// SPDX-License-Identifier: GPL-2.0-or-later
/* RxRPC remote transport endpoint record management
*
* Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
* Written by David Howells ([email protected])
*/
#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"
static const struct sockaddr_rxrpc rxrpc_null_addr;
/*
* 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 &&
refcount_read(&peer->ref) > 0)
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)
_leave(" = %p {u=%d}", peer, refcount_read(&peer->ref));
return peer;
}
/*
* assess the MTU size for the network interface through which this peer is
* reached
*/
static void rxrpc_assess_MTU_size(struct rxrpc_local *local,
struct rxrpc_peer *peer)
{
struct net *net = local->net;
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(
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(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,
enum rxrpc_peer_trace why)
{
struct rxrpc_peer *peer;
_enter("");
peer = kzalloc(sizeof(struct rxrpc_peer), gfp);
if (peer) {
refcount_set(&peer->ref, 1);
peer->local = rxrpc_get_local(local, rxrpc_local_get_peer);
INIT_HLIST_HEAD(&peer->error_targets);
peer->service_conns = RB_ROOT;
seqlock_init(&peer->service_conn_lock);
spin_lock_init(&peer->lock);
spin_lock_init(&peer->rtt_input_lock);
peer->debug_id = atomic_inc_return(&rxrpc_debug_id);
rxrpc_peer_init_rtt(peer);
peer->cong_ssthresh = RXRPC_TX_MAX_WINDOW;
trace_rxrpc_peer(peer->debug_id, 1, why);
}
_leave(" = %p", peer);
return peer;
}
/*
* Initialise peer record.
*/
static void rxrpc_init_peer(struct rxrpc_local *local, struct rxrpc_peer *peer,
unsigned long hash_key)
{
peer->hash_key = hash_key;
rxrpc_assess_MTU_size(local, 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, rxrpc_peer_new_client);
if (peer) {
memcpy(&peer->srx, srx, sizeof(*srx));
rxrpc_init_peer(local, peer, hash_key);
}
_leave(" = %p", peer);
return peer;
}
static void rxrpc_free_peer(struct rxrpc_peer *peer)
{
trace_rxrpc_peer(peer->debug_id, 0, rxrpc_peer_free);
rxrpc_put_local(peer->local, rxrpc_local_put_peer);
kfree_rcu(peer, rcu);
}
/*
* Set up a new incoming peer. There shouldn't be any other matching peers
* since we've already done a search in the list from the non-reentrant context
* (the data_ready handler) that is the only place we can add new peers.
*/
void rxrpc_new_incoming_peer(struct rxrpc_local *local, struct rxrpc_peer *peer)
{
struct rxrpc_net *rxnet = local->rxnet;
unsigned long hash_key;
hash_key = rxrpc_peer_hash_key(local, &peer->srx);
rxrpc_init_peer(local, peer, hash_key);
spin_lock(&rxnet->peer_hash_lock);
hash_add_rcu(rxnet->peer_hash, &peer->hash_link, hash_key);
list_add_tail(&peer->keepalive_link, &rxnet->peer_keepalive_new);
spin_unlock(&rxnet->peer_hash_lock);
}
/*
* 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, rxrpc_peer_get_lookup_client))
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(&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, rxrpc_peer_get_lookup_client))
peer = NULL;
if (!peer) {
hash_add_rcu(rxnet->peer_hash,
&candidate->hash_link, hash_key);
list_add_tail(&candidate->keepalive_link,
&rxnet->peer_keepalive_new);
}
spin_unlock(&rxnet->peer_hash_lock);
if (peer)
rxrpc_free_peer(candidate);
else
peer = candidate;
}
_leave(" = %p {u=%d}", peer, refcount_read(&peer->ref));
return peer;
}
/*
* Get a ref on a peer record.
*/
struct rxrpc_peer *rxrpc_get_peer(struct rxrpc_peer *peer, enum rxrpc_peer_trace why)
{
int r;
__refcount_inc(&peer->ref, &r);
trace_rxrpc_peer(peer->debug_id, r + 1, why);
return peer;
}
/*
* Get a ref on a peer record unless its usage has already reached 0.
*/
struct rxrpc_peer *rxrpc_get_peer_maybe(struct rxrpc_peer *peer,
enum rxrpc_peer_trace why)
{
int r;
if (peer) {
if (__refcount_inc_not_zero(&peer->ref, &r))
trace_rxrpc_peer(peer->debug_id, r + 1, why);
else
peer = NULL;
}
return peer;
}
/*
* Discard a peer record.
*/
static void __rxrpc_put_peer(struct rxrpc_peer *peer)
{
struct rxrpc_net *rxnet = peer->local->rxnet;
ASSERT(hlist_empty(&peer->error_targets));
spin_lock(&rxnet->peer_hash_lock);
hash_del_rcu(&peer->hash_link);
list_del_init(&peer->keepalive_link);
spin_unlock(&rxnet->peer_hash_lock);
rxrpc_free_peer(peer);
}
/*
* Drop a ref on a peer record.
*/
void rxrpc_put_peer(struct rxrpc_peer *peer, enum rxrpc_peer_trace why)
{
unsigned int debug_id;
bool dead;
int r;
if (peer) {
debug_id = peer->debug_id;
dead = __refcount_dec_and_test(&peer->ref, &r);
trace_rxrpc_peer(debug_id, r - 1, why);
if (dead)
__rxrpc_put_peer(peer);
}
}
/*
* Make sure all peer records have been discarded.
*/
void rxrpc_destroy_all_peers(struct rxrpc_net *rxnet)
{
struct rxrpc_peer *peer;
int i;
for (i = 0; i < HASH_SIZE(rxnet->peer_hash); i++) {
if (hlist_empty(&rxnet->peer_hash[i]))
continue;
hlist_for_each_entry(peer, &rxnet->peer_hash[i], hash_link) {
pr_err("Leaked peer %u {%u} %pISp\n",
peer->debug_id,
refcount_read(&peer->ref),
&peer->srx.transport);
}
}
}
/**
* rxrpc_kernel_get_call_peer - Get the peer address of a call
* @sock: The socket on which the call is in progress.
* @call: The call to query
*
* Get a record for the remote peer in a call.
*/
struct rxrpc_peer *rxrpc_kernel_get_call_peer(struct socket *sock, struct rxrpc_call *call)
{
return call->peer;
}
EXPORT_SYMBOL(rxrpc_kernel_get_call_peer);
/**
* rxrpc_kernel_get_srtt - Get a call's peer smoothed RTT
* @peer: The peer to query
*
* Get the call's peer smoothed RTT in uS or UINT_MAX if we have no samples.
*/
unsigned int rxrpc_kernel_get_srtt(const struct rxrpc_peer *peer)
{
return peer->rtt_count > 0 ? peer->srtt_us >> 3 : UINT_MAX;
}
EXPORT_SYMBOL(rxrpc_kernel_get_srtt);
/**
* rxrpc_kernel_remote_srx - Get the address of a peer
* @peer: The peer to query
*
* Get a pointer to the address from a peer record. The caller is responsible
* for making sure that the address is not deallocated.
*/
const struct sockaddr_rxrpc *rxrpc_kernel_remote_srx(const struct rxrpc_peer *peer)
{
return peer ? &peer->srx : &rxrpc_null_addr;
}
EXPORT_SYMBOL(rxrpc_kernel_remote_srx);
/**
* rxrpc_kernel_remote_addr - Get the peer transport address of a call
* @peer: The peer to query
*
* Get a pointer to the transport address from a peer record. The caller is
* responsible for making sure that the address is not deallocated.
*/
const struct sockaddr *rxrpc_kernel_remote_addr(const struct rxrpc_peer *peer)
{
return (const struct sockaddr *)
(peer ? &peer->srx.transport : &rxrpc_null_addr.transport);
}
EXPORT_SYMBOL(rxrpc_kernel_remote_addr);
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