ceb1eec829
This patch moves the setting of the IP length and checksum fields out of the transforms and into the xfrmX_output functions. This would help future efforts in merging the transforms themselves. It also adds an optimisation to ipcomp due to the fact that the transport offset is guaranteed to be zero. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
136 lines
3.3 KiB
C
136 lines
3.3 KiB
C
/*
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* xfrm4_mode_beet.c - BEET mode encapsulation for IPv4.
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*
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* Copyright (c) 2006 Diego Beltrami <diego.beltrami@gmail.com>
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* Miika Komu <miika@iki.fi>
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* Herbert Xu <herbert@gondor.apana.org.au>
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* Abhinav Pathak <abhinav.pathak@hiit.fi>
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* Jeff Ahrenholz <ahrenholz@gmail.com>
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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/ip.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 top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt.
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*/
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static int xfrm4_beet_output(struct xfrm_state *x, struct sk_buff *skb)
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{
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struct ip_beet_phdr *ph;
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struct iphdr *iph, *top_iph;
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int hdrlen, optlen;
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iph = ip_hdr(skb);
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hdrlen = 0;
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optlen = iph->ihl * 4 - sizeof(*iph);
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if (unlikely(optlen))
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hdrlen += IPV4_BEET_PHMAXLEN - (optlen & 4);
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skb_set_network_header(skb, IPV4_BEET_PHMAXLEN - x->props.header_len -
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hdrlen);
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skb->mac_header = skb->network_header +
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offsetof(struct iphdr, protocol);
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skb->transport_header = skb->network_header + sizeof(*iph);
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ph = (struct ip_beet_phdr *)__skb_pull(skb, sizeof(*iph) - hdrlen);
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top_iph = ip_hdr(skb);
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memmove(top_iph, iph, sizeof(*iph));
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if (unlikely(optlen)) {
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BUG_ON(optlen < 0);
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ph->padlen = 4 - (optlen & 4);
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ph->hdrlen = optlen / 8;
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ph->nexthdr = top_iph->protocol;
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if (ph->padlen)
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memset(ph + 1, IPOPT_NOP, ph->padlen);
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top_iph->protocol = IPPROTO_BEETPH;
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top_iph->ihl = sizeof(struct iphdr) / 4;
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}
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top_iph->saddr = x->props.saddr.a4;
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top_iph->daddr = x->id.daddr.a4;
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return 0;
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}
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static int xfrm4_beet_input(struct xfrm_state *x, struct sk_buff *skb)
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{
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struct iphdr *iph = ip_hdr(skb);
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int phlen = 0;
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int optlen = 0;
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u8 ph_nexthdr = 0;
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int err = -EINVAL;
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if (unlikely(iph->protocol == IPPROTO_BEETPH)) {
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struct ip_beet_phdr *ph;
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if (!pskb_may_pull(skb, sizeof(*ph)))
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goto out;
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ph = (struct ip_beet_phdr *)(ipip_hdr(skb) + 1);
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phlen = sizeof(*ph) + ph->padlen;
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optlen = ph->hdrlen * 8 + (IPV4_BEET_PHMAXLEN - phlen);
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if (optlen < 0 || optlen & 3 || optlen > 250)
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goto out;
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if (!pskb_may_pull(skb, phlen + optlen))
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goto out;
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skb->len -= phlen + optlen;
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ph_nexthdr = ph->nexthdr;
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}
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skb_set_network_header(skb, phlen - sizeof(*iph));
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memmove(skb_network_header(skb), iph, sizeof(*iph));
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skb_set_transport_header(skb, phlen + optlen);
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skb->data = skb_transport_header(skb);
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iph = ip_hdr(skb);
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iph->ihl = (sizeof(*iph) + optlen) / 4;
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iph->tot_len = htons(skb->len + iph->ihl * 4);
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iph->daddr = x->sel.daddr.a4;
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iph->saddr = x->sel.saddr.a4;
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if (ph_nexthdr)
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iph->protocol = ph_nexthdr;
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iph->check = 0;
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iph->check = ip_fast_csum(skb_network_header(skb), iph->ihl);
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err = 0;
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out:
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return err;
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}
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static struct xfrm_mode xfrm4_beet_mode = {
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.input = xfrm4_beet_input,
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.output = xfrm4_beet_output,
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.owner = THIS_MODULE,
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.encap = XFRM_MODE_BEET,
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};
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static int __init xfrm4_beet_init(void)
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{
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return xfrm_register_mode(&xfrm4_beet_mode, AF_INET);
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}
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static void __exit xfrm4_beet_exit(void)
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{
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int err;
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err = xfrm_unregister_mode(&xfrm4_beet_mode, AF_INET);
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BUG_ON(err);
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}
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module_init(xfrm4_beet_init);
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module_exit(xfrm4_beet_exit);
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_XFRM_MODE(AF_INET, XFRM_MODE_BEET);
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