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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/init.h>
9#include <linux/kernel.h>
10#include <linux/module.h>
11#include <linux/skbuff.h>
12#include <linux/stringify.h>
13#include <net/dsfield.h>
14#include <net/dst.h>
15#include <net/inet_ecn.h>
16#include <net/ipv6.h>
17#include <net/xfrm.h>
18
19static inline void ipip6_ecn_decapsulate(struct sk_buff *skb)
20{
21 struct ipv6hdr *outer_iph = skb->nh.ipv6h;
22 struct ipv6hdr *inner_iph = skb->h.ipv6h;
23
24 if (INET_ECN_is_ce(ipv6_get_dsfield(outer_iph)))
25 IP6_ECN_set_ce(inner_iph);
26}
27
28static inline void ip6ip_ecn_decapsulate(struct sk_buff *skb)
29{
30 if (INET_ECN_is_ce(ipv6_get_dsfield(skb->nh.ipv6h)))
31 IP_ECN_set_ce(skb->h.ipiph);
32}
33
34/* Add encapsulation header.
35 *
36 * The top IP header will be constructed per RFC 2401. The following fields
37 * in it shall be filled in by x->type->output:
38 * payload_len
39 *
40 * On exit, skb->h will be set to the start of the encapsulation header to be
41 * filled in by x->type->output and skb->nh will be set to the nextheader field
42 * of the extension header directly preceding the encapsulation header, or in
43 * its absence, that of the top IP header. The value of skb->data will always
44 * point to the top IP header.
45 */
46static int xfrm6_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
47{
48 struct dst_entry *dst = skb->dst;
49 struct xfrm_dst *xdst = (struct xfrm_dst*)dst;
50 struct ipv6hdr *iph, *top_iph;
51 int dsfield;
52
53 skb_push(skb, x->props.header_len);
54 iph = skb->nh.ipv6h;
55
56 skb->nh.raw = skb->data;
57 top_iph = skb->nh.ipv6h;
58 skb->nh.raw = &top_iph->nexthdr;
59 skb->h.ipv6h = top_iph + 1;
60
61 top_iph->version = 6;
62 if (xdst->route->ops->family == AF_INET6) {
63 top_iph->priority = iph->priority;
64 top_iph->flow_lbl[0] = iph->flow_lbl[0];
65 top_iph->flow_lbl[1] = iph->flow_lbl[1];
66 top_iph->flow_lbl[2] = iph->flow_lbl[2];
67 top_iph->nexthdr = IPPROTO_IPV6;
68 } else {
69 top_iph->priority = 0;
70 top_iph->flow_lbl[0] = 0;
71 top_iph->flow_lbl[1] = 0;
72 top_iph->flow_lbl[2] = 0;
73 top_iph->nexthdr = IPPROTO_IPIP;
74 }
75 dsfield = ipv6_get_dsfield(top_iph);
76 dsfield = INET_ECN_encapsulate(dsfield, dsfield);
77 if (x->props.flags & XFRM_STATE_NOECN)
78 dsfield &= ~INET_ECN_MASK;
79 ipv6_change_dsfield(top_iph, 0, dsfield);
80 top_iph->hop_limit = dst_metric(dst->child, RTAX_HOPLIMIT);
81 ipv6_addr_copy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr);
82 ipv6_addr_copy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr);
83 return 0;
84}
85
86static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
87{
88 int err = -EINVAL;
89
90 if (skb->nh.raw[IP6CB(skb)->nhoff] != IPPROTO_IPV6
91 && skb->nh.raw[IP6CB(skb)->nhoff] != IPPROTO_IPIP)
92 goto out;
93 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
94 goto out;
95
96 if (skb_cloned(skb) &&
97 (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
98 goto out;
99
100 if (skb->nh.raw[IP6CB(skb)->nhoff] == IPPROTO_IPV6) {
101 if (x->props.flags & XFRM_STATE_DECAP_DSCP)
102 ipv6_copy_dscp(skb->nh.ipv6h, skb->h.ipv6h);
103 if (!(x->props.flags & XFRM_STATE_NOECN))
104 ipip6_ecn_decapsulate(skb);
105 } else {
106 if (!(x->props.flags & XFRM_STATE_NOECN))
107 ip6ip_ecn_decapsulate(skb);
108 skb->protocol = htons(ETH_P_IP);
109 }
110 skb->mac.raw = memmove(skb->data - skb->mac_len,
111 skb->mac.raw, skb->mac_len);
112 skb->nh.raw = skb->data;
113 err = 0;
114
115out:
116 return err;
117}
118
119static struct xfrm_mode xfrm6_tunnel_mode = {
120 .input = xfrm6_tunnel_input,
121 .output = xfrm6_tunnel_output,
122 .owner = THIS_MODULE,
123 .encap = XFRM_MODE_TUNNEL,
124};
125
126static int __init xfrm6_tunnel_init(void)
127{
128 return xfrm_register_mode(&xfrm6_tunnel_mode, AF_INET6);
129}
130
131static void __exit xfrm6_tunnel_exit(void)
132{
133 int err;
134
135 err = xfrm_unregister_mode(&xfrm6_tunnel_mode, AF_INET6);
136 BUG_ON(err);
137}
138
139module_init(xfrm6_tunnel_init);
140module_exit(xfrm6_tunnel_exit);
141MODULE_LICENSE("GPL");
142MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TUNNEL);