net/rxrpc/peer_object.c

   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 = rxrpc_get_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         rxrpc_init_peer(rx, peer, hash_key);
 311
 312         spin_lock(&rxnet->peer_hash_lock);
 313         hash_add_rcu(rxnet->peer_hash, &peer->hash_link, hash_key);
 314         list_add_tail(&peer->keepalive_link, &rxnet->peer_keepalive_new);
 315         spin_unlock(&rxnet->peer_hash_lock);
 316 }
 317
 318 /*
 319  * obtain a remote transport endpoint for the specified address
 320  */
 321 struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_sock *rx,
 322                                      struct rxrpc_local *local,
 323                                      struct sockaddr_rxrpc *srx, gfp_t gfp)
 324 {
 325         struct rxrpc_peer *peer, *candidate;
 326         struct rxrpc_net *rxnet = local->rxnet;
 327         unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
 328
 329         _enter("{%pISp}", &srx->transport);
 330
 331         /* search the peer list first */
 332         rcu_read_lock();
 333         peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
 334         if (peer && !rxrpc_get_peer_maybe(peer))
 335                 peer = NULL;
 336         rcu_read_unlock();
 337
 338         if (!peer) {
 339                 /* The peer is not yet present in hash - create a candidate
 340                  * for a new record and then redo the search.
 341                  */
 342                 candidate = rxrpc_create_peer(rx, local, srx, hash_key, gfp);
 343                 if (!candidate) {
 344                         _leave(" = NULL [nomem]");
 345                         return NULL;
 346                 }
 347
 348                 spin_lock_bh(&rxnet->peer_hash_lock);
 349
 350                 /* Need to check that we aren't racing with someone else */
 351                 peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
 352                 if (peer && !rxrpc_get_peer_maybe(peer))
 353                         peer = NULL;
 354                 if (!peer) {
 355                         hash_add_rcu(rxnet->peer_hash,
 356                                      &candidate->hash_link, hash_key);
 357                         list_add_tail(&candidate->keepalive_link,
 358                                       &rxnet->peer_keepalive_new);
 359                 }
 360
 361                 spin_unlock_bh(&rxnet->peer_hash_lock);
 362
 363                 if (peer)
 364                         kfree(candidate);
 365                 else
 366                         peer = candidate;
 367         }
 368
 369         _net("PEER %d {%pISp}", peer->debug_id, &peer->srx.transport);
 370
 371         _leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
 372         return peer;
 373 }
 374
 375 /*
 376  * Get a ref on a peer record.
 377  */
 378 struct rxrpc_peer *rxrpc_get_peer(struct rxrpc_peer *peer)
 379 {
 380         const void *here = __builtin_return_address(0);
 381         int n;
 382
 383         n = atomic_inc_return(&peer->usage);
 384         trace_rxrpc_peer(peer->debug_id, rxrpc_peer_got, n, here);
 385         return peer;
 386 }
 387
 388 /*
 389  * Get a ref on a peer record unless its usage has already reached 0.
 390  */
 391 struct rxrpc_peer *rxrpc_get_peer_maybe(struct rxrpc_peer *peer)
 392 {
 393         const void *here = __builtin_return_address(0);
 394
 395         if (peer) {
 396                 int n = atomic_fetch_add_unless(&peer->usage, 1, 0);
 397                 if (n > 0)
 398                         trace_rxrpc_peer(peer->debug_id, rxrpc_peer_got, n + 1, here);
 399                 else
 400                         peer = NULL;
 401         }
 402         return peer;
 403 }
 404
 405 /*
 406  * Discard a peer record.
 407  */
 408 static void __rxrpc_put_peer(struct rxrpc_peer *peer)
 409 {
 410         struct rxrpc_net *rxnet = peer->local->rxnet;
 411
 412         ASSERT(hlist_empty(&peer->error_targets));
 413
 414         spin_lock_bh(&rxnet->peer_hash_lock);
 415         hash_del_rcu(&peer->hash_link);
 416         list_del_init(&peer->keepalive_link);
 417         spin_unlock_bh(&rxnet->peer_hash_lock);
 418
 419         rxrpc_put_local(peer->local);
 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         unsigned int debug_id;
 430         int n;
 431
 432         if (peer) {
 433                 debug_id = peer->debug_id;
 434                 n = atomic_dec_return(&peer->usage);
 435                 trace_rxrpc_peer(debug_id, rxrpc_peer_put, n, here);
 436                 if (n == 0)
 437                         __rxrpc_put_peer(peer);
 438         }
 439 }
 440
 441 /*
 442  * Drop a ref on a peer record where the caller already holds the
 443  * peer_hash_lock.
 444  */
 445 void rxrpc_put_peer_locked(struct rxrpc_peer *peer)
 446 {
 447         const void *here = __builtin_return_address(0);
 448         unsigned int debug_id = peer->debug_id;
 449         int n;
 450
 451         n = atomic_dec_return(&peer->usage);
 452         trace_rxrpc_peer(debug_id, rxrpc_peer_put, n, here);
 453         if (n == 0) {
 454                 hash_del_rcu(&peer->hash_link);
 455                 list_del_init(&peer->keepalive_link);
 456                 rxrpc_put_local(peer->local);
 457                 kfree_rcu(peer, rcu);
 458         }
 459 }
 460
 461 /*
 462  * Make sure all peer records have been discarded.
 463  */
 464 void rxrpc_destroy_all_peers(struct rxrpc_net *rxnet)
 465 {
 466         struct rxrpc_peer *peer;
 467         int i;
 468
 469         for (i = 0; i < HASH_SIZE(rxnet->peer_hash); i++) {
 470                 if (hlist_empty(&rxnet->peer_hash[i]))
 471                         continue;
 472
 473                 hlist_for_each_entry(peer, &rxnet->peer_hash[i], hash_link) {
 474                         pr_err("Leaked peer %u {%u} %pISp\n",
 475                                peer->debug_id,
 476                                atomic_read(&peer->usage),
 477                                &peer->srx.transport);
 478                 }
 479         }
 480 }
 481
 482 /**
 483  * rxrpc_kernel_get_peer - Get the peer address of a call
 484  * @sock: The socket on which the call is in progress.
 485  * @call: The call to query
 486  * @_srx: Where to place the result
 487  *
 488  * Get the address of the remote peer in a call.
 489  */
 490 void rxrpc_kernel_get_peer(struct socket *sock, struct rxrpc_call *call,
 491                            struct sockaddr_rxrpc *_srx)
 492 {
 493         *_srx = call->peer->srx;
 494 }
 495 EXPORT_SYMBOL(rxrpc_kernel_get_peer);
 496
 497 /**
 498  * rxrpc_kernel_get_rtt - Get a call's peer RTT
 499  * @sock: The socket on which the call is in progress.
 500  * @call: The call to query
 501  *
 502  * Get the call's peer RTT.
 503  */
 504 u64 rxrpc_kernel_get_rtt(struct socket *sock, struct rxrpc_call *call)
 505 {
 506         return call->peer->rtt;
 507 }
 508 EXPORT_SYMBOL(rxrpc_kernel_get_rtt);