Driver core: Fix cleanup when failing device_add().
[wrt350n-kernel.git] / net / ipv4 / ipvs / ip_vs_proto_tcp.c
blob12dc0d640b6d4feecd87a63ff676eb476e6f909c
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.h>
24 #include <linux/netfilter_ipv4.h>
26 #include <net/ip_vs.h>
29 static struct ip_vs_conn *
30 tcp_conn_in_get(const struct sk_buff *skb, struct ip_vs_protocol *pp,
31 const struct iphdr *iph, unsigned int proto_off, int inverse)
33 __be16 _ports[2], *pptr;
35 pptr = skb_header_pointer(skb, proto_off, sizeof(_ports), _ports);
36 if (pptr == NULL)
37 return NULL;
39 if (likely(!inverse)) {
40 return ip_vs_conn_in_get(iph->protocol,
41 iph->saddr, pptr[0],
42 iph->daddr, pptr[1]);
43 } else {
44 return ip_vs_conn_in_get(iph->protocol,
45 iph->daddr, pptr[1],
46 iph->saddr, pptr[0]);
50 static struct ip_vs_conn *
51 tcp_conn_out_get(const struct sk_buff *skb, struct ip_vs_protocol *pp,
52 const struct iphdr *iph, unsigned int proto_off, int inverse)
54 __be16 _ports[2], *pptr;
56 pptr = skb_header_pointer(skb, proto_off, sizeof(_ports), _ports);
57 if (pptr == NULL)
58 return NULL;
60 if (likely(!inverse)) {
61 return ip_vs_conn_out_get(iph->protocol,
62 iph->saddr, pptr[0],
63 iph->daddr, pptr[1]);
64 } else {
65 return ip_vs_conn_out_get(iph->protocol,
66 iph->daddr, pptr[1],
67 iph->saddr, pptr[0]);
72 static int
73 tcp_conn_schedule(struct sk_buff *skb,
74 struct ip_vs_protocol *pp,
75 int *verdict, struct ip_vs_conn **cpp)
77 struct ip_vs_service *svc;
78 struct tcphdr _tcph, *th;
80 th = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_tcph), &_tcph);
81 if (th == NULL) {
82 *verdict = NF_DROP;
83 return 0;
86 if (th->syn &&
87 (svc = ip_vs_service_get(skb->mark, ip_hdr(skb)->protocol,
88 ip_hdr(skb)->daddr, th->dest))) {
89 if (ip_vs_todrop()) {
91 * It seems that we are very loaded.
92 * We have to drop this packet :(
94 ip_vs_service_put(svc);
95 *verdict = NF_DROP;
96 return 0;
100 * Let the virtual server select a real server for the
101 * incoming connection, and create a connection entry.
103 *cpp = ip_vs_schedule(svc, skb);
104 if (!*cpp) {
105 *verdict = ip_vs_leave(svc, skb, pp);
106 return 0;
108 ip_vs_service_put(svc);
110 return 1;
114 static inline void
115 tcp_fast_csum_update(struct tcphdr *tcph, __be32 oldip, __be32 newip,
116 __be16 oldport, __be16 newport)
118 tcph->check =
119 csum_fold(ip_vs_check_diff4(oldip, newip,
120 ip_vs_check_diff2(oldport, newport,
121 ~csum_unfold(tcph->check))));
125 static int
126 tcp_snat_handler(struct sk_buff *skb,
127 struct ip_vs_protocol *pp, struct ip_vs_conn *cp)
129 struct tcphdr *tcph;
130 const unsigned int tcphoff = ip_hdrlen(skb);
132 /* csum_check requires unshared skb */
133 if (!skb_make_writable(skb, tcphoff+sizeof(*tcph)))
134 return 0;
136 if (unlikely(cp->app != NULL)) {
137 /* Some checks before mangling */
138 if (pp->csum_check && !pp->csum_check(skb, pp))
139 return 0;
141 /* Call application helper if needed */
142 if (!ip_vs_app_pkt_out(cp, skb))
143 return 0;
146 tcph = (void *)ip_hdr(skb) + tcphoff;
147 tcph->source = cp->vport;
149 /* Adjust TCP checksums */
150 if (!cp->app) {
151 /* Only port and addr are changed, do fast csum update */
152 tcp_fast_csum_update(tcph, cp->daddr, cp->vaddr,
153 cp->dport, cp->vport);
154 if (skb->ip_summed == CHECKSUM_COMPLETE)
155 skb->ip_summed = CHECKSUM_NONE;
156 } else {
157 /* full checksum calculation */
158 tcph->check = 0;
159 skb->csum = skb_checksum(skb, tcphoff, skb->len - tcphoff, 0);
160 tcph->check = csum_tcpudp_magic(cp->vaddr, cp->caddr,
161 skb->len - tcphoff,
162 cp->protocol, skb->csum);
163 IP_VS_DBG(11, "O-pkt: %s O-csum=%d (+%zd)\n",
164 pp->name, tcph->check,
165 (char*)&(tcph->check) - (char*)tcph);
167 return 1;
171 static int
172 tcp_dnat_handler(struct sk_buff *skb,
173 struct ip_vs_protocol *pp, struct ip_vs_conn *cp)
175 struct tcphdr *tcph;
176 const unsigned int tcphoff = ip_hdrlen(skb);
178 /* csum_check requires unshared skb */
179 if (!skb_make_writable(skb, tcphoff+sizeof(*tcph)))
180 return 0;
182 if (unlikely(cp->app != NULL)) {
183 /* Some checks before mangling */
184 if (pp->csum_check && !pp->csum_check(skb, pp))
185 return 0;
188 * Attempt ip_vs_app call.
189 * It will fix ip_vs_conn and iph ack_seq stuff
191 if (!ip_vs_app_pkt_in(cp, skb))
192 return 0;
195 tcph = (void *)ip_hdr(skb) + tcphoff;
196 tcph->dest = cp->dport;
199 * Adjust TCP checksums
201 if (!cp->app) {
202 /* Only port and addr are changed, do fast csum update */
203 tcp_fast_csum_update(tcph, cp->vaddr, cp->daddr,
204 cp->vport, cp->dport);
205 if (skb->ip_summed == CHECKSUM_COMPLETE)
206 skb->ip_summed = CHECKSUM_NONE;
207 } else {
208 /* full checksum calculation */
209 tcph->check = 0;
210 skb->csum = skb_checksum(skb, tcphoff, skb->len - tcphoff, 0);
211 tcph->check = csum_tcpudp_magic(cp->caddr, cp->daddr,
212 skb->len - tcphoff,
213 cp->protocol, skb->csum);
214 skb->ip_summed = CHECKSUM_UNNECESSARY;
216 return 1;
220 static int
221 tcp_csum_check(struct sk_buff *skb, struct ip_vs_protocol *pp)
223 const unsigned int tcphoff = ip_hdrlen(skb);
225 switch (skb->ip_summed) {
226 case CHECKSUM_NONE:
227 skb->csum = skb_checksum(skb, tcphoff, skb->len - tcphoff, 0);
228 case CHECKSUM_COMPLETE:
229 if (csum_tcpudp_magic(ip_hdr(skb)->saddr, ip_hdr(skb)->daddr,
230 skb->len - tcphoff,
231 ip_hdr(skb)->protocol, skb->csum)) {
232 IP_VS_DBG_RL_PKT(0, pp, skb, 0,
233 "Failed checksum for");
234 return 0;
236 break;
237 default:
238 /* No need to checksum. */
239 break;
242 return 1;
246 #define TCP_DIR_INPUT 0
247 #define TCP_DIR_OUTPUT 4
248 #define TCP_DIR_INPUT_ONLY 8
250 static const int tcp_state_off[IP_VS_DIR_LAST] = {
251 [IP_VS_DIR_INPUT] = TCP_DIR_INPUT,
252 [IP_VS_DIR_OUTPUT] = TCP_DIR_OUTPUT,
253 [IP_VS_DIR_INPUT_ONLY] = TCP_DIR_INPUT_ONLY,
257 * Timeout table[state]
259 static int tcp_timeouts[IP_VS_TCP_S_LAST+1] = {
260 [IP_VS_TCP_S_NONE] = 2*HZ,
261 [IP_VS_TCP_S_ESTABLISHED] = 15*60*HZ,
262 [IP_VS_TCP_S_SYN_SENT] = 2*60*HZ,
263 [IP_VS_TCP_S_SYN_RECV] = 1*60*HZ,
264 [IP_VS_TCP_S_FIN_WAIT] = 2*60*HZ,
265 [IP_VS_TCP_S_TIME_WAIT] = 2*60*HZ,
266 [IP_VS_TCP_S_CLOSE] = 10*HZ,
267 [IP_VS_TCP_S_CLOSE_WAIT] = 60*HZ,
268 [IP_VS_TCP_S_LAST_ACK] = 30*HZ,
269 [IP_VS_TCP_S_LISTEN] = 2*60*HZ,
270 [IP_VS_TCP_S_SYNACK] = 120*HZ,
271 [IP_VS_TCP_S_LAST] = 2*HZ,
274 static char * tcp_state_name_table[IP_VS_TCP_S_LAST+1] = {
275 [IP_VS_TCP_S_NONE] = "NONE",
276 [IP_VS_TCP_S_ESTABLISHED] = "ESTABLISHED",
277 [IP_VS_TCP_S_SYN_SENT] = "SYN_SENT",
278 [IP_VS_TCP_S_SYN_RECV] = "SYN_RECV",
279 [IP_VS_TCP_S_FIN_WAIT] = "FIN_WAIT",
280 [IP_VS_TCP_S_TIME_WAIT] = "TIME_WAIT",
281 [IP_VS_TCP_S_CLOSE] = "CLOSE",
282 [IP_VS_TCP_S_CLOSE_WAIT] = "CLOSE_WAIT",
283 [IP_VS_TCP_S_LAST_ACK] = "LAST_ACK",
284 [IP_VS_TCP_S_LISTEN] = "LISTEN",
285 [IP_VS_TCP_S_SYNACK] = "SYNACK",
286 [IP_VS_TCP_S_LAST] = "BUG!",
289 #define sNO IP_VS_TCP_S_NONE
290 #define sES IP_VS_TCP_S_ESTABLISHED
291 #define sSS IP_VS_TCP_S_SYN_SENT
292 #define sSR IP_VS_TCP_S_SYN_RECV
293 #define sFW IP_VS_TCP_S_FIN_WAIT
294 #define sTW IP_VS_TCP_S_TIME_WAIT
295 #define sCL IP_VS_TCP_S_CLOSE
296 #define sCW IP_VS_TCP_S_CLOSE_WAIT
297 #define sLA IP_VS_TCP_S_LAST_ACK
298 #define sLI IP_VS_TCP_S_LISTEN
299 #define sSA IP_VS_TCP_S_SYNACK
301 struct tcp_states_t {
302 int next_state[IP_VS_TCP_S_LAST];
305 static const char * tcp_state_name(int state)
307 if (state >= IP_VS_TCP_S_LAST)
308 return "ERR!";
309 return tcp_state_name_table[state] ? tcp_state_name_table[state] : "?";
312 static struct tcp_states_t tcp_states [] = {
313 /* INPUT */
314 /* sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
315 /*syn*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSR }},
316 /*fin*/ {{sCL, sCW, sSS, sTW, sTW, sTW, sCL, sCW, sLA, sLI, sTW }},
317 /*ack*/ {{sCL, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
318 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sSR }},
320 /* OUTPUT */
321 /* sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
322 /*syn*/ {{sSS, sES, sSS, sSR, sSS, sSS, sSS, sSS, sSS, sLI, sSR }},
323 /*fin*/ {{sTW, sFW, sSS, sTW, sFW, sTW, sCL, sTW, sLA, sLI, sTW }},
324 /*ack*/ {{sES, sES, sSS, sES, sFW, sTW, sCL, sCW, sLA, sES, sES }},
325 /*rst*/ {{sCL, sCL, sSS, sCL, sCL, sTW, sCL, sCL, sCL, sCL, sCL }},
327 /* INPUT-ONLY */
328 /* sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
329 /*syn*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSR }},
330 /*fin*/ {{sCL, sFW, sSS, sTW, sFW, sTW, sCL, sCW, sLA, sLI, sTW }},
331 /*ack*/ {{sCL, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
332 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
335 static struct tcp_states_t tcp_states_dos [] = {
336 /* INPUT */
337 /* sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
338 /*syn*/ {{sSR, sES, sES, sSR, sSR, sSR, sSR, sSR, sSR, sSR, sSA }},
339 /*fin*/ {{sCL, sCW, sSS, sTW, sTW, sTW, sCL, sCW, sLA, sLI, sSA }},
340 /*ack*/ {{sCL, sES, sSS, sSR, sFW, sTW, sCL, sCW, sCL, sLI, sSA }},
341 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
343 /* OUTPUT */
344 /* sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
345 /*syn*/ {{sSS, sES, sSS, sSA, sSS, sSS, sSS, sSS, sSS, sLI, sSA }},
346 /*fin*/ {{sTW, sFW, sSS, sTW, sFW, sTW, sCL, sTW, sLA, sLI, sTW }},
347 /*ack*/ {{sES, sES, sSS, sES, sFW, sTW, sCL, sCW, sLA, sES, sES }},
348 /*rst*/ {{sCL, sCL, sSS, sCL, sCL, sTW, sCL, sCL, sCL, sCL, sCL }},
350 /* INPUT-ONLY */
351 /* sNO, sES, sSS, sSR, sFW, sTW, sCL, sCW, sLA, sLI, sSA */
352 /*syn*/ {{sSA, sES, sES, sSR, sSA, sSA, sSA, sSA, sSA, sSA, sSA }},
353 /*fin*/ {{sCL, sFW, sSS, sTW, sFW, sTW, sCL, sCW, sLA, sLI, sTW }},
354 /*ack*/ {{sCL, sES, sSS, sES, sFW, sTW, sCL, sCW, sCL, sLI, sES }},
355 /*rst*/ {{sCL, sCL, sCL, sSR, sCL, sCL, sCL, sCL, sLA, sLI, sCL }},
358 static struct tcp_states_t *tcp_state_table = tcp_states;
361 static void tcp_timeout_change(struct ip_vs_protocol *pp, int flags)
363 int on = (flags & 1); /* secure_tcp */
366 ** FIXME: change secure_tcp to independent sysctl var
367 ** or make it per-service or per-app because it is valid
368 ** for most if not for all of the applications. Something
369 ** like "capabilities" (flags) for each object.
371 tcp_state_table = (on? tcp_states_dos : tcp_states);
374 static int
375 tcp_set_state_timeout(struct ip_vs_protocol *pp, char *sname, int to)
377 return ip_vs_set_state_timeout(pp->timeout_table, IP_VS_TCP_S_LAST,
378 tcp_state_name_table, sname, to);
381 static inline int tcp_state_idx(struct tcphdr *th)
383 if (th->rst)
384 return 3;
385 if (th->syn)
386 return 0;
387 if (th->fin)
388 return 1;
389 if (th->ack)
390 return 2;
391 return -1;
394 static inline void
395 set_tcp_state(struct ip_vs_protocol *pp, struct ip_vs_conn *cp,
396 int direction, struct tcphdr *th)
398 int state_idx;
399 int new_state = IP_VS_TCP_S_CLOSE;
400 int state_off = tcp_state_off[direction];
403 * Update state offset to INPUT_ONLY if necessary
404 * or delete NO_OUTPUT flag if output packet detected
406 if (cp->flags & IP_VS_CONN_F_NOOUTPUT) {
407 if (state_off == TCP_DIR_OUTPUT)
408 cp->flags &= ~IP_VS_CONN_F_NOOUTPUT;
409 else
410 state_off = TCP_DIR_INPUT_ONLY;
413 if ((state_idx = tcp_state_idx(th)) < 0) {
414 IP_VS_DBG(8, "tcp_state_idx=%d!!!\n", state_idx);
415 goto tcp_state_out;
418 new_state = tcp_state_table[state_off+state_idx].next_state[cp->state];
420 tcp_state_out:
421 if (new_state != cp->state) {
422 struct ip_vs_dest *dest = cp->dest;
424 IP_VS_DBG(8, "%s %s [%c%c%c%c] %u.%u.%u.%u:%d->"
425 "%u.%u.%u.%u:%d state: %s->%s conn->refcnt:%d\n",
426 pp->name,
427 (state_off==TCP_DIR_OUTPUT)?"output ":"input ",
428 th->syn? 'S' : '.',
429 th->fin? 'F' : '.',
430 th->ack? 'A' : '.',
431 th->rst? 'R' : '.',
432 NIPQUAD(cp->daddr), ntohs(cp->dport),
433 NIPQUAD(cp->caddr), ntohs(cp->cport),
434 tcp_state_name(cp->state),
435 tcp_state_name(new_state),
436 atomic_read(&cp->refcnt));
437 if (dest) {
438 if (!(cp->flags & IP_VS_CONN_F_INACTIVE) &&
439 (new_state != IP_VS_TCP_S_ESTABLISHED)) {
440 atomic_dec(&dest->activeconns);
441 atomic_inc(&dest->inactconns);
442 cp->flags |= IP_VS_CONN_F_INACTIVE;
443 } else if ((cp->flags & IP_VS_CONN_F_INACTIVE) &&
444 (new_state == IP_VS_TCP_S_ESTABLISHED)) {
445 atomic_inc(&dest->activeconns);
446 atomic_dec(&dest->inactconns);
447 cp->flags &= ~IP_VS_CONN_F_INACTIVE;
452 cp->timeout = pp->timeout_table[cp->state = new_state];
457 * Handle state transitions
459 static int
460 tcp_state_transition(struct ip_vs_conn *cp, int direction,
461 const struct sk_buff *skb,
462 struct ip_vs_protocol *pp)
464 struct tcphdr _tcph, *th;
466 th = skb_header_pointer(skb, ip_hdrlen(skb), sizeof(_tcph), &_tcph);
467 if (th == NULL)
468 return 0;
470 spin_lock(&cp->lock);
471 set_tcp_state(pp, cp, direction, th);
472 spin_unlock(&cp->lock);
474 return 1;
479 * Hash table for TCP application incarnations
481 #define TCP_APP_TAB_BITS 4
482 #define TCP_APP_TAB_SIZE (1 << TCP_APP_TAB_BITS)
483 #define TCP_APP_TAB_MASK (TCP_APP_TAB_SIZE - 1)
485 static struct list_head tcp_apps[TCP_APP_TAB_SIZE];
486 static DEFINE_SPINLOCK(tcp_app_lock);
488 static inline __u16 tcp_app_hashkey(__be16 port)
490 return (((__force u16)port >> TCP_APP_TAB_BITS) ^ (__force u16)port)
491 & TCP_APP_TAB_MASK;
495 static int tcp_register_app(struct ip_vs_app *inc)
497 struct ip_vs_app *i;
498 __u16 hash;
499 __be16 port = inc->port;
500 int ret = 0;
502 hash = tcp_app_hashkey(port);
504 spin_lock_bh(&tcp_app_lock);
505 list_for_each_entry(i, &tcp_apps[hash], p_list) {
506 if (i->port == port) {
507 ret = -EEXIST;
508 goto out;
511 list_add(&inc->p_list, &tcp_apps[hash]);
512 atomic_inc(&ip_vs_protocol_tcp.appcnt);
514 out:
515 spin_unlock_bh(&tcp_app_lock);
516 return ret;
520 static void
521 tcp_unregister_app(struct ip_vs_app *inc)
523 spin_lock_bh(&tcp_app_lock);
524 atomic_dec(&ip_vs_protocol_tcp.appcnt);
525 list_del(&inc->p_list);
526 spin_unlock_bh(&tcp_app_lock);
530 static int
531 tcp_app_conn_bind(struct ip_vs_conn *cp)
533 int hash;
534 struct ip_vs_app *inc;
535 int result = 0;
537 /* Default binding: bind app only for NAT */
538 if (IP_VS_FWD_METHOD(cp) != IP_VS_CONN_F_MASQ)
539 return 0;
541 /* Lookup application incarnations and bind the right one */
542 hash = tcp_app_hashkey(cp->vport);
544 spin_lock(&tcp_app_lock);
545 list_for_each_entry(inc, &tcp_apps[hash], p_list) {
546 if (inc->port == cp->vport) {
547 if (unlikely(!ip_vs_app_inc_get(inc)))
548 break;
549 spin_unlock(&tcp_app_lock);
551 IP_VS_DBG(9, "%s: Binding conn %u.%u.%u.%u:%u->"
552 "%u.%u.%u.%u:%u to app %s on port %u\n",
553 __FUNCTION__,
554 NIPQUAD(cp->caddr), ntohs(cp->cport),
555 NIPQUAD(cp->vaddr), ntohs(cp->vport),
556 inc->name, ntohs(inc->port));
557 cp->app = inc;
558 if (inc->init_conn)
559 result = inc->init_conn(inc, cp);
560 goto out;
563 spin_unlock(&tcp_app_lock);
565 out:
566 return result;
571 * Set LISTEN timeout. (ip_vs_conn_put will setup timer)
573 void ip_vs_tcp_conn_listen(struct ip_vs_conn *cp)
575 spin_lock(&cp->lock);
576 cp->state = IP_VS_TCP_S_LISTEN;
577 cp->timeout = ip_vs_protocol_tcp.timeout_table[IP_VS_TCP_S_LISTEN];
578 spin_unlock(&cp->lock);
582 static void ip_vs_tcp_init(struct ip_vs_protocol *pp)
584 IP_VS_INIT_HASH_TABLE(tcp_apps);
585 pp->timeout_table = tcp_timeouts;
589 static void ip_vs_tcp_exit(struct ip_vs_protocol *pp)
594 struct ip_vs_protocol ip_vs_protocol_tcp = {
595 .name = "TCP",
596 .protocol = IPPROTO_TCP,
597 .dont_defrag = 0,
598 .appcnt = ATOMIC_INIT(0),
599 .init = ip_vs_tcp_init,
600 .exit = ip_vs_tcp_exit,
601 .register_app = tcp_register_app,
602 .unregister_app = tcp_unregister_app,
603 .conn_schedule = tcp_conn_schedule,
604 .conn_in_get = tcp_conn_in_get,
605 .conn_out_get = tcp_conn_out_get,
606 .snat_handler = tcp_snat_handler,
607 .dnat_handler = tcp_dnat_handler,
608 .csum_check = tcp_csum_check,
609 .state_name = tcp_state_name,
610 .state_transition = tcp_state_transition,
611 .app_conn_bind = tcp_app_conn_bind,
612 .debug_packet = ip_vs_tcpudp_debug_packet,
613 .timeout_change = tcp_timeout_change,
614 .set_state_timeout = tcp_set_state_timeout,