|
|
|
sock_put(sk);
|
|
|
|
}
|
|
|
|
|
|
|
|
EXPORT_SYMBOL(tcp_clear_xmit_timers);
|
|
|
|
EXPORT_SYMBOL(tcp_delete_keepalive_timer);
|
|
|
|
EXPORT_SYMBOL(tcp_init_xmit_timers);
|
|
|
|
EXPORT_SYMBOL(tcp_reset_keepalive_timer);
|