File: | netinet/tcp_timer.c |
Warning: | line 429, column 3 Value stored to 'tp' is never read |
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1 | /* $OpenBSD: tcp_timer.c,v 1.73 2023/07/06 09:15:24 bluhm Exp $ */ |
2 | /* $NetBSD: tcp_timer.c,v 1.14 1996/02/13 23:44:09 christos Exp $ */ |
3 | |
4 | /* |
5 | * Copyright (c) 1982, 1986, 1988, 1990, 1993 |
6 | * The Regents of the University of California. All rights reserved. |
7 | * |
8 | * Redistribution and use in source and binary forms, with or without |
9 | * modification, are permitted provided that the following conditions |
10 | * are met: |
11 | * 1. Redistributions of source code must retain the above copyright |
12 | * notice, this list of conditions and the following disclaimer. |
13 | * 2. Redistributions in binary form must reproduce the above copyright |
14 | * notice, this list of conditions and the following disclaimer in the |
15 | * documentation and/or other materials provided with the distribution. |
16 | * 3. Neither the name of the University nor the names of its contributors |
17 | * may be used to endorse or promote products derived from this software |
18 | * without specific prior written permission. |
19 | * |
20 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
21 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
22 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
23 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
24 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
25 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
26 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
27 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
28 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
29 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
30 | * SUCH DAMAGE. |
31 | * |
32 | * @(#)tcp_timer.c 8.1 (Berkeley) 6/10/93 |
33 | */ |
34 | |
35 | #include <sys/param.h> |
36 | #include <sys/systm.h> |
37 | #include <sys/mbuf.h> |
38 | #include <sys/socket.h> |
39 | #include <sys/socketvar.h> |
40 | #include <sys/protosw.h> |
41 | #include <sys/kernel.h> |
42 | #include <sys/pool.h> |
43 | |
44 | #include <net/route.h> |
45 | |
46 | #include <netinet/in.h> |
47 | #include <netinet/ip.h> |
48 | #include <netinet/in_pcb.h> |
49 | #include <netinet/ip_var.h> |
50 | #include <netinet/tcp.h> |
51 | #include <netinet/tcp_fsm.h> |
52 | #include <netinet/tcp_timer.h> |
53 | #include <netinet/tcp_var.h> |
54 | #include <netinet/tcp_debug.h> |
55 | #include <netinet/ip_icmp.h> |
56 | #include <netinet/tcp_seq.h> |
57 | |
58 | /* |
59 | * Locks used to protect struct members in this file: |
60 | * T tcp_timer_mtx global tcp timer data structures |
61 | */ |
62 | |
63 | int tcp_always_keepalive; |
64 | int tcp_keepidle; |
65 | int tcp_keepintvl; |
66 | int tcp_maxpersistidle; /* max idle time in persist */ |
67 | int tcp_maxidle; /* [T] max idle time for keep alive */ |
68 | |
69 | /* |
70 | * Time to delay the ACK. This is initialized in tcp_init(), unless |
71 | * its patched. |
72 | */ |
73 | int tcp_delack_msecs; |
74 | |
75 | void tcp_timer_rexmt(void *); |
76 | void tcp_timer_persist(void *); |
77 | void tcp_timer_keep(void *); |
78 | void tcp_timer_2msl(void *); |
79 | void tcp_timer_reaper(void *); |
80 | void tcp_timer_delack(void *); |
81 | |
82 | const tcp_timer_func_t tcp_timer_funcs[TCPT_NTIMERS6] = { |
83 | tcp_timer_rexmt, |
84 | tcp_timer_persist, |
85 | tcp_timer_keep, |
86 | tcp_timer_2msl, |
87 | tcp_timer_reaper, |
88 | tcp_timer_delack, |
89 | }; |
90 | |
91 | /* |
92 | * Timer state initialization, called from tcp_init(). |
93 | */ |
94 | void |
95 | tcp_timer_init(void) |
96 | { |
97 | |
98 | if (tcp_keepidle == 0) |
99 | tcp_keepidle = TCPTV_KEEP_IDLE((120*60) * 1000); |
100 | |
101 | if (tcp_keepintvl == 0) |
102 | tcp_keepintvl = TCPTV_KEEPINTVL((75) * 1000); |
103 | |
104 | if (tcp_maxpersistidle == 0) |
105 | tcp_maxpersistidle = TCPTV_KEEP_IDLE((120*60) * 1000); |
106 | |
107 | if (tcp_delack_msecs == 0) |
108 | tcp_delack_msecs = TCP_DELACK_MSECS200; |
109 | } |
110 | |
111 | /* |
112 | * Callout to process delayed ACKs for a TCPCB. |
113 | */ |
114 | void |
115 | tcp_timer_delack(void *arg) |
116 | { |
117 | struct tcpcb *otp = NULL((void *)0), *tp = arg; |
118 | short ostate; |
119 | |
120 | /* |
121 | * If tcp_output() wasn't able to transmit the ACK |
122 | * for whatever reason, it will restart the delayed |
123 | * ACK callout. |
124 | */ |
125 | NET_LOCK()do { rw_enter_write(&netlock); } while (0); |
126 | /* Ignore canceled timeouts or timeouts that have been rescheduled. */ |
127 | if (!ISSET((tp)->t_flags, TF_TMR_DELACK)(((tp)->t_flags) & (0x80000000U)) || |
128 | timeout_pending(&tp->t_timer[TCPT_DELACK])((&tp->t_timer[5])->to_flags & 0x02)) |
129 | goto out; |
130 | CLR((tp)->t_flags, TF_TMR_DELACK)(((tp)->t_flags) &= ~(0x80000000U)); |
131 | |
132 | if (tp->t_inpcb->inp_socket->so_options & SO_DEBUG0x0001) { |
133 | otp = tp; |
134 | ostate = tp->t_state; |
135 | } |
136 | tp->t_flags |= TF_ACKNOW0x0001U; |
137 | (void) tcp_output(tp); |
138 | if (otp) |
139 | tcp_trace(TA_TIMER5, ostate, tp, otp, NULL((void *)0), TCPT_DELACK5, 0); |
140 | out: |
141 | NET_UNLOCK()do { rw_exit_write(&netlock); } while (0); |
142 | } |
143 | |
144 | /* |
145 | * Tcp protocol timeout routine called every 500 ms. |
146 | * Updates the timers in all active tcb's and |
147 | * causes finite state machine actions if timers expire. |
148 | */ |
149 | void |
150 | tcp_slowtimo(void) |
151 | { |
152 | mtx_enter(&tcp_timer_mtx); |
153 | tcp_maxidle = TCPTV_KEEPCNT8 * tcp_keepintvl; |
154 | tcp_iss += TCP_ISSINCR2(1*1024*1024)/PR_SLOWHZ2; /* increment iss */ |
155 | mtx_leave(&tcp_timer_mtx); |
156 | } |
157 | |
158 | /* |
159 | * Cancel all timers for TCP tp. |
160 | */ |
161 | void |
162 | tcp_canceltimers(struct tcpcb *tp) |
163 | { |
164 | int i; |
165 | |
166 | for (i = 0; i < TCPT_NTIMERS6; i++) |
167 | TCP_TIMER_DISARM(tp, i)do { (((tp)->t_flags) &= ~(0x04000000U << (i))); timeout_del(&(tp)->t_timer[(i)]); } while (0); |
168 | } |
169 | |
170 | int tcp_backoff[TCP_MAXRXTSHIFT12 + 1] = |
171 | { 1, 2, 4, 8, 16, 32, 64, 64, 64, 64, 64, 64, 64 }; |
172 | |
173 | int tcp_totbackoff = 511; /* sum of tcp_backoff[] */ |
174 | |
175 | /* |
176 | * TCP timer processing. |
177 | */ |
178 | |
179 | void tcp_timer_freesack(struct tcpcb *); |
180 | |
181 | void |
182 | tcp_timer_freesack(struct tcpcb *tp) |
183 | { |
184 | struct sackhole *p, *q; |
185 | /* |
186 | * Free SACK holes for 2MSL and REXMT timers. |
187 | */ |
188 | q = tp->snd_holes; |
189 | while (q != NULL((void *)0)) { |
190 | p = q; |
191 | q = q->next; |
192 | pool_put(&sackhl_pool, p); |
193 | } |
194 | tp->snd_holes = 0; |
195 | } |
196 | |
197 | void |
198 | tcp_timer_rexmt(void *arg) |
199 | { |
200 | struct tcpcb *otp = NULL((void *)0), *tp = arg; |
201 | uint32_t rto; |
202 | short ostate; |
203 | |
204 | NET_LOCK()do { rw_enter_write(&netlock); } while (0); |
205 | /* Ignore canceled timeouts or timeouts that have been rescheduled. */ |
206 | if (!ISSET((tp)->t_flags, TF_TMR_REXMT)(((tp)->t_flags) & (0x04000000U)) || |
207 | timeout_pending(&tp->t_timer[TCPT_REXMT])((&tp->t_timer[0])->to_flags & 0x02)) |
208 | goto out; |
209 | CLR((tp)->t_flags, TF_TMR_REXMT)(((tp)->t_flags) &= ~(0x04000000U)); |
210 | |
211 | if ((tp->t_flags & TF_PMTUD_PEND0x00400000U) && tp->t_inpcb && |
212 | SEQ_GEQ(tp->t_pmtud_th_seq, tp->snd_una)((int)((tp->t_pmtud_th_seq)-(tp->snd_una)) >= 0) && |
213 | SEQ_LT(tp->t_pmtud_th_seq, (int)(tp->snd_una + tp->t_maxseg))((int)((tp->t_pmtud_th_seq)-((int)(tp->snd_una + tp-> t_maxseg))) < 0)) { |
214 | struct sockaddr_in sin; |
215 | struct icmp icmp; |
216 | |
217 | tp->t_flags &= ~TF_PMTUD_PEND0x00400000U; |
218 | |
219 | /* XXX create fake icmp message with relevant entries */ |
220 | icmp.icmp_nextmtuicmp_hun.ih_pmtu.ipm_nextmtu = tp->t_pmtud_nextmtu; |
221 | icmp.icmp_ipicmp_dun.id_ip.idi_ip.ip_len = tp->t_pmtud_ip_len; |
222 | icmp.icmp_ipicmp_dun.id_ip.idi_ip.ip_hl = tp->t_pmtud_ip_hl; |
223 | icmp.icmp_ipicmp_dun.id_ip.idi_ip.ip_dst = tp->t_inpcb->inp_faddrinp_faddru.iau_a4u.inaddr; |
224 | icmp_mtudisc(&icmp, tp->t_inpcb->inp_rtableid); |
225 | |
226 | /* |
227 | * Notify all connections to the same peer about |
228 | * new mss and trigger retransmit. |
229 | */ |
230 | bzero(&sin, sizeof(sin))__builtin_bzero((&sin), (sizeof(sin))); |
231 | sin.sin_len = sizeof(sin); |
232 | sin.sin_family = AF_INET2; |
233 | sin.sin_addr = tp->t_inpcb->inp_faddrinp_faddru.iau_a4u.inaddr; |
234 | in_pcbnotifyall(&tcbtable, sintosa(&sin), |
235 | tp->t_inpcb->inp_rtableid, EMSGSIZE40, tcp_mtudisc); |
236 | goto out; |
237 | } |
238 | |
239 | tcp_timer_freesack(tp); |
240 | if (++tp->t_rxtshift > TCP_MAXRXTSHIFT12) { |
241 | tp->t_rxtshift = TCP_MAXRXTSHIFT12; |
242 | tcpstat_inc(tcps_timeoutdrop); |
243 | tp = tcp_drop(tp, tp->t_softerror ? |
244 | tp->t_softerror : ETIMEDOUT60); |
245 | goto out; |
246 | } |
247 | if (tp->t_inpcb->inp_socket->so_options & SO_DEBUG0x0001) { |
248 | otp = tp; |
249 | ostate = tp->t_state; |
250 | } |
251 | tcpstat_inc(tcps_rexmttimeo); |
252 | rto = TCP_REXMTVAL(tp)((((tp)->t_srtt >> 3) + (tp)->t_rttvar) >> 2 ); |
253 | if (rto < tp->t_rttmin) |
254 | rto = tp->t_rttmin; |
255 | TCPT_RANGESET(tp->t_rxtcur,do { (tp->t_rxtcur) = (rto * tcp_backoff[tp->t_rxtshift ]); if ((tp->t_rxtcur) < (tp->t_rttmin)) (tp->t_rxtcur ) = (tp->t_rttmin); else if ((tp->t_rxtcur) > (((64) * 1000))) (tp->t_rxtcur) = (((64) * 1000)); } while ( 0) |
256 | rto * tcp_backoff[tp->t_rxtshift],do { (tp->t_rxtcur) = (rto * tcp_backoff[tp->t_rxtshift ]); if ((tp->t_rxtcur) < (tp->t_rttmin)) (tp->t_rxtcur ) = (tp->t_rttmin); else if ((tp->t_rxtcur) > (((64) * 1000))) (tp->t_rxtcur) = (((64) * 1000)); } while ( 0) |
257 | tp->t_rttmin, TCPTV_REXMTMAX)do { (tp->t_rxtcur) = (rto * tcp_backoff[tp->t_rxtshift ]); if ((tp->t_rxtcur) < (tp->t_rttmin)) (tp->t_rxtcur ) = (tp->t_rttmin); else if ((tp->t_rxtcur) > (((64) * 1000))) (tp->t_rxtcur) = (((64) * 1000)); } while ( 0); |
258 | TCP_TIMER_ARM(tp, TCPT_REXMT, tp->t_rxtcur)do { (((tp)->t_flags) |= (0x04000000U << (0))); timeout_add_msec (&(tp)->t_timer[(0)], (tp->t_rxtcur)); } while (0); |
259 | |
260 | /* |
261 | * If we are losing and we are trying path MTU discovery, |
262 | * try turning it off. This will avoid black holes in |
263 | * the network which suppress or fail to send "packet |
264 | * too big" ICMP messages. We should ideally do |
265 | * lots more sophisticated searching to find the right |
266 | * value here... |
267 | */ |
268 | if (ip_mtudisc && tp->t_inpcb && |
269 | TCPS_HAVEESTABLISHED(tp->t_state)((tp->t_state) >= 4) && |
270 | tp->t_rxtshift > TCP_MAXRXTSHIFT12 / 6) { |
271 | struct inpcb *inp = tp->t_inpcb; |
272 | struct rtentry *rt = NULL((void *)0); |
273 | |
274 | /* No data to send means path mtu is not a problem */ |
275 | if (!inp->inp_socket->so_snd.sb_cc) |
276 | goto leave; |
277 | |
278 | rt = in_pcbrtentry(inp); |
279 | /* Check if path MTU discovery is disabled already */ |
280 | if (rt && (rt->rt_flags & RTF_HOST0x4) && |
281 | (rt->rt_locksrt_rmx.rmx_locks & RTV_MTU0x1)) |
282 | goto leave; |
283 | |
284 | rt = NULL((void *)0); |
285 | switch(tp->pf) { |
286 | #ifdef INET61 |
287 | case PF_INET624: |
288 | /* |
289 | * We can not turn off path MTU for IPv6. |
290 | * Do nothing for now, maybe lower to |
291 | * minimum MTU. |
292 | */ |
293 | break; |
294 | #endif |
295 | case PF_INET2: |
296 | rt = icmp_mtudisc_clone(inp->inp_faddrinp_faddru.iau_a4u.inaddr, |
297 | inp->inp_rtableid, 0); |
298 | break; |
299 | } |
300 | if (rt != NULL((void *)0)) { |
301 | /* Disable path MTU discovery */ |
302 | if ((rt->rt_locksrt_rmx.rmx_locks & RTV_MTU0x1) == 0) { |
303 | rt->rt_locksrt_rmx.rmx_locks |= RTV_MTU0x1; |
304 | in_rtchange(inp, 0); |
305 | } |
306 | |
307 | rtfree(rt); |
308 | } |
309 | leave: |
310 | ; |
311 | } |
312 | |
313 | /* |
314 | * If losing, let the lower level know and try for |
315 | * a better route. Also, if we backed off this far, |
316 | * our srtt estimate is probably bogus. Clobber it |
317 | * so we'll take the next rtt measurement as our srtt; |
318 | * move the current srtt into rttvar to keep the current |
319 | * retransmit times until then. |
320 | */ |
321 | if (tp->t_rxtshift > TCP_MAXRXTSHIFT12 / 4) { |
322 | in_losing(tp->t_inpcb); |
323 | tp->t_rttvar += (tp->t_srtt >> TCP_RTT_SHIFT3); |
324 | tp->t_srtt = 0; |
325 | } |
326 | tp->snd_nxt = tp->snd_una; |
327 | /* |
328 | * Note: We overload snd_last to function also as the |
329 | * snd_last variable described in RFC 2582 |
330 | */ |
331 | tp->snd_last = tp->snd_max; |
332 | /* |
333 | * If timing a segment in this window, stop the timer. |
334 | */ |
335 | tp->t_rtttime = 0; |
336 | #ifdef TCP_ECN1 |
337 | /* |
338 | * if ECN is enabled, there might be a broken firewall which |
339 | * blocks ecn packets. fall back to non-ecn. |
340 | */ |
341 | if ((tp->t_state == TCPS_SYN_SENT2 || tp->t_state == TCPS_SYN_RECEIVED3) |
342 | && tcp_do_ecn && !(tp->t_flags & TF_DISABLE_ECN0x00040000U)) |
343 | tp->t_flags |= TF_DISABLE_ECN0x00040000U; |
344 | #endif |
345 | /* |
346 | * Close the congestion window down to one segment |
347 | * (we'll open it by one segment for each ack we get). |
348 | * Since we probably have a window's worth of unacked |
349 | * data accumulated, this "slow start" keeps us from |
350 | * dumping all that data as back-to-back packets (which |
351 | * might overwhelm an intermediate gateway). |
352 | * |
353 | * There are two phases to the opening: Initially we |
354 | * open by one mss on each ack. This makes the window |
355 | * size increase exponentially with time. If the |
356 | * window is larger than the path can handle, this |
357 | * exponential growth results in dropped packet(s) |
358 | * almost immediately. To get more time between |
359 | * drops but still "push" the network to take advantage |
360 | * of improving conditions, we switch from exponential |
361 | * to linear window opening at some threshold size. |
362 | * For a threshold, we use half the current window |
363 | * size, truncated to a multiple of the mss. |
364 | * |
365 | * (the minimum cwnd that will give us exponential |
366 | * growth is 2 mss. We don't allow the threshold |
367 | * to go below this.) |
368 | */ |
369 | { |
370 | u_long win = ulmin(tp->snd_wnd, tp->snd_cwnd) / 2 / tp->t_maxseg; |
371 | if (win < 2) |
372 | win = 2; |
373 | tp->snd_cwnd = tp->t_maxseg; |
374 | tp->snd_ssthresh = win * tp->t_maxseg; |
375 | tp->t_dupacks = 0; |
376 | #ifdef TCP_ECN1 |
377 | tp->snd_last = tp->snd_max; |
378 | tp->t_flags |= TF_SEND_CWR0x00020000U; |
379 | #endif |
380 | #if 1 /* TCP_ECN */ |
381 | tcpstat_inc(tcps_cwr_timeout); |
382 | #endif |
383 | } |
384 | (void) tcp_output(tp); |
385 | if (otp) |
386 | tcp_trace(TA_TIMER5, ostate, tp, otp, NULL((void *)0), TCPT_REXMT0, 0); |
387 | out: |
388 | NET_UNLOCK()do { rw_exit_write(&netlock); } while (0); |
389 | } |
390 | |
391 | void |
392 | tcp_timer_persist(void *arg) |
393 | { |
394 | struct tcpcb *otp = NULL((void *)0), *tp = arg; |
395 | uint32_t rto; |
396 | short ostate; |
397 | uint64_t now; |
398 | |
399 | NET_LOCK()do { rw_enter_write(&netlock); } while (0); |
400 | /* Ignore canceled timeouts or timeouts that have been rescheduled. */ |
401 | if (!ISSET((tp)->t_flags, TF_TMR_PERSIST)(((tp)->t_flags) & (0x08000000U)) || |
402 | timeout_pending(&tp->t_timer[TCPT_PERSIST])((&tp->t_timer[1])->to_flags & 0x02)) |
403 | goto out; |
404 | CLR((tp)->t_flags, TF_TMR_PERSIST)(((tp)->t_flags) &= ~(0x08000000U)); |
405 | |
406 | if (TCP_TIMER_ISARMED(tp, TCPT_REXMT)(((tp)->t_flags) & (0x04000000U << (0)))) |
407 | goto out; |
408 | |
409 | if (tp->t_inpcb->inp_socket->so_options & SO_DEBUG0x0001) { |
410 | otp = tp; |
411 | ostate = tp->t_state; |
412 | } |
413 | tcpstat_inc(tcps_persisttimeo); |
414 | /* |
415 | * Hack: if the peer is dead/unreachable, we do not |
416 | * time out if the window is closed. After a full |
417 | * backoff, drop the connection if the idle time |
418 | * (no responses to probes) reaches the maximum |
419 | * backoff that we would use if retransmitting. |
420 | */ |
421 | rto = TCP_REXMTVAL(tp)((((tp)->t_srtt >> 3) + (tp)->t_rttvar) >> 2 ); |
422 | if (rto < tp->t_rttmin) |
423 | rto = tp->t_rttmin; |
424 | now = tcp_now(); |
425 | if (tp->t_rxtshift == TCP_MAXRXTSHIFT12 && |
426 | ((now - tp->t_rcvtime) >= tcp_maxpersistidle || |
427 | (now - tp->t_rcvtime) >= rto * tcp_totbackoff)) { |
428 | tcpstat_inc(tcps_persistdrop); |
429 | tp = tcp_drop(tp, ETIMEDOUT60); |
Value stored to 'tp' is never read | |
430 | goto out; |
431 | } |
432 | tcp_setpersist(tp); |
433 | tp->t_force = 1; |
434 | (void) tcp_output(tp); |
435 | tp->t_force = 0; |
436 | if (otp) |
437 | tcp_trace(TA_TIMER5, ostate, tp, otp, NULL((void *)0), TCPT_PERSIST1, 0); |
438 | out: |
439 | NET_UNLOCK()do { rw_exit_write(&netlock); } while (0); |
440 | } |
441 | |
442 | void |
443 | tcp_timer_keep(void *arg) |
444 | { |
445 | struct tcpcb *otp = NULL((void *)0), *tp = arg; |
446 | short ostate; |
447 | |
448 | NET_LOCK()do { rw_enter_write(&netlock); } while (0); |
449 | /* Ignore canceled timeouts or timeouts that have been rescheduled. */ |
450 | if (!ISSET((tp)->t_flags, TF_TMR_KEEP)(((tp)->t_flags) & (0x10000000U)) || |
451 | timeout_pending(&tp->t_timer[TCPT_KEEP])((&tp->t_timer[2])->to_flags & 0x02)) |
452 | goto out; |
453 | CLR((tp)->t_flags, TF_TMR_KEEP)(((tp)->t_flags) &= ~(0x10000000U)); |
454 | |
455 | if (tp->t_inpcb->inp_socket->so_options & SO_DEBUG0x0001) { |
456 | otp = tp; |
457 | ostate = tp->t_state; |
458 | } |
459 | tcpstat_inc(tcps_keeptimeo); |
460 | if (TCPS_HAVEESTABLISHED(tp->t_state)((tp->t_state) >= 4) == 0) |
461 | goto dropit; |
462 | if ((tcp_always_keepalive || |
463 | tp->t_inpcb->inp_socket->so_options & SO_KEEPALIVE0x0008) && |
464 | tp->t_state <= TCPS_CLOSING7) { |
465 | int maxidle; |
466 | uint64_t now; |
467 | |
468 | maxidle = READ_ONCE(tcp_maxidle)({ typeof(tcp_maxidle) __tmp = *(volatile typeof(tcp_maxidle) *)&(tcp_maxidle); membar_datadep_consumer(); __tmp; }); |
469 | now = tcp_now(); |
470 | if ((maxidle > 0) && |
471 | ((now - tp->t_rcvtime) >= tcp_keepidle + maxidle)) |
472 | goto dropit; |
473 | /* |
474 | * Send a packet designed to force a response |
475 | * if the peer is up and reachable: |
476 | * either an ACK if the connection is still alive, |
477 | * or an RST if the peer has closed the connection |
478 | * due to timeout or reboot. |
479 | * Using sequence number tp->snd_una-1 |
480 | * causes the transmitted zero-length segment |
481 | * to lie outside the receive window; |
482 | * by the protocol spec, this requires the |
483 | * correspondent TCP to respond. |
484 | */ |
485 | tcpstat_inc(tcps_keepprobe); |
486 | tcp_respond(tp, mtod(tp->t_template, caddr_t)((caddr_t)((tp->t_template)->m_hdr.mh_data)), |
487 | NULL((void *)0), tp->rcv_nxt, tp->snd_una - 1, 0, 0, now); |
488 | TCP_TIMER_ARM(tp, TCPT_KEEP, tcp_keepintvl)do { (((tp)->t_flags) |= (0x04000000U << (2))); timeout_add_msec (&(tp)->t_timer[(2)], (tcp_keepintvl)); } while (0); |
489 | } else |
490 | TCP_TIMER_ARM(tp, TCPT_KEEP, tcp_keepidle)do { (((tp)->t_flags) |= (0x04000000U << (2))); timeout_add_msec (&(tp)->t_timer[(2)], (tcp_keepidle)); } while (0); |
491 | if (otp) |
492 | tcp_trace(TA_TIMER5, ostate, tp, otp, NULL((void *)0), TCPT_KEEP2, 0); |
493 | out: |
494 | NET_UNLOCK()do { rw_exit_write(&netlock); } while (0); |
495 | return; |
496 | |
497 | dropit: |
498 | tcpstat_inc(tcps_keepdrops); |
499 | tp = tcp_drop(tp, ETIMEDOUT60); |
500 | NET_UNLOCK()do { rw_exit_write(&netlock); } while (0); |
501 | } |
502 | |
503 | void |
504 | tcp_timer_2msl(void *arg) |
505 | { |
506 | struct tcpcb *otp = NULL((void *)0), *tp = arg; |
507 | short ostate; |
508 | int maxidle; |
509 | uint64_t now; |
510 | |
511 | NET_LOCK()do { rw_enter_write(&netlock); } while (0); |
512 | /* Ignore canceled timeouts or timeouts that have been rescheduled. */ |
513 | if (!ISSET((tp)->t_flags, TF_TMR_2MSL)(((tp)->t_flags) & (0x20000000U)) || |
514 | timeout_pending(&tp->t_timer[TCPT_2MSL])((&tp->t_timer[3])->to_flags & 0x02)) |
515 | goto out; |
516 | CLR((tp)->t_flags, TF_TMR_2MSL)(((tp)->t_flags) &= ~(0x20000000U)); |
517 | |
518 | if (tp->t_inpcb->inp_socket->so_options & SO_DEBUG0x0001) { |
519 | otp = tp; |
520 | ostate = tp->t_state; |
521 | } |
522 | tcp_timer_freesack(tp); |
523 | |
524 | maxidle = READ_ONCE(tcp_maxidle)({ typeof(tcp_maxidle) __tmp = *(volatile typeof(tcp_maxidle) *)&(tcp_maxidle); membar_datadep_consumer(); __tmp; }); |
525 | now = tcp_now(); |
526 | if (tp->t_state != TCPS_TIME_WAIT10 && |
527 | ((maxidle == 0) || ((now - tp->t_rcvtime) <= maxidle))) |
528 | TCP_TIMER_ARM(tp, TCPT_2MSL, tcp_keepintvl)do { (((tp)->t_flags) |= (0x04000000U << (3))); timeout_add_msec (&(tp)->t_timer[(3)], (tcp_keepintvl)); } while (0); |
529 | else |
530 | tp = tcp_close(tp); |
531 | if (otp) |
532 | tcp_trace(TA_TIMER5, ostate, tp, otp, NULL((void *)0), TCPT_2MSL3, 0); |
533 | out: |
534 | NET_UNLOCK()do { rw_exit_write(&netlock); } while (0); |
535 | } |
536 | |
537 | void |
538 | tcp_timer_reaper(void *arg) |
539 | { |
540 | struct tcpcb *tp = arg; |
541 | |
542 | /* |
543 | * This timer is necessary to delay the pool_put() after all timers |
544 | * have finished, even if they were sleeping to grab the net lock. |
545 | * Putting the pool_put() in a timer is sufficient as all timers run |
546 | * from the same timeout thread. Note that neither softnet thread nor |
547 | * user process may access the tcpcb after arming the reaper timer. |
548 | * Freeing may run in parallel as it does not grab the net lock. |
549 | */ |
550 | pool_put(&tcpcb_pool, tp); |
551 | tcpstat_inc(tcps_closed); |
552 | } |