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