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