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/sched.h>
54 #include <linux/slab.h>
55 #include <linux/in.h>
56 #include <linux/random.h> /* get_random_bytes() */
57 #include <linux/crypto.h>
58 #include <net/sock.h>
59 #include <net/ipv6.h>
60 #include <net/sctp/sctp.h>
61 #include <net/sctp/sm.h>
62
63 /* Forward declarations for internal helpers. */
64 static void sctp_endpoint_bh_rcv(struct sctp_endpoint *ep);
65
66 /*
67 * Initialize the base fields of the endpoint structure.
68 */
sctp_endpoint_init(struct sctp_endpoint * ep,struct sock * sk,int gfp)69 static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep,
70 struct sock *sk, int gfp)
71 {
72 struct sctp_opt *sp = sctp_sk(sk);
73 memset(ep, 0, sizeof(struct sctp_endpoint));
74
75 /* Initialize the base structure. */
76 /* What type of endpoint are we? */
77 ep->base.type = SCTP_EP_TYPE_SOCKET;
78
79 /* Initialize the basic object fields. */
80 atomic_set(&ep->base.refcnt, 1);
81 ep->base.dead = 0;
82 ep->base.malloced = 1;
83
84 /* Create an input queue. */
85 sctp_inq_init(&ep->base.inqueue);
86
87 /* Set its top-half handler */
88 sctp_inq_set_th_handler(&ep->base.inqueue,
89 (void (*)(void *))sctp_endpoint_bh_rcv, ep);
90
91 /* Initialize the bind addr area */
92 sctp_bind_addr_init(&ep->base.bind_addr, 0);
93 ep->base.addr_lock = RW_LOCK_UNLOCKED;
94
95 /* Remember who we are attached to. */
96 ep->base.sk = sk;
97 sock_hold(ep->base.sk);
98
99 /* Create the lists of associations. */
100 INIT_LIST_HEAD(&ep->asocs);
101
102 /* Set up the base timeout information. */
103 ep->timeouts[SCTP_EVENT_TIMEOUT_NONE] = 0;
104 ep->timeouts[SCTP_EVENT_TIMEOUT_T1_COOKIE] =
105 SCTP_DEFAULT_TIMEOUT_T1_COOKIE;
106 ep->timeouts[SCTP_EVENT_TIMEOUT_T1_INIT] =
107 SCTP_DEFAULT_TIMEOUT_T1_INIT;
108 ep->timeouts[SCTP_EVENT_TIMEOUT_T2_SHUTDOWN] =
109 SCTP_MSECS_TO_JIFFIES(sp->rtoinfo.srto_initial);
110 ep->timeouts[SCTP_EVENT_TIMEOUT_T3_RTX] = 0;
111 ep->timeouts[SCTP_EVENT_TIMEOUT_T4_RTO] = 0;
112
113 /* sctpimpguide-05 Section 2.12.2
114 * If the 'T5-shutdown-guard' timer is used, it SHOULD be set to the
115 * recommended value of 5 times 'RTO.Max'.
116 */
117 ep->timeouts[SCTP_EVENT_TIMEOUT_T5_SHUTDOWN_GUARD]
118 = 5 * SCTP_MSECS_TO_JIFFIES(sp->rtoinfo.srto_max);
119
120 ep->timeouts[SCTP_EVENT_TIMEOUT_HEARTBEAT] =
121 SCTP_DEFAULT_TIMEOUT_HEARTBEAT;
122 ep->timeouts[SCTP_EVENT_TIMEOUT_SACK] =
123 SCTP_DEFAULT_TIMEOUT_SACK;
124 ep->timeouts[SCTP_EVENT_TIMEOUT_AUTOCLOSE] =
125 sp->autoclose * HZ;
126
127 /* Use SCTP specific send buffer space queues. */
128 sk->write_space = sctp_write_space;
129 sk->use_write_queue = 1;
130
131 /* Initialize the secret key used with cookie. */
132 get_random_bytes(&ep->secret_key[0], SCTP_SECRET_SIZE);
133 ep->last_key = ep->current_key = 0;
134 ep->key_changed_at = jiffies;
135
136 ep->debug_name = "unnamedEndpoint";
137 return ep;
138 }
139
140 /* Create a sctp_endpoint with all that boring stuff initialized.
141 * Returns NULL if there isn't enough memory.
142 */
sctp_endpoint_new(struct sock * sk,int gfp)143 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, int gfp)
144 {
145 struct sctp_endpoint *ep;
146
147 /* Build a local endpoint. */
148 ep = t_new(struct sctp_endpoint, gfp);
149 if (!ep)
150 goto fail;
151 if (!sctp_endpoint_init(ep, sk, gfp))
152 goto fail_init;
153 ep->base.malloced = 1;
154 SCTP_DBG_OBJCNT_INC(ep);
155 return ep;
156
157 fail_init:
158 kfree(ep);
159 fail:
160 return NULL;
161 }
162
163 /* Add an association to an endpoint. */
sctp_endpoint_add_asoc(struct sctp_endpoint * ep,struct sctp_association * asoc)164 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep,
165 struct sctp_association *asoc)
166 {
167 struct sock *sk = ep->base.sk;
168
169 /* Now just add it to our list of asocs */
170 list_add_tail(&asoc->asocs, &ep->asocs);
171
172 /* Increment the backlog value for a TCP-style listening socket. */
173 if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
174 sk->ack_backlog++;
175 }
176
177 /* Free the endpoint structure. Delay cleanup until
178 * all users have released their reference count on this structure.
179 */
sctp_endpoint_free(struct sctp_endpoint * ep)180 void sctp_endpoint_free(struct sctp_endpoint *ep)
181 {
182 ep->base.dead = 1;
183 sctp_endpoint_put(ep);
184 }
185
186 /* Final destructor for endpoint. */
sctp_endpoint_destroy(struct sctp_endpoint * ep)187 static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
188 {
189 SCTP_ASSERT(ep->base.dead, "Endpoint is not dead", return);
190
191 ep->base.sk->state = SCTP_SS_CLOSED;
192
193 /* Unlink this endpoint, so we can't find it again! */
194 sctp_unhash_endpoint(ep);
195
196 /* Free up the HMAC transform. */
197 if (sctp_sk(ep->base.sk)->hmac)
198 sctp_crypto_free_tfm(sctp_sk(ep->base.sk)->hmac);
199
200 /* Cleanup. */
201 sctp_inq_free(&ep->base.inqueue);
202 sctp_bind_addr_free(&ep->base.bind_addr);
203
204 /* Remove and free the port */
205 if (ep->base.sk->prev != NULL)
206 sctp_put_port(ep->base.sk);
207
208 /* Give up our hold on the sock. */
209 if (ep->base.sk)
210 sock_put(ep->base.sk);
211
212 /* Finally, free up our memory. */
213 if (ep->base.malloced) {
214 kfree(ep);
215 SCTP_DBG_OBJCNT_DEC(ep);
216 }
217 }
218
219 /* Hold a reference to an endpoint. */
sctp_endpoint_hold(struct sctp_endpoint * ep)220 void sctp_endpoint_hold(struct sctp_endpoint *ep)
221 {
222 atomic_inc(&ep->base.refcnt);
223 }
224
225 /* Release a reference to an endpoint and clean up if there are
226 * no more references.
227 */
sctp_endpoint_put(struct sctp_endpoint * ep)228 void sctp_endpoint_put(struct sctp_endpoint *ep)
229 {
230 if (atomic_dec_and_test(&ep->base.refcnt))
231 sctp_endpoint_destroy(ep);
232 }
233
234 /* Is this the endpoint we are looking for? */
sctp_endpoint_is_match(struct sctp_endpoint * ep,const union sctp_addr * laddr)235 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
236 const union sctp_addr *laddr)
237 {
238 struct sctp_endpoint *retval;
239
240 sctp_read_lock(&ep->base.addr_lock);
241 if (ep->base.bind_addr.port == laddr->v4.sin_port) {
242 if (sctp_bind_addr_match(&ep->base.bind_addr, laddr,
243 sctp_sk(ep->base.sk))) {
244 retval = ep;
245 goto out;
246 }
247 }
248
249 retval = NULL;
250
251 out:
252 sctp_read_unlock(&ep->base.addr_lock);
253 return retval;
254 }
255
256 /* Find the association that goes with this chunk.
257 * We do a linear search of the associations for this endpoint.
258 * We return the matching transport address too.
259 */
__sctp_endpoint_lookup_assoc(const struct sctp_endpoint * ep,const union sctp_addr * paddr,struct sctp_transport ** transport)260 static struct sctp_association *__sctp_endpoint_lookup_assoc(
261 const struct sctp_endpoint *ep,
262 const union sctp_addr *paddr,
263 struct sctp_transport **transport)
264 {
265 int rport;
266 struct sctp_association *asoc;
267 struct list_head *pos;
268
269 rport = paddr->v4.sin_port;
270
271 list_for_each(pos, &ep->asocs) {
272 asoc = list_entry(pos, struct sctp_association, asocs);
273 if (rport == asoc->peer.port) {
274 sctp_read_lock(&asoc->base.addr_lock);
275 *transport = sctp_assoc_lookup_paddr(asoc, paddr);
276 sctp_read_unlock(&asoc->base.addr_lock);
277
278 if (*transport)
279 return asoc;
280 }
281 }
282
283 *transport = NULL;
284 return NULL;
285 }
286
287 /* Lookup association on an endpoint based on a peer address. BH-safe. */
sctp_endpoint_lookup_assoc(const struct sctp_endpoint * ep,const union sctp_addr * paddr,struct sctp_transport ** transport)288 struct sctp_association *sctp_endpoint_lookup_assoc(
289 const struct sctp_endpoint *ep,
290 const union sctp_addr *paddr,
291 struct sctp_transport **transport)
292 {
293 struct sctp_association *asoc;
294
295 sctp_local_bh_disable();
296 asoc = __sctp_endpoint_lookup_assoc(ep, paddr, transport);
297 sctp_local_bh_enable();
298
299 return asoc;
300 }
301
302 /* Look for any peeled off association from the endpoint that matches the
303 * given peer address.
304 */
sctp_endpoint_is_peeled_off(struct sctp_endpoint * ep,const union sctp_addr * paddr)305 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
306 const union sctp_addr *paddr)
307 {
308 struct list_head *pos;
309 struct sctp_sockaddr_entry *addr;
310 struct sctp_bind_addr *bp;
311
312 sctp_read_lock(&ep->base.addr_lock);
313 bp = &ep->base.bind_addr;
314 list_for_each(pos, &bp->address_list) {
315 addr = list_entry(pos, struct sctp_sockaddr_entry, list);
316 if (sctp_has_association(&addr->a, paddr)) {
317 sctp_read_unlock(&ep->base.addr_lock);
318 return 1;
319 }
320 }
321 sctp_read_unlock(&ep->base.addr_lock);
322
323 return 0;
324 }
325
326 /* Do delayed input processing. This is scheduled by sctp_rcv().
327 * This may be called on BH or task time.
328 */
sctp_endpoint_bh_rcv(struct sctp_endpoint * ep)329 static void sctp_endpoint_bh_rcv(struct sctp_endpoint *ep)
330 {
331 struct sctp_association *asoc;
332 struct sock *sk;
333 struct sctp_transport *transport;
334 struct sctp_chunk *chunk;
335 struct sctp_inq *inqueue;
336 sctp_subtype_t subtype;
337 sctp_state_t state;
338 int error = 0;
339
340 if (ep->base.dead)
341 return;
342
343 asoc = NULL;
344 inqueue = &ep->base.inqueue;
345 sk = ep->base.sk;
346
347 while (NULL != (chunk = sctp_inq_pop(inqueue))) {
348 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
349
350 /* We might have grown an association since last we
351 * looked, so try again.
352 *
353 * This happens when we've just processed our
354 * COOKIE-ECHO chunk.
355 */
356 if (NULL == chunk->asoc) {
357 asoc = sctp_endpoint_lookup_assoc(ep,
358 sctp_source(chunk),
359 &transport);
360 chunk->asoc = asoc;
361 chunk->transport = transport;
362 }
363
364 state = asoc ? asoc->state : SCTP_STATE_CLOSED;
365
366 /* Remember where the last DATA chunk came from so we
367 * know where to send the SACK.
368 */
369 if (asoc && sctp_chunk_is_data(chunk))
370 asoc->peer.last_data_from = chunk->transport;
371 else
372 SCTP_INC_STATS(SctpInCtrlChunks);
373
374 if (chunk->transport)
375 chunk->transport->last_time_heard = jiffies;
376
377 error = sctp_do_sm(SCTP_EVENT_T_CHUNK, subtype, state,
378 ep, asoc, chunk, GFP_ATOMIC);
379
380 if (error && chunk)
381 chunk->pdiscard = 1;
382
383 /* Check to see if the endpoint is freed in response to
384 * the incoming chunk. If so, get out of the while loop.
385 */
386 if (!sctp_sk(sk)->ep)
387 break;
388 }
389 }
390