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Linux/net/sctp/endpointola.c

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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(*auth_hmacs) +
 77                                      sizeof(__u16) * SCTP_AUTH_NUM_HMACS, gfp);
 78                 if (!auth_hmacs)
 79                         goto nomem;
 80 
 81                 auth_chunks = kzalloc(sizeof(*auth_chunks) +
 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(struct sctp_paramhdr) + 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 =
 99                                         htons(sizeof(struct sctp_paramhdr));
100 
101                 /* If the Add-IP functionality is enabled, we must
102                  * authenticate, ASCONF and ASCONF-ACK chunks
103                  */
104                 if (net->sctp.addip_enable) {
105                         auth_chunks->chunks[0] = SCTP_CID_ASCONF;
106                         auth_chunks->chunks[1] = SCTP_CID_ASCONF_ACK;
107                         auth_chunks->param_hdr.length =
108                                         htons(sizeof(struct sctp_paramhdr) + 2);
109                 }
110         }
111 
112         /* Initialize the base structure. */
113         /* What type of endpoint are we?  */
114         ep->base.type = SCTP_EP_TYPE_SOCKET;
115 
116         /* Initialize the basic object fields. */
117         refcount_set(&ep->base.refcnt, 1);
118         ep->base.dead = false;
119 
120         /* Create an input queue.  */
121         sctp_inq_init(&ep->base.inqueue);
122 
123         /* Set its top-half handler */
124         sctp_inq_set_th_handler(&ep->base.inqueue, sctp_endpoint_bh_rcv);
125 
126         /* Initialize the bind addr area */
127         sctp_bind_addr_init(&ep->base.bind_addr, 0);
128 
129         /* Remember who we are attached to.  */
130         ep->base.sk = sk;
131         sock_hold(ep->base.sk);
132 
133         /* Create the lists of associations.  */
134         INIT_LIST_HEAD(&ep->asocs);
135 
136         /* Use SCTP specific send buffer space queues.  */
137         ep->sndbuf_policy = net->sctp.sndbuf_policy;
138 
139         sk->sk_data_ready = sctp_data_ready;
140         sk->sk_write_space = sctp_write_space;
141         sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
142 
143         /* Get the receive buffer policy for this endpoint */
144         ep->rcvbuf_policy = net->sctp.rcvbuf_policy;
145 
146         /* Initialize the secret key used with cookie. */
147         get_random_bytes(ep->secret_key, sizeof(ep->secret_key));
148 
149         /* SCTP-AUTH extensions*/
150         INIT_LIST_HEAD(&ep->endpoint_shared_keys);
151         null_key = sctp_auth_shkey_create(0, gfp);
152         if (!null_key)
153                 goto nomem;
154 
155         list_add(&null_key->key_list, &ep->endpoint_shared_keys);
156 
157         /* Allocate and initialize transorms arrays for supported HMACs. */
158         err = sctp_auth_init_hmacs(ep, gfp);
159         if (err)
160                 goto nomem_hmacs;
161 
162         /* Add the null key to the endpoint shared keys list and
163          * set the hmcas and chunks pointers.
164          */
165         ep->auth_hmacs_list = auth_hmacs;
166         ep->auth_chunk_list = auth_chunks;
167         ep->prsctp_enable = net->sctp.prsctp_enable;
168         ep->reconf_enable = net->sctp.reconf_enable;
169 
170         return ep;
171 
172 nomem_hmacs:
173         sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
174 nomem:
175         /* Free all allocations */
176         kfree(auth_hmacs);
177         kfree(auth_chunks);
178         kfree(ep->digest);
179         return NULL;
180 
181 }
182 
183 /* Create a sctp_endpoint with all that boring stuff initialized.
184  * Returns NULL if there isn't enough memory.
185  */
186 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp)
187 {
188         struct sctp_endpoint *ep;
189 
190         /* Build a local endpoint. */
191         ep = kzalloc(sizeof(*ep), gfp);
192         if (!ep)
193                 goto fail;
194 
195         if (!sctp_endpoint_init(ep, sk, gfp))
196                 goto fail_init;
197 
198         SCTP_DBG_OBJCNT_INC(ep);
199         return ep;
200 
201 fail_init:
202         kfree(ep);
203 fail:
204         return NULL;
205 }
206 
207 /* Add an association to an endpoint.  */
208 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep,
209                             struct sctp_association *asoc)
210 {
211         struct sock *sk = ep->base.sk;
212 
213         /* If this is a temporary association, don't bother
214          * since we'll be removing it shortly and don't
215          * want anyone to find it anyway.
216          */
217         if (asoc->temp)
218                 return;
219 
220         /* Now just add it to our list of asocs */
221         list_add_tail(&asoc->asocs, &ep->asocs);
222 
223         /* Increment the backlog value for a TCP-style listening socket. */
224         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
225                 sk->sk_ack_backlog++;
226 }
227 
228 /* Free the endpoint structure.  Delay cleanup until
229  * all users have released their reference count on this structure.
230  */
231 void sctp_endpoint_free(struct sctp_endpoint *ep)
232 {
233         ep->base.dead = true;
234 
235         inet_sk_set_state(ep->base.sk, SCTP_SS_CLOSED);
236 
237         /* Unlink this endpoint, so we can't find it again! */
238         sctp_unhash_endpoint(ep);
239 
240         sctp_endpoint_put(ep);
241 }
242 
243 /* Final destructor for endpoint.  */
244 static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
245 {
246         struct sock *sk;
247 
248         if (unlikely(!ep->base.dead)) {
249                 WARN(1, "Attempt to destroy undead endpoint %p!\n", ep);
250                 return;
251         }
252 
253         /* Free the digest buffer */
254         kfree(ep->digest);
255 
256         /* SCTP-AUTH: Free up AUTH releated data such as shared keys
257          * chunks and hmacs arrays that were allocated
258          */
259         sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
260         kfree(ep->auth_hmacs_list);
261         kfree(ep->auth_chunk_list);
262 
263         /* AUTH - Free any allocated HMAC transform containers */
264         sctp_auth_destroy_hmacs(ep->auth_hmacs);
265 
266         /* Cleanup. */
267         sctp_inq_free(&ep->base.inqueue);
268         sctp_bind_addr_free(&ep->base.bind_addr);
269 
270         memset(ep->secret_key, 0, sizeof(ep->secret_key));
271 
272         sk = ep->base.sk;
273         /* Remove and free the port */
274         if (sctp_sk(sk)->bind_hash)
275                 sctp_put_port(sk);
276 
277         sctp_sk(sk)->ep = NULL;
278         /* Give up our hold on the sock */
279         sock_put(sk);
280 
281         kfree(ep);
282         SCTP_DBG_OBJCNT_DEC(ep);
283 }
284 
285 /* Hold a reference to an endpoint. */
286 void sctp_endpoint_hold(struct sctp_endpoint *ep)
287 {
288         refcount_inc(&ep->base.refcnt);
289 }
290 
291 /* Release a reference to an endpoint and clean up if there are
292  * no more references.
293  */
294 void sctp_endpoint_put(struct sctp_endpoint *ep)
295 {
296         if (refcount_dec_and_test(&ep->base.refcnt))
297                 sctp_endpoint_destroy(ep);
298 }
299 
300 /* Is this the endpoint we are looking for?  */
301 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
302                                                struct net *net,
303                                                const union sctp_addr *laddr)
304 {
305         struct sctp_endpoint *retval = NULL;
306 
307         if ((htons(ep->base.bind_addr.port) == laddr->v4.sin_port) &&
308             net_eq(sock_net(ep->base.sk), net)) {
309                 if (sctp_bind_addr_match(&ep->base.bind_addr, laddr,
310                                          sctp_sk(ep->base.sk)))
311                         retval = ep;
312         }
313 
314         return retval;
315 }
316 
317 /* Find the association that goes with this chunk.
318  * We lookup the transport from hashtable at first, then get association
319  * through t->assoc.
320  */
321 struct sctp_association *sctp_endpoint_lookup_assoc(
322         const struct sctp_endpoint *ep,
323         const union sctp_addr *paddr,
324         struct sctp_transport **transport)
325 {
326         struct sctp_association *asoc = NULL;
327         struct sctp_transport *t;
328 
329         *transport = NULL;
330 
331         /* If the local port is not set, there can't be any associations
332          * on this endpoint.
333          */
334         if (!ep->base.bind_addr.port)
335                 return NULL;
336 
337         rcu_read_lock();
338         t = sctp_epaddr_lookup_transport(ep, paddr);
339         if (!t)
340                 goto out;
341 
342         *transport = t;
343         asoc = t->asoc;
344 out:
345         rcu_read_unlock();
346         return asoc;
347 }
348 
349 /* Look for any peeled off association from the endpoint that matches the
350  * given peer address.
351  */
352 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
353                                 const union sctp_addr *paddr)
354 {
355         struct sctp_sockaddr_entry *addr;
356         struct sctp_bind_addr *bp;
357         struct net *net = sock_net(ep->base.sk);
358 
359         bp = &ep->base.bind_addr;
360         /* This function is called with the socket lock held,
361          * so the address_list can not change.
362          */
363         list_for_each_entry(addr, &bp->address_list, list) {
364                 if (sctp_has_association(net, &addr->a, paddr))
365                         return 1;
366         }
367 
368         return 0;
369 }
370 
371 /* Do delayed input processing.  This is scheduled by sctp_rcv().
372  * This may be called on BH or task time.
373  */
374 static void sctp_endpoint_bh_rcv(struct work_struct *work)
375 {
376         struct sctp_endpoint *ep =
377                 container_of(work, struct sctp_endpoint,
378                              base.inqueue.immediate);
379         struct sctp_association *asoc;
380         struct sock *sk;
381         struct net *net;
382         struct sctp_transport *transport;
383         struct sctp_chunk *chunk;
384         struct sctp_inq *inqueue;
385         union sctp_subtype subtype;
386         enum sctp_state state;
387         int error = 0;
388         int first_time = 1;     /* is this the first time through the loop */
389 
390         if (ep->base.dead)
391                 return;
392 
393         asoc = NULL;
394         inqueue = &ep->base.inqueue;
395         sk = ep->base.sk;
396         net = sock_net(sk);
397 
398         while (NULL != (chunk = sctp_inq_pop(inqueue))) {
399                 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
400 
401                 /* If the first chunk in the packet is AUTH, do special
402                  * processing specified in Section 6.3 of SCTP-AUTH spec
403                  */
404                 if (first_time && (subtype.chunk == SCTP_CID_AUTH)) {
405                         struct sctp_chunkhdr *next_hdr;
406 
407                         next_hdr = sctp_inq_peek(inqueue);
408                         if (!next_hdr)
409                                 goto normal;
410 
411                         /* If the next chunk is COOKIE-ECHO, skip the AUTH
412                          * chunk while saving a pointer to it so we can do
413                          * Authentication later (during cookie-echo
414                          * processing).
415                          */
416                         if (next_hdr->type == SCTP_CID_COOKIE_ECHO) {
417                                 chunk->auth_chunk = skb_clone(chunk->skb,
418                                                                 GFP_ATOMIC);
419                                 chunk->auth = 1;
420                                 continue;
421                         }
422                 }
423 normal:
424                 /* We might have grown an association since last we
425                  * looked, so try again.
426                  *
427                  * This happens when we've just processed our
428                  * COOKIE-ECHO chunk.
429                  */
430                 if (NULL == chunk->asoc) {
431                         asoc = sctp_endpoint_lookup_assoc(ep,
432                                                           sctp_source(chunk),
433                                                           &transport);
434                         chunk->asoc = asoc;
435                         chunk->transport = transport;
436                 }
437 
438                 state = asoc ? asoc->state : SCTP_STATE_CLOSED;
439                 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
440                         continue;
441 
442                 /* Remember where the last DATA chunk came from so we
443                  * know where to send the SACK.
444                  */
445                 if (asoc && sctp_chunk_is_data(chunk))
446                         asoc->peer.last_data_from = chunk->transport;
447                 else {
448                         SCTP_INC_STATS(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS);
449                         if (asoc)
450                                 asoc->stats.ictrlchunks++;
451                 }
452 
453                 if (chunk->transport)
454                         chunk->transport->last_time_heard = ktime_get();
455 
456                 error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state,
457                                    ep, asoc, chunk, GFP_ATOMIC);
458 
459                 if (error && chunk)
460                         chunk->pdiscard = 1;
461 
462                 /* Check to see if the endpoint is freed in response to
463                  * the incoming chunk. If so, get out of the while loop.
464                  */
465                 if (!sctp_sk(sk)->ep)
466                         break;
467 
468                 if (first_time)
469                         first_time = 0;
470         }
471 }
472 

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