xref: /openbmc/linux/net/sctp/endpointola.c (revision 64c70b1c)
1 /* SCTP kernel reference 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 reference Implementation
10  *
11  * This abstraction represents an SCTP endpoint.
12  *
13  * This file is part of the implementation of the add-IP extension,
14  * based on <draft-ietf-tsvwg-addip-sctp-02.txt> June 29, 2001,
15  * for the SCTP kernel reference Implementation.
16  *
17  * The SCTP reference implementation is free software;
18  * you can redistribute it and/or modify it under the terms of
19  * the GNU General Public License as published by
20  * the Free Software Foundation; either version 2, or (at your option)
21  * any later version.
22  *
23  * The SCTP reference implementation is distributed in the hope that it
24  * will be useful, but WITHOUT ANY WARRANTY; without even the implied
25  *                 ************************
26  * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
27  * See the GNU General Public License for more details.
28  *
29  * You should have received a copy of the GNU General Public License
30  * along with GNU CC; see the file COPYING.  If not, write to
31  * the Free Software Foundation, 59 Temple Place - Suite 330,
32  * Boston, MA 02111-1307, USA.
33  *
34  * Please send any bug reports or fixes you make to the
35  * email address(es):
36  *    lksctp developers <lksctp-developers@lists.sourceforge.net>
37  *
38  * Or submit a bug report through the following website:
39  *    http://www.sf.net/projects/lksctp
40  *
41  * Written or modified by:
42  *    La Monte H.P. Yarroll <piggy@acm.org>
43  *    Karl Knutson <karl@athena.chicago.il.us>
44  *    Jon Grimm <jgrimm@austin.ibm.com>
45  *    Daisy Chang <daisyc@us.ibm.com>
46  *    Dajiang Zhang <dajiang.zhang@nokia.com>
47  *
48  * Any bugs reported given to us we will try to fix... any fixes shared will
49  * be incorporated into the next SCTP release.
50  */
51 
52 #include <linux/types.h>
53 #include <linux/slab.h>
54 #include <linux/in.h>
55 #include <linux/random.h>	/* get_random_bytes() */
56 #include <linux/crypto.h>
57 #include <net/sock.h>
58 #include <net/ipv6.h>
59 #include <net/sctp/sctp.h>
60 #include <net/sctp/sm.h>
61 
62 /* Forward declarations for internal helpers. */
63 static void sctp_endpoint_bh_rcv(struct work_struct *work);
64 
65 /*
66  * Initialize the base fields of the endpoint structure.
67  */
68 static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep,
69 						struct sock *sk,
70 						gfp_t gfp)
71 {
72 	memset(ep, 0, sizeof(struct sctp_endpoint));
73 
74 	ep->digest = kzalloc(SCTP_SIGNATURE_SIZE, gfp);
75 	if (!ep->digest)
76 		return NULL;
77 
78 	/* Initialize the base structure. */
79 	/* What type of endpoint are we?  */
80 	ep->base.type = SCTP_EP_TYPE_SOCKET;
81 
82 	/* Initialize the basic object fields. */
83 	atomic_set(&ep->base.refcnt, 1);
84 	ep->base.dead = 0;
85 	ep->base.malloced = 1;
86 
87 	/* Create an input queue.  */
88 	sctp_inq_init(&ep->base.inqueue);
89 
90 	/* Set its top-half handler */
91 	sctp_inq_set_th_handler(&ep->base.inqueue, sctp_endpoint_bh_rcv);
92 
93 	/* Initialize the bind addr area */
94 	sctp_bind_addr_init(&ep->base.bind_addr, 0);
95 	rwlock_init(&ep->base.addr_lock);
96 
97 	/* Remember who we are attached to.  */
98 	ep->base.sk = sk;
99 	sock_hold(ep->base.sk);
100 
101 	/* Create the lists of associations.  */
102 	INIT_LIST_HEAD(&ep->asocs);
103 
104 	/* Use SCTP specific send buffer space queues.  */
105 	ep->sndbuf_policy = sctp_sndbuf_policy;
106 	sk->sk_write_space = sctp_write_space;
107 	sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
108 
109 	/* Get the receive buffer policy for this endpoint */
110 	ep->rcvbuf_policy = sctp_rcvbuf_policy;
111 
112 	/* Initialize the secret key used with cookie. */
113 	get_random_bytes(&ep->secret_key[0], SCTP_SECRET_SIZE);
114 	ep->last_key = ep->current_key = 0;
115 	ep->key_changed_at = jiffies;
116 
117 	return ep;
118 }
119 
120 /* Create a sctp_endpoint with all that boring stuff initialized.
121  * Returns NULL if there isn't enough memory.
122  */
123 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp)
124 {
125 	struct sctp_endpoint *ep;
126 
127 	/* Build a local endpoint. */
128 	ep = t_new(struct sctp_endpoint, gfp);
129 	if (!ep)
130 		goto fail;
131 	if (!sctp_endpoint_init(ep, sk, gfp))
132 		goto fail_init;
133 	ep->base.malloced = 1;
134 	SCTP_DBG_OBJCNT_INC(ep);
135 	return ep;
136 
137 fail_init:
138 	kfree(ep);
139 fail:
140 	return NULL;
141 }
142 
143 /* Add an association to an endpoint.  */
144 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep,
145 			    struct sctp_association *asoc)
146 {
147 	struct sock *sk = ep->base.sk;
148 
149 	/* If this is a temporary association, don't bother
150 	 * since we'll be removing it shortly and don't
151 	 * want anyone to find it anyway.
152 	 */
153 	if (asoc->temp)
154 		return;
155 
156 	/* Now just add it to our list of asocs */
157 	list_add_tail(&asoc->asocs, &ep->asocs);
158 
159 	/* Increment the backlog value for a TCP-style listening socket. */
160 	if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
161 		sk->sk_ack_backlog++;
162 }
163 
164 /* Free the endpoint structure.  Delay cleanup until
165  * all users have released their reference count on this structure.
166  */
167 void sctp_endpoint_free(struct sctp_endpoint *ep)
168 {
169 	ep->base.dead = 1;
170 
171 	ep->base.sk->sk_state = SCTP_SS_CLOSED;
172 
173 	/* Unlink this endpoint, so we can't find it again! */
174 	sctp_unhash_endpoint(ep);
175 
176 	sctp_endpoint_put(ep);
177 }
178 
179 /* Final destructor for endpoint.  */
180 static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
181 {
182 	SCTP_ASSERT(ep->base.dead, "Endpoint is not dead", return);
183 
184 	/* Free up the HMAC transform. */
185 	crypto_free_hash(sctp_sk(ep->base.sk)->hmac);
186 
187 	/* Free the digest buffer */
188 	kfree(ep->digest);
189 
190 	/* Cleanup. */
191 	sctp_inq_free(&ep->base.inqueue);
192 	sctp_bind_addr_free(&ep->base.bind_addr);
193 
194 	/* Remove and free the port */
195 	if (sctp_sk(ep->base.sk)->bind_hash)
196 		sctp_put_port(ep->base.sk);
197 
198 	/* Give up our hold on the sock. */
199 	if (ep->base.sk)
200 		sock_put(ep->base.sk);
201 
202 	/* Finally, free up our memory. */
203 	if (ep->base.malloced) {
204 		kfree(ep);
205 		SCTP_DBG_OBJCNT_DEC(ep);
206 	}
207 }
208 
209 /* Hold a reference to an endpoint. */
210 void sctp_endpoint_hold(struct sctp_endpoint *ep)
211 {
212 	atomic_inc(&ep->base.refcnt);
213 }
214 
215 /* Release a reference to an endpoint and clean up if there are
216  * no more references.
217  */
218 void sctp_endpoint_put(struct sctp_endpoint *ep)
219 {
220 	if (atomic_dec_and_test(&ep->base.refcnt))
221 		sctp_endpoint_destroy(ep);
222 }
223 
224 /* Is this the endpoint we are looking for?  */
225 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
226 					       const union sctp_addr *laddr)
227 {
228 	struct sctp_endpoint *retval;
229 
230 	sctp_read_lock(&ep->base.addr_lock);
231 	if (htons(ep->base.bind_addr.port) == laddr->v4.sin_port) {
232 		if (sctp_bind_addr_match(&ep->base.bind_addr, laddr,
233 					 sctp_sk(ep->base.sk))) {
234 			retval = ep;
235 			goto out;
236 		}
237 	}
238 
239 	retval = NULL;
240 
241 out:
242 	sctp_read_unlock(&ep->base.addr_lock);
243 	return retval;
244 }
245 
246 /* Find the association that goes with this chunk.
247  * We do a linear search of the associations for this endpoint.
248  * We return the matching transport address too.
249  */
250 static struct sctp_association *__sctp_endpoint_lookup_assoc(
251 	const struct sctp_endpoint *ep,
252 	const union sctp_addr *paddr,
253 	struct sctp_transport **transport)
254 {
255 	int rport;
256 	struct sctp_association *asoc;
257 	struct list_head *pos;
258 
259 	rport = ntohs(paddr->v4.sin_port);
260 
261 	list_for_each(pos, &ep->asocs) {
262 		asoc = list_entry(pos, struct sctp_association, asocs);
263 		if (rport == asoc->peer.port) {
264 			sctp_read_lock(&asoc->base.addr_lock);
265 			*transport = sctp_assoc_lookup_paddr(asoc, paddr);
266 			sctp_read_unlock(&asoc->base.addr_lock);
267 
268 			if (*transport)
269 				return asoc;
270 		}
271 	}
272 
273 	*transport = NULL;
274 	return NULL;
275 }
276 
277 /* Lookup association on an endpoint based on a peer address.  BH-safe.  */
278 struct sctp_association *sctp_endpoint_lookup_assoc(
279 	const struct sctp_endpoint *ep,
280 	const union sctp_addr *paddr,
281 	struct sctp_transport **transport)
282 {
283 	struct sctp_association *asoc;
284 
285 	sctp_local_bh_disable();
286 	asoc = __sctp_endpoint_lookup_assoc(ep, paddr, transport);
287 	sctp_local_bh_enable();
288 
289 	return asoc;
290 }
291 
292 /* Look for any peeled off association from the endpoint that matches the
293  * given peer address.
294  */
295 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
296 				const union sctp_addr *paddr)
297 {
298 	struct list_head *pos;
299 	struct sctp_sockaddr_entry *addr;
300 	struct sctp_bind_addr *bp;
301 
302 	sctp_read_lock(&ep->base.addr_lock);
303 	bp = &ep->base.bind_addr;
304 	list_for_each(pos, &bp->address_list) {
305 		addr = list_entry(pos, struct sctp_sockaddr_entry, list);
306 		if (sctp_has_association(&addr->a, paddr)) {
307 			sctp_read_unlock(&ep->base.addr_lock);
308 			return 1;
309 		}
310 	}
311 	sctp_read_unlock(&ep->base.addr_lock);
312 
313 	return 0;
314 }
315 
316 /* Do delayed input processing.  This is scheduled by sctp_rcv().
317  * This may be called on BH or task time.
318  */
319 static void sctp_endpoint_bh_rcv(struct work_struct *work)
320 {
321 	struct sctp_endpoint *ep =
322 		container_of(work, struct sctp_endpoint,
323 			     base.inqueue.immediate);
324 	struct sctp_association *asoc;
325 	struct sock *sk;
326 	struct sctp_transport *transport;
327 	struct sctp_chunk *chunk;
328 	struct sctp_inq *inqueue;
329 	sctp_subtype_t subtype;
330 	sctp_state_t state;
331 	int error = 0;
332 
333 	if (ep->base.dead)
334 		return;
335 
336 	asoc = NULL;
337 	inqueue = &ep->base.inqueue;
338 	sk = ep->base.sk;
339 
340 	while (NULL != (chunk = sctp_inq_pop(inqueue))) {
341 		subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
342 
343 		/* We might have grown an association since last we
344 		 * looked, so try again.
345 		 *
346 		 * This happens when we've just processed our
347 		 * COOKIE-ECHO chunk.
348 		 */
349 		if (NULL == chunk->asoc) {
350 			asoc = sctp_endpoint_lookup_assoc(ep,
351 							  sctp_source(chunk),
352 							  &transport);
353 			chunk->asoc = asoc;
354 			chunk->transport = transport;
355 		}
356 
357 		state = asoc ? asoc->state : SCTP_STATE_CLOSED;
358 
359 		/* Remember where the last DATA chunk came from so we
360 		 * know where to send the SACK.
361 		 */
362 		if (asoc && sctp_chunk_is_data(chunk))
363 			asoc->peer.last_data_from = chunk->transport;
364 		else
365 			SCTP_INC_STATS(SCTP_MIB_INCTRLCHUNKS);
366 
367 		if (chunk->transport)
368 			chunk->transport->last_time_heard = jiffies;
369 
370 		error = sctp_do_sm(SCTP_EVENT_T_CHUNK, subtype, state,
371 				   ep, asoc, chunk, GFP_ATOMIC);
372 
373 		if (error && chunk)
374 			chunk->pdiscard = 1;
375 
376 		/* Check to see if the endpoint is freed in response to
377 		 * the incoming chunk. If so, get out of the while loop.
378 		 */
379 		if (!sctp_sk(sk)->ep)
380 			break;
381 	}
382 }
383