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
ipip6_ecn_decapsulate(struct sk_buff * skb)21 static inline void ipip6_ecn_decapsulate(struct sk_buff *skb)
22 {
23 struct ipv6hdr *inner_iph = ipipv6_hdr(skb);
24
25 if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos))
26 IP6_ECN_set_ce(skb, inner_iph);
27 }
28
29 /* Add encapsulation header.
30 *
31 * The top IP header will be constructed per RFC 2401.
32 */
xfrm6_mode_tunnel_output(struct xfrm_state * x,struct sk_buff * skb)33 static int xfrm6_mode_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
34 {
35 struct dst_entry *dst = skb_dst(skb);
36 struct ipv6hdr *top_iph;
37 int dsfield;
38
39 skb_set_network_header(skb, -x->props.header_len);
40 skb->mac_header = skb->network_header +
41 offsetof(struct ipv6hdr, nexthdr);
42 skb->transport_header = skb->network_header + sizeof(*top_iph);
43 top_iph = ipv6_hdr(skb);
44
45 top_iph->version = 6;
46
47 memcpy(top_iph->flow_lbl, XFRM_MODE_SKB_CB(skb)->flow_lbl,
48 sizeof(top_iph->flow_lbl));
49 top_iph->nexthdr = xfrm_af2proto(skb_dst(skb)->ops->family);
50
51 if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP)
52 dsfield = 0;
53 else
54 dsfield = XFRM_MODE_SKB_CB(skb)->tos;
55 dsfield = INET_ECN_encapsulate(dsfield, XFRM_MODE_SKB_CB(skb)->tos);
56 if (x->props.flags & XFRM_STATE_NOECN)
57 dsfield &= ~INET_ECN_MASK;
58 ipv6_change_dsfield(top_iph, 0, dsfield);
59 top_iph->hop_limit = ip6_dst_hoplimit(dst->child);
60 top_iph->saddr = *(struct in6_addr *)&x->props.saddr;
61 top_iph->daddr = *(struct in6_addr *)&x->id.daddr;
62 return 0;
63 }
64
65 #define for_each_input_rcu(head, handler) \
66 for (handler = rcu_dereference(head); \
67 handler != NULL; \
68 handler = rcu_dereference(handler->next))
69
70
xfrm6_mode_tunnel_input(struct xfrm_state * x,struct sk_buff * skb)71 static int xfrm6_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
72 {
73 int err = -EINVAL;
74
75 if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPV6)
76 goto out;
77 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
78 goto out;
79
80 err = skb_unclone(skb, GFP_ATOMIC);
81 if (err)
82 goto out;
83
84 if (x->props.flags & XFRM_STATE_DECAP_DSCP)
85 ipv6_copy_dscp(ipv6_get_dsfield(ipv6_hdr(skb)),
86 ipipv6_hdr(skb));
87 if (!(x->props.flags & XFRM_STATE_NOECN))
88 ipip6_ecn_decapsulate(skb);
89
90 skb_reset_network_header(skb);
91 skb_mac_header_rebuild(skb);
92
93 err = 0;
94
95 out:
96 return err;
97 }
98
99 static struct xfrm_mode xfrm6_tunnel_mode = {
100 .input2 = xfrm6_mode_tunnel_input,
101 .input = xfrm_prepare_input,
102 .output2 = xfrm6_mode_tunnel_output,
103 .output = xfrm6_prepare_output,
104 .owner = THIS_MODULE,
105 .encap = XFRM_MODE_TUNNEL,
106 .flags = XFRM_MODE_FLAG_TUNNEL,
107 };
108
xfrm6_mode_tunnel_init(void)109 static int __init xfrm6_mode_tunnel_init(void)
110 {
111 return xfrm_register_mode(&xfrm6_tunnel_mode, AF_INET6);
112 }
113
xfrm6_mode_tunnel_exit(void)114 static void __exit xfrm6_mode_tunnel_exit(void)
115 {
116 int err;
117
118 err = xfrm_unregister_mode(&xfrm6_tunnel_mode, AF_INET6);
119 BUG_ON(err);
120 }
121
122 module_init(xfrm6_mode_tunnel_init);
123 module_exit(xfrm6_mode_tunnel_exit);
124 MODULE_LICENSE("GPL");
125 MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TUNNEL);
126