Commit | Line | Data |
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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 | * | |
02c30a84 | 8 | * Authors: Ross Biro |
1da177e4 LT |
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> | |
5a0e3ad6 | 22 | #include <linux/gfp.h> |
1da177e4 LT |
23 | #include <net/tcp.h> |
24 | ||
ab32ea5d BH |
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; | |
36e31b0a | 33 | int sysctl_tcp_thin_linear_timeouts __read_mostly; |
6fa3eb70 S |
34 | int sysctl_tcp_rto_min __read_mostly = TCP_RTO_MIN; |
35 | EXPORT_SYMBOL(sysctl_tcp_rto_min); | |
36 | int sysctl_tcp_rto_max __read_mostly = TCP_RTO_MAX; | |
37 | EXPORT_SYMBOL(sysctl_tcp_rto_max); | |
1da177e4 | 38 | |
1da177e4 LT |
39 | static void tcp_write_err(struct sock *sk) |
40 | { | |
41 | sk->sk_err = sk->sk_err_soft ? : ETIMEDOUT; | |
42 | sk->sk_error_report(sk); | |
43 | ||
44 | tcp_done(sk); | |
de0744af | 45 | NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPABORTONTIMEOUT); |
1da177e4 LT |
46 | } |
47 | ||
48 | /* Do not allow orphaned sockets to eat all our resources. | |
49 | * This is direct violation of TCP specs, but it is required | |
50 | * to prevent DoS attacks. It is called when a retransmission timeout | |
51 | * or zero probe timeout occurs on orphaned socket. | |
52 | * | |
caa20d9a | 53 | * Criteria is still not confirmed experimentally and may change. |
1da177e4 LT |
54 | * We kill the socket, if: |
55 | * 1. If number of orphaned sockets exceeds an administratively configured | |
56 | * limit. | |
57 | * 2. If we have strong memory pressure. | |
58 | */ | |
59 | static int tcp_out_of_resources(struct sock *sk, int do_reset) | |
60 | { | |
61 | struct tcp_sock *tp = tcp_sk(sk); | |
ad1af0fe | 62 | int shift = 0; |
1da177e4 | 63 | |
e905a9ed | 64 | /* If peer does not open window for long time, or did not transmit |
1da177e4 | 65 | * anything for long time, penalize it. */ |
6fa3eb70 | 66 | if ((s32)(tcp_time_stamp - tp->lsndtime) > 2*sysctl_tcp_rto_max || !do_reset) |
ad1af0fe | 67 | shift++; |
1da177e4 LT |
68 | |
69 | /* If some dubious ICMP arrived, penalize even more. */ | |
70 | if (sk->sk_err_soft) | |
ad1af0fe | 71 | shift++; |
1da177e4 | 72 | |
efcdbf24 | 73 | if (tcp_check_oom(sk, shift)) { |
1da177e4 LT |
74 | /* Catch exceptional cases, when connection requires reset. |
75 | * 1. Last segment was sent recently. */ | |
76 | if ((s32)(tcp_time_stamp - tp->lsndtime) <= TCP_TIMEWAIT_LEN || | |
77 | /* 2. Window is closed. */ | |
78 | (!tp->snd_wnd && !tp->packets_out)) | |
79 | do_reset = 1; | |
80 | if (do_reset) | |
81 | tcp_send_active_reset(sk, GFP_ATOMIC); | |
82 | tcp_done(sk); | |
de0744af | 83 | NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPABORTONMEMORY); |
1da177e4 LT |
84 | return 1; |
85 | } | |
86 | return 0; | |
87 | } | |
88 | ||
89 | /* Calculate maximal number or retries on an orphaned socket. */ | |
90 | static int tcp_orphan_retries(struct sock *sk, int alive) | |
91 | { | |
92 | int retries = sysctl_tcp_orphan_retries; /* May be zero. */ | |
93 | ||
94 | /* We know from an ICMP that something is wrong. */ | |
95 | if (sk->sk_err_soft && !alive) | |
96 | retries = 0; | |
97 | ||
98 | /* However, if socket sent something recently, select some safe | |
99 | * number of retries. 8 corresponds to >100 seconds with minimal | |
100 | * RTO of 200msec. */ | |
101 | if (retries == 0 && alive) | |
102 | retries = 8; | |
103 | return retries; | |
104 | } | |
105 | ||
ce55dd36 ED |
106 | static void tcp_mtu_probing(struct inet_connection_sock *icsk, struct sock *sk) |
107 | { | |
ce55dd36 ED |
108 | /* Black hole detection */ |
109 | if (sysctl_tcp_mtu_probing) { | |
110 | if (!icsk->icsk_mtup.enabled) { | |
111 | icsk->icsk_mtup.enabled = 1; | |
112 | tcp_sync_mss(sk, icsk->icsk_pmtu_cookie); | |
113 | } else { | |
114 | struct tcp_sock *tp = tcp_sk(sk); | |
829942c1 DM |
115 | int mss; |
116 | ||
8beb5c5f | 117 | mss = tcp_mtu_to_mss(sk, icsk->icsk_mtup.search_low) >> 1; |
ce55dd36 ED |
118 | mss = min(sysctl_tcp_base_mss, mss); |
119 | mss = max(mss, 68 - tp->tcp_header_len); | |
120 | icsk->icsk_mtup.search_low = tcp_mss_to_mtu(sk, mss); | |
121 | tcp_sync_mss(sk, icsk->icsk_pmtu_cookie); | |
122 | } | |
123 | } | |
124 | } | |
125 | ||
2f7de571 | 126 | /* This function calculates a "timeout" which is equivalent to the timeout of a |
3ad2f3fb | 127 | * TCP connection after "boundary" unsuccessful, exponentially backed-off |
4d22f7d3 DL |
128 | * retransmissions with an initial RTO of TCP_RTO_MIN or TCP_TIMEOUT_INIT if |
129 | * syn_set flag is set. | |
2f7de571 DL |
130 | */ |
131 | static bool retransmits_timed_out(struct sock *sk, | |
dca43c75 | 132 | unsigned int boundary, |
21a180cd | 133 | unsigned int timeout, |
4d22f7d3 | 134 | bool syn_set) |
2f7de571 | 135 | { |
dca43c75 | 136 | unsigned int linear_backoff_thresh, start_ts; |
6fa3eb70 | 137 | unsigned int rto_base = syn_set ? TCP_TIMEOUT_INIT : sysctl_tcp_rto_min; |
2f7de571 DL |
138 | |
139 | if (!inet_csk(sk)->icsk_retransmits) | |
140 | return false; | |
141 | ||
142 | if (unlikely(!tcp_sk(sk)->retrans_stamp)) | |
143 | start_ts = TCP_SKB_CB(tcp_write_queue_head(sk))->when; | |
144 | else | |
145 | start_ts = tcp_sk(sk)->retrans_stamp; | |
146 | ||
dca43c75 | 147 | if (likely(timeout == 0)) { |
6fa3eb70 | 148 | linear_backoff_thresh = ilog2(sysctl_tcp_rto_max/rto_base); |
2f7de571 | 149 | |
dca43c75 | 150 | if (boundary <= linear_backoff_thresh) |
21a180cd | 151 | timeout = ((2 << boundary) - 1) * rto_base; |
dca43c75 | 152 | else |
21a180cd | 153 | timeout = ((2 << linear_backoff_thresh) - 1) * rto_base + |
6fa3eb70 | 154 | (boundary - linear_backoff_thresh) * sysctl_tcp_rto_max; |
dca43c75 | 155 | } |
2f7de571 DL |
156 | return (tcp_time_stamp - start_ts) >= timeout; |
157 | } | |
158 | ||
1da177e4 LT |
159 | /* A write timeout has occurred. Process the after effects. */ |
160 | static int tcp_write_timeout(struct sock *sk) | |
161 | { | |
5d424d5a | 162 | struct inet_connection_sock *icsk = inet_csk(sk); |
1da177e4 | 163 | int retry_until; |
3db1cd5c | 164 | bool do_reset, syn_set = false; |
1da177e4 LT |
165 | |
166 | if ((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV)) { | |
463c84b9 | 167 | if (icsk->icsk_retransmits) |
b6c6712a | 168 | dst_negative_advice(sk); |
463c84b9 | 169 | retry_until = icsk->icsk_syn_retries ? : sysctl_tcp_syn_retries; |
3db1cd5c | 170 | syn_set = true; |
1da177e4 | 171 | } else { |
21a180cd | 172 | if (retransmits_timed_out(sk, sysctl_tcp_retries1, 0, 0)) { |
5d424d5a | 173 | /* Black hole detection */ |
ce55dd36 | 174 | tcp_mtu_probing(icsk, sk); |
1da177e4 | 175 | |
b6c6712a | 176 | dst_negative_advice(sk); |
1da177e4 LT |
177 | } |
178 | ||
179 | retry_until = sysctl_tcp_retries2; | |
180 | if (sock_flag(sk, SOCK_DEAD)) { | |
6fa3eb70 | 181 | const int alive = (icsk->icsk_rto < sysctl_tcp_rto_max); |
e905a9ed | 182 | |
1da177e4 | 183 | retry_until = tcp_orphan_retries(sk, alive); |
6fa12c85 | 184 | do_reset = alive || |
21a180cd | 185 | !retransmits_timed_out(sk, retry_until, 0, 0); |
1da177e4 | 186 | |
6fa12c85 | 187 | if (tcp_out_of_resources(sk, do_reset)) |
1da177e4 LT |
188 | return 1; |
189 | } | |
190 | } | |
191 | ||
dca43c75 | 192 | if (retransmits_timed_out(sk, retry_until, |
21a180cd | 193 | syn_set ? 0 : icsk->icsk_user_timeout, syn_set)) { |
1da177e4 LT |
194 | /* Has it gone just too far? */ |
195 | tcp_write_err(sk); | |
196 | return 1; | |
197 | } | |
198 | return 0; | |
199 | } | |
200 | ||
6f458dfb | 201 | void tcp_delack_timer_handler(struct sock *sk) |
1da177e4 | 202 | { |
1da177e4 | 203 | struct tcp_sock *tp = tcp_sk(sk); |
463c84b9 | 204 | struct inet_connection_sock *icsk = inet_csk(sk); |
1da177e4 | 205 | |
9993e7d3 | 206 | sk_mem_reclaim_partial(sk); |
1da177e4 | 207 | |
9b4c2e72 ED |
208 | if (((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)) || |
209 | !(icsk->icsk_ack.pending & ICSK_ACK_TIMER)) | |
1da177e4 LT |
210 | goto out; |
211 | ||
463c84b9 ACM |
212 | if (time_after(icsk->icsk_ack.timeout, jiffies)) { |
213 | sk_reset_timer(sk, &icsk->icsk_delack_timer, icsk->icsk_ack.timeout); | |
1da177e4 LT |
214 | goto out; |
215 | } | |
463c84b9 | 216 | icsk->icsk_ack.pending &= ~ICSK_ACK_TIMER; |
1da177e4 | 217 | |
b03efcfb | 218 | if (!skb_queue_empty(&tp->ucopy.prequeue)) { |
1da177e4 LT |
219 | struct sk_buff *skb; |
220 | ||
de0744af | 221 | NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPSCHEDULERFAILED); |
1da177e4 LT |
222 | |
223 | while ((skb = __skb_dequeue(&tp->ucopy.prequeue)) != NULL) | |
c57943a1 | 224 | sk_backlog_rcv(sk, skb); |
1da177e4 LT |
225 | |
226 | tp->ucopy.memory = 0; | |
227 | } | |
228 | ||
463c84b9 ACM |
229 | if (inet_csk_ack_scheduled(sk)) { |
230 | if (!icsk->icsk_ack.pingpong) { | |
1da177e4 | 231 | /* Delayed ACK missed: inflate ATO. */ |
463c84b9 | 232 | icsk->icsk_ack.ato = min(icsk->icsk_ack.ato << 1, icsk->icsk_rto); |
1da177e4 LT |
233 | } else { |
234 | /* Delayed ACK missed: leave pingpong mode and | |
235 | * deflate ATO. | |
236 | */ | |
463c84b9 ACM |
237 | icsk->icsk_ack.pingpong = 0; |
238 | icsk->icsk_ack.ato = TCP_ATO_MIN; | |
1da177e4 LT |
239 | } |
240 | tcp_send_ack(sk); | |
de0744af | 241 | NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_DELAYEDACKS); |
1da177e4 | 242 | } |
1da177e4 LT |
243 | |
244 | out: | |
180d8cd9 | 245 | if (sk_under_memory_pressure(sk)) |
3ab224be | 246 | sk_mem_reclaim(sk); |
6f458dfb ED |
247 | } |
248 | ||
249 | static void tcp_delack_timer(unsigned long data) | |
250 | { | |
251 | struct sock *sk = (struct sock *)data; | |
252 | ||
253 | bh_lock_sock(sk); | |
254 | if (!sock_owned_by_user(sk)) { | |
255 | tcp_delack_timer_handler(sk); | |
256 | } else { | |
257 | inet_csk(sk)->icsk_ack.blocked = 1; | |
258 | NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_DELAYEDACKLOCKED); | |
259 | /* deleguate our work to tcp_release_cb() */ | |
144d56e9 ED |
260 | if (!test_and_set_bit(TCP_DELACK_TIMER_DEFERRED, &tcp_sk(sk)->tsq_flags)) |
261 | sock_hold(sk); | |
6f458dfb | 262 | } |
1da177e4 LT |
263 | bh_unlock_sock(sk); |
264 | sock_put(sk); | |
265 | } | |
266 | ||
267 | static void tcp_probe_timer(struct sock *sk) | |
268 | { | |
6687e988 | 269 | struct inet_connection_sock *icsk = inet_csk(sk); |
1da177e4 LT |
270 | struct tcp_sock *tp = tcp_sk(sk); |
271 | int max_probes; | |
272 | ||
fe067e8a | 273 | if (tp->packets_out || !tcp_send_head(sk)) { |
6687e988 | 274 | icsk->icsk_probes_out = 0; |
1da177e4 LT |
275 | return; |
276 | } | |
277 | ||
278 | /* *WARNING* RFC 1122 forbids this | |
279 | * | |
280 | * It doesn't AFAIK, because we kill the retransmit timer -AK | |
281 | * | |
282 | * FIXME: We ought not to do it, Solaris 2.5 actually has fixing | |
283 | * this behaviour in Solaris down as a bug fix. [AC] | |
284 | * | |
6687e988 | 285 | * Let me to explain. icsk_probes_out is zeroed by incoming ACKs |
1da177e4 LT |
286 | * even if they advertise zero window. Hence, connection is killed only |
287 | * if we received no ACKs for normal connection timeout. It is not killed | |
288 | * only because window stays zero for some time, window may be zero | |
289 | * until armageddon and even later. We are in full accordance | |
290 | * with RFCs, only probe timer combines both retransmission timeout | |
291 | * and probe timeout in one bottle. --ANK | |
292 | */ | |
293 | max_probes = sysctl_tcp_retries2; | |
294 | ||
295 | if (sock_flag(sk, SOCK_DEAD)) { | |
6fa3eb70 | 296 | const int alive = ((icsk->icsk_rto << icsk->icsk_backoff) < sysctl_tcp_rto_max); |
e905a9ed | 297 | |
1da177e4 LT |
298 | max_probes = tcp_orphan_retries(sk, alive); |
299 | ||
6687e988 | 300 | if (tcp_out_of_resources(sk, alive || icsk->icsk_probes_out <= max_probes)) |
1da177e4 LT |
301 | return; |
302 | } | |
303 | ||
6687e988 | 304 | if (icsk->icsk_probes_out > max_probes) { |
1da177e4 LT |
305 | tcp_write_err(sk); |
306 | } else { | |
307 | /* Only send another probe if we didn't close things up. */ | |
308 | tcp_send_probe0(sk); | |
309 | } | |
310 | } | |
311 | ||
8336886f JC |
312 | /* |
313 | * Timer for Fast Open socket to retransmit SYNACK. Note that the | |
314 | * sk here is the child socket, not the parent (listener) socket. | |
315 | */ | |
316 | static void tcp_fastopen_synack_timer(struct sock *sk) | |
317 | { | |
318 | struct inet_connection_sock *icsk = inet_csk(sk); | |
319 | int max_retries = icsk->icsk_syn_retries ? : | |
320 | sysctl_tcp_synack_retries + 1; /* add one more retry for fastopen */ | |
321 | struct request_sock *req; | |
322 | ||
323 | req = tcp_sk(sk)->fastopen_rsk; | |
324 | req->rsk_ops->syn_ack_timeout(sk, req); | |
325 | ||
e6c022a4 | 326 | if (req->num_timeout >= max_retries) { |
8336886f JC |
327 | tcp_write_err(sk); |
328 | return; | |
329 | } | |
330 | /* XXX (TFO) - Unlike regular SYN-ACK retransmit, we ignore error | |
331 | * returned from rtx_syn_ack() to make it more persistent like | |
332 | * regular retransmit because if the child socket has been accepted | |
333 | * it's not good to give up too easily. | |
334 | */ | |
e6c022a4 ED |
335 | inet_rtx_syn_ack(sk, req); |
336 | req->num_timeout++; | |
8336886f | 337 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, |
6fa3eb70 | 338 | TCP_TIMEOUT_INIT << req->num_timeout, sysctl_tcp_rto_max); |
8336886f JC |
339 | } |
340 | ||
1da177e4 LT |
341 | /* |
342 | * The TCP retransmit timer. | |
343 | */ | |
344 | ||
f1ecd5d9 | 345 | void tcp_retransmit_timer(struct sock *sk) |
1da177e4 LT |
346 | { |
347 | struct tcp_sock *tp = tcp_sk(sk); | |
463c84b9 | 348 | struct inet_connection_sock *icsk = inet_csk(sk); |
1da177e4 | 349 | |
8336886f | 350 | if (tp->fastopen_rsk) { |
37561f68 JC |
351 | WARN_ON_ONCE(sk->sk_state != TCP_SYN_RECV && |
352 | sk->sk_state != TCP_FIN_WAIT1); | |
8336886f JC |
353 | tcp_fastopen_synack_timer(sk); |
354 | /* Before we receive ACK to our SYN-ACK don't retransmit | |
355 | * anything else (e.g., data or FIN segments). | |
356 | */ | |
357 | return; | |
358 | } | |
1da177e4 LT |
359 | if (!tp->packets_out) |
360 | goto out; | |
361 | ||
547b792c | 362 | WARN_ON(tcp_write_queue_empty(sk)); |
1da177e4 | 363 | |
9b717a8d ND |
364 | tp->tlp_high_seq = 0; |
365 | ||
1da177e4 LT |
366 | if (!tp->snd_wnd && !sock_flag(sk, SOCK_DEAD) && |
367 | !((1 << sk->sk_state) & (TCPF_SYN_SENT | TCPF_SYN_RECV))) { | |
368 | /* Receiver dastardly shrinks window. Our retransmits | |
369 | * become zero probes, but we should not timeout this | |
370 | * connection. If the socket is an orphan, time it out, | |
371 | * we cannot allow such beasts to hang infinitely. | |
372 | */ | |
569508c9 YH |
373 | struct inet_sock *inet = inet_sk(sk); |
374 | if (sk->sk_family == AF_INET) { | |
afd46503 JP |
375 | LIMIT_NETDEBUG(KERN_DEBUG pr_fmt("Peer %pI4:%u/%u unexpectedly shrunk window %u:%u (repaired)\n"), |
376 | &inet->inet_daddr, | |
377 | ntohs(inet->inet_dport), inet->inet_num, | |
378 | tp->snd_una, tp->snd_nxt); | |
1da177e4 | 379 | } |
dfd56b8b | 380 | #if IS_ENABLED(CONFIG_IPV6) |
569508c9 YH |
381 | else if (sk->sk_family == AF_INET6) { |
382 | struct ipv6_pinfo *np = inet6_sk(sk); | |
afd46503 JP |
383 | LIMIT_NETDEBUG(KERN_DEBUG pr_fmt("Peer %pI6:%u/%u unexpectedly shrunk window %u:%u (repaired)\n"), |
384 | &np->daddr, | |
385 | ntohs(inet->inet_dport), inet->inet_num, | |
386 | tp->snd_una, tp->snd_nxt); | |
569508c9 | 387 | } |
1da177e4 | 388 | #endif |
6fa3eb70 | 389 | if (tcp_time_stamp - tp->rcv_tstamp > sysctl_tcp_rto_max) { |
1da177e4 LT |
390 | tcp_write_err(sk); |
391 | goto out; | |
392 | } | |
393 | tcp_enter_loss(sk, 0); | |
fe067e8a | 394 | tcp_retransmit_skb(sk, tcp_write_queue_head(sk)); |
1da177e4 LT |
395 | __sk_dst_reset(sk); |
396 | goto out_reset_timer; | |
397 | } | |
398 | ||
399 | if (tcp_write_timeout(sk)) | |
400 | goto out; | |
401 | ||
463c84b9 | 402 | if (icsk->icsk_retransmits == 0) { |
40b215e5 PE |
403 | int mib_idx; |
404 | ||
c60ce4e2 | 405 | if (icsk->icsk_ca_state == TCP_CA_Recovery) { |
bc079e9e IJ |
406 | if (tcp_is_sack(tp)) |
407 | mib_idx = LINUX_MIB_TCPSACKRECOVERYFAIL; | |
408 | else | |
409 | mib_idx = LINUX_MIB_TCPRENORECOVERYFAIL; | |
6687e988 | 410 | } else if (icsk->icsk_ca_state == TCP_CA_Loss) { |
40b215e5 | 411 | mib_idx = LINUX_MIB_TCPLOSSFAILURES; |
c60ce4e2 IJ |
412 | } else if ((icsk->icsk_ca_state == TCP_CA_Disorder) || |
413 | tp->sacked_out) { | |
414 | if (tcp_is_sack(tp)) | |
415 | mib_idx = LINUX_MIB_TCPSACKFAILURES; | |
416 | else | |
417 | mib_idx = LINUX_MIB_TCPRENOFAILURES; | |
1da177e4 | 418 | } else { |
40b215e5 | 419 | mib_idx = LINUX_MIB_TCPTIMEOUTS; |
1da177e4 | 420 | } |
de0744af | 421 | NET_INC_STATS_BH(sock_net(sk), mib_idx); |
1da177e4 LT |
422 | } |
423 | ||
6fa3eb70 S |
424 | if (icsk->icsk_MMSRB == 1) |
425 | { | |
426 | #ifdef CONFIG_MTK_NET_LOGGING | |
427 | printk(KERN_DEBUG "[mtk_net][mmspb] tcp_retransmit_timer enter loss\n"); | |
428 | #endif | |
429 | } | |
9b44190d | 430 | tcp_enter_loss(sk, 0); |
1da177e4 | 431 | |
fe067e8a | 432 | if (tcp_retransmit_skb(sk, tcp_write_queue_head(sk)) > 0) { |
1da177e4 LT |
433 | /* Retransmission failed because of local congestion, |
434 | * do not backoff. | |
435 | */ | |
463c84b9 ACM |
436 | if (!icsk->icsk_retransmits) |
437 | icsk->icsk_retransmits = 1; | |
438 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, | |
3f421baa | 439 | min(icsk->icsk_rto, TCP_RESOURCE_PROBE_INTERVAL), |
6fa3eb70 | 440 | sysctl_tcp_rto_max); |
1da177e4 LT |
441 | goto out; |
442 | } | |
443 | ||
444 | /* Increase the timeout each time we retransmit. Note that | |
445 | * we do not increase the rtt estimate. rto is initialized | |
446 | * from rtt, but increases here. Jacobson (SIGCOMM 88) suggests | |
447 | * that doubling rto each time is the least we can get away with. | |
448 | * In KA9Q, Karn uses this for the first few times, and then | |
449 | * goes to quadratic. netBSD doubles, but only goes up to *64, | |
450 | * and clamps at 1 to 64 sec afterwards. Note that 120 sec is | |
451 | * defined in the protocol as the maximum possible RTT. I guess | |
452 | * we'll have to use something other than TCP to talk to the | |
453 | * University of Mars. | |
454 | * | |
455 | * PAWS allows us longer timeouts and large windows, so once | |
456 | * implemented ftp to mars will work nicely. We will have to fix | |
457 | * the 120 second clamps though! | |
458 | */ | |
463c84b9 ACM |
459 | icsk->icsk_backoff++; |
460 | icsk->icsk_retransmits++; | |
1da177e4 LT |
461 | |
462 | out_reset_timer: | |
36e31b0a AP |
463 | /* If stream is thin, use linear timeouts. Since 'icsk_backoff' is |
464 | * used to reset timer, set to 0. Recalculate 'icsk_rto' as this | |
465 | * might be increased if the stream oscillates between thin and thick, | |
466 | * thus the old value might already be too high compared to the value | |
467 | * set by 'tcp_set_rto' in tcp_input.c which resets the rto without | |
468 | * backoff. Limit to TCP_THIN_LINEAR_RETRIES before initiating | |
469 | * exponential backoff behaviour to avoid continue hammering | |
470 | * linear-timeout retransmissions into a black hole | |
471 | */ | |
472 | if (sk->sk_state == TCP_ESTABLISHED && | |
473 | (tp->thin_lto || sysctl_tcp_thin_linear_timeouts) && | |
474 | tcp_stream_is_thin(tp) && | |
475 | icsk->icsk_retransmits <= TCP_THIN_LINEAR_RETRIES) { | |
476 | icsk->icsk_backoff = 0; | |
6fa3eb70 | 477 | icsk->icsk_rto = min_t(unsigned int, __tcp_set_rto(tp), sysctl_tcp_rto_max); |
36e31b0a AP |
478 | } else { |
479 | /* Use normal (exponential) backoff */ | |
6fa3eb70 | 480 | icsk->icsk_rto = min_t(unsigned int, icsk->icsk_rto << 1, sysctl_tcp_rto_max); |
36e31b0a | 481 | } |
6fa3eb70 | 482 | inet_csk_reset_xmit_timer(sk, ICSK_TIME_RETRANS, icsk->icsk_rto, sysctl_tcp_rto_max); |
21a180cd | 483 | if (retransmits_timed_out(sk, sysctl_tcp_retries1 + 1, 0, 0)) |
1da177e4 LT |
484 | __sk_dst_reset(sk); |
485 | ||
486 | out:; | |
487 | } | |
488 | ||
6f458dfb | 489 | void tcp_write_timer_handler(struct sock *sk) |
1da177e4 | 490 | { |
463c84b9 | 491 | struct inet_connection_sock *icsk = inet_csk(sk); |
1da177e4 LT |
492 | int event; |
493 | ||
9b4c2e72 ED |
494 | if (((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)) || |
495 | !icsk->icsk_pending) | |
1da177e4 | 496 | goto out; |
6fa3eb70 S |
497 | if (icsk->icsk_MMSRB != 1) |
498 | { | |
463c84b9 ACM |
499 | if (time_after(icsk->icsk_timeout, jiffies)) { |
500 | sk_reset_timer(sk, &icsk->icsk_retransmit_timer, icsk->icsk_timeout); | |
1da177e4 LT |
501 | goto out; |
502 | } | |
6fa3eb70 | 503 | } |
463c84b9 | 504 | event = icsk->icsk_pending; |
1da177e4 LT |
505 | |
506 | switch (event) { | |
6ba8a3b1 ND |
507 | case ICSK_TIME_EARLY_RETRANS: |
508 | tcp_resume_early_retransmit(sk); | |
509 | break; | |
510 | case ICSK_TIME_LOSS_PROBE: | |
511 | tcp_send_loss_probe(sk); | |
512 | break; | |
463c84b9 | 513 | case ICSK_TIME_RETRANS: |
6ba8a3b1 | 514 | icsk->icsk_pending = 0; |
1da177e4 LT |
515 | tcp_retransmit_timer(sk); |
516 | break; | |
463c84b9 | 517 | case ICSK_TIME_PROBE0: |
6ba8a3b1 | 518 | icsk->icsk_pending = 0; |
1da177e4 LT |
519 | tcp_probe_timer(sk); |
520 | break; | |
521 | } | |
1da177e4 LT |
522 | |
523 | out: | |
3ab224be | 524 | sk_mem_reclaim(sk); |
6f458dfb ED |
525 | } |
526 | ||
527 | static void tcp_write_timer(unsigned long data) | |
528 | { | |
529 | struct sock *sk = (struct sock *)data; | |
530 | ||
531 | bh_lock_sock(sk); | |
532 | if (!sock_owned_by_user(sk)) { | |
533 | tcp_write_timer_handler(sk); | |
534 | } else { | |
6fa3eb70 S |
535 | |
536 | //if (icsk->icsk_MMSRB == 1) | |
537 | //printk("[mmspb] tcp_write_timer user owner sock\n"); | |
538 | ||
6f458dfb | 539 | /* deleguate our work to tcp_release_cb() */ |
144d56e9 ED |
540 | if (!test_and_set_bit(TCP_WRITE_TIMER_DEFERRED, &tcp_sk(sk)->tsq_flags)) |
541 | sock_hold(sk); | |
6f458dfb | 542 | } |
1da177e4 LT |
543 | bh_unlock_sock(sk); |
544 | sock_put(sk); | |
545 | } | |
546 | ||
295f7324 ACM |
547 | /* |
548 | * Timer for listening sockets | |
549 | */ | |
550 | ||
551 | static void tcp_synack_timer(struct sock *sk) | |
552 | { | |
a019d6fe | 553 | inet_csk_reqsk_queue_prune(sk, TCP_SYNQ_INTERVAL, |
6fa3eb70 | 554 | TCP_TIMEOUT_INIT, sysctl_tcp_rto_max); |
1da177e4 LT |
555 | } |
556 | ||
72659ecc OP |
557 | void tcp_syn_ack_timeout(struct sock *sk, struct request_sock *req) |
558 | { | |
559 | NET_INC_STATS_BH(sock_net(sk), LINUX_MIB_TCPTIMEOUTS); | |
560 | } | |
561 | EXPORT_SYMBOL(tcp_syn_ack_timeout); | |
562 | ||
1da177e4 LT |
563 | void tcp_set_keepalive(struct sock *sk, int val) |
564 | { | |
565 | if ((1 << sk->sk_state) & (TCPF_CLOSE | TCPF_LISTEN)) | |
566 | return; | |
567 | ||
568 | if (val && !sock_flag(sk, SOCK_KEEPOPEN)) | |
463c84b9 | 569 | inet_csk_reset_keepalive_timer(sk, keepalive_time_when(tcp_sk(sk))); |
1da177e4 | 570 | else if (!val) |
463c84b9 | 571 | inet_csk_delete_keepalive_timer(sk); |
1da177e4 LT |
572 | } |
573 | ||
574 | ||
575 | static void tcp_keepalive_timer (unsigned long data) | |
576 | { | |
577 | struct sock *sk = (struct sock *) data; | |
6687e988 | 578 | struct inet_connection_sock *icsk = inet_csk(sk); |
1da177e4 | 579 | struct tcp_sock *tp = tcp_sk(sk); |
6c37e5de | 580 | u32 elapsed; |
1da177e4 LT |
581 | |
582 | /* Only process if socket is not in use. */ | |
583 | bh_lock_sock(sk); | |
584 | if (sock_owned_by_user(sk)) { | |
e905a9ed | 585 | /* Try again later. */ |
463c84b9 | 586 | inet_csk_reset_keepalive_timer (sk, HZ/20); |
1da177e4 LT |
587 | goto out; |
588 | } | |
589 | ||
590 | if (sk->sk_state == TCP_LISTEN) { | |
591 | tcp_synack_timer(sk); | |
592 | goto out; | |
593 | } | |
594 | ||
595 | if (sk->sk_state == TCP_FIN_WAIT2 && sock_flag(sk, SOCK_DEAD)) { | |
596 | if (tp->linger2 >= 0) { | |
463c84b9 | 597 | const int tmo = tcp_fin_time(sk) - TCP_TIMEWAIT_LEN; |
1da177e4 LT |
598 | |
599 | if (tmo > 0) { | |
600 | tcp_time_wait(sk, TCP_FIN_WAIT2, tmo); | |
601 | goto out; | |
602 | } | |
603 | } | |
604 | tcp_send_active_reset(sk, GFP_ATOMIC); | |
605 | goto death; | |
606 | } | |
607 | ||
608 | if (!sock_flag(sk, SOCK_KEEPOPEN) || sk->sk_state == TCP_CLOSE) | |
609 | goto out; | |
610 | ||
611 | elapsed = keepalive_time_when(tp); | |
612 | ||
613 | /* It is alive without keepalive 8) */ | |
fe067e8a | 614 | if (tp->packets_out || tcp_send_head(sk)) |
1da177e4 LT |
615 | goto resched; |
616 | ||
6c37e5de | 617 | elapsed = keepalive_time_elapsed(tp); |
1da177e4 LT |
618 | |
619 | if (elapsed >= keepalive_time_when(tp)) { | |
dca43c75 JC |
620 | /* If the TCP_USER_TIMEOUT option is enabled, use that |
621 | * to determine when to timeout instead. | |
622 | */ | |
623 | if ((icsk->icsk_user_timeout != 0 && | |
624 | elapsed >= icsk->icsk_user_timeout && | |
625 | icsk->icsk_probes_out > 0) || | |
626 | (icsk->icsk_user_timeout == 0 && | |
627 | icsk->icsk_probes_out >= keepalive_probes(tp))) { | |
1da177e4 LT |
628 | tcp_send_active_reset(sk, GFP_ATOMIC); |
629 | tcp_write_err(sk); | |
630 | goto out; | |
631 | } | |
632 | if (tcp_write_wakeup(sk) <= 0) { | |
6687e988 | 633 | icsk->icsk_probes_out++; |
1da177e4 LT |
634 | elapsed = keepalive_intvl_when(tp); |
635 | } else { | |
636 | /* If keepalive was lost due to local congestion, | |
637 | * try harder. | |
638 | */ | |
639 | elapsed = TCP_RESOURCE_PROBE_INTERVAL; | |
640 | } | |
641 | } else { | |
642 | /* It is tp->rcv_tstamp + keepalive_time_when(tp) */ | |
643 | elapsed = keepalive_time_when(tp) - elapsed; | |
644 | } | |
645 | ||
3ab224be | 646 | sk_mem_reclaim(sk); |
1da177e4 LT |
647 | |
648 | resched: | |
463c84b9 | 649 | inet_csk_reset_keepalive_timer (sk, elapsed); |
1da177e4 LT |
650 | goto out; |
651 | ||
e905a9ed | 652 | death: |
1da177e4 LT |
653 | tcp_done(sk); |
654 | ||
655 | out: | |
656 | bh_unlock_sock(sk); | |
657 | sock_put(sk); | |
658 | } | |
6f458dfb ED |
659 | |
660 | void tcp_init_xmit_timers(struct sock *sk) | |
661 | { | |
662 | inet_csk_init_xmit_timers(sk, &tcp_write_timer, &tcp_delack_timer, | |
663 | &tcp_keepalive_timer); | |
664 | } | |
665 | EXPORT_SYMBOL(tcp_init_xmit_timers); |