[mirror_ubuntu-focal-kernel.git] / net / ipv6 / xfrm6_protocol.c

// SPDX-License-Identifier: GPL-2.0-or-later
/* 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
 */

#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))	\

static 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;
}

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 int 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))
			return 0;

	return -ENOENT;
}

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 int 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))
			return 0;

	return -ENOENT;
}

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 int 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))
			return 0;

	return -ENOENT;
}

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 const struct xfrm_input_afinfo xfrm6_input_afinfo = {
	.family		=	AF_INET6,
	.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
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
7e14ea15 SK	2	/* xfrm6_protocol.c - Generic xfrm protocol multiplexer for ipv6.
	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/xfrm4_protocol.c
7e14ea15 SK	11	*/
	12
	13	#include <linux/init.h>
	14	#include <linux/mutex.h>
	15	#include <linux/skbuff.h>
	16	#include <linux/icmpv6.h>
	17	#include <net/ipv6.h>
	18	#include <net/protocol.h>
	19	#include <net/xfrm.h>
	20
	21	static struct xfrm6_protocol __rcu *esp6_handlers __read_mostly;
	22	static struct xfrm6_protocol __rcu *ah6_handlers __read_mostly;
	23	static struct xfrm6_protocol __rcu *ipcomp6_handlers __read_mostly;
	24	static DEFINE_MUTEX(xfrm6_protocol_mutex);
	25
	26	static inline struct xfrm6_protocol __rcu **proto_handlers(u8 protocol)
	27	{
	28	switch (protocol) {
	29	case IPPROTO_ESP:
	30	return &esp6_handlers;
	31	case IPPROTO_AH:
	32	return &ah6_handlers;
	33	case IPPROTO_COMP:
	34	return &ipcomp6_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 xfrm6_rcv_cb(struct sk_buff *skb, u8 protocol, int err)
7e14ea15 SK	46	{
	47	int ret;
	48	struct xfrm6_protocol *handler;
edb666f0 SK	49	struct xfrm6_protocol __rcu **head = proto_handlers(protocol);
	50
	51	if (!head)
	52	return 0;
7e14ea15 SK	53
	54	for_each_protocol_rcu(*proto_handlers(protocol), handler)
	55	if ((ret = handler->cb_handler(skb, err)) <= 0)
	56	return ret;
	57
	58	return 0;
	59	}
7e14ea15 SK	60
	61	static int xfrm6_esp_rcv(struct sk_buff *skb)
	62	{
	63	int ret;
	64	struct xfrm6_protocol *handler;
	65
	66	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;
	67
	68	for_each_protocol_rcu(esp6_handlers, handler)
	69	if ((ret = handler->handler(skb)) != -EINVAL)
	70	return ret;
	71
	72	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
	73
	74	kfree_skb(skb);
	75	return 0;
	76	}
	77
32bbd879	78	static int xfrm6_esp_err(struct sk_buff skb, struct inet6_skb_parm opt,
7e14ea15 SK	79	u8 type, u8 code, int offset, __be32 info)
	80	{
	81	struct xfrm6_protocol *handler;
	82
	83	for_each_protocol_rcu(esp6_handlers, handler)
	84	if (!handler->err_handler(skb, opt, type, code, offset, info))
32bbd879 SB	85	return 0;
	86
	87	return -ENOENT;
7e14ea15 SK	88	}
	89
	90	static int xfrm6_ah_rcv(struct sk_buff *skb)
	91	{
	92	int ret;
	93	struct xfrm6_protocol *handler;
	94
	95	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;
	96
	97	for_each_protocol_rcu(ah6_handlers, handler)
	98	if ((ret = handler->handler(skb)) != -EINVAL)
	99	return ret;
	100
	101	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
	102
	103	kfree_skb(skb);
	104	return 0;
	105	}
	106
32bbd879	107	static int xfrm6_ah_err(struct sk_buff skb, struct inet6_skb_parm opt,
7e14ea15 SK	108	u8 type, u8 code, int offset, __be32 info)
	109	{
	110	struct xfrm6_protocol *handler;
	111
	112	for_each_protocol_rcu(ah6_handlers, handler)
	113	if (!handler->err_handler(skb, opt, type, code, offset, info))
32bbd879 SB	114	return 0;
	115
	116	return -ENOENT;
7e14ea15 SK	117	}
	118
	119	static int xfrm6_ipcomp_rcv(struct sk_buff *skb)
	120	{
	121	int ret;
	122	struct xfrm6_protocol *handler;
	123
	124	XFRM_TUNNEL_SKB_CB(skb)->tunnel.ip6 = NULL;
	125
	126	for_each_protocol_rcu(ipcomp6_handlers, handler)
	127	if ((ret = handler->handler(skb)) != -EINVAL)
	128	return ret;
	129
	130	icmpv6_send(skb, ICMPV6_DEST_UNREACH, ICMPV6_PORT_UNREACH, 0);
	131
	132	kfree_skb(skb);
	133	return 0;
	134	}
	135
32bbd879	136	static int xfrm6_ipcomp_err(struct sk_buff skb, struct inet6_skb_parm opt,
7e14ea15 SK	137	u8 type, u8 code, int offset, __be32 info)
	138	{
	139	struct xfrm6_protocol *handler;
	140
	141	for_each_protocol_rcu(ipcomp6_handlers, handler)
	142	if (!handler->err_handler(skb, opt, type, code, offset, info))
32bbd879 SB	143	return 0;
	144
	145	return -ENOENT;
7e14ea15 SK	146	}
	147
	148	static const struct inet6_protocol esp6_protocol = {
	149	.handler = xfrm6_esp_rcv,
	150	.err_handler = xfrm6_esp_err,
	151	.flags = INET6_PROTO_NOPOLICY,
	152	};
	153
	154	static const struct inet6_protocol ah6_protocol = {
	155	.handler = xfrm6_ah_rcv,
	156	.err_handler = xfrm6_ah_err,
	157	.flags = INET6_PROTO_NOPOLICY,
	158	};
	159
	160	static const struct inet6_protocol ipcomp6_protocol = {
	161	.handler = xfrm6_ipcomp_rcv,
	162	.err_handler = xfrm6_ipcomp_err,
	163	.flags = INET6_PROTO_NOPOLICY,
	164	};
	165
960fdfde	166	static const struct xfrm_input_afinfo xfrm6_input_afinfo = {
7e14ea15	167	.family = AF_INET6,
7e14ea15 SK	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	}