[deliverable/linux.git] / net / ipv6 / xfrm6_protocol.c

/* xfrm6_protocol.c - Generic xfrm protocol multiplexer for ipv6.
 *
 * Copyright (C) 2013 secunet Security Networks AG
 *
 * Author:
 * Steffen Klassert <steffen.klassert@secunet.com>
 *
 * Based on:
 * net/ipv4/xfrm4_protocol.c
 *
 *	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.
 */

#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/skbuff.h>
#include <linux/icmpv6.h>
#include <net/ipv6.h>
#include <net/protocol.h>
#include <net/xfrm.h>

static struct xfrm6_protocol __rcu *esp6_handlers __read_mostly;
static struct xfrm6_protocol __rcu *ah6_handlers __read_mostly;
static struct xfrm6_protocol __rcu *ipcomp6_handlers __read_mostly;
static DEFINE_MUTEX(xfrm6_protocol_mutex);

static inline struct xfrm6_protocol __rcu **proto_handlers(u8 protocol)
{
	switch (protocol) {
	case IPPROTO_ESP:
		return &esp6_handlers;
	case IPPROTO_AH:
		return &ah6_handlers;
	case IPPROTO_COMP:
		return &ipcomp6_handlers;
	}

	return NULL;
}

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

int xfrm6_rcv_cb(struct sk_buff *skb, u8 protocol, int err)
{
	int ret;
	struct xfrm6_protocol *handler;
	struct xfrm6_protocol __rcu **head = proto_handlers(protocol);

	if (!head)
		return 0;

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

	return 0;
}
EXPORT_SYMBOL(xfrm6_rcv_cb);

static int xfrm6_esp_rcv(struct sk_buff *skb)
{
	int ret;
	struct xfrm6_protocol *handler;

	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;

	for_each_protocol_rcu(esp6_handlers, handler)
		if ((ret = handler->handler(skb)) != -EINVAL)
			return ret;

	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);

	kfree_skb(skb);
	return 0;
}

static void xfrm6_esp_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
			  u8 type, u8 code, int offset, __be32 info)
{
	struct xfrm6_protocol *handler;

	for_each_protocol_rcu(esp6_handlers, handler)
		if (!handler->err_handler(skb, opt, type, code, offset, info))
			break;
}

static int xfrm6_ah_rcv(struct sk_buff *skb)
{
	int ret;
	struct xfrm6_protocol *handler;

	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;

	for_each_protocol_rcu(ah6_handlers, handler)
		if ((ret = handler->handler(skb)) != -EINVAL)
			return ret;

	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);

	kfree_skb(skb);
	return 0;
}

static void xfrm6_ah_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
			 u8 type, u8 code, int offset, __be32 info)
{
	struct xfrm6_protocol *handler;

	for_each_protocol_rcu(ah6_handlers, handler)
		if (!handler->err_handler(skb, opt, type, code, offset, info))
			break;
}

static int xfrm6_ipcomp_rcv(struct sk_buff *skb)
{
	int ret;
	struct xfrm6_protocol *handler;

	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;

	for_each_protocol_rcu(ipcomp6_handlers, handler)
		if ((ret = handler->handler(skb)) != -EINVAL)
			return ret;

	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);

	kfree_skb(skb);
	return 0;
}

static void xfrm6_ipcomp_err(struct sk_buff *skb, struct inet6_skb_parm *opt,
			     u8 type, u8 code, int offset, __be32 info)
{
	struct xfrm6_protocol *handler;

	for_each_protocol_rcu(ipcomp6_handlers, handler)
		if (!handler->err_handler(skb, opt, type, code, offset, info))
			break;
}

static const struct inet6_protocol esp6_protocol = {
	.handler	=	xfrm6_esp_rcv,
	.err_handler	=	xfrm6_esp_err,
	.flags		=	INET6_PROTO_NOPOLICY,
};

static const struct inet6_protocol ah6_protocol = {
	.handler	=	xfrm6_ah_rcv,
	.err_handler	=	xfrm6_ah_err,
	.flags		=	INET6_PROTO_NOPOLICY,
};

static const struct inet6_protocol ipcomp6_protocol = {
	.handler	=	xfrm6_ipcomp_rcv,
	.err_handler	=	xfrm6_ipcomp_err,
	.flags		=	INET6_PROTO_NOPOLICY,
};

static struct xfrm_input_afinfo xfrm6_input_afinfo = {
	.family		=	AF_INET6,
	.owner		=	THIS_MODULE,
	.callback	=	xfrm6_rcv_cb,
};

static inline const struct inet6_protocol *netproto(unsigned char protocol)
{
	switch (protocol) {
	case IPPROTO_ESP:
		return &esp6_protocol;
	case IPPROTO_AH:
		return &ah6_protocol;
	case IPPROTO_COMP:
		return &ipcomp6_protocol;
	}

	return NULL;
}

int xfrm6_protocol_register(struct xfrm6_protocol *handler,
			    unsigned char protocol)
{
	struct xfrm6_protocol __rcu **pprev;
	struct xfrm6_protocol *t;
	bool add_netproto = false;
	int ret = -EEXIST;
	int priority = handler->priority;

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

	mutex_lock(&xfrm6_protocol_mutex);

	if (!rcu_dereference_protected(*proto_handlers(protocol),
				       lockdep_is_held(&xfrm6_protocol_mutex)))
		add_netproto = true;

	for (pprev = proto_handlers(protocol);
	     (t = rcu_dereference_protected(*pprev,
			lockdep_is_held(&xfrm6_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(&xfrm6_protocol_mutex);

	if (add_netproto) {
		if (inet6_add_protocol(netproto(protocol), protocol)) {
			pr_err("%s: can't add protocol\n", __func__);
			ret = -EAGAIN;
		}
	}

	return ret;
}
EXPORT_SYMBOL(xfrm6_protocol_register);

int xfrm6_protocol_deregister(struct xfrm6_protocol *handler,
			      unsigned char protocol)
{
	struct xfrm6_protocol __rcu **pprev;
	struct xfrm6_protocol *t;
	int ret = -ENOENT;

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

	mutex_lock(&xfrm6_protocol_mutex);

	for (pprev = proto_handlers(protocol);
	     (t = rcu_dereference_protected(*pprev,
			lockdep_is_held(&xfrm6_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(&xfrm6_protocol_mutex))) {
		if (inet6_del_protocol(netproto(protocol), protocol) < 0) {
			pr_err("%s: can't remove protocol\n", __func__);
			ret = -EAGAIN;
		}
	}

	mutex_unlock(&xfrm6_protocol_mutex);

	synchronize_net();

	return ret;
}
EXPORT_SYMBOL(xfrm6_protocol_deregister);

int __init xfrm6_protocol_init(void)
{
	return xfrm_input_register_afinfo(&xfrm6_input_afinfo);
}

void xfrm6_protocol_fini(void)
{
	xfrm_input_unregister_afinfo(&xfrm6_input_afinfo);
}
Commit	Line	Data
7e14ea15 SK	1	/* xfrm6_protocol.c - Generic xfrm protocol multiplexer for ipv6.
	2	*
	3	* Copyright (C) 2013 secunet Security Networks AG
	4	*
	5	* Author:
	6	* Steffen Klassert <steffen.klassert@secunet.com>
	7	*
	8	* Based on:
	9	* net/ipv4/xfrm4_protocol.c
	10	*
	11	* This program is free software; you can redistribute it and/or
	12	* modify it under the terms of the GNU General Public License
	13	* as published by the Free Software Foundation; either version
	14	* 2 of the License, or (at your option) any later version.
	15	*/
	16
	17	#include <linux/init.h>
	18	#include <linux/mutex.h>
	19	#include <linux/skbuff.h>
	20	#include <linux/icmpv6.h>
	21	#include <net/ipv6.h>
	22	#include <net/protocol.h>
	23	#include <net/xfrm.h>
	24
	25	static struct xfrm6_protocol __rcu *esp6_handlers __read_mostly;
	26	static struct xfrm6_protocol __rcu *ah6_handlers __read_mostly;
	27	static struct xfrm6_protocol __rcu *ipcomp6_handlers __read_mostly;
	28	static DEFINE_MUTEX(xfrm6_protocol_mutex);
	29
	30	static inline struct xfrm6_protocol __rcu **proto_handlers(u8 protocol)
	31	{
	32	switch (protocol) {
	33	case IPPROTO_ESP:
	34	return &esp6_handlers;
	35	case IPPROTO_AH:
	36	return &ah6_handlers;
	37	case IPPROTO_COMP:
	38	return &ipcomp6_handlers;
	39	}
	40
	41	return NULL;
	42	}
	43
	44	#define for_each_protocol_rcu(head, handler) \
	45	for (handler = rcu_dereference(head); \
	46	handler != NULL; \
	47	handler = rcu_dereference(handler->next)) \
	48
	49	int xfrm6_rcv_cb(struct sk_buff *skb, u8 protocol, int err)
	50	{
	51	int ret;
	52	struct xfrm6_protocol *handler;
edb666f0 SK	53	struct xfrm6_protocol __rcu **head = proto_handlers(protocol);
	54
	55	if (!head)
	56	return 0;
7e14ea15 SK	57
	58	for_each_protocol_rcu(*proto_handlers(protocol), handler)
	59	if ((ret = handler->cb_handler(skb, err)) <= 0)
	60	return ret;
	61
	62	return 0;
	63	}
	64	EXPORT_SYMBOL(xfrm6_rcv_cb);
	65
	66	static int xfrm6_esp_rcv(struct sk_buff *skb)
	67	{
	68	int ret;
	69	struct xfrm6_protocol *handler;
	70
	71	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;
	72
	73	for_each_protocol_rcu(esp6_handlers, handler)
	74	if ((ret = handler->handler(skb)) != -EINVAL)
	75	return ret;
	76
	77	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
	78
	79	kfree_skb(skb);
	80	return 0;
	81	}
	82
	83	static void xfrm6_esp_err(struct sk_buff skb, struct inet6_skb_parm opt,
	84	u8 type, u8 code, int offset, __be32 info)
	85	{
	86	struct xfrm6_protocol *handler;
	87
	88	for_each_protocol_rcu(esp6_handlers, handler)
	89	if (!handler->err_handler(skb, opt, type, code, offset, info))
	90	break;
	91	}
	92
	93	static int xfrm6_ah_rcv(struct sk_buff *skb)
	94	{
	95	int ret;
	96	struct xfrm6_protocol *handler;
	97
	98	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;
	99
	100	for_each_protocol_rcu(ah6_handlers, handler)
	101	if ((ret = handler->handler(skb)) != -EINVAL)
	102	return ret;
	103
	104	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
	105
	106	kfree_skb(skb);
	107	return 0;
	108	}
	109
	110	static void xfrm6_ah_err(struct sk_buff skb, struct inet6_skb_parm opt,
	111	u8 type, u8 code, int offset, __be32 info)
	112	{
	113	struct xfrm6_protocol *handler;
	114
	115	for_each_protocol_rcu(ah6_handlers, handler)
	116	if (!handler->err_handler(skb, opt, type, code, offset, info))
	117	break;
	118	}
	119
	120	static int xfrm6_ipcomp_rcv(struct sk_buff *skb)
121	{
122	int ret;
123	struct xfrm6_protocol *handler;
124
125	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;
126
127	for_each_protocol_rcu(ipcomp6_handlers, handler)
128	if ((ret = handler->handler(skb)) != -EINVAL)
129	return ret;
130
131	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
132
133	kfree_skb(skb);
134	return 0;
135	}
136
137	static void xfrm6_ipcomp_err(struct sk_buff skb, struct inet6_skb_parm opt,
138	u8 type, u8 code, int offset, __be32 info)
139	{
140	struct xfrm6_protocol *handler;
141
142	for_each_protocol_rcu(ipcomp6_handlers, handler)
143	if (!handler->err_handler(skb, opt, type, code, offset, info))
144	break;
145	}
146
147	static const struct inet6_protocol esp6_protocol = {
148	.handler = xfrm6_esp_rcv,
149	.err_handler = xfrm6_esp_err,
150	.flags = INET6_PROTO_NOPOLICY,
151	};
152
153	static const struct inet6_protocol ah6_protocol = {
154	.handler = xfrm6_ah_rcv,
155	.err_handler = xfrm6_ah_err,
156	.flags = INET6_PROTO_NOPOLICY,
157	};
158
159	static const struct inet6_protocol ipcomp6_protocol = {
160	.handler = xfrm6_ipcomp_rcv,
161	.err_handler = xfrm6_ipcomp_err,
162	.flags = INET6_PROTO_NOPOLICY,
163	};
164
165	static struct xfrm_input_afinfo xfrm6_input_afinfo = {
166	.family = AF_INET6,
167	.owner = THIS_MODULE,
168	.callback = xfrm6_rcv_cb,
169	};
170
171	static inline const struct inet6_protocol *netproto(unsigned char protocol)
172	{
173	switch (protocol) {
174	case IPPROTO_ESP:
175	return &esp6_protocol;
176	case IPPROTO_AH:
177	return &ah6_protocol;
178	case IPPROTO_COMP:
179	return &ipcomp6_protocol;
180	}
181
182	return NULL;
183	}
184
185	int xfrm6_protocol_register(struct xfrm6_protocol *handler,
186	unsigned char protocol)
187	{
188	struct xfrm6_protocol __rcu **pprev;
189	struct xfrm6_protocol *t;
190	bool add_netproto = false;
7e14ea15 SK	191	int ret = -EEXIST;
	192	int priority = handler->priority;
	193
edb666f0 SK	194	if (!proto_handlers(protocol) \|\| !netproto(protocol))
	195	return -EINVAL;
	196
7e14ea15 SK	197	mutex_lock(&xfrm6_protocol_mutex);
	198
	199	if (!rcu_dereference_protected(*proto_handlers(protocol),
	200	lockdep_is_held(&xfrm6_protocol_mutex)))
	201	add_netproto = true;
	202
	203	for (pprev = proto_handlers(protocol);
	204	(t = rcu_dereference_protected(*pprev,
	205	lockdep_is_held(&xfrm6_protocol_mutex))) != NULL;
	206	pprev = &t->next) {
	207	if (t->priority < priority)
	208	break;
	209	if (t->priority == priority)
	210	goto err;
	211	}
	212
	213	handler->next = *pprev;
	214	rcu_assign_pointer(*pprev, handler);
	215
	216	ret = 0;
	217
	218	err:
	219	mutex_unlock(&xfrm6_protocol_mutex);
	220
	221	if (add_netproto) {
	222	if (inet6_add_protocol(netproto(protocol), protocol)) {
	223	pr_err("%s: can't add protocol\n", __func__);
	224	ret = -EAGAIN;
	225	}
	226	}
	227
	228	return ret;
	229	}
	230	EXPORT_SYMBOL(xfrm6_protocol_register);
	231
	232	int xfrm6_protocol_deregister(struct xfrm6_protocol *handler,
	233	unsigned char protocol)
	234	{
	235	struct xfrm6_protocol __rcu **pprev;
	236	struct xfrm6_protocol *t;
	237	int ret = -ENOENT;
	238
edb666f0 SK	239	if (!proto_handlers(protocol) \|\| !netproto(protocol))
	240	return -EINVAL;
	241
7e14ea15 SK	242	mutex_lock(&xfrm6_protocol_mutex);
	243
	244	for (pprev = proto_handlers(protocol);
	245	(t = rcu_dereference_protected(*pprev,
	246	lockdep_is_held(&xfrm6_protocol_mutex))) != NULL;
	247	pprev = &t->next) {
	248	if (t == handler) {
	249	*pprev = handler->next;
	250	ret = 0;
	251	break;
	252	}
	253	}
	254
	255	if (!rcu_dereference_protected(*proto_handlers(protocol),
	256	lockdep_is_held(&xfrm6_protocol_mutex))) {
	257	if (inet6_del_protocol(netproto(protocol), protocol) < 0) {
	258	pr_err("%s: can't remove protocol\n", __func__);
	259	ret = -EAGAIN;
	260	}
	261	}
	262
	263	mutex_unlock(&xfrm6_protocol_mutex);
	264
	265	synchronize_net();
	266
	267	return ret;
	268	}
	269	EXPORT_SYMBOL(xfrm6_protocol_deregister);
	270
	271	int __init xfrm6_protocol_init(void)
	272	{
	273	return xfrm_input_register_afinfo(&xfrm6_input_afinfo);
	274	}
	275
	276	void xfrm6_protocol_fini(void)
	277	{
	278	xfrm_input_unregister_afinfo(&xfrm6_input_afinfo);
	279	}