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 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.sk_user_data = local; 141 setup_udp_tunnel_sock(net, local->socket, &tuncfg); 142 143 /* set the socket up */ 144 usk = local->socket->sk; 145 usk->sk_error_report = rxrpc_error_report; 146 147 switch (srx->transport.family) { 148 case AF_INET6: 149 /* we want to receive ICMPv6 errors */ 150 ip6_sock_set_recverr(usk); 151 152 /* Fall through and set IPv4 options too otherwise we don't get 153 * errors from IPv4 packets sent through the IPv6 socket. 154 */ 155 fallthrough; 156 case AF_INET: 157 /* we want to receive ICMP errors */ 158 ip_sock_set_recverr(usk); 159 160 /* we want to set the don't fragment bit */ 161 ip_sock_set_mtu_discover(usk, IP_PMTUDISC_DO); 162 163 /* We want receive timestamps. */ 164 sock_enable_timestamps(usk); 165 break; 166 167 default: 168 BUG(); 169 } 170 171 _leave(" = 0"); 172 return 0; 173 } 174 175 /* 176 * Look up or create a new local endpoint using the specified local address. 177 */ 178 struct rxrpc_local *rxrpc_lookup_local(struct net *net, 179 const struct sockaddr_rxrpc *srx) 180 { 181 struct rxrpc_local *local; 182 struct rxrpc_net *rxnet = rxrpc_net(net); 183 struct list_head *cursor; 184 const char *age; 185 long diff; 186 int ret; 187 188 _enter("{%d,%d,%pISp}", 189 srx->transport_type, srx->transport.family, &srx->transport); 190 191 mutex_lock(&rxnet->local_mutex); 192 193 for (cursor = rxnet->local_endpoints.next; 194 cursor != &rxnet->local_endpoints; 195 cursor = cursor->next) { 196 local = list_entry(cursor, struct rxrpc_local, link); 197 198 diff = rxrpc_local_cmp_key(local, srx); 199 if (diff < 0) 200 continue; 201 if (diff > 0) 202 break; 203 204 /* Services aren't allowed to share transport sockets, so 205 * reject that here. It is possible that the object is dying - 206 * but it may also still have the local transport address that 207 * we want bound. 208 */ 209 if (srx->srx_service) { 210 local = NULL; 211 goto addr_in_use; 212 } 213 214 /* Found a match. We replace a dying object. Attempting to 215 * bind the transport socket may still fail if we're attempting 216 * to use a local address that the dying object is still using. 217 */ 218 if (!rxrpc_use_local(local)) 219 break; 220 221 age = "old"; 222 goto found; 223 } 224 225 local = rxrpc_alloc_local(rxnet, srx); 226 if (!local) 227 goto nomem; 228 229 ret = rxrpc_open_socket(local, net); 230 if (ret < 0) 231 goto sock_error; 232 233 if (cursor != &rxnet->local_endpoints) 234 list_replace_init(cursor, &local->link); 235 else 236 list_add_tail(&local->link, cursor); 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 n; 270 271 n = atomic_inc_return(&local->usage); 272 trace_rxrpc_local(local->debug_id, rxrpc_local_got, n, 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); 282 283 if (local) { 284 int n = atomic_fetch_add_unless(&local->usage, 1, 0); 285 if (n > 0) 286 trace_rxrpc_local(local->debug_id, rxrpc_local_got, 287 n + 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 n = atomic_read(&local->usage); 302 303 if (rxrpc_queue_work(&local->processor)) 304 trace_rxrpc_local(debug_id, rxrpc_local_queued, n, 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 int n; 317 318 if (local) { 319 debug_id = local->debug_id; 320 321 n = atomic_dec_return(&local->usage); 322 trace_rxrpc_local(debug_id, rxrpc_local_put, n, here); 323 324 if (n == 0) 325 call_rcu(&local->rcu, rxrpc_local_rcu); 326 } 327 } 328 329 /* 330 * Start using a local endpoint. 331 */ 332 struct rxrpc_local *rxrpc_use_local(struct rxrpc_local *local) 333 { 334 local = rxrpc_get_local_maybe(local); 335 if (!local) 336 return NULL; 337 338 if (!__rxrpc_use_local(local)) { 339 rxrpc_put_local(local); 340 return NULL; 341 } 342 343 return local; 344 } 345 346 /* 347 * Cease using a local endpoint. Once the number of active users reaches 0, we 348 * start the closure of the transport in the work processor. 349 */ 350 void rxrpc_unuse_local(struct rxrpc_local *local) 351 { 352 if (local) { 353 if (__rxrpc_unuse_local(local)) { 354 rxrpc_get_local(local); 355 rxrpc_queue_local(local); 356 } 357 } 358 } 359 360 /* 361 * Destroy a local endpoint's socket and then hand the record to RCU to dispose 362 * of. 363 * 364 * Closing the socket cannot be done from bottom half context or RCU callback 365 * context because it might sleep. 366 */ 367 static void rxrpc_local_destroyer(struct rxrpc_local *local) 368 { 369 struct socket *socket = local->socket; 370 struct rxrpc_net *rxnet = local->rxnet; 371 372 _enter("%d", local->debug_id); 373 374 local->dead = true; 375 376 mutex_lock(&rxnet->local_mutex); 377 list_del_init(&local->link); 378 mutex_unlock(&rxnet->local_mutex); 379 380 rxrpc_clean_up_local_conns(local); 381 rxrpc_service_connection_reaper(&rxnet->service_conn_reaper); 382 ASSERT(!local->service); 383 384 if (socket) { 385 local->socket = NULL; 386 kernel_sock_shutdown(socket, SHUT_RDWR); 387 socket->sk->sk_user_data = NULL; 388 sock_release(socket); 389 } 390 391 /* At this point, there should be no more packets coming in to the 392 * local endpoint. 393 */ 394 rxrpc_purge_queue(&local->reject_queue); 395 rxrpc_purge_queue(&local->event_queue); 396 } 397 398 /* 399 * Process events on an endpoint. The work item carries a ref which 400 * we must release. 401 */ 402 static void rxrpc_local_processor(struct work_struct *work) 403 { 404 struct rxrpc_local *local = 405 container_of(work, struct rxrpc_local, processor); 406 bool again; 407 408 trace_rxrpc_local(local->debug_id, rxrpc_local_processing, 409 atomic_read(&local->usage), NULL); 410 411 do { 412 again = false; 413 if (!__rxrpc_use_local(local)) { 414 rxrpc_local_destroyer(local); 415 break; 416 } 417 418 if (!skb_queue_empty(&local->reject_queue)) { 419 rxrpc_reject_packets(local); 420 again = true; 421 } 422 423 if (!skb_queue_empty(&local->event_queue)) { 424 rxrpc_process_local_events(local); 425 again = true; 426 } 427 428 __rxrpc_unuse_local(local); 429 } while (again); 430 431 rxrpc_put_local(local); 432 } 433 434 /* 435 * Destroy a local endpoint after the RCU grace period expires. 436 */ 437 static void rxrpc_local_rcu(struct rcu_head *rcu) 438 { 439 struct rxrpc_local *local = container_of(rcu, struct rxrpc_local, rcu); 440 441 _enter("%d", local->debug_id); 442 443 ASSERT(!work_pending(&local->processor)); 444 445 _net("DESTROY LOCAL %d", local->debug_id); 446 kfree(local); 447 _leave(""); 448 } 449 450 /* 451 * Verify the local endpoint list is empty by this point. 452 */ 453 void rxrpc_destroy_all_locals(struct rxrpc_net *rxnet) 454 { 455 struct rxrpc_local *local; 456 457 _enter(""); 458 459 flush_workqueue(rxrpc_workqueue); 460 461 if (!list_empty(&rxnet->local_endpoints)) { 462 mutex_lock(&rxnet->local_mutex); 463 list_for_each_entry(local, &rxnet->local_endpoints, link) { 464 pr_err("AF_RXRPC: Leaked local %p {%d}\n", 465 local, atomic_read(&local->usage)); 466 } 467 mutex_unlock(&rxnet->local_mutex); 468 BUG(); 469 } 470 } 471