Commit | Line | Data |
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b59f45d0 HX |
1 | /* |
2 | * xfrm6_mode_transport.c - Transport 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/dst.h> | |
14 | #include <net/ipv6.h> | |
15 | #include <net/xfrm.h> | |
16 | ||
17 | /* Add encapsulation header. | |
18 | * | |
19 | * The IP header and mutable extension headers will be moved forward to make | |
20 | * space for the encapsulation header. | |
21 | * | |
22 | * On exit, skb->h will be set to the start of the encapsulation header to be | |
007f0211 HX |
23 | * filled in by x->type->output and the mac header will be set to the |
24 | * nextheader field of the extension header directly preceding the | |
25 | * encapsulation header, or in its absence, that of the top IP header. | |
26 | * The value of skb->data and the network header will always point to the | |
27 | * top IP header. | |
b59f45d0 | 28 | */ |
eb878e84 | 29 | static int xfrm6_transport_output(struct xfrm_state *x, struct sk_buff *skb) |
b59f45d0 | 30 | { |
b59f45d0 HX |
31 | struct ipv6hdr *iph; |
32 | u8 *prevhdr; | |
33 | int hdr_len; | |
34 | ||
35 | skb_push(skb, x->props.header_len); | |
0660e03f | 36 | iph = ipv6_hdr(skb); |
b59f45d0 | 37 | |
aee5adb4 | 38 | hdr_len = x->type->hdr_offset(x, skb, &prevhdr); |
007f0211 HX |
39 | skb_set_mac_header(skb, (prevhdr - x->props.header_len) - skb->data); |
40 | skb_reset_network_header(skb); | |
967b05f6 | 41 | skb_set_transport_header(skb, hdr_len); |
b59f45d0 HX |
42 | memmove(skb->data, iph, hdr_len); |
43 | return 0; | |
44 | } | |
45 | ||
31a4ab93 HX |
46 | /* Remove encapsulation header. |
47 | * | |
48 | * The IP header will be moved over the top of the encapsulation header. | |
49 | * | |
50 | * On entry, skb->h shall point to where the IP header should be and skb->nh | |
51 | * shall be set to where the IP header currently is. skb->data shall point | |
52 | * to the start of the payload. | |
53 | */ | |
b59f45d0 HX |
54 | static int xfrm6_transport_input(struct xfrm_state *x, struct sk_buff *skb) |
55 | { | |
9c70220b | 56 | int ihl = skb->data - skb_transport_header(skb); |
31a4ab93 | 57 | |
b0e380b1 | 58 | if (skb->transport_header != skb->network_header) { |
9c70220b ACM |
59 | memmove(skb_transport_header(skb), |
60 | skb_network_header(skb), ihl); | |
b0e380b1 | 61 | skb->network_header = skb->transport_header; |
d56f90a7 | 62 | } |
0660e03f | 63 | ipv6_hdr(skb)->payload_len = htons(skb->len + ihl - |
31a4ab93 | 64 | sizeof(struct ipv6hdr)); |
badff6d0 | 65 | skb_reset_transport_header(skb); |
b59f45d0 HX |
66 | return 0; |
67 | } | |
68 | ||
69 | static struct xfrm_mode xfrm6_transport_mode = { | |
70 | .input = xfrm6_transport_input, | |
71 | .output = xfrm6_transport_output, | |
72 | .owner = THIS_MODULE, | |
73 | .encap = XFRM_MODE_TRANSPORT, | |
74 | }; | |
75 | ||
76 | static int __init xfrm6_transport_init(void) | |
77 | { | |
78 | return xfrm_register_mode(&xfrm6_transport_mode, AF_INET6); | |
79 | } | |
80 | ||
81 | static void __exit xfrm6_transport_exit(void) | |
82 | { | |
83 | int err; | |
84 | ||
85 | err = xfrm_unregister_mode(&xfrm6_transport_mode, AF_INET6); | |
86 | BUG_ON(err); | |
87 | } | |
88 | ||
89 | module_init(xfrm6_transport_init); | |
90 | module_exit(xfrm6_transport_exit); | |
91 | MODULE_LICENSE("GPL"); | |
92 | MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TRANSPORT); |