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}

 
  1/*
  2 * xfrm4_output.c - Common IPsec encapsulation code for IPv4.
  3 * Copyright (c) 2004 Herbert Xu <herbert@gondor.apana.org.au>
  4 *
  5 * This program is free software; you can redistribute it and/or
  6 * modify it under the terms of the GNU General Public License
  7 * as published by the Free Software Foundation; either version
  8 * 2 of the License, or (at your option) any later version.
  9 */
 10
 11#include <linux/if_ether.h>
 12#include <linux/kernel.h>
 13#include <linux/module.h>
 14#include <linux/skbuff.h>
 15#include <linux/netfilter_ipv4.h>
 16#include <net/dst.h>
 17#include <net/ip.h>
 18#include <net/xfrm.h>
 19#include <net/icmp.h>
 20
 21static int xfrm4_tunnel_check_size(struct sk_buff *skb)
 22{
 23	int mtu, ret = 0;
 24
 25	if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
 26		goto out;
 27
 28	if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->local_df)
 29		goto out;
 30
 31	mtu = dst_mtu(skb_dst(skb));
 32	if (skb->len > mtu) {
 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_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
 58{
 59	int err;
 60
 61	err = xfrm_inner_extract_output(x, skb);
 62	if (err)
 63		return err;
 64
 65	IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE;
 66
 67	return x->outer_mode->output2(x, skb);
 68}
 69EXPORT_SYMBOL(xfrm4_prepare_output);
 70
 71int xfrm4_output_finish(struct sk_buff *skb)
 72{
 73	memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
 74	skb->protocol = htons(ETH_P_IP);
 75
 76#ifdef CONFIG_NETFILTER
 77	IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
 78#endif
 79
 80	return xfrm_output(skb);
 81}
 82
 83static int __xfrm4_output(struct sk_buff *skb)
 84{
 85	struct xfrm_state *x = skb_dst(skb)->xfrm;
 86
 87#ifdef CONFIG_NETFILTER
 88	if (!x) {
 89		IPCB(skb)->flags |= IPSKB_REROUTED;
 90		return dst_output(skb);
 91	}
 92#endif
 93
 94	return x->outer_mode->afinfo->output_finish(skb);
 95}
 96
 97int xfrm4_output(struct sock *sk, struct sk_buff *skb)
 98{
 99	return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, skb,
100			    NULL, skb_dst(skb)->dev, __xfrm4_output,
 
101			    !(IPCB(skb)->flags & IPSKB_REROUTED));
102}
103
104void xfrm4_local_error(struct sk_buff *skb, u32 mtu)
105{
106	struct iphdr *hdr;
107
108	hdr = skb->encapsulation ? inner_ip_hdr(skb) : ip_hdr(skb);
109	ip_local_error(skb->sk, EMSGSIZE, hdr->daddr,
110		       inet_sk(skb->sk)->inet_dport, mtu);
111}