1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * xfrm4_output.c - Common IPsec encapsulation code for IPv4.
4  * Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au>
5  */
6 
7 #include <linux/if_ether.h>
8 #include <linux/kernel.h>
9 #include <linux/module.h>
10 #include <linux/skbuff.h>
11 #include <linux/netfilter_ipv4.h>
12 #include <net/dst.h>
13 #include <net/ip.h>
14 #include <net/xfrm.h>
15 #include <net/icmp.h>
16 
__xfrm4_output(struct net * net,struct sock * sk,struct sk_buff * skb)17 static int __xfrm4_output(struct net *net, struct sock *sk, struct sk_buff *skb)
18 {
19 #ifdef CONFIG_NETFILTER
20 	struct xfrm_state *x = skb_dst(skb)->xfrm;
21 
22 	if (!x) {
23 		IPCB(skb)->flags |= IPSKB_REROUTED;
24 		return dst_output(net, sk, skb);
25 	}
26 #endif
27 
28 	return xfrm_output(sk, skb);
29 }
30 
xfrm4_output(struct net * net,struct sock * sk,struct sk_buff * skb)31 int xfrm4_output(struct net *net, struct sock *sk, struct sk_buff *skb)
32 {
33 	return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
34 			    net, sk, skb, skb->dev, skb_dst(skb)->dev,
35 			    __xfrm4_output,
36 			    !(IPCB(skb)->flags & IPSKB_REROUTED));
37 }
38 
xfrm4_local_error(struct sk_buff * skb,u32 mtu)39 void xfrm4_local_error(struct sk_buff *skb, u32 mtu)
40 {
41 	struct iphdr *hdr;
42 
43 	hdr = skb->encapsulation ? inner_ip_hdr(skb) : ip_hdr(skb);
44 	ip_local_error(skb->sk, EMSGSIZE, hdr->daddr,
45 		       inet_sk(skb->sk)->inet_dport, mtu);
46 }
47