[people/ms/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->local_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;

	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);

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 sock *sk, struct sk_buff *skb)
{
	struct dst_entry *dst = skb_dst(skb);
	struct xfrm_state *x = dst->xfrm;

	return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, skb,
			    NULL, dst->dev,
			    x->outer_mode->afinfo->output_finish,
			    !(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 <herbert@gondor.apana.org.au>
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
eddc9ec5	28	if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) \|\| skb->local_df)
1da177e4 LT	29	goto out;
1da177e4 LT	30
5a25cf1e	31	mtu = dst_mtu(skb_dst(skb));
1da177e4	32	if (skb->len > mtu) {
b00897b8	33	if (skb->sk)
628e341f	34	xfrm_local_error(skb, mtu);
b00897b8 SK	35	else
	36	icmp_send(skb, ICMP_DEST_UNREACH,
	37	ICMP_FRAG_NEEDED, htonl(mtu));
1da177e4 LT	38	ret = -EMSGSIZE;
	39	}
	40	out:
	41	return ret;
	42	}
	43
36cf9acf HX	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
60d5fcfb HX	52	XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol;
60d5fcfb HX	53
36cf9acf HX	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
df9dcb45	61	err = xfrm_inner_extract_output(x, skb);
36cf9acf HX	62	if (err)
	63	return err;
	64
	65	memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
862b82c6	66	IPCB(skb)->flags \|= IPSKB_XFRM_TUNNEL_SIZE \| IPSKB_XFRM_TRANSFORMED;
36cf9acf HX	67
	68	skb->protocol = htons(ETH_P_IP);
	69
	70	return x->outer_mode->output2(x, skb);
	71	}
	72	EXPORT_SYMBOL(xfrm4_prepare_output);
	73
43a4dea4	74	int xfrm4_output_finish(struct sk_buff *skb)
09b8f7a9	75	{
09b8f7a9	76	#ifdef CONFIG_NETFILTER
adf30907	77	if (!skb_dst(skb)->xfrm) {
09b8f7a9 HX	78	IPCB(skb)->flags \|= IPSKB_REROUTED;
	79	return dst_output(skb);
	80	}
09b8f7a9	81
862b82c6 HX	82	IPCB(skb)->flags \|= IPSKB_XFRM_TRANSFORMED;
862b82c6 HX	83	#endif
09b8f7a9 HX	84
09b8f7a9 HX	85	skb->protocol = htons(ETH_P_IP);
862b82c6	86	return xfrm_output(skb);
09b8f7a9 HX	87	}
09b8f7a9 HX	88
aad88724	89	int xfrm4_output(struct sock sk, struct sk_buff skb)
16a6677f	90	{
43a4dea4 SK	91	struct dst_entry *dst = skb_dst(skb);
	92	struct xfrm_state *x = dst->xfrm;
	93
9bbc768a	94	return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, skb,
43a4dea4 SK	95	NULL, dst->dev,
43a4dea4 SK	96	x->outer_mode->afinfo->output_finish,
48d5cad8	97	!(IPCB(skb)->flags & IPSKB_REROUTED));
16a6677f	98	}
628e341f HFS	99
	100	void xfrm4_local_error(struct sk_buff *skb, u32 mtu)
	101	{
	102	struct iphdr *hdr;
	103
	104	hdr = skb->encapsulation ? inner_ip_hdr(skb) : ip_hdr(skb);
	105	ip_local_error(skb->sk, EMSGSIZE, hdr->daddr,
	106	inet_sk(skb->sk)->inet_dport, mtu);
	107	}