net/netfilter/xt_cpu.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* Kernel module to match running CPU */
   3
   4 /*
   5  * Might be used to distribute connections on several daemons, if
   6  * RPS (Remote Packet Steering) is enabled or NIC is multiqueue capable,
   7  * each RX queue IRQ affined to one CPU (1:1 mapping)
   8  */
   9
  10 /* (C) 2010 Eric Dumazet
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/skbuff.h>
  15 #include <linux/netfilter/xt_cpu.h>
  16 #include <linux/netfilter/x_tables.h>
  17
  18 MODULE_LICENSE("GPL");
  19 MODULE_AUTHOR("Eric Dumazet <eric.dumazet@gmail.com>");
  20 MODULE_DESCRIPTION("Xtables: CPU match");
  21 MODULE_ALIAS("ipt_cpu");
  22 MODULE_ALIAS("ip6t_cpu");
  23
  24 static int cpu_mt_check(const struct xt_mtchk_param *par)
  25 {
  26         const struct xt_cpu_info *info = par->matchinfo;
  27
  28         if (info->invert & ~1)
  29                 return -EINVAL;
  30         return 0;
  31 }
  32
  33 static bool cpu_mt(const struct sk_buff *skb, struct xt_action_param *par)
  34 {
  35         const struct xt_cpu_info *info = par->matchinfo;
  36
  37         return (info->cpu == smp_processor_id()) ^ info->invert;
  38 }
  39
  40 static struct xt_match cpu_mt_reg __read_mostly = {
  41         .name       = "cpu",
  42         .revision   = 0,
  43         .family     = NFPROTO_UNSPEC,
  44         .checkentry = cpu_mt_check,
  45         .match      = cpu_mt,
  46         .matchsize  = sizeof(struct xt_cpu_info),
  47         .me         = THIS_MODULE,
  48 };
  49
  50 static int __init cpu_mt_init(void)
  51 {
  52         return xt_register_match(&cpu_mt_reg);
  53 }
  54
  55 static void __exit cpu_mt_exit(void)
  56 {
  57         xt_unregister_match(&cpu_mt_reg);
  58 }
  59
  60 module_init(cpu_mt_init);
  61 module_exit(cpu_mt_exit);