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 <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(*auth_hmacs) +
  77                                      sizeof(__u16) * SCTP_AUTH_NUM_HMACS, gfp);
  78                 if (!auth_hmacs)
  79                         goto nomem;
  80
  81                 auth_chunks = kzalloc(sizeof(*auth_chunks) +
  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(struct sctp_paramhdr) + 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 =
  99                                         htons(sizeof(struct sctp_paramhdr));
 100
 101                 /* If the Add-IP functionality is enabled, we must
 102                  * authenticate, ASCONF and ASCONF-ACK chunks
 103                  */
 104                 if (net->sctp.addip_enable) {
 105                         auth_chunks->chunks[0] = SCTP_CID_ASCONF;
 106                         auth_chunks->chunks[1] = SCTP_CID_ASCONF_ACK;
 107                         auth_chunks->param_hdr.length =
 108                                         htons(sizeof(struct sctp_paramhdr) + 2);
 109                 }
 110         }
 111
 112         /* Initialize the base structure. */
 113         /* What type of endpoint are we?  */
 114         ep->base.type = SCTP_EP_TYPE_SOCKET;
 115
 116         /* Initialize the basic object fields. */
 117         refcount_set(&ep->base.refcnt, 1);
 118         ep->base.dead = false;
 119
 120         /* Create an input queue.  */
 121         sctp_inq_init(&ep->base.inqueue);
 122
 123         /* Set its top-half handler */
 124         sctp_inq_set_th_handler(&ep->base.inqueue, sctp_endpoint_bh_rcv);
 125
 126         /* Initialize the bind addr area */
 127         sctp_bind_addr_init(&ep->base.bind_addr, 0);
 128
 129         /* Remember who we are attached to.  */
 130         ep->base.sk = sk;
 131         sock_hold(ep->base.sk);
 132
 133         /* Create the lists of associations.  */
 134         INIT_LIST_HEAD(&ep->asocs);
 135
 136         /* Use SCTP specific send buffer space queues.  */
 137         ep->sndbuf_policy = net->sctp.sndbuf_policy;
 138
 139         sk->sk_data_ready = sctp_data_ready;
 140         sk->sk_write_space = sctp_write_space;
 141         sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
 142
 143         /* Get the receive buffer policy for this endpoint */
 144         ep->rcvbuf_policy = net->sctp.rcvbuf_policy;
 145
 146         /* Initialize the secret key used with cookie. */
 147         get_random_bytes(ep->secret_key, sizeof(ep->secret_key));
 148
 149         /* SCTP-AUTH extensions*/
 150         INIT_LIST_HEAD(&ep->endpoint_shared_keys);
 151         null_key = sctp_auth_shkey_create(0, gfp);
 152         if (!null_key)
 153                 goto nomem;
 154
 155         list_add(&null_key->key_list, &ep->endpoint_shared_keys);
 156
 157         /* Allocate and initialize transorms arrays for supported HMACs. */
 158         err = sctp_auth_init_hmacs(ep, gfp);
 159         if (err)
 160                 goto nomem_hmacs;
 161
 162         /* Add the null key to the endpoint shared keys list and
 163          * set the hmcas and chunks pointers.
 164          */
 165         ep->auth_hmacs_list = auth_hmacs;
 166         ep->auth_chunk_list = auth_chunks;
 167         ep->prsctp_enable = net->sctp.prsctp_enable;
 168         ep->reconf_enable = net->sctp.reconf_enable;
 169
 170         return ep;
 171
 172 nomem_hmacs:
 173         sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
 174 nomem:
 175         /* Free all allocations */
 176         kfree(auth_hmacs);
 177         kfree(auth_chunks);
 178         kfree(ep->digest);
 179         return NULL;
 180
 181 }
 182
 183 /* Create a sctp_endpoint with all that boring stuff initialized.
 184  * Returns NULL if there isn't enough memory.
 185  */
 186 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp)
 187 {
 188         struct sctp_endpoint *ep;
 189
 190         /* Build a local endpoint. */
 191         ep = kzalloc(sizeof(*ep), gfp);
 192         if (!ep)
 193                 goto fail;
 194
 195         if (!sctp_endpoint_init(ep, sk, gfp))
 196                 goto fail_init;
 197
 198         SCTP_DBG_OBJCNT_INC(ep);
 199         return ep;
 200
 201 fail_init:
 202         kfree(ep);
 203 fail:
 204         return NULL;
 205 }
 206
 207 /* Add an association to an endpoint.  */
 208 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep,
 209                             struct sctp_association *asoc)
 210 {
 211         struct sock *sk = ep->base.sk;
 212
 213         /* If this is a temporary association, don't bother
 214          * since we'll be removing it shortly and don't
 215          * want anyone to find it anyway.
 216          */
 217         if (asoc->temp)
 218                 return;
 219
 220         /* Now just add it to our list of asocs */
 221         list_add_tail(&asoc->asocs, &ep->asocs);
 222
 223         /* Increment the backlog value for a TCP-style listening socket. */
 224         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
 225                 sk->sk_ack_backlog++;
 226 }
 227
 228 /* Free the endpoint structure.  Delay cleanup until
 229  * all users have released their reference count on this structure.
 230  */
 231 void sctp_endpoint_free(struct sctp_endpoint *ep)
 232 {
 233         ep->base.dead = true;
 234
 235         inet_sk_set_state(ep->base.sk, SCTP_SS_CLOSED);
 236
 237         /* Unlink this endpoint, so we can't find it again! */
 238         sctp_unhash_endpoint(ep);
 239
 240         sctp_endpoint_put(ep);
 241 }
 242
 243 /* Final destructor for endpoint.  */
 244 static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
 245 {
 246         struct sock *sk;
 247
 248         if (unlikely(!ep->base.dead)) {
 249                 WARN(1, "Attempt to destroy undead endpoint %p!\n", ep);
 250                 return;
 251         }
 252
 253         /* Free the digest buffer */
 254         kfree(ep->digest);
 255
 256         /* SCTP-AUTH: Free up AUTH releated data such as shared keys
 257          * chunks and hmacs arrays that were allocated
 258          */
 259         sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
 260         kfree(ep->auth_hmacs_list);
 261         kfree(ep->auth_chunk_list);
 262
 263         /* AUTH - Free any allocated HMAC transform containers */
 264         sctp_auth_destroy_hmacs(ep->auth_hmacs);
 265
 266         /* Cleanup. */
 267         sctp_inq_free(&ep->base.inqueue);
 268         sctp_bind_addr_free(&ep->base.bind_addr);
 269
 270         memset(ep->secret_key, 0, sizeof(ep->secret_key));
 271
 272         sk = ep->base.sk;
 273         /* Remove and free the port */
 274         if (sctp_sk(sk)->bind_hash)
 275                 sctp_put_port(sk);
 276
 277         sctp_sk(sk)->ep = NULL;
 278         /* Give up our hold on the sock */
 279         sock_put(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         refcount_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 (refcount_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 lookup the transport from hashtable at first, then get association
 319  * through t->assoc.
 320  */
 321 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_transport *t;
 328
 329         *transport = NULL;
 330
 331         /* If the local port is not set, there can't be any associations
 332          * on this endpoint.
 333          */
 334         if (!ep->base.bind_addr.port)
 335                 return NULL;
 336
 337         rcu_read_lock();
 338         t = sctp_epaddr_lookup_transport(ep, paddr);
 339         if (!t)
 340                 goto out;
 341
 342         *transport = t;
 343         asoc = t->asoc;
 344 out:
 345         rcu_read_unlock();
 346         return asoc;
 347 }
 348
 349 /* Look for any peeled off association from the endpoint that matches the
 350  * given peer address.
 351  */
 352 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
 353                                 const union sctp_addr *paddr)
 354 {
 355         struct sctp_sockaddr_entry *addr;
 356         struct sctp_bind_addr *bp;
 357         struct net *net = sock_net(ep->base.sk);
 358
 359         bp = &ep->base.bind_addr;
 360         /* This function is called with the socket lock held,
 361          * so the address_list can not change.
 362          */
 363         list_for_each_entry(addr, &bp->address_list, list) {
 364                 if (sctp_has_association(net, &addr->a, paddr))
 365                         return 1;
 366         }
 367
 368         return 0;
 369 }
 370
 371 /* Do delayed input processing.  This is scheduled by sctp_rcv().
 372  * This may be called on BH or task time.
 373  */
 374 static void sctp_endpoint_bh_rcv(struct work_struct *work)
 375 {
 376         struct sctp_endpoint *ep =
 377                 container_of(work, struct sctp_endpoint,
 378                              base.inqueue.immediate);
 379         struct sctp_association *asoc;
 380         struct sock *sk;
 381         struct net *net;
 382         struct sctp_transport *transport;
 383         struct sctp_chunk *chunk;
 384         struct sctp_inq *inqueue;
 385         union sctp_subtype subtype;
 386         enum sctp_state state;
 387         int error = 0;
 388         int first_time = 1;     /* is this the first time through the loop */
 389
 390         if (ep->base.dead)
 391                 return;
 392
 393         asoc = NULL;
 394         inqueue = &ep->base.inqueue;
 395         sk = ep->base.sk;
 396         net = sock_net(sk);
 397
 398         while (NULL != (chunk = sctp_inq_pop(inqueue))) {
 399                 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
 400
 401                 /* If the first chunk in the packet is AUTH, do special
 402                  * processing specified in Section 6.3 of SCTP-AUTH spec
 403                  */
 404                 if (first_time && (subtype.chunk == SCTP_CID_AUTH)) {
 405                         struct sctp_chunkhdr *next_hdr;
 406
 407                         next_hdr = sctp_inq_peek(inqueue);
 408                         if (!next_hdr)
 409                                 goto normal;
 410
 411                         /* If the next chunk is COOKIE-ECHO, skip the AUTH
 412                          * chunk while saving a pointer to it so we can do
 413                          * Authentication later (during cookie-echo
 414                          * processing).
 415                          */
 416                         if (next_hdr->type == SCTP_CID_COOKIE_ECHO) {
 417                                 chunk->auth_chunk = skb_clone(chunk->skb,
 418                                                                 GFP_ATOMIC);
 419                                 chunk->auth = 1;
 420                                 continue;
 421                         }
 422                 }
 423 normal:
 424                 /* We might have grown an association since last we
 425                  * looked, so try again.
 426                  *
 427                  * This happens when we've just processed our
 428                  * COOKIE-ECHO chunk.
 429                  */
 430                 if (NULL == chunk->asoc) {
 431                         asoc = sctp_endpoint_lookup_assoc(ep,
 432                                                           sctp_source(chunk),
 433                                                           &transport);
 434                         chunk->asoc = asoc;
 435                         chunk->transport = transport;
 436                 }
 437
 438                 state = asoc ? asoc->state : SCTP_STATE_CLOSED;
 439                 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
 440                         continue;
 441
 442                 /* Remember where the last DATA chunk came from so we
 443                  * know where to send the SACK.
 444                  */
 445                 if (asoc && sctp_chunk_is_data(chunk))
 446                         asoc->peer.last_data_from = chunk->transport;
 447                 else {
 448                         SCTP_INC_STATS(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS);
 449                         if (asoc)
 450                                 asoc->stats.ictrlchunks++;
 451                 }
 452
 453                 if (chunk->transport)
 454                         chunk->transport->last_time_heard = ktime_get();
 455
 456                 error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state,
 457                                    ep, asoc, chunk, GFP_ATOMIC);
 458
 459                 if (error && chunk)
 460                         chunk->pdiscard = 1;
 461
 462                 /* Check to see if the endpoint is freed in response to
 463                  * the incoming chunk. If so, get out of the while loop.
 464                  */
 465                 if (!sctp_sk(sk)->ep)
 466                         break;
 467
 468                 if (first_time)
 469                         first_time = 0;
 470         }
 471 }