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
17static 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
31int 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
39void 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