LXR linux/net/ipv6/xfrm6_mode

   1/*
   2 * xfrm6_mode_tunnel.c - Tunnel mode encapsulation for IPv6.
   3 *
   4 * Copyright (C) 2002 USAGI/WIDE Project
   5 * Copyright (c) 2004-2006 Herbert Xu <herbert@gondor.apana.org.au>
   6 */
   7
   8#include <linux/gfp.h>
   9#include <linux/init.h>
  10#include <linux/kernel.h>
  11#include <linux/module.h>
  12#include <linux/skbuff.h>
  13#include <linux/stringify.h>
  14#include <net/dsfield.h>
  15#include <net/dst.h>
  16#include <net/inet_ecn.h>
  17#include <net/ip6_route.h>
  18#include <net/ipv6.h>
  19#include <net/xfrm.h>
  20
  21static inline void ipip6_ecn_decapsulate(struct sk_buff *skb)
  22{
  23        struct ipv6hdr *inner_iph = ipipv6_hdr(skb);
  24
  25        if (INET_ECN_is_ce(XFRM_MODE_SKB_CB(skb)->tos))
  26                IP6_ECN_set_ce(skb, inner_iph);
  27}
  28
  29/* Add encapsulation header.
  30 *
  31 * The top IP header will be constructed per RFC 2401.
  32 */
  33static int xfrm6_mode_tunnel_output(struct xfrm_state *x, struct sk_buff *skb)
  34{
  35        struct dst_entry *dst = skb_dst(skb);
  36        struct ipv6hdr *top_iph;
  37        int dsfield;
  38
  39        skb_set_network_header(skb, -x->props.header_len);
  40        skb->mac_header = skb->network_header +
  41                          offsetof(struct ipv6hdr, nexthdr);
  42        skb->transport_header = skb->network_header + sizeof(*top_iph);
  43        top_iph = ipv6_hdr(skb);
  44
  45        top_iph->version = 6;
  46
  47        memcpy(top_iph->flow_lbl, XFRM_MODE_SKB_CB(skb)->flow_lbl,
  48               sizeof(top_iph->flow_lbl));
  49        top_iph->nexthdr = xfrm_af2proto(skb_dst(skb)->ops->family);
  50
  51        if (x->props.extra_flags & XFRM_SA_XFLAG_DONT_ENCAP_DSCP)
  52                dsfield = 0;
  53        else
  54                dsfield = XFRM_MODE_SKB_CB(skb)->tos;
  55        dsfield = INET_ECN_encapsulate(dsfield, XFRM_MODE_SKB_CB(skb)->tos);
  56        if (x->props.flags & XFRM_STATE_NOECN)
  57                dsfield &= ~INET_ECN_MASK;
  58        ipv6_change_dsfield(top_iph, 0, dsfield);
  59        top_iph->hop_limit = ip6_dst_hoplimit(dst->child);
  60        top_iph->saddr = *(struct in6_addr *)&x->props.saddr;
  61        top_iph->daddr = *(struct in6_addr *)&x->id.daddr;
  62        return 0;
  63}
  64
  65#define for_each_input_rcu(head, handler)       \
  66        for (handler = rcu_dereference(head);   \
  67             handler != NULL;                   \
  68             handler = rcu_dereference(handler->next))
  69
  70
  71static int xfrm6_mode_tunnel_input(struct xfrm_state *x, struct sk_buff *skb)
  72{
  73        int err = -EINVAL;
  74
  75        if (XFRM_MODE_SKB_CB(skb)->protocol != IPPROTO_IPV6)
  76                goto out;
  77        if (!pskb_may_pull(skb, sizeof(struct ipv6hdr)))
  78                goto out;
  79
  80        err = skb_unclone(skb, GFP_ATOMIC);
  81        if (err)
  82                goto out;
  83
  84        if (x->props.flags & XFRM_STATE_DECAP_DSCP)
  85                ipv6_copy_dscp(ipv6_get_dsfield(ipv6_hdr(skb)),
  86                               ipipv6_hdr(skb));
  87        if (!(x->props.flags & XFRM_STATE_NOECN))
  88                ipip6_ecn_decapsulate(skb);
  89
  90        skb_reset_network_header(skb);
  91        skb_mac_header_rebuild(skb);
  92
  93        err = 0;
  94
  95out:
  96        return err;
  97}
  98
  99static struct xfrm_mode xfrm6_tunnel_mode = {
 100        .input2 = xfrm6_mode_tunnel_input,
 101        .input = xfrm_prepare_input,
 102        .output2 = xfrm6_mode_tunnel_output,
 103        .output = xfrm6_prepare_output,
 104        .owner = THIS_MODULE,
 105        .encap = XFRM_MODE_TUNNEL,
 106        .flags = XFRM_MODE_FLAG_TUNNEL,
 107};
 108
 109static int __init xfrm6_mode_tunnel_init(void)
 110{
 111        return xfrm_register_mode(&xfrm6_tunnel_mode, AF_INET6);
 112}
 113
 114static void __exit xfrm6_mode_tunnel_exit(void)
 115{
 116        int err;
 117
 118        err = xfrm_unregister_mode(&xfrm6_tunnel_mode, AF_INET6);
 119        BUG_ON(err);
 120}
 121
 122module_init(xfrm6_mode_tunnel_init);
 123module_exit(xfrm6_mode_tunnel_exit);
 124MODULE_LICENSE("GPL");
 125MODULE_ALIAS_XFRM_MODE(AF_INET6, XFRM_MODE_TUNNEL);
 126