/* iptables module for using new netfilter netlink queue
   *
   * (C) 2005 by Harald Welte <laforge@netfilter.org>
   *
   * This program is free software; you can redistribute it and/or modify

   * it under the terms of the GNU General Public License version 2 as

   * published by the Free Software Foundation.

   *

   */
  
  #include <linux/module.h>
  #include <linux/skbuff.h>

  #include <linux/ip.h>
  #include <linux/ipv6.h>
  #include <linux/jhash.h>

  #include <linux/netfilter.h>
  #include <linux/netfilter_arp.h>
  #include <linux/netfilter/x_tables.h>
  #include <linux/netfilter/xt_NFQUEUE.h>
  
  MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");

  MODULE_DESCRIPTION("Xtables: packet forwarding to netlink");

  MODULE_LICENSE("GPL");
  MODULE_ALIAS("ipt_NFQUEUE");
  MODULE_ALIAS("ip6t_NFQUEUE");
  MODULE_ALIAS("arpt_NFQUEUE");

  static u32 jhash_initval __read_mostly;

  static unsigned int

  nfqueue_tg(struct sk_buff *skb, const struct xt_target_param *par)

  {

  	const struct xt_NFQ_info *tinfo = par->targinfo;

  
  	return NF_QUEUE_NR(tinfo->queuenum);
  }

  static u32 hash_v4(const struct sk_buff *skb)
  {
  	const struct iphdr *iph = ip_hdr(skb);

  	__be32 ipaddr;

  
  	/* packets in either direction go into same queue */
  	ipaddr = iph->saddr ^ iph->daddr;

  	return jhash_2words((__force u32)ipaddr, iph->protocol, jhash_initval);

  }
  
  static unsigned int
  nfqueue_tg4_v1(struct sk_buff *skb, const struct xt_target_param *par)
  {
  	const struct xt_NFQ_info_v1 *info = par->targinfo;
  	u32 queue = info->queuenum;
  
  	if (info->queues_total > 1)
  		queue = hash_v4(skb) % info->queues_total + queue;
  	return NF_QUEUE_NR(queue);
  }
  
  #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
  static u32 hash_v6(const struct sk_buff *skb)
  {
  	const struct ipv6hdr *ip6h = ipv6_hdr(skb);

  	__be32 addr[4];

  
  	addr[0] = ip6h->saddr.s6_addr32[0] ^ ip6h->daddr.s6_addr32[0];
  	addr[1] = ip6h->saddr.s6_addr32[1] ^ ip6h->daddr.s6_addr32[1];
  	addr[2] = ip6h->saddr.s6_addr32[2] ^ ip6h->daddr.s6_addr32[2];
  	addr[3] = ip6h->saddr.s6_addr32[3] ^ ip6h->daddr.s6_addr32[3];

  	return jhash2((__force u32 *)addr, ARRAY_SIZE(addr), jhash_initval);

  }
  
  static unsigned int
  nfqueue_tg6_v1(struct sk_buff *skb, const struct xt_target_param *par)
  {
  	const struct xt_NFQ_info_v1 *info = par->targinfo;
  	u32 queue = info->queuenum;
  
  	if (info->queues_total > 1)
  		queue = hash_v6(skb) % info->queues_total + queue;
  	return NF_QUEUE_NR(queue);
  }
  #endif
  
  static bool nfqueue_tg_v1_check(const struct xt_tgchk_param *par)
  {
  	const struct xt_NFQ_info_v1 *info = par->targinfo;
  	u32 maxid;
  
  	if (info->queues_total == 0) {
  		pr_err("NFQUEUE: number of total queues is 0
  ");
  		return false;
  	}
  	maxid = info->queues_total - 1 + info->queuenum;
  	if (maxid > 0xffff) {
  		pr_err("NFQUEUE: number of queues (%u) out of range (got %u)
  ",
  		       info->queues_total, maxid);
  		return false;
  	}
  	return true;
  }

  static struct xt_target nfqueue_tg_reg[] __read_mostly = {

  	{
  		.name		= "NFQUEUE",

  		.family		= NFPROTO_UNSPEC,

  		.target		= nfqueue_tg,

  		.targetsize	= sizeof(struct xt_NFQ_info),
  		.me		= THIS_MODULE,
  	},

  	{
  		.name		= "NFQUEUE",
  		.revision	= 1,
  		.family		= NFPROTO_IPV4,
  		.checkentry	= nfqueue_tg_v1_check,
  		.target		= nfqueue_tg4_v1,
  		.targetsize	= sizeof(struct xt_NFQ_info_v1),
  		.me		= THIS_MODULE,
  	},
  #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
  	{
  		.name		= "NFQUEUE",
  		.revision	= 1,
  		.family		= NFPROTO_IPV6,
  		.checkentry	= nfqueue_tg_v1_check,
  		.target		= nfqueue_tg6_v1,
  		.targetsize	= sizeof(struct xt_NFQ_info_v1),
  		.me		= THIS_MODULE,
  	},
  #endif

  };

  static int __init nfqueue_tg_init(void)

  {

  	get_random_bytes(&jhash_initval, sizeof(jhash_initval));

  	return xt_register_targets(nfqueue_tg_reg, ARRAY_SIZE(nfqueue_tg_reg));

  }

  static void __exit nfqueue_tg_exit(void)

  {

  	xt_unregister_targets(nfqueue_tg_reg, ARRAY_SIZE(nfqueue_tg_reg));

  }

  module_init(nfqueue_tg_init);
  module_exit(nfqueue_tg_exit);