net/ipv6/xfrm6_mode_beet.c

   1 /*
   2  * xfrm6_mode_beet.c - BEET mode encapsulation for IPv6.
   3  *
   4  * Copyright (c) 2006 Diego Beltrami <diego.beltrami@gmail.com>
   5  *                    Miika Komu     <miika@iki.fi>
   6  *                    Herbert Xu     <herbert@gondor.apana.org.au>
   7  *                    Abhinav Pathak <abhinav.pathak@hiit.fi>
   8  *                    Jeff Ahrenholz <ahrenholz@gmail.com>
   9  */
  10
  11 #include <linux/init.h>
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/skbuff.h>
  15 #include <linux/stringify.h>
  16 #include <net/dsfield.h>
  17 #include <net/dst.h>
  18 #include <net/inet_ecn.h>
  19 #include <net/ipv6.h>
  20 #include <net/xfrm.h>
  21
  22 /* Add encapsulation header.
  23  *
  24  * The top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt.
  25  */
  26 static int xfrm6_beet_output(struct xfrm_state *x, struct sk_buff *skb)
  27 {
  28         struct ipv6hdr *iph, *top_iph;
  29         u8 *prevhdr;
  30         int hdr_len;
  31
  32         iph = ipv6_hdr(skb);
  33
  34         hdr_len = ip6_find_1stfragopt(skb, &prevhdr);
  35
  36         skb_set_mac_header(skb, (prevhdr - x->props.header_len) - skb->data);
  37         skb_set_network_header(skb, -x->props.header_len);
  38         skb->transport_header = skb->network_header + hdr_len;
  39         __skb_pull(skb, hdr_len);
  40
  41         top_iph = ipv6_hdr(skb);
  42         memmove(top_iph, iph, hdr_len);
  43
  44         ipv6_addr_copy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr);
  45         ipv6_addr_copy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr);
  46
  47         return 0;
  48 }
  49
  50 static int xfrm6_beet_input(struct xfrm_state *x, struct sk_buff *skb)
  51 {
  52         struct ipv6hdr *ip6h;
  53         const unsigned char *old_mac;
  54         int size = sizeof(struct ipv6hdr);
  55         int err = -EINVAL;
  56
  57         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
  58                 goto out;
  59
  60         skb_push(skb, size);
  61         memmove(skb->data, skb_network_header(skb), size);
  62         skb_reset_network_header(skb);
  63
  64         old_mac = skb_mac_header(skb);
  65         skb_set_mac_header(skb, -skb->mac_len);
  66         memmove(skb_mac_header(skb), old_mac, skb->mac_len);
  67
  68         ip6h = ipv6_hdr(skb);
  69         ip6h->payload_len = htons(skb->len - size);
  70         ipv6_addr_copy(&ip6h->daddr, (struct in6_addr *) &x->sel.daddr.a6);
  71         ipv6_addr_copy(&ip6h->saddr, (struct in6_addr *) &x->sel.saddr.a6);
  72         err = 0;
  73 out:
  74         return err;
  75 }
  76
  77 static struct xfrm_mode xfrm6_beet_mode = {
  78         .input = xfrm6_beet_input,
  79         .output = xfrm6_beet_output,
  80         .owner = THIS_MODULE,
  81         .encap = XFRM_MODE_BEET,
  82         .flags = XFRM_MODE_FLAG_TUNNEL,
  83 };
  84
  85 static int __init xfrm6_beet_init(void)
  86 {
  87         return xfrm_register_mode(&xfrm6_beet_mode, AF_INET6);
  88 }
  89
  90 static void __exit xfrm6_beet_exit(void)
  91 {
  92         int err;
  93
  94         err = xfrm_unregister_mode(&xfrm6_beet_mode, AF_INET6);
  95         BUG_ON(err);
  96 }
  97
  98 module_init(xfrm6_beet_init);
  99 module_exit(xfrm6_beet_exit);
 100 MODULE_LICENSE("GPL");
 101 MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_BEET);