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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 <net/sock.h>
46 #include <net/ipv6.h>
47 #include <net/sctp/sctp.h>
48 #include <net/sctp/sm.h>
49
50 /* Forward declarations for internal helpers. */
51 static void sctp_endpoint_bh_rcv(struct work_struct *work);
52
53 /*
54 * Initialize the base fields of the endpoint structure.
55 */
56 static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep,
57 struct sock *sk,
58 gfp_t gfp)
59 {
60 struct net *net = sock_net(sk);
61 struct sctp_hmac_algo_param *auth_hmacs = NULL;
62 struct sctp_chunks_param *auth_chunks = NULL;
63 struct sctp_shared_key *null_key;
64 int err;
65
66 ep->digest = kzalloc(SCTP_SIGNATURE_SIZE, gfp);
67 if (!ep->digest)
68 return NULL;
69
70 ep->auth_enable = net->sctp.auth_enable;
71 if (ep->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 ep->prsctp_enable = net->sctp.prsctp_enable;
167 ep->reconf_enable = net->sctp.reconf_enable;
168
169 return ep;
170
171 nomem_hmacs:
172 sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
173 nomem:
174 /* Free all allocations */
175 kfree(auth_hmacs);
176 kfree(auth_chunks);
177 kfree(ep->digest);
178 return NULL;
179
180 }
181
182 /* Create a sctp_endpoint with all that boring stuff initialized.
183 * Returns NULL if there isn't enough memory.
184 */
185 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp)
186 {
187 struct sctp_endpoint *ep;
188
189 /* Build a local endpoint. */
190 ep = kzalloc(sizeof(*ep), gfp);
191 if (!ep)
192 goto fail;
193
194 if (!sctp_endpoint_init(ep, sk, gfp))
195 goto fail_init;
196
197 SCTP_DBG_OBJCNT_INC(ep);
198 return ep;
199
200 fail_init:
201 kfree(ep);
202 fail:
203 return NULL;
204 }
205
206 /* Add an association to an endpoint. */
207 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep,
208 struct sctp_association *asoc)
209 {
210 struct sock *sk = ep->base.sk;
211
212 /* If this is a temporary association, don't bother
213 * since we'll be removing it shortly and don't
214 * want anyone to find it anyway.
215 */
216 if (asoc->temp)
217 return;
218
219 /* Now just add it to our list of asocs */
220 list_add_tail(&asoc->asocs, &ep->asocs);
221
222 /* Increment the backlog value for a TCP-style listening socket. */
223 if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
224 sk->sk_ack_backlog++;
225 }
226
227 /* Free the endpoint structure. Delay cleanup until
228 * all users have released their reference count on this structure.
229 */
230 void sctp_endpoint_free(struct sctp_endpoint *ep)
231 {
232 ep->base.dead = true;
233
234 ep->base.sk->sk_state = SCTP_SS_CLOSED;
235
236 /* Unlink this endpoint, so we can't find it again! */
237 sctp_unhash_endpoint(ep);
238
239 sctp_endpoint_put(ep);
240 }
241
242 /* Final destructor for endpoint. */
243 static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
244 {
245 struct sock *sk;
246
247 if (unlikely(!ep->base.dead)) {
248 WARN(1, "Attempt to destroy undead endpoint %p!\n", ep);
249 return;
250 }
251
252 /* Free the digest buffer */
253 kfree(ep->digest);
254
255 /* SCTP-AUTH: Free up AUTH releated data such as shared keys
256 * chunks and hmacs arrays that were allocated
257 */
258 sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
259 kfree(ep->auth_hmacs_list);
260 kfree(ep->auth_chunk_list);
261
262 /* AUTH - Free any allocated HMAC transform containers */
263 sctp_auth_destroy_hmacs(ep->auth_hmacs);
264
265 /* Cleanup. */
266 sctp_inq_free(&ep->base.inqueue);
267 sctp_bind_addr_free(&ep->base.bind_addr);
268
269 memset(ep->secret_key, 0, sizeof(ep->secret_key));
270
271 /* Give up our hold on the sock. */
272 sk = ep->base.sk;
273 if (sk != NULL) {
274 /* Remove and free the port */
275 if (sctp_sk(sk)->bind_hash)
276 sctp_put_port(sk);
277
278 sctp_sk(sk)->ep = NULL;
279 sock_put(sk);
280 }
281
282 kfree(ep);
283 SCTP_DBG_OBJCNT_DEC(ep);
284 }
285
286 /* Hold a reference to an endpoint. */
287 void sctp_endpoint_hold(struct sctp_endpoint *ep)
288 {
289 atomic_inc(&ep->base.refcnt);
290 }
291
292 /* Release a reference to an endpoint and clean up if there are
293 * no more references.
294 */
295 void sctp_endpoint_put(struct sctp_endpoint *ep)
296 {
297 if (atomic_dec_and_test(&ep->base.refcnt))
298 sctp_endpoint_destroy(ep);
299 }
300
301 /* Is this the endpoint we are looking for? */
302 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
303 struct net *net,
304 const union sctp_addr *laddr)
305 {
306 struct sctp_endpoint *retval = NULL;
307
308 if ((htons(ep->base.bind_addr.port) == laddr->v4.sin_port) &&
309 net_eq(sock_net(ep->base.sk), net)) {
310 if (sctp_bind_addr_match(&ep->base.bind_addr, laddr,
311 sctp_sk(ep->base.sk)))
312 retval = ep;
313 }
314
315 return retval;
316 }
317
318 /* Find the association that goes with this chunk.
319 * We lookup the transport from hashtable at first, then get association
320 * through t->assoc.
321 */
322 struct sctp_association *sctp_endpoint_lookup_assoc(
323 const struct sctp_endpoint *ep,
324 const union sctp_addr *paddr,
325 struct sctp_transport **transport)
326 {
327 struct sctp_association *asoc = NULL;
328 struct sctp_transport *t;
329
330 *transport = NULL;
331
332 /* If the local port is not set, there can't be any associations
333 * on this endpoint.
334 */
335 if (!ep->base.bind_addr.port)
336 return NULL;
337
338 rcu_read_lock();
339 t = sctp_epaddr_lookup_transport(ep, paddr);
340 if (!t)
341 goto out;
342
343 *transport = t;
344 asoc = t->asoc;
345 out:
346 rcu_read_unlock();
347 return asoc;
348 }
349
350 /* Look for any peeled off association from the endpoint that matches the
351 * given peer address.
352 */
353 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
354 const union sctp_addr *paddr)
355 {
356 struct sctp_sockaddr_entry *addr;
357 struct sctp_bind_addr *bp;
358 struct net *net = sock_net(ep->base.sk);
359
360 bp = &ep->base.bind_addr;
361 /* This function is called with the socket lock held,
362 * so the address_list can not change.
363 */
364 list_for_each_entry(addr, &bp->address_list, list) {
365 if (sctp_has_association(net, &addr->a, paddr))
366 return 1;
367 }
368
369 return 0;
370 }
371
372 /* Do delayed input processing. This is scheduled by sctp_rcv().
373 * This may be called on BH or task time.
374 */
375 static void sctp_endpoint_bh_rcv(struct work_struct *work)
376 {
377 struct sctp_endpoint *ep =
378 container_of(work, struct sctp_endpoint,
379 base.inqueue.immediate);
380 struct sctp_association *asoc;
381 struct sock *sk;
382 struct net *net;
383 struct sctp_transport *transport;
384 struct sctp_chunk *chunk;
385 struct sctp_inq *inqueue;
386 sctp_subtype_t subtype;
387 sctp_state_t state;
388 int error = 0;
389 int first_time = 1; /* is this the first time through the loop */
390
391 if (ep->base.dead)
392 return;
393
394 asoc = NULL;
395 inqueue = &ep->base.inqueue;
396 sk = ep->base.sk;
397 net = sock_net(sk);
398
399 while (NULL != (chunk = sctp_inq_pop(inqueue))) {
400 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
401
402 /* If the first chunk in the packet is AUTH, do special
403 * processing specified in Section 6.3 of SCTP-AUTH spec
404 */
405 if (first_time && (subtype.chunk == SCTP_CID_AUTH)) {
406 struct sctp_chunkhdr *next_hdr;
407
408 next_hdr = sctp_inq_peek(inqueue);
409 if (!next_hdr)
410 goto normal;
411
412 /* If the next chunk is COOKIE-ECHO, skip the AUTH
413 * chunk while saving a pointer to it so we can do
414 * Authentication later (during cookie-echo
415 * processing).
416 */
417 if (next_hdr->type == SCTP_CID_COOKIE_ECHO) {
418 chunk->auth_chunk = skb_clone(chunk->skb,
419 GFP_ATOMIC);
420 chunk->auth = 1;
421 continue;
422 }
423 }
424 normal:
425 /* We might have grown an association since last we
426 * looked, so try again.
427 *
428 * This happens when we've just processed our
429 * COOKIE-ECHO chunk.
430 */
431 if (NULL == chunk->asoc) {
432 asoc = sctp_endpoint_lookup_assoc(ep,
433 sctp_source(chunk),
434 &transport);
435 chunk->asoc = asoc;
436 chunk->transport = transport;
437 }
438
439 state = asoc ? asoc->state : SCTP_STATE_CLOSED;
440 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
441 continue;
442
443 /* Remember where the last DATA chunk came from so we
444 * know where to send the SACK.
445 */
446 if (asoc && sctp_chunk_is_data(chunk))
447 asoc->peer.last_data_from = chunk->transport;
448 else {
449 SCTP_INC_STATS(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS);
450 if (asoc)
451 asoc->stats.ictrlchunks++;
452 }
453
454 if (chunk->transport)
455 chunk->transport->last_time_heard = ktime_get();
456
457 error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state,
458 ep, asoc, chunk, GFP_ATOMIC);
459
460 if (error && chunk)
461 chunk->pdiscard = 1;
462
463 /* Check to see if the endpoint is freed in response to
464 * the incoming chunk. If so, get out of the while loop.
465 */
466 if (!sctp_sk(sk)->ep)
467 break;
468
469 if (first_time)
470 first_time = 0;
471 }
472 }