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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 | ||
79af02c2 DM |
103 | struct sctp_input_cb { |
104 | union { | |
105 | struct inet_skb_parm h4; | |
106 | #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) | |
107 | struct inet6_skb_parm h6; | |
108 | #endif | |
109 | } header; | |
110 | struct sctp_chunk *chunk; | |
111 | }; | |
112 | #define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0])) | |
113 | ||
1da177e4 LT |
114 | /* |
115 | * This is the routine which IP calls when receiving an SCTP packet. | |
116 | */ | |
117 | int sctp_rcv(struct sk_buff *skb) | |
118 | { | |
119 | struct sock *sk; | |
120 | struct sctp_association *asoc; | |
121 | struct sctp_endpoint *ep = NULL; | |
122 | struct sctp_ep_common *rcvr; | |
123 | struct sctp_transport *transport = NULL; | |
124 | struct sctp_chunk *chunk; | |
125 | struct sctphdr *sh; | |
126 | union sctp_addr src; | |
127 | union sctp_addr dest; | |
128 | int family; | |
129 | struct sctp_af *af; | |
130 | int ret = 0; | |
131 | ||
132 | if (skb->pkt_type!=PACKET_HOST) | |
133 | goto discard_it; | |
134 | ||
135 | SCTP_INC_STATS_BH(SCTP_MIB_INSCTPPACKS); | |
136 | ||
137 | sh = (struct sctphdr *) skb->h.raw; | |
138 | ||
139 | /* Pull up the IP and SCTP headers. */ | |
140 | __skb_pull(skb, skb->h.raw - skb->data); | |
141 | if (skb->len < sizeof(struct sctphdr)) | |
142 | goto discard_it; | |
143 | if (sctp_rcv_checksum(skb) < 0) | |
144 | goto discard_it; | |
145 | ||
146 | skb_pull(skb, sizeof(struct sctphdr)); | |
147 | ||
148 | /* Make sure we at least have chunk headers worth of data left. */ | |
149 | if (skb->len < sizeof(struct sctp_chunkhdr)) | |
150 | goto discard_it; | |
151 | ||
152 | family = ipver2af(skb->nh.iph->version); | |
153 | af = sctp_get_af_specific(family); | |
154 | if (unlikely(!af)) | |
155 | goto discard_it; | |
156 | ||
157 | /* Initialize local addresses for lookups. */ | |
158 | af->from_skb(&src, skb, 1); | |
159 | af->from_skb(&dest, skb, 0); | |
160 | ||
161 | /* If the packet is to or from a non-unicast address, | |
162 | * silently discard the packet. | |
163 | * | |
164 | * This is not clearly defined in the RFC except in section | |
165 | * 8.4 - OOTB handling. However, based on the book "Stream Control | |
166 | * Transmission Protocol" 2.1, "It is important to note that the | |
167 | * IP address of an SCTP transport address must be a routable | |
168 | * unicast address. In other words, IP multicast addresses and | |
169 | * IP broadcast addresses cannot be used in an SCTP transport | |
170 | * address." | |
171 | */ | |
172 | if (!af->addr_valid(&src, NULL) || !af->addr_valid(&dest, NULL)) | |
173 | goto discard_it; | |
174 | ||
175 | asoc = __sctp_rcv_lookup(skb, &src, &dest, &transport); | |
176 | ||
0fd9a65a NH |
177 | if (!asoc) |
178 | ep = __sctp_rcv_lookup_endpoint(&dest); | |
179 | ||
180 | /* Retrieve the common input handling substructure. */ | |
181 | rcvr = asoc ? &asoc->base : &ep->base; | |
182 | sk = rcvr->sk; | |
183 | ||
184 | /* | |
185 | * If a frame arrives on an interface and the receiving socket is | |
186 | * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB | |
187 | */ | |
188 | if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb))) | |
189 | { | |
190 | sock_put(sk); | |
191 | if (asoc) { | |
192 | sctp_association_put(asoc); | |
193 | asoc = NULL; | |
194 | } else { | |
195 | sctp_endpoint_put(ep); | |
196 | ep = NULL; | |
197 | } | |
198 | sk = sctp_get_ctl_sock(); | |
199 | ep = sctp_sk(sk)->ep; | |
200 | sctp_endpoint_hold(ep); | |
201 | sock_hold(sk); | |
202 | rcvr = &ep->base; | |
203 | } | |
204 | ||
1da177e4 LT |
205 | /* |
206 | * RFC 2960, 8.4 - Handle "Out of the blue" Packets. | |
207 | * An SCTP packet is called an "out of the blue" (OOTB) | |
208 | * packet if it is correctly formed, i.e., passed the | |
209 | * receiver's checksum check, but the receiver is not | |
210 | * able to identify the association to which this | |
211 | * packet belongs. | |
212 | */ | |
213 | if (!asoc) { | |
1da177e4 LT |
214 | if (sctp_rcv_ootb(skb)) { |
215 | SCTP_INC_STATS_BH(SCTP_MIB_OUTOFBLUES); | |
216 | goto discard_release; | |
217 | } | |
218 | } | |
219 | ||
1da177e4 | 220 | /* SCTP seems to always need a timestamp right now (FIXME) */ |
a61bbcf2 PM |
221 | if (skb->tstamp.off_sec == 0) { |
222 | __net_timestamp(skb); | |
1da177e4 LT |
223 | sock_enable_timestamp(sk); |
224 | } | |
225 | ||
226 | if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family)) | |
227 | goto discard_release; | |
228 | ||
229 | ret = sk_filter(sk, skb, 1); | |
230 | if (ret) | |
231 | goto discard_release; | |
232 | ||
233 | /* Create an SCTP packet structure. */ | |
234 | chunk = sctp_chunkify(skb, asoc, sk); | |
235 | if (!chunk) { | |
236 | ret = -ENOMEM; | |
237 | goto discard_release; | |
238 | } | |
79af02c2 | 239 | SCTP_INPUT_CB(skb)->chunk = chunk; |
1da177e4 | 240 | |
1da177e4 LT |
241 | /* Remember what endpoint is to handle this packet. */ |
242 | chunk->rcvr = rcvr; | |
243 | ||
244 | /* Remember the SCTP header. */ | |
245 | chunk->sctp_hdr = sh; | |
246 | ||
247 | /* Set the source and destination addresses of the incoming chunk. */ | |
248 | sctp_init_addrs(chunk, &src, &dest); | |
249 | ||
250 | /* Remember where we came from. */ | |
251 | chunk->transport = transport; | |
252 | ||
253 | /* Acquire access to the sock lock. Note: We are safe from other | |
254 | * bottom halves on this lock, but a user may be in the lock too, | |
255 | * so check if it is busy. | |
256 | */ | |
257 | sctp_bh_lock_sock(sk); | |
258 | ||
259 | if (sock_owned_by_user(sk)) | |
79af02c2 | 260 | sk_add_backlog(sk, skb); |
1da177e4 | 261 | else |
79af02c2 | 262 | sctp_backlog_rcv(sk, skb); |
1da177e4 LT |
263 | |
264 | /* Release the sock and any reference counts we took in the | |
265 | * lookup calls. | |
266 | */ | |
267 | sctp_bh_unlock_sock(sk); | |
268 | if (asoc) | |
269 | sctp_association_put(asoc); | |
270 | else | |
271 | sctp_endpoint_put(ep); | |
272 | sock_put(sk); | |
273 | return ret; | |
274 | ||
275 | discard_it: | |
276 | kfree_skb(skb); | |
277 | return ret; | |
278 | ||
279 | discard_release: | |
280 | /* Release any structures we may be holding. */ | |
0fd9a65a NH |
281 | sock_put(sk); |
282 | if (asoc) | |
1da177e4 | 283 | sctp_association_put(asoc); |
0fd9a65a | 284 | else |
1da177e4 | 285 | sctp_endpoint_put(ep); |
1da177e4 LT |
286 | |
287 | goto discard_it; | |
288 | } | |
289 | ||
290 | /* Handle second half of inbound skb processing. If the sock was busy, | |
291 | * we may have need to delay processing until later when the sock is | |
292 | * released (on the backlog). If not busy, we call this routine | |
293 | * directly from the bottom half. | |
294 | */ | |
295 | int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb) | |
296 | { | |
79af02c2 DM |
297 | struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; |
298 | struct sctp_inq *inqueue = &chunk->rcvr->inqueue; | |
1da177e4 LT |
299 | |
300 | sctp_inq_push(inqueue, chunk); | |
301 | return 0; | |
302 | } | |
303 | ||
304 | /* Handle icmp frag needed error. */ | |
305 | void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc, | |
306 | struct sctp_transport *t, __u32 pmtu) | |
307 | { | |
308 | if (unlikely(pmtu < SCTP_DEFAULT_MINSEGMENT)) { | |
309 | printk(KERN_WARNING "%s: Reported pmtu %d too low, " | |
310 | "using default minimum of %d\n", __FUNCTION__, pmtu, | |
311 | SCTP_DEFAULT_MINSEGMENT); | |
312 | pmtu = SCTP_DEFAULT_MINSEGMENT; | |
313 | } | |
314 | ||
315 | if (!sock_owned_by_user(sk) && t && (t->pmtu != pmtu)) { | |
316 | t->pmtu = pmtu; | |
317 | sctp_assoc_sync_pmtu(asoc); | |
318 | sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD); | |
319 | } | |
320 | } | |
321 | ||
322 | /* | |
323 | * SCTP Implementer's Guide, 2.37 ICMP handling procedures | |
324 | * | |
325 | * ICMP8) If the ICMP code is a "Unrecognized next header type encountered" | |
326 | * or a "Protocol Unreachable" treat this message as an abort | |
327 | * with the T bit set. | |
328 | * | |
329 | * This function sends an event to the state machine, which will abort the | |
330 | * association. | |
331 | * | |
332 | */ | |
333 | void sctp_icmp_proto_unreachable(struct sock *sk, | |
1da177e4 LT |
334 | struct sctp_association *asoc, |
335 | struct sctp_transport *t) | |
336 | { | |
337 | SCTP_DEBUG_PRINTK("%s\n", __FUNCTION__); | |
338 | ||
339 | sctp_do_sm(SCTP_EVENT_T_OTHER, | |
340 | SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH), | |
3f7a87d2 | 341 | asoc->state, asoc->ep, asoc, t, |
1da177e4 LT |
342 | GFP_ATOMIC); |
343 | ||
344 | } | |
345 | ||
346 | /* Common lookup code for icmp/icmpv6 error handler. */ | |
347 | struct sock *sctp_err_lookup(int family, struct sk_buff *skb, | |
348 | struct sctphdr *sctphdr, | |
1da177e4 LT |
349 | struct sctp_association **app, |
350 | struct sctp_transport **tpp) | |
351 | { | |
352 | union sctp_addr saddr; | |
353 | union sctp_addr daddr; | |
354 | struct sctp_af *af; | |
355 | struct sock *sk = NULL; | |
1da177e4 LT |
356 | struct sctp_association *asoc = NULL; |
357 | struct sctp_transport *transport = NULL; | |
358 | ||
d1ad1ff2 | 359 | *app = NULL; *tpp = NULL; |
1da177e4 LT |
360 | |
361 | af = sctp_get_af_specific(family); | |
362 | if (unlikely(!af)) { | |
363 | return NULL; | |
364 | } | |
365 | ||
366 | /* Initialize local addresses for lookups. */ | |
367 | af->from_skb(&saddr, skb, 1); | |
368 | af->from_skb(&daddr, skb, 0); | |
369 | ||
370 | /* Look for an association that matches the incoming ICMP error | |
371 | * packet. | |
372 | */ | |
373 | asoc = __sctp_lookup_association(&saddr, &daddr, &transport); | |
d1ad1ff2 SS |
374 | if (!asoc) |
375 | return NULL; | |
1da177e4 | 376 | |
d1ad1ff2 | 377 | sk = asoc->base.sk; |
1da177e4 | 378 | |
d1ad1ff2 SS |
379 | if (ntohl(sctphdr->vtag) != asoc->c.peer_vtag) { |
380 | ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); | |
381 | goto out; | |
382 | } | |
1da177e4 LT |
383 | |
384 | sctp_bh_lock_sock(sk); | |
385 | ||
386 | /* If too many ICMPs get dropped on busy | |
387 | * servers this needs to be solved differently. | |
388 | */ | |
389 | if (sock_owned_by_user(sk)) | |
390 | NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS); | |
391 | ||
1da177e4 LT |
392 | *app = asoc; |
393 | *tpp = transport; | |
394 | return sk; | |
395 | ||
396 | out: | |
397 | sock_put(sk); | |
398 | if (asoc) | |
399 | sctp_association_put(asoc); | |
1da177e4 LT |
400 | return NULL; |
401 | } | |
402 | ||
403 | /* Common cleanup code for icmp/icmpv6 error handler. */ | |
d1ad1ff2 | 404 | void sctp_err_finish(struct sock *sk, struct sctp_association *asoc) |
1da177e4 LT |
405 | { |
406 | sctp_bh_unlock_sock(sk); | |
407 | sock_put(sk); | |
408 | if (asoc) | |
409 | sctp_association_put(asoc); | |
1da177e4 LT |
410 | } |
411 | ||
412 | /* | |
413 | * This routine is called by the ICMP module when it gets some | |
414 | * sort of error condition. If err < 0 then the socket should | |
415 | * be closed and the error returned to the user. If err > 0 | |
416 | * it's just the icmp type << 8 | icmp code. After adjustment | |
417 | * header points to the first 8 bytes of the sctp header. We need | |
418 | * to find the appropriate port. | |
419 | * | |
420 | * The locking strategy used here is very "optimistic". When | |
421 | * someone else accesses the socket the ICMP is just dropped | |
422 | * and for some paths there is no check at all. | |
423 | * A more general error queue to queue errors for later handling | |
424 | * is probably better. | |
425 | * | |
426 | */ | |
427 | void sctp_v4_err(struct sk_buff *skb, __u32 info) | |
428 | { | |
429 | struct iphdr *iph = (struct iphdr *)skb->data; | |
430 | struct sctphdr *sh = (struct sctphdr *)(skb->data + (iph->ihl <<2)); | |
431 | int type = skb->h.icmph->type; | |
432 | int code = skb->h.icmph->code; | |
433 | struct sock *sk; | |
1da177e4 LT |
434 | struct sctp_association *asoc; |
435 | struct sctp_transport *transport; | |
436 | struct inet_sock *inet; | |
437 | char *saveip, *savesctp; | |
438 | int err; | |
439 | ||
440 | if (skb->len < ((iph->ihl << 2) + 8)) { | |
441 | ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); | |
442 | return; | |
443 | } | |
444 | ||
445 | /* Fix up skb to look at the embedded net header. */ | |
446 | saveip = skb->nh.raw; | |
447 | savesctp = skb->h.raw; | |
448 | skb->nh.iph = iph; | |
449 | skb->h.raw = (char *)sh; | |
d1ad1ff2 | 450 | sk = sctp_err_lookup(AF_INET, skb, sh, &asoc, &transport); |
1da177e4 LT |
451 | /* Put back, the original pointers. */ |
452 | skb->nh.raw = saveip; | |
453 | skb->h.raw = savesctp; | |
454 | if (!sk) { | |
455 | ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); | |
456 | return; | |
457 | } | |
458 | /* Warning: The sock lock is held. Remember to call | |
459 | * sctp_err_finish! | |
460 | */ | |
461 | ||
462 | switch (type) { | |
463 | case ICMP_PARAMETERPROB: | |
464 | err = EPROTO; | |
465 | break; | |
466 | case ICMP_DEST_UNREACH: | |
467 | if (code > NR_ICMP_UNREACH) | |
468 | goto out_unlock; | |
469 | ||
470 | /* PMTU discovery (RFC1191) */ | |
471 | if (ICMP_FRAG_NEEDED == code) { | |
472 | sctp_icmp_frag_needed(sk, asoc, transport, info); | |
473 | goto out_unlock; | |
474 | } | |
475 | else { | |
476 | if (ICMP_PROT_UNREACH == code) { | |
d1ad1ff2 | 477 | sctp_icmp_proto_unreachable(sk, asoc, |
1da177e4 LT |
478 | transport); |
479 | goto out_unlock; | |
480 | } | |
481 | } | |
482 | err = icmp_err_convert[code].errno; | |
483 | break; | |
484 | case ICMP_TIME_EXCEEDED: | |
485 | /* Ignore any time exceeded errors due to fragment reassembly | |
486 | * timeouts. | |
487 | */ | |
488 | if (ICMP_EXC_FRAGTIME == code) | |
489 | goto out_unlock; | |
490 | ||
491 | err = EHOSTUNREACH; | |
492 | break; | |
493 | default: | |
494 | goto out_unlock; | |
495 | } | |
496 | ||
497 | inet = inet_sk(sk); | |
498 | if (!sock_owned_by_user(sk) && inet->recverr) { | |
499 | sk->sk_err = err; | |
500 | sk->sk_error_report(sk); | |
501 | } else { /* Only an error on timeout */ | |
502 | sk->sk_err_soft = err; | |
503 | } | |
504 | ||
505 | out_unlock: | |
d1ad1ff2 | 506 | sctp_err_finish(sk, asoc); |
1da177e4 LT |
507 | } |
508 | ||
509 | /* | |
510 | * RFC 2960, 8.4 - Handle "Out of the blue" Packets. | |
511 | * | |
512 | * This function scans all the chunks in the OOTB packet to determine if | |
513 | * the packet should be discarded right away. If a response might be needed | |
514 | * for this packet, or, if further processing is possible, the packet will | |
515 | * be queued to a proper inqueue for the next phase of handling. | |
516 | * | |
517 | * Output: | |
518 | * Return 0 - If further processing is needed. | |
519 | * Return 1 - If the packet can be discarded right away. | |
520 | */ | |
521 | int sctp_rcv_ootb(struct sk_buff *skb) | |
522 | { | |
523 | sctp_chunkhdr_t *ch; | |
524 | __u8 *ch_end; | |
525 | sctp_errhdr_t *err; | |
526 | ||
527 | ch = (sctp_chunkhdr_t *) skb->data; | |
528 | ch_end = ((__u8 *) ch) + WORD_ROUND(ntohs(ch->length)); | |
529 | ||
530 | /* Scan through all the chunks in the packet. */ | |
531 | while (ch_end > (__u8 *)ch && ch_end < skb->tail) { | |
532 | ||
533 | /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the | |
534 | * receiver MUST silently discard the OOTB packet and take no | |
535 | * further action. | |
536 | */ | |
537 | if (SCTP_CID_ABORT == ch->type) | |
538 | goto discard; | |
539 | ||
540 | /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE | |
541 | * chunk, the receiver should silently discard the packet | |
542 | * and take no further action. | |
543 | */ | |
544 | if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type) | |
545 | goto discard; | |
546 | ||
547 | /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR | |
548 | * or a COOKIE ACK the SCTP Packet should be silently | |
549 | * discarded. | |
550 | */ | |
551 | if (SCTP_CID_COOKIE_ACK == ch->type) | |
552 | goto discard; | |
553 | ||
554 | if (SCTP_CID_ERROR == ch->type) { | |
555 | sctp_walk_errors(err, ch) { | |
556 | if (SCTP_ERROR_STALE_COOKIE == err->cause) | |
557 | goto discard; | |
558 | } | |
559 | } | |
560 | ||
561 | ch = (sctp_chunkhdr_t *) ch_end; | |
562 | ch_end = ((__u8 *) ch) + WORD_ROUND(ntohs(ch->length)); | |
563 | } | |
564 | ||
565 | return 0; | |
566 | ||
567 | discard: | |
568 | return 1; | |
569 | } | |
570 | ||
571 | /* Insert endpoint into the hash table. */ | |
572 | static void __sctp_hash_endpoint(struct sctp_endpoint *ep) | |
573 | { | |
574 | struct sctp_ep_common **epp; | |
575 | struct sctp_ep_common *epb; | |
576 | struct sctp_hashbucket *head; | |
577 | ||
578 | epb = &ep->base; | |
579 | ||
580 | epb->hashent = sctp_ep_hashfn(epb->bind_addr.port); | |
581 | head = &sctp_ep_hashtable[epb->hashent]; | |
582 | ||
583 | sctp_write_lock(&head->lock); | |
584 | epp = &head->chain; | |
585 | epb->next = *epp; | |
586 | if (epb->next) | |
587 | (*epp)->pprev = &epb->next; | |
588 | *epp = epb; | |
589 | epb->pprev = epp; | |
590 | sctp_write_unlock(&head->lock); | |
591 | } | |
592 | ||
593 | /* Add an endpoint to the hash. Local BH-safe. */ | |
594 | void sctp_hash_endpoint(struct sctp_endpoint *ep) | |
595 | { | |
596 | sctp_local_bh_disable(); | |
597 | __sctp_hash_endpoint(ep); | |
598 | sctp_local_bh_enable(); | |
599 | } | |
600 | ||
601 | /* Remove endpoint from the hash table. */ | |
602 | static void __sctp_unhash_endpoint(struct sctp_endpoint *ep) | |
603 | { | |
604 | struct sctp_hashbucket *head; | |
605 | struct sctp_ep_common *epb; | |
606 | ||
607 | epb = &ep->base; | |
608 | ||
609 | epb->hashent = sctp_ep_hashfn(epb->bind_addr.port); | |
610 | ||
611 | head = &sctp_ep_hashtable[epb->hashent]; | |
612 | ||
613 | sctp_write_lock(&head->lock); | |
614 | ||
615 | if (epb->pprev) { | |
616 | if (epb->next) | |
617 | epb->next->pprev = epb->pprev; | |
618 | *epb->pprev = epb->next; | |
619 | epb->pprev = NULL; | |
620 | } | |
621 | ||
622 | sctp_write_unlock(&head->lock); | |
623 | } | |
624 | ||
625 | /* Remove endpoint from the hash. Local BH-safe. */ | |
626 | void sctp_unhash_endpoint(struct sctp_endpoint *ep) | |
627 | { | |
628 | sctp_local_bh_disable(); | |
629 | __sctp_unhash_endpoint(ep); | |
630 | sctp_local_bh_enable(); | |
631 | } | |
632 | ||
633 | /* Look up an endpoint. */ | |
634 | static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr) | |
635 | { | |
636 | struct sctp_hashbucket *head; | |
637 | struct sctp_ep_common *epb; | |
638 | struct sctp_endpoint *ep; | |
639 | int hash; | |
640 | ||
641 | hash = sctp_ep_hashfn(laddr->v4.sin_port); | |
642 | head = &sctp_ep_hashtable[hash]; | |
643 | read_lock(&head->lock); | |
644 | for (epb = head->chain; epb; epb = epb->next) { | |
645 | ep = sctp_ep(epb); | |
646 | if (sctp_endpoint_is_match(ep, laddr)) | |
647 | goto hit; | |
648 | } | |
649 | ||
650 | ep = sctp_sk((sctp_get_ctl_sock()))->ep; | |
651 | epb = &ep->base; | |
652 | ||
653 | hit: | |
654 | sctp_endpoint_hold(ep); | |
655 | sock_hold(epb->sk); | |
656 | read_unlock(&head->lock); | |
657 | return ep; | |
658 | } | |
659 | ||
660 | /* Insert association into the hash table. */ | |
661 | static void __sctp_hash_established(struct sctp_association *asoc) | |
662 | { | |
663 | struct sctp_ep_common **epp; | |
664 | struct sctp_ep_common *epb; | |
665 | struct sctp_hashbucket *head; | |
666 | ||
667 | epb = &asoc->base; | |
668 | ||
669 | /* Calculate which chain this entry will belong to. */ | |
670 | epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port, asoc->peer.port); | |
671 | ||
672 | head = &sctp_assoc_hashtable[epb->hashent]; | |
673 | ||
674 | sctp_write_lock(&head->lock); | |
675 | epp = &head->chain; | |
676 | epb->next = *epp; | |
677 | if (epb->next) | |
678 | (*epp)->pprev = &epb->next; | |
679 | *epp = epb; | |
680 | epb->pprev = epp; | |
681 | sctp_write_unlock(&head->lock); | |
682 | } | |
683 | ||
684 | /* Add an association to the hash. Local BH-safe. */ | |
685 | void sctp_hash_established(struct sctp_association *asoc) | |
686 | { | |
687 | sctp_local_bh_disable(); | |
688 | __sctp_hash_established(asoc); | |
689 | sctp_local_bh_enable(); | |
690 | } | |
691 | ||
692 | /* Remove association from the hash table. */ | |
693 | static void __sctp_unhash_established(struct sctp_association *asoc) | |
694 | { | |
695 | struct sctp_hashbucket *head; | |
696 | struct sctp_ep_common *epb; | |
697 | ||
698 | epb = &asoc->base; | |
699 | ||
700 | epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port, | |
701 | asoc->peer.port); | |
702 | ||
703 | head = &sctp_assoc_hashtable[epb->hashent]; | |
704 | ||
705 | sctp_write_lock(&head->lock); | |
706 | ||
707 | if (epb->pprev) { | |
708 | if (epb->next) | |
709 | epb->next->pprev = epb->pprev; | |
710 | *epb->pprev = epb->next; | |
711 | epb->pprev = NULL; | |
712 | } | |
713 | ||
714 | sctp_write_unlock(&head->lock); | |
715 | } | |
716 | ||
717 | /* Remove association from the hash table. Local BH-safe. */ | |
718 | void sctp_unhash_established(struct sctp_association *asoc) | |
719 | { | |
720 | sctp_local_bh_disable(); | |
721 | __sctp_unhash_established(asoc); | |
722 | sctp_local_bh_enable(); | |
723 | } | |
724 | ||
725 | /* Look up an association. */ | |
726 | static struct sctp_association *__sctp_lookup_association( | |
727 | const union sctp_addr *local, | |
728 | const union sctp_addr *peer, | |
729 | struct sctp_transport **pt) | |
730 | { | |
731 | struct sctp_hashbucket *head; | |
732 | struct sctp_ep_common *epb; | |
733 | struct sctp_association *asoc; | |
734 | struct sctp_transport *transport; | |
735 | int hash; | |
736 | ||
737 | /* Optimize here for direct hit, only listening connections can | |
738 | * have wildcards anyways. | |
739 | */ | |
740 | hash = sctp_assoc_hashfn(local->v4.sin_port, peer->v4.sin_port); | |
741 | head = &sctp_assoc_hashtable[hash]; | |
742 | read_lock(&head->lock); | |
743 | for (epb = head->chain; epb; epb = epb->next) { | |
744 | asoc = sctp_assoc(epb); | |
745 | transport = sctp_assoc_is_match(asoc, local, peer); | |
746 | if (transport) | |
747 | goto hit; | |
748 | } | |
749 | ||
750 | read_unlock(&head->lock); | |
751 | ||
752 | return NULL; | |
753 | ||
754 | hit: | |
755 | *pt = transport; | |
756 | sctp_association_hold(asoc); | |
757 | sock_hold(epb->sk); | |
758 | read_unlock(&head->lock); | |
759 | return asoc; | |
760 | } | |
761 | ||
762 | /* Look up an association. BH-safe. */ | |
763 | SCTP_STATIC | |
764 | struct sctp_association *sctp_lookup_association(const union sctp_addr *laddr, | |
765 | const union sctp_addr *paddr, | |
766 | struct sctp_transport **transportp) | |
767 | { | |
768 | struct sctp_association *asoc; | |
769 | ||
770 | sctp_local_bh_disable(); | |
771 | asoc = __sctp_lookup_association(laddr, paddr, transportp); | |
772 | sctp_local_bh_enable(); | |
773 | ||
774 | return asoc; | |
775 | } | |
776 | ||
777 | /* Is there an association matching the given local and peer addresses? */ | |
778 | int sctp_has_association(const union sctp_addr *laddr, | |
779 | const union sctp_addr *paddr) | |
780 | { | |
781 | struct sctp_association *asoc; | |
782 | struct sctp_transport *transport; | |
783 | ||
784 | if ((asoc = sctp_lookup_association(laddr, paddr, &transport))) { | |
785 | sock_put(asoc->base.sk); | |
786 | sctp_association_put(asoc); | |
787 | return 1; | |
788 | } | |
789 | ||
790 | return 0; | |
791 | } | |
792 | ||
793 | /* | |
794 | * SCTP Implementors Guide, 2.18 Handling of address | |
795 | * parameters within the INIT or INIT-ACK. | |
796 | * | |
797 | * D) When searching for a matching TCB upon reception of an INIT | |
798 | * or INIT-ACK chunk the receiver SHOULD use not only the | |
799 | * source address of the packet (containing the INIT or | |
800 | * INIT-ACK) but the receiver SHOULD also use all valid | |
801 | * address parameters contained within the chunk. | |
802 | * | |
803 | * 2.18.3 Solution description | |
804 | * | |
805 | * This new text clearly specifies to an implementor the need | |
806 | * to look within the INIT or INIT-ACK. Any implementation that | |
807 | * does not do this, may not be able to establish associations | |
808 | * in certain circumstances. | |
809 | * | |
810 | */ | |
811 | static struct sctp_association *__sctp_rcv_init_lookup(struct sk_buff *skb, | |
812 | const union sctp_addr *laddr, struct sctp_transport **transportp) | |
813 | { | |
814 | struct sctp_association *asoc; | |
815 | union sctp_addr addr; | |
816 | union sctp_addr *paddr = &addr; | |
817 | struct sctphdr *sh = (struct sctphdr *) skb->h.raw; | |
818 | sctp_chunkhdr_t *ch; | |
819 | union sctp_params params; | |
820 | sctp_init_chunk_t *init; | |
821 | struct sctp_transport *transport; | |
822 | struct sctp_af *af; | |
823 | ||
824 | ch = (sctp_chunkhdr_t *) skb->data; | |
825 | ||
826 | /* If this is INIT/INIT-ACK look inside the chunk too. */ | |
827 | switch (ch->type) { | |
828 | case SCTP_CID_INIT: | |
829 | case SCTP_CID_INIT_ACK: | |
830 | break; | |
831 | default: | |
832 | return NULL; | |
833 | } | |
834 | ||
835 | /* The code below will attempt to walk the chunk and extract | |
836 | * parameter information. Before we do that, we need to verify | |
837 | * that the chunk length doesn't cause overflow. Otherwise, we'll | |
838 | * walk off the end. | |
839 | */ | |
840 | if (WORD_ROUND(ntohs(ch->length)) > skb->len) | |
841 | return NULL; | |
842 | ||
843 | /* | |
844 | * This code will NOT touch anything inside the chunk--it is | |
845 | * strictly READ-ONLY. | |
846 | * | |
847 | * RFC 2960 3 SCTP packet Format | |
848 | * | |
849 | * Multiple chunks can be bundled into one SCTP packet up to | |
850 | * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN | |
851 | * COMPLETE chunks. These chunks MUST NOT be bundled with any | |
852 | * other chunk in a packet. See Section 6.10 for more details | |
853 | * on chunk bundling. | |
854 | */ | |
855 | ||
856 | /* Find the start of the TLVs and the end of the chunk. This is | |
857 | * the region we search for address parameters. | |
858 | */ | |
859 | init = (sctp_init_chunk_t *)skb->data; | |
860 | ||
861 | /* Walk the parameters looking for embedded addresses. */ | |
862 | sctp_walk_params(params, init, init_hdr.params) { | |
863 | ||
864 | /* Note: Ignoring hostname addresses. */ | |
865 | af = sctp_get_af_specific(param_type2af(params.p->type)); | |
866 | if (!af) | |
867 | continue; | |
868 | ||
869 | af->from_addr_param(paddr, params.addr, ntohs(sh->source), 0); | |
870 | ||
871 | asoc = __sctp_lookup_association(laddr, paddr, &transport); | |
872 | if (asoc) | |
873 | return asoc; | |
874 | } | |
875 | ||
876 | return NULL; | |
877 | } | |
878 | ||
879 | /* Lookup an association for an inbound skb. */ | |
880 | static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb, | |
881 | const union sctp_addr *paddr, | |
882 | const union sctp_addr *laddr, | |
883 | struct sctp_transport **transportp) | |
884 | { | |
885 | struct sctp_association *asoc; | |
886 | ||
887 | asoc = __sctp_lookup_association(laddr, paddr, transportp); | |
888 | ||
889 | /* Further lookup for INIT/INIT-ACK packets. | |
890 | * SCTP Implementors Guide, 2.18 Handling of address | |
891 | * parameters within the INIT or INIT-ACK. | |
892 | */ | |
893 | if (!asoc) | |
894 | asoc = __sctp_rcv_init_lookup(skb, laddr, transportp); | |
895 | ||
896 | return asoc; | |
897 | } |