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 ((__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)
  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 ((__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
  79 static u32
  80 nfqueue_hash(const 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 (par->family == NFPROTO_IPV4)
  86                 queue += ((u64) hash_v4(skb) * info->queues_total) >> 32;
  87 #if IS_ENABLED(CONFIG_IP6_NF_IPTABLES)
  88         else if (par->family == NFPROTO_IPV6)
  89                 queue += ((u64) hash_v6(skb) * info->queues_total) >> 32;
  90 #endif
  91
  92         return queue;
  93 }
  94
  95 static unsigned int
  96 nfqueue_tg_v1(struct sk_buff *skb, const struct xt_action_param *par)
  97 {
  98         const struct xt_NFQ_info_v1 *info = par->targinfo;
  99         u32 queue = info->queuenum;
 100
 101         if (info->queues_total > 1)
 102                 queue = nfqueue_hash(skb, par);
 103
 104         return NF_QUEUE_NR(queue);
 105 }
 106
 107 static unsigned int
 108 nfqueue_tg_v2(struct sk_buff *skb, const struct xt_action_param *par)
 109 {
 110         const struct xt_NFQ_info_v2 *info = par->targinfo;
 111         unsigned int ret = nfqueue_tg_v1(skb, par);
 112
 113         if (info->bypass)
 114                 ret |= NF_VERDICT_FLAG_QUEUE_BYPASS;
 115         return ret;
 116 }
 117
 118 static int nfqueue_tg_check(const struct xt_tgchk_param *par)
 119 {
 120         const struct xt_NFQ_info_v3 *info = par->targinfo;
 121         u32 maxid;
 122
 123         if (unlikely(!rnd_inited)) {
 124                 get_random_bytes(&jhash_initval, sizeof(jhash_initval));
 125                 rnd_inited = true;
 126         }
 127         if (info->queues_total == 0) {
 128                 pr_err("NFQUEUE: number of total queues is 0\n");
 129                 return -EINVAL;
 130         }
 131         maxid = info->queues_total - 1 + info->queuenum;
 132         if (maxid > 0xffff) {
 133                 pr_err("NFQUEUE: number of queues (%u) out of range (got %u)\n",
 134                        info->queues_total, maxid);
 135                 return -ERANGE;
 136         }
 137         if (par->target->revision == 2 && info->flags > 1)
 138                 return -EINVAL;
 139         if (par->target->revision == 3 && info->flags & ~NFQ_FLAG_MASK)
 140                 return -EINVAL;
 141
 142         return 0;
 143 }
 144
 145 static unsigned int
 146 nfqueue_tg_v3(struct sk_buff *skb, const struct xt_action_param *par)
 147 {
 148         const struct xt_NFQ_info_v3 *info = par->targinfo;
 149         u32 queue = info->queuenum;
 150         int ret;
 151
 152         if (info->queues_total > 1) {
 153                 if (info->flags & NFQ_FLAG_CPU_FANOUT) {
 154                         int cpu = smp_processor_id();
 155
 156                         queue = info->queuenum + cpu % info->queues_total;
 157                 } else
 158                         queue = nfqueue_hash(skb, par);
 159         }
 160
 161         ret = NF_QUEUE_NR(queue);
 162         if (info->flags & NFQ_FLAG_BYPASS)
 163                 ret |= NF_VERDICT_FLAG_QUEUE_BYPASS;
 164
 165         return ret;
 166 }
 167
 168 static struct xt_target nfqueue_tg_reg[] __read_mostly = {
 169         {
 170                 .name           = "NFQUEUE",
 171                 .family         = NFPROTO_UNSPEC,
 172                 .target         = nfqueue_tg,
 173                 .targetsize     = sizeof(struct xt_NFQ_info),
 174                 .me             = THIS_MODULE,
 175         },
 176         {
 177                 .name           = "NFQUEUE",
 178                 .revision       = 1,
 179                 .family         = NFPROTO_UNSPEC,
 180                 .checkentry     = nfqueue_tg_check,
 181                 .target         = nfqueue_tg_v1,
 182                 .targetsize     = sizeof(struct xt_NFQ_info_v1),
 183                 .me             = THIS_MODULE,
 184         },
 185         {
 186                 .name           = "NFQUEUE",
 187                 .revision       = 2,
 188                 .family         = NFPROTO_UNSPEC,
 189                 .checkentry     = nfqueue_tg_check,
 190                 .target         = nfqueue_tg_v2,
 191                 .targetsize     = sizeof(struct xt_NFQ_info_v2),
 192                 .me             = THIS_MODULE,
 193         },
 194         {
 195                 .name           = "NFQUEUE",
 196                 .revision       = 3,
 197                 .family         = NFPROTO_UNSPEC,
 198                 .checkentry     = nfqueue_tg_check,
 199                 .target         = nfqueue_tg_v3,
 200                 .targetsize     = sizeof(struct xt_NFQ_info_v3),
 201                 .me             = THIS_MODULE,
 202         },
 203 };
 204
 205 static int __init nfqueue_tg_init(void)
 206 {
 207         return xt_register_targets(nfqueue_tg_reg, ARRAY_SIZE(nfqueue_tg_reg));
 208 }
 209
 210 static void __exit nfqueue_tg_exit(void)
 211 {
 212         xt_unregister_targets(nfqueue_tg_reg, ARRAY_SIZE(nfqueue_tg_reg));
 213 }
 214
 215 module_init(nfqueue_tg_init);
 216 module_exit(nfqueue_tg_exit);