tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * xfrm6_mode_tunnel.c - Tunnel mode encapsulation for IPv6.
3 *
4 * Copyright (C) 2002 USAGI/WIDE Project
5 * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
6 */
7
8#include <linux/gfp.h>
9#include <linux/init.h>
10#include <linux/kernel.h>
11#include <linux/module.h>
12#include <linux/skbuff.h>
13#include <linux/stringify.h>
14#include <net/dsfield.h>
15#include <net/dst.h>
16#include <net/inet_ecn.h>
17#include <net/ip6_route.h>
18#include <net/ipv6.h>
19#include <net/xfrm.h>
20
21static inline void ipip6_ecn_decapsulate(struct sk_buff *skb)
22{
23 const struct ipv6hdr *outer_iph = ipv6_hdr(skb);
24 struct ipv6hdr *inner_iph = ipipv6_hdr(skb);
25
26 if (INET_ECN_is_ce(ipv6_get_dsfield(outer_iph)))
27 IP6_ECN_set_ce(inner_iph);
28}
29
30/* Add encapsulation header.
31 *
32 * The top IP header will be constructed per RFC 2401.
33 */
34static int xfrm6_mode_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
35{
36 struct dst_entry *dst = skb_dst(skb);
37 struct ipv6hdr *top_iph;
38 int dsfield;
39
40 skb_set_network_header(skb, -x->props.header_len);
41 skb->mac_header = skb->network_header +
42 offsetof(struct ipv6hdr, nexthdr);
43 skb->transport_header = skb->network_header + sizeof(*top_iph);
44 top_iph = ipv6_hdr(skb);
45
46 top_iph->version = 6;
47
48 memcpy(top_iph->flow_lbl, XFRM_MODE_SKB_CB(skb)->flow_lbl,
49 sizeof(top_iph->flow_lbl));
50 top_iph->nexthdr = xfrm_af2proto(skb_dst(skb)->ops->family);
51
52 dsfield = XFRM_MODE_SKB_CB(skb)->tos;
53 dsfield = INET_ECN_encapsulate(dsfield, dsfield);
54 if (x->props.flags & XFRM_STATE_NOECN)
55 dsfield &= ~INET_ECN_MASK;
56 ipv6_change_dsfield(top_iph, 0, dsfield);
57 top_iph->hop_limit = ip6_dst_hoplimit(dst->child);
58 ipv6_addr_copy(&top_iph->saddr, (const struct in6_addr *)&x->props.saddr);
59 ipv6_addr_copy(&top_iph->daddr, (const struct in6_addr *)&x->id.daddr);
60 return 0;
61}
62
63static int xfrm6_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
64{
65 int err = -EINVAL;
66 const unsigned char *old_mac;
67
68 if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPV6)
69 goto out;
70 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
71 goto out;
72
73 if (skb_cloned(skb) &&
74 (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
75 goto out;
76
77 if (x->props.flags & XFRM_STATE_DECAP_DSCP)
78 ipv6_copy_dscp(ipv6_get_dsfield(ipv6_hdr(skb)),
79 ipipv6_hdr(skb));
80 if (!(x->props.flags & XFRM_STATE_NOECN))
81 ipip6_ecn_decapsulate(skb);
82
83 old_mac = skb_mac_header(skb);
84 skb_set_mac_header(skb, -skb->mac_len);
85 memmove(skb_mac_header(skb), old_mac, skb->mac_len);
86 skb_reset_network_header(skb);
87 err = 0;
88
89out:
90 return err;
91}
92
93static struct xfrm_mode xfrm6_tunnel_mode = {
94 .input2 = xfrm6_mode_tunnel_input,
95 .input = xfrm_prepare_input,
96 .output2 = xfrm6_mode_tunnel_output,
97 .output = xfrm6_prepare_output,
98 .owner = THIS_MODULE,
99 .encap = XFRM_MODE_TUNNEL,
100 .flags = XFRM_MODE_FLAG_TUNNEL,
101};
102
103static int __init xfrm6_mode_tunnel_init(void)
104{
105 return xfrm_register_mode(&xfrm6_tunnel_mode, AF_INET6);
106}
107
108static void __exit xfrm6_mode_tunnel_exit(void)
109{
110 int err;
111
112 err = xfrm_unregister_mode(&xfrm6_tunnel_mode, AF_INET6);
113 BUG_ON(err);
114}
115
116module_init(xfrm6_mode_tunnel_init);
117module_exit(xfrm6_mode_tunnel_exit);
118MODULE_LICENSE("GPL");
119MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TUNNEL);