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/sched.h> 54 #include <linux/slab.h> 55 #include <linux/in.h> 56 #include <linux/random.h> /* get_random_bytes() */ 57 #include <linux/crypto.h> 58 #include <net/sock.h> 59 #include <net/ipv6.h> 60 #include <net/sctp/sctp.h> 61 #include <net/sctp/sm.h> 62 63 /* Forward declarations for internal helpers. */ 64 static void sctp_endpoint_bh_rcv(struct sctp_endpoint *ep); 65 66 /* 67 * Initialize the base fields of the endpoint structure. 68 */ 69 static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep, 70 struct sock *sk, 71 gfp_t gfp) 72 { 73 memset(ep, 0, sizeof(struct sctp_endpoint)); 74 75 ep->digest = kzalloc(SCTP_SIGNATURE_SIZE, gfp); 76 if (!ep->digest) 77 return NULL; 78 79 /* Initialize the base structure. */ 80 /* What type of endpoint are we? */ 81 ep->base.type = SCTP_EP_TYPE_SOCKET; 82 83 /* Initialize the basic object fields. */ 84 atomic_set(&ep->base.refcnt, 1); 85 ep->base.dead = 0; 86 ep->base.malloced = 1; 87 88 /* Create an input queue. */ 89 sctp_inq_init(&ep->base.inqueue); 90 91 /* Set its top-half handler */ 92 sctp_inq_set_th_handler(&ep->base.inqueue, 93 (void (*)(void *))sctp_endpoint_bh_rcv, ep); 94 95 /* Initialize the bind addr area */ 96 sctp_bind_addr_init(&ep->base.bind_addr, 0); 97 rwlock_init(&ep->base.addr_lock); 98 99 /* Remember who we are attached to. */ 100 ep->base.sk = sk; 101 sock_hold(ep->base.sk); 102 103 /* Create the lists of associations. */ 104 INIT_LIST_HEAD(&ep->asocs); 105 106 /* Use SCTP specific send buffer space queues. */ 107 ep->sndbuf_policy = sctp_sndbuf_policy; 108 sk->sk_write_space = sctp_write_space; 109 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE); 110 111 /* Get the receive buffer policy for this endpoint */ 112 ep->rcvbuf_policy = sctp_rcvbuf_policy; 113 114 /* Initialize the secret key used with cookie. */ 115 get_random_bytes(&ep->secret_key[0], SCTP_SECRET_SIZE); 116 ep->last_key = ep->current_key = 0; 117 ep->key_changed_at = jiffies; 118 119 return ep; 120 } 121 122 /* Create a sctp_endpoint with all that boring stuff initialized. 123 * Returns NULL if there isn't enough memory. 124 */ 125 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp) 126 { 127 struct sctp_endpoint *ep; 128 129 /* Build a local endpoint. */ 130 ep = t_new(struct sctp_endpoint, gfp); 131 if (!ep) 132 goto fail; 133 if (!sctp_endpoint_init(ep, sk, gfp)) 134 goto fail_init; 135 ep->base.malloced = 1; 136 SCTP_DBG_OBJCNT_INC(ep); 137 return ep; 138 139 fail_init: 140 kfree(ep); 141 fail: 142 return NULL; 143 } 144 145 /* Add an association to an endpoint. */ 146 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep, 147 struct sctp_association *asoc) 148 { 149 struct sock *sk = ep->base.sk; 150 151 /* If this is a temporary association, don't bother 152 * since we'll be removing it shortly and don't 153 * want anyone to find it anyway. 154 */ 155 if (asoc->temp) 156 return; 157 158 /* Now just add it to our list of asocs */ 159 list_add_tail(&asoc->asocs, &ep->asocs); 160 161 /* Increment the backlog value for a TCP-style listening socket. */ 162 if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING)) 163 sk->sk_ack_backlog++; 164 } 165 166 /* Free the endpoint structure. Delay cleanup until 167 * all users have released their reference count on this structure. 168 */ 169 void sctp_endpoint_free(struct sctp_endpoint *ep) 170 { 171 ep->base.dead = 1; 172 173 ep->base.sk->sk_state = SCTP_SS_CLOSED; 174 175 /* Unlink this endpoint, so we can't find it again! */ 176 sctp_unhash_endpoint(ep); 177 178 sctp_endpoint_put(ep); 179 } 180 181 /* Final destructor for endpoint. */ 182 static void sctp_endpoint_destroy(struct sctp_endpoint *ep) 183 { 184 SCTP_ASSERT(ep->base.dead, "Endpoint is not dead", return); 185 186 /* Free up the HMAC transform. */ 187 crypto_free_hash(sctp_sk(ep->base.sk)->hmac); 188 189 /* Free the digest buffer */ 190 kfree(ep->digest); 191 192 /* Cleanup. */ 193 sctp_inq_free(&ep->base.inqueue); 194 sctp_bind_addr_free(&ep->base.bind_addr); 195 196 /* Remove and free the port */ 197 if (sctp_sk(ep->base.sk)->bind_hash) 198 sctp_put_port(ep->base.sk); 199 200 /* Give up our hold on the sock. */ 201 if (ep->base.sk) 202 sock_put(ep->base.sk); 203 204 /* Finally, free up our memory. */ 205 if (ep->base.malloced) { 206 kfree(ep); 207 SCTP_DBG_OBJCNT_DEC(ep); 208 } 209 } 210 211 /* Hold a reference to an endpoint. */ 212 void sctp_endpoint_hold(struct sctp_endpoint *ep) 213 { 214 atomic_inc(&ep->base.refcnt); 215 } 216 217 /* Release a reference to an endpoint and clean up if there are 218 * no more references. 219 */ 220 void sctp_endpoint_put(struct sctp_endpoint *ep) 221 { 222 if (atomic_dec_and_test(&ep->base.refcnt)) 223 sctp_endpoint_destroy(ep); 224 } 225 226 /* Is this the endpoint we are looking for? */ 227 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep, 228 const union sctp_addr *laddr) 229 { 230 struct sctp_endpoint *retval; 231 232 sctp_read_lock(&ep->base.addr_lock); 233 if (htons(ep->base.bind_addr.port) == laddr->v4.sin_port) { 234 if (sctp_bind_addr_match(&ep->base.bind_addr, laddr, 235 sctp_sk(ep->base.sk))) { 236 retval = ep; 237 goto out; 238 } 239 } 240 241 retval = NULL; 242 243 out: 244 sctp_read_unlock(&ep->base.addr_lock); 245 return retval; 246 } 247 248 /* Find the association that goes with this chunk. 249 * We do a linear search of the associations for this endpoint. 250 * We return the matching transport address too. 251 */ 252 static struct sctp_association *__sctp_endpoint_lookup_assoc( 253 const struct sctp_endpoint *ep, 254 const union sctp_addr *paddr, 255 struct sctp_transport **transport) 256 { 257 int rport; 258 struct sctp_association *asoc; 259 struct list_head *pos; 260 union sctp_addr tmp; 261 flip_to_n(&tmp, paddr); 262 263 rport = paddr->v4.sin_port; 264 265 list_for_each(pos, &ep->asocs) { 266 asoc = list_entry(pos, struct sctp_association, asocs); 267 if (rport == asoc->peer.port) { 268 sctp_read_lock(&asoc->base.addr_lock); 269 *transport = sctp_assoc_lookup_paddr(asoc, &tmp); 270 sctp_read_unlock(&asoc->base.addr_lock); 271 272 if (*transport) 273 return asoc; 274 } 275 } 276 277 *transport = NULL; 278 return NULL; 279 } 280 281 /* Lookup association on an endpoint based on a peer address. BH-safe. */ 282 struct sctp_association *sctp_endpoint_lookup_assoc( 283 const struct sctp_endpoint *ep, 284 const union sctp_addr *paddr, 285 struct sctp_transport **transport) 286 { 287 struct sctp_association *asoc; 288 289 sctp_local_bh_disable(); 290 asoc = __sctp_endpoint_lookup_assoc(ep, paddr, transport); 291 sctp_local_bh_enable(); 292 293 return asoc; 294 } 295 296 /* Look for any peeled off association from the endpoint that matches the 297 * given peer address. 298 */ 299 int sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep, 300 const union sctp_addr *paddr) 301 { 302 struct list_head *pos; 303 struct sctp_sockaddr_entry *addr; 304 struct sctp_bind_addr *bp; 305 306 sctp_read_lock(&ep->base.addr_lock); 307 bp = &ep->base.bind_addr; 308 list_for_each(pos, &bp->address_list) { 309 addr = list_entry(pos, struct sctp_sockaddr_entry, list); 310 if (sctp_has_association(&addr->a_h, paddr)) { 311 sctp_read_unlock(&ep->base.addr_lock); 312 return 1; 313 } 314 } 315 sctp_read_unlock(&ep->base.addr_lock); 316 317 return 0; 318 } 319 320 /* Do delayed input processing. This is scheduled by sctp_rcv(). 321 * This may be called on BH or task time. 322 */ 323 static void sctp_endpoint_bh_rcv(struct sctp_endpoint *ep) 324 { 325 struct sctp_association *asoc; 326 struct sock *sk; 327 struct sctp_transport *transport; 328 struct sctp_chunk *chunk; 329 struct sctp_inq *inqueue; 330 sctp_subtype_t subtype; 331 sctp_state_t state; 332 int error = 0; 333 334 if (ep->base.dead) 335 return; 336 337 asoc = NULL; 338 inqueue = &ep->base.inqueue; 339 sk = ep->base.sk; 340 341 while (NULL != (chunk = sctp_inq_pop(inqueue))) { 342 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type); 343 344 /* We might have grown an association since last we 345 * looked, so try again. 346 * 347 * This happens when we've just processed our 348 * COOKIE-ECHO chunk. 349 */ 350 if (NULL == chunk->asoc) { 351 asoc = sctp_endpoint_lookup_assoc(ep, 352 sctp_source(chunk), 353 &transport); 354 chunk->asoc = asoc; 355 chunk->transport = transport; 356 } 357 358 state = asoc ? asoc->state : SCTP_STATE_CLOSED; 359 360 /* Remember where the last DATA chunk came from so we 361 * know where to send the SACK. 362 */ 363 if (asoc && sctp_chunk_is_data(chunk)) 364 asoc->peer.last_data_from = chunk->transport; 365 else 366 SCTP_INC_STATS(SCTP_MIB_INCTRLCHUNKS); 367 368 if (chunk->transport) 369 chunk->transport->last_time_heard = jiffies; 370 371 error = sctp_do_sm(SCTP_EVENT_T_CHUNK, subtype, state, 372 ep, asoc, chunk, GFP_ATOMIC); 373 374 if (error && chunk) 375 chunk->pdiscard = 1; 376 377 /* Check to see if the endpoint is freed in response to 378 * the incoming chunk. If so, get out of the while loop. 379 */ 380 if (!sctp_sk(sk)->ep) 381 break; 382 } 383 } 384