[linux-2.6-block.git] / net / ipv4 / xfrm4_protocol.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* xfrm4_protocol.c - Generic xfrm protocol multiplexer.
 *
 * Copyright (C) 2013 secunet Security Networks AG
 *
 * Author:
 * Steffen Klassert <steffen.klassert@secunet.com>
 *
 * Based on:
 * net/ipv4/tunnel4.c
 */

#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/skbuff.h>
#include <net/icmp.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <net/xfrm.h>

static struct xfrm4_protocol __rcu *esp4_handlers __read_mostly;
static struct xfrm4_protocol __rcu *ah4_handlers __read_mostly;
static struct xfrm4_protocol __rcu *ipcomp4_handlers __read_mostly;
static DEFINE_MUTEX(xfrm4_protocol_mutex);

static inline struct xfrm4_protocol __rcu **proto_handlers(u8 protocol)
{
	switch (protocol) {
	case IPPROTO_ESP:
		return &esp4_handlers;
	case IPPROTO_AH:
		return &ah4_handlers;
	case IPPROTO_COMP:
		return &ipcomp4_handlers;
	}

	return NULL;
}

#define for_each_protocol_rcu(head, handler)		\
	for (handler = rcu_dereference(head);		\
	     handler != NULL;				\
	     handler = rcu_dereference(handler->next))	\

static int xfrm4_rcv_cb(struct sk_buff *skb, u8 protocol, int err)
{
	int ret;
	struct xfrm4_protocol *handler;
	struct xfrm4_protocol __rcu **head = proto_handlers(protocol);

	if (!head)
		return 0;

	for_each_protocol_rcu(*head, handler)
		if ((ret = handler->cb_handler(skb, err)) <= 0)
			return ret;

	return 0;
}

int xfrm4_rcv_encap(struct sk_buff *skb, int nexthdr, __be32 spi,
		    int encap_type)
{
	int ret;
	struct xfrm4_protocol *handler;
	struct xfrm4_protocol __rcu **head = proto_handlers(nexthdr);

	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
	XFRM_SPI_SKB_CB(skb)->family = AF_INET;
	XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);

	if (!head)
		goto out;

	for_each_protocol_rcu(*head, handler)
		if ((ret = handler->input_handler(skb, nexthdr, spi, encap_type)) != -EINVAL)
			return ret;

out:
	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);

	kfree_skb(skb);
	return 0;
}
EXPORT_SYMBOL(xfrm4_rcv_encap);

static int xfrm4_esp_rcv(struct sk_buff *skb)
{
	int ret;
	struct xfrm4_protocol *handler;

	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;

	for_each_protocol_rcu(esp4_handlers, handler)
		if ((ret = handler->handler(skb)) != -EINVAL)
			return ret;

	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);

	kfree_skb(skb);
	return 0;
}

static int xfrm4_esp_err(struct sk_buff *skb, u32 info)
{
	struct xfrm4_protocol *handler;

	for_each_protocol_rcu(esp4_handlers, handler)
		if (!handler->err_handler(skb, info))
			return 0;

	return -ENOENT;
}

static int xfrm4_ah_rcv(struct sk_buff *skb)
{
	int ret;
	struct xfrm4_protocol *handler;

	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;

	for_each_protocol_rcu(ah4_handlers, handler)
		if ((ret = handler->handler(skb)) != -EINVAL)
			return ret;

	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);

	kfree_skb(skb);
	return 0;
}

static int xfrm4_ah_err(struct sk_buff *skb, u32 info)
{
	struct xfrm4_protocol *handler;

	for_each_protocol_rcu(ah4_handlers, handler)
		if (!handler->err_handler(skb, info))
			return 0;

	return -ENOENT;
}

static int xfrm4_ipcomp_rcv(struct sk_buff *skb)
{
	int ret;
	struct xfrm4_protocol *handler;

	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;

	for_each_protocol_rcu(ipcomp4_handlers, handler)
		if ((ret = handler->handler(skb)) != -EINVAL)
			return ret;

	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);

	kfree_skb(skb);
	return 0;
}

static int xfrm4_ipcomp_err(struct sk_buff *skb, u32 info)
{
	struct xfrm4_protocol *handler;

	for_each_protocol_rcu(ipcomp4_handlers, handler)
		if (!handler->err_handler(skb, info))
			return 0;

	return -ENOENT;
}

static const struct net_protocol esp4_protocol = {
	.handler	=	xfrm4_esp_rcv,
	.err_handler	=	xfrm4_esp_err,
	.no_policy	=	1,
	.netns_ok	=	1,
};

static const struct net_protocol ah4_protocol = {
	.handler	=	xfrm4_ah_rcv,
	.err_handler	=	xfrm4_ah_err,
	.no_policy	=	1,
	.netns_ok	=	1,
};

static const struct net_protocol ipcomp4_protocol = {
	.handler	=	xfrm4_ipcomp_rcv,
	.err_handler	=	xfrm4_ipcomp_err,
	.no_policy	=	1,
	.netns_ok	=	1,
};

static const struct xfrm_input_afinfo xfrm4_input_afinfo = {
	.family		=	AF_INET,
	.callback	=	xfrm4_rcv_cb,
};

static inline const struct net_protocol *netproto(unsigned char protocol)
{
	switch (protocol) {
	case IPPROTO_ESP:
		return &esp4_protocol;
	case IPPROTO_AH:
		return &ah4_protocol;
	case IPPROTO_COMP:
		return &ipcomp4_protocol;
	}

	return NULL;
}

int xfrm4_protocol_register(struct xfrm4_protocol *handler,
			    unsigned char protocol)
{
	struct xfrm4_protocol __rcu **pprev;
	struct xfrm4_protocol *t;
	bool add_netproto = false;
	int ret = -EEXIST;
	int priority = handler->priority;

	if (!proto_handlers(protocol) || !netproto(protocol))
		return -EINVAL;

	mutex_lock(&xfrm4_protocol_mutex);

	if (!rcu_dereference_protected(*proto_handlers(protocol),
				       lockdep_is_held(&xfrm4_protocol_mutex)))
		add_netproto = true;

	for (pprev = proto_handlers(protocol);
	     (t = rcu_dereference_protected(*pprev,
			lockdep_is_held(&xfrm4_protocol_mutex))) != NULL;
	     pprev = &t->next) {
		if (t->priority < priority)
			break;
		if (t->priority == priority)
			goto err;
	}

	handler->next = *pprev;
	rcu_assign_pointer(*pprev, handler);

	ret = 0;

err:
	mutex_unlock(&xfrm4_protocol_mutex);

	if (add_netproto) {
		if (inet_add_protocol(netproto(protocol), protocol)) {
			pr_err("%s: can't add protocol\n", __func__);
			ret = -EAGAIN;
		}
	}

	return ret;
}
EXPORT_SYMBOL(xfrm4_protocol_register);

int xfrm4_protocol_deregister(struct xfrm4_protocol *handler,
			      unsigned char protocol)
{
	struct xfrm4_protocol __rcu **pprev;
	struct xfrm4_protocol *t;
	int ret = -ENOENT;

	if (!proto_handlers(protocol) || !netproto(protocol))
		return -EINVAL;

	mutex_lock(&xfrm4_protocol_mutex);

	for (pprev = proto_handlers(protocol);
	     (t = rcu_dereference_protected(*pprev,
			lockdep_is_held(&xfrm4_protocol_mutex))) != NULL;
	     pprev = &t->next) {
		if (t == handler) {
			*pprev = handler->next;
			ret = 0;
			break;
		}
	}

	if (!rcu_dereference_protected(*proto_handlers(protocol),
				       lockdep_is_held(&xfrm4_protocol_mutex))) {
		if (inet_del_protocol(netproto(protocol), protocol) < 0) {
			pr_err("%s: can't remove protocol\n", __func__);
			ret = -EAGAIN;
		}
	}

	mutex_unlock(&xfrm4_protocol_mutex);

	synchronize_net();

	return ret;
}
EXPORT_SYMBOL(xfrm4_protocol_deregister);

void __init xfrm4_protocol_init(void)
{
	xfrm_input_register_afinfo(&xfrm4_input_afinfo);
}
EXPORT_SYMBOL(xfrm4_protocol_init);
Commit	Line	Data
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
3328715e SK	2	/* xfrm4_protocol.c - Generic xfrm protocol multiplexer.
	3	*
	4	* Copyright (C) 2013 secunet Security Networks AG
	5	*
	6	* Author:
	7	* Steffen Klassert <steffen.klassert@secunet.com>
	8	*
	9	* Based on:
	10	* net/ipv4/tunnel4.c
3328715e SK	11	*/
	12
	13	#include <linux/init.h>
	14	#include <linux/mutex.h>
	15	#include <linux/skbuff.h>
	16	#include <net/icmp.h>
	17	#include <net/ip.h>
	18	#include <net/protocol.h>
	19	#include <net/xfrm.h>
	20
	21	static struct xfrm4_protocol __rcu *esp4_handlers __read_mostly;
	22	static struct xfrm4_protocol __rcu *ah4_handlers __read_mostly;
	23	static struct xfrm4_protocol __rcu *ipcomp4_handlers __read_mostly;
	24	static DEFINE_MUTEX(xfrm4_protocol_mutex);
	25
	26	static inline struct xfrm4_protocol __rcu **proto_handlers(u8 protocol)
	27	{
	28	switch (protocol) {
	29	case IPPROTO_ESP:
	30	return &esp4_handlers;
	31	case IPPROTO_AH:
	32	return &ah4_handlers;
	33	case IPPROTO_COMP:
	34	return &ipcomp4_handlers;
	35	}
	36
	37	return NULL;
	38	}
	39
	40	#define for_each_protocol_rcu(head, handler) \
	41	for (handler = rcu_dereference(head); \
	42	handler != NULL; \
	43	handler = rcu_dereference(handler->next)) \
	44
bb9cd077	45	static int xfrm4_rcv_cb(struct sk_buff *skb, u8 protocol, int err)
3328715e SK	46	{
	47	int ret;
	48	struct xfrm4_protocol *handler;
61622cc6	49	struct xfrm4_protocol __rcu **head = proto_handlers(protocol);
3328715e	50
61622cc6 SK	51	if (!head)
	52	return 0;
	53
	54	for_each_protocol_rcu(*head, handler)
3328715e SK	55	if ((ret = handler->cb_handler(skb, err)) <= 0)
	56	return ret;
	57
	58	return 0;
	59	}
3328715e SK	60
	61	int xfrm4_rcv_encap(struct sk_buff *skb, int nexthdr, __be32 spi,
	62	int encap_type)
	63	{
	64	int ret;
	65	struct xfrm4_protocol *handler;
61622cc6	66	struct xfrm4_protocol __rcu **head = proto_handlers(nexthdr);
3328715e	67
70be6c91	68	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
3328715e SK	69	XFRM_SPI_SKB_CB(skb)->family = AF_INET;
	70	XFRM_SPI_SKB_CB(skb)->daddroff = offsetof(struct iphdr, daddr);
	71
61622cc6 SK	72	if (!head)
	73	goto out;
	74
	75	for_each_protocol_rcu(*head, handler)
3328715e SK	76	if ((ret = handler->input_handler(skb, nexthdr, spi, encap_type)) != -EINVAL)
	77	return ret;
	78
61622cc6	79	out:
3328715e SK	80	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
	81
	82	kfree_skb(skb);
	83	return 0;
	84	}
	85	EXPORT_SYMBOL(xfrm4_rcv_encap);
	86
	87	static int xfrm4_esp_rcv(struct sk_buff *skb)
	88	{
	89	int ret;
	90	struct xfrm4_protocol *handler;
	91
70be6c91 SK	92	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
70be6c91 SK	93
3328715e SK	94	for_each_protocol_rcu(esp4_handlers, handler)
	95	if ((ret = handler->handler(skb)) != -EINVAL)
	96	return ret;
	97
	98	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
	99
	100	kfree_skb(skb);
	101	return 0;
	102	}
	103
32bbd879	104	static int xfrm4_esp_err(struct sk_buff *skb, u32 info)
3328715e SK	105	{
	106	struct xfrm4_protocol *handler;
	107
	108	for_each_protocol_rcu(esp4_handlers, handler)
	109	if (!handler->err_handler(skb, info))
32bbd879 SB	110	return 0;
	111
	112	return -ENOENT;
3328715e SK	113	}
	114
	115	static int xfrm4_ah_rcv(struct sk_buff *skb)
	116	{
	117	int ret;
	118	struct xfrm4_protocol *handler;
	119
70be6c91 SK	120	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
70be6c91 SK	121
3328715e SK	122	for_each_protocol_rcu(ah4_handlers, handler)
3328715e SK	123	if ((ret = handler->handler(skb)) != -EINVAL)
1759389e	124	return ret;
3328715e SK	125
	126	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
	127
	128	kfree_skb(skb);
	129	return 0;
	130	}
	131
32bbd879	132	static int xfrm4_ah_err(struct sk_buff *skb, u32 info)
3328715e SK	133	{
	134	struct xfrm4_protocol *handler;
	135
	136	for_each_protocol_rcu(ah4_handlers, handler)
	137	if (!handler->err_handler(skb, info))
32bbd879 SB	138	return 0;
	139
	140	return -ENOENT;
3328715e SK	141	}
	142
	143	static int xfrm4_ipcomp_rcv(struct sk_buff *skb)
	144	{
	145	int ret;
	146	struct xfrm4_protocol *handler;
	147
70be6c91 SK	148	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip4 = NULL;
70be6c91 SK	149
3328715e SK	150	for_each_protocol_rcu(ipcomp4_handlers, handler)
	151	if ((ret = handler->handler(skb)) != -EINVAL)
	152	return ret;
	153
	154	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_PORT_UNREACH, 0);
	155
	156	kfree_skb(skb);
	157	return 0;
	158	}
	159
32bbd879	160	static int xfrm4_ipcomp_err(struct sk_buff *skb, u32 info)
3328715e SK	161	{
	162	struct xfrm4_protocol *handler;
	163
	164	for_each_protocol_rcu(ipcomp4_handlers, handler)
	165	if (!handler->err_handler(skb, info))
32bbd879 SB	166	return 0;
	167
	168	return -ENOENT;
3328715e SK	169	}
	170
	171	static const struct net_protocol esp4_protocol = {
	172	.handler = xfrm4_esp_rcv,
	173	.err_handler = xfrm4_esp_err,
	174	.no_policy = 1,
	175	.netns_ok = 1,
	176	};
	177
	178	static const struct net_protocol ah4_protocol = {
	179	.handler = xfrm4_ah_rcv,
	180	.err_handler = xfrm4_ah_err,
	181	.no_policy = 1,
	182	.netns_ok = 1,
	183	};
	184
	185	static const struct net_protocol ipcomp4_protocol = {
	186	.handler = xfrm4_ipcomp_rcv,
	187	.err_handler = xfrm4_ipcomp_err,
	188	.no_policy = 1,
	189	.netns_ok = 1,
	190	};
	191
960fdfde	192	static const struct xfrm_input_afinfo xfrm4_input_afinfo = {
2f32b51b	193	.family = AF_INET,
2f32b51b SK	194	.callback = xfrm4_rcv_cb,
	195	};
	196
3328715e SK	197	static inline const struct net_protocol *netproto(unsigned char protocol)
	198	{
	199	switch (protocol) {
	200	case IPPROTO_ESP:
	201	return &esp4_protocol;
	202	case IPPROTO_AH:
	203	return &ah4_protocol;
	204	case IPPROTO_COMP:
	205	return &ipcomp4_protocol;
	206	}
	207
	208	return NULL;
	209	}
	210
	211	int xfrm4_protocol_register(struct xfrm4_protocol *handler,
	212	unsigned char protocol)
	213	{
	214	struct xfrm4_protocol __rcu **pprev;
	215	struct xfrm4_protocol *t;
	216	bool add_netproto = false;
3328715e SK	217	int ret = -EEXIST;
	218	int priority = handler->priority;
	219
61622cc6 SK	220	if (!proto_handlers(protocol) \|\| !netproto(protocol))
	221	return -EINVAL;
	222
3328715e SK	223	mutex_lock(&xfrm4_protocol_mutex);
	224
	225	if (!rcu_dereference_protected(*proto_handlers(protocol),
	226	lockdep_is_held(&xfrm4_protocol_mutex)))
	227	add_netproto = true;
	228
	229	for (pprev = proto_handlers(protocol);
	230	(t = rcu_dereference_protected(*pprev,
	231	lockdep_is_held(&xfrm4_protocol_mutex))) != NULL;
	232	pprev = &t->next) {
	233	if (t->priority < priority)
	234	break;
	235	if (t->priority == priority)
	236	goto err;
	237	}
	238
	239	handler->next = *pprev;
	240	rcu_assign_pointer(*pprev, handler);
	241
	242	ret = 0;
	243
	244	err:
	245	mutex_unlock(&xfrm4_protocol_mutex);
	246
	247	if (add_netproto) {
	248	if (inet_add_protocol(netproto(protocol), protocol)) {
	249	pr_err("%s: can't add protocol\n", __func__);
	250	ret = -EAGAIN;
	251	}
	252	}
	253
	254	return ret;
	255	}
	256	EXPORT_SYMBOL(xfrm4_protocol_register);
	257
	258	int xfrm4_protocol_deregister(struct xfrm4_protocol *handler,
	259	unsigned char protocol)
	260	{
	261	struct xfrm4_protocol __rcu **pprev;
	262	struct xfrm4_protocol *t;
	263	int ret = -ENOENT;
	264
61622cc6 SK	265	if (!proto_handlers(protocol) \|\| !netproto(protocol))
	266	return -EINVAL;
	267
3328715e SK	268	mutex_lock(&xfrm4_protocol_mutex);
	269
	270	for (pprev = proto_handlers(protocol);
	271	(t = rcu_dereference_protected(*pprev,
	272	lockdep_is_held(&xfrm4_protocol_mutex))) != NULL;
	273	pprev = &t->next) {
	274	if (t == handler) {
	275	*pprev = handler->next;
	276	ret = 0;
	277	break;
	278	}
	279	}
	280
	281	if (!rcu_dereference_protected(*proto_handlers(protocol),
	282	lockdep_is_held(&xfrm4_protocol_mutex))) {
	283	if (inet_del_protocol(netproto(protocol), protocol) < 0) {
	284	pr_err("%s: can't remove protocol\n", __func__);
	285	ret = -EAGAIN;
	286	}
	287	}
	288
	289	mutex_unlock(&xfrm4_protocol_mutex);
	290
	291	synchronize_net();
	292
	293	return ret;
	294	}
	295	EXPORT_SYMBOL(xfrm4_protocol_deregister);
2f32b51b SK	296
	297	void __init xfrm4_protocol_init(void)
	298	{
	299	xfrm_input_register_afinfo(&xfrm4_input_afinfo);
	300	}
	301	EXPORT_SYMBOL(xfrm4_protocol_init);