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 | 36e31b0a | 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 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 35 | static void tcp_write_err(struct sock *sk) |
| 36 | { |
| 37 | sk->sk_err = sk->sk_err_soft ? : ETIMEDOUT; |
| 38 | sk->sk_error_report(sk); |
| 39 | |
| 40 | tcp_done(sk); |
Pavel Emelyanov | de0744a | 2008-07-16 20:31:16 -0700 | [diff] [blame] | 41 | NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPABORTONTIMEOUT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 42 | } |
| 43 | |
| 44 | /* Do not allow orphaned sockets to eat all our resources. |
| 45 | * This is direct violation of TCP specs, but it is required |
| 46 | * to prevent DoS attacks. It is called when a retransmission timeout |
| 47 | * or zero probe timeout occurs on orphaned socket. |
| 48 | * |
Stephen Hemminger | caa20d9a | 2005-11-10 17:13:47 -0800 | [diff] [blame] | 49 | * Criteria is still not confirmed experimentally and may change. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 50 | * We kill the socket, if: |
| 51 | * 1. If number of orphaned sockets exceeds an administratively configured |
| 52 | * limit. |
| 53 | * 2. If we have strong memory pressure. |
| 54 | */ |
| 55 | static int tcp_out_of_resources(struct sock *sk, int do_reset) |
| 56 | { |
| 57 | struct tcp_sock *tp = tcp_sk(sk); |
David S. Miller | ad1af0f | 2010-08-25 02:27:49 -0700 | [diff] [blame] | 58 | int shift = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 59 | |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 60 | /* 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] | 61 | * anything for long time, penalize it. */ |
| 62 | 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] | 63 | shift++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 64 | |
| 65 | /* If some dubious ICMP arrived, penalize even more. */ |
| 66 | if (sk->sk_err_soft) |
David S. Miller | ad1af0f | 2010-08-25 02:27:49 -0700 | [diff] [blame] | 67 | shift++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 68 | |
Arun Sharma | efcdbf2 | 2012-01-30 14:16:06 -0800 | [diff] [blame] | 69 | if (tcp_check_oom(sk, shift)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 70 | /* Catch exceptional cases, when connection requires reset. |
| 71 | * 1. Last segment was sent recently. */ |
| 72 | if ((s32)(tcp_time_stamp - tp->lsndtime) <= TCP_TIMEWAIT_LEN || |
| 73 | /* 2. Window is closed. */ |
| 74 | (!tp->snd_wnd && !tp->packets_out)) |
| 75 | do_reset = 1; |
| 76 | if (do_reset) |
| 77 | tcp_send_active_reset(sk, GFP_ATOMIC); |
| 78 | tcp_done(sk); |
Pavel Emelyanov | de0744a | 2008-07-16 20:31:16 -0700 | [diff] [blame] | 79 | NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPABORTONMEMORY); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 80 | return 1; |
| 81 | } |
| 82 | return 0; |
| 83 | } |
| 84 | |
| 85 | /* Calculate maximal number or retries on an orphaned socket. */ |
| 86 | static int tcp_orphan_retries(struct sock *sk, int alive) |
| 87 | { |
| 88 | int retries = sysctl_tcp_orphan_retries; /* May be zero. */ |
| 89 | |
| 90 | /* We know from an ICMP that something is wrong. */ |
| 91 | if (sk->sk_err_soft && !alive) |
| 92 | retries = 0; |
| 93 | |
| 94 | /* However, if socket sent something recently, select some safe |
| 95 | * number of retries. 8 corresponds to >100 seconds with minimal |
| 96 | * RTO of 200msec. */ |
| 97 | if (retries == 0 && alive) |
| 98 | retries = 8; |
| 99 | return retries; |
| 100 | } |
| 101 | |
Eric Dumazet | ce55dd3 | 2007-12-21 01:50:43 -0800 | [diff] [blame] | 102 | static void tcp_mtu_probing(struct inet_connection_sock *icsk, struct sock *sk) |
| 103 | { |
Eric Dumazet | ce55dd3 | 2007-12-21 01:50:43 -0800 | [diff] [blame] | 104 | /* Black hole detection */ |
| 105 | if (sysctl_tcp_mtu_probing) { |
| 106 | if (!icsk->icsk_mtup.enabled) { |
| 107 | icsk->icsk_mtup.enabled = 1; |
| 108 | tcp_sync_mss(sk, icsk->icsk_pmtu_cookie); |
| 109 | } else { |
| 110 | struct tcp_sock *tp = tcp_sk(sk); |
David S. Miller | 829942c | 2007-12-21 04:29:16 -0800 | [diff] [blame] | 111 | int mss; |
| 112 | |
Eric Dumazet | 8beb5c5 | 2007-12-21 05:58:29 -0800 | [diff] [blame] | 113 | mss = tcp_mtu_to_mss(sk, icsk->icsk_mtup.search_low) >> 1; |
Eric Dumazet | ce55dd3 | 2007-12-21 01:50:43 -0800 | [diff] [blame] | 114 | mss = min(sysctl_tcp_base_mss, mss); |
| 115 | mss = max(mss, 68 - tp->tcp_header_len); |
| 116 | icsk->icsk_mtup.search_low = tcp_mss_to_mtu(sk, mss); |
| 117 | tcp_sync_mss(sk, icsk->icsk_pmtu_cookie); |
| 118 | } |
| 119 | } |
| 120 | } |
| 121 | |
Damian Lukowski | 2f7de57 | 2009-12-07 06:06:16 +0000 | [diff] [blame] | 122 | /* 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] | 123 | * TCP connection after "boundary" unsuccessful, exponentially backed-off |
Damian Lukowski | 4d22f7d | 2010-09-28 13:08:32 -0700 | [diff] [blame] | 124 | * retransmissions with an initial RTO of TCP_RTO_MIN or TCP_TIMEOUT_INIT if |
| 125 | * syn_set flag is set. |
Damian Lukowski | 2f7de57 | 2009-12-07 06:06:16 +0000 | [diff] [blame] | 126 | */ |
| 127 | static bool retransmits_timed_out(struct sock *sk, |
Jerry Chu | dca43c7 | 2010-08-27 19:13:28 +0000 | [diff] [blame] | 128 | unsigned int boundary, |
David S. Miller | 21a180c | 2010-10-04 11:56:38 -0700 | [diff] [blame] | 129 | unsigned int timeout, |
Damian Lukowski | 4d22f7d | 2010-09-28 13:08:32 -0700 | [diff] [blame] | 130 | bool syn_set) |
Damian Lukowski | 2f7de57 | 2009-12-07 06:06:16 +0000 | [diff] [blame] | 131 | { |
Jerry Chu | dca43c7 | 2010-08-27 19:13:28 +0000 | [diff] [blame] | 132 | unsigned int linear_backoff_thresh, start_ts; |
Damian Lukowski | 4d22f7d | 2010-09-28 13:08:32 -0700 | [diff] [blame] | 133 | unsigned int rto_base = syn_set ? TCP_TIMEOUT_INIT : TCP_RTO_MIN; |
Damian Lukowski | 2f7de57 | 2009-12-07 06:06:16 +0000 | [diff] [blame] | 134 | |
| 135 | if (!inet_csk(sk)->icsk_retransmits) |
| 136 | return false; |
| 137 | |
| 138 | if (unlikely(!tcp_sk(sk)->retrans_stamp)) |
| 139 | start_ts = TCP_SKB_CB(tcp_write_queue_head(sk))->when; |
| 140 | else |
| 141 | start_ts = tcp_sk(sk)->retrans_stamp; |
| 142 | |
Jerry Chu | dca43c7 | 2010-08-27 19:13:28 +0000 | [diff] [blame] | 143 | if (likely(timeout == 0)) { |
David S. Miller | 21a180c | 2010-10-04 11:56:38 -0700 | [diff] [blame] | 144 | linear_backoff_thresh = ilog2(TCP_RTO_MAX/rto_base); |
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 | if (boundary <= linear_backoff_thresh) |
David S. Miller | 21a180c | 2010-10-04 11:56:38 -0700 | [diff] [blame] | 147 | timeout = ((2 << boundary) - 1) * rto_base; |
Jerry Chu | dca43c7 | 2010-08-27 19:13:28 +0000 | [diff] [blame] | 148 | else |
David S. Miller | 21a180c | 2010-10-04 11:56:38 -0700 | [diff] [blame] | 149 | timeout = ((2 << linear_backoff_thresh) - 1) * rto_base + |
Jerry Chu | dca43c7 | 2010-08-27 19:13:28 +0000 | [diff] [blame] | 150 | (boundary - linear_backoff_thresh) * TCP_RTO_MAX; |
| 151 | } |
Damian Lukowski | 2f7de57 | 2009-12-07 06:06:16 +0000 | [diff] [blame] | 152 | return (tcp_time_stamp - start_ts) >= timeout; |
| 153 | } |
| 154 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 155 | /* A write timeout has occurred. Process the after effects. */ |
| 156 | static int tcp_write_timeout(struct sock *sk) |
| 157 | { |
John Heffner | 5d424d5 | 2006-03-20 17:53:41 -0800 | [diff] [blame] | 158 | struct inet_connection_sock *icsk = inet_csk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 159 | int retry_until; |
Rusty Russell | 3db1cd5 | 2011-12-19 13:56:45 +0000 | [diff] [blame] | 160 | bool do_reset, syn_set = false; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 161 | |
| 162 | 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] | 163 | if (icsk->icsk_retransmits) |
Eric Dumazet | b6c6712 | 2010-04-08 23:03:29 +0000 | [diff] [blame] | 164 | dst_negative_advice(sk); |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 165 | retry_until = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries; |
Rusty Russell | 3db1cd5 | 2011-12-19 13:56:45 +0000 | [diff] [blame] | 166 | syn_set = true; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 167 | } else { |
David S. Miller | 21a180c | 2010-10-04 11:56:38 -0700 | [diff] [blame] | 168 | if (retransmits_timed_out(sk, sysctl_tcp_retries1, 0, 0)) { |
John Heffner | 5d424d5 | 2006-03-20 17:53:41 -0800 | [diff] [blame] | 169 | /* Black hole detection */ |
Eric Dumazet | ce55dd3 | 2007-12-21 01:50:43 -0800 | [diff] [blame] | 170 | tcp_mtu_probing(icsk, sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 171 | |
Eric Dumazet | b6c6712 | 2010-04-08 23:03:29 +0000 | [diff] [blame] | 172 | dst_negative_advice(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 173 | } |
| 174 | |
| 175 | retry_until = sysctl_tcp_retries2; |
| 176 | if (sock_flag(sk, SOCK_DEAD)) { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 177 | const int alive = (icsk->icsk_rto < TCP_RTO_MAX); |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 178 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 179 | retry_until = tcp_orphan_retries(sk, alive); |
Damian Lukowski | 6fa12c8 | 2009-08-26 00:16:34 +0000 | [diff] [blame] | 180 | do_reset = alive || |
David S. Miller | 21a180c | 2010-10-04 11:56:38 -0700 | [diff] [blame] | 181 | !retransmits_timed_out(sk, retry_until, 0, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 182 | |
Damian Lukowski | 6fa12c8 | 2009-08-26 00:16:34 +0000 | [diff] [blame] | 183 | if (tcp_out_of_resources(sk, do_reset)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 184 | return 1; |
| 185 | } |
| 186 | } |
| 187 | |
Jerry Chu | dca43c7 | 2010-08-27 19:13:28 +0000 | [diff] [blame] | 188 | if (retransmits_timed_out(sk, retry_until, |
David S. Miller | 21a180c | 2010-10-04 11:56:38 -0700 | [diff] [blame] | 189 | syn_set ? 0 : icsk->icsk_user_timeout, syn_set)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 190 | /* Has it gone just too far? */ |
| 191 | tcp_write_err(sk); |
| 192 | return 1; |
| 193 | } |
| 194 | return 0; |
| 195 | } |
| 196 | |
Eric Dumazet | 6f458df | 2012-07-20 05:45:50 +0000 | [diff] [blame] | 197 | void tcp_delack_timer_handler(struct sock *sk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 198 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 199 | struct tcp_sock *tp = tcp_sk(sk); |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 200 | struct inet_connection_sock *icsk = inet_csk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 201 | |
David S. Miller | 9993e7d | 2008-01-10 21:56:38 -0800 | [diff] [blame] | 202 | sk_mem_reclaim_partial(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 203 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 204 | 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] | 205 | goto out; |
| 206 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 207 | if (time_after(icsk->icsk_ack.timeout, jiffies)) { |
| 208 | sk_reset_timer(sk, &icsk->icsk_delack_timer, icsk->icsk_ack.timeout); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 209 | goto out; |
| 210 | } |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 211 | icsk->icsk_ack.pending &= ~ICSK_ACK_TIMER; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 212 | |
David S. Miller | b03efcf | 2005-07-08 14:57:23 -0700 | [diff] [blame] | 213 | if (!skb_queue_empty(&tp->ucopy.prequeue)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 214 | struct sk_buff *skb; |
| 215 | |
Pavel Emelyanov | de0744a | 2008-07-16 20:31:16 -0700 | [diff] [blame] | 216 | NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPSCHEDULERFAILED); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 217 | |
| 218 | while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) |
Peter Zijlstra | c57943a | 2008-10-07 14:18:42 -0700 | [diff] [blame] | 219 | sk_backlog_rcv(sk, skb); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 220 | |
| 221 | tp->ucopy.memory = 0; |
| 222 | } |
| 223 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 224 | if (inet_csk_ack_scheduled(sk)) { |
| 225 | if (!icsk->icsk_ack.pingpong) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 226 | /* Delayed ACK missed: inflate ATO. */ |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 227 | 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] | 228 | } else { |
| 229 | /* Delayed ACK missed: leave pingpong mode and |
| 230 | * deflate ATO. |
| 231 | */ |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 232 | icsk->icsk_ack.pingpong = 0; |
| 233 | icsk->icsk_ack.ato = TCP_ATO_MIN; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 234 | } |
| 235 | tcp_send_ack(sk); |
Pavel Emelyanov | de0744a | 2008-07-16 20:31:16 -0700 | [diff] [blame] | 236 | NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_DELAYEDACKS); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 237 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 238 | |
| 239 | out: |
Glauber Costa | 180d8cd | 2011-12-11 21:47:02 +0000 | [diff] [blame] | 240 | if (sk_under_memory_pressure(sk)) |
Hideo Aoki | 3ab224b | 2007-12-31 00:11:19 -0800 | [diff] [blame] | 241 | sk_mem_reclaim(sk); |
Eric Dumazet | 6f458df | 2012-07-20 05:45:50 +0000 | [diff] [blame] | 242 | } |
| 243 | |
| 244 | static void tcp_delack_timer(unsigned long data) |
| 245 | { |
| 246 | struct sock *sk = (struct sock *)data; |
| 247 | |
| 248 | bh_lock_sock(sk); |
| 249 | if (!sock_owned_by_user(sk)) { |
| 250 | tcp_delack_timer_handler(sk); |
| 251 | } else { |
| 252 | inet_csk(sk)->icsk_ack.blocked = 1; |
| 253 | NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_DELAYEDACKLOCKED); |
| 254 | /* deleguate our work to tcp_release_cb() */ |
Eric Dumazet | 144d56e | 2012-08-20 00:22:46 +0000 | [diff] [blame] | 255 | if (!test_and_set_bit(TCP_DELACK_TIMER_DEFERRED, &tcp_sk(sk)->tsq_flags)) |
| 256 | sock_hold(sk); |
Eric Dumazet | 6f458df | 2012-07-20 05:45:50 +0000 | [diff] [blame] | 257 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 258 | bh_unlock_sock(sk); |
| 259 | sock_put(sk); |
| 260 | } |
| 261 | |
| 262 | static void tcp_probe_timer(struct sock *sk) |
| 263 | { |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 264 | struct inet_connection_sock *icsk = inet_csk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 265 | struct tcp_sock *tp = tcp_sk(sk); |
| 266 | int max_probes; |
| 267 | |
David S. Miller | fe067e8 | 2007-03-07 12:12:44 -0800 | [diff] [blame] | 268 | if (tp->packets_out || !tcp_send_head(sk)) { |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 269 | icsk->icsk_probes_out = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 270 | return; |
| 271 | } |
| 272 | |
| 273 | /* *WARNING* RFC 1122 forbids this |
| 274 | * |
| 275 | * It doesn't AFAIK, because we kill the retransmit timer -AK |
| 276 | * |
| 277 | * FIXME: We ought not to do it, Solaris 2.5 actually has fixing |
| 278 | * this behaviour in Solaris down as a bug fix. [AC] |
| 279 | * |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 280 | * Let me to explain. icsk_probes_out is zeroed by incoming ACKs |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 281 | * even if they advertise zero window. Hence, connection is killed only |
| 282 | * if we received no ACKs for normal connection timeout. It is not killed |
| 283 | * only because window stays zero for some time, window may be zero |
| 284 | * until armageddon and even later. We are in full accordance |
| 285 | * with RFCs, only probe timer combines both retransmission timeout |
| 286 | * and probe timeout in one bottle. --ANK |
| 287 | */ |
| 288 | max_probes = sysctl_tcp_retries2; |
| 289 | |
| 290 | if (sock_flag(sk, SOCK_DEAD)) { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 291 | const int alive = ((icsk->icsk_rto << icsk->icsk_backoff) < TCP_RTO_MAX); |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 292 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 293 | max_probes = tcp_orphan_retries(sk, alive); |
| 294 | |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 295 | 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] | 296 | return; |
| 297 | } |
| 298 | |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 299 | if (icsk->icsk_probes_out > max_probes) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 300 | tcp_write_err(sk); |
| 301 | } else { |
| 302 | /* Only send another probe if we didn't close things up. */ |
| 303 | tcp_send_probe0(sk); |
| 304 | } |
| 305 | } |
| 306 | |
| 307 | /* |
Jerry Chu | 8336886 | 2012-08-31 12:29:12 +0000 | [diff] [blame] | 308 | * Timer for Fast Open socket to retransmit SYNACK. Note that the |
| 309 | * sk here is the child socket, not the parent (listener) socket. |
| 310 | */ |
| 311 | static void tcp_fastopen_synack_timer(struct sock *sk) |
| 312 | { |
| 313 | struct inet_connection_sock *icsk = inet_csk(sk); |
| 314 | int max_retries = icsk->icsk_syn_retries ? : |
| 315 | sysctl_tcp_synack_retries + 1; /* add one more retry for fastopen */ |
| 316 | struct request_sock *req; |
| 317 | |
| 318 | req = tcp_sk(sk)->fastopen_rsk; |
| 319 | req->rsk_ops->syn_ack_timeout(sk, req); |
| 320 | |
Eric Dumazet | e6c022a | 2012-10-27 23:16:46 +0000 | [diff] [blame] | 321 | if (req->num_timeout >= max_retries) { |
Jerry Chu | 8336886 | 2012-08-31 12:29:12 +0000 | [diff] [blame] | 322 | tcp_write_err(sk); |
| 323 | return; |
| 324 | } |
| 325 | /* XXX (TFO) - Unlike regular SYN-ACK retransmit, we ignore error |
| 326 | * returned from rtx_syn_ack() to make it more persistent like |
| 327 | * regular retransmit because if the child socket has been accepted |
| 328 | * it's not good to give up too easily. |
| 329 | */ |
Eric Dumazet | e6c022a | 2012-10-27 23:16:46 +0000 | [diff] [blame] | 330 | inet_rtx_syn_ack(sk, req); |
| 331 | req->num_timeout++; |
Jerry Chu | 8336886 | 2012-08-31 12:29:12 +0000 | [diff] [blame] | 332 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, |
Eric Dumazet | e6c022a | 2012-10-27 23:16:46 +0000 | [diff] [blame] | 333 | TCP_TIMEOUT_INIT << req->num_timeout, TCP_RTO_MAX); |
Jerry Chu | 8336886 | 2012-08-31 12:29:12 +0000 | [diff] [blame] | 334 | } |
| 335 | |
| 336 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 337 | * The TCP retransmit timer. |
| 338 | */ |
| 339 | |
Damian Lukowski | f1ecd5d | 2009-08-26 00:16:31 +0000 | [diff] [blame] | 340 | void tcp_retransmit_timer(struct sock *sk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 341 | { |
| 342 | struct tcp_sock *tp = tcp_sk(sk); |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 343 | struct inet_connection_sock *icsk = inet_csk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 344 | |
Yuchung Cheng | 750ea2b | 2012-05-02 13:30:04 +0000 | [diff] [blame] | 345 | if (tp->early_retrans_delayed) { |
| 346 | tcp_resume_early_retransmit(sk); |
| 347 | return; |
| 348 | } |
Jerry Chu | 8336886 | 2012-08-31 12:29:12 +0000 | [diff] [blame] | 349 | if (tp->fastopen_rsk) { |
Jerry Chu | 37561f6 | 2012-10-22 11:26:36 +0000 | [diff] [blame] | 350 | WARN_ON_ONCE(sk->sk_state != TCP_SYN_RECV && |
| 351 | sk->sk_state != TCP_FIN_WAIT1); |
Jerry Chu | 8336886 | 2012-08-31 12:29:12 +0000 | [diff] [blame] | 352 | tcp_fastopen_synack_timer(sk); |
| 353 | /* Before we receive ACK to our SYN-ACK don't retransmit |
| 354 | * anything else (e.g., data or FIN segments). |
| 355 | */ |
| 356 | return; |
| 357 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 358 | if (!tp->packets_out) |
| 359 | goto out; |
| 360 | |
Ilpo Järvinen | 547b792 | 2008-07-25 21:43:18 -0700 | [diff] [blame] | 361 | WARN_ON(tcp_write_queue_empty(sk)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 362 | |
| 363 | if (!tp->snd_wnd && !sock_flag(sk, SOCK_DEAD) && |
| 364 | !((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))) { |
| 365 | /* Receiver dastardly shrinks window. Our retransmits |
| 366 | * become zero probes, but we should not timeout this |
| 367 | * connection. If the socket is an orphan, time it out, |
| 368 | * we cannot allow such beasts to hang infinitely. |
| 369 | */ |
YOSHIFUJI Hideaki | 569508c | 2008-04-14 04:09:36 -0700 | [diff] [blame] | 370 | struct inet_sock *inet = inet_sk(sk); |
| 371 | if (sk->sk_family == AF_INET) { |
Joe Perches | afd46503 | 2012-03-12 07:03:32 +0000 | [diff] [blame] | 372 | LIMIT_NETDEBUG(KERN_DEBUG pr_fmt("Peer %pI4:%u/%u unexpectedly shrunk window %u:%u (repaired)\n"), |
| 373 | &inet->inet_daddr, |
| 374 | ntohs(inet->inet_dport), inet->inet_num, |
| 375 | tp->snd_una, tp->snd_nxt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 376 | } |
Eric Dumazet | dfd56b8 | 2011-12-10 09:48:31 +0000 | [diff] [blame] | 377 | #if IS_ENABLED(CONFIG_IPV6) |
YOSHIFUJI Hideaki | 569508c | 2008-04-14 04:09:36 -0700 | [diff] [blame] | 378 | else if (sk->sk_family == AF_INET6) { |
| 379 | struct ipv6_pinfo *np = inet6_sk(sk); |
Joe Perches | afd46503 | 2012-03-12 07:03:32 +0000 | [diff] [blame] | 380 | LIMIT_NETDEBUG(KERN_DEBUG pr_fmt("Peer %pI6:%u/%u unexpectedly shrunk window %u:%u (repaired)\n"), |
| 381 | &np->daddr, |
| 382 | ntohs(inet->inet_dport), inet->inet_num, |
| 383 | tp->snd_una, tp->snd_nxt); |
YOSHIFUJI Hideaki | 569508c | 2008-04-14 04:09:36 -0700 | [diff] [blame] | 384 | } |
| 385 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 386 | if (tcp_time_stamp - tp->rcv_tstamp > TCP_RTO_MAX) { |
| 387 | tcp_write_err(sk); |
| 388 | goto out; |
| 389 | } |
| 390 | tcp_enter_loss(sk, 0); |
David S. Miller | fe067e8 | 2007-03-07 12:12:44 -0800 | [diff] [blame] | 391 | tcp_retransmit_skb(sk, tcp_write_queue_head(sk)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 392 | __sk_dst_reset(sk); |
| 393 | goto out_reset_timer; |
| 394 | } |
| 395 | |
| 396 | if (tcp_write_timeout(sk)) |
| 397 | goto out; |
| 398 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 399 | if (icsk->icsk_retransmits == 0) { |
Pavel Emelyanov | 40b215e | 2008-07-03 01:05:41 -0700 | [diff] [blame] | 400 | int mib_idx; |
| 401 | |
Ilpo Järvinen | c60ce4e | 2010-10-14 01:52:09 +0000 | [diff] [blame] | 402 | if (icsk->icsk_ca_state == TCP_CA_Recovery) { |
Ilpo Järvinen | bc079e9 | 2009-02-28 04:44:34 +0000 | [diff] [blame] | 403 | if (tcp_is_sack(tp)) |
| 404 | mib_idx = LINUX_MIB_TCPSACKRECOVERYFAIL; |
| 405 | else |
| 406 | mib_idx = LINUX_MIB_TCPRENORECOVERYFAIL; |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 407 | } else if (icsk->icsk_ca_state == TCP_CA_Loss) { |
Pavel Emelyanov | 40b215e | 2008-07-03 01:05:41 -0700 | [diff] [blame] | 408 | mib_idx = LINUX_MIB_TCPLOSSFAILURES; |
Ilpo Järvinen | c60ce4e | 2010-10-14 01:52:09 +0000 | [diff] [blame] | 409 | } else if ((icsk->icsk_ca_state == TCP_CA_Disorder) || |
| 410 | tp->sacked_out) { |
| 411 | if (tcp_is_sack(tp)) |
| 412 | mib_idx = LINUX_MIB_TCPSACKFAILURES; |
| 413 | else |
| 414 | mib_idx = LINUX_MIB_TCPRENOFAILURES; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 415 | } else { |
Pavel Emelyanov | 40b215e | 2008-07-03 01:05:41 -0700 | [diff] [blame] | 416 | mib_idx = LINUX_MIB_TCPTIMEOUTS; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 417 | } |
Pavel Emelyanov | de0744a | 2008-07-16 20:31:16 -0700 | [diff] [blame] | 418 | NET_INC_STATS_BH(sock_net(sk), mib_idx); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 419 | } |
| 420 | |
| 421 | if (tcp_use_frto(sk)) { |
| 422 | tcp_enter_frto(sk); |
| 423 | } else { |
| 424 | tcp_enter_loss(sk, 0); |
| 425 | } |
| 426 | |
David S. Miller | fe067e8 | 2007-03-07 12:12:44 -0800 | [diff] [blame] | 427 | if (tcp_retransmit_skb(sk, tcp_write_queue_head(sk)) > 0) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 428 | /* Retransmission failed because of local congestion, |
| 429 | * do not backoff. |
| 430 | */ |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 431 | if (!icsk->icsk_retransmits) |
| 432 | icsk->icsk_retransmits = 1; |
| 433 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, |
Arnaldo Carvalho de Melo | 3f421ba | 2005-08-09 20:11:08 -0700 | [diff] [blame] | 434 | min(icsk->icsk_rto, TCP_RESOURCE_PROBE_INTERVAL), |
| 435 | TCP_RTO_MAX); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 436 | goto out; |
| 437 | } |
| 438 | |
| 439 | /* Increase the timeout each time we retransmit. Note that |
| 440 | * we do not increase the rtt estimate. rto is initialized |
| 441 | * from rtt, but increases here. Jacobson (SIGCOMM 88) suggests |
| 442 | * that doubling rto each time is the least we can get away with. |
| 443 | * In KA9Q, Karn uses this for the first few times, and then |
| 444 | * goes to quadratic. netBSD doubles, but only goes up to *64, |
| 445 | * and clamps at 1 to 64 sec afterwards. Note that 120 sec is |
| 446 | * defined in the protocol as the maximum possible RTT. I guess |
| 447 | * we'll have to use something other than TCP to talk to the |
| 448 | * University of Mars. |
| 449 | * |
| 450 | * PAWS allows us longer timeouts and large windows, so once |
| 451 | * implemented ftp to mars will work nicely. We will have to fix |
| 452 | * the 120 second clamps though! |
| 453 | */ |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 454 | icsk->icsk_backoff++; |
| 455 | icsk->icsk_retransmits++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 456 | |
| 457 | out_reset_timer: |
Andreas Petlund | 36e31b0a | 2010-02-18 02:47:01 +0000 | [diff] [blame] | 458 | /* If stream is thin, use linear timeouts. Since 'icsk_backoff' is |
| 459 | * used to reset timer, set to 0. Recalculate 'icsk_rto' as this |
| 460 | * might be increased if the stream oscillates between thin and thick, |
| 461 | * thus the old value might already be too high compared to the value |
| 462 | * set by 'tcp_set_rto' in tcp_input.c which resets the rto without |
| 463 | * backoff. Limit to TCP_THIN_LINEAR_RETRIES before initiating |
| 464 | * exponential backoff behaviour to avoid continue hammering |
| 465 | * linear-timeout retransmissions into a black hole |
| 466 | */ |
| 467 | if (sk->sk_state == TCP_ESTABLISHED && |
| 468 | (tp->thin_lto || sysctl_tcp_thin_linear_timeouts) && |
| 469 | tcp_stream_is_thin(tp) && |
| 470 | icsk->icsk_retransmits <= TCP_THIN_LINEAR_RETRIES) { |
| 471 | icsk->icsk_backoff = 0; |
| 472 | icsk->icsk_rto = min(__tcp_set_rto(tp), TCP_RTO_MAX); |
| 473 | } else { |
| 474 | /* Use normal (exponential) backoff */ |
| 475 | icsk->icsk_rto = min(icsk->icsk_rto << 1, TCP_RTO_MAX); |
| 476 | } |
Arnaldo Carvalho de Melo | 3f421ba | 2005-08-09 20:11:08 -0700 | [diff] [blame] | 477 | 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] | 478 | if (retransmits_timed_out(sk, sysctl_tcp_retries1 + 1, 0, 0)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 479 | __sk_dst_reset(sk); |
| 480 | |
| 481 | out:; |
| 482 | } |
| 483 | |
Eric Dumazet | 6f458df | 2012-07-20 05:45:50 +0000 | [diff] [blame] | 484 | void tcp_write_timer_handler(struct sock *sk) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 485 | { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 486 | struct inet_connection_sock *icsk = inet_csk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 487 | int event; |
| 488 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 489 | if (sk->sk_state == TCP_CLOSE || !icsk->icsk_pending) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 490 | goto out; |
| 491 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 492 | if (time_after(icsk->icsk_timeout, jiffies)) { |
| 493 | sk_reset_timer(sk, &icsk->icsk_retransmit_timer, icsk->icsk_timeout); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 494 | goto out; |
| 495 | } |
| 496 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 497 | event = icsk->icsk_pending; |
| 498 | icsk->icsk_pending = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 499 | |
| 500 | switch (event) { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 501 | case ICSK_TIME_RETRANS: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 502 | tcp_retransmit_timer(sk); |
| 503 | break; |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 504 | case ICSK_TIME_PROBE0: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 505 | tcp_probe_timer(sk); |
| 506 | break; |
| 507 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 508 | |
| 509 | out: |
Hideo Aoki | 3ab224b | 2007-12-31 00:11:19 -0800 | [diff] [blame] | 510 | sk_mem_reclaim(sk); |
Eric Dumazet | 6f458df | 2012-07-20 05:45:50 +0000 | [diff] [blame] | 511 | } |
| 512 | |
| 513 | static void tcp_write_timer(unsigned long data) |
| 514 | { |
| 515 | struct sock *sk = (struct sock *)data; |
| 516 | |
| 517 | bh_lock_sock(sk); |
| 518 | if (!sock_owned_by_user(sk)) { |
| 519 | tcp_write_timer_handler(sk); |
| 520 | } else { |
| 521 | /* deleguate our work to tcp_release_cb() */ |
Eric Dumazet | 144d56e | 2012-08-20 00:22:46 +0000 | [diff] [blame] | 522 | if (!test_and_set_bit(TCP_WRITE_TIMER_DEFERRED, &tcp_sk(sk)->tsq_flags)) |
| 523 | sock_hold(sk); |
Eric Dumazet | 6f458df | 2012-07-20 05:45:50 +0000 | [diff] [blame] | 524 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 525 | bh_unlock_sock(sk); |
| 526 | sock_put(sk); |
| 527 | } |
| 528 | |
Arnaldo Carvalho de Melo | 295f732 | 2005-08-09 20:11:56 -0700 | [diff] [blame] | 529 | /* |
| 530 | * Timer for listening sockets |
| 531 | */ |
| 532 | |
| 533 | static void tcp_synack_timer(struct sock *sk) |
| 534 | { |
Arnaldo Carvalho de Melo | a019d6f | 2005-08-09 20:15:09 -0700 | [diff] [blame] | 535 | inet_csk_reqsk_queue_prune(sk, TCP_SYNQ_INTERVAL, |
| 536 | TCP_TIMEOUT_INIT, TCP_RTO_MAX); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 537 | } |
| 538 | |
Octavian Purdila | 72659ec | 2010-01-17 19:09:39 -0800 | [diff] [blame] | 539 | void tcp_syn_ack_timeout(struct sock *sk, struct request_sock *req) |
| 540 | { |
| 541 | NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPTIMEOUTS); |
| 542 | } |
| 543 | EXPORT_SYMBOL(tcp_syn_ack_timeout); |
| 544 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 545 | void tcp_set_keepalive(struct sock *sk, int val) |
| 546 | { |
| 547 | if ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)) |
| 548 | return; |
| 549 | |
| 550 | if (val && !sock_flag(sk, SOCK_KEEPOPEN)) |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 551 | inet_csk_reset_keepalive_timer(sk, keepalive_time_when(tcp_sk(sk))); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 552 | else if (!val) |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 553 | inet_csk_delete_keepalive_timer(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 554 | } |
| 555 | |
| 556 | |
| 557 | static void tcp_keepalive_timer (unsigned long data) |
| 558 | { |
| 559 | struct sock *sk = (struct sock *) data; |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 560 | struct inet_connection_sock *icsk = inet_csk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 561 | struct tcp_sock *tp = tcp_sk(sk); |
Flavio Leitner | 6c37e5d | 2010-04-26 18:33:27 +0000 | [diff] [blame] | 562 | u32 elapsed; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 563 | |
| 564 | /* Only process if socket is not in use. */ |
| 565 | bh_lock_sock(sk); |
| 566 | if (sock_owned_by_user(sk)) { |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 567 | /* Try again later. */ |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 568 | inet_csk_reset_keepalive_timer (sk, HZ/20); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 569 | goto out; |
| 570 | } |
| 571 | |
| 572 | if (sk->sk_state == TCP_LISTEN) { |
| 573 | tcp_synack_timer(sk); |
| 574 | goto out; |
| 575 | } |
| 576 | |
| 577 | if (sk->sk_state == TCP_FIN_WAIT2 && sock_flag(sk, SOCK_DEAD)) { |
| 578 | if (tp->linger2 >= 0) { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 579 | const int tmo = tcp_fin_time(sk) - TCP_TIMEWAIT_LEN; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 580 | |
| 581 | if (tmo > 0) { |
| 582 | tcp_time_wait(sk, TCP_FIN_WAIT2, tmo); |
| 583 | goto out; |
| 584 | } |
| 585 | } |
| 586 | tcp_send_active_reset(sk, GFP_ATOMIC); |
| 587 | goto death; |
| 588 | } |
| 589 | |
| 590 | if (!sock_flag(sk, SOCK_KEEPOPEN) || sk->sk_state == TCP_CLOSE) |
| 591 | goto out; |
| 592 | |
| 593 | elapsed = keepalive_time_when(tp); |
| 594 | |
| 595 | /* It is alive without keepalive 8) */ |
David S. Miller | fe067e8 | 2007-03-07 12:12:44 -0800 | [diff] [blame] | 596 | if (tp->packets_out || tcp_send_head(sk)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 597 | goto resched; |
| 598 | |
Flavio Leitner | 6c37e5d | 2010-04-26 18:33:27 +0000 | [diff] [blame] | 599 | elapsed = keepalive_time_elapsed(tp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 600 | |
| 601 | if (elapsed >= keepalive_time_when(tp)) { |
Jerry Chu | dca43c7 | 2010-08-27 19:13:28 +0000 | [diff] [blame] | 602 | /* If the TCP_USER_TIMEOUT option is enabled, use that |
| 603 | * to determine when to timeout instead. |
| 604 | */ |
| 605 | if ((icsk->icsk_user_timeout != 0 && |
| 606 | elapsed >= icsk->icsk_user_timeout && |
| 607 | icsk->icsk_probes_out > 0) || |
| 608 | (icsk->icsk_user_timeout == 0 && |
| 609 | icsk->icsk_probes_out >= keepalive_probes(tp))) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 610 | tcp_send_active_reset(sk, GFP_ATOMIC); |
| 611 | tcp_write_err(sk); |
| 612 | goto out; |
| 613 | } |
| 614 | if (tcp_write_wakeup(sk) <= 0) { |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 615 | icsk->icsk_probes_out++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 616 | elapsed = keepalive_intvl_when(tp); |
| 617 | } else { |
| 618 | /* If keepalive was lost due to local congestion, |
| 619 | * try harder. |
| 620 | */ |
| 621 | elapsed = TCP_RESOURCE_PROBE_INTERVAL; |
| 622 | } |
| 623 | } else { |
| 624 | /* It is tp->rcv_tstamp + keepalive_time_when(tp) */ |
| 625 | elapsed = keepalive_time_when(tp) - elapsed; |
| 626 | } |
| 627 | |
Hideo Aoki | 3ab224b | 2007-12-31 00:11:19 -0800 | [diff] [blame] | 628 | sk_mem_reclaim(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 629 | |
| 630 | resched: |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 631 | inet_csk_reset_keepalive_timer (sk, elapsed); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 632 | goto out; |
| 633 | |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 634 | death: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 635 | tcp_done(sk); |
| 636 | |
| 637 | out: |
| 638 | bh_unlock_sock(sk); |
| 639 | sock_put(sk); |
| 640 | } |
Eric Dumazet | 6f458df | 2012-07-20 05:45:50 +0000 | [diff] [blame] | 641 | |
| 642 | void tcp_init_xmit_timers(struct sock *sk) |
| 643 | { |
| 644 | inet_csk_init_xmit_timers(sk, &tcp_write_timer, &tcp_delack_timer, |
| 645 | &tcp_keepalive_timer); |
| 646 | } |
| 647 | EXPORT_SYMBOL(tcp_init_xmit_timers); |