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_tunnel_check_size(struct sk_buff *skb)
 18{
 19	int mtu, ret = 0;
 20
 21	if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
 22		goto out;
 23
 24	if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->ignore_df)
 25		goto out;
 26
 27	mtu = dst_mtu(skb_dst(skb));
 28	if ((!skb_is_gso(skb) && skb->len > mtu) ||
 29	    (skb_is_gso(skb) &&
 30	     !skb_gso_validate_network_len(skb, ip_skb_dst_mtu(skb->sk, skb)))) {
 31		skb->protocol = htons(ETH_P_IP);
 32
 33		if (skb->sk)
 34			xfrm_local_error(skb, mtu);
 35		else
 36			icmp_send(skb, ICMP_DEST_UNREACH,
 37				  ICMP_FRAG_NEEDED, htonl(mtu));
 38		ret = -EMSGSIZE;
 39	}
 40out:
 41	return ret;
 42}
 43
 44int xfrm4_extract_output(struct xfrm_state *x, struct sk_buff *skb)
 45{
 46	int err;
 47
 48	err = xfrm4_tunnel_check_size(skb);
 49	if (err)
 50		return err;
 51
 52	XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol;
 53
 54	return xfrm4_extract_header(skb);
 55}
 56
 57int xfrm4_output_finish(struct sock *sk, struct sk_buff *skb)
 58{
 59	memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
 60
 61#ifdef CONFIG_NETFILTER
 62	IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
 63#endif
 64
 65	return xfrm_output(sk, skb);
 66}
 67
 68static int __xfrm4_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 69{
 
 70	struct xfrm_state *x = skb_dst(skb)->xfrm;
 71	const struct xfrm_state_afinfo *afinfo;
 72	int ret = -EAFNOSUPPORT;
 73
 74#ifdef CONFIG_NETFILTER
 75	if (!x) {
 76		IPCB(skb)->flags |= IPSKB_REROUTED;
 77		return dst_output(net, sk, skb);
 78	}
 79#endif
 80
 81	rcu_read_lock();
 82	afinfo = xfrm_state_afinfo_get_rcu(x->outer_mode.family);
 83	if (likely(afinfo))
 84		ret = afinfo->output_finish(sk, skb);
 85	else
 86		kfree_skb(skb);
 87	rcu_read_unlock();
 88
 89	return ret;
 90}
 91
 92int xfrm4_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 93{
 94	return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
 95			    net, sk, skb, NULL, skb_dst(skb)->dev,
 96			    __xfrm4_output,
 97			    !(IPCB(skb)->flags & IPSKB_REROUTED));
 98}
 99
100void xfrm4_local_error(struct sk_buff *skb, u32 mtu)
101{
102	struct iphdr *hdr;
103
104	hdr = skb->encapsulation ? inner_ip_hdr(skb) : ip_hdr(skb);
105	ip_local_error(skb->sk, EMSGSIZE, hdr->daddr,
106		       inet_sk(skb->sk)->inet_dport, mtu);
107}

 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}