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 memset(ep, 0, sizeof(struct sctp_endpoint)); 73 74 ep->digest = kzalloc(SCTP_SIGNATURE_SIZE, gfp); 75 if (!ep->digest) 76 return NULL; 77 78 /* Initialize the base structure. */ 79 /* What type of endpoint are we? */ 80 ep->base.type = SCTP_EP_TYPE_SOCKET; 81 82 /* Initialize the basic object fields. */ 83 atomic_set(&ep->base.refcnt, 1); 84 ep->base.dead = 0; 85 ep->base.malloced = 1; 86 87 /* Create an input queue. */ 88 sctp_inq_init(&ep->base.inqueue); 89 90 /* Set its top-half handler */ 91 sctp_inq_set_th_handler(&ep->base.inqueue, sctp_endpoint_bh_rcv); 92 93 /* Initialize the bind addr area */ 94 sctp_bind_addr_init(&ep->base.bind_addr, 0); 95 rwlock_init(&ep->base.addr_lock); 96 97 /* Remember who we are attached to. */ 98 ep->base.sk = sk; 99 sock_hold(ep->base.sk); 100 101 /* Create the lists of associations. */ 102 INIT_LIST_HEAD(&ep->asocs); 103 104 /* Use SCTP specific send buffer space queues. */ 105 ep->sndbuf_policy = sctp_sndbuf_policy; 106 sk->sk_write_space = sctp_write_space; 107 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE); 108 109 /* Get the receive buffer policy for this endpoint */ 110 ep->rcvbuf_policy = sctp_rcvbuf_policy; 111 112 /* Initialize the secret key used with cookie. */ 113 get_random_bytes(&ep->secret_key[0], SCTP_SECRET_SIZE); 114 ep->last_key = ep->current_key = 0; 115 ep->key_changed_at = jiffies; 116 117 return ep; 118 } 119 120 /* Create a sctp_endpoint with all that boring stuff initialized. 121 * Returns NULL if there isn't enough memory. 122 */ 123 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp) 124 { 125 struct sctp_endpoint *ep; 126 127 /* Build a local endpoint. */ 128 ep = t_new(struct sctp_endpoint, gfp); 129 if (!ep) 130 goto fail; 131 if (!sctp_endpoint_init(ep, sk, gfp)) 132 goto fail_init; 133 ep->base.malloced = 1; 134 SCTP_DBG_OBJCNT_INC(ep); 135 return ep; 136 137 fail_init: 138 kfree(ep); 139 fail: 140 return NULL; 141 } 142 143 /* Add an association to an endpoint. */ 144 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep, 145 struct sctp_association *asoc) 146 { 147 struct sock *sk = ep->base.sk; 148 149 /* If this is a temporary association, don't bother 150 * since we'll be removing it shortly and don't 151 * want anyone to find it anyway. 152 */ 153 if (asoc->temp) 154 return; 155 156 /* Now just add it to our list of asocs */ 157 list_add_tail(&asoc->asocs, &ep->asocs); 158 159 /* Increment the backlog value for a TCP-style listening socket. */ 160 if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING)) 161 sk->sk_ack_backlog++; 162 } 163 164 /* Free the endpoint structure. Delay cleanup until 165 * all users have released their reference count on this structure. 166 */ 167 void sctp_endpoint_free(struct sctp_endpoint *ep) 168 { 169 ep->base.dead = 1; 170 171 ep->base.sk->sk_state = SCTP_SS_CLOSED; 172 173 /* Unlink this endpoint, so we can't find it again! */ 174 sctp_unhash_endpoint(ep); 175 176 sctp_endpoint_put(ep); 177 } 178 179 /* Final destructor for endpoint. */ 180 static void sctp_endpoint_destroy(struct sctp_endpoint *ep) 181 { 182 SCTP_ASSERT(ep->base.dead, "Endpoint is not dead", return); 183 184 /* Free up the HMAC transform. */ 185 crypto_free_hash(sctp_sk(ep->base.sk)->hmac); 186 187 /* Free the digest buffer */ 188 kfree(ep->digest); 189 190 /* Cleanup. */ 191 sctp_inq_free(&ep->base.inqueue); 192 sctp_bind_addr_free(&ep->base.bind_addr); 193 194 /* Remove and free the port */ 195 if (sctp_sk(ep->base.sk)->bind_hash) 196 sctp_put_port(ep->base.sk); 197 198 /* Give up our hold on the sock. */ 199 if (ep->base.sk) 200 sock_put(ep->base.sk); 201 202 /* Finally, free up our memory. */ 203 if (ep->base.malloced) { 204 kfree(ep); 205 SCTP_DBG_OBJCNT_DEC(ep); 206 } 207 } 208 209 /* Hold a reference to an endpoint. */ 210 void sctp_endpoint_hold(struct sctp_endpoint *ep) 211 { 212 atomic_inc(&ep->base.refcnt); 213 } 214 215 /* Release a reference to an endpoint and clean up if there are 216 * no more references. 217 */ 218 void sctp_endpoint_put(struct sctp_endpoint *ep) 219 { 220 if (atomic_dec_and_test(&ep->base.refcnt)) 221 sctp_endpoint_destroy(ep); 222 } 223 224 /* Is this the endpoint we are looking for? */ 225 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep, 226 const union sctp_addr *laddr) 227 { 228 struct sctp_endpoint *retval; 229 230 sctp_read_lock(&ep->base.addr_lock); 231 if (htons(ep->base.bind_addr.port) == laddr->v4.sin_port) { 232 if (sctp_bind_addr_match(&ep->base.bind_addr, laddr, 233 sctp_sk(ep->base.sk))) { 234 retval = ep; 235 goto out; 236 } 237 } 238 239 retval = NULL; 240 241 out: 242 sctp_read_unlock(&ep->base.addr_lock); 243 return retval; 244 } 245 246 /* Find the association that goes with this chunk. 247 * We do a linear search of the associations for this endpoint. 248 * We return the matching transport address too. 249 */ 250 static struct sctp_association *__sctp_endpoint_lookup_assoc( 251 const struct sctp_endpoint *ep, 252 const union sctp_addr *paddr, 253 struct sctp_transport **transport) 254 { 255 int rport; 256 struct sctp_association *asoc; 257 struct list_head *pos; 258 259 rport = ntohs(paddr->v4.sin_port); 260 261 list_for_each(pos, &ep->asocs) { 262 asoc = list_entry(pos, struct sctp_association, asocs); 263 if (rport == asoc->peer.port) { 264 sctp_read_lock(&asoc->base.addr_lock); 265 *transport = sctp_assoc_lookup_paddr(asoc, paddr); 266 sctp_read_unlock(&asoc->base.addr_lock); 267 268 if (*transport) 269 return asoc; 270 } 271 } 272 273 *transport = NULL; 274 return NULL; 275 } 276 277 /* Lookup association on an endpoint based on a peer address. BH-safe. */ 278 struct sctp_association *sctp_endpoint_lookup_assoc( 279 const struct sctp_endpoint *ep, 280 const union sctp_addr *paddr, 281 struct sctp_transport **transport) 282 { 283 struct sctp_association *asoc; 284 285 sctp_local_bh_disable(); 286 asoc = __sctp_endpoint_lookup_assoc(ep, paddr, transport); 287 sctp_local_bh_enable(); 288 289 return asoc; 290 } 291 292 /* Look for any peeled off association from the endpoint that matches the 293 * given peer address. 294 */ 295 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep, 296 const union sctp_addr *paddr) 297 { 298 struct list_head *pos; 299 struct sctp_sockaddr_entry *addr; 300 struct sctp_bind_addr *bp; 301 302 sctp_read_lock(&ep->base.addr_lock); 303 bp = &ep->base.bind_addr; 304 list_for_each(pos, &bp->address_list) { 305 addr = list_entry(pos, struct sctp_sockaddr_entry, list); 306 if (sctp_has_association(&addr->a, paddr)) { 307 sctp_read_unlock(&ep->base.addr_lock); 308 return 1; 309 } 310 } 311 sctp_read_unlock(&ep->base.addr_lock); 312 313 return 0; 314 } 315 316 /* Do delayed input processing. This is scheduled by sctp_rcv(). 317 * This may be called on BH or task time. 318 */ 319 static void sctp_endpoint_bh_rcv(struct work_struct *work) 320 { 321 struct sctp_endpoint *ep = 322 container_of(work, struct sctp_endpoint, 323 base.inqueue.immediate); 324 struct sctp_association *asoc; 325 struct sock *sk; 326 struct sctp_transport *transport; 327 struct sctp_chunk *chunk; 328 struct sctp_inq *inqueue; 329 sctp_subtype_t subtype; 330 sctp_state_t state; 331 int error = 0; 332 333 if (ep->base.dead) 334 return; 335 336 asoc = NULL; 337 inqueue = &ep->base.inqueue; 338 sk = ep->base.sk; 339 340 while (NULL != (chunk = sctp_inq_pop(inqueue))) { 341 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type); 342 343 /* We might have grown an association since last we 344 * looked, so try again. 345 * 346 * This happens when we've just processed our 347 * COOKIE-ECHO chunk. 348 */ 349 if (NULL == chunk->asoc) { 350 asoc = sctp_endpoint_lookup_assoc(ep, 351 sctp_source(chunk), 352 &transport); 353 chunk->asoc = asoc; 354 chunk->transport = transport; 355 } 356 357 state = asoc ? asoc->state : SCTP_STATE_CLOSED; 358 359 /* Remember where the last DATA chunk came from so we 360 * know where to send the SACK. 361 */ 362 if (asoc && sctp_chunk_is_data(chunk)) 363 asoc->peer.last_data_from = chunk->transport; 364 else 365 SCTP_INC_STATS(SCTP_MIB_INCTRLCHUNKS); 366 367 if (chunk->transport) 368 chunk->transport->last_time_heard = jiffies; 369 370 error = sctp_do_sm(SCTP_EVENT_T_CHUNK, subtype, state, 371 ep, asoc, chunk, GFP_ATOMIC); 372 373 if (error && chunk) 374 chunk->pdiscard = 1; 375 376 /* Check to see if the endpoint is freed in response to 377 * the incoming chunk. If so, get out of the while loop. 378 */ 379 if (!sctp_sk(sk)->ep) 380 break; 381 } 382 } 383