[thirdparty/linux.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"

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;
	if (peer->max_data < peer->if_mtu - peer->hdrsize) {
		trace_rxrpc_pmtud_reduce(peer, 0, peer->if_mtu - peer->hdrsize,
					 rxrpc_pmtud_reduce_route);
		peer->max_data = peer->if_mtu - peer->hdrsize;
	}

	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);
	peer->hdrsize += dst->header_len + dst->trailer_len;
	peer->tx_seg_max = dst->dev->gso_max_segs;
	dst_release(dst);

	peer->max_data		= umin(RXRPC_JUMBO(1), peer->if_mtu - peer->hdrsize);
	peer->pmtud_good	= 500;
	peer->pmtud_bad		= peer->if_mtu - peer->hdrsize + 1;
	peer->pmtud_trial	= umin(peer->max_data, peer->pmtud_bad - 1);
	peer->pmtud_pending	= true;

	_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);
		peer->debug_id = atomic_inc_return(&rxrpc_debug_id);
		peer->recent_srtt_us = UINT_MAX;
		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;


	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->max_data = peer->if_mtu - peer->hdrsize;

	rxrpc_assess_MTU_size(local, peer);
}

/*
 * 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.
 * Called with interrupts disabled.
 */
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_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, 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_bh(&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_bh(&rxnet->peer_hash_lock);
	hash_del_rcu(&peer->hash_link);
	list_del_init(&peer->keepalive_link);
	spin_unlock_bh(&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 %x {%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.
 *
 * Return: The call's peer record.
 */
struct rxrpc_peer *rxrpc_kernel_get_call_peer(struct socket *sock, struct rxrpc_call *call)
{
	return rxrpc_get_peer(call->peer, rxrpc_peer_get_application);
}
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.
 *
 * Return: The RTT in uS or %UINT_MAX if we have no samples.
 */
unsigned int rxrpc_kernel_get_srtt(const struct rxrpc_peer *peer)
{
	return READ_ONCE(peer->recent_srtt_us);
}
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.  A fake address will be
 * substituted if %peer in NULL.
 *
 * Return: The rxrpc address record or a fake record.
 */
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.  A fake
 * address will be substituted if %peer in NULL.
 *
 * Return: The transport address record or a fake record.
 */
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);

/**
 * rxrpc_kernel_set_peer_data - Set app-specific data on a peer.
 * @peer: The peer to alter
 * @app_data: The data to set
 *
 * Set the app-specific data on a peer.  AF_RXRPC makes no effort to retain
 * anything the data might refer to.
 *
 * Return: The previous app_data.
 */
unsigned long rxrpc_kernel_set_peer_data(struct rxrpc_peer *peer, unsigned long app_data)
{
	return xchg(&peer->app_data, app_data);
}
EXPORT_SYMBOL(rxrpc_kernel_set_peer_data);

/**
 * rxrpc_kernel_get_peer_data - Get app-specific data from a peer.
 * @peer: The peer to query
 *
 * Retrieve the app-specific data from a peer.
 *
 * Return: The peer's app data.
 */
unsigned long rxrpc_kernel_get_peer_data(const struct rxrpc_peer *peer)
{
	return peer->app_data;
}
EXPORT_SYMBOL(rxrpc_kernel_get_peer_data);
Commit	Line	Data
	1	// SPDX-License-Identifier: GPL-2.0-or-later
	2	/* RxRPC remote transport endpoint record management
	3	*
	4	* Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
	5	* Written by David Howells (dhowells@redhat.com)
	6	*/
	7
	8	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
	9
	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>
	15	#include <linux/in6.h>
	16	#include <linux/slab.h>
	17	#include <linux/hashtable.h>
	18	#include <net/sock.h>
	19	#include <net/af_rxrpc.h>
	20	#include <net/ip.h>
	21	#include <net/route.h>
	22	#include <net/ip6_route.h>
	23	#include "ar-internal.h"
	24
	25	static const struct sockaddr_rxrpc rxrpc_null_addr;
	26
	27	/*
	28	* Hash a peer key.
	29	*/
	30	static unsigned long rxrpc_peer_hash_key(struct rxrpc_local *local,
	31	const struct sockaddr_rxrpc *srx)
	32	{
	33	const u16 *p;
	34	unsigned int i, size;
	35	unsigned long hash_key;
	36
	37	_enter("");
	38
	39	hash_key = (unsigned long)local / __alignof__(*local);
	40	hash_key += srx->transport_type;
	41	hash_key += srx->transport_len;
	42	hash_key += srx->transport.family;
	43
	44	switch (srx->transport.family) {
	45	case AF_INET:
	46	hash_key += (u16 __force)srx->transport.sin.sin_port;
	47	size = sizeof(srx->transport.sin.sin_addr);
	48	p = (u16 *)&srx->transport.sin.sin_addr;
	49	break;
	50	#ifdef CONFIG_AF_RXRPC_IPV6
	51	case AF_INET6:
	52	hash_key += (u16 __force)srx->transport.sin.sin_port;
	53	size = sizeof(srx->transport.sin6.sin6_addr);
	54	p = (u16 *)&srx->transport.sin6.sin6_addr;
	55	break;
	56	#endif
	57	default:
	58	WARN(1, "AF_RXRPC: Unsupported transport address family\n");
	59	return 0;
	60	}
	61
	62	/* Step through the peer address in 16-bit portions for speed */
	63	for (i = 0; i < size; i += sizeof(*p), p++)
	64	hash_key += *p;
	65
	66	_leave(" 0x%lx", hash_key);
	67	return hash_key;
	68	}
	69
	70	/*
	71	* Compare a peer to a key. Return -ve, 0 or +ve to indicate less than, same
	72	* or greater than.
	73	*
	74	* Unfortunately, the primitives in linux/hashtable.h don't allow for sorted
	75	* buckets and mid-bucket insertion, so we don't make full use of this
	76	* information at this point.
	77	*/
	78	static long rxrpc_peer_cmp_key(const struct rxrpc_peer *peer,
	79	struct rxrpc_local *local,
	80	const struct sockaddr_rxrpc *srx,
	81	unsigned long hash_key)
	82	{
	83	long diff;
	84
	85	diff = ((peer->hash_key - hash_key) ?:
	86	((unsigned long)peer->local - (unsigned long)local) ?:
	87	(peer->srx.transport_type - srx->transport_type) ?:
	88	(peer->srx.transport_len - srx->transport_len) ?:
	89	(peer->srx.transport.family - srx->transport.family));
	90	if (diff != 0)
	91	return diff;
	92
	93	switch (srx->transport.family) {
	94	case AF_INET:
	95	return ((u16 __force)peer->srx.transport.sin.sin_port -
	96	(u16 __force)srx->transport.sin.sin_port) ?:
	97	memcmp(&peer->srx.transport.sin.sin_addr,
	98	&srx->transport.sin.sin_addr,
	99	sizeof(struct in_addr));
	100	#ifdef CONFIG_AF_RXRPC_IPV6
	101	case AF_INET6:
	102	return ((u16 __force)peer->srx.transport.sin6.sin6_port -
	103	(u16 __force)srx->transport.sin6.sin6_port) ?:
	104	memcmp(&peer->srx.transport.sin6.sin6_addr,
	105	&srx->transport.sin6.sin6_addr,
	106	sizeof(struct in6_addr));
	107	#endif
	108	default:
	109	BUG();
	110	}
	111	}
	112
	113	/*
	114	* Look up a remote transport endpoint for the specified address using RCU.
	115	*/
	116	static struct rxrpc_peer *__rxrpc_lookup_peer_rcu(
	117	struct rxrpc_local *local,
	118	const struct sockaddr_rxrpc *srx,
	119	unsigned long hash_key)
	120	{
	121	struct rxrpc_peer *peer;
	122	struct rxrpc_net *rxnet = local->rxnet;
	123
	124	hash_for_each_possible_rcu(rxnet->peer_hash, peer, hash_link, hash_key) {
	125	if (rxrpc_peer_cmp_key(peer, local, srx, hash_key) == 0 &&
	126	refcount_read(&peer->ref) > 0)
	127	return peer;
	128	}
	129
	130	return NULL;
	131	}
	132
	133	/*
	134	* Look up a remote transport endpoint for the specified address using RCU.
	135	*/
	136	struct rxrpc_peer rxrpc_lookup_peer_rcu(struct rxrpc_local local,
	137	const struct sockaddr_rxrpc *srx)
	138	{
	139	struct rxrpc_peer *peer;
	140	unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
	141
	142	peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
	143	if (peer)
	144	_leave(" = %p {u=%d}", peer, refcount_read(&peer->ref));
	145	return peer;
	146	}
	147
	148	/*
	149	* assess the MTU size for the network interface through which this peer is
	150	* reached
	151	*/
	152	static void rxrpc_assess_MTU_size(struct rxrpc_local *local,
	153	struct rxrpc_peer *peer)
	154	{
	155	struct net *net = local->net;
	156	struct dst_entry *dst;
	157	struct rtable *rt;
	158	struct flowi fl;
	159	struct flowi4 *fl4 = &fl.u.ip4;
	160	#ifdef CONFIG_AF_RXRPC_IPV6
	161	struct flowi6 *fl6 = &fl.u.ip6;
	162	#endif
	163
	164	peer->if_mtu = 1500;
	165	if (peer->max_data < peer->if_mtu - peer->hdrsize) {
	166	trace_rxrpc_pmtud_reduce(peer, 0, peer->if_mtu - peer->hdrsize,
	167	rxrpc_pmtud_reduce_route);
	168	peer->max_data = peer->if_mtu - peer->hdrsize;
	169	}
	170
	171	memset(&fl, 0, sizeof(fl));
	172	switch (peer->srx.transport.family) {
	173	case AF_INET:
	174	rt = ip_route_output_ports(
	175	net, fl4, NULL,
	176	peer->srx.transport.sin.sin_addr.s_addr, 0,
	177	htons(7000), htons(7001), IPPROTO_UDP, 0, 0);
	178	if (IS_ERR(rt)) {
	179	_leave(" [route err %ld]", PTR_ERR(rt));
	180	return;
	181	}
	182	dst = &rt->dst;
	183	break;
	184
	185	#ifdef CONFIG_AF_RXRPC_IPV6
	186	case AF_INET6:
	187	fl6->flowi6_iif = LOOPBACK_IFINDEX;
	188	fl6->flowi6_scope = RT_SCOPE_UNIVERSE;
	189	fl6->flowi6_proto = IPPROTO_UDP;
	190	memcpy(&fl6->daddr, &peer->srx.transport.sin6.sin6_addr,
	191	sizeof(struct in6_addr));
	192	fl6->fl6_dport = htons(7001);
	193	fl6->fl6_sport = htons(7000);
	194	dst = ip6_route_output(net, NULL, fl6);
	195	if (dst->error) {
	196	_leave(" [route err %d]", dst->error);
	197	return;
	198	}
	199	break;
	200	#endif
	201
	202	default:
	203	BUG();
	204	}
	205
	206	peer->if_mtu = dst_mtu(dst);
	207	peer->hdrsize += dst->header_len + dst->trailer_len;
	208	peer->tx_seg_max = dst->dev->gso_max_segs;
	209	dst_release(dst);
	210
	211	peer->max_data = umin(RXRPC_JUMBO(1), peer->if_mtu - peer->hdrsize);
	212	peer->pmtud_good = 500;
	213	peer->pmtud_bad = peer->if_mtu - peer->hdrsize + 1;
	214	peer->pmtud_trial = umin(peer->max_data, peer->pmtud_bad - 1);
	215	peer->pmtud_pending = true;
	216
	217	_leave(" [if_mtu %u]", peer->if_mtu);
	218	}
	219
	220	/*
	221	* Allocate a peer.
	222	*/
	223	struct rxrpc_peer rxrpc_alloc_peer(struct rxrpc_local local, gfp_t gfp,
	224	enum rxrpc_peer_trace why)
	225	{
	226	struct rxrpc_peer *peer;
	227
	228	_enter("");
	229
	230	peer = kzalloc(sizeof(struct rxrpc_peer), gfp);
	231	if (peer) {
	232	refcount_set(&peer->ref, 1);
	233	peer->local = rxrpc_get_local(local, rxrpc_local_get_peer);
	234	INIT_HLIST_HEAD(&peer->error_targets);
	235	peer->service_conns = RB_ROOT;
	236	seqlock_init(&peer->service_conn_lock);
	237	spin_lock_init(&peer->lock);
	238	peer->debug_id = atomic_inc_return(&rxrpc_debug_id);
	239	peer->recent_srtt_us = UINT_MAX;
	240	peer->cong_ssthresh = RXRPC_TX_MAX_WINDOW;
	241	trace_rxrpc_peer(peer->debug_id, 1, why);
	242	}
	243
	244	_leave(" = %p", peer);
	245	return peer;
	246	}
	247
	248	/*
	249	* Initialise peer record.
	250	*/
	251	static void rxrpc_init_peer(struct rxrpc_local local, struct rxrpc_peer peer,
	252	unsigned long hash_key)
	253	{
	254	peer->hash_key = hash_key;
	255
	256
	257	switch (peer->srx.transport.family) {
	258	case AF_INET:
	259	peer->hdrsize = sizeof(struct iphdr);
	260	break;
	261	#ifdef CONFIG_AF_RXRPC_IPV6
	262	case AF_INET6:
	263	peer->hdrsize = sizeof(struct ipv6hdr);
	264	break;
	265	#endif
	266	default:
	267	BUG();
	268	}
	269
	270	switch (peer->srx.transport_type) {
	271	case SOCK_DGRAM:
	272	peer->hdrsize += sizeof(struct udphdr);
	273	break;
	274	default:
	275	BUG();
	276	}
	277
	278	peer->hdrsize += sizeof(struct rxrpc_wire_header);
	279	peer->max_data = peer->if_mtu - peer->hdrsize;
	280
	281	rxrpc_assess_MTU_size(local, peer);
	282	}
	283
	284	/*
	285	* Set up a new peer.
	286	*/
	287	static struct rxrpc_peer rxrpc_create_peer(struct rxrpc_local local,
	288	struct sockaddr_rxrpc *srx,
	289	unsigned long hash_key,
	290	gfp_t gfp)
	291	{
	292	struct rxrpc_peer *peer;
	293
	294	_enter("");
	295
	296	peer = rxrpc_alloc_peer(local, gfp, rxrpc_peer_new_client);
	297	if (peer) {
	298	memcpy(&peer->srx, srx, sizeof(*srx));
	299	rxrpc_init_peer(local, peer, hash_key);
	300	}
	301
	302	_leave(" = %p", peer);
	303	return peer;
	304	}
	305
	306	static void rxrpc_free_peer(struct rxrpc_peer *peer)
	307	{
	308	trace_rxrpc_peer(peer->debug_id, 0, rxrpc_peer_free);
	309	rxrpc_put_local(peer->local, rxrpc_local_put_peer);
	310	kfree_rcu(peer, rcu);
	311	}
	312
	313	/*
	314	* Set up a new incoming peer. There shouldn't be any other matching peers
	315	* since we've already done a search in the list from the non-reentrant context
	316	* (the data_ready handler) that is the only place we can add new peers.
	317	* Called with interrupts disabled.
	318	*/
	319	void rxrpc_new_incoming_peer(struct rxrpc_local local, struct rxrpc_peer peer)
	320	{
	321	struct rxrpc_net *rxnet = local->rxnet;
	322	unsigned long hash_key;
	323
	324	hash_key = rxrpc_peer_hash_key(local, &peer->srx);
	325	rxrpc_init_peer(local, peer, hash_key);
	326
	327	spin_lock(&rxnet->peer_hash_lock);
	328	hash_add_rcu(rxnet->peer_hash, &peer->hash_link, hash_key);
	329	list_add_tail(&peer->keepalive_link, &rxnet->peer_keepalive_new);
	330	spin_unlock(&rxnet->peer_hash_lock);
	331	}
	332
	333	/*
	334	* obtain a remote transport endpoint for the specified address
	335	*/
	336	struct rxrpc_peer rxrpc_lookup_peer(struct rxrpc_local local,
	337	struct sockaddr_rxrpc *srx, gfp_t gfp)
	338	{
	339	struct rxrpc_peer peer, candidate;
	340	struct rxrpc_net *rxnet = local->rxnet;
	341	unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
	342
	343	_enter("{%pISp}", &srx->transport);
	344
	345	/* search the peer list first */
	346	rcu_read_lock();
	347	peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
	348	if (peer && !rxrpc_get_peer_maybe(peer, rxrpc_peer_get_lookup_client))
	349	peer = NULL;
	350	rcu_read_unlock();
	351
	352	if (!peer) {
	353	/* The peer is not yet present in hash - create a candidate
	354	* for a new record and then redo the search.
	355	*/
	356	candidate = rxrpc_create_peer(local, srx, hash_key, gfp);
	357	if (!candidate) {
	358	_leave(" = NULL [nomem]");
	359	return NULL;
	360	}
	361
	362	spin_lock_bh(&rxnet->peer_hash_lock);
	363
	364	/* Need to check that we aren't racing with someone else */
	365	peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
	366	if (peer && !rxrpc_get_peer_maybe(peer, rxrpc_peer_get_lookup_client))
	367	peer = NULL;
	368	if (!peer) {
	369	hash_add_rcu(rxnet->peer_hash,
	370	&candidate->hash_link, hash_key);
	371	list_add_tail(&candidate->keepalive_link,
	372	&rxnet->peer_keepalive_new);
	373	}
	374
	375	spin_unlock_bh(&rxnet->peer_hash_lock);
	376
	377	if (peer)
	378	rxrpc_free_peer(candidate);
	379	else
	380	peer = candidate;
	381	}
	382
	383	_leave(" = %p {u=%d}", peer, refcount_read(&peer->ref));
	384	return peer;
	385	}
	386
	387	/*
	388	* Get a ref on a peer record.
	389	*/
	390	struct rxrpc_peer rxrpc_get_peer(struct rxrpc_peer peer, enum rxrpc_peer_trace why)
	391	{
	392	int r;
	393
	394	__refcount_inc(&peer->ref, &r);
	395	trace_rxrpc_peer(peer->debug_id, r + 1, why);
	396	return peer;
	397	}
	398
	399	/*
	400	* Get a ref on a peer record unless its usage has already reached 0.
	401	*/
	402	struct rxrpc_peer rxrpc_get_peer_maybe(struct rxrpc_peer peer,
	403	enum rxrpc_peer_trace why)
	404	{
	405	int r;
	406
	407	if (peer) {
	408	if (__refcount_inc_not_zero(&peer->ref, &r))
	409	trace_rxrpc_peer(peer->debug_id, r + 1, why);
	410	else
	411	peer = NULL;
	412	}
	413	return peer;
	414	}
	415
	416	/*
	417	* Discard a peer record.
	418	*/
	419	static void __rxrpc_put_peer(struct rxrpc_peer *peer)
	420	{
	421	struct rxrpc_net *rxnet = peer->local->rxnet;
	422
	423	ASSERT(hlist_empty(&peer->error_targets));
	424
	425	spin_lock_bh(&rxnet->peer_hash_lock);
	426	hash_del_rcu(&peer->hash_link);
	427	list_del_init(&peer->keepalive_link);
	428	spin_unlock_bh(&rxnet->peer_hash_lock);
	429
	430	rxrpc_free_peer(peer);
	431	}
	432
	433	/*
	434	* Drop a ref on a peer record.
	435	*/
	436	void rxrpc_put_peer(struct rxrpc_peer *peer, enum rxrpc_peer_trace why)
	437	{
	438	unsigned int debug_id;
	439	bool dead;
	440	int r;
	441
	442	if (peer) {
	443	debug_id = peer->debug_id;
	444	dead = __refcount_dec_and_test(&peer->ref, &r);
	445	trace_rxrpc_peer(debug_id, r - 1, why);
	446	if (dead)
	447	__rxrpc_put_peer(peer);
	448	}
	449	}
	450
	451	/*
	452	* Make sure all peer records have been discarded.
	453	*/
	454	void rxrpc_destroy_all_peers(struct rxrpc_net *rxnet)
	455	{
	456	struct rxrpc_peer *peer;
	457	int i;
	458
	459	for (i = 0; i < HASH_SIZE(rxnet->peer_hash); i++) {
	460	if (hlist_empty(&rxnet->peer_hash[i]))
	461	continue;
	462
	463	hlist_for_each_entry(peer, &rxnet->peer_hash[i], hash_link) {
	464	pr_err("Leaked peer %x {%u} %pISp\n",
	465	peer->debug_id,
	466	refcount_read(&peer->ref),
	467	&peer->srx.transport);
	468	}
	469	}
	470	}
	471
	472	/**
	473	* rxrpc_kernel_get_call_peer - Get the peer address of a call
	474	* @sock: The socket on which the call is in progress.
	475	* @call: The call to query
	476	*
	477	* Get a record for the remote peer in a call.
	478	*
	479	* Return: The call's peer record.
	480	*/
	481	struct rxrpc_peer rxrpc_kernel_get_call_peer(struct socket sock, struct rxrpc_call *call)
	482	{
	483	return rxrpc_get_peer(call->peer, rxrpc_peer_get_application);
	484	}
	485	EXPORT_SYMBOL(rxrpc_kernel_get_call_peer);
	486
	487	/**
	488	* rxrpc_kernel_get_srtt - Get a call's peer smoothed RTT
	489	* @peer: The peer to query
	490	*
	491	* Get the call's peer smoothed RTT.
	492	*
	493	* Return: The RTT in uS or %UINT_MAX if we have no samples.
	494	*/
	495	unsigned int rxrpc_kernel_get_srtt(const struct rxrpc_peer *peer)
	496	{
	497	return READ_ONCE(peer->recent_srtt_us);
	498	}
	499	EXPORT_SYMBOL(rxrpc_kernel_get_srtt);
	500
	501	/**
	502	* rxrpc_kernel_remote_srx - Get the address of a peer
	503	* @peer: The peer to query
	504	*
	505	* Get a pointer to the address from a peer record. The caller is responsible
	506	* for making sure that the address is not deallocated. A fake address will be
	507	* substituted if %peer in NULL.
	508	*
	509	* Return: The rxrpc address record or a fake record.
	510	*/
	511	const struct sockaddr_rxrpc rxrpc_kernel_remote_srx(const struct rxrpc_peer peer)
	512	{
	513	return peer ? &peer->srx : &rxrpc_null_addr;
	514	}
	515	EXPORT_SYMBOL(rxrpc_kernel_remote_srx);
	516
	517	/**
	518	* rxrpc_kernel_remote_addr - Get the peer transport address of a call
	519	* @peer: The peer to query
	520	*
	521	* Get a pointer to the transport address from a peer record. The caller is
	522	* responsible for making sure that the address is not deallocated. A fake
	523	* address will be substituted if %peer in NULL.
	524	*
	525	* Return: The transport address record or a fake record.
	526	*/
	527	const struct sockaddr rxrpc_kernel_remote_addr(const struct rxrpc_peer peer)
	528	{
	529	return (const struct sockaddr *)
	530	(peer ? &peer->srx.transport : &rxrpc_null_addr.transport);
	531	}
	532	EXPORT_SYMBOL(rxrpc_kernel_remote_addr);
	533
	534	/**
	535	* rxrpc_kernel_set_peer_data - Set app-specific data on a peer.
	536	* @peer: The peer to alter
	537	* @app_data: The data to set
	538	*
	539	* Set the app-specific data on a peer. AF_RXRPC makes no effort to retain
	540	* anything the data might refer to.
	541	*
	542	* Return: The previous app_data.
	543	*/
	544	unsigned long rxrpc_kernel_set_peer_data(struct rxrpc_peer *peer, unsigned long app_data)
	545	{
	546	return xchg(&peer->app_data, app_data);
	547	}
	548	EXPORT_SYMBOL(rxrpc_kernel_set_peer_data);
	549
	550	/**
	551	* rxrpc_kernel_get_peer_data - Get app-specific data from a peer.
	552	* @peer: The peer to query
	553	*
	554	* Retrieve the app-specific data from a peer.
	555	*
	556	* Return: The peer's app data.
	557	*/
	558	unsigned long rxrpc_kernel_get_peer_data(const struct rxrpc_peer *peer)
	559	{
	560	return peer->app_data;
	561	}
	562	EXPORT_SYMBOL(rxrpc_kernel_get_peer_data);