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7#include <linux/init.h>
8#include <linux/kernel.h>
9#include <linux/module.h>
10#include <linux/skbuff.h>
11#include <linux/stringify.h>
12#include <net/dst.h>
13#include <net/ip.h>
14#include <net/xfrm.h>
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19
20
21static int xfrm4_transport_output(struct xfrm_state *x, struct sk_buff *skb)
22{
23 struct iphdr *iph = ip_hdr(skb);
24 int ihl = iph->ihl * 4;
25
26 skb_set_network_header(skb, -x->props.header_len);
27 skb->mac_header = skb->network_header +
28 offsetof(struct iphdr, protocol);
29 skb->transport_header = skb->network_header + ihl;
30 __skb_pull(skb, ihl);
31 memmove(skb_network_header(skb), iph, ihl);
32 return 0;
33}
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41
42
43static int xfrm4_transport_input(struct xfrm_state *x, struct sk_buff *skb)
44{
45 int ihl = skb->data - skb_transport_header(skb);
46
47 if (skb->transport_header != skb->network_header) {
48 memmove(skb_transport_header(skb),
49 skb_network_header(skb), ihl);
50 skb->network_header = skb->transport_header;
51 }
52 ip_hdr(skb)->tot_len = htons(skb->len + ihl);
53 skb_reset_transport_header(skb);
54 return 0;
55}
56
57static struct xfrm_mode xfrm4_transport_mode = {
58 .input = xfrm4_transport_input,
59 .output = xfrm4_transport_output,
60 .owner = THIS_MODULE,
61 .encap = XFRM_MODE_TRANSPORT,
62};
63
64static int __init xfrm4_transport_init(void)
65{
66 return xfrm_register_mode(&xfrm4_transport_mode, AF_INET);
67}
68
69static void __exit xfrm4_transport_exit(void)
70{
71 int err;
72
73 err = xfrm_unregister_mode(&xfrm4_transport_mode, AF_INET);
74 BUG_ON(err);
75}
76
77module_init(xfrm4_transport_init);
78module_exit(xfrm4_transport_exit);
79MODULE_LICENSE("GPL");
80MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_TRANSPORT);
81