forked from Minki/linux
7b277b1a5f
This patch changes the calling convention so that on entry from x->mode->output and before entry into x->type->output skb->data will point to the payload instead of the IP header. This is essentially a redistribution of skb_push/skb_pull calls with the aim of minimising them on the common path of tunnel + ESP. It'll also let us use the same calling convention between IPv4 and IPv6 with the next patch. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
93 lines
2.7 KiB
C
93 lines
2.7 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 the mac header will be set to the
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* nextheader field of the extension header directly preceding the
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* encapsulation header, or in its absence, that of the top IP header.
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* The value of the network header will always point to the top IP header
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* while skb->data will point to the payload.
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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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iph = ipv6_hdr(skb);
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hdr_len = x->type->hdr_offset(x, skb, &prevhdr);
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skb_set_mac_header(skb, (prevhdr - x->props.header_len) - skb->data);
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skb_set_network_header(skb, -x->props.header_len);
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skb_set_transport_header(skb, hdr_len - x->props.header_len);
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__skb_pull(skb, hdr_len);
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memmove(ipv6_hdr(skb), 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_transport_header(skb);
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if (skb->transport_header != skb->network_header) {
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memmove(skb_transport_header(skb),
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skb_network_header(skb), ihl);
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skb->network_header = skb->transport_header;
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}
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ipv6_hdr(skb)->payload_len = htons(skb->len + ihl -
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sizeof(struct ipv6hdr));
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skb_reset_transport_header(skb);
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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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