root/net/rxrpc/peer_object.c

DEFINITIONS

1. rxrpc_peer_hash_key
2. rxrpc_peer_cmp_key
3. __rxrpc_lookup_peer_rcu
4. rxrpc_lookup_peer_rcu
5. rxrpc_assess_MTU_size
6. rxrpc_alloc_peer
7. rxrpc_init_peer
8. rxrpc_create_peer
9. rxrpc_new_incoming_peer
10. rxrpc_lookup_peer
11. rxrpc_get_peer
12. rxrpc_get_peer_maybe
13. __rxrpc_put_peer
14. rxrpc_put_peer
15. rxrpc_put_peer_locked
16. rxrpc_destroy_all_peers
17. rxrpc_kernel_get_peer
18. rxrpc_kernel_get_srtt

   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 /*
 301  * Set up a new incoming peer.  There shouldn't be any other matching peers
 302  * since we've already done a search in the list from the non-reentrant context
 303  * (the data_ready handler) that is the only place we can add new peers.
 304  */
 305 void rxrpc_new_incoming_peer(struct rxrpc_sock *rx, struct rxrpc_local *local,
 306                              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(rx, 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_sock *rx,
 324                                      struct rxrpc_local *local,
 325                                      struct sockaddr_rxrpc *srx, gfp_t gfp)
 326 {
 327         struct rxrpc_peer *peer, *candidate;
 328         struct rxrpc_net *rxnet = local->rxnet;
 329         unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
 330 
 331         _enter("{%pISp}", &srx->transport);
 332 
 333         /* search the peer list first */
 334         rcu_read_lock();
 335         peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
 336         if (peer && !rxrpc_get_peer_maybe(peer))
 337                 peer = NULL;
 338         rcu_read_unlock();
 339 
 340         if (!peer) {
 341                 /* The peer is not yet present in hash - create a candidate
 342                  * for a new record and then redo the search.
 343                  */
 344                 candidate = rxrpc_create_peer(rx, local, srx, hash_key, gfp);
 345                 if (!candidate) {
 346                         _leave(" = NULL [nomem]");
 347                         return NULL;
 348                 }
 349 
 350                 spin_lock_bh(&rxnet->peer_hash_lock);
 351 
 352                 /* Need to check that we aren't racing with someone else */
 353                 peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
 354                 if (peer && !rxrpc_get_peer_maybe(peer))
 355                         peer = NULL;
 356                 if (!peer) {
 357                         hash_add_rcu(rxnet->peer_hash,
 358                                      &candidate->hash_link, hash_key);
 359                         list_add_tail(&candidate->keepalive_link,
 360                                       &rxnet->peer_keepalive_new);
 361                 }
 362 
 363                 spin_unlock_bh(&rxnet->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  * Get a ref on a peer record.
 379  */
 380 struct rxrpc_peer *rxrpc_get_peer(struct rxrpc_peer *peer)
 381 {
 382         const void *here = __builtin_return_address(0);
 383         int n;
 384 
 385         n = atomic_inc_return(&peer->usage);
 386         trace_rxrpc_peer(peer->debug_id, rxrpc_peer_got, n, here);
 387         return peer;
 388 }
 389 
 390 /*
 391  * Get a ref on a peer record unless its usage has already reached 0.
 392  */
 393 struct rxrpc_peer *rxrpc_get_peer_maybe(struct rxrpc_peer *peer)
 394 {
 395         const void *here = __builtin_return_address(0);
 396 
 397         if (peer) {
 398                 int n = atomic_fetch_add_unless(&peer->usage, 1, 0);
 399                 if (n > 0)
 400                         trace_rxrpc_peer(peer->debug_id, rxrpc_peer_got, n + 1, here);
 401                 else
 402                         peer = NULL;
 403         }
 404         return peer;
 405 }
 406 
 407 /*
 408  * Discard a peer record.
 409  */
 410 static void __rxrpc_put_peer(struct rxrpc_peer *peer)
 411 {
 412         struct rxrpc_net *rxnet = peer->local->rxnet;
 413 
 414         ASSERT(hlist_empty(&peer->error_targets));
 415 
 416         spin_lock_bh(&rxnet->peer_hash_lock);
 417         hash_del_rcu(&peer->hash_link);
 418         list_del_init(&peer->keepalive_link);
 419         spin_unlock_bh(&rxnet->peer_hash_lock);
 420 
 421         rxrpc_put_local(peer->local);
 422         kfree_rcu(peer, rcu);
 423 }
 424 
 425 /*
 426  * Drop a ref on a peer record.
 427  */
 428 void rxrpc_put_peer(struct rxrpc_peer *peer)
 429 {
 430         const void *here = __builtin_return_address(0);
 431         unsigned int debug_id;
 432         int n;
 433 
 434         if (peer) {
 435                 debug_id = peer->debug_id;
 436                 n = atomic_dec_return(&peer->usage);
 437                 trace_rxrpc_peer(debug_id, rxrpc_peer_put, n, here);
 438                 if (n == 0)
 439                         __rxrpc_put_peer(peer);
 440         }
 441 }
 442 
 443 /*
 444  * Drop a ref on a peer record where the caller already holds the
 445  * peer_hash_lock.
 446  */
 447 void rxrpc_put_peer_locked(struct rxrpc_peer *peer)
 448 {
 449         const void *here = __builtin_return_address(0);
 450         unsigned int debug_id = peer->debug_id;
 451         int n;
 452 
 453         n = atomic_dec_return(&peer->usage);
 454         trace_rxrpc_peer(debug_id, rxrpc_peer_put, n, here);
 455         if (n == 0) {
 456                 hash_del_rcu(&peer->hash_link);
 457                 list_del_init(&peer->keepalive_link);
 458                 rxrpc_put_local(peer->local);
 459                 kfree_rcu(peer, rcu);
 460         }
 461 }
 462 
 463 /*
 464  * Make sure all peer records have been discarded.
 465  */
 466 void rxrpc_destroy_all_peers(struct rxrpc_net *rxnet)
 467 {
 468         struct rxrpc_peer *peer;
 469         int i;
 470 
 471         for (i = 0; i < HASH_SIZE(rxnet->peer_hash); i++) {
 472                 if (hlist_empty(&rxnet->peer_hash[i]))
 473                         continue;
 474 
 475                 hlist_for_each_entry(peer, &rxnet->peer_hash[i], hash_link) {
 476                         pr_err("Leaked peer %u {%u} %pISp\n",
 477                                peer->debug_id,
 478                                atomic_read(&peer->usage),
 479                                &peer->srx.transport);
 480                 }
 481         }
 482 }
 483 
 484 /**
 485  * rxrpc_kernel_get_peer - Get the peer address of a call
 486  * @sock: The socket on which the call is in progress.
 487  * @call: The call to query
 488  * @_srx: Where to place the result
 489  *
 490  * Get the address of the remote peer in a call.
 491  */
 492 void rxrpc_kernel_get_peer(struct socket *sock, struct rxrpc_call *call,
 493                            struct sockaddr_rxrpc *_srx)
 494 {
 495         *_srx = call->peer->srx;
 496 }
 497 EXPORT_SYMBOL(rxrpc_kernel_get_peer);
 498 
 499 /**
 500  * rxrpc_kernel_get_srtt - Get a call's peer smoothed RTT
 501  * @sock: The socket on which the call is in progress.
 502  * @call: The call to query
 503  *
 504  * Get the call's peer smoothed RTT.
 505  */
 506 u32 rxrpc_kernel_get_srtt(struct socket *sock, struct rxrpc_call *call)
 507 {
 508         return call->peer->srtt_us >> 3;
 509 }
 510 EXPORT_SYMBOL(rxrpc_kernel_get_srtt);