[deliverable/linux.git] / net / rxrpc / peer_object.c

/* 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/slab.h>
#include <linux/hashtable.h>
#include <net/sock.h>
#include <net/af_rxrpc.h>
#include <net/ip.h>
#include <net/route.h>
#include "ar-internal.h"

static DEFINE_HASHTABLE(rxrpc_peer_hash, 10);
static DEFINE_SPINLOCK(rxrpc_peer_hash_lock);

/*
 * 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;
	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));
	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;

	hash_for_each_possible_rcu(rxrpc_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) {
		switch (srx->transport.family) {
		case AF_INET:
			_net("PEER %d {%d,%u,%pI4+%hu}",
			     peer->debug_id,
			     peer->srx.transport_type,
			     peer->srx.transport.family,
			     &peer->srx.transport.sin.sin_addr,
			     ntohs(peer->srx.transport.sin.sin_port));
			break;
		}

		_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 rtable *rt;
	struct flowi4 fl4;

	peer->if_mtu = 1500;

	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;
	}

	peer->if_mtu = dst_mtu(&rt->dst);
	dst_release(&rt->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);
	}

	_leave(" = %p", peer);
	return 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);
	if (peer) {
		peer->hash_key = hash_key;
		memcpy(&peer->srx, srx, sizeof(*srx));

		rxrpc_assess_MTU_size(peer);
		peer->mtu = peer->if_mtu;

		if (srx->transport.family == AF_INET) {
			peer->hdrsize = sizeof(struct iphdr);
			switch (srx->transport_type) {
			case SOCK_DGRAM:
				peer->hdrsize += sizeof(struct udphdr);
				break;
			default:
				BUG();
				break;
			}
		} else {
			BUG();
		}

		peer->hdrsize += sizeof(struct rxrpc_wire_header);
		peer->maxdata = peer->mtu - peer->hdrsize;
	}

	_leave(" = %p", peer);
	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;
	unsigned long hash_key = rxrpc_peer_hash_key(local, srx);

	_enter("{%d,%d,%pI4+%hu}",
	       srx->transport_type,
	       srx->transport_len,
	       &srx->transport.sin.sin_addr,
	       ntohs(srx->transport.sin.sin_port));

	/* 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(&rxrpc_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(rxrpc_peer_hash,
				     &candidate->hash_link, hash_key);

		spin_unlock(&rxrpc_peer_hash_lock);

		if (peer)
			kfree(candidate);
		else
			peer = candidate;
	}

	_net("PEER %d {%d,%pI4+%hu}",
	     peer->debug_id,
	     peer->srx.transport_type,
	     &peer->srx.transport.sin.sin_addr,
	     ntohs(peer->srx.transport.sin.sin_port));

	_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)
{
	ASSERT(hlist_empty(&peer->error_targets));

	spin_lock(&rxrpc_peer_hash_lock);
	hash_del_rcu(&peer->hash_link);
	spin_unlock(&rxrpc_peer_hash_lock);

	kfree_rcu(peer, rcu);
}
Commit	Line	Data
be6e6707	1	/* RxRPC remote transport endpoint record management
17926a79	2	*
be6e6707	3	* Copyright (C) 2007, 2016 Red Hat, Inc. All Rights Reserved.
17926a79 DH	4	* Written by David Howells (dhowells@redhat.com)
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the License, or (at your option) any later version.
	10	*/
	11
9b6d5398 JP	12	#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9b6d5398 JP	13
17926a79 DH	14	#include <linux/module.h>
	15	#include <linux/net.h>
	16	#include <linux/skbuff.h>
	17	#include <linux/udp.h>
	18	#include <linux/in.h>
5a0e3ad6	19	#include <linux/slab.h>
be6e6707	20	#include <linux/hashtable.h>
17926a79 DH	21	#include <net/sock.h>
	22	#include <net/af_rxrpc.h>
	23	#include <net/ip.h>
224711df	24	#include <net/route.h>
17926a79 DH	25	#include "ar-internal.h"
17926a79 DH	26
be6e6707 DH	27	static DEFINE_HASHTABLE(rxrpc_peer_hash, 10);
be6e6707 DH	28	static DEFINE_SPINLOCK(rxrpc_peer_hash_lock);
17926a79	29
be6e6707 DH	30	/*
	31	* Hash a peer key.
	32	*/
	33	static unsigned long rxrpc_peer_hash_key(struct rxrpc_local *local,
	34	const struct sockaddr_rxrpc *srx)
	35	{
	36	const u16 *p;
	37	unsigned int i, size;
	38	unsigned long hash_key;
	39
	40	_enter("");
	41
	42	hash_key = (unsigned long)local / __alignof__(*local);
	43	hash_key += srx->transport_type;
	44	hash_key += srx->transport_len;
	45	hash_key += srx->transport.family;
	46
	47	switch (srx->transport.family) {
	48	case AF_INET:
	49	hash_key += (u16 __force)srx->transport.sin.sin_port;
	50	size = sizeof(srx->transport.sin.sin_addr);
	51	p = (u16 *)&srx->transport.sin.sin_addr;
	52	break;
2f9f9f52 AB	53	default:
	54	WARN(1, "AF_RXRPC: Unsupported transport address family\n");
	55	return 0;
be6e6707 DH	56	}
	57
	58	/* Step through the peer address in 16-bit portions for speed */
	59	for (i = 0; i < size; i += sizeof(*p), p++)
	60	hash_key += *p;
	61
	62	_leave(" 0x%lx", hash_key);
	63	return hash_key;
	64	}
	65
	66	/*
	67	* Compare a peer to a key. Return -ve, 0 or +ve to indicate less than, same
	68	* or greater than.
	69	*
	70	* Unfortunately, the primitives in linux/hashtable.h don't allow for sorted
	71	* buckets and mid-bucket insertion, so we don't make full use of this
	72	* information at this point.
	73	*/
	74	static long rxrpc_peer_cmp_key(const struct rxrpc_peer *peer,
	75	struct rxrpc_local *local,
	76	const struct sockaddr_rxrpc *srx,
	77	unsigned long hash_key)
	78	{
	79	long diff;
	80
	81	diff = ((peer->hash_key - hash_key) ?:
	82	((unsigned long)peer->local - (unsigned long)local) ?:
	83	(peer->srx.transport_type - srx->transport_type) ?:
	84	(peer->srx.transport_len - srx->transport_len) ?:
	85	(peer->srx.transport.family - srx->transport.family));
	86	if (diff != 0)
	87	return diff;
	88
	89	switch (srx->transport.family) {
	90	case AF_INET:
	91	return ((u16 __force)peer->srx.transport.sin.sin_port -
	92	(u16 __force)srx->transport.sin.sin_port) ?:
	93	memcmp(&peer->srx.transport.sin.sin_addr,
	94	&srx->transport.sin.sin_addr,
	95	sizeof(struct in_addr));
	96	default:
	97	BUG();
	98	}
	99	}
	100
	101	/*
	102	* Look up a remote transport endpoint for the specified address using RCU.
	103	*/
	104	static struct rxrpc_peer *__rxrpc_lookup_peer_rcu(
	105	struct rxrpc_local *local,
	106	const struct sockaddr_rxrpc *srx,
	107	unsigned long hash_key)
	108	{
	109	struct rxrpc_peer *peer;
	110
	111	hash_for_each_possible_rcu(rxrpc_peer_hash, peer, hash_link, hash_key) {
	112	if (rxrpc_peer_cmp_key(peer, local, srx, hash_key) == 0) {
	113	if (atomic_read(&peer->usage) == 0)
	114	return NULL;
	115	return peer;
	116	}
	117	}
	118
	119	return NULL;
120	}
121
122	/*
123	* Look up a remote transport endpoint for the specified address using RCU.
124	*/
125	struct rxrpc_peer rxrpc_lookup_peer_rcu(struct rxrpc_local local,
126	const struct sockaddr_rxrpc *srx)
127	{
128	struct rxrpc_peer *peer;
129	unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
130
131	peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
132	if (peer) {
133	switch (srx->transport.family) {
134	case AF_INET:
135	_net("PEER %d {%d,%u,%pI4+%hu}",
136	peer->debug_id,
137	peer->srx.transport_type,
138	peer->srx.transport.family,
139	&peer->srx.transport.sin.sin_addr,
140	ntohs(peer->srx.transport.sin.sin_port));
141	break;
142	}
143
144	_leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
145	}
146	return peer;
147	}
17926a79	148
224711df DH	149	/*
	150	* assess the MTU size for the network interface through which this peer is
	151	* reached
	152	*/
	153	static void rxrpc_assess_MTU_size(struct rxrpc_peer *peer)
	154	{
	155	struct rtable *rt;
31e4543d	156	struct flowi4 fl4;
224711df DH	157
	158	peer->if_mtu = 1500;
	159
31e4543d	160	rt = ip_route_output_ports(&init_net, &fl4, NULL,
78fbfd8a DM	161	peer->srx.transport.sin.sin_addr.s_addr, 0,
	162	htons(7000), htons(7001),
	163	IPPROTO_UDP, 0, 0);
b23dd4fe DM	164	if (IS_ERR(rt)) {
b23dd4fe DM	165	_leave(" [route err %ld]", PTR_ERR(rt));
224711df DH	166	return;
	167	}
	168
d8d1f30b CG	169	peer->if_mtu = dst_mtu(&rt->dst);
d8d1f30b CG	170	dst_release(&rt->dst);
224711df	171
a6a62b69	172	_leave(" [if_mtu %u]", peer->if_mtu);
224711df DH	173	}
224711df DH	174
17926a79	175	/*
be6e6707	176	* Allocate a peer.
17926a79	177	*/
be6e6707	178	struct rxrpc_peer rxrpc_alloc_peer(struct rxrpc_local local, gfp_t gfp)
17926a79 DH	179	{
	180	struct rxrpc_peer *peer;
	181
	182	_enter("");
	183
	184	peer = kzalloc(sizeof(struct rxrpc_peer), gfp);
	185	if (peer) {
be6e6707 DH	186	atomic_set(&peer->usage, 1);
be6e6707 DH	187	peer->local = local;
f66d7490 DH	188	INIT_HLIST_HEAD(&peer->error_targets);
	189	INIT_WORK(&peer->error_distributor,
	190	&rxrpc_peer_error_distributor);
aa390bbe	191	peer->service_conns = RB_ROOT;
8496af50	192	seqlock_init(&peer->service_conn_lock);
17926a79	193	spin_lock_init(&peer->lock);
17926a79	194	peer->debug_id = atomic_inc_return(&rxrpc_debug_id);
be6e6707 DH	195	}
	196
	197	_leave(" = %p", peer);
	198	return peer;
	199	}
	200
	201	/*
	202	* Set up a new peer.
	203	*/
	204	static struct rxrpc_peer rxrpc_create_peer(struct rxrpc_local local,
	205	struct sockaddr_rxrpc *srx,
	206	unsigned long hash_key,
	207	gfp_t gfp)
	208	{
	209	struct rxrpc_peer *peer;
	210
	211	_enter("");
	212
	213	peer = rxrpc_alloc_peer(local, gfp);
	214	if (peer) {
	215	peer->hash_key = hash_key;
17926a79 DH	216	memcpy(&peer->srx, srx, sizeof(*srx));
17926a79 DH	217
224711df DH	218	rxrpc_assess_MTU_size(peer);
224711df DH	219	peer->mtu = peer->if_mtu;
17926a79 DH	220
	221	if (srx->transport.family == AF_INET) {
	222	peer->hdrsize = sizeof(struct iphdr);
	223	switch (srx->transport_type) {
	224	case SOCK_DGRAM:
	225	peer->hdrsize += sizeof(struct udphdr);
	226	break;
	227	default:
	228	BUG();
	229	break;
	230	}
	231	} else {
	232	BUG();
	233	}
	234
0d12f8a4	235	peer->hdrsize += sizeof(struct rxrpc_wire_header);
17926a79 DH	236	peer->maxdata = peer->mtu - peer->hdrsize;
	237	}
	238
	239	_leave(" = %p", peer);
	240	return peer;
	241	}
	242
	243	/*
	244	* obtain a remote transport endpoint for the specified address
	245	*/
be6e6707 DH	246	struct rxrpc_peer rxrpc_lookup_peer(struct rxrpc_local local,
be6e6707 DH	247	struct sockaddr_rxrpc *srx, gfp_t gfp)
17926a79 DH	248	{
17926a79 DH	249	struct rxrpc_peer peer, candidate;
be6e6707	250	unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
17926a79	251
21454aaa	252	_enter("{%d,%d,%pI4+%hu}",
17926a79 DH	253	srx->transport_type,
17926a79 DH	254	srx->transport_len,
21454aaa	255	&srx->transport.sin.sin_addr,
17926a79 DH	256	ntohs(srx->transport.sin.sin_port));
	257
	258	/* search the peer list first */
be6e6707 DH	259	rcu_read_lock();
	260	peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
	261	if (peer && !rxrpc_get_peer_maybe(peer))
	262	peer = NULL;
	263	rcu_read_unlock();
	264
	265	if (!peer) {
	266	/* The peer is not yet present in hash - create a candidate
	267	* for a new record and then redo the search.
	268	*/
	269	candidate = rxrpc_create_peer(local, srx, hash_key, gfp);
	270	if (!candidate) {
	271	_leave(" = NULL [nomem]");
	272	return NULL;
	273	}
17926a79	274
be6e6707	275	spin_lock(&rxrpc_peer_hash_lock);
17926a79	276
be6e6707 DH	277	/* Need to check that we aren't racing with someone else */
	278	peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
	279	if (peer && !rxrpc_get_peer_maybe(peer))
	280	peer = NULL;
	281	if (!peer)
	282	hash_add_rcu(rxrpc_peer_hash,
	283	&candidate->hash_link, hash_key);
17926a79	284
be6e6707	285	spin_unlock(&rxrpc_peer_hash_lock);
17926a79	286
be6e6707 DH	287	if (peer)
	288	kfree(candidate);
	289	else
	290	peer = candidate;
	291	}
17926a79	292
be6e6707	293	_net("PEER %d {%d,%pI4+%hu}",
17926a79 DH	294	peer->debug_id,
17926a79 DH	295	peer->srx.transport_type,
21454aaa	296	&peer->srx.transport.sin.sin_addr,
17926a79 DH	297	ntohs(peer->srx.transport.sin.sin_port));
17926a79 DH	298
be6e6707	299	_leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
17926a79	300	return peer;
17926a79 DH	301	}
	302
	303	/*
be6e6707	304	* Discard a ref on a remote peer record.
17926a79	305	*/
be6e6707	306	void __rxrpc_put_peer(struct rxrpc_peer *peer)
17926a79	307	{
f66d7490	308	ASSERT(hlist_empty(&peer->error_targets));
17926a79	309
be6e6707 DH	310	spin_lock(&rxrpc_peer_hash_lock);
	311	hash_del_rcu(&peer->hash_link);
	312	spin_unlock(&rxrpc_peer_hash_lock);
17926a79	313
be6e6707	314	kfree_rcu(peer, rcu);
17926a79	315	}