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

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