LXR linux/net/ipv4/netfilter/arptable

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * Filtering ARP tables module.
   4 *
   5 * Copyright (C) 2002 David S. Miller (davem@redhat.com)
   6 *
   7 */
   8
   9#include <linux/module.h>
  10#include <linux/netfilter/x_tables.h>
  11#include <linux/netfilter_arp/arp_tables.h>
  12#include <linux/slab.h>
  13
  14MODULE_LICENSE("GPL");
  15MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
  16MODULE_DESCRIPTION("arptables filter table");
  17
  18#define FILTER_VALID_HOOKS ((1 << NF_ARP_IN) | (1 << NF_ARP_OUT) | \
  19                           (1 << NF_ARP_FORWARD))
  20
  21static const struct xt_table packet_filter = {
  22        .name           = "filter",
  23        .valid_hooks    = FILTER_VALID_HOOKS,
  24        .me             = THIS_MODULE,
  25        .af             = NFPROTO_ARP,
  26        .priority       = NF_IP_PRI_FILTER,
  27};
  28
  29/* The work comes in here from netfilter.c */
  30static unsigned int
  31arptable_filter_hook(void *priv, struct sk_buff *skb,
  32                     const struct nf_hook_state *state)
  33{
  34        return arpt_do_table(skb, state, priv);
  35}
  36
  37static struct nf_hook_ops *arpfilter_ops __read_mostly;
  38
  39static int arptable_filter_table_init(struct net *net)
  40{
  41        struct arpt_replace *repl;
  42        int err;
  43
  44        repl = arpt_alloc_initial_table(&packet_filter);
  45        if (repl == NULL)
  46                return -ENOMEM;
  47        err = arpt_register_table(net, &packet_filter, repl, arpfilter_ops);
  48        kfree(repl);
  49        return err;
  50}
  51
  52static void __net_exit arptable_filter_net_pre_exit(struct net *net)
  53{
  54        arpt_unregister_table_pre_exit(net, "filter");
  55}
  56
  57static void __net_exit arptable_filter_net_exit(struct net *net)
  58{
  59        arpt_unregister_table(net, "filter");
  60}
  61
  62static struct pernet_operations arptable_filter_net_ops = {
  63        .exit = arptable_filter_net_exit,
  64        .pre_exit = arptable_filter_net_pre_exit,
  65};
  66
  67static int __init arptable_filter_init(void)
  68{
  69        int ret = xt_register_template(&packet_filter,
  70                                       arptable_filter_table_init);
  71
  72        if (ret < 0)
  73                return ret;
  74
  75        arpfilter_ops = xt_hook_ops_alloc(&packet_filter, arptable_filter_hook);
  76        if (IS_ERR(arpfilter_ops)) {
  77                xt_unregister_template(&packet_filter);
  78                return PTR_ERR(arpfilter_ops);
  79        }
  80
  81        ret = register_pernet_subsys(&arptable_filter_net_ops);
  82        if (ret < 0) {
  83                xt_unregister_template(&packet_filter);
  84                kfree(arpfilter_ops);
  85                return ret;
  86        }
  87
  88        return ret;
  89}
  90
  91static void __exit arptable_filter_fini(void)
  92{
  93        unregister_pernet_subsys(&arptable_filter_net_ops);
  94        xt_unregister_template(&packet_filter);
  95        kfree(arpfilter_ops);
  96}
  97
  98module_init(arptable_filter_init);
  99module_exit(arptable_filter_fini);
 100