Commit | Line | Data |
---|---|---|
1da177e4 LT |
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 | * | |
8 | * Version: $Id: tcp_timer.c,v 1.88 2002/02/01 22:01:04 davem Exp $ | |
9 | * | |
02c30a84 | 10 | * Authors: Ross Biro |
1da177e4 LT |
11 | * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG> |
12 | * Mark Evans, <evansmp@uhura.aston.ac.uk> | |
13 | * Corey Minyard <wf-rch!minyard@relay.EU.net> | |
14 | * Florian La Roche, <flla@stud.uni-sb.de> | |
15 | * Charles Hedrick, <hedrick@klinzhai.rutgers.edu> | |
16 | * Linus Torvalds, <torvalds@cs.helsinki.fi> | |
17 | * Alan Cox, <gw4pts@gw4pts.ampr.org> | |
18 | * Matthew Dillon, <dillon@apollo.west.oic.com> | |
19 | * Arnt Gulbrandsen, <agulbra@nvg.unit.no> | |
20 | * Jorge Cwik, <jorge@laser.satlink.net> | |
21 | */ | |
22 | ||
23 | #include <linux/module.h> | |
24 | #include <net/tcp.h> | |
25 | ||
ab32ea5d BH |
26 | int sysctl_tcp_syn_retries __read_mostly = TCP_SYN_RETRIES; |
27 | int sysctl_tcp_synack_retries __read_mostly = TCP_SYNACK_RETRIES; | |
28 | int sysctl_tcp_keepalive_time __read_mostly = TCP_KEEPALIVE_TIME; | |
29 | int sysctl_tcp_keepalive_probes __read_mostly = TCP_KEEPALIVE_PROBES; | |
30 | int sysctl_tcp_keepalive_intvl __read_mostly = TCP_KEEPALIVE_INTVL; | |
31 | int sysctl_tcp_retries1 __read_mostly = TCP_RETR1; | |
32 | int sysctl_tcp_retries2 __read_mostly = TCP_RETR2; | |
33 | int sysctl_tcp_orphan_retries __read_mostly; | |
1da177e4 LT |
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 | ||
463c84b9 ACM |
39 | void tcp_init_xmit_timers(struct sock *sk) |
40 | { | |
41 | inet_csk_init_xmit_timers(sk, &tcp_write_timer, &tcp_delack_timer, | |
42 | &tcp_keepalive_timer); | |
43 | } | |
44 | ||
3f421baa ACM |
45 | EXPORT_SYMBOL(tcp_init_xmit_timers); |
46 | ||
1da177e4 LT |
47 | static void tcp_write_err(struct sock *sk) |
48 | { | |
49 | sk->sk_err = sk->sk_err_soft ? : ETIMEDOUT; | |
50 | sk->sk_error_report(sk); | |
51 | ||
52 | tcp_done(sk); | |
53 | NET_INC_STATS_BH(LINUX_MIB_TCPABORTONTIMEOUT); | |
54 | } | |
55 | ||
56 | /* Do not allow orphaned sockets to eat all our resources. | |
57 | * This is direct violation of TCP specs, but it is required | |
58 | * to prevent DoS attacks. It is called when a retransmission timeout | |
59 | * or zero probe timeout occurs on orphaned socket. | |
60 | * | |
caa20d9a | 61 | * Criteria is still not confirmed experimentally and may change. |
1da177e4 LT |
62 | * We kill the socket, if: |
63 | * 1. If number of orphaned sockets exceeds an administratively configured | |
64 | * limit. | |
65 | * 2. If we have strong memory pressure. | |
66 | */ | |
67 | static int tcp_out_of_resources(struct sock *sk, int do_reset) | |
68 | { | |
69 | struct tcp_sock *tp = tcp_sk(sk); | |
70 | int orphans = atomic_read(&tcp_orphan_count); | |
71 | ||
e905a9ed | 72 | /* If peer does not open window for long time, or did not transmit |
1da177e4 LT |
73 | * anything for long time, penalize it. */ |
74 | if ((s32)(tcp_time_stamp - tp->lsndtime) > 2*TCP_RTO_MAX || !do_reset) | |
75 | orphans <<= 1; | |
76 | ||
77 | /* If some dubious ICMP arrived, penalize even more. */ | |
78 | if (sk->sk_err_soft) | |
79 | orphans <<= 1; | |
80 | ||
e4fd5da3 | 81 | if (tcp_too_many_orphans(sk, orphans)) { |
1da177e4 LT |
82 | if (net_ratelimit()) |
83 | printk(KERN_INFO "Out of socket memory\n"); | |
84 | ||
85 | /* Catch exceptional cases, when connection requires reset. | |
86 | * 1. Last segment was sent recently. */ | |
87 | if ((s32)(tcp_time_stamp - tp->lsndtime) <= TCP_TIMEWAIT_LEN || | |
88 | /* 2. Window is closed. */ | |
89 | (!tp->snd_wnd && !tp->packets_out)) | |
90 | do_reset = 1; | |
91 | if (do_reset) | |
92 | tcp_send_active_reset(sk, GFP_ATOMIC); | |
93 | tcp_done(sk); | |
94 | NET_INC_STATS_BH(LINUX_MIB_TCPABORTONMEMORY); | |
95 | return 1; | |
96 | } | |
97 | return 0; | |
98 | } | |
99 | ||
100 | /* Calculate maximal number or retries on an orphaned socket. */ | |
101 | static int tcp_orphan_retries(struct sock *sk, int alive) | |
102 | { | |
103 | int retries = sysctl_tcp_orphan_retries; /* May be zero. */ | |
104 | ||
105 | /* We know from an ICMP that something is wrong. */ | |
106 | if (sk->sk_err_soft && !alive) | |
107 | retries = 0; | |
108 | ||
109 | /* However, if socket sent something recently, select some safe | |
110 | * number of retries. 8 corresponds to >100 seconds with minimal | |
111 | * RTO of 200msec. */ | |
112 | if (retries == 0 && alive) | |
113 | retries = 8; | |
114 | return retries; | |
115 | } | |
116 | ||
117 | /* A write timeout has occurred. Process the after effects. */ | |
118 | static int tcp_write_timeout(struct sock *sk) | |
119 | { | |
5d424d5a JH |
120 | struct inet_connection_sock *icsk = inet_csk(sk); |
121 | struct tcp_sock *tp = tcp_sk(sk); | |
1da177e4 | 122 | int retry_until; |
5d424d5a | 123 | int mss; |
1da177e4 LT |
124 | |
125 | if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) { | |
463c84b9 | 126 | if (icsk->icsk_retransmits) |
1da177e4 | 127 | dst_negative_advice(&sk->sk_dst_cache); |
463c84b9 | 128 | retry_until = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries; |
1da177e4 | 129 | } else { |
463c84b9 | 130 | if (icsk->icsk_retransmits >= sysctl_tcp_retries1) { |
5d424d5a JH |
131 | /* Black hole detection */ |
132 | if (sysctl_tcp_mtu_probing) { | |
133 | if (!icsk->icsk_mtup.enabled) { | |
134 | icsk->icsk_mtup.enabled = 1; | |
135 | tcp_sync_mss(sk, icsk->icsk_pmtu_cookie); | |
136 | } else { | |
137 | mss = min(sysctl_tcp_base_mss, | |
e905a9ed | 138 | tcp_mtu_to_mss(sk, icsk->icsk_mtup.search_low)/2); |
5d424d5a JH |
139 | mss = max(mss, 68 - tp->tcp_header_len); |
140 | icsk->icsk_mtup.search_low = tcp_mss_to_mtu(sk, mss); | |
141 | tcp_sync_mss(sk, icsk->icsk_pmtu_cookie); | |
142 | } | |
143 | } | |
1da177e4 LT |
144 | |
145 | dst_negative_advice(&sk->sk_dst_cache); | |
146 | } | |
147 | ||
148 | retry_until = sysctl_tcp_retries2; | |
149 | if (sock_flag(sk, SOCK_DEAD)) { | |
463c84b9 | 150 | const int alive = (icsk->icsk_rto < TCP_RTO_MAX); |
e905a9ed | 151 | |
1da177e4 LT |
152 | retry_until = tcp_orphan_retries(sk, alive); |
153 | ||
463c84b9 | 154 | if (tcp_out_of_resources(sk, alive || icsk->icsk_retransmits < retry_until)) |
1da177e4 LT |
155 | return 1; |
156 | } | |
157 | } | |
158 | ||
463c84b9 | 159 | if (icsk->icsk_retransmits >= retry_until) { |
1da177e4 LT |
160 | /* Has it gone just too far? */ |
161 | tcp_write_err(sk); | |
162 | return 1; | |
163 | } | |
164 | return 0; | |
165 | } | |
166 | ||
167 | static void tcp_delack_timer(unsigned long data) | |
168 | { | |
169 | struct sock *sk = (struct sock*)data; | |
170 | struct tcp_sock *tp = tcp_sk(sk); | |
463c84b9 | 171 | struct inet_connection_sock *icsk = inet_csk(sk); |
1da177e4 LT |
172 | |
173 | bh_lock_sock(sk); | |
174 | if (sock_owned_by_user(sk)) { | |
175 | /* Try again later. */ | |
463c84b9 | 176 | icsk->icsk_ack.blocked = 1; |
1da177e4 | 177 | NET_INC_STATS_BH(LINUX_MIB_DELAYEDACKLOCKED); |
463c84b9 | 178 | sk_reset_timer(sk, &icsk->icsk_delack_timer, jiffies + TCP_DELACK_MIN); |
1da177e4 LT |
179 | goto out_unlock; |
180 | } | |
181 | ||
182 | sk_stream_mem_reclaim(sk); | |
183 | ||
463c84b9 | 184 | if (sk->sk_state == TCP_CLOSE || !(icsk->icsk_ack.pending & ICSK_ACK_TIMER)) |
1da177e4 LT |
185 | goto out; |
186 | ||
463c84b9 ACM |
187 | if (time_after(icsk->icsk_ack.timeout, jiffies)) { |
188 | sk_reset_timer(sk, &icsk->icsk_delack_timer, icsk->icsk_ack.timeout); | |
1da177e4 LT |
189 | goto out; |
190 | } | |
463c84b9 | 191 | icsk->icsk_ack.pending &= ~ICSK_ACK_TIMER; |
1da177e4 | 192 | |
b03efcfb | 193 | if (!skb_queue_empty(&tp->ucopy.prequeue)) { |
1da177e4 LT |
194 | struct sk_buff *skb; |
195 | ||
b03efcfb | 196 | NET_INC_STATS_BH(LINUX_MIB_TCPSCHEDULERFAILED); |
1da177e4 LT |
197 | |
198 | while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) | |
199 | sk->sk_backlog_rcv(sk, skb); | |
200 | ||
201 | tp->ucopy.memory = 0; | |
202 | } | |
203 | ||
463c84b9 ACM |
204 | if (inet_csk_ack_scheduled(sk)) { |
205 | if (!icsk->icsk_ack.pingpong) { | |
1da177e4 | 206 | /* Delayed ACK missed: inflate ATO. */ |
463c84b9 | 207 | icsk->icsk_ack.ato = min(icsk->icsk_ack.ato << 1, icsk->icsk_rto); |
1da177e4 LT |
208 | } else { |
209 | /* Delayed ACK missed: leave pingpong mode and | |
210 | * deflate ATO. | |
211 | */ | |
463c84b9 ACM |
212 | icsk->icsk_ack.pingpong = 0; |
213 | icsk->icsk_ack.ato = TCP_ATO_MIN; | |
1da177e4 LT |
214 | } |
215 | tcp_send_ack(sk); | |
216 | NET_INC_STATS_BH(LINUX_MIB_DELAYEDACKS); | |
217 | } | |
218 | TCP_CHECK_TIMER(sk); | |
219 | ||
220 | out: | |
221 | if (tcp_memory_pressure) | |
222 | sk_stream_mem_reclaim(sk); | |
223 | out_unlock: | |
224 | bh_unlock_sock(sk); | |
225 | sock_put(sk); | |
226 | } | |
227 | ||
228 | static void tcp_probe_timer(struct sock *sk) | |
229 | { | |
6687e988 | 230 | struct inet_connection_sock *icsk = inet_csk(sk); |
1da177e4 LT |
231 | struct tcp_sock *tp = tcp_sk(sk); |
232 | int max_probes; | |
233 | ||
fe067e8a | 234 | if (tp->packets_out || !tcp_send_head(sk)) { |
6687e988 | 235 | icsk->icsk_probes_out = 0; |
1da177e4 LT |
236 | return; |
237 | } | |
238 | ||
239 | /* *WARNING* RFC 1122 forbids this | |
240 | * | |
241 | * It doesn't AFAIK, because we kill the retransmit timer -AK | |
242 | * | |
243 | * FIXME: We ought not to do it, Solaris 2.5 actually has fixing | |
244 | * this behaviour in Solaris down as a bug fix. [AC] | |
245 | * | |
6687e988 | 246 | * Let me to explain. icsk_probes_out is zeroed by incoming ACKs |
1da177e4 LT |
247 | * even if they advertise zero window. Hence, connection is killed only |
248 | * if we received no ACKs for normal connection timeout. It is not killed | |
249 | * only because window stays zero for some time, window may be zero | |
250 | * until armageddon and even later. We are in full accordance | |
251 | * with RFCs, only probe timer combines both retransmission timeout | |
252 | * and probe timeout in one bottle. --ANK | |
253 | */ | |
254 | max_probes = sysctl_tcp_retries2; | |
255 | ||
256 | if (sock_flag(sk, SOCK_DEAD)) { | |
463c84b9 | 257 | const int alive = ((icsk->icsk_rto << icsk->icsk_backoff) < TCP_RTO_MAX); |
e905a9ed | 258 | |
1da177e4 LT |
259 | max_probes = tcp_orphan_retries(sk, alive); |
260 | ||
6687e988 | 261 | if (tcp_out_of_resources(sk, alive || icsk->icsk_probes_out <= max_probes)) |
1da177e4 LT |
262 | return; |
263 | } | |
264 | ||
6687e988 | 265 | if (icsk->icsk_probes_out > max_probes) { |
1da177e4 LT |
266 | tcp_write_err(sk); |
267 | } else { | |
268 | /* Only send another probe if we didn't close things up. */ | |
269 | tcp_send_probe0(sk); | |
270 | } | |
271 | } | |
272 | ||
273 | /* | |
274 | * The TCP retransmit timer. | |
275 | */ | |
276 | ||
277 | static void tcp_retransmit_timer(struct sock *sk) | |
278 | { | |
279 | struct tcp_sock *tp = tcp_sk(sk); | |
463c84b9 | 280 | struct inet_connection_sock *icsk = inet_csk(sk); |
1da177e4 LT |
281 | |
282 | if (!tp->packets_out) | |
283 | goto out; | |
284 | ||
fe067e8a | 285 | BUG_TRAP(!tcp_write_queue_empty(sk)); |
1da177e4 LT |
286 | |
287 | if (!tp->snd_wnd && !sock_flag(sk, SOCK_DEAD) && | |
288 | !((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))) { | |
289 | /* Receiver dastardly shrinks window. Our retransmits | |
290 | * become zero probes, but we should not timeout this | |
291 | * connection. If the socket is an orphan, time it out, | |
292 | * we cannot allow such beasts to hang infinitely. | |
293 | */ | |
294 | #ifdef TCP_DEBUG | |
274707cf | 295 | if (1) { |
1da177e4 | 296 | struct inet_sock *inet = inet_sk(sk); |
274707cf | 297 | LIMIT_NETDEBUG(KERN_DEBUG "TCP: Treason uncloaked! Peer %u.%u.%u.%u:%u/%u shrinks window %u:%u. Repaired.\n", |
714e85be | 298 | NIPQUAD(inet->daddr), ntohs(inet->dport), |
1da177e4 LT |
299 | inet->num, tp->snd_una, tp->snd_nxt); |
300 | } | |
301 | #endif | |
302 | if (tcp_time_stamp - tp->rcv_tstamp > TCP_RTO_MAX) { | |
303 | tcp_write_err(sk); | |
304 | goto out; | |
305 | } | |
306 | tcp_enter_loss(sk, 0); | |
fe067e8a | 307 | tcp_retransmit_skb(sk, tcp_write_queue_head(sk)); |
1da177e4 LT |
308 | __sk_dst_reset(sk); |
309 | goto out_reset_timer; | |
310 | } | |
311 | ||
312 | if (tcp_write_timeout(sk)) | |
313 | goto out; | |
314 | ||
463c84b9 | 315 | if (icsk->icsk_retransmits == 0) { |
6687e988 ACM |
316 | if (icsk->icsk_ca_state == TCP_CA_Disorder || |
317 | icsk->icsk_ca_state == TCP_CA_Recovery) { | |
1da177e4 | 318 | if (tp->rx_opt.sack_ok) { |
6687e988 | 319 | if (icsk->icsk_ca_state == TCP_CA_Recovery) |
1da177e4 LT |
320 | NET_INC_STATS_BH(LINUX_MIB_TCPSACKRECOVERYFAIL); |
321 | else | |
322 | NET_INC_STATS_BH(LINUX_MIB_TCPSACKFAILURES); | |
323 | } else { | |
6687e988 | 324 | if (icsk->icsk_ca_state == TCP_CA_Recovery) |
1da177e4 LT |
325 | NET_INC_STATS_BH(LINUX_MIB_TCPRENORECOVERYFAIL); |
326 | else | |
327 | NET_INC_STATS_BH(LINUX_MIB_TCPRENOFAILURES); | |
328 | } | |
6687e988 | 329 | } else if (icsk->icsk_ca_state == TCP_CA_Loss) { |
1da177e4 LT |
330 | NET_INC_STATS_BH(LINUX_MIB_TCPLOSSFAILURES); |
331 | } else { | |
332 | NET_INC_STATS_BH(LINUX_MIB_TCPTIMEOUTS); | |
333 | } | |
334 | } | |
335 | ||
336 | if (tcp_use_frto(sk)) { | |
337 | tcp_enter_frto(sk); | |
338 | } else { | |
339 | tcp_enter_loss(sk, 0); | |
340 | } | |
341 | ||
fe067e8a | 342 | if (tcp_retransmit_skb(sk, tcp_write_queue_head(sk)) > 0) { |
1da177e4 LT |
343 | /* Retransmission failed because of local congestion, |
344 | * do not backoff. | |
345 | */ | |
463c84b9 ACM |
346 | if (!icsk->icsk_retransmits) |
347 | icsk->icsk_retransmits = 1; | |
348 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, | |
3f421baa ACM |
349 | min(icsk->icsk_rto, TCP_RESOURCE_PROBE_INTERVAL), |
350 | TCP_RTO_MAX); | |
1da177e4 LT |
351 | goto out; |
352 | } | |
353 | ||
354 | /* Increase the timeout each time we retransmit. Note that | |
355 | * we do not increase the rtt estimate. rto is initialized | |
356 | * from rtt, but increases here. Jacobson (SIGCOMM 88) suggests | |
357 | * that doubling rto each time is the least we can get away with. | |
358 | * In KA9Q, Karn uses this for the first few times, and then | |
359 | * goes to quadratic. netBSD doubles, but only goes up to *64, | |
360 | * and clamps at 1 to 64 sec afterwards. Note that 120 sec is | |
361 | * defined in the protocol as the maximum possible RTT. I guess | |
362 | * we'll have to use something other than TCP to talk to the | |
363 | * University of Mars. | |
364 | * | |
365 | * PAWS allows us longer timeouts and large windows, so once | |
366 | * implemented ftp to mars will work nicely. We will have to fix | |
367 | * the 120 second clamps though! | |
368 | */ | |
463c84b9 ACM |
369 | icsk->icsk_backoff++; |
370 | icsk->icsk_retransmits++; | |
1da177e4 LT |
371 | |
372 | out_reset_timer: | |
463c84b9 | 373 | icsk->icsk_rto = min(icsk->icsk_rto << 1, TCP_RTO_MAX); |
3f421baa | 374 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, icsk->icsk_rto, TCP_RTO_MAX); |
463c84b9 | 375 | if (icsk->icsk_retransmits > sysctl_tcp_retries1) |
1da177e4 LT |
376 | __sk_dst_reset(sk); |
377 | ||
378 | out:; | |
379 | } | |
380 | ||
381 | static void tcp_write_timer(unsigned long data) | |
382 | { | |
383 | struct sock *sk = (struct sock*)data; | |
463c84b9 | 384 | struct inet_connection_sock *icsk = inet_csk(sk); |
1da177e4 LT |
385 | int event; |
386 | ||
387 | bh_lock_sock(sk); | |
388 | if (sock_owned_by_user(sk)) { | |
389 | /* Try again later */ | |
463c84b9 | 390 | sk_reset_timer(sk, &icsk->icsk_retransmit_timer, jiffies + (HZ / 20)); |
1da177e4 LT |
391 | goto out_unlock; |
392 | } | |
393 | ||
463c84b9 | 394 | if (sk->sk_state == TCP_CLOSE || !icsk->icsk_pending) |
1da177e4 LT |
395 | goto out; |
396 | ||
463c84b9 ACM |
397 | if (time_after(icsk->icsk_timeout, jiffies)) { |
398 | sk_reset_timer(sk, &icsk->icsk_retransmit_timer, icsk->icsk_timeout); | |
1da177e4 LT |
399 | goto out; |
400 | } | |
401 | ||
463c84b9 ACM |
402 | event = icsk->icsk_pending; |
403 | icsk->icsk_pending = 0; | |
1da177e4 LT |
404 | |
405 | switch (event) { | |
463c84b9 | 406 | case ICSK_TIME_RETRANS: |
1da177e4 LT |
407 | tcp_retransmit_timer(sk); |
408 | break; | |
463c84b9 | 409 | case ICSK_TIME_PROBE0: |
1da177e4 LT |
410 | tcp_probe_timer(sk); |
411 | break; | |
412 | } | |
413 | TCP_CHECK_TIMER(sk); | |
414 | ||
415 | out: | |
416 | sk_stream_mem_reclaim(sk); | |
417 | out_unlock: | |
418 | bh_unlock_sock(sk); | |
419 | sock_put(sk); | |
420 | } | |
421 | ||
295f7324 ACM |
422 | /* |
423 | * Timer for listening sockets | |
424 | */ | |
425 | ||
426 | static void tcp_synack_timer(struct sock *sk) | |
427 | { | |
a019d6fe ACM |
428 | inet_csk_reqsk_queue_prune(sk, TCP_SYNQ_INTERVAL, |
429 | TCP_TIMEOUT_INIT, TCP_RTO_MAX); | |
1da177e4 LT |
430 | } |
431 | ||
1da177e4 LT |
432 | void tcp_set_keepalive(struct sock *sk, int val) |
433 | { | |
434 | if ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)) | |
435 | return; | |
436 | ||
437 | if (val && !sock_flag(sk, SOCK_KEEPOPEN)) | |
463c84b9 | 438 | inet_csk_reset_keepalive_timer(sk, keepalive_time_when(tcp_sk(sk))); |
1da177e4 | 439 | else if (!val) |
463c84b9 | 440 | inet_csk_delete_keepalive_timer(sk); |
1da177e4 LT |
441 | } |
442 | ||
443 | ||
444 | static void tcp_keepalive_timer (unsigned long data) | |
445 | { | |
446 | struct sock *sk = (struct sock *) data; | |
6687e988 | 447 | struct inet_connection_sock *icsk = inet_csk(sk); |
1da177e4 LT |
448 | struct tcp_sock *tp = tcp_sk(sk); |
449 | __u32 elapsed; | |
450 | ||
451 | /* Only process if socket is not in use. */ | |
452 | bh_lock_sock(sk); | |
453 | if (sock_owned_by_user(sk)) { | |
e905a9ed | 454 | /* Try again later. */ |
463c84b9 | 455 | inet_csk_reset_keepalive_timer (sk, HZ/20); |
1da177e4 LT |
456 | goto out; |
457 | } | |
458 | ||
459 | if (sk->sk_state == TCP_LISTEN) { | |
460 | tcp_synack_timer(sk); | |
461 | goto out; | |
462 | } | |
463 | ||
464 | if (sk->sk_state == TCP_FIN_WAIT2 && sock_flag(sk, SOCK_DEAD)) { | |
465 | if (tp->linger2 >= 0) { | |
463c84b9 | 466 | const int tmo = tcp_fin_time(sk) - TCP_TIMEWAIT_LEN; |
1da177e4 LT |
467 | |
468 | if (tmo > 0) { | |
469 | tcp_time_wait(sk, TCP_FIN_WAIT2, tmo); | |
470 | goto out; | |
471 | } | |
472 | } | |
473 | tcp_send_active_reset(sk, GFP_ATOMIC); | |
474 | goto death; | |
475 | } | |
476 | ||
477 | if (!sock_flag(sk, SOCK_KEEPOPEN) || sk->sk_state == TCP_CLOSE) | |
478 | goto out; | |
479 | ||
480 | elapsed = keepalive_time_when(tp); | |
481 | ||
482 | /* It is alive without keepalive 8) */ | |
fe067e8a | 483 | if (tp->packets_out || tcp_send_head(sk)) |
1da177e4 LT |
484 | goto resched; |
485 | ||
486 | elapsed = tcp_time_stamp - tp->rcv_tstamp; | |
487 | ||
488 | if (elapsed >= keepalive_time_when(tp)) { | |
6687e988 ACM |
489 | if ((!tp->keepalive_probes && icsk->icsk_probes_out >= sysctl_tcp_keepalive_probes) || |
490 | (tp->keepalive_probes && icsk->icsk_probes_out >= tp->keepalive_probes)) { | |
1da177e4 LT |
491 | tcp_send_active_reset(sk, GFP_ATOMIC); |
492 | tcp_write_err(sk); | |
493 | goto out; | |
494 | } | |
495 | if (tcp_write_wakeup(sk) <= 0) { | |
6687e988 | 496 | icsk->icsk_probes_out++; |
1da177e4 LT |
497 | elapsed = keepalive_intvl_when(tp); |
498 | } else { | |
499 | /* If keepalive was lost due to local congestion, | |
500 | * try harder. | |
501 | */ | |
502 | elapsed = TCP_RESOURCE_PROBE_INTERVAL; | |
503 | } | |
504 | } else { | |
505 | /* It is tp->rcv_tstamp + keepalive_time_when(tp) */ | |
506 | elapsed = keepalive_time_when(tp) - elapsed; | |
507 | } | |
508 | ||
509 | TCP_CHECK_TIMER(sk); | |
510 | sk_stream_mem_reclaim(sk); | |
511 | ||
512 | resched: | |
463c84b9 | 513 | inet_csk_reset_keepalive_timer (sk, elapsed); |
1da177e4 LT |
514 | goto out; |
515 | ||
e905a9ed | 516 | death: |
1da177e4 LT |
517 | tcp_done(sk); |
518 | ||
519 | out: | |
520 | bh_unlock_sock(sk); | |
521 | sock_put(sk); | |
522 | } |