1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* RxRPC remote transport endpoint record management 3 * 4 * Copyright (C) 2007, 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/udp.h> 14 #include <linux/in.h> 15 #include <linux/in6.h> 16 #include <linux/slab.h> 17 #include <linux/hashtable.h> 18 #include <net/sock.h> 19 #include <net/af_rxrpc.h> 20 #include <net/ip.h> 21 #include <net/route.h> 22 #include <net/ip6_route.h> 23 #include "ar-internal.h" 24 25 static const struct sockaddr_rxrpc rxrpc_null_addr; 26 27 /* 28 * Hash a peer key. 29 */ 30 static unsigned long rxrpc_peer_hash_key(struct rxrpc_local *local, 31 const struct sockaddr_rxrpc *srx) 32 { 33 const u16 *p; 34 unsigned int i, size; 35 unsigned long hash_key; 36 37 _enter(""); 38 39 hash_key = (unsigned long)local / __alignof__(*local); 40 hash_key += srx->transport_type; 41 hash_key += srx->transport_len; 42 hash_key += srx->transport.family; 43 44 switch (srx->transport.family) { 45 case AF_INET: 46 hash_key += (u16 __force)srx->transport.sin.sin_port; 47 size = sizeof(srx->transport.sin.sin_addr); 48 p = (u16 *)&srx->transport.sin.sin_addr; 49 break; 50 #ifdef CONFIG_AF_RXRPC_IPV6 51 case AF_INET6: 52 hash_key += (u16 __force)srx->transport.sin.sin_port; 53 size = sizeof(srx->transport.sin6.sin6_addr); 54 p = (u16 *)&srx->transport.sin6.sin6_addr; 55 break; 56 #endif 57 default: 58 WARN(1, "AF_RXRPC: Unsupported transport address family\n"); 59 return 0; 60 } 61 62 /* Step through the peer address in 16-bit portions for speed */ 63 for (i = 0; i < size; i += sizeof(*p), p++) 64 hash_key += *p; 65 66 _leave(" 0x%lx", hash_key); 67 return hash_key; 68 } 69 70 /* 71 * Compare a peer to a key. Return -ve, 0 or +ve to indicate less than, same 72 * or greater than. 73 * 74 * Unfortunately, the primitives in linux/hashtable.h don't allow for sorted 75 * buckets and mid-bucket insertion, so we don't make full use of this 76 * information at this point. 77 */ 78 static long rxrpc_peer_cmp_key(const struct rxrpc_peer *peer, 79 struct rxrpc_local *local, 80 const struct sockaddr_rxrpc *srx, 81 unsigned long hash_key) 82 { 83 long diff; 84 85 diff = ((peer->hash_key - hash_key) ?: 86 ((unsigned long)peer->local - (unsigned long)local) ?: 87 (peer->srx.transport_type - srx->transport_type) ?: 88 (peer->srx.transport_len - srx->transport_len) ?: 89 (peer->srx.transport.family - srx->transport.family)); 90 if (diff != 0) 91 return diff; 92 93 switch (srx->transport.family) { 94 case AF_INET: 95 return ((u16 __force)peer->srx.transport.sin.sin_port - 96 (u16 __force)srx->transport.sin.sin_port) ?: 97 memcmp(&peer->srx.transport.sin.sin_addr, 98 &srx->transport.sin.sin_addr, 99 sizeof(struct in_addr)); 100 #ifdef CONFIG_AF_RXRPC_IPV6 101 case AF_INET6: 102 return ((u16 __force)peer->srx.transport.sin6.sin6_port - 103 (u16 __force)srx->transport.sin6.sin6_port) ?: 104 memcmp(&peer->srx.transport.sin6.sin6_addr, 105 &srx->transport.sin6.sin6_addr, 106 sizeof(struct in6_addr)); 107 #endif 108 default: 109 BUG(); 110 } 111 } 112 113 /* 114 * Look up a remote transport endpoint for the specified address using RCU. 115 */ 116 static struct rxrpc_peer *__rxrpc_lookup_peer_rcu( 117 struct rxrpc_local *local, 118 const struct sockaddr_rxrpc *srx, 119 unsigned long hash_key) 120 { 121 struct rxrpc_peer *peer; 122 struct rxrpc_net *rxnet = local->rxnet; 123 124 hash_for_each_possible_rcu(rxnet->peer_hash, peer, hash_link, hash_key) { 125 if (rxrpc_peer_cmp_key(peer, local, srx, hash_key) == 0 && 126 refcount_read(&peer->ref) > 0) 127 return peer; 128 } 129 130 return NULL; 131 } 132 133 /* 134 * Look up a remote transport endpoint for the specified address using RCU. 135 */ 136 struct rxrpc_peer *rxrpc_lookup_peer_rcu(struct rxrpc_local *local, 137 const struct sockaddr_rxrpc *srx) 138 { 139 struct rxrpc_peer *peer; 140 unsigned long hash_key = rxrpc_peer_hash_key(local, srx); 141 142 peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key); 143 if (peer) 144 _leave(" = %p {u=%d}", peer, refcount_read(&peer->ref)); 145 return peer; 146 } 147 148 /* 149 * assess the MTU size for the network interface through which this peer is 150 * reached 151 */ 152 static void rxrpc_assess_MTU_size(struct rxrpc_local *local, 153 struct rxrpc_peer *peer) 154 { 155 struct net *net = local->net; 156 struct dst_entry *dst; 157 struct rtable *rt; 158 struct flowi fl; 159 struct flowi4 *fl4 = &fl.u.ip4; 160 #ifdef CONFIG_AF_RXRPC_IPV6 161 struct flowi6 *fl6 = &fl.u.ip6; 162 #endif 163 164 peer->if_mtu = 1500; 165 166 memset(&fl, 0, sizeof(fl)); 167 switch (peer->srx.transport.family) { 168 case AF_INET: 169 rt = ip_route_output_ports( 170 net, fl4, NULL, 171 peer->srx.transport.sin.sin_addr.s_addr, 0, 172 htons(7000), htons(7001), IPPROTO_UDP, 0, 0); 173 if (IS_ERR(rt)) { 174 _leave(" [route err %ld]", PTR_ERR(rt)); 175 return; 176 } 177 dst = &rt->dst; 178 break; 179 180 #ifdef CONFIG_AF_RXRPC_IPV6 181 case AF_INET6: 182 fl6->flowi6_iif = LOOPBACK_IFINDEX; 183 fl6->flowi6_scope = RT_SCOPE_UNIVERSE; 184 fl6->flowi6_proto = IPPROTO_UDP; 185 memcpy(&fl6->daddr, &peer->srx.transport.sin6.sin6_addr, 186 sizeof(struct in6_addr)); 187 fl6->fl6_dport = htons(7001); 188 fl6->fl6_sport = htons(7000); 189 dst = ip6_route_output(net, NULL, fl6); 190 if (dst->error) { 191 _leave(" [route err %d]", dst->error); 192 return; 193 } 194 break; 195 #endif 196 197 default: 198 BUG(); 199 } 200 201 peer->if_mtu = dst_mtu(dst); 202 dst_release(dst); 203 204 _leave(" [if_mtu %u]", peer->if_mtu); 205 } 206 207 /* 208 * Allocate a peer. 209 */ 210 struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *local, gfp_t gfp, 211 enum rxrpc_peer_trace why) 212 { 213 struct rxrpc_peer *peer; 214 215 _enter(""); 216 217 peer = kzalloc(sizeof(struct rxrpc_peer), gfp); 218 if (peer) { 219 refcount_set(&peer->ref, 1); 220 peer->local = rxrpc_get_local(local, rxrpc_local_get_peer); 221 INIT_HLIST_HEAD(&peer->error_targets); 222 peer->service_conns = RB_ROOT; 223 seqlock_init(&peer->service_conn_lock); 224 spin_lock_init(&peer->lock); 225 spin_lock_init(&peer->rtt_input_lock); 226 peer->debug_id = atomic_inc_return(&rxrpc_debug_id); 227 228 rxrpc_peer_init_rtt(peer); 229 230 peer->cong_ssthresh = RXRPC_TX_MAX_WINDOW; 231 trace_rxrpc_peer(peer->debug_id, 1, why); 232 } 233 234 _leave(" = %p", peer); 235 return peer; 236 } 237 238 /* 239 * Initialise peer record. 240 */ 241 static void rxrpc_init_peer(struct rxrpc_local *local, struct rxrpc_peer *peer, 242 unsigned long hash_key) 243 { 244 peer->hash_key = hash_key; 245 rxrpc_assess_MTU_size(local, peer); 246 peer->mtu = peer->if_mtu; 247 peer->rtt_last_req = ktime_get_real(); 248 249 switch (peer->srx.transport.family) { 250 case AF_INET: 251 peer->hdrsize = sizeof(struct iphdr); 252 break; 253 #ifdef CONFIG_AF_RXRPC_IPV6 254 case AF_INET6: 255 peer->hdrsize = sizeof(struct ipv6hdr); 256 break; 257 #endif 258 default: 259 BUG(); 260 } 261 262 switch (peer->srx.transport_type) { 263 case SOCK_DGRAM: 264 peer->hdrsize += sizeof(struct udphdr); 265 break; 266 default: 267 BUG(); 268 } 269 270 peer->hdrsize += sizeof(struct rxrpc_wire_header); 271 peer->maxdata = peer->mtu - peer->hdrsize; 272 } 273 274 /* 275 * Set up a new peer. 276 */ 277 static struct rxrpc_peer *rxrpc_create_peer(struct rxrpc_local *local, 278 struct sockaddr_rxrpc *srx, 279 unsigned long hash_key, 280 gfp_t gfp) 281 { 282 struct rxrpc_peer *peer; 283 284 _enter(""); 285 286 peer = rxrpc_alloc_peer(local, gfp, rxrpc_peer_new_client); 287 if (peer) { 288 memcpy(&peer->srx, srx, sizeof(*srx)); 289 rxrpc_init_peer(local, peer, hash_key); 290 } 291 292 _leave(" = %p", peer); 293 return peer; 294 } 295 296 static void rxrpc_free_peer(struct rxrpc_peer *peer) 297 { 298 trace_rxrpc_peer(peer->debug_id, 0, rxrpc_peer_free); 299 rxrpc_put_local(peer->local, rxrpc_local_put_peer); 300 kfree_rcu(peer, rcu); 301 } 302 303 /* 304 * Set up a new incoming peer. There shouldn't be any other matching peers 305 * since we've already done a search in the list from the non-reentrant context 306 * (the data_ready handler) that is the only place we can add new peers. 307 */ 308 void rxrpc_new_incoming_peer(struct rxrpc_local *local, struct rxrpc_peer *peer) 309 { 310 struct rxrpc_net *rxnet = local->rxnet; 311 unsigned long hash_key; 312 313 hash_key = rxrpc_peer_hash_key(local, &peer->srx); 314 rxrpc_init_peer(local, peer, hash_key); 315 316 spin_lock(&rxnet->peer_hash_lock); 317 hash_add_rcu(rxnet->peer_hash, &peer->hash_link, hash_key); 318 list_add_tail(&peer->keepalive_link, &rxnet->peer_keepalive_new); 319 spin_unlock(&rxnet->peer_hash_lock); 320 } 321 322 /* 323 * obtain a remote transport endpoint for the specified address 324 */ 325 struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_local *local, 326 struct sockaddr_rxrpc *srx, gfp_t gfp) 327 { 328 struct rxrpc_peer *peer, *candidate; 329 struct rxrpc_net *rxnet = local->rxnet; 330 unsigned long hash_key = rxrpc_peer_hash_key(local, srx); 331 332 _enter("{%pISp}", &srx->transport); 333 334 /* search the peer list first */ 335 rcu_read_lock(); 336 peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key); 337 if (peer && !rxrpc_get_peer_maybe(peer, rxrpc_peer_get_lookup_client)) 338 peer = NULL; 339 rcu_read_unlock(); 340 341 if (!peer) { 342 /* The peer is not yet present in hash - create a candidate 343 * for a new record and then redo the search. 344 */ 345 candidate = rxrpc_create_peer(local, srx, hash_key, gfp); 346 if (!candidate) { 347 _leave(" = NULL [nomem]"); 348 return NULL; 349 } 350 351 spin_lock(&rxnet->peer_hash_lock); 352 353 /* Need to check that we aren't racing with someone else */ 354 peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key); 355 if (peer && !rxrpc_get_peer_maybe(peer, rxrpc_peer_get_lookup_client)) 356 peer = NULL; 357 if (!peer) { 358 hash_add_rcu(rxnet->peer_hash, 359 &candidate->hash_link, hash_key); 360 list_add_tail(&candidate->keepalive_link, 361 &rxnet->peer_keepalive_new); 362 } 363 364 spin_unlock(&rxnet->peer_hash_lock); 365 366 if (peer) 367 rxrpc_free_peer(candidate); 368 else 369 peer = candidate; 370 } 371 372 _leave(" = %p {u=%d}", peer, refcount_read(&peer->ref)); 373 return peer; 374 } 375 376 /* 377 * Get a ref on a peer record. 378 */ 379 struct rxrpc_peer *rxrpc_get_peer(struct rxrpc_peer *peer, enum rxrpc_peer_trace why) 380 { 381 int r; 382 383 __refcount_inc(&peer->ref, &r); 384 trace_rxrpc_peer(peer->debug_id, r + 1, why); 385 return peer; 386 } 387 388 /* 389 * Get a ref on a peer record unless its usage has already reached 0. 390 */ 391 struct rxrpc_peer *rxrpc_get_peer_maybe(struct rxrpc_peer *peer, 392 enum rxrpc_peer_trace why) 393 { 394 int r; 395 396 if (peer) { 397 if (__refcount_inc_not_zero(&peer->ref, &r)) 398 trace_rxrpc_peer(peer->debug_id, r + 1, why); 399 else 400 peer = NULL; 401 } 402 return peer; 403 } 404 405 /* 406 * Discard a peer record. 407 */ 408 static void __rxrpc_put_peer(struct rxrpc_peer *peer) 409 { 410 struct rxrpc_net *rxnet = peer->local->rxnet; 411 412 ASSERT(hlist_empty(&peer->error_targets)); 413 414 spin_lock(&rxnet->peer_hash_lock); 415 hash_del_rcu(&peer->hash_link); 416 list_del_init(&peer->keepalive_link); 417 spin_unlock(&rxnet->peer_hash_lock); 418 419 rxrpc_free_peer(peer); 420 } 421 422 /* 423 * Drop a ref on a peer record. 424 */ 425 void rxrpc_put_peer(struct rxrpc_peer *peer, enum rxrpc_peer_trace why) 426 { 427 unsigned int debug_id; 428 bool dead; 429 int r; 430 431 if (peer) { 432 debug_id = peer->debug_id; 433 dead = __refcount_dec_and_test(&peer->ref, &r); 434 trace_rxrpc_peer(debug_id, r - 1, why); 435 if (dead) 436 __rxrpc_put_peer(peer); 437 } 438 } 439 440 /* 441 * Make sure all peer records have been discarded. 442 */ 443 void rxrpc_destroy_all_peers(struct rxrpc_net *rxnet) 444 { 445 struct rxrpc_peer *peer; 446 int i; 447 448 for (i = 0; i < HASH_SIZE(rxnet->peer_hash); i++) { 449 if (hlist_empty(&rxnet->peer_hash[i])) 450 continue; 451 452 hlist_for_each_entry(peer, &rxnet->peer_hash[i], hash_link) { 453 pr_err("Leaked peer %u {%u} %pISp\n", 454 peer->debug_id, 455 refcount_read(&peer->ref), 456 &peer->srx.transport); 457 } 458 } 459 } 460 461 /** 462 * rxrpc_kernel_get_call_peer - Get the peer address of a call 463 * @sock: The socket on which the call is in progress. 464 * @call: The call to query 465 * 466 * Get a record for the remote peer in a call. 467 */ 468 struct rxrpc_peer *rxrpc_kernel_get_call_peer(struct socket *sock, struct rxrpc_call *call) 469 { 470 return call->peer; 471 } 472 EXPORT_SYMBOL(rxrpc_kernel_get_call_peer); 473 474 /** 475 * rxrpc_kernel_get_srtt - Get a call's peer smoothed RTT 476 * @peer: The peer to query 477 * 478 * Get the call's peer smoothed RTT in uS or UINT_MAX if we have no samples. 479 */ 480 unsigned int rxrpc_kernel_get_srtt(const struct rxrpc_peer *peer) 481 { 482 return peer->rtt_count > 0 ? peer->srtt_us >> 3 : UINT_MAX; 483 } 484 EXPORT_SYMBOL(rxrpc_kernel_get_srtt); 485 486 /** 487 * rxrpc_kernel_remote_srx - Get the address of a peer 488 * @peer: The peer to query 489 * 490 * Get a pointer to the address from a peer record. The caller is responsible 491 * for making sure that the address is not deallocated. 492 */ 493 const struct sockaddr_rxrpc *rxrpc_kernel_remote_srx(const struct rxrpc_peer *peer) 494 { 495 return peer ? &peer->srx : &rxrpc_null_addr; 496 } 497 EXPORT_SYMBOL(rxrpc_kernel_remote_srx); 498 499 /** 500 * rxrpc_kernel_remote_addr - Get the peer transport address of a call 501 * @peer: The peer to query 502 * 503 * Get a pointer to the transport address from a peer record. The caller is 504 * responsible for making sure that the address is not deallocated. 505 */ 506 const struct sockaddr *rxrpc_kernel_remote_addr(const struct rxrpc_peer *peer) 507 { 508 return (const struct sockaddr *) 509 (peer ? &peer->srx.transport : &rxrpc_null_addr.transport); 510 } 511 EXPORT_SYMBOL(rxrpc_kernel_remote_addr); 512