forked from Minki/linux
31a4ab9302
Now that we have xfrm_mode objects we can move the transport mode specific input decapsulation code into xfrm_mode_transport. This removes duplicate code as well as unnecessary header movement in case of tunnel mode SAs since we will discard the original IP header immediately. This also fixes a minor bug for transport-mode ESP where the IP payload length is set to the correct value minus the header length (with extension headers for IPv6). Of course the other neat thing is that we no longer have to allocate temporary buffers to hold the IP headers for ESP and IPComp. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
89 lines
2.4 KiB
C
89 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 sk_buff *skb)
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{
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struct xfrm_state *x = skb->dst->xfrm;
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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 = ip6_find_1stfragopt(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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