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                 _leave(" = %p {u=%d}", peer, refcount_read(&peer->ref));
 143         return peer;
 144 }
 145
 146 /*
 147  * assess the MTU size for the network interface through which this peer is
 148  * reached
 149  */
 150 static void rxrpc_assess_MTU_size(struct rxrpc_local *local,
 151                                   struct rxrpc_peer *peer)
 152 {
 153         struct net *net = local->net;
 154         struct dst_entry *dst;
 155         struct rtable *rt;
 156         struct flowi fl;
 157         struct flowi4 *fl4 = &fl.u.ip4;
 158 #ifdef CONFIG_AF_RXRPC_IPV6
 159         struct flowi6 *fl6 = &fl.u.ip6;
 160 #endif
 161
 162         peer->if_mtu = 1500;
 163
 164         memset(&fl, 0, sizeof(fl));
 165         switch (peer->srx.transport.family) {
 166         case AF_INET:
 167                 rt = ip_route_output_ports(
 168                         net, fl4, NULL,
 169                         peer->srx.transport.sin.sin_addr.s_addr, 0,
 170                         htons(7000), htons(7001), IPPROTO_UDP, 0, 0);
 171                 if (IS_ERR(rt)) {
 172                         _leave(" [route err %ld]", PTR_ERR(rt));
 173                         return;
 174                 }
 175                 dst = &rt->dst;
 176                 break;
 177
 178 #ifdef CONFIG_AF_RXRPC_IPV6
 179         case AF_INET6:
 180                 fl6->flowi6_iif = LOOPBACK_IFINDEX;
 181                 fl6->flowi6_scope = RT_SCOPE_UNIVERSE;
 182                 fl6->flowi6_proto = IPPROTO_UDP;
 183                 memcpy(&fl6->daddr, &peer->srx.transport.sin6.sin6_addr,
 184                        sizeof(struct in6_addr));
 185                 fl6->fl6_dport = htons(7001);
 186                 fl6->fl6_sport = htons(7000);
 187                 dst = ip6_route_output(net, NULL, fl6);
 188                 if (dst->error) {
 189                         _leave(" [route err %d]", dst->error);
 190                         return;
 191                 }
 192                 break;
 193 #endif
 194
 195         default:
 196                 BUG();
 197         }
 198
 199         peer->if_mtu = dst_mtu(dst);
 200         dst_release(dst);
 201
 202         _leave(" [if_mtu %u]", peer->if_mtu);
 203 }
 204
 205 /*
 206  * Allocate a peer.
 207  */
 208 struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *local, gfp_t gfp,
 209                                     enum rxrpc_peer_trace why)
 210 {
 211         struct rxrpc_peer *peer;
 212
 213         _enter("");
 214
 215         peer = kzalloc(sizeof(struct rxrpc_peer), gfp);
 216         if (peer) {
 217                 refcount_set(&peer->ref, 1);
 218                 peer->local = rxrpc_get_local(local, rxrpc_local_get_peer);
 219                 INIT_HLIST_HEAD(&peer->error_targets);
 220                 peer->service_conns = RB_ROOT;
 221                 seqlock_init(&peer->service_conn_lock);
 222                 spin_lock_init(&peer->lock);
 223                 spin_lock_init(&peer->rtt_input_lock);
 224                 peer->debug_id = atomic_inc_return(&rxrpc_debug_id);
 225
 226                 rxrpc_peer_init_rtt(peer);
 227
 228                 peer->cong_ssthresh = RXRPC_TX_MAX_WINDOW;
 229                 trace_rxrpc_peer(peer->debug_id, 1, why);
 230         }
 231
 232         _leave(" = %p", peer);
 233         return peer;
 234 }
 235
 236 /*
 237  * Initialise peer record.
 238  */
 239 static void rxrpc_init_peer(struct rxrpc_local *local, struct rxrpc_peer *peer,
 240                             unsigned long hash_key)
 241 {
 242         peer->hash_key = hash_key;
 243         rxrpc_assess_MTU_size(local, peer);
 244         peer->mtu = peer->if_mtu;
 245         peer->rtt_last_req = ktime_get_real();
 246
 247         switch (peer->srx.transport.family) {
 248         case AF_INET:
 249                 peer->hdrsize = sizeof(struct iphdr);
 250                 break;
 251 #ifdef CONFIG_AF_RXRPC_IPV6
 252         case AF_INET6:
 253                 peer->hdrsize = sizeof(struct ipv6hdr);
 254                 break;
 255 #endif
 256         default:
 257                 BUG();
 258         }
 259
 260         switch (peer->srx.transport_type) {
 261         case SOCK_DGRAM:
 262                 peer->hdrsize += sizeof(struct udphdr);
 263                 break;
 264         default:
 265                 BUG();
 266         }
 267
 268         peer->hdrsize += sizeof(struct rxrpc_wire_header);
 269         peer->maxdata = peer->mtu - peer->hdrsize;
 270 }
 271
 272 /*
 273  * Set up a new peer.
 274  */
 275 static struct rxrpc_peer *rxrpc_create_peer(struct rxrpc_local *local,
 276                                             struct sockaddr_rxrpc *srx,
 277                                             unsigned long hash_key,
 278                                             gfp_t gfp)
 279 {
 280         struct rxrpc_peer *peer;
 281
 282         _enter("");
 283
 284         peer = rxrpc_alloc_peer(local, gfp, rxrpc_peer_new_client);
 285         if (peer) {
 286                 memcpy(&peer->srx, srx, sizeof(*srx));
 287                 rxrpc_init_peer(local, peer, hash_key);
 288         }
 289
 290         _leave(" = %p", peer);
 291         return peer;
 292 }
 293
 294 static void rxrpc_free_peer(struct rxrpc_peer *peer)
 295 {
 296         trace_rxrpc_peer(peer->debug_id, 0, rxrpc_peer_free);
 297         rxrpc_put_local(peer->local, rxrpc_local_put_peer);
 298         kfree_rcu(peer, rcu);
 299 }
 300
 301 /*
 302  * Set up a new incoming peer.  There shouldn't be any other matching peers
 303  * since we've already done a search in the list from the non-reentrant context
 304  * (the data_ready handler) that is the only place we can add new peers.
 305  */
 306 void rxrpc_new_incoming_peer(struct rxrpc_local *local, 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(local, 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_local *local,
 324                                      struct sockaddr_rxrpc *srx, gfp_t gfp)
 325 {
 326         struct rxrpc_peer *peer, *candidate;
 327         struct rxrpc_net *rxnet = local->rxnet;
 328         unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
 329
 330         _enter("{%pISp}", &srx->transport);
 331
 332         /* search the peer list first */
 333         rcu_read_lock();
 334         peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
 335         if (peer && !rxrpc_get_peer_maybe(peer, rxrpc_peer_get_lookup_client))
 336                 peer = NULL;
 337         rcu_read_unlock();
 338
 339         if (!peer) {
 340                 /* The peer is not yet present in hash - create a candidate
 341                  * for a new record and then redo the search.
 342                  */
 343                 candidate = rxrpc_create_peer(local, srx, hash_key, gfp);
 344                 if (!candidate) {
 345                         _leave(" = NULL [nomem]");
 346                         return NULL;
 347                 }
 348
 349                 spin_lock(&rxnet->peer_hash_lock);
 350
 351                 /* Need to check that we aren't racing with someone else */
 352                 peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
 353                 if (peer && !rxrpc_get_peer_maybe(peer, rxrpc_peer_get_lookup_client))
 354                         peer = NULL;
 355                 if (!peer) {
 356                         hash_add_rcu(rxnet->peer_hash,
 357                                      &candidate->hash_link, hash_key);
 358                         list_add_tail(&candidate->keepalive_link,
 359                                       &rxnet->peer_keepalive_new);
 360                 }
 361
 362                 spin_unlock(&rxnet->peer_hash_lock);
 363
 364                 if (peer)
 365                         rxrpc_free_peer(candidate);
 366                 else
 367                         peer = candidate;
 368         }
 369
 370         _leave(" = %p {u=%d}", peer, refcount_read(&peer->ref));
 371         return peer;
 372 }
 373
 374 /*
 375  * Get a ref on a peer record.
 376  */
 377 struct rxrpc_peer *rxrpc_get_peer(struct rxrpc_peer *peer, enum rxrpc_peer_trace why)
 378 {
 379         int r;
 380
 381         __refcount_inc(&peer->ref, &r);
 382         trace_rxrpc_peer(peer->debug_id, r + 1, why);
 383         return peer;
 384 }
 385
 386 /*
 387  * Get a ref on a peer record unless its usage has already reached 0.
 388  */
 389 struct rxrpc_peer *rxrpc_get_peer_maybe(struct rxrpc_peer *peer,
 390                                         enum rxrpc_peer_trace why)
 391 {
 392         int r;
 393
 394         if (peer) {
 395                 if (__refcount_inc_not_zero(&peer->ref, &r))
 396                         trace_rxrpc_peer(peer->debug_id, r + 1, why);
 397                 else
 398                         peer = NULL;
 399         }
 400         return peer;
 401 }
 402
 403 /*
 404  * Discard a peer record.
 405  */
 406 static void __rxrpc_put_peer(struct rxrpc_peer *peer)
 407 {
 408         struct rxrpc_net *rxnet = peer->local->rxnet;
 409
 410         ASSERT(hlist_empty(&peer->error_targets));
 411
 412         spin_lock(&rxnet->peer_hash_lock);
 413         hash_del_rcu(&peer->hash_link);
 414         list_del_init(&peer->keepalive_link);
 415         spin_unlock(&rxnet->peer_hash_lock);
 416
 417         rxrpc_free_peer(peer);
 418 }
 419
 420 /*
 421  * Drop a ref on a peer record.
 422  */
 423 void rxrpc_put_peer(struct rxrpc_peer *peer, enum rxrpc_peer_trace why)
 424 {
 425         unsigned int debug_id;
 426         bool dead;
 427         int r;
 428
 429         if (peer) {
 430                 debug_id = peer->debug_id;
 431                 dead = __refcount_dec_and_test(&peer->ref, &r);
 432                 trace_rxrpc_peer(debug_id, r - 1, why);
 433                 if (dead)
 434                         __rxrpc_put_peer(peer);
 435         }
 436 }
 437
 438 /*
 439  * Make sure all peer records have been discarded.
 440  */
 441 void rxrpc_destroy_all_peers(struct rxrpc_net *rxnet)
 442 {
 443         struct rxrpc_peer *peer;
 444         int i;
 445
 446         for (i = 0; i < HASH_SIZE(rxnet->peer_hash); i++) {
 447                 if (hlist_empty(&rxnet->peer_hash[i]))
 448                         continue;
 449
 450                 hlist_for_each_entry(peer, &rxnet->peer_hash[i], hash_link) {
 451                         pr_err("Leaked peer %u {%u} %pISp\n",
 452                                peer->debug_id,
 453                                refcount_read(&peer->ref),
 454                                &peer->srx.transport);
 455                 }
 456         }
 457 }
 458
 459 /**
 460  * rxrpc_kernel_get_peer - Get the peer address of a call
 461  * @sock: The socket on which the call is in progress.
 462  * @call: The call to query
 463  * @_srx: Where to place the result
 464  *
 465  * Get the address of the remote peer in a call.
 466  */
 467 void rxrpc_kernel_get_peer(struct socket *sock, struct rxrpc_call *call,
 468                            struct sockaddr_rxrpc *_srx)
 469 {
 470         *_srx = call->peer->srx;
 471 }
 472 EXPORT_SYMBOL(rxrpc_kernel_get_peer);
 473
 474 /**
 475  * rxrpc_kernel_get_srtt - Get a call's peer smoothed RTT
 476  * @sock: The socket on which the call is in progress.
 477  * @call: The call to query
 478  * @_srtt: Where to store the SRTT value.
 479  *
 480  * Get the call's peer smoothed RTT in uS.
 481  */
 482 bool rxrpc_kernel_get_srtt(struct socket *sock, struct rxrpc_call *call,
 483                            u32 *_srtt)
 484 {
 485         struct rxrpc_peer *peer = call->peer;
 486
 487         if (peer->rtt_count == 0) {
 488                 *_srtt = 1000000; /* 1S */
 489                 return false;
 490         }
 491
 492         *_srtt = call->peer->srtt_us >> 3;
 493         return true;
 494 }
 495 EXPORT_SYMBOL(rxrpc_kernel_get_srtt);