[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) {
		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 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(sk, skb);
	}
#endif

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

int xfrm4_output(struct sock *sk, struct sk_buff *skb)
{
	struct net *net = dev_net(skb_dst(skb)->dev);
	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	if (skb->sk)
	34	xfrm_local_error(skb, mtu);
	35	else
	36	icmp_send(skb, ICMP_DEST_UNREACH,
	37	ICMP_FRAG_NEEDED, htonl(mtu));
	38	ret = -EMSGSIZE;
	39	}
	40	out:
	41	return ret;
	42	}
	43
	44	int xfrm4_extract_output(struct xfrm_state x, struct sk_buff skb)
	45	{
	46	int err;
	47
	48	err = xfrm4_tunnel_check_size(skb);
	49	if (err)
	50	return err;
	51
	52	XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol;
	53
	54	return xfrm4_extract_header(skb);
	55	}
	56
	57	int xfrm4_prepare_output(struct xfrm_state x, struct sk_buff skb)
	58	{
	59	int err;
	60
	61	err = xfrm_inner_extract_output(x, skb);
	62	if (err)
	63	return err;
	64
	65	IPCB(skb)->flags \|= IPSKB_XFRM_TUNNEL_SIZE;
	66	skb->protocol = htons(ETH_P_IP);
	67
	68	return x->outer_mode->output2(x, skb);
	69	}
	70	EXPORT_SYMBOL(xfrm4_prepare_output);
	71
	72	int xfrm4_output_finish(struct sock sk, struct sk_buff skb)
	73	{
	74	memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
	75
	76	#ifdef CONFIG_NETFILTER
	77	IPCB(skb)->flags \|= IPSKB_XFRM_TRANSFORMED;
	78	#endif
	79
	80	return xfrm_output(sk, skb);
	81	}
	82
	83	static int __xfrm4_output(struct sock sk, struct sk_buff skb)
	84	{
	85	struct xfrm_state *x = skb_dst(skb)->xfrm;
	86
	87	#ifdef CONFIG_NETFILTER
	88	if (!x) {
	89	IPCB(skb)->flags \|= IPSKB_REROUTED;
	90	return dst_output(sk, skb);
	91	}
	92	#endif
	93
	94	return x->outer_mode->afinfo->output_finish(sk, skb);
	95	}
	96
	97	int xfrm4_output(struct sock sk, struct sk_buff skb)
	98	{
	99	struct net *net = dev_net(skb_dst(skb)->dev);
	100	return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
	101	net, sk, skb, NULL, skb_dst(skb)->dev,
	102	__xfrm4_output,
	103	!(IPCB(skb)->flags & IPSKB_REROUTED));
	104	}
	105
	106	void xfrm4_local_error(struct sk_buff *skb, u32 mtu)
	107	{
	108	struct iphdr *hdr;
	109
	110	hdr = skb->encapsulation ? inner_ip_hdr(skb) : ip_hdr(skb);
	111	ip_local_error(skb->sk, EMSGSIZE, hdr->daddr,
	112	inet_sk(skb->sk)->inet_dport, mtu);
	113	}