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 = 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 suported 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
 179 nomem_hmacs:
 180         sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
 181 nomem:
 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  */
 193 struct 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
 207 fail_init:
 208         kfree(ep);
 209 fail:
 210         return NULL;
 211 }
 212
 213 /* Add an association to an endpoint.  */
 214 void 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  */
 237 void 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.  */
 250 static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
 251 {
 252         SCTP_ASSERT(ep->base.dead, "Endpoint is not dead", return);
 253
 254         /* Free up the HMAC transform. */
 255         crypto_free_hash(sctp_sk(ep->base.sk)->hmac);
 256
 257         /* Free the digest buffer */
 258         kfree(ep->digest);
 259
 260         /* SCTP-AUTH: Free up AUTH releated data such as shared keys
 261          * chunks and hmacs arrays that were allocated
 262          */
 263         sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
 264         kfree(ep->auth_hmacs_list);
 265         kfree(ep->auth_chunk_list);
 266
 267         /* AUTH - Free any allocated HMAC transform containers */
 268         sctp_auth_destroy_hmacs(ep->auth_hmacs);
 269
 270         /* Cleanup. */
 271         sctp_inq_free(&ep->base.inqueue);
 272         sctp_bind_addr_free(&ep->base.bind_addr);
 273
 274         /* Remove and free the port */
 275         if (sctp_sk(ep->base.sk)->bind_hash)
 276                 sctp_put_port(ep->base.sk);
 277
 278         /* Give up our hold on the sock. */
 279         if (ep->base.sk)
 280                 sock_put(ep->base.sk);
 281
 282         /* Finally, free up our memory. */
 283         if (ep->base.malloced) {
 284                 kfree(ep);
 285                 SCTP_DBG_OBJCNT_DEC(ep);
 286         }
 287 }
 288
 289 /* Hold a reference to an endpoint. */
 290 void sctp_endpoint_hold(struct sctp_endpoint *ep)
 291 {
 292         atomic_inc(&ep->base.refcnt);
 293 }
 294
 295 /* Release a reference to an endpoint and clean up if there are
 296  * no more references.
 297  */
 298 void sctp_endpoint_put(struct sctp_endpoint *ep)
 299 {
 300         if (atomic_dec_and_test(&ep->base.refcnt))
 301                 sctp_endpoint_destroy(ep);
 302 }
 303
 304 /* Is this the endpoint we are looking for?  */
 305 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
 306                                                struct net *net,
 307                                                const union sctp_addr *laddr)
 308 {
 309         struct sctp_endpoint *retval = NULL;
 310
 311         if ((htons(ep->base.bind_addr.port) == laddr->v4.sin_port) &&
 312             net_eq(sock_net(ep->base.sk), net)) {
 313                 if (sctp_bind_addr_match(&ep->base.bind_addr, laddr,
 314                                          sctp_sk(ep->base.sk)))
 315                         retval = ep;
 316         }
 317
 318         return retval;
 319 }
 320
 321 /* Find the association that goes with this chunk.
 322  * We do a linear search of the associations for this endpoint.
 323  * We return the matching transport address too.
 324  */
 325 static struct sctp_association *__sctp_endpoint_lookup_assoc(
 326         const struct sctp_endpoint *ep,
 327         const union sctp_addr *paddr,
 328         struct sctp_transport **transport)
 329 {
 330         struct sctp_association *asoc = NULL;
 331         struct sctp_association *tmp;
 332         struct sctp_transport *t = NULL;
 333         struct sctp_hashbucket *head;
 334         struct sctp_ep_common *epb;
 335         struct hlist_node *node;
 336         int hash;
 337         int rport;
 338
 339         *transport = NULL;
 340
 341         /* If the local port is not set, there can't be any associations
 342          * on this endpoint.
 343          */
 344         if (!ep->base.bind_addr.port)
 345                 goto out;
 346
 347         rport = ntohs(paddr->v4.sin_port);
 348
 349         hash = sctp_assoc_hashfn(sock_net(ep->base.sk), ep->base.bind_addr.port,
 350                                  rport);
 351         head = &sctp_assoc_hashtable[hash];
 352         read_lock(&head->lock);
 353         sctp_for_each_hentry(epb, node, &head->chain) {
 354                 tmp = sctp_assoc(epb);
 355                 if (tmp->ep != ep || rport != tmp->peer.port)
 356                         continue;
 357
 358                 t = sctp_assoc_lookup_paddr(tmp, paddr);
 359                 if (t) {
 360                         asoc = tmp;
 361                         *transport = t;
 362                         break;
 363                 }
 364         }
 365         read_unlock(&head->lock);
 366 out:
 367         return asoc;
 368 }
 369
 370 /* Lookup association on an endpoint based on a peer address.  BH-safe.  */
 371 struct sctp_association *sctp_endpoint_lookup_assoc(
 372         const struct sctp_endpoint *ep,
 373         const union sctp_addr *paddr,
 374         struct sctp_transport **transport)
 375 {
 376         struct sctp_association *asoc;
 377
 378         sctp_local_bh_disable();
 379         asoc = __sctp_endpoint_lookup_assoc(ep, paddr, transport);
 380         sctp_local_bh_enable();
 381
 382         return asoc;
 383 }
 384
 385 /* Look for any peeled off association from the endpoint that matches the
 386  * given peer address.
 387  */
 388 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
 389                                 const union sctp_addr *paddr)
 390 {
 391         struct sctp_sockaddr_entry *addr;
 392         struct sctp_bind_addr *bp;
 393         struct net *net = sock_net(ep->base.sk);
 394
 395         bp = &ep->base.bind_addr;
 396         /* This function is called with the socket lock held,
 397          * so the address_list can not change.
 398          */
 399         list_for_each_entry(addr, &bp->address_list, list) {
 400                 if (sctp_has_association(net, &addr->a, paddr))
 401                         return 1;
 402         }
 403
 404         return 0;
 405 }
 406
 407 /* Do delayed input processing.  This is scheduled by sctp_rcv().
 408  * This may be called on BH or task time.
 409  */
 410 static void sctp_endpoint_bh_rcv(struct work_struct *work)
 411 {
 412         struct sctp_endpoint *ep =
 413                 container_of(work, struct sctp_endpoint,
 414                              base.inqueue.immediate);
 415         struct sctp_association *asoc;
 416         struct sock *sk;
 417         struct net *net;
 418         struct sctp_transport *transport;
 419         struct sctp_chunk *chunk;
 420         struct sctp_inq *inqueue;
 421         sctp_subtype_t subtype;
 422         sctp_state_t state;
 423         int error = 0;
 424         int first_time = 1;     /* is this the first time through the loop */
 425
 426         if (ep->base.dead)
 427                 return;
 428
 429         asoc = NULL;
 430         inqueue = &ep->base.inqueue;
 431         sk = ep->base.sk;
 432         net = sock_net(sk);
 433
 434         while (NULL != (chunk = sctp_inq_pop(inqueue))) {
 435                 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
 436
 437                 /* If the first chunk in the packet is AUTH, do special
 438                  * processing specified in Section 6.3 of SCTP-AUTH spec
 439                  */
 440                 if (first_time && (subtype.chunk == SCTP_CID_AUTH)) {
 441                         struct sctp_chunkhdr *next_hdr;
 442
 443                         next_hdr = sctp_inq_peek(inqueue);
 444                         if (!next_hdr)
 445                                 goto normal;
 446
 447                         /* If the next chunk is COOKIE-ECHO, skip the AUTH
 448                          * chunk while saving a pointer to it so we can do
 449                          * Authentication later (during cookie-echo
 450                          * processing).
 451                          */
 452                         if (next_hdr->type == SCTP_CID_COOKIE_ECHO) {
 453                                 chunk->auth_chunk = skb_clone(chunk->skb,
 454                                                                 GFP_ATOMIC);
 455                                 chunk->auth = 1;
 456                                 continue;
 457                         }
 458                 }
 459 normal:
 460                 /* We might have grown an association since last we
 461                  * looked, so try again.
 462                  *
 463                  * This happens when we've just processed our
 464                  * COOKIE-ECHO chunk.
 465                  */
 466                 if (NULL == chunk->asoc) {
 467                         asoc = sctp_endpoint_lookup_assoc(ep,
 468                                                           sctp_source(chunk),
 469                                                           &transport);
 470                         chunk->asoc = asoc;
 471                         chunk->transport = transport;
 472                 }
 473
 474                 state = asoc ? asoc->state : SCTP_STATE_CLOSED;
 475                 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
 476                         continue;
 477
 478                 /* Remember where the last DATA chunk came from so we
 479                  * know where to send the SACK.
 480                  */
 481                 if (asoc && sctp_chunk_is_data(chunk))
 482                         asoc->peer.last_data_from = chunk->transport;
 483                 else
 484                         SCTP_INC_STATS(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS);
 485
 486                 if (chunk->transport)
 487                         chunk->transport->last_time_heard = jiffies;
 488
 489                 error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state,
 490                                    ep, asoc, chunk, GFP_ATOMIC);
 491
 492                 if (error && chunk)
 493                         chunk->pdiscard = 1;
 494
 495                 /* Check to see if the endpoint is freed in response to
 496                  * the incoming chunk. If so, get out of the while loop.
 497                  */
 498                 if (!sctp_sk(sk)->ep)
 499                         break;
 500
 501                 if (first_time)
 502                         first_time = 0;
 503         }
 504 }