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
 168         return ep;
 169
 170 nomem_hmacs:
 171         sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
 172 nomem:
 173         /* Free all allocations */
 174         kfree(auth_hmacs);
 175         kfree(auth_chunks);
 176         kfree(ep->digest);
 177         return NULL;
 178
 179 }
 180
 181 /* Create a sctp_endpoint with all that boring stuff initialized.
 182  * Returns NULL if there isn't enough memory.
 183  */
 184 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp)
 185 {
 186         struct sctp_endpoint *ep;
 187
 188         /* Build a local endpoint. */
 189         ep = kzalloc(sizeof(*ep), gfp);
 190         if (!ep)
 191                 goto fail;
 192
 193         if (!sctp_endpoint_init(ep, sk, gfp))
 194                 goto fail_init;
 195
 196         SCTP_DBG_OBJCNT_INC(ep);
 197         return ep;
 198
 199 fail_init:
 200         kfree(ep);
 201 fail:
 202         return NULL;
 203 }
 204
 205 /* Add an association to an endpoint.  */
 206 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep,
 207                             struct sctp_association *asoc)
 208 {
 209         struct sock *sk = ep->base.sk;
 210
 211         /* If this is a temporary association, don't bother
 212          * since we'll be removing it shortly and don't
 213          * want anyone to find it anyway.
 214          */
 215         if (asoc->temp)
 216                 return;
 217
 218         /* Now just add it to our list of asocs */
 219         list_add_tail(&asoc->asocs, &ep->asocs);
 220
 221         /* Increment the backlog value for a TCP-style listening socket. */
 222         if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING))
 223                 sk->sk_ack_backlog++;
 224 }
 225
 226 /* Free the endpoint structure.  Delay cleanup until
 227  * all users have released their reference count on this structure.
 228  */
 229 void sctp_endpoint_free(struct sctp_endpoint *ep)
 230 {
 231         ep->base.dead = true;
 232
 233         ep->base.sk->sk_state = SCTP_SS_CLOSED;
 234
 235         /* Unlink this endpoint, so we can't find it again! */
 236         sctp_unhash_endpoint(ep);
 237
 238         sctp_endpoint_put(ep);
 239 }
 240
 241 /* Final destructor for endpoint.  */
 242 static void sctp_endpoint_destroy(struct sctp_endpoint *ep)
 243 {
 244         struct sock *sk;
 245
 246         if (unlikely(!ep->base.dead)) {
 247                 WARN(1, "Attempt to destroy undead endpoint %p!\n", ep);
 248                 return;
 249         }
 250
 251         /* Free the digest buffer */
 252         kfree(ep->digest);
 253
 254         /* SCTP-AUTH: Free up AUTH releated data such as shared keys
 255          * chunks and hmacs arrays that were allocated
 256          */
 257         sctp_auth_destroy_keys(&ep->endpoint_shared_keys);
 258         kfree(ep->auth_hmacs_list);
 259         kfree(ep->auth_chunk_list);
 260
 261         /* AUTH - Free any allocated HMAC transform containers */
 262         sctp_auth_destroy_hmacs(ep->auth_hmacs);
 263
 264         /* Cleanup. */
 265         sctp_inq_free(&ep->base.inqueue);
 266         sctp_bind_addr_free(&ep->base.bind_addr);
 267
 268         memset(ep->secret_key, 0, sizeof(ep->secret_key));
 269
 270         /* Give up our hold on the sock. */
 271         sk = ep->base.sk;
 272         if (sk != NULL) {
 273                 /* Remove and free the port */
 274                 if (sctp_sk(sk)->bind_hash)
 275                         sctp_put_port(sk);
 276
 277                 sock_put(sk);
 278         }
 279
 280         kfree(ep);
 281         SCTP_DBG_OBJCNT_DEC(ep);
 282 }
 283
 284 /* Hold a reference to an endpoint. */
 285 void sctp_endpoint_hold(struct sctp_endpoint *ep)
 286 {
 287         atomic_inc(&ep->base.refcnt);
 288 }
 289
 290 /* Release a reference to an endpoint and clean up if there are
 291  * no more references.
 292  */
 293 void sctp_endpoint_put(struct sctp_endpoint *ep)
 294 {
 295         if (atomic_dec_and_test(&ep->base.refcnt))
 296                 sctp_endpoint_destroy(ep);
 297 }
 298
 299 /* Is this the endpoint we are looking for?  */
 300 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep,
 301                                                struct net *net,
 302                                                const union sctp_addr *laddr)
 303 {
 304         struct sctp_endpoint *retval = NULL;
 305
 306         if ((htons(ep->base.bind_addr.port) == laddr->v4.sin_port) &&
 307             net_eq(sock_net(ep->base.sk), net)) {
 308                 if (sctp_bind_addr_match(&ep->base.bind_addr, laddr,
 309                                          sctp_sk(ep->base.sk)))
 310                         retval = ep;
 311         }
 312
 313         return retval;
 314 }
 315
 316 /* Find the association that goes with this chunk.
 317  * We lookup the transport from hashtable at first, then get association
 318  * through t->assoc.
 319  */
 320 struct sctp_association *sctp_endpoint_lookup_assoc(
 321         const struct sctp_endpoint *ep,
 322         const union sctp_addr *paddr,
 323         struct sctp_transport **transport)
 324 {
 325         struct sctp_association *asoc = NULL;
 326         struct sctp_transport *t;
 327
 328         *transport = NULL;
 329
 330         /* If the local port is not set, there can't be any associations
 331          * on this endpoint.
 332          */
 333         if (!ep->base.bind_addr.port)
 334                 return NULL;
 335
 336         rcu_read_lock();
 337         t = sctp_epaddr_lookup_transport(ep, paddr);
 338         if (!t)
 339                 goto out;
 340
 341         *transport = t;
 342         asoc = t->asoc;
 343 out:
 344         rcu_read_unlock();
 345         return asoc;
 346 }
 347
 348 /* Look for any peeled off association from the endpoint that matches the
 349  * given peer address.
 350  */
 351 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep,
 352                                 const union sctp_addr *paddr)
 353 {
 354         struct sctp_sockaddr_entry *addr;
 355         struct sctp_bind_addr *bp;
 356         struct net *net = sock_net(ep->base.sk);
 357
 358         bp = &ep->base.bind_addr;
 359         /* This function is called with the socket lock held,
 360          * so the address_list can not change.
 361          */
 362         list_for_each_entry(addr, &bp->address_list, list) {
 363                 if (sctp_has_association(net, &addr->a, paddr))
 364                         return 1;
 365         }
 366
 367         return 0;
 368 }
 369
 370 /* Do delayed input processing.  This is scheduled by sctp_rcv().
 371  * This may be called on BH or task time.
 372  */
 373 static void sctp_endpoint_bh_rcv(struct work_struct *work)
 374 {
 375         struct sctp_endpoint *ep =
 376                 container_of(work, struct sctp_endpoint,
 377                              base.inqueue.immediate);
 378         struct sctp_association *asoc;
 379         struct sock *sk;
 380         struct net *net;
 381         struct sctp_transport *transport;
 382         struct sctp_chunk *chunk;
 383         struct sctp_inq *inqueue;
 384         sctp_subtype_t subtype;
 385         sctp_state_t state;
 386         int error = 0;
 387         int first_time = 1;     /* is this the first time through the loop */
 388
 389         if (ep->base.dead)
 390                 return;
 391
 392         asoc = NULL;
 393         inqueue = &ep->base.inqueue;
 394         sk = ep->base.sk;
 395         net = sock_net(sk);
 396
 397         while (NULL != (chunk = sctp_inq_pop(inqueue))) {
 398                 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type);
 399
 400                 /* If the first chunk in the packet is AUTH, do special
 401                  * processing specified in Section 6.3 of SCTP-AUTH spec
 402                  */
 403                 if (first_time && (subtype.chunk == SCTP_CID_AUTH)) {
 404                         struct sctp_chunkhdr *next_hdr;
 405
 406                         next_hdr = sctp_inq_peek(inqueue);
 407                         if (!next_hdr)
 408                                 goto normal;
 409
 410                         /* If the next chunk is COOKIE-ECHO, skip the AUTH
 411                          * chunk while saving a pointer to it so we can do
 412                          * Authentication later (during cookie-echo
 413                          * processing).
 414                          */
 415                         if (next_hdr->type == SCTP_CID_COOKIE_ECHO) {
 416                                 chunk->auth_chunk = skb_clone(chunk->skb,
 417                                                                 GFP_ATOMIC);
 418                                 chunk->auth = 1;
 419                                 continue;
 420                         }
 421                 }
 422 normal:
 423                 /* We might have grown an association since last we
 424                  * looked, so try again.
 425                  *
 426                  * This happens when we've just processed our
 427                  * COOKIE-ECHO chunk.
 428                  */
 429                 if (NULL == chunk->asoc) {
 430                         asoc = sctp_endpoint_lookup_assoc(ep,
 431                                                           sctp_source(chunk),
 432                                                           &transport);
 433                         chunk->asoc = asoc;
 434                         chunk->transport = transport;
 435                 }
 436
 437                 state = asoc ? asoc->state : SCTP_STATE_CLOSED;
 438                 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth)
 439                         continue;
 440
 441                 /* Remember where the last DATA chunk came from so we
 442                  * know where to send the SACK.
 443                  */
 444                 if (asoc && sctp_chunk_is_data(chunk))
 445                         asoc->peer.last_data_from = chunk->transport;
 446                 else {
 447                         SCTP_INC_STATS(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS);
 448                         if (asoc)
 449                                 asoc->stats.ictrlchunks++;
 450                 }
 451
 452                 if (chunk->transport)
 453                         chunk->transport->last_time_heard = ktime_get();
 454
 455                 error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state,
 456                                    ep, asoc, chunk, GFP_ATOMIC);
 457
 458                 if (error && chunk)
 459                         chunk->pdiscard = 1;
 460
 461                 /* Check to see if the endpoint is freed in response to
 462                  * the incoming chunk. If so, get out of the while loop.
 463                  */
 464                 if (!sctp_sk(sk)->ep)
 465                         break;
 466
 467                 if (first_time)
 468                         first_time = 0;
 469         }
 470 }