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, 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 <linux/crypto.h>
  46 #include <net/sock.h>
  47 #include <net/ipv6.h>
  48 #include <net/sctp/sctp.h>
  49 #include <net/sctp/sm.h>
  50
  51 /* Forward declarations for internal helpers. */
  52 static void sctp_endpoint_bh_rcv(struct work_struct *work);
  53
  54 /*
  55  * Initialize the base fields of the endpoint structure.
  56  */
  57 static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep,
  58                                                 struct sock *sk,
  59                                                 gfp_t gfp)
  60 {
  61         struct net *net = sock_net(sk);
  62         struct sctp_hmac_algo_param *auth_hmacs = NULL;
  63         struct sctp_chunks_param *auth_chunks = NULL;
  64         struct sctp_shared_key *null_key;
  65         int err;
  66
  67         ep->digest = kzalloc(SCTP_SIGNATURE_SIZE, gfp);
  68         if (!ep->digest)
  69                 return NULL;
  70
  71         if (net->sctp.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 do a linear search of the associations for this endpoint.
 317  * We return the matching transport address too.
 318  */
 319 static 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_association *tmp;
 326         struct sctp_transport *t = NULL;
 327         struct sctp_hashbucket *head;
 328         struct sctp_ep_common *epb;
 329         int hash;
 330         int rport;
 331
 332         *transport = NULL;
 333
 334         /* If the local port is not set, there can't be any associations
 335          * on this endpoint.
 336          */
 337         if (!ep->base.bind_addr.port)
 338                 goto out;
 339
 340         rport = ntohs(paddr->v4.sin_port);
 341
 342         hash = sctp_assoc_hashfn(sock_net(ep->base.sk), ep->base.bind_addr.port,
 343                                  rport);
 344         head = &sctp_assoc_hashtable[hash];
 345         read_lock(&head->lock);
 346         sctp_for_each_hentry(epb, &head->chain) {
 347                 tmp = sctp_assoc(epb);
 348                 if (tmp->ep != ep || rport != tmp->peer.port)
 349                         continue;
 350
 351                 t = sctp_assoc_lookup_paddr(tmp, paddr);
 352                 if (t) {
 353                         asoc = tmp;
 354                         *transport = t;
 355                         break;
 356                 }
 357         }
 358         read_unlock(&head->lock);
 359 out:
 360         return asoc;
 361 }
 362
 363 /* Lookup association on an endpoint based on a peer address.  BH-safe.  */
 364 struct sctp_association *sctp_endpoint_lookup_assoc(
 365         const struct sctp_endpoint *ep,
 366         const union sctp_addr *paddr,
 367         struct sctp_transport **transport)
 368 {
 369         struct sctp_association *asoc;
 370
 371         sctp_local_bh_disable();
 372         asoc = __sctp_endpoint_lookup_assoc(ep, paddr, transport);
 373         sctp_local_bh_enable();
 374
 375         return asoc;
 376 }
 377
 378 /* Look for any peeled off association from the endpoint that matches the
 379  * given peer address.
 380  */
 381 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
 382                                 const union sctp_addr *paddr)
 383 {
 384         struct sctp_sockaddr_entry *addr;
 385         struct sctp_bind_addr *bp;
 386         struct net *net = sock_net(ep->base.sk);
 387
 388         bp = &ep->base.bind_addr;
 389         /* This function is called with the socket lock held,
 390          * so the address_list can not change.
 391          */
 392         list_for_each_entry(addr, &bp->address_list, list) {
 393                 if (sctp_has_association(net, &addr->a, paddr))
 394                         return 1;
 395         }
 396
 397         return 0;
 398 }
 399
 400 /* Do delayed input processing.  This is scheduled by sctp_rcv().
 401  * This may be called on BH or task time.
 402  */
 403 static void sctp_endpoint_bh_rcv(struct work_struct *work)
 404 {
 405         struct sctp_endpoint *ep =
 406                 container_of(work, struct sctp_endpoint,
 407                              base.inqueue.immediate);
 408         struct sctp_association *asoc;
 409         struct sock *sk;
 410         struct net *net;
 411         struct sctp_transport *transport;
 412         struct sctp_chunk *chunk;
 413         struct sctp_inq *inqueue;
 414         sctp_subtype_t subtype;
 415         sctp_state_t state;
 416         int error = 0;
 417         int first_time = 1;     /* is this the first time through the loop */
 418
 419         if (ep->base.dead)
 420                 return;
 421
 422         asoc = NULL;
 423         inqueue = &ep->base.inqueue;
 424         sk = ep->base.sk;
 425         net = sock_net(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(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS);
 478                         if (asoc)
 479                                 asoc->stats.ictrlchunks++;
 480                 }
 481
 482                 if (chunk->transport)
 483                         chunk->transport->last_time_heard = jiffies;
 484
 485                 error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state,
 486                                    ep, asoc, chunk, GFP_ATOMIC);
 487
 488                 if (error && chunk)
 489                         chunk->pdiscard = 1;
 490
 491                 /* Check to see if the endpoint is freed in response to
 492                  * the incoming chunk. If so, get out of the while loop.
 493                  */
 494                 if (!sctp_sk(sk)->ep)
 495                         break;
 496
 497                 if (first_time)
 498                         first_time = 0;
 499         }
 500 }