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_target_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 static unsigned int
  53 nfqueue_tg4_v1(struct sk_buff *skb, const struct xt_target_param *par)
  54 {
  55         const struct xt_NFQ_info_v1 *info = par->targinfo;
  56         u32 queue = info->queuenum;
  57
  58         if (info->queues_total > 1)
  59                 queue = hash_v4(skb) % info->queues_total + queue;
  60         return NF_QUEUE_NR(queue);
  61 }
  62
  63 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
  64 static u32 hash_v6(const struct sk_buff *skb)
  65 {
  66         const struct ipv6hdr *ip6h = ipv6_hdr(skb);
  67         __be32 addr[4];
  68
  69         addr[0] = ip6h->saddr.s6_addr32[0] ^ ip6h->daddr.s6_addr32[0];
  70         addr[1] = ip6h->saddr.s6_addr32[1] ^ ip6h->daddr.s6_addr32[1];
  71         addr[2] = ip6h->saddr.s6_addr32[2] ^ ip6h->daddr.s6_addr32[2];
  72         addr[3] = ip6h->saddr.s6_addr32[3] ^ ip6h->daddr.s6_addr32[3];
  73
  74         return jhash2((__force u32 *)addr, ARRAY_SIZE(addr), jhash_initval);
  75 }
  76
  77 static unsigned int
  78 nfqueue_tg6_v1(struct sk_buff *skb, const struct xt_target_param *par)
  79 {
  80         const struct xt_NFQ_info_v1 *info = par->targinfo;
  81         u32 queue = info->queuenum;
  82
  83         if (info->queues_total > 1)
  84                 queue = hash_v6(skb) % info->queues_total + queue;
  85         return NF_QUEUE_NR(queue);
  86 }
  87 #endif
  88
  89 static bool nfqueue_tg_v1_check(const struct xt_tgchk_param *par)
  90 {
  91         const struct xt_NFQ_info_v1 *info = par->targinfo;
  92         u32 maxid;
  93
  94         if (unlikely(!rnd_inited)) {
  95                 get_random_bytes(&jhash_initval, sizeof(jhash_initval));
  96                 rnd_inited = true;
  97         }
  98         if (info->queues_total == 0) {
  99                 pr_err("NFQUEUE: number of total queues is 0\n");
 100                 return false;
 101         }
 102         maxid = info->queues_total - 1 + info->queuenum;
 103         if (maxid > 0xffff) {
 104                 pr_err("NFQUEUE: number of queues (%u) out of range (got %u)\n",
 105                        info->queues_total, maxid);
 106                 return false;
 107         }
 108         return true;
 109 }
 110
 111 static struct xt_target nfqueue_tg_reg[] __read_mostly = {
 112         {
 113                 .name           = "NFQUEUE",
 114                 .family         = NFPROTO_UNSPEC,
 115                 .target         = nfqueue_tg,
 116                 .targetsize     = sizeof(struct xt_NFQ_info),
 117                 .me             = THIS_MODULE,
 118         },
 119         {
 120                 .name           = "NFQUEUE",
 121                 .revision       = 1,
 122                 .family         = NFPROTO_IPV4,
 123                 .checkentry     = nfqueue_tg_v1_check,
 124                 .target         = nfqueue_tg4_v1,
 125                 .targetsize     = sizeof(struct xt_NFQ_info_v1),
 126                 .me             = THIS_MODULE,
 127         },
 128 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
 129         {
 130                 .name           = "NFQUEUE",
 131                 .revision       = 1,
 132                 .family         = NFPROTO_IPV6,
 133                 .checkentry     = nfqueue_tg_v1_check,
 134                 .target         = nfqueue_tg6_v1,
 135                 .targetsize     = sizeof(struct xt_NFQ_info_v1),
 136                 .me             = THIS_MODULE,
 137         },
 138 #endif
 139 };
 140
 141 static int __init nfqueue_tg_init(void)
 142 {
 143         return xt_register_targets(nfqueue_tg_reg, ARRAY_SIZE(nfqueue_tg_reg));
 144 }
 145
 146 static void __exit nfqueue_tg_exit(void)
 147 {
 148         xt_unregister_targets(nfqueue_tg_reg, ARRAY_SIZE(nfqueue_tg_reg));
 149 }
 150
 151 module_init(nfqueue_tg_init);
 152 module_exit(nfqueue_tg_exit);