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(sctp_hmac_algo_param_t) +
  77                                 sizeof(__u16) * SCTP_AUTH_NUM_HMACS, gfp);
  78                 if (!auth_hmacs)
  79                         goto nomem;
  80
  81                 auth_chunks = kzalloc(sizeof(sctp_chunks_param_t) +
  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(sctp_paramhdr_t) + 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 = htons(sizeof(sctp_paramhdr_t));
  99
 100                 /* If the Add-IP functionality is enabled, we must
 101                  * authenticate, ASCONF and ASCONF-ACK chunks
 102                  */
 103                 if (net->sctp.addip_enable) {
 104                         auth_chunks->chunks[0] = SCTP_CID_ASCONF;
 105                         auth_chunks->chunks[1] = SCTP_CID_ASCONF_ACK;
 106                         auth_chunks->param_hdr.length =
 107                                         htons(sizeof(sctp_paramhdr_t) + 2);
 108                 }
 109         }
 110
 111         /* Initialize the base structure. */
 112         /* What type of endpoint are we?  */
 113         ep->base.type = SCTP_EP_TYPE_SOCKET;
 114
 115         /* Initialize the basic object fields. */
 116         atomic_set(&ep->base.refcnt, 1);
 117         ep->base.dead = false;
 118
 119         /* Create an input queue.  */
 120         sctp_inq_init(&ep->base.inqueue);
 121
 122         /* Set its top-half handler */
 123         sctp_inq_set_th_handler(&ep->base.inqueue, sctp_endpoint_bh_rcv);
 124
 125         /* Initialize the bind addr area */
 126         sctp_bind_addr_init(&ep->base.bind_addr, 0);
 127
 128         /* Remember who we are attached to.  */
 129         ep->base.sk = sk;
 130         sock_hold(ep->base.sk);
 131
 132         /* Create the lists of associations.  */
 133         INIT_LIST_HEAD(&ep->asocs);
 134
 135         /* Use SCTP specific send buffer space queues.  */
 136         ep->sndbuf_policy = net->sctp.sndbuf_policy;
 137
 138         sk->sk_data_ready = sctp_data_ready;
 139         sk->sk_write_space = sctp_write_space;
 140         sock_set_flag(sk, SOCK_USE_WRITE_QUEUE);
 141
 142         /* Get the receive buffer policy for this endpoint */
 143         ep->rcvbuf_policy = net->sctp.rcvbuf_policy;
 144
 145         /* Initialize the secret key used with cookie. */
 146         get_random_bytes(ep->secret_key, sizeof(ep->secret_key));
 147
 148         /* SCTP-AUTH extensions*/
 149         INIT_LIST_HEAD(&ep->endpoint_shared_keys);
 150         null_key = sctp_auth_shkey_create(0, gfp);
 151         if (!null_key)
 152                 goto nomem;
 153
 154         list_add(&null_key->key_list, &ep->endpoint_shared_keys);
 155
 156         /* Allocate and initialize transorms arrays for supported HMACs. */
 157         err = sctp_auth_init_hmacs(ep, gfp);
 158         if (err)
 159                 goto nomem_hmacs;
 160
 161         /* Add the null key to the endpoint shared keys list and
 162          * set the hmcas and chunks pointers.
 163          */
 164         ep->auth_hmacs_list = auth_hmacs;
 165         ep->auth_chunk_list = auth_chunks;
 166         ep->prsctp_enable = net->sctp.prsctp_enable;
 167         ep->reconf_enable = net->sctp.reconf_enable;
 168
 169         return ep;
 170
 171 nomem_hmacs:
 172         sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
 173 nomem:
 174         /* Free all allocations */
 175         kfree(auth_hmacs);
 176         kfree(auth_chunks);
 177         kfree(ep->digest);
 178         return NULL;
 179
 180 }
 181
 182 /* Create a sctp_endpoint with all that boring stuff initialized.
 183  * Returns NULL if there isn't enough memory.
 184  */
 185 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp)
 186 {
 187         struct sctp_endpoint *ep;
 188
 189         /* Build a local endpoint. */
 190         ep = kzalloc(sizeof(*ep), gfp);
 191         if (!ep)
 192                 goto fail;
 193
 194         if (!sctp_endpoint_init(ep, sk, gfp))
 195                 goto fail_init;
 196
 197         SCTP_DBG_OBJCNT_INC(ep);
 198         return ep;
 199
 200 fail_init:
 201         kfree(ep);
 202 fail:
 203         return NULL;
 204 }
 205
 206 /* Add an association to an endpoint.  */
 207 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep,
 208                             struct sctp_association *asoc)
 209 {
 210         struct sock *sk = ep->base.sk;
 211
 212         /* If this is a temporary association, don't bother
 213          * since we'll be removing it shortly and don't
 214          * want anyone to find it anyway.
 215          */
 216         if (asoc->temp)
 217                 return;
 218
 219         /* Now just add it to our list of asocs */
 220         list_add_tail(&asoc->asocs, &ep->asocs);
 221
 222         /* Increment the backlog value for a TCP-style listening socket. */
 223         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
 224                 sk->sk_ack_backlog++;
 225 }
 226
 227 /* Free the endpoint structure.  Delay cleanup until
 228  * all users have released their reference count on this structure.
 229  */
 230 void sctp_endpoint_free(struct sctp_endpoint *ep)
 231 {
 232         ep->base.dead = true;
 233
 234         ep->base.sk->sk_state = SCTP_SS_CLOSED;
 235
 236         /* Unlink this endpoint, so we can't find it again! */
 237         sctp_unhash_endpoint(ep);
 238
 239         sctp_endpoint_put(ep);
 240 }
 241
 242 /* Final destructor for endpoint.  */
 243 static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
 244 {
 245         struct sock *sk;
 246
 247         if (unlikely(!ep->base.dead)) {
 248                 WARN(1, "Attempt to destroy undead endpoint %p!\n", ep);
 249                 return;
 250         }
 251
 252         /* Free the digest buffer */
 253         kfree(ep->digest);
 254
 255         /* SCTP-AUTH: Free up AUTH releated data such as shared keys
 256          * chunks and hmacs arrays that were allocated
 257          */
 258         sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
 259         kfree(ep->auth_hmacs_list);
 260         kfree(ep->auth_chunk_list);
 261
 262         /* AUTH - Free any allocated HMAC transform containers */
 263         sctp_auth_destroy_hmacs(ep->auth_hmacs);
 264
 265         /* Cleanup. */
 266         sctp_inq_free(&ep->base.inqueue);
 267         sctp_bind_addr_free(&ep->base.bind_addr);
 268
 269         memset(ep->secret_key, 0, sizeof(ep->secret_key));
 270
 271         /* Give up our hold on the sock. */
 272         sk = ep->base.sk;
 273         if (sk != NULL) {
 274                 /* Remove and free the port */
 275                 if (sctp_sk(sk)->bind_hash)
 276                         sctp_put_port(sk);
 277
 278                 sctp_sk(sk)->ep = NULL;
 279                 sock_put(sk);
 280         }
 281
 282         kfree(ep);
 283         SCTP_DBG_OBJCNT_DEC(ep);
 284 }
 285
 286 /* Hold a reference to an endpoint. */
 287 void sctp_endpoint_hold(struct sctp_endpoint *ep)
 288 {
 289         atomic_inc(&ep->base.refcnt);
 290 }
 291
 292 /* Release a reference to an endpoint and clean up if there are
 293  * no more references.
 294  */
 295 void sctp_endpoint_put(struct sctp_endpoint *ep)
 296 {
 297         if (atomic_dec_and_test(&ep->base.refcnt))
 298                 sctp_endpoint_destroy(ep);
 299 }
 300
 301 /* Is this the endpoint we are looking for?  */
 302 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
 303                                                struct net *net,
 304                                                const union sctp_addr *laddr)
 305 {
 306         struct sctp_endpoint *retval = NULL;
 307
 308         if ((htons(ep->base.bind_addr.port) == laddr->v4.sin_port) &&
 309             net_eq(sock_net(ep->base.sk), net)) {
 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 lookup the transport from hashtable at first, then get association
 320  * through t->assoc.
 321  */
 322 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_transport *t;
 329
 330         *transport = NULL;
 331
 332         /* If the local port is not set, there can't be any associations
 333          * on this endpoint.
 334          */
 335         if (!ep->base.bind_addr.port)
 336                 return NULL;
 337
 338         rcu_read_lock();
 339         t = sctp_epaddr_lookup_transport(ep, paddr);
 340         if (!t)
 341                 goto out;
 342
 343         *transport = t;
 344         asoc = t->asoc;
 345 out:
 346         rcu_read_unlock();
 347         return asoc;
 348 }
 349
 350 /* Look for any peeled off association from the endpoint that matches the
 351  * given peer address.
 352  */
 353 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
 354                                 const union sctp_addr *paddr)
 355 {
 356         struct sctp_sockaddr_entry *addr;
 357         struct sctp_bind_addr *bp;
 358         struct net *net = sock_net(ep->base.sk);
 359
 360         bp = &ep->base.bind_addr;
 361         /* This function is called with the socket lock held,
 362          * so the address_list can not change.
 363          */
 364         list_for_each_entry(addr, &bp->address_list, list) {
 365                 if (sctp_has_association(net, &addr->a, paddr))
 366                         return 1;
 367         }
 368
 369         return 0;
 370 }
 371
 372 /* Do delayed input processing.  This is scheduled by sctp_rcv().
 373  * This may be called on BH or task time.
 374  */
 375 static void sctp_endpoint_bh_rcv(struct work_struct *work)
 376 {
 377         struct sctp_endpoint *ep =
 378                 container_of(work, struct sctp_endpoint,
 379                              base.inqueue.immediate);
 380         struct sctp_association *asoc;
 381         struct sock *sk;
 382         struct net *net;
 383         struct sctp_transport *transport;
 384         struct sctp_chunk *chunk;
 385         struct sctp_inq *inqueue;
 386         sctp_subtype_t subtype;
 387         sctp_state_t state;
 388         int error = 0;
 389         int first_time = 1;     /* is this the first time through the loop */
 390
 391         if (ep->base.dead)
 392                 return;
 393
 394         asoc = NULL;
 395         inqueue = &ep->base.inqueue;
 396         sk = ep->base.sk;
 397         net = sock_net(sk);
 398
 399         while (NULL != (chunk = sctp_inq_pop(inqueue))) {
 400                 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
 401
 402                 /* If the first chunk in the packet is AUTH, do special
 403                  * processing specified in Section 6.3 of SCTP-AUTH spec
 404                  */
 405                 if (first_time && (subtype.chunk == SCTP_CID_AUTH)) {
 406                         struct sctp_chunkhdr *next_hdr;
 407
 408                         next_hdr = sctp_inq_peek(inqueue);
 409                         if (!next_hdr)
 410                                 goto normal;
 411
 412                         /* If the next chunk is COOKIE-ECHO, skip the AUTH
 413                          * chunk while saving a pointer to it so we can do
 414                          * Authentication later (during cookie-echo
 415                          * processing).
 416                          */
 417                         if (next_hdr->type == SCTP_CID_COOKIE_ECHO) {
 418                                 chunk->auth_chunk = skb_clone(chunk->skb,
 419                                                                 GFP_ATOMIC);
 420                                 chunk->auth = 1;
 421                                 continue;
 422                         }
 423                 }
 424 normal:
 425                 /* We might have grown an association since last we
 426                  * looked, so try again.
 427                  *
 428                  * This happens when we've just processed our
 429                  * COOKIE-ECHO chunk.
 430                  */
 431                 if (NULL == chunk->asoc) {
 432                         asoc = sctp_endpoint_lookup_assoc(ep,
 433                                                           sctp_source(chunk),
 434                                                           &transport);
 435                         chunk->asoc = asoc;
 436                         chunk->transport = transport;
 437                 }
 438
 439                 state = asoc ? asoc->state : SCTP_STATE_CLOSED;
 440                 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
 441                         continue;
 442
 443                 /* Remember where the last DATA chunk came from so we
 444                  * know where to send the SACK.
 445                  */
 446                 if (asoc && sctp_chunk_is_data(chunk))
 447                         asoc->peer.last_data_from = chunk->transport;
 448                 else {
 449                         SCTP_INC_STATS(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS);
 450                         if (asoc)
 451                                 asoc->stats.ictrlchunks++;
 452                 }
 453
 454                 if (chunk->transport)
 455                         chunk->transport->last_time_heard = ktime_get();
 456
 457                 error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state,
 458                                    ep, asoc, chunk, GFP_ATOMIC);
 459
 460                 if (error && chunk)
 461                         chunk->pdiscard = 1;
 462
 463                 /* Check to see if the endpoint is freed in response to
 464                  * the incoming chunk. If so, get out of the while loop.
 465                  */
 466                 if (!sctp_sk(sk)->ep)
 467                         break;
 468
 469                 if (first_time)
 470                         first_time = 0;
 471         }
 472 }