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 atomic_read(&peer->usage) > 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, atomic_read(&peer->usage)); 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 struct rxrpc_peer *peer; 213 214 _enter(""); 215 216 peer = kzalloc(sizeof(struct rxrpc_peer), gfp); 217 if (peer) { 218 atomic_set(&peer->usage, 1); 219 peer->local = local; 220 INIT_HLIST_HEAD(&peer->error_targets); 221 peer->service_conns = RB_ROOT; 222 seqlock_init(&peer->service_conn_lock); 223 spin_lock_init(&peer->lock); 224 spin_lock_init(&peer->rtt_input_lock); 225 peer->debug_id = atomic_inc_return(&rxrpc_debug_id); 226 227 if (RXRPC_TX_SMSS > 2190) 228 peer->cong_cwnd = 2; 229 else if (RXRPC_TX_SMSS > 1095) 230 peer->cong_cwnd = 3; 231 else 232 peer->cong_cwnd = 4; 233 } 234 235 _leave(" = %p", peer); 236 return peer; 237 } 238 239 /* 240 * Initialise peer record. 241 */ 242 static void rxrpc_init_peer(struct rxrpc_sock *rx, struct rxrpc_peer *peer, 243 unsigned long hash_key) 244 { 245 peer->hash_key = hash_key; 246 rxrpc_assess_MTU_size(rx, peer); 247 peer->mtu = peer->if_mtu; 248 peer->rtt_last_req = ktime_get_real(); 249 250 switch (peer->srx.transport.family) { 251 case AF_INET: 252 peer->hdrsize = sizeof(struct iphdr); 253 break; 254 #ifdef CONFIG_AF_RXRPC_IPV6 255 case AF_INET6: 256 peer->hdrsize = sizeof(struct ipv6hdr); 257 break; 258 #endif 259 default: 260 BUG(); 261 } 262 263 switch (peer->srx.transport_type) { 264 case SOCK_DGRAM: 265 peer->hdrsize += sizeof(struct udphdr); 266 break; 267 default: 268 BUG(); 269 } 270 271 peer->hdrsize += sizeof(struct rxrpc_wire_header); 272 peer->maxdata = peer->mtu - peer->hdrsize; 273 } 274 275 /* 276 * Set up a new peer. 277 */ 278 static struct rxrpc_peer *rxrpc_create_peer(struct rxrpc_sock *rx, 279 struct rxrpc_local *local, 280 struct sockaddr_rxrpc *srx, 281 unsigned long hash_key, 282 gfp_t gfp) 283 { 284 struct rxrpc_peer *peer; 285 286 _enter(""); 287 288 peer = rxrpc_alloc_peer(local, gfp); 289 if (peer) { 290 memcpy(&peer->srx, srx, sizeof(*srx)); 291 rxrpc_init_peer(rx, peer, hash_key); 292 } 293 294 _leave(" = %p", peer); 295 return peer; 296 } 297 298 /* 299 * Set up a new incoming peer. There shouldn't be any other matching peers 300 * since we've already done a search in the list from the non-reentrant context 301 * (the data_ready handler) that is the only place we can add new peers. 302 */ 303 void rxrpc_new_incoming_peer(struct rxrpc_sock *rx, struct rxrpc_local *local, 304 struct rxrpc_peer *peer) 305 { 306 struct rxrpc_net *rxnet = local->rxnet; 307 unsigned long hash_key; 308 309 hash_key = rxrpc_peer_hash_key(local, &peer->srx); 310 peer->local = local; 311 rxrpc_init_peer(rx, peer, hash_key); 312 313 spin_lock(&rxnet->peer_hash_lock); 314 hash_add_rcu(rxnet->peer_hash, &peer->hash_link, hash_key); 315 list_add_tail(&peer->keepalive_link, &rxnet->peer_keepalive_new); 316 spin_unlock(&rxnet->peer_hash_lock); 317 } 318 319 /* 320 * obtain a remote transport endpoint for the specified address 321 */ 322 struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_sock *rx, 323 struct rxrpc_local *local, 324 struct sockaddr_rxrpc *srx, gfp_t gfp) 325 { 326 struct rxrpc_peer *peer, *candidate; 327 struct rxrpc_net *rxnet = local->rxnet; 328 unsigned long hash_key = rxrpc_peer_hash_key(local, srx); 329 330 _enter("{%pISp}", &srx->transport); 331 332 /* search the peer list first */ 333 rcu_read_lock(); 334 peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key); 335 if (peer && !rxrpc_get_peer_maybe(peer)) 336 peer = NULL; 337 rcu_read_unlock(); 338 339 if (!peer) { 340 /* The peer is not yet present in hash - create a candidate 341 * for a new record and then redo the search. 342 */ 343 candidate = rxrpc_create_peer(rx, local, srx, hash_key, gfp); 344 if (!candidate) { 345 _leave(" = NULL [nomem]"); 346 return NULL; 347 } 348 349 spin_lock_bh(&rxnet->peer_hash_lock); 350 351 /* Need to check that we aren't racing with someone else */ 352 peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key); 353 if (peer && !rxrpc_get_peer_maybe(peer)) 354 peer = NULL; 355 if (!peer) { 356 hash_add_rcu(rxnet->peer_hash, 357 &candidate->hash_link, hash_key); 358 list_add_tail(&candidate->keepalive_link, 359 &rxnet->peer_keepalive_new); 360 } 361 362 spin_unlock_bh(&rxnet->peer_hash_lock); 363 364 if (peer) 365 kfree(candidate); 366 else 367 peer = candidate; 368 } 369 370 _net("PEER %d {%pISp}", peer->debug_id, &peer->srx.transport); 371 372 _leave(" = %p {u=%d}", peer, atomic_read(&peer->usage)); 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) 380 { 381 const void *here = __builtin_return_address(0); 382 int n; 383 384 n = atomic_inc_return(&peer->usage); 385 trace_rxrpc_peer(peer, rxrpc_peer_got, n, here); 386 return peer; 387 } 388 389 /* 390 * Get a ref on a peer record unless its usage has already reached 0. 391 */ 392 struct rxrpc_peer *rxrpc_get_peer_maybe(struct rxrpc_peer *peer) 393 { 394 const void *here = __builtin_return_address(0); 395 396 if (peer) { 397 int n = atomic_fetch_add_unless(&peer->usage, 1, 0); 398 if (n > 0) 399 trace_rxrpc_peer(peer, rxrpc_peer_got, n + 1, here); 400 else 401 peer = NULL; 402 } 403 return peer; 404 } 405 406 /* 407 * Discard a peer record. 408 */ 409 static void __rxrpc_put_peer(struct rxrpc_peer *peer) 410 { 411 struct rxrpc_net *rxnet = peer->local->rxnet; 412 413 ASSERT(hlist_empty(&peer->error_targets)); 414 415 spin_lock_bh(&rxnet->peer_hash_lock); 416 hash_del_rcu(&peer->hash_link); 417 list_del_init(&peer->keepalive_link); 418 spin_unlock_bh(&rxnet->peer_hash_lock); 419 420 kfree_rcu(peer, rcu); 421 } 422 423 /* 424 * Drop a ref on a peer record. 425 */ 426 void rxrpc_put_peer(struct rxrpc_peer *peer) 427 { 428 const void *here = __builtin_return_address(0); 429 int n; 430 431 if (peer) { 432 n = atomic_dec_return(&peer->usage); 433 trace_rxrpc_peer(peer, rxrpc_peer_put, n, here); 434 if (n == 0) 435 __rxrpc_put_peer(peer); 436 } 437 } 438 439 /* 440 * Drop a ref on a peer record where the caller already holds the 441 * peer_hash_lock. 442 */ 443 void rxrpc_put_peer_locked(struct rxrpc_peer *peer) 444 { 445 const void *here = __builtin_return_address(0); 446 int n; 447 448 n = atomic_dec_return(&peer->usage); 449 trace_rxrpc_peer(peer, rxrpc_peer_put, n, here); 450 if (n == 0) { 451 hash_del_rcu(&peer->hash_link); 452 list_del_init(&peer->keepalive_link); 453 kfree_rcu(peer, rcu); 454 } 455 } 456 457 /* 458 * Make sure all peer records have been discarded. 459 */ 460 void rxrpc_destroy_all_peers(struct rxrpc_net *rxnet) 461 { 462 struct rxrpc_peer *peer; 463 int i; 464 465 for (i = 0; i < HASH_SIZE(rxnet->peer_hash); i++) { 466 if (hlist_empty(&rxnet->peer_hash[i])) 467 continue; 468 469 hlist_for_each_entry(peer, &rxnet->peer_hash[i], hash_link) { 470 pr_err("Leaked peer %u {%u} %pISp\n", 471 peer->debug_id, 472 atomic_read(&peer->usage), 473 &peer->srx.transport); 474 } 475 } 476 } 477 478 /** 479 * rxrpc_kernel_get_peer - Get the peer address of a call 480 * @sock: The socket on which the call is in progress. 481 * @call: The call to query 482 * @_srx: Where to place the result 483 * 484 * Get the address of the remote peer in a call. 485 */ 486 void rxrpc_kernel_get_peer(struct socket *sock, struct rxrpc_call *call, 487 struct sockaddr_rxrpc *_srx) 488 { 489 *_srx = call->peer->srx; 490 } 491 EXPORT_SYMBOL(rxrpc_kernel_get_peer); 492 493 /** 494 * rxrpc_kernel_get_rtt - Get a call's peer RTT 495 * @sock: The socket on which the call is in progress. 496 * @call: The call to query 497 * 498 * Get the call's peer RTT. 499 */ 500 u64 rxrpc_kernel_get_rtt(struct socket *sock, struct rxrpc_call *call) 501 { 502 return call->peer->rtt; 503 } 504 EXPORT_SYMBOL(rxrpc_kernel_get_rtt); 505