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 void rxrpc_assess_MTU_size(struct rxrpc_local *local, struct rxrpc_peer *peer) 153 { 154 struct net *net = local->net; 155 struct dst_entry *dst; 156 struct rtable *rt; 157 struct flowi fl; 158 struct flowi4 *fl4 = &fl.u.ip4; 159 #ifdef CONFIG_AF_RXRPC_IPV6 160 struct flowi6 *fl6 = &fl.u.ip6; 161 #endif 162 163 peer->if_mtu = 1500; 164 if (peer->max_data < peer->if_mtu - peer->hdrsize) { 165 trace_rxrpc_pmtud_reduce(peer, 0, peer->if_mtu - peer->hdrsize, 166 rxrpc_pmtud_reduce_route); 167 peer->max_data = peer->if_mtu - peer->hdrsize; 168 } 169 170 memset(&fl, 0, sizeof(fl)); 171 switch (peer->srx.transport.family) { 172 case AF_INET: 173 rt = ip_route_output_ports( 174 net, fl4, NULL, 175 peer->srx.transport.sin.sin_addr.s_addr, 0, 176 htons(7000), htons(7001), IPPROTO_UDP, 0, 0); 177 if (IS_ERR(rt)) { 178 _leave(" [route err %ld]", PTR_ERR(rt)); 179 return; 180 } 181 dst = &rt->dst; 182 break; 183 184 #ifdef CONFIG_AF_RXRPC_IPV6 185 case AF_INET6: 186 fl6->flowi6_iif = LOOPBACK_IFINDEX; 187 fl6->flowi6_scope = RT_SCOPE_UNIVERSE; 188 fl6->flowi6_proto = IPPROTO_UDP; 189 memcpy(&fl6->daddr, &peer->srx.transport.sin6.sin6_addr, 190 sizeof(struct in6_addr)); 191 fl6->fl6_dport = htons(7001); 192 fl6->fl6_sport = htons(7000); 193 dst = ip6_route_output(net, NULL, fl6); 194 if (dst->error) { 195 _leave(" [route err %d]", dst->error); 196 return; 197 } 198 break; 199 #endif 200 201 default: 202 BUG(); 203 } 204 205 peer->if_mtu = dst_mtu(dst); 206 peer->hdrsize += dst->header_len + dst->trailer_len; 207 peer->tx_seg_max = dst->dev->gso_max_segs; 208 dst_release(dst); 209 210 peer->max_data = umin(RXRPC_JUMBO(1), peer->if_mtu - peer->hdrsize); 211 peer->pmtud_good = 500; 212 peer->pmtud_bad = peer->if_mtu - peer->hdrsize + 1; 213 peer->pmtud_trial = umin(peer->max_data, peer->pmtud_bad - 1); 214 peer->pmtud_pending = true; 215 216 _leave(" [if_mtu %u]", peer->if_mtu); 217 } 218 219 /* 220 * Allocate a peer. 221 */ 222 struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *local, gfp_t gfp, 223 enum rxrpc_peer_trace why) 224 { 225 struct rxrpc_peer *peer; 226 227 _enter(""); 228 229 peer = kzalloc(sizeof(struct rxrpc_peer), gfp); 230 if (peer) { 231 refcount_set(&peer->ref, 1); 232 peer->local = rxrpc_get_local(local, rxrpc_local_get_peer); 233 INIT_HLIST_HEAD(&peer->error_targets); 234 peer->service_conns = RB_ROOT; 235 seqlock_init(&peer->service_conn_lock); 236 spin_lock_init(&peer->lock); 237 peer->debug_id = atomic_inc_return(&rxrpc_debug_id); 238 peer->recent_srtt_us = UINT_MAX; 239 peer->cong_ssthresh = RXRPC_TX_MAX_WINDOW; 240 trace_rxrpc_peer(peer->debug_id, 1, why); 241 } 242 243 _leave(" = %p", peer); 244 return peer; 245 } 246 247 /* 248 * Initialise peer record. 249 */ 250 static void rxrpc_init_peer(struct rxrpc_local *local, struct rxrpc_peer *peer, 251 unsigned long hash_key) 252 { 253 peer->hash_key = hash_key; 254 255 256 switch (peer->srx.transport.family) { 257 case AF_INET: 258 peer->hdrsize = sizeof(struct iphdr); 259 break; 260 #ifdef CONFIG_AF_RXRPC_IPV6 261 case AF_INET6: 262 peer->hdrsize = sizeof(struct ipv6hdr); 263 break; 264 #endif 265 default: 266 BUG(); 267 } 268 269 switch (peer->srx.transport_type) { 270 case SOCK_DGRAM: 271 peer->hdrsize += sizeof(struct udphdr); 272 break; 273 default: 274 BUG(); 275 } 276 277 peer->hdrsize += sizeof(struct rxrpc_wire_header); 278 peer->max_data = peer->if_mtu - peer->hdrsize; 279 } 280 281 /* 282 * Set up a new peer. 283 */ 284 static struct rxrpc_peer *rxrpc_create_peer(struct rxrpc_local *local, 285 struct sockaddr_rxrpc *srx, 286 unsigned long hash_key, 287 gfp_t gfp) 288 { 289 struct rxrpc_peer *peer; 290 291 _enter(""); 292 293 peer = rxrpc_alloc_peer(local, gfp, rxrpc_peer_new_client); 294 if (peer) { 295 memcpy(&peer->srx, srx, sizeof(*srx)); 296 rxrpc_init_peer(local, peer, hash_key); 297 rxrpc_assess_MTU_size(local, peer); 298 } 299 300 _leave(" = %p", peer); 301 return peer; 302 } 303 304 static void rxrpc_free_peer(struct rxrpc_peer *peer) 305 { 306 trace_rxrpc_peer(peer->debug_id, 0, rxrpc_peer_free); 307 rxrpc_put_local(peer->local, rxrpc_local_put_peer); 308 kfree_rcu(peer, rcu); 309 } 310 311 /* 312 * Set up a new incoming peer. There shouldn't be any other matching peers 313 * since we've already done a search in the list from the non-reentrant context 314 * (the data_ready handler) that is the only place we can add new peers. 315 * Called with interrupts disabled. 316 */ 317 void rxrpc_new_incoming_peer(struct rxrpc_local *local, struct rxrpc_peer *peer) 318 { 319 struct rxrpc_net *rxnet = local->rxnet; 320 unsigned long hash_key; 321 322 hash_key = rxrpc_peer_hash_key(local, &peer->srx); 323 rxrpc_init_peer(local, peer, hash_key); 324 325 spin_lock(&rxnet->peer_hash_lock); 326 hash_add_rcu(rxnet->peer_hash, &peer->hash_link, hash_key); 327 list_add_tail(&peer->keepalive_link, &rxnet->peer_keepalive_new); 328 spin_unlock(&rxnet->peer_hash_lock); 329 } 330 331 /* 332 * obtain a remote transport endpoint for the specified address 333 */ 334 struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_local *local, 335 struct sockaddr_rxrpc *srx, gfp_t gfp) 336 { 337 struct rxrpc_peer *peer, *candidate; 338 struct rxrpc_net *rxnet = local->rxnet; 339 unsigned long hash_key = rxrpc_peer_hash_key(local, srx); 340 341 _enter("{%pISp}", &srx->transport); 342 343 /* search the peer list first */ 344 rcu_read_lock(); 345 peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key); 346 if (peer && !rxrpc_get_peer_maybe(peer, rxrpc_peer_get_lookup_client)) 347 peer = NULL; 348 rcu_read_unlock(); 349 350 if (!peer) { 351 /* The peer is not yet present in hash - create a candidate 352 * for a new record and then redo the search. 353 */ 354 candidate = rxrpc_create_peer(local, srx, hash_key, gfp); 355 if (!candidate) { 356 _leave(" = NULL [nomem]"); 357 return NULL; 358 } 359 360 spin_lock_bh(&rxnet->peer_hash_lock); 361 362 /* Need to check that we aren't racing with someone else */ 363 peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key); 364 if (peer && !rxrpc_get_peer_maybe(peer, rxrpc_peer_get_lookup_client)) 365 peer = NULL; 366 if (!peer) { 367 hash_add_rcu(rxnet->peer_hash, 368 &candidate->hash_link, hash_key); 369 list_add_tail(&candidate->keepalive_link, 370 &rxnet->peer_keepalive_new); 371 } 372 373 spin_unlock_bh(&rxnet->peer_hash_lock); 374 375 if (peer) 376 rxrpc_free_peer(candidate); 377 else 378 peer = candidate; 379 } 380 381 _leave(" = %p {u=%d}", peer, refcount_read(&peer->ref)); 382 return peer; 383 } 384 385 /* 386 * Get a ref on a peer record. 387 */ 388 struct rxrpc_peer *rxrpc_get_peer(struct rxrpc_peer *peer, enum rxrpc_peer_trace why) 389 { 390 int r; 391 392 __refcount_inc(&peer->ref, &r); 393 trace_rxrpc_peer(peer->debug_id, r + 1, why); 394 return peer; 395 } 396 397 /* 398 * Get a ref on a peer record unless its usage has already reached 0. 399 */ 400 struct rxrpc_peer *rxrpc_get_peer_maybe(struct rxrpc_peer *peer, 401 enum rxrpc_peer_trace why) 402 { 403 int r; 404 405 if (peer) { 406 if (__refcount_inc_not_zero(&peer->ref, &r)) 407 trace_rxrpc_peer(peer->debug_id, r + 1, why); 408 else 409 peer = NULL; 410 } 411 return peer; 412 } 413 414 /* 415 * Discard a peer record. 416 */ 417 static void __rxrpc_put_peer(struct rxrpc_peer *peer) 418 { 419 struct rxrpc_net *rxnet = peer->local->rxnet; 420 421 ASSERT(hlist_empty(&peer->error_targets)); 422 423 spin_lock_bh(&rxnet->peer_hash_lock); 424 hash_del_rcu(&peer->hash_link); 425 list_del_init(&peer->keepalive_link); 426 spin_unlock_bh(&rxnet->peer_hash_lock); 427 428 rxrpc_free_peer(peer); 429 } 430 431 /* 432 * Drop a ref on a peer record. 433 */ 434 void rxrpc_put_peer(struct rxrpc_peer *peer, enum rxrpc_peer_trace why) 435 { 436 unsigned int debug_id; 437 bool dead; 438 int r; 439 440 if (peer) { 441 debug_id = peer->debug_id; 442 dead = __refcount_dec_and_test(&peer->ref, &r); 443 trace_rxrpc_peer(debug_id, r - 1, why); 444 if (dead) 445 __rxrpc_put_peer(peer); 446 } 447 } 448 449 /* 450 * Make sure all peer records have been discarded. 451 */ 452 void rxrpc_destroy_all_peers(struct rxrpc_net *rxnet) 453 { 454 struct rxrpc_peer *peer; 455 int i; 456 457 for (i = 0; i < HASH_SIZE(rxnet->peer_hash); i++) { 458 if (hlist_empty(&rxnet->peer_hash[i])) 459 continue; 460 461 hlist_for_each_entry(peer, &rxnet->peer_hash[i], hash_link) { 462 pr_err("Leaked peer %x {%u} %pISp\n", 463 peer->debug_id, 464 refcount_read(&peer->ref), 465 &peer->srx.transport); 466 } 467 } 468 } 469 470 /** 471 * rxrpc_kernel_get_call_peer - Get the peer address of a call 472 * @sock: The socket on which the call is in progress. 473 * @call: The call to query 474 * 475 * Get a record for the remote peer in a call. 476 * 477 * Return: The call's peer record. 478 */ 479 struct rxrpc_peer *rxrpc_kernel_get_call_peer(struct socket *sock, struct rxrpc_call *call) 480 { 481 return rxrpc_get_peer(call->peer, rxrpc_peer_get_application); 482 } 483 EXPORT_SYMBOL(rxrpc_kernel_get_call_peer); 484 485 /** 486 * rxrpc_kernel_get_srtt - Get a call's peer smoothed RTT 487 * @peer: The peer to query 488 * 489 * Get the call's peer smoothed RTT. 490 * 491 * Return: The RTT in uS or %UINT_MAX if we have no samples. 492 */ 493 unsigned int rxrpc_kernel_get_srtt(const struct rxrpc_peer *peer) 494 { 495 return READ_ONCE(peer->recent_srtt_us); 496 } 497 EXPORT_SYMBOL(rxrpc_kernel_get_srtt); 498 499 /** 500 * rxrpc_kernel_remote_srx - Get the address of a peer 501 * @peer: The peer to query 502 * 503 * Get a pointer to the address from a peer record. The caller is responsible 504 * for making sure that the address is not deallocated. A fake address will be 505 * substituted if %peer in NULL. 506 * 507 * Return: The rxrpc address record or a fake record. 508 */ 509 const struct sockaddr_rxrpc *rxrpc_kernel_remote_srx(const struct rxrpc_peer *peer) 510 { 511 return peer ? &peer->srx : &rxrpc_null_addr; 512 } 513 EXPORT_SYMBOL(rxrpc_kernel_remote_srx); 514 515 /** 516 * rxrpc_kernel_remote_addr - Get the peer transport address of a call 517 * @peer: The peer to query 518 * 519 * Get a pointer to the transport address from a peer record. The caller is 520 * responsible for making sure that the address is not deallocated. A fake 521 * address will be substituted if %peer in NULL. 522 * 523 * Return: The transport address record or a fake record. 524 */ 525 const struct sockaddr *rxrpc_kernel_remote_addr(const struct rxrpc_peer *peer) 526 { 527 return (const struct sockaddr *) 528 (peer ? &peer->srx.transport : &rxrpc_null_addr.transport); 529 } 530 EXPORT_SYMBOL(rxrpc_kernel_remote_addr); 531 532 /** 533 * rxrpc_kernel_set_peer_data - Set app-specific data on a peer. 534 * @peer: The peer to alter 535 * @app_data: The data to set 536 * 537 * Set the app-specific data on a peer. AF_RXRPC makes no effort to retain 538 * anything the data might refer to. 539 * 540 * Return: The previous app_data. 541 */ 542 unsigned long rxrpc_kernel_set_peer_data(struct rxrpc_peer *peer, unsigned long app_data) 543 { 544 return xchg(&peer->app_data, app_data); 545 } 546 EXPORT_SYMBOL(rxrpc_kernel_set_peer_data); 547 548 /** 549 * rxrpc_kernel_get_peer_data - Get app-specific data from a peer. 550 * @peer: The peer to query 551 * 552 * Retrieve the app-specific data from a peer. 553 * 554 * Return: The peer's app data. 555 */ 556 unsigned long rxrpc_kernel_get_peer_data(const struct rxrpc_peer *peer) 557 { 558 return peer->app_data; 559 } 560 EXPORT_SYMBOL(rxrpc_kernel_get_peer_data); 561