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; 109 110 /* Remember who we are attached to. */ 111 ep->base.sk = sk; 112 sock_hold(ep->base.sk); 113 114 return ep; 115 116 nomem_shkey: 117 sctp_auth_free(ep); 118 nomem: 119 kfree(ep->digest); 120 return NULL; 121 122 } 123 124 /* Create a sctp_endpoint with all that boring stuff initialized. 125 * Returns NULL if there isn't enough memory. 126 */ 127 struct sctp_endpoint *sctp_endpoint_new(struct sock *sk, gfp_t gfp) 128 { 129 struct sctp_endpoint *ep; 130 131 /* Build a local endpoint. */ 132 ep = kzalloc(sizeof(*ep), gfp); 133 if (!ep) 134 goto fail; 135 136 if (!sctp_endpoint_init(ep, sk, gfp)) 137 goto fail_init; 138 139 SCTP_DBG_OBJCNT_INC(ep); 140 return ep; 141 142 fail_init: 143 kfree(ep); 144 fail: 145 return NULL; 146 } 147 148 /* Add an association to an endpoint. */ 149 void sctp_endpoint_add_asoc(struct sctp_endpoint *ep, 150 struct sctp_association *asoc) 151 { 152 struct sock *sk = ep->base.sk; 153 154 /* If this is a temporary association, don't bother 155 * since we'll be removing it shortly and don't 156 * want anyone to find it anyway. 157 */ 158 if (asoc->temp) 159 return; 160 161 /* Now just add it to our list of asocs */ 162 list_add_tail(&asoc->asocs, &ep->asocs); 163 164 /* Increment the backlog value for a TCP-style listening socket. */ 165 if (sctp_style(sk, TCP) && sctp_sstate(sk, LISTENING)) 166 sk->sk_ack_backlog++; 167 } 168 169 /* Free the endpoint structure. Delay cleanup until 170 * all users have released their reference count on this structure. 171 */ 172 void sctp_endpoint_free(struct sctp_endpoint *ep) 173 { 174 ep->base.dead = true; 175 176 inet_sk_set_state(ep->base.sk, SCTP_SS_CLOSED); 177 178 /* Unlink this endpoint, so we can't find it again! */ 179 sctp_unhash_endpoint(ep); 180 181 sctp_endpoint_put(ep); 182 } 183 184 /* Final destructor for endpoint. */ 185 static void sctp_endpoint_destroy(struct sctp_endpoint *ep) 186 { 187 struct sock *sk; 188 189 if (unlikely(!ep->base.dead)) { 190 WARN(1, "Attempt to destroy undead endpoint %p!\n", ep); 191 return; 192 } 193 194 /* Free the digest buffer */ 195 kfree(ep->digest); 196 197 /* SCTP-AUTH: Free up AUTH releated data such as shared keys 198 * chunks and hmacs arrays that were allocated 199 */ 200 sctp_auth_destroy_keys(&ep->endpoint_shared_keys); 201 sctp_auth_free(ep); 202 203 /* Cleanup. */ 204 sctp_inq_free(&ep->base.inqueue); 205 sctp_bind_addr_free(&ep->base.bind_addr); 206 207 memset(ep->secret_key, 0, sizeof(ep->secret_key)); 208 209 sk = ep->base.sk; 210 /* Remove and free the port */ 211 if (sctp_sk(sk)->bind_hash) 212 sctp_put_port(sk); 213 214 sctp_sk(sk)->ep = NULL; 215 /* Give up our hold on the sock */ 216 sock_put(sk); 217 218 kfree(ep); 219 SCTP_DBG_OBJCNT_DEC(ep); 220 } 221 222 /* Hold a reference to an endpoint. */ 223 void sctp_endpoint_hold(struct sctp_endpoint *ep) 224 { 225 refcount_inc(&ep->base.refcnt); 226 } 227 228 /* Release a reference to an endpoint and clean up if there are 229 * no more references. 230 */ 231 void sctp_endpoint_put(struct sctp_endpoint *ep) 232 { 233 if (refcount_dec_and_test(&ep->base.refcnt)) 234 sctp_endpoint_destroy(ep); 235 } 236 237 /* Is this the endpoint we are looking for? */ 238 struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep, 239 struct net *net, 240 const union sctp_addr *laddr) 241 { 242 struct sctp_endpoint *retval = NULL; 243 244 if ((htons(ep->base.bind_addr.port) == laddr->v4.sin_port) && 245 net_eq(sock_net(ep->base.sk), net)) { 246 if (sctp_bind_addr_match(&ep->base.bind_addr, laddr, 247 sctp_sk(ep->base.sk))) 248 retval = ep; 249 } 250 251 return retval; 252 } 253 254 /* Find the association that goes with this chunk. 255 * We lookup the transport from hashtable at first, then get association 256 * through t->assoc. 257 */ 258 struct sctp_association *sctp_endpoint_lookup_assoc( 259 const struct sctp_endpoint *ep, 260 const union sctp_addr *paddr, 261 struct sctp_transport **transport) 262 { 263 struct sctp_association *asoc = NULL; 264 struct sctp_transport *t; 265 266 *transport = NULL; 267 268 /* If the local port is not set, there can't be any associations 269 * on this endpoint. 270 */ 271 if (!ep->base.bind_addr.port) 272 return NULL; 273 274 rcu_read_lock(); 275 t = sctp_epaddr_lookup_transport(ep, paddr); 276 if (!t) 277 goto out; 278 279 *transport = t; 280 asoc = t->asoc; 281 out: 282 rcu_read_unlock(); 283 return asoc; 284 } 285 286 /* Look for any peeled off association from the endpoint that matches the 287 * given peer address. 288 */ 289 bool sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep, 290 const union sctp_addr *paddr) 291 { 292 struct sctp_sockaddr_entry *addr; 293 struct sctp_bind_addr *bp; 294 struct net *net = sock_net(ep->base.sk); 295 296 bp = &ep->base.bind_addr; 297 /* This function is called with the socket lock held, 298 * so the address_list can not change. 299 */ 300 list_for_each_entry(addr, &bp->address_list, list) { 301 if (sctp_has_association(net, &addr->a, paddr)) 302 return true; 303 } 304 305 return false; 306 } 307 308 /* Do delayed input processing. This is scheduled by sctp_rcv(). 309 * This may be called on BH or task time. 310 */ 311 static void sctp_endpoint_bh_rcv(struct work_struct *work) 312 { 313 struct sctp_endpoint *ep = 314 container_of(work, struct sctp_endpoint, 315 base.inqueue.immediate); 316 struct sctp_association *asoc; 317 struct sock *sk; 318 struct net *net; 319 struct sctp_transport *transport; 320 struct sctp_chunk *chunk; 321 struct sctp_inq *inqueue; 322 union sctp_subtype subtype; 323 enum sctp_state state; 324 int error = 0; 325 int first_time = 1; /* is this the first time through the loop */ 326 327 if (ep->base.dead) 328 return; 329 330 asoc = NULL; 331 inqueue = &ep->base.inqueue; 332 sk = ep->base.sk; 333 net = sock_net(sk); 334 335 while (NULL != (chunk = sctp_inq_pop(inqueue))) { 336 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type); 337 338 /* If the first chunk in the packet is AUTH, do special 339 * processing specified in Section 6.3 of SCTP-AUTH spec 340 */ 341 if (first_time && (subtype.chunk == SCTP_CID_AUTH)) { 342 struct sctp_chunkhdr *next_hdr; 343 344 next_hdr = sctp_inq_peek(inqueue); 345 if (!next_hdr) 346 goto normal; 347 348 /* If the next chunk is COOKIE-ECHO, skip the AUTH 349 * chunk while saving a pointer to it so we can do 350 * Authentication later (during cookie-echo 351 * processing). 352 */ 353 if (next_hdr->type == SCTP_CID_COOKIE_ECHO) { 354 chunk->auth_chunk = skb_clone(chunk->skb, 355 GFP_ATOMIC); 356 chunk->auth = 1; 357 continue; 358 } 359 } 360 normal: 361 /* We might have grown an association since last we 362 * looked, so try again. 363 * 364 * This happens when we've just processed our 365 * COOKIE-ECHO chunk. 366 */ 367 if (NULL == chunk->asoc) { 368 asoc = sctp_endpoint_lookup_assoc(ep, 369 sctp_source(chunk), 370 &transport); 371 chunk->asoc = asoc; 372 chunk->transport = transport; 373 } 374 375 state = asoc ? asoc->state : SCTP_STATE_CLOSED; 376 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth) 377 continue; 378 379 /* Remember where the last DATA chunk came from so we 380 * know where to send the SACK. 381 */ 382 if (asoc && sctp_chunk_is_data(chunk)) 383 asoc->peer.last_data_from = chunk->transport; 384 else { 385 SCTP_INC_STATS(sock_net(ep->base.sk), SCTP_MIB_INCTRLCHUNKS); 386 if (asoc) 387 asoc->stats.ictrlchunks++; 388 } 389 390 if (chunk->transport) 391 chunk->transport->last_time_heard = ktime_get(); 392 393 error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state, 394 ep, asoc, chunk, GFP_ATOMIC); 395 396 if (error && chunk) 397 chunk->pdiscard = 1; 398 399 /* Check to see if the endpoint is freed in response to 400 * the incoming chunk. If so, get out of the while loop. 401 */ 402 if (!sctp_sk(sk)->ep) 403 break; 404 405 if (first_time) 406 first_time = 0; 407 } 408 } 409