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