88 lines
2.4 KiB
C
88 lines
2.4 KiB
C
/*
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* xfrm6_mode_transport.c - Transport mode encapsulation for IPv6.
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*
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* Copyright (C) 2002 USAGI/WIDE Project
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* Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
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*/
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/stringify.h>
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#include <net/dst.h>
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#include <net/ipv6.h>
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#include <net/xfrm.h>
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/* Add encapsulation header.
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*
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* The IP header and mutable extension headers will be moved forward to make
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* space for the encapsulation header.
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*
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* On exit, skb->h will be set to the start of the encapsulation header to be
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* filled in by x->type->output and skb->nh will be set to the nextheader field
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* of the extension header directly preceding the encapsulation header, or in
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* its absence, that of the top IP header. The value of skb->data will always
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* point to the top IP header.
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*/
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static int xfrm6_transport_output(struct xfrm_state *x, struct sk_buff *skb)
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{
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struct ipv6hdr *iph;
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u8 *prevhdr;
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int hdr_len;
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skb_push(skb, x->props.header_len);
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iph = skb->nh.ipv6h;
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hdr_len = x->type->hdr_offset(x, skb, &prevhdr);
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skb->nh.raw = prevhdr - x->props.header_len;
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skb->h.raw = skb->data + hdr_len;
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memmove(skb->data, iph, hdr_len);
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return 0;
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}
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/* Remove encapsulation header.
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*
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* The IP header will be moved over the top of the encapsulation header.
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*
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* On entry, skb->h shall point to where the IP header should be and skb->nh
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* shall be set to where the IP header currently is. skb->data shall point
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* to the start of the payload.
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*/
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static int xfrm6_transport_input(struct xfrm_state *x, struct sk_buff *skb)
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{
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int ihl = skb->data - skb->h.raw;
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if (skb->h.raw != skb->nh.raw)
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skb->nh.raw = memmove(skb->h.raw, skb->nh.raw, ihl);
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skb->nh.ipv6h->payload_len = htons(skb->len + ihl -
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sizeof(struct ipv6hdr));
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skb->h.raw = skb->data;
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return 0;
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}
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static struct xfrm_mode xfrm6_transport_mode = {
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.input = xfrm6_transport_input,
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.output = xfrm6_transport_output,
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.owner = THIS_MODULE,
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.encap = XFRM_MODE_TRANSPORT,
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};
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static int __init xfrm6_transport_init(void)
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{
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return xfrm_register_mode(&xfrm6_transport_mode, AF_INET6);
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}
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static void __exit xfrm6_transport_exit(void)
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{
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int err;
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err = xfrm_unregister_mode(&xfrm6_transport_mode, AF_INET6);
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BUG_ON(err);
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}
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module_init(xfrm6_transport_init);
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module_exit(xfrm6_transport_exit);
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TRANSPORT);
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