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 _leave(" = %p {u=%d}", peer, refcount_read(&peer->ref)); 143 return peer; 144 } 145 146 /* 147 * assess the MTU size for the network interface through which this peer is 148 * reached 149 */ 150 static void rxrpc_assess_MTU_size(struct rxrpc_local *local, 151 struct rxrpc_peer *peer) 152 { 153 struct net *net = local->net; 154 struct dst_entry *dst; 155 struct rtable *rt; 156 struct flowi fl; 157 struct flowi4 *fl4 = &fl.u.ip4; 158 #ifdef CONFIG_AF_RXRPC_IPV6 159 struct flowi6 *fl6 = &fl.u.ip6; 160 #endif 161 162 peer->if_mtu = 1500; 163 164 memset(&fl, 0, sizeof(fl)); 165 switch (peer->srx.transport.family) { 166 case AF_INET: 167 rt = ip_route_output_ports( 168 net, fl4, NULL, 169 peer->srx.transport.sin.sin_addr.s_addr, 0, 170 htons(7000), htons(7001), IPPROTO_UDP, 0, 0); 171 if (IS_ERR(rt)) { 172 _leave(" [route err %ld]", PTR_ERR(rt)); 173 return; 174 } 175 dst = &rt->dst; 176 break; 177 178 #ifdef CONFIG_AF_RXRPC_IPV6 179 case AF_INET6: 180 fl6->flowi6_iif = LOOPBACK_IFINDEX; 181 fl6->flowi6_scope = RT_SCOPE_UNIVERSE; 182 fl6->flowi6_proto = IPPROTO_UDP; 183 memcpy(&fl6->daddr, &peer->srx.transport.sin6.sin6_addr, 184 sizeof(struct in6_addr)); 185 fl6->fl6_dport = htons(7001); 186 fl6->fl6_sport = htons(7000); 187 dst = ip6_route_output(net, NULL, fl6); 188 if (dst->error) { 189 _leave(" [route err %d]", dst->error); 190 return; 191 } 192 break; 193 #endif 194 195 default: 196 BUG(); 197 } 198 199 peer->if_mtu = dst_mtu(dst); 200 dst_release(dst); 201 202 _leave(" [if_mtu %u]", peer->if_mtu); 203 } 204 205 /* 206 * Allocate a peer. 207 */ 208 struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *local, gfp_t gfp, 209 enum rxrpc_peer_trace why) 210 { 211 struct rxrpc_peer *peer; 212 213 _enter(""); 214 215 peer = kzalloc(sizeof(struct rxrpc_peer), gfp); 216 if (peer) { 217 refcount_set(&peer->ref, 1); 218 peer->local = rxrpc_get_local(local, rxrpc_local_get_peer); 219 INIT_HLIST_HEAD(&peer->error_targets); 220 peer->service_conns = RB_ROOT; 221 seqlock_init(&peer->service_conn_lock); 222 spin_lock_init(&peer->lock); 223 spin_lock_init(&peer->rtt_input_lock); 224 peer->debug_id = atomic_inc_return(&rxrpc_debug_id); 225 226 rxrpc_peer_init_rtt(peer); 227 228 peer->cong_ssthresh = RXRPC_TX_MAX_WINDOW; 229 trace_rxrpc_peer(peer->debug_id, 1, why); 230 } 231 232 _leave(" = %p", peer); 233 return peer; 234 } 235 236 /* 237 * Initialise peer record. 238 */ 239 static void rxrpc_init_peer(struct rxrpc_local *local, struct rxrpc_peer *peer, 240 unsigned long hash_key) 241 { 242 peer->hash_key = hash_key; 243 rxrpc_assess_MTU_size(local, peer); 244 peer->mtu = peer->if_mtu; 245 peer->rtt_last_req = ktime_get_real(); 246 247 switch (peer->srx.transport.family) { 248 case AF_INET: 249 peer->hdrsize = sizeof(struct iphdr); 250 break; 251 #ifdef CONFIG_AF_RXRPC_IPV6 252 case AF_INET6: 253 peer->hdrsize = sizeof(struct ipv6hdr); 254 break; 255 #endif 256 default: 257 BUG(); 258 } 259 260 switch (peer->srx.transport_type) { 261 case SOCK_DGRAM: 262 peer->hdrsize += sizeof(struct udphdr); 263 break; 264 default: 265 BUG(); 266 } 267 268 peer->hdrsize += sizeof(struct rxrpc_wire_header); 269 peer->maxdata = peer->mtu - peer->hdrsize; 270 } 271 272 /* 273 * Set up a new peer. 274 */ 275 static struct rxrpc_peer *rxrpc_create_peer(struct rxrpc_local *local, 276 struct sockaddr_rxrpc *srx, 277 unsigned long hash_key, 278 gfp_t gfp) 279 { 280 struct rxrpc_peer *peer; 281 282 _enter(""); 283 284 peer = rxrpc_alloc_peer(local, gfp, rxrpc_peer_new_client); 285 if (peer) { 286 memcpy(&peer->srx, srx, sizeof(*srx)); 287 rxrpc_init_peer(local, peer, hash_key); 288 } 289 290 _leave(" = %p", peer); 291 return peer; 292 } 293 294 static void rxrpc_free_peer(struct rxrpc_peer *peer) 295 { 296 trace_rxrpc_peer(peer->debug_id, 0, rxrpc_peer_free); 297 rxrpc_put_local(peer->local, rxrpc_local_put_peer); 298 kfree_rcu(peer, rcu); 299 } 300 301 /* 302 * Set up a new incoming peer. There shouldn't be any other matching peers 303 * since we've already done a search in the list from the non-reentrant context 304 * (the data_ready handler) that is the only place we can add new peers. 305 */ 306 void rxrpc_new_incoming_peer(struct rxrpc_local *local, struct rxrpc_peer *peer) 307 { 308 struct rxrpc_net *rxnet = local->rxnet; 309 unsigned long hash_key; 310 311 hash_key = rxrpc_peer_hash_key(local, &peer->srx); 312 rxrpc_init_peer(local, peer, hash_key); 313 314 spin_lock(&rxnet->peer_hash_lock); 315 hash_add_rcu(rxnet->peer_hash, &peer->hash_link, hash_key); 316 list_add_tail(&peer->keepalive_link, &rxnet->peer_keepalive_new); 317 spin_unlock(&rxnet->peer_hash_lock); 318 } 319 320 /* 321 * obtain a remote transport endpoint for the specified address 322 */ 323 struct rxrpc_peer *rxrpc_lookup_peer(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, rxrpc_peer_get_lookup_client)) 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(local, srx, hash_key, gfp); 344 if (!candidate) { 345 _leave(" = NULL [nomem]"); 346 return NULL; 347 } 348 349 spin_lock(&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, rxrpc_peer_get_lookup_client)) 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(&rxnet->peer_hash_lock); 363 364 if (peer) 365 rxrpc_free_peer(candidate); 366 else 367 peer = candidate; 368 } 369 370 _leave(" = %p {u=%d}", peer, refcount_read(&peer->ref)); 371 return peer; 372 } 373 374 /* 375 * Get a ref on a peer record. 376 */ 377 struct rxrpc_peer *rxrpc_get_peer(struct rxrpc_peer *peer, enum rxrpc_peer_trace why) 378 { 379 int r; 380 381 __refcount_inc(&peer->ref, &r); 382 trace_rxrpc_peer(peer->debug_id, r + 1, why); 383 return peer; 384 } 385 386 /* 387 * Get a ref on a peer record unless its usage has already reached 0. 388 */ 389 struct rxrpc_peer *rxrpc_get_peer_maybe(struct rxrpc_peer *peer, 390 enum rxrpc_peer_trace why) 391 { 392 int r; 393 394 if (peer) { 395 if (__refcount_inc_not_zero(&peer->ref, &r)) 396 trace_rxrpc_peer(peer->debug_id, r + 1, why); 397 else 398 peer = NULL; 399 } 400 return peer; 401 } 402 403 /* 404 * Discard a peer record. 405 */ 406 static void __rxrpc_put_peer(struct rxrpc_peer *peer) 407 { 408 struct rxrpc_net *rxnet = peer->local->rxnet; 409 410 ASSERT(hlist_empty(&peer->error_targets)); 411 412 spin_lock(&rxnet->peer_hash_lock); 413 hash_del_rcu(&peer->hash_link); 414 list_del_init(&peer->keepalive_link); 415 spin_unlock(&rxnet->peer_hash_lock); 416 417 rxrpc_free_peer(peer); 418 } 419 420 /* 421 * Drop a ref on a peer record. 422 */ 423 void rxrpc_put_peer(struct rxrpc_peer *peer, enum rxrpc_peer_trace why) 424 { 425 unsigned int debug_id; 426 bool dead; 427 int r; 428 429 if (peer) { 430 debug_id = peer->debug_id; 431 dead = __refcount_dec_and_test(&peer->ref, &r); 432 trace_rxrpc_peer(debug_id, r - 1, why); 433 if (dead) 434 __rxrpc_put_peer(peer); 435 } 436 } 437 438 /* 439 * Make sure all peer records have been discarded. 440 */ 441 void rxrpc_destroy_all_peers(struct rxrpc_net *rxnet) 442 { 443 struct rxrpc_peer *peer; 444 int i; 445 446 for (i = 0; i < HASH_SIZE(rxnet->peer_hash); i++) { 447 if (hlist_empty(&rxnet->peer_hash[i])) 448 continue; 449 450 hlist_for_each_entry(peer, &rxnet->peer_hash[i], hash_link) { 451 pr_err("Leaked peer %u {%u} %pISp\n", 452 peer->debug_id, 453 refcount_read(&peer->ref), 454 &peer->srx.transport); 455 } 456 } 457 } 458 459 /** 460 * rxrpc_kernel_get_peer - Get the peer address of a call 461 * @sock: The socket on which the call is in progress. 462 * @call: The call to query 463 * @_srx: Where to place the result 464 * 465 * Get the address of the remote peer in a call. 466 */ 467 void rxrpc_kernel_get_peer(struct socket *sock, struct rxrpc_call *call, 468 struct sockaddr_rxrpc *_srx) 469 { 470 *_srx = call->peer->srx; 471 } 472 EXPORT_SYMBOL(rxrpc_kernel_get_peer); 473 474 /** 475 * rxrpc_kernel_get_srtt - Get a call's peer smoothed RTT 476 * @sock: The socket on which the call is in progress. 477 * @call: The call to query 478 * @_srtt: Where to store the SRTT value. 479 * 480 * Get the call's peer smoothed RTT in uS. 481 */ 482 bool rxrpc_kernel_get_srtt(struct socket *sock, struct rxrpc_call *call, 483 u32 *_srtt) 484 { 485 struct rxrpc_peer *peer = call->peer; 486 487 if (peer->rtt_count == 0) { 488 *_srtt = 1000000; /* 1S */ 489 return false; 490 } 491 492 *_srtt = call->peer->srtt_us >> 3; 493 return true; 494 } 495 EXPORT_SYMBOL(rxrpc_kernel_get_srtt); 496