[linux.git] / net / ipv6 / xfrm6_output.c

/*
 * xfrm6_output.c - Common IPsec encapsulation code for IPv6.
 * Copyright (C) 2002 USAGI/WIDE Project
 * Copyright (c) 2004 Herbert Xu <[email protected]>
 *
 * 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/if_ether.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/icmpv6.h>
#include <linux/netfilter_ipv6.h>
#include <net/dst.h>
#include <net/ipv6.h>
#include <net/ip6_route.h>
#include <net/xfrm.h>

int xfrm6_find_1stfragopt(struct xfrm_state *x, struct sk_buff *skb,
			  u8 **prevhdr)
{
	return ip6_find_1stfragopt(skb, prevhdr);
}
EXPORT_SYMBOL(xfrm6_find_1stfragopt);

static int xfrm6_local_dontfrag(struct sk_buff *skb)
{
	int proto;
	struct sock *sk = skb->sk;

	if (sk) {
		if (sk->sk_family != AF_INET6)
			return 0;

		proto = sk->sk_protocol;
		if (proto == IPPROTO_UDP || proto == IPPROTO_RAW)
			return inet6_sk(sk)->dontfrag;
	}

	return 0;
}

static void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu)
{
	struct flowi6 fl6;
	struct sock *sk = skb->sk;

	fl6.flowi6_oif = sk->sk_bound_dev_if;
	fl6.daddr = ipv6_hdr(skb)->daddr;

	ipv6_local_rxpmtu(sk, &fl6, mtu);
}

void xfrm6_local_error(struct sk_buff *skb, u32 mtu)
{
	struct flowi6 fl6;
	const struct ipv6hdr *hdr;
	struct sock *sk = skb->sk;

	hdr = skb->encapsulation ? inner_ipv6_hdr(skb) : ipv6_hdr(skb);
	fl6.fl6_dport = inet_sk(sk)->inet_dport;
	fl6.daddr = hdr->daddr;

	ipv6_local_error(sk, EMSGSIZE, &fl6, mtu);
}

static int xfrm6_tunnel_check_size(struct sk_buff *skb)
{
	int mtu, ret = 0;
	struct dst_entry *dst = skb_dst(skb);

	mtu = dst_mtu(dst);
	if (mtu < IPV6_MIN_MTU)
		mtu = IPV6_MIN_MTU;

	if (!skb->ignore_df && skb->len > mtu) {
		skb->dev = dst->dev;
		skb->protocol = htons(ETH_P_IPV6);

		if (xfrm6_local_dontfrag(skb))
			xfrm6_local_rxpmtu(skb, mtu);
		else if (skb->sk)
			xfrm_local_error(skb, mtu);
		else
			icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
		ret = -EMSGSIZE;
	}

	return ret;
}

int xfrm6_extract_output(struct xfrm_state *x, struct sk_buff *skb)
{
	int err;

	err = xfrm6_tunnel_check_size(skb);
	if (err)
		return err;

	XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr;

	return xfrm6_extract_header(skb);
}

int xfrm6_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
{
	int err;

	err = xfrm_inner_extract_output(x, skb);
	if (err)
		return err;

	skb->ignore_df = 1;
	skb->protocol = htons(ETH_P_IPV6);

	return x->outer_mode->output2(x, skb);
}
EXPORT_SYMBOL(xfrm6_prepare_output);

int xfrm6_output_finish(struct sock *sk, struct sk_buff *skb)
{
	memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));

#ifdef CONFIG_NETFILTER
	IP6CB(skb)->flags |= IP6SKB_XFRM_TRANSFORMED;
#endif

	return xfrm_output(sk, skb);
}

static int __xfrm6_output_finish(struct net *net, struct sock *sk, struct sk_buff *skb)
{
	struct xfrm_state *x = skb_dst(skb)->xfrm;

	return x->outer_mode->afinfo->output_finish(sk, skb);
}

static int __xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
{
	struct dst_entry *dst = skb_dst(skb);
	struct xfrm_state *x = dst->xfrm;
	int mtu;
	bool toobig;

#ifdef CONFIG_NETFILTER
	if (!x) {
		IP6CB(skb)->flags |= IP6SKB_REROUTED;
		return dst_output(net, sk, skb);
	}
#endif

	if (x->props.mode != XFRM_MODE_TUNNEL)
		goto skip_frag;

	if (skb->protocol == htons(ETH_P_IPV6))
		mtu = ip6_skb_dst_mtu(skb);
	else
		mtu = dst_mtu(skb_dst(skb));

	toobig = skb->len > mtu && !skb_is_gso(skb);

	if (toobig && xfrm6_local_dontfrag(skb)) {
		xfrm6_local_rxpmtu(skb, mtu);
		return -EMSGSIZE;
	} else if (!skb->ignore_df && toobig && skb->sk) {
		xfrm_local_error(skb, mtu);
		return -EMSGSIZE;
	}

	if (toobig || dst_allfrag(skb_dst(skb)))
		return ip6_fragment(net, sk, skb,
				    __xfrm6_output_finish);

skip_frag:
	return x->outer_mode->afinfo->output_finish(sk, skb);
}

int xfrm6_output(struct net *net, struct sock *sk, struct sk_buff *skb)
{
	return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
			    net, sk, skb,  NULL, skb_dst(skb)->dev,
			    __xfrm6_output,
			    !(IP6CB(skb)->flags & IP6SKB_REROUTED));
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* xfrm6_output.c - Common IPsec encapsulation code for IPv6.
	3	* Copyright (C) 2002 USAGI/WIDE Project
	4	* Copyright (c) 2004 Herbert Xu <[email protected]>
1ab1457c	5	*
1da177e4 LT	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
406ef77c	12	#include <linux/if_ether.h>
36cf9acf HX	13	#include <linux/kernel.h>
36cf9acf HX	14	#include <linux/module.h>
1da177e4	15	#include <linux/skbuff.h>
1da177e4	16	#include <linux/icmpv6.h>
16a6677f	17	#include <linux/netfilter_ipv6.h>
36cf9acf	18	#include <net/dst.h>
1da177e4	19	#include <net/ipv6.h>
ad0081e4	20	#include <net/ip6_route.h>
1da177e4 LT	21	#include <net/xfrm.h>
1da177e4 LT	22
aee5adb4 MN	23	int xfrm6_find_1stfragopt(struct xfrm_state x, struct sk_buff skb,
	24	u8 **prevhdr)
	25	{
	26	return ip6_find_1stfragopt(skb, prevhdr);
	27	}
7159039a YH	28	EXPORT_SYMBOL(xfrm6_find_1stfragopt);
7159039a YH	29
dd767856 SK	30	static int xfrm6_local_dontfrag(struct sk_buff *skb)
	31	{
	32	int proto;
	33	struct sock *sk = skb->sk;
	34
	35	if (sk) {
628e341f HFS	36	if (sk->sk_family != AF_INET6)
628e341f HFS	37	return 0;
dd767856	38
628e341f	39	proto = sk->sk_protocol;
dd767856 SK	40	if (proto == IPPROTO_UDP \|\| proto == IPPROTO_RAW)
	41	return inet6_sk(sk)->dontfrag;
	42	}
	43
	44	return 0;
	45	}
	46
	47	static void xfrm6_local_rxpmtu(struct sk_buff *skb, u32 mtu)
	48	{
	49	struct flowi6 fl6;
	50	struct sock *sk = skb->sk;
	51
	52	fl6.flowi6_oif = sk->sk_bound_dev_if;
4e3fd7a0	53	fl6.daddr = ipv6_hdr(skb)->daddr;
dd767856 SK	54
	55	ipv6_local_rxpmtu(sk, &fl6, mtu);
	56	}
	57
628e341f	58	void xfrm6_local_error(struct sk_buff *skb, u32 mtu)
dd767856 SK	59	{
dd767856 SK	60	struct flowi6 fl6;
5d0ff542	61	const struct ipv6hdr *hdr;
dd767856 SK	62	struct sock *sk = skb->sk;
dd767856 SK	63
5d0ff542	64	hdr = skb->encapsulation ? inner_ipv6_hdr(skb) : ipv6_hdr(skb);
dd767856	65	fl6.fl6_dport = inet_sk(sk)->inet_dport;
5d0ff542	66	fl6.daddr = hdr->daddr;
dd767856 SK	67
	68	ipv6_local_error(sk, EMSGSIZE, &fl6, mtu);
	69	}
	70
1da177e4 LT	71	static int xfrm6_tunnel_check_size(struct sk_buff *skb)
	72	{
	73	int mtu, ret = 0;
adf30907	74	struct dst_entry *dst = skb_dst(skb);
1da177e4 LT	75
	76	mtu = dst_mtu(dst);
	77	if (mtu < IPV6_MIN_MTU)
	78	mtu = IPV6_MIN_MTU;
	79
60ff7467	80	if (!skb->ignore_df && skb->len > mtu) {
180e4250	81	skb->dev = dst->dev;
ca064bd8	82	skb->protocol = htons(ETH_P_IPV6);
dd767856 SK	83
	84	if (xfrm6_local_dontfrag(skb))
	85	xfrm6_local_rxpmtu(skb, mtu);
	86	else if (skb->sk)
628e341f	87	xfrm_local_error(skb, mtu);
dd767856 SK	88	else
dd767856 SK	89	icmpv6_send(skb, ICMPV6_PKT_TOOBIG, 0, mtu);
1da177e4 LT	90	ret = -EMSGSIZE;
	91	}
	92
	93	return ret;
	94	}
	95
36cf9acf HX	96	int xfrm6_extract_output(struct xfrm_state x, struct sk_buff skb)
	97	{
	98	int err;
	99
	100	err = xfrm6_tunnel_check_size(skb);
	101	if (err)
	102	return err;
	103
60d5fcfb HX	104	XFRM_MODE_SKB_CB(skb)->protocol = ipv6_hdr(skb)->nexthdr;
60d5fcfb HX	105
36cf9acf HX	106	return xfrm6_extract_header(skb);
	107	}
	108
	109	int xfrm6_prepare_output(struct xfrm_state x, struct sk_buff skb)
	110	{
	111	int err;
	112
df9dcb45	113	err = xfrm_inner_extract_output(x, skb);
36cf9acf HX	114	if (err)
	115	return err;
	116
60ff7467	117	skb->ignore_df = 1;
044a832a	118	skb->protocol = htons(ETH_P_IPV6);
36cf9acf HX	119
	120	return x->outer_mode->output2(x, skb);
	121	}
	122	EXPORT_SYMBOL(xfrm6_prepare_output);
	123
7026b1dd	124	int xfrm6_output_finish(struct sock sk, struct sk_buff skb)
09b8f7a9	125	{
5596732f	126	memset(IP6CB(skb), 0, sizeof(*IP6CB(skb)));
5596732f	127
862b82c6 HX	128	#ifdef CONFIG_NETFILTER
	129	IP6CB(skb)->flags \|= IP6SKB_XFRM_TRANSFORMED;
	130	#endif
09b8f7a9	131
7026b1dd	132	return xfrm_output(sk, skb);
09b8f7a9 HX	133	}
09b8f7a9 HX	134
7d8c6e39 EB	135	static int __xfrm6_output_finish(struct net net, struct sock sk, struct sk_buff *skb)
	136	{
	137	struct xfrm_state *x = skb_dst(skb)->xfrm;
b1842ffd	138
7d8c6e39 EB	139	return x->outer_mode->afinfo->output_finish(sk, skb);
	140	}
	141
0c4b51f0	142	static int __xfrm6_output(struct net net, struct sock sk, struct sk_buff *skb)
ad0081e4 DS	143	{
	144	struct dst_entry *dst = skb_dst(skb);
	145	struct xfrm_state *x = dst->xfrm;
5a25cf1e	146	int mtu;
93efac3f	147	bool toobig;
0ea9d5e3	148
5596732f SK	149	#ifdef CONFIG_NETFILTER
	150	if (!x) {
	151	IP6CB(skb)->flags \|= IP6SKB_REROUTED;
13206b6b	152	return dst_output(net, sk, skb);
5596732f SK	153	}
	154	#endif
	155
93efac3f HX	156	if (x->props.mode != XFRM_MODE_TUNNEL)
	157	goto skip_frag;
	158
5a25cf1e HFS	159	if (skb->protocol == htons(ETH_P_IPV6))
	160	mtu = ip6_skb_dst_mtu(skb);
	161	else
	162	mtu = dst_mtu(skb_dst(skb));
dd767856	163
93efac3f HX	164	toobig = skb->len > mtu && !skb_is_gso(skb);
	165
	166	if (toobig && xfrm6_local_dontfrag(skb)) {
dd767856 SK	167	xfrm6_local_rxpmtu(skb, mtu);
dd767856 SK	168	return -EMSGSIZE;
93efac3f	169	} else if (!skb->ignore_df && toobig && skb->sk) {
628e341f	170	xfrm_local_error(skb, mtu);
dd767856 SK	171	return -EMSGSIZE;
dd767856 SK	172	}
ad0081e4	173
93efac3f	174	if (toobig \|\| dst_allfrag(skb_dst(skb)))
7d8c6e39 EB	175	return ip6_fragment(net, sk, skb,
7d8c6e39 EB	176	__xfrm6_output_finish);
93efac3f HX	177
93efac3f HX	178	skip_frag:
7026b1dd	179	return x->outer_mode->afinfo->output_finish(sk, skb);
ad0081e4 DS	180	}
ad0081e4 DS	181
ede2059d	182	int xfrm6_output(struct net net, struct sock sk, struct sk_buff *skb)
16a6677f	183	{
29a26a56 EB	184	return NF_HOOK_COND(NFPROTO_IPV6, NF_INET_POST_ROUTING,
	185	net, sk, skb, NULL, skb_dst(skb)->dev,
	186	__xfrm6_output,
5596732f	187	!(IP6CB(skb)->flags & IP6SKB_REROUTED));
16a6677f	188	}