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