[linux-2.6-block.git] / net / rxrpc / peer_object.c

// 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 (dhowells@redhat.com)
 */

#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 &&
		    atomic_read(&peer->usage) > 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) {
		_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_sock *rx,
				  struct rxrpc_peer *peer)
{
	struct net *net = sock_net(&rx->sk);
	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)
{
	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);
		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);

		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_sock *rx, struct rxrpc_peer *peer,
			    unsigned long hash_key)
{
	peer->hash_key = hash_key;
	rxrpc_assess_MTU_size(rx, 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_sock *rx,
					    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(rx, peer, hash_key);
	}

	_leave(" = %p", peer);
	return peer;
}

/*
 * 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_sock *rx, 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);
	peer->local = local;
	rxrpc_init_peer(rx, 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_sock *rx,
				     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(rx, 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);
			list_add_tail(&candidate->keepalive_link,
				      &rxnet->peer_keepalive_new);
		}

		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;
}

/*
 * Get a ref on a peer record.
 */
struct rxrpc_peer *rxrpc_get_peer(struct rxrpc_peer *peer)
{
	const void *here = __builtin_return_address(0);
	int n;

	n = atomic_inc_return(&peer->usage);
	trace_rxrpc_peer(peer, rxrpc_peer_got, n, here);
	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)
{
	const void *here = __builtin_return_address(0);

	if (peer) {
		int n = atomic_fetch_add_unless(&peer->usage, 1, 0);
		if (n > 0)
			trace_rxrpc_peer(peer, rxrpc_peer_got, n + 1, here);
		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_bh(&rxnet->peer_hash_lock);
	hash_del_rcu(&peer->hash_link);
	list_del_init(&peer->keepalive_link);
	spin_unlock_bh(&rxnet->peer_hash_lock);

	kfree_rcu(peer, rcu);
}

/*
 * Drop a ref on a peer record.
 */
void rxrpc_put_peer(struct rxrpc_peer *peer)
{
	const void *here = __builtin_return_address(0);
	int n;

	if (peer) {
		n = atomic_dec_return(&peer->usage);
		trace_rxrpc_peer(peer, rxrpc_peer_put, n, here);
		if (n == 0)
			__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,
			       atomic_read(&peer->usage),
			       &peer->srx.transport);
		}
	}
}

/**
 * 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);
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
be6e6707	2	/* RxRPC remote transport endpoint record management
17926a79	3	*
be6e6707	4	* Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
17926a79	5	* Written by David Howells (dhowells@redhat.com)
17926a79 DH	6	*/
17926a79 DH	7
9b6d5398 JP	8	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9b6d5398 JP	9
17926a79 DH	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>
75b54cb5	15	#include <linux/in6.h>
5a0e3ad6	16	#include <linux/slab.h>
be6e6707	17	#include <linux/hashtable.h>
17926a79 DH	18	#include <net/sock.h>
	19	#include <net/af_rxrpc.h>
	20	#include <net/ip.h>
224711df	21	#include <net/route.h>
75b54cb5	22	#include <net/ip6_route.h>
17926a79 DH	23	#include "ar-internal.h"
17926a79 DH	24
be6e6707 DH	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;
d1912747	48	#ifdef CONFIG_AF_RXRPC_IPV6
75b54cb5 DH	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;
d1912747	54	#endif
2f9f9f52 AB	55	default:
	56	WARN(1, "AF_RXRPC: Unsupported transport address family\n");
	57	return 0;
be6e6707 DH	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));
d1912747	98	#ifdef CONFIG_AF_RXRPC_IPV6
75b54cb5 DH	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));
d1912747	105	#endif
be6e6707 DH	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;
2baec2c3	120	struct rxrpc_net *rxnet = local->rxnet;
be6e6707	121
2baec2c3	122	hash_for_each_possible_rcu(rxnet->peer_hash, peer, hash_link, hash_key) {
0099dc58 DH	123	if (rxrpc_peer_cmp_key(peer, local, srx, hash_key) == 0 &&
0099dc58 DH	124	atomic_read(&peer->usage) > 0)
be6e6707	125	return peer;
be6e6707 DH	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) {
75b54cb5	142	_net("PEER %d {%pISp}", peer->debug_id, &peer->srx.transport);
be6e6707 DH	143	_leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
	144	}
	145	return peer;
	146	}
17926a79	147
224711df DH	148	/*
	149	* assess the MTU size for the network interface through which this peer is
	150	* reached
	151	*/
5e33a23b DH	152	static void rxrpc_assess_MTU_size(struct rxrpc_sock *rx,
5e33a23b DH	153	struct rxrpc_peer *peer)
224711df	154	{
5e33a23b	155	struct net *net = sock_net(&rx->sk);
75b54cb5	156	struct dst_entry *dst;
224711df	157	struct rtable *rt;
75b54cb5 DH	158	struct flowi fl;
75b54cb5 DH	159	struct flowi4 *fl4 = &fl.u.ip4;
d1912747	160	#ifdef CONFIG_AF_RXRPC_IPV6
75b54cb5	161	struct flowi6 *fl6 = &fl.u.ip6;
d1912747	162	#endif
224711df DH	163
	164	peer->if_mtu = 1500;
	165
75b54cb5 DH	166	memset(&fl, 0, sizeof(fl));
	167	switch (peer->srx.transport.family) {
	168	case AF_INET:
	169	rt = ip_route_output_ports(
5e33a23b	170	net, fl4, NULL,
75b54cb5 DH	171	peer->srx.transport.sin.sin_addr.s_addr, 0,
	172	htons(7000), htons(7001), IPPROTO_UDP, 0, 0);
	173	if (IS_ERR(rt)) {
	174	_leave(" [route err %ld]", PTR_ERR(rt));
	175	return;
	176	}
	177	dst = &rt->dst;
	178	break;
	179
d1912747	180	#ifdef CONFIG_AF_RXRPC_IPV6
75b54cb5 DH	181	case AF_INET6:
	182	fl6->flowi6_iif = LOOPBACK_IFINDEX;
	183	fl6->flowi6_scope = RT_SCOPE_UNIVERSE;
	184	fl6->flowi6_proto = IPPROTO_UDP;
	185	memcpy(&fl6->daddr, &peer->srx.transport.sin6.sin6_addr,
	186	sizeof(struct in6_addr));
	187	fl6->fl6_dport = htons(7001);
	188	fl6->fl6_sport = htons(7000);
5e33a23b	189	dst = ip6_route_output(net, NULL, fl6);
07096f61 DH	190	if (dst->error) {
07096f61 DH	191	_leave(" [route err %d]", dst->error);
75b54cb5 DH	192	return;
	193	}
	194	break;
d1912747	195	#endif
75b54cb5 DH	196
	197	default:
	198	BUG();
224711df DH	199	}
224711df DH	200
75b54cb5 DH	201	peer->if_mtu = dst_mtu(dst);
75b54cb5 DH	202	dst_release(dst);
224711df	203
a6a62b69	204	_leave(" [if_mtu %u]", peer->if_mtu);
224711df DH	205	}
224711df DH	206
17926a79	207	/*
be6e6707	208	* Allocate a peer.
17926a79	209	*/
be6e6707	210	struct rxrpc_peer rxrpc_alloc_peer(struct rxrpc_local local, gfp_t gfp)
17926a79 DH	211	{
	212	struct rxrpc_peer *peer;
	213
	214	_enter("");
	215
	216	peer = kzalloc(sizeof(struct rxrpc_peer), gfp);
	217	if (peer) {
be6e6707 DH	218	atomic_set(&peer->usage, 1);
be6e6707 DH	219	peer->local = local;
f66d7490	220	INIT_HLIST_HEAD(&peer->error_targets);
aa390bbe	221	peer->service_conns = RB_ROOT;
8496af50	222	seqlock_init(&peer->service_conn_lock);
17926a79	223	spin_lock_init(&peer->lock);
c1e15b49	224	spin_lock_init(&peer->rtt_input_lock);
17926a79	225	peer->debug_id = atomic_inc_return(&rxrpc_debug_id);
f7aec129 DH	226
	227	if (RXRPC_TX_SMSS > 2190)
	228	peer->cong_cwnd = 2;
	229	else if (RXRPC_TX_SMSS > 1095)
	230	peer->cong_cwnd = 3;
	231	else
	232	peer->cong_cwnd = 4;
be6e6707 DH	233	}
	234
	235	_leave(" = %p", peer);
	236	return peer;
	237	}
	238
248f219c DH	239	/*
	240	* Initialise peer record.
	241	*/
5e33a23b DH	242	static void rxrpc_init_peer(struct rxrpc_sock rx, struct rxrpc_peer peer,
5e33a23b DH	243	unsigned long hash_key)
248f219c	244	{
08a39685	245	peer->hash_key = hash_key;
5e33a23b	246	rxrpc_assess_MTU_size(rx, peer);
248f219c	247	peer->mtu = peer->if_mtu;
0d4b103c	248	peer->rtt_last_req = ktime_get_real();
248f219c	249
75b54cb5 DH	250	switch (peer->srx.transport.family) {
75b54cb5 DH	251	case AF_INET:
248f219c	252	peer->hdrsize = sizeof(struct iphdr);
75b54cb5	253	break;
d1912747	254	#ifdef CONFIG_AF_RXRPC_IPV6
75b54cb5 DH	255	case AF_INET6:
	256	peer->hdrsize = sizeof(struct ipv6hdr);
	257	break;
d1912747	258	#endif
75b54cb5 DH	259	default:
	260	BUG();
	261	}
	262
	263	switch (peer->srx.transport_type) {
	264	case SOCK_DGRAM:
	265	peer->hdrsize += sizeof(struct udphdr);
	266	break;
	267	default:
248f219c DH	268	BUG();
	269	}
	270
	271	peer->hdrsize += sizeof(struct rxrpc_wire_header);
	272	peer->maxdata = peer->mtu - peer->hdrsize;
	273	}
	274
be6e6707 DH	275	/*
	276	* Set up a new peer.
	277	*/
5e33a23b DH	278	static struct rxrpc_peer rxrpc_create_peer(struct rxrpc_sock rx,
5e33a23b DH	279	struct rxrpc_local *local,
be6e6707 DH	280	struct sockaddr_rxrpc *srx,
	281	unsigned long hash_key,
	282	gfp_t gfp)
	283	{
	284	struct rxrpc_peer *peer;
	285
	286	_enter("");
	287
	288	peer = rxrpc_alloc_peer(local, gfp);
	289	if (peer) {
17926a79	290	memcpy(&peer->srx, srx, sizeof(*srx));
5e33a23b	291	rxrpc_init_peer(rx, peer, hash_key);
248f219c	292	}
17926a79	293
248f219c DH	294	_leave(" = %p", peer);
	295	return peer;
	296	}
17926a79	297
248f219c	298	/*
0099dc58 DH	299	* Set up a new incoming peer. There shouldn't be any other matching peers
	300	* since we've already done a search in the list from the non-reentrant context
	301	* (the data_ready handler) that is the only place we can add new peers.
248f219c	302	*/
5e33a23b DH	303	void rxrpc_new_incoming_peer(struct rxrpc_sock rx, struct rxrpc_local local,
5e33a23b DH	304	struct rxrpc_peer *peer)
248f219c	305	{
2baec2c3	306	struct rxrpc_net *rxnet = local->rxnet;
248f219c DH	307	unsigned long hash_key;
248f219c DH	308
0099dc58 DH	309	hash_key = rxrpc_peer_hash_key(local, &peer->srx);
0099dc58 DH	310	peer->local = local;
5e33a23b	311	rxrpc_init_peer(rx, peer, hash_key);
248f219c	312
2baec2c3	313	spin_lock(&rxnet->peer_hash_lock);
0099dc58 DH	314	hash_add_rcu(rxnet->peer_hash, &peer->hash_link, hash_key);
0099dc58 DH	315	list_add_tail(&peer->keepalive_link, &rxnet->peer_keepalive_new);
2baec2c3	316	spin_unlock(&rxnet->peer_hash_lock);
17926a79 DH	317	}
	318
	319	/*
	320	* obtain a remote transport endpoint for the specified address
	321	*/
5e33a23b DH	322	struct rxrpc_peer rxrpc_lookup_peer(struct rxrpc_sock rx,
5e33a23b DH	323	struct rxrpc_local *local,
be6e6707	324	struct sockaddr_rxrpc *srx, gfp_t gfp)
17926a79 DH	325	{
17926a79 DH	326	struct rxrpc_peer peer, candidate;
2baec2c3	327	struct rxrpc_net *rxnet = local->rxnet;
be6e6707	328	unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
17926a79	329
75b54cb5	330	_enter("{%pISp}", &srx->transport);
17926a79 DH	331
17926a79 DH	332	/* search the peer list first */
be6e6707 DH	333	rcu_read_lock();
	334	peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
	335	if (peer && !rxrpc_get_peer_maybe(peer))
	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	*/
5e33a23b	343	candidate = rxrpc_create_peer(rx, local, srx, hash_key, gfp);
be6e6707 DH	344	if (!candidate) {
	345	_leave(" = NULL [nomem]");
	346	return NULL;
	347	}
17926a79	348
2baec2c3	349	spin_lock_bh(&rxnet->peer_hash_lock);
17926a79	350
be6e6707 DH	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))
	354	peer = NULL;
ace45bec	355	if (!peer) {
2baec2c3	356	hash_add_rcu(rxnet->peer_hash,
be6e6707	357	&candidate->hash_link, hash_key);
330bdcfa DH	358	list_add_tail(&candidate->keepalive_link,
330bdcfa DH	359	&rxnet->peer_keepalive_new);
ace45bec	360	}
17926a79	361
2baec2c3	362	spin_unlock_bh(&rxnet->peer_hash_lock);
17926a79	363
be6e6707 DH	364	if (peer)
	365	kfree(candidate);
	366	else
	367	peer = candidate;
	368	}
17926a79	369
75b54cb5	370	_net("PEER %d {%pISp}", peer->debug_id, &peer->srx.transport);
17926a79	371
be6e6707	372	_leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
17926a79	373	return peer;
17926a79 DH	374	}
	375
	376	/*
1159d4b4	377	* Get a ref on a peer record.
17926a79	378	*/
1159d4b4 DH	379	struct rxrpc_peer rxrpc_get_peer(struct rxrpc_peer peer)
	380	{
	381	const void *here = __builtin_return_address(0);
	382	int n;
	383
	384	n = atomic_inc_return(&peer->usage);
	385	trace_rxrpc_peer(peer, rxrpc_peer_got, n, here);
	386	return peer;
	387	}
	388
	389	/*
	390	* Get a ref on a peer record unless its usage has already reached 0.
	391	*/
	392	struct rxrpc_peer rxrpc_get_peer_maybe(struct rxrpc_peer peer)
	393	{
	394	const void *here = __builtin_return_address(0);
	395
	396	if (peer) {
bfc18e38	397	int n = atomic_fetch_add_unless(&peer->usage, 1, 0);
1159d4b4 DH	398	if (n > 0)
	399	trace_rxrpc_peer(peer, rxrpc_peer_got, n + 1, here);
	400	else
	401	peer = NULL;
	402	}
	403	return peer;
	404	}
	405
1159d4b4 DH	406	/*
	407	* Discard a peer record.
	408	*/
	409	static void __rxrpc_put_peer(struct rxrpc_peer *peer)
17926a79	410	{
2baec2c3 DH	411	struct rxrpc_net *rxnet = peer->local->rxnet;
2baec2c3 DH	412
f66d7490	413	ASSERT(hlist_empty(&peer->error_targets));
17926a79	414
2baec2c3	415	spin_lock_bh(&rxnet->peer_hash_lock);
be6e6707	416	hash_del_rcu(&peer->hash_link);
330bdcfa	417	list_del_init(&peer->keepalive_link);
2baec2c3	418	spin_unlock_bh(&rxnet->peer_hash_lock);
17926a79	419
be6e6707	420	kfree_rcu(peer, rcu);
17926a79	421	}
8324f0bc	422
1159d4b4 DH	423	/*
	424	* Drop a ref on a peer record.
	425	*/
	426	void rxrpc_put_peer(struct rxrpc_peer *peer)
	427	{
	428	const void *here = __builtin_return_address(0);
	429	int n;
	430
	431	if (peer) {
	432	n = atomic_dec_return(&peer->usage);
	433	trace_rxrpc_peer(peer, rxrpc_peer_put, n, here);
	434	if (n == 0)
	435	__rxrpc_put_peer(peer);
	436	}
	437	}
	438
17226f12 DH	439	/*
	440	* Make sure all peer records have been discarded.
	441	*/
	442	void rxrpc_destroy_all_peers(struct rxrpc_net *rxnet)
	443	{
	444	struct rxrpc_peer *peer;
	445	int i;
	446
	447	for (i = 0; i < HASH_SIZE(rxnet->peer_hash); i++) {
	448	if (hlist_empty(&rxnet->peer_hash[i]))
	449	continue;
	450
	451	hlist_for_each_entry(peer, &rxnet->peer_hash[i], hash_link) {
	452	pr_err("Leaked peer %u {%u} %pISp\n",
	453	peer->debug_id,
	454	atomic_read(&peer->usage),
	455	&peer->srx.transport);
	456	}
	457	}
	458	}
	459
8324f0bc DH	460	/**
	461	* rxrpc_kernel_get_peer - Get the peer address of a call
	462	* @sock: The socket on which the call is in progress.
	463	* @call: The call to query
	464	* @_srx: Where to place the result
	465	*
	466	* Get the address of the remote peer in a call.
	467	*/
	468	void rxrpc_kernel_get_peer(struct socket sock, struct rxrpc_call call,
	469	struct sockaddr_rxrpc *_srx)
	470	{
	471	*_srx = call->peer->srx;
	472	}
	473	EXPORT_SYMBOL(rxrpc_kernel_get_peer);
f4d15fb6 DH	474
	475	/**
	476	* rxrpc_kernel_get_rtt - Get a call's peer RTT
	477	* @sock: The socket on which the call is in progress.
	478	* @call: The call to query
	479	*
	480	* Get the call's peer RTT.
	481	*/
	482	u64 rxrpc_kernel_get_rtt(struct socket sock, struct rxrpc_call call)
	483	{
	484	return call->peer->rtt;
	485	}
	486	EXPORT_SYMBOL(rxrpc_kernel_get_rtt);