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> |
| 22 | #include <net/tcp.h> |
| 23 | |
Brian Haley | ab32ea5 | 2006-09-22 14:15:41 -0700 | [diff] [blame] | 24 | int sysctl_tcp_syn_retries __read_mostly = TCP_SYN_RETRIES; |
| 25 | int sysctl_tcp_synack_retries __read_mostly = TCP_SYNACK_RETRIES; |
| 26 | int sysctl_tcp_keepalive_time __read_mostly = TCP_KEEPALIVE_TIME; |
| 27 | int sysctl_tcp_keepalive_probes __read_mostly = TCP_KEEPALIVE_PROBES; |
| 28 | int sysctl_tcp_keepalive_intvl __read_mostly = TCP_KEEPALIVE_INTVL; |
| 29 | int sysctl_tcp_retries1 __read_mostly = TCP_RETR1; |
| 30 | int sysctl_tcp_retries2 __read_mostly = TCP_RETR2; |
| 31 | int sysctl_tcp_orphan_retries __read_mostly; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 32 | |
| 33 | static void tcp_write_timer(unsigned long); |
| 34 | static void tcp_delack_timer(unsigned long); |
| 35 | static void tcp_keepalive_timer (unsigned long data); |
| 36 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 37 | void tcp_init_xmit_timers(struct sock *sk) |
| 38 | { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 39 | inet_csk_init_xmit_timers(sk, &tcp_write_timer, &tcp_delack_timer, |
| 40 | &tcp_keepalive_timer); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 41 | } |
| 42 | |
Arnaldo Carvalho de Melo | 3f421ba | 2005-08-09 20:11:08 -0700 | [diff] [blame] | 43 | EXPORT_SYMBOL(tcp_init_xmit_timers); |
| 44 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 45 | static void tcp_write_err(struct sock *sk) |
| 46 | { |
| 47 | sk->sk_err = sk->sk_err_soft ? : ETIMEDOUT; |
| 48 | sk->sk_error_report(sk); |
| 49 | |
| 50 | tcp_done(sk); |
| 51 | NET_INC_STATS_BH(LINUX_MIB_TCPABORTONTIMEOUT); |
| 52 | } |
| 53 | |
| 54 | /* Do not allow orphaned sockets to eat all our resources. |
| 55 | * This is direct violation of TCP specs, but it is required |
| 56 | * to prevent DoS attacks. It is called when a retransmission timeout |
| 57 | * or zero probe timeout occurs on orphaned socket. |
| 58 | * |
Stephen Hemminger | caa20d9a | 2005-11-10 17:13:47 -0800 | [diff] [blame] | 59 | * Criteria is still not confirmed experimentally and may change. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 60 | * We kill the socket, if: |
| 61 | * 1. If number of orphaned sockets exceeds an administratively configured |
| 62 | * limit. |
| 63 | * 2. If we have strong memory pressure. |
| 64 | */ |
| 65 | static int tcp_out_of_resources(struct sock *sk, int do_reset) |
| 66 | { |
| 67 | struct tcp_sock *tp = tcp_sk(sk); |
| 68 | int orphans = atomic_read(&tcp_orphan_count); |
| 69 | |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 70 | /* 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] | 71 | * anything for long time, penalize it. */ |
| 72 | if ((s32)(tcp_time_stamp - tp->lsndtime) > 2*TCP_RTO_MAX || !do_reset) |
| 73 | orphans <<= 1; |
| 74 | |
| 75 | /* If some dubious ICMP arrived, penalize even more. */ |
| 76 | if (sk->sk_err_soft) |
| 77 | orphans <<= 1; |
| 78 | |
Pavel Emelianov | e4fd5da | 2007-05-29 13:19:18 -0700 | [diff] [blame] | 79 | if (tcp_too_many_orphans(sk, orphans)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 80 | if (net_ratelimit()) |
| 81 | printk(KERN_INFO "Out of socket memory\n"); |
| 82 | |
| 83 | /* Catch exceptional cases, when connection requires reset. |
| 84 | * 1. Last segment was sent recently. */ |
| 85 | if ((s32)(tcp_time_stamp - tp->lsndtime) <= TCP_TIMEWAIT_LEN || |
| 86 | /* 2. Window is closed. */ |
| 87 | (!tp->snd_wnd && !tp->packets_out)) |
| 88 | do_reset = 1; |
| 89 | if (do_reset) |
| 90 | tcp_send_active_reset(sk, GFP_ATOMIC); |
| 91 | tcp_done(sk); |
| 92 | NET_INC_STATS_BH(LINUX_MIB_TCPABORTONMEMORY); |
| 93 | return 1; |
| 94 | } |
| 95 | return 0; |
| 96 | } |
| 97 | |
| 98 | /* Calculate maximal number or retries on an orphaned socket. */ |
| 99 | static int tcp_orphan_retries(struct sock *sk, int alive) |
| 100 | { |
| 101 | int retries = sysctl_tcp_orphan_retries; /* May be zero. */ |
| 102 | |
| 103 | /* We know from an ICMP that something is wrong. */ |
| 104 | if (sk->sk_err_soft && !alive) |
| 105 | retries = 0; |
| 106 | |
| 107 | /* However, if socket sent something recently, select some safe |
| 108 | * number of retries. 8 corresponds to >100 seconds with minimal |
| 109 | * RTO of 200msec. */ |
| 110 | if (retries == 0 && alive) |
| 111 | retries = 8; |
| 112 | return retries; |
| 113 | } |
| 114 | |
Eric Dumazet | ce55dd3 | 2007-12-21 01:50:43 -0800 | [diff] [blame] | 115 | static void tcp_mtu_probing(struct inet_connection_sock *icsk, struct sock *sk) |
| 116 | { |
Eric Dumazet | ce55dd3 | 2007-12-21 01:50:43 -0800 | [diff] [blame] | 117 | /* Black hole detection */ |
| 118 | if (sysctl_tcp_mtu_probing) { |
| 119 | if (!icsk->icsk_mtup.enabled) { |
| 120 | icsk->icsk_mtup.enabled = 1; |
| 121 | tcp_sync_mss(sk, icsk->icsk_pmtu_cookie); |
| 122 | } else { |
| 123 | struct tcp_sock *tp = tcp_sk(sk); |
David S. Miller | 829942c | 2007-12-21 04:29:16 -0800 | [diff] [blame] | 124 | int mss; |
| 125 | |
Eric Dumazet | 8beb5c5 | 2007-12-21 05:58:29 -0800 | [diff] [blame] | 126 | mss = tcp_mtu_to_mss(sk, icsk->icsk_mtup.search_low) >> 1; |
Eric Dumazet | ce55dd3 | 2007-12-21 01:50:43 -0800 | [diff] [blame] | 127 | mss = min(sysctl_tcp_base_mss, mss); |
| 128 | mss = max(mss, 68 - tp->tcp_header_len); |
| 129 | icsk->icsk_mtup.search_low = tcp_mss_to_mtu(sk, mss); |
| 130 | tcp_sync_mss(sk, icsk->icsk_pmtu_cookie); |
| 131 | } |
| 132 | } |
| 133 | } |
| 134 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 135 | /* A write timeout has occurred. Process the after effects. */ |
| 136 | static int tcp_write_timeout(struct sock *sk) |
| 137 | { |
John Heffner | 5d424d5 | 2006-03-20 17:53:41 -0800 | [diff] [blame] | 138 | struct inet_connection_sock *icsk = inet_csk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 139 | int retry_until; |
| 140 | |
| 141 | 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] | 142 | if (icsk->icsk_retransmits) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 143 | dst_negative_advice(&sk->sk_dst_cache); |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 144 | retry_until = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 145 | } else { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 146 | if (icsk->icsk_retransmits >= sysctl_tcp_retries1) { |
John Heffner | 5d424d5 | 2006-03-20 17:53:41 -0800 | [diff] [blame] | 147 | /* Black hole detection */ |
Eric Dumazet | ce55dd3 | 2007-12-21 01:50:43 -0800 | [diff] [blame] | 148 | tcp_mtu_probing(icsk, sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 149 | |
| 150 | dst_negative_advice(&sk->sk_dst_cache); |
| 151 | } |
| 152 | |
| 153 | retry_until = sysctl_tcp_retries2; |
| 154 | if (sock_flag(sk, SOCK_DEAD)) { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 155 | const int alive = (icsk->icsk_rto < TCP_RTO_MAX); |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 156 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 157 | retry_until = tcp_orphan_retries(sk, alive); |
| 158 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 159 | if (tcp_out_of_resources(sk, alive || icsk->icsk_retransmits < retry_until)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 160 | return 1; |
| 161 | } |
| 162 | } |
| 163 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 164 | if (icsk->icsk_retransmits >= retry_until) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 165 | /* Has it gone just too far? */ |
| 166 | tcp_write_err(sk); |
| 167 | return 1; |
| 168 | } |
| 169 | return 0; |
| 170 | } |
| 171 | |
| 172 | static void tcp_delack_timer(unsigned long data) |
| 173 | { |
| 174 | struct sock *sk = (struct sock*)data; |
| 175 | struct tcp_sock *tp = tcp_sk(sk); |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 176 | struct inet_connection_sock *icsk = inet_csk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 177 | |
| 178 | bh_lock_sock(sk); |
| 179 | if (sock_owned_by_user(sk)) { |
| 180 | /* Try again later. */ |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 181 | icsk->icsk_ack.blocked = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 182 | NET_INC_STATS_BH(LINUX_MIB_DELAYEDACKLOCKED); |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 183 | sk_reset_timer(sk, &icsk->icsk_delack_timer, jiffies + TCP_DELACK_MIN); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 184 | goto out_unlock; |
| 185 | } |
| 186 | |
David S. Miller | 9993e7d | 2008-01-10 21:56:38 -0800 | [diff] [blame] | 187 | sk_mem_reclaim_partial(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 188 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 189 | 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] | 190 | goto out; |
| 191 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 192 | if (time_after(icsk->icsk_ack.timeout, jiffies)) { |
| 193 | sk_reset_timer(sk, &icsk->icsk_delack_timer, icsk->icsk_ack.timeout); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 194 | goto out; |
| 195 | } |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 196 | icsk->icsk_ack.pending &= ~ICSK_ACK_TIMER; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 197 | |
David S. Miller | b03efcf | 2005-07-08 14:57:23 -0700 | [diff] [blame] | 198 | if (!skb_queue_empty(&tp->ucopy.prequeue)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 199 | struct sk_buff *skb; |
| 200 | |
David S. Miller | b03efcf | 2005-07-08 14:57:23 -0700 | [diff] [blame] | 201 | NET_INC_STATS_BH(LINUX_MIB_TCPSCHEDULERFAILED); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 202 | |
| 203 | while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) |
| 204 | sk->sk_backlog_rcv(sk, skb); |
| 205 | |
| 206 | tp->ucopy.memory = 0; |
| 207 | } |
| 208 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 209 | if (inet_csk_ack_scheduled(sk)) { |
| 210 | if (!icsk->icsk_ack.pingpong) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 211 | /* Delayed ACK missed: inflate ATO. */ |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 212 | 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] | 213 | } else { |
| 214 | /* Delayed ACK missed: leave pingpong mode and |
| 215 | * deflate ATO. |
| 216 | */ |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 217 | icsk->icsk_ack.pingpong = 0; |
| 218 | icsk->icsk_ack.ato = TCP_ATO_MIN; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 219 | } |
| 220 | tcp_send_ack(sk); |
| 221 | NET_INC_STATS_BH(LINUX_MIB_DELAYEDACKS); |
| 222 | } |
| 223 | TCP_CHECK_TIMER(sk); |
| 224 | |
| 225 | out: |
| 226 | if (tcp_memory_pressure) |
Hideo Aoki | 3ab224b | 2007-12-31 00:11:19 -0800 | [diff] [blame] | 227 | sk_mem_reclaim(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 228 | out_unlock: |
| 229 | bh_unlock_sock(sk); |
| 230 | sock_put(sk); |
| 231 | } |
| 232 | |
| 233 | static void tcp_probe_timer(struct sock *sk) |
| 234 | { |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 235 | struct inet_connection_sock *icsk = inet_csk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 236 | struct tcp_sock *tp = tcp_sk(sk); |
| 237 | int max_probes; |
| 238 | |
David S. Miller | fe067e8 | 2007-03-07 12:12:44 -0800 | [diff] [blame] | 239 | if (tp->packets_out || !tcp_send_head(sk)) { |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 240 | icsk->icsk_probes_out = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 241 | return; |
| 242 | } |
| 243 | |
| 244 | /* *WARNING* RFC 1122 forbids this |
| 245 | * |
| 246 | * It doesn't AFAIK, because we kill the retransmit timer -AK |
| 247 | * |
| 248 | * FIXME: We ought not to do it, Solaris 2.5 actually has fixing |
| 249 | * this behaviour in Solaris down as a bug fix. [AC] |
| 250 | * |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 251 | * Let me to explain. icsk_probes_out is zeroed by incoming ACKs |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 252 | * even if they advertise zero window. Hence, connection is killed only |
| 253 | * if we received no ACKs for normal connection timeout. It is not killed |
| 254 | * only because window stays zero for some time, window may be zero |
| 255 | * until armageddon and even later. We are in full accordance |
| 256 | * with RFCs, only probe timer combines both retransmission timeout |
| 257 | * and probe timeout in one bottle. --ANK |
| 258 | */ |
| 259 | max_probes = sysctl_tcp_retries2; |
| 260 | |
| 261 | if (sock_flag(sk, SOCK_DEAD)) { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 262 | const int alive = ((icsk->icsk_rto << icsk->icsk_backoff) < TCP_RTO_MAX); |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 263 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 264 | max_probes = tcp_orphan_retries(sk, alive); |
| 265 | |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 266 | 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] | 267 | return; |
| 268 | } |
| 269 | |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 270 | if (icsk->icsk_probes_out > max_probes) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 271 | tcp_write_err(sk); |
| 272 | } else { |
| 273 | /* Only send another probe if we didn't close things up. */ |
| 274 | tcp_send_probe0(sk); |
| 275 | } |
| 276 | } |
| 277 | |
| 278 | /* |
| 279 | * The TCP retransmit timer. |
| 280 | */ |
| 281 | |
| 282 | static void tcp_retransmit_timer(struct sock *sk) |
| 283 | { |
| 284 | struct tcp_sock *tp = tcp_sk(sk); |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 285 | struct inet_connection_sock *icsk = inet_csk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 286 | |
| 287 | if (!tp->packets_out) |
| 288 | goto out; |
| 289 | |
David S. Miller | fe067e8 | 2007-03-07 12:12:44 -0800 | [diff] [blame] | 290 | BUG_TRAP(!tcp_write_queue_empty(sk)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 291 | |
| 292 | if (!tp->snd_wnd && !sock_flag(sk, SOCK_DEAD) && |
| 293 | !((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))) { |
| 294 | /* Receiver dastardly shrinks window. Our retransmits |
| 295 | * become zero probes, but we should not timeout this |
| 296 | * connection. If the socket is an orphan, time it out, |
| 297 | * we cannot allow such beasts to hang infinitely. |
| 298 | */ |
| 299 | #ifdef TCP_DEBUG |
YOSHIFUJI Hideaki | 569508c | 2008-04-14 04:09:36 -0700 | [diff] [blame] | 300 | struct inet_sock *inet = inet_sk(sk); |
| 301 | if (sk->sk_family == AF_INET) { |
YOSHIFUJI Hideaki | a7d632b | 2008-04-14 04:09:00 -0700 | [diff] [blame] | 302 | LIMIT_NETDEBUG(KERN_DEBUG "TCP: Treason uncloaked! Peer " NIPQUAD_FMT ":%u/%u shrinks window %u:%u. Repaired.\n", |
Al Viro | 714e85b | 2006-11-14 20:51:49 -0800 | [diff] [blame] | 303 | NIPQUAD(inet->daddr), ntohs(inet->dport), |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 304 | inet->num, tp->snd_una, tp->snd_nxt); |
| 305 | } |
YOSHIFUJI Hideaki | 569508c | 2008-04-14 04:09:36 -0700 | [diff] [blame] | 306 | #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) |
| 307 | else if (sk->sk_family == AF_INET6) { |
| 308 | struct ipv6_pinfo *np = inet6_sk(sk); |
| 309 | LIMIT_NETDEBUG(KERN_DEBUG "TCP: Treason uncloaked! Peer " NIP6_FMT ":%u/%u shrinks window %u:%u. Repaired.\n", |
| 310 | NIP6(np->daddr), ntohs(inet->dport), |
| 311 | inet->num, tp->snd_una, tp->snd_nxt); |
| 312 | } |
| 313 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 314 | #endif |
| 315 | if (tcp_time_stamp - tp->rcv_tstamp > TCP_RTO_MAX) { |
| 316 | tcp_write_err(sk); |
| 317 | goto out; |
| 318 | } |
| 319 | tcp_enter_loss(sk, 0); |
David S. Miller | fe067e8 | 2007-03-07 12:12:44 -0800 | [diff] [blame] | 320 | tcp_retransmit_skb(sk, tcp_write_queue_head(sk)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 321 | __sk_dst_reset(sk); |
| 322 | goto out_reset_timer; |
| 323 | } |
| 324 | |
| 325 | if (tcp_write_timeout(sk)) |
| 326 | goto out; |
| 327 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 328 | if (icsk->icsk_retransmits == 0) { |
Pavel Emelyanov | 40b215e | 2008-07-03 01:05:41 -0700 | [diff] [blame] | 329 | int mib_idx; |
| 330 | |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 331 | if (icsk->icsk_ca_state == TCP_CA_Disorder || |
| 332 | icsk->icsk_ca_state == TCP_CA_Recovery) { |
Ilpo Järvinen | e60402d | 2007-08-09 15:14:46 +0300 | [diff] [blame] | 333 | if (tcp_is_sack(tp)) { |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 334 | if (icsk->icsk_ca_state == TCP_CA_Recovery) |
Pavel Emelyanov | 40b215e | 2008-07-03 01:05:41 -0700 | [diff] [blame] | 335 | mib_idx = LINUX_MIB_TCPSACKRECOVERYFAIL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 336 | else |
Pavel Emelyanov | 40b215e | 2008-07-03 01:05:41 -0700 | [diff] [blame] | 337 | mib_idx = LINUX_MIB_TCPSACKFAILURES; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 338 | } else { |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 339 | if (icsk->icsk_ca_state == TCP_CA_Recovery) |
Pavel Emelyanov | 40b215e | 2008-07-03 01:05:41 -0700 | [diff] [blame] | 340 | mib_idx = LINUX_MIB_TCPRENORECOVERYFAIL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 341 | else |
Pavel Emelyanov | 40b215e | 2008-07-03 01:05:41 -0700 | [diff] [blame] | 342 | mib_idx = LINUX_MIB_TCPRENOFAILURES; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 343 | } |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 344 | } else if (icsk->icsk_ca_state == TCP_CA_Loss) { |
Pavel Emelyanov | 40b215e | 2008-07-03 01:05:41 -0700 | [diff] [blame] | 345 | mib_idx = LINUX_MIB_TCPLOSSFAILURES; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 346 | } else { |
Pavel Emelyanov | 40b215e | 2008-07-03 01:05:41 -0700 | [diff] [blame] | 347 | mib_idx = LINUX_MIB_TCPTIMEOUTS; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 348 | } |
Pavel Emelyanov | 40b215e | 2008-07-03 01:05:41 -0700 | [diff] [blame] | 349 | NET_INC_STATS_BH(mib_idx); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 350 | } |
| 351 | |
| 352 | if (tcp_use_frto(sk)) { |
| 353 | tcp_enter_frto(sk); |
| 354 | } else { |
| 355 | tcp_enter_loss(sk, 0); |
| 356 | } |
| 357 | |
David S. Miller | fe067e8 | 2007-03-07 12:12:44 -0800 | [diff] [blame] | 358 | if (tcp_retransmit_skb(sk, tcp_write_queue_head(sk)) > 0) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 359 | /* Retransmission failed because of local congestion, |
| 360 | * do not backoff. |
| 361 | */ |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 362 | if (!icsk->icsk_retransmits) |
| 363 | icsk->icsk_retransmits = 1; |
| 364 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, |
Arnaldo Carvalho de Melo | 3f421ba | 2005-08-09 20:11:08 -0700 | [diff] [blame] | 365 | min(icsk->icsk_rto, TCP_RESOURCE_PROBE_INTERVAL), |
| 366 | TCP_RTO_MAX); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 367 | goto out; |
| 368 | } |
| 369 | |
| 370 | /* Increase the timeout each time we retransmit. Note that |
| 371 | * we do not increase the rtt estimate. rto is initialized |
| 372 | * from rtt, but increases here. Jacobson (SIGCOMM 88) suggests |
| 373 | * that doubling rto each time is the least we can get away with. |
| 374 | * In KA9Q, Karn uses this for the first few times, and then |
| 375 | * goes to quadratic. netBSD doubles, but only goes up to *64, |
| 376 | * and clamps at 1 to 64 sec afterwards. Note that 120 sec is |
| 377 | * defined in the protocol as the maximum possible RTT. I guess |
| 378 | * we'll have to use something other than TCP to talk to the |
| 379 | * University of Mars. |
| 380 | * |
| 381 | * PAWS allows us longer timeouts and large windows, so once |
| 382 | * implemented ftp to mars will work nicely. We will have to fix |
| 383 | * the 120 second clamps though! |
| 384 | */ |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 385 | icsk->icsk_backoff++; |
| 386 | icsk->icsk_retransmits++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 387 | |
| 388 | out_reset_timer: |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 389 | icsk->icsk_rto = min(icsk->icsk_rto << 1, TCP_RTO_MAX); |
Arnaldo Carvalho de Melo | 3f421ba | 2005-08-09 20:11:08 -0700 | [diff] [blame] | 390 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, icsk->icsk_rto, TCP_RTO_MAX); |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 391 | if (icsk->icsk_retransmits > sysctl_tcp_retries1) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 392 | __sk_dst_reset(sk); |
| 393 | |
| 394 | out:; |
| 395 | } |
| 396 | |
| 397 | static void tcp_write_timer(unsigned long data) |
| 398 | { |
| 399 | struct sock *sk = (struct sock*)data; |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 400 | struct inet_connection_sock *icsk = inet_csk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 401 | int event; |
| 402 | |
| 403 | bh_lock_sock(sk); |
| 404 | if (sock_owned_by_user(sk)) { |
| 405 | /* Try again later */ |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 406 | sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + (HZ / 20)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 407 | goto out_unlock; |
| 408 | } |
| 409 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 410 | if (sk->sk_state == TCP_CLOSE || !icsk->icsk_pending) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 411 | goto out; |
| 412 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 413 | if (time_after(icsk->icsk_timeout, jiffies)) { |
| 414 | sk_reset_timer(sk, &icsk->icsk_retransmit_timer, icsk->icsk_timeout); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 415 | goto out; |
| 416 | } |
| 417 | |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 418 | event = icsk->icsk_pending; |
| 419 | icsk->icsk_pending = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 420 | |
| 421 | switch (event) { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 422 | case ICSK_TIME_RETRANS: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 423 | tcp_retransmit_timer(sk); |
| 424 | break; |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 425 | case ICSK_TIME_PROBE0: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 426 | tcp_probe_timer(sk); |
| 427 | break; |
| 428 | } |
| 429 | TCP_CHECK_TIMER(sk); |
| 430 | |
| 431 | out: |
Hideo Aoki | 3ab224b | 2007-12-31 00:11:19 -0800 | [diff] [blame] | 432 | sk_mem_reclaim(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 433 | out_unlock: |
| 434 | bh_unlock_sock(sk); |
| 435 | sock_put(sk); |
| 436 | } |
| 437 | |
Arnaldo Carvalho de Melo | 295f732 | 2005-08-09 20:11:56 -0700 | [diff] [blame] | 438 | /* |
| 439 | * Timer for listening sockets |
| 440 | */ |
| 441 | |
| 442 | static void tcp_synack_timer(struct sock *sk) |
| 443 | { |
Arnaldo Carvalho de Melo | a019d6f | 2005-08-09 20:15:09 -0700 | [diff] [blame] | 444 | inet_csk_reqsk_queue_prune(sk, TCP_SYNQ_INTERVAL, |
| 445 | TCP_TIMEOUT_INIT, TCP_RTO_MAX); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 446 | } |
| 447 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 448 | void tcp_set_keepalive(struct sock *sk, int val) |
| 449 | { |
| 450 | if ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)) |
| 451 | return; |
| 452 | |
| 453 | if (val && !sock_flag(sk, SOCK_KEEPOPEN)) |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 454 | inet_csk_reset_keepalive_timer(sk, keepalive_time_when(tcp_sk(sk))); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 455 | else if (!val) |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 456 | inet_csk_delete_keepalive_timer(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 457 | } |
| 458 | |
| 459 | |
| 460 | static void tcp_keepalive_timer (unsigned long data) |
| 461 | { |
| 462 | struct sock *sk = (struct sock *) data; |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 463 | struct inet_connection_sock *icsk = inet_csk(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 464 | struct tcp_sock *tp = tcp_sk(sk); |
| 465 | __u32 elapsed; |
| 466 | |
| 467 | /* Only process if socket is not in use. */ |
| 468 | bh_lock_sock(sk); |
| 469 | if (sock_owned_by_user(sk)) { |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 470 | /* Try again later. */ |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 471 | inet_csk_reset_keepalive_timer (sk, HZ/20); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 472 | goto out; |
| 473 | } |
| 474 | |
| 475 | if (sk->sk_state == TCP_LISTEN) { |
| 476 | tcp_synack_timer(sk); |
| 477 | goto out; |
| 478 | } |
| 479 | |
| 480 | if (sk->sk_state == TCP_FIN_WAIT2 && sock_flag(sk, SOCK_DEAD)) { |
| 481 | if (tp->linger2 >= 0) { |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 482 | const int tmo = tcp_fin_time(sk) - TCP_TIMEWAIT_LEN; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 483 | |
| 484 | if (tmo > 0) { |
| 485 | tcp_time_wait(sk, TCP_FIN_WAIT2, tmo); |
| 486 | goto out; |
| 487 | } |
| 488 | } |
| 489 | tcp_send_active_reset(sk, GFP_ATOMIC); |
| 490 | goto death; |
| 491 | } |
| 492 | |
| 493 | if (!sock_flag(sk, SOCK_KEEPOPEN) || sk->sk_state == TCP_CLOSE) |
| 494 | goto out; |
| 495 | |
| 496 | elapsed = keepalive_time_when(tp); |
| 497 | |
| 498 | /* It is alive without keepalive 8) */ |
David S. Miller | fe067e8 | 2007-03-07 12:12:44 -0800 | [diff] [blame] | 499 | if (tp->packets_out || tcp_send_head(sk)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 500 | goto resched; |
| 501 | |
| 502 | elapsed = tcp_time_stamp - tp->rcv_tstamp; |
| 503 | |
| 504 | if (elapsed >= keepalive_time_when(tp)) { |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 505 | if ((!tp->keepalive_probes && icsk->icsk_probes_out >= sysctl_tcp_keepalive_probes) || |
| 506 | (tp->keepalive_probes && icsk->icsk_probes_out >= tp->keepalive_probes)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 507 | tcp_send_active_reset(sk, GFP_ATOMIC); |
| 508 | tcp_write_err(sk); |
| 509 | goto out; |
| 510 | } |
| 511 | if (tcp_write_wakeup(sk) <= 0) { |
Arnaldo Carvalho de Melo | 6687e98 | 2005-08-10 04:03:31 -0300 | [diff] [blame] | 512 | icsk->icsk_probes_out++; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 513 | elapsed = keepalive_intvl_when(tp); |
| 514 | } else { |
| 515 | /* If keepalive was lost due to local congestion, |
| 516 | * try harder. |
| 517 | */ |
| 518 | elapsed = TCP_RESOURCE_PROBE_INTERVAL; |
| 519 | } |
| 520 | } else { |
| 521 | /* It is tp->rcv_tstamp + keepalive_time_when(tp) */ |
| 522 | elapsed = keepalive_time_when(tp) - elapsed; |
| 523 | } |
| 524 | |
| 525 | TCP_CHECK_TIMER(sk); |
Hideo Aoki | 3ab224b | 2007-12-31 00:11:19 -0800 | [diff] [blame] | 526 | sk_mem_reclaim(sk); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 527 | |
| 528 | resched: |
Arnaldo Carvalho de Melo | 463c84b | 2005-08-09 20:10:42 -0700 | [diff] [blame] | 529 | inet_csk_reset_keepalive_timer (sk, elapsed); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 530 | goto out; |
| 531 | |
YOSHIFUJI Hideaki | e905a9e | 2007-02-09 23:24:47 +0900 | [diff] [blame] | 532 | death: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 533 | tcp_done(sk); |
| 534 | |
| 535 | out: |
| 536 | bh_unlock_sock(sk); |
| 537 | sock_put(sk); |
| 538 | } |