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 atomic_set(&local->usage, 1); 83 atomic_set(&local->active_users, 1); 84 local->rxnet = rxnet; 85 INIT_LIST_HEAD(&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 if (udp_conf.family == AF_INET) { 121 udp_conf.local_ip = srx->transport.sin.sin_addr; 122 udp_conf.local_udp_port = srx->transport.sin.sin_port; 123 #if IS_ENABLED(CONFIG_AF_RXRPC_IPV6) 124 } else { 125 udp_conf.local_ip6 = srx->transport.sin6.sin6_addr; 126 udp_conf.local_udp_port = srx->transport.sin6.sin6_port; 127 #endif 128 } 129 ret = udp_sock_create(net, &udp_conf, &local->socket); 130 if (ret < 0) { 131 _leave(" = %d [socket]", ret); 132 return ret; 133 } 134 135 tuncfg.encap_type = UDP_ENCAP_RXRPC; 136 tuncfg.encap_rcv = rxrpc_input_packet; 137 tuncfg.sk_user_data = local; 138 setup_udp_tunnel_sock(net, local->socket, &tuncfg); 139 140 /* set the socket up */ 141 usk = local->socket->sk; 142 usk->sk_error_report = rxrpc_error_report; 143 144 switch (srx->transport.family) { 145 case AF_INET6: 146 /* we want to receive ICMPv6 errors */ 147 ip6_sock_set_recverr(usk); 148 149 /* Fall through and set IPv4 options too otherwise we don't get 150 * errors from IPv4 packets sent through the IPv6 socket. 151 */ 152 fallthrough; 153 case AF_INET: 154 /* we want to receive ICMP errors */ 155 ip_sock_set_recverr(usk); 156 157 /* we want to set the don't fragment bit */ 158 ip_sock_set_mtu_discover(usk, IP_PMTUDISC_DO); 159 160 /* We want receive timestamps. */ 161 sock_enable_timestamps(usk); 162 break; 163 164 default: 165 BUG(); 166 } 167 168 _leave(" = 0"); 169 return 0; 170 } 171 172 /* 173 * Look up or create a new local endpoint using the specified local address. 174 */ 175 struct rxrpc_local *rxrpc_lookup_local(struct net *net, 176 const struct sockaddr_rxrpc *srx) 177 { 178 struct rxrpc_local *local; 179 struct rxrpc_net *rxnet = rxrpc_net(net); 180 struct list_head *cursor; 181 const char *age; 182 long diff; 183 int ret; 184 185 _enter("{%d,%d,%pISp}", 186 srx->transport_type, srx->transport.family, &srx->transport); 187 188 mutex_lock(&rxnet->local_mutex); 189 190 for (cursor = rxnet->local_endpoints.next; 191 cursor != &rxnet->local_endpoints; 192 cursor = cursor->next) { 193 local = list_entry(cursor, struct rxrpc_local, link); 194 195 diff = rxrpc_local_cmp_key(local, srx); 196 if (diff < 0) 197 continue; 198 if (diff > 0) 199 break; 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 replace a dying object. Attempting to 212 * bind the transport socket may still fail if we're attempting 213 * to use a local address that the dying object is still using. 214 */ 215 if (!rxrpc_use_local(local)) 216 break; 217 218 age = "old"; 219 goto found; 220 } 221 222 local = rxrpc_alloc_local(rxnet, srx); 223 if (!local) 224 goto nomem; 225 226 ret = rxrpc_open_socket(local, net); 227 if (ret < 0) 228 goto sock_error; 229 230 if (cursor != &rxnet->local_endpoints) 231 list_replace_init(cursor, &local->link); 232 else 233 list_add_tail(&local->link, cursor); 234 age = "new"; 235 236 found: 237 mutex_unlock(&rxnet->local_mutex); 238 239 _net("LOCAL %s %d {%pISp}", 240 age, local->debug_id, &local->srx.transport); 241 242 _leave(" = %p", local); 243 return local; 244 245 nomem: 246 ret = -ENOMEM; 247 sock_error: 248 mutex_unlock(&rxnet->local_mutex); 249 if (local) 250 call_rcu(&local->rcu, rxrpc_local_rcu); 251 _leave(" = %d", ret); 252 return ERR_PTR(ret); 253 254 addr_in_use: 255 mutex_unlock(&rxnet->local_mutex); 256 _leave(" = -EADDRINUSE"); 257 return ERR_PTR(-EADDRINUSE); 258 } 259 260 /* 261 * Get a ref on a local endpoint. 262 */ 263 struct rxrpc_local *rxrpc_get_local(struct rxrpc_local *local) 264 { 265 const void *here = __builtin_return_address(0); 266 int n; 267 268 n = atomic_inc_return(&local->usage); 269 trace_rxrpc_local(local->debug_id, rxrpc_local_got, n, here); 270 return local; 271 } 272 273 /* 274 * Get a ref on a local endpoint unless its usage has already reached 0. 275 */ 276 struct rxrpc_local *rxrpc_get_local_maybe(struct rxrpc_local *local) 277 { 278 const void *here = __builtin_return_address(0); 279 280 if (local) { 281 int n = atomic_fetch_add_unless(&local->usage, 1, 0); 282 if (n > 0) 283 trace_rxrpc_local(local->debug_id, rxrpc_local_got, 284 n + 1, here); 285 else 286 local = NULL; 287 } 288 return local; 289 } 290 291 /* 292 * Queue a local endpoint and pass the caller's reference to the work item. 293 */ 294 void rxrpc_queue_local(struct rxrpc_local *local) 295 { 296 const void *here = __builtin_return_address(0); 297 unsigned int debug_id = local->debug_id; 298 int n = atomic_read(&local->usage); 299 300 if (rxrpc_queue_work(&local->processor)) 301 trace_rxrpc_local(debug_id, rxrpc_local_queued, n, here); 302 else 303 rxrpc_put_local(local); 304 } 305 306 /* 307 * Drop a ref on a local endpoint. 308 */ 309 void rxrpc_put_local(struct rxrpc_local *local) 310 { 311 const void *here = __builtin_return_address(0); 312 unsigned int debug_id; 313 int n; 314 315 if (local) { 316 debug_id = local->debug_id; 317 318 n = atomic_dec_return(&local->usage); 319 trace_rxrpc_local(debug_id, rxrpc_local_put, n, here); 320 321 if (n == 0) 322 call_rcu(&local->rcu, rxrpc_local_rcu); 323 } 324 } 325 326 /* 327 * Start using a local endpoint. 328 */ 329 struct rxrpc_local *rxrpc_use_local(struct rxrpc_local *local) 330 { 331 local = rxrpc_get_local_maybe(local); 332 if (!local) 333 return NULL; 334 335 if (!__rxrpc_use_local(local)) { 336 rxrpc_put_local(local); 337 return NULL; 338 } 339 340 return local; 341 } 342 343 /* 344 * Cease using a local endpoint. Once the number of active users reaches 0, we 345 * start the closure of the transport in the work processor. 346 */ 347 void rxrpc_unuse_local(struct rxrpc_local *local) 348 { 349 if (local) { 350 if (__rxrpc_unuse_local(local)) { 351 rxrpc_get_local(local); 352 rxrpc_queue_local(local); 353 } 354 } 355 } 356 357 /* 358 * Destroy a local endpoint's socket and then hand the record to RCU to dispose 359 * of. 360 * 361 * Closing the socket cannot be done from bottom half context or RCU callback 362 * context because it might sleep. 363 */ 364 static void rxrpc_local_destroyer(struct rxrpc_local *local) 365 { 366 struct socket *socket = local->socket; 367 struct rxrpc_net *rxnet = local->rxnet; 368 369 _enter("%d", local->debug_id); 370 371 local->dead = true; 372 373 mutex_lock(&rxnet->local_mutex); 374 list_del_init(&local->link); 375 mutex_unlock(&rxnet->local_mutex); 376 377 rxrpc_clean_up_local_conns(local); 378 rxrpc_service_connection_reaper(&rxnet->service_conn_reaper); 379 ASSERT(!local->service); 380 381 if (socket) { 382 local->socket = NULL; 383 kernel_sock_shutdown(socket, SHUT_RDWR); 384 socket->sk->sk_user_data = NULL; 385 sock_release(socket); 386 } 387 388 /* At this point, there should be no more packets coming in to the 389 * local endpoint. 390 */ 391 rxrpc_purge_queue(&local->reject_queue); 392 rxrpc_purge_queue(&local->event_queue); 393 } 394 395 /* 396 * Process events on an endpoint. The work item carries a ref which 397 * we must release. 398 */ 399 static void rxrpc_local_processor(struct work_struct *work) 400 { 401 struct rxrpc_local *local = 402 container_of(work, struct rxrpc_local, processor); 403 bool again; 404 405 trace_rxrpc_local(local->debug_id, rxrpc_local_processing, 406 atomic_read(&local->usage), NULL); 407 408 do { 409 again = false; 410 if (!__rxrpc_use_local(local)) { 411 rxrpc_local_destroyer(local); 412 break; 413 } 414 415 if (!skb_queue_empty(&local->reject_queue)) { 416 rxrpc_reject_packets(local); 417 again = true; 418 } 419 420 if (!skb_queue_empty(&local->event_queue)) { 421 rxrpc_process_local_events(local); 422 again = true; 423 } 424 425 __rxrpc_unuse_local(local); 426 } while (again); 427 428 rxrpc_put_local(local); 429 } 430 431 /* 432 * Destroy a local endpoint after the RCU grace period expires. 433 */ 434 static void rxrpc_local_rcu(struct rcu_head *rcu) 435 { 436 struct rxrpc_local *local = container_of(rcu, struct rxrpc_local, rcu); 437 438 _enter("%d", local->debug_id); 439 440 ASSERT(!work_pending(&local->processor)); 441 442 _net("DESTROY LOCAL %d", local->debug_id); 443 kfree(local); 444 _leave(""); 445 } 446 447 /* 448 * Verify the local endpoint list is empty by this point. 449 */ 450 void rxrpc_destroy_all_locals(struct rxrpc_net *rxnet) 451 { 452 struct rxrpc_local *local; 453 454 _enter(""); 455 456 flush_workqueue(rxrpc_workqueue); 457 458 if (!list_empty(&rxnet->local_endpoints)) { 459 mutex_lock(&rxnet->local_mutex); 460 list_for_each_entry(local, &rxnet->local_endpoints, link) { 461 pr_err("AF_RXRPC: Leaked local %p {%d}\n", 462 local, atomic_read(&local->usage)); 463 } 464 mutex_unlock(&rxnet->local_mutex); 465 BUG(); 466 } 467 } 468