net/ipv6/netfilter.c

   1 #include <linux/kernel.h>
   2 #include <linux/init.h>
   3 #include <linux/ipv6.h>
   4 #include <linux/netfilter.h>
   5 #include <linux/netfilter_ipv6.h>
   6 #include <net/dst.h>
   7 #include <net/ipv6.h>
   8 #include <net/ip6_route.h>
   9 #include <net/xfrm.h>
  10
  11 int ip6_route_me_harder(struct sk_buff *skb)
  12 {
  13         struct ipv6hdr *iph = skb->nh.ipv6h;
  14         struct dst_entry *dst;
  15         struct flowi fl = {
  16                 .oif = skb->sk ? skb->sk->sk_bound_dev_if : 0,
  17                 .nl_u =
  18                 { .ip6_u =
  19                   { .daddr = iph->daddr,
  20                     .saddr = iph->saddr, } },
  21         };
  22
  23         dst = ip6_route_output(skb->sk, &fl);
  24
  25 #ifdef CONFIG_XFRM
  26         if (!(IP6CB(skb)->flags & IP6SKB_XFRM_TRANSFORMED) &&
  27             xfrm_decode_session(skb, &fl, AF_INET6) == 0)
  28                 if (xfrm_lookup(&skb->dst, &fl, skb->sk, 0))
  29                         return -1;
  30 #endif
  31
  32         if (dst->error) {
  33                 IP6_INC_STATS(IPSTATS_MIB_OUTNOROUTES);
  34                 LIMIT_NETDEBUG(KERN_DEBUG "ip6_route_me_harder: No more route.\n");
  35                 dst_release(dst);
  36                 return -EINVAL;
  37         }
  38
  39         /* Drop old route. */
  40         dst_release(skb->dst);
  41
  42         skb->dst = dst;
  43         return 0;
  44 }
  45 EXPORT_SYMBOL(ip6_route_me_harder);
  46
  47 /*
  48  * Extra routing may needed on local out, as the QUEUE target never
  49  * returns control to the table.
  50  */
  51
  52 struct ip6_rt_info {
  53         struct in6_addr daddr;
  54         struct in6_addr saddr;
  55 };
  56
  57 static void save(const struct sk_buff *skb, struct nf_info *info)
  58 {
  59         struct ip6_rt_info *rt_info = nf_info_reroute(info);
  60
  61         if (info->hook == NF_IP6_LOCAL_OUT) {
  62                 struct ipv6hdr *iph = skb->nh.ipv6h;
  63
  64                 rt_info->daddr = iph->daddr;
  65                 rt_info->saddr = iph->saddr;
  66         }
  67 }
  68
  69 static int reroute(struct sk_buff **pskb, const struct nf_info *info)
  70 {
  71         struct ip6_rt_info *rt_info = nf_info_reroute(info);
  72
  73         if (info->hook == NF_IP6_LOCAL_OUT) {
  74                 struct ipv6hdr *iph = (*pskb)->nh.ipv6h;
  75                 if (!ipv6_addr_equal(&iph->daddr, &rt_info->daddr) ||
  76                     !ipv6_addr_equal(&iph->saddr, &rt_info->saddr))
  77                         return ip6_route_me_harder(*pskb);
  78         }
  79         return 0;
  80 }
  81
  82 static struct nf_queue_rerouter ip6_reroute = {
  83         .rer_size       = sizeof(struct ip6_rt_info),
  84         .save           = &save,
  85         .reroute        = &reroute,
  86 };
  87
  88 int __init ipv6_netfilter_init(void)
  89 {
  90         return nf_register_queue_rerouter(PF_INET6, &ip6_reroute);
  91 }
  92
  93 /* This can be called from inet6_init() on errors, so it cannot
  94  * be marked __exit. -DaveM
  95  */
  96 void ipv6_netfilter_fini(void)
  97 {
  98         nf_unregister_queue_rerouter(PF_INET6);
  99 }