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 sock_hold(ep->base.sk); 114 115 return ep; 116 117 nomem_shkey: 118 sctp_auth_free(ep); 119 nomem: 120 kfree(ep->digest); 121 return NULL; 122 123 } 124 125 /* Create a sctp_endpoint with all that boring stuff initialized. 126 * Returns NULL if there isn't enough memory. 127 */ 128 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp) 129 { 130 struct sctp_endpoint *ep; 131 132 /* Build a local endpoint. */ 133 ep = kzalloc(sizeof(*ep), gfp); 134 if (!ep) 135 goto fail; 136 137 if (!sctp_endpoint_init(ep, sk, gfp)) 138 goto fail_init; 139 140 SCTP_DBG_OBJCNT_INC(ep); 141 return ep; 142 143 fail_init: 144 kfree(ep); 145 fail: 146 return NULL; 147 } 148 149 /* Add an association to an endpoint. */ 150 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep, 151 struct sctp_association *asoc) 152 { 153 struct sock *sk = ep->base.sk; 154 155 /* If this is a temporary association, don't bother 156 * since we'll be removing it shortly and don't 157 * want anyone to find it anyway. 158 */ 159 if (asoc->temp) 160 return; 161 162 /* Now just add it to our list of asocs */ 163 list_add_tail(&asoc->asocs, &ep->asocs); 164 165 /* Increment the backlog value for a TCP-style listening socket. */ 166 if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING)) 167 sk->sk_ack_backlog++; 168 } 169 170 /* Free the endpoint structure. Delay cleanup until 171 * all users have released their reference count on this structure. 172 */ 173 void sctp_endpoint_free(struct sctp_endpoint *ep) 174 { 175 ep->base.dead = true; 176 177 inet_sk_set_state(ep->base.sk, SCTP_SS_CLOSED); 178 179 /* Unlink this endpoint, so we can't find it again! */ 180 sctp_unhash_endpoint(ep); 181 182 sctp_endpoint_put(ep); 183 } 184 185 /* Final destructor for endpoint. */ 186 static void sctp_endpoint_destroy(struct sctp_endpoint *ep) 187 { 188 struct sock *sk; 189 190 if (unlikely(!ep->base.dead)) { 191 WARN(1, "Attempt to destroy undead endpoint %p!\n", ep); 192 return; 193 } 194 195 /* Free the digest buffer */ 196 kfree(ep->digest); 197 198 /* SCTP-AUTH: Free up AUTH releated data such as shared keys 199 * chunks and hmacs arrays that were allocated 200 */ 201 sctp_auth_destroy_keys(&ep->endpoint_shared_keys); 202 sctp_auth_free(ep); 203 204 /* Cleanup. */ 205 sctp_inq_free(&ep->base.inqueue); 206 sctp_bind_addr_free(&ep->base.bind_addr); 207 208 memset(ep->secret_key, 0, sizeof(ep->secret_key)); 209 210 sk = ep->base.sk; 211 /* Remove and free the port */ 212 if (sctp_sk(sk)->bind_hash) 213 sctp_put_port(sk); 214 215 sctp_sk(sk)->ep = NULL; 216 /* Give up our hold on the sock */ 217 sock_put(sk); 218 219 kfree(ep); 220 SCTP_DBG_OBJCNT_DEC(ep); 221 } 222 223 /* Hold a reference to an endpoint. */ 224 void sctp_endpoint_hold(struct sctp_endpoint *ep) 225 { 226 refcount_inc(&ep->base.refcnt); 227 } 228 229 /* Release a reference to an endpoint and clean up if there are 230 * no more references. 231 */ 232 void sctp_endpoint_put(struct sctp_endpoint *ep) 233 { 234 if (refcount_dec_and_test(&ep->base.refcnt)) 235 sctp_endpoint_destroy(ep); 236 } 237 238 /* Is this the endpoint we are looking for? */ 239 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep, 240 struct net *net, 241 const union sctp_addr *laddr) 242 { 243 struct sctp_endpoint *retval = NULL; 244 245 if ((htons(ep->base.bind_addr.port) == laddr->v4.sin_port) && 246 net_eq(sock_net(ep->base.sk), net)) { 247 if (sctp_bind_addr_match(&ep->base.bind_addr, laddr, 248 sctp_sk(ep->base.sk))) 249 retval = ep; 250 } 251 252 return retval; 253 } 254 255 /* Find the association that goes with this chunk. 256 * We lookup the transport from hashtable at first, then get association 257 * through t->assoc. 258 */ 259 struct sctp_association *sctp_endpoint_lookup_assoc( 260 const struct sctp_endpoint *ep, 261 const union sctp_addr *paddr, 262 struct sctp_transport **transport) 263 { 264 struct sctp_association *asoc = NULL; 265 struct sctp_transport *t; 266 267 *transport = NULL; 268 269 /* If the local port is not set, there can't be any associations 270 * on this endpoint. 271 */ 272 if (!ep->base.bind_addr.port) 273 return NULL; 274 275 rcu_read_lock(); 276 t = sctp_epaddr_lookup_transport(ep, paddr); 277 if (!t) 278 goto out; 279 280 *transport = t; 281 asoc = t->asoc; 282 out: 283 rcu_read_unlock(); 284 return asoc; 285 } 286 287 /* Look for any peeled off association from the endpoint that matches the 288 * given peer address. 289 */ 290 bool sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep, 291 const union sctp_addr *paddr) 292 { 293 struct sctp_sockaddr_entry *addr; 294 struct sctp_bind_addr *bp; 295 struct net *net = sock_net(ep->base.sk); 296 297 bp = &ep->base.bind_addr; 298 /* This function is called with the socket lock held, 299 * so the address_list can not change. 300 */ 301 list_for_each_entry(addr, &bp->address_list, list) { 302 if (sctp_has_association(net, &addr->a, paddr)) 303 return true; 304 } 305 306 return false; 307 } 308 309 /* Do delayed input processing. This is scheduled by sctp_rcv(). 310 * This may be called on BH or task time. 311 */ 312 static void sctp_endpoint_bh_rcv(struct work_struct *work) 313 { 314 struct sctp_endpoint *ep = 315 container_of(work, struct sctp_endpoint, 316 base.inqueue.immediate); 317 struct sctp_association *asoc; 318 struct sock *sk; 319 struct net *net; 320 struct sctp_transport *transport; 321 struct sctp_chunk *chunk; 322 struct sctp_inq *inqueue; 323 union sctp_subtype subtype; 324 enum sctp_state state; 325 int error = 0; 326 int first_time = 1; /* is this the first time through the loop */ 327 328 if (ep->base.dead) 329 return; 330 331 asoc = NULL; 332 inqueue = &ep->base.inqueue; 333 sk = ep->base.sk; 334 net = sock_net(sk); 335 336 while (NULL != (chunk = sctp_inq_pop(inqueue))) { 337 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type); 338 339 /* If the first chunk in the packet is AUTH, do special 340 * processing specified in Section 6.3 of SCTP-AUTH spec 341 */ 342 if (first_time && (subtype.chunk == SCTP_CID_AUTH)) { 343 struct sctp_chunkhdr *next_hdr; 344 345 next_hdr = sctp_inq_peek(inqueue); 346 if (!next_hdr) 347 goto normal; 348 349 /* If the next chunk is COOKIE-ECHO, skip the AUTH 350 * chunk while saving a pointer to it so we can do 351 * Authentication later (during cookie-echo 352 * processing). 353 */ 354 if (next_hdr->type == SCTP_CID_COOKIE_ECHO) { 355 chunk->auth_chunk = skb_clone(chunk->skb, 356 GFP_ATOMIC); 357 chunk->auth = 1; 358 continue; 359 } 360 } 361 normal: 362 /* We might have grown an association since last we 363 * looked, so try again. 364 * 365 * This happens when we've just processed our 366 * COOKIE-ECHO chunk. 367 */ 368 if (NULL == chunk->asoc) { 369 asoc = sctp_endpoint_lookup_assoc(ep, 370 sctp_source(chunk), 371 &transport); 372 chunk->asoc = asoc; 373 chunk->transport = transport; 374 } 375 376 state = asoc ? asoc->state : SCTP_STATE_CLOSED; 377 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth) 378 continue; 379 380 /* Remember where the last DATA chunk came from so we 381 * know where to send the SACK. 382 */ 383 if (asoc && sctp_chunk_is_data(chunk)) 384 asoc->peer.last_data_from = chunk->transport; 385 else { 386 SCTP_INC_STATS(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS); 387 if (asoc) 388 asoc->stats.ictrlchunks++; 389 } 390 391 if (chunk->transport) 392 chunk->transport->last_time_heard = ktime_get(); 393 394 error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state, 395 ep, asoc, chunk, GFP_ATOMIC); 396 397 if (error && chunk) 398 chunk->pdiscard = 1; 399 400 /* Check to see if the endpoint is freed in response to 401 * the incoming chunk. If so, get out of the while loop. 402 */ 403 if (!sctp_sk(sk)->ep) 404 break; 405 406 if (first_time) 407 first_time = 0; 408 } 409 } 410