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1da177e4 LT |
1 | /* SCTP kernel reference Implementation |
2 | * Copyright (c) 1999-2000 Cisco, Inc. | |
3 | * Copyright (c) 1999-2001 Motorola, Inc. | |
4 | * Copyright (c) 2001-2003 International Business Machines, Corp. | |
5 | * Copyright (c) 2001 Intel Corp. | |
6 | * Copyright (c) 2001 Nokia, Inc. | |
7 | * Copyright (c) 2001 La Monte H.P. Yarroll | |
8 | * | |
9 | * This file is part of the SCTP kernel reference Implementation | |
10 | * | |
11 | * These functions handle all input from the IP layer into SCTP. | |
12 | * | |
13 | * The SCTP reference implementation is free software; | |
14 | * you can redistribute it and/or modify it under the terms of | |
15 | * the GNU General Public License as published by | |
16 | * the Free Software Foundation; either version 2, or (at your option) | |
17 | * any later version. | |
18 | * | |
19 | * The SCTP reference implementation is distributed in the hope that it | |
20 | * will be useful, but WITHOUT ANY WARRANTY; without even the implied | |
21 | * ************************ | |
22 | * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. | |
23 | * See the GNU General Public License for more details. | |
24 | * | |
25 | * You should have received a copy of the GNU General Public License | |
26 | * along with GNU CC; see the file COPYING. If not, write to | |
27 | * the Free Software Foundation, 59 Temple Place - Suite 330, | |
28 | * Boston, MA 02111-1307, USA. | |
29 | * | |
30 | * Please send any bug reports or fixes you make to the | |
31 | * email address(es): | |
32 | * lksctp developers <lksctp-developers@lists.sourceforge.net> | |
33 | * | |
34 | * Or submit a bug report through the following website: | |
35 | * http://www.sf.net/projects/lksctp | |
36 | * | |
37 | * Written or modified by: | |
38 | * La Monte H.P. Yarroll <piggy@acm.org> | |
39 | * Karl Knutson <karl@athena.chicago.il.us> | |
40 | * Xingang Guo <xingang.guo@intel.com> | |
41 | * Jon Grimm <jgrimm@us.ibm.com> | |
42 | * Hui Huang <hui.huang@nokia.com> | |
43 | * Daisy Chang <daisyc@us.ibm.com> | |
44 | * Sridhar Samudrala <sri@us.ibm.com> | |
45 | * Ardelle Fan <ardelle.fan@intel.com> | |
46 | * | |
47 | * Any bugs reported given to us we will try to fix... any fixes shared will | |
48 | * be incorporated into the next SCTP release. | |
49 | */ | |
50 | ||
51 | #include <linux/types.h> | |
52 | #include <linux/list.h> /* For struct list_head */ | |
53 | #include <linux/socket.h> | |
54 | #include <linux/ip.h> | |
55 | #include <linux/time.h> /* For struct timeval */ | |
56 | #include <net/ip.h> | |
57 | #include <net/icmp.h> | |
58 | #include <net/snmp.h> | |
59 | #include <net/sock.h> | |
60 | #include <net/xfrm.h> | |
61 | #include <net/sctp/sctp.h> | |
62 | #include <net/sctp/sm.h> | |
63 | ||
64 | /* Forward declarations for internal helpers. */ | |
65 | static int sctp_rcv_ootb(struct sk_buff *); | |
66 | static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb, | |
67 | const union sctp_addr *laddr, | |
68 | const union sctp_addr *paddr, | |
69 | struct sctp_transport **transportp); | |
70 | static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr); | |
71 | static struct sctp_association *__sctp_lookup_association( | |
72 | const union sctp_addr *local, | |
73 | const union sctp_addr *peer, | |
74 | struct sctp_transport **pt); | |
75 | ||
76 | ||
77 | /* Calculate the SCTP checksum of an SCTP packet. */ | |
78 | static inline int sctp_rcv_checksum(struct sk_buff *skb) | |
79 | { | |
80 | struct sctphdr *sh; | |
81 | __u32 cmp, val; | |
82 | struct sk_buff *list = skb_shinfo(skb)->frag_list; | |
83 | ||
84 | sh = (struct sctphdr *) skb->h.raw; | |
85 | cmp = ntohl(sh->checksum); | |
86 | ||
87 | val = sctp_start_cksum((__u8 *)sh, skb_headlen(skb)); | |
88 | ||
89 | for (; list; list = list->next) | |
90 | val = sctp_update_cksum((__u8 *)list->data, skb_headlen(list), | |
91 | val); | |
92 | ||
93 | val = sctp_end_cksum(val); | |
94 | ||
95 | if (val != cmp) { | |
96 | /* CRC failure, dump it. */ | |
97 | SCTP_INC_STATS_BH(SCTP_MIB_CHECKSUMERRORS); | |
98 | return -1; | |
99 | } | |
100 | return 0; | |
101 | } | |
102 | ||
103 | /* The free routine for skbuffs that sctp receives */ | |
104 | static void sctp_rfree(struct sk_buff *skb) | |
105 | { | |
106 | atomic_sub(sizeof(struct sctp_chunk),&skb->sk->sk_rmem_alloc); | |
107 | sock_rfree(skb); | |
108 | } | |
109 | ||
110 | /* The ownership wrapper routine to do receive buffer accounting */ | |
111 | static void sctp_rcv_set_owner_r(struct sk_buff *skb, struct sock *sk) | |
112 | { | |
113 | skb_set_owner_r(skb,sk); | |
114 | skb->destructor = sctp_rfree; | |
115 | atomic_add(sizeof(struct sctp_chunk),&sk->sk_rmem_alloc); | |
116 | } | |
117 | ||
79af02c2 DM |
118 | struct sctp_input_cb { |
119 | union { | |
120 | struct inet_skb_parm h4; | |
121 | #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) | |
122 | struct inet6_skb_parm h6; | |
123 | #endif | |
124 | } header; | |
125 | struct sctp_chunk *chunk; | |
126 | }; | |
127 | #define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0])) | |
128 | ||
1da177e4 LT |
129 | /* |
130 | * This is the routine which IP calls when receiving an SCTP packet. | |
131 | */ | |
132 | int sctp_rcv(struct sk_buff *skb) | |
133 | { | |
134 | struct sock *sk; | |
135 | struct sctp_association *asoc; | |
136 | struct sctp_endpoint *ep = NULL; | |
137 | struct sctp_ep_common *rcvr; | |
138 | struct sctp_transport *transport = NULL; | |
139 | struct sctp_chunk *chunk; | |
140 | struct sctphdr *sh; | |
141 | union sctp_addr src; | |
142 | union sctp_addr dest; | |
143 | int family; | |
144 | struct sctp_af *af; | |
145 | int ret = 0; | |
146 | ||
147 | if (skb->pkt_type!=PACKET_HOST) | |
148 | goto discard_it; | |
149 | ||
150 | SCTP_INC_STATS_BH(SCTP_MIB_INSCTPPACKS); | |
151 | ||
152 | sh = (struct sctphdr *) skb->h.raw; | |
153 | ||
154 | /* Pull up the IP and SCTP headers. */ | |
155 | __skb_pull(skb, skb->h.raw - skb->data); | |
156 | if (skb->len < sizeof(struct sctphdr)) | |
157 | goto discard_it; | |
158 | if (sctp_rcv_checksum(skb) < 0) | |
159 | goto discard_it; | |
160 | ||
161 | skb_pull(skb, sizeof(struct sctphdr)); | |
162 | ||
163 | /* Make sure we at least have chunk headers worth of data left. */ | |
164 | if (skb->len < sizeof(struct sctp_chunkhdr)) | |
165 | goto discard_it; | |
166 | ||
167 | family = ipver2af(skb->nh.iph->version); | |
168 | af = sctp_get_af_specific(family); | |
169 | if (unlikely(!af)) | |
170 | goto discard_it; | |
171 | ||
172 | /* Initialize local addresses for lookups. */ | |
173 | af->from_skb(&src, skb, 1); | |
174 | af->from_skb(&dest, skb, 0); | |
175 | ||
176 | /* If the packet is to or from a non-unicast address, | |
177 | * silently discard the packet. | |
178 | * | |
179 | * This is not clearly defined in the RFC except in section | |
180 | * 8.4 - OOTB handling. However, based on the book "Stream Control | |
181 | * Transmission Protocol" 2.1, "It is important to note that the | |
182 | * IP address of an SCTP transport address must be a routable | |
183 | * unicast address. In other words, IP multicast addresses and | |
184 | * IP broadcast addresses cannot be used in an SCTP transport | |
185 | * address." | |
186 | */ | |
187 | if (!af->addr_valid(&src, NULL) || !af->addr_valid(&dest, NULL)) | |
188 | goto discard_it; | |
189 | ||
190 | asoc = __sctp_rcv_lookup(skb, &src, &dest, &transport); | |
191 | ||
0fd9a65a NH |
192 | if (!asoc) |
193 | ep = __sctp_rcv_lookup_endpoint(&dest); | |
194 | ||
195 | /* Retrieve the common input handling substructure. */ | |
196 | rcvr = asoc ? &asoc->base : &ep->base; | |
197 | sk = rcvr->sk; | |
198 | ||
199 | /* | |
200 | * If a frame arrives on an interface and the receiving socket is | |
201 | * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB | |
202 | */ | |
203 | if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb))) | |
204 | { | |
205 | sock_put(sk); | |
206 | if (asoc) { | |
207 | sctp_association_put(asoc); | |
208 | asoc = NULL; | |
209 | } else { | |
210 | sctp_endpoint_put(ep); | |
211 | ep = NULL; | |
212 | } | |
213 | sk = sctp_get_ctl_sock(); | |
214 | ep = sctp_sk(sk)->ep; | |
215 | sctp_endpoint_hold(ep); | |
216 | sock_hold(sk); | |
217 | rcvr = &ep->base; | |
218 | } | |
219 | ||
220 | if (atomic_read(&sk->sk_rmem_alloc) >= sk->sk_rcvbuf) | |
221 | goto discard_release; | |
222 | ||
1da177e4 LT |
223 | /* |
224 | * RFC 2960, 8.4 - Handle "Out of the blue" Packets. | |
225 | * An SCTP packet is called an "out of the blue" (OOTB) | |
226 | * packet if it is correctly formed, i.e., passed the | |
227 | * receiver's checksum check, but the receiver is not | |
228 | * able to identify the association to which this | |
229 | * packet belongs. | |
230 | */ | |
231 | if (!asoc) { | |
1da177e4 LT |
232 | if (sctp_rcv_ootb(skb)) { |
233 | SCTP_INC_STATS_BH(SCTP_MIB_OUTOFBLUES); | |
234 | goto discard_release; | |
235 | } | |
236 | } | |
237 | ||
1da177e4 LT |
238 | /* SCTP seems to always need a timestamp right now (FIXME) */ |
239 | if (skb->stamp.tv_sec == 0) { | |
240 | do_gettimeofday(&skb->stamp); | |
241 | sock_enable_timestamp(sk); | |
242 | } | |
243 | ||
244 | if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family)) | |
245 | goto discard_release; | |
246 | ||
247 | ret = sk_filter(sk, skb, 1); | |
248 | if (ret) | |
249 | goto discard_release; | |
250 | ||
251 | /* Create an SCTP packet structure. */ | |
252 | chunk = sctp_chunkify(skb, asoc, sk); | |
253 | if (!chunk) { | |
254 | ret = -ENOMEM; | |
255 | goto discard_release; | |
256 | } | |
79af02c2 | 257 | SCTP_INPUT_CB(skb)->chunk = chunk; |
1da177e4 LT |
258 | |
259 | sctp_rcv_set_owner_r(skb,sk); | |
260 | ||
261 | /* Remember what endpoint is to handle this packet. */ | |
262 | chunk->rcvr = rcvr; | |
263 | ||
264 | /* Remember the SCTP header. */ | |
265 | chunk->sctp_hdr = sh; | |
266 | ||
267 | /* Set the source and destination addresses of the incoming chunk. */ | |
268 | sctp_init_addrs(chunk, &src, &dest); | |
269 | ||
270 | /* Remember where we came from. */ | |
271 | chunk->transport = transport; | |
272 | ||
273 | /* Acquire access to the sock lock. Note: We are safe from other | |
274 | * bottom halves on this lock, but a user may be in the lock too, | |
275 | * so check if it is busy. | |
276 | */ | |
277 | sctp_bh_lock_sock(sk); | |
278 | ||
279 | if (sock_owned_by_user(sk)) | |
79af02c2 | 280 | sk_add_backlog(sk, skb); |
1da177e4 | 281 | else |
79af02c2 | 282 | sctp_backlog_rcv(sk, skb); |
1da177e4 LT |
283 | |
284 | /* Release the sock and any reference counts we took in the | |
285 | * lookup calls. | |
286 | */ | |
287 | sctp_bh_unlock_sock(sk); | |
288 | if (asoc) | |
289 | sctp_association_put(asoc); | |
290 | else | |
291 | sctp_endpoint_put(ep); | |
292 | sock_put(sk); | |
293 | return ret; | |
294 | ||
295 | discard_it: | |
296 | kfree_skb(skb); | |
297 | return ret; | |
298 | ||
299 | discard_release: | |
300 | /* Release any structures we may be holding. */ | |
0fd9a65a NH |
301 | sock_put(sk); |
302 | if (asoc) | |
1da177e4 | 303 | sctp_association_put(asoc); |
0fd9a65a | 304 | else |
1da177e4 | 305 | sctp_endpoint_put(ep); |
1da177e4 LT |
306 | |
307 | goto discard_it; | |
308 | } | |
309 | ||
310 | /* Handle second half of inbound skb processing. If the sock was busy, | |
311 | * we may have need to delay processing until later when the sock is | |
312 | * released (on the backlog). If not busy, we call this routine | |
313 | * directly from the bottom half. | |
314 | */ | |
315 | int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb) | |
316 | { | |
79af02c2 DM |
317 | struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; |
318 | struct sctp_inq *inqueue = &chunk->rcvr->inqueue; | |
1da177e4 LT |
319 | |
320 | sctp_inq_push(inqueue, chunk); | |
321 | return 0; | |
322 | } | |
323 | ||
324 | /* Handle icmp frag needed error. */ | |
325 | void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc, | |
326 | struct sctp_transport *t, __u32 pmtu) | |
327 | { | |
328 | if (unlikely(pmtu < SCTP_DEFAULT_MINSEGMENT)) { | |
329 | printk(KERN_WARNING "%s: Reported pmtu %d too low, " | |
330 | "using default minimum of %d\n", __FUNCTION__, pmtu, | |
331 | SCTP_DEFAULT_MINSEGMENT); | |
332 | pmtu = SCTP_DEFAULT_MINSEGMENT; | |
333 | } | |
334 | ||
335 | if (!sock_owned_by_user(sk) && t && (t->pmtu != pmtu)) { | |
336 | t->pmtu = pmtu; | |
337 | sctp_assoc_sync_pmtu(asoc); | |
338 | sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD); | |
339 | } | |
340 | } | |
341 | ||
342 | /* | |
343 | * SCTP Implementer's Guide, 2.37 ICMP handling procedures | |
344 | * | |
345 | * ICMP8) If the ICMP code is a "Unrecognized next header type encountered" | |
346 | * or a "Protocol Unreachable" treat this message as an abort | |
347 | * with the T bit set. | |
348 | * | |
349 | * This function sends an event to the state machine, which will abort the | |
350 | * association. | |
351 | * | |
352 | */ | |
353 | void sctp_icmp_proto_unreachable(struct sock *sk, | |
354 | struct sctp_endpoint *ep, | |
355 | struct sctp_association *asoc, | |
356 | struct sctp_transport *t) | |
357 | { | |
358 | SCTP_DEBUG_PRINTK("%s\n", __FUNCTION__); | |
359 | ||
360 | sctp_do_sm(SCTP_EVENT_T_OTHER, | |
361 | SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH), | |
3f7a87d2 | 362 | asoc->state, asoc->ep, asoc, t, |
1da177e4 LT |
363 | GFP_ATOMIC); |
364 | ||
365 | } | |
366 | ||
367 | /* Common lookup code for icmp/icmpv6 error handler. */ | |
368 | struct sock *sctp_err_lookup(int family, struct sk_buff *skb, | |
369 | struct sctphdr *sctphdr, | |
370 | struct sctp_endpoint **epp, | |
371 | struct sctp_association **app, | |
372 | struct sctp_transport **tpp) | |
373 | { | |
374 | union sctp_addr saddr; | |
375 | union sctp_addr daddr; | |
376 | struct sctp_af *af; | |
377 | struct sock *sk = NULL; | |
378 | struct sctp_endpoint *ep = NULL; | |
379 | struct sctp_association *asoc = NULL; | |
380 | struct sctp_transport *transport = NULL; | |
381 | ||
382 | *app = NULL; *epp = NULL; *tpp = NULL; | |
383 | ||
384 | af = sctp_get_af_specific(family); | |
385 | if (unlikely(!af)) { | |
386 | return NULL; | |
387 | } | |
388 | ||
389 | /* Initialize local addresses for lookups. */ | |
390 | af->from_skb(&saddr, skb, 1); | |
391 | af->from_skb(&daddr, skb, 0); | |
392 | ||
393 | /* Look for an association that matches the incoming ICMP error | |
394 | * packet. | |
395 | */ | |
396 | asoc = __sctp_lookup_association(&saddr, &daddr, &transport); | |
397 | if (!asoc) { | |
398 | /* If there is no matching association, see if it matches any | |
399 | * endpoint. This may happen for an ICMP error generated in | |
400 | * response to an INIT_ACK. | |
401 | */ | |
402 | ep = __sctp_rcv_lookup_endpoint(&daddr); | |
403 | if (!ep) { | |
404 | return NULL; | |
405 | } | |
406 | } | |
407 | ||
408 | if (asoc) { | |
409 | sk = asoc->base.sk; | |
410 | ||
411 | if (ntohl(sctphdr->vtag) != asoc->c.peer_vtag) { | |
412 | ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); | |
413 | goto out; | |
414 | } | |
415 | } else | |
416 | sk = ep->base.sk; | |
417 | ||
418 | sctp_bh_lock_sock(sk); | |
419 | ||
420 | /* If too many ICMPs get dropped on busy | |
421 | * servers this needs to be solved differently. | |
422 | */ | |
423 | if (sock_owned_by_user(sk)) | |
424 | NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS); | |
425 | ||
426 | *epp = ep; | |
427 | *app = asoc; | |
428 | *tpp = transport; | |
429 | return sk; | |
430 | ||
431 | out: | |
432 | sock_put(sk); | |
433 | if (asoc) | |
434 | sctp_association_put(asoc); | |
435 | if (ep) | |
436 | sctp_endpoint_put(ep); | |
437 | return NULL; | |
438 | } | |
439 | ||
440 | /* Common cleanup code for icmp/icmpv6 error handler. */ | |
441 | void sctp_err_finish(struct sock *sk, struct sctp_endpoint *ep, | |
442 | struct sctp_association *asoc) | |
443 | { | |
444 | sctp_bh_unlock_sock(sk); | |
445 | sock_put(sk); | |
446 | if (asoc) | |
447 | sctp_association_put(asoc); | |
448 | if (ep) | |
449 | sctp_endpoint_put(ep); | |
450 | } | |
451 | ||
452 | /* | |
453 | * This routine is called by the ICMP module when it gets some | |
454 | * sort of error condition. If err < 0 then the socket should | |
455 | * be closed and the error returned to the user. If err > 0 | |
456 | * it's just the icmp type << 8 | icmp code. After adjustment | |
457 | * header points to the first 8 bytes of the sctp header. We need | |
458 | * to find the appropriate port. | |
459 | * | |
460 | * The locking strategy used here is very "optimistic". When | |
461 | * someone else accesses the socket the ICMP is just dropped | |
462 | * and for some paths there is no check at all. | |
463 | * A more general error queue to queue errors for later handling | |
464 | * is probably better. | |
465 | * | |
466 | */ | |
467 | void sctp_v4_err(struct sk_buff *skb, __u32 info) | |
468 | { | |
469 | struct iphdr *iph = (struct iphdr *)skb->data; | |
470 | struct sctphdr *sh = (struct sctphdr *)(skb->data + (iph->ihl <<2)); | |
471 | int type = skb->h.icmph->type; | |
472 | int code = skb->h.icmph->code; | |
473 | struct sock *sk; | |
474 | struct sctp_endpoint *ep; | |
475 | struct sctp_association *asoc; | |
476 | struct sctp_transport *transport; | |
477 | struct inet_sock *inet; | |
478 | char *saveip, *savesctp; | |
479 | int err; | |
480 | ||
481 | if (skb->len < ((iph->ihl << 2) + 8)) { | |
482 | ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); | |
483 | return; | |
484 | } | |
485 | ||
486 | /* Fix up skb to look at the embedded net header. */ | |
487 | saveip = skb->nh.raw; | |
488 | savesctp = skb->h.raw; | |
489 | skb->nh.iph = iph; | |
490 | skb->h.raw = (char *)sh; | |
491 | sk = sctp_err_lookup(AF_INET, skb, sh, &ep, &asoc, &transport); | |
492 | /* Put back, the original pointers. */ | |
493 | skb->nh.raw = saveip; | |
494 | skb->h.raw = savesctp; | |
495 | if (!sk) { | |
496 | ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); | |
497 | return; | |
498 | } | |
499 | /* Warning: The sock lock is held. Remember to call | |
500 | * sctp_err_finish! | |
501 | */ | |
502 | ||
503 | switch (type) { | |
504 | case ICMP_PARAMETERPROB: | |
505 | err = EPROTO; | |
506 | break; | |
507 | case ICMP_DEST_UNREACH: | |
508 | if (code > NR_ICMP_UNREACH) | |
509 | goto out_unlock; | |
510 | ||
511 | /* PMTU discovery (RFC1191) */ | |
512 | if (ICMP_FRAG_NEEDED == code) { | |
513 | sctp_icmp_frag_needed(sk, asoc, transport, info); | |
514 | goto out_unlock; | |
515 | } | |
516 | else { | |
517 | if (ICMP_PROT_UNREACH == code) { | |
518 | sctp_icmp_proto_unreachable(sk, ep, asoc, | |
519 | transport); | |
520 | goto out_unlock; | |
521 | } | |
522 | } | |
523 | err = icmp_err_convert[code].errno; | |
524 | break; | |
525 | case ICMP_TIME_EXCEEDED: | |
526 | /* Ignore any time exceeded errors due to fragment reassembly | |
527 | * timeouts. | |
528 | */ | |
529 | if (ICMP_EXC_FRAGTIME == code) | |
530 | goto out_unlock; | |
531 | ||
532 | err = EHOSTUNREACH; | |
533 | break; | |
534 | default: | |
535 | goto out_unlock; | |
536 | } | |
537 | ||
538 | inet = inet_sk(sk); | |
539 | if (!sock_owned_by_user(sk) && inet->recverr) { | |
540 | sk->sk_err = err; | |
541 | sk->sk_error_report(sk); | |
542 | } else { /* Only an error on timeout */ | |
543 | sk->sk_err_soft = err; | |
544 | } | |
545 | ||
546 | out_unlock: | |
547 | sctp_err_finish(sk, ep, asoc); | |
548 | } | |
549 | ||
550 | /* | |
551 | * RFC 2960, 8.4 - Handle "Out of the blue" Packets. | |
552 | * | |
553 | * This function scans all the chunks in the OOTB packet to determine if | |
554 | * the packet should be discarded right away. If a response might be needed | |
555 | * for this packet, or, if further processing is possible, the packet will | |
556 | * be queued to a proper inqueue for the next phase of handling. | |
557 | * | |
558 | * Output: | |
559 | * Return 0 - If further processing is needed. | |
560 | * Return 1 - If the packet can be discarded right away. | |
561 | */ | |
562 | int sctp_rcv_ootb(struct sk_buff *skb) | |
563 | { | |
564 | sctp_chunkhdr_t *ch; | |
565 | __u8 *ch_end; | |
566 | sctp_errhdr_t *err; | |
567 | ||
568 | ch = (sctp_chunkhdr_t *) skb->data; | |
569 | ch_end = ((__u8 *) ch) + WORD_ROUND(ntohs(ch->length)); | |
570 | ||
571 | /* Scan through all the chunks in the packet. */ | |
572 | while (ch_end > (__u8 *)ch && ch_end < skb->tail) { | |
573 | ||
574 | /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the | |
575 | * receiver MUST silently discard the OOTB packet and take no | |
576 | * further action. | |
577 | */ | |
578 | if (SCTP_CID_ABORT == ch->type) | |
579 | goto discard; | |
580 | ||
581 | /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE | |
582 | * chunk, the receiver should silently discard the packet | |
583 | * and take no further action. | |
584 | */ | |
585 | if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type) | |
586 | goto discard; | |
587 | ||
588 | /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR | |
589 | * or a COOKIE ACK the SCTP Packet should be silently | |
590 | * discarded. | |
591 | */ | |
592 | if (SCTP_CID_COOKIE_ACK == ch->type) | |
593 | goto discard; | |
594 | ||
595 | if (SCTP_CID_ERROR == ch->type) { | |
596 | sctp_walk_errors(err, ch) { | |
597 | if (SCTP_ERROR_STALE_COOKIE == err->cause) | |
598 | goto discard; | |
599 | } | |
600 | } | |
601 | ||
602 | ch = (sctp_chunkhdr_t *) ch_end; | |
603 | ch_end = ((__u8 *) ch) + WORD_ROUND(ntohs(ch->length)); | |
604 | } | |
605 | ||
606 | return 0; | |
607 | ||
608 | discard: | |
609 | return 1; | |
610 | } | |
611 | ||
612 | /* Insert endpoint into the hash table. */ | |
613 | static void __sctp_hash_endpoint(struct sctp_endpoint *ep) | |
614 | { | |
615 | struct sctp_ep_common **epp; | |
616 | struct sctp_ep_common *epb; | |
617 | struct sctp_hashbucket *head; | |
618 | ||
619 | epb = &ep->base; | |
620 | ||
621 | epb->hashent = sctp_ep_hashfn(epb->bind_addr.port); | |
622 | head = &sctp_ep_hashtable[epb->hashent]; | |
623 | ||
624 | sctp_write_lock(&head->lock); | |
625 | epp = &head->chain; | |
626 | epb->next = *epp; | |
627 | if (epb->next) | |
628 | (*epp)->pprev = &epb->next; | |
629 | *epp = epb; | |
630 | epb->pprev = epp; | |
631 | sctp_write_unlock(&head->lock); | |
632 | } | |
633 | ||
634 | /* Add an endpoint to the hash. Local BH-safe. */ | |
635 | void sctp_hash_endpoint(struct sctp_endpoint *ep) | |
636 | { | |
637 | sctp_local_bh_disable(); | |
638 | __sctp_hash_endpoint(ep); | |
639 | sctp_local_bh_enable(); | |
640 | } | |
641 | ||
642 | /* Remove endpoint from the hash table. */ | |
643 | static void __sctp_unhash_endpoint(struct sctp_endpoint *ep) | |
644 | { | |
645 | struct sctp_hashbucket *head; | |
646 | struct sctp_ep_common *epb; | |
647 | ||
648 | epb = &ep->base; | |
649 | ||
650 | epb->hashent = sctp_ep_hashfn(epb->bind_addr.port); | |
651 | ||
652 | head = &sctp_ep_hashtable[epb->hashent]; | |
653 | ||
654 | sctp_write_lock(&head->lock); | |
655 | ||
656 | if (epb->pprev) { | |
657 | if (epb->next) | |
658 | epb->next->pprev = epb->pprev; | |
659 | *epb->pprev = epb->next; | |
660 | epb->pprev = NULL; | |
661 | } | |
662 | ||
663 | sctp_write_unlock(&head->lock); | |
664 | } | |
665 | ||
666 | /* Remove endpoint from the hash. Local BH-safe. */ | |
667 | void sctp_unhash_endpoint(struct sctp_endpoint *ep) | |
668 | { | |
669 | sctp_local_bh_disable(); | |
670 | __sctp_unhash_endpoint(ep); | |
671 | sctp_local_bh_enable(); | |
672 | } | |
673 | ||
674 | /* Look up an endpoint. */ | |
675 | static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr) | |
676 | { | |
677 | struct sctp_hashbucket *head; | |
678 | struct sctp_ep_common *epb; | |
679 | struct sctp_endpoint *ep; | |
680 | int hash; | |
681 | ||
682 | hash = sctp_ep_hashfn(laddr->v4.sin_port); | |
683 | head = &sctp_ep_hashtable[hash]; | |
684 | read_lock(&head->lock); | |
685 | for (epb = head->chain; epb; epb = epb->next) { | |
686 | ep = sctp_ep(epb); | |
687 | if (sctp_endpoint_is_match(ep, laddr)) | |
688 | goto hit; | |
689 | } | |
690 | ||
691 | ep = sctp_sk((sctp_get_ctl_sock()))->ep; | |
692 | epb = &ep->base; | |
693 | ||
694 | hit: | |
695 | sctp_endpoint_hold(ep); | |
696 | sock_hold(epb->sk); | |
697 | read_unlock(&head->lock); | |
698 | return ep; | |
699 | } | |
700 | ||
701 | /* Insert association into the hash table. */ | |
702 | static void __sctp_hash_established(struct sctp_association *asoc) | |
703 | { | |
704 | struct sctp_ep_common **epp; | |
705 | struct sctp_ep_common *epb; | |
706 | struct sctp_hashbucket *head; | |
707 | ||
708 | epb = &asoc->base; | |
709 | ||
710 | /* Calculate which chain this entry will belong to. */ | |
711 | epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port, asoc->peer.port); | |
712 | ||
713 | head = &sctp_assoc_hashtable[epb->hashent]; | |
714 | ||
715 | sctp_write_lock(&head->lock); | |
716 | epp = &head->chain; | |
717 | epb->next = *epp; | |
718 | if (epb->next) | |
719 | (*epp)->pprev = &epb->next; | |
720 | *epp = epb; | |
721 | epb->pprev = epp; | |
722 | sctp_write_unlock(&head->lock); | |
723 | } | |
724 | ||
725 | /* Add an association to the hash. Local BH-safe. */ | |
726 | void sctp_hash_established(struct sctp_association *asoc) | |
727 | { | |
728 | sctp_local_bh_disable(); | |
729 | __sctp_hash_established(asoc); | |
730 | sctp_local_bh_enable(); | |
731 | } | |
732 | ||
733 | /* Remove association from the hash table. */ | |
734 | static void __sctp_unhash_established(struct sctp_association *asoc) | |
735 | { | |
736 | struct sctp_hashbucket *head; | |
737 | struct sctp_ep_common *epb; | |
738 | ||
739 | epb = &asoc->base; | |
740 | ||
741 | epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port, | |
742 | asoc->peer.port); | |
743 | ||
744 | head = &sctp_assoc_hashtable[epb->hashent]; | |
745 | ||
746 | sctp_write_lock(&head->lock); | |
747 | ||
748 | if (epb->pprev) { | |
749 | if (epb->next) | |
750 | epb->next->pprev = epb->pprev; | |
751 | *epb->pprev = epb->next; | |
752 | epb->pprev = NULL; | |
753 | } | |
754 | ||
755 | sctp_write_unlock(&head->lock); | |
756 | } | |
757 | ||
758 | /* Remove association from the hash table. Local BH-safe. */ | |
759 | void sctp_unhash_established(struct sctp_association *asoc) | |
760 | { | |
761 | sctp_local_bh_disable(); | |
762 | __sctp_unhash_established(asoc); | |
763 | sctp_local_bh_enable(); | |
764 | } | |
765 | ||
766 | /* Look up an association. */ | |
767 | static struct sctp_association *__sctp_lookup_association( | |
768 | const union sctp_addr *local, | |
769 | const union sctp_addr *peer, | |
770 | struct sctp_transport **pt) | |
771 | { | |
772 | struct sctp_hashbucket *head; | |
773 | struct sctp_ep_common *epb; | |
774 | struct sctp_association *asoc; | |
775 | struct sctp_transport *transport; | |
776 | int hash; | |
777 | ||
778 | /* Optimize here for direct hit, only listening connections can | |
779 | * have wildcards anyways. | |
780 | */ | |
781 | hash = sctp_assoc_hashfn(local->v4.sin_port, peer->v4.sin_port); | |
782 | head = &sctp_assoc_hashtable[hash]; | |
783 | read_lock(&head->lock); | |
784 | for (epb = head->chain; epb; epb = epb->next) { | |
785 | asoc = sctp_assoc(epb); | |
786 | transport = sctp_assoc_is_match(asoc, local, peer); | |
787 | if (transport) | |
788 | goto hit; | |
789 | } | |
790 | ||
791 | read_unlock(&head->lock); | |
792 | ||
793 | return NULL; | |
794 | ||
795 | hit: | |
796 | *pt = transport; | |
797 | sctp_association_hold(asoc); | |
798 | sock_hold(epb->sk); | |
799 | read_unlock(&head->lock); | |
800 | return asoc; | |
801 | } | |
802 | ||
803 | /* Look up an association. BH-safe. */ | |
804 | SCTP_STATIC | |
805 | struct sctp_association *sctp_lookup_association(const union sctp_addr *laddr, | |
806 | const union sctp_addr *paddr, | |
807 | struct sctp_transport **transportp) | |
808 | { | |
809 | struct sctp_association *asoc; | |
810 | ||
811 | sctp_local_bh_disable(); | |
812 | asoc = __sctp_lookup_association(laddr, paddr, transportp); | |
813 | sctp_local_bh_enable(); | |
814 | ||
815 | return asoc; | |
816 | } | |
817 | ||
818 | /* Is there an association matching the given local and peer addresses? */ | |
819 | int sctp_has_association(const union sctp_addr *laddr, | |
820 | const union sctp_addr *paddr) | |
821 | { | |
822 | struct sctp_association *asoc; | |
823 | struct sctp_transport *transport; | |
824 | ||
825 | if ((asoc = sctp_lookup_association(laddr, paddr, &transport))) { | |
826 | sock_put(asoc->base.sk); | |
827 | sctp_association_put(asoc); | |
828 | return 1; | |
829 | } | |
830 | ||
831 | return 0; | |
832 | } | |
833 | ||
834 | /* | |
835 | * SCTP Implementors Guide, 2.18 Handling of address | |
836 | * parameters within the INIT or INIT-ACK. | |
837 | * | |
838 | * D) When searching for a matching TCB upon reception of an INIT | |
839 | * or INIT-ACK chunk the receiver SHOULD use not only the | |
840 | * source address of the packet (containing the INIT or | |
841 | * INIT-ACK) but the receiver SHOULD also use all valid | |
842 | * address parameters contained within the chunk. | |
843 | * | |
844 | * 2.18.3 Solution description | |
845 | * | |
846 | * This new text clearly specifies to an implementor the need | |
847 | * to look within the INIT or INIT-ACK. Any implementation that | |
848 | * does not do this, may not be able to establish associations | |
849 | * in certain circumstances. | |
850 | * | |
851 | */ | |
852 | static struct sctp_association *__sctp_rcv_init_lookup(struct sk_buff *skb, | |
853 | const union sctp_addr *laddr, struct sctp_transport **transportp) | |
854 | { | |
855 | struct sctp_association *asoc; | |
856 | union sctp_addr addr; | |
857 | union sctp_addr *paddr = &addr; | |
858 | struct sctphdr *sh = (struct sctphdr *) skb->h.raw; | |
859 | sctp_chunkhdr_t *ch; | |
860 | union sctp_params params; | |
861 | sctp_init_chunk_t *init; | |
862 | struct sctp_transport *transport; | |
863 | struct sctp_af *af; | |
864 | ||
865 | ch = (sctp_chunkhdr_t *) skb->data; | |
866 | ||
867 | /* If this is INIT/INIT-ACK look inside the chunk too. */ | |
868 | switch (ch->type) { | |
869 | case SCTP_CID_INIT: | |
870 | case SCTP_CID_INIT_ACK: | |
871 | break; | |
872 | default: | |
873 | return NULL; | |
874 | } | |
875 | ||
876 | /* The code below will attempt to walk the chunk and extract | |
877 | * parameter information. Before we do that, we need to verify | |
878 | * that the chunk length doesn't cause overflow. Otherwise, we'll | |
879 | * walk off the end. | |
880 | */ | |
881 | if (WORD_ROUND(ntohs(ch->length)) > skb->len) | |
882 | return NULL; | |
883 | ||
884 | /* | |
885 | * This code will NOT touch anything inside the chunk--it is | |
886 | * strictly READ-ONLY. | |
887 | * | |
888 | * RFC 2960 3 SCTP packet Format | |
889 | * | |
890 | * Multiple chunks can be bundled into one SCTP packet up to | |
891 | * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN | |
892 | * COMPLETE chunks. These chunks MUST NOT be bundled with any | |
893 | * other chunk in a packet. See Section 6.10 for more details | |
894 | * on chunk bundling. | |
895 | */ | |
896 | ||
897 | /* Find the start of the TLVs and the end of the chunk. This is | |
898 | * the region we search for address parameters. | |
899 | */ | |
900 | init = (sctp_init_chunk_t *)skb->data; | |
901 | ||
902 | /* Walk the parameters looking for embedded addresses. */ | |
903 | sctp_walk_params(params, init, init_hdr.params) { | |
904 | ||
905 | /* Note: Ignoring hostname addresses. */ | |
906 | af = sctp_get_af_specific(param_type2af(params.p->type)); | |
907 | if (!af) | |
908 | continue; | |
909 | ||
910 | af->from_addr_param(paddr, params.addr, ntohs(sh->source), 0); | |
911 | ||
912 | asoc = __sctp_lookup_association(laddr, paddr, &transport); | |
913 | if (asoc) | |
914 | return asoc; | |
915 | } | |
916 | ||
917 | return NULL; | |
918 | } | |
919 | ||
920 | /* Lookup an association for an inbound skb. */ | |
921 | static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb, | |
922 | const union sctp_addr *paddr, | |
923 | const union sctp_addr *laddr, | |
924 | struct sctp_transport **transportp) | |
925 | { | |
926 | struct sctp_association *asoc; | |
927 | ||
928 | asoc = __sctp_lookup_association(laddr, paddr, transportp); | |
929 | ||
930 | /* Further lookup for INIT/INIT-ACK packets. | |
931 | * SCTP Implementors Guide, 2.18 Handling of address | |
932 | * parameters within the INIT or INIT-ACK. | |
933 | */ | |
934 | if (!asoc) | |
935 | asoc = __sctp_rcv_init_lookup(skb, laddr, transportp); | |
936 | ||
937 | return asoc; | |
938 | } |