[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;
	struct dst_entry *dst;

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

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

	dst = skb_dst(skb);
	mtu = dst_mtu(dst);
	if (skb->len > mtu) {
		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;

	memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
	IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED;

	skb->protocol = htons(ETH_P_IP);

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

static int xfrm4_output_finish(struct sk_buff *skb)
{
#ifdef CONFIG_NETFILTER
	if (!skb_dst(skb)->xfrm) {
		IPCB(skb)->flags |= IPSKB_REROUTED;
		return dst_output(skb);
	}

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

	skb->protocol = htons(ETH_P_IP);
	return xfrm_output(skb);
}

int xfrm4_output(struct sk_buff *skb)
{
	return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, skb,
			    NULL, skb_dst(skb)->dev, xfrm4_output_finish,
			    !(IPCB(skb)->flags & IPSKB_REROUTED));
}
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;
	24	struct dst_entry *dst;
1da177e4 LT	25
	26	if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
	27	goto out;
	28
eddc9ec5	29	if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) \|\| skb->local_df)
1da177e4 LT	30	goto out;
1da177e4 LT	31
adf30907	32	dst = skb_dst(skb);
1da177e4 LT	33	mtu = dst_mtu(dst);
	34	if (skb->len > mtu) {
	35	icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
	36	ret = -EMSGSIZE;
	37	}
	38	out:
	39	return ret;
	40	}
	41
36cf9acf HX	42	int xfrm4_extract_output(struct xfrm_state x, struct sk_buff skb)
	43	{
	44	int err;
	45
	46	err = xfrm4_tunnel_check_size(skb);
	47	if (err)
	48	return err;
	49
60d5fcfb HX	50	XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol;
60d5fcfb HX	51
36cf9acf HX	52	return xfrm4_extract_header(skb);
	53	}
	54
	55	int xfrm4_prepare_output(struct xfrm_state x, struct sk_buff skb)
	56	{
	57	int err;
	58
df9dcb45	59	err = xfrm_inner_extract_output(x, skb);
36cf9acf HX	60	if (err)
	61	return err;
	62
	63	memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
862b82c6	64	IPCB(skb)->flags \|= IPSKB_XFRM_TUNNEL_SIZE \| IPSKB_XFRM_TRANSFORMED;
36cf9acf HX	65
	66	skb->protocol = htons(ETH_P_IP);
	67
	68	return x->outer_mode->output2(x, skb);
	69	}
	70	EXPORT_SYMBOL(xfrm4_prepare_output);
	71
09b8f7a9 HX	72	static int xfrm4_output_finish(struct sk_buff *skb)
09b8f7a9 HX	73	{
09b8f7a9	74	#ifdef CONFIG_NETFILTER
adf30907	75	if (!skb_dst(skb)->xfrm) {
09b8f7a9 HX	76	IPCB(skb)->flags \|= IPSKB_REROUTED;
	77	return dst_output(skb);
	78	}
09b8f7a9	79
862b82c6 HX	80	IPCB(skb)->flags \|= IPSKB_XFRM_TRANSFORMED;
862b82c6 HX	81	#endif
09b8f7a9 HX	82
09b8f7a9 HX	83	skb->protocol = htons(ETH_P_IP);
862b82c6	84	return xfrm_output(skb);
09b8f7a9 HX	85	}
09b8f7a9 HX	86
16a6677f PM	87	int xfrm4_output(struct sk_buff *skb)
16a6677f PM	88	{
9bbc768a	89	return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, skb,
adf30907	90	NULL, skb_dst(skb)->dev, xfrm4_output_finish,
48d5cad8	91	!(IPCB(skb)->flags & IPSKB_REROUTED));
16a6677f	92	}