net/rxrpc/peer_object.c

   1 /* RxRPC remote transport endpoint record management
   2  *
   3  * Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13
  14 #include <linux/module.h>
  15 #include <linux/net.h>
  16 #include <linux/skbuff.h>
  17 #include <linux/udp.h>
  18 #include <linux/in.h>
  19 #include <linux/in6.h>
  20 #include <linux/slab.h>
  21 #include <linux/hashtable.h>
  22 #include <net/sock.h>
  23 #include <net/af_rxrpc.h>
  24 #include <net/ip.h>
  25 #include <net/route.h>
  26 #include <net/ip6_route.h>
  27 #include "ar-internal.h"
  28
  29 static DEFINE_HASHTABLE(rxrpc_peer_hash, 10);
  30 static DEFINE_SPINLOCK(rxrpc_peer_hash_lock);
  31
  32 /*
  33  * Hash a peer key.
  34  */
  35 static unsigned long rxrpc_peer_hash_key(struct rxrpc_local *local,
  36                                          const struct sockaddr_rxrpc *srx)
  37 {
  38         const u16 *p;
  39         unsigned int i, size;
  40         unsigned long hash_key;
  41
  42         _enter("");
  43
  44         hash_key = (unsigned long)local / __alignof__(*local);
  45         hash_key += srx->transport_type;
  46         hash_key += srx->transport_len;
  47         hash_key += srx->transport.family;
  48
  49         switch (srx->transport.family) {
  50         case AF_INET:
  51                 hash_key += (u16 __force)srx->transport.sin.sin_port;
  52                 size = sizeof(srx->transport.sin.sin_addr);
  53                 p = (u16 *)&srx->transport.sin.sin_addr;
  54                 break;
  55 #ifdef CONFIG_AF_RXRPC_IPV6
  56         case AF_INET6:
  57                 hash_key += (u16 __force)srx->transport.sin.sin_port;
  58                 size = sizeof(srx->transport.sin6.sin6_addr);
  59                 p = (u16 *)&srx->transport.sin6.sin6_addr;
  60                 break;
  61 #endif
  62         default:
  63                 WARN(1, "AF_RXRPC: Unsupported transport address family\n");
  64                 return 0;
  65         }
  66
  67         /* Step through the peer address in 16-bit portions for speed */
  68         for (i = 0; i < size; i += sizeof(*p), p++)
  69                 hash_key += *p;
  70
  71         _leave(" 0x%lx", hash_key);
  72         return hash_key;
  73 }
  74
  75 /*
  76  * Compare a peer to a key.  Return -ve, 0 or +ve to indicate less than, same
  77  * or greater than.
  78  *
  79  * Unfortunately, the primitives in linux/hashtable.h don't allow for sorted
  80  * buckets and mid-bucket insertion, so we don't make full use of this
  81  * information at this point.
  82  */
  83 static long rxrpc_peer_cmp_key(const struct rxrpc_peer *peer,
  84                                struct rxrpc_local *local,
  85                                const struct sockaddr_rxrpc *srx,
  86                                unsigned long hash_key)
  87 {
  88         long diff;
  89
  90         diff = ((peer->hash_key - hash_key) ?:
  91                 ((unsigned long)peer->local - (unsigned long)local) ?:
  92                 (peer->srx.transport_type - srx->transport_type) ?:
  93                 (peer->srx.transport_len - srx->transport_len) ?:
  94                 (peer->srx.transport.family - srx->transport.family));
  95         if (diff != 0)
  96                 return diff;
  97
  98         switch (srx->transport.family) {
  99         case AF_INET:
 100                 return ((u16 __force)peer->srx.transport.sin.sin_port -
 101                         (u16 __force)srx->transport.sin.sin_port) ?:
 102                         memcmp(&peer->srx.transport.sin.sin_addr,
 103                                &srx->transport.sin.sin_addr,
 104                                sizeof(struct in_addr));
 105 #ifdef CONFIG_AF_RXRPC_IPV6
 106         case AF_INET6:
 107                 return ((u16 __force)peer->srx.transport.sin6.sin6_port -
 108                         (u16 __force)srx->transport.sin6.sin6_port) ?:
 109                         memcmp(&peer->srx.transport.sin6.sin6_addr,
 110                                &srx->transport.sin6.sin6_addr,
 111                                sizeof(struct in6_addr));
 112 #endif
 113         default:
 114                 BUG();
 115         }
 116 }
 117
 118 /*
 119  * Look up a remote transport endpoint for the specified address using RCU.
 120  */
 121 static struct rxrpc_peer *__rxrpc_lookup_peer_rcu(
 122         struct rxrpc_local *local,
 123         const struct sockaddr_rxrpc *srx,
 124         unsigned long hash_key)
 125 {
 126         struct rxrpc_peer *peer;
 127
 128         hash_for_each_possible_rcu(rxrpc_peer_hash, peer, hash_link, hash_key) {
 129                 if (rxrpc_peer_cmp_key(peer, local, srx, hash_key) == 0) {
 130                         if (atomic_read(&peer->usage) == 0)
 131                                 return NULL;
 132                         return peer;
 133                 }
 134         }
 135
 136         return NULL;
 137 }
 138
 139 /*
 140  * Look up a remote transport endpoint for the specified address using RCU.
 141  */
 142 struct rxrpc_peer *rxrpc_lookup_peer_rcu(struct rxrpc_local *local,
 143                                          const struct sockaddr_rxrpc *srx)
 144 {
 145         struct rxrpc_peer *peer;
 146         unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
 147
 148         peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
 149         if (peer) {
 150                 _net("PEER %d {%pISp}", peer->debug_id, &peer->srx.transport);
 151                 _leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
 152         }
 153         return peer;
 154 }
 155
 156 /*
 157  * assess the MTU size for the network interface through which this peer is
 158  * reached
 159  */
 160 static void rxrpc_assess_MTU_size(struct rxrpc_peer *peer)
 161 {
 162         struct dst_entry *dst;
 163         struct rtable *rt;
 164         struct flowi fl;
 165         struct flowi4 *fl4 = &fl.u.ip4;
 166 #ifdef CONFIG_AF_RXRPC_IPV6
 167         struct flowi6 *fl6 = &fl.u.ip6;
 168 #endif
 169
 170         peer->if_mtu = 1500;
 171
 172         memset(&fl, 0, sizeof(fl));
 173         switch (peer->srx.transport.family) {
 174         case AF_INET:
 175                 rt = ip_route_output_ports(
 176                         &init_net, fl4, NULL,
 177                         peer->srx.transport.sin.sin_addr.s_addr, 0,
 178                         htons(7000), htons(7001), IPPROTO_UDP, 0, 0);
 179                 if (IS_ERR(rt)) {
 180                         _leave(" [route err %ld]", PTR_ERR(rt));
 181                         return;
 182                 }
 183                 dst = &rt->dst;
 184                 break;
 185
 186 #ifdef CONFIG_AF_RXRPC_IPV6
 187         case AF_INET6:
 188                 fl6->flowi6_iif = LOOPBACK_IFINDEX;
 189                 fl6->flowi6_scope = RT_SCOPE_UNIVERSE;
 190                 fl6->flowi6_proto = IPPROTO_UDP;
 191                 memcpy(&fl6->daddr, &peer->srx.transport.sin6.sin6_addr,
 192                        sizeof(struct in6_addr));
 193                 fl6->fl6_dport = htons(7001);
 194                 fl6->fl6_sport = htons(7000);
 195                 dst = ip6_route_output(&init_net, NULL, fl6);
 196                 if (dst->error) {
 197                         _leave(" [route err %d]", dst->error);
 198                         return;
 199                 }
 200                 break;
 201 #endif
 202
 203         default:
 204                 BUG();
 205         }
 206
 207         peer->if_mtu = dst_mtu(dst);
 208         dst_release(dst);
 209
 210         _leave(" [if_mtu %u]", peer->if_mtu);
 211 }
 212
 213 /*
 214  * Allocate a peer.
 215  */
 216 struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *local, gfp_t gfp)
 217 {
 218         struct rxrpc_peer *peer;
 219
 220         _enter("");
 221
 222         peer = kzalloc(sizeof(struct rxrpc_peer), gfp);
 223         if (peer) {
 224                 atomic_set(&peer->usage, 1);
 225                 peer->local = local;
 226                 INIT_HLIST_HEAD(&peer->error_targets);
 227                 INIT_WORK(&peer->error_distributor,
 228                           &rxrpc_peer_error_distributor);
 229                 peer->service_conns = RB_ROOT;
 230                 seqlock_init(&peer->service_conn_lock);
 231                 spin_lock_init(&peer->lock);
 232                 peer->debug_id = atomic_inc_return(&rxrpc_debug_id);
 233         }
 234
 235         _leave(" = %p", peer);
 236         return peer;
 237 }
 238
 239 /*
 240  * Initialise peer record.
 241  */
 242 static void rxrpc_init_peer(struct rxrpc_peer *peer, unsigned long hash_key)
 243 {
 244         peer->hash_key = hash_key;
 245         rxrpc_assess_MTU_size(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);
 287         if (peer) {
 288                 memcpy(&peer->srx, srx, sizeof(*srx));
 289                 rxrpc_init_peer(peer, hash_key);
 290         }
 291
 292         _leave(" = %p", peer);
 293         return peer;
 294 }
 295
 296 /*
 297  * Set up a new incoming peer.  The address is prestored in the preallocated
 298  * peer.
 299  */
 300 struct rxrpc_peer *rxrpc_lookup_incoming_peer(struct rxrpc_local *local,
 301                                               struct rxrpc_peer *prealloc)
 302 {
 303         struct rxrpc_peer *peer;
 304         unsigned long hash_key;
 305
 306         hash_key = rxrpc_peer_hash_key(local, &prealloc->srx);
 307         prealloc->local = local;
 308         rxrpc_init_peer(prealloc, hash_key);
 309
 310         spin_lock(&rxrpc_peer_hash_lock);
 311
 312         /* Need to check that we aren't racing with someone else */
 313         peer = __rxrpc_lookup_peer_rcu(local, &prealloc->srx, hash_key);
 314         if (peer && !rxrpc_get_peer_maybe(peer))
 315                 peer = NULL;
 316         if (!peer) {
 317                 peer = prealloc;
 318                 hash_add_rcu(rxrpc_peer_hash, &peer->hash_link, hash_key);
 319         }
 320
 321         spin_unlock(&rxrpc_peer_hash_lock);
 322         return peer;
 323 }
 324
 325 /*
 326  * obtain a remote transport endpoint for the specified address
 327  */
 328 struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_local *local,
 329                                      struct sockaddr_rxrpc *srx, gfp_t gfp)
 330 {
 331         struct rxrpc_peer *peer, *candidate;
 332         unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
 333
 334         _enter("{%pISp}", &srx->transport);
 335
 336         /* search the peer list first */
 337         rcu_read_lock();
 338         peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
 339         if (peer && !rxrpc_get_peer_maybe(peer))
 340                 peer = NULL;
 341         rcu_read_unlock();
 342
 343         if (!peer) {
 344                 /* The peer is not yet present in hash - create a candidate
 345                  * for a new record and then redo the search.
 346                  */
 347                 candidate = rxrpc_create_peer(local, srx, hash_key, gfp);
 348                 if (!candidate) {
 349                         _leave(" = NULL [nomem]");
 350                         return NULL;
 351                 }
 352
 353                 spin_lock_bh(&rxrpc_peer_hash_lock);
 354
 355                 /* Need to check that we aren't racing with someone else */
 356                 peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
 357                 if (peer && !rxrpc_get_peer_maybe(peer))
 358                         peer = NULL;
 359                 if (!peer)
 360                         hash_add_rcu(rxrpc_peer_hash,
 361                                      &candidate->hash_link, hash_key);
 362
 363                 spin_unlock_bh(&rxrpc_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  * Discard a ref on a remote peer record.
 379  */
 380 void __rxrpc_put_peer(struct rxrpc_peer *peer)
 381 {
 382         ASSERT(hlist_empty(&peer->error_targets));
 383
 384         spin_lock_bh(&rxrpc_peer_hash_lock);
 385         hash_del_rcu(&peer->hash_link);
 386         spin_unlock_bh(&rxrpc_peer_hash_lock);
 387
 388         kfree_rcu(peer, rcu);
 389 }
 390
 391 /**
 392  * rxrpc_kernel_get_peer - Get the peer address of a call
 393  * @sock: The socket on which the call is in progress.
 394  * @call: The call to query
 395  * @_srx: Where to place the result
 396  *
 397  * Get the address of the remote peer in a call.
 398  */
 399 void rxrpc_kernel_get_peer(struct socket *sock, struct rxrpc_call *call,
 400                            struct sockaddr_rxrpc *_srx)
 401 {
 402         *_srx = call->peer->srx;
 403 }
 404 EXPORT_SYMBOL(rxrpc_kernel_get_peer);