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

/*
 * xfrm4_output.c - Common IPsec encapsulation code for IPv4.
 * Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au>
 *
 * 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->len > mtu) {
		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
	1	/*
	2	* xfrm4_output.c - Common IPsec encapsulation code for IPv4.
	3	* Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au>
	4	*
	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
	11	#include <linux/if_ether.h>
	12	#include <linux/kernel.h>
	13	#include <linux/module.h>
	14	#include <linux/skbuff.h>
	15	#include <linux/netfilter_ipv4.h>
	16	#include <net/dst.h>
	17	#include <net/ip.h>
	18	#include <net/xfrm.h>
	19	#include <net/icmp.h>
	20
	21	static int xfrm4_tunnel_check_size(struct sk_buff *skb)
	22	{
	23	int mtu, ret = 0;
	24
	25	if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
	26	goto out;
	27
	28	if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) \|\| skb->ignore_df)
	29	goto out;
	30
	31	mtu = dst_mtu(skb_dst(skb));
	32	if (skb->len > mtu) {
	33	skb->protocol = htons(ETH_P_IP);
	34
	35	if (skb->sk)
	36	xfrm_local_error(skb, mtu);
	37	else
	38	icmp_send(skb, ICMP_DEST_UNREACH,
	39	ICMP_FRAG_NEEDED, htonl(mtu));
	40	ret = -EMSGSIZE;
	41	}
	42	out:
	43	return ret;
	44	}
	45
	46	int xfrm4_extract_output(struct xfrm_state x, struct sk_buff skb)
	47	{
	48	int err;
	49
	50	err = xfrm4_tunnel_check_size(skb);
	51	if (err)
	52	return err;
	53
	54	XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol;
	55
	56	return xfrm4_extract_header(skb);
	57	}
	58
	59	int xfrm4_prepare_output(struct xfrm_state x, struct sk_buff skb)
	60	{
	61	int err;
	62
	63	err = xfrm_inner_extract_output(x, skb);
	64	if (err)
	65	return err;
	66
	67	IPCB(skb)->flags \|= IPSKB_XFRM_TUNNEL_SIZE;
	68	skb->protocol = htons(ETH_P_IP);
	69
	70	return x->outer_mode->output2(x, skb);
	71	}
	72	EXPORT_SYMBOL(xfrm4_prepare_output);
	73
	74	int xfrm4_output_finish(struct sock sk, struct sk_buff skb)
	75	{
	76	memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
	77
	78	#ifdef CONFIG_NETFILTER
	79	IPCB(skb)->flags \|= IPSKB_XFRM_TRANSFORMED;
	80	#endif
	81
	82	return xfrm_output(sk, skb);
	83	}
	84
	85	static int __xfrm4_output(struct net net, struct sock sk, struct sk_buff *skb)
	86	{
	87	struct xfrm_state *x = skb_dst(skb)->xfrm;
	88
	89	#ifdef CONFIG_NETFILTER
	90	if (!x) {
	91	IPCB(skb)->flags \|= IPSKB_REROUTED;
	92	return dst_output(net, sk, skb);
	93	}
	94	#endif
	95
	96	return x->outer_mode->afinfo->output_finish(sk, skb);
	97	}
	98
	99	int xfrm4_output(struct net net, struct sock sk, struct sk_buff *skb)
	100	{
	101	return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
	102	net, sk, skb, NULL, skb_dst(skb)->dev,
	103	__xfrm4_output,
	104	!(IPCB(skb)->flags & IPSKB_REROUTED));
	105	}
	106
	107	void xfrm4_local_error(struct sk_buff *skb, u32 mtu)
	108	{
	109	struct iphdr *hdr;
	110
	111	hdr = skb->encapsulation ? inner_ip_hdr(skb) : ip_hdr(skb);
	112	ip_local_error(skb->sk, EMSGSIZE, hdr->daddr,
	113	inet_sk(skb->sk)->inet_dport, mtu);
	114	}