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authorHerbert Xu <herbert@gondor.apana.org.au>2006-05-28 02:05:54 -0400
committerDavid S. Miller <davem@sunset.davemloft.net>2006-06-18 00:28:39 -0400
commitb59f45d0b2878ab76f8053b0973654e6621828ee (patch)
tree40dc5e2ede2620f7935fb3dae0d0eb199851f611 /net/ipv6/xfrm6_mode_tunnel.c
parent546be2405be119ef55467aace45f337a16e5d424 (diff)
[IPSEC] xfrm: Abstract out encapsulation modes
This patch adds the structure xfrm_mode. It is meant to represent the operations carried out by transport/tunnel modes. By doing this we allow additional encapsulation modes to be added without clogging up the xfrm_input/xfrm_output paths. Candidate modes include 4-to-6 tunnel mode, 6-to-4 tunnel mode, and BEET modes. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6/xfrm6_mode_tunnel.c')
-rw-r--r--net/ipv6/xfrm6_mode_tunnel.c121
1 files changed, 121 insertions, 0 deletions
diff --git a/net/ipv6/xfrm6_mode_tunnel.c b/net/ipv6/xfrm6_mode_tunnel.c
new file mode 100644
index 000000000000..8af79be2edca
--- /dev/null
+++ b/net/ipv6/xfrm6_mode_tunnel.c
@@ -0,0 +1,121 @@
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
28/* Add encapsulation header.
29 *
30 * The top IP header will be constructed per RFC 2401. The following fields
31 * in it shall be filled in by x->type->output:
32 * payload_len
33 *
34 * On exit, skb->h will be set to the start of the encapsulation header to be
35 * filled in by x->type->output and skb->nh will be set to the nextheader field
36 * of the extension header directly preceding the encapsulation header, or in
37 * its absence, that of the top IP header. The value of skb->data will always
38 * point to the top IP header.
39 */
40static int xfrm6_tunnel_output(struct sk_buff *skb)
41{
42 struct dst_entry *dst = skb->dst;
43 struct xfrm_state *x = dst->xfrm;
44 struct ipv6hdr *iph, *top_iph;
45 int dsfield;
46
47 skb_push(skb, x->props.header_len);
48 iph = skb->nh.ipv6h;
49
50 skb->nh.raw = skb->data;
51 top_iph = skb->nh.ipv6h;
52 skb->nh.raw = &top_iph->nexthdr;
53 skb->h.ipv6h = top_iph + 1;
54
55 top_iph->version = 6;
56 top_iph->priority = iph->priority;
57 top_iph->flow_lbl[0] = iph->flow_lbl[0];
58 top_iph->flow_lbl[1] = iph->flow_lbl[1];
59 top_iph->flow_lbl[2] = iph->flow_lbl[2];
60 dsfield = ipv6_get_dsfield(top_iph);
61 dsfield = INET_ECN_encapsulate(dsfield, dsfield);
62 if (x->props.flags & XFRM_STATE_NOECN)
63 dsfield &= ~INET_ECN_MASK;
64 ipv6_change_dsfield(top_iph, 0, dsfield);
65 top_iph->nexthdr = IPPROTO_IPV6;
66 top_iph->hop_limit = dst_metric(dst->child, RTAX_HOPLIMIT);
67 ipv6_addr_copy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr);
68 ipv6_addr_copy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr);
69 return 0;
70}
71
72static int xfrm6_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
73{
74 int err = -EINVAL;
75
76 if (skb->nh.raw[IP6CB(skb)->nhoff] != IPPROTO_IPV6)
77 goto out;
78 if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
79 goto out;
80
81 if (skb_cloned(skb) &&
82 (err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC)))
83 goto out;
84
85 if (x->props.flags & XFRM_STATE_DECAP_DSCP)
86 ipv6_copy_dscp(skb->nh.ipv6h, skb->h.ipv6h);
87 if (!(x->props.flags & XFRM_STATE_NOECN))
88 ipip6_ecn_decapsulate(skb);
89 skb->mac.raw = memmove(skb->data - skb->mac_len,
90 skb->mac.raw, skb->mac_len);
91 skb->nh.raw = skb->data;
92 err = 0;
93
94out:
95 return err;
96}
97
98static struct xfrm_mode xfrm6_tunnel_mode = {
99 .input = xfrm6_tunnel_input,
100 .output = xfrm6_tunnel_output,
101 .owner = THIS_MODULE,
102 .encap = XFRM_MODE_TUNNEL,
103};
104
105static int __init xfrm6_tunnel_init(void)
106{
107 return xfrm_register_mode(&xfrm6_tunnel_mode, AF_INET6);
108}
109
110static void __exit xfrm6_tunnel_exit(void)
111{
112 int err;
113
114 err = xfrm_unregister_mode(&xfrm6_tunnel_mode, AF_INET6);
115 BUG_ON(err);
116}
117
118module_init(xfrm6_tunnel_init);
119module_exit(xfrm6_tunnel_exit);
120MODULE_LICENSE("GPL");
121MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TUNNEL);