summaryrefslogtreecommitdiffstats
path: root/net/sctp/endpointola.c
blob: 410ddc1e344389cae97cb86327309516b0487c96 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
/* SCTP kernel implementation
 * Copyright (c) 1999-2000 Cisco, Inc.
 * Copyright (c) 1999-2001 Motorola, Inc.
 * Copyright (c) 2001-2002 International Business Machines, Corp.
 * Copyright (c) 2001 Intel Corp.
 * Copyright (c) 2001 Nokia, Inc.
 * Copyright (c) 2001 La Monte H.P. Yarroll
 *
 * This file is part of the SCTP kernel implementation
 *
 * This abstraction represents an SCTP endpoint.
 *
 * The SCTP implementation is free software;
 * you can redistribute it and/or modify it under the terms of
 * the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * The SCTP implementation is distributed in the hope that it
 * will be useful, but WITHOUT ANY WARRANTY; without even the implied
 *                 ************************
 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GNU CC; see the file COPYING.  If not, see
 * <http://www.gnu.org/licenses/>.
 *
 * Please send any bug reports or fixes you make to the
 * email address(es):
 *    lksctp developers <linux-sctp@vger.kernel.org>
 *
 * Written or modified by:
 *    La Monte H.P. Yarroll <piggy@acm.org>
 *    Karl Knutson <karl@athena.chicago.il.us>
 *    Jon Grimm <jgrimm@austin.ibm.com>
 *    Daisy Chang <daisyc@us.ibm.com>
 *    Dajiang Zhang <dajiang.zhang@nokia.com>
 */

#include <linux/types.h>
#include <linux/slab.h>
#include <linux/in.h>
#include <linux/random.h>	/* get_random_bytes() */
#include <net/sock.h>
#include <net/ipv6.h>
#include <net/sctp/sctp.h>
#include <net/sctp/sm.h>

/* Forward declarations for internal helpers. */
static void sctp_endpoint_bh_rcv(struct work_struct *work);

/*
 * Initialize the base fields of the endpoint structure.
 */
static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep,
						struct sock *sk,
						gfp_t gfp)
{
	struct net *net = sock_net(sk);
	struct sctp_hmac_algo_param *auth_hmacs = NULL;
	struct sctp_chunks_param *auth_chunks = NULL;
	struct sctp_shared_key *null_key;
	int err;

	ep->digest = kzalloc(SCTP_SIGNATURE_SIZE, gfp);
	if (!ep->digest)
		return NULL;

	ep->auth_enable = net->sctp.auth_enable;
	if (ep->auth_enable) {
		/* Allocate space for HMACS and CHUNKS authentication
		 * variables.  There are arrays that we encode directly
		 * into parameters to make the rest of the operations easier.
		 */
		auth_hmacs = kzalloc(sizeof(sctp_hmac_algo_param_t) +
				sizeof(__u16) * SCTP_AUTH_NUM_HMACS, gfp);
		if (!auth_hmacs)
			goto nomem;

		auth_chunks = kzalloc(sizeof(sctp_chunks_param_t) +
					SCTP_NUM_CHUNK_TYPES, gfp);
		if (!auth_chunks)
			goto nomem;

		/* Initialize the HMACS parameter.
		 * SCTP-AUTH: Section 3.3
		 *    Every endpoint supporting SCTP chunk authentication MUST
		 *    support the HMAC based on the SHA-1 algorithm.
		 */
		auth_hmacs->param_hdr.type = SCTP_PARAM_HMAC_ALGO;
		auth_hmacs->param_hdr.length =
					htons(sizeof(sctp_paramhdr_t) + 2);
		auth_hmacs->hmac_ids[0] = htons(SCTP_AUTH_HMAC_ID_SHA1);

		/* Initialize the CHUNKS parameter */
		auth_chunks->param_hdr.type = SCTP_PARAM_CHUNKS;
		auth_chunks->param_hdr.length = htons(sizeof(sctp_paramhdr_t));

		/* If the Add-IP functionality is enabled, we must
		 * authenticate, ASCONF and ASCONF-ACK chunks
		 */
		if (net->sctp.addip_enable) {
			auth_chunks->chunks[0] = SCTP_CID_ASCONF;
			auth_chunks->chunks[1] = SCTP_CID_ASCONF_ACK;
			auth_chunks->param_hdr.length =
					htons(sizeof(sctp_paramhdr_t) + 2);
		}
	}

	/* Initialize the base structure. */
	/* What type of endpoint are we?  */
	ep->base.type = SCTP_EP_TYPE_SOCKET;

	/* Initialize the basic object fields. */
	atomic_set(&ep->base.refcnt, 1);
	ep->base.dead = false;

	/* Create an input queue.  */
	sctp_inq_init(&ep->base.inqueue);

	/* Set its top-half handler */
	sctp_inq_set_th_handler(&ep->base.inqueue, sctp_endpoint_bh_rcv);

	/* Initialize the bind addr area */
	sctp_bind_addr_init(&ep->base.bind_addr, 0);

	/* Remember who we are attached to.  */
	ep->base.sk = sk;
	sock_hold(ep->base.sk);

	/* Create the lists of associations.  */
	INIT_LIST_HEAD(&ep->asocs);

	/* Use SCTP specific send buffer space queues.  */
	ep->sndbuf_policy = net->sctp.sndbuf_policy;

	sk->sk_data_ready = sctp_data_ready;
	sk->sk_write_space = sctp_write_space;
	sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);

	/* Get the receive buffer policy for this endpoint */
	ep->rcvbuf_policy = net->sctp.rcvbuf_policy;

	/* Initialize the secret key used with cookie. */
	get_random_bytes(ep->secret_key, sizeof(ep->secret_key));

	/* SCTP-AUTH extensions*/
	INIT_LIST_HEAD(&ep->endpoint_shared_keys);
	null_key = sctp_auth_shkey_create(0, gfp);
	if (!null_key)
		goto nomem;

	list_add(&null_key->key_list, &ep->endpoint_shared_keys);

	/* Allocate and initialize transorms arrays for supported HMACs. */
	err = sctp_auth_init_hmacs(ep, gfp);
	if (err)
		goto nomem_hmacs;

	/* Add the null key to the endpoint shared keys list and
	 * set the hmcas and chunks pointers.
	 */
	ep->auth_hmacs_list = auth_hmacs;
	ep->auth_chunk_list = auth_chunks;
	ep->prsctp_enable = net->sctp.prsctp_enable;

	return ep;

nomem_hmacs:
	sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
nomem:
	/* Free all allocations */
	kfree(auth_hmacs);
	kfree(auth_chunks);
	kfree(ep->digest);
	return NULL;

}

/* Create a sctp_endpoint with all that boring stuff initialized.
 * Returns NULL if there isn't enough memory.
 */
struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp)
{
	struct sctp_endpoint *ep;

	/* Build a local endpoint. */
	ep = kzalloc(sizeof(*ep), gfp);
	if (!ep)
		goto fail;

	if (!sctp_endpoint_init(ep, sk, gfp))
		goto fail_init;

	SCTP_DBG_OBJCNT_INC(ep);
	return ep;

fail_init:
	kfree(ep);
fail:
	return NULL;
}

/* Add an association to an endpoint.  */
void sctp_endpoint_add_asoc(struct sctp_endpoint *ep,
			    struct sctp_association *asoc)
{
	struct sock *sk = ep->base.sk;

	/* If this is a temporary association, don't bother
	 * since we'll be removing it shortly and don't
	 * want anyone to find it anyway.
	 */
	if (asoc->temp)
		return;

	/* Now just add it to our list of asocs */
	list_add_tail(&asoc->asocs, &ep->asocs);

	/* Increment the backlog value for a TCP-style listening socket. */
	if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
		sk->sk_ack_backlog++;
}

/* Free the endpoint structure.  Delay cleanup until
 * all users have released their reference count on this structure.
 */
void sctp_endpoint_free(struct sctp_endpoint *ep)
{
	ep->base.dead = true;

	ep->base.sk->sk_state = SCTP_SS_CLOSED;

	/* Unlink this endpoint, so we can't find it again! */
	sctp_unhash_endpoint(ep);

	sctp_endpoint_put(ep);
}

/* Final destructor for endpoint.  */
static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
{
	struct sock *sk;

	if (unlikely(!ep->base.dead)) {
		WARN(1, "Attempt to destroy undead endpoint %p!\n", ep);
		return;
	}

	/* Free the digest buffer */
	kfree(ep->digest);

	/* SCTP-AUTH: Free up AUTH releated data such as shared keys
	 * chunks and hmacs arrays that were allocated
	 */
	sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
	kfree(ep->auth_hmacs_list);
	kfree(ep->auth_chunk_list);

	/* AUTH - Free any allocated HMAC transform containers */
	sctp_auth_destroy_hmacs(ep->auth_hmacs);

	/* Cleanup. */
	sctp_inq_free(&ep->base.inqueue);
	sctp_bind_addr_free(&ep->base.bind_addr);

	memset(ep->secret_key, 0, sizeof(ep->secret_key));

	/* Give up our hold on the sock. */
	sk = ep->base.sk;
	if (sk != NULL) {
		/* Remove and free the port */
		if (sctp_sk(sk)->bind_hash)
			sctp_put_port(sk);

		sock_put(sk);
	}

	kfree(ep);
	SCTP_DBG_OBJCNT_DEC(ep);
}

/* Hold a reference to an endpoint. */
void sctp_endpoint_hold(struct sctp_endpoint *ep)
{
	atomic_inc(&ep->base.refcnt);
}

/* Release a reference to an endpoint and clean up if there are
 * no more references.
 */
void sctp_endpoint_put(struct sctp_endpoint *ep)
{
	if (atomic_dec_and_test(&ep->base.refcnt))
		sctp_endpoint_destroy(ep);
}

/* Is this the endpoint we are looking for?  */
struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
					       struct net *net,
					       const union sctp_addr *laddr)
{
	struct sctp_endpoint *retval = NULL;

	if ((htons(ep->base.bind_addr.port) == laddr->v4.sin_port) &&
	    net_eq(sock_net(ep->base.sk), net)) {
		if (sctp_bind_addr_match(&ep->base.bind_addr, laddr,
					 sctp_sk(ep->base.sk)))
			retval = ep;
	}

	return retval;
}

/* Find the association that goes with this chunk.
 * We lookup the transport from hashtable at first, then get association
 * through t->assoc.
 */
struct sctp_association *sctp_endpoint_lookup_assoc(
	const struct sctp_endpoint *ep,
	const union sctp_addr *paddr,
	struct sctp_transport **transport)
{
	struct sctp_association *asoc = NULL;
	struct sctp_transport *t;

	*transport = NULL;

	/* If the local port is not set, there can't be any associations
	 * on this endpoint.
	 */
	if (!ep->base.bind_addr.port)
		return NULL;

	rcu_read_lock();
	t = sctp_epaddr_lookup_transport(ep, paddr);
	if (!t)
		goto out;

	*transport = t;
	asoc = t->asoc;
out:
	rcu_read_unlock();
	return asoc;
}

/* Look for any peeled off association from the endpoint that matches the
 * given peer address.
 */
int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
				const union sctp_addr *paddr)
{
	struct sctp_sockaddr_entry *addr;
	struct sctp_bind_addr *bp;
	struct net *net = sock_net(ep->base.sk);

	bp = &ep->base.bind_addr;
	/* This function is called with the socket lock held,
	 * so the address_list can not change.
	 */
	list_for_each_entry(addr, &bp->address_list, list) {
		if (sctp_has_association(net, &addr->a, paddr))
			return 1;
	}

	return 0;
}

/* Do delayed input processing.  This is scheduled by sctp_rcv().
 * This may be called on BH or task time.
 */
static void sctp_endpoint_bh_rcv(struct work_struct *work)
{
	struct sctp_endpoint *ep =
		container_of(work, struct sctp_endpoint,
			     base.inqueue.immediate);
	struct sctp_association *asoc;
	struct sock *sk;
	struct net *net;
	struct sctp_transport *transport;
	struct sctp_chunk *chunk;
	struct sctp_inq *inqueue;
	sctp_subtype_t subtype;
	sctp_state_t state;
	int error = 0;
	int first_time = 1;	/* is this the first time through the loop */

	if (ep->base.dead)
		return;

	asoc = NULL;
	inqueue = &ep->base.inqueue;
	sk = ep->base.sk;
	net = sock_net(sk);

	while (NULL != (chunk = sctp_inq_pop(inqueue))) {
		subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);

		/* If the first chunk in the packet is AUTH, do special
		 * processing specified in Section 6.3 of SCTP-AUTH spec
		 */
		if (first_time && (subtype.chunk == SCTP_CID_AUTH)) {
			struct sctp_chunkhdr *next_hdr;

			next_hdr = sctp_inq_peek(inqueue);
			if (!next_hdr)
				goto normal;

			/* If the next chunk is COOKIE-ECHO, skip the AUTH
			 * chunk while saving a pointer to it so we can do
			 * Authentication later (during cookie-echo
			 * processing).
			 */
			if (next_hdr->type == SCTP_CID_COOKIE_ECHO) {
				chunk->auth_chunk = skb_clone(chunk->skb,
								GFP_ATOMIC);
				chunk->auth = 1;
				continue;
			}
		}
normal:
		/* We might have grown an association since last we
		 * looked, so try again.
		 *
		 * This happens when we've just processed our
		 * COOKIE-ECHO chunk.
		 */
		if (NULL == chunk->asoc) {
			asoc = sctp_endpoint_lookup_assoc(ep,
							  sctp_source(chunk),
							  &transport);
			chunk->asoc = asoc;
			chunk->transport = transport;
		}

		state = asoc ? asoc->state : SCTP_STATE_CLOSED;
		if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
			continue;

		/* Remember where the last DATA chunk came from so we
		 * know where to send the SACK.
		 */
		if (asoc && sctp_chunk_is_data(chunk))
			asoc->peer.last_data_from = chunk->transport;
		else {
			SCTP_INC_STATS(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS);
			if (asoc)
				asoc->stats.ictrlchunks++;
		}

		if (chunk->transport)
			chunk->transport->last_time_heard = ktime_get();

		error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state,
				   ep, asoc, chunk, GFP_ATOMIC);

		if (error && chunk)
			chunk->pdiscard = 1;

		/* Check to see if the endpoint is freed in response to
		 * the incoming chunk. If so, get out of the while loop.
		 */
		if (!sctp_sk(sk)->ep)
			break;

		if (first_time)
			first_time = 0;
	}
}