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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 | { | |
1da177e4 | 82 | struct sk_buff *list = skb_shinfo(skb)->frag_list; |
2c0fd387 ACM |
83 | struct sctphdr *sh = sctp_hdr(skb); |
84 | __u32 cmp = ntohl(sh->checksum); | |
85 | __u32 val = sctp_start_cksum((__u8 *)sh, skb_headlen(skb)); | |
1da177e4 LT |
86 | |
87 | for (; list; list = list->next) | |
88 | val = sctp_update_cksum((__u8 *)list->data, skb_headlen(list), | |
89 | val); | |
90 | ||
91 | val = sctp_end_cksum(val); | |
92 | ||
93 | if (val != cmp) { | |
94 | /* CRC failure, dump it. */ | |
95 | SCTP_INC_STATS_BH(SCTP_MIB_CHECKSUMERRORS); | |
96 | return -1; | |
97 | } | |
98 | return 0; | |
99 | } | |
100 | ||
79af02c2 DM |
101 | struct sctp_input_cb { |
102 | union { | |
103 | struct inet_skb_parm h4; | |
104 | #if defined(CONFIG_IPV6) || defined (CONFIG_IPV6_MODULE) | |
105 | struct inet6_skb_parm h6; | |
106 | #endif | |
107 | } header; | |
108 | struct sctp_chunk *chunk; | |
109 | }; | |
110 | #define SCTP_INPUT_CB(__skb) ((struct sctp_input_cb *)&((__skb)->cb[0])) | |
111 | ||
1da177e4 LT |
112 | /* |
113 | * This is the routine which IP calls when receiving an SCTP packet. | |
114 | */ | |
115 | int sctp_rcv(struct sk_buff *skb) | |
116 | { | |
117 | struct sock *sk; | |
118 | struct sctp_association *asoc; | |
119 | struct sctp_endpoint *ep = NULL; | |
120 | struct sctp_ep_common *rcvr; | |
121 | struct sctp_transport *transport = NULL; | |
122 | struct sctp_chunk *chunk; | |
123 | struct sctphdr *sh; | |
124 | union sctp_addr src; | |
125 | union sctp_addr dest; | |
126 | int family; | |
127 | struct sctp_af *af; | |
1da177e4 LT |
128 | |
129 | if (skb->pkt_type!=PACKET_HOST) | |
130 | goto discard_it; | |
131 | ||
132 | SCTP_INC_STATS_BH(SCTP_MIB_INSCTPPACKS); | |
133 | ||
28cd7752 HX |
134 | if (skb_linearize(skb)) |
135 | goto discard_it; | |
136 | ||
2c0fd387 | 137 | sh = sctp_hdr(skb); |
1da177e4 LT |
138 | |
139 | /* Pull up the IP and SCTP headers. */ | |
ea2ae17d | 140 | __skb_pull(skb, skb_transport_offset(skb)); |
1da177e4 LT |
141 | if (skb->len < sizeof(struct sctphdr)) |
142 | goto discard_it; | |
60476372 | 143 | if (!skb_csum_unnecessary(skb) && sctp_rcv_checksum(skb) < 0) |
1da177e4 LT |
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 | ||
eddc9ec5 | 152 | family = ipver2af(ip_hdr(skb)->version); |
1da177e4 LT |
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 | */ | |
5636bef7 VY |
172 | if (!af->addr_valid(&src, NULL, skb) || |
173 | !af->addr_valid(&dest, NULL, skb)) | |
1da177e4 LT |
174 | goto discard_it; |
175 | ||
d55c41b1 | 176 | asoc = __sctp_rcv_lookup(skb, &src, &dest, &transport); |
1c7d1fc1 | 177 | |
0fd9a65a | 178 | if (!asoc) |
d55c41b1 | 179 | ep = __sctp_rcv_lookup_endpoint(&dest); |
0fd9a65a NH |
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 LT |
219 | if (!xfrm_policy_check(sk, XFRM_POLICY_IN, skb, family)) |
220 | goto discard_release; | |
b59c2701 | 221 | nf_reset(skb); |
1da177e4 | 222 | |
fda9ef5d | 223 | if (sk_filter(sk, skb)) |
d808ad9a | 224 | goto discard_release; |
1da177e4 LT |
225 | |
226 | /* Create an SCTP packet structure. */ | |
227 | chunk = sctp_chunkify(skb, asoc, sk); | |
2babf9da | 228 | if (!chunk) |
1da177e4 | 229 | goto discard_release; |
79af02c2 | 230 | SCTP_INPUT_CB(skb)->chunk = chunk; |
1da177e4 | 231 | |
1da177e4 LT |
232 | /* Remember what endpoint is to handle this packet. */ |
233 | chunk->rcvr = rcvr; | |
234 | ||
235 | /* Remember the SCTP header. */ | |
236 | chunk->sctp_hdr = sh; | |
237 | ||
238 | /* Set the source and destination addresses of the incoming chunk. */ | |
d55c41b1 | 239 | sctp_init_addrs(chunk, &src, &dest); |
1da177e4 LT |
240 | |
241 | /* Remember where we came from. */ | |
242 | chunk->transport = transport; | |
243 | ||
244 | /* Acquire access to the sock lock. Note: We are safe from other | |
245 | * bottom halves on this lock, but a user may be in the lock too, | |
246 | * so check if it is busy. | |
247 | */ | |
248 | sctp_bh_lock_sock(sk); | |
249 | ||
ac0b0462 SS |
250 | if (sock_owned_by_user(sk)) { |
251 | SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_BACKLOG); | |
61c9fed4 | 252 | sctp_add_backlog(sk, skb); |
ac0b0462 SS |
253 | } else { |
254 | SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_SOFTIRQ); | |
61c9fed4 | 255 | sctp_inq_push(&chunk->rcvr->inqueue, chunk); |
ac0b0462 | 256 | } |
1da177e4 | 257 | |
1da177e4 | 258 | sctp_bh_unlock_sock(sk); |
61c9fed4 VY |
259 | |
260 | /* Release the asoc/ep ref we took in the lookup calls. */ | |
261 | if (asoc) | |
262 | sctp_association_put(asoc); | |
263 | else | |
264 | sctp_endpoint_put(ep); | |
7a48f923 | 265 | |
2babf9da | 266 | return 0; |
1da177e4 LT |
267 | |
268 | discard_it: | |
ac0b0462 | 269 | SCTP_INC_STATS_BH(SCTP_MIB_IN_PKT_DISCARDS); |
1da177e4 | 270 | kfree_skb(skb); |
2babf9da | 271 | return 0; |
1da177e4 LT |
272 | |
273 | discard_release: | |
61c9fed4 | 274 | /* Release the asoc/ep ref we took in the lookup calls. */ |
0fd9a65a | 275 | if (asoc) |
1da177e4 | 276 | sctp_association_put(asoc); |
0fd9a65a | 277 | else |
1da177e4 | 278 | sctp_endpoint_put(ep); |
1da177e4 LT |
279 | |
280 | goto discard_it; | |
281 | } | |
282 | ||
61c9fed4 VY |
283 | /* Process the backlog queue of the socket. Every skb on |
284 | * the backlog holds a ref on an association or endpoint. | |
285 | * We hold this ref throughout the state machine to make | |
286 | * sure that the structure we need is still around. | |
1da177e4 LT |
287 | */ |
288 | int sctp_backlog_rcv(struct sock *sk, struct sk_buff *skb) | |
289 | { | |
79af02c2 | 290 | struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; |
d808ad9a YH |
291 | struct sctp_inq *inqueue = &chunk->rcvr->inqueue; |
292 | struct sctp_ep_common *rcvr = NULL; | |
61c9fed4 | 293 | int backloged = 0; |
7a48f923 | 294 | |
d808ad9a | 295 | rcvr = chunk->rcvr; |
c4d2444e | 296 | |
61c9fed4 VY |
297 | /* If the rcvr is dead then the association or endpoint |
298 | * has been deleted and we can safely drop the chunk | |
299 | * and refs that we are holding. | |
300 | */ | |
301 | if (rcvr->dead) { | |
302 | sctp_chunk_free(chunk); | |
303 | goto done; | |
304 | } | |
305 | ||
306 | if (unlikely(rcvr->sk != sk)) { | |
307 | /* In this case, the association moved from one socket to | |
308 | * another. We are currently sitting on the backlog of the | |
309 | * old socket, so we need to move. | |
310 | * However, since we are here in the process context we | |
311 | * need to take make sure that the user doesn't own | |
312 | * the new socket when we process the packet. | |
313 | * If the new socket is user-owned, queue the chunk to the | |
314 | * backlog of the new socket without dropping any refs. | |
315 | * Otherwise, we can safely push the chunk on the inqueue. | |
316 | */ | |
317 | ||
318 | sk = rcvr->sk; | |
319 | sctp_bh_lock_sock(sk); | |
320 | ||
321 | if (sock_owned_by_user(sk)) { | |
322 | sk_add_backlog(sk, skb); | |
323 | backloged = 1; | |
324 | } else | |
325 | sctp_inq_push(inqueue, chunk); | |
326 | ||
327 | sctp_bh_unlock_sock(sk); | |
328 | ||
329 | /* If the chunk was backloged again, don't drop refs */ | |
330 | if (backloged) | |
331 | return 0; | |
332 | } else { | |
333 | sctp_inq_push(inqueue, chunk); | |
334 | } | |
335 | ||
336 | done: | |
337 | /* Release the refs we took in sctp_add_backlog */ | |
338 | if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type) | |
339 | sctp_association_put(sctp_assoc(rcvr)); | |
340 | else if (SCTP_EP_TYPE_SOCKET == rcvr->type) | |
341 | sctp_endpoint_put(sctp_ep(rcvr)); | |
342 | else | |
343 | BUG(); | |
344 | ||
d808ad9a | 345 | return 0; |
1da177e4 LT |
346 | } |
347 | ||
61c9fed4 | 348 | static void sctp_add_backlog(struct sock *sk, struct sk_buff *skb) |
c4d2444e | 349 | { |
61c9fed4 VY |
350 | struct sctp_chunk *chunk = SCTP_INPUT_CB(skb)->chunk; |
351 | struct sctp_ep_common *rcvr = chunk->rcvr; | |
c4d2444e | 352 | |
61c9fed4 VY |
353 | /* Hold the assoc/ep while hanging on the backlog queue. |
354 | * This way, we know structures we need will not disappear from us | |
355 | */ | |
356 | if (SCTP_EP_TYPE_ASSOCIATION == rcvr->type) | |
357 | sctp_association_hold(sctp_assoc(rcvr)); | |
358 | else if (SCTP_EP_TYPE_SOCKET == rcvr->type) | |
359 | sctp_endpoint_hold(sctp_ep(rcvr)); | |
360 | else | |
361 | BUG(); | |
362 | ||
363 | sk_add_backlog(sk, skb); | |
c4d2444e SS |
364 | } |
365 | ||
1da177e4 LT |
366 | /* Handle icmp frag needed error. */ |
367 | void sctp_icmp_frag_needed(struct sock *sk, struct sctp_association *asoc, | |
368 | struct sctp_transport *t, __u32 pmtu) | |
369 | { | |
52ccb8e9 FF |
370 | if (sock_owned_by_user(sk) || !t || (t->pathmtu == pmtu)) |
371 | return; | |
372 | ||
373 | if (t->param_flags & SPP_PMTUD_ENABLE) { | |
374 | if (unlikely(pmtu < SCTP_DEFAULT_MINSEGMENT)) { | |
375 | printk(KERN_WARNING "%s: Reported pmtu %d too low, " | |
376 | "using default minimum of %d\n", | |
377 | __FUNCTION__, pmtu, | |
378 | SCTP_DEFAULT_MINSEGMENT); | |
379 | /* Use default minimum segment size and disable | |
380 | * pmtu discovery on this transport. | |
381 | */ | |
382 | t->pathmtu = SCTP_DEFAULT_MINSEGMENT; | |
b56bab46 | 383 | t->param_flags = (t->param_flags & ~SPP_PMTUD) | |
52ccb8e9 FF |
384 | SPP_PMTUD_DISABLE; |
385 | } else { | |
386 | t->pathmtu = pmtu; | |
387 | } | |
1da177e4 | 388 | |
52ccb8e9 | 389 | /* Update association pmtu. */ |
1da177e4 | 390 | sctp_assoc_sync_pmtu(asoc); |
1da177e4 | 391 | } |
52ccb8e9 FF |
392 | |
393 | /* Retransmit with the new pmtu setting. | |
394 | * Normally, if PMTU discovery is disabled, an ICMP Fragmentation | |
395 | * Needed will never be sent, but if a message was sent before | |
396 | * PMTU discovery was disabled that was larger than the PMTU, it | |
d808ad9a | 397 | * would not be fragmented, so it must be re-transmitted fragmented. |
52ccb8e9 FF |
398 | */ |
399 | sctp_retransmit(&asoc->outqueue, t, SCTP_RTXR_PMTUD); | |
1da177e4 LT |
400 | } |
401 | ||
402 | /* | |
403 | * SCTP Implementer's Guide, 2.37 ICMP handling procedures | |
404 | * | |
405 | * ICMP8) If the ICMP code is a "Unrecognized next header type encountered" | |
406 | * or a "Protocol Unreachable" treat this message as an abort | |
407 | * with the T bit set. | |
408 | * | |
409 | * This function sends an event to the state machine, which will abort the | |
410 | * association. | |
411 | * | |
412 | */ | |
413 | void sctp_icmp_proto_unreachable(struct sock *sk, | |
d808ad9a YH |
414 | struct sctp_association *asoc, |
415 | struct sctp_transport *t) | |
1da177e4 LT |
416 | { |
417 | SCTP_DEBUG_PRINTK("%s\n", __FUNCTION__); | |
418 | ||
419 | sctp_do_sm(SCTP_EVENT_T_OTHER, | |
420 | SCTP_ST_OTHER(SCTP_EVENT_ICMP_PROTO_UNREACH), | |
3f7a87d2 | 421 | asoc->state, asoc->ep, asoc, t, |
1da177e4 LT |
422 | GFP_ATOMIC); |
423 | ||
424 | } | |
425 | ||
426 | /* Common lookup code for icmp/icmpv6 error handler. */ | |
427 | struct sock *sctp_err_lookup(int family, struct sk_buff *skb, | |
428 | struct sctphdr *sctphdr, | |
1da177e4 LT |
429 | struct sctp_association **app, |
430 | struct sctp_transport **tpp) | |
431 | { | |
432 | union sctp_addr saddr; | |
433 | union sctp_addr daddr; | |
434 | struct sctp_af *af; | |
435 | struct sock *sk = NULL; | |
8de8c873 | 436 | struct sctp_association *asoc; |
1da177e4 LT |
437 | struct sctp_transport *transport = NULL; |
438 | ||
d1ad1ff2 | 439 | *app = NULL; *tpp = NULL; |
1da177e4 LT |
440 | |
441 | af = sctp_get_af_specific(family); | |
442 | if (unlikely(!af)) { | |
443 | return NULL; | |
444 | } | |
445 | ||
446 | /* Initialize local addresses for lookups. */ | |
447 | af->from_skb(&saddr, skb, 1); | |
448 | af->from_skb(&daddr, skb, 0); | |
449 | ||
450 | /* Look for an association that matches the incoming ICMP error | |
451 | * packet. | |
452 | */ | |
d55c41b1 | 453 | asoc = __sctp_lookup_association(&saddr, &daddr, &transport); |
d1ad1ff2 SS |
454 | if (!asoc) |
455 | return NULL; | |
1da177e4 | 456 | |
d1ad1ff2 | 457 | sk = asoc->base.sk; |
1da177e4 | 458 | |
d1ad1ff2 SS |
459 | if (ntohl(sctphdr->vtag) != asoc->c.peer_vtag) { |
460 | ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); | |
461 | goto out; | |
462 | } | |
1da177e4 LT |
463 | |
464 | sctp_bh_lock_sock(sk); | |
465 | ||
466 | /* If too many ICMPs get dropped on busy | |
467 | * servers this needs to be solved differently. | |
468 | */ | |
469 | if (sock_owned_by_user(sk)) | |
470 | NET_INC_STATS_BH(LINUX_MIB_LOCKDROPPEDICMPS); | |
471 | ||
1da177e4 LT |
472 | *app = asoc; |
473 | *tpp = transport; | |
474 | return sk; | |
475 | ||
476 | out: | |
1da177e4 LT |
477 | if (asoc) |
478 | sctp_association_put(asoc); | |
1da177e4 LT |
479 | return NULL; |
480 | } | |
481 | ||
482 | /* Common cleanup code for icmp/icmpv6 error handler. */ | |
d1ad1ff2 | 483 | void sctp_err_finish(struct sock *sk, struct sctp_association *asoc) |
1da177e4 LT |
484 | { |
485 | sctp_bh_unlock_sock(sk); | |
1da177e4 LT |
486 | if (asoc) |
487 | sctp_association_put(asoc); | |
1da177e4 LT |
488 | } |
489 | ||
490 | /* | |
491 | * This routine is called by the ICMP module when it gets some | |
492 | * sort of error condition. If err < 0 then the socket should | |
493 | * be closed and the error returned to the user. If err > 0 | |
494 | * it's just the icmp type << 8 | icmp code. After adjustment | |
495 | * header points to the first 8 bytes of the sctp header. We need | |
496 | * to find the appropriate port. | |
497 | * | |
498 | * The locking strategy used here is very "optimistic". When | |
499 | * someone else accesses the socket the ICMP is just dropped | |
500 | * and for some paths there is no check at all. | |
501 | * A more general error queue to queue errors for later handling | |
502 | * is probably better. | |
503 | * | |
504 | */ | |
505 | void sctp_v4_err(struct sk_buff *skb, __u32 info) | |
506 | { | |
507 | struct iphdr *iph = (struct iphdr *)skb->data; | |
a27ef749 | 508 | const int ihlen = iph->ihl * 4; |
88c7664f ACM |
509 | const int type = icmp_hdr(skb)->type; |
510 | const int code = icmp_hdr(skb)->code; | |
1da177e4 | 511 | struct sock *sk; |
8de8c873 | 512 | struct sctp_association *asoc = NULL; |
1da177e4 LT |
513 | struct sctp_transport *transport; |
514 | struct inet_sock *inet; | |
2e07fa9c | 515 | sk_buff_data_t saveip, savesctp; |
1da177e4 LT |
516 | int err; |
517 | ||
a27ef749 | 518 | if (skb->len < ihlen + 8) { |
1da177e4 LT |
519 | ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); |
520 | return; | |
521 | } | |
522 | ||
523 | /* Fix up skb to look at the embedded net header. */ | |
b0e380b1 ACM |
524 | saveip = skb->network_header; |
525 | savesctp = skb->transport_header; | |
31c7711b | 526 | skb_reset_network_header(skb); |
a27ef749 ACM |
527 | skb_set_transport_header(skb, ihlen); |
528 | sk = sctp_err_lookup(AF_INET, skb, sctp_hdr(skb), &asoc, &transport); | |
2e07fa9c | 529 | /* Put back, the original values. */ |
b0e380b1 ACM |
530 | skb->network_header = saveip; |
531 | skb->transport_header = savesctp; | |
1da177e4 LT |
532 | if (!sk) { |
533 | ICMP_INC_STATS_BH(ICMP_MIB_INERRORS); | |
534 | return; | |
535 | } | |
536 | /* Warning: The sock lock is held. Remember to call | |
537 | * sctp_err_finish! | |
538 | */ | |
539 | ||
540 | switch (type) { | |
541 | case ICMP_PARAMETERPROB: | |
542 | err = EPROTO; | |
543 | break; | |
544 | case ICMP_DEST_UNREACH: | |
545 | if (code > NR_ICMP_UNREACH) | |
546 | goto out_unlock; | |
547 | ||
548 | /* PMTU discovery (RFC1191) */ | |
549 | if (ICMP_FRAG_NEEDED == code) { | |
550 | sctp_icmp_frag_needed(sk, asoc, transport, info); | |
551 | goto out_unlock; | |
552 | } | |
553 | else { | |
554 | if (ICMP_PROT_UNREACH == code) { | |
d1ad1ff2 | 555 | sctp_icmp_proto_unreachable(sk, asoc, |
1da177e4 LT |
556 | transport); |
557 | goto out_unlock; | |
558 | } | |
559 | } | |
560 | err = icmp_err_convert[code].errno; | |
561 | break; | |
562 | case ICMP_TIME_EXCEEDED: | |
563 | /* Ignore any time exceeded errors due to fragment reassembly | |
564 | * timeouts. | |
565 | */ | |
566 | if (ICMP_EXC_FRAGTIME == code) | |
567 | goto out_unlock; | |
568 | ||
569 | err = EHOSTUNREACH; | |
570 | break; | |
571 | default: | |
572 | goto out_unlock; | |
573 | } | |
574 | ||
575 | inet = inet_sk(sk); | |
576 | if (!sock_owned_by_user(sk) && inet->recverr) { | |
577 | sk->sk_err = err; | |
578 | sk->sk_error_report(sk); | |
579 | } else { /* Only an error on timeout */ | |
580 | sk->sk_err_soft = err; | |
581 | } | |
582 | ||
583 | out_unlock: | |
d1ad1ff2 | 584 | sctp_err_finish(sk, asoc); |
1da177e4 LT |
585 | } |
586 | ||
587 | /* | |
588 | * RFC 2960, 8.4 - Handle "Out of the blue" Packets. | |
589 | * | |
590 | * This function scans all the chunks in the OOTB packet to determine if | |
591 | * the packet should be discarded right away. If a response might be needed | |
592 | * for this packet, or, if further processing is possible, the packet will | |
593 | * be queued to a proper inqueue for the next phase of handling. | |
594 | * | |
595 | * Output: | |
596 | * Return 0 - If further processing is needed. | |
597 | * Return 1 - If the packet can be discarded right away. | |
598 | */ | |
599 | int sctp_rcv_ootb(struct sk_buff *skb) | |
600 | { | |
601 | sctp_chunkhdr_t *ch; | |
602 | __u8 *ch_end; | |
603 | sctp_errhdr_t *err; | |
604 | ||
605 | ch = (sctp_chunkhdr_t *) skb->data; | |
1da177e4 LT |
606 | |
607 | /* Scan through all the chunks in the packet. */ | |
a7d1f1b6 TF |
608 | do { |
609 | /* Break out if chunk length is less then minimal. */ | |
610 | if (ntohs(ch->length) < sizeof(sctp_chunkhdr_t)) | |
611 | break; | |
612 | ||
613 | ch_end = ((__u8 *)ch) + WORD_ROUND(ntohs(ch->length)); | |
27a884dc | 614 | if (ch_end > skb_tail_pointer(skb)) |
a7d1f1b6 | 615 | break; |
1da177e4 LT |
616 | |
617 | /* RFC 8.4, 2) If the OOTB packet contains an ABORT chunk, the | |
618 | * receiver MUST silently discard the OOTB packet and take no | |
619 | * further action. | |
620 | */ | |
621 | if (SCTP_CID_ABORT == ch->type) | |
622 | goto discard; | |
623 | ||
624 | /* RFC 8.4, 6) If the packet contains a SHUTDOWN COMPLETE | |
625 | * chunk, the receiver should silently discard the packet | |
626 | * and take no further action. | |
627 | */ | |
628 | if (SCTP_CID_SHUTDOWN_COMPLETE == ch->type) | |
629 | goto discard; | |
630 | ||
631 | /* RFC 8.4, 7) If the packet contains a "Stale cookie" ERROR | |
632 | * or a COOKIE ACK the SCTP Packet should be silently | |
633 | * discarded. | |
634 | */ | |
635 | if (SCTP_CID_COOKIE_ACK == ch->type) | |
636 | goto discard; | |
637 | ||
638 | if (SCTP_CID_ERROR == ch->type) { | |
639 | sctp_walk_errors(err, ch) { | |
640 | if (SCTP_ERROR_STALE_COOKIE == err->cause) | |
641 | goto discard; | |
642 | } | |
643 | } | |
644 | ||
645 | ch = (sctp_chunkhdr_t *) ch_end; | |
27a884dc | 646 | } while (ch_end < skb_tail_pointer(skb)); |
1da177e4 LT |
647 | |
648 | return 0; | |
649 | ||
650 | discard: | |
651 | return 1; | |
652 | } | |
653 | ||
654 | /* Insert endpoint into the hash table. */ | |
655 | static void __sctp_hash_endpoint(struct sctp_endpoint *ep) | |
656 | { | |
657 | struct sctp_ep_common **epp; | |
658 | struct sctp_ep_common *epb; | |
659 | struct sctp_hashbucket *head; | |
660 | ||
661 | epb = &ep->base; | |
662 | ||
663 | epb->hashent = sctp_ep_hashfn(epb->bind_addr.port); | |
664 | head = &sctp_ep_hashtable[epb->hashent]; | |
665 | ||
666 | sctp_write_lock(&head->lock); | |
667 | epp = &head->chain; | |
668 | epb->next = *epp; | |
669 | if (epb->next) | |
670 | (*epp)->pprev = &epb->next; | |
671 | *epp = epb; | |
672 | epb->pprev = epp; | |
673 | sctp_write_unlock(&head->lock); | |
674 | } | |
675 | ||
676 | /* Add an endpoint to the hash. Local BH-safe. */ | |
677 | void sctp_hash_endpoint(struct sctp_endpoint *ep) | |
678 | { | |
679 | sctp_local_bh_disable(); | |
680 | __sctp_hash_endpoint(ep); | |
681 | sctp_local_bh_enable(); | |
682 | } | |
683 | ||
684 | /* Remove endpoint from the hash table. */ | |
685 | static void __sctp_unhash_endpoint(struct sctp_endpoint *ep) | |
686 | { | |
687 | struct sctp_hashbucket *head; | |
688 | struct sctp_ep_common *epb; | |
689 | ||
690 | epb = &ep->base; | |
691 | ||
692 | epb->hashent = sctp_ep_hashfn(epb->bind_addr.port); | |
693 | ||
694 | head = &sctp_ep_hashtable[epb->hashent]; | |
695 | ||
696 | sctp_write_lock(&head->lock); | |
697 | ||
698 | if (epb->pprev) { | |
699 | if (epb->next) | |
700 | epb->next->pprev = epb->pprev; | |
701 | *epb->pprev = epb->next; | |
702 | epb->pprev = NULL; | |
703 | } | |
704 | ||
705 | sctp_write_unlock(&head->lock); | |
706 | } | |
707 | ||
708 | /* Remove endpoint from the hash. Local BH-safe. */ | |
709 | void sctp_unhash_endpoint(struct sctp_endpoint *ep) | |
710 | { | |
711 | sctp_local_bh_disable(); | |
712 | __sctp_unhash_endpoint(ep); | |
713 | sctp_local_bh_enable(); | |
714 | } | |
715 | ||
716 | /* Look up an endpoint. */ | |
717 | static struct sctp_endpoint *__sctp_rcv_lookup_endpoint(const union sctp_addr *laddr) | |
718 | { | |
719 | struct sctp_hashbucket *head; | |
720 | struct sctp_ep_common *epb; | |
721 | struct sctp_endpoint *ep; | |
722 | int hash; | |
723 | ||
1c7d1fc1 | 724 | hash = sctp_ep_hashfn(ntohs(laddr->v4.sin_port)); |
1da177e4 LT |
725 | head = &sctp_ep_hashtable[hash]; |
726 | read_lock(&head->lock); | |
727 | for (epb = head->chain; epb; epb = epb->next) { | |
728 | ep = sctp_ep(epb); | |
729 | if (sctp_endpoint_is_match(ep, laddr)) | |
730 | goto hit; | |
731 | } | |
732 | ||
733 | ep = sctp_sk((sctp_get_ctl_sock()))->ep; | |
734 | epb = &ep->base; | |
735 | ||
736 | hit: | |
737 | sctp_endpoint_hold(ep); | |
1da177e4 LT |
738 | read_unlock(&head->lock); |
739 | return ep; | |
740 | } | |
741 | ||
742 | /* Insert association into the hash table. */ | |
743 | static void __sctp_hash_established(struct sctp_association *asoc) | |
744 | { | |
745 | struct sctp_ep_common **epp; | |
746 | struct sctp_ep_common *epb; | |
747 | struct sctp_hashbucket *head; | |
748 | ||
749 | epb = &asoc->base; | |
750 | ||
751 | /* Calculate which chain this entry will belong to. */ | |
752 | epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port, asoc->peer.port); | |
753 | ||
754 | head = &sctp_assoc_hashtable[epb->hashent]; | |
755 | ||
756 | sctp_write_lock(&head->lock); | |
757 | epp = &head->chain; | |
758 | epb->next = *epp; | |
759 | if (epb->next) | |
760 | (*epp)->pprev = &epb->next; | |
761 | *epp = epb; | |
762 | epb->pprev = epp; | |
763 | sctp_write_unlock(&head->lock); | |
764 | } | |
765 | ||
766 | /* Add an association to the hash. Local BH-safe. */ | |
767 | void sctp_hash_established(struct sctp_association *asoc) | |
768 | { | |
de76e695 VY |
769 | if (asoc->temp) |
770 | return; | |
771 | ||
1da177e4 LT |
772 | sctp_local_bh_disable(); |
773 | __sctp_hash_established(asoc); | |
774 | sctp_local_bh_enable(); | |
775 | } | |
776 | ||
777 | /* Remove association from the hash table. */ | |
778 | static void __sctp_unhash_established(struct sctp_association *asoc) | |
779 | { | |
780 | struct sctp_hashbucket *head; | |
781 | struct sctp_ep_common *epb; | |
782 | ||
783 | epb = &asoc->base; | |
784 | ||
785 | epb->hashent = sctp_assoc_hashfn(epb->bind_addr.port, | |
786 | asoc->peer.port); | |
787 | ||
788 | head = &sctp_assoc_hashtable[epb->hashent]; | |
789 | ||
790 | sctp_write_lock(&head->lock); | |
791 | ||
792 | if (epb->pprev) { | |
793 | if (epb->next) | |
794 | epb->next->pprev = epb->pprev; | |
795 | *epb->pprev = epb->next; | |
796 | epb->pprev = NULL; | |
797 | } | |
798 | ||
799 | sctp_write_unlock(&head->lock); | |
800 | } | |
801 | ||
802 | /* Remove association from the hash table. Local BH-safe. */ | |
803 | void sctp_unhash_established(struct sctp_association *asoc) | |
804 | { | |
de76e695 VY |
805 | if (asoc->temp) |
806 | return; | |
807 | ||
1da177e4 LT |
808 | sctp_local_bh_disable(); |
809 | __sctp_unhash_established(asoc); | |
810 | sctp_local_bh_enable(); | |
811 | } | |
812 | ||
813 | /* Look up an association. */ | |
814 | static struct sctp_association *__sctp_lookup_association( | |
815 | const union sctp_addr *local, | |
816 | const union sctp_addr *peer, | |
817 | struct sctp_transport **pt) | |
818 | { | |
819 | struct sctp_hashbucket *head; | |
820 | struct sctp_ep_common *epb; | |
821 | struct sctp_association *asoc; | |
822 | struct sctp_transport *transport; | |
823 | int hash; | |
824 | ||
825 | /* Optimize here for direct hit, only listening connections can | |
826 | * have wildcards anyways. | |
827 | */ | |
e2fccedb | 828 | hash = sctp_assoc_hashfn(ntohs(local->v4.sin_port), ntohs(peer->v4.sin_port)); |
1da177e4 LT |
829 | head = &sctp_assoc_hashtable[hash]; |
830 | read_lock(&head->lock); | |
831 | for (epb = head->chain; epb; epb = epb->next) { | |
832 | asoc = sctp_assoc(epb); | |
833 | transport = sctp_assoc_is_match(asoc, local, peer); | |
834 | if (transport) | |
835 | goto hit; | |
836 | } | |
837 | ||
838 | read_unlock(&head->lock); | |
839 | ||
840 | return NULL; | |
841 | ||
842 | hit: | |
843 | *pt = transport; | |
844 | sctp_association_hold(asoc); | |
1da177e4 LT |
845 | read_unlock(&head->lock); |
846 | return asoc; | |
847 | } | |
848 | ||
849 | /* Look up an association. BH-safe. */ | |
850 | SCTP_STATIC | |
851 | struct sctp_association *sctp_lookup_association(const union sctp_addr *laddr, | |
852 | const union sctp_addr *paddr, | |
853 | struct sctp_transport **transportp) | |
854 | { | |
855 | struct sctp_association *asoc; | |
856 | ||
857 | sctp_local_bh_disable(); | |
858 | asoc = __sctp_lookup_association(laddr, paddr, transportp); | |
859 | sctp_local_bh_enable(); | |
860 | ||
861 | return asoc; | |
862 | } | |
863 | ||
864 | /* Is there an association matching the given local and peer addresses? */ | |
865 | int sctp_has_association(const union sctp_addr *laddr, | |
866 | const union sctp_addr *paddr) | |
867 | { | |
868 | struct sctp_association *asoc; | |
869 | struct sctp_transport *transport; | |
870 | ||
6c7be55c | 871 | if ((asoc = sctp_lookup_association(laddr, paddr, &transport))) { |
1da177e4 LT |
872 | sctp_association_put(asoc); |
873 | return 1; | |
874 | } | |
875 | ||
876 | return 0; | |
877 | } | |
878 | ||
879 | /* | |
880 | * SCTP Implementors Guide, 2.18 Handling of address | |
881 | * parameters within the INIT or INIT-ACK. | |
882 | * | |
883 | * D) When searching for a matching TCB upon reception of an INIT | |
884 | * or INIT-ACK chunk the receiver SHOULD use not only the | |
885 | * source address of the packet (containing the INIT or | |
886 | * INIT-ACK) but the receiver SHOULD also use all valid | |
887 | * address parameters contained within the chunk. | |
888 | * | |
889 | * 2.18.3 Solution description | |
890 | * | |
891 | * This new text clearly specifies to an implementor the need | |
892 | * to look within the INIT or INIT-ACK. Any implementation that | |
893 | * does not do this, may not be able to establish associations | |
894 | * in certain circumstances. | |
895 | * | |
896 | */ | |
897 | static struct sctp_association *__sctp_rcv_init_lookup(struct sk_buff *skb, | |
898 | const union sctp_addr *laddr, struct sctp_transport **transportp) | |
899 | { | |
900 | struct sctp_association *asoc; | |
901 | union sctp_addr addr; | |
902 | union sctp_addr *paddr = &addr; | |
2c0fd387 | 903 | struct sctphdr *sh = sctp_hdr(skb); |
1da177e4 LT |
904 | sctp_chunkhdr_t *ch; |
905 | union sctp_params params; | |
906 | sctp_init_chunk_t *init; | |
907 | struct sctp_transport *transport; | |
908 | struct sctp_af *af; | |
909 | ||
910 | ch = (sctp_chunkhdr_t *) skb->data; | |
911 | ||
912 | /* If this is INIT/INIT-ACK look inside the chunk too. */ | |
913 | switch (ch->type) { | |
914 | case SCTP_CID_INIT: | |
915 | case SCTP_CID_INIT_ACK: | |
916 | break; | |
917 | default: | |
918 | return NULL; | |
919 | } | |
920 | ||
921 | /* The code below will attempt to walk the chunk and extract | |
922 | * parameter information. Before we do that, we need to verify | |
923 | * that the chunk length doesn't cause overflow. Otherwise, we'll | |
924 | * walk off the end. | |
925 | */ | |
926 | if (WORD_ROUND(ntohs(ch->length)) > skb->len) | |
927 | return NULL; | |
928 | ||
929 | /* | |
930 | * This code will NOT touch anything inside the chunk--it is | |
931 | * strictly READ-ONLY. | |
932 | * | |
933 | * RFC 2960 3 SCTP packet Format | |
934 | * | |
935 | * Multiple chunks can be bundled into one SCTP packet up to | |
936 | * the MTU size, except for the INIT, INIT ACK, and SHUTDOWN | |
937 | * COMPLETE chunks. These chunks MUST NOT be bundled with any | |
938 | * other chunk in a packet. See Section 6.10 for more details | |
939 | * on chunk bundling. | |
940 | */ | |
941 | ||
942 | /* Find the start of the TLVs and the end of the chunk. This is | |
943 | * the region we search for address parameters. | |
944 | */ | |
945 | init = (sctp_init_chunk_t *)skb->data; | |
946 | ||
947 | /* Walk the parameters looking for embedded addresses. */ | |
948 | sctp_walk_params(params, init, init_hdr.params) { | |
949 | ||
950 | /* Note: Ignoring hostname addresses. */ | |
951 | af = sctp_get_af_specific(param_type2af(params.p->type)); | |
952 | if (!af) | |
953 | continue; | |
954 | ||
dd86d136 | 955 | af->from_addr_param(paddr, params.addr, sh->source, 0); |
1da177e4 | 956 | |
dd86d136 | 957 | asoc = __sctp_lookup_association(laddr, paddr, &transport); |
1da177e4 LT |
958 | if (asoc) |
959 | return asoc; | |
960 | } | |
961 | ||
962 | return NULL; | |
963 | } | |
964 | ||
965 | /* Lookup an association for an inbound skb. */ | |
966 | static struct sctp_association *__sctp_rcv_lookup(struct sk_buff *skb, | |
967 | const union sctp_addr *paddr, | |
968 | const union sctp_addr *laddr, | |
969 | struct sctp_transport **transportp) | |
970 | { | |
971 | struct sctp_association *asoc; | |
972 | ||
973 | asoc = __sctp_lookup_association(laddr, paddr, transportp); | |
974 | ||
975 | /* Further lookup for INIT/INIT-ACK packets. | |
976 | * SCTP Implementors Guide, 2.18 Handling of address | |
977 | * parameters within the INIT or INIT-ACK. | |
978 | */ | |
979 | if (!asoc) | |
980 | asoc = __sctp_rcv_init_lookup(skb, laddr, transportp); | |
981 | ||
982 | return asoc; | |
983 | } |