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1 | /* SCTP kernel implementation | |
2 | * Copyright (c) 1999-2000 Cisco, Inc. | |
3 | * Copyright (c) 1999-2001 Motorola, Inc. | |
4 | * Copyright (c) 2001-2002 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 implementation | |
10 | * | |
11 | * This abstraction represents an SCTP endpoint. | |
12 | * | |
13 | * The SCTP 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 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, see | |
27 | * <http://www.gnu.org/licenses/>. | |
28 | * | |
29 | * Please send any bug reports or fixes you make to the | |
30 | * email address(es): | |
31 | * lksctp developers <linux-sctp@vger.kernel.org> | |
32 | * | |
33 | * Written or modified by: | |
34 | * La Monte H.P. Yarroll <piggy@acm.org> | |
35 | * Karl Knutson <karl@athena.chicago.il.us> | |
36 | * Jon Grimm <jgrimm@austin.ibm.com> | |
37 | * Daisy Chang <daisyc@us.ibm.com> | |
38 | * Dajiang Zhang <dajiang.zhang@nokia.com> | |
39 | */ | |
40 | ||
41 | #include <linux/types.h> | |
42 | #include <linux/slab.h> | |
43 | #include <linux/in.h> | |
44 | #include <linux/random.h> /* get_random_bytes() */ | |
45 | #include <linux/crypto.h> | |
46 | #include <net/sock.h> | |
47 | #include <net/ipv6.h> | |
48 | #include <net/sctp/sctp.h> | |
49 | #include <net/sctp/sm.h> | |
50 | ||
51 | /* Forward declarations for internal helpers. */ | |
52 | static void sctp_endpoint_bh_rcv(struct work_struct *work); | |
53 | ||
54 | /* | |
55 | * Initialize the base fields of the endpoint structure. | |
56 | */ | |
57 | static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep, | |
58 | struct sock *sk, | |
59 | gfp_t gfp) | |
60 | { | |
61 | struct net *net = sock_net(sk); | |
62 | struct sctp_hmac_algo_param *auth_hmacs = NULL; | |
63 | struct sctp_chunks_param *auth_chunks = NULL; | |
64 | struct sctp_shared_key *null_key; | |
65 | int err; | |
66 | ||
67 | ep->digest = kzalloc(SCTP_SIGNATURE_SIZE, gfp); | |
68 | if (!ep->digest) | |
69 | return NULL; | |
70 | ||
71 | if (net->sctp.auth_enable) { | |
72 | /* Allocate space for HMACS and CHUNKS authentication | |
73 | * variables. There are arrays that we encode directly | |
74 | * into parameters to make the rest of the operations easier. | |
75 | */ | |
76 | auth_hmacs = kzalloc(sizeof(sctp_hmac_algo_param_t) + | |
77 | sizeof(__u16) * SCTP_AUTH_NUM_HMACS, gfp); | |
78 | if (!auth_hmacs) | |
79 | goto nomem; | |
80 | ||
81 | auth_chunks = kzalloc(sizeof(sctp_chunks_param_t) + | |
82 | SCTP_NUM_CHUNK_TYPES, gfp); | |
83 | if (!auth_chunks) | |
84 | goto nomem; | |
85 | ||
86 | /* Initialize the HMACS parameter. | |
87 | * SCTP-AUTH: Section 3.3 | |
88 | * Every endpoint supporting SCTP chunk authentication MUST | |
89 | * support the HMAC based on the SHA-1 algorithm. | |
90 | */ | |
91 | auth_hmacs->param_hdr.type = SCTP_PARAM_HMAC_ALGO; | |
92 | auth_hmacs->param_hdr.length = | |
93 | htons(sizeof(sctp_paramhdr_t) + 2); | |
94 | auth_hmacs->hmac_ids[0] = htons(SCTP_AUTH_HMAC_ID_SHA1); | |
95 | ||
96 | /* Initialize the CHUNKS parameter */ | |
97 | auth_chunks->param_hdr.type = SCTP_PARAM_CHUNKS; | |
98 | auth_chunks->param_hdr.length = htons(sizeof(sctp_paramhdr_t)); | |
99 | ||
100 | /* If the Add-IP functionality is enabled, we must | |
101 | * authenticate, ASCONF and ASCONF-ACK chunks | |
102 | */ | |
103 | if (net->sctp.addip_enable) { | |
104 | auth_chunks->chunks[0] = SCTP_CID_ASCONF; | |
105 | auth_chunks->chunks[1] = SCTP_CID_ASCONF_ACK; | |
106 | auth_chunks->param_hdr.length = | |
107 | htons(sizeof(sctp_paramhdr_t) + 2); | |
108 | } | |
109 | } | |
110 | ||
111 | /* Initialize the base structure. */ | |
112 | /* What type of endpoint are we? */ | |
113 | ep->base.type = SCTP_EP_TYPE_SOCKET; | |
114 | ||
115 | /* Initialize the basic object fields. */ | |
116 | atomic_set(&ep->base.refcnt, 1); | |
117 | ep->base.dead = false; | |
118 | ||
119 | /* Create an input queue. */ | |
120 | sctp_inq_init(&ep->base.inqueue); | |
121 | ||
122 | /* Set its top-half handler */ | |
123 | sctp_inq_set_th_handler(&ep->base.inqueue, sctp_endpoint_bh_rcv); | |
124 | ||
125 | /* Initialize the bind addr area */ | |
126 | sctp_bind_addr_init(&ep->base.bind_addr, 0); | |
127 | ||
128 | /* Remember who we are attached to. */ | |
129 | ep->base.sk = sk; | |
130 | sock_hold(ep->base.sk); | |
131 | ||
132 | /* Create the lists of associations. */ | |
133 | INIT_LIST_HEAD(&ep->asocs); | |
134 | ||
135 | /* Use SCTP specific send buffer space queues. */ | |
136 | ep->sndbuf_policy = net->sctp.sndbuf_policy; | |
137 | ||
138 | sk->sk_data_ready = sctp_data_ready; | |
139 | sk->sk_write_space = sctp_write_space; | |
140 | sock_set_flag(sk, SOCK_USE_WRITE_QUEUE); | |
141 | ||
142 | /* Get the receive buffer policy for this endpoint */ | |
143 | ep->rcvbuf_policy = net->sctp.rcvbuf_policy; | |
144 | ||
145 | /* Initialize the secret key used with cookie. */ | |
146 | get_random_bytes(ep->secret_key, sizeof(ep->secret_key)); | |
147 | ||
148 | /* SCTP-AUTH extensions*/ | |
149 | INIT_LIST_HEAD(&ep->endpoint_shared_keys); | |
150 | null_key = sctp_auth_shkey_create(0, gfp); | |
151 | if (!null_key) | |
152 | goto nomem; | |
153 | ||
154 | list_add(&null_key->key_list, &ep->endpoint_shared_keys); | |
155 | ||
156 | /* Allocate and initialize transorms arrays for supported HMACs. */ | |
157 | err = sctp_auth_init_hmacs(ep, gfp); | |
158 | if (err) | |
159 | goto nomem_hmacs; | |
160 | ||
161 | /* Add the null key to the endpoint shared keys list and | |
162 | * set the hmcas and chunks pointers. | |
163 | */ | |
164 | ep->auth_hmacs_list = auth_hmacs; | |
165 | ep->auth_chunk_list = auth_chunks; | |
166 | ||
167 | return ep; | |
168 | ||
169 | nomem_hmacs: | |
170 | sctp_auth_destroy_keys(&ep->endpoint_shared_keys); | |
171 | nomem: | |
172 | /* Free all allocations */ | |
173 | kfree(auth_hmacs); | |
174 | kfree(auth_chunks); | |
175 | kfree(ep->digest); | |
176 | return NULL; | |
177 | ||
178 | } | |
179 | ||
180 | /* Create a sctp_endpoint with all that boring stuff initialized. | |
181 | * Returns NULL if there isn't enough memory. | |
182 | */ | |
183 | struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp) | |
184 | { | |
185 | struct sctp_endpoint *ep; | |
186 | ||
187 | /* Build a local endpoint. */ | |
188 | ep = kzalloc(sizeof(*ep), gfp); | |
189 | if (!ep) | |
190 | goto fail; | |
191 | ||
192 | if (!sctp_endpoint_init(ep, sk, gfp)) | |
193 | goto fail_init; | |
194 | ||
195 | SCTP_DBG_OBJCNT_INC(ep); | |
196 | return ep; | |
197 | ||
198 | fail_init: | |
199 | kfree(ep); | |
200 | fail: | |
201 | return NULL; | |
202 | } | |
203 | ||
204 | /* Add an association to an endpoint. */ | |
205 | void sctp_endpoint_add_asoc(struct sctp_endpoint *ep, | |
206 | struct sctp_association *asoc) | |
207 | { | |
208 | struct sock *sk = ep->base.sk; | |
209 | ||
210 | /* If this is a temporary association, don't bother | |
211 | * since we'll be removing it shortly and don't | |
212 | * want anyone to find it anyway. | |
213 | */ | |
214 | if (asoc->temp) | |
215 | return; | |
216 | ||
217 | /* Now just add it to our list of asocs */ | |
218 | list_add_tail(&asoc->asocs, &ep->asocs); | |
219 | ||
220 | /* Increment the backlog value for a TCP-style listening socket. */ | |
221 | if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING)) | |
222 | sk->sk_ack_backlog++; | |
223 | } | |
224 | ||
225 | /* Free the endpoint structure. Delay cleanup until | |
226 | * all users have released their reference count on this structure. | |
227 | */ | |
228 | void sctp_endpoint_free(struct sctp_endpoint *ep) | |
229 | { | |
230 | ep->base.dead = true; | |
231 | ||
232 | ep->base.sk->sk_state = SCTP_SS_CLOSED; | |
233 | ||
234 | /* Unlink this endpoint, so we can't find it again! */ | |
235 | sctp_unhash_endpoint(ep); | |
236 | ||
237 | sctp_endpoint_put(ep); | |
238 | } | |
239 | ||
240 | /* Final destructor for endpoint. */ | |
241 | static void sctp_endpoint_destroy(struct sctp_endpoint *ep) | |
242 | { | |
243 | struct sock *sk; | |
244 | ||
245 | if (unlikely(!ep->base.dead)) { | |
246 | WARN(1, "Attempt to destroy undead endpoint %p!\n", ep); | |
247 | return; | |
248 | } | |
249 | ||
250 | /* Free the digest buffer */ | |
251 | kfree(ep->digest); | |
252 | ||
253 | /* SCTP-AUTH: Free up AUTH releated data such as shared keys | |
254 | * chunks and hmacs arrays that were allocated | |
255 | */ | |
256 | sctp_auth_destroy_keys(&ep->endpoint_shared_keys); | |
257 | kfree(ep->auth_hmacs_list); | |
258 | kfree(ep->auth_chunk_list); | |
259 | ||
260 | /* AUTH - Free any allocated HMAC transform containers */ | |
261 | sctp_auth_destroy_hmacs(ep->auth_hmacs); | |
262 | ||
263 | /* Cleanup. */ | |
264 | sctp_inq_free(&ep->base.inqueue); | |
265 | sctp_bind_addr_free(&ep->base.bind_addr); | |
266 | ||
267 | memset(ep->secret_key, 0, sizeof(ep->secret_key)); | |
268 | ||
269 | /* Give up our hold on the sock. */ | |
270 | sk = ep->base.sk; | |
271 | if (sk != NULL) { | |
272 | /* Remove and free the port */ | |
273 | if (sctp_sk(sk)->bind_hash) | |
274 | sctp_put_port(sk); | |
275 | ||
276 | sock_put(sk); | |
277 | } | |
278 | ||
279 | kfree(ep); | |
280 | SCTP_DBG_OBJCNT_DEC(ep); | |
281 | } | |
282 | ||
283 | /* Hold a reference to an endpoint. */ | |
284 | void sctp_endpoint_hold(struct sctp_endpoint *ep) | |
285 | { | |
286 | atomic_inc(&ep->base.refcnt); | |
287 | } | |
288 | ||
289 | /* Release a reference to an endpoint and clean up if there are | |
290 | * no more references. | |
291 | */ | |
292 | void sctp_endpoint_put(struct sctp_endpoint *ep) | |
293 | { | |
294 | if (atomic_dec_and_test(&ep->base.refcnt)) | |
295 | sctp_endpoint_destroy(ep); | |
296 | } | |
297 | ||
298 | /* Is this the endpoint we are looking for? */ | |
299 | struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep, | |
300 | struct net *net, | |
301 | const union sctp_addr *laddr) | |
302 | { | |
303 | struct sctp_endpoint *retval = NULL; | |
304 | ||
305 | if ((htons(ep->base.bind_addr.port) == laddr->v4.sin_port) && | |
306 | net_eq(sock_net(ep->base.sk), net)) { | |
307 | if (sctp_bind_addr_match(&ep->base.bind_addr, laddr, | |
308 | sctp_sk(ep->base.sk))) | |
309 | retval = ep; | |
310 | } | |
311 | ||
312 | return retval; | |
313 | } | |
314 | ||
315 | /* Find the association that goes with this chunk. | |
316 | * We do a linear search of the associations for this endpoint. | |
317 | * We return the matching transport address too. | |
318 | */ | |
319 | static struct sctp_association *__sctp_endpoint_lookup_assoc( | |
320 | const struct sctp_endpoint *ep, | |
321 | const union sctp_addr *paddr, | |
322 | struct sctp_transport **transport) | |
323 | { | |
324 | struct sctp_association *asoc = NULL; | |
325 | struct sctp_association *tmp; | |
326 | struct sctp_transport *t = NULL; | |
327 | struct sctp_hashbucket *head; | |
328 | struct sctp_ep_common *epb; | |
329 | int hash; | |
330 | int rport; | |
331 | ||
332 | *transport = NULL; | |
333 | ||
334 | /* If the local port is not set, there can't be any associations | |
335 | * on this endpoint. | |
336 | */ | |
337 | if (!ep->base.bind_addr.port) | |
338 | goto out; | |
339 | ||
340 | rport = ntohs(paddr->v4.sin_port); | |
341 | ||
342 | hash = sctp_assoc_hashfn(sock_net(ep->base.sk), ep->base.bind_addr.port, | |
343 | rport); | |
344 | head = &sctp_assoc_hashtable[hash]; | |
345 | read_lock(&head->lock); | |
346 | sctp_for_each_hentry(epb, &head->chain) { | |
347 | tmp = sctp_assoc(epb); | |
348 | if (tmp->ep != ep || rport != tmp->peer.port) | |
349 | continue; | |
350 | ||
351 | t = sctp_assoc_lookup_paddr(tmp, paddr); | |
352 | if (t) { | |
353 | asoc = tmp; | |
354 | *transport = t; | |
355 | break; | |
356 | } | |
357 | } | |
358 | read_unlock(&head->lock); | |
359 | out: | |
360 | return asoc; | |
361 | } | |
362 | ||
363 | /* Lookup association on an endpoint based on a peer address. BH-safe. */ | |
364 | struct sctp_association *sctp_endpoint_lookup_assoc( | |
365 | const struct sctp_endpoint *ep, | |
366 | const union sctp_addr *paddr, | |
367 | struct sctp_transport **transport) | |
368 | { | |
369 | struct sctp_association *asoc; | |
370 | ||
371 | local_bh_disable(); | |
372 | asoc = __sctp_endpoint_lookup_assoc(ep, paddr, transport); | |
373 | local_bh_enable(); | |
374 | ||
375 | return asoc; | |
376 | } | |
377 | ||
378 | /* Look for any peeled off association from the endpoint that matches the | |
379 | * given peer address. | |
380 | */ | |
381 | int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep, | |
382 | const union sctp_addr *paddr) | |
383 | { | |
384 | struct sctp_sockaddr_entry *addr; | |
385 | struct sctp_bind_addr *bp; | |
386 | struct net *net = sock_net(ep->base.sk); | |
387 | ||
388 | bp = &ep->base.bind_addr; | |
389 | /* This function is called with the socket lock held, | |
390 | * so the address_list can not change. | |
391 | */ | |
392 | list_for_each_entry(addr, &bp->address_list, list) { | |
393 | if (sctp_has_association(net, &addr->a, paddr)) | |
394 | return 1; | |
395 | } | |
396 | ||
397 | return 0; | |
398 | } | |
399 | ||
400 | /* Do delayed input processing. This is scheduled by sctp_rcv(). | |
401 | * This may be called on BH or task time. | |
402 | */ | |
403 | static void sctp_endpoint_bh_rcv(struct work_struct *work) | |
404 | { | |
405 | struct sctp_endpoint *ep = | |
406 | container_of(work, struct sctp_endpoint, | |
407 | base.inqueue.immediate); | |
408 | struct sctp_association *asoc; | |
409 | struct sock *sk; | |
410 | struct net *net; | |
411 | struct sctp_transport *transport; | |
412 | struct sctp_chunk *chunk; | |
413 | struct sctp_inq *inqueue; | |
414 | sctp_subtype_t subtype; | |
415 | sctp_state_t state; | |
416 | int error = 0; | |
417 | int first_time = 1; /* is this the first time through the loop */ | |
418 | ||
419 | if (ep->base.dead) | |
420 | return; | |
421 | ||
422 | asoc = NULL; | |
423 | inqueue = &ep->base.inqueue; | |
424 | sk = ep->base.sk; | |
425 | net = sock_net(sk); | |
426 | ||
427 | while (NULL != (chunk = sctp_inq_pop(inqueue))) { | |
428 | subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type); | |
429 | ||
430 | /* If the first chunk in the packet is AUTH, do special | |
431 | * processing specified in Section 6.3 of SCTP-AUTH spec | |
432 | */ | |
433 | if (first_time && (subtype.chunk == SCTP_CID_AUTH)) { | |
434 | struct sctp_chunkhdr *next_hdr; | |
435 | ||
436 | next_hdr = sctp_inq_peek(inqueue); | |
437 | if (!next_hdr) | |
438 | goto normal; | |
439 | ||
440 | /* If the next chunk is COOKIE-ECHO, skip the AUTH | |
441 | * chunk while saving a pointer to it so we can do | |
442 | * Authentication later (during cookie-echo | |
443 | * processing). | |
444 | */ | |
445 | if (next_hdr->type == SCTP_CID_COOKIE_ECHO) { | |
446 | chunk->auth_chunk = skb_clone(chunk->skb, | |
447 | GFP_ATOMIC); | |
448 | chunk->auth = 1; | |
449 | continue; | |
450 | } | |
451 | } | |
452 | normal: | |
453 | /* We might have grown an association since last we | |
454 | * looked, so try again. | |
455 | * | |
456 | * This happens when we've just processed our | |
457 | * COOKIE-ECHO chunk. | |
458 | */ | |
459 | if (NULL == chunk->asoc) { | |
460 | asoc = sctp_endpoint_lookup_assoc(ep, | |
461 | sctp_source(chunk), | |
462 | &transport); | |
463 | chunk->asoc = asoc; | |
464 | chunk->transport = transport; | |
465 | } | |
466 | ||
467 | state = asoc ? asoc->state : SCTP_STATE_CLOSED; | |
468 | if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth) | |
469 | continue; | |
470 | ||
471 | /* Remember where the last DATA chunk came from so we | |
472 | * know where to send the SACK. | |
473 | */ | |
474 | if (asoc && sctp_chunk_is_data(chunk)) | |
475 | asoc->peer.last_data_from = chunk->transport; | |
476 | else { | |
477 | SCTP_INC_STATS(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS); | |
478 | if (asoc) | |
479 | asoc->stats.ictrlchunks++; | |
480 | } | |
481 | ||
482 | if (chunk->transport) | |
483 | chunk->transport->last_time_heard = jiffies; | |
484 | ||
485 | error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state, | |
486 | ep, asoc, chunk, GFP_ATOMIC); | |
487 | ||
488 | if (error && chunk) | |
489 | chunk->pdiscard = 1; | |
490 | ||
491 | /* Check to see if the endpoint is freed in response to | |
492 | * the incoming chunk. If so, get out of the while loop. | |
493 | */ | |
494 | if (!sctp_sk(sk)->ep) | |
495 | break; | |
496 | ||
497 | if (first_time) | |
498 | first_time = 0; | |
499 | } | |
500 | } |