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 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 = t_new(struct sctp_endpoint, gfp);
 196         if (!ep)
 197                 goto fail;
 198         if (!sctp_endpoint_init(ep, sk, gfp))
 199                 goto fail_init;
 200
 201         SCTP_DBG_OBJCNT_INC(ep);
 202         return ep;
 203
 204 fail_init:
 205         kfree(ep);
 206 fail:
 207         return NULL;
 208 }
 209
 210 /* Add an association to an endpoint.  */
 211 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep,
 212                             struct sctp_association *asoc)
 213 {
 214         struct sock *sk = ep->base.sk;
 215
 216         /* If this is a temporary association, don't bother
 217          * since we'll be removing it shortly and don't
 218          * want anyone to find it anyway.
 219          */
 220         if (asoc->temp)
 221                 return;
 222
 223         /* Now just add it to our list of asocs */
 224         list_add_tail(&asoc->asocs, &ep->asocs);
 225
 226         /* Increment the backlog value for a TCP-style listening socket. */
 227         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
 228                 sk->sk_ack_backlog++;
 229 }
 230
 231 /* Free the endpoint structure.  Delay cleanup until
 232  * all users have released their reference count on this structure.
 233  */
 234 void sctp_endpoint_free(struct sctp_endpoint *ep)
 235 {
 236         ep->base.dead = true;
 237
 238         ep->base.sk->sk_state = SCTP_SS_CLOSED;
 239
 240         /* Unlink this endpoint, so we can't find it again! */
 241         sctp_unhash_endpoint(ep);
 242
 243         sctp_endpoint_put(ep);
 244 }
 245
 246 /* Final destructor for endpoint.  */
 247 static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
 248 {
 249         SCTP_ASSERT(ep->base.dead, "Endpoint is not dead", return);
 250
 251         /* Free up the HMAC transform. */
 252         crypto_free_hash(sctp_sk(ep->base.sk)->hmac);
 253
 254         /* Free the digest buffer */
 255         kfree(ep->digest);
 256
 257         /* SCTP-AUTH: Free up AUTH releated data such as shared keys
 258          * chunks and hmacs arrays that were allocated
 259          */
 260         sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
 261         kfree(ep->auth_hmacs_list);
 262         kfree(ep->auth_chunk_list);
 263
 264         /* AUTH - Free any allocated HMAC transform containers */
 265         sctp_auth_destroy_hmacs(ep->auth_hmacs);
 266
 267         /* Cleanup. */
 268         sctp_inq_free(&ep->base.inqueue);
 269         sctp_bind_addr_free(&ep->base.bind_addr);
 270
 271         memset(ep->secret_key, 0, sizeof(ep->secret_key));
 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         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         atomic_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 (atomic_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 do a linear search of the associations for this endpoint.
 319  * We return the matching transport address too.
 320  */
 321 static 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_association *tmp;
 328         struct sctp_transport *t = NULL;
 329         struct sctp_hashbucket *head;
 330         struct sctp_ep_common *epb;
 331         int hash;
 332         int rport;
 333
 334         *transport = NULL;
 335
 336         /* If the local port is not set, there can't be any associations
 337          * on this endpoint.
 338          */
 339         if (!ep->base.bind_addr.port)
 340                 goto out;
 341
 342         rport = ntohs(paddr->v4.sin_port);
 343
 344         hash = sctp_assoc_hashfn(sock_net(ep->base.sk), ep->base.bind_addr.port,
 345                                  rport);
 346         head = &sctp_assoc_hashtable[hash];
 347         read_lock(&head->lock);
 348         sctp_for_each_hentry(epb, &head->chain) {
 349                 tmp = sctp_assoc(epb);
 350                 if (tmp->ep != ep || rport != tmp->peer.port)
 351                         continue;
 352
 353                 t = sctp_assoc_lookup_paddr(tmp, paddr);
 354                 if (t) {
 355                         asoc = tmp;
 356                         *transport = t;
 357                         break;
 358                 }
 359         }
 360         read_unlock(&head->lock);
 361 out:
 362         return asoc;
 363 }
 364
 365 /* Lookup association on an endpoint based on a peer address.  BH-safe.  */
 366 struct sctp_association *sctp_endpoint_lookup_assoc(
 367         const struct sctp_endpoint *ep,
 368         const union sctp_addr *paddr,
 369         struct sctp_transport **transport)
 370 {
 371         struct sctp_association *asoc;
 372
 373         sctp_local_bh_disable();
 374         asoc = __sctp_endpoint_lookup_assoc(ep, paddr, transport);
 375         sctp_local_bh_enable();
 376
 377         return asoc;
 378 }
 379
 380 /* Look for any peeled off association from the endpoint that matches the
 381  * given peer address.
 382  */
 383 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
 384                                 const union sctp_addr *paddr)
 385 {
 386         struct sctp_sockaddr_entry *addr;
 387         struct sctp_bind_addr *bp;
 388         struct net *net = sock_net(ep->base.sk);
 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(net, &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 net *net;
 413         struct sctp_transport *transport;
 414         struct sctp_chunk *chunk;
 415         struct sctp_inq *inqueue;
 416         sctp_subtype_t subtype;
 417         sctp_state_t state;
 418         int error = 0;
 419         int first_time = 1;     /* is this the first time through the loop */
 420
 421         if (ep->base.dead)
 422                 return;
 423
 424         asoc = NULL;
 425         inqueue = &ep->base.inqueue;
 426         sk = ep->base.sk;
 427         net = sock_net(sk);
 428
 429         while (NULL != (chunk = sctp_inq_pop(inqueue))) {
 430                 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
 431
 432                 /* If the first chunk in the packet is AUTH, do special
 433                  * processing specified in Section 6.3 of SCTP-AUTH spec
 434                  */
 435                 if (first_time && (subtype.chunk == SCTP_CID_AUTH)) {
 436                         struct sctp_chunkhdr *next_hdr;
 437
 438                         next_hdr = sctp_inq_peek(inqueue);
 439                         if (!next_hdr)
 440                                 goto normal;
 441
 442                         /* If the next chunk is COOKIE-ECHO, skip the AUTH
 443                          * chunk while saving a pointer to it so we can do
 444                          * Authentication later (during cookie-echo
 445                          * processing).
 446                          */
 447                         if (next_hdr->type == SCTP_CID_COOKIE_ECHO) {
 448                                 chunk->auth_chunk = skb_clone(chunk->skb,
 449                                                                 GFP_ATOMIC);
 450                                 chunk->auth = 1;
 451                                 continue;
 452                         }
 453                 }
 454 normal:
 455                 /* We might have grown an association since last we
 456                  * looked, so try again.
 457                  *
 458                  * This happens when we've just processed our
 459                  * COOKIE-ECHO chunk.
 460                  */
 461                 if (NULL == chunk->asoc) {
 462                         asoc = sctp_endpoint_lookup_assoc(ep,
 463                                                           sctp_source(chunk),
 464                                                           &transport);
 465                         chunk->asoc = asoc;
 466                         chunk->transport = transport;
 467                 }
 468
 469                 state = asoc ? asoc->state : SCTP_STATE_CLOSED;
 470                 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
 471                         continue;
 472
 473                 /* Remember where the last DATA chunk came from so we
 474                  * know where to send the SACK.
 475                  */
 476                 if (asoc && sctp_chunk_is_data(chunk))
 477                         asoc->peer.last_data_from = chunk->transport;
 478                 else {
 479                         SCTP_INC_STATS(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS);
 480                         if (asoc)
 481                                 asoc->stats.ictrlchunks++;
 482                 }
 483
 484                 if (chunk->transport)
 485                         chunk->transport->last_time_heard = jiffies;
 486
 487                 error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state,
 488                                    ep, asoc, chunk, GFP_ATOMIC);
 489
 490                 if (error && chunk)
 491                         chunk->pdiscard = 1;
 492
 493                 /* Check to see if the endpoint is freed in response to
 494                  * the incoming chunk. If so, get out of the while loop.
 495                  */
 496                 if (!sctp_sk(sk)->ep)
 497                         break;
 498
 499                 if (first_time)
 500                         first_time = 0;
 501         }
 502 }