LXR linux/net/ipv6/xfrm6_mode

   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
  22static void xfrm6_beet_make_header(struct sk_buff *skb)
  23{
  24        struct ipv6hdr *iph = ipv6_hdr(skb);
  25
  26        iph->version = 6;
  27
  28        memcpy(iph->flow_lbl, XFRM_MODE_SKB_CB(skb)->flow_lbl,
  29               sizeof(iph->flow_lbl));
  30        iph->nexthdr = XFRM_MODE_SKB_CB(skb)->protocol;
  31
  32        ipv6_change_dsfield(iph, 0, XFRM_MODE_SKB_CB(skb)->tos);
  33        iph->hop_limit = XFRM_MODE_SKB_CB(skb)->ttl;
  34}
  35
  36/* Add encapsulation header.
  37 *
  38 * The top IP header will be constructed per draft-nikander-esp-beet-mode-06.txt.
  39 */
  40static int xfrm6_beet_output(struct xfrm_state *x, struct sk_buff *skb)
  41{
  42        struct ipv6hdr *top_iph;
  43        struct ip_beet_phdr *ph;
  44        struct iphdr *iphv4;
  45        int optlen, hdr_len;
  46
  47        iphv4 = ip_hdr(skb);
  48        hdr_len = 0;
  49        optlen = XFRM_MODE_SKB_CB(skb)->optlen;
  50        if (unlikely(optlen))
  51                hdr_len += IPV4_BEET_PHMAXLEN - (optlen & 4);
  52
  53        skb_set_network_header(skb, -x->props.header_len - hdr_len);
  54        if (x->sel.family != AF_INET6)
  55                skb->network_header += IPV4_BEET_PHMAXLEN;
  56        skb->mac_header = skb->network_header +
  57                          offsetof(struct ipv6hdr, nexthdr);
  58        skb->transport_header = skb->network_header + sizeof(*top_iph);
  59        ph = (struct ip_beet_phdr *)__skb_pull(skb, XFRM_MODE_SKB_CB(skb)->ihl-hdr_len);
  60
  61        xfrm6_beet_make_header(skb);
  62
  63        top_iph = ipv6_hdr(skb);
  64        if (unlikely(optlen)) {
  65
  66                BUG_ON(optlen < 0);
  67
  68                ph->padlen = 4 - (optlen & 4);
  69                ph->hdrlen = optlen / 8;
  70                ph->nexthdr = top_iph->nexthdr;
  71                if (ph->padlen)
  72                        memset(ph + 1, IPOPT_NOP, ph->padlen);
  73
  74                top_iph->nexthdr = IPPROTO_BEETPH;
  75        }
  76
  77        ipv6_addr_copy(&top_iph->saddr, (struct in6_addr *)&x->props.saddr);
  78        ipv6_addr_copy(&top_iph->daddr, (struct in6_addr *)&x->id.daddr);
  79        return 0;
  80}
  81
  82static int xfrm6_beet_input(struct xfrm_state *x, struct sk_buff *skb)
  83{
  84        struct ipv6hdr *ip6h;
  85        const unsigned char *old_mac;
  86        int size = sizeof(struct ipv6hdr);
  87        int err;
  88
  89        err = skb_cow_head(skb, size + skb->mac_len);
  90        if (err)
  91                goto out;
  92
  93        __skb_push(skb, size);
  94        skb_reset_network_header(skb);
  95
  96        old_mac = skb_mac_header(skb);
  97        skb_set_mac_header(skb, -skb->mac_len);
  98        memmove(skb_mac_header(skb), old_mac, skb->mac_len);
  99
 100        xfrm6_beet_make_header(skb);
 101
 102        ip6h = ipv6_hdr(skb);
 103        ip6h->payload_len = htons(skb->len - size);
 104        ipv6_addr_copy(&ip6h->daddr, (struct in6_addr *) &x->sel.daddr.a6);
 105        ipv6_addr_copy(&ip6h->saddr, (struct in6_addr *) &x->sel.saddr.a6);
 106        err = 0;
 107out:
 108        return err;
 109}
 110
 111static struct xfrm_mode xfrm6_beet_mode = {
 112        .input2 = xfrm6_beet_input,
 113        .input = xfrm_prepare_input,
 114        .output2 = xfrm6_beet_output,
 115        .output = xfrm6_prepare_output,
 116        .owner = THIS_MODULE,
 117        .encap = XFRM_MODE_BEET,
 118        .flags = XFRM_MODE_FLAG_TUNNEL,
 119};
 120
 121static int __init xfrm6_beet_init(void)
 122{
 123        return xfrm_register_mode(&xfrm6_beet_mode, AF_INET6);
 124}
 125
 126static void __exit xfrm6_beet_exit(void)
 127{
 128        int err;
 129
 130        err = xfrm_unregister_mode(&xfrm6_beet_mode, AF_INET6);
 131        BUG_ON(err);
 132}
 133
 134module_init(xfrm6_beet_init);
 135module_exit(xfrm6_beet_exit);
 136MODULE_LICENSE("GPL");
 137MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_BEET);
 138