[linux.git] / net / ipv4 / xfrm4_output.c

/*
 * xfrm4_output.c - Common IPsec encapsulation code for IPv4.
 * 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/netfilter_ipv4.h>
#include <net/dst.h>
#include <net/ip.h>
#include <net/xfrm.h>
#include <net/icmp.h>

static int xfrm4_tunnel_check_size(struct sk_buff *skb)
{
	int mtu, ret = 0;

	if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
		goto out;

	if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->ignore_df)
		goto out;

	mtu = dst_mtu(skb_dst(skb));
	if ((!skb_is_gso(skb) && skb->len > mtu) ||
	    (skb_is_gso(skb) && skb_gso_network_seglen(skb) > ip_skb_dst_mtu(skb->sk, skb))) {
		skb->protocol = htons(ETH_P_IP);

		if (skb->sk)
			xfrm_local_error(skb, mtu);
		else
			icmp_send(skb, ICMP_DEST_UNREACH,
				  ICMP_FRAG_NEEDED, htonl(mtu));
		ret = -EMSGSIZE;
	}
out:
	return ret;
}

int xfrm4_extract_output(struct xfrm_state *x, struct sk_buff *skb)
{
	int err;

	err = xfrm4_tunnel_check_size(skb);
	if (err)
		return err;

	XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol;

	return xfrm4_extract_header(skb);
}

int xfrm4_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
{
	int err;

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

	IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE;
	skb->protocol = htons(ETH_P_IP);

	return x->outer_mode->output2(x, skb);
}
EXPORT_SYMBOL(xfrm4_prepare_output);

int xfrm4_output_finish(struct sock *sk, struct sk_buff *skb)
{
	memset(IPCB(skb), 0, sizeof(*IPCB(skb)));

#ifdef CONFIG_NETFILTER
	IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
#endif

	return xfrm_output(sk, skb);
}

static int __xfrm4_output(struct net *net, struct sock *sk, struct sk_buff *skb)
{
	struct xfrm_state *x = skb_dst(skb)->xfrm;

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

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

int xfrm4_output(struct net *net, struct sock *sk, struct sk_buff *skb)
{
	return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
			    net, sk, skb, NULL, skb_dst(skb)->dev,
			    __xfrm4_output,
			    !(IPCB(skb)->flags & IPSKB_REROUTED));
}

void xfrm4_local_error(struct sk_buff *skb, u32 mtu)
{
	struct iphdr *hdr;

	hdr = skb->encapsulation ? inner_ip_hdr(skb) : ip_hdr(skb);
	ip_local_error(skb->sk, EMSGSIZE, hdr->daddr,
		       inet_sk(skb->sk)->inet_dport, mtu);
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* xfrm4_output.c - Common IPsec encapsulation code for IPv4.
	3	* Copyright (c) 2004 Herbert Xu <[email protected]>
e905a9ed	4	*
1da177e4 LT	5	* This program is free software; you can redistribute it and/or
	6	* modify it under the terms of the GNU General Public License
	7	* as published by the Free Software Foundation; either version
	8	* 2 of the License, or (at your option) any later version.
	9	*/
	10
09b8f7a9 HX	11	#include <linux/if_ether.h>
09b8f7a9 HX	12	#include <linux/kernel.h>
36cf9acf	13	#include <linux/module.h>
1da177e4	14	#include <linux/skbuff.h>
16a6677f	15	#include <linux/netfilter_ipv4.h>
36cf9acf	16	#include <net/dst.h>
1da177e4 LT	17	#include <net/ip.h>
	18	#include <net/xfrm.h>
	19	#include <net/icmp.h>
	20
1da177e4 LT	21	static int xfrm4_tunnel_check_size(struct sk_buff *skb)
	22	{
	23	int mtu, ret = 0;
1da177e4 LT	24
	25	if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
	26	goto out;
	27
60ff7467	28	if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) \|\| skb->ignore_df)
1da177e4 LT	29	goto out;
1da177e4 LT	30
5a25cf1e	31	mtu = dst_mtu(skb_dst(skb));
d77e38e6 SK	32	if ((!skb_is_gso(skb) && skb->len > mtu) \|\|
d77e38e6 SK	33	(skb_is_gso(skb) && skb_gso_network_seglen(skb) > ip_skb_dst_mtu(skb->sk, skb))) {
ca064bd8 SK	34	skb->protocol = htons(ETH_P_IP);
ca064bd8 SK	35
b00897b8	36	if (skb->sk)
628e341f	37	xfrm_local_error(skb, mtu);
b00897b8 SK	38	else
	39	icmp_send(skb, ICMP_DEST_UNREACH,
	40	ICMP_FRAG_NEEDED, htonl(mtu));
1da177e4 LT	41	ret = -EMSGSIZE;
	42	}
	43	out:
	44	return ret;
	45	}
	46
36cf9acf HX	47	int xfrm4_extract_output(struct xfrm_state x, struct sk_buff skb)
	48	{
	49	int err;
	50
	51	err = xfrm4_tunnel_check_size(skb);
	52	if (err)
	53	return err;
	54
60d5fcfb HX	55	XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol;
60d5fcfb HX	56
36cf9acf HX	57	return xfrm4_extract_header(skb);
	58	}
	59
	60	int xfrm4_prepare_output(struct xfrm_state x, struct sk_buff skb)
	61	{
	62	int err;
	63
df9dcb45	64	err = xfrm_inner_extract_output(x, skb);
36cf9acf HX	65	if (err)
	66	return err;
	67
5596732f	68	IPCB(skb)->flags \|= IPSKB_XFRM_TUNNEL_SIZE;
044a832a	69	skb->protocol = htons(ETH_P_IP);
36cf9acf HX	70
	71	return x->outer_mode->output2(x, skb);
	72	}
	73	EXPORT_SYMBOL(xfrm4_prepare_output);
	74
7026b1dd	75	int xfrm4_output_finish(struct sock sk, struct sk_buff skb)
09b8f7a9	76	{
5596732f	77	memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
5596732f SK	78
	79	#ifdef CONFIG_NETFILTER
	80	IPCB(skb)->flags \|= IPSKB_XFRM_TRANSFORMED;
	81	#endif
	82
7026b1dd	83	return xfrm_output(sk, skb);
5596732f SK	84	}
5596732f SK	85
0c4b51f0	86	static int __xfrm4_output(struct net net, struct sock sk, struct sk_buff *skb)
5596732f SK	87	{
	88	struct xfrm_state *x = skb_dst(skb)->xfrm;
	89
09b8f7a9	90	#ifdef CONFIG_NETFILTER
5596732f	91	if (!x) {
09b8f7a9	92	IPCB(skb)->flags \|= IPSKB_REROUTED;
13206b6b	93	return dst_output(net, sk, skb);
09b8f7a9	94	}
862b82c6	95	#endif
09b8f7a9	96
7026b1dd	97	return x->outer_mode->afinfo->output_finish(sk, skb);
09b8f7a9 HX	98	}
09b8f7a9 HX	99
ede2059d	100	int xfrm4_output(struct net net, struct sock sk, struct sk_buff *skb)
16a6677f	101	{
29a26a56 EB	102	return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
	103	net, sk, skb, NULL, skb_dst(skb)->dev,
	104	__xfrm4_output,
48d5cad8	105	!(IPCB(skb)->flags & IPSKB_REROUTED));
16a6677f	106	}
628e341f HFS	107
	108	void xfrm4_local_error(struct sk_buff *skb, u32 mtu)
	109	{
	110	struct iphdr *hdr;
	111
	112	hdr = skb->encapsulation ? inner_ip_hdr(skb) : ip_hdr(skb);
	113	ip_local_error(skb->sk, EMSGSIZE, hdr->daddr,
	114	inet_sk(skb->sk)->inet_dport, mtu);
	115	}