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 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 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 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