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->ignore_df)
 29		goto out;
 30
 31	mtu = dst_mtu(skb_dst(skb));
 32	if ((!skb_is_gso(skb) && skb->len > mtu) ||
 33	    (skb_is_gso(skb) &&
 34	     !skb_gso_validate_network_len(skb, ip_skb_dst_mtu(skb->sk, skb)))) {
 35		skb->protocol = htons(ETH_P_IP);
 36
 37		if (skb->sk)
 38			xfrm_local_error(skb, mtu);
 39		else
 40			icmp_send(skb, ICMP_DEST_UNREACH,
 41				  ICMP_FRAG_NEEDED, htonl(mtu));
 42		ret = -EMSGSIZE;
 43	}
 44out:
 45	return ret;
 46}
 47
 48int xfrm4_extract_output(struct xfrm_state *x, struct sk_buff *skb)
 49{
 50	int err;
 51
 52	err = xfrm4_tunnel_check_size(skb);
 53	if (err)
 54		return err;
 55
 56	XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol;
 57
 58	return xfrm4_extract_header(skb);
 59}
 60
 61int xfrm4_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
 62{
 63	int err;
 64
 65	err = xfrm_inner_extract_output(x, skb);
 66	if (err)
 67		return err;
 68
 69	IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE;
 70	skb->protocol = htons(ETH_P_IP);
 71
 72	return x->outer_mode->output2(x, skb);
 73}
 74EXPORT_SYMBOL(xfrm4_prepare_output);
 75
 76int xfrm4_output_finish(struct sock *sk, struct sk_buff *skb)
 77{
 78	memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
 79
 80#ifdef CONFIG_NETFILTER
 81	IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
 82#endif
 83
 84	return xfrm_output(sk, skb);
 85}
 86
 87static int __xfrm4_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 88{
 
 89	struct xfrm_state *x = skb_dst(skb)->xfrm;
 90
 91#ifdef CONFIG_NETFILTER
 92	if (!x) {
 93		IPCB(skb)->flags |= IPSKB_REROUTED;
 94		return dst_output(net, sk, skb);
 95	}
 96#endif
 97
 98	return x->outer_mode->afinfo->output_finish(sk, skb);
 99}
100
101int xfrm4_output(struct net *net, struct sock *sk, struct sk_buff *skb)
102{
103	return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
104			    net, sk, skb, NULL, skb_dst(skb)->dev,
105			    __xfrm4_output,
106			    !(IPCB(skb)->flags & IPSKB_REROUTED));
107}
108
109void xfrm4_local_error(struct sk_buff *skb, u32 mtu)
110{
111	struct iphdr *hdr;
112
113	hdr = skb->encapsulation ? inner_ip_hdr(skb) : ip_hdr(skb);
114	ip_local_error(skb->sk, EMSGSIZE, hdr->daddr,
115		       inet_sk(skb->sk)->inet_dport, mtu);
116}

 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}