RT-AC66 3.0.0.4.374.130 core
[tomato.git] / release / src-rt-6.x / linux / linux-2.6 / net / ipv4 / ipvs / ip_vs_proto_tcp.c
blobe65577a77006f3ed199f8e8c640a11123c97326e
1 /*
2 * ip_vs_proto_tcp.c: TCP load balancing support for IPVS
4 * Version: $Id: ip_vs_proto_tcp.c,v 1.3 2002/11/30 01:50:35 wensong Exp $
6 * Authors: Wensong Zhang <wensong@linuxvirtualserver.org>
7 * Julian Anastasov <ja@ssi.bg>
9 * This program is free software; you can redistribute it and/or
10 * modify it under the terms of the GNU General Public License
11 * as published by the Free Software Foundation; either version
12 * 2 of the License, or (at your option) any later version.
14 * Changes:
18 #include <linux/kernel.h>
19 #include <linux/ip.h>
20 #include <linux/tcp.h> /* for tcphdr */
21 #include <net/ip.h>
22 #include <net/tcp.h> /* for csum_tcpudp_magic */
23 #include <linux/netfilter_ipv4.h>
25 #include <net/ip_vs.h>
28 static struct ip_vs_conn *
29 tcp_conn_in_get(const struct sk_buff *skb, struct ip_vs_protocol *pp,
30 const struct iphdr *iph, unsigned int proto_off, int inverse)
32 __be16 _ports[2], *pptr;
34 pptr = skb_header_pointer(skb, proto_off, sizeof(_ports), _ports);
35 if (pptr == NULL)
36 return NULL;
38 if (likely(!inverse)) {
39 return ip_vs_conn_in_get(iph->protocol,
40 iph->saddr, pptr[0],
41 iph->daddr, pptr[1]);
42 } else {
43 return ip_vs_conn_in_get(iph->protocol,
44 iph->daddr, pptr[1],
45 iph->saddr, pptr[0]);
49 static struct ip_vs_conn *
50 tcp_conn_out_get(const struct sk_buff *skb, struct ip_vs_protocol *pp,
51 const struct iphdr *iph, unsigned int proto_off, int inverse)
53 __be16 _ports[2], *pptr;
55 pptr = skb_header_pointer(skb, proto_off, sizeof(_ports), _ports);
56 if (pptr == NULL)
57 return NULL;
59 if (likely(!inverse)) {
60 return ip_vs_conn_out_get(iph->protocol,
61 iph->saddr, pptr[0],
62 iph->daddr, pptr[1]);
63 } else {
64 return ip_vs_conn_out_get(iph->protocol,
65 iph->daddr, pptr[1],
66 iph->saddr, pptr[0]);
71 static int
72 tcp_conn_schedule(struct sk_buff *skb,
73 struct ip_vs_protocol *pp,
74 int *verdict, struct ip_vs_conn **cpp)
76 struct ip_vs_service *svc;
77 struct tcphdr _tcph, *th;
79 th = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_tcph), &_tcph);
80 if (th == NULL) {
81 *verdict = NF_DROP;
82 return 0;
85 if (th->syn &&
86 (svc = ip_vs_service_get(skb->mark, ip_hdr(skb)->protocol,
87 ip_hdr(skb)->daddr, th->dest))) {
88 if (ip_vs_todrop()) {
90 * It seems that we are very loaded.
91 * We have to drop this packet :(
93 ip_vs_service_put(svc);
94 *verdict = NF_DROP;
95 return 0;
99 * Let the virtual server select a real server for the
100 * incoming connection, and create a connection entry.
102 *cpp = ip_vs_schedule(svc, skb);
103 if (!*cpp) {
104 *verdict = ip_vs_leave(svc, skb, pp);
105 return 0;
107 ip_vs_service_put(svc);
109 return 1;
113 static inline void
114 tcp_fast_csum_update(struct tcphdr *tcph, __be32 oldip, __be32 newip,
115 __be16 oldport, __be16 newport)
117 tcph->check =
118 csum_fold(ip_vs_check_diff4(oldip, newip,
119 ip_vs_check_diff2(oldport, newport,
120 ~csum_unfold(tcph->check))));
124 static int
125 tcp_snat_handler(struct sk_buff **pskb,
126 struct ip_vs_protocol *pp, struct ip_vs_conn *cp)
128 struct tcphdr *tcph;
129 const unsigned int tcphoff = ip_hdrlen(*pskb);
131 /* csum_check requires unshared skb */
132 if (!ip_vs_make_skb_writable(pskb, tcphoff+sizeof(*tcph)))
133 return 0;
135 if (unlikely(cp->app != NULL)) {
136 /* Some checks before mangling */
137 if (pp->csum_check && !pp->csum_check(*pskb, pp))
138 return 0;
140 /* Call application helper if needed */
141 if (!ip_vs_app_pkt_out(cp, pskb))
142 return 0;
145 tcph = (void *)ip_hdr(*pskb) + tcphoff;
146 tcph->source = cp->vport;
148 /* Adjust TCP checksums */
149 if (!cp->app) {
150 /* Only port and addr are changed, do fast csum update */
151 tcp_fast_csum_update(tcph, cp->daddr, cp->vaddr,
152 cp->dport, cp->vport);
153 if ((*pskb)->ip_summed == CHECKSUM_COMPLETE)
154 (*pskb)->ip_summed = CHECKSUM_NONE;
155 } else {
156 /* full checksum calculation */
157 tcph->check = 0;
158 (*pskb)->csum = skb_checksum(*pskb, tcphoff,
159 (*pskb)->len - tcphoff, 0);
160 tcph->check = csum_tcpudp_magic(cp->vaddr, cp->caddr,
161 (*pskb)->len - tcphoff,
162 cp->protocol,
163 (*pskb)->csum);
164 IP_VS_DBG(11, "O-pkt: %s O-csum=%d (+%zd)\n",
165 pp->name, tcph->check,
166 (char*)&(tcph->check) - (char*)tcph);
168 return 1;
172 static int
173 tcp_dnat_handler(struct sk_buff **pskb,
174 struct ip_vs_protocol *pp, struct ip_vs_conn *cp)
176 struct tcphdr *tcph;
177 const unsigned int tcphoff = ip_hdrlen(*pskb);
179 /* csum_check requires unshared skb */
180 if (!ip_vs_make_skb_writable(pskb, tcphoff+sizeof(*tcph)))
181 return 0;
183 if (unlikely(cp->app != NULL)) {
184 /* Some checks before mangling */
185 if (pp->csum_check && !pp->csum_check(*pskb, pp))
186 return 0;
189 * Attempt ip_vs_app call.
190 * It will fix ip_vs_conn and iph ack_seq stuff
192 if (!ip_vs_app_pkt_in(cp, pskb))
193 return 0;
196 tcph = (void *)ip_hdr(*pskb) + tcphoff;
197 tcph->dest = cp->dport;
200 * Adjust TCP checksums
202 if (!cp->app) {
203 /* Only port and addr are changed, do fast csum update */
204 tcp_fast_csum_update(tcph, cp->vaddr, cp->daddr,
205 cp->vport, cp->dport);
206 if ((*pskb)->ip_summed == CHECKSUM_COMPLETE)
207 (*pskb)->ip_summed = CHECKSUM_NONE;
208 } else {
209 /* full checksum calculation */
210 tcph->check = 0;
211 (*pskb)->csum = skb_checksum(*pskb, tcphoff,
212 (*pskb)->len - tcphoff, 0);
213 tcph->check = csum_tcpudp_magic(cp->caddr, cp->daddr,
214 (*pskb)->len - tcphoff,
215 cp->protocol,
216 (*pskb)->csum);
217 (*pskb)->ip_summed = CHECKSUM_UNNECESSARY;
219 return 1;
223 static int
224 tcp_csum_check(struct sk_buff *skb, struct ip_vs_protocol *pp)
226 const unsigned int tcphoff = ip_hdrlen(skb);
228 switch (skb->ip_summed) {
229 case CHECKSUM_NONE:
230 skb->csum = skb_checksum(skb, tcphoff, skb->len - tcphoff, 0);
231 case CHECKSUM_COMPLETE:
232 if (csum_tcpudp_magic(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
233 skb->len - tcphoff,
234 ip_hdr(skb)->protocol, skb->csum)) {
235 IP_VS_DBG_RL_PKT(0, pp, skb, 0,
236 "Failed checksum for");
237 return 0;
239 break;
240 default:
241 /* No need to checksum. */
242 break;
245 return 1;
249 #define TCP_DIR_INPUT 0
250 #define TCP_DIR_OUTPUT 4
251 #define TCP_DIR_INPUT_ONLY 8
253 static const int tcp_state_off[IP_VS_DIR_LAST] = {
254 [IP_VS_DIR_INPUT] = TCP_DIR_INPUT,
255 [IP_VS_DIR_OUTPUT] = TCP_DIR_OUTPUT,
256 [IP_VS_DIR_INPUT_ONLY] = TCP_DIR_INPUT_ONLY,
260 * Timeout table[state]
262 static int tcp_timeouts[IP_VS_TCP_S_LAST+1] = {
263 [IP_VS_TCP_S_NONE] = 2*HZ,
264 [IP_VS_TCP_S_ESTABLISHED] = 15*60*HZ,
265 [IP_VS_TCP_S_SYN_SENT] = 2*60*HZ,
266 [IP_VS_TCP_S_SYN_RECV] = 1*60*HZ,
267 [IP_VS_TCP_S_FIN_WAIT] = 2*60*HZ,
268 [IP_VS_TCP_S_TIME_WAIT] = 2*60*HZ,
269 [IP_VS_TCP_S_CLOSE] = 10*HZ,
270 [IP_VS_TCP_S_CLOSE_WAIT] = 60*HZ,
271 [IP_VS_TCP_S_LAST_ACK] = 30*HZ,
272 [IP_VS_TCP_S_LISTEN] = 2*60*HZ,
273 [IP_VS_TCP_S_SYNACK] = 120*HZ,
274 [IP_VS_TCP_S_LAST] = 2*HZ,
277 static char * tcp_state_name_table[IP_VS_TCP_S_LAST+1] = {
278 [IP_VS_TCP_S_NONE] = "NONE",
279 [IP_VS_TCP_S_ESTABLISHED] = "ESTABLISHED",
280 [IP_VS_TCP_S_SYN_SENT] = "SYN_SENT",
281 [IP_VS_TCP_S_SYN_RECV] = "SYN_RECV",
282 [IP_VS_TCP_S_FIN_WAIT] = "FIN_WAIT",
283 [IP_VS_TCP_S_TIME_WAIT] = "TIME_WAIT",
284 [IP_VS_TCP_S_CLOSE] = "CLOSE",
285 [IP_VS_TCP_S_CLOSE_WAIT] = "CLOSE_WAIT",
286 [IP_VS_TCP_S_LAST_ACK] = "LAST_ACK",
287 [IP_VS_TCP_S_LISTEN] = "LISTEN",
288 [IP_VS_TCP_S_SYNACK] = "SYNACK",
289 [IP_VS_TCP_S_LAST] = "BUG!",
292 #define sNO IP_VS_TCP_S_NONE
293 #define sES IP_VS_TCP_S_ESTABLISHED
294 #define sSS IP_VS_TCP_S_SYN_SENT
295 #define sSR IP_VS_TCP_S_SYN_RECV
296 #define sFW IP_VS_TCP_S_FIN_WAIT
297 #define sTW IP_VS_TCP_S_TIME_WAIT
298 #define sCL IP_VS_TCP_S_CLOSE
299 #define sCW IP_VS_TCP_S_CLOSE_WAIT
300 #define sLA IP_VS_TCP_S_LAST_ACK
301 #define sLI IP_VS_TCP_S_LISTEN
302 #define sSA IP_VS_TCP_S_SYNACK
304 struct tcp_states_t {
305 int next_state[IP_VS_TCP_S_LAST];
308 static const char * tcp_state_name(int state)
310 if (state >= IP_VS_TCP_S_LAST)
311 return "ERR!";
312 return tcp_state_name_table[state] ? tcp_state_name_table[state] : "?";
315 static struct tcp_states_t tcp_states [] = {
316 /* INPUT */
317 /* sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
318 /*syn*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSR }},
319 /*fin*/ {{sCL, sCW, sSS, sTW, sTW, sTW, sCL, sCW, sLA, sLI, sTW }},
320 /*ack*/ {{sCL, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
321 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sSR }},
323 /* OUTPUT */
324 /* sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
325 /*syn*/ {{sSS, sES, sSS, sSR, sSS, sSS, sSS, sSS, sSS, sLI, sSR }},
326 /*fin*/ {{sTW, sFW, sSS, sTW, sFW, sTW, sCL, sTW, sLA, sLI, sTW }},
327 /*ack*/ {{sES, sES, sSS, sES, sFW, sTW, sCL, sCW, sLA, sES, sES }},
328 /*rst*/ {{sCL, sCL, sSS, sCL, sCL, sTW, sCL, sCL, sCL, sCL, sCL }},
330 /* INPUT-ONLY */
331 /* sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
332 /*syn*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSR }},
333 /*fin*/ {{sCL, sFW, sSS, sTW, sFW, sTW, sCL, sCW, sLA, sLI, sTW }},
334 /*ack*/ {{sCL, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
335 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
338 static struct tcp_states_t tcp_states_dos [] = {
339 /* INPUT */
340 /* sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
341 /*syn*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSA }},
342 /*fin*/ {{sCL, sCW, sSS, sTW, sTW, sTW, sCL, sCW, sLA, sLI, sSA }},
343 /*ack*/ {{sCL, sES, sSS, sSR, sFW, sTW, sCL, sCW, sCL, sLI, sSA }},
344 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
346 /* OUTPUT */
347 /* sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
348 /*syn*/ {{sSS, sES, sSS, sSA, sSS, sSS, sSS, sSS, sSS, sLI, sSA }},
349 /*fin*/ {{sTW, sFW, sSS, sTW, sFW, sTW, sCL, sTW, sLA, sLI, sTW }},
350 /*ack*/ {{sES, sES, sSS, sES, sFW, sTW, sCL, sCW, sLA, sES, sES }},
351 /*rst*/ {{sCL, sCL, sSS, sCL, sCL, sTW, sCL, sCL, sCL, sCL, sCL }},
353 /* INPUT-ONLY */
354 /* sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
355 /*syn*/ {{sSA, sES, sES, sSR, sSA, sSA, sSA, sSA, sSA, sSA, sSA }},
356 /*fin*/ {{sCL, sFW, sSS, sTW, sFW, sTW, sCL, sCW, sLA, sLI, sTW }},
357 /*ack*/ {{sCL, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
358 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
361 static struct tcp_states_t *tcp_state_table = tcp_states;
364 static void tcp_timeout_change(struct ip_vs_protocol *pp, int flags)
366 int on = (flags & 1); /* secure_tcp */
369 ** FIXME: change secure_tcp to independent sysctl var
370 ** or make it per-service or per-app because it is valid
371 ** for most if not for all of the applications. Something
372 ** like "capabilities" (flags) for each object.
374 tcp_state_table = (on? tcp_states_dos : tcp_states);
377 static int
378 tcp_set_state_timeout(struct ip_vs_protocol *pp, char *sname, int to)
380 return ip_vs_set_state_timeout(pp->timeout_table, IP_VS_TCP_S_LAST,
381 tcp_state_name_table, sname, to);
384 static inline int tcp_state_idx(struct tcphdr *th)
386 if (th->rst)
387 return 3;
388 if (th->syn)
389 return 0;
390 if (th->fin)
391 return 1;
392 if (th->ack)
393 return 2;
394 return -1;
397 static inline void
398 set_tcp_state(struct ip_vs_protocol *pp, struct ip_vs_conn *cp,
399 int direction, struct tcphdr *th)
401 int state_idx;
402 int new_state = IP_VS_TCP_S_CLOSE;
403 int state_off = tcp_state_off[direction];
406 * Update state offset to INPUT_ONLY if necessary
407 * or delete NO_OUTPUT flag if output packet detected
409 if (cp->flags & IP_VS_CONN_F_NOOUTPUT) {
410 if (state_off == TCP_DIR_OUTPUT)
411 cp->flags &= ~IP_VS_CONN_F_NOOUTPUT;
412 else
413 state_off = TCP_DIR_INPUT_ONLY;
416 if ((state_idx = tcp_state_idx(th)) < 0) {
417 IP_VS_DBG(8, "tcp_state_idx=%d!!!\n", state_idx);
418 goto tcp_state_out;
421 new_state = tcp_state_table[state_off+state_idx].next_state[cp->state];
423 tcp_state_out:
424 if (new_state != cp->state) {
425 struct ip_vs_dest *dest = cp->dest;
427 IP_VS_DBG(8, "%s %s [%c%c%c%c] %u.%u.%u.%u:%d->"
428 "%u.%u.%u.%u:%d state: %s->%s conn->refcnt:%d\n",
429 pp->name,
430 (state_off==TCP_DIR_OUTPUT)?"output ":"input ",
431 th->syn? 'S' : '.',
432 th->fin? 'F' : '.',
433 th->ack? 'A' : '.',
434 th->rst? 'R' : '.',
435 NIPQUAD(cp->daddr), ntohs(cp->dport),
436 NIPQUAD(cp->caddr), ntohs(cp->cport),
437 tcp_state_name(cp->state),
438 tcp_state_name(new_state),
439 atomic_read(&cp->refcnt));
440 if (dest) {
441 if (!(cp->flags & IP_VS_CONN_F_INACTIVE) &&
442 (new_state != IP_VS_TCP_S_ESTABLISHED)) {
443 atomic_dec(&dest->activeconns);
444 atomic_inc(&dest->inactconns);
445 cp->flags |= IP_VS_CONN_F_INACTIVE;
446 } else if ((cp->flags & IP_VS_CONN_F_INACTIVE) &&
447 (new_state == IP_VS_TCP_S_ESTABLISHED)) {
448 atomic_inc(&dest->activeconns);
449 atomic_dec(&dest->inactconns);
450 cp->flags &= ~IP_VS_CONN_F_INACTIVE;
455 cp->timeout = pp->timeout_table[cp->state = new_state];
460 * Handle state transitions
462 static int
463 tcp_state_transition(struct ip_vs_conn *cp, int direction,
464 const struct sk_buff *skb,
465 struct ip_vs_protocol *pp)
467 struct tcphdr _tcph, *th;
469 th = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_tcph), &_tcph);
470 if (th == NULL)
471 return 0;
473 spin_lock(&cp->lock);
474 set_tcp_state(pp, cp, direction, th);
475 spin_unlock(&cp->lock);
477 return 1;
482 * Hash table for TCP application incarnations
484 #define TCP_APP_TAB_BITS 4
485 #define TCP_APP_TAB_SIZE (1 << TCP_APP_TAB_BITS)
486 #define TCP_APP_TAB_MASK (TCP_APP_TAB_SIZE - 1)
488 static struct list_head tcp_apps[TCP_APP_TAB_SIZE];
489 static DEFINE_SPINLOCK(tcp_app_lock);
491 static inline __u16 tcp_app_hashkey(__be16 port)
493 return (((__force u16)port >> TCP_APP_TAB_BITS) ^ (__force u16)port)
494 & TCP_APP_TAB_MASK;
498 static int tcp_register_app(struct ip_vs_app *inc)
500 struct ip_vs_app *i;
501 __u16 hash;
502 __be16 port = inc->port;
503 int ret = 0;
505 hash = tcp_app_hashkey(port);
507 spin_lock_bh(&tcp_app_lock);
508 list_for_each_entry(i, &tcp_apps[hash], p_list) {
509 if (i->port == port) {
510 ret = -EEXIST;
511 goto out;
514 list_add(&inc->p_list, &tcp_apps[hash]);
515 atomic_inc(&ip_vs_protocol_tcp.appcnt);
517 out:
518 spin_unlock_bh(&tcp_app_lock);
519 return ret;
523 static void
524 tcp_unregister_app(struct ip_vs_app *inc)
526 spin_lock_bh(&tcp_app_lock);
527 atomic_dec(&ip_vs_protocol_tcp.appcnt);
528 list_del(&inc->p_list);
529 spin_unlock_bh(&tcp_app_lock);
533 static int
534 tcp_app_conn_bind(struct ip_vs_conn *cp)
536 int hash;
537 struct ip_vs_app *inc;
538 int result = 0;
540 /* Default binding: bind app only for NAT */
541 if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ)
542 return 0;
544 /* Lookup application incarnations and bind the right one */
545 hash = tcp_app_hashkey(cp->vport);
547 spin_lock(&tcp_app_lock);
548 list_for_each_entry(inc, &tcp_apps[hash], p_list) {
549 if (inc->port == cp->vport) {
550 if (unlikely(!ip_vs_app_inc_get(inc)))
551 break;
552 spin_unlock(&tcp_app_lock);
554 IP_VS_DBG(9, "%s: Binding conn %u.%u.%u.%u:%u->"
555 "%u.%u.%u.%u:%u to app %s on port %u\n",
556 __FUNCTION__,
557 NIPQUAD(cp->caddr), ntohs(cp->cport),
558 NIPQUAD(cp->vaddr), ntohs(cp->vport),
559 inc->name, ntohs(inc->port));
560 cp->app = inc;
561 if (inc->init_conn)
562 result = inc->init_conn(inc, cp);
563 goto out;
566 spin_unlock(&tcp_app_lock);
568 out:
569 return result;
574 * Set LISTEN timeout. (ip_vs_conn_put will setup timer)
576 void ip_vs_tcp_conn_listen(struct ip_vs_conn *cp)
578 spin_lock(&cp->lock);
579 cp->state = IP_VS_TCP_S_LISTEN;
580 cp->timeout = ip_vs_protocol_tcp.timeout_table[IP_VS_TCP_S_LISTEN];
581 spin_unlock(&cp->lock);
585 static void ip_vs_tcp_init(struct ip_vs_protocol *pp)
587 IP_VS_INIT_HASH_TABLE(tcp_apps);
588 pp->timeout_table = tcp_timeouts;
592 static void ip_vs_tcp_exit(struct ip_vs_protocol *pp)
597 struct ip_vs_protocol ip_vs_protocol_tcp = {
598 .name = "TCP",
599 .protocol = IPPROTO_TCP,
600 .dont_defrag = 0,
601 .appcnt = ATOMIC_INIT(0),
602 .init = ip_vs_tcp_init,
603 .exit = ip_vs_tcp_exit,
604 .register_app = tcp_register_app,
605 .unregister_app = tcp_unregister_app,
606 .conn_schedule = tcp_conn_schedule,
607 .conn_in_get = tcp_conn_in_get,
608 .conn_out_get = tcp_conn_out_get,
609 .snat_handler = tcp_snat_handler,
610 .dnat_handler = tcp_dnat_handler,
611 .csum_check = tcp_csum_check,
612 .state_name = tcp_state_name,
613 .state_transition = tcp_state_transition,
614 .app_conn_bind = tcp_app_conn_bind,
615 .debug_packet = ip_vs_tcpudp_debug_packet,
616 .timeout_change = tcp_timeout_change,
617 .set_state_timeout = tcp_set_state_timeout,