[mirror_ubuntu-bionic-kernel.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;
	}

	/* 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);
		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;
	53	}
	54
	55	/* Step through the peer address in 16-bit portions for speed */
	56	for (i = 0; i < size; i += sizeof(*p), p++)
	57	hash_key += *p;
	58
	59	_leave(" 0x%lx", hash_key);
	60	return hash_key;
	61	}
	62
	63	/*
	64	* Compare a peer to a key. Return -ve, 0 or +ve to indicate less than, same
	65	* or greater than.
	66	*
	67	* Unfortunately, the primitives in linux/hashtable.h don't allow for sorted
	68	* buckets and mid-bucket insertion, so we don't make full use of this
	69	* information at this point.
	70	*/
	71	static long rxrpc_peer_cmp_key(const struct rxrpc_peer *peer,
	72	struct rxrpc_local *local,
	73	const struct sockaddr_rxrpc *srx,
	74	unsigned long hash_key)
	75	{
	76	long diff;
	77
	78	diff = ((peer->hash_key - hash_key) ?:
	79	((unsigned long)peer->local - (unsigned long)local) ?:
	80	(peer->srx.transport_type - srx->transport_type) ?:
	81	(peer->srx.transport_len - srx->transport_len) ?:
	82	(peer->srx.transport.family - srx->transport.family));
	83	if (diff != 0)
	84	return diff;
	85
	86	switch (srx->transport.family) {
	87	case AF_INET:
	88	return ((u16 __force)peer->srx.transport.sin.sin_port -
	89	(u16 __force)srx->transport.sin.sin_port) ?:
	90	memcmp(&peer->srx.transport.sin.sin_addr,
	91	&srx->transport.sin.sin_addr,
	92	sizeof(struct in_addr));
	93	default:
94	BUG();
95	}
96	}
97
98	/*
99	* Look up a remote transport endpoint for the specified address using RCU.
100	*/
101	static struct rxrpc_peer *__rxrpc_lookup_peer_rcu(
102	struct rxrpc_local *local,
103	const struct sockaddr_rxrpc *srx,
104	unsigned long hash_key)
105	{
106	struct rxrpc_peer *peer;
107
108	hash_for_each_possible_rcu(rxrpc_peer_hash, peer, hash_link, hash_key) {
109	if (rxrpc_peer_cmp_key(peer, local, srx, hash_key) == 0) {
110	if (atomic_read(&peer->usage) == 0)
111	return NULL;
112	return peer;
113	}
114	}
115
116	return NULL;
117	}
118
119	/*
120	* Look up a remote transport endpoint for the specified address using RCU.
121	*/
122	struct rxrpc_peer rxrpc_lookup_peer_rcu(struct rxrpc_local local,
123	const struct sockaddr_rxrpc *srx)
124	{
125	struct rxrpc_peer *peer;
126	unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
127
128	peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
129	if (peer) {
130	switch (srx->transport.family) {
131	case AF_INET:
132	_net("PEER %d {%d,%u,%pI4+%hu}",
133	peer->debug_id,
134	peer->srx.transport_type,
135	peer->srx.transport.family,
136	&peer->srx.transport.sin.sin_addr,
137	ntohs(peer->srx.transport.sin.sin_port));
138	break;
139	}
140
141	_leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
142	}
143	return peer;
144	}
17926a79	145
224711df DH	146	/*
	147	* assess the MTU size for the network interface through which this peer is
	148	* reached
	149	*/
	150	static void rxrpc_assess_MTU_size(struct rxrpc_peer *peer)
	151	{
	152	struct rtable *rt;
31e4543d	153	struct flowi4 fl4;
224711df DH	154
	155	peer->if_mtu = 1500;
	156
31e4543d	157	rt = ip_route_output_ports(&init_net, &fl4, NULL,
78fbfd8a DM	158	peer->srx.transport.sin.sin_addr.s_addr, 0,
	159	htons(7000), htons(7001),
	160	IPPROTO_UDP, 0, 0);
b23dd4fe DM	161	if (IS_ERR(rt)) {
b23dd4fe DM	162	_leave(" [route err %ld]", PTR_ERR(rt));
224711df DH	163	return;
	164	}
	165
d8d1f30b CG	166	peer->if_mtu = dst_mtu(&rt->dst);
d8d1f30b CG	167	dst_release(&rt->dst);
224711df	168
a6a62b69	169	_leave(" [if_mtu %u]", peer->if_mtu);
224711df DH	170	}
224711df DH	171
17926a79	172	/*
be6e6707	173	* Allocate a peer.
17926a79	174	*/
be6e6707	175	struct rxrpc_peer rxrpc_alloc_peer(struct rxrpc_local local, gfp_t gfp)
17926a79 DH	176	{
	177	struct rxrpc_peer *peer;
	178
	179	_enter("");
	180
	181	peer = kzalloc(sizeof(struct rxrpc_peer), gfp);
	182	if (peer) {
be6e6707 DH	183	atomic_set(&peer->usage, 1);
be6e6707 DH	184	peer->local = local;
f66d7490 DH	185	INIT_HLIST_HEAD(&peer->error_targets);
	186	INIT_WORK(&peer->error_distributor,
	187	&rxrpc_peer_error_distributor);
17926a79	188	spin_lock_init(&peer->lock);
17926a79	189	peer->debug_id = atomic_inc_return(&rxrpc_debug_id);
be6e6707 DH	190	}
	191
	192	_leave(" = %p", peer);
	193	return peer;
	194	}
	195
	196	/*
	197	* Set up a new peer.
	198	*/
	199	static struct rxrpc_peer rxrpc_create_peer(struct rxrpc_local local,
	200	struct sockaddr_rxrpc *srx,
	201	unsigned long hash_key,
	202	gfp_t gfp)
	203	{
	204	struct rxrpc_peer *peer;
	205
	206	_enter("");
	207
	208	peer = rxrpc_alloc_peer(local, gfp);
	209	if (peer) {
	210	peer->hash_key = hash_key;
17926a79 DH	211	memcpy(&peer->srx, srx, sizeof(*srx));
17926a79 DH	212
224711df DH	213	rxrpc_assess_MTU_size(peer);
224711df DH	214	peer->mtu = peer->if_mtu;
17926a79 DH	215
	216	if (srx->transport.family == AF_INET) {
	217	peer->hdrsize = sizeof(struct iphdr);
	218	switch (srx->transport_type) {
	219	case SOCK_DGRAM:
	220	peer->hdrsize += sizeof(struct udphdr);
	221	break;
	222	default:
	223	BUG();
	224	break;
	225	}
	226	} else {
	227	BUG();
	228	}
	229
0d12f8a4	230	peer->hdrsize += sizeof(struct rxrpc_wire_header);
17926a79 DH	231	peer->maxdata = peer->mtu - peer->hdrsize;
	232	}
	233
	234	_leave(" = %p", peer);
	235	return peer;
	236	}
	237
	238	/*
	239	* obtain a remote transport endpoint for the specified address
	240	*/
be6e6707 DH	241	struct rxrpc_peer rxrpc_lookup_peer(struct rxrpc_local local,
be6e6707 DH	242	struct sockaddr_rxrpc *srx, gfp_t gfp)
17926a79 DH	243	{
17926a79 DH	244	struct rxrpc_peer peer, candidate;
be6e6707	245	unsigned long hash_key = rxrpc_peer_hash_key(local, srx);
17926a79	246
21454aaa	247	_enter("{%d,%d,%pI4+%hu}",
17926a79 DH	248	srx->transport_type,
17926a79 DH	249	srx->transport_len,
21454aaa	250	&srx->transport.sin.sin_addr,
17926a79 DH	251	ntohs(srx->transport.sin.sin_port));
	252
	253	/* search the peer list first */
be6e6707 DH	254	rcu_read_lock();
	255	peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
	256	if (peer && !rxrpc_get_peer_maybe(peer))
	257	peer = NULL;
	258	rcu_read_unlock();
	259
	260	if (!peer) {
	261	/* The peer is not yet present in hash - create a candidate
	262	* for a new record and then redo the search.
	263	*/
	264	candidate = rxrpc_create_peer(local, srx, hash_key, gfp);
	265	if (!candidate) {
	266	_leave(" = NULL [nomem]");
	267	return NULL;
	268	}
17926a79	269
be6e6707	270	spin_lock(&rxrpc_peer_hash_lock);
17926a79	271
be6e6707 DH	272	/* Need to check that we aren't racing with someone else */
	273	peer = __rxrpc_lookup_peer_rcu(local, srx, hash_key);
	274	if (peer && !rxrpc_get_peer_maybe(peer))
	275	peer = NULL;
	276	if (!peer)
	277	hash_add_rcu(rxrpc_peer_hash,
	278	&candidate->hash_link, hash_key);
17926a79	279
be6e6707	280	spin_unlock(&rxrpc_peer_hash_lock);
17926a79	281
be6e6707 DH	282	if (peer)
	283	kfree(candidate);
	284	else
	285	peer = candidate;
	286	}
17926a79	287
be6e6707	288	_net("PEER %d {%d,%pI4+%hu}",
17926a79 DH	289	peer->debug_id,
17926a79 DH	290	peer->srx.transport_type,
21454aaa	291	&peer->srx.transport.sin.sin_addr,
17926a79 DH	292	ntohs(peer->srx.transport.sin.sin_port));
17926a79 DH	293
be6e6707	294	_leave(" = %p {u=%d}", peer, atomic_read(&peer->usage));
17926a79	295	return peer;
17926a79 DH	296	}
	297
	298	/*
be6e6707	299	* Discard a ref on a remote peer record.
17926a79	300	*/
be6e6707	301	void __rxrpc_put_peer(struct rxrpc_peer *peer)
17926a79	302	{
f66d7490	303	ASSERT(hlist_empty(&peer->error_targets));
17926a79	304
be6e6707 DH	305	spin_lock(&rxrpc_peer_hash_lock);
	306	hash_del_rcu(&peer->hash_link);
	307	spin_unlock(&rxrpc_peer_hash_lock);
17926a79	308
be6e6707	309	kfree_rcu(peer, rcu);
17926a79	310	}