2 * xfrm6_mode_tunnel.c - Tunnel mode encapsulation for IPv6.
4 * Copyright (C) 2002 USAGI/WIDE Project
5 * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
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>
15 #include <net/inet_ecn.h>
19 static inline void ipip6_ecn_decapsulate(struct sk_buff
*skb
)
21 struct ipv6hdr
*outer_iph
= skb
->nh
.ipv6h
;
22 struct ipv6hdr
*inner_iph
= skb
->h
.ipv6h
;
24 if (INET_ECN_is_ce(ipv6_get_dsfield(outer_iph
)))
25 IP6_ECN_set_ce(inner_iph
);
28 static inline void ip6ip_ecn_decapsulate(struct sk_buff
*skb
)
30 if (INET_ECN_is_ce(ipv6_get_dsfield(skb
->nh
.ipv6h
)))
31 IP_ECN_set_ce(skb
->h
.ipiph
);
34 /* Add encapsulation header.
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:
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.
46 static int xfrm6_tunnel_output(struct xfrm_state
*x
, struct sk_buff
*skb
)
48 struct dst_entry
*dst
= skb
->dst
;
49 struct xfrm_dst
*xdst
= (struct xfrm_dst
*)dst
;
50 struct ipv6hdr
*iph
, *top_iph
;
53 skb_push(skb
, x
->props
.header_len
);
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;
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
;
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
;
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
);
86 static int xfrm6_tunnel_input(struct xfrm_state
*x
, struct sk_buff
*skb
)
90 if (skb
->nh
.raw
[IP6CB(skb
)->nhoff
] != IPPROTO_IPV6
91 && skb
->nh
.raw
[IP6CB(skb
)->nhoff
] != IPPROTO_IPIP
)
93 if (!pskb_may_pull(skb
, sizeof(struct ipv6hdr
)))
96 if (skb_cloned(skb
) &&
97 (err
= pskb_expand_head(skb
, 0, 0, GFP_ATOMIC
)))
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
);
106 if (!(x
->props
.flags
& XFRM_STATE_NOECN
))
107 ip6ip_ecn_decapsulate(skb
);
108 skb
->protocol
= htons(ETH_P_IP
);
110 skb
->mac
.raw
= memmove(skb
->data
- skb
->mac_len
,
111 skb
->mac
.raw
, skb
->mac_len
);
112 skb
->nh
.raw
= skb
->data
;
119 static 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
,
126 static int __init
xfrm6_tunnel_init(void)
128 return xfrm_register_mode(&xfrm6_tunnel_mode
, AF_INET6
);
131 static void __exit
xfrm6_tunnel_exit(void)
135 err
= xfrm_unregister_mode(&xfrm6_tunnel_mode
, AF_INET6
);
139 module_init(xfrm6_tunnel_init
);
140 module_exit(xfrm6_tunnel_exit
);
141 MODULE_LICENSE("GPL");
142 MODULE_ALIAS_XFRM_MODE(AF_INET6
, XFRM_MODE_TUNNEL
);