158 lines
3.7 KiB
C
158 lines
3.7 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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static void xfrm4_beet_make_header(struct sk_buff *skb)
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{
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struct iphdr *iph = ip_hdr(skb);
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iph->ihl = 5;
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iph->version = 4;
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iph->protocol = XFRM_MODE_SKB_CB(skb)->protocol;
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iph->tos = XFRM_MODE_SKB_CB(skb)->tos;
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iph->id = XFRM_MODE_SKB_CB(skb)->id;
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iph->frag_off = XFRM_MODE_SKB_CB(skb)->frag_off;
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iph->ttl = XFRM_MODE_SKB_CB(skb)->ttl;
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}
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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 *top_iph;
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int hdrlen, optlen;
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hdrlen = 0;
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optlen = XFRM_MODE_SKB_CB(skb)->optlen;
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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(*top_iph);
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xfrm4_beet_make_header(skb);
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ph = (struct ip_beet_phdr *)
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__skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl - hdrlen);
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top_iph = ip_hdr(skb);
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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;
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int optlen = 0;
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int err = -EINVAL;
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if (unlikely(XFRM_MODE_SKB_CB(skb)->protocol == IPPROTO_BEETPH)) {
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struct ip_beet_phdr *ph;
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int phlen;
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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->data;
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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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XFRM_MODE_SKB_CB(skb)->protocol = ph->nexthdr;
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if (!pskb_may_pull(skb, phlen))
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goto out;
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__skb_pull(skb, phlen);
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}
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skb_push(skb, sizeof(*iph));
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skb_reset_network_header(skb);
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memmove(skb->data - skb->mac_len, skb_mac_header(skb),
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skb->mac_len);
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skb_set_mac_header(skb, -skb->mac_len);
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xfrm4_beet_make_header(skb);
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iph = ip_hdr(skb);
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iph->ihl += 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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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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.input2 = xfrm4_beet_input,
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.input = xfrm_prepare_input,
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.output2 = xfrm4_beet_output,
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.output = xfrm4_prepare_output,
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.owner = THIS_MODULE,
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.encap = XFRM_MODE_BEET,
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.flags = XFRM_MODE_FLAG_TUNNEL,
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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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