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                     refcount_read(&peer->ref) > 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, refcount_read(&peer->ref));
 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         const void *here = __builtin_return_address(0);
 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);
 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                 if (RXRPC_TX_SMSS > 2190)
 231                         peer->cong_cwnd = 2;
 232                 else if (RXRPC_TX_SMSS > 1095)
 233                         peer->cong_cwnd = 3;
 234                 else
 235                         peer->cong_cwnd = 4;
 236                 trace_rxrpc_peer(peer->debug_id, rxrpc_peer_new, 1, here);
 237         }
 238
 239         _leave(" = %p", peer);
 240         return peer;
 241 }
 242
 243 /*
 244  * Initialise peer record.
 245  */
 246 static void rxrpc_init_peer(struct rxrpc_sock *rx, struct rxrpc_peer *peer,
 247                             unsigned long hash_key)
 248 {
 249         peer->hash_key = hash_key;
 250         rxrpc_assess_MTU_size(rx, peer);
 251         peer->mtu = peer->if_mtu;
 252         peer->rtt_last_req = ktime_get_real();
 253
 254         switch (peer->srx.transport.family) {
 255         case AF_INET:
 256                 peer->hdrsize = sizeof(struct iphdr);
 257                 break;
 258 #ifdef CONFIG_AF_RXRPC_IPV6
 259         case AF_INET6:
 260                 peer->hdrsize = sizeof(struct ipv6hdr);
 261                 break;
 262 #endif
 263         default:
 264                 BUG();
 265         }
 266
 267         switch (peer->srx.transport_type) {
 268         case SOCK_DGRAM:
 269                 peer->hdrsize += sizeof(struct udphdr);
 270                 break;
 271         default:
 272                 BUG();
 273         }
 274
 275         peer->hdrsize += sizeof(struct rxrpc_wire_header);
 276         peer->maxdata = peer->mtu - peer->hdrsize;
 277 }
 278
 279 /*
 280  * Set up a new peer.
 281  */
 282 static struct rxrpc_peer *rxrpc_create_peer(struct rxrpc_sock *rx,
 283                                             struct rxrpc_local *local,
 284                                             struct sockaddr_rxrpc *srx,
 285                                             unsigned long hash_key,
 286                                             gfp_t gfp)
 287 {
 288         struct rxrpc_peer *peer;
 289
 290         _enter("");
 291
 292         peer = rxrpc_alloc_peer(local, gfp);
 293         if (peer) {
 294                 memcpy(&peer->srx, srx, sizeof(*srx));
 295                 rxrpc_init_peer(rx, peer, hash_key);
 296         }
 297
 298         _leave(" = %p", peer);
 299         return peer;
 300 }
 301
 302 static void rxrpc_free_peer(struct rxrpc_peer *peer)
 303 {
 304         rxrpc_put_local(peer->local);
 305         kfree_rcu(peer, rcu);
 306 }
 307
 308 /*
 309  * Set up a new incoming peer.  There shouldn't be any other matching peers
 310  * since we've already done a search in the list from the non-reentrant context
 311  * (the data_ready handler) that is the only place we can add new peers.
 312  */
 313 void rxrpc_new_incoming_peer(struct rxrpc_sock *rx, struct rxrpc_local *local,
 314                              struct rxrpc_peer *peer)
 315 {
 316         struct rxrpc_net *rxnet = local->rxnet;
 317         unsigned long hash_key;
 318
 319         hash_key = rxrpc_peer_hash_key(local, &peer->srx);
 320         rxrpc_init_peer(rx, peer, hash_key);
 321
 322         spin_lock(&rxnet->peer_hash_lock);
 323         hash_add_rcu(rxnet->peer_hash, &peer->hash_link, hash_key);
 324         list_add_tail(&peer->keepalive_link, &rxnet->peer_keepalive_new);
 325         spin_unlock(&rxnet->peer_hash_lock);
 326 }
 327
 328 /*
 329  * obtain a remote transport endpoint for the specified address
 330  */
 331 struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_sock *rx,
 332                                      struct rxrpc_local *local,
 333                                      struct sockaddr_rxrpc *srx, gfp_t gfp)
 334 {
 335         struct rxrpc_peer *peer, *candidate;
 336         struct rxrpc_net *rxnet = local->rxnet;
 337         unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
 338
 339         _enter("{%pISp}", &srx->transport);
 340
 341         /* search the peer list first */
 342         rcu_read_lock();
 343         peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
 344         if (peer && !rxrpc_get_peer_maybe(peer))
 345                 peer = NULL;
 346         rcu_read_unlock();
 347
 348         if (!peer) {
 349                 /* The peer is not yet present in hash - create a candidate
 350                  * for a new record and then redo the search.
 351                  */
 352                 candidate = rxrpc_create_peer(rx, local, srx, hash_key, gfp);
 353                 if (!candidate) {
 354                         _leave(" = NULL [nomem]");
 355                         return NULL;
 356                 }
 357
 358                 spin_lock_bh(&rxnet->peer_hash_lock);
 359
 360                 /* Need to check that we aren't racing with someone else */
 361                 peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
 362                 if (peer && !rxrpc_get_peer_maybe(peer))
 363                         peer = NULL;
 364                 if (!peer) {
 365                         hash_add_rcu(rxnet->peer_hash,
 366                                      &candidate->hash_link, hash_key);
 367                         list_add_tail(&candidate->keepalive_link,
 368                                       &rxnet->peer_keepalive_new);
 369                 }
 370
 371                 spin_unlock_bh(&rxnet->peer_hash_lock);
 372
 373                 if (peer)
 374                         rxrpc_free_peer(candidate);
 375                 else
 376                         peer = candidate;
 377         }
 378
 379         _net("PEER %d {%pISp}", peer->debug_id, &peer->srx.transport);
 380
 381         _leave(" = %p {u=%d}", peer, refcount_read(&peer->ref));
 382         return peer;
 383 }
 384
 385 /*
 386  * Get a ref on a peer record.
 387  */
 388 struct rxrpc_peer *rxrpc_get_peer(struct rxrpc_peer *peer)
 389 {
 390         const void *here = __builtin_return_address(0);
 391         int r;
 392
 393         __refcount_inc(&peer->ref, &r);
 394         trace_rxrpc_peer(peer->debug_id, rxrpc_peer_got, r + 1, here);
 395         return peer;
 396 }
 397
 398 /*
 399  * Get a ref on a peer record unless its usage has already reached 0.
 400  */
 401 struct rxrpc_peer *rxrpc_get_peer_maybe(struct rxrpc_peer *peer)
 402 {
 403         const void *here = __builtin_return_address(0);
 404         int r;
 405
 406         if (peer) {
 407                 if (__refcount_inc_not_zero(&peer->ref, &r))
 408                         trace_rxrpc_peer(peer->debug_id, rxrpc_peer_got, r + 1, here);
 409                 else
 410                         peer = NULL;
 411         }
 412         return peer;
 413 }
 414
 415 /*
 416  * Discard a peer record.
 417  */
 418 static void __rxrpc_put_peer(struct rxrpc_peer *peer)
 419 {
 420         struct rxrpc_net *rxnet = peer->local->rxnet;
 421
 422         ASSERT(hlist_empty(&peer->error_targets));
 423
 424         spin_lock_bh(&rxnet->peer_hash_lock);
 425         hash_del_rcu(&peer->hash_link);
 426         list_del_init(&peer->keepalive_link);
 427         spin_unlock_bh(&rxnet->peer_hash_lock);
 428
 429         rxrpc_free_peer(peer);
 430 }
 431
 432 /*
 433  * Drop a ref on a peer record.
 434  */
 435 void rxrpc_put_peer(struct rxrpc_peer *peer)
 436 {
 437         const void *here = __builtin_return_address(0);
 438         unsigned int debug_id;
 439         bool dead;
 440         int r;
 441
 442         if (peer) {
 443                 debug_id = peer->debug_id;
 444                 dead = __refcount_dec_and_test(&peer->ref, &r);
 445                 trace_rxrpc_peer(debug_id, rxrpc_peer_put, r - 1, here);
 446                 if (dead)
 447                         __rxrpc_put_peer(peer);
 448         }
 449 }
 450
 451 /*
 452  * Drop a ref on a peer record where the caller already holds the
 453  * peer_hash_lock.
 454  */
 455 void rxrpc_put_peer_locked(struct rxrpc_peer *peer)
 456 {
 457         const void *here = __builtin_return_address(0);
 458         unsigned int debug_id = peer->debug_id;
 459         bool dead;
 460         int r;
 461
 462         dead = __refcount_dec_and_test(&peer->ref, &r);
 463         trace_rxrpc_peer(debug_id, rxrpc_peer_put, r - 1, here);
 464         if (dead) {
 465                 hash_del_rcu(&peer->hash_link);
 466                 list_del_init(&peer->keepalive_link);
 467                 rxrpc_free_peer(peer);
 468         }
 469 }
 470
 471 /*
 472  * Make sure all peer records have been discarded.
 473  */
 474 void rxrpc_destroy_all_peers(struct rxrpc_net *rxnet)
 475 {
 476         struct rxrpc_peer *peer;
 477         int i;
 478
 479         for (i = 0; i < HASH_SIZE(rxnet->peer_hash); i++) {
 480                 if (hlist_empty(&rxnet->peer_hash[i]))
 481                         continue;
 482
 483                 hlist_for_each_entry(peer, &rxnet->peer_hash[i], hash_link) {
 484                         pr_err("Leaked peer %u {%u} %pISp\n",
 485                                peer->debug_id,
 486                                refcount_read(&peer->ref),
 487                                &peer->srx.transport);
 488                 }
 489         }
 490 }
 491
 492 /**
 493  * rxrpc_kernel_get_peer - Get the peer address of a call
 494  * @sock: The socket on which the call is in progress.
 495  * @call: The call to query
 496  * @_srx: Where to place the result
 497  *
 498  * Get the address of the remote peer in a call.
 499  */
 500 void rxrpc_kernel_get_peer(struct socket *sock, struct rxrpc_call *call,
 501                            struct sockaddr_rxrpc *_srx)
 502 {
 503         *_srx = call->peer->srx;
 504 }
 505 EXPORT_SYMBOL(rxrpc_kernel_get_peer);
 506
 507 /**
 508  * rxrpc_kernel_get_srtt - Get a call's peer smoothed RTT
 509  * @sock: The socket on which the call is in progress.
 510  * @call: The call to query
 511  * @_srtt: Where to store the SRTT value.
 512  *
 513  * Get the call's peer smoothed RTT in uS.
 514  */
 515 bool rxrpc_kernel_get_srtt(struct socket *sock, struct rxrpc_call *call,
 516                            u32 *_srtt)
 517 {
 518         struct rxrpc_peer *peer = call->peer;
 519
 520         if (peer->rtt_count == 0) {
 521                 *_srtt = 1000000; /* 1S */
 522                 return false;
 523         }
 524
 525         *_srtt = call->peer->srtt_us >> 3;
 526         return true;
 527 }
 528 EXPORT_SYMBOL(rxrpc_kernel_get_srtt);