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