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(*auth_hmacs) + 77 sizeof(__u16) * 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 } 111 112 /* Initialize the base structure. */ 113 /* What type of endpoint are we? */ 114 ep->base.type = SCTP_EP_TYPE_SOCKET; 115 116 /* Initialize the basic object fields. */ 117 refcount_set(&ep->base.refcnt, 1); 118 ep->base.dead = false; 119 120 /* Create an input queue. */ 121 sctp_inq_init(&ep->base.inqueue); 122 123 /* Set its top-half handler */ 124 sctp_inq_set_th_handler(&ep->base.inqueue, sctp_endpoint_bh_rcv); 125 126 /* Initialize the bind addr area */ 127 sctp_bind_addr_init(&ep->base.bind_addr, 0); 128 129 /* Remember who we are attached to. */ 130 ep->base.sk = sk; 131 sock_hold(ep->base.sk); 132 133 /* Create the lists of associations. */ 134 INIT_LIST_HEAD(&ep->asocs); 135 136 /* Use SCTP specific send buffer space queues. */ 137 ep->sndbuf_policy = net->sctp.sndbuf_policy; 138 139 sk->sk_data_ready = sctp_data_ready; 140 sk->sk_write_space = sctp_write_space; 141 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE); 142 143 /* Get the receive buffer policy for this endpoint */ 144 ep->rcvbuf_policy = net->sctp.rcvbuf_policy; 145 146 /* Initialize the secret key used with cookie. */ 147 get_random_bytes(ep->secret_key, sizeof(ep->secret_key)); 148 149 /* SCTP-AUTH extensions*/ 150 INIT_LIST_HEAD(&ep->endpoint_shared_keys); 151 null_key = sctp_auth_shkey_create(0, gfp); 152 if (!null_key) 153 goto nomem; 154 155 list_add(&null_key->key_list, &ep->endpoint_shared_keys); 156 157 /* Allocate and initialize transorms arrays for supported HMACs. */ 158 err = sctp_auth_init_hmacs(ep, gfp); 159 if (err) 160 goto nomem_hmacs; 161 162 /* Add the null key to the endpoint shared keys list and 163 * set the hmcas and chunks pointers. 164 */ 165 ep->auth_hmacs_list = auth_hmacs; 166 ep->auth_chunk_list = auth_chunks; 167 ep->prsctp_enable = net->sctp.prsctp_enable; 168 ep->reconf_enable = net->sctp.reconf_enable; 169 170 return ep; 171 172 nomem_hmacs: 173 sctp_auth_destroy_keys(&ep->endpoint_shared_keys); 174 nomem: 175 /* Free all allocations */ 176 kfree(auth_hmacs); 177 kfree(auth_chunks); 178 kfree(ep->digest); 179 return NULL; 180 181 } 182 183 /* Create a sctp_endpoint with all that boring stuff initialized. 184 * Returns NULL if there isn't enough memory. 185 */ 186 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp) 187 { 188 struct sctp_endpoint *ep; 189 190 /* Build a local endpoint. */ 191 ep = kzalloc(sizeof(*ep), gfp); 192 if (!ep) 193 goto fail; 194 195 if (!sctp_endpoint_init(ep, sk, gfp)) 196 goto fail_init; 197 198 SCTP_DBG_OBJCNT_INC(ep); 199 return ep; 200 201 fail_init: 202 kfree(ep); 203 fail: 204 return NULL; 205 } 206 207 /* Add an association to an endpoint. */ 208 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep, 209 struct sctp_association *asoc) 210 { 211 struct sock *sk = ep->base.sk; 212 213 /* If this is a temporary association, don't bother 214 * since we'll be removing it shortly and don't 215 * want anyone to find it anyway. 216 */ 217 if (asoc->temp) 218 return; 219 220 /* Now just add it to our list of asocs */ 221 list_add_tail(&asoc->asocs, &ep->asocs); 222 223 /* Increment the backlog value for a TCP-style listening socket. */ 224 if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING)) 225 sk->sk_ack_backlog++; 226 } 227 228 /* Free the endpoint structure. Delay cleanup until 229 * all users have released their reference count on this structure. 230 */ 231 void sctp_endpoint_free(struct sctp_endpoint *ep) 232 { 233 ep->base.dead = true; 234 235 ep->base.sk->sk_state = SCTP_SS_CLOSED; 236 237 /* Unlink this endpoint, so we can't find it again! */ 238 sctp_unhash_endpoint(ep); 239 240 sctp_endpoint_put(ep); 241 } 242 243 /* Final destructor for endpoint. */ 244 static void sctp_endpoint_destroy(struct sctp_endpoint *ep) 245 { 246 struct sock *sk; 247 248 if (unlikely(!ep->base.dead)) { 249 WARN(1, "Attempt to destroy undead endpoint %p!\n", ep); 250 return; 251 } 252 253 /* Free the digest buffer */ 254 kfree(ep->digest); 255 256 /* SCTP-AUTH: Free up AUTH releated data such as shared keys 257 * chunks and hmacs arrays that were allocated 258 */ 259 sctp_auth_destroy_keys(&ep->endpoint_shared_keys); 260 kfree(ep->auth_hmacs_list); 261 kfree(ep->auth_chunk_list); 262 263 /* AUTH - Free any allocated HMAC transform containers */ 264 sctp_auth_destroy_hmacs(ep->auth_hmacs); 265 266 /* Cleanup. */ 267 sctp_inq_free(&ep->base.inqueue); 268 sctp_bind_addr_free(&ep->base.bind_addr); 269 270 memset(ep->secret_key, 0, sizeof(ep->secret_key)); 271 272 sk = ep->base.sk; 273 /* Remove and free the port */ 274 if (sctp_sk(sk)->bind_hash) 275 sctp_put_port(sk); 276 277 sctp_sk(sk)->ep = NULL; 278 /* Give up our hold on the sock */ 279 sock_put(sk); 280 281 kfree(ep); 282 SCTP_DBG_OBJCNT_DEC(ep); 283 } 284 285 /* Hold a reference to an endpoint. */ 286 void sctp_endpoint_hold(struct sctp_endpoint *ep) 287 { 288 refcount_inc(&ep->base.refcnt); 289 } 290 291 /* Release a reference to an endpoint and clean up if there are 292 * no more references. 293 */ 294 void sctp_endpoint_put(struct sctp_endpoint *ep) 295 { 296 if (refcount_dec_and_test(&ep->base.refcnt)) 297 sctp_endpoint_destroy(ep); 298 } 299 300 /* Is this the endpoint we are looking for? */ 301 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep, 302 struct net *net, 303 const union sctp_addr *laddr) 304 { 305 struct sctp_endpoint *retval = NULL; 306 307 if ((htons(ep->base.bind_addr.port) == laddr->v4.sin_port) && 308 net_eq(sock_net(ep->base.sk), net)) { 309 if (sctp_bind_addr_match(&ep->base.bind_addr, laddr, 310 sctp_sk(ep->base.sk))) 311 retval = ep; 312 } 313 314 return retval; 315 } 316 317 /* Find the association that goes with this chunk. 318 * We lookup the transport from hashtable at first, then get association 319 * through t->assoc. 320 */ 321 struct sctp_association *sctp_endpoint_lookup_assoc( 322 const struct sctp_endpoint *ep, 323 const union sctp_addr *paddr, 324 struct sctp_transport **transport) 325 { 326 struct sctp_association *asoc = NULL; 327 struct sctp_transport *t; 328 329 *transport = NULL; 330 331 /* If the local port is not set, there can't be any associations 332 * on this endpoint. 333 */ 334 if (!ep->base.bind_addr.port) 335 return NULL; 336 337 rcu_read_lock(); 338 t = sctp_epaddr_lookup_transport(ep, paddr); 339 if (!t) 340 goto out; 341 342 *transport = t; 343 asoc = t->asoc; 344 out: 345 rcu_read_unlock(); 346 return asoc; 347 } 348 349 /* Look for any peeled off association from the endpoint that matches the 350 * given peer address. 351 */ 352 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep, 353 const union sctp_addr *paddr) 354 { 355 struct sctp_sockaddr_entry *addr; 356 struct sctp_bind_addr *bp; 357 struct net *net = sock_net(ep->base.sk); 358 359 bp = &ep->base.bind_addr; 360 /* This function is called with the socket lock held, 361 * so the address_list can not change. 362 */ 363 list_for_each_entry(addr, &bp->address_list, list) { 364 if (sctp_has_association(net, &addr->a, paddr)) 365 return 1; 366 } 367 368 return 0; 369 } 370 371 /* Do delayed input processing. This is scheduled by sctp_rcv(). 372 * This may be called on BH or task time. 373 */ 374 static void sctp_endpoint_bh_rcv(struct work_struct *work) 375 { 376 struct sctp_endpoint *ep = 377 container_of(work, struct sctp_endpoint, 378 base.inqueue.immediate); 379 struct sctp_association *asoc; 380 struct sock *sk; 381 struct net *net; 382 struct sctp_transport *transport; 383 struct sctp_chunk *chunk; 384 struct sctp_inq *inqueue; 385 sctp_subtype_t subtype; 386 enum sctp_state state; 387 int error = 0; 388 int first_time = 1; /* is this the first time through the loop */ 389 390 if (ep->base.dead) 391 return; 392 393 asoc = NULL; 394 inqueue = &ep->base.inqueue; 395 sk = ep->base.sk; 396 net = sock_net(sk); 397 398 while (NULL != (chunk = sctp_inq_pop(inqueue))) { 399 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type); 400 401 /* If the first chunk in the packet is AUTH, do special 402 * processing specified in Section 6.3 of SCTP-AUTH spec 403 */ 404 if (first_time && (subtype.chunk == SCTP_CID_AUTH)) { 405 struct sctp_chunkhdr *next_hdr; 406 407 next_hdr = sctp_inq_peek(inqueue); 408 if (!next_hdr) 409 goto normal; 410 411 /* If the next chunk is COOKIE-ECHO, skip the AUTH 412 * chunk while saving a pointer to it so we can do 413 * Authentication later (during cookie-echo 414 * processing). 415 */ 416 if (next_hdr->type == SCTP_CID_COOKIE_ECHO) { 417 chunk->auth_chunk = skb_clone(chunk->skb, 418 GFP_ATOMIC); 419 chunk->auth = 1; 420 continue; 421 } 422 } 423 normal: 424 /* We might have grown an association since last we 425 * looked, so try again. 426 * 427 * This happens when we've just processed our 428 * COOKIE-ECHO chunk. 429 */ 430 if (NULL == chunk->asoc) { 431 asoc = sctp_endpoint_lookup_assoc(ep, 432 sctp_source(chunk), 433 &transport); 434 chunk->asoc = asoc; 435 chunk->transport = transport; 436 } 437 438 state = asoc ? asoc->state : SCTP_STATE_CLOSED; 439 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth) 440 continue; 441 442 /* Remember where the last DATA chunk came from so we 443 * know where to send the SACK. 444 */ 445 if (asoc && sctp_chunk_is_data(chunk)) 446 asoc->peer.last_data_from = chunk->transport; 447 else { 448 SCTP_INC_STATS(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS); 449 if (asoc) 450 asoc->stats.ictrlchunks++; 451 } 452 453 if (chunk->transport) 454 chunk->transport->last_time_heard = ktime_get(); 455 456 error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state, 457 ep, asoc, chunk, GFP_ATOMIC); 458 459 if (error && chunk) 460 chunk->pdiscard = 1; 461 462 /* Check to see if the endpoint is freed in response to 463 * the incoming chunk. If so, get out of the while loop. 464 */ 465 if (!sctp_sk(sk)->ep) 466 break; 467 468 if (first_time) 469 first_time = 0; 470 } 471 } 472