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
  26 static int cpu_mt_check(const struct xt_mtchk_param *par)
  27 {
  28         const struct xt_cpu_info *info = par->matchinfo;
  29
  30         if (info->invert & ~1)
  31                 return -EINVAL;
  32         return 0;
  33 }
  34
  35 static bool cpu_mt(const struct sk_buff *skb, struct xt_action_param *par)
  36 {
  37         const struct xt_cpu_info *info = par->matchinfo;
  38
  39         return (info->cpu == smp_processor_id()) ^ info->invert;
  40 }
  41
  42 static struct xt_match cpu_mt_reg __read_mostly = {
  43         .name       = "cpu",
  44         .revision   = 0,
  45         .family     = NFPROTO_UNSPEC,
  46         .checkentry = cpu_mt_check,
  47         .match      = cpu_mt,
  48         .matchsize  = sizeof(struct xt_cpu_info),
  49         .me         = THIS_MODULE,
  50 };
  51
  52 static int __init cpu_mt_init(void)
  53 {
  54         return xt_register_match(&cpu_mt_reg);
  55 }
  56
  57 static void __exit cpu_mt_exit(void)
  58 {
  59         xt_unregister_match(&cpu_mt_reg);
  60 }
  61
  62 module_init(cpu_mt_init);
  63 module_exit(cpu_mt_exit);