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));
32 if ((!skb_is_gso(skb) && skb->len > mtu) ||
34 !skb_gso_validate_network_len(skb, ip_skb_dst_mtu(skb->sk, skb)))) {
35 skb->protocol = htons(ETH_P_IP);
38 xfrm_local_error(skb, mtu);
40 icmp_send(skb, ICMP_DEST_UNREACH,
41 ICMP_FRAG_NEEDED, htonl(mtu));
48 int xfrm4_extract_output(struct xfrm_state *x, struct sk_buff *skb)
52 err = xfrm4_tunnel_check_size(skb);
56 XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol;
58 return xfrm4_extract_header(skb);
61 int xfrm4_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
65 err = xfrm_inner_extract_output(x, skb);
69 IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE;
70 skb->protocol = htons(ETH_P_IP);
72 return x->outer_mode->output2(x, skb);
74 EXPORT_SYMBOL(xfrm4_prepare_output);
76 int xfrm4_output_finish(struct sock *sk, struct sk_buff *skb)
78 memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
80 IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
82 return xfrm_output(sk, skb);
85 static int __xfrm4_output(struct net *net, struct sock *sk, struct sk_buff *skb)
87 struct xfrm_state *x = skb_dst(skb)->xfrm;
89 #ifdef CONFIG_NETFILTER
91 IPCB(skb)->flags |= IPSKB_REROUTED;
92 return dst_output(net, sk, skb);
96 return x->outer_mode->afinfo->output_finish(sk, skb);
99 int xfrm4_output(struct net *net, struct sock *sk, struct sk_buff *skb)
101 return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
102 net, sk, skb, NULL, skb_dst(skb)->dev,
104 !(IPCB(skb)->flags & IPSKB_REROUTED));
107 void xfrm4_local_error(struct sk_buff *skb, u32 mtu)
111 hdr = skb->encapsulation ? inner_ip_hdr(skb) : ip_hdr(skb);
112 ip_local_error(skb->sk, EMSGSIZE, hdr->daddr,
113 inet_sk(skb->sk)->inet_dport, mtu);