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(struct_size(auth_hmacs, hmac_ids, 77 SCTP_AUTH_NUM_HMACS), gfp); 78 if (!auth_hmacs) 79 goto nomem; 80 81 auth_chunks = kzalloc(sizeof(*auth_chunks) + 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(struct sctp_paramhdr) + 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 = 99 htons(sizeof(struct sctp_paramhdr)); 100 101 /* If the Add-IP functionality is enabled, we must 102 * authenticate, ASCONF and ASCONF-ACK chunks 103 */ 104 if (net->sctp.addip_enable) { 105 auth_chunks->chunks[0] = SCTP_CID_ASCONF; 106 auth_chunks->chunks[1] = SCTP_CID_ASCONF_ACK; 107 auth_chunks->param_hdr.length = 108 htons(sizeof(struct sctp_paramhdr) + 2); 109 } 110 111 /* Allocate and initialize transorms arrays for supported 112 * HMACs. 113 */ 114 err = sctp_auth_init_hmacs(ep, gfp); 115 if (err) 116 goto nomem; 117 } 118 119 /* Initialize the base structure. */ 120 /* What type of endpoint are we? */ 121 ep->base.type = SCTP_EP_TYPE_SOCKET; 122 123 /* Initialize the basic object fields. */ 124 refcount_set(&ep->base.refcnt, 1); 125 ep->base.dead = false; 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, sizeof(ep->secret_key)); 155 156 /* SCTP-AUTH extensions*/ 157 INIT_LIST_HEAD(&ep->endpoint_shared_keys); 158 null_key = sctp_auth_shkey_create(0, gfp); 159 if (!null_key) 160 goto nomem_shkey; 161 162 list_add(&null_key->key_list, &ep->endpoint_shared_keys); 163 164 /* Add the null key to the endpoint shared keys list and 165 * set the hmcas and chunks pointers. 166 */ 167 ep->auth_hmacs_list = auth_hmacs; 168 ep->auth_chunk_list = auth_chunks; 169 ep->prsctp_enable = net->sctp.prsctp_enable; 170 ep->reconf_enable = net->sctp.reconf_enable; 171 172 return ep; 173 174 nomem_shkey: 175 sctp_auth_destroy_hmacs(ep->auth_hmacs); 176 nomem: 177 /* Free all allocations */ 178 kfree(auth_hmacs); 179 kfree(auth_chunks); 180 kfree(ep->digest); 181 return NULL; 182 183 } 184 185 /* Create a sctp_endpoint with all that boring stuff initialized. 186 * Returns NULL if there isn't enough memory. 187 */ 188 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp) 189 { 190 struct sctp_endpoint *ep; 191 192 /* Build a local endpoint. */ 193 ep = kzalloc(sizeof(*ep), gfp); 194 if (!ep) 195 goto fail; 196 197 if (!sctp_endpoint_init(ep, sk, gfp)) 198 goto fail_init; 199 200 SCTP_DBG_OBJCNT_INC(ep); 201 return ep; 202 203 fail_init: 204 kfree(ep); 205 fail: 206 return NULL; 207 } 208 209 /* Add an association to an endpoint. */ 210 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep, 211 struct sctp_association *asoc) 212 { 213 struct sock *sk = ep->base.sk; 214 215 /* If this is a temporary association, don't bother 216 * since we'll be removing it shortly and don't 217 * want anyone to find it anyway. 218 */ 219 if (asoc->temp) 220 return; 221 222 /* Now just add it to our list of asocs */ 223 list_add_tail(&asoc->asocs, &ep->asocs); 224 225 /* Increment the backlog value for a TCP-style listening socket. */ 226 if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING)) 227 sk->sk_ack_backlog++; 228 } 229 230 /* Free the endpoint structure. Delay cleanup until 231 * all users have released their reference count on this structure. 232 */ 233 void sctp_endpoint_free(struct sctp_endpoint *ep) 234 { 235 ep->base.dead = true; 236 237 inet_sk_set_state(ep->base.sk, SCTP_SS_CLOSED); 238 239 /* Unlink this endpoint, so we can't find it again! */ 240 sctp_unhash_endpoint(ep); 241 242 sctp_endpoint_put(ep); 243 } 244 245 /* Final destructor for endpoint. */ 246 static void sctp_endpoint_destroy(struct sctp_endpoint *ep) 247 { 248 struct sock *sk; 249 250 if (unlikely(!ep->base.dead)) { 251 WARN(1, "Attempt to destroy undead endpoint %p!\n", ep); 252 return; 253 } 254 255 /* Free the digest buffer */ 256 kfree(ep->digest); 257 258 /* SCTP-AUTH: Free up AUTH releated data such as shared keys 259 * chunks and hmacs arrays that were allocated 260 */ 261 sctp_auth_destroy_keys(&ep->endpoint_shared_keys); 262 kfree(ep->auth_hmacs_list); 263 kfree(ep->auth_chunk_list); 264 265 /* AUTH - Free any allocated HMAC transform containers */ 266 sctp_auth_destroy_hmacs(ep->auth_hmacs); 267 268 /* Cleanup. */ 269 sctp_inq_free(&ep->base.inqueue); 270 sctp_bind_addr_free(&ep->base.bind_addr); 271 272 memset(ep->secret_key, 0, sizeof(ep->secret_key)); 273 274 sk = ep->base.sk; 275 /* Remove and free the port */ 276 if (sctp_sk(sk)->bind_hash) 277 sctp_put_port(sk); 278 279 sctp_sk(sk)->ep = NULL; 280 /* Give up our hold on the sock */ 281 sock_put(sk); 282 283 kfree(ep); 284 SCTP_DBG_OBJCNT_DEC(ep); 285 } 286 287 /* Hold a reference to an endpoint. */ 288 void sctp_endpoint_hold(struct sctp_endpoint *ep) 289 { 290 refcount_inc(&ep->base.refcnt); 291 } 292 293 /* Release a reference to an endpoint and clean up if there are 294 * no more references. 295 */ 296 void sctp_endpoint_put(struct sctp_endpoint *ep) 297 { 298 if (refcount_dec_and_test(&ep->base.refcnt)) 299 sctp_endpoint_destroy(ep); 300 } 301 302 /* Is this the endpoint we are looking for? */ 303 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep, 304 struct net *net, 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 net_eq(sock_net(ep->base.sk), net)) { 311 if (sctp_bind_addr_match(&ep->base.bind_addr, laddr, 312 sctp_sk(ep->base.sk))) 313 retval = ep; 314 } 315 316 return retval; 317 } 318 319 /* Find the association that goes with this chunk. 320 * We lookup the transport from hashtable at first, then get association 321 * through t->assoc. 322 */ 323 struct sctp_association *sctp_endpoint_lookup_assoc( 324 const struct sctp_endpoint *ep, 325 const union sctp_addr *paddr, 326 struct sctp_transport **transport) 327 { 328 struct sctp_association *asoc = NULL; 329 struct sctp_transport *t; 330 331 *transport = NULL; 332 333 /* If the local port is not set, there can't be any associations 334 * on this endpoint. 335 */ 336 if (!ep->base.bind_addr.port) 337 return NULL; 338 339 rcu_read_lock(); 340 t = sctp_epaddr_lookup_transport(ep, paddr); 341 if (!t) 342 goto out; 343 344 *transport = t; 345 asoc = t->asoc; 346 out: 347 rcu_read_unlock(); 348 return asoc; 349 } 350 351 /* Look for any peeled off association from the endpoint that matches the 352 * given peer address. 353 */ 354 bool sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep, 355 const union sctp_addr *paddr) 356 { 357 struct sctp_sockaddr_entry *addr; 358 struct sctp_bind_addr *bp; 359 struct net *net = sock_net(ep->base.sk); 360 361 bp = &ep->base.bind_addr; 362 /* This function is called with the socket lock held, 363 * so the address_list can not change. 364 */ 365 list_for_each_entry(addr, &bp->address_list, list) { 366 if (sctp_has_association(net, &addr->a, paddr)) 367 return true; 368 } 369 370 return false; 371 } 372 373 /* Do delayed input processing. This is scheduled by sctp_rcv(). 374 * This may be called on BH or task time. 375 */ 376 static void sctp_endpoint_bh_rcv(struct work_struct *work) 377 { 378 struct sctp_endpoint *ep = 379 container_of(work, struct sctp_endpoint, 380 base.inqueue.immediate); 381 struct sctp_association *asoc; 382 struct sock *sk; 383 struct net *net; 384 struct sctp_transport *transport; 385 struct sctp_chunk *chunk; 386 struct sctp_inq *inqueue; 387 union sctp_subtype subtype; 388 enum sctp_state state; 389 int error = 0; 390 int first_time = 1; /* is this the first time through the loop */ 391 392 if (ep->base.dead) 393 return; 394 395 asoc = NULL; 396 inqueue = &ep->base.inqueue; 397 sk = ep->base.sk; 398 net = sock_net(sk); 399 400 while (NULL != (chunk = sctp_inq_pop(inqueue))) { 401 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type); 402 403 /* If the first chunk in the packet is AUTH, do special 404 * processing specified in Section 6.3 of SCTP-AUTH spec 405 */ 406 if (first_time && (subtype.chunk == SCTP_CID_AUTH)) { 407 struct sctp_chunkhdr *next_hdr; 408 409 next_hdr = sctp_inq_peek(inqueue); 410 if (!next_hdr) 411 goto normal; 412 413 /* If the next chunk is COOKIE-ECHO, skip the AUTH 414 * chunk while saving a pointer to it so we can do 415 * Authentication later (during cookie-echo 416 * processing). 417 */ 418 if (next_hdr->type == SCTP_CID_COOKIE_ECHO) { 419 chunk->auth_chunk = skb_clone(chunk->skb, 420 GFP_ATOMIC); 421 chunk->auth = 1; 422 continue; 423 } 424 } 425 normal: 426 /* We might have grown an association since last we 427 * looked, so try again. 428 * 429 * This happens when we've just processed our 430 * COOKIE-ECHO chunk. 431 */ 432 if (NULL == chunk->asoc) { 433 asoc = sctp_endpoint_lookup_assoc(ep, 434 sctp_source(chunk), 435 &transport); 436 chunk->asoc = asoc; 437 chunk->transport = transport; 438 } 439 440 state = asoc ? asoc->state : SCTP_STATE_CLOSED; 441 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth) 442 continue; 443 444 /* Remember where the last DATA chunk came from so we 445 * know where to send the SACK. 446 */ 447 if (asoc && sctp_chunk_is_data(chunk)) 448 asoc->peer.last_data_from = chunk->transport; 449 else { 450 SCTP_INC_STATS(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS); 451 if (asoc) 452 asoc->stats.ictrlchunks++; 453 } 454 455 if (chunk->transport) 456 chunk->transport->last_time_heard = ktime_get(); 457 458 error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state, 459 ep, asoc, chunk, GFP_ATOMIC); 460 461 if (error && chunk) 462 chunk->pdiscard = 1; 463 464 /* Check to see if the endpoint is freed in response to 465 * the incoming chunk. If so, get out of the while loop. 466 */ 467 if (!sctp_sk(sk)->ep) 468 break; 469 470 if (first_time) 471 first_time = 0; 472 } 473 } 474