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xen: handle highmem pages correctly when shrinking a domain
[linux-2.6/mini2440.git] / net / netfilter / ipvs / ip_vs_proto_tcp.c
blob8cba41802850b041e5062c38f786da00f3ed6697
1 /*
2 * ip_vs_proto_tcp.c: TCP load balancing support for IPVS
3 *
4 * Authors: Wensong Zhang <wensong@linuxvirtualserver.org>
5 * Julian Anastasov <ja@ssi.bg>
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 * Changes:
13 *
14 */
15
16 #include <linux/kernel.h>
17 #include <linux/ip.h>
18 #include <linux/tcp.h> /* for tcphdr */
19 #include <net/ip.h>
20 #include <net/tcp.h> /* for csum_tcpudp_magic */
21 #include <net/ip6_checksum.h>
22 #include <linux/netfilter.h>
23 #include <linux/netfilter_ipv4.h>
24
25 #include <net/ip_vs.h>
26
27
28 static struct ip_vs_conn *
29 tcp_conn_in_get(int af, const struct sk_buff *skb, struct ip_vs_protocol *pp,
30 const struct ip_vs_iphdr *iph, unsigned int proto_off,
31 int inverse)
32 {
33 __be16 _ports[2], *pptr;
34
35 pptr = skb_header_pointer(skb, proto_off, sizeof(_ports), _ports);
36 if (pptr == NULL)
37 return NULL;
38
39 if (likely(!inverse)) {
40 return ip_vs_conn_in_get(af, iph->protocol,
41 &iph->saddr, pptr[0],
42 &iph->daddr, pptr[1]);
43 } else {
44 return ip_vs_conn_in_get(af, iph->protocol,
45 &iph->daddr, pptr[1],
46 &iph->saddr, pptr[0]);
47 }
48 }
49
50 static struct ip_vs_conn *
51 tcp_conn_out_get(int af, const struct sk_buff *skb, struct ip_vs_protocol *pp,
52 const struct ip_vs_iphdr *iph, unsigned int proto_off,
53 int inverse)
54 {
55 __be16 _ports[2], *pptr;
56
57 pptr = skb_header_pointer(skb, proto_off, sizeof(_ports), _ports);
58 if (pptr == NULL)
59 return NULL;
60
61 if (likely(!inverse)) {
62 return ip_vs_conn_out_get(af, iph->protocol,
63 &iph->saddr, pptr[0],
64 &iph->daddr, pptr[1]);
65 } else {
66 return ip_vs_conn_out_get(af, iph->protocol,
67 &iph->daddr, pptr[1],
68 &iph->saddr, pptr[0]);
69 }
70 }
71
72
73 static int
74 tcp_conn_schedule(int af, struct sk_buff *skb, struct ip_vs_protocol *pp,
75 int *verdict, struct ip_vs_conn **cpp)
76 {
77 struct ip_vs_service *svc;
78 struct tcphdr _tcph, *th;
79 struct ip_vs_iphdr iph;
80
81 ip_vs_fill_iphdr(af, skb_network_header(skb), &iph);
82
83 th = skb_header_pointer(skb, iph.len, sizeof(_tcph), &_tcph);
84 if (th == NULL) {
85 *verdict = NF_DROP;
86 return 0;
87 }
88
89 if (th->syn &&
90 (svc = ip_vs_service_get(af, skb->mark, iph.protocol, &iph.daddr,
91 th->dest))) {
92 if (ip_vs_todrop()) {
93 /*
94 * It seems that we are very loaded.
95 * We have to drop this packet :(
96 */
97 ip_vs_service_put(svc);
98 *verdict = NF_DROP;
99 return 0;
100 }
101
102 /*
103 * Let the virtual server select a real server for the
104 * incoming connection, and create a connection entry.
105 */
106 *cpp = ip_vs_schedule(svc, skb);
107 if (!*cpp) {
108 *verdict = ip_vs_leave(svc, skb, pp);
109 return 0;
110 }
111 ip_vs_service_put(svc);
112 }
113 return 1;
114 }
115
116
117 static inline void
118 tcp_fast_csum_update(int af, struct tcphdr *tcph,
119 const union nf_inet_addr *oldip,
120 const union nf_inet_addr *newip,
121 __be16 oldport, __be16 newport)
122 {
123 #ifdef CONFIG_IP_VS_IPV6
124 if (af == AF_INET6)
125 tcph->check =
126 csum_fold(ip_vs_check_diff16(oldip->ip6, newip->ip6,
127 ip_vs_check_diff2(oldport, newport,
128 ~csum_unfold(tcph->check))));
129 else
130 #endif
131 tcph->check =
132 csum_fold(ip_vs_check_diff4(oldip->ip, newip->ip,
133 ip_vs_check_diff2(oldport, newport,
134 ~csum_unfold(tcph->check))));
135 }
136
137
138 static inline void
139 tcp_partial_csum_update(int af, struct tcphdr *tcph,
140 const union nf_inet_addr *oldip,
141 const union nf_inet_addr *newip,
142 __be16 oldlen, __be16 newlen)
143 {
144 #ifdef CONFIG_IP_VS_IPV6
145 if (af == AF_INET6)
146 tcph->check =
147 csum_fold(ip_vs_check_diff16(oldip->ip6, newip->ip6,
148 ip_vs_check_diff2(oldlen, newlen,
149 ~csum_unfold(tcph->check))));
150 else
151 #endif
152 tcph->check =
153 csum_fold(ip_vs_check_diff4(oldip->ip, newip->ip,
154 ip_vs_check_diff2(oldlen, newlen,
155 ~csum_unfold(tcph->check))));
156 }
157
158
159 static int
160 tcp_snat_handler(struct sk_buff *skb,
161 struct ip_vs_protocol *pp, struct ip_vs_conn *cp)
162 {
163 struct tcphdr *tcph;
164 unsigned int tcphoff;
165 int oldlen;
166
167 #ifdef CONFIG_IP_VS_IPV6
168 if (cp->af == AF_INET6)
169 tcphoff = sizeof(struct ipv6hdr);
170 else
171 #endif
172 tcphoff = ip_hdrlen(skb);
173 oldlen = skb->len - tcphoff;
174
175 /* csum_check requires unshared skb */
176 if (!skb_make_writable(skb, tcphoff+sizeof(*tcph)))
177 return 0;
178
179 if (unlikely(cp->app != NULL)) {
180 /* Some checks before mangling */
181 if (pp->csum_check && !pp->csum_check(cp->af, skb, pp))
182 return 0;
183
184 /* Call application helper if needed */
185 if (!ip_vs_app_pkt_out(cp, skb))
186 return 0;
187 }
188
189 tcph = (void *)skb_network_header(skb) + tcphoff;
190 tcph->source = cp->vport;
191
192 /* Adjust TCP checksums */
193 if (skb->ip_summed == CHECKSUM_PARTIAL) {
194 tcp_partial_csum_update(cp->af, tcph, &cp->daddr, &cp->vaddr,
195 htons(oldlen),
196 htons(skb->len - tcphoff));
197 } else if (!cp->app) {
198 /* Only port and addr are changed, do fast csum update */
199 tcp_fast_csum_update(cp->af, tcph, &cp->daddr, &cp->vaddr,
200 cp->dport, cp->vport);
201 if (skb->ip_summed == CHECKSUM_COMPLETE)
202 skb->ip_summed = CHECKSUM_NONE;
203 } else {
204 /* full checksum calculation */
205 tcph->check = 0;
206 skb->csum = skb_checksum(skb, tcphoff, skb->len - tcphoff, 0);
207 #ifdef CONFIG_IP_VS_IPV6
208 if (cp->af == AF_INET6)
209 tcph->check = csum_ipv6_magic(&cp->vaddr.in6,
210 &cp->caddr.in6,
211 skb->len - tcphoff,
212 cp->protocol, skb->csum);
213 else
214 #endif
215 tcph->check = csum_tcpudp_magic(cp->vaddr.ip,
216 cp->caddr.ip,
217 skb->len - tcphoff,
218 cp->protocol,
219 skb->csum);
220
221 IP_VS_DBG(11, "O-pkt: %s O-csum=%d (+%zd)\n",
222 pp->name, tcph->check,
223 (char*)&(tcph->check) - (char*)tcph);
224 }
225 return 1;
226 }
227
228
229 static int
230 tcp_dnat_handler(struct sk_buff *skb,
231 struct ip_vs_protocol *pp, struct ip_vs_conn *cp)
232 {
233 struct tcphdr *tcph;
234 unsigned int tcphoff;
235 int oldlen;
236
237 #ifdef CONFIG_IP_VS_IPV6
238 if (cp->af == AF_INET6)
239 tcphoff = sizeof(struct ipv6hdr);
240 else
241 #endif
242 tcphoff = ip_hdrlen(skb);
243 oldlen = skb->len - tcphoff;
244
245 /* csum_check requires unshared skb */
246 if (!skb_make_writable(skb, tcphoff+sizeof(*tcph)))
247 return 0;
248
249 if (unlikely(cp->app != NULL)) {
250 /* Some checks before mangling */
251 if (pp->csum_check && !pp->csum_check(cp->af, skb, pp))
252 return 0;
253
254 /*
255 * Attempt ip_vs_app call.
256 * It will fix ip_vs_conn and iph ack_seq stuff
257 */
258 if (!ip_vs_app_pkt_in(cp, skb))
259 return 0;
260 }
261
262 tcph = (void *)skb_network_header(skb) + tcphoff;
263 tcph->dest = cp->dport;
264
265 /*
266 * Adjust TCP checksums
267 */
268 if (skb->ip_summed == CHECKSUM_PARTIAL) {
269 tcp_partial_csum_update(cp->af, tcph, &cp->daddr, &cp->vaddr,
270 htons(oldlen),
271 htons(skb->len - tcphoff));
272 } else if (!cp->app) {
273 /* Only port and addr are changed, do fast csum update */
274 tcp_fast_csum_update(cp->af, tcph, &cp->vaddr, &cp->daddr,
275 cp->vport, cp->dport);
276 if (skb->ip_summed == CHECKSUM_COMPLETE)
277 skb->ip_summed = CHECKSUM_NONE;
278 } else {
279 /* full checksum calculation */
280 tcph->check = 0;
281 skb->csum = skb_checksum(skb, tcphoff, skb->len - tcphoff, 0);
282 #ifdef CONFIG_IP_VS_IPV6
283 if (cp->af == AF_INET6)
284 tcph->check = csum_ipv6_magic(&cp->caddr.in6,
285 &cp->daddr.in6,
286 skb->len - tcphoff,
287 cp->protocol, skb->csum);
288 else
289 #endif
290 tcph->check = csum_tcpudp_magic(cp->caddr.ip,
291 cp->daddr.ip,
292 skb->len - tcphoff,
293 cp->protocol,
294 skb->csum);
295 skb->ip_summed = CHECKSUM_UNNECESSARY;
296 }
297 return 1;
298 }
299
300
301 static int
302 tcp_csum_check(int af, struct sk_buff *skb, struct ip_vs_protocol *pp)
303 {
304 unsigned int tcphoff;
305
306 #ifdef CONFIG_IP_VS_IPV6
307 if (af == AF_INET6)
308 tcphoff = sizeof(struct ipv6hdr);
309 else
310 #endif
311 tcphoff = ip_hdrlen(skb);
312
313 switch (skb->ip_summed) {
314 case CHECKSUM_NONE:
315 skb->csum = skb_checksum(skb, tcphoff, skb->len - tcphoff, 0);
316 case CHECKSUM_COMPLETE:
317 #ifdef CONFIG_IP_VS_IPV6
318 if (af == AF_INET6) {
319 if (csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
320 &ipv6_hdr(skb)->daddr,
321 skb->len - tcphoff,
322 ipv6_hdr(skb)->nexthdr,
323 skb->csum)) {
324 IP_VS_DBG_RL_PKT(0, pp, skb, 0,
325 "Failed checksum for");
326 return 0;
327 }
328 } else
329 #endif
330 if (csum_tcpudp_magic(ip_hdr(skb)->saddr,
331 ip_hdr(skb)->daddr,
332 skb->len - tcphoff,
333 ip_hdr(skb)->protocol,
334 skb->csum)) {
335 IP_VS_DBG_RL_PKT(0, pp, skb, 0,
336 "Failed checksum for");
337 return 0;
338 }
339 break;
340 default:
341 /* No need to checksum. */
342 break;
343 }
344
345 return 1;
346 }
347
348
349 #define TCP_DIR_INPUT 0
350 #define TCP_DIR_OUTPUT 4
351 #define TCP_DIR_INPUT_ONLY 8
352
353 static const int tcp_state_off[IP_VS_DIR_LAST] = {
354 [IP_VS_DIR_INPUT] = TCP_DIR_INPUT,
355 [IP_VS_DIR_OUTPUT] = TCP_DIR_OUTPUT,
356 [IP_VS_DIR_INPUT_ONLY] = TCP_DIR_INPUT_ONLY,
357 };
358
359 /*
360 * Timeout table[state]
361 */
362 static int tcp_timeouts[IP_VS_TCP_S_LAST+1] = {
363 [IP_VS_TCP_S_NONE] = 2*HZ,
364 [IP_VS_TCP_S_ESTABLISHED] = 15*60*HZ,
365 [IP_VS_TCP_S_SYN_SENT] = 2*60*HZ,
366 [IP_VS_TCP_S_SYN_RECV] = 1*60*HZ,
367 [IP_VS_TCP_S_FIN_WAIT] = 2*60*HZ,
368 [IP_VS_TCP_S_TIME_WAIT] = 2*60*HZ,
369 [IP_VS_TCP_S_CLOSE] = 10*HZ,
370 [IP_VS_TCP_S_CLOSE_WAIT] = 60*HZ,
371 [IP_VS_TCP_S_LAST_ACK] = 30*HZ,
372 [IP_VS_TCP_S_LISTEN] = 2*60*HZ,
373 [IP_VS_TCP_S_SYNACK] = 120*HZ,
374 [IP_VS_TCP_S_LAST] = 2*HZ,
375 };
376
377 static char * tcp_state_name_table[IP_VS_TCP_S_LAST+1] = {
378 [IP_VS_TCP_S_NONE] = "NONE",
379 [IP_VS_TCP_S_ESTABLISHED] = "ESTABLISHED",
380 [IP_VS_TCP_S_SYN_SENT] = "SYN_SENT",
381 [IP_VS_TCP_S_SYN_RECV] = "SYN_RECV",
382 [IP_VS_TCP_S_FIN_WAIT] = "FIN_WAIT",
383 [IP_VS_TCP_S_TIME_WAIT] = "TIME_WAIT",
384 [IP_VS_TCP_S_CLOSE] = "CLOSE",
385 [IP_VS_TCP_S_CLOSE_WAIT] = "CLOSE_WAIT",
386 [IP_VS_TCP_S_LAST_ACK] = "LAST_ACK",
387 [IP_VS_TCP_S_LISTEN] = "LISTEN",
388 [IP_VS_TCP_S_SYNACK] = "SYNACK",
389 [IP_VS_TCP_S_LAST] = "BUG!",
390 };
391
392 #define sNO IP_VS_TCP_S_NONE
393 #define sES IP_VS_TCP_S_ESTABLISHED
394 #define sSS IP_VS_TCP_S_SYN_SENT
395 #define sSR IP_VS_TCP_S_SYN_RECV
396 #define sFW IP_VS_TCP_S_FIN_WAIT
397 #define sTW IP_VS_TCP_S_TIME_WAIT
398 #define sCL IP_VS_TCP_S_CLOSE
399 #define sCW IP_VS_TCP_S_CLOSE_WAIT
400 #define sLA IP_VS_TCP_S_LAST_ACK
401 #define sLI IP_VS_TCP_S_LISTEN
402 #define sSA IP_VS_TCP_S_SYNACK
403
404 struct tcp_states_t {
405 int next_state[IP_VS_TCP_S_LAST];
406 };
407
408 static const char * tcp_state_name(int state)
409 {
410 if (state >= IP_VS_TCP_S_LAST)
411 return "ERR!";
412 return tcp_state_name_table[state] ? tcp_state_name_table[state] : "?";
413 }
414
415 static struct tcp_states_t tcp_states [] = {
416 /* INPUT */
417 /* sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
418 /*syn*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSR }},
419 /*fin*/ {{sCL, sCW, sSS, sTW, sTW, sTW, sCL, sCW, sLA, sLI, sTW }},
420 /*ack*/ {{sCL, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
421 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sSR }},
422
423 /* OUTPUT */
424 /* sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
425 /*syn*/ {{sSS, sES, sSS, sSR, sSS, sSS, sSS, sSS, sSS, sLI, sSR }},
426 /*fin*/ {{sTW, sFW, sSS, sTW, sFW, sTW, sCL, sTW, sLA, sLI, sTW }},
427 /*ack*/ {{sES, sES, sSS, sES, sFW, sTW, sCL, sCW, sLA, sES, sES }},
428 /*rst*/ {{sCL, sCL, sSS, sCL, sCL, sTW, sCL, sCL, sCL, sCL, sCL }},
429
430 /* INPUT-ONLY */
431 /* sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
432 /*syn*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSR }},
433 /*fin*/ {{sCL, sFW, sSS, sTW, sFW, sTW, sCL, sCW, sLA, sLI, sTW }},
434 /*ack*/ {{sCL, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
435 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
436 };
437
438 static struct tcp_states_t tcp_states_dos [] = {
439 /* INPUT */
440 /* sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
441 /*syn*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSA }},
442 /*fin*/ {{sCL, sCW, sSS, sTW, sTW, sTW, sCL, sCW, sLA, sLI, sSA }},
443 /*ack*/ {{sCL, sES, sSS, sSR, sFW, sTW, sCL, sCW, sCL, sLI, sSA }},
444 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
445
446 /* OUTPUT */
447 /* sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
448 /*syn*/ {{sSS, sES, sSS, sSA, sSS, sSS, sSS, sSS, sSS, sLI, sSA }},
449 /*fin*/ {{sTW, sFW, sSS, sTW, sFW, sTW, sCL, sTW, sLA, sLI, sTW }},
450 /*ack*/ {{sES, sES, sSS, sES, sFW, sTW, sCL, sCW, sLA, sES, sES }},
451 /*rst*/ {{sCL, sCL, sSS, sCL, sCL, sTW, sCL, sCL, sCL, sCL, sCL }},
452
453 /* INPUT-ONLY */
454 /* sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
455 /*syn*/ {{sSA, sES, sES, sSR, sSA, sSA, sSA, sSA, sSA, sSA, sSA }},
456 /*fin*/ {{sCL, sFW, sSS, sTW, sFW, sTW, sCL, sCW, sLA, sLI, sTW }},
457 /*ack*/ {{sCL, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
458 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
459 };
460
461 static struct tcp_states_t *tcp_state_table = tcp_states;
462
463
464 static void tcp_timeout_change(struct ip_vs_protocol *pp, int flags)
465 {
466 int on = (flags & 1); /* secure_tcp */
467
468 /*
469 ** FIXME: change secure_tcp to independent sysctl var
470 ** or make it per-service or per-app because it is valid
471 ** for most if not for all of the applications. Something
472 ** like "capabilities" (flags) for each object.
473 */
474 tcp_state_table = (on? tcp_states_dos : tcp_states);
475 }
476
477 static int
478 tcp_set_state_timeout(struct ip_vs_protocol *pp, char *sname, int to)
479 {
480 return ip_vs_set_state_timeout(pp->timeout_table, IP_VS_TCP_S_LAST,
481 tcp_state_name_table, sname, to);
482 }
483
484 static inline int tcp_state_idx(struct tcphdr *th)
485 {
486 if (th->rst)
487 return 3;
488 if (th->syn)
489 return 0;
490 if (th->fin)
491 return 1;
492 if (th->ack)
493 return 2;
494 return -1;
495 }
496
497 static inline void
498 set_tcp_state(struct ip_vs_protocol *pp, struct ip_vs_conn *cp,
499 int direction, struct tcphdr *th)
500 {
501 int state_idx;
502 int new_state = IP_VS_TCP_S_CLOSE;
503 int state_off = tcp_state_off[direction];
504
505 /*
506 * Update state offset to INPUT_ONLY if necessary
507 * or delete NO_OUTPUT flag if output packet detected
508 */
509 if (cp->flags & IP_VS_CONN_F_NOOUTPUT) {
510 if (state_off == TCP_DIR_OUTPUT)
511 cp->flags &= ~IP_VS_CONN_F_NOOUTPUT;
512 else
513 state_off = TCP_DIR_INPUT_ONLY;
514 }
515
516 if ((state_idx = tcp_state_idx(th)) < 0) {
517 IP_VS_DBG(8, "tcp_state_idx=%d!!!\n", state_idx);
518 goto tcp_state_out;
519 }
520
521 new_state = tcp_state_table[state_off+state_idx].next_state[cp->state];
522
523 tcp_state_out:
524 if (new_state != cp->state) {
525 struct ip_vs_dest *dest = cp->dest;
526
527 IP_VS_DBG_BUF(8, "%s %s [%c%c%c%c] %s:%d->"
528 "%s:%d state: %s->%s conn->refcnt:%d\n",
529 pp->name,
530 ((state_off == TCP_DIR_OUTPUT) ?
531 "output " : "input "),
532 th->syn ? 'S' : '.',
533 th->fin ? 'F' : '.',
534 th->ack ? 'A' : '.',
535 th->rst ? 'R' : '.',
536 IP_VS_DBG_ADDR(cp->af, &cp->daddr),
537 ntohs(cp->dport),
538 IP_VS_DBG_ADDR(cp->af, &cp->caddr),
539 ntohs(cp->cport),
540 tcp_state_name(cp->state),
541 tcp_state_name(new_state),
542 atomic_read(&cp->refcnt));
543
544 if (dest) {
545 if (!(cp->flags & IP_VS_CONN_F_INACTIVE) &&
546 (new_state != IP_VS_TCP_S_ESTABLISHED)) {
547 atomic_dec(&dest->activeconns);
548 atomic_inc(&dest->inactconns);
549 cp->flags |= IP_VS_CONN_F_INACTIVE;
550 } else if ((cp->flags & IP_VS_CONN_F_INACTIVE) &&
551 (new_state == IP_VS_TCP_S_ESTABLISHED)) {
552 atomic_inc(&dest->activeconns);
553 atomic_dec(&dest->inactconns);
554 cp->flags &= ~IP_VS_CONN_F_INACTIVE;
555 }
556 }
557 }
558
559 cp->timeout = pp->timeout_table[cp->state = new_state];
560 }
561
562
563 /*
564 * Handle state transitions
565 */
566 static int
567 tcp_state_transition(struct ip_vs_conn *cp, int direction,
568 const struct sk_buff *skb,
569 struct ip_vs_protocol *pp)
570 {
571 struct tcphdr _tcph, *th;
572
573 #ifdef CONFIG_IP_VS_IPV6
574 int ihl = cp->af == AF_INET ? ip_hdrlen(skb) : sizeof(struct ipv6hdr);
575 #else
576 int ihl = ip_hdrlen(skb);
577 #endif
578
579 th = skb_header_pointer(skb, ihl, sizeof(_tcph), &_tcph);
580 if (th == NULL)
581 return 0;
582
583 spin_lock(&cp->lock);
584 set_tcp_state(pp, cp, direction, th);
585 spin_unlock(&cp->lock);
586
587 return 1;
588 }
589
590
591 /*
592 * Hash table for TCP application incarnations
593 */
594 #define TCP_APP_TAB_BITS 4
595 #define TCP_APP_TAB_SIZE (1 << TCP_APP_TAB_BITS)
596 #define TCP_APP_TAB_MASK (TCP_APP_TAB_SIZE - 1)
597
598 static struct list_head tcp_apps[TCP_APP_TAB_SIZE];
599 static DEFINE_SPINLOCK(tcp_app_lock);
600
601 static inline __u16 tcp_app_hashkey(__be16 port)
602 {
603 return (((__force u16)port >> TCP_APP_TAB_BITS) ^ (__force u16)port)
604 & TCP_APP_TAB_MASK;
605 }
606
607
608 static int tcp_register_app(struct ip_vs_app *inc)
609 {
610 struct ip_vs_app *i;
611 __u16 hash;
612 __be16 port = inc->port;
613 int ret = 0;
614
615 hash = tcp_app_hashkey(port);
616
617 spin_lock_bh(&tcp_app_lock);
618 list_for_each_entry(i, &tcp_apps[hash], p_list) {
619 if (i->port == port) {
620 ret = -EEXIST;
621 goto out;
622 }
623 }
624 list_add(&inc->p_list, &tcp_apps[hash]);
625 atomic_inc(&ip_vs_protocol_tcp.appcnt);
626
627 out:
628 spin_unlock_bh(&tcp_app_lock);
629 return ret;
630 }
631
632
633 static void
634 tcp_unregister_app(struct ip_vs_app *inc)
635 {
636 spin_lock_bh(&tcp_app_lock);
637 atomic_dec(&ip_vs_protocol_tcp.appcnt);
638 list_del(&inc->p_list);
639 spin_unlock_bh(&tcp_app_lock);
640 }
641
642
643 static int
644 tcp_app_conn_bind(struct ip_vs_conn *cp)
645 {
646 int hash;
647 struct ip_vs_app *inc;
648 int result = 0;
649
650 /* Default binding: bind app only for NAT */
651 if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ)
652 return 0;
653
654 /* Lookup application incarnations and bind the right one */
655 hash = tcp_app_hashkey(cp->vport);
656
657 spin_lock(&tcp_app_lock);
658 list_for_each_entry(inc, &tcp_apps[hash], p_list) {
659 if (inc->port == cp->vport) {
660 if (unlikely(!ip_vs_app_inc_get(inc)))
661 break;
662 spin_unlock(&tcp_app_lock);
663
664 IP_VS_DBG_BUF(9, "%s: Binding conn %s:%u->"
665 "%s:%u to app %s on port %u\n",
666 __func__,
667 IP_VS_DBG_ADDR(cp->af, &cp->caddr),
668 ntohs(cp->cport),
669 IP_VS_DBG_ADDR(cp->af, &cp->vaddr),
670 ntohs(cp->vport),
671 inc->name, ntohs(inc->port));
672
673 cp->app = inc;
674 if (inc->init_conn)
675 result = inc->init_conn(inc, cp);
676 goto out;
677 }
678 }
679 spin_unlock(&tcp_app_lock);
680
681 out:
682 return result;
683 }
684
685
686 /*
687 * Set LISTEN timeout. (ip_vs_conn_put will setup timer)
688 */
689 void ip_vs_tcp_conn_listen(struct ip_vs_conn *cp)
690 {
691 spin_lock(&cp->lock);
692 cp->state = IP_VS_TCP_S_LISTEN;
693 cp->timeout = ip_vs_protocol_tcp.timeout_table[IP_VS_TCP_S_LISTEN];
694 spin_unlock(&cp->lock);
695 }
696
697
698 static void ip_vs_tcp_init(struct ip_vs_protocol *pp)
699 {
700 IP_VS_INIT_HASH_TABLE(tcp_apps);
701 pp->timeout_table = tcp_timeouts;
702 }
703
704
705 static void ip_vs_tcp_exit(struct ip_vs_protocol *pp)
706 {
707 }
708
709
710 struct ip_vs_protocol ip_vs_protocol_tcp = {
711 .name = "TCP",
712 .protocol = IPPROTO_TCP,
713 .num_states = IP_VS_TCP_S_LAST,
714 .dont_defrag = 0,
715 .appcnt = ATOMIC_INIT(0),
716 .init = ip_vs_tcp_init,
717 .exit = ip_vs_tcp_exit,
718 .register_app = tcp_register_app,
719 .unregister_app = tcp_unregister_app,
720 .conn_schedule = tcp_conn_schedule,
721 .conn_in_get = tcp_conn_in_get,
722 .conn_out_get = tcp_conn_out_get,
723 .snat_handler = tcp_snat_handler,
724 .dnat_handler = tcp_dnat_handler,
725 .csum_check = tcp_csum_check,
726 .state_name = tcp_state_name,
727 .state_transition = tcp_state_transition,
728 .app_conn_bind = tcp_app_conn_bind,
729 .debug_packet = ip_vs_tcpudp_debug_packet,
730 .timeout_change = tcp_timeout_change,
731 .set_state_timeout = tcp_set_state_timeout,
732 };
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