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 <linux/crypto.h> 46 #include <net/sock.h> 47 #include <net/ipv6.h> 48 #include <net/sctp/sctp.h> 49 #include <net/sctp/sm.h> 50 51 /* Forward declarations for internal helpers. */ 52 static void sctp_endpoint_bh_rcv(struct work_struct *work); 53 54 /* 55 * Initialize the base fields of the endpoint structure. 56 */ 57 static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep, 58 struct sock *sk, 59 gfp_t gfp) 60 { 61 struct net *net = sock_net(sk); 62 struct sctp_hmac_algo_param *auth_hmacs = NULL; 63 struct sctp_chunks_param *auth_chunks = NULL; 64 struct sctp_shared_key *null_key; 65 int err; 66 67 ep->digest = kzalloc(SCTP_SIGNATURE_SIZE, gfp); 68 if (!ep->digest) 69 return NULL; 70 71 ep->auth_enable = net->sctp.auth_enable; 72 if (ep->auth_enable) { 73 /* Allocate space for HMACS and CHUNKS authentication 74 * variables. There are arrays that we encode directly 75 * into parameters to make the rest of the operations easier. 76 */ 77 auth_hmacs = kzalloc(sizeof(sctp_hmac_algo_param_t) + 78 sizeof(__u16) * SCTP_AUTH_NUM_HMACS, gfp); 79 if (!auth_hmacs) 80 goto nomem; 81 82 auth_chunks = kzalloc(sizeof(sctp_chunks_param_t) + 83 SCTP_NUM_CHUNK_TYPES, gfp); 84 if (!auth_chunks) 85 goto nomem; 86 87 /* Initialize the HMACS parameter. 88 * SCTP-AUTH: Section 3.3 89 * Every endpoint supporting SCTP chunk authentication MUST 90 * support the HMAC based on the SHA-1 algorithm. 91 */ 92 auth_hmacs->param_hdr.type = SCTP_PARAM_HMAC_ALGO; 93 auth_hmacs->param_hdr.length = 94 htons(sizeof(sctp_paramhdr_t) + 2); 95 auth_hmacs->hmac_ids[0] = htons(SCTP_AUTH_HMAC_ID_SHA1); 96 97 /* Initialize the CHUNKS parameter */ 98 auth_chunks->param_hdr.type = SCTP_PARAM_CHUNKS; 99 auth_chunks->param_hdr.length = htons(sizeof(sctp_paramhdr_t)); 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(sctp_paramhdr_t) + 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 atomic_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; 167 168 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 goto out; 335 t = sctp_epaddr_lookup_transport(ep, paddr); 336 if (!t) 337 goto out; 338 339 *transport = t; 340 asoc = t->asoc; 341 out: 342 return asoc; 343 } 344 345 /* Look for any peeled off association from the endpoint that matches the 346 * given peer address. 347 */ 348 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep, 349 const union sctp_addr *paddr) 350 { 351 struct sctp_sockaddr_entry *addr; 352 struct sctp_bind_addr *bp; 353 struct net *net = sock_net(ep->base.sk); 354 355 bp = &ep->base.bind_addr; 356 /* This function is called with the socket lock held, 357 * so the address_list can not change. 358 */ 359 list_for_each_entry(addr, &bp->address_list, list) { 360 if (sctp_has_association(net, &addr->a, paddr)) 361 return 1; 362 } 363 364 return 0; 365 } 366 367 /* Do delayed input processing. This is scheduled by sctp_rcv(). 368 * This may be called on BH or task time. 369 */ 370 static void sctp_endpoint_bh_rcv(struct work_struct *work) 371 { 372 struct sctp_endpoint *ep = 373 container_of(work, struct sctp_endpoint, 374 base.inqueue.immediate); 375 struct sctp_association *asoc; 376 struct sock *sk; 377 struct net *net; 378 struct sctp_transport *transport; 379 struct sctp_chunk *chunk; 380 struct sctp_inq *inqueue; 381 sctp_subtype_t subtype; 382 sctp_state_t state; 383 int error = 0; 384 int first_time = 1; /* is this the first time through the loop */ 385 386 if (ep->base.dead) 387 return; 388 389 asoc = NULL; 390 inqueue = &ep->base.inqueue; 391 sk = ep->base.sk; 392 net = sock_net(sk); 393 394 while (NULL != (chunk = sctp_inq_pop(inqueue))) { 395 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type); 396 397 /* If the first chunk in the packet is AUTH, do special 398 * processing specified in Section 6.3 of SCTP-AUTH spec 399 */ 400 if (first_time && (subtype.chunk == SCTP_CID_AUTH)) { 401 struct sctp_chunkhdr *next_hdr; 402 403 next_hdr = sctp_inq_peek(inqueue); 404 if (!next_hdr) 405 goto normal; 406 407 /* If the next chunk is COOKIE-ECHO, skip the AUTH 408 * chunk while saving a pointer to it so we can do 409 * Authentication later (during cookie-echo 410 * processing). 411 */ 412 if (next_hdr->type == SCTP_CID_COOKIE_ECHO) { 413 chunk->auth_chunk = skb_clone(chunk->skb, 414 GFP_ATOMIC); 415 chunk->auth = 1; 416 continue; 417 } 418 } 419 normal: 420 /* We might have grown an association since last we 421 * looked, so try again. 422 * 423 * This happens when we've just processed our 424 * COOKIE-ECHO chunk. 425 */ 426 if (NULL == chunk->asoc) { 427 asoc = sctp_endpoint_lookup_assoc(ep, 428 sctp_source(chunk), 429 &transport); 430 chunk->asoc = asoc; 431 chunk->transport = transport; 432 } 433 434 state = asoc ? asoc->state : SCTP_STATE_CLOSED; 435 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth) 436 continue; 437 438 /* Remember where the last DATA chunk came from so we 439 * know where to send the SACK. 440 */ 441 if (asoc && sctp_chunk_is_data(chunk)) 442 asoc->peer.last_data_from = chunk->transport; 443 else { 444 SCTP_INC_STATS(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS); 445 if (asoc) 446 asoc->stats.ictrlchunks++; 447 } 448 449 if (chunk->transport) 450 chunk->transport->last_time_heard = ktime_get(); 451 452 error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state, 453 ep, asoc, chunk, GFP_ATOMIC); 454 455 if (error && chunk) 456 chunk->pdiscard = 1; 457 458 /* Check to see if the endpoint is freed in response to 459 * the incoming chunk. If so, get out of the while loop. 460 */ 461 if (!sctp_sk(sk)->ep) 462 break; 463 464 if (first_time) 465 first_time = 0; 466 } 467 } 468