1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* Local endpoint object management 3 * 4 * Copyright (C) 2016 Red Hat, Inc. All Rights Reserved. 5 * Written by David Howells (dhowells@redhat.com) 6 */ 7 8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 9 10 #include <linux/module.h> 11 #include <linux/net.h> 12 #include <linux/skbuff.h> 13 #include <linux/slab.h> 14 #include <linux/udp.h> 15 #include <linux/ip.h> 16 #include <linux/hashtable.h> 17 #include <net/sock.h> 18 #include <net/udp.h> 19 #include <net/af_rxrpc.h> 20 #include "ar-internal.h" 21 22 static void rxrpc_local_processor(struct work_struct *); 23 static void rxrpc_local_rcu(struct rcu_head *); 24 25 /* 26 * Compare a local to an address. Return -ve, 0 or +ve to indicate less than, 27 * same or greater than. 28 * 29 * We explicitly don't compare the RxRPC service ID as we want to reject 30 * conflicting uses by differing services. Further, we don't want to share 31 * addresses with different options (IPv6), so we don't compare those bits 32 * either. 33 */ 34 static long rxrpc_local_cmp_key(const struct rxrpc_local *local, 35 const struct sockaddr_rxrpc *srx) 36 { 37 long diff; 38 39 diff = ((local->srx.transport_type - srx->transport_type) ?: 40 (local->srx.transport_len - srx->transport_len) ?: 41 (local->srx.transport.family - srx->transport.family)); 42 if (diff != 0) 43 return diff; 44 45 switch (srx->transport.family) { 46 case AF_INET: 47 /* If the choice of UDP port is left up to the transport, then 48 * the endpoint record doesn't match. 49 */ 50 return ((u16 __force)local->srx.transport.sin.sin_port - 51 (u16 __force)srx->transport.sin.sin_port) ?: 52 memcmp(&local->srx.transport.sin.sin_addr, 53 &srx->transport.sin.sin_addr, 54 sizeof(struct in_addr)); 55 #ifdef CONFIG_AF_RXRPC_IPV6 56 case AF_INET6: 57 /* If the choice of UDP6 port is left up to the transport, then 58 * the endpoint record doesn't match. 59 */ 60 return ((u16 __force)local->srx.transport.sin6.sin6_port - 61 (u16 __force)srx->transport.sin6.sin6_port) ?: 62 memcmp(&local->srx.transport.sin6.sin6_addr, 63 &srx->transport.sin6.sin6_addr, 64 sizeof(struct in6_addr)); 65 #endif 66 default: 67 BUG(); 68 } 69 } 70 71 /* 72 * Allocate a new local endpoint. 73 */ 74 static struct rxrpc_local *rxrpc_alloc_local(struct rxrpc_net *rxnet, 75 const struct sockaddr_rxrpc *srx) 76 { 77 struct rxrpc_local *local; 78 79 local = kzalloc(sizeof(struct rxrpc_local), GFP_KERNEL); 80 if (local) { 81 atomic_set(&local->usage, 1); 82 atomic_set(&local->active_users, 1); 83 local->rxnet = rxnet; 84 INIT_LIST_HEAD(&local->link); 85 INIT_WORK(&local->processor, rxrpc_local_processor); 86 init_rwsem(&local->defrag_sem); 87 skb_queue_head_init(&local->reject_queue); 88 skb_queue_head_init(&local->event_queue); 89 local->client_conns = RB_ROOT; 90 spin_lock_init(&local->client_conns_lock); 91 spin_lock_init(&local->lock); 92 rwlock_init(&local->services_lock); 93 local->debug_id = atomic_inc_return(&rxrpc_debug_id); 94 memcpy(&local->srx, srx, sizeof(*srx)); 95 local->srx.srx_service = 0; 96 trace_rxrpc_local(local->debug_id, rxrpc_local_new, 1, NULL); 97 } 98 99 _leave(" = %p", local); 100 return local; 101 } 102 103 /* 104 * create the local socket 105 * - must be called with rxrpc_local_mutex locked 106 */ 107 static int rxrpc_open_socket(struct rxrpc_local *local, struct net *net) 108 { 109 struct sock *usk; 110 int ret, opt; 111 112 _enter("%p{%d,%d}", 113 local, local->srx.transport_type, local->srx.transport.family); 114 115 /* create a socket to represent the local endpoint */ 116 ret = sock_create_kern(net, local->srx.transport.family, 117 local->srx.transport_type, 0, &local->socket); 118 if (ret < 0) { 119 _leave(" = %d [socket]", ret); 120 return ret; 121 } 122 123 /* set the socket up */ 124 usk = local->socket->sk; 125 inet_sk(usk)->mc_loop = 0; 126 127 /* Enable CHECKSUM_UNNECESSARY to CHECKSUM_COMPLETE conversion */ 128 inet_inc_convert_csum(usk); 129 130 rcu_assign_sk_user_data(usk, local); 131 132 udp_sk(usk)->encap_type = UDP_ENCAP_RXRPC; 133 udp_sk(usk)->encap_rcv = rxrpc_input_packet; 134 udp_sk(usk)->encap_destroy = NULL; 135 udp_sk(usk)->gro_receive = NULL; 136 udp_sk(usk)->gro_complete = NULL; 137 138 udp_encap_enable(); 139 #if IS_ENABLED(CONFIG_AF_RXRPC_IPV6) 140 if (local->srx.transport.family == AF_INET6) 141 udpv6_encap_enable(); 142 #endif 143 usk->sk_error_report = rxrpc_error_report; 144 145 /* if a local address was supplied then bind it */ 146 if (local->srx.transport_len > sizeof(sa_family_t)) { 147 _debug("bind"); 148 ret = kernel_bind(local->socket, 149 (struct sockaddr *)&local->srx.transport, 150 local->srx.transport_len); 151 if (ret < 0) { 152 _debug("bind failed %d", ret); 153 goto error; 154 } 155 } 156 157 switch (local->srx.transport.family) { 158 case AF_INET6: 159 /* we want to receive ICMPv6 errors */ 160 opt = 1; 161 ret = kernel_setsockopt(local->socket, SOL_IPV6, IPV6_RECVERR, 162 (char *) &opt, sizeof(opt)); 163 if (ret < 0) { 164 _debug("setsockopt failed"); 165 goto error; 166 } 167 168 /* we want to set the don't fragment bit */ 169 opt = IPV6_PMTUDISC_DO; 170 ret = kernel_setsockopt(local->socket, SOL_IPV6, IPV6_MTU_DISCOVER, 171 (char *) &opt, sizeof(opt)); 172 if (ret < 0) { 173 _debug("setsockopt failed"); 174 goto error; 175 } 176 177 /* Fall through and set IPv4 options too otherwise we don't get 178 * errors from IPv4 packets sent through the IPv6 socket. 179 */ 180 /* Fall through */ 181 case AF_INET: 182 /* we want to receive ICMP errors */ 183 opt = 1; 184 ret = kernel_setsockopt(local->socket, SOL_IP, IP_RECVERR, 185 (char *) &opt, sizeof(opt)); 186 if (ret < 0) { 187 _debug("setsockopt failed"); 188 goto error; 189 } 190 191 /* we want to set the don't fragment bit */ 192 opt = IP_PMTUDISC_DO; 193 ret = kernel_setsockopt(local->socket, SOL_IP, IP_MTU_DISCOVER, 194 (char *) &opt, sizeof(opt)); 195 if (ret < 0) { 196 _debug("setsockopt failed"); 197 goto error; 198 } 199 200 /* We want receive timestamps. */ 201 opt = 1; 202 ret = kernel_setsockopt(local->socket, SOL_SOCKET, SO_TIMESTAMPNS_OLD, 203 (char *)&opt, sizeof(opt)); 204 if (ret < 0) { 205 _debug("setsockopt failed"); 206 goto error; 207 } 208 break; 209 210 default: 211 BUG(); 212 } 213 214 _leave(" = 0"); 215 return 0; 216 217 error: 218 kernel_sock_shutdown(local->socket, SHUT_RDWR); 219 local->socket->sk->sk_user_data = NULL; 220 sock_release(local->socket); 221 local->socket = NULL; 222 223 _leave(" = %d", ret); 224 return ret; 225 } 226 227 /* 228 * Look up or create a new local endpoint using the specified local address. 229 */ 230 struct rxrpc_local *rxrpc_lookup_local(struct net *net, 231 const struct sockaddr_rxrpc *srx) 232 { 233 struct rxrpc_local *local; 234 struct rxrpc_net *rxnet = rxrpc_net(net); 235 struct list_head *cursor; 236 const char *age; 237 long diff; 238 int ret; 239 240 _enter("{%d,%d,%pISp}", 241 srx->transport_type, srx->transport.family, &srx->transport); 242 243 mutex_lock(&rxnet->local_mutex); 244 245 for (cursor = rxnet->local_endpoints.next; 246 cursor != &rxnet->local_endpoints; 247 cursor = cursor->next) { 248 local = list_entry(cursor, struct rxrpc_local, link); 249 250 diff = rxrpc_local_cmp_key(local, srx); 251 if (diff < 0) 252 continue; 253 if (diff > 0) 254 break; 255 256 /* Services aren't allowed to share transport sockets, so 257 * reject that here. It is possible that the object is dying - 258 * but it may also still have the local transport address that 259 * we want bound. 260 */ 261 if (srx->srx_service) { 262 local = NULL; 263 goto addr_in_use; 264 } 265 266 /* Found a match. We replace a dying object. Attempting to 267 * bind the transport socket may still fail if we're attempting 268 * to use a local address that the dying object is still using. 269 */ 270 if (!rxrpc_use_local(local)) 271 break; 272 273 age = "old"; 274 goto found; 275 } 276 277 local = rxrpc_alloc_local(rxnet, srx); 278 if (!local) 279 goto nomem; 280 281 ret = rxrpc_open_socket(local, net); 282 if (ret < 0) 283 goto sock_error; 284 285 if (cursor != &rxnet->local_endpoints) 286 list_replace_init(cursor, &local->link); 287 else 288 list_add_tail(&local->link, cursor); 289 age = "new"; 290 291 found: 292 mutex_unlock(&rxnet->local_mutex); 293 294 _net("LOCAL %s %d {%pISp}", 295 age, local->debug_id, &local->srx.transport); 296 297 _leave(" = %p", local); 298 return local; 299 300 nomem: 301 ret = -ENOMEM; 302 sock_error: 303 mutex_unlock(&rxnet->local_mutex); 304 if (local) 305 call_rcu(&local->rcu, rxrpc_local_rcu); 306 _leave(" = %d", ret); 307 return ERR_PTR(ret); 308 309 addr_in_use: 310 mutex_unlock(&rxnet->local_mutex); 311 _leave(" = -EADDRINUSE"); 312 return ERR_PTR(-EADDRINUSE); 313 } 314 315 /* 316 * Get a ref on a local endpoint. 317 */ 318 struct rxrpc_local *rxrpc_get_local(struct rxrpc_local *local) 319 { 320 const void *here = __builtin_return_address(0); 321 int n; 322 323 n = atomic_inc_return(&local->usage); 324 trace_rxrpc_local(local->debug_id, rxrpc_local_got, n, here); 325 return local; 326 } 327 328 /* 329 * Get a ref on a local endpoint unless its usage has already reached 0. 330 */ 331 struct rxrpc_local *rxrpc_get_local_maybe(struct rxrpc_local *local) 332 { 333 const void *here = __builtin_return_address(0); 334 335 if (local) { 336 int n = atomic_fetch_add_unless(&local->usage, 1, 0); 337 if (n > 0) 338 trace_rxrpc_local(local->debug_id, rxrpc_local_got, 339 n + 1, here); 340 else 341 local = NULL; 342 } 343 return local; 344 } 345 346 /* 347 * Queue a local endpoint and pass the caller's reference to the work item. 348 */ 349 void rxrpc_queue_local(struct rxrpc_local *local) 350 { 351 const void *here = __builtin_return_address(0); 352 unsigned int debug_id = local->debug_id; 353 int n = atomic_read(&local->usage); 354 355 if (rxrpc_queue_work(&local->processor)) 356 trace_rxrpc_local(debug_id, rxrpc_local_queued, n, here); 357 else 358 rxrpc_put_local(local); 359 } 360 361 /* 362 * Drop a ref on a local endpoint. 363 */ 364 void rxrpc_put_local(struct rxrpc_local *local) 365 { 366 const void *here = __builtin_return_address(0); 367 int n; 368 369 if (local) { 370 n = atomic_dec_return(&local->usage); 371 trace_rxrpc_local(local->debug_id, rxrpc_local_put, n, here); 372 373 if (n == 0) 374 call_rcu(&local->rcu, rxrpc_local_rcu); 375 } 376 } 377 378 /* 379 * Start using a local endpoint. 380 */ 381 struct rxrpc_local *rxrpc_use_local(struct rxrpc_local *local) 382 { 383 unsigned int au; 384 385 local = rxrpc_get_local_maybe(local); 386 if (!local) 387 return NULL; 388 389 au = atomic_fetch_add_unless(&local->active_users, 1, 0); 390 if (au == 0) { 391 rxrpc_put_local(local); 392 return NULL; 393 } 394 395 return local; 396 } 397 398 /* 399 * Cease using a local endpoint. Once the number of active users reaches 0, we 400 * start the closure of the transport in the work processor. 401 */ 402 void rxrpc_unuse_local(struct rxrpc_local *local) 403 { 404 unsigned int au; 405 406 if (local) { 407 au = atomic_dec_return(&local->active_users); 408 if (au == 0) 409 rxrpc_queue_local(local); 410 else 411 rxrpc_put_local(local); 412 } 413 } 414 415 /* 416 * Destroy a local endpoint's socket and then hand the record to RCU to dispose 417 * of. 418 * 419 * Closing the socket cannot be done from bottom half context or RCU callback 420 * context because it might sleep. 421 */ 422 static void rxrpc_local_destroyer(struct rxrpc_local *local) 423 { 424 struct socket *socket = local->socket; 425 struct rxrpc_net *rxnet = local->rxnet; 426 427 _enter("%d", local->debug_id); 428 429 local->dead = true; 430 431 mutex_lock(&rxnet->local_mutex); 432 list_del_init(&local->link); 433 mutex_unlock(&rxnet->local_mutex); 434 435 rxrpc_clean_up_local_conns(local); 436 rxrpc_service_connection_reaper(&rxnet->service_conn_reaper); 437 ASSERT(!local->service); 438 439 if (socket) { 440 local->socket = NULL; 441 kernel_sock_shutdown(socket, SHUT_RDWR); 442 socket->sk->sk_user_data = NULL; 443 sock_release(socket); 444 } 445 446 /* At this point, there should be no more packets coming in to the 447 * local endpoint. 448 */ 449 rxrpc_purge_queue(&local->reject_queue); 450 rxrpc_purge_queue(&local->event_queue); 451 } 452 453 /* 454 * Process events on an endpoint. The work item carries a ref which 455 * we must release. 456 */ 457 static void rxrpc_local_processor(struct work_struct *work) 458 { 459 struct rxrpc_local *local = 460 container_of(work, struct rxrpc_local, processor); 461 bool again; 462 463 trace_rxrpc_local(local->debug_id, rxrpc_local_processing, 464 atomic_read(&local->usage), NULL); 465 466 do { 467 again = false; 468 if (atomic_read(&local->active_users) == 0) { 469 rxrpc_local_destroyer(local); 470 break; 471 } 472 473 if (!skb_queue_empty(&local->reject_queue)) { 474 rxrpc_reject_packets(local); 475 again = true; 476 } 477 478 if (!skb_queue_empty(&local->event_queue)) { 479 rxrpc_process_local_events(local); 480 again = true; 481 } 482 } while (again); 483 484 rxrpc_put_local(local); 485 } 486 487 /* 488 * Destroy a local endpoint after the RCU grace period expires. 489 */ 490 static void rxrpc_local_rcu(struct rcu_head *rcu) 491 { 492 struct rxrpc_local *local = container_of(rcu, struct rxrpc_local, rcu); 493 494 _enter("%d", local->debug_id); 495 496 ASSERT(!work_pending(&local->processor)); 497 498 _net("DESTROY LOCAL %d", local->debug_id); 499 kfree(local); 500 _leave(""); 501 } 502 503 /* 504 * Verify the local endpoint list is empty by this point. 505 */ 506 void rxrpc_destroy_all_locals(struct rxrpc_net *rxnet) 507 { 508 struct rxrpc_local *local; 509 510 _enter(""); 511 512 flush_workqueue(rxrpc_workqueue); 513 514 if (!list_empty(&rxnet->local_endpoints)) { 515 mutex_lock(&rxnet->local_mutex); 516 list_for_each_entry(local, &rxnet->local_endpoints, link) { 517 pr_err("AF_RXRPC: Leaked local %p {%d}\n", 518 local, atomic_read(&local->usage)); 519 } 520 mutex_unlock(&rxnet->local_mutex); 521 BUG(); 522 } 523 } 524