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, 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. */
  59static void sctp_endpoint_bh_rcv(struct work_struct *work);
  60
  61/*
  62 * Initialize the base fields of the endpoint structure.
  63 */
  64static 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 = 0;
 125        ep->base.malloced = 1;
 126
 127        /* Create an input queue.  */
 128        sctp_inq_init(&ep->base.inqueue);
 129
 130        /* Set its top-half handler */
 131        sctp_inq_set_th_handler(&ep->base.inqueue, sctp_endpoint_bh_rcv);
 132
 133        /* Initialize the bind addr area */
 134        sctp_bind_addr_init(&ep->base.bind_addr, 0);
 135
 136        /* Remember who we are attached to.  */
 137        ep->base.sk = sk;
 138        sock_hold(ep->base.sk);
 139
 140        /* Create the lists of associations.  */
 141        INIT_LIST_HEAD(&ep->asocs);
 142
 143        /* Use SCTP specific send buffer space queues.  */
 144        ep->sndbuf_policy = net->sctp.sndbuf_policy;
 145
 146        sk->sk_data_ready = sctp_data_ready;
 147        sk->sk_write_space = sctp_write_space;
 148        sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
 149
 150        /* Get the receive buffer policy for this endpoint */
 151        ep->rcvbuf_policy = net->sctp.rcvbuf_policy;
 152
 153        /* Initialize the secret key used with cookie. */
 154        get_random_bytes(&ep->secret_key[0], SCTP_SECRET_SIZE);
 155        ep->last_key = ep->current_key = 0;
 156        ep->key_changed_at = jiffies;
 157
 158        /* SCTP-AUTH extensions*/
 159        INIT_LIST_HEAD(&ep->endpoint_shared_keys);
 160        null_key = sctp_auth_shkey_create(0, GFP_KERNEL);
 161        if (!null_key)
 162                goto nomem;
 163
 164        list_add(&null_key->key_list, &ep->endpoint_shared_keys);
 165
 166        /* Allocate and initialize transorms arrays for supported HMACs. */
 167        err = sctp_auth_init_hmacs(ep, gfp);
 168        if (err)
 169                goto nomem_hmacs;
 170
 171        /* Add the null key to the endpoint shared keys list and
 172         * set the hmcas and chunks pointers.
 173         */
 174        ep->auth_hmacs_list = auth_hmacs;
 175        ep->auth_chunk_list = auth_chunks;
 176
 177        return ep;
 178
 179nomem_hmacs:
 180        sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
 181nomem:
 182        /* Free all allocations */
 183        kfree(auth_hmacs);
 184        kfree(auth_chunks);
 185        kfree(ep->digest);
 186        return NULL;
 187
 188}
 189
 190/* Create a sctp_endpoint with all that boring stuff initialized.
 191 * Returns NULL if there isn't enough memory.
 192 */
 193struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp)
 194{
 195        struct sctp_endpoint *ep;
 196
 197        /* Build a local endpoint. */
 198        ep = t_new(struct sctp_endpoint, gfp);
 199        if (!ep)
 200                goto fail;
 201        if (!sctp_endpoint_init(ep, sk, gfp))
 202                goto fail_init;
 203        ep->base.malloced = 1;
 204        SCTP_DBG_OBJCNT_INC(ep);
 205        return ep;
 206
 207fail_init:
 208        kfree(ep);
 209fail:
 210        return NULL;
 211}
 212
 213/* Add an association to an endpoint.  */
 214void sctp_endpoint_add_asoc(struct sctp_endpoint *ep,
 215                            struct sctp_association *asoc)
 216{
 217        struct sock *sk = ep->base.sk;
 218
 219        /* If this is a temporary association, don't bother
 220         * since we'll be removing it shortly and don't
 221         * want anyone to find it anyway.
 222         */
 223        if (asoc->temp)
 224                return;
 225
 226        /* Now just add it to our list of asocs */
 227        list_add_tail(&asoc->asocs, &ep->asocs);
 228
 229        /* Increment the backlog value for a TCP-style listening socket. */
 230        if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
 231                sk->sk_ack_backlog++;
 232}
 233
 234/* Free the endpoint structure.  Delay cleanup until
 235 * all users have released their reference count on this structure.
 236 */
 237void sctp_endpoint_free(struct sctp_endpoint *ep)
 238{
 239        ep->base.dead = 1;
 240
 241        ep->base.sk->sk_state = SCTP_SS_CLOSED;
 242
 243        /* Unlink this endpoint, so we can't find it again! */
 244        sctp_unhash_endpoint(ep);
 245
 246        sctp_endpoint_put(ep);
 247}
 248
 249/* Final destructor for endpoint.  */
 250static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
 251{
 252        int i;
 253
 254        SCTP_ASSERT(ep->base.dead, "Endpoint is not dead", return);
 255
 256        /* Free up the HMAC transform. */
 257        crypto_free_hash(sctp_sk(ep->base.sk)->hmac);
 258
 259        /* Free the digest buffer */
 260        kfree(ep->digest);
 261
 262        /* SCTP-AUTH: Free up AUTH releated data such as shared keys
 263         * chunks and hmacs arrays that were allocated
 264         */
 265        sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
 266        kfree(ep->auth_hmacs_list);
 267        kfree(ep->auth_chunk_list);
 268
 269        /* AUTH - Free any allocated HMAC transform containers */
 270        sctp_auth_destroy_hmacs(ep->auth_hmacs);
 271
 272        /* Cleanup. */
 273        sctp_inq_free(&ep->base.inqueue);
 274        sctp_bind_addr_free(&ep->base.bind_addr);
 275
 276        for (i = 0; i < SCTP_HOW_MANY_SECRETS; ++i)
 277                memset(&ep->secret_key[i], 0, SCTP_SECRET_SIZE);
 278
 279        /* Remove and free the port */
 280        if (sctp_sk(ep->base.sk)->bind_hash)
 281                sctp_put_port(ep->base.sk);
 282
 283        /* Give up our hold on the sock. */
 284        if (ep->base.sk)
 285                sock_put(ep->base.sk);
 286
 287        /* Finally, free up our memory. */
 288        if (ep->base.malloced) {
 289                kfree(ep);
 290                SCTP_DBG_OBJCNT_DEC(ep);
 291        }
 292}
 293
 294/* Hold a reference to an endpoint. */
 295void sctp_endpoint_hold(struct sctp_endpoint *ep)
 296{
 297        atomic_inc(&ep->base.refcnt);
 298}
 299
 300/* Release a reference to an endpoint and clean up if there are
 301 * no more references.
 302 */
 303void sctp_endpoint_put(struct sctp_endpoint *ep)
 304{
 305        if (atomic_dec_and_test(&ep->base.refcnt))
 306                sctp_endpoint_destroy(ep);
 307}
 308
 309/* Is this the endpoint we are looking for?  */
 310struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
 311                                               struct net *net,
 312                                               const union sctp_addr *laddr)
 313{
 314        struct sctp_endpoint *retval = NULL;
 315
 316        if ((htons(ep->base.bind_addr.port) == laddr->v4.sin_port) &&
 317            net_eq(sock_net(ep->base.sk), net)) {
 318                if (sctp_bind_addr_match(&ep->base.bind_addr, laddr,
 319                                         sctp_sk(ep->base.sk)))
 320                        retval = ep;
 321        }
 322
 323        return retval;
 324}
 325
 326/* Find the association that goes with this chunk.
 327 * We do a linear search of the associations for this endpoint.
 328 * We return the matching transport address too.
 329 */
 330static struct sctp_association *__sctp_endpoint_lookup_assoc(
 331        const struct sctp_endpoint *ep,
 332        const union sctp_addr *paddr,
 333        struct sctp_transport **transport)
 334{
 335        struct sctp_association *asoc = NULL;
 336        struct sctp_association *tmp;
 337        struct sctp_transport *t = NULL;
 338        struct sctp_hashbucket *head;
 339        struct sctp_ep_common *epb;
 340        struct hlist_node *node;
 341        int hash;
 342        int rport;
 343
 344        *transport = NULL;
 345
 346        /* If the local port is not set, there can't be any associations
 347         * on this endpoint.
 348         */
 349        if (!ep->base.bind_addr.port)
 350                goto out;
 351
 352        rport = ntohs(paddr->v4.sin_port);
 353
 354        hash = sctp_assoc_hashfn(sock_net(ep->base.sk), ep->base.bind_addr.port,
 355                                 rport);
 356        head = &sctp_assoc_hashtable[hash];
 357        read_lock(&head->lock);
 358        sctp_for_each_hentry(epb, node, &head->chain) {
 359                tmp = sctp_assoc(epb);
 360                if (tmp->ep != ep || rport != tmp->peer.port)
 361                        continue;
 362
 363                t = sctp_assoc_lookup_paddr(tmp, paddr);
 364                if (t) {
 365                        asoc = tmp;
 366                        *transport = t;
 367                        break;
 368                }
 369        }
 370        read_unlock(&head->lock);
 371out:
 372        return asoc;
 373}
 374
 375/* Lookup association on an endpoint based on a peer address.  BH-safe.  */
 376struct sctp_association *sctp_endpoint_lookup_assoc(
 377        const struct sctp_endpoint *ep,
 378        const union sctp_addr *paddr,
 379        struct sctp_transport **transport)
 380{
 381        struct sctp_association *asoc;
 382
 383        sctp_local_bh_disable();
 384        asoc = __sctp_endpoint_lookup_assoc(ep, paddr, transport);
 385        sctp_local_bh_enable();
 386
 387        return asoc;
 388}
 389
 390/* Look for any peeled off association from the endpoint that matches the
 391 * given peer address.
 392 */
 393int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
 394                                const union sctp_addr *paddr)
 395{
 396        struct sctp_sockaddr_entry *addr;
 397        struct sctp_bind_addr *bp;
 398        struct net *net = sock_net(ep->base.sk);
 399
 400        bp = &ep->base.bind_addr;
 401        /* This function is called with the socket lock held,
 402         * so the address_list can not change.
 403         */
 404        list_for_each_entry(addr, &bp->address_list, list) {
 405                if (sctp_has_association(net, &addr->a, paddr))
 406                        return 1;
 407        }
 408
 409        return 0;
 410}
 411
 412/* Do delayed input processing.  This is scheduled by sctp_rcv().
 413 * This may be called on BH or task time.
 414 */
 415static void sctp_endpoint_bh_rcv(struct work_struct *work)
 416{
 417        struct sctp_endpoint *ep =
 418                container_of(work, struct sctp_endpoint,
 419                             base.inqueue.immediate);
 420        struct sctp_association *asoc;
 421        struct sock *sk;
 422        struct net *net;
 423        struct sctp_transport *transport;
 424        struct sctp_chunk *chunk;
 425        struct sctp_inq *inqueue;
 426        sctp_subtype_t subtype;
 427        sctp_state_t state;
 428        int error = 0;
 429        int first_time = 1;     /* is this the first time through the loop */
 430
 431        if (ep->base.dead)
 432                return;
 433
 434        asoc = NULL;
 435        inqueue = &ep->base.inqueue;
 436        sk = ep->base.sk;
 437        net = sock_net(sk);
 438
 439        while (NULL != (chunk = sctp_inq_pop(inqueue))) {
 440                subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
 441
 442                /* If the first chunk in the packet is AUTH, do special
 443                 * processing specified in Section 6.3 of SCTP-AUTH spec
 444                 */
 445                if (first_time && (subtype.chunk == SCTP_CID_AUTH)) {
 446                        struct sctp_chunkhdr *next_hdr;
 447
 448                        next_hdr = sctp_inq_peek(inqueue);
 449                        if (!next_hdr)
 450                                goto normal;
 451
 452                        /* If the next chunk is COOKIE-ECHO, skip the AUTH
 453                         * chunk while saving a pointer to it so we can do
 454                         * Authentication later (during cookie-echo
 455                         * processing).
 456                         */
 457                        if (next_hdr->type == SCTP_CID_COOKIE_ECHO) {
 458                                chunk->auth_chunk = skb_clone(chunk->skb,
 459                                                                GFP_ATOMIC);
 460                                chunk->auth = 1;
 461                                continue;
 462                        }
 463                }
 464normal:
 465                /* We might have grown an association since last we
 466                 * looked, so try again.
 467                 *
 468                 * This happens when we've just processed our
 469                 * COOKIE-ECHO chunk.
 470                 */
 471                if (NULL == chunk->asoc) {
 472                        asoc = sctp_endpoint_lookup_assoc(ep,
 473                                                          sctp_source(chunk),
 474                                                          &transport);
 475                        chunk->asoc = asoc;
 476                        chunk->transport = transport;
 477                }
 478
 479                state = asoc ? asoc->state : SCTP_STATE_CLOSED;
 480                if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
 481                        continue;
 482
 483                /* Remember where the last DATA chunk came from so we
 484                 * know where to send the SACK.
 485                 */
 486                if (asoc && sctp_chunk_is_data(chunk))
 487                        asoc->peer.last_data_from = chunk->transport;
 488                else {
 489                        SCTP_INC_STATS(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS);
 490                        if (asoc)
 491                                asoc->stats.ictrlchunks++;
 492                }
 493
 494                if (chunk->transport)
 495                        chunk->transport->last_time_heard = jiffies;
 496
 497                error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state,
 498                                   ep, asoc, chunk, GFP_ATOMIC);
 499
 500                if (error && chunk)
 501                        chunk->pdiscard = 1;
 502
 503                /* Check to see if the endpoint is freed in response to
 504                 * the incoming chunk. If so, get out of the while loop.
 505                 */
 506                if (!sctp_sk(sk)->ep)
 507                        break;
 508
 509                if (first_time)
 510                        first_time = 0;
 511        }
 512}
 513
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