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  * The following fields in it shall be filled in by x->type->output:
  26  *      payload_len
  27  */
  28 static int xfrm6_beet_output(struct xfrm_state *x, struct sk_buff *skb)
  29 {
  30         struct ipv6hdr *iph, *top_iph;
  31         u8 *prevhdr;
  32         int hdr_len;
  33
  34         iph = ipv6_hdr(skb);
  35
  36         hdr_len = ip6_find_1stfragopt(skb, &prevhdr);
  37
  38         skb_set_mac_header(skb, (prevhdr - x->props.header_len) - skb->data);
  39         skb_set_network_header(skb, -x->props.header_len);
  40         skb->transport_header = skb->network_header + hdr_len;
  41         __skb_pull(skb, hdr_len);
  42
  43         top_iph = ipv6_hdr(skb);
  44         memmove(top_iph, iph, hdr_len);
  45
  46         ipv6_addr_copy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr);
  47         ipv6_addr_copy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr);
  48
  49         return 0;
  50 }
  51
  52 static int xfrm6_beet_input(struct xfrm_state *x, struct sk_buff *skb)
  53 {
  54         struct ipv6hdr *ip6h;
  55         const unsigned char *old_mac;
  56         int size = sizeof(struct ipv6hdr);
  57         int err = -EINVAL;
  58
  59         if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
  60                 goto out;
  61
  62         skb_push(skb, size);
  63         memmove(skb->data, skb_network_header(skb), size);
  64         skb_reset_network_header(skb);
  65
  66         old_mac = skb_mac_header(skb);
  67         skb_set_mac_header(skb, -skb->mac_len);
  68         memmove(skb_mac_header(skb), old_mac, skb->mac_len);
  69
  70         ip6h = ipv6_hdr(skb);
  71         ip6h->payload_len = htons(skb->len - size);
  72         ipv6_addr_copy(&ip6h->daddr, (struct in6_addr *) &x->sel.daddr.a6);
  73         ipv6_addr_copy(&ip6h->saddr, (struct in6_addr *) &x->sel.saddr.a6);
  74         err = 0;
  75 out:
  76         return err;
  77 }
  78
  79 static struct xfrm_mode xfrm6_beet_mode = {
  80         .input = xfrm6_beet_input,
  81         .output = xfrm6_beet_output,
  82         .owner = THIS_MODULE,
  83         .encap = XFRM_MODE_BEET,
  84 };
  85
  86 static int __init xfrm6_beet_init(void)
  87 {
  88         return xfrm_register_mode(&xfrm6_beet_mode, AF_INET6);
  89 }
  90
  91 static void __exit xfrm6_beet_exit(void)
  92 {
  93         int err;
  94
  95         err = xfrm_unregister_mode(&xfrm6_beet_mode, AF_INET6);
  96         BUG_ON(err);
  97 }
  98
  99 module_init(xfrm6_beet_init);
 100 module_exit(xfrm6_beet_exit);
 101 MODULE_LICENSE("GPL");
 102 MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_BEET);