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 /* Fall through and set IPv4 options too otherwise we don't get 169 * errors from IPv4 packets sent through the IPv6 socket. 170 */ 171 /* Fall through */ 172 case AF_INET: 173 /* we want to receive ICMP errors */ 174 opt = 1; 175 ret = kernel_setsockopt(local->socket, SOL_IP, IP_RECVERR, 176 (char *) &opt, sizeof(opt)); 177 if (ret < 0) { 178 _debug("setsockopt failed"); 179 goto error; 180 } 181 182 /* we want to set the don't fragment bit */ 183 opt = IP_PMTUDISC_DO; 184 ret = kernel_setsockopt(local->socket, SOL_IP, IP_MTU_DISCOVER, 185 (char *) &opt, sizeof(opt)); 186 if (ret < 0) { 187 _debug("setsockopt failed"); 188 goto error; 189 } 190 191 /* We want receive timestamps. */ 192 opt = 1; 193 ret = kernel_setsockopt(local->socket, SOL_SOCKET, SO_TIMESTAMPNS_OLD, 194 (char *)&opt, sizeof(opt)); 195 if (ret < 0) { 196 _debug("setsockopt failed"); 197 goto error; 198 } 199 break; 200 201 default: 202 BUG(); 203 } 204 205 _leave(" = 0"); 206 return 0; 207 208 error: 209 kernel_sock_shutdown(local->socket, SHUT_RDWR); 210 local->socket->sk->sk_user_data = NULL; 211 sock_release(local->socket); 212 local->socket = NULL; 213 214 _leave(" = %d", ret); 215 return ret; 216 } 217 218 /* 219 * Look up or create a new local endpoint using the specified local address. 220 */ 221 struct rxrpc_local *rxrpc_lookup_local(struct net *net, 222 const struct sockaddr_rxrpc *srx) 223 { 224 struct rxrpc_local *local; 225 struct rxrpc_net *rxnet = rxrpc_net(net); 226 struct list_head *cursor; 227 const char *age; 228 long diff; 229 int ret; 230 231 _enter("{%d,%d,%pISp}", 232 srx->transport_type, srx->transport.family, &srx->transport); 233 234 mutex_lock(&rxnet->local_mutex); 235 236 for (cursor = rxnet->local_endpoints.next; 237 cursor != &rxnet->local_endpoints; 238 cursor = cursor->next) { 239 local = list_entry(cursor, struct rxrpc_local, link); 240 241 diff = rxrpc_local_cmp_key(local, srx); 242 if (diff < 0) 243 continue; 244 if (diff > 0) 245 break; 246 247 /* Services aren't allowed to share transport sockets, so 248 * reject that here. It is possible that the object is dying - 249 * but it may also still have the local transport address that 250 * we want bound. 251 */ 252 if (srx->srx_service) { 253 local = NULL; 254 goto addr_in_use; 255 } 256 257 /* Found a match. We replace a dying object. Attempting to 258 * bind the transport socket may still fail if we're attempting 259 * to use a local address that the dying object is still using. 260 */ 261 if (!rxrpc_use_local(local)) 262 break; 263 264 age = "old"; 265 goto found; 266 } 267 268 local = rxrpc_alloc_local(rxnet, srx); 269 if (!local) 270 goto nomem; 271 272 ret = rxrpc_open_socket(local, net); 273 if (ret < 0) 274 goto sock_error; 275 276 if (cursor != &rxnet->local_endpoints) 277 list_replace_init(cursor, &local->link); 278 else 279 list_add_tail(&local->link, cursor); 280 age = "new"; 281 282 found: 283 mutex_unlock(&rxnet->local_mutex); 284 285 _net("LOCAL %s %d {%pISp}", 286 age, local->debug_id, &local->srx.transport); 287 288 _leave(" = %p", local); 289 return local; 290 291 nomem: 292 ret = -ENOMEM; 293 sock_error: 294 mutex_unlock(&rxnet->local_mutex); 295 if (local) 296 call_rcu(&local->rcu, rxrpc_local_rcu); 297 _leave(" = %d", ret); 298 return ERR_PTR(ret); 299 300 addr_in_use: 301 mutex_unlock(&rxnet->local_mutex); 302 _leave(" = -EADDRINUSE"); 303 return ERR_PTR(-EADDRINUSE); 304 } 305 306 /* 307 * Get a ref on a local endpoint. 308 */ 309 struct rxrpc_local *rxrpc_get_local(struct rxrpc_local *local) 310 { 311 const void *here = __builtin_return_address(0); 312 int n; 313 314 n = atomic_inc_return(&local->usage); 315 trace_rxrpc_local(local->debug_id, rxrpc_local_got, n, here); 316 return local; 317 } 318 319 /* 320 * Get a ref on a local endpoint unless its usage has already reached 0. 321 */ 322 struct rxrpc_local *rxrpc_get_local_maybe(struct rxrpc_local *local) 323 { 324 const void *here = __builtin_return_address(0); 325 326 if (local) { 327 int n = atomic_fetch_add_unless(&local->usage, 1, 0); 328 if (n > 0) 329 trace_rxrpc_local(local->debug_id, rxrpc_local_got, 330 n + 1, here); 331 else 332 local = NULL; 333 } 334 return local; 335 } 336 337 /* 338 * Queue a local endpoint and pass the caller's reference to the work item. 339 */ 340 void rxrpc_queue_local(struct rxrpc_local *local) 341 { 342 const void *here = __builtin_return_address(0); 343 unsigned int debug_id = local->debug_id; 344 int n = atomic_read(&local->usage); 345 346 if (rxrpc_queue_work(&local->processor)) 347 trace_rxrpc_local(debug_id, rxrpc_local_queued, n, here); 348 else 349 rxrpc_put_local(local); 350 } 351 352 /* 353 * Drop a ref on a local endpoint. 354 */ 355 void rxrpc_put_local(struct rxrpc_local *local) 356 { 357 const void *here = __builtin_return_address(0); 358 unsigned int debug_id; 359 int n; 360 361 if (local) { 362 debug_id = local->debug_id; 363 364 n = atomic_dec_return(&local->usage); 365 trace_rxrpc_local(debug_id, rxrpc_local_put, n, here); 366 367 if (n == 0) 368 call_rcu(&local->rcu, rxrpc_local_rcu); 369 } 370 } 371 372 /* 373 * Start using a local endpoint. 374 */ 375 struct rxrpc_local *rxrpc_use_local(struct rxrpc_local *local) 376 { 377 local = rxrpc_get_local_maybe(local); 378 if (!local) 379 return NULL; 380 381 if (!__rxrpc_use_local(local)) { 382 rxrpc_put_local(local); 383 return NULL; 384 } 385 386 return local; 387 } 388 389 /* 390 * Cease using a local endpoint. Once the number of active users reaches 0, we 391 * start the closure of the transport in the work processor. 392 */ 393 void rxrpc_unuse_local(struct rxrpc_local *local) 394 { 395 if (local) { 396 if (__rxrpc_unuse_local(local)) { 397 rxrpc_get_local(local); 398 rxrpc_queue_local(local); 399 } 400 } 401 } 402 403 /* 404 * Destroy a local endpoint's socket and then hand the record to RCU to dispose 405 * of. 406 * 407 * Closing the socket cannot be done from bottom half context or RCU callback 408 * context because it might sleep. 409 */ 410 static void rxrpc_local_destroyer(struct rxrpc_local *local) 411 { 412 struct socket *socket = local->socket; 413 struct rxrpc_net *rxnet = local->rxnet; 414 415 _enter("%d", local->debug_id); 416 417 local->dead = true; 418 419 mutex_lock(&rxnet->local_mutex); 420 list_del_init(&local->link); 421 mutex_unlock(&rxnet->local_mutex); 422 423 rxrpc_clean_up_local_conns(local); 424 rxrpc_service_connection_reaper(&rxnet->service_conn_reaper); 425 ASSERT(!local->service); 426 427 if (socket) { 428 local->socket = NULL; 429 kernel_sock_shutdown(socket, SHUT_RDWR); 430 socket->sk->sk_user_data = NULL; 431 sock_release(socket); 432 } 433 434 /* At this point, there should be no more packets coming in to the 435 * local endpoint. 436 */ 437 rxrpc_purge_queue(&local->reject_queue); 438 rxrpc_purge_queue(&local->event_queue); 439 } 440 441 /* 442 * Process events on an endpoint. The work item carries a ref which 443 * we must release. 444 */ 445 static void rxrpc_local_processor(struct work_struct *work) 446 { 447 struct rxrpc_local *local = 448 container_of(work, struct rxrpc_local, processor); 449 bool again; 450 451 trace_rxrpc_local(local->debug_id, rxrpc_local_processing, 452 atomic_read(&local->usage), NULL); 453 454 do { 455 again = false; 456 if (!__rxrpc_use_local(local)) { 457 rxrpc_local_destroyer(local); 458 break; 459 } 460 461 if (!skb_queue_empty(&local->reject_queue)) { 462 rxrpc_reject_packets(local); 463 again = true; 464 } 465 466 if (!skb_queue_empty(&local->event_queue)) { 467 rxrpc_process_local_events(local); 468 again = true; 469 } 470 471 __rxrpc_unuse_local(local); 472 } while (again); 473 474 rxrpc_put_local(local); 475 } 476 477 /* 478 * Destroy a local endpoint after the RCU grace period expires. 479 */ 480 static void rxrpc_local_rcu(struct rcu_head *rcu) 481 { 482 struct rxrpc_local *local = container_of(rcu, struct rxrpc_local, rcu); 483 484 _enter("%d", local->debug_id); 485 486 ASSERT(!work_pending(&local->processor)); 487 488 _net("DESTROY LOCAL %d", local->debug_id); 489 kfree(local); 490 _leave(""); 491 } 492 493 /* 494 * Verify the local endpoint list is empty by this point. 495 */ 496 void rxrpc_destroy_all_locals(struct rxrpc_net *rxnet) 497 { 498 struct rxrpc_local *local; 499 500 _enter(""); 501 502 flush_workqueue(rxrpc_workqueue); 503 504 if (!list_empty(&rxnet->local_endpoints)) { 505 mutex_lock(&rxnet->local_mutex); 506 list_for_each_entry(local, &rxnet->local_endpoints, link) { 507 pr_err("AF_RXRPC: Leaked local %p {%d}\n", 508 local, atomic_read(&local->usage)); 509 } 510 mutex_unlock(&rxnet->local_mutex); 511 BUG(); 512 } 513 } 514