05d224468a
draft-nikander-esp-beet-mode-07.txt is not entirely clear on how the length value of the pseudo header should be calculated, it states "The Header Length field contains the length of the pseudo header, IPv4 options, and padding in 8 octets units.", but also states "Length in octets (Header Len + 1) * 8". draft-nikander-esp-beet-mode-08-pre1.txt [1] clarifies this, the header length should not include the first 8 byte. This change affects backwards compatibility, but option encapsulation didn't work until very recently anyway. [1] http://users.piuha.net/jmelen/BEET/draft-nikander-esp-beet-mode-08-pre1.txt Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>
143 lines
3.5 KiB
C
143 lines
3.5 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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skb->h.raw += sizeof(*iph) - hdrlen;
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memmove(top_iph, iph, sizeof(*iph));
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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 / 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 = 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;
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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 *)(skb->h.ipiph + 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->nh.raw = skb->data + (phlen - sizeof(*iph));
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memmove(skb->nh.raw, iph, sizeof(*iph));
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skb->h.raw = skb->data + (phlen + optlen);
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skb->data = skb->h.raw;
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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 + 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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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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