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 static const struct sockaddr_rxrpc rxrpc_null_addr;
  26
  27 /*
  28  * Hash a peer key.
  29  */
  30 static unsigned long rxrpc_peer_hash_key(struct rxrpc_local *local,
  31                                          const struct sockaddr_rxrpc *srx)
  32 {
  33         const u16 *p;
  34         unsigned int i, size;
  35         unsigned long hash_key;
  36
  37         _enter("");
  38
  39         hash_key = (unsigned long)local / __alignof__(*local);
  40         hash_key += srx->transport_type;
  41         hash_key += srx->transport_len;
  42         hash_key += srx->transport.family;
  43
  44         switch (srx->transport.family) {
  45         case AF_INET:
  46                 hash_key += (u16 __force)srx->transport.sin.sin_port;
  47                 size = sizeof(srx->transport.sin.sin_addr);
  48                 p = (u16 *)&srx->transport.sin.sin_addr;
  49                 break;
  50 #ifdef CONFIG_AF_RXRPC_IPV6
  51         case AF_INET6:
  52                 hash_key += (u16 __force)srx->transport.sin.sin_port;
  53                 size = sizeof(srx->transport.sin6.sin6_addr);
  54                 p = (u16 *)&srx->transport.sin6.sin6_addr;
  55                 break;
  56 #endif
  57         default:
  58                 WARN(1, "AF_RXRPC: Unsupported transport address family\n");
  59                 return 0;
  60         }
  61
  62         /* Step through the peer address in 16-bit portions for speed */
  63         for (i = 0; i < size; i += sizeof(*p), p++)
  64                 hash_key += *p;
  65
  66         _leave(" 0x%lx", hash_key);
  67         return hash_key;
  68 }
  69
  70 /*
  71  * Compare a peer to a key.  Return -ve, 0 or +ve to indicate less than, same
  72  * or greater than.
  73  *
  74  * Unfortunately, the primitives in linux/hashtable.h don't allow for sorted
  75  * buckets and mid-bucket insertion, so we don't make full use of this
  76  * information at this point.
  77  */
  78 static long rxrpc_peer_cmp_key(const struct rxrpc_peer *peer,
  79                                struct rxrpc_local *local,
  80                                const struct sockaddr_rxrpc *srx,
  81                                unsigned long hash_key)
  82 {
  83         long diff;
  84
  85         diff = ((peer->hash_key - hash_key) ?:
  86                 ((unsigned long)peer->local - (unsigned long)local) ?:
  87                 (peer->srx.transport_type - srx->transport_type) ?:
  88                 (peer->srx.transport_len - srx->transport_len) ?:
  89                 (peer->srx.transport.family - srx->transport.family));
  90         if (diff != 0)
  91                 return diff;
  92
  93         switch (srx->transport.family) {
  94         case AF_INET:
  95                 return ((u16 __force)peer->srx.transport.sin.sin_port -
  96                         (u16 __force)srx->transport.sin.sin_port) ?:
  97                         memcmp(&peer->srx.transport.sin.sin_addr,
  98                                &srx->transport.sin.sin_addr,
  99                                sizeof(struct in_addr));
 100 #ifdef CONFIG_AF_RXRPC_IPV6
 101         case AF_INET6:
 102                 return ((u16 __force)peer->srx.transport.sin6.sin6_port -
 103                         (u16 __force)srx->transport.sin6.sin6_port) ?:
 104                         memcmp(&peer->srx.transport.sin6.sin6_addr,
 105                                &srx->transport.sin6.sin6_addr,
 106                                sizeof(struct in6_addr));
 107 #endif
 108         default:
 109                 BUG();
 110         }
 111 }
 112
 113 /*
 114  * Look up a remote transport endpoint for the specified address using RCU.
 115  */
 116 static struct rxrpc_peer *__rxrpc_lookup_peer_rcu(
 117         struct rxrpc_local *local,
 118         const struct sockaddr_rxrpc *srx,
 119         unsigned long hash_key)
 120 {
 121         struct rxrpc_peer *peer;
 122         struct rxrpc_net *rxnet = local->rxnet;
 123
 124         hash_for_each_possible_rcu(rxnet->peer_hash, peer, hash_link, hash_key) {
 125                 if (rxrpc_peer_cmp_key(peer, local, srx, hash_key) == 0 &&
 126                     refcount_read(&peer->ref) > 0)
 127                         return peer;
 128         }
 129
 130         return NULL;
 131 }
 132
 133 /*
 134  * Look up a remote transport endpoint for the specified address using RCU.
 135  */
 136 struct rxrpc_peer *rxrpc_lookup_peer_rcu(struct rxrpc_local *local,
 137                                          const struct sockaddr_rxrpc *srx)
 138 {
 139         struct rxrpc_peer *peer;
 140         unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
 141
 142         peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
 143         if (peer)
 144                 _leave(" = %p {u=%d}", peer, refcount_read(&peer->ref));
 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_local *local,
 153                                   struct rxrpc_peer *peer)
 154 {
 155         struct net *net = local->net;
 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                                     enum rxrpc_peer_trace why)
 212 {
 213         struct rxrpc_peer *peer;
 214
 215         _enter("");
 216
 217         peer = kzalloc(sizeof(struct rxrpc_peer), gfp);
 218         if (peer) {
 219                 refcount_set(&peer->ref, 1);
 220                 peer->local = rxrpc_get_local(local, rxrpc_local_get_peer);
 221                 INIT_HLIST_HEAD(&peer->error_targets);
 222                 peer->service_conns = RB_ROOT;
 223                 seqlock_init(&peer->service_conn_lock);
 224                 spin_lock_init(&peer->lock);
 225                 spin_lock_init(&peer->rtt_input_lock);
 226                 peer->debug_id = atomic_inc_return(&rxrpc_debug_id);
 227
 228                 rxrpc_peer_init_rtt(peer);
 229
 230                 peer->cong_ssthresh = RXRPC_TX_MAX_WINDOW;
 231                 trace_rxrpc_peer(peer->debug_id, 1, why);
 232         }
 233
 234         _leave(" = %p", peer);
 235         return peer;
 236 }
 237
 238 /*
 239  * Initialise peer record.
 240  */
 241 static void rxrpc_init_peer(struct rxrpc_local *local, struct rxrpc_peer *peer,
 242                             unsigned long hash_key)
 243 {
 244         peer->hash_key = hash_key;
 245         rxrpc_assess_MTU_size(local, 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, rxrpc_peer_new_client);
 287         if (peer) {
 288                 memcpy(&peer->srx, srx, sizeof(*srx));
 289                 rxrpc_init_peer(local, peer, hash_key);
 290         }
 291
 292         _leave(" = %p", peer);
 293         return peer;
 294 }
 295
 296 static void rxrpc_free_peer(struct rxrpc_peer *peer)
 297 {
 298         trace_rxrpc_peer(peer->debug_id, 0, rxrpc_peer_free);
 299         rxrpc_put_local(peer->local, rxrpc_local_put_peer);
 300         kfree_rcu(peer, rcu);
 301 }
 302
 303 /*
 304  * Set up a new incoming peer.  There shouldn't be any other matching peers
 305  * since we've already done a search in the list from the non-reentrant context
 306  * (the data_ready handler) that is the only place we can add new peers.
 307  */
 308 void rxrpc_new_incoming_peer(struct rxrpc_local *local, struct rxrpc_peer *peer)
 309 {
 310         struct rxrpc_net *rxnet = local->rxnet;
 311         unsigned long hash_key;
 312
 313         hash_key = rxrpc_peer_hash_key(local, &peer->srx);
 314         rxrpc_init_peer(local, peer, hash_key);
 315
 316         spin_lock(&rxnet->peer_hash_lock);
 317         hash_add_rcu(rxnet->peer_hash, &peer->hash_link, hash_key);
 318         list_add_tail(&peer->keepalive_link, &rxnet->peer_keepalive_new);
 319         spin_unlock(&rxnet->peer_hash_lock);
 320 }
 321
 322 /*
 323  * obtain a remote transport endpoint for the specified address
 324  */
 325 struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_local *local,
 326                                      struct sockaddr_rxrpc *srx, gfp_t gfp)
 327 {
 328         struct rxrpc_peer *peer, *candidate;
 329         struct rxrpc_net *rxnet = local->rxnet;
 330         unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
 331
 332         _enter("{%pISp}", &srx->transport);
 333
 334         /* search the peer list first */
 335         rcu_read_lock();
 336         peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
 337         if (peer && !rxrpc_get_peer_maybe(peer, rxrpc_peer_get_lookup_client))
 338                 peer = NULL;
 339         rcu_read_unlock();
 340
 341         if (!peer) {
 342                 /* The peer is not yet present in hash - create a candidate
 343                  * for a new record and then redo the search.
 344                  */
 345                 candidate = rxrpc_create_peer(local, srx, hash_key, gfp);
 346                 if (!candidate) {
 347                         _leave(" = NULL [nomem]");
 348                         return NULL;
 349                 }
 350
 351                 spin_lock(&rxnet->peer_hash_lock);
 352
 353                 /* Need to check that we aren't racing with someone else */
 354                 peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
 355                 if (peer && !rxrpc_get_peer_maybe(peer, rxrpc_peer_get_lookup_client))
 356                         peer = NULL;
 357                 if (!peer) {
 358                         hash_add_rcu(rxnet->peer_hash,
 359                                      &candidate->hash_link, hash_key);
 360                         list_add_tail(&candidate->keepalive_link,
 361                                       &rxnet->peer_keepalive_new);
 362                 }
 363
 364                 spin_unlock(&rxnet->peer_hash_lock);
 365
 366                 if (peer)
 367                         rxrpc_free_peer(candidate);
 368                 else
 369                         peer = candidate;
 370         }
 371
 372         _leave(" = %p {u=%d}", peer, refcount_read(&peer->ref));
 373         return peer;
 374 }
 375
 376 /*
 377  * Get a ref on a peer record.
 378  */
 379 struct rxrpc_peer *rxrpc_get_peer(struct rxrpc_peer *peer, enum rxrpc_peer_trace why)
 380 {
 381         int r;
 382
 383         __refcount_inc(&peer->ref, &r);
 384         trace_rxrpc_peer(peer->debug_id, r + 1, why);
 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                                         enum rxrpc_peer_trace why)
 393 {
 394         int r;
 395
 396         if (peer) {
 397                 if (__refcount_inc_not_zero(&peer->ref, &r))
 398                         trace_rxrpc_peer(peer->debug_id, r + 1, why);
 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(&rxnet->peer_hash_lock);
 415         hash_del_rcu(&peer->hash_link);
 416         list_del_init(&peer->keepalive_link);
 417         spin_unlock(&rxnet->peer_hash_lock);
 418
 419         rxrpc_free_peer(peer);
 420 }
 421
 422 /*
 423  * Drop a ref on a peer record.
 424  */
 425 void rxrpc_put_peer(struct rxrpc_peer *peer, enum rxrpc_peer_trace why)
 426 {
 427         unsigned int debug_id;
 428         bool dead;
 429         int r;
 430
 431         if (peer) {
 432                 debug_id = peer->debug_id;
 433                 dead = __refcount_dec_and_test(&peer->ref, &r);
 434                 trace_rxrpc_peer(debug_id, r - 1, why);
 435                 if (dead)
 436                         __rxrpc_put_peer(peer);
 437         }
 438 }
 439
 440 /*
 441  * Make sure all peer records have been discarded.
 442  */
 443 void rxrpc_destroy_all_peers(struct rxrpc_net *rxnet)
 444 {
 445         struct rxrpc_peer *peer;
 446         int i;
 447
 448         for (i = 0; i < HASH_SIZE(rxnet->peer_hash); i++) {
 449                 if (hlist_empty(&rxnet->peer_hash[i]))
 450                         continue;
 451
 452                 hlist_for_each_entry(peer, &rxnet->peer_hash[i], hash_link) {
 453                         pr_err("Leaked peer %u {%u} %pISp\n",
 454                                peer->debug_id,
 455                                refcount_read(&peer->ref),
 456                                &peer->srx.transport);
 457                 }
 458         }
 459 }
 460
 461 /**
 462  * rxrpc_kernel_get_call_peer - Get the peer address of a call
 463  * @sock: The socket on which the call is in progress.
 464  * @call: The call to query
 465  *
 466  * Get a record for the remote peer in a call.
 467  */
 468 struct rxrpc_peer *rxrpc_kernel_get_call_peer(struct socket *sock, struct rxrpc_call *call)
 469 {
 470         return call->peer;
 471 }
 472 EXPORT_SYMBOL(rxrpc_kernel_get_call_peer);
 473
 474 /**
 475  * rxrpc_kernel_get_srtt - Get a call's peer smoothed RTT
 476  * @peer: The peer to query
 477  *
 478  * Get the call's peer smoothed RTT in uS or UINT_MAX if we have no samples.
 479  */
 480 unsigned int rxrpc_kernel_get_srtt(const struct rxrpc_peer *peer)
 481 {
 482         return peer->rtt_count > 0 ? peer->srtt_us >> 3 : UINT_MAX;
 483 }
 484 EXPORT_SYMBOL(rxrpc_kernel_get_srtt);
 485
 486 /**
 487  * rxrpc_kernel_remote_srx - Get the address of a peer
 488  * @peer: The peer to query
 489  *
 490  * Get a pointer to the address from a peer record.  The caller is responsible
 491  * for making sure that the address is not deallocated.
 492  */
 493 const struct sockaddr_rxrpc *rxrpc_kernel_remote_srx(const struct rxrpc_peer *peer)
 494 {
 495         return peer ? &peer->srx : &rxrpc_null_addr;
 496 }
 497 EXPORT_SYMBOL(rxrpc_kernel_remote_srx);
 498
 499 /**
 500  * rxrpc_kernel_remote_addr - Get the peer transport address of a call
 501  * @peer: The peer to query
 502  *
 503  * Get a pointer to the transport address from a peer record.  The caller is
 504  * responsible for making sure that the address is not deallocated.
 505  */
 506 const struct sockaddr *rxrpc_kernel_remote_addr(const struct rxrpc_peer *peer)
 507 {
 508         return (const struct sockaddr *)
 509                 (peer ? &peer->srx.transport : &rxrpc_null_addr.transport);
 510 }
 511 EXPORT_SYMBOL(rxrpc_kernel_remote_addr);