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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, 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 net *net = sock_net(sk);
 69         struct sctp_hmac_algo_param *auth_hmacs = NULL;
 70         struct sctp_chunks_param *auth_chunks = NULL;
 71         struct sctp_shared_key *null_key;
 72         int err;
 73 
 74         ep->digest = kzalloc(SCTP_SIGNATURE_SIZE, gfp);
 75         if (!ep->digest)
 76                 return NULL;
 77 
 78         if (net->sctp.auth_enable) {
 79                 /* Allocate space for HMACS and CHUNKS authentication
 80                  * variables.  There are arrays that we encode directly
 81                  * into parameters to make the rest of the operations easier.
 82                  */
 83                 auth_hmacs = kzalloc(sizeof(sctp_hmac_algo_param_t) +
 84                                 sizeof(__u16) * SCTP_AUTH_NUM_HMACS, gfp);
 85                 if (!auth_hmacs)
 86                         goto nomem;
 87 
 88                 auth_chunks = kzalloc(sizeof(sctp_chunks_param_t) +
 89                                         SCTP_NUM_CHUNK_TYPES, gfp);
 90                 if (!auth_chunks)
 91                         goto nomem;
 92 
 93                 /* Initialize the HMACS parameter.
 94                  * SCTP-AUTH: Section 3.3
 95                  *    Every endpoint supporting SCTP chunk authentication MUST
 96                  *    support the HMAC based on the SHA-1 algorithm.
 97                  */
 98                 auth_hmacs->param_hdr.type = SCTP_PARAM_HMAC_ALGO;
 99                 auth_hmacs->param_hdr.length =
100                                         htons(sizeof(sctp_paramhdr_t) + 2);
101                 auth_hmacs->hmac_ids[0] = htons(SCTP_AUTH_HMAC_ID_SHA1);
102 
103                 /* Initialize the CHUNKS parameter */
104                 auth_chunks->param_hdr.type = SCTP_PARAM_CHUNKS;
105                 auth_chunks->param_hdr.length = htons(sizeof(sctp_paramhdr_t));
106 
107                 /* If the Add-IP functionality is enabled, we must
108                  * authenticate, ASCONF and ASCONF-ACK chunks
109                  */
110                 if (net->sctp.addip_enable) {
111                         auth_chunks->chunks[0] = SCTP_CID_ASCONF;
112                         auth_chunks->chunks[1] = SCTP_CID_ASCONF_ACK;
113                         auth_chunks->param_hdr.length =
114                                         htons(sizeof(sctp_paramhdr_t) + 2);
115                 }
116         }
117 
118         /* Initialize the base structure. */
119         /* What type of endpoint are we?  */
120         ep->base.type = SCTP_EP_TYPE_SOCKET;
121 
122         /* Initialize the basic object fields. */
123         atomic_set(&ep->base.refcnt, 1);
124         ep->base.dead = false;
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 = net->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 = net->sctp.rcvbuf_policy;
151 
152         /* Initialize the secret key used with cookie. */
153         get_random_bytes(ep->secret_key, sizeof(ep->secret_key));
154 
155         /* SCTP-AUTH extensions*/
156         INIT_LIST_HEAD(&ep->endpoint_shared_keys);
157         null_key = sctp_auth_shkey_create(0, gfp);
158         if (!null_key)
159                 goto nomem;
160 
161         list_add(&null_key->key_list, &ep->endpoint_shared_keys);
162 
163         /* Allocate and initialize transorms arrays for supported HMACs. */
164         err = sctp_auth_init_hmacs(ep, gfp);
165         if (err)
166                 goto nomem_hmacs;
167 
168         /* Add the null key to the endpoint shared keys list and
169          * set the hmcas and chunks pointers.
170          */
171         ep->auth_hmacs_list = auth_hmacs;
172         ep->auth_chunk_list = auth_chunks;
173 
174         return ep;
175 
176 nomem_hmacs:
177         sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
178 nomem:
179         /* Free all allocations */
180         kfree(auth_hmacs);
181         kfree(auth_chunks);
182         kfree(ep->digest);
183         return NULL;
184 
185 }
186 
187 /* Create a sctp_endpoint with all that boring stuff initialized.
188  * Returns NULL if there isn't enough memory.
189  */
190 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp)
191 {
192         struct sctp_endpoint *ep;
193 
194         /* Build a local endpoint. */
195         ep = kzalloc(sizeof(*ep), gfp);
196         if (!ep)
197                 goto fail;
198 
199         if (!sctp_endpoint_init(ep, sk, gfp))
200                 goto fail_init;
201 
202         SCTP_DBG_OBJCNT_INC(ep);
203         return ep;
204 
205 fail_init:
206         kfree(ep);
207 fail:
208         return NULL;
209 }
210 
211 /* Add an association to an endpoint.  */
212 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep,
213                             struct sctp_association *asoc)
214 {
215         struct sock *sk = ep->base.sk;
216 
217         /* If this is a temporary association, don't bother
218          * since we'll be removing it shortly and don't
219          * want anyone to find it anyway.
220          */
221         if (asoc->temp)
222                 return;
223 
224         /* Now just add it to our list of asocs */
225         list_add_tail(&asoc->asocs, &ep->asocs);
226 
227         /* Increment the backlog value for a TCP-style listening socket. */
228         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
229                 sk->sk_ack_backlog++;
230 }
231 
232 /* Free the endpoint structure.  Delay cleanup until
233  * all users have released their reference count on this structure.
234  */
235 void sctp_endpoint_free(struct sctp_endpoint *ep)
236 {
237         ep->base.dead = true;
238 
239         ep->base.sk->sk_state = SCTP_SS_CLOSED;
240 
241         /* Unlink this endpoint, so we can't find it again! */
242         sctp_unhash_endpoint(ep);
243 
244         sctp_endpoint_put(ep);
245 }
246 
247 /* Final destructor for endpoint.  */
248 static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
249 {
250         struct sock *sk;
251 
252         if (unlikely(!ep->base.dead)) {
253                 WARN(1, "Attempt to destroy undead endpoint %p!\n", ep);
254                 return;
255         }
256 
257         /* Free the digest buffer */
258         kfree(ep->digest);
259 
260         /* SCTP-AUTH: Free up AUTH releated data such as shared keys
261          * chunks and hmacs arrays that were allocated
262          */
263         sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
264         kfree(ep->auth_hmacs_list);
265         kfree(ep->auth_chunk_list);
266 
267         /* AUTH - Free any allocated HMAC transform containers */
268         sctp_auth_destroy_hmacs(ep->auth_hmacs);
269 
270         /* Cleanup. */
271         sctp_inq_free(&ep->base.inqueue);
272         sctp_bind_addr_free(&ep->base.bind_addr);
273 
274         memset(ep->secret_key, 0, sizeof(ep->secret_key));
275 
276         /* Give up our hold on the sock. */
277         sk = ep->base.sk;
278         if (sk != NULL) {
279                 /* Remove and free the port */
280                 if (sctp_sk(sk)->bind_hash)
281                         sctp_put_port(sk);
282 
283                 sock_put(sk);
284         }
285 
286         kfree(ep);
287         SCTP_DBG_OBJCNT_DEC(ep);
288 }
289 
290 /* Hold a reference to an endpoint. */
291 void sctp_endpoint_hold(struct sctp_endpoint *ep)
292 {
293         atomic_inc(&ep->base.refcnt);
294 }
295 
296 /* Release a reference to an endpoint and clean up if there are
297  * no more references.
298  */
299 void sctp_endpoint_put(struct sctp_endpoint *ep)
300 {
301         if (atomic_dec_and_test(&ep->base.refcnt))
302                 sctp_endpoint_destroy(ep);
303 }
304 
305 /* Is this the endpoint we are looking for?  */
306 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
307                                                struct net *net,
308                                                const union sctp_addr *laddr)
309 {
310         struct sctp_endpoint *retval = NULL;
311 
312         if ((htons(ep->base.bind_addr.port) == laddr->v4.sin_port) &&
313             net_eq(sock_net(ep->base.sk), net)) {
314                 if (sctp_bind_addr_match(&ep->base.bind_addr, laddr,
315                                          sctp_sk(ep->base.sk)))
316                         retval = ep;
317         }
318 
319         return retval;
320 }
321 
322 /* Find the association that goes with this chunk.
323  * We do a linear search of the associations for this endpoint.
324  * We return the matching transport address too.
325  */
326 static struct sctp_association *__sctp_endpoint_lookup_assoc(
327         const struct sctp_endpoint *ep,
328         const union sctp_addr *paddr,
329         struct sctp_transport **transport)
330 {
331         struct sctp_association *asoc = NULL;
332         struct sctp_association *tmp;
333         struct sctp_transport *t = NULL;
334         struct sctp_hashbucket *head;
335         struct sctp_ep_common *epb;
336         int hash;
337         int rport;
338 
339         *transport = NULL;
340 
341         /* If the local port is not set, there can't be any associations
342          * on this endpoint.
343          */
344         if (!ep->base.bind_addr.port)
345                 goto out;
346 
347         rport = ntohs(paddr->v4.sin_port);
348 
349         hash = sctp_assoc_hashfn(sock_net(ep->base.sk), ep->base.bind_addr.port,
350                                  rport);
351         head = &sctp_assoc_hashtable[hash];
352         read_lock(&head->lock);
353         sctp_for_each_hentry(epb, &head->chain) {
354                 tmp = sctp_assoc(epb);
355                 if (tmp->ep != ep || rport != tmp->peer.port)
356                         continue;
357 
358                 t = sctp_assoc_lookup_paddr(tmp, paddr);
359                 if (t) {
360                         asoc = tmp;
361                         *transport = t;
362                         break;
363                 }
364         }
365         read_unlock(&head->lock);
366 out:
367         return asoc;
368 }
369 
370 /* Lookup association on an endpoint based on a peer address.  BH-safe.  */
371 struct sctp_association *sctp_endpoint_lookup_assoc(
372         const struct sctp_endpoint *ep,
373         const union sctp_addr *paddr,
374         struct sctp_transport **transport)
375 {
376         struct sctp_association *asoc;
377 
378         sctp_local_bh_disable();
379         asoc = __sctp_endpoint_lookup_assoc(ep, paddr, transport);
380         sctp_local_bh_enable();
381 
382         return asoc;
383 }
384 
385 /* Look for any peeled off association from the endpoint that matches the
386  * given peer address.
387  */
388 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
389                                 const union sctp_addr *paddr)
390 {
391         struct sctp_sockaddr_entry *addr;
392         struct sctp_bind_addr *bp;
393         struct net *net = sock_net(ep->base.sk);
394 
395         bp = &ep->base.bind_addr;
396         /* This function is called with the socket lock held,
397          * so the address_list can not change.
398          */
399         list_for_each_entry(addr, &bp->address_list, list) {
400                 if (sctp_has_association(net, &addr->a, paddr))
401                         return 1;
402         }
403 
404         return 0;
405 }
406 
407 /* Do delayed input processing.  This is scheduled by sctp_rcv().
408  * This may be called on BH or task time.
409  */
410 static void sctp_endpoint_bh_rcv(struct work_struct *work)
411 {
412         struct sctp_endpoint *ep =
413                 container_of(work, struct sctp_endpoint,
414                              base.inqueue.immediate);
415         struct sctp_association *asoc;
416         struct sock *sk;
417         struct net *net;
418         struct sctp_transport *transport;
419         struct sctp_chunk *chunk;
420         struct sctp_inq *inqueue;
421         sctp_subtype_t subtype;
422         sctp_state_t state;
423         int error = 0;
424         int first_time = 1;     /* is this the first time through the loop */
425 
426         if (ep->base.dead)
427                 return;
428 
429         asoc = NULL;
430         inqueue = &ep->base.inqueue;
431         sk = ep->base.sk;
432         net = sock_net(sk);
433 
434         while (NULL != (chunk = sctp_inq_pop(inqueue))) {
435                 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
436 
437                 /* If the first chunk in the packet is AUTH, do special
438                  * processing specified in Section 6.3 of SCTP-AUTH spec
439                  */
440                 if (first_time && (subtype.chunk == SCTP_CID_AUTH)) {
441                         struct sctp_chunkhdr *next_hdr;
442 
443                         next_hdr = sctp_inq_peek(inqueue);
444                         if (!next_hdr)
445                                 goto normal;
446 
447                         /* If the next chunk is COOKIE-ECHO, skip the AUTH
448                          * chunk while saving a pointer to it so we can do
449                          * Authentication later (during cookie-echo
450                          * processing).
451                          */
452                         if (next_hdr->type == SCTP_CID_COOKIE_ECHO) {
453                                 chunk->auth_chunk = skb_clone(chunk->skb,
454                                                                 GFP_ATOMIC);
455                                 chunk->auth = 1;
456                                 continue;
457                         }
458                 }
459 normal:
460                 /* We might have grown an association since last we
461                  * looked, so try again.
462                  *
463                  * This happens when we've just processed our
464                  * COOKIE-ECHO chunk.
465                  */
466                 if (NULL == chunk->asoc) {
467                         asoc = sctp_endpoint_lookup_assoc(ep,
468                                                           sctp_source(chunk),
469                                                           &transport);
470                         chunk->asoc = asoc;
471                         chunk->transport = transport;
472                 }
473 
474                 state = asoc ? asoc->state : SCTP_STATE_CLOSED;
475                 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
476                         continue;
477 
478                 /* Remember where the last DATA chunk came from so we
479                  * know where to send the SACK.
480                  */
481                 if (asoc && sctp_chunk_is_data(chunk))
482                         asoc->peer.last_data_from = chunk->transport;
483                 else {
484                         SCTP_INC_STATS(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS);
485                         if (asoc)
486                                 asoc->stats.ictrlchunks++;
487                 }
488 
489                 if (chunk->transport)
490                         chunk->transport->last_time_heard = jiffies;
491 
492                 error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state,
493                                    ep, asoc, chunk, GFP_ATOMIC);
494 
495                 if (error && chunk)
496                         chunk->pdiscard = 1;
497 
498                 /* Check to see if the endpoint is freed in response to
499                  * the incoming chunk. If so, get out of the while loop.
500                  */
501                 if (!sctp_sk(sk)->ep)
502                         break;
503 
504                 if (first_time)
505                         first_time = 0;
506         }
507 }
508 

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