net/ipv6/netfilter.c

   1 #include <linux/config.h>
   2 #include <linux/init.h>
   3
   4 #ifdef CONFIG_NETFILTER
   5
   6 #include <linux/kernel.h>
   7 #include <linux/ipv6.h>
   8 #include <linux/netfilter.h>
   9 #include <linux/netfilter_ipv6.h>
  10 #include <net/dst.h>
  11 #include <net/ipv6.h>
  12 #include <net/ip6_route.h>
  13 #include <net/xfrm.h>
  14
  15 int ip6_route_me_harder(struct sk_buff *skb)
  16 {
  17         struct ipv6hdr *iph = skb->nh.ipv6h;
  18         struct dst_entry *dst;
  19         struct flowi fl = {
  20                 .oif = skb->sk ? skb->sk->sk_bound_dev_if : 0,
  21                 .nl_u =
  22                 { .ip6_u =
  23                   { .daddr = iph->daddr,
  24                     .saddr = iph->saddr, } },
  25         };
  26
  27         dst = ip6_route_output(skb->sk, &fl);
  28
  29 #ifdef CONFIG_XFRM
  30         if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) &&
  31             xfrm_decode_session(skb, &fl, AF_INET6) == 0)
  32                 if (xfrm_lookup(&skb->dst, &fl, skb->sk, 0))
  33                         return -1;
  34 #endif
  35
  36         if (dst->error) {
  37                 IP6_INC_STATS(IPSTATS_MIB_OUTNOROUTES);
  38                 LIMIT_NETDEBUG(KERN_DEBUG "ip6_route_me_harder: No more route.\n");
  39                 dst_release(dst);
  40                 return -EINVAL;
  41         }
  42
  43         /* Drop old route. */
  44         dst_release(skb->dst);
  45
  46         skb->dst = dst;
  47         return 0;
  48 }
  49 EXPORT_SYMBOL(ip6_route_me_harder);
  50
  51 /*
  52  * Extra routing may needed on local out, as the QUEUE target never
  53  * returns control to the table.
  54  */
  55
  56 struct ip6_rt_info {
  57         struct in6_addr daddr;
  58         struct in6_addr saddr;
  59 };
  60
  61 static void save(const struct sk_buff *skb, struct nf_info *info)
  62 {
  63         struct ip6_rt_info *rt_info = nf_info_reroute(info);
  64
  65         if (info->hook == NF_IP6_LOCAL_OUT) {
  66                 struct ipv6hdr *iph = skb->nh.ipv6h;
  67
  68                 rt_info->daddr = iph->daddr;
  69                 rt_info->saddr = iph->saddr;
  70         }
  71 }
  72
  73 static int reroute(struct sk_buff **pskb, const struct nf_info *info)
  74 {
  75         struct ip6_rt_info *rt_info = nf_info_reroute(info);
  76
  77         if (info->hook == NF_IP6_LOCAL_OUT) {
  78                 struct ipv6hdr *iph = (*pskb)->nh.ipv6h;
  79                 if (!ipv6_addr_equal(&iph->daddr, &rt_info->daddr) ||
  80                     !ipv6_addr_equal(&iph->saddr, &rt_info->saddr))
  81                         return ip6_route_me_harder(*pskb);
  82         }
  83         return 0;
  84 }
  85
  86 static struct nf_queue_rerouter ip6_reroute = {
  87         .rer_size       = sizeof(struct ip6_rt_info),
  88         .save           = &save,
  89         .reroute        = &reroute,
  90 };
  91
  92 int __init ipv6_netfilter_init(void)
  93 {
  94         return nf_register_queue_rerouter(PF_INET6, &ip6_reroute);
  95 }
  96
  97 void ipv6_netfilter_fini(void)
  98 {
  99         nf_unregister_queue_rerouter(PF_INET6);
 100 }
 101
 102 #else /* CONFIG_NETFILTER */
 103 int __init ipv6_netfilter_init(void)
 104 {
 105         return 0;
 106 }
 107
 108 void ipv6_netfilter_fini(void)
 109 {
 110 }
 111 #endif /* CONFIG_NETFILTER */