140 lines
3.3 KiB
C
140 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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* The following fields in it shall be filled in by x->type->output:
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* tot_len
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* check
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*
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* On exit, skb->h will be set to the start of the payload to be processed
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* by x->type->output and skb->nh will be set to the top IP header.
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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 iphdr *iph, *top_iph = NULL;
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int hdrlen, optlen;
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iph = skb->nh.iph;
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skb->h.ipiph = iph;
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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->nh.raw = skb_push(skb, x->props.header_len + hdrlen);
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top_iph = skb->nh.iph;
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hdrlen = iph->ihl * 4 - optlen;
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skb->h.raw += hdrlen;
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memmove(top_iph, iph, hdrlen);
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if (unlikely(optlen)) {
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struct ip_beet_phdr *ph;
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BUG_ON(optlen < 0);
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ph = (struct ip_beet_phdr *)skb->h.raw;
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ph->padlen = 4 - (optlen & 4);
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ph->hdrlen = (optlen + ph->padlen + sizeof(*ph)) / 8;
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ph->nexthdr = top_iph->protocol;
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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 = skb->nh.iph;
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int phlen = 0;
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int optlen = 0;
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__u8 ph_nexthdr = 0, protocol = 0;
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int err = -EINVAL;
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protocol = iph->protocol;
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if (unlikely(iph->protocol == IPPROTO_BEETPH)) {
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struct ip_beet_phdr *ph = (struct ip_beet_phdr*)(iph + 1);
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if (!pskb_may_pull(skb, sizeof(*ph)))
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goto out;
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phlen = ph->hdrlen * 8;
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optlen = phlen - ph->padlen - sizeof(*ph);
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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))
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goto out;
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ph_nexthdr = ph->nexthdr;
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}
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skb_push(skb, sizeof(*iph) - phlen + optlen);
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memmove(skb->data, skb->nh.raw, sizeof(*iph));
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skb->nh.raw = skb->data;
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iph = skb->nh.iph;
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iph->ihl = (sizeof(*iph) + optlen) / 4;
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iph->tot_len = htons(skb->len);
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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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else
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iph->protocol = protocol;
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iph->check = 0;
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iph->check = ip_fast_csum(skb->nh.raw, 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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