138 lines
3.5 KiB
C
138 lines
3.5 KiB
C
/*
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* xfrm6_mode_beet.c - BEET mode encapsulation for IPv6.
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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/dsfield.h>
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#include <net/dst.h>
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#include <net/inet_ecn.h>
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#include <net/ipv6.h>
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#include <net/xfrm.h>
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static void xfrm6_beet_make_header(struct sk_buff *skb)
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{
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struct ipv6hdr *iph = ipv6_hdr(skb);
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iph->version = 6;
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memcpy(iph->flow_lbl, XFRM_MODE_SKB_CB(skb)->flow_lbl,
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sizeof(iph->flow_lbl));
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iph->nexthdr = XFRM_MODE_SKB_CB(skb)->protocol;
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ipv6_change_dsfield(iph, 0, XFRM_MODE_SKB_CB(skb)->tos);
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iph->hop_limit = 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 xfrm6_beet_output(struct xfrm_state *x, struct sk_buff *skb)
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{
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struct ipv6hdr *top_iph;
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struct ip_beet_phdr *ph;
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struct iphdr *iphv4;
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int optlen, hdr_len;
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iphv4 = ip_hdr(skb);
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hdr_len = 0;
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optlen = XFRM_MODE_SKB_CB(skb)->optlen;
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if (unlikely(optlen))
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hdr_len += IPV4_BEET_PHMAXLEN - (optlen & 4);
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skb_set_network_header(skb, -x->props.header_len - hdr_len);
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if (x->sel.family != AF_INET6)
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skb->network_header += IPV4_BEET_PHMAXLEN;
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skb->mac_header = skb->network_header +
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offsetof(struct ipv6hdr, nexthdr);
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skb->transport_header = skb->network_header + sizeof(*top_iph);
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ph = (struct ip_beet_phdr *)__skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl-hdr_len);
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xfrm6_beet_make_header(skb);
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top_iph = ipv6_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->nexthdr;
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if (ph->padlen)
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memset(ph + 1, IPOPT_NOP, ph->padlen);
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top_iph->nexthdr = IPPROTO_BEETPH;
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}
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ipv6_addr_copy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr);
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ipv6_addr_copy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr);
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return 0;
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}
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static int xfrm6_beet_input(struct xfrm_state *x, struct sk_buff *skb)
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{
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struct ipv6hdr *ip6h;
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const unsigned char *old_mac;
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int size = sizeof(struct ipv6hdr);
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int err;
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err = skb_cow_head(skb, size + skb->mac_len);
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if (err)
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goto out;
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__skb_push(skb, size);
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skb_reset_network_header(skb);
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old_mac = skb_mac_header(skb);
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skb_set_mac_header(skb, -skb->mac_len);
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memmove(skb_mac_header(skb), old_mac, skb->mac_len);
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xfrm6_beet_make_header(skb);
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ip6h = ipv6_hdr(skb);
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ip6h->payload_len = htons(skb->len - size);
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ipv6_addr_copy(&ip6h->daddr, (struct in6_addr *) &x->sel.daddr.a6);
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ipv6_addr_copy(&ip6h->saddr, (struct in6_addr *) &x->sel.saddr.a6);
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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 xfrm6_beet_mode = {
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.input2 = xfrm6_beet_input,
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.input = xfrm_prepare_input,
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.output2 = xfrm6_beet_output,
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.output = xfrm6_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 xfrm6_beet_init(void)
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{
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return xfrm_register_mode(&xfrm6_beet_mode, AF_INET6);
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}
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static void __exit xfrm6_beet_exit(void)
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{
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int err;
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err = xfrm_unregister_mode(&xfrm6_beet_mode, AF_INET6);
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BUG_ON(err);
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}
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module_init(xfrm6_beet_init);
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module_exit(xfrm6_beet_exit);
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MODULE_LICENSE("GPL");
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MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_BEET);
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