Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * INET An implementation of the TCP/IP protocol suite for the LINUX |
| 3 | * operating system. INET is implemented using the BSD Socket |
| 4 | * interface as the means of communication with the user level. |
| 5 | * |
| 6 | * Implementation of the Transmission Control Protocol(TCP). |
| 7 | * |
Jesper Juhl | 02c30a8 | 2005-05-05 16:16:16 -0700 | [diff] [blame] | 8 | * Authors: Ross Biro |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 9 | * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> |
| 10 | * Mark Evans, <evansmp@uhura.aston.ac.uk> |
| 11 | * Corey Minyard <wf-rch!minyard@relay.EU.net> |
| 12 | * Florian La Roche, <flla@stud.uni-sb.de> |
| 13 | * Charles Hedrick, <hedrick@klinzhai.rutgers.edu> |
| 14 | * Linus Torvalds, <torvalds@cs.helsinki.fi> |
| 15 | * Alan Cox, <gw4pts@gw4pts.ampr.org> |
| 16 | * Matthew Dillon, <dillon@apollo.west.oic.com> |
| 17 | * Arnt Gulbrandsen, <agulbra@nvg.unit.no> |
| 18 | * Jorge Cwik, <jorge@laser.satlink.net> |
| 19 | */ |
| 20 | |
| 21 | #include <linux/module.h> |
Tejun Heo | 5a0e3ad | 2010-03-24 17:04:11 +0900 | [diff] [blame] | 22 | #include <linux/gfp.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 23 | #include <net/tcp.h> |
| 24 | |
Brian Haley | ab32ea5 | 2006-09-22 14:15:41 -0700 | [diff] [blame] | 25 | int sysctl_tcp_syn_retries __read_mostly = TCP_SYN_RETRIES; |
| 26 | int sysctl_tcp_synack_retries __read_mostly = TCP_SYNACK_RETRIES; |
| 27 | int sysctl_tcp_keepalive_time __read_mostly = TCP_KEEPALIVE_TIME; |
| 28 | int sysctl_tcp_keepalive_probes __read_mostly = TCP_KEEPALIVE_PROBES; |
| 29 | int sysctl_tcp_keepalive_intvl __read_mostly = TCP_KEEPALIVE_INTVL; |
| 30 | int sysctl_tcp_retries1 __read_mostly = TCP_RETR1; |
| 31 | int sysctl_tcp_retries2 __read_mostly = TCP_RETR2; |
| 32 | int sysctl_tcp_orphan_retries __read_mostly; |
Andreas Petlund | 36e31b0 | 2010-02-18 02:47:01 +0000 | [diff] [blame] | 33 | int sysctl_tcp_thin_linear_timeouts __read_mostly; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 34 | |
| 35 | static void tcp_write_timer(unsigned long); |
| 36 | static void tcp_delack_timer(unsigned long); |
| 37 | static void tcp_keepalive_timer (unsigned long data); |
| 38 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 39 | void tcp_init_xmit_timers(struct sock *sk) |
| 40 | { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 41 | inet_csk_init_xmit_timers(sk, &tcp_write_timer, &tcp_delack_timer, |
| 42 | &tcp_keepalive_timer); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | } |
Arnaldo Carvalho de Melo | 3f421ba | 2005-08-09 20:11:08 -0700 | [diff] [blame] | 44 | EXPORT_SYMBOL(tcp_init_xmit_timers); |
| 45 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 46 | static void tcp_write_err(struct sock *sk) |
| 47 | { |
| 48 | sk->sk_err = sk->sk_err_soft ? : ETIMEDOUT; |
| 49 | sk->sk_error_report(sk); |
| 50 | |
| 51 | tcp_done(sk); |
Pavel Emelyanov | de0744a | 2008-07-16 20:31:16 -0700 | [diff] [blame] | 52 | NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPABORTONTIMEOUT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 53 | } |
| 54 | |
| 55 | /* Do not allow orphaned sockets to eat all our resources. |
| 56 | * This is direct violation of TCP specs, but it is required |
| 57 | * to prevent DoS attacks. It is called when a retransmission timeout |
| 58 | * or zero probe timeout occurs on orphaned socket. |
| 59 | * |
Stephen Hemminger | caa20d9a | 2005-11-10 17:13:47 -0800 | [diff] [blame] | 60 | * Criteria is still not confirmed experimentally and may change. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 61 | * We kill the socket, if: |
| 62 | * 1. If number of orphaned sockets exceeds an administratively configured |
| 63 | * limit. |
| 64 | * 2. If we have strong memory pressure. |
| 65 | */ |
| 66 | static int tcp_out_of_resources(struct sock *sk, int do_reset) |
| 67 | { |
| 68 | struct tcp_sock *tp = tcp_sk(sk); |
David S. Miller | ad1af0f | 2010-08-25 02:27:49 -0700 | [diff] [blame] | 69 | int shift = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 70 | |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 71 | /* If peer does not open window for long time, or did not transmit |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 72 | * anything for long time, penalize it. */ |
| 73 | if ((s32)(tcp_time_stamp - tp->lsndtime) > 2*TCP_RTO_MAX || !do_reset) |
David S. Miller | ad1af0f | 2010-08-25 02:27:49 -0700 | [diff] [blame] | 74 | shift++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 75 | |
| 76 | /* If some dubious ICMP arrived, penalize even more. */ |
| 77 | if (sk->sk_err_soft) |
David S. Miller | ad1af0f | 2010-08-25 02:27:49 -0700 | [diff] [blame] | 78 | shift++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 79 | |
David S. Miller | ad1af0f | 2010-08-25 02:27:49 -0700 | [diff] [blame] | 80 | if (tcp_too_many_orphans(sk, shift)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 81 | if (net_ratelimit()) |
| 82 | printk(KERN_INFO "Out of socket memory\n"); |
| 83 | |
| 84 | /* Catch exceptional cases, when connection requires reset. |
| 85 | * 1. Last segment was sent recently. */ |
| 86 | if ((s32)(tcp_time_stamp - tp->lsndtime) <= TCP_TIMEWAIT_LEN || |
| 87 | /* 2. Window is closed. */ |
| 88 | (!tp->snd_wnd && !tp->packets_out)) |
| 89 | do_reset = 1; |
| 90 | if (do_reset) |
| 91 | tcp_send_active_reset(sk, GFP_ATOMIC); |
| 92 | tcp_done(sk); |
Pavel Emelyanov | de0744a | 2008-07-16 20:31:16 -0700 | [diff] [blame] | 93 | NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPABORTONMEMORY); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 94 | return 1; |
| 95 | } |
| 96 | return 0; |
| 97 | } |
| 98 | |
| 99 | /* Calculate maximal number or retries on an orphaned socket. */ |
| 100 | static int tcp_orphan_retries(struct sock *sk, int alive) |
| 101 | { |
| 102 | int retries = sysctl_tcp_orphan_retries; /* May be zero. */ |
| 103 | |
| 104 | /* We know from an ICMP that something is wrong. */ |
| 105 | if (sk->sk_err_soft && !alive) |
| 106 | retries = 0; |
| 107 | |
| 108 | /* However, if socket sent something recently, select some safe |
| 109 | * number of retries. 8 corresponds to >100 seconds with minimal |
| 110 | * RTO of 200msec. */ |
| 111 | if (retries == 0 && alive) |
| 112 | retries = 8; |
| 113 | return retries; |
| 114 | } |
| 115 | |
Eric Dumazet | ce55dd3 | 2007-12-21 01:50:43 -0800 | [diff] [blame] | 116 | static void tcp_mtu_probing(struct inet_connection_sock *icsk, struct sock *sk) |
| 117 | { |
Eric Dumazet | ce55dd3 | 2007-12-21 01:50:43 -0800 | [diff] [blame] | 118 | /* Black hole detection */ |
| 119 | if (sysctl_tcp_mtu_probing) { |
| 120 | if (!icsk->icsk_mtup.enabled) { |
| 121 | icsk->icsk_mtup.enabled = 1; |
| 122 | tcp_sync_mss(sk, icsk->icsk_pmtu_cookie); |
| 123 | } else { |
| 124 | struct tcp_sock *tp = tcp_sk(sk); |
David S. Miller | 829942c | 2007-12-21 04:29:16 -0800 | [diff] [blame] | 125 | int mss; |
| 126 | |
Eric Dumazet | 8beb5c5 | 2007-12-21 05:58:29 -0800 | [diff] [blame] | 127 | mss = tcp_mtu_to_mss(sk, icsk->icsk_mtup.search_low) >> 1; |
Eric Dumazet | ce55dd3 | 2007-12-21 01:50:43 -0800 | [diff] [blame] | 128 | mss = min(sysctl_tcp_base_mss, mss); |
| 129 | mss = max(mss, 68 - tp->tcp_header_len); |
| 130 | icsk->icsk_mtup.search_low = tcp_mss_to_mtu(sk, mss); |
| 131 | tcp_sync_mss(sk, icsk->icsk_pmtu_cookie); |
| 132 | } |
| 133 | } |
| 134 | } |
| 135 | |
Damian Lukowski | 2f7de57 | 2009-12-07 06:06:16 +0000 | [diff] [blame] | 136 | /* This function calculates a "timeout" which is equivalent to the timeout of a |
Daniel Mack | 3ad2f3f | 2010-02-03 08:01:28 +0800 | [diff] [blame] | 137 | * TCP connection after "boundary" unsuccessful, exponentially backed-off |
Damian Lukowski | 4d22f7d | 2010-09-28 13:08:32 -0700 | [diff] [blame] | 138 | * retransmissions with an initial RTO of TCP_RTO_MIN or TCP_TIMEOUT_INIT if |
| 139 | * syn_set flag is set. |
Damian Lukowski | 2f7de57 | 2009-12-07 06:06:16 +0000 | [diff] [blame] | 140 | */ |
| 141 | static bool retransmits_timed_out(struct sock *sk, |
Jerry Chu | dca43c7 | 2010-08-27 19:13:28 +0000 | [diff] [blame] | 142 | unsigned int boundary, |
David S. Miller | 21a180c | 2010-10-04 11:56:38 -0700 | [diff] [blame] | 143 | unsigned int timeout, |
Damian Lukowski | 4d22f7d | 2010-09-28 13:08:32 -0700 | [diff] [blame] | 144 | bool syn_set) |
Damian Lukowski | 2f7de57 | 2009-12-07 06:06:16 +0000 | [diff] [blame] | 145 | { |
Jerry Chu | dca43c7 | 2010-08-27 19:13:28 +0000 | [diff] [blame] | 146 | unsigned int linear_backoff_thresh, start_ts; |
Damian Lukowski | 4d22f7d | 2010-09-28 13:08:32 -0700 | [diff] [blame] | 147 | unsigned int rto_base = syn_set ? TCP_TIMEOUT_INIT : TCP_RTO_MIN; |
Damian Lukowski | 2f7de57 | 2009-12-07 06:06:16 +0000 | [diff] [blame] | 148 | |
| 149 | if (!inet_csk(sk)->icsk_retransmits) |
| 150 | return false; |
| 151 | |
| 152 | if (unlikely(!tcp_sk(sk)->retrans_stamp)) |
| 153 | start_ts = TCP_SKB_CB(tcp_write_queue_head(sk))->when; |
| 154 | else |
| 155 | start_ts = tcp_sk(sk)->retrans_stamp; |
| 156 | |
Jerry Chu | dca43c7 | 2010-08-27 19:13:28 +0000 | [diff] [blame] | 157 | if (likely(timeout == 0)) { |
David S. Miller | 21a180c | 2010-10-04 11:56:38 -0700 | [diff] [blame] | 158 | linear_backoff_thresh = ilog2(TCP_RTO_MAX/rto_base); |
Damian Lukowski | 2f7de57 | 2009-12-07 06:06:16 +0000 | [diff] [blame] | 159 | |
Jerry Chu | dca43c7 | 2010-08-27 19:13:28 +0000 | [diff] [blame] | 160 | if (boundary <= linear_backoff_thresh) |
David S. Miller | 21a180c | 2010-10-04 11:56:38 -0700 | [diff] [blame] | 161 | timeout = ((2 << boundary) - 1) * rto_base; |
Jerry Chu | dca43c7 | 2010-08-27 19:13:28 +0000 | [diff] [blame] | 162 | else |
David S. Miller | 21a180c | 2010-10-04 11:56:38 -0700 | [diff] [blame] | 163 | timeout = ((2 << linear_backoff_thresh) - 1) * rto_base + |
Jerry Chu | dca43c7 | 2010-08-27 19:13:28 +0000 | [diff] [blame] | 164 | (boundary - linear_backoff_thresh) * TCP_RTO_MAX; |
| 165 | } |
Damian Lukowski | 2f7de57 | 2009-12-07 06:06:16 +0000 | [diff] [blame] | 166 | return (tcp_time_stamp - start_ts) >= timeout; |
| 167 | } |
| 168 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 169 | /* A write timeout has occurred. Process the after effects. */ |
| 170 | static int tcp_write_timeout(struct sock *sk) |
| 171 | { |
John Heffner | 5d424d5 | 2006-03-20 17:53:41 -0800 | [diff] [blame] | 172 | struct inet_connection_sock *icsk = inet_csk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 173 | int retry_until; |
Rusty Russell | 3db1cd5 | 2011-12-19 13:56:45 +0000 | [diff] [blame] | 174 | bool do_reset, syn_set = false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 175 | |
| 176 | if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 177 | if (icsk->icsk_retransmits) |
Eric Dumazet | b6c6712 | 2010-04-08 23:03:29 +0000 | [diff] [blame] | 178 | dst_negative_advice(sk); |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 179 | retry_until = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries; |
Rusty Russell | 3db1cd5 | 2011-12-19 13:56:45 +0000 | [diff] [blame] | 180 | syn_set = true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 181 | } else { |
David S. Miller | 21a180c | 2010-10-04 11:56:38 -0700 | [diff] [blame] | 182 | if (retransmits_timed_out(sk, sysctl_tcp_retries1, 0, 0)) { |
John Heffner | 5d424d5 | 2006-03-20 17:53:41 -0800 | [diff] [blame] | 183 | /* Black hole detection */ |
Eric Dumazet | ce55dd3 | 2007-12-21 01:50:43 -0800 | [diff] [blame] | 184 | tcp_mtu_probing(icsk, sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 185 | |
Eric Dumazet | b6c6712 | 2010-04-08 23:03:29 +0000 | [diff] [blame] | 186 | dst_negative_advice(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 187 | } |
| 188 | |
| 189 | retry_until = sysctl_tcp_retries2; |
| 190 | if (sock_flag(sk, SOCK_DEAD)) { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 191 | const int alive = (icsk->icsk_rto < TCP_RTO_MAX); |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 192 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 193 | retry_until = tcp_orphan_retries(sk, alive); |
Damian Lukowski | 6fa12c8 | 2009-08-26 00:16:34 +0000 | [diff] [blame] | 194 | do_reset = alive || |
David S. Miller | 21a180c | 2010-10-04 11:56:38 -0700 | [diff] [blame] | 195 | !retransmits_timed_out(sk, retry_until, 0, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 196 | |
Damian Lukowski | 6fa12c8 | 2009-08-26 00:16:34 +0000 | [diff] [blame] | 197 | if (tcp_out_of_resources(sk, do_reset)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 198 | return 1; |
| 199 | } |
| 200 | } |
| 201 | |
Jerry Chu | dca43c7 | 2010-08-27 19:13:28 +0000 | [diff] [blame] | 202 | if (retransmits_timed_out(sk, retry_until, |
David S. Miller | 21a180c | 2010-10-04 11:56:38 -0700 | [diff] [blame] | 203 | syn_set ? 0 : icsk->icsk_user_timeout, syn_set)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 204 | /* Has it gone just too far? */ |
| 205 | tcp_write_err(sk); |
| 206 | return 1; |
| 207 | } |
| 208 | return 0; |
| 209 | } |
| 210 | |
| 211 | static void tcp_delack_timer(unsigned long data) |
| 212 | { |
Jianjun Kong | fd3f8c4 | 2008-11-03 02:47:38 -0800 | [diff] [blame] | 213 | struct sock *sk = (struct sock *)data; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 214 | struct tcp_sock *tp = tcp_sk(sk); |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 215 | struct inet_connection_sock *icsk = inet_csk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 216 | |
| 217 | bh_lock_sock(sk); |
| 218 | if (sock_owned_by_user(sk)) { |
| 219 | /* Try again later. */ |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 220 | icsk->icsk_ack.blocked = 1; |
Pavel Emelyanov | de0744a | 2008-07-16 20:31:16 -0700 | [diff] [blame] | 221 | NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_DELAYEDACKLOCKED); |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 222 | sk_reset_timer(sk, &icsk->icsk_delack_timer, jiffies + TCP_DELACK_MIN); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 223 | goto out_unlock; |
| 224 | } |
| 225 | |
David S. Miller | 9993e7d | 2008-01-10 21:56:38 -0800 | [diff] [blame] | 226 | sk_mem_reclaim_partial(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 227 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 228 | if (sk->sk_state == TCP_CLOSE || !(icsk->icsk_ack.pending & ICSK_ACK_TIMER)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 229 | goto out; |
| 230 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 231 | if (time_after(icsk->icsk_ack.timeout, jiffies)) { |
| 232 | sk_reset_timer(sk, &icsk->icsk_delack_timer, icsk->icsk_ack.timeout); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 233 | goto out; |
| 234 | } |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 235 | icsk->icsk_ack.pending &= ~ICSK_ACK_TIMER; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 236 | |
David S. Miller | b03efcf | 2005-07-08 14:57:23 -0700 | [diff] [blame] | 237 | if (!skb_queue_empty(&tp->ucopy.prequeue)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 238 | struct sk_buff *skb; |
| 239 | |
Pavel Emelyanov | de0744a | 2008-07-16 20:31:16 -0700 | [diff] [blame] | 240 | NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPSCHEDULERFAILED); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 241 | |
| 242 | while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) |
Peter Zijlstra | c57943a | 2008-10-07 14:18:42 -0700 | [diff] [blame] | 243 | sk_backlog_rcv(sk, skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 244 | |
| 245 | tp->ucopy.memory = 0; |
| 246 | } |
| 247 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 248 | if (inet_csk_ack_scheduled(sk)) { |
| 249 | if (!icsk->icsk_ack.pingpong) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 250 | /* Delayed ACK missed: inflate ATO. */ |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 251 | icsk->icsk_ack.ato = min(icsk->icsk_ack.ato << 1, icsk->icsk_rto); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 252 | } else { |
| 253 | /* Delayed ACK missed: leave pingpong mode and |
| 254 | * deflate ATO. |
| 255 | */ |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 256 | icsk->icsk_ack.pingpong = 0; |
| 257 | icsk->icsk_ack.ato = TCP_ATO_MIN; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 258 | } |
| 259 | tcp_send_ack(sk); |
Pavel Emelyanov | de0744a | 2008-07-16 20:31:16 -0700 | [diff] [blame] | 260 | NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_DELAYEDACKS); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 261 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 262 | |
| 263 | out: |
Glauber Costa | 180d8cd | 2011-12-11 21:47:02 +0000 | [diff] [blame] | 264 | if (sk_under_memory_pressure(sk)) |
Hideo Aoki | 3ab224b | 2007-12-31 00:11:19 -0800 | [diff] [blame] | 265 | sk_mem_reclaim(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 266 | out_unlock: |
| 267 | bh_unlock_sock(sk); |
| 268 | sock_put(sk); |
| 269 | } |
| 270 | |
| 271 | static void tcp_probe_timer(struct sock *sk) |
| 272 | { |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 273 | struct inet_connection_sock *icsk = inet_csk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 274 | struct tcp_sock *tp = tcp_sk(sk); |
| 275 | int max_probes; |
| 276 | |
David S. Miller | fe067e8 | 2007-03-07 12:12:44 -0800 | [diff] [blame] | 277 | if (tp->packets_out || !tcp_send_head(sk)) { |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 278 | icsk->icsk_probes_out = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 279 | return; |
| 280 | } |
| 281 | |
| 282 | /* *WARNING* RFC 1122 forbids this |
| 283 | * |
| 284 | * It doesn't AFAIK, because we kill the retransmit timer -AK |
| 285 | * |
| 286 | * FIXME: We ought not to do it, Solaris 2.5 actually has fixing |
| 287 | * this behaviour in Solaris down as a bug fix. [AC] |
| 288 | * |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 289 | * Let me to explain. icsk_probes_out is zeroed by incoming ACKs |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 290 | * even if they advertise zero window. Hence, connection is killed only |
| 291 | * if we received no ACKs for normal connection timeout. It is not killed |
| 292 | * only because window stays zero for some time, window may be zero |
| 293 | * until armageddon and even later. We are in full accordance |
| 294 | * with RFCs, only probe timer combines both retransmission timeout |
| 295 | * and probe timeout in one bottle. --ANK |
| 296 | */ |
| 297 | max_probes = sysctl_tcp_retries2; |
| 298 | |
| 299 | if (sock_flag(sk, SOCK_DEAD)) { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 300 | const int alive = ((icsk->icsk_rto << icsk->icsk_backoff) < TCP_RTO_MAX); |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 301 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 302 | max_probes = tcp_orphan_retries(sk, alive); |
| 303 | |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 304 | if (tcp_out_of_resources(sk, alive || icsk->icsk_probes_out <= max_probes)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 305 | return; |
| 306 | } |
| 307 | |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 308 | if (icsk->icsk_probes_out > max_probes) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 309 | tcp_write_err(sk); |
| 310 | } else { |
| 311 | /* Only send another probe if we didn't close things up. */ |
| 312 | tcp_send_probe0(sk); |
| 313 | } |
| 314 | } |
| 315 | |
| 316 | /* |
| 317 | * The TCP retransmit timer. |
| 318 | */ |
| 319 | |
Damian Lukowski | f1ecd5d | 2009-08-26 00:16:31 +0000 | [diff] [blame] | 320 | void tcp_retransmit_timer(struct sock *sk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 321 | { |
| 322 | struct tcp_sock *tp = tcp_sk(sk); |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 323 | struct inet_connection_sock *icsk = inet_csk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 324 | |
| 325 | if (!tp->packets_out) |
| 326 | goto out; |
| 327 | |
Ilpo Järvinen | 547b792 | 2008-07-25 21:43:18 -0700 | [diff] [blame] | 328 | WARN_ON(tcp_write_queue_empty(sk)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 329 | |
| 330 | if (!tp->snd_wnd && !sock_flag(sk, SOCK_DEAD) && |
| 331 | !((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))) { |
| 332 | /* Receiver dastardly shrinks window. Our retransmits |
| 333 | * become zero probes, but we should not timeout this |
| 334 | * connection. If the socket is an orphan, time it out, |
| 335 | * we cannot allow such beasts to hang infinitely. |
| 336 | */ |
YOSHIFUJI Hideaki | 569508c | 2008-04-14 04:09:36 -0700 | [diff] [blame] | 337 | struct inet_sock *inet = inet_sk(sk); |
| 338 | if (sk->sk_family == AF_INET) { |
Matt Mackall | 6086ebc | 2008-12-18 19:54:22 -0800 | [diff] [blame] | 339 | LIMIT_NETDEBUG(KERN_DEBUG "TCP: Peer %pI4:%u/%u unexpectedly shrunk window %u:%u (repaired)\n", |
Eric Dumazet | c720c7e | 2009-10-15 06:30:45 +0000 | [diff] [blame] | 340 | &inet->inet_daddr, ntohs(inet->inet_dport), |
| 341 | inet->inet_num, tp->snd_una, tp->snd_nxt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 342 | } |
Eric Dumazet | dfd56b8 | 2011-12-10 09:48:31 +0000 | [diff] [blame] | 343 | #if IS_ENABLED(CONFIG_IPV6) |
YOSHIFUJI Hideaki | 569508c | 2008-04-14 04:09:36 -0700 | [diff] [blame] | 344 | else if (sk->sk_family == AF_INET6) { |
| 345 | struct ipv6_pinfo *np = inet6_sk(sk); |
Matt Mackall | 6086ebc | 2008-12-18 19:54:22 -0800 | [diff] [blame] | 346 | LIMIT_NETDEBUG(KERN_DEBUG "TCP: Peer %pI6:%u/%u unexpectedly shrunk window %u:%u (repaired)\n", |
Eric Dumazet | c720c7e | 2009-10-15 06:30:45 +0000 | [diff] [blame] | 347 | &np->daddr, ntohs(inet->inet_dport), |
| 348 | inet->inet_num, tp->snd_una, tp->snd_nxt); |
YOSHIFUJI Hideaki | 569508c | 2008-04-14 04:09:36 -0700 | [diff] [blame] | 349 | } |
| 350 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 351 | if (tcp_time_stamp - tp->rcv_tstamp > TCP_RTO_MAX) { |
| 352 | tcp_write_err(sk); |
| 353 | goto out; |
| 354 | } |
| 355 | tcp_enter_loss(sk, 0); |
David S. Miller | fe067e8 | 2007-03-07 12:12:44 -0800 | [diff] [blame] | 356 | tcp_retransmit_skb(sk, tcp_write_queue_head(sk)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 357 | __sk_dst_reset(sk); |
| 358 | goto out_reset_timer; |
| 359 | } |
| 360 | |
| 361 | if (tcp_write_timeout(sk)) |
| 362 | goto out; |
| 363 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 364 | if (icsk->icsk_retransmits == 0) { |
Pavel Emelyanov | 40b215e | 2008-07-03 01:05:41 -0700 | [diff] [blame] | 365 | int mib_idx; |
| 366 | |
Ilpo Järvinen | c60ce4e | 2010-10-14 01:52:09 +0000 | [diff] [blame] | 367 | if (icsk->icsk_ca_state == TCP_CA_Recovery) { |
Ilpo Järvinen | bc079e9 | 2009-02-28 04:44:34 +0000 | [diff] [blame] | 368 | if (tcp_is_sack(tp)) |
| 369 | mib_idx = LINUX_MIB_TCPSACKRECOVERYFAIL; |
| 370 | else |
| 371 | mib_idx = LINUX_MIB_TCPRENORECOVERYFAIL; |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 372 | } else if (icsk->icsk_ca_state == TCP_CA_Loss) { |
Pavel Emelyanov | 40b215e | 2008-07-03 01:05:41 -0700 | [diff] [blame] | 373 | mib_idx = LINUX_MIB_TCPLOSSFAILURES; |
Ilpo Järvinen | c60ce4e | 2010-10-14 01:52:09 +0000 | [diff] [blame] | 374 | } else if ((icsk->icsk_ca_state == TCP_CA_Disorder) || |
| 375 | tp->sacked_out) { |
| 376 | if (tcp_is_sack(tp)) |
| 377 | mib_idx = LINUX_MIB_TCPSACKFAILURES; |
| 378 | else |
| 379 | mib_idx = LINUX_MIB_TCPRENOFAILURES; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 380 | } else { |
Pavel Emelyanov | 40b215e | 2008-07-03 01:05:41 -0700 | [diff] [blame] | 381 | mib_idx = LINUX_MIB_TCPTIMEOUTS; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 382 | } |
Pavel Emelyanov | de0744a | 2008-07-16 20:31:16 -0700 | [diff] [blame] | 383 | NET_INC_STATS_BH(sock_net(sk), mib_idx); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 384 | } |
| 385 | |
| 386 | if (tcp_use_frto(sk)) { |
| 387 | tcp_enter_frto(sk); |
| 388 | } else { |
| 389 | tcp_enter_loss(sk, 0); |
| 390 | } |
| 391 | |
David S. Miller | fe067e8 | 2007-03-07 12:12:44 -0800 | [diff] [blame] | 392 | if (tcp_retransmit_skb(sk, tcp_write_queue_head(sk)) > 0) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 393 | /* Retransmission failed because of local congestion, |
| 394 | * do not backoff. |
| 395 | */ |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 396 | if (!icsk->icsk_retransmits) |
| 397 | icsk->icsk_retransmits = 1; |
| 398 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, |
Arnaldo Carvalho de Melo | 3f421ba | 2005-08-09 20:11:08 -0700 | [diff] [blame] | 399 | min(icsk->icsk_rto, TCP_RESOURCE_PROBE_INTERVAL), |
| 400 | TCP_RTO_MAX); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 401 | goto out; |
| 402 | } |
| 403 | |
| 404 | /* Increase the timeout each time we retransmit. Note that |
| 405 | * we do not increase the rtt estimate. rto is initialized |
| 406 | * from rtt, but increases here. Jacobson (SIGCOMM 88) suggests |
| 407 | * that doubling rto each time is the least we can get away with. |
| 408 | * In KA9Q, Karn uses this for the first few times, and then |
| 409 | * goes to quadratic. netBSD doubles, but only goes up to *64, |
| 410 | * and clamps at 1 to 64 sec afterwards. Note that 120 sec is |
| 411 | * defined in the protocol as the maximum possible RTT. I guess |
| 412 | * we'll have to use something other than TCP to talk to the |
| 413 | * University of Mars. |
| 414 | * |
| 415 | * PAWS allows us longer timeouts and large windows, so once |
| 416 | * implemented ftp to mars will work nicely. We will have to fix |
| 417 | * the 120 second clamps though! |
| 418 | */ |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 419 | icsk->icsk_backoff++; |
| 420 | icsk->icsk_retransmits++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 421 | |
| 422 | out_reset_timer: |
Andreas Petlund | 36e31b0 | 2010-02-18 02:47:01 +0000 | [diff] [blame] | 423 | /* If stream is thin, use linear timeouts. Since 'icsk_backoff' is |
| 424 | * used to reset timer, set to 0. Recalculate 'icsk_rto' as this |
| 425 | * might be increased if the stream oscillates between thin and thick, |
| 426 | * thus the old value might already be too high compared to the value |
| 427 | * set by 'tcp_set_rto' in tcp_input.c which resets the rto without |
| 428 | * backoff. Limit to TCP_THIN_LINEAR_RETRIES before initiating |
| 429 | * exponential backoff behaviour to avoid continue hammering |
| 430 | * linear-timeout retransmissions into a black hole |
| 431 | */ |
| 432 | if (sk->sk_state == TCP_ESTABLISHED && |
| 433 | (tp->thin_lto || sysctl_tcp_thin_linear_timeouts) && |
| 434 | tcp_stream_is_thin(tp) && |
| 435 | icsk->icsk_retransmits <= TCP_THIN_LINEAR_RETRIES) { |
| 436 | icsk->icsk_backoff = 0; |
| 437 | icsk->icsk_rto = min(__tcp_set_rto(tp), TCP_RTO_MAX); |
| 438 | } else { |
| 439 | /* Use normal (exponential) backoff */ |
| 440 | icsk->icsk_rto = min(icsk->icsk_rto << 1, TCP_RTO_MAX); |
| 441 | } |
Arnaldo Carvalho de Melo | 3f421ba | 2005-08-09 20:11:08 -0700 | [diff] [blame] | 442 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, icsk->icsk_rto, TCP_RTO_MAX); |
David S. Miller | 21a180c | 2010-10-04 11:56:38 -0700 | [diff] [blame] | 443 | if (retransmits_timed_out(sk, sysctl_tcp_retries1 + 1, 0, 0)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 444 | __sk_dst_reset(sk); |
| 445 | |
| 446 | out:; |
| 447 | } |
| 448 | |
| 449 | static void tcp_write_timer(unsigned long data) |
| 450 | { |
Jianjun Kong | fd3f8c4 | 2008-11-03 02:47:38 -0800 | [diff] [blame] | 451 | struct sock *sk = (struct sock *)data; |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 452 | struct inet_connection_sock *icsk = inet_csk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 453 | int event; |
| 454 | |
| 455 | bh_lock_sock(sk); |
| 456 | if (sock_owned_by_user(sk)) { |
| 457 | /* Try again later */ |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 458 | sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + (HZ / 20)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 459 | goto out_unlock; |
| 460 | } |
| 461 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 462 | if (sk->sk_state == TCP_CLOSE || !icsk->icsk_pending) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 463 | goto out; |
| 464 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 465 | if (time_after(icsk->icsk_timeout, jiffies)) { |
| 466 | sk_reset_timer(sk, &icsk->icsk_retransmit_timer, icsk->icsk_timeout); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 467 | goto out; |
| 468 | } |
| 469 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 470 | event = icsk->icsk_pending; |
| 471 | icsk->icsk_pending = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 472 | |
| 473 | switch (event) { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 474 | case ICSK_TIME_RETRANS: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 475 | tcp_retransmit_timer(sk); |
| 476 | break; |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 477 | case ICSK_TIME_PROBE0: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 478 | tcp_probe_timer(sk); |
| 479 | break; |
| 480 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 481 | |
| 482 | out: |
Hideo Aoki | 3ab224b | 2007-12-31 00:11:19 -0800 | [diff] [blame] | 483 | sk_mem_reclaim(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 484 | out_unlock: |
| 485 | bh_unlock_sock(sk); |
| 486 | sock_put(sk); |
| 487 | } |
| 488 | |
Arnaldo Carvalho de Melo | 295f732 | 2005-08-09 20:11:56 -0700 | [diff] [blame] | 489 | /* |
| 490 | * Timer for listening sockets |
| 491 | */ |
| 492 | |
| 493 | static void tcp_synack_timer(struct sock *sk) |
| 494 | { |
Arnaldo Carvalho de Melo | a019d6f | 2005-08-09 20:15:09 -0700 | [diff] [blame] | 495 | inet_csk_reqsk_queue_prune(sk, TCP_SYNQ_INTERVAL, |
| 496 | TCP_TIMEOUT_INIT, TCP_RTO_MAX); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 497 | } |
| 498 | |
Octavian Purdila | 72659ec | 2010-01-17 19:09:39 -0800 | [diff] [blame] | 499 | void tcp_syn_ack_timeout(struct sock *sk, struct request_sock *req) |
| 500 | { |
| 501 | NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPTIMEOUTS); |
| 502 | } |
| 503 | EXPORT_SYMBOL(tcp_syn_ack_timeout); |
| 504 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 505 | void tcp_set_keepalive(struct sock *sk, int val) |
| 506 | { |
| 507 | if ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)) |
| 508 | return; |
| 509 | |
| 510 | if (val && !sock_flag(sk, SOCK_KEEPOPEN)) |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 511 | inet_csk_reset_keepalive_timer(sk, keepalive_time_when(tcp_sk(sk))); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 512 | else if (!val) |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 513 | inet_csk_delete_keepalive_timer(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 514 | } |
| 515 | |
| 516 | |
| 517 | static void tcp_keepalive_timer (unsigned long data) |
| 518 | { |
| 519 | struct sock *sk = (struct sock *) data; |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 520 | struct inet_connection_sock *icsk = inet_csk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 521 | struct tcp_sock *tp = tcp_sk(sk); |
Flavio Leitner | 6c37e5d | 2010-04-26 18:33:27 +0000 | [diff] [blame] | 522 | u32 elapsed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 523 | |
| 524 | /* Only process if socket is not in use. */ |
| 525 | bh_lock_sock(sk); |
| 526 | if (sock_owned_by_user(sk)) { |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 527 | /* Try again later. */ |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 528 | inet_csk_reset_keepalive_timer (sk, HZ/20); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 529 | goto out; |
| 530 | } |
| 531 | |
| 532 | if (sk->sk_state == TCP_LISTEN) { |
| 533 | tcp_synack_timer(sk); |
| 534 | goto out; |
| 535 | } |
| 536 | |
| 537 | if (sk->sk_state == TCP_FIN_WAIT2 && sock_flag(sk, SOCK_DEAD)) { |
| 538 | if (tp->linger2 >= 0) { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 539 | const int tmo = tcp_fin_time(sk) - TCP_TIMEWAIT_LEN; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 540 | |
| 541 | if (tmo > 0) { |
| 542 | tcp_time_wait(sk, TCP_FIN_WAIT2, tmo); |
| 543 | goto out; |
| 544 | } |
| 545 | } |
| 546 | tcp_send_active_reset(sk, GFP_ATOMIC); |
| 547 | goto death; |
| 548 | } |
| 549 | |
| 550 | if (!sock_flag(sk, SOCK_KEEPOPEN) || sk->sk_state == TCP_CLOSE) |
| 551 | goto out; |
| 552 | |
| 553 | elapsed = keepalive_time_when(tp); |
| 554 | |
| 555 | /* It is alive without keepalive 8) */ |
David S. Miller | fe067e8 | 2007-03-07 12:12:44 -0800 | [diff] [blame] | 556 | if (tp->packets_out || tcp_send_head(sk)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 557 | goto resched; |
| 558 | |
Flavio Leitner | 6c37e5d | 2010-04-26 18:33:27 +0000 | [diff] [blame] | 559 | elapsed = keepalive_time_elapsed(tp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 560 | |
| 561 | if (elapsed >= keepalive_time_when(tp)) { |
Jerry Chu | dca43c7 | 2010-08-27 19:13:28 +0000 | [diff] [blame] | 562 | /* If the TCP_USER_TIMEOUT option is enabled, use that |
| 563 | * to determine when to timeout instead. |
| 564 | */ |
| 565 | if ((icsk->icsk_user_timeout != 0 && |
| 566 | elapsed >= icsk->icsk_user_timeout && |
| 567 | icsk->icsk_probes_out > 0) || |
| 568 | (icsk->icsk_user_timeout == 0 && |
| 569 | icsk->icsk_probes_out >= keepalive_probes(tp))) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 570 | tcp_send_active_reset(sk, GFP_ATOMIC); |
| 571 | tcp_write_err(sk); |
| 572 | goto out; |
| 573 | } |
| 574 | if (tcp_write_wakeup(sk) <= 0) { |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 575 | icsk->icsk_probes_out++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 576 | elapsed = keepalive_intvl_when(tp); |
| 577 | } else { |
| 578 | /* If keepalive was lost due to local congestion, |
| 579 | * try harder. |
| 580 | */ |
| 581 | elapsed = TCP_RESOURCE_PROBE_INTERVAL; |
| 582 | } |
| 583 | } else { |
| 584 | /* It is tp->rcv_tstamp + keepalive_time_when(tp) */ |
| 585 | elapsed = keepalive_time_when(tp) - elapsed; |
| 586 | } |
| 587 | |
Hideo Aoki | 3ab224b | 2007-12-31 00:11:19 -0800 | [diff] [blame] | 588 | sk_mem_reclaim(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 589 | |
| 590 | resched: |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 591 | inet_csk_reset_keepalive_timer (sk, elapsed); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 592 | goto out; |
| 593 | |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 594 | death: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 595 | tcp_done(sk); |
| 596 | |
| 597 | out: |
| 598 | bh_unlock_sock(sk); |
| 599 | sock_put(sk); |
| 600 | } |