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 /* 26 * Hash a peer key. 27 */ 28 static unsigned long rxrpc_peer_hash_key(struct rxrpc_local *local, 29 const struct sockaddr_rxrpc *srx) 30 { 31 const u16 *p; 32 unsigned int i, size; 33 unsigned long hash_key; 34 35 _enter(""); 36 37 hash_key = (unsigned long)local / __alignof__(*local); 38 hash_key += srx->transport_type; 39 hash_key += srx->transport_len; 40 hash_key += srx->transport.family; 41 42 switch (srx->transport.family) { 43 case AF_INET: 44 hash_key += (u16 __force)srx->transport.sin.sin_port; 45 size = sizeof(srx->transport.sin.sin_addr); 46 p = (u16 *)&srx->transport.sin.sin_addr; 47 break; 48 #ifdef CONFIG_AF_RXRPC_IPV6 49 case AF_INET6: 50 hash_key += (u16 __force)srx->transport.sin.sin_port; 51 size = sizeof(srx->transport.sin6.sin6_addr); 52 p = (u16 *)&srx->transport.sin6.sin6_addr; 53 break; 54 #endif 55 default: 56 WARN(1, "AF_RXRPC: Unsupported transport address family\n"); 57 return 0; 58 } 59 60 /* Step through the peer address in 16-bit portions for speed */ 61 for (i = 0; i < size; i += sizeof(*p), p++) 62 hash_key += *p; 63 64 _leave(" 0x%lx", hash_key); 65 return hash_key; 66 } 67 68 /* 69 * Compare a peer to a key. Return -ve, 0 or +ve to indicate less than, same 70 * or greater than. 71 * 72 * Unfortunately, the primitives in linux/hashtable.h don't allow for sorted 73 * buckets and mid-bucket insertion, so we don't make full use of this 74 * information at this point. 75 */ 76 static long rxrpc_peer_cmp_key(const struct rxrpc_peer *peer, 77 struct rxrpc_local *local, 78 const struct sockaddr_rxrpc *srx, 79 unsigned long hash_key) 80 { 81 long diff; 82 83 diff = ((peer->hash_key - hash_key) ?: 84 ((unsigned long)peer->local - (unsigned long)local) ?: 85 (peer->srx.transport_type - srx->transport_type) ?: 86 (peer->srx.transport_len - srx->transport_len) ?: 87 (peer->srx.transport.family - srx->transport.family)); 88 if (diff != 0) 89 return diff; 90 91 switch (srx->transport.family) { 92 case AF_INET: 93 return ((u16 __force)peer->srx.transport.sin.sin_port - 94 (u16 __force)srx->transport.sin.sin_port) ?: 95 memcmp(&peer->srx.transport.sin.sin_addr, 96 &srx->transport.sin.sin_addr, 97 sizeof(struct in_addr)); 98 #ifdef CONFIG_AF_RXRPC_IPV6 99 case AF_INET6: 100 return ((u16 __force)peer->srx.transport.sin6.sin6_port - 101 (u16 __force)srx->transport.sin6.sin6_port) ?: 102 memcmp(&peer->srx.transport.sin6.sin6_addr, 103 &srx->transport.sin6.sin6_addr, 104 sizeof(struct in6_addr)); 105 #endif 106 default: 107 BUG(); 108 } 109 } 110 111 /* 112 * Look up a remote transport endpoint for the specified address using RCU. 113 */ 114 static struct rxrpc_peer *__rxrpc_lookup_peer_rcu( 115 struct rxrpc_local *local, 116 const struct sockaddr_rxrpc *srx, 117 unsigned long hash_key) 118 { 119 struct rxrpc_peer *peer; 120 struct rxrpc_net *rxnet = local->rxnet; 121 122 hash_for_each_possible_rcu(rxnet->peer_hash, peer, hash_link, hash_key) { 123 if (rxrpc_peer_cmp_key(peer, local, srx, hash_key) == 0 && 124 refcount_read(&peer->ref) > 0) 125 return peer; 126 } 127 128 return NULL; 129 } 130 131 /* 132 * Look up a remote transport endpoint for the specified address using RCU. 133 */ 134 struct rxrpc_peer *rxrpc_lookup_peer_rcu(struct rxrpc_local *local, 135 const struct sockaddr_rxrpc *srx) 136 { 137 struct rxrpc_peer *peer; 138 unsigned long hash_key = rxrpc_peer_hash_key(local, srx); 139 140 peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key); 141 if (peer) { 142 _net("PEER %d {%pISp}", peer->debug_id, &peer->srx.transport); 143 _leave(" = %p {u=%d}", peer, refcount_read(&peer->ref)); 144 } 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_sock *rx, 153 struct rxrpc_peer *peer) 154 { 155 struct net *net = sock_net(&rx->sk); 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 { 212 const void *here = __builtin_return_address(0); 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); 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, rxrpc_peer_new, 1, here); 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_sock *rx, struct rxrpc_peer *peer, 242 unsigned long hash_key) 243 { 244 peer->hash_key = hash_key; 245 rxrpc_assess_MTU_size(rx, 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_sock *rx, 278 struct rxrpc_local *local, 279 struct sockaddr_rxrpc *srx, 280 unsigned long hash_key, 281 gfp_t gfp) 282 { 283 struct rxrpc_peer *peer; 284 285 _enter(""); 286 287 peer = rxrpc_alloc_peer(local, gfp); 288 if (peer) { 289 memcpy(&peer->srx, srx, sizeof(*srx)); 290 rxrpc_init_peer(rx, peer, hash_key); 291 } 292 293 _leave(" = %p", peer); 294 return peer; 295 } 296 297 static void rxrpc_free_peer(struct rxrpc_peer *peer) 298 { 299 rxrpc_put_local(peer->local); 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_sock *rx, struct rxrpc_local *local, 309 struct rxrpc_peer *peer) 310 { 311 struct rxrpc_net *rxnet = local->rxnet; 312 unsigned long hash_key; 313 314 hash_key = rxrpc_peer_hash_key(local, &peer->srx); 315 rxrpc_init_peer(rx, peer, hash_key); 316 317 spin_lock(&rxnet->peer_hash_lock); 318 hash_add_rcu(rxnet->peer_hash, &peer->hash_link, hash_key); 319 list_add_tail(&peer->keepalive_link, &rxnet->peer_keepalive_new); 320 spin_unlock(&rxnet->peer_hash_lock); 321 } 322 323 /* 324 * obtain a remote transport endpoint for the specified address 325 */ 326 struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_sock *rx, 327 struct rxrpc_local *local, 328 struct sockaddr_rxrpc *srx, gfp_t gfp) 329 { 330 struct rxrpc_peer *peer, *candidate; 331 struct rxrpc_net *rxnet = local->rxnet; 332 unsigned long hash_key = rxrpc_peer_hash_key(local, srx); 333 334 _enter("{%pISp}", &srx->transport); 335 336 /* search the peer list first */ 337 rcu_read_lock(); 338 peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key); 339 if (peer && !rxrpc_get_peer_maybe(peer)) 340 peer = NULL; 341 rcu_read_unlock(); 342 343 if (!peer) { 344 /* The peer is not yet present in hash - create a candidate 345 * for a new record and then redo the search. 346 */ 347 candidate = rxrpc_create_peer(rx, local, srx, hash_key, gfp); 348 if (!candidate) { 349 _leave(" = NULL [nomem]"); 350 return NULL; 351 } 352 353 spin_lock_bh(&rxnet->peer_hash_lock); 354 355 /* Need to check that we aren't racing with someone else */ 356 peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key); 357 if (peer && !rxrpc_get_peer_maybe(peer)) 358 peer = NULL; 359 if (!peer) { 360 hash_add_rcu(rxnet->peer_hash, 361 &candidate->hash_link, hash_key); 362 list_add_tail(&candidate->keepalive_link, 363 &rxnet->peer_keepalive_new); 364 } 365 366 spin_unlock_bh(&rxnet->peer_hash_lock); 367 368 if (peer) 369 rxrpc_free_peer(candidate); 370 else 371 peer = candidate; 372 } 373 374 _net("PEER %d {%pISp}", peer->debug_id, &peer->srx.transport); 375 376 _leave(" = %p {u=%d}", peer, refcount_read(&peer->ref)); 377 return peer; 378 } 379 380 /* 381 * Get a ref on a peer record. 382 */ 383 struct rxrpc_peer *rxrpc_get_peer(struct rxrpc_peer *peer) 384 { 385 const void *here = __builtin_return_address(0); 386 int r; 387 388 __refcount_inc(&peer->ref, &r); 389 trace_rxrpc_peer(peer->debug_id, rxrpc_peer_got, r + 1, here); 390 return peer; 391 } 392 393 /* 394 * Get a ref on a peer record unless its usage has already reached 0. 395 */ 396 struct rxrpc_peer *rxrpc_get_peer_maybe(struct rxrpc_peer *peer) 397 { 398 const void *here = __builtin_return_address(0); 399 int r; 400 401 if (peer) { 402 if (__refcount_inc_not_zero(&peer->ref, &r)) 403 trace_rxrpc_peer(peer->debug_id, rxrpc_peer_got, r + 1, here); 404 else 405 peer = NULL; 406 } 407 return peer; 408 } 409 410 /* 411 * Discard a peer record. 412 */ 413 static void __rxrpc_put_peer(struct rxrpc_peer *peer) 414 { 415 struct rxrpc_net *rxnet = peer->local->rxnet; 416 417 ASSERT(hlist_empty(&peer->error_targets)); 418 419 spin_lock_bh(&rxnet->peer_hash_lock); 420 hash_del_rcu(&peer->hash_link); 421 list_del_init(&peer->keepalive_link); 422 spin_unlock_bh(&rxnet->peer_hash_lock); 423 424 rxrpc_free_peer(peer); 425 } 426 427 /* 428 * Drop a ref on a peer record. 429 */ 430 void rxrpc_put_peer(struct rxrpc_peer *peer) 431 { 432 const void *here = __builtin_return_address(0); 433 unsigned int debug_id; 434 bool dead; 435 int r; 436 437 if (peer) { 438 debug_id = peer->debug_id; 439 dead = __refcount_dec_and_test(&peer->ref, &r); 440 trace_rxrpc_peer(debug_id, rxrpc_peer_put, r - 1, here); 441 if (dead) 442 __rxrpc_put_peer(peer); 443 } 444 } 445 446 /* 447 * Drop a ref on a peer record where the caller already holds the 448 * peer_hash_lock. 449 */ 450 void rxrpc_put_peer_locked(struct rxrpc_peer *peer) 451 { 452 const void *here = __builtin_return_address(0); 453 unsigned int debug_id = peer->debug_id; 454 bool dead; 455 int r; 456 457 dead = __refcount_dec_and_test(&peer->ref, &r); 458 trace_rxrpc_peer(debug_id, rxrpc_peer_put, r - 1, here); 459 if (dead) { 460 hash_del_rcu(&peer->hash_link); 461 list_del_init(&peer->keepalive_link); 462 rxrpc_free_peer(peer); 463 } 464 } 465 466 /* 467 * Make sure all peer records have been discarded. 468 */ 469 void rxrpc_destroy_all_peers(struct rxrpc_net *rxnet) 470 { 471 struct rxrpc_peer *peer; 472 int i; 473 474 for (i = 0; i < HASH_SIZE(rxnet->peer_hash); i++) { 475 if (hlist_empty(&rxnet->peer_hash[i])) 476 continue; 477 478 hlist_for_each_entry(peer, &rxnet->peer_hash[i], hash_link) { 479 pr_err("Leaked peer %u {%u} %pISp\n", 480 peer->debug_id, 481 refcount_read(&peer->ref), 482 &peer->srx.transport); 483 } 484 } 485 } 486 487 /** 488 * rxrpc_kernel_get_peer - Get the peer address of a call 489 * @sock: The socket on which the call is in progress. 490 * @call: The call to query 491 * @_srx: Where to place the result 492 * 493 * Get the address of the remote peer in a call. 494 */ 495 void rxrpc_kernel_get_peer(struct socket *sock, struct rxrpc_call *call, 496 struct sockaddr_rxrpc *_srx) 497 { 498 *_srx = call->peer->srx; 499 } 500 EXPORT_SYMBOL(rxrpc_kernel_get_peer); 501 502 /** 503 * rxrpc_kernel_get_srtt - Get a call's peer smoothed RTT 504 * @sock: The socket on which the call is in progress. 505 * @call: The call to query 506 * @_srtt: Where to store the SRTT value. 507 * 508 * Get the call's peer smoothed RTT in uS. 509 */ 510 bool rxrpc_kernel_get_srtt(struct socket *sock, struct rxrpc_call *call, 511 u32 *_srtt) 512 { 513 struct rxrpc_peer *peer = call->peer; 514 515 if (peer->rtt_count == 0) { 516 *_srtt = 1000000; /* 1S */ 517 return false; 518 } 519 520 *_srtt = call->peer->srtt_us >> 3; 521 return true; 522 } 523 EXPORT_SYMBOL(rxrpc_kernel_get_srtt); 524