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
18MODULE_LICENSE("GPL");
19MODULE_AUTHOR("Eric Dumazet <eric.dumazet@gmail.com>");
20MODULE_DESCRIPTION("Xtables: CPU match");
21MODULE_ALIAS("ipt_cpu");
22MODULE_ALIAS("ip6t_cpu");
23
24static 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
33static 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
40static 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
50static int __init cpu_mt_init(void)
51{
52 return xt_register_match(target: &cpu_mt_reg);
53}
54
55static void __exit cpu_mt_exit(void)
56{
57 xt_unregister_match(target: &cpu_mt_reg);
58}
59
60module_init(cpu_mt_init);
61module_exit(cpu_mt_exit);
62

source code of linux/net/netfilter/xt_cpu.c