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(pf: NFPROTO_IPV4, hook: NF_INET_POST_ROUTING,
34 net, sk, skb, in: skb->dev, out: skb_dst_dev(skb),
35 okfn: __xfrm4_output,
36 cond: !(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(sk: skb->sk, EMSGSIZE, daddr: hdr->daddr,
45 inet_sk(skb->sk)->inet_dport, info: mtu);
46}
47