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/udp_tunnel.h> 20 #include <net/af_rxrpc.h> 21 #include "ar-internal.h" 22 23 static void rxrpc_local_processor(struct work_struct *); 24 static void rxrpc_local_rcu(struct rcu_head *); 25 26 /* 27 * Compare a local to an address. Return -ve, 0 or +ve to indicate less than, 28 * same or greater than. 29 * 30 * We explicitly don't compare the RxRPC service ID as we want to reject 31 * conflicting uses by differing services. Further, we don't want to share 32 * addresses with different options (IPv6), so we don't compare those bits 33 * either. 34 */ 35 static long rxrpc_local_cmp_key(const struct rxrpc_local *local, 36 const struct sockaddr_rxrpc *srx) 37 { 38 long diff; 39 40 diff = ((local->srx.transport_type - srx->transport_type) ?: 41 (local->srx.transport_len - srx->transport_len) ?: 42 (local->srx.transport.family - srx->transport.family)); 43 if (diff != 0) 44 return diff; 45 46 switch (srx->transport.family) { 47 case AF_INET: 48 /* If the choice of UDP port is left up to the transport, then 49 * the endpoint record doesn't match. 50 */ 51 return ((u16 __force)local->srx.transport.sin.sin_port - 52 (u16 __force)srx->transport.sin.sin_port) ?: 53 memcmp(&local->srx.transport.sin.sin_addr, 54 &srx->transport.sin.sin_addr, 55 sizeof(struct in_addr)); 56 #ifdef CONFIG_AF_RXRPC_IPV6 57 case AF_INET6: 58 /* If the choice of UDP6 port is left up to the transport, then 59 * the endpoint record doesn't match. 60 */ 61 return ((u16 __force)local->srx.transport.sin6.sin6_port - 62 (u16 __force)srx->transport.sin6.sin6_port) ?: 63 memcmp(&local->srx.transport.sin6.sin6_addr, 64 &srx->transport.sin6.sin6_addr, 65 sizeof(struct in6_addr)); 66 #endif 67 default: 68 BUG(); 69 } 70 } 71 72 /* 73 * Allocate a new local endpoint. 74 */ 75 static struct rxrpc_local *rxrpc_alloc_local(struct rxrpc_net *rxnet, 76 const struct sockaddr_rxrpc *srx) 77 { 78 struct rxrpc_local *local; 79 80 local = kzalloc(sizeof(struct rxrpc_local), GFP_KERNEL); 81 if (local) { 82 refcount_set(&local->ref, 1); 83 atomic_set(&local->active_users, 1); 84 local->rxnet = rxnet; 85 INIT_HLIST_NODE(&local->link); 86 INIT_WORK(&local->processor, rxrpc_local_processor); 87 init_rwsem(&local->defrag_sem); 88 skb_queue_head_init(&local->reject_queue); 89 skb_queue_head_init(&local->event_queue); 90 local->client_bundles = RB_ROOT; 91 spin_lock_init(&local->client_bundles_lock); 92 spin_lock_init(&local->lock); 93 rwlock_init(&local->services_lock); 94 local->debug_id = atomic_inc_return(&rxrpc_debug_id); 95 memcpy(&local->srx, srx, sizeof(*srx)); 96 local->srx.srx_service = 0; 97 trace_rxrpc_local(local->debug_id, rxrpc_local_new, 1, NULL); 98 } 99 100 _leave(" = %p", local); 101 return local; 102 } 103 104 /* 105 * create the local socket 106 * - must be called with rxrpc_local_mutex locked 107 */ 108 static int rxrpc_open_socket(struct rxrpc_local *local, struct net *net) 109 { 110 struct udp_tunnel_sock_cfg tuncfg = {NULL}; 111 struct sockaddr_rxrpc *srx = &local->srx; 112 struct udp_port_cfg udp_conf = {0}; 113 struct sock *usk; 114 int ret; 115 116 _enter("%p{%d,%d}", 117 local, srx->transport_type, srx->transport.family); 118 119 udp_conf.family = srx->transport.family; 120 udp_conf.use_udp_checksums = true; 121 if (udp_conf.family == AF_INET) { 122 udp_conf.local_ip = srx->transport.sin.sin_addr; 123 udp_conf.local_udp_port = srx->transport.sin.sin_port; 124 #if IS_ENABLED(CONFIG_AF_RXRPC_IPV6) 125 } else { 126 udp_conf.local_ip6 = srx->transport.sin6.sin6_addr; 127 udp_conf.local_udp_port = srx->transport.sin6.sin6_port; 128 udp_conf.use_udp6_tx_checksums = true; 129 udp_conf.use_udp6_rx_checksums = true; 130 #endif 131 } 132 ret = udp_sock_create(net, &udp_conf, &local->socket); 133 if (ret < 0) { 134 _leave(" = %d [socket]", ret); 135 return ret; 136 } 137 138 tuncfg.encap_type = UDP_ENCAP_RXRPC; 139 tuncfg.encap_rcv = rxrpc_input_packet; 140 tuncfg.encap_err_rcv = rxrpc_encap_err_rcv; 141 tuncfg.sk_user_data = local; 142 setup_udp_tunnel_sock(net, local->socket, &tuncfg); 143 144 /* set the socket up */ 145 usk = local->socket->sk; 146 usk->sk_error_report = rxrpc_error_report; 147 148 switch (srx->transport.family) { 149 case AF_INET6: 150 /* we want to receive ICMPv6 errors */ 151 ip6_sock_set_recverr(usk); 152 153 /* Fall through and set IPv4 options too otherwise we don't get 154 * errors from IPv4 packets sent through the IPv6 socket. 155 */ 156 fallthrough; 157 case AF_INET: 158 /* we want to receive ICMP errors */ 159 ip_sock_set_recverr(usk); 160 161 /* we want to set the don't fragment bit */ 162 ip_sock_set_mtu_discover(usk, IP_PMTUDISC_DO); 163 164 /* We want receive timestamps. */ 165 sock_enable_timestamps(usk); 166 break; 167 168 default: 169 BUG(); 170 } 171 172 _leave(" = 0"); 173 return 0; 174 } 175 176 /* 177 * Look up or create a new local endpoint using the specified local address. 178 */ 179 struct rxrpc_local *rxrpc_lookup_local(struct net *net, 180 const struct sockaddr_rxrpc *srx) 181 { 182 struct rxrpc_local *local; 183 struct rxrpc_net *rxnet = rxrpc_net(net); 184 struct hlist_node *cursor; 185 const char *age; 186 long diff; 187 int ret; 188 189 _enter("{%d,%d,%pISp}", 190 srx->transport_type, srx->transport.family, &srx->transport); 191 192 mutex_lock(&rxnet->local_mutex); 193 194 hlist_for_each(cursor, &rxnet->local_endpoints) { 195 local = hlist_entry(cursor, struct rxrpc_local, link); 196 197 diff = rxrpc_local_cmp_key(local, srx); 198 if (diff != 0) 199 continue; 200 201 /* Services aren't allowed to share transport sockets, so 202 * reject that here. It is possible that the object is dying - 203 * but it may also still have the local transport address that 204 * we want bound. 205 */ 206 if (srx->srx_service) { 207 local = NULL; 208 goto addr_in_use; 209 } 210 211 /* Found a match. We want to replace a dying object. 212 * Attempting to bind the transport socket may still fail if 213 * we're attempting to use a local address that the dying 214 * object is still using. 215 */ 216 if (!rxrpc_use_local(local)) 217 break; 218 219 age = "old"; 220 goto found; 221 } 222 223 local = rxrpc_alloc_local(rxnet, srx); 224 if (!local) 225 goto nomem; 226 227 ret = rxrpc_open_socket(local, net); 228 if (ret < 0) 229 goto sock_error; 230 231 if (cursor) { 232 hlist_replace_rcu(cursor, &local->link); 233 cursor->pprev = NULL; 234 } else { 235 hlist_add_head_rcu(&local->link, &rxnet->local_endpoints); 236 } 237 age = "new"; 238 239 found: 240 mutex_unlock(&rxnet->local_mutex); 241 242 _net("LOCAL %s %d {%pISp}", 243 age, local->debug_id, &local->srx.transport); 244 245 _leave(" = %p", local); 246 return local; 247 248 nomem: 249 ret = -ENOMEM; 250 sock_error: 251 mutex_unlock(&rxnet->local_mutex); 252 if (local) 253 call_rcu(&local->rcu, rxrpc_local_rcu); 254 _leave(" = %d", ret); 255 return ERR_PTR(ret); 256 257 addr_in_use: 258 mutex_unlock(&rxnet->local_mutex); 259 _leave(" = -EADDRINUSE"); 260 return ERR_PTR(-EADDRINUSE); 261 } 262 263 /* 264 * Get a ref on a local endpoint. 265 */ 266 struct rxrpc_local *rxrpc_get_local(struct rxrpc_local *local) 267 { 268 const void *here = __builtin_return_address(0); 269 int r; 270 271 __refcount_inc(&local->ref, &r); 272 trace_rxrpc_local(local->debug_id, rxrpc_local_got, r + 1, here); 273 return local; 274 } 275 276 /* 277 * Get a ref on a local endpoint unless its usage has already reached 0. 278 */ 279 struct rxrpc_local *rxrpc_get_local_maybe(struct rxrpc_local *local) 280 { 281 const void *here = __builtin_return_address(0); 282 int r; 283 284 if (local) { 285 if (__refcount_inc_not_zero(&local->ref, &r)) 286 trace_rxrpc_local(local->debug_id, rxrpc_local_got, 287 r + 1, here); 288 else 289 local = NULL; 290 } 291 return local; 292 } 293 294 /* 295 * Queue a local endpoint and pass the caller's reference to the work item. 296 */ 297 void rxrpc_queue_local(struct rxrpc_local *local) 298 { 299 const void *here = __builtin_return_address(0); 300 unsigned int debug_id = local->debug_id; 301 int r = refcount_read(&local->ref); 302 303 if (rxrpc_queue_work(&local->processor)) 304 trace_rxrpc_local(debug_id, rxrpc_local_queued, r + 1, here); 305 else 306 rxrpc_put_local(local); 307 } 308 309 /* 310 * Drop a ref on a local endpoint. 311 */ 312 void rxrpc_put_local(struct rxrpc_local *local) 313 { 314 const void *here = __builtin_return_address(0); 315 unsigned int debug_id; 316 bool dead; 317 int r; 318 319 if (local) { 320 debug_id = local->debug_id; 321 322 dead = __refcount_dec_and_test(&local->ref, &r); 323 trace_rxrpc_local(debug_id, rxrpc_local_put, r, here); 324 325 if (dead) 326 call_rcu(&local->rcu, rxrpc_local_rcu); 327 } 328 } 329 330 /* 331 * Start using a local endpoint. 332 */ 333 struct rxrpc_local *rxrpc_use_local(struct rxrpc_local *local) 334 { 335 local = rxrpc_get_local_maybe(local); 336 if (!local) 337 return NULL; 338 339 if (!__rxrpc_use_local(local)) { 340 rxrpc_put_local(local); 341 return NULL; 342 } 343 344 return local; 345 } 346 347 /* 348 * Cease using a local endpoint. Once the number of active users reaches 0, we 349 * start the closure of the transport in the work processor. 350 */ 351 void rxrpc_unuse_local(struct rxrpc_local *local) 352 { 353 if (local) { 354 if (__rxrpc_unuse_local(local)) { 355 rxrpc_get_local(local); 356 rxrpc_queue_local(local); 357 } 358 } 359 } 360 361 /* 362 * Destroy a local endpoint's socket and then hand the record to RCU to dispose 363 * of. 364 * 365 * Closing the socket cannot be done from bottom half context or RCU callback 366 * context because it might sleep. 367 */ 368 static void rxrpc_local_destroyer(struct rxrpc_local *local) 369 { 370 struct socket *socket = local->socket; 371 struct rxrpc_net *rxnet = local->rxnet; 372 373 _enter("%d", local->debug_id); 374 375 local->dead = true; 376 377 mutex_lock(&rxnet->local_mutex); 378 hlist_del_init_rcu(&local->link); 379 mutex_unlock(&rxnet->local_mutex); 380 381 rxrpc_clean_up_local_conns(local); 382 rxrpc_service_connection_reaper(&rxnet->service_conn_reaper); 383 ASSERT(!local->service); 384 385 if (socket) { 386 local->socket = NULL; 387 kernel_sock_shutdown(socket, SHUT_RDWR); 388 socket->sk->sk_user_data = NULL; 389 sock_release(socket); 390 } 391 392 /* At this point, there should be no more packets coming in to the 393 * local endpoint. 394 */ 395 rxrpc_purge_queue(&local->reject_queue); 396 rxrpc_purge_queue(&local->event_queue); 397 } 398 399 /* 400 * Process events on an endpoint. The work item carries a ref which 401 * we must release. 402 */ 403 static void rxrpc_local_processor(struct work_struct *work) 404 { 405 struct rxrpc_local *local = 406 container_of(work, struct rxrpc_local, processor); 407 bool again; 408 409 if (local->dead) 410 return; 411 412 trace_rxrpc_local(local->debug_id, rxrpc_local_processing, 413 refcount_read(&local->ref), NULL); 414 415 do { 416 again = false; 417 if (!__rxrpc_use_local(local)) { 418 rxrpc_local_destroyer(local); 419 break; 420 } 421 422 if (!skb_queue_empty(&local->reject_queue)) { 423 rxrpc_reject_packets(local); 424 again = true; 425 } 426 427 if (!skb_queue_empty(&local->event_queue)) { 428 rxrpc_process_local_events(local); 429 again = true; 430 } 431 432 __rxrpc_unuse_local(local); 433 } while (again); 434 435 rxrpc_put_local(local); 436 } 437 438 /* 439 * Destroy a local endpoint after the RCU grace period expires. 440 */ 441 static void rxrpc_local_rcu(struct rcu_head *rcu) 442 { 443 struct rxrpc_local *local = container_of(rcu, struct rxrpc_local, rcu); 444 445 _enter("%d", local->debug_id); 446 447 ASSERT(!work_pending(&local->processor)); 448 449 _net("DESTROY LOCAL %d", local->debug_id); 450 kfree(local); 451 _leave(""); 452 } 453 454 /* 455 * Verify the local endpoint list is empty by this point. 456 */ 457 void rxrpc_destroy_all_locals(struct rxrpc_net *rxnet) 458 { 459 struct rxrpc_local *local; 460 461 _enter(""); 462 463 flush_workqueue(rxrpc_workqueue); 464 465 if (!hlist_empty(&rxnet->local_endpoints)) { 466 mutex_lock(&rxnet->local_mutex); 467 hlist_for_each_entry(local, &rxnet->local_endpoints, link) { 468 pr_err("AF_RXRPC: Leaked local %p {%d}\n", 469 local, refcount_read(&local->ref)); 470 } 471 mutex_unlock(&rxnet->local_mutex); 472 BUG(); 473 } 474 } 475