LXR linux/net/netfilter/xt

   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
  23MODULE_AUTHOR("Harald Welte <laforge@netfilter.org>");
  24MODULE_DESCRIPTION("Xtables: packet forwarding to netlink");
  25MODULE_LICENSE("GPL");
  26MODULE_ALIAS("ipt_NFQUEUE");
  27MODULE_ALIAS("ip6t_NFQUEUE");
  28MODULE_ALIAS("arpt_NFQUEUE");
  29
  30static u32 jhash_initval __read_mostly;
  31static bool rnd_inited __read_mostly;
  32
  33static unsigned int
  34nfqueue_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
  41static 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)
  53static 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
  67static unsigned int
  68nfqueue_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
  84static 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
 106static 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
 125static int __init nfqueue_tg_init(void)
 126{
 127        return xt_register_targets(nfqueue_tg_reg, ARRAY_SIZE(nfqueue_tg_reg));
 128}
 129
 130static void __exit nfqueue_tg_exit(void)
 131{
 132        xt_unregister_targets(nfqueue_tg_reg, ARRAY_SIZE(nfqueue_tg_reg));
 133}
 134
 135module_init(nfqueue_tg_init);
 136module_exit(nfqueue_tg_exit);
 137