net/sctp/endpointola.c

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