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
  32 static unsigned int
  33 nfqueue_tg(struct sk_buff *skb, const struct xt_target_param *par)
  34 {
  35         const struct xt_NFQ_info *tinfo = par->targinfo;
  36
  37         return NF_QUEUE_NR(tinfo->queuenum);
  38 }
  39
  40 static u32 hash_v4(const struct sk_buff *skb)
  41 {
  42         const struct iphdr *iph = ip_hdr(skb);
  43         u32 ipaddr;
  44
  45         /* packets in either direction go into same queue */
  46         ipaddr = iph->saddr ^ iph->daddr;
  47
  48         return jhash_2words(ipaddr, iph->protocol, jhash_initval);
  49 }
  50
  51 static unsigned int
  52 nfqueue_tg4_v1(struct sk_buff *skb, const struct xt_target_param *par)
  53 {
  54         const struct xt_NFQ_info_v1 *info = par->targinfo;
  55         u32 queue = info->queuenum;
  56
  57         if (info->queues_total > 1)
  58                 queue = hash_v4(skb) % info->queues_total + queue;
  59         return NF_QUEUE_NR(queue);
  60 }
  61
  62 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
  63 static u32 hash_v6(const struct sk_buff *skb)
  64 {
  65         const struct ipv6hdr *ip6h = ipv6_hdr(skb);
  66         u32 addr[4];
  67
  68         addr[0] = ip6h->saddr.s6_addr32[0] ^ ip6h->daddr.s6_addr32[0];
  69         addr[1] = ip6h->saddr.s6_addr32[1] ^ ip6h->daddr.s6_addr32[1];
  70         addr[2] = ip6h->saddr.s6_addr32[2] ^ ip6h->daddr.s6_addr32[2];
  71         addr[3] = ip6h->saddr.s6_addr32[3] ^ ip6h->daddr.s6_addr32[3];
  72
  73         return jhash2(addr, ARRAY_SIZE(addr), jhash_initval);
  74 }
  75
  76 static unsigned int
  77 nfqueue_tg6_v1(struct sk_buff *skb, const struct xt_target_param *par)
  78 {
  79         const struct xt_NFQ_info_v1 *info = par->targinfo;
  80         u32 queue = info->queuenum;
  81
  82         if (info->queues_total > 1)
  83                 queue = hash_v6(skb) % info->queues_total + queue;
  84         return NF_QUEUE_NR(queue);
  85 }
  86 #endif
  87
  88 static bool nfqueue_tg_v1_check(const struct xt_tgchk_param *par)
  89 {
  90         const struct xt_NFQ_info_v1 *info = par->targinfo;
  91         u32 maxid;
  92
  93         if (info->queues_total == 0) {
  94                 pr_err("NFQUEUE: number of total queues is 0\n");
  95                 return false;
  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 false;
 102         }
 103         return true;
 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_IPV4,
 118                 .checkentry     = nfqueue_tg_v1_check,
 119                 .target         = nfqueue_tg4_v1,
 120                 .targetsize     = sizeof(struct xt_NFQ_info_v1),
 121                 .me             = THIS_MODULE,
 122         },
 123 #if defined(CONFIG_IP6_NF_IPTABLES) || defined(CONFIG_IP6_NF_IPTABLES_MODULE)
 124         {
 125                 .name           = "NFQUEUE",
 126                 .revision       = 1,
 127                 .family         = NFPROTO_IPV6,
 128                 .checkentry     = nfqueue_tg_v1_check,
 129                 .target         = nfqueue_tg6_v1,
 130                 .targetsize     = sizeof(struct xt_NFQ_info_v1),
 131                 .me             = THIS_MODULE,
 132         },
 133 #endif
 134 };
 135
 136 static int __init nfqueue_tg_init(void)
 137 {
 138         get_random_bytes(&jhash_initval, sizeof(jhash_initval));
 139         return xt_register_targets(nfqueue_tg_reg, ARRAY_SIZE(nfqueue_tg_reg));
 140 }
 141
 142 static void __exit nfqueue_tg_exit(void)
 143 {
 144         xt_unregister_targets(nfqueue_tg_reg, ARRAY_SIZE(nfqueue_tg_reg));
 145 }
 146
 147 module_init(nfqueue_tg_init);
 148 module_exit(nfqueue_tg_exit);