/* RxRPC remote transport endpoint record management
*
* Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
* Written by David Howells (dhowells@redhat.com)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>
#include <linux/net.h>
#include <linux/skbuff.h>
#include <linux/udp.h>
#include <linux/in.h>
#include <linux/in6.h>
#include <linux/slab.h>
#include <linux/hashtable.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include <net/ip.h>
#include <net/route.h>
#include <net/ip6_route.h>
#include "ar-internal.h"
/*
* Hash a peer key.
*/
static unsigned long rxrpc_peer_hash_key(struct rxrpc_local *local,
const struct sockaddr_rxrpc *srx)
{
const u16 *p;
unsigned int i, size;
unsigned long hash_key;
_enter("");
hash_key = (unsigned long)local / __alignof__(*local);
hash_key += srx->transport_type;
hash_key += srx->transport_len;
hash_key += srx->transport.family;
switch (srx->transport.family) {
case AF_INET:
hash_key += (u16 __force)srx->transport.sin.sin_port;
size = sizeof(srx->transport.sin.sin_addr);
p = (u16 *)&srx->transport.sin.sin_addr;
break;
#ifdef CONFIG_AF_RXRPC_IPV6
case AF_INET6:
hash_key += (u16 __force)srx->transport.sin.sin_port;
size = sizeof(srx->transport.sin6.sin6_addr);
p = (u16 *)&srx->transport.sin6.sin6_addr;
break;
#endif
default:
WARN(1, "AF_RXRPC: Unsupported transport address family\n");
return 0;
}
/* Step through the peer address in 16-bit portions for speed */
for (i = 0; i < size; i += sizeof(*p), p++)
hash_key += *p;
_leave(" 0x%lx", hash_key);
return hash_key;
}
/*
* Compare a peer to a key. Return -ve, 0 or +ve to indicate less than, same
* or greater than.
*
* Unfortunately, the primitives in linux/hashtable.h don't allow for sorted
* buckets and mid-bucket insertion, so we don't make full use of this
* information at this point.
*/
static long rxrpc_peer_cmp_key(const struct rxrpc_peer *peer,
struct rxrpc_local *local,
const struct sockaddr_rxrpc *srx,
unsigned long hash_key)
{
long diff;
diff = ((peer->hash_key - hash_key) ?:
((unsigned long)peer->local - (unsigned long)local) ?:
(peer->srx.transport_type - srx->transport_type) ?:
(peer->srx.transport_len - srx->transport_len) ?:
(peer->srx.transport.family - srx->transport.family));
if (diff != 0)
return diff;
switch (srx->transport.family) {
case AF_INET:
return ((u16 __force)peer->srx.transport.sin.sin_port -
(u16 __force)srx->transport.sin.sin_port) ?:
memcmp(&peer->srx.transport.sin.sin_addr,
&srx->transport.sin.sin_addr,
sizeof(struct in_addr));
#ifdef CONFIG_AF_RXRPC_IPV6
case AF_INET6:
return ((u16 __force)peer->srx.transport.sin6.sin6_port -
(u16 __force)srx->transport.sin6.sin6_port) ?:
memcmp(&peer->srx.transport.sin6.sin6_addr,
&srx->transport.sin6.sin6_addr,
sizeof(struct in6_addr));
#endif
default:
BUG();
}
}
/*
* Look up a remote transport endpoint for the specified address using RCU.
*/
static struct rxrpc_peer *__rxrpc_lookup_peer_rcu(
struct rxrpc_local *local,
const struct sockaddr_rxrpc *srx,
unsigned long hash_key)
{
struct rxrpc_peer *peer;
struct rxrpc_net *rxnet = local->rxnet;
hash_for_each_possible_rcu(rxnet->peer_hash, peer, hash_link, hash_key) {
if (rxrpc_peer_cmp_key(peer, local, srx, hash_key) == 0) {
if (atomic_read(&peer->usage) == 0)
return NULL;
return peer;
}
}
return NULL;
}
/*
* Look up a remote transport endpoint for the specified address using RCU.
*/
struct rxrpc_peer *rxrpc_lookup_peer_rcu(struct rxrpc_local *local,
const struct sockaddr_rxrpc *srx)
{
struct rxrpc_peer *peer;
unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
if (peer) {
_net("PEER %d {%pISp}", peer->debug_id, &peer->srx.transport);
_leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
}
return peer;
}
/*
* assess the MTU size for the network interface through which this peer is
* reached
*/
static void rxrpc_assess_MTU_size(struct rxrpc_peer *peer)
{
struct dst_entry *dst;
struct rtable *rt;
struct flowi fl;
struct flowi4 *fl4 = &fl.u.ip4;
#ifdef CONFIG_AF_RXRPC_IPV6
struct flowi6 *fl6 = &fl.u.ip6;
#endif
peer->if_mtu = 1500;
memset(&fl, 0, sizeof(fl));
switch (peer->srx.transport.family) {
case AF_INET:
rt = ip_route_output_ports(
&init_net, fl4, NULL,
peer->srx.transport.sin.sin_addr.s_addr, 0,
htons(7000), htons(7001), IPPROTO_UDP, 0, 0);
if (IS_ERR(rt)) {
_leave(" [route err %ld]", PTR_ERR(rt));
return;
}
dst = &rt->dst;
break;
#ifdef CONFIG_AF_RXRPC_IPV6
case AF_INET6:
fl6->flowi6_iif = LOOPBACK_IFINDEX;
fl6->flowi6_scope = RT_SCOPE_UNIVERSE;
fl6->flowi6_proto = IPPROTO_UDP;
memcpy(&fl6->daddr, &peer->srx.transport.sin6.sin6_addr,
sizeof(struct in6_addr));
fl6->fl6_dport = htons(7001);
fl6->fl6_sport = htons(7000);
dst = ip6_route_output(&init_net, NULL, fl6);
if (dst->error) {
_leave(" [route err %d]", dst->error);
return;
}
break;
#endif
default:
BUG();
}
peer->if_mtu = dst_mtu(dst);
dst_release(dst);
_leave(" [if_mtu %u]", peer->if_mtu);
}
/*
* Allocate a peer.
*/
struct rxrpc_peer *rxrpc_alloc_peer(struct rxrpc_local *local, gfp_t gfp)
{
struct rxrpc_peer *peer;
_enter("");
peer = kzalloc(sizeof(struct rxrpc_peer), gfp);
if (peer) {
atomic_set(&peer->usage, 1);
peer->local = local;
INIT_HLIST_HEAD(&peer->error_targets);
INIT_WORK(&peer->error_distributor,
&rxrpc_peer_error_distributor);
peer->service_conns = RB_ROOT;
seqlock_init(&peer->service_conn_lock);
spin_lock_init(&peer->lock);
peer->debug_id = atomic_inc_return(&rxrpc_debug_id);
if (RXRPC_TX_SMSS > 2190)
peer->cong_cwnd = 2;
else if (RXRPC_TX_SMSS > 1095)
peer->cong_cwnd = 3;
else
peer->cong_cwnd = 4;
}
_leave(" = %p", peer);
return peer;
}
/*
* Initialise peer record.
*/
static void rxrpc_init_peer(struct rxrpc_peer *peer, unsigned long hash_key)
{
peer->hash_key = hash_key;
rxrpc_assess_MTU_size(peer);
peer->mtu = peer->if_mtu;
peer->rtt_last_req = ktime_get_real();
switch (peer->srx.transport.family) {
case AF_INET:
peer->hdrsize = sizeof(struct iphdr);
break;
#ifdef CONFIG_AF_RXRPC_IPV6
case AF_INET6:
peer->hdrsize = sizeof(struct ipv6hdr);
break;
#endif
default:
BUG();
}
switch (peer->srx.transport_type) {
case SOCK_DGRAM:
peer->hdrsize += sizeof(struct udphdr);
break;
default:
BUG();
}
peer->hdrsize += sizeof(struct rxrpc_wire_header);
peer->maxdata = peer->mtu - peer->hdrsize;
}
/*
* Set up a new peer.
*/
static struct rxrpc_peer *rxrpc_create_peer(struct rxrpc_local *local,
struct sockaddr_rxrpc *srx,
unsigned long hash_key,
gfp_t gfp)
{
struct rxrpc_peer *peer;
_enter("");
peer = rxrpc_alloc_peer(local, gfp);
if (peer) {
memcpy(&peer->srx, srx, sizeof(*srx));
rxrpc_init_peer(peer, hash_key);
}
_leave(" = %p", peer);
return peer;
}
/*
* Set up a new incoming peer. The address is prestored in the preallocated
* peer.
*/
struct rxrpc_peer *rxrpc_lookup_incoming_peer(struct rxrpc_local *local,
struct rxrpc_peer *prealloc)
{
struct rxrpc_peer *peer;
struct rxrpc_net *rxnet = local->rxnet;
unsigned long hash_key;
hash_key = rxrpc_peer_hash_key(local, &prealloc->srx);
prealloc->local = local;
rxrpc_init_peer(prealloc, hash_key);
spin_lock(&rxnet->peer_hash_lock);
/* Need to check that we aren't racing with someone else */
peer = __rxrpc_lookup_peer_rcu(local, &prealloc->srx, hash_key);
if (peer && !rxrpc_get_peer_maybe(peer))
peer = NULL;
if (!peer) {
peer = prealloc;
hash_add_rcu(rxnet->peer_hash, &peer->hash_link, hash_key);
}
spin_unlock(&rxnet->peer_hash_lock);
return peer;
}
/*
* obtain a remote transport endpoint for the specified address
*/
struct rxrpc_peer *rxrpc_lookup_peer(struct rxrpc_local *local,
struct sockaddr_rxrpc *srx, gfp_t gfp)
{
struct rxrpc_peer *peer, *candidate;
struct rxrpc_net *rxnet = local->rxnet;
unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
_enter("{%pISp}", &srx->transport);
/* search the peer list first */
rcu_read_lock();
peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
if (peer && !rxrpc_get_peer_maybe(peer))
peer = NULL;
rcu_read_unlock();
if (!peer) {
/* The peer is not yet present in hash - create a candidate
* for a new record and then redo the search.
*/
candidate = rxrpc_create_peer(local, srx, hash_key, gfp);
if (!candidate) {
_leave(" = NULL [nomem]");
return NULL;
}
spin_lock_bh(&rxnet->peer_hash_lock);
/* Need to check that we aren't racing with someone else */
peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
if (peer && !rxrpc_get_peer_maybe(peer))
peer = NULL;
if (!peer)
hash_add_rcu(rxnet->peer_hash,
&candidate->hash_link, hash_key);
spin_unlock_bh(&rxnet->peer_hash_lock);
if (peer)
kfree(candidate);
else
peer = candidate;
}
_net("PEER %d {%pISp}", peer->debug_id, &peer->srx.transport);
_leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
return peer;
}
/*
* Discard a ref on a remote peer record.
*/
void __rxrpc_put_peer(struct rxrpc_peer *peer)
{
struct rxrpc_net *rxnet = peer->local->rxnet;
ASSERT(hlist_empty(&peer->error_targets));
spin_lock_bh(&rxnet->peer_hash_lock);
hash_del_rcu(&peer->hash_link);
spin_unlock_bh(&rxnet->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);
/**
* rxrpc_kernel_get_rtt - Get a call's peer RTT
* @sock: The socket on which the call is in progress.
* @call: The call to query
*
* Get the call's peer RTT.
*/
u64 rxrpc_kernel_get_rtt(struct socket *sock, struct rxrpc_call *call)
{
return call->peer->rtt;
}
EXPORT_SYMBOL(rxrpc_kernel_get_rtt);
