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 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
 178nomem_hmacs:
 179        sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
 180nomem:
 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 */
 192struct 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
 206fail_init:
 207        kfree(ep);
 208fail:
 209        return NULL;
 210}
 211
 212/* Add an association to an endpoint.  */
 213void 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 */
 236void 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.  */
 249static 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. */
 289void 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 */
 297void 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?  */
 304struct 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 */
 322static 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);
 362out:
 363        return asoc;
 364}
 365
 366/* Lookup association on an endpoint based on a peer address.  BH-safe.  */
 367struct 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 */
 384int 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 */
 405static 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 loop */
 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                }
 452normal:
 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}
 498
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