xref: /linux/net/sctp/endpointola.c (revision 4413e16d9d21673bb5048a2e542f1aaa00015c2e)
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, 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  *    Jon Grimm <jgrimm@austin.ibm.com>
41  *    Daisy Chang <daisyc@us.ibm.com>
42  *    Dajiang Zhang <dajiang.zhang@nokia.com>
43  *
44  * Any bugs reported given to us we will try to fix... any fixes shared will
45  * be incorporated into the next SCTP release.
46  */
47 
48 #include <linux/types.h>
49 #include <linux/slab.h>
50 #include <linux/in.h>
51 #include <linux/random.h>	/* get_random_bytes() */
52 #include <linux/crypto.h>
53 #include <net/sock.h>
54 #include <net/ipv6.h>
55 #include <net/sctp/sctp.h>
56 #include <net/sctp/sm.h>
57 
58 /* Forward declarations for internal helpers. */
59 static void sctp_endpoint_bh_rcv(struct work_struct *work);
60 
61 /*
62  * Initialize the base fields of the endpoint structure.
63  */
64 static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep,
65 						struct sock *sk,
66 						gfp_t gfp)
67 {
68 	struct sctp_hmac_algo_param *auth_hmacs = NULL;
69 	struct sctp_chunks_param *auth_chunks = NULL;
70 	struct sctp_shared_key *null_key;
71 	int err;
72 
73 	ep->digest = kzalloc(SCTP_SIGNATURE_SIZE, gfp);
74 	if (!ep->digest)
75 		return NULL;
76 
77 	if (sctp_auth_enable) {
78 		/* Allocate space for HMACS and CHUNKS authentication
79 		 * variables.  There are arrays that we encode directly
80 		 * into parameters to make the rest of the operations easier.
81 		 */
82 		auth_hmacs = kzalloc(sizeof(sctp_hmac_algo_param_t) +
83 				sizeof(__u16) * SCTP_AUTH_NUM_HMACS, gfp);
84 		if (!auth_hmacs)
85 			goto nomem;
86 
87 		auth_chunks = kzalloc(sizeof(sctp_chunks_param_t) +
88 					SCTP_NUM_CHUNK_TYPES, gfp);
89 		if (!auth_chunks)
90 			goto nomem;
91 
92 		/* Initialize the HMACS parameter.
93 		 * SCTP-AUTH: Section 3.3
94 		 *    Every endpoint supporting SCTP chunk authentication MUST
95 		 *    support the HMAC based on the SHA-1 algorithm.
96 		 */
97 		auth_hmacs->param_hdr.type = SCTP_PARAM_HMAC_ALGO;
98 		auth_hmacs->param_hdr.length =
99 					htons(sizeof(sctp_paramhdr_t) + 2);
100 		auth_hmacs->hmac_ids[0] = htons(SCTP_AUTH_HMAC_ID_SHA1);
101 
102 		/* Initialize the CHUNKS parameter */
103 		auth_chunks->param_hdr.type = SCTP_PARAM_CHUNKS;
104 		auth_chunks->param_hdr.length = htons(sizeof(sctp_paramhdr_t));
105 
106 		/* If the Add-IP functionality is enabled, we must
107 		 * authenticate, ASCONF and ASCONF-ACK chunks
108 		 */
109 		if (sctp_addip_enable) {
110 			auth_chunks->chunks[0] = SCTP_CID_ASCONF;
111 			auth_chunks->chunks[1] = SCTP_CID_ASCONF_ACK;
112 			auth_chunks->param_hdr.length =
113 					htons(sizeof(sctp_paramhdr_t) + 2);
114 		}
115 	}
116 
117 	/* Initialize the base structure. */
118 	/* What type of endpoint are we?  */
119 	ep->base.type = SCTP_EP_TYPE_SOCKET;
120 
121 	/* Initialize the basic object fields. */
122 	atomic_set(&ep->base.refcnt, 1);
123 	ep->base.dead = 0;
124 	ep->base.malloced = 1;
125 
126 	/* Create an input queue.  */
127 	sctp_inq_init(&ep->base.inqueue);
128 
129 	/* Set its top-half handler */
130 	sctp_inq_set_th_handler(&ep->base.inqueue, sctp_endpoint_bh_rcv);
131 
132 	/* Initialize the bind addr area */
133 	sctp_bind_addr_init(&ep->base.bind_addr, 0);
134 
135 	/* Remember who we are attached to.  */
136 	ep->base.sk = sk;
137 	sock_hold(ep->base.sk);
138 
139 	/* Create the lists of associations.  */
140 	INIT_LIST_HEAD(&ep->asocs);
141 
142 	/* Use SCTP specific send buffer space queues.  */
143 	ep->sndbuf_policy = sctp_sndbuf_policy;
144 
145 	sk->sk_data_ready = sctp_data_ready;
146 	sk->sk_write_space = sctp_write_space;
147 	sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
148 
149 	/* Get the receive buffer policy for this endpoint */
150 	ep->rcvbuf_policy = sctp_rcvbuf_policy;
151 
152 	/* Initialize the secret key used with cookie. */
153 	get_random_bytes(&ep->secret_key[0], SCTP_SECRET_SIZE);
154 	ep->last_key = ep->current_key = 0;
155 	ep->key_changed_at = jiffies;
156 
157 	/* SCTP-AUTH extensions*/
158 	INIT_LIST_HEAD(&ep->endpoint_shared_keys);
159 	null_key = sctp_auth_shkey_create(0, GFP_KERNEL);
160 	if (!null_key)
161 		goto nomem;
162 
163 	list_add(&null_key->key_list, &ep->endpoint_shared_keys);
164 
165 	/* Allocate and initialize transorms arrays for suported HMACs. */
166 	err = sctp_auth_init_hmacs(ep, gfp);
167 	if (err)
168 		goto nomem_hmacs;
169 
170 	/* Add the null key to the endpoint shared keys list and
171 	 * set the hmcas and chunks pointers.
172 	 */
173 	ep->auth_hmacs_list = auth_hmacs;
174 	ep->auth_chunk_list = auth_chunks;
175 
176 	return ep;
177 
178 nomem_hmacs:
179 	sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
180 nomem:
181 	/* Free all allocations */
182 	kfree(auth_hmacs);
183 	kfree(auth_chunks);
184 	kfree(ep->digest);
185 	return NULL;
186 
187 }
188 
189 /* Create a sctp_endpoint with all that boring stuff initialized.
190  * Returns NULL if there isn't enough memory.
191  */
192 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp)
193 {
194 	struct sctp_endpoint *ep;
195 
196 	/* Build a local endpoint. */
197 	ep = t_new(struct sctp_endpoint, gfp);
198 	if (!ep)
199 		goto fail;
200 	if (!sctp_endpoint_init(ep, sk, gfp))
201 		goto fail_init;
202 	ep->base.malloced = 1;
203 	SCTP_DBG_OBJCNT_INC(ep);
204 	return ep;
205 
206 fail_init:
207 	kfree(ep);
208 fail:
209 	return NULL;
210 }
211 
212 /* Add an association to an endpoint.  */
213 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep,
214 			    struct sctp_association *asoc)
215 {
216 	struct sock *sk = ep->base.sk;
217 
218 	/* If this is a temporary association, don't bother
219 	 * since we'll be removing it shortly and don't
220 	 * want anyone to find it anyway.
221 	 */
222 	if (asoc->temp)
223 		return;
224 
225 	/* Now just add it to our list of asocs */
226 	list_add_tail(&asoc->asocs, &ep->asocs);
227 
228 	/* Increment the backlog value for a TCP-style listening socket. */
229 	if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
230 		sk->sk_ack_backlog++;
231 }
232 
233 /* Free the endpoint structure.  Delay cleanup until
234  * all users have released their reference count on this structure.
235  */
236 void sctp_endpoint_free(struct sctp_endpoint *ep)
237 {
238 	ep->base.dead = 1;
239 
240 	ep->base.sk->sk_state = SCTP_SS_CLOSED;
241 
242 	/* Unlink this endpoint, so we can't find it again! */
243 	sctp_unhash_endpoint(ep);
244 
245 	sctp_endpoint_put(ep);
246 }
247 
248 /* Final destructor for endpoint.  */
249 static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
250 {
251 	SCTP_ASSERT(ep->base.dead, "Endpoint is not dead", return);
252 
253 	/* Free up the HMAC transform. */
254 	crypto_free_hash(sctp_sk(ep->base.sk)->hmac);
255 
256 	/* Free the digest buffer */
257 	kfree(ep->digest);
258 
259 	/* SCTP-AUTH: Free up AUTH releated data such as shared keys
260 	 * chunks and hmacs arrays that were allocated
261 	 */
262 	sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
263 	kfree(ep->auth_hmacs_list);
264 	kfree(ep->auth_chunk_list);
265 
266 	/* AUTH - Free any allocated HMAC transform containers */
267 	sctp_auth_destroy_hmacs(ep->auth_hmacs);
268 
269 	/* Cleanup. */
270 	sctp_inq_free(&ep->base.inqueue);
271 	sctp_bind_addr_free(&ep->base.bind_addr);
272 
273 	/* Remove and free the port */
274 	if (sctp_sk(ep->base.sk)->bind_hash)
275 		sctp_put_port(ep->base.sk);
276 
277 	/* Give up our hold on the sock. */
278 	if (ep->base.sk)
279 		sock_put(ep->base.sk);
280 
281 	/* Finally, free up our memory. */
282 	if (ep->base.malloced) {
283 		kfree(ep);
284 		SCTP_DBG_OBJCNT_DEC(ep);
285 	}
286 }
287 
288 /* Hold a reference to an endpoint. */
289 void sctp_endpoint_hold(struct sctp_endpoint *ep)
290 {
291 	atomic_inc(&ep->base.refcnt);
292 }
293 
294 /* Release a reference to an endpoint and clean up if there are
295  * no more references.
296  */
297 void sctp_endpoint_put(struct sctp_endpoint *ep)
298 {
299 	if (atomic_dec_and_test(&ep->base.refcnt))
300 		sctp_endpoint_destroy(ep);
301 }
302 
303 /* Is this the endpoint we are looking for?  */
304 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
305 					       const union sctp_addr *laddr)
306 {
307 	struct sctp_endpoint *retval = NULL;
308 
309 	if (htons(ep->base.bind_addr.port) == laddr->v4.sin_port) {
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 do a linear search of the associations for this endpoint.
320  * We return the matching transport address too.
321  */
322 static 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_association *tmp;
329 	struct sctp_transport *t = NULL;
330 	struct sctp_hashbucket *head;
331 	struct sctp_ep_common *epb;
332 	struct hlist_node *node;
333 	int hash;
334 	int rport;
335 
336 	*transport = NULL;
337 
338 	/* If the local port is not set, there can't be any associations
339 	 * on this endpoint.
340 	 */
341 	if (!ep->base.bind_addr.port)
342 		goto out;
343 
344 	rport = ntohs(paddr->v4.sin_port);
345 
346 	hash = sctp_assoc_hashfn(ep->base.bind_addr.port, rport);
347 	head = &sctp_assoc_hashtable[hash];
348 	read_lock(&head->lock);
349 	sctp_for_each_hentry(epb, node, &head->chain) {
350 		tmp = sctp_assoc(epb);
351 		if (tmp->ep != ep || rport != tmp->peer.port)
352 			continue;
353 
354 		t = sctp_assoc_lookup_paddr(tmp, paddr);
355 		if (t) {
356 			asoc = tmp;
357 			*transport = t;
358 			break;
359 		}
360 	}
361 	read_unlock(&head->lock);
362 out:
363 	return asoc;
364 }
365 
366 /* Lookup association on an endpoint based on a peer address.  BH-safe.  */
367 struct sctp_association *sctp_endpoint_lookup_assoc(
368 	const struct sctp_endpoint *ep,
369 	const union sctp_addr *paddr,
370 	struct sctp_transport **transport)
371 {
372 	struct sctp_association *asoc;
373 
374 	sctp_local_bh_disable();
375 	asoc = __sctp_endpoint_lookup_assoc(ep, paddr, transport);
376 	sctp_local_bh_enable();
377 
378 	return asoc;
379 }
380 
381 /* Look for any peeled off association from the endpoint that matches the
382  * given peer address.
383  */
384 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
385 				const union sctp_addr *paddr)
386 {
387 	struct sctp_sockaddr_entry *addr;
388 	struct sctp_bind_addr *bp;
389 
390 	bp = &ep->base.bind_addr;
391 	/* This function is called with the socket lock held,
392 	 * so the address_list can not change.
393 	 */
394 	list_for_each_entry(addr, &bp->address_list, list) {
395 		if (sctp_has_association(&addr->a, paddr))
396 			return 1;
397 	}
398 
399 	return 0;
400 }
401 
402 /* Do delayed input processing.  This is scheduled by sctp_rcv().
403  * This may be called on BH or task time.
404  */
405 static void sctp_endpoint_bh_rcv(struct work_struct *work)
406 {
407 	struct sctp_endpoint *ep =
408 		container_of(work, struct sctp_endpoint,
409 			     base.inqueue.immediate);
410 	struct sctp_association *asoc;
411 	struct sock *sk;
412 	struct sctp_transport *transport;
413 	struct sctp_chunk *chunk;
414 	struct sctp_inq *inqueue;
415 	sctp_subtype_t subtype;
416 	sctp_state_t state;
417 	int error = 0;
418 	int first_time = 1;	/* is this the first time through the loop */
419 
420 	if (ep->base.dead)
421 		return;
422 
423 	asoc = NULL;
424 	inqueue = &ep->base.inqueue;
425 	sk = ep->base.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(SCTP_MIB_INCTRLCHUNKS);
478 
479 		if (chunk->transport)
480 			chunk->transport->last_time_heard = jiffies;
481 
482 		error = sctp_do_sm(SCTP_EVENT_T_CHUNK, subtype, state,
483 				   ep, asoc, chunk, GFP_ATOMIC);
484 
485 		if (error && chunk)
486 			chunk->pdiscard = 1;
487 
488 		/* Check to see if the endpoint is freed in response to
489 		 * the incoming chunk. If so, get out of the while loop.
490 		 */
491 		if (!sctp_sk(sk)->ep)
492 			break;
493 
494 		if (first_time)
495 			first_time = 0;
496 	}
497 }
498