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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 | ||
61c9fed4 VY |
76 | static void sctp_add_backlog(struct sock *sk, struct sk_buff *skb); |
77 | ||
1da177e4 LT |
78 | |
79 | /* Calculate the SCTP checksum of an SCTP packet. */ | |
80 | static inline int sctp_rcv_checksum(struct sk_buff *skb) | |
81 | { | |
82 | struct sctphdr *sh; | |
83 | __u32 cmp, val; | |
84 | struct sk_buff *list = skb_shinfo(skb)->frag_list; | |
85 | ||
86 | sh = (struct sctphdr *) skb->h.raw; | |
87 | cmp = ntohl(sh->checksum); | |
88 | ||
89 | val = sctp_start_cksum((__u8 *)sh, skb_headlen(skb)); | |
90 | ||
91 | for (; list; list = list->next) | |
92 | val = sctp_update_cksum((__u8 *)list->data, skb_headlen(list), | |
93 | val); | |
94 | ||
95 | val = sctp_end_cksum(val); | |
96 | ||
97 | if (val != cmp) { | |
98 | /* CRC failure, dump it. */ | |
99 | SCTP_INC_STATS_BH(SCTP_MIB_CHECKSUMERRORS); | |
100 | return -1; | |
101 | } | |
102 | return 0; | |
103 | } | |
104 | ||
79af02c2 DM |
105 | struct sctp_input_cb { |
106 | union { | |
107 | struct inet_skb_parm h4; | |
108 | #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) | |
109 | struct inet6_skb_parm h6; | |
110 | #endif | |
111 | } header; | |
112 | struct sctp_chunk *chunk; | |
113 | }; | |
114 | #define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0])) | |
115 | ||
1da177e4 LT |
116 | /* |
117 | * This is the routine which IP calls when receiving an SCTP packet. | |
118 | */ | |
119 | int sctp_rcv(struct sk_buff *skb) | |
120 | { | |
121 | struct sock *sk; | |
122 | struct sctp_association *asoc; | |
123 | struct sctp_endpoint *ep = NULL; | |
124 | struct sctp_ep_common *rcvr; | |
125 | struct sctp_transport *transport = NULL; | |
126 | struct sctp_chunk *chunk; | |
127 | struct sctphdr *sh; | |
128 | union sctp_addr src; | |
129 | union sctp_addr dest; | |
130 | int family; | |
131 | struct sctp_af *af; | |
1da177e4 LT |
132 | |
133 | if (skb->pkt_type!=PACKET_HOST) | |
134 | goto discard_it; | |
135 | ||
136 | SCTP_INC_STATS_BH(SCTP_MIB_INSCTPPACKS); | |
137 | ||
138 | sh = (struct sctphdr *) skb->h.raw; | |
139 | ||
140 | /* Pull up the IP and SCTP headers. */ | |
141 | __skb_pull(skb, skb->h.raw - skb->data); | |
142 | if (skb->len < sizeof(struct sctphdr)) | |
143 | goto discard_it; | |
144 | if (sctp_rcv_checksum(skb) < 0) | |
145 | goto discard_it; | |
146 | ||
147 | skb_pull(skb, sizeof(struct sctphdr)); | |
148 | ||
149 | /* Make sure we at least have chunk headers worth of data left. */ | |
150 | if (skb->len < sizeof(struct sctp_chunkhdr)) | |
151 | goto discard_it; | |
152 | ||
153 | family = ipver2af(skb->nh.iph->version); | |
154 | af = sctp_get_af_specific(family); | |
155 | if (unlikely(!af)) | |
156 | goto discard_it; | |
157 | ||
158 | /* Initialize local addresses for lookups. */ | |
159 | af->from_skb(&src, skb, 1); | |
160 | af->from_skb(&dest, skb, 0); | |
161 | ||
162 | /* If the packet is to or from a non-unicast address, | |
163 | * silently discard the packet. | |
164 | * | |
165 | * This is not clearly defined in the RFC except in section | |
166 | * 8.4 - OOTB handling. However, based on the book "Stream Control | |
167 | * Transmission Protocol" 2.1, "It is important to note that the | |
168 | * IP address of an SCTP transport address must be a routable | |
169 | * unicast address. In other words, IP multicast addresses and | |
170 | * IP broadcast addresses cannot be used in an SCTP transport | |
171 | * address." | |
172 | */ | |
173 | if (!af->addr_valid(&src, NULL) || !af->addr_valid(&dest, NULL)) | |
174 | goto discard_it; | |
175 | ||
176 | asoc = __sctp_rcv_lookup(skb, &src, &dest, &transport); | |
177 | ||
0fd9a65a NH |
178 | if (!asoc) |
179 | ep = __sctp_rcv_lookup_endpoint(&dest); | |
180 | ||
181 | /* Retrieve the common input handling substructure. */ | |
182 | rcvr = asoc ? &asoc->base : &ep->base; | |
183 | sk = rcvr->sk; | |
184 | ||
185 | /* | |
186 | * If a frame arrives on an interface and the receiving socket is | |
187 | * bound to another interface, via SO_BINDTODEVICE, treat it as OOTB | |
188 | */ | |
189 | if (sk->sk_bound_dev_if && (sk->sk_bound_dev_if != af->skb_iif(skb))) | |
190 | { | |
0fd9a65a NH |
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); | |
0fd9a65a NH |
201 | rcvr = &ep->base; |
202 | } | |
203 | ||
1da177e4 LT |
204 | /* |
205 | * RFC 2960, 8.4 - Handle "Out of the blue" Packets. | |
206 | * An SCTP packet is called an "out of the blue" (OOTB) | |
207 | * packet if it is correctly formed, i.e., passed the | |
208 | * receiver's checksum check, but the receiver is not | |
209 | * able to identify the association to which this | |
210 | * packet belongs. | |
211 | */ | |
212 | if (!asoc) { | |
1da177e4 LT |
213 | if (sctp_rcv_ootb(skb)) { |
214 | SCTP_INC_STATS_BH(SCTP_MIB_OUTOFBLUES); | |
215 | goto discard_release; | |
216 | } | |
217 | } | |
218 | ||
1da177e4 | 219 | /* SCTP seems to always need a timestamp right now (FIXME) */ |
a61bbcf2 PM |
220 | if (skb->tstamp.off_sec == 0) { |
221 | __net_timestamp(skb); | |
1da177e4 LT |
222 | sock_enable_timestamp(sk); |
223 | } | |
224 | ||
225 | if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family)) | |
226 | goto discard_release; | |
b59c2701 | 227 | nf_reset(skb); |
1da177e4 | 228 | |
2babf9da | 229 | if (sk_filter(sk, skb, 1)) |
1da177e4 LT |
230 | goto discard_release; |
231 | ||
232 | /* Create an SCTP packet structure. */ | |
233 | chunk = sctp_chunkify(skb, asoc, sk); | |
2babf9da | 234 | if (!chunk) |
1da177e4 | 235 | goto discard_release; |
79af02c2 | 236 | SCTP_INPUT_CB(skb)->chunk = chunk; |
1da177e4 | 237 | |
1da177e4 LT |
238 | /* Remember what endpoint is to handle this packet. */ |
239 | chunk->rcvr = rcvr; | |
240 | ||
241 | /* Remember the SCTP header. */ | |
242 | chunk->sctp_hdr = sh; | |
243 | ||
244 | /* Set the source and destination addresses of the incoming chunk. */ | |
245 | sctp_init_addrs(chunk, &src, &dest); | |
246 | ||
247 | /* Remember where we came from. */ | |
248 | chunk->transport = transport; | |
249 | ||
250 | /* Acquire access to the sock lock. Note: We are safe from other | |
251 | * bottom halves on this lock, but a user may be in the lock too, | |
252 | * so check if it is busy. | |
253 | */ | |
254 | sctp_bh_lock_sock(sk); | |
255 | ||
256 | if (sock_owned_by_user(sk)) | |
61c9fed4 | 257 | sctp_add_backlog(sk, skb); |
1da177e4 | 258 | else |
61c9fed4 | 259 | sctp_inq_push(&chunk->rcvr->inqueue, chunk); |
1da177e4 | 260 | |
1da177e4 | 261 | sctp_bh_unlock_sock(sk); |
61c9fed4 VY |
262 | |
263 | /* Release the asoc/ep ref we took in the lookup calls. */ | |
264 | if (asoc) | |
265 | sctp_association_put(asoc); | |
266 | else | |
267 | sctp_endpoint_put(ep); | |
7a48f923 | 268 | |
2babf9da | 269 | return 0; |
1da177e4 LT |
270 | |
271 | discard_it: | |
272 | kfree_skb(skb); | |
2babf9da | 273 | return 0; |
1da177e4 LT |
274 | |
275 | discard_release: | |
61c9fed4 | 276 | /* Release the asoc/ep ref we took in the lookup calls. */ |
0fd9a65a | 277 | if (asoc) |
1da177e4 | 278 | sctp_association_put(asoc); |
0fd9a65a | 279 | else |
1da177e4 | 280 | sctp_endpoint_put(ep); |
1da177e4 LT |
281 | |
282 | goto discard_it; | |
283 | } | |
284 | ||
61c9fed4 VY |
285 | /* Process the backlog queue of the socket. Every skb on |
286 | * the backlog holds a ref on an association or endpoint. | |
287 | * We hold this ref throughout the state machine to make | |
288 | * sure that the structure we need is still around. | |
1da177e4 LT |
289 | */ |
290 | int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb) | |
291 | { | |
79af02c2 | 292 | struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; |
61c9fed4 | 293 | struct sctp_inq *inqueue = &chunk->rcvr->inqueue; |
7a48f923 | 294 | struct sctp_ep_common *rcvr = NULL; |
61c9fed4 | 295 | int backloged = 0; |
7a48f923 SS |
296 | |
297 | rcvr = chunk->rcvr; | |
c4d2444e | 298 | |
61c9fed4 VY |
299 | /* If the rcvr is dead then the association or endpoint |
300 | * has been deleted and we can safely drop the chunk | |
301 | * and refs that we are holding. | |
302 | */ | |
303 | if (rcvr->dead) { | |
304 | sctp_chunk_free(chunk); | |
305 | goto done; | |
306 | } | |
307 | ||
308 | if (unlikely(rcvr->sk != sk)) { | |
309 | /* In this case, the association moved from one socket to | |
310 | * another. We are currently sitting on the backlog of the | |
311 | * old socket, so we need to move. | |
312 | * However, since we are here in the process context we | |
313 | * need to take make sure that the user doesn't own | |
314 | * the new socket when we process the packet. | |
315 | * If the new socket is user-owned, queue the chunk to the | |
316 | * backlog of the new socket without dropping any refs. | |
317 | * Otherwise, we can safely push the chunk on the inqueue. | |
318 | */ | |
319 | ||
320 | sk = rcvr->sk; | |
321 | sctp_bh_lock_sock(sk); | |
322 | ||
323 | if (sock_owned_by_user(sk)) { | |
324 | sk_add_backlog(sk, skb); | |
325 | backloged = 1; | |
326 | } else | |
327 | sctp_inq_push(inqueue, chunk); | |
328 | ||
329 | sctp_bh_unlock_sock(sk); | |
330 | ||
331 | /* If the chunk was backloged again, don't drop refs */ | |
332 | if (backloged) | |
333 | return 0; | |
334 | } else { | |
335 | sctp_inq_push(inqueue, chunk); | |
336 | } | |
337 | ||
338 | done: | |
339 | /* Release the refs we took in sctp_add_backlog */ | |
340 | if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type) | |
341 | sctp_association_put(sctp_assoc(rcvr)); | |
342 | else if (SCTP_EP_TYPE_SOCKET == rcvr->type) | |
343 | sctp_endpoint_put(sctp_ep(rcvr)); | |
344 | else | |
345 | BUG(); | |
346 | ||
1da177e4 LT |
347 | return 0; |
348 | } | |
349 | ||
61c9fed4 | 350 | static void sctp_add_backlog(struct sock *sk, struct sk_buff *skb) |
c4d2444e | 351 | { |
61c9fed4 VY |
352 | struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; |
353 | struct sctp_ep_common *rcvr = chunk->rcvr; | |
c4d2444e | 354 | |
61c9fed4 VY |
355 | /* Hold the assoc/ep while hanging on the backlog queue. |
356 | * This way, we know structures we need will not disappear from us | |
357 | */ | |
358 | if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type) | |
359 | sctp_association_hold(sctp_assoc(rcvr)); | |
360 | else if (SCTP_EP_TYPE_SOCKET == rcvr->type) | |
361 | sctp_endpoint_hold(sctp_ep(rcvr)); | |
362 | else | |
363 | BUG(); | |
364 | ||
365 | sk_add_backlog(sk, skb); | |
c4d2444e SS |
366 | } |
367 | ||
1da177e4 LT |
368 | /* Handle icmp frag needed error. */ |
369 | void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc, | |
370 | struct sctp_transport *t, __u32 pmtu) | |
371 | { | |
52ccb8e9 FF |
372 | if (sock_owned_by_user(sk) || !t || (t->pathmtu == pmtu)) |
373 | return; | |
374 | ||
375 | if (t->param_flags & SPP_PMTUD_ENABLE) { | |
376 | if (unlikely(pmtu < SCTP_DEFAULT_MINSEGMENT)) { | |
377 | printk(KERN_WARNING "%s: Reported pmtu %d too low, " | |
378 | "using default minimum of %d\n", | |
379 | __FUNCTION__, pmtu, | |
380 | SCTP_DEFAULT_MINSEGMENT); | |
381 | /* Use default minimum segment size and disable | |
382 | * pmtu discovery on this transport. | |
383 | */ | |
384 | t->pathmtu = SCTP_DEFAULT_MINSEGMENT; | |
385 | t->param_flags = (t->param_flags & ~SPP_HB) | | |
386 | SPP_PMTUD_DISABLE; | |
387 | } else { | |
388 | t->pathmtu = pmtu; | |
389 | } | |
1da177e4 | 390 | |
52ccb8e9 | 391 | /* Update association pmtu. */ |
1da177e4 | 392 | sctp_assoc_sync_pmtu(asoc); |
1da177e4 | 393 | } |
52ccb8e9 FF |
394 | |
395 | /* Retransmit with the new pmtu setting. | |
396 | * Normally, if PMTU discovery is disabled, an ICMP Fragmentation | |
397 | * Needed will never be sent, but if a message was sent before | |
398 | * PMTU discovery was disabled that was larger than the PMTU, it | |
399 | * would not be fragmented, so it must be re-transmitted fragmented. | |
400 | */ | |
401 | sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD); | |
1da177e4 LT |
402 | } |
403 | ||
404 | /* | |
405 | * SCTP Implementer's Guide, 2.37 ICMP handling procedures | |
406 | * | |
407 | * ICMP8) If the ICMP code is a "Unrecognized next header type encountered" | |
408 | * or a "Protocol Unreachable" treat this message as an abort | |
409 | * with the T bit set. | |
410 | * | |
411 | * This function sends an event to the state machine, which will abort the | |
412 | * association. | |
413 | * | |
414 | */ | |
415 | void sctp_icmp_proto_unreachable(struct sock *sk, | |
1da177e4 LT |
416 | struct sctp_association *asoc, |
417 | struct sctp_transport *t) | |
418 | { | |
419 | SCTP_DEBUG_PRINTK("%s\n", __FUNCTION__); | |
420 | ||
421 | sctp_do_sm(SCTP_EVENT_T_OTHER, | |
422 | SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH), | |
3f7a87d2 | 423 | asoc->state, asoc->ep, asoc, t, |
1da177e4 LT |
424 | GFP_ATOMIC); |
425 | ||
426 | } | |
427 | ||
428 | /* Common lookup code for icmp/icmpv6 error handler. */ | |
429 | struct sock *sctp_err_lookup(int family, struct sk_buff *skb, | |
430 | struct sctphdr *sctphdr, | |
1da177e4 LT |
431 | struct sctp_association **app, |
432 | struct sctp_transport **tpp) | |
433 | { | |
434 | union sctp_addr saddr; | |
435 | union sctp_addr daddr; | |
436 | struct sctp_af *af; | |
437 | struct sock *sk = NULL; | |
8de8c873 | 438 | struct sctp_association *asoc; |
1da177e4 LT |
439 | struct sctp_transport *transport = NULL; |
440 | ||
d1ad1ff2 | 441 | *app = NULL; *tpp = NULL; |
1da177e4 LT |
442 | |
443 | af = sctp_get_af_specific(family); | |
444 | if (unlikely(!af)) { | |
445 | return NULL; | |
446 | } | |
447 | ||
448 | /* Initialize local addresses for lookups. */ | |
449 | af->from_skb(&saddr, skb, 1); | |
450 | af->from_skb(&daddr, skb, 0); | |
451 | ||
452 | /* Look for an association that matches the incoming ICMP error | |
453 | * packet. | |
454 | */ | |
455 | asoc = __sctp_lookup_association(&saddr, &daddr, &transport); | |
d1ad1ff2 SS |
456 | if (!asoc) |
457 | return NULL; | |
1da177e4 | 458 | |
d1ad1ff2 | 459 | sk = asoc->base.sk; |
1da177e4 | 460 | |
d1ad1ff2 SS |
461 | if (ntohl(sctphdr->vtag) != asoc->c.peer_vtag) { |
462 | ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); | |
463 | goto out; | |
464 | } | |
1da177e4 LT |
465 | |
466 | sctp_bh_lock_sock(sk); | |
467 | ||
468 | /* If too many ICMPs get dropped on busy | |
469 | * servers this needs to be solved differently. | |
470 | */ | |
471 | if (sock_owned_by_user(sk)) | |
472 | NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS); | |
473 | ||
1da177e4 LT |
474 | *app = asoc; |
475 | *tpp = transport; | |
476 | return sk; | |
477 | ||
478 | out: | |
1da177e4 LT |
479 | if (asoc) |
480 | sctp_association_put(asoc); | |
1da177e4 LT |
481 | return NULL; |
482 | } | |
483 | ||
484 | /* Common cleanup code for icmp/icmpv6 error handler. */ | |
d1ad1ff2 | 485 | void sctp_err_finish(struct sock *sk, struct sctp_association *asoc) |
1da177e4 LT |
486 | { |
487 | sctp_bh_unlock_sock(sk); | |
1da177e4 LT |
488 | if (asoc) |
489 | sctp_association_put(asoc); | |
1da177e4 LT |
490 | } |
491 | ||
492 | /* | |
493 | * This routine is called by the ICMP module when it gets some | |
494 | * sort of error condition. If err < 0 then the socket should | |
495 | * be closed and the error returned to the user. If err > 0 | |
496 | * it's just the icmp type << 8 | icmp code. After adjustment | |
497 | * header points to the first 8 bytes of the sctp header. We need | |
498 | * to find the appropriate port. | |
499 | * | |
500 | * The locking strategy used here is very "optimistic". When | |
501 | * someone else accesses the socket the ICMP is just dropped | |
502 | * and for some paths there is no check at all. | |
503 | * A more general error queue to queue errors for later handling | |
504 | * is probably better. | |
505 | * | |
506 | */ | |
507 | void sctp_v4_err(struct sk_buff *skb, __u32 info) | |
508 | { | |
509 | struct iphdr *iph = (struct iphdr *)skb->data; | |
510 | struct sctphdr *sh = (struct sctphdr *)(skb->data + (iph->ihl <<2)); | |
511 | int type = skb->h.icmph->type; | |
512 | int code = skb->h.icmph->code; | |
513 | struct sock *sk; | |
8de8c873 | 514 | struct sctp_association *asoc = NULL; |
1da177e4 LT |
515 | struct sctp_transport *transport; |
516 | struct inet_sock *inet; | |
517 | char *saveip, *savesctp; | |
518 | int err; | |
519 | ||
520 | if (skb->len < ((iph->ihl << 2) + 8)) { | |
521 | ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); | |
522 | return; | |
523 | } | |
524 | ||
525 | /* Fix up skb to look at the embedded net header. */ | |
526 | saveip = skb->nh.raw; | |
527 | savesctp = skb->h.raw; | |
528 | skb->nh.iph = iph; | |
529 | skb->h.raw = (char *)sh; | |
d1ad1ff2 | 530 | sk = sctp_err_lookup(AF_INET, skb, sh, &asoc, &transport); |
1da177e4 LT |
531 | /* Put back, the original pointers. */ |
532 | skb->nh.raw = saveip; | |
533 | skb->h.raw = savesctp; | |
534 | if (!sk) { | |
535 | ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); | |
536 | return; | |
537 | } | |
538 | /* Warning: The sock lock is held. Remember to call | |
539 | * sctp_err_finish! | |
540 | */ | |
541 | ||
542 | switch (type) { | |
543 | case ICMP_PARAMETERPROB: | |
544 | err = EPROTO; | |
545 | break; | |
546 | case ICMP_DEST_UNREACH: | |
547 | if (code > NR_ICMP_UNREACH) | |
548 | goto out_unlock; | |
549 | ||
550 | /* PMTU discovery (RFC1191) */ | |
551 | if (ICMP_FRAG_NEEDED == code) { | |
552 | sctp_icmp_frag_needed(sk, asoc, transport, info); | |
553 | goto out_unlock; | |
554 | } | |
555 | else { | |
556 | if (ICMP_PROT_UNREACH == code) { | |
d1ad1ff2 | 557 | sctp_icmp_proto_unreachable(sk, asoc, |
1da177e4 LT |
558 | transport); |
559 | goto out_unlock; | |
560 | } | |
561 | } | |
562 | err = icmp_err_convert[code].errno; | |
563 | break; | |
564 | case ICMP_TIME_EXCEEDED: | |
565 | /* Ignore any time exceeded errors due to fragment reassembly | |
566 | * timeouts. | |
567 | */ | |
568 | if (ICMP_EXC_FRAGTIME == code) | |
569 | goto out_unlock; | |
570 | ||
571 | err = EHOSTUNREACH; | |
572 | break; | |
573 | default: | |
574 | goto out_unlock; | |
575 | } | |
576 | ||
577 | inet = inet_sk(sk); | |
578 | if (!sock_owned_by_user(sk) && inet->recverr) { | |
579 | sk->sk_err = err; | |
580 | sk->sk_error_report(sk); | |
581 | } else { /* Only an error on timeout */ | |
582 | sk->sk_err_soft = err; | |
583 | } | |
584 | ||
585 | out_unlock: | |
d1ad1ff2 | 586 | sctp_err_finish(sk, asoc); |
1da177e4 LT |
587 | } |
588 | ||
589 | /* | |
590 | * RFC 2960, 8.4 - Handle "Out of the blue" Packets. | |
591 | * | |
592 | * This function scans all the chunks in the OOTB packet to determine if | |
593 | * the packet should be discarded right away. If a response might be needed | |
594 | * for this packet, or, if further processing is possible, the packet will | |
595 | * be queued to a proper inqueue for the next phase of handling. | |
596 | * | |
597 | * Output: | |
598 | * Return 0 - If further processing is needed. | |
599 | * Return 1 - If the packet can be discarded right away. | |
600 | */ | |
601 | int sctp_rcv_ootb(struct sk_buff *skb) | |
602 | { | |
603 | sctp_chunkhdr_t *ch; | |
604 | __u8 *ch_end; | |
605 | sctp_errhdr_t *err; | |
606 | ||
607 | ch = (sctp_chunkhdr_t *) skb->data; | |
1da177e4 LT |
608 | |
609 | /* Scan through all the chunks in the packet. */ | |
a7d1f1b6 TF |
610 | do { |
611 | /* Break out if chunk length is less then minimal. */ | |
612 | if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) | |
613 | break; | |
614 | ||
615 | ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); | |
616 | if (ch_end > skb->tail) | |
617 | break; | |
1da177e4 LT |
618 | |
619 | /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the | |
620 | * receiver MUST silently discard the OOTB packet and take no | |
621 | * further action. | |
622 | */ | |
623 | if (SCTP_CID_ABORT == ch->type) | |
624 | goto discard; | |
625 | ||
626 | /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE | |
627 | * chunk, the receiver should silently discard the packet | |
628 | * and take no further action. | |
629 | */ | |
630 | if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type) | |
631 | goto discard; | |
632 | ||
633 | /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR | |
634 | * or a COOKIE ACK the SCTP Packet should be silently | |
635 | * discarded. | |
636 | */ | |
637 | if (SCTP_CID_COOKIE_ACK == ch->type) | |
638 | goto discard; | |
639 | ||
640 | if (SCTP_CID_ERROR == ch->type) { | |
641 | sctp_walk_errors(err, ch) { | |
642 | if (SCTP_ERROR_STALE_COOKIE == err->cause) | |
643 | goto discard; | |
644 | } | |
645 | } | |
646 | ||
647 | ch = (sctp_chunkhdr_t *) ch_end; | |
a7d1f1b6 | 648 | } while (ch_end < skb->tail); |
1da177e4 LT |
649 | |
650 | return 0; | |
651 | ||
652 | discard: | |
653 | return 1; | |
654 | } | |
655 | ||
656 | /* Insert endpoint into the hash table. */ | |
657 | static void __sctp_hash_endpoint(struct sctp_endpoint *ep) | |
658 | { | |
659 | struct sctp_ep_common **epp; | |
660 | struct sctp_ep_common *epb; | |
661 | struct sctp_hashbucket *head; | |
662 | ||
663 | epb = &ep->base; | |
664 | ||
665 | epb->hashent = sctp_ep_hashfn(epb->bind_addr.port); | |
666 | head = &sctp_ep_hashtable[epb->hashent]; | |
667 | ||
668 | sctp_write_lock(&head->lock); | |
669 | epp = &head->chain; | |
670 | epb->next = *epp; | |
671 | if (epb->next) | |
672 | (*epp)->pprev = &epb->next; | |
673 | *epp = epb; | |
674 | epb->pprev = epp; | |
675 | sctp_write_unlock(&head->lock); | |
676 | } | |
677 | ||
678 | /* Add an endpoint to the hash. Local BH-safe. */ | |
679 | void sctp_hash_endpoint(struct sctp_endpoint *ep) | |
680 | { | |
681 | sctp_local_bh_disable(); | |
682 | __sctp_hash_endpoint(ep); | |
683 | sctp_local_bh_enable(); | |
684 | } | |
685 | ||
686 | /* Remove endpoint from the hash table. */ | |
687 | static void __sctp_unhash_endpoint(struct sctp_endpoint *ep) | |
688 | { | |
689 | struct sctp_hashbucket *head; | |
690 | struct sctp_ep_common *epb; | |
691 | ||
692 | epb = &ep->base; | |
693 | ||
694 | epb->hashent = sctp_ep_hashfn(epb->bind_addr.port); | |
695 | ||
696 | head = &sctp_ep_hashtable[epb->hashent]; | |
697 | ||
698 | sctp_write_lock(&head->lock); | |
699 | ||
700 | if (epb->pprev) { | |
701 | if (epb->next) | |
702 | epb->next->pprev = epb->pprev; | |
703 | *epb->pprev = epb->next; | |
704 | epb->pprev = NULL; | |
705 | } | |
706 | ||
707 | sctp_write_unlock(&head->lock); | |
708 | } | |
709 | ||
710 | /* Remove endpoint from the hash. Local BH-safe. */ | |
711 | void sctp_unhash_endpoint(struct sctp_endpoint *ep) | |
712 | { | |
713 | sctp_local_bh_disable(); | |
714 | __sctp_unhash_endpoint(ep); | |
715 | sctp_local_bh_enable(); | |
716 | } | |
717 | ||
718 | /* Look up an endpoint. */ | |
719 | static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr) | |
720 | { | |
721 | struct sctp_hashbucket *head; | |
722 | struct sctp_ep_common *epb; | |
723 | struct sctp_endpoint *ep; | |
724 | int hash; | |
725 | ||
726 | hash = sctp_ep_hashfn(laddr->v4.sin_port); | |
727 | head = &sctp_ep_hashtable[hash]; | |
728 | read_lock(&head->lock); | |
729 | for (epb = head->chain; epb; epb = epb->next) { | |
730 | ep = sctp_ep(epb); | |
731 | if (sctp_endpoint_is_match(ep, laddr)) | |
732 | goto hit; | |
733 | } | |
734 | ||
735 | ep = sctp_sk((sctp_get_ctl_sock()))->ep; | |
736 | epb = &ep->base; | |
737 | ||
738 | hit: | |
739 | sctp_endpoint_hold(ep); | |
1da177e4 LT |
740 | read_unlock(&head->lock); |
741 | return ep; | |
742 | } | |
743 | ||
744 | /* Insert association into the hash table. */ | |
745 | static void __sctp_hash_established(struct sctp_association *asoc) | |
746 | { | |
747 | struct sctp_ep_common **epp; | |
748 | struct sctp_ep_common *epb; | |
749 | struct sctp_hashbucket *head; | |
750 | ||
751 | epb = &asoc->base; | |
752 | ||
753 | /* Calculate which chain this entry will belong to. */ | |
754 | epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port, asoc->peer.port); | |
755 | ||
756 | head = &sctp_assoc_hashtable[epb->hashent]; | |
757 | ||
758 | sctp_write_lock(&head->lock); | |
759 | epp = &head->chain; | |
760 | epb->next = *epp; | |
761 | if (epb->next) | |
762 | (*epp)->pprev = &epb->next; | |
763 | *epp = epb; | |
764 | epb->pprev = epp; | |
765 | sctp_write_unlock(&head->lock); | |
766 | } | |
767 | ||
768 | /* Add an association to the hash. Local BH-safe. */ | |
769 | void sctp_hash_established(struct sctp_association *asoc) | |
770 | { | |
771 | sctp_local_bh_disable(); | |
772 | __sctp_hash_established(asoc); | |
773 | sctp_local_bh_enable(); | |
774 | } | |
775 | ||
776 | /* Remove association from the hash table. */ | |
777 | static void __sctp_unhash_established(struct sctp_association *asoc) | |
778 | { | |
779 | struct sctp_hashbucket *head; | |
780 | struct sctp_ep_common *epb; | |
781 | ||
782 | epb = &asoc->base; | |
783 | ||
784 | epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port, | |
785 | asoc->peer.port); | |
786 | ||
787 | head = &sctp_assoc_hashtable[epb->hashent]; | |
788 | ||
789 | sctp_write_lock(&head->lock); | |
790 | ||
791 | if (epb->pprev) { | |
792 | if (epb->next) | |
793 | epb->next->pprev = epb->pprev; | |
794 | *epb->pprev = epb->next; | |
795 | epb->pprev = NULL; | |
796 | } | |
797 | ||
798 | sctp_write_unlock(&head->lock); | |
799 | } | |
800 | ||
801 | /* Remove association from the hash table. Local BH-safe. */ | |
802 | void sctp_unhash_established(struct sctp_association *asoc) | |
803 | { | |
804 | sctp_local_bh_disable(); | |
805 | __sctp_unhash_established(asoc); | |
806 | sctp_local_bh_enable(); | |
807 | } | |
808 | ||
809 | /* Look up an association. */ | |
810 | static struct sctp_association *__sctp_lookup_association( | |
811 | const union sctp_addr *local, | |
812 | const union sctp_addr *peer, | |
813 | struct sctp_transport **pt) | |
814 | { | |
815 | struct sctp_hashbucket *head; | |
816 | struct sctp_ep_common *epb; | |
817 | struct sctp_association *asoc; | |
818 | struct sctp_transport *transport; | |
819 | int hash; | |
820 | ||
821 | /* Optimize here for direct hit, only listening connections can | |
822 | * have wildcards anyways. | |
823 | */ | |
824 | hash = sctp_assoc_hashfn(local->v4.sin_port, peer->v4.sin_port); | |
825 | head = &sctp_assoc_hashtable[hash]; | |
826 | read_lock(&head->lock); | |
827 | for (epb = head->chain; epb; epb = epb->next) { | |
828 | asoc = sctp_assoc(epb); | |
829 | transport = sctp_assoc_is_match(asoc, local, peer); | |
830 | if (transport) | |
831 | goto hit; | |
832 | } | |
833 | ||
834 | read_unlock(&head->lock); | |
835 | ||
836 | return NULL; | |
837 | ||
838 | hit: | |
839 | *pt = transport; | |
840 | sctp_association_hold(asoc); | |
1da177e4 LT |
841 | read_unlock(&head->lock); |
842 | return asoc; | |
843 | } | |
844 | ||
845 | /* Look up an association. BH-safe. */ | |
846 | SCTP_STATIC | |
847 | struct sctp_association *sctp_lookup_association(const union sctp_addr *laddr, | |
848 | const union sctp_addr *paddr, | |
849 | struct sctp_transport **transportp) | |
850 | { | |
851 | struct sctp_association *asoc; | |
852 | ||
853 | sctp_local_bh_disable(); | |
854 | asoc = __sctp_lookup_association(laddr, paddr, transportp); | |
855 | sctp_local_bh_enable(); | |
856 | ||
857 | return asoc; | |
858 | } | |
859 | ||
860 | /* Is there an association matching the given local and peer addresses? */ | |
861 | int sctp_has_association(const union sctp_addr *laddr, | |
862 | const union sctp_addr *paddr) | |
863 | { | |
864 | struct sctp_association *asoc; | |
865 | struct sctp_transport *transport; | |
866 | ||
867 | if ((asoc = sctp_lookup_association(laddr, paddr, &transport))) { | |
1da177e4 LT |
868 | sctp_association_put(asoc); |
869 | return 1; | |
870 | } | |
871 | ||
872 | return 0; | |
873 | } | |
874 | ||
875 | /* | |
876 | * SCTP Implementors Guide, 2.18 Handling of address | |
877 | * parameters within the INIT or INIT-ACK. | |
878 | * | |
879 | * D) When searching for a matching TCB upon reception of an INIT | |
880 | * or INIT-ACK chunk the receiver SHOULD use not only the | |
881 | * source address of the packet (containing the INIT or | |
882 | * INIT-ACK) but the receiver SHOULD also use all valid | |
883 | * address parameters contained within the chunk. | |
884 | * | |
885 | * 2.18.3 Solution description | |
886 | * | |
887 | * This new text clearly specifies to an implementor the need | |
888 | * to look within the INIT or INIT-ACK. Any implementation that | |
889 | * does not do this, may not be able to establish associations | |
890 | * in certain circumstances. | |
891 | * | |
892 | */ | |
893 | static struct sctp_association *__sctp_rcv_init_lookup(struct sk_buff *skb, | |
894 | const union sctp_addr *laddr, struct sctp_transport **transportp) | |
895 | { | |
896 | struct sctp_association *asoc; | |
897 | union sctp_addr addr; | |
898 | union sctp_addr *paddr = &addr; | |
899 | struct sctphdr *sh = (struct sctphdr *) skb->h.raw; | |
900 | sctp_chunkhdr_t *ch; | |
901 | union sctp_params params; | |
902 | sctp_init_chunk_t *init; | |
903 | struct sctp_transport *transport; | |
904 | struct sctp_af *af; | |
905 | ||
906 | ch = (sctp_chunkhdr_t *) skb->data; | |
907 | ||
908 | /* If this is INIT/INIT-ACK look inside the chunk too. */ | |
909 | switch (ch->type) { | |
910 | case SCTP_CID_INIT: | |
911 | case SCTP_CID_INIT_ACK: | |
912 | break; | |
913 | default: | |
914 | return NULL; | |
915 | } | |
916 | ||
917 | /* The code below will attempt to walk the chunk and extract | |
918 | * parameter information. Before we do that, we need to verify | |
919 | * that the chunk length doesn't cause overflow. Otherwise, we'll | |
920 | * walk off the end. | |
921 | */ | |
922 | if (WORD_ROUND(ntohs(ch->length)) > skb->len) | |
923 | return NULL; | |
924 | ||
925 | /* | |
926 | * This code will NOT touch anything inside the chunk--it is | |
927 | * strictly READ-ONLY. | |
928 | * | |
929 | * RFC 2960 3 SCTP packet Format | |
930 | * | |
931 | * Multiple chunks can be bundled into one SCTP packet up to | |
932 | * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN | |
933 | * COMPLETE chunks. These chunks MUST NOT be bundled with any | |
934 | * other chunk in a packet. See Section 6.10 for more details | |
935 | * on chunk bundling. | |
936 | */ | |
937 | ||
938 | /* Find the start of the TLVs and the end of the chunk. This is | |
939 | * the region we search for address parameters. | |
940 | */ | |
941 | init = (sctp_init_chunk_t *)skb->data; | |
942 | ||
943 | /* Walk the parameters looking for embedded addresses. */ | |
944 | sctp_walk_params(params, init, init_hdr.params) { | |
945 | ||
946 | /* Note: Ignoring hostname addresses. */ | |
947 | af = sctp_get_af_specific(param_type2af(params.p->type)); | |
948 | if (!af) | |
949 | continue; | |
950 | ||
951 | af->from_addr_param(paddr, params.addr, ntohs(sh->source), 0); | |
952 | ||
953 | asoc = __sctp_lookup_association(laddr, paddr, &transport); | |
954 | if (asoc) | |
955 | return asoc; | |
956 | } | |
957 | ||
958 | return NULL; | |
959 | } | |
960 | ||
961 | /* Lookup an association for an inbound skb. */ | |
962 | static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb, | |
963 | const union sctp_addr *paddr, | |
964 | const union sctp_addr *laddr, | |
965 | struct sctp_transport **transportp) | |
966 | { | |
967 | struct sctp_association *asoc; | |
968 | ||
969 | asoc = __sctp_lookup_association(laddr, paddr, transportp); | |
970 | ||
971 | /* Further lookup for INIT/INIT-ACK packets. | |
972 | * SCTP Implementors Guide, 2.18 Handling of address | |
973 | * parameters within the INIT or INIT-ACK. | |
974 | */ | |
975 | if (!asoc) | |
976 | asoc = __sctp_rcv_init_lookup(skb, laddr, transportp); | |
977 | ||
978 | return asoc; | |
979 | } |