93 lines
2.1 KiB
C
93 lines
2.1 KiB
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;
|
|
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));
|
|
}
|