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. */ 36static void sctp_endpoint_bh_rcv(struct work_struct *work); 37 38/* 39 * Initialize the base fields of the endpoint structure. 40 */ 41static 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 118nomem_shkey: 119 sctp_auth_free(ep); 120nomem: 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 */ 129struct 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 144fail_init: 145 kfree(ep); 146fail: 147 return NULL; 148} 149 150/* Add an association to an endpoint. */ 151void 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 */ 174void 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. */ 187static void sctp_endpoint_destroy_rcu(struct rcu_head *head) 188{ 189 struct sctp_endpoint *ep = container_of(head, struct sctp_endpoint, rcu); 190 struct sock *sk = ep->base.sk; 191 192 sctp_sk(sk)->ep = NULL; 193 sock_put(sk); 194 195 kfree(ep); 196 SCTP_DBG_OBJCNT_DEC(ep); 197} 198 199static void sctp_endpoint_destroy(struct sctp_endpoint *ep) 200{ 201 struct sock *sk; 202 203 if (unlikely(!ep->base.dead)) { 204 WARN(1, "Attempt to destroy undead endpoint %p!\n", ep); 205 return; 206 } 207 208 /* Free the digest buffer */ 209 kfree(ep->digest); 210 211 /* SCTP-AUTH: Free up AUTH releated data such as shared keys 212 * chunks and hmacs arrays that were allocated 213 */ 214 sctp_auth_destroy_keys(&ep->endpoint_shared_keys); 215 sctp_auth_free(ep); 216 217 /* Cleanup. */ 218 sctp_inq_free(&ep->base.inqueue); 219 sctp_bind_addr_free(&ep->base.bind_addr); 220 221 memset(ep->secret_key, 0, sizeof(ep->secret_key)); 222 223 sk = ep->base.sk; 224 /* Remove and free the port */ 225 if (sctp_sk(sk)->bind_hash) 226 sctp_put_port(sk); 227 228 call_rcu(&ep->rcu, sctp_endpoint_destroy_rcu); 229} 230 231/* Hold a reference to an endpoint. */ 232int sctp_endpoint_hold(struct sctp_endpoint *ep) 233{ 234 return refcount_inc_not_zero(&ep->base.refcnt); 235} 236 237/* Release a reference to an endpoint and clean up if there are 238 * no more references. 239 */ 240void sctp_endpoint_put(struct sctp_endpoint *ep) 241{ 242 if (refcount_dec_and_test(&ep->base.refcnt)) 243 sctp_endpoint_destroy(ep); 244} 245 246/* Is this the endpoint we are looking for? */ 247struct sctp_endpoint *sctp_endpoint_is_match(struct sctp_endpoint *ep, 248 struct net *net, 249 const union sctp_addr *laddr) 250{ 251 struct sctp_endpoint *retval = NULL; 252 253 if ((htons(ep->base.bind_addr.port) == laddr->v4.sin_port) && 254 net_eq(ep->base.net, net)) { 255 if (sctp_bind_addr_match(&ep->base.bind_addr, laddr, 256 sctp_sk(ep->base.sk))) 257 retval = ep; 258 } 259 260 return retval; 261} 262 263/* Find the association that goes with this chunk. 264 * We lookup the transport from hashtable at first, then get association 265 * through t->assoc. 266 */ 267struct sctp_association *sctp_endpoint_lookup_assoc( 268 const struct sctp_endpoint *ep, 269 const union sctp_addr *paddr, 270 struct sctp_transport **transport) 271{ 272 struct sctp_association *asoc = NULL; 273 struct sctp_transport *t; 274 275 *transport = NULL; 276 277 /* If the local port is not set, there can't be any associations 278 * on this endpoint. 279 */ 280 if (!ep->base.bind_addr.port) 281 return NULL; 282 283 rcu_read_lock(); 284 t = sctp_epaddr_lookup_transport(ep, paddr); 285 if (!t) 286 goto out; 287 288 *transport = t; 289 asoc = t->asoc; 290out: 291 rcu_read_unlock(); 292 return asoc; 293} 294 295/* Look for any peeled off association from the endpoint that matches the 296 * given peer address. 297 */ 298bool sctp_endpoint_is_peeled_off(struct sctp_endpoint *ep, 299 const union sctp_addr *paddr) 300{ 301 struct sctp_sockaddr_entry *addr; 302 struct net *net = ep->base.net; 303 struct sctp_bind_addr *bp; 304 305 bp = &ep->base.bind_addr; 306 /* This function is called with the socket lock held, 307 * so the address_list can not change. 308 */ 309 list_for_each_entry(addr, &bp->address_list, list) { 310 if (sctp_has_association(net, &addr->a, paddr)) 311 return true; 312 } 313 314 return false; 315} 316 317/* Do delayed input processing. This is scheduled by sctp_rcv(). 318 * This may be called on BH or task time. 319 */ 320static void sctp_endpoint_bh_rcv(struct work_struct *work) 321{ 322 struct sctp_endpoint *ep = 323 container_of(work, struct sctp_endpoint, 324 base.inqueue.immediate); 325 struct sctp_association *asoc; 326 struct sock *sk; 327 struct net *net; 328 struct sctp_transport *transport; 329 struct sctp_chunk *chunk; 330 struct sctp_inq *inqueue; 331 union sctp_subtype subtype; 332 enum sctp_state state; 333 int error = 0; 334 int first_time = 1; /* is this the first time through the loop */ 335 336 if (ep->base.dead) 337 return; 338 339 asoc = NULL; 340 inqueue = &ep->base.inqueue; 341 sk = ep->base.sk; 342 net = sock_net(sk); 343 344 while (NULL != (chunk = sctp_inq_pop(inqueue))) { 345 subtype = SCTP_ST_CHUNK(chunk->chunk_hdr->type); 346 347 /* If the first chunk in the packet is AUTH, do special 348 * processing specified in Section 6.3 of SCTP-AUTH spec 349 */ 350 if (first_time && (subtype.chunk == SCTP_CID_AUTH)) { 351 struct sctp_chunkhdr *next_hdr; 352 353 next_hdr = sctp_inq_peek(inqueue); 354 if (!next_hdr) 355 goto normal; 356 357 /* If the next chunk is COOKIE-ECHO, skip the AUTH 358 * chunk while saving a pointer to it so we can do 359 * Authentication later (during cookie-echo 360 * processing). 361 */ 362 if (next_hdr->type == SCTP_CID_COOKIE_ECHO) { 363 chunk->auth_chunk = skb_clone(chunk->skb, 364 GFP_ATOMIC); 365 chunk->auth = 1; 366 continue; 367 } 368 } 369normal: 370 /* We might have grown an association since last we 371 * looked, so try again. 372 * 373 * This happens when we've just processed our 374 * COOKIE-ECHO chunk. 375 */ 376 if (NULL == chunk->asoc) { 377 asoc = sctp_endpoint_lookup_assoc(ep, 378 sctp_source(chunk), 379 &transport); 380 chunk->asoc = asoc; 381 chunk->transport = transport; 382 } 383 384 state = asoc ? asoc->state : SCTP_STATE_CLOSED; 385 if (sctp_auth_recv_cid(subtype.chunk, asoc) && !chunk->auth) 386 continue; 387 388 /* Remember where the last DATA chunk came from so we 389 * know where to send the SACK. 390 */ 391 if (asoc && sctp_chunk_is_data(chunk)) 392 asoc->peer.last_data_from = chunk->transport; 393 else { 394 SCTP_INC_STATS(ep->base.net, SCTP_MIB_INCTRLCHUNKS); 395 if (asoc) 396 asoc->stats.ictrlchunks++; 397 } 398 399 if (chunk->transport) 400 chunk->transport->last_time_heard = ktime_get(); 401 402 error = sctp_do_sm(net, SCTP_EVENT_T_CHUNK, subtype, state, 403 ep, asoc, chunk, GFP_ATOMIC); 404 405 if (error && chunk) 406 chunk->pdiscard = 1; 407 408 /* Check to see if the endpoint is freed in response to 409 * the incoming chunk. If so, get out of the while loop. 410 */ 411 if (!sctp_sk(sk)->ep) 412 break; 413 414 if (first_time) 415 first_time = 0; 416 } 417} 418