2 * xfrm4_output.c - Common IPsec encapsulation code for IPv4.
3 * Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au>
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.
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>
21 static int xfrm4_tunnel_check_size(struct sk_buff *skb)
24 struct dst_entry *dst;
26 if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
29 if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->local_df)
35 icmp_send(skb, ICMP_DEST_UNREACH, ICMP_FRAG_NEEDED, htonl(mtu));
42 int xfrm4_extract_output(struct xfrm_state *x, struct sk_buff *skb)
46 err = xfrm4_tunnel_check_size(skb);
50 XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol;
52 return xfrm4_extract_header(skb);
55 int xfrm4_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
59 err = xfrm_inner_extract_output(x, skb);
63 memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
64 IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED;
66 skb->protocol = htons(ETH_P_IP);
68 return x->outer_mode->output2(x, skb);
70 EXPORT_SYMBOL(xfrm4_prepare_output);
72 static int xfrm4_output_finish(struct sk_buff *skb)
74 #ifdef CONFIG_NETFILTER
75 if (!skb_dst(skb)->xfrm) {
76 IPCB(skb)->flags |= IPSKB_REROUTED;
77 return dst_output(skb);
80 IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
83 skb->protocol = htons(ETH_P_IP);
84 return xfrm_output(skb);
87 int xfrm4_output(struct sk_buff *skb)
89 return NF_HOOK_COND(PF_INET, NF_INET_POST_ROUTING, skb,
90 NULL, skb_dst(skb)->dev, xfrm4_output_finish,
91 !(IPCB(skb)->flags & IPSKB_REROUTED));