net/netfilter/xt_cpu.c

   1 /* Kernel module to match running CPU */
   2
   3 /*
   4  * Might be used to distribute connections on several daemons, if
   5  * RPS (Remote Packet Steering) is enabled or NIC is multiqueue capable,
   6  * each RX queue IRQ affined to one CPU (1:1 mapping)
   7  *
   8  */
   9
  10 /* (C) 2010 Eric Dumazet
  11  *
  12  * This program is free software; you can redistribute it and/or modify
  13  * it under the terms of the GNU General Public License version 2 as
  14  * published by the Free Software Foundation.
  15  */
  16
  17 #include <linux/module.h>
  18 #include <linux/skbuff.h>
  19 #include <linux/netfilter/xt_cpu.h>
  20 #include <linux/netfilter/x_tables.h>
  21
  22 MODULE_LICENSE("GPL");
  23 MODULE_AUTHOR("Eric Dumazet <eric.dumazet@gmail.com>");
  24 MODULE_DESCRIPTION("Xtables: CPU match");
  25 MODULE_ALIAS("ipt_cpu");
  26 MODULE_ALIAS("ip6t_cpu");
  27
  28 static int cpu_mt_check(const struct xt_mtchk_param *par)
  29 {
  30         const struct xt_cpu_info *info = par->matchinfo;
  31
  32         if (info->invert & ~1)
  33                 return -EINVAL;
  34         return 0;
  35 }
  36
  37 static bool cpu_mt(const struct sk_buff *skb, struct xt_action_param *par)
  38 {
  39         const struct xt_cpu_info *info = par->matchinfo;
  40
  41         return (info->cpu == smp_processor_id()) ^ info->invert;
  42 }
  43
  44 static struct xt_match cpu_mt_reg __read_mostly = {
  45         .name       = "cpu",
  46         .revision   = 0,
  47         .family     = NFPROTO_UNSPEC,
  48         .checkentry = cpu_mt_check,
  49         .match      = cpu_mt,
  50         .matchsize  = sizeof(struct xt_cpu_info),
  51         .me         = THIS_MODULE,
  52 };
  53
  54 static int __init cpu_mt_init(void)
  55 {
  56         return xt_register_match(&cpu_mt_reg);
  57 }
  58
  59 static void __exit cpu_mt_exit(void)
  60 {
  61         xt_unregister_match(&cpu_mt_reg);
  62 }
  63
  64 module_init(cpu_mt_init);
  65 module_exit(cpu_mt_exit);