405 lines
9.8 KiB
C
405 lines
9.8 KiB
C
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/* RxRPC remote transport endpoint record management
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*
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* Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/net.h>
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#include <linux/skbuff.h>
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#include <linux/udp.h>
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#include <linux/in.h>
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#include <linux/in6.h>
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#include <linux/slab.h>
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#include <linux/hashtable.h>
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#include <net/sock.h>
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#include <net/af_rxrpc.h>
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#include <net/ip.h>
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#include <net/route.h>
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#include <net/ip6_route.h>
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#include "ar-internal.h"
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static DEFINE_HASHTABLE(rxrpc_peer_hash, 10);
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static DEFINE_SPINLOCK(rxrpc_peer_hash_lock);
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/*
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* Hash a peer key.
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*/
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static unsigned long rxrpc_peer_hash_key(struct rxrpc_local *local,
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const struct sockaddr_rxrpc *srx)
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{
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const u16 *p;
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unsigned int i, size;
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unsigned long hash_key;
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_enter("");
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hash_key = (unsigned long)local / __alignof__(*local);
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hash_key += srx->transport_type;
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hash_key += srx->transport_len;
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hash_key += srx->transport.family;
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switch (srx->transport.family) {
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case AF_INET:
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hash_key += (u16 __force)srx->transport.sin.sin_port;
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size = sizeof(srx->transport.sin.sin_addr);
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p = (u16 *)&srx->transport.sin.sin_addr;
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break;
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#ifdef CONFIG_AF_RXRPC_IPV6
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case AF_INET6:
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hash_key += (u16 __force)srx->transport.sin.sin_port;
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size = sizeof(srx->transport.sin6.sin6_addr);
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p = (u16 *)&srx->transport.sin6.sin6_addr;
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break;
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#endif
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default:
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WARN(1, "AF_RXRPC: Unsupported transport address family\n");
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return 0;
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}
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/* Step through the peer address in 16-bit portions for speed */
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for (i = 0; i < size; i += sizeof(*p), p++)
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hash_key += *p;
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_leave(" 0x%lx", hash_key);
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return hash_key;
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}
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/*
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* Compare a peer to a key. Return -ve, 0 or +ve to indicate less than, same
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* or greater than.
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*
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* Unfortunately, the primitives in linux/hashtable.h don't allow for sorted
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* buckets and mid-bucket insertion, so we don't make full use of this
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* information at this point.
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*/
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static long rxrpc_peer_cmp_key(const struct rxrpc_peer *peer,
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struct rxrpc_local *local,
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const struct sockaddr_rxrpc *srx,
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unsigned long hash_key)
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{
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long diff;
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diff = ((peer->hash_key - hash_key) ?:
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((unsigned long)peer->local - (unsigned long)local) ?:
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(peer->srx.transport_type - srx->transport_type) ?:
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(peer->srx.transport_len - srx->transport_len) ?:
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(peer->srx.transport.family - srx->transport.family));
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if (diff != 0)
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return diff;
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switch (srx->transport.family) {
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case AF_INET:
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return ((u16 __force)peer->srx.transport.sin.sin_port -
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(u16 __force)srx->transport.sin.sin_port) ?:
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memcmp(&peer->srx.transport.sin.sin_addr,
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&srx->transport.sin.sin_addr,
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sizeof(struct in_addr));
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#ifdef CONFIG_AF_RXRPC_IPV6
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case AF_INET6:
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return ((u16 __force)peer->srx.transport.sin6.sin6_port -
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(u16 __force)srx->transport.sin6.sin6_port) ?:
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memcmp(&peer->srx.transport.sin6.sin6_addr,
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&srx->transport.sin6.sin6_addr,
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sizeof(struct in6_addr));
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#endif
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default:
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BUG();
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}
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}
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/*
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* Look up a remote transport endpoint for the specified address using RCU.
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*/
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static struct rxrpc_peer *__rxrpc_lookup_peer_rcu(
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struct rxrpc_local *local,
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const struct sockaddr_rxrpc *srx,
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unsigned long hash_key)
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{
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struct rxrpc_peer *peer;
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hash_for_each_possible_rcu(rxrpc_peer_hash, peer, hash_link, hash_key) {
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if (rxrpc_peer_cmp_key(peer, local, srx, hash_key) == 0) {
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if (atomic_read(&peer->usage) == 0)
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return NULL;
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return peer;
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}
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}
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return NULL;
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}
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/*
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* Look up a remote transport endpoint for the specified address using RCU.
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*/
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struct rxrpc_peer *rxrpc_lookup_peer_rcu(struct rxrpc_local *local,
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const struct sockaddr_rxrpc *srx)
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{
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struct rxrpc_peer *peer;
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unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
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peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
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if (peer) {
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_net("PEER %d {%pISp}", peer->debug_id, &peer->srx.transport);
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_leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
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}
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return peer;
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}
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/*
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* assess the MTU size for the network interface through which this peer is
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* reached
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*/
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static void rxrpc_assess_MTU_size(struct rxrpc_peer *peer)
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{
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struct dst_entry *dst;
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struct rtable *rt;
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struct flowi fl;
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struct flowi4 *fl4 = &fl.u.ip4;
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#ifdef CONFIG_AF_RXRPC_IPV6
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struct flowi6 *fl6 = &fl.u.ip6;
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#endif
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peer->if_mtu = 1500;
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memset(&fl, 0, sizeof(fl));
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switch (peer->srx.transport.family) {
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case AF_INET:
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rt = ip_route_output_ports(
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&init_net, fl4, NULL,
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peer->srx.transport.sin.sin_addr.s_addr, 0,
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htons(7000), htons(7001), IPPROTO_UDP, 0, 0);
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if (IS_ERR(rt)) {
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_leave(" [route err %ld]", PTR_ERR(rt));
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return;
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}
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dst = &rt->dst;
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break;
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#ifdef CONFIG_AF_RXRPC_IPV6
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case AF_INET6:
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fl6->flowi6_iif = LOOPBACK_IFINDEX;
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fl6->flowi6_scope = RT_SCOPE_UNIVERSE;
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fl6->flowi6_proto = IPPROTO_UDP;
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memcpy(&fl6->daddr, &peer->srx.transport.sin6.sin6_addr,
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sizeof(struct in6_addr));
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fl6->fl6_dport = htons(7001);
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fl6->fl6_sport = htons(7000);
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dst = ip6_route_output(&init_net, NULL, fl6);
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if (dst->error) {
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_leave(" [route err %d]", dst->error);
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return;
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}
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break;
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#endif
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default:
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BUG();
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}
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peer->if_mtu = dst_mtu(dst);
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dst_release(dst);
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_leave(" [if_mtu %u]", peer->if_mtu);
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}
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/*
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* Allocate a peer.
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*/
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struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *local, gfp_t gfp)
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{
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struct rxrpc_peer *peer;
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_enter("");
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peer = kzalloc(sizeof(struct rxrpc_peer), gfp);
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if (peer) {
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atomic_set(&peer->usage, 1);
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peer->local = local;
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INIT_HLIST_HEAD(&peer->error_targets);
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INIT_WORK(&peer->error_distributor,
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&rxrpc_peer_error_distributor);
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peer->service_conns = RB_ROOT;
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seqlock_init(&peer->service_conn_lock);
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spin_lock_init(&peer->lock);
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peer->debug_id = atomic_inc_return(&rxrpc_debug_id);
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}
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_leave(" = %p", peer);
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return peer;
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}
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/*
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* Initialise peer record.
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*/
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static void rxrpc_init_peer(struct rxrpc_peer *peer, unsigned long hash_key)
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{
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peer->hash_key = hash_key;
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rxrpc_assess_MTU_size(peer);
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peer->mtu = peer->if_mtu;
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peer->rtt_last_req = ktime_get_real();
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switch (peer->srx.transport.family) {
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case AF_INET:
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peer->hdrsize = sizeof(struct iphdr);
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break;
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#ifdef CONFIG_AF_RXRPC_IPV6
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case AF_INET6:
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peer->hdrsize = sizeof(struct ipv6hdr);
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break;
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#endif
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default:
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BUG();
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}
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switch (peer->srx.transport_type) {
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case SOCK_DGRAM:
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peer->hdrsize += sizeof(struct udphdr);
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break;
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default:
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BUG();
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}
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peer->hdrsize += sizeof(struct rxrpc_wire_header);
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peer->maxdata = peer->mtu - peer->hdrsize;
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}
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/*
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* Set up a new peer.
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*/
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static struct rxrpc_peer *rxrpc_create_peer(struct rxrpc_local *local,
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struct sockaddr_rxrpc *srx,
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unsigned long hash_key,
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gfp_t gfp)
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{
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struct rxrpc_peer *peer;
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_enter("");
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peer = rxrpc_alloc_peer(local, gfp);
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if (peer) {
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memcpy(&peer->srx, srx, sizeof(*srx));
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rxrpc_init_peer(peer, hash_key);
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}
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_leave(" = %p", peer);
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return peer;
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}
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/*
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* Set up a new incoming peer. The address is prestored in the preallocated
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* peer.
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*/
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struct rxrpc_peer *rxrpc_lookup_incoming_peer(struct rxrpc_local *local,
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struct rxrpc_peer *prealloc)
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{
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struct rxrpc_peer *peer;
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unsigned long hash_key;
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hash_key = rxrpc_peer_hash_key(local, &prealloc->srx);
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prealloc->local = local;
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rxrpc_init_peer(prealloc, hash_key);
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spin_lock(&rxrpc_peer_hash_lock);
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/* Need to check that we aren't racing with someone else */
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peer = __rxrpc_lookup_peer_rcu(local, &prealloc->srx, hash_key);
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if (peer && !rxrpc_get_peer_maybe(peer))
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peer = NULL;
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if (!peer) {
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peer = prealloc;
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hash_add_rcu(rxrpc_peer_hash, &peer->hash_link, hash_key);
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}
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spin_unlock(&rxrpc_peer_hash_lock);
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return peer;
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}
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/*
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* obtain a remote transport endpoint for the specified address
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*/
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struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_local *local,
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struct sockaddr_rxrpc *srx, gfp_t gfp)
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{
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struct rxrpc_peer *peer, *candidate;
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unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
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_enter("{%pISp}", &srx->transport);
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/* search the peer list first */
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rcu_read_lock();
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peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
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if (peer && !rxrpc_get_peer_maybe(peer))
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peer = NULL;
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rcu_read_unlock();
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if (!peer) {
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/* The peer is not yet present in hash - create a candidate
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* for a new record and then redo the search.
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*/
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candidate = rxrpc_create_peer(local, srx, hash_key, gfp);
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if (!candidate) {
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_leave(" = NULL [nomem]");
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return NULL;
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}
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spin_lock_bh(&rxrpc_peer_hash_lock);
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/* Need to check that we aren't racing with someone else */
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peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
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if (peer && !rxrpc_get_peer_maybe(peer))
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peer = NULL;
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if (!peer)
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hash_add_rcu(rxrpc_peer_hash,
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&candidate->hash_link, hash_key);
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spin_unlock_bh(&rxrpc_peer_hash_lock);
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if (peer)
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kfree(candidate);
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else
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peer = candidate;
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}
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_net("PEER %d {%pISp}", peer->debug_id, &peer->srx.transport);
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_leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
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return peer;
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}
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|
|
||
|
|
/*
|
||
|
|
* Discard a ref on a remote peer record.
|
||
|
|
*/
|
||
|
|
void __rxrpc_put_peer(struct rxrpc_peer *peer)
|
||
|
|
{
|
||
|
|
ASSERT(hlist_empty(&peer->error_targets));
|
||
|
|
|
||
|
|
spin_lock_bh(&rxrpc_peer_hash_lock);
|
||
|
|
hash_del_rcu(&peer->hash_link);
|
||
|
|
spin_unlock_bh(&rxrpc_peer_hash_lock);
|
||
|
|
|
||
|
|
kfree_rcu(peer, rcu);
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* rxrpc_kernel_get_peer - Get the peer address of a call
|
||
|
|
* @sock: The socket on which the call is in progress.
|
||
|
|
* @call: The call to query
|
||
|
|
* @_srx: Where to place the result
|
||
|
|
*
|
||
|
|
* Get the address of the remote peer in a call.
|
||
|
|
*/
|
||
|
|
void rxrpc_kernel_get_peer(struct socket *sock, struct rxrpc_call *call,
|
||
|
|
struct sockaddr_rxrpc *_srx)
|
||
|
|
{
|
||
|
|
*_srx = call->peer->srx;
|
||
|
|
}
|
||
|
|
EXPORT_SYMBOL(rxrpc_kernel_get_peer);
|