1 /* RxRPC remote transport endpoint record management 2 * 3 * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved. 4 * Written by David Howells (dhowells@redhat.com) 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License 8 * as published by the Free Software Foundation; either version 9 * 2 of the License, or (at your option) any later version. 10 */ 11 12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 13 14 #include <linux/module.h> 15 #include <linux/net.h> 16 #include <linux/skbuff.h> 17 #include <linux/udp.h> 18 #include <linux/in.h> 19 #include <linux/in6.h> 20 #include <linux/slab.h> 21 #include <linux/hashtable.h> 22 #include <net/sock.h> 23 #include <net/af_rxrpc.h> 24 #include <net/ip.h> 25 #include <net/route.h> 26 #include <net/ip6_route.h> 27 #include "ar-internal.h" 28 29 static DEFINE_HASHTABLE(rxrpc_peer_hash, 10); 30 static DEFINE_SPINLOCK(rxrpc_peer_hash_lock); 31 32 /* 33 * Hash a peer key. 34 */ 35 static unsigned long rxrpc_peer_hash_key(struct rxrpc_local *local, 36 const struct sockaddr_rxrpc *srx) 37 { 38 const u16 *p; 39 unsigned int i, size; 40 unsigned long hash_key; 41 42 _enter(""); 43 44 hash_key = (unsigned long)local / __alignof__(*local); 45 hash_key += srx->transport_type; 46 hash_key += srx->transport_len; 47 hash_key += srx->transport.family; 48 49 switch (srx->transport.family) { 50 case AF_INET: 51 hash_key += (u16 __force)srx->transport.sin.sin_port; 52 size = sizeof(srx->transport.sin.sin_addr); 53 p = (u16 *)&srx->transport.sin.sin_addr; 54 break; 55 #ifdef CONFIG_AF_RXRPC_IPV6 56 case AF_INET6: 57 hash_key += (u16 __force)srx->transport.sin.sin_port; 58 size = sizeof(srx->transport.sin6.sin6_addr); 59 p = (u16 *)&srx->transport.sin6.sin6_addr; 60 break; 61 #endif 62 default: 63 WARN(1, "AF_RXRPC: Unsupported transport address family\n"); 64 return 0; 65 } 66 67 /* Step through the peer address in 16-bit portions for speed */ 68 for (i = 0; i < size; i += sizeof(*p), p++) 69 hash_key += *p; 70 71 _leave(" 0x%lx", hash_key); 72 return hash_key; 73 } 74 75 /* 76 * Compare a peer to a key. Return -ve, 0 or +ve to indicate less than, same 77 * or greater than. 78 * 79 * Unfortunately, the primitives in linux/hashtable.h don't allow for sorted 80 * buckets and mid-bucket insertion, so we don't make full use of this 81 * information at this point. 82 */ 83 static long rxrpc_peer_cmp_key(const struct rxrpc_peer *peer, 84 struct rxrpc_local *local, 85 const struct sockaddr_rxrpc *srx, 86 unsigned long hash_key) 87 { 88 long diff; 89 90 diff = ((peer->hash_key - hash_key) ?: 91 ((unsigned long)peer->local - (unsigned long)local) ?: 92 (peer->srx.transport_type - srx->transport_type) ?: 93 (peer->srx.transport_len - srx->transport_len) ?: 94 (peer->srx.transport.family - srx->transport.family)); 95 if (diff != 0) 96 return diff; 97 98 switch (srx->transport.family) { 99 case AF_INET: 100 return ((u16 __force)peer->srx.transport.sin.sin_port - 101 (u16 __force)srx->transport.sin.sin_port) ?: 102 memcmp(&peer->srx.transport.sin.sin_addr, 103 &srx->transport.sin.sin_addr, 104 sizeof(struct in_addr)); 105 #ifdef CONFIG_AF_RXRPC_IPV6 106 case AF_INET6: 107 return ((u16 __force)peer->srx.transport.sin6.sin6_port - 108 (u16 __force)srx->transport.sin6.sin6_port) ?: 109 memcmp(&peer->srx.transport.sin6.sin6_addr, 110 &srx->transport.sin6.sin6_addr, 111 sizeof(struct in6_addr)); 112 #endif 113 default: 114 BUG(); 115 } 116 } 117 118 /* 119 * Look up a remote transport endpoint for the specified address using RCU. 120 */ 121 static struct rxrpc_peer *__rxrpc_lookup_peer_rcu( 122 struct rxrpc_local *local, 123 const struct sockaddr_rxrpc *srx, 124 unsigned long hash_key) 125 { 126 struct rxrpc_peer *peer; 127 128 hash_for_each_possible_rcu(rxrpc_peer_hash, peer, hash_link, hash_key) { 129 if (rxrpc_peer_cmp_key(peer, local, srx, hash_key) == 0) { 130 if (atomic_read(&peer->usage) == 0) 131 return NULL; 132 return peer; 133 } 134 } 135 136 return NULL; 137 } 138 139 /* 140 * Look up a remote transport endpoint for the specified address using RCU. 141 */ 142 struct rxrpc_peer *rxrpc_lookup_peer_rcu(struct rxrpc_local *local, 143 const struct sockaddr_rxrpc *srx) 144 { 145 struct rxrpc_peer *peer; 146 unsigned long hash_key = rxrpc_peer_hash_key(local, srx); 147 148 peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key); 149 if (peer) { 150 _net("PEER %d {%pISp}", peer->debug_id, &peer->srx.transport); 151 _leave(" = %p {u=%d}", peer, atomic_read(&peer->usage)); 152 } 153 return peer; 154 } 155 156 /* 157 * assess the MTU size for the network interface through which this peer is 158 * reached 159 */ 160 static void rxrpc_assess_MTU_size(struct rxrpc_peer *peer) 161 { 162 struct dst_entry *dst; 163 struct rtable *rt; 164 struct flowi fl; 165 struct flowi4 *fl4 = &fl.u.ip4; 166 #ifdef CONFIG_AF_RXRPC_IPV6 167 struct flowi6 *fl6 = &fl.u.ip6; 168 #endif 169 170 peer->if_mtu = 1500; 171 172 memset(&fl, 0, sizeof(fl)); 173 switch (peer->srx.transport.family) { 174 case AF_INET: 175 rt = ip_route_output_ports( 176 &init_net, fl4, NULL, 177 peer->srx.transport.sin.sin_addr.s_addr, 0, 178 htons(7000), htons(7001), IPPROTO_UDP, 0, 0); 179 if (IS_ERR(rt)) { 180 _leave(" [route err %ld]", PTR_ERR(rt)); 181 return; 182 } 183 dst = &rt->dst; 184 break; 185 186 #ifdef CONFIG_AF_RXRPC_IPV6 187 case AF_INET6: 188 fl6->flowi6_iif = LOOPBACK_IFINDEX; 189 fl6->flowi6_scope = RT_SCOPE_UNIVERSE; 190 fl6->flowi6_proto = IPPROTO_UDP; 191 memcpy(&fl6->daddr, &peer->srx.transport.sin6.sin6_addr, 192 sizeof(struct in6_addr)); 193 fl6->fl6_dport = htons(7001); 194 fl6->fl6_sport = htons(7000); 195 dst = ip6_route_output(&init_net, NULL, fl6); 196 if (IS_ERR(dst)) { 197 _leave(" [route err %ld]", PTR_ERR(dst)); 198 return; 199 } 200 break; 201 #endif 202 203 default: 204 BUG(); 205 } 206 207 peer->if_mtu = dst_mtu(dst); 208 dst_release(dst); 209 210 _leave(" [if_mtu %u]", peer->if_mtu); 211 } 212 213 /* 214 * Allocate a peer. 215 */ 216 struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *local, gfp_t gfp) 217 { 218 struct rxrpc_peer *peer; 219 220 _enter(""); 221 222 peer = kzalloc(sizeof(struct rxrpc_peer), gfp); 223 if (peer) { 224 atomic_set(&peer->usage, 1); 225 peer->local = local; 226 INIT_HLIST_HEAD(&peer->error_targets); 227 INIT_WORK(&peer->error_distributor, 228 &rxrpc_peer_error_distributor); 229 peer->service_conns = RB_ROOT; 230 seqlock_init(&peer->service_conn_lock); 231 spin_lock_init(&peer->lock); 232 peer->debug_id = atomic_inc_return(&rxrpc_debug_id); 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_peer *peer, unsigned long hash_key) 243 { 244 peer->hash_key = hash_key; 245 rxrpc_assess_MTU_size(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); 287 if (peer) { 288 memcpy(&peer->srx, srx, sizeof(*srx)); 289 rxrpc_init_peer(peer, hash_key); 290 } 291 292 _leave(" = %p", peer); 293 return peer; 294 } 295 296 /* 297 * Set up a new incoming peer. The address is prestored in the preallocated 298 * peer. 299 */ 300 struct rxrpc_peer *rxrpc_lookup_incoming_peer(struct rxrpc_local *local, 301 struct rxrpc_peer *prealloc) 302 { 303 struct rxrpc_peer *peer; 304 unsigned long hash_key; 305 306 hash_key = rxrpc_peer_hash_key(local, &prealloc->srx); 307 prealloc->local = local; 308 rxrpc_init_peer(prealloc, hash_key); 309 310 spin_lock(&rxrpc_peer_hash_lock); 311 312 /* Need to check that we aren't racing with someone else */ 313 peer = __rxrpc_lookup_peer_rcu(local, &prealloc->srx, hash_key); 314 if (peer && !rxrpc_get_peer_maybe(peer)) 315 peer = NULL; 316 if (!peer) { 317 peer = prealloc; 318 hash_add_rcu(rxrpc_peer_hash, &peer->hash_link, hash_key); 319 } 320 321 spin_unlock(&rxrpc_peer_hash_lock); 322 return peer; 323 } 324 325 /* 326 * obtain a remote transport endpoint for the specified address 327 */ 328 struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_local *local, 329 struct sockaddr_rxrpc *srx, gfp_t gfp) 330 { 331 struct rxrpc_peer *peer, *candidate; 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(local, srx, hash_key, gfp); 348 if (!candidate) { 349 _leave(" = NULL [nomem]"); 350 return NULL; 351 } 352 353 spin_lock_bh(&rxrpc_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(rxrpc_peer_hash, 361 &candidate->hash_link, hash_key); 362 363 spin_unlock_bh(&rxrpc_peer_hash_lock); 364 365 if (peer) 366 kfree(candidate); 367 else 368 peer = candidate; 369 } 370 371 _net("PEER %d {%pISp}", peer->debug_id, &peer->srx.transport); 372 373 _leave(" = %p {u=%d}", peer, atomic_read(&peer->usage)); 374 return peer; 375 } 376 377 /* 378 * Discard a ref on a remote peer record. 379 */ 380 void __rxrpc_put_peer(struct rxrpc_peer *peer) 381 { 382 ASSERT(hlist_empty(&peer->error_targets)); 383 384 spin_lock_bh(&rxrpc_peer_hash_lock); 385 hash_del_rcu(&peer->hash_link); 386 spin_unlock_bh(&rxrpc_peer_hash_lock); 387 388 kfree_rcu(peer, rcu); 389 } 390 391 /** 392 * rxrpc_kernel_get_peer - Get the peer address of a call 393 * @sock: The socket on which the call is in progress. 394 * @call: The call to query 395 * @_srx: Where to place the result 396 * 397 * Get the address of the remote peer in a call. 398 */ 399 void rxrpc_kernel_get_peer(struct socket *sock, struct rxrpc_call *call, 400 struct sockaddr_rxrpc *_srx) 401 { 402 *_srx = call->peer->srx; 403 } 404 EXPORT_SYMBOL(rxrpc_kernel_get_peer); 405