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.
12 #include <linux/types.h>
13 #include <linux/timer.h>
14 #include <linux/netfilter.h>
15 #include <linux/module.h>
18 #include <linux/sctp.h>
19 #include <linux/string.h>
20 #include <linux/seq_file.h>
21 #include <linux/spinlock.h>
22 #include <linux/interrupt.h>
24 #include <net/netfilter/nf_conntrack.h>
25 #include <net/netfilter/nf_conntrack_l4proto.h>
26 #include <net/netfilter/nf_conntrack_ecache.h>
28 /* Protects ct->proto.sctp */
29 static DEFINE_RWLOCK(sctp_lock);
31 /* FIXME: Examine ipfilter's timeouts and conntrack transitions more
32 closely. They're more complex. --RR
34 And so for me for SCTP :D -Kiran */
36 static const char *sctp_conntrack_names[] = {
48 #define MINS * 60 SECS
49 #define HOURS * 60 MINS
50 #define DAYS * 24 HOURS
52 static unsigned int sctp_timeouts[SCTP_CONNTRACK_MAX] __read_mostly = {
53 [SCTP_CONNTRACK_CLOSED] = 10 SECS,
54 [SCTP_CONNTRACK_COOKIE_WAIT] = 3 SECS,
55 [SCTP_CONNTRACK_COOKIE_ECHOED] = 3 SECS,
56 [SCTP_CONNTRACK_ESTABLISHED] = 5 DAYS,
57 [SCTP_CONNTRACK_SHUTDOWN_SENT] = 300 SECS / 1000,
58 [SCTP_CONNTRACK_SHUTDOWN_RECD] = 300 SECS / 1000,
59 [SCTP_CONNTRACK_SHUTDOWN_ACK_SENT] = 3 SECS,
62 #define sNO SCTP_CONNTRACK_NONE
63 #define sCL SCTP_CONNTRACK_CLOSED
64 #define sCW SCTP_CONNTRACK_COOKIE_WAIT
65 #define sCE SCTP_CONNTRACK_COOKIE_ECHOED
66 #define sES SCTP_CONNTRACK_ESTABLISHED
67 #define sSS SCTP_CONNTRACK_SHUTDOWN_SENT
68 #define sSR SCTP_CONNTRACK_SHUTDOWN_RECD
69 #define sSA SCTP_CONNTRACK_SHUTDOWN_ACK_SENT
70 #define sIV SCTP_CONNTRACK_MAX
73 These are the descriptions of the states:
75 NOTE: These state names are tantalizingly similar to the states of an
76 SCTP endpoint. But the interpretation of the states is a little different,
77 considering that these are the states of the connection and not of an end
78 point. Please note the subtleties. -Kiran
80 NONE - Nothing so far.
81 COOKIE WAIT - We have seen an INIT chunk in the original direction, or also
82 an INIT_ACK chunk in the reply direction.
83 COOKIE ECHOED - We have seen a COOKIE_ECHO chunk in the original direction.
84 ESTABLISHED - We have seen a COOKIE_ACK in the reply direction.
85 SHUTDOWN_SENT - We have seen a SHUTDOWN chunk in the original direction.
86 SHUTDOWN_RECD - We have seen a SHUTDOWN chunk in the reply directoin.
87 SHUTDOWN_ACK_SENT - We have seen a SHUTDOWN_ACK chunk in the direction opposite
88 to that of the SHUTDOWN chunk.
89 CLOSED - We have seen a SHUTDOWN_COMPLETE chunk in the direction of
90 the SHUTDOWN chunk. Connection is closed.
94 - I have assumed that the first INIT is in the original direction.
95 This messes things when an INIT comes in the reply direction in CLOSED
97 - Check the error type in the reply dir before transitioning from
98 cookie echoed to closed.
99 - Sec 5.2.4 of RFC 2960
100 - Multi Homing support.
103 /* SCTP conntrack state transitions */
104 static const u8 sctp_conntracks[2][9][SCTP_CONNTRACK_MAX] = {
107 /* sNO, sCL, sCW, sCE, sES, sSS, sSR, sSA */
108 /* init */ {sCW, sCW, sCW, sCE, sES, sSS, sSR, sSA},
109 /* init_ack */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA},
110 /* abort */ {sCL, sCL, sCL, sCL, sCL, sCL, sCL, sCL},
111 /* shutdown */ {sCL, sCL, sCW, sCE, sSS, sSS, sSR, sSA},
112 /* shutdown_ack */ {sSA, sCL, sCW, sCE, sES, sSA, sSA, sSA},
113 /* error */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA},/* Cant have Stale cookie*/
114 /* cookie_echo */ {sCL, sCL, sCE, sCE, sES, sSS, sSR, sSA},/* 5.2.4 - Big TODO */
115 /* cookie_ack */ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sSA},/* Cant come in orig dir */
116 /* shutdown_comp*/ {sCL, sCL, sCW, sCE, sES, sSS, sSR, sCL}
120 /* sNO, sCL, sCW, sCE, sES, sSS, sSR, sSA */
121 /* init */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA},/* INIT in sCL Big TODO */
122 /* init_ack */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA},
123 /* abort */ {sIV, sCL, sCL, sCL, sCL, sCL, sCL, sCL},
124 /* shutdown */ {sIV, sCL, sCW, sCE, sSR, sSS, sSR, sSA},
125 /* shutdown_ack */ {sIV, sCL, sCW, sCE, sES, sSA, sSA, sSA},
126 /* error */ {sIV, sCL, sCW, sCL, sES, sSS, sSR, sSA},
127 /* cookie_echo */ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sSA},/* Cant come in reply dir */
128 /* cookie_ack */ {sIV, sCL, sCW, sES, sES, sSS, sSR, sSA},
129 /* shutdown_comp*/ {sIV, sCL, sCW, sCE, sES, sSS, sSR, sCL}
133 static int sctp_pkt_to_tuple(const struct sk_buff *skb,
134 unsigned int dataoff,
135 struct nf_conntrack_tuple *tuple)
137 sctp_sctphdr_t _hdr, *hp;
139 /* Actually only need first 8 bytes. */
140 hp = skb_header_pointer(skb, dataoff, 8, &_hdr);
144 tuple->src.u.sctp.port = hp->source;
145 tuple->dst.u.sctp.port = hp->dest;
149 static int sctp_invert_tuple(struct nf_conntrack_tuple *tuple,
150 const struct nf_conntrack_tuple *orig)
152 tuple->src.u.sctp.port = orig->dst.u.sctp.port;
153 tuple->dst.u.sctp.port = orig->src.u.sctp.port;
157 /* Print out the per-protocol part of the tuple. */
158 static int sctp_print_tuple(struct seq_file *s,
159 const struct nf_conntrack_tuple *tuple)
161 return seq_printf(s, "sport=%hu dport=%hu ",
162 ntohs(tuple->src.u.sctp.port),
163 ntohs(tuple->dst.u.sctp.port));
166 /* Print out the private part of the conntrack. */
167 static int sctp_print_conntrack(struct seq_file *s, const struct nf_conn *ct)
169 enum sctp_conntrack state;
171 read_lock_bh(&sctp_lock);
172 state = ct->proto.sctp.state;
173 read_unlock_bh(&sctp_lock);
175 return seq_printf(s, "%s ", sctp_conntrack_names[state]);
178 #define for_each_sctp_chunk(skb, sch, _sch, offset, dataoff, count) \
179 for ((offset) = (dataoff) + sizeof(sctp_sctphdr_t), (count) = 0; \
180 (offset) < (skb)->len && \
181 ((sch) = skb_header_pointer((skb), (offset), sizeof(_sch), &(_sch))); \
182 (offset) += (ntohs((sch)->length) + 3) & ~3, (count)++)
184 /* Some validity checks to make sure the chunks are fine */
185 static int do_basic_checks(struct nf_conn *ct,
186 const struct sk_buff *skb,
187 unsigned int dataoff,
190 u_int32_t offset, count;
191 sctp_chunkhdr_t _sch, *sch;
196 for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
197 pr_debug("Chunk Num: %d Type: %d\n", count, sch->type);
199 if (sch->type == SCTP_CID_INIT ||
200 sch->type == SCTP_CID_INIT_ACK ||
201 sch->type == SCTP_CID_SHUTDOWN_COMPLETE)
205 * Cookie Ack/Echo chunks not the first OR
206 * Init / Init Ack / Shutdown compl chunks not the only chunks
209 if (((sch->type == SCTP_CID_COOKIE_ACK ||
210 sch->type == SCTP_CID_COOKIE_ECHO ||
212 count != 0) || !sch->length) {
213 pr_debug("Basic checks failed\n");
218 set_bit(sch->type, map);
221 pr_debug("Basic checks passed\n");
225 static int sctp_new_state(enum ip_conntrack_dir dir,
226 enum sctp_conntrack cur_state,
231 pr_debug("Chunk type: %d\n", chunk_type);
233 switch (chunk_type) {
235 pr_debug("SCTP_CID_INIT\n");
238 case SCTP_CID_INIT_ACK:
239 pr_debug("SCTP_CID_INIT_ACK\n");
243 pr_debug("SCTP_CID_ABORT\n");
246 case SCTP_CID_SHUTDOWN:
247 pr_debug("SCTP_CID_SHUTDOWN\n");
250 case SCTP_CID_SHUTDOWN_ACK:
251 pr_debug("SCTP_CID_SHUTDOWN_ACK\n");
255 pr_debug("SCTP_CID_ERROR\n");
258 case SCTP_CID_COOKIE_ECHO:
259 pr_debug("SCTP_CID_COOKIE_ECHO\n");
262 case SCTP_CID_COOKIE_ACK:
263 pr_debug("SCTP_CID_COOKIE_ACK\n");
266 case SCTP_CID_SHUTDOWN_COMPLETE:
267 pr_debug("SCTP_CID_SHUTDOWN_COMPLETE\n");
271 /* Other chunks like DATA, SACK, HEARTBEAT and
272 its ACK do not cause a change in state */
273 pr_debug("Unknown chunk type, Will stay in %s\n",
274 sctp_conntrack_names[cur_state]);
278 pr_debug("dir: %d cur_state: %s chunk_type: %d new_state: %s\n",
279 dir, sctp_conntrack_names[cur_state], chunk_type,
280 sctp_conntrack_names[sctp_conntracks[dir][i][cur_state]]);
282 return sctp_conntracks[dir][i][cur_state];
285 /* Returns verdict for packet, or -NF_ACCEPT for invalid. */
286 static int sctp_packet(struct nf_conn *ct,
287 const struct sk_buff *skb,
288 unsigned int dataoff,
289 enum ip_conntrack_info ctinfo,
291 unsigned int hooknum)
293 enum sctp_conntrack new_state, old_state;
294 enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);
295 sctp_sctphdr_t _sctph, *sh;
296 sctp_chunkhdr_t _sch, *sch;
297 u_int32_t offset, count;
298 unsigned long map[256 / sizeof(unsigned long)] = { 0 };
300 sh = skb_header_pointer(skb, dataoff, sizeof(_sctph), &_sctph);
304 if (do_basic_checks(ct, skb, dataoff, map) != 0)
307 /* Check the verification tag (Sec 8.5) */
308 if (!test_bit(SCTP_CID_INIT, map) &&
309 !test_bit(SCTP_CID_SHUTDOWN_COMPLETE, map) &&
310 !test_bit(SCTP_CID_COOKIE_ECHO, map) &&
311 !test_bit(SCTP_CID_ABORT, map) &&
312 !test_bit(SCTP_CID_SHUTDOWN_ACK, map) &&
313 sh->vtag != ct->proto.sctp.vtag[dir]) {
314 pr_debug("Verification tag check failed\n");
318 old_state = new_state = SCTP_CONNTRACK_MAX;
319 write_lock_bh(&sctp_lock);
320 for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
321 /* Special cases of Verification tag check (Sec 8.5.1) */
322 if (sch->type == SCTP_CID_INIT) {
326 } else if (sch->type == SCTP_CID_ABORT) {
328 if (sh->vtag != ct->proto.sctp.vtag[dir] &&
329 sh->vtag != ct->proto.sctp.vtag[!dir])
331 } else if (sch->type == SCTP_CID_SHUTDOWN_COMPLETE) {
333 if (sh->vtag != ct->proto.sctp.vtag[dir] &&
334 sh->vtag != ct->proto.sctp.vtag[!dir] &&
335 sch->flags & SCTP_CHUNK_FLAG_T)
337 } else if (sch->type == SCTP_CID_COOKIE_ECHO) {
339 if (sh->vtag != ct->proto.sctp.vtag[dir])
343 old_state = ct->proto.sctp.state;
344 new_state = sctp_new_state(dir, old_state, sch->type);
347 if (new_state == SCTP_CONNTRACK_MAX) {
348 pr_debug("nf_conntrack_sctp: Invalid dir=%i ctype=%u "
350 dir, sch->type, old_state);
354 /* If it is an INIT or an INIT ACK note down the vtag */
355 if (sch->type == SCTP_CID_INIT ||
356 sch->type == SCTP_CID_INIT_ACK) {
357 sctp_inithdr_t _inithdr, *ih;
359 ih = skb_header_pointer(skb, offset + sizeof(sctp_chunkhdr_t),
360 sizeof(_inithdr), &_inithdr);
363 pr_debug("Setting vtag %x for dir %d\n",
365 ct->proto.sctp.vtag[!dir] = ih->init_tag;
368 ct->proto.sctp.state = new_state;
369 if (old_state != new_state)
370 nf_conntrack_event_cache(IPCT_PROTOINFO, skb);
372 write_unlock_bh(&sctp_lock);
374 nf_ct_refresh_acct(ct, ctinfo, skb, sctp_timeouts[new_state]);
376 if (old_state == SCTP_CONNTRACK_COOKIE_ECHOED &&
377 dir == IP_CT_DIR_REPLY &&
378 new_state == SCTP_CONNTRACK_ESTABLISHED) {
379 pr_debug("Setting assured bit\n");
380 set_bit(IPS_ASSURED_BIT, &ct->status);
381 nf_conntrack_event_cache(IPCT_STATUS, skb);
387 write_unlock_bh(&sctp_lock);
392 /* Called when a new connection for this protocol found. */
393 static int sctp_new(struct nf_conn *ct, const struct sk_buff *skb,
394 unsigned int dataoff)
396 enum sctp_conntrack new_state;
397 sctp_sctphdr_t _sctph, *sh;
398 sctp_chunkhdr_t _sch, *sch;
399 u_int32_t offset, count;
400 unsigned long map[256 / sizeof(unsigned long)] = { 0 };
402 sh = skb_header_pointer(skb, dataoff, sizeof(_sctph), &_sctph);
406 if (do_basic_checks(ct, skb, dataoff, map) != 0)
409 /* If an OOTB packet has any of these chunks discard (Sec 8.4) */
410 if (test_bit(SCTP_CID_ABORT, map) ||
411 test_bit(SCTP_CID_SHUTDOWN_COMPLETE, map) ||
412 test_bit(SCTP_CID_COOKIE_ACK, map))
415 new_state = SCTP_CONNTRACK_MAX;
416 for_each_sctp_chunk (skb, sch, _sch, offset, dataoff, count) {
417 /* Don't need lock here: this conntrack not in circulation yet */
418 new_state = sctp_new_state(IP_CT_DIR_ORIGINAL,
419 SCTP_CONNTRACK_NONE, sch->type);
421 /* Invalid: delete conntrack */
422 if (new_state == SCTP_CONNTRACK_NONE ||
423 new_state == SCTP_CONNTRACK_MAX) {
424 pr_debug("nf_conntrack_sctp: invalid new deleting.\n");
428 /* Copy the vtag into the state info */
429 if (sch->type == SCTP_CID_INIT) {
431 sctp_inithdr_t _inithdr, *ih;
433 ih = skb_header_pointer(skb, offset + sizeof(sctp_chunkhdr_t),
434 sizeof(_inithdr), &_inithdr);
438 pr_debug("Setting vtag %x for new conn\n",
441 ct->proto.sctp.vtag[IP_CT_DIR_REPLY] =
448 /* If it is a shutdown ack OOTB packet, we expect a return
449 shutdown complete, otherwise an ABORT Sec 8.4 (5) and (8) */
451 pr_debug("Setting vtag %x for new conn OOTB\n",
453 ct->proto.sctp.vtag[IP_CT_DIR_REPLY] = sh->vtag;
456 ct->proto.sctp.state = new_state;
463 static unsigned int sctp_sysctl_table_users;
464 static struct ctl_table_header *sctp_sysctl_header;
465 static struct ctl_table sctp_sysctl_table[] = {
467 .procname = "nf_conntrack_sctp_timeout_closed",
468 .data = &sctp_timeouts[SCTP_CONNTRACK_CLOSED],
469 .maxlen = sizeof(unsigned int),
471 .proc_handler = &proc_dointvec_jiffies,
474 .procname = "nf_conntrack_sctp_timeout_cookie_wait",
475 .data = &sctp_timeouts[SCTP_CONNTRACK_COOKIE_WAIT],
476 .maxlen = sizeof(unsigned int),
478 .proc_handler = &proc_dointvec_jiffies,
481 .procname = "nf_conntrack_sctp_timeout_cookie_echoed",
482 .data = &sctp_timeouts[SCTP_CONNTRACK_COOKIE_ECHOED],
483 .maxlen = sizeof(unsigned int),
485 .proc_handler = &proc_dointvec_jiffies,
488 .procname = "nf_conntrack_sctp_timeout_established",
489 .data = &sctp_timeouts[SCTP_CONNTRACK_ESTABLISHED],
490 .maxlen = sizeof(unsigned int),
492 .proc_handler = &proc_dointvec_jiffies,
495 .procname = "nf_conntrack_sctp_timeout_shutdown_sent",
496 .data = &sctp_timeouts[SCTP_CONNTRACK_SHUTDOWN_SENT],
497 .maxlen = sizeof(unsigned int),
499 .proc_handler = &proc_dointvec_jiffies,
502 .procname = "nf_conntrack_sctp_timeout_shutdown_recd",
503 .data = &sctp_timeouts[SCTP_CONNTRACK_SHUTDOWN_RECD],
504 .maxlen = sizeof(unsigned int),
506 .proc_handler = &proc_dointvec_jiffies,
509 .procname = "nf_conntrack_sctp_timeout_shutdown_ack_sent",
510 .data = &sctp_timeouts[SCTP_CONNTRACK_SHUTDOWN_ACK_SENT],
511 .maxlen = sizeof(unsigned int),
513 .proc_handler = &proc_dointvec_jiffies,
520 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
521 static struct ctl_table sctp_compat_sysctl_table[] = {
523 .procname = "ip_conntrack_sctp_timeout_closed",
524 .data = &sctp_timeouts[SCTP_CONNTRACK_CLOSED],
525 .maxlen = sizeof(unsigned int),
527 .proc_handler = &proc_dointvec_jiffies,
530 .procname = "ip_conntrack_sctp_timeout_cookie_wait",
531 .data = &sctp_timeouts[SCTP_CONNTRACK_COOKIE_WAIT],
532 .maxlen = sizeof(unsigned int),
534 .proc_handler = &proc_dointvec_jiffies,
537 .procname = "ip_conntrack_sctp_timeout_cookie_echoed",
538 .data = &sctp_timeouts[SCTP_CONNTRACK_COOKIE_ECHOED],
539 .maxlen = sizeof(unsigned int),
541 .proc_handler = &proc_dointvec_jiffies,
544 .procname = "ip_conntrack_sctp_timeout_established",
545 .data = &sctp_timeouts[SCTP_CONNTRACK_ESTABLISHED],
546 .maxlen = sizeof(unsigned int),
548 .proc_handler = &proc_dointvec_jiffies,
551 .procname = "ip_conntrack_sctp_timeout_shutdown_sent",
552 .data = &sctp_timeouts[SCTP_CONNTRACK_SHUTDOWN_SENT],
553 .maxlen = sizeof(unsigned int),
555 .proc_handler = &proc_dointvec_jiffies,
558 .procname = "ip_conntrack_sctp_timeout_shutdown_recd",
559 .data = &sctp_timeouts[SCTP_CONNTRACK_SHUTDOWN_RECD],
560 .maxlen = sizeof(unsigned int),
562 .proc_handler = &proc_dointvec_jiffies,
565 .procname = "ip_conntrack_sctp_timeout_shutdown_ack_sent",
566 .data = &sctp_timeouts[SCTP_CONNTRACK_SHUTDOWN_ACK_SENT],
567 .maxlen = sizeof(unsigned int),
569 .proc_handler = &proc_dointvec_jiffies,
575 #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
578 static struct nf_conntrack_l4proto nf_conntrack_l4proto_sctp4 __read_mostly = {
580 .l4proto = IPPROTO_SCTP,
582 .pkt_to_tuple = sctp_pkt_to_tuple,
583 .invert_tuple = sctp_invert_tuple,
584 .print_tuple = sctp_print_tuple,
585 .print_conntrack = sctp_print_conntrack,
586 .packet = sctp_packet,
589 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
590 .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
591 .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
592 .nla_policy = nf_ct_port_nla_policy,
595 .ctl_table_users = &sctp_sysctl_table_users,
596 .ctl_table_header = &sctp_sysctl_header,
597 .ctl_table = sctp_sysctl_table,
598 #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
599 .ctl_compat_table = sctp_compat_sysctl_table,
604 static struct nf_conntrack_l4proto nf_conntrack_l4proto_sctp6 __read_mostly = {
606 .l4proto = IPPROTO_SCTP,
608 .pkt_to_tuple = sctp_pkt_to_tuple,
609 .invert_tuple = sctp_invert_tuple,
610 .print_tuple = sctp_print_tuple,
611 .print_conntrack = sctp_print_conntrack,
612 .packet = sctp_packet,
615 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
616 .tuple_to_nlattr = nf_ct_port_tuple_to_nlattr,
617 .nlattr_to_tuple = nf_ct_port_nlattr_to_tuple,
618 .nla_policy = nf_ct_port_nla_policy,
621 .ctl_table_users = &sctp_sysctl_table_users,
622 .ctl_table_header = &sctp_sysctl_header,
623 .ctl_table = sctp_sysctl_table,
627 static int __init nf_conntrack_proto_sctp_init(void)
631 ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_sctp4);
633 printk("nf_conntrack_l4proto_sctp4: protocol register failed\n");
636 ret = nf_conntrack_l4proto_register(&nf_conntrack_l4proto_sctp6);
638 printk("nf_conntrack_l4proto_sctp6: protocol register failed\n");
645 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_sctp4);
650 static void __exit nf_conntrack_proto_sctp_fini(void)
652 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_sctp6);
653 nf_conntrack_l4proto_unregister(&nf_conntrack_l4proto_sctp4);
656 module_init(nf_conntrack_proto_sctp_init);
657 module_exit(nf_conntrack_proto_sctp_fini);
659 MODULE_LICENSE("GPL");
660 MODULE_AUTHOR("Kiran Kumar Immidi");
661 MODULE_DESCRIPTION("Netfilter connection tracking protocol helper for SCTP");
662 MODULE_ALIAS("ip_conntrack_proto_sctp");