linux/net/netfilter/xt_NFQUEUE.c
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   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
  45        /* packets in either direction go into same queue */
  46        if ((__force u32)iph->saddr < (__force u32)iph->daddr)
  47                return jhash_3words((__force u32)iph->saddr,
  48                        (__force u32)iph->daddr, iph->protocol, jhash_initval);
  49
  50        return jhash_3words((__force u32)iph->daddr,
  51                        (__force u32)iph->saddr, iph->protocol, jhash_initval);
  52}
  53
  54#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
  55static u32 hash_v6(const struct sk_buff *skb)
  56{
  57        const struct ipv6hdr *ip6h = ipv6_hdr(skb);
  58        u32 a, b, c;
  59
  60        if ((__force u32)ip6h->saddr.s6_addr32[3] <
  61            (__force u32)ip6h->daddr.s6_addr32[3]) {
  62                a = (__force u32) ip6h->saddr.s6_addr32[3];
  63                b = (__force u32) ip6h->daddr.s6_addr32[3];
  64        } else {
  65                b = (__force u32) ip6h->saddr.s6_addr32[3];
  66                a = (__force u32) ip6h->daddr.s6_addr32[3];
  67        }
  68
  69        if ((__force u32)ip6h->saddr.s6_addr32[1] <
  70            (__force u32)ip6h->daddr.s6_addr32[1])
  71                c = (__force u32) ip6h->saddr.s6_addr32[1];
  72        else
  73                c = (__force u32) ip6h->daddr.s6_addr32[1];
  74
  75        return jhash_3words(a, b, c, jhash_initval);
  76}
  77#endif
  78
  79static unsigned int
  80nfqueue_tg_v1(struct sk_buff *skb, const struct xt_action_param *par)
  81{
  82        const struct xt_NFQ_info_v1 *info = par->targinfo;
  83        u32 queue = info->queuenum;
  84
  85        if (info->queues_total > 1) {
  86                if (par->family == NFPROTO_IPV4)
  87                        queue = (((u64) hash_v4(skb) * info->queues_total) >>
  88                                 32) + queue;
  89#if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
  90                else if (par->family == NFPROTO_IPV6)
  91                        queue = (((u64) hash_v6(skb) * info->queues_total) >>
  92                                 32) + queue;
  93#endif
  94        }
  95        return NF_QUEUE_NR(queue);
  96}
  97
  98static unsigned int
  99nfqueue_tg_v2(struct sk_buff *skb, const struct xt_action_param *par)
 100{
 101        const struct xt_NFQ_info_v2 *info = par->targinfo;
 102        unsigned int ret = nfqueue_tg_v1(skb, par);
 103
 104        if (info->bypass)
 105                ret |= NF_VERDICT_FLAG_QUEUE_BYPASS;
 106        return ret;
 107}
 108
 109static int nfqueue_tg_check(const struct xt_tgchk_param *par)
 110{
 111        const struct xt_NFQ_info_v2 *info = par->targinfo;
 112        u32 maxid;
 113
 114        if (unlikely(!rnd_inited)) {
 115                get_random_bytes(&jhash_initval, sizeof(jhash_initval));
 116                rnd_inited = true;
 117        }
 118        if (info->queues_total == 0) {
 119                pr_err("NFQUEUE: number of total queues is 0\n");
 120                return -EINVAL;
 121        }
 122        maxid = info->queues_total - 1 + info->queuenum;
 123        if (maxid > 0xffff) {
 124                pr_err("NFQUEUE: number of queues (%u) out of range (got %u)\n",
 125                       info->queues_total, maxid);
 126                return -ERANGE;
 127        }
 128        if (par->target->revision == 2 && info->bypass > 1)
 129                return -EINVAL;
 130        return 0;
 131}
 132
 133static struct xt_target nfqueue_tg_reg[] __read_mostly = {
 134        {
 135                .name           = "NFQUEUE",
 136                .family         = NFPROTO_UNSPEC,
 137                .target         = nfqueue_tg,
 138                .targetsize     = sizeof(struct xt_NFQ_info),
 139                .me             = THIS_MODULE,
 140        },
 141        {
 142                .name           = "NFQUEUE",
 143                .revision       = 1,
 144                .family         = NFPROTO_UNSPEC,
 145                .checkentry     = nfqueue_tg_check,
 146                .target         = nfqueue_tg_v1,
 147                .targetsize     = sizeof(struct xt_NFQ_info_v1),
 148                .me             = THIS_MODULE,
 149        },
 150        {
 151                .name           = "NFQUEUE",
 152                .revision       = 2,
 153                .family         = NFPROTO_UNSPEC,
 154                .checkentry     = nfqueue_tg_check,
 155                .target         = nfqueue_tg_v2,
 156                .targetsize     = sizeof(struct xt_NFQ_info_v2),
 157                .me             = THIS_MODULE,
 158        },
 159};
 160
 161static int __init nfqueue_tg_init(void)
 162{
 163        return xt_register_targets(nfqueue_tg_reg, ARRAY_SIZE(nfqueue_tg_reg));
 164}
 165
 166static void __exit nfqueue_tg_exit(void)
 167{
 168        xt_unregister_targets(nfqueue_tg_reg, ARRAY_SIZE(nfqueue_tg_reg));
 169}
 170
 171module_init(nfqueue_tg_init);
 172module_exit(nfqueue_tg_exit);
 173
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