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                 rxrpc_peer_init_rtt(peer);
 228
 229                 if (RXRPC_TX_SMSS > 2190)
 230                         peer->cong_cwnd = 2;
 231                 else if (RXRPC_TX_SMSS > 1095)
 232                         peer->cong_cwnd = 3;
 233                 else
 234                         peer->cong_cwnd = 4;
 235         }
 236
 237         _leave(" = %p", peer);
 238         return peer;
 239 }
 240
 241 /*
 242  * Initialise peer record.
 243  */
 244 static void rxrpc_init_peer(struct rxrpc_sock *rx, struct rxrpc_peer *peer,
 245                             unsigned long hash_key)
 246 {
 247         peer->hash_key = hash_key;
 248         rxrpc_assess_MTU_size(rx, peer);
 249         peer->mtu = peer->if_mtu;
 250         peer->rtt_last_req = ktime_get_real();
 251
 252         switch (peer->srx.transport.family) {
 253         case AF_INET:
 254                 peer->hdrsize = sizeof(struct iphdr);
 255                 break;
 256 #ifdef CONFIG_AF_RXRPC_IPV6
 257         case AF_INET6:
 258                 peer->hdrsize = sizeof(struct ipv6hdr);
 259                 break;
 260 #endif
 261         default:
 262                 BUG();
 263         }
 264
 265         switch (peer->srx.transport_type) {
 266         case SOCK_DGRAM:
 267                 peer->hdrsize += sizeof(struct udphdr);
 268                 break;
 269         default:
 270                 BUG();
 271         }
 272
 273         peer->hdrsize += sizeof(struct rxrpc_wire_header);
 274         peer->maxdata = peer->mtu - peer->hdrsize;
 275 }
 276
 277 /*
 278  * Set up a new peer.
 279  */
 280 static struct rxrpc_peer *rxrpc_create_peer(struct rxrpc_sock *rx,
 281                                             struct rxrpc_local *local,
 282                                             struct sockaddr_rxrpc *srx,
 283                                             unsigned long hash_key,
 284                                             gfp_t gfp)
 285 {
 286         struct rxrpc_peer *peer;
 287
 288         _enter("");
 289
 290         peer = rxrpc_alloc_peer(local, gfp);
 291         if (peer) {
 292                 memcpy(&peer->srx, srx, sizeof(*srx));
 293                 rxrpc_init_peer(rx, peer, hash_key);
 294         }
 295
 296         _leave(" = %p", peer);
 297         return peer;
 298 }
 299
 300 static void rxrpc_free_peer(struct rxrpc_peer *peer)
 301 {
 302         rxrpc_put_local(peer->local);
 303         kfree_rcu(peer, rcu);
 304 }
 305
 306 /*
 307  * Set up a new incoming peer.  There shouldn't be any other matching peers
 308  * since we've already done a search in the list from the non-reentrant context
 309  * (the data_ready handler) that is the only place we can add new peers.
 310  */
 311 void rxrpc_new_incoming_peer(struct rxrpc_sock *rx, struct rxrpc_local *local,
 312                              struct rxrpc_peer *peer)
 313 {
 314         struct rxrpc_net *rxnet = local->rxnet;
 315         unsigned long hash_key;
 316
 317         hash_key = rxrpc_peer_hash_key(local, &peer->srx);
 318         rxrpc_init_peer(rx, peer, hash_key);
 319
 320         spin_lock(&rxnet->peer_hash_lock);
 321         hash_add_rcu(rxnet->peer_hash, &peer->hash_link, hash_key);
 322         list_add_tail(&peer->keepalive_link, &rxnet->peer_keepalive_new);
 323         spin_unlock(&rxnet->peer_hash_lock);
 324 }
 325
 326 /*
 327  * obtain a remote transport endpoint for the specified address
 328  */
 329 struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_sock *rx,
 330                                      struct rxrpc_local *local,
 331                                      struct sockaddr_rxrpc *srx, gfp_t gfp)
 332 {
 333         struct rxrpc_peer *peer, *candidate;
 334         struct rxrpc_net *rxnet = local->rxnet;
 335         unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
 336
 337         _enter("{%pISp}", &srx->transport);
 338
 339         /* search the peer list first */
 340         rcu_read_lock();
 341         peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
 342         if (peer && !rxrpc_get_peer_maybe(peer))
 343                 peer = NULL;
 344         rcu_read_unlock();
 345
 346         if (!peer) {
 347                 /* The peer is not yet present in hash - create a candidate
 348                  * for a new record and then redo the search.
 349                  */
 350                 candidate = rxrpc_create_peer(rx, local, srx, hash_key, gfp);
 351                 if (!candidate) {
 352                         _leave(" = NULL [nomem]");
 353                         return NULL;
 354                 }
 355
 356                 spin_lock_bh(&rxnet->peer_hash_lock);
 357
 358                 /* Need to check that we aren't racing with someone else */
 359                 peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
 360                 if (peer && !rxrpc_get_peer_maybe(peer))
 361                         peer = NULL;
 362                 if (!peer) {
 363                         hash_add_rcu(rxnet->peer_hash,
 364                                      &candidate->hash_link, hash_key);
 365                         list_add_tail(&candidate->keepalive_link,
 366                                       &rxnet->peer_keepalive_new);
 367                 }
 368
 369                 spin_unlock_bh(&rxnet->peer_hash_lock);
 370
 371                 if (peer)
 372                         rxrpc_free_peer(candidate);
 373                 else
 374                         peer = candidate;
 375         }
 376
 377         _net("PEER %d {%pISp}", peer->debug_id, &peer->srx.transport);
 378
 379         _leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
 380         return peer;
 381 }
 382
 383 /*
 384  * Get a ref on a peer record.
 385  */
 386 struct rxrpc_peer *rxrpc_get_peer(struct rxrpc_peer *peer)
 387 {
 388         const void *here = __builtin_return_address(0);
 389         int n;
 390
 391         n = atomic_inc_return(&peer->usage);
 392         trace_rxrpc_peer(peer->debug_id, rxrpc_peer_got, n, here);
 393         return peer;
 394 }
 395
 396 /*
 397  * Get a ref on a peer record unless its usage has already reached 0.
 398  */
 399 struct rxrpc_peer *rxrpc_get_peer_maybe(struct rxrpc_peer *peer)
 400 {
 401         const void *here = __builtin_return_address(0);
 402
 403         if (peer) {
 404                 int n = atomic_fetch_add_unless(&peer->usage, 1, 0);
 405                 if (n > 0)
 406                         trace_rxrpc_peer(peer->debug_id, rxrpc_peer_got, n + 1, here);
 407                 else
 408                         peer = NULL;
 409         }
 410         return peer;
 411 }
 412
 413 /*
 414  * Discard a peer record.
 415  */
 416 static void __rxrpc_put_peer(struct rxrpc_peer *peer)
 417 {
 418         struct rxrpc_net *rxnet = peer->local->rxnet;
 419
 420         ASSERT(hlist_empty(&peer->error_targets));
 421
 422         spin_lock_bh(&rxnet->peer_hash_lock);
 423         hash_del_rcu(&peer->hash_link);
 424         list_del_init(&peer->keepalive_link);
 425         spin_unlock_bh(&rxnet->peer_hash_lock);
 426
 427         rxrpc_free_peer(peer);
 428 }
 429
 430 /*
 431  * Drop a ref on a peer record.
 432  */
 433 void rxrpc_put_peer(struct rxrpc_peer *peer)
 434 {
 435         const void *here = __builtin_return_address(0);
 436         unsigned int debug_id;
 437         int n;
 438
 439         if (peer) {
 440                 debug_id = peer->debug_id;
 441                 n = atomic_dec_return(&peer->usage);
 442                 trace_rxrpc_peer(debug_id, rxrpc_peer_put, n, here);
 443                 if (n == 0)
 444                         __rxrpc_put_peer(peer);
 445         }
 446 }
 447
 448 /*
 449  * Drop a ref on a peer record where the caller already holds the
 450  * peer_hash_lock.
 451  */
 452 void rxrpc_put_peer_locked(struct rxrpc_peer *peer)
 453 {
 454         const void *here = __builtin_return_address(0);
 455         unsigned int debug_id = peer->debug_id;
 456         int n;
 457
 458         n = atomic_dec_return(&peer->usage);
 459         trace_rxrpc_peer(debug_id, rxrpc_peer_put, n, here);
 460         if (n == 0) {
 461                 hash_del_rcu(&peer->hash_link);
 462                 list_del_init(&peer->keepalive_link);
 463                 rxrpc_free_peer(peer);
 464         }
 465 }
 466
 467 /*
 468  * Make sure all peer records have been discarded.
 469  */
 470 void rxrpc_destroy_all_peers(struct rxrpc_net *rxnet)
 471 {
 472         struct rxrpc_peer *peer;
 473         int i;
 474
 475         for (i = 0; i < HASH_SIZE(rxnet->peer_hash); i++) {
 476                 if (hlist_empty(&rxnet->peer_hash[i]))
 477                         continue;
 478
 479                 hlist_for_each_entry(peer, &rxnet->peer_hash[i], hash_link) {
 480                         pr_err("Leaked peer %u {%u} %pISp\n",
 481                                peer->debug_id,
 482                                atomic_read(&peer->usage),
 483                                &peer->srx.transport);
 484                 }
 485         }
 486 }
 487
 488 /**
 489  * rxrpc_kernel_get_peer - Get the peer address of a call
 490  * @sock: The socket on which the call is in progress.
 491  * @call: The call to query
 492  * @_srx: Where to place the result
 493  *
 494  * Get the address of the remote peer in a call.
 495  */
 496 void rxrpc_kernel_get_peer(struct socket *sock, struct rxrpc_call *call,
 497                            struct sockaddr_rxrpc *_srx)
 498 {
 499         *_srx = call->peer->srx;
 500 }
 501 EXPORT_SYMBOL(rxrpc_kernel_get_peer);
 502
 503 /**
 504  * rxrpc_kernel_get_srtt - Get a call's peer smoothed RTT
 505  * @sock: The socket on which the call is in progress.
 506  * @call: The call to query
 507  * @_srtt: Where to store the SRTT value.
 508  *
 509  * Get the call's peer smoothed RTT in uS.
 510  */
 511 bool rxrpc_kernel_get_srtt(struct socket *sock, struct rxrpc_call *call,
 512                            u32 *_srtt)
 513 {
 514         struct rxrpc_peer *peer = call->peer;
 515
 516         if (peer->rtt_count == 0) {
 517                 *_srtt = 1000000; /* 1S */
 518                 return false;
 519         }
 520
 521         *_srtt = call->peer->srtt_us >> 3;
 522         return true;
 523 }
 524 EXPORT_SYMBOL(rxrpc_kernel_get_srtt);