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	struct dst_entry *dst;
 25
 26	if (IPCB(skb)->flags & IPSKB_XFRM_TUNNEL_SIZE)
 27		goto out;
 28
 29	if (!(ip_hdr(skb)->frag_off & htons(IP_DF)) || skb->local_df)
 30		goto out;
 31
 32	dst = skb_dst(skb);
 33	mtu = dst_mtu(dst);
 34	if (skb->len > mtu) {
 35		if (skb->sk)
 36			ip_local_error(skb->sk, EMSGSIZE, ip_hdr(skb)->daddr,
 37				       inet_sk(skb->sk)->inet_dport, mtu);
 38		else
 39			icmp_send(skb, ICMP_DEST_UNREACH,
 40				  ICMP_FRAG_NEEDED, htonl(mtu));
 41		ret = -EMSGSIZE;
 42	}
 43out:
 44	return ret;
 45}
 46
 47int xfrm4_extract_output(struct xfrm_state *x, struct sk_buff *skb)
 48{
 49	int err;
 50
 51	err = xfrm4_tunnel_check_size(skb);
 52	if (err)
 53		return err;
 54
 55	XFRM_MODE_SKB_CB(skb)->protocol = ip_hdr(skb)->protocol;
 56
 57	return xfrm4_extract_header(skb);
 58}
 59
 60int xfrm4_prepare_output(struct xfrm_state *x, struct sk_buff *skb)
 61{
 62	int err;
 63
 64	err = xfrm_inner_extract_output(x, skb);
 65	if (err)
 66		return err;
 67
 68	memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
 69	IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE | IPSKB_XFRM_TRANSFORMED;
 70
 71	skb->protocol = htons(ETH_P_IP);
 72
 73	return x->outer_mode->output2(x, skb);
 74}
 75EXPORT_SYMBOL(xfrm4_prepare_output);
 76
 77int xfrm4_output_finish(struct sk_buff *skb)
 78{
 79#ifdef CONFIG_NETFILTER
 80	if (!skb_dst(skb)->xfrm) {
 81		IPCB(skb)->flags |= IPSKB_REROUTED;
 82		return dst_output(skb);
 83	}
 84
 85	IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
 86#endif
 87
 88	skb->protocol = htons(ETH_P_IP);
 89	return xfrm_output(skb);
 90}
 91
 92int xfrm4_output(struct sk_buff *skb)
 93{
 94	struct dst_entry *dst = skb_dst(skb);
 95	struct xfrm_state *x = dst->xfrm;
 96
 97	return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING, skb,
 98			    NULL, dst->dev,
 99			    x->outer_mode->afinfo->output_finish,
100			    !(IPCB(skb)->flags & IPSKB_REROUTED));
101}