2 * Connection tracking protocol helper module for SCTP.
4 * SCTP is defined in RFC 2960. References to various sections in this code
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
13 * Added support for proc manipulation of timeouts.
16 #include <linux/types.h>
17 #include <linux/sched.h>
18 #include <linux/timer.h>
19 #include <linux/netfilter.h>
20 #include <linux/module.h>
23 #include <linux/sctp.h>
24 #include <linux/string.h>
25 #include <linux/seq_file.h>
27 #include <linux/netfilter_ipv4/ip_conntrack.h>
28 #include <linux/netfilter_ipv4/ip_conntrack_protocol.h>
31 #define DEBUGP(format, ...) printk(format, ## __VA_ARGS__)
33 #define DEBUGP(format, args...)
36 /* Protects conntrack->proto.sctp */
37 static DEFINE_RWLOCK(sctp_lock);
39 /* FIXME: Examine ipfilter's timeouts and conntrack transitions more
40 closely. They're more complex. --RR
42 And so for me for SCTP :D -Kiran */
44 static const char *sctp_conntrack_names[] = {
56 #define MINS * 60 SECS
57 #define HOURS * 60 MINS
58 #define DAYS * 24 HOURS
60 static unsigned long ip_ct_sctp_timeout_closed = 10 SECS;
61 static unsigned long ip_ct_sctp_timeout_cookie_wait = 3 SECS;
62 static unsigned long ip_ct_sctp_timeout_cookie_echoed = 3 SECS;
63 static unsigned long ip_ct_sctp_timeout_established = 5 DAYS;
64 static unsigned long ip_ct_sctp_timeout_shutdown_sent = 300 SECS / 1000;
65 static unsigned long ip_ct_sctp_timeout_shutdown_recd = 300 SECS / 1000;
66 static unsigned long ip_ct_sctp_timeout_shutdown_ack_sent = 3 SECS;
68 static unsigned long * sctp_timeouts[]
69 = { NULL, /* SCTP_CONNTRACK_NONE */
70 &ip_ct_sctp_timeout_closed, /* SCTP_CONNTRACK_CLOSED */
71 &ip_ct_sctp_timeout_cookie_wait, /* SCTP_CONNTRACK_COOKIE_WAIT */
72 &ip_ct_sctp_timeout_cookie_echoed, /* SCTP_CONNTRACK_COOKIE_ECHOED */
73 &ip_ct_sctp_timeout_established, /* SCTP_CONNTRACK_ESTABLISHED */
74 &ip_ct_sctp_timeout_shutdown_sent, /* SCTP_CONNTRACK_SHUTDOWN_SENT */
75 &ip_ct_sctp_timeout_shutdown_recd, /* SCTP_CONNTRACK_SHUTDOWN_RECD */
76 &ip_ct_sctp_timeout_shutdown_ack_sent /* SCTP_CONNTRACK_SHUTDOWN_ACK_SENT */
79 #define sNO SCTP_CONNTRACK_NONE
80 #define sCL SCTP_CONNTRACK_CLOSED
81 #define sCW SCTP_CONNTRACK_COOKIE_WAIT
82 #define sCE SCTP_CONNTRACK_COOKIE_ECHOED
83 #define sES SCTP_CONNTRACK_ESTABLISHED
84 #define sSS SCTP_CONNTRACK_SHUTDOWN_SENT
85 #define sSR SCTP_CONNTRACK_SHUTDOWN_RECD
86 #define sSA SCTP_CONNTRACK_SHUTDOWN_ACK_SENT
87 #define sIV SCTP_CONNTRACK_MAX
90 These are the descriptions of the states:
92 NOTE: These state names are tantalizingly similar to the states of an
93 SCTP endpoint. But the interpretation of the states is a little different,
94 considering that these are the states of the connection and not of an end
95 point. Please note the subtleties. -Kiran
97 NONE - Nothing so far.
98 COOKIE WAIT - We have seen an INIT chunk in the original direction, or also
99 an INIT_ACK chunk in the reply direction.
100 COOKIE ECHOED - We have seen a COOKIE_ECHO chunk in the original direction.
101 ESTABLISHED - We have seen a COOKIE_ACK in the reply direction.
102 SHUTDOWN_SENT - We have seen a SHUTDOWN chunk in the original direction.
103 SHUTDOWN_RECD - We have seen a SHUTDOWN chunk in the reply directoin.
104 SHUTDOWN_ACK_SENT - We have seen a SHUTDOWN_ACK chunk in the direction opposite
105 to that of the SHUTDOWN chunk.
106 CLOSED - We have seen a SHUTDOWN_COMPLETE chunk in the direction of
107 the SHUTDOWN chunk. Connection is closed.
111 - I have assumed that the first INIT is in the original direction.
112 This messes things when an INIT comes in the reply direction in CLOSED
114 - Check the error type in the reply dir before transitioning from
115 cookie echoed to closed.
116 - Sec 5.2.4 of RFC 2960
117 - Multi Homing support.
120 /* SCTP conntrack state transitions */
121 static enum sctp_conntrack sctp_conntracks[2][9][SCTP_CONNTRACK_MAX] = {
124 /* sNO, sCL, sCW, sCE, sES, sSS, sSR, sSA */
125 /* init */ {sCW, sCW, sCW, sCE, sES, sSS, sSR, sSA},
126 /* init_ack */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA},
127 /* abort */ {sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL},
128 /* shutdown */ {sCL, sCL, sCW, sCE, sSS, sSS, sSR, sSA},
129 /* shutdown_ack */ {sSA, sCL, sCW, sCE, sES, sSA, sSA, sSA},
130 /* error */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA},/* Cant have Stale cookie*/
131 /* cookie_echo */ {sCL, sCL, sCE, sCE, sES, sSS, sSR, sSA},/* 5.2.4 - Big TODO */
132 /* cookie_ack */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA},/* Cant come in orig dir */
133 /* shutdown_comp*/ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sCL}
137 /* sNO, sCL, sCW, sCE, sES, sSS, sSR, sSA */
138 /* init */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA},/* INIT in sCL Big TODO */
139 /* init_ack */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA},
140 /* abort */ {sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL},
141 /* shutdown */ {sIV, sCL, sCW, sCE, sSR, sSS, sSR, sSA},
142 /* shutdown_ack */ {sIV, sCL, sCW, sCE, sES, sSA, sSA, sSA},
143 /* error */ {sIV, sCL, sCW, sCL, sES, sSS, sSR, sSA},
144 /* cookie_echo */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA},/* Cant come in reply dir */
145 /* cookie_ack */ {sIV, sCL, sCW, sES, sES, sSS, sSR, sSA},
146 /* shutdown_comp*/ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sCL}
150 static int sctp_pkt_to_tuple(const struct sk_buff *skb,
151 unsigned int dataoff,
152 struct ip_conntrack_tuple *tuple)
154 sctp_sctphdr_t _hdr, *hp;
156 DEBUGP(__FUNCTION__);
159 /* Actually only need first 8 bytes. */
160 hp = skb_header_pointer(skb, dataoff, 8, &_hdr);
164 tuple->src.u.sctp.port = hp->source;
165 tuple->dst.u.sctp.port = hp->dest;
169 static int sctp_invert_tuple(struct ip_conntrack_tuple *tuple,
170 const struct ip_conntrack_tuple *orig)
172 DEBUGP(__FUNCTION__);
175 tuple->src.u.sctp.port = orig->dst.u.sctp.port;
176 tuple->dst.u.sctp.port = orig->src.u.sctp.port;
180 /* Print out the per-protocol part of the tuple. */
181 static int sctp_print_tuple(struct seq_file *s,
182 const struct ip_conntrack_tuple *tuple)
184 DEBUGP(__FUNCTION__);
187 return seq_printf(s, "sport=%hu dport=%hu ",
188 ntohs(tuple->src.u.sctp.port),
189 ntohs(tuple->dst.u.sctp.port));
192 /* Print out the private part of the conntrack. */
193 static int sctp_print_conntrack(struct seq_file *s,
194 const struct ip_conntrack *conntrack)
196 enum sctp_conntrack state;
198 DEBUGP(__FUNCTION__);
201 read_lock_bh(&sctp_lock);
202 state = conntrack->proto.sctp.state;
203 read_unlock_bh(&sctp_lock);
205 return seq_printf(s, "%s ", sctp_conntrack_names[state]);
208 #define for_each_sctp_chunk(skb, sch, _sch, offset, count) \
209 for (offset = skb->nh.iph->ihl * 4 + sizeof(sctp_sctphdr_t), count = 0; \
210 offset < skb->len && \
211 (sch = skb_header_pointer(skb, offset, sizeof(_sch), &_sch)); \
212 offset += (htons(sch->length) + 3) & ~3, count++)
214 /* Some validity checks to make sure the chunks are fine */
215 static int do_basic_checks(struct ip_conntrack *conntrack,
216 const struct sk_buff *skb,
219 u_int32_t offset, count;
220 sctp_chunkhdr_t _sch, *sch;
223 DEBUGP(__FUNCTION__);
228 for_each_sctp_chunk (skb, sch, _sch, offset, count) {
229 DEBUGP("Chunk Num: %d Type: %d\n", count, sch->type);
231 if (sch->type == SCTP_CID_INIT
232 || sch->type == SCTP_CID_INIT_ACK
233 || sch->type == SCTP_CID_SHUTDOWN_COMPLETE) {
237 /* Cookie Ack/Echo chunks not the first OR
238 Init / Init Ack / Shutdown compl chunks not the only chunks */
239 if ((sch->type == SCTP_CID_COOKIE_ACK
240 || sch->type == SCTP_CID_COOKIE_ECHO
243 DEBUGP("Basic checks failed\n");
248 set_bit(sch->type, (void *)map);
252 DEBUGP("Basic checks passed\n");
256 static int new_state(enum ip_conntrack_dir dir,
257 enum sctp_conntrack cur_state,
262 DEBUGP(__FUNCTION__);
265 DEBUGP("Chunk type: %d\n", chunk_type);
267 switch (chunk_type) {
269 DEBUGP("SCTP_CID_INIT\n");
271 case SCTP_CID_INIT_ACK:
272 DEBUGP("SCTP_CID_INIT_ACK\n");
275 DEBUGP("SCTP_CID_ABORT\n");
277 case SCTP_CID_SHUTDOWN:
278 DEBUGP("SCTP_CID_SHUTDOWN\n");
280 case SCTP_CID_SHUTDOWN_ACK:
281 DEBUGP("SCTP_CID_SHUTDOWN_ACK\n");
284 DEBUGP("SCTP_CID_ERROR\n");
286 case SCTP_CID_COOKIE_ECHO:
287 DEBUGP("SCTP_CID_COOKIE_ECHO\n");
289 case SCTP_CID_COOKIE_ACK:
290 DEBUGP("SCTP_CID_COOKIE_ACK\n");
292 case SCTP_CID_SHUTDOWN_COMPLETE:
293 DEBUGP("SCTP_CID_SHUTDOWN_COMPLETE\n");
296 /* Other chunks like DATA, SACK, HEARTBEAT and
297 its ACK do not cause a change in state */
298 DEBUGP("Unknown chunk type, Will stay in %s\n",
299 sctp_conntrack_names[cur_state]);
303 DEBUGP("dir: %d cur_state: %s chunk_type: %d new_state: %s\n",
304 dir, sctp_conntrack_names[cur_state], chunk_type,
305 sctp_conntrack_names[sctp_conntracks[dir][i][cur_state]]);
307 return sctp_conntracks[dir][i][cur_state];
310 /* Returns verdict for packet, or -1 for invalid. */
311 static int sctp_packet(struct ip_conntrack *conntrack,
312 const struct sk_buff *skb,
313 enum ip_conntrack_info ctinfo)
315 enum sctp_conntrack newconntrack, oldsctpstate;
316 struct iphdr *iph = skb->nh.iph;
317 sctp_sctphdr_t _sctph, *sh;
318 sctp_chunkhdr_t _sch, *sch;
319 u_int32_t offset, count;
320 char map[256 / sizeof (char)] = {0};
322 DEBUGP(__FUNCTION__);
325 sh = skb_header_pointer(skb, iph->ihl * 4, sizeof(_sctph), &_sctph);
329 if (do_basic_checks(conntrack, skb, map) != 0)
332 /* Check the verification tag (Sec 8.5) */
333 if (!test_bit(SCTP_CID_INIT, (void *)map)
334 && !test_bit(SCTP_CID_SHUTDOWN_COMPLETE, (void *)map)
335 && !test_bit(SCTP_CID_COOKIE_ECHO, (void *)map)
336 && !test_bit(SCTP_CID_ABORT, (void *)map)
337 && !test_bit(SCTP_CID_SHUTDOWN_ACK, (void *)map)
338 && (sh->vtag != conntrack->proto.sctp.vtag[CTINFO2DIR(ctinfo)])) {
339 DEBUGP("Verification tag check failed\n");
343 oldsctpstate = newconntrack = SCTP_CONNTRACK_MAX;
344 for_each_sctp_chunk (skb, sch, _sch, offset, count) {
345 write_lock_bh(&sctp_lock);
347 /* Special cases of Verification tag check (Sec 8.5.1) */
348 if (sch->type == SCTP_CID_INIT) {
351 write_unlock_bh(&sctp_lock);
354 } else if (sch->type == SCTP_CID_ABORT) {
356 if (!(sh->vtag == conntrack->proto.sctp.vtag[CTINFO2DIR(ctinfo)])
357 && !(sh->vtag == conntrack->proto.sctp.vtag
358 [1 - CTINFO2DIR(ctinfo)])) {
359 write_unlock_bh(&sctp_lock);
362 } else if (sch->type == SCTP_CID_SHUTDOWN_COMPLETE) {
364 if (!(sh->vtag == conntrack->proto.sctp.vtag[CTINFO2DIR(ctinfo)])
365 && !(sh->vtag == conntrack->proto.sctp.vtag
366 [1 - CTINFO2DIR(ctinfo)]
367 && (sch->flags & 1))) {
368 write_unlock_bh(&sctp_lock);
371 } else if (sch->type == SCTP_CID_COOKIE_ECHO) {
373 if (!(sh->vtag == conntrack->proto.sctp.vtag[CTINFO2DIR(ctinfo)])) {
374 write_unlock_bh(&sctp_lock);
379 oldsctpstate = conntrack->proto.sctp.state;
380 newconntrack = new_state(CTINFO2DIR(ctinfo), oldsctpstate, sch->type);
383 if (newconntrack == SCTP_CONNTRACK_MAX) {
384 DEBUGP("ip_conntrack_sctp: Invalid dir=%i ctype=%u conntrack=%u\n",
385 CTINFO2DIR(ctinfo), sch->type, oldsctpstate);
386 write_unlock_bh(&sctp_lock);
390 /* If it is an INIT or an INIT ACK note down the vtag */
391 if (sch->type == SCTP_CID_INIT
392 || sch->type == SCTP_CID_INIT_ACK) {
393 sctp_inithdr_t _inithdr, *ih;
395 ih = skb_header_pointer(skb, offset + sizeof(sctp_chunkhdr_t),
396 sizeof(_inithdr), &_inithdr);
398 write_unlock_bh(&sctp_lock);
401 DEBUGP("Setting vtag %x for dir %d\n",
402 ih->init_tag, !CTINFO2DIR(ctinfo));
403 conntrack->proto.sctp.vtag[!CTINFO2DIR(ctinfo)] = ih->init_tag;
406 conntrack->proto.sctp.state = newconntrack;
407 if (oldsctpstate != newconntrack)
408 ip_conntrack_event_cache(IPCT_PROTOINFO, skb);
409 write_unlock_bh(&sctp_lock);
412 ip_ct_refresh_acct(conntrack, ctinfo, skb, *sctp_timeouts[newconntrack]);
414 if (oldsctpstate == SCTP_CONNTRACK_COOKIE_ECHOED
415 && CTINFO2DIR(ctinfo) == IP_CT_DIR_REPLY
416 && newconntrack == SCTP_CONNTRACK_ESTABLISHED) {
417 DEBUGP("Setting assured bit\n");
418 set_bit(IPS_ASSURED_BIT, &conntrack->status);
419 ip_conntrack_event_cache(IPCT_STATUS, skb);
425 /* Called when a new connection for this protocol found. */
426 static int sctp_new(struct ip_conntrack *conntrack,
427 const struct sk_buff *skb)
429 enum sctp_conntrack newconntrack;
430 struct iphdr *iph = skb->nh.iph;
431 sctp_sctphdr_t _sctph, *sh;
432 sctp_chunkhdr_t _sch, *sch;
433 u_int32_t offset, count;
434 char map[256 / sizeof (char)] = {0};
436 DEBUGP(__FUNCTION__);
439 sh = skb_header_pointer(skb, iph->ihl * 4, sizeof(_sctph), &_sctph);
443 if (do_basic_checks(conntrack, skb, map) != 0)
446 /* If an OOTB packet has any of these chunks discard (Sec 8.4) */
447 if ((test_bit (SCTP_CID_ABORT, (void *)map))
448 || (test_bit (SCTP_CID_SHUTDOWN_COMPLETE, (void *)map))
449 || (test_bit (SCTP_CID_COOKIE_ACK, (void *)map))) {
453 newconntrack = SCTP_CONNTRACK_MAX;
454 for_each_sctp_chunk (skb, sch, _sch, offset, count) {
455 /* Don't need lock here: this conntrack not in circulation yet */
456 newconntrack = new_state (IP_CT_DIR_ORIGINAL,
457 SCTP_CONNTRACK_NONE, sch->type);
459 /* Invalid: delete conntrack */
460 if (newconntrack == SCTP_CONNTRACK_MAX) {
461 DEBUGP("ip_conntrack_sctp: invalid new deleting.\n");
465 /* Copy the vtag into the state info */
466 if (sch->type == SCTP_CID_INIT) {
468 sctp_inithdr_t _inithdr, *ih;
470 ih = skb_header_pointer(skb, offset + sizeof(sctp_chunkhdr_t),
471 sizeof(_inithdr), &_inithdr);
475 DEBUGP("Setting vtag %x for new conn\n",
478 conntrack->proto.sctp.vtag[IP_CT_DIR_REPLY] =
485 /* If it is a shutdown ack OOTB packet, we expect a return
486 shutdown complete, otherwise an ABORT Sec 8.4 (5) and (8) */
488 DEBUGP("Setting vtag %x for new conn OOTB\n",
490 conntrack->proto.sctp.vtag[IP_CT_DIR_REPLY] = sh->vtag;
493 conntrack->proto.sctp.state = newconntrack;
499 static struct ip_conntrack_protocol ip_conntrack_protocol_sctp = {
500 .proto = IPPROTO_SCTP,
502 .pkt_to_tuple = sctp_pkt_to_tuple,
503 .invert_tuple = sctp_invert_tuple,
504 .print_tuple = sctp_print_tuple,
505 .print_conntrack = sctp_print_conntrack,
506 .packet = sctp_packet,
510 #if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \
511 defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE)
512 .tuple_to_nfattr = ip_ct_port_tuple_to_nfattr,
513 .nfattr_to_tuple = ip_ct_port_nfattr_to_tuple,
518 static ctl_table ip_ct_sysctl_table[] = {
520 .ctl_name = NET_IPV4_NF_CONNTRACK_SCTP_TIMEOUT_CLOSED,
521 .procname = "ip_conntrack_sctp_timeout_closed",
522 .data = &ip_ct_sctp_timeout_closed,
523 .maxlen = sizeof(unsigned int),
525 .proc_handler = &proc_dointvec_jiffies,
528 .ctl_name = NET_IPV4_NF_CONNTRACK_SCTP_TIMEOUT_COOKIE_WAIT,
529 .procname = "ip_conntrack_sctp_timeout_cookie_wait",
530 .data = &ip_ct_sctp_timeout_cookie_wait,
531 .maxlen = sizeof(unsigned int),
533 .proc_handler = &proc_dointvec_jiffies,
536 .ctl_name = NET_IPV4_NF_CONNTRACK_SCTP_TIMEOUT_COOKIE_ECHOED,
537 .procname = "ip_conntrack_sctp_timeout_cookie_echoed",
538 .data = &ip_ct_sctp_timeout_cookie_echoed,
539 .maxlen = sizeof(unsigned int),
541 .proc_handler = &proc_dointvec_jiffies,
544 .ctl_name = NET_IPV4_NF_CONNTRACK_SCTP_TIMEOUT_ESTABLISHED,
545 .procname = "ip_conntrack_sctp_timeout_established",
546 .data = &ip_ct_sctp_timeout_established,
547 .maxlen = sizeof(unsigned int),
549 .proc_handler = &proc_dointvec_jiffies,
552 .ctl_name = NET_IPV4_NF_CONNTRACK_SCTP_TIMEOUT_SHUTDOWN_SENT,
553 .procname = "ip_conntrack_sctp_timeout_shutdown_sent",
554 .data = &ip_ct_sctp_timeout_shutdown_sent,
555 .maxlen = sizeof(unsigned int),
557 .proc_handler = &proc_dointvec_jiffies,
560 .ctl_name = NET_IPV4_NF_CONNTRACK_SCTP_TIMEOUT_SHUTDOWN_RECD,
561 .procname = "ip_conntrack_sctp_timeout_shutdown_recd",
562 .data = &ip_ct_sctp_timeout_shutdown_recd,
563 .maxlen = sizeof(unsigned int),
565 .proc_handler = &proc_dointvec_jiffies,
568 .ctl_name = NET_IPV4_NF_CONNTRACK_SCTP_TIMEOUT_SHUTDOWN_ACK_SENT,
569 .procname = "ip_conntrack_sctp_timeout_shutdown_ack_sent",
570 .data = &ip_ct_sctp_timeout_shutdown_ack_sent,
571 .maxlen = sizeof(unsigned int),
573 .proc_handler = &proc_dointvec_jiffies,
578 static ctl_table ip_ct_netfilter_table[] = {
580 .ctl_name = NET_IPV4_NETFILTER,
581 .procname = "netfilter",
583 .child = ip_ct_sysctl_table,
588 static ctl_table ip_ct_ipv4_table[] = {
590 .ctl_name = NET_IPV4,
593 .child = ip_ct_netfilter_table,
598 static ctl_table ip_ct_net_table[] = {
603 .child = ip_ct_ipv4_table,
608 static struct ctl_table_header *ip_ct_sysctl_header;
611 static int __init init(void)
615 ret = ip_conntrack_protocol_register(&ip_conntrack_protocol_sctp);
617 printk("ip_conntrack_proto_sctp: protocol register failed\n");
622 ip_ct_sysctl_header = register_sysctl_table(ip_ct_net_table, 0);
623 if (ip_ct_sysctl_header == NULL) {
625 printk("ip_conntrack_proto_sctp: can't register to sysctl.\n");
634 ip_conntrack_protocol_unregister(&ip_conntrack_protocol_sctp);
637 DEBUGP("SCTP conntrack module loading %s\n",
638 ret ? "failed": "succeeded");
642 static void __exit fini(void)
644 ip_conntrack_protocol_unregister(&ip_conntrack_protocol_sctp);
646 unregister_sysctl_table(ip_ct_sysctl_header);
648 DEBUGP("SCTP conntrack module unloaded\n");
654 MODULE_LICENSE("GPL");
655 MODULE_AUTHOR("Kiran Kumar Immidi");
656 MODULE_DESCRIPTION("Netfilter connection tracking protocol helper for SCTP");