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 sk = ep->base.sk; 272 /* Remove and free the port */ 273 if (sctp_sk(sk)->bind_hash) 274 sctp_put_port(sk); 275 276 sctp_sk(sk)->ep = NULL; 277 /* Give up our hold on the sock */ 278 sock_put(sk); 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 } 471