1 /* SCTP kernel reference 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 reference Implementation 10 * 11 * This abstraction represents an SCTP endpoint. 12 * 13 * This file is part of the implementation of the add-IP extension, 14 * based on <draft-ietf-tsvwg-addip-sctp-02.txt> June 29, 2001, 15 * for the SCTP kernel reference Implementation. 16 * 17 * The SCTP reference implementation is free software; 18 * you can redistribute it and/or modify it under the terms of 19 * the GNU General Public License as published by 20 * the Free Software Foundation; either version 2, or (at your option) 21 * any later version. 22 * 23 * The SCTP reference implementation is distributed in the hope that it 24 * will be useful, but WITHOUT ANY WARRANTY; without even the implied 25 * ************************ 26 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. 27 * See the GNU General Public License for more details. 28 * 29 * You should have received a copy of the GNU General Public License 30 * along with GNU CC; see the file COPYING. If not, write to 31 * the Free Software Foundation, 59 Temple Place - Suite 330, 32 * Boston, MA 02111-1307, USA. 33 * 34 * Please send any bug reports or fixes you make to the 35 * email address(es): 36 * lksctp developers <lksctp-developers@lists.sourceforge.net> 37 * 38 * Or submit a bug report through the following website: 39 * http://www.sf.net/projects/lksctp 40 * 41 * Written or modified by: 42 * La Monte H.P. Yarroll <piggy@acm.org> 43 * Karl Knutson <karl@athena.chicago.il.us> 44 * Jon Grimm <jgrimm@austin.ibm.com> 45 * Daisy Chang <daisyc@us.ibm.com> 46 * Dajiang Zhang <dajiang.zhang@nokia.com> 47 * 48 * Any bugs reported given to us we will try to fix... any fixes shared will 49 * be incorporated into the next SCTP release. 50 */ 51 52 #include <linux/types.h> 53 #include <linux/slab.h> 54 #include <linux/in.h> 55 #include <linux/random.h> /* get_random_bytes() */ 56 #include <linux/crypto.h> 57 #include <net/sock.h> 58 #include <net/ipv6.h> 59 #include <net/sctp/sctp.h> 60 #include <net/sctp/sm.h> 61 62 /* Forward declarations for internal helpers. */ 63 static void sctp_endpoint_bh_rcv(struct work_struct *work); 64 65 /* 66 * Initialize the base fields of the endpoint structure. 67 */ 68 static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep, 69 struct sock *sk, 70 gfp_t gfp) 71 { 72 struct sctp_hmac_algo_param *auth_hmacs = NULL; 73 struct sctp_chunks_param *auth_chunks = NULL; 74 struct sctp_shared_key *null_key; 75 int err; 76 77 memset(ep, 0, sizeof(struct sctp_endpoint)); 78 79 ep->digest = kzalloc(SCTP_SIGNATURE_SIZE, gfp); 80 if (!ep->digest) 81 return NULL; 82 83 if (sctp_auth_enable) { 84 /* Allocate space for HMACS and CHUNKS authentication 85 * variables. There are arrays that we encode directly 86 * into parameters to make the rest of the operations easier. 87 */ 88 auth_hmacs = kzalloc(sizeof(sctp_hmac_algo_param_t) + 89 sizeof(__u16) * SCTP_AUTH_NUM_HMACS, gfp); 90 if (!auth_hmacs) 91 goto nomem; 92 93 auth_chunks = kzalloc(sizeof(sctp_chunks_param_t) + 94 SCTP_NUM_CHUNK_TYPES, gfp); 95 if (!auth_chunks) 96 goto nomem; 97 98 /* Initialize the HMACS parameter. 99 * SCTP-AUTH: Section 3.3 100 * Every endpoint supporting SCTP chunk authentication MUST 101 * support the HMAC based on the SHA-1 algorithm. 102 */ 103 auth_hmacs->param_hdr.type = SCTP_PARAM_HMAC_ALGO; 104 auth_hmacs->param_hdr.length = 105 htons(sizeof(sctp_paramhdr_t) + 2); 106 auth_hmacs->hmac_ids[0] = htons(SCTP_AUTH_HMAC_ID_SHA1); 107 108 /* Initialize the CHUNKS parameter */ 109 auth_chunks->param_hdr.type = SCTP_PARAM_CHUNKS; 110 111 /* If the Add-IP functionality is enabled, we must 112 * authenticate, ASCONF and ASCONF-ACK chunks 113 */ 114 if (sctp_addip_enable) { 115 auth_chunks->chunks[0] = SCTP_CID_ASCONF; 116 auth_chunks->chunks[1] = SCTP_CID_ASCONF_ACK; 117 auth_chunks->param_hdr.length = 118 htons(sizeof(sctp_paramhdr_t) + 2); 119 } 120 } 121 122 /* Initialize the base structure. */ 123 /* What type of endpoint are we? */ 124 ep->base.type = SCTP_EP_TYPE_SOCKET; 125 126 /* Initialize the basic object fields. */ 127 atomic_set(&ep->base.refcnt, 1); 128 ep->base.dead = 0; 129 ep->base.malloced = 1; 130 131 /* Create an input queue. */ 132 sctp_inq_init(&ep->base.inqueue); 133 134 /* Set its top-half handler */ 135 sctp_inq_set_th_handler(&ep->base.inqueue, sctp_endpoint_bh_rcv); 136 137 /* Initialize the bind addr area */ 138 sctp_bind_addr_init(&ep->base.bind_addr, 0); 139 140 /* Remember who we are attached to. */ 141 ep->base.sk = sk; 142 sock_hold(ep->base.sk); 143 144 /* Create the lists of associations. */ 145 INIT_LIST_HEAD(&ep->asocs); 146 147 /* Use SCTP specific send buffer space queues. */ 148 ep->sndbuf_policy = sctp_sndbuf_policy; 149 150 sk->sk_write_space = sctp_write_space; 151 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE); 152 153 /* Get the receive buffer policy for this endpoint */ 154 ep->rcvbuf_policy = sctp_rcvbuf_policy; 155 156 /* Initialize the secret key used with cookie. */ 157 get_random_bytes(&ep->secret_key[0], SCTP_SECRET_SIZE); 158 ep->last_key = ep->current_key = 0; 159 ep->key_changed_at = jiffies; 160 161 /* SCTP-AUTH extensions*/ 162 INIT_LIST_HEAD(&ep->endpoint_shared_keys); 163 null_key = sctp_auth_shkey_create(0, GFP_KERNEL); 164 if (!null_key) 165 goto nomem; 166 167 list_add(&null_key->key_list, &ep->endpoint_shared_keys); 168 169 /* Allocate and initialize transorms arrays for suported HMACs. */ 170 err = sctp_auth_init_hmacs(ep, gfp); 171 if (err) 172 goto nomem_hmacs; 173 174 /* Add the null key to the endpoint shared keys list and 175 * set the hmcas and chunks pointers. 176 */ 177 ep->auth_hmacs_list = auth_hmacs; 178 ep->auth_chunk_list = auth_chunks; 179 180 return ep; 181 182 nomem_hmacs: 183 sctp_auth_destroy_keys(&ep->endpoint_shared_keys); 184 nomem: 185 /* Free all allocations */ 186 kfree(auth_hmacs); 187 kfree(auth_chunks); 188 kfree(ep->digest); 189 return NULL; 190 191 } 192 193 /* Create a sctp_endpoint with all that boring stuff initialized. 194 * Returns NULL if there isn't enough memory. 195 */ 196 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp) 197 { 198 struct sctp_endpoint *ep; 199 200 /* Build a local endpoint. */ 201 ep = t_new(struct sctp_endpoint, gfp); 202 if (!ep) 203 goto fail; 204 if (!sctp_endpoint_init(ep, sk, gfp)) 205 goto fail_init; 206 ep->base.malloced = 1; 207 SCTP_DBG_OBJCNT_INC(ep); 208 return ep; 209 210 fail_init: 211 kfree(ep); 212 fail: 213 return NULL; 214 } 215 216 /* Add an association to an endpoint. */ 217 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep, 218 struct sctp_association *asoc) 219 { 220 struct sock *sk = ep->base.sk; 221 222 /* If this is a temporary association, don't bother 223 * since we'll be removing it shortly and don't 224 * want anyone to find it anyway. 225 */ 226 if (asoc->temp) 227 return; 228 229 /* Now just add it to our list of asocs */ 230 list_add_tail(&asoc->asocs, &ep->asocs); 231 232 /* Increment the backlog value for a TCP-style listening socket. */ 233 if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING)) 234 sk->sk_ack_backlog++; 235 } 236 237 /* Free the endpoint structure. Delay cleanup until 238 * all users have released their reference count on this structure. 239 */ 240 void sctp_endpoint_free(struct sctp_endpoint *ep) 241 { 242 ep->base.dead = 1; 243 244 ep->base.sk->sk_state = SCTP_SS_CLOSED; 245 246 /* Unlink this endpoint, so we can't find it again! */ 247 sctp_unhash_endpoint(ep); 248 249 sctp_endpoint_put(ep); 250 } 251 252 /* Final destructor for endpoint. */ 253 static void sctp_endpoint_destroy(struct sctp_endpoint *ep) 254 { 255 SCTP_ASSERT(ep->base.dead, "Endpoint is not dead", return); 256 257 /* Free up the HMAC transform. */ 258 crypto_free_hash(sctp_sk(ep->base.sk)->hmac); 259 260 /* Free the digest buffer */ 261 kfree(ep->digest); 262 263 /* SCTP-AUTH: Free up AUTH releated data such as shared keys 264 * chunks and hmacs arrays that were allocated 265 */ 266 sctp_auth_destroy_keys(&ep->endpoint_shared_keys); 267 kfree(ep->auth_hmacs_list); 268 kfree(ep->auth_chunk_list); 269 270 /* AUTH - Free any allocated HMAC transform containers */ 271 sctp_auth_destroy_hmacs(ep->auth_hmacs); 272 273 /* Cleanup. */ 274 sctp_inq_free(&ep->base.inqueue); 275 sctp_bind_addr_free(&ep->base.bind_addr); 276 277 /* Remove and free the port */ 278 if (sctp_sk(ep->base.sk)->bind_hash) 279 sctp_put_port(ep->base.sk); 280 281 /* Give up our hold on the sock. */ 282 if (ep->base.sk) 283 sock_put(ep->base.sk); 284 285 /* Finally, free up our memory. */ 286 if (ep->base.malloced) { 287 kfree(ep); 288 SCTP_DBG_OBJCNT_DEC(ep); 289 } 290 } 291 292 /* Hold a reference to an endpoint. */ 293 void sctp_endpoint_hold(struct sctp_endpoint *ep) 294 { 295 atomic_inc(&ep->base.refcnt); 296 } 297 298 /* Release a reference to an endpoint and clean up if there are 299 * no more references. 300 */ 301 void sctp_endpoint_put(struct sctp_endpoint *ep) 302 { 303 if (atomic_dec_and_test(&ep->base.refcnt)) 304 sctp_endpoint_destroy(ep); 305 } 306 307 /* Is this the endpoint we are looking for? */ 308 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep, 309 const union sctp_addr *laddr) 310 { 311 struct sctp_endpoint *retval = NULL; 312 313 if (htons(ep->base.bind_addr.port) == laddr->v4.sin_port) { 314 if (sctp_bind_addr_match(&ep->base.bind_addr, laddr, 315 sctp_sk(ep->base.sk))) 316 retval = ep; 317 } 318 319 return retval; 320 } 321 322 /* Find the association that goes with this chunk. 323 * We do a linear search of the associations for this endpoint. 324 * We return the matching transport address too. 325 */ 326 static struct sctp_association *__sctp_endpoint_lookup_assoc( 327 const struct sctp_endpoint *ep, 328 const union sctp_addr *paddr, 329 struct sctp_transport **transport) 330 { 331 int rport; 332 struct sctp_association *asoc; 333 struct list_head *pos; 334 335 rport = ntohs(paddr->v4.sin_port); 336 337 list_for_each(pos, &ep->asocs) { 338 asoc = list_entry(pos, struct sctp_association, asocs); 339 if (rport == asoc->peer.port) { 340 *transport = sctp_assoc_lookup_paddr(asoc, paddr); 341 342 if (*transport) 343 return asoc; 344 } 345 } 346 347 *transport = NULL; 348 return NULL; 349 } 350 351 /* Lookup association on an endpoint based on a peer address. BH-safe. */ 352 struct sctp_association *sctp_endpoint_lookup_assoc( 353 const struct sctp_endpoint *ep, 354 const union sctp_addr *paddr, 355 struct sctp_transport **transport) 356 { 357 struct sctp_association *asoc; 358 359 sctp_local_bh_disable(); 360 asoc = __sctp_endpoint_lookup_assoc(ep, paddr, transport); 361 sctp_local_bh_enable(); 362 363 return asoc; 364 } 365 366 /* Look for any peeled off association from the endpoint that matches the 367 * given peer address. 368 */ 369 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep, 370 const union sctp_addr *paddr) 371 { 372 struct sctp_sockaddr_entry *addr; 373 struct sctp_bind_addr *bp; 374 375 bp = &ep->base.bind_addr; 376 /* This function is called with the socket lock held, 377 * so the address_list can not change. 378 */ 379 list_for_each_entry(addr, &bp->address_list, list) { 380 if (sctp_has_association(&addr->a, paddr)) 381 return 1; 382 } 383 384 return 0; 385 } 386 387 /* Do delayed input processing. This is scheduled by sctp_rcv(). 388 * This may be called on BH or task time. 389 */ 390 static void sctp_endpoint_bh_rcv(struct work_struct *work) 391 { 392 struct sctp_endpoint *ep = 393 container_of(work, struct sctp_endpoint, 394 base.inqueue.immediate); 395 struct sctp_association *asoc; 396 struct sock *sk; 397 struct sctp_transport *transport; 398 struct sctp_chunk *chunk; 399 struct sctp_inq *inqueue; 400 sctp_subtype_t subtype; 401 sctp_state_t state; 402 int error = 0; 403 int first_time = 1; /* is this the first time through the looop */ 404 405 if (ep->base.dead) 406 return; 407 408 asoc = NULL; 409 inqueue = &ep->base.inqueue; 410 sk = ep->base.sk; 411 412 while (NULL != (chunk = sctp_inq_pop(inqueue))) { 413 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type); 414 415 /* If the first chunk in the packet is AUTH, do special 416 * processing specified in Section 6.3 of SCTP-AUTH spec 417 */ 418 if (first_time && (subtype.chunk == SCTP_CID_AUTH)) { 419 struct sctp_chunkhdr *next_hdr; 420 421 next_hdr = sctp_inq_peek(inqueue); 422 if (!next_hdr) 423 goto normal; 424 425 /* If the next chunk is COOKIE-ECHO, skip the AUTH 426 * chunk while saving a pointer to it so we can do 427 * Authentication later (during cookie-echo 428 * processing). 429 */ 430 if (next_hdr->type == SCTP_CID_COOKIE_ECHO) { 431 chunk->auth_chunk = skb_clone(chunk->skb, 432 GFP_ATOMIC); 433 chunk->auth = 1; 434 continue; 435 } 436 } 437 normal: 438 /* We might have grown an association since last we 439 * looked, so try again. 440 * 441 * This happens when we've just processed our 442 * COOKIE-ECHO chunk. 443 */ 444 if (NULL == chunk->asoc) { 445 asoc = sctp_endpoint_lookup_assoc(ep, 446 sctp_source(chunk), 447 &transport); 448 chunk->asoc = asoc; 449 chunk->transport = transport; 450 } 451 452 state = asoc ? asoc->state : SCTP_STATE_CLOSED; 453 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth) 454 continue; 455 456 /* Remember where the last DATA chunk came from so we 457 * know where to send the SACK. 458 */ 459 if (asoc && sctp_chunk_is_data(chunk)) 460 asoc->peer.last_data_from = chunk->transport; 461 else 462 SCTP_INC_STATS(SCTP_MIB_INCTRLCHUNKS); 463 464 if (chunk->transport) 465 chunk->transport->last_time_heard = jiffies; 466 467 error = sctp_do_sm(SCTP_EVENT_T_CHUNK, subtype, state, 468 ep, asoc, chunk, GFP_ATOMIC); 469 470 if (error && chunk) 471 chunk->pdiscard = 1; 472 473 /* Check to see if the endpoint is freed in response to 474 * the incoming chunk. If so, get out of the while loop. 475 */ 476 if (!sctp_sk(sk)->ep) 477 break; 478 479 if (first_time) 480 first_time = 0; 481 } 482 } 483