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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  
cpu_mt_check(const struct xt_mtchk_param * par)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  
cpu_mt(const struct sk_buff * skb,struct xt_action_param * par)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  
cpu_mt_init(void)50  static int __init cpu_mt_init(void)
51  {
52  	return xt_register_match(&cpu_mt_reg);
53  }
54  
cpu_mt_exit(void)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);
62