net/netfilter/xt_NFQUEUE.c

   1 /* iptables module for using new netfilter netlink queue
   2  *
   3  * (C) 2005 by Harald Welte <laforge@netfilter.org>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  */
  10
  11 #include <linux/module.h>
  12 #include <linux/skbuff.h>
  13
  14 #include <linux/ip.h>
  15 #include <linux/ipv6.h>
  16 #include <linux/jhash.h>
  17
  18 #include <linux/netfilter.h>
  19 #include <linux/netfilter_arp.h>
  20 #include <linux/netfilter/x_tables.h>
  21 #include <linux/netfilter/xt_NFQUEUE.h>
  22
  23 MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
  24 MODULE_DESCRIPTION("Xtables: packet forwarding to netlink");
  25 MODULE_LICENSE("GPL");
  26 MODULE_ALIAS("ipt_NFQUEUE");
  27 MODULE_ALIAS("ip6t_NFQUEUE");
  28 MODULE_ALIAS("arpt_NFQUEUE");
  29
  30 static u32 jhash_initval __read_mostly;
  31 static bool rnd_inited __read_mostly;
  32
  33 static unsigned int
  34 nfqueue_tg(struct sk_buff *skb, const struct xt_action_param *par)
  35 {
  36         const struct xt_NFQ_info *tinfo = par->targinfo;
  37
  38         return NF_QUEUE_NR(tinfo->queuenum);
  39 }
  40
  41 static u32 hash_v4(const struct sk_buff *skb)
  42 {
  43         const struct iphdr *iph = ip_hdr(skb);
  44         __be32 ipaddr;
  45
  46         /* packets in either direction go into same queue */
  47         ipaddr = iph->saddr ^ iph->daddr;
  48
  49         return jhash_2words((__force u32)ipaddr, iph->protocol, jhash_initval);
  50 }
  51
  52 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
  53 static u32 hash_v6(const struct sk_buff *skb)
  54 {
  55         const struct ipv6hdr *ip6h = ipv6_hdr(skb);
  56         __be32 addr[4];
  57
  58         addr[0] = ip6h->saddr.s6_addr32[0] ^ ip6h->daddr.s6_addr32[0];
  59         addr[1] = ip6h->saddr.s6_addr32[1] ^ ip6h->daddr.s6_addr32[1];
  60         addr[2] = ip6h->saddr.s6_addr32[2] ^ ip6h->daddr.s6_addr32[2];
  61         addr[3] = ip6h->saddr.s6_addr32[3] ^ ip6h->daddr.s6_addr32[3];
  62
  63         return jhash2((__force u32 *)addr, ARRAY_SIZE(addr), jhash_initval);
  64 }
  65 #endif
  66
  67 static unsigned int
  68 nfqueue_tg_v1(struct sk_buff *skb, const struct xt_action_param *par)
  69 {
  70         const struct xt_NFQ_info_v1 *info = par->targinfo;
  71         u32 queue = info->queuenum;
  72
  73         if (info->queues_total > 1) {
  74                 if (par->family == NFPROTO_IPV4)
  75                         queue = hash_v4(skb) % info->queues_total + queue;
  76 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
  77                 else if (par->family == NFPROTO_IPV6)
  78                         queue = hash_v6(skb) % info->queues_total + queue;
  79 #endif
  80         }
  81         return NF_QUEUE_NR(queue);
  82 }
  83
  84 static int nfqueue_tg_v1_check(const struct xt_tgchk_param *par)
  85 {
  86         const struct xt_NFQ_info_v1 *info = par->targinfo;
  87         u32 maxid;
  88
  89         if (unlikely(!rnd_inited)) {
  90                 get_random_bytes(&jhash_initval, sizeof(jhash_initval));
  91                 rnd_inited = true;
  92         }
  93         if (info->queues_total == 0) {
  94                 pr_err("NFQUEUE: number of total queues is 0\n");
  95                 return -EINVAL;
  96         }
  97         maxid = info->queues_total - 1 + info->queuenum;
  98         if (maxid > 0xffff) {
  99                 pr_err("NFQUEUE: number of queues (%u) out of range (got %u)\n",
 100                        info->queues_total, maxid);
 101                 return -ERANGE;
 102         }
 103         return 0;
 104 }
 105
 106 static struct xt_target nfqueue_tg_reg[] __read_mostly = {
 107         {
 108                 .name           = "NFQUEUE",
 109                 .family         = NFPROTO_UNSPEC,
 110                 .target         = nfqueue_tg,
 111                 .targetsize     = sizeof(struct xt_NFQ_info),
 112                 .me             = THIS_MODULE,
 113         },
 114         {
 115                 .name           = "NFQUEUE",
 116                 .revision       = 1,
 117                 .family         = NFPROTO_UNSPEC,
 118                 .checkentry     = nfqueue_tg_v1_check,
 119                 .target         = nfqueue_tg_v1,
 120                 .targetsize     = sizeof(struct xt_NFQ_info_v1),
 121                 .me             = THIS_MODULE,
 122         },
 123 };
 124
 125 static int __init nfqueue_tg_init(void)
 126 {
 127         return xt_register_targets(nfqueue_tg_reg, ARRAY_SIZE(nfqueue_tg_reg));
 128 }
 129
 130 static void __exit nfqueue_tg_exit(void)
 131 {
 132         xt_unregister_targets(nfqueue_tg_reg, ARRAY_SIZE(nfqueue_tg_reg));
 133 }
 134
 135 module_init(nfqueue_tg_init);
 136 module_exit(nfqueue_tg_exit);