1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* SCTP kernel implementation 3 * Copyright (c) 1999-2000 Cisco, Inc. 4 * Copyright (c) 1999-2001 Motorola, Inc. 5 * Copyright (c) 2001-2002 International Business Machines, Corp. 6 * Copyright (c) 2001 Intel Corp. 7 * Copyright (c) 2001 Nokia, Inc. 8 * Copyright (c) 2001 La Monte H.P. Yarroll 9 * 10 * This file is part of the SCTP kernel implementation 11 * 12 * This abstraction represents an SCTP endpoint. 13 * 14 * Please send any bug reports or fixes you make to the 15 * email address(es): 16 * lksctp developers <linux-sctp@vger.kernel.org> 17 * 18 * Written or modified by: 19 * La Monte H.P. Yarroll <piggy@acm.org> 20 * Karl Knutson <karl@athena.chicago.il.us> 21 * Jon Grimm <jgrimm@austin.ibm.com> 22 * Daisy Chang <daisyc@us.ibm.com> 23 * Dajiang Zhang <dajiang.zhang@nokia.com> 24 */ 25 26 #include <linux/types.h> 27 #include <linux/slab.h> 28 #include <linux/in.h> 29 #include <linux/random.h> /* get_random_bytes() */ 30 #include <net/sock.h> 31 #include <net/ipv6.h> 32 #include <net/sctp/sctp.h> 33 #include <net/sctp/sm.h> 34 35 /* Forward declarations for internal helpers. */ 36 static void sctp_endpoint_bh_rcv(struct work_struct *work); 37 38 /* 39 * Initialize the base fields of the endpoint structure. 40 */ 41 static struct sctp_endpoint *sctp_endpoint_init(struct sctp_endpoint *ep, 42 struct sock *sk, 43 gfp_t gfp) 44 { 45 struct net *net = sock_net(sk); 46 struct sctp_shared_key *null_key; 47 48 ep->digest = kzalloc(SCTP_SIGNATURE_SIZE, gfp); 49 if (!ep->digest) 50 return NULL; 51 52 ep->asconf_enable = net->sctp.addip_enable; 53 ep->auth_enable = net->sctp.auth_enable; 54 if (ep->auth_enable) { 55 if (sctp_auth_init(ep, gfp)) 56 goto nomem; 57 if (ep->asconf_enable) { 58 sctp_auth_ep_add_chunkid(ep, SCTP_CID_ASCONF); 59 sctp_auth_ep_add_chunkid(ep, SCTP_CID_ASCONF_ACK); 60 } 61 } 62 63 /* Initialize the base structure. */ 64 /* What type of endpoint are we? */ 65 ep->base.type = SCTP_EP_TYPE_SOCKET; 66 67 /* Initialize the basic object fields. */ 68 refcount_set(&ep->base.refcnt, 1); 69 ep->base.dead = false; 70 71 /* Create an input queue. */ 72 sctp_inq_init(&ep->base.inqueue); 73 74 /* Set its top-half handler */ 75 sctp_inq_set_th_handler(&ep->base.inqueue, sctp_endpoint_bh_rcv); 76 77 /* Initialize the bind addr area */ 78 sctp_bind_addr_init(&ep->base.bind_addr, 0); 79 80 /* Create the lists of associations. */ 81 INIT_LIST_HEAD(&ep->asocs); 82 83 /* Use SCTP specific send buffer space queues. */ 84 ep->sndbuf_policy = net->sctp.sndbuf_policy; 85 86 sk->sk_data_ready = sctp_data_ready; 87 sk->sk_write_space = sctp_write_space; 88 sock_set_flag(sk, SOCK_USE_WRITE_QUEUE); 89 90 /* Get the receive buffer policy for this endpoint */ 91 ep->rcvbuf_policy = net->sctp.rcvbuf_policy; 92 93 /* Initialize the secret key used with cookie. */ 94 get_random_bytes(ep->secret_key, sizeof(ep->secret_key)); 95 96 /* SCTP-AUTH extensions*/ 97 INIT_LIST_HEAD(&ep->endpoint_shared_keys); 98 null_key = sctp_auth_shkey_create(0, gfp); 99 if (!null_key) 100 goto nomem_shkey; 101 102 list_add(&null_key->key_list, &ep->endpoint_shared_keys); 103 104 /* Add the null key to the endpoint shared keys list and 105 * set the hmcas and chunks pointers. 106 */ 107 ep->prsctp_enable = net->sctp.prsctp_enable; 108 ep->reconf_enable = net->sctp.reconf_enable; 109 ep->ecn_enable = net->sctp.ecn_enable; 110 111 /* Remember who we are attached to. */ 112 ep->base.sk = sk; 113 ep->base.net = sock_net(sk); 114 sock_hold(ep->base.sk); 115 116 return ep; 117 118 nomem_shkey: 119 sctp_auth_free(ep); 120 nomem: 121 kfree(ep->digest); 122 return NULL; 123 124 } 125 126 /* Create a sctp_endpoint with all that boring stuff initialized. 127 * Returns NULL if there isn't enough memory. 128 */ 129 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp) 130 { 131 struct sctp_endpoint *ep; 132 133 /* Build a local endpoint. */ 134 ep = kzalloc(sizeof(*ep), gfp); 135 if (!ep) 136 goto fail; 137 138 if (!sctp_endpoint_init(ep, sk, gfp)) 139 goto fail_init; 140 141 SCTP_DBG_OBJCNT_INC(ep); 142 return ep; 143 144 fail_init: 145 kfree(ep); 146 fail: 147 return NULL; 148 } 149 150 /* Add an association to an endpoint. */ 151 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep, 152 struct sctp_association *asoc) 153 { 154 struct sock *sk = ep->base.sk; 155 156 /* If this is a temporary association, don't bother 157 * since we'll be removing it shortly and don't 158 * want anyone to find it anyway. 159 */ 160 if (asoc->temp) 161 return; 162 163 /* Now just add it to our list of asocs */ 164 list_add_tail(&asoc->asocs, &ep->asocs); 165 166 /* Increment the backlog value for a TCP-style listening socket. */ 167 if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING)) 168 sk_acceptq_added(sk); 169 } 170 171 /* Free the endpoint structure. Delay cleanup until 172 * all users have released their reference count on this structure. 173 */ 174 void sctp_endpoint_free(struct sctp_endpoint *ep) 175 { 176 ep->base.dead = true; 177 178 inet_sk_set_state(ep->base.sk, SCTP_SS_CLOSED); 179 180 /* Unlink this endpoint, so we can't find it again! */ 181 sctp_unhash_endpoint(ep); 182 183 sctp_endpoint_put(ep); 184 } 185 186 /* Final destructor for endpoint. */ 187 static void sctp_endpoint_destroy(struct sctp_endpoint *ep) 188 { 189 struct sock *sk; 190 191 if (unlikely(!ep->base.dead)) { 192 WARN(1, "Attempt to destroy undead endpoint %p!\n", ep); 193 return; 194 } 195 196 /* Free the digest buffer */ 197 kfree(ep->digest); 198 199 /* SCTP-AUTH: Free up AUTH releated data such as shared keys 200 * chunks and hmacs arrays that were allocated 201 */ 202 sctp_auth_destroy_keys(&ep->endpoint_shared_keys); 203 sctp_auth_free(ep); 204 205 /* Cleanup. */ 206 sctp_inq_free(&ep->base.inqueue); 207 sctp_bind_addr_free(&ep->base.bind_addr); 208 209 memset(ep->secret_key, 0, sizeof(ep->secret_key)); 210 211 sk = ep->base.sk; 212 /* Remove and free the port */ 213 if (sctp_sk(sk)->bind_hash) 214 sctp_put_port(sk); 215 216 sctp_sk(sk)->ep = NULL; 217 /* Give up our hold on the sock */ 218 sock_put(sk); 219 220 kfree(ep); 221 SCTP_DBG_OBJCNT_DEC(ep); 222 } 223 224 /* Hold a reference to an endpoint. */ 225 void sctp_endpoint_hold(struct sctp_endpoint *ep) 226 { 227 refcount_inc(&ep->base.refcnt); 228 } 229 230 /* Release a reference to an endpoint and clean up if there are 231 * no more references. 232 */ 233 void sctp_endpoint_put(struct sctp_endpoint *ep) 234 { 235 if (refcount_dec_and_test(&ep->base.refcnt)) 236 sctp_endpoint_destroy(ep); 237 } 238 239 /* Is this the endpoint we are looking for? */ 240 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep, 241 struct net *net, 242 const union sctp_addr *laddr) 243 { 244 struct sctp_endpoint *retval = NULL; 245 246 if ((htons(ep->base.bind_addr.port) == laddr->v4.sin_port) && 247 net_eq(ep->base.net, net)) { 248 if (sctp_bind_addr_match(&ep->base.bind_addr, laddr, 249 sctp_sk(ep->base.sk))) 250 retval = ep; 251 } 252 253 return retval; 254 } 255 256 /* Find the association that goes with this chunk. 257 * We lookup the transport from hashtable at first, then get association 258 * through t->assoc. 259 */ 260 struct sctp_association *sctp_endpoint_lookup_assoc( 261 const struct sctp_endpoint *ep, 262 const union sctp_addr *paddr, 263 struct sctp_transport **transport) 264 { 265 struct sctp_association *asoc = NULL; 266 struct sctp_transport *t; 267 268 *transport = NULL; 269 270 /* If the local port is not set, there can't be any associations 271 * on this endpoint. 272 */ 273 if (!ep->base.bind_addr.port) 274 return NULL; 275 276 rcu_read_lock(); 277 t = sctp_epaddr_lookup_transport(ep, paddr); 278 if (!t) 279 goto out; 280 281 *transport = t; 282 asoc = t->asoc; 283 out: 284 rcu_read_unlock(); 285 return asoc; 286 } 287 288 /* Look for any peeled off association from the endpoint that matches the 289 * given peer address. 290 */ 291 bool sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep, 292 const union sctp_addr *paddr) 293 { 294 struct sctp_sockaddr_entry *addr; 295 struct net *net = ep->base.net; 296 struct sctp_bind_addr *bp; 297 298 bp = &ep->base.bind_addr; 299 /* This function is called with the socket lock held, 300 * so the address_list can not change. 301 */ 302 list_for_each_entry(addr, &bp->address_list, list) { 303 if (sctp_has_association(net, &addr->a, paddr)) 304 return true; 305 } 306 307 return false; 308 } 309 310 /* Do delayed input processing. This is scheduled by sctp_rcv(). 311 * This may be called on BH or task time. 312 */ 313 static void sctp_endpoint_bh_rcv(struct work_struct *work) 314 { 315 struct sctp_endpoint *ep = 316 container_of(work, struct sctp_endpoint, 317 base.inqueue.immediate); 318 struct sctp_association *asoc; 319 struct sock *sk; 320 struct net *net; 321 struct sctp_transport *transport; 322 struct sctp_chunk *chunk; 323 struct sctp_inq *inqueue; 324 union sctp_subtype subtype; 325 enum sctp_state state; 326 int error = 0; 327 int first_time = 1; /* is this the first time through the loop */ 328 329 if (ep->base.dead) 330 return; 331 332 asoc = NULL; 333 inqueue = &ep->base.inqueue; 334 sk = ep->base.sk; 335 net = sock_net(sk); 336 337 while (NULL != (chunk = sctp_inq_pop(inqueue))) { 338 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type); 339 340 /* If the first chunk in the packet is AUTH, do special 341 * processing specified in Section 6.3 of SCTP-AUTH spec 342 */ 343 if (first_time && (subtype.chunk == SCTP_CID_AUTH)) { 344 struct sctp_chunkhdr *next_hdr; 345 346 next_hdr = sctp_inq_peek(inqueue); 347 if (!next_hdr) 348 goto normal; 349 350 /* If the next chunk is COOKIE-ECHO, skip the AUTH 351 * chunk while saving a pointer to it so we can do 352 * Authentication later (during cookie-echo 353 * processing). 354 */ 355 if (next_hdr->type == SCTP_CID_COOKIE_ECHO) { 356 chunk->auth_chunk = skb_clone(chunk->skb, 357 GFP_ATOMIC); 358 chunk->auth = 1; 359 continue; 360 } 361 } 362 normal: 363 /* We might have grown an association since last we 364 * looked, so try again. 365 * 366 * This happens when we've just processed our 367 * COOKIE-ECHO chunk. 368 */ 369 if (NULL == chunk->asoc) { 370 asoc = sctp_endpoint_lookup_assoc(ep, 371 sctp_source(chunk), 372 &transport); 373 chunk->asoc = asoc; 374 chunk->transport = transport; 375 } 376 377 state = asoc ? asoc->state : SCTP_STATE_CLOSED; 378 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth) 379 continue; 380 381 /* Remember where the last DATA chunk came from so we 382 * know where to send the SACK. 383 */ 384 if (asoc && sctp_chunk_is_data(chunk)) 385 asoc->peer.last_data_from = chunk->transport; 386 else { 387 SCTP_INC_STATS(ep->base.net, SCTP_MIB_INCTRLCHUNKS); 388 if (asoc) 389 asoc->stats.ictrlchunks++; 390 } 391 392 if (chunk->transport) 393 chunk->transport->last_time_heard = ktime_get(); 394 395 error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state, 396 ep, asoc, chunk, GFP_ATOMIC); 397 398 if (error && chunk) 399 chunk->pdiscard = 1; 400 401 /* Check to see if the endpoint is freed in response to 402 * the incoming chunk. If so, get out of the while loop. 403 */ 404 if (!sctp_sk(sk)->ep) 405 break; 406 407 if (first_time) 408 first_time = 0; 409 } 410 } 411