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_is_gso(skb) && skb->len > mtu) ||
33 (skb_is_gso(skb) && skb_gso_network_seglen(skb) > ip_skb_dst_mtu(skb->sk, skb))) {
34 skb->protocol = htons(ETH_P_IP);
35
36 if (skb->sk)
37 xfrm_local_error(skb, 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 IPCB(skb)->flags |= IPSKB_XFRM_TUNNEL_SIZE;
69 skb->protocol = htons(ETH_P_IP);
70
71 return x->outer_mode->output2(x, skb);
72}
73EXPORT_SYMBOL(xfrm4_prepare_output);
74
75int xfrm4_output_finish(struct sock *sk, struct sk_buff *skb)
76{
77 memset(IPCB(skb), 0, sizeof(*IPCB(skb)));
78
79#ifdef CONFIG_NETFILTER
80 IPCB(skb)->flags |= IPSKB_XFRM_TRANSFORMED;
81#endif
82
83 return xfrm_output(sk, skb);
84}
85
86static int __xfrm4_output(struct net *net, struct sock *sk, struct sk_buff *skb)
87{
88 struct xfrm_state *x = skb_dst(skb)->xfrm;
89
90#ifdef CONFIG_NETFILTER
91 if (!x) {
92 IPCB(skb)->flags |= IPSKB_REROUTED;
93 return dst_output(net, sk, skb);
94 }
95#endif
96
97 return x->outer_mode->afinfo->output_finish(sk, skb);
98}
99
100int xfrm4_output(struct net *net, struct sock *sk, struct sk_buff *skb)
101{
102 return NF_HOOK_COND(NFPROTO_IPV4, NF_INET_POST_ROUTING,
103 net, sk, skb, NULL, skb_dst(skb)->dev,
104 __xfrm4_output,
105 !(IPCB(skb)->flags & IPSKB_REROUTED));
106}
107
108void xfrm4_local_error(struct sk_buff *skb, u32 mtu)
109{
110 struct iphdr *hdr;
111
112 hdr = skb->encapsulation ? inner_ip_hdr(skb) : ip_hdr(skb);
113 ip_local_error(skb->sk, EMSGSIZE, hdr->daddr,
114 inet_sk(skb->sk)->inet_dport, mtu);
115}