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)
25 if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
28 if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->ignore_df)
31 mtu = dst_mtu(skb_dst(skb));
34 xfrm_local_error(skb, mtu);
36 icmp_send(skb, ICMP_DEST_UNREACH,
37 ICMP_FRAG_NEEDED, htonl(mtu));
44 int xfrm4_extract_output(struct xfrm_state *x, struct sk_buff *skb)
48 err = xfrm4_tunnel_check_size(skb);
52 XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol;
54 return xfrm4_extract_header(skb);
57 int xfrm4_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
61 err = xfrm_inner_extract_output(x, skb);
65 IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE;
66 skb->protocol = htons(ETH_P_IP);
68 return x->outer_mode->output2(x, skb);
70 EXPORT_SYMBOL(xfrm4_prepare_output);
72 int xfrm4_output_finish(struct sock *sk, struct sk_buff *skb)
74 memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
76 #ifdef CONFIG_NETFILTER
77 IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
80 return xfrm_output(sk, skb);
83 static int __xfrm4_output(struct sock *sk, struct sk_buff *skb)
85 struct xfrm_state *x = skb_dst(skb)->xfrm;
87 #ifdef CONFIG_NETFILTER
89 IPCB(skb)->flags |= IPSKB_REROUTED;
90 return dst_output_sk(sk, skb);
94 return x->outer_mode->afinfo->output_finish(sk, skb);
97 int xfrm4_output(struct sock *sk, struct sk_buff *skb)
99 return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, sk, skb,
100 NULL, skb_dst(skb)->dev, __xfrm4_output,
101 !(IPCB(skb)->flags & IPSKB_REROUTED));
104 void xfrm4_local_error(struct sk_buff *skb, u32 mtu)
108 hdr = skb->encapsulation ? inner_ip_hdr(skb) : ip_hdr(skb);
109 ip_local_error(skb->sk, EMSGSIZE, hdr->daddr,
110 inet_sk(skb->sk)->inet_dport, mtu);