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- // SPDX-License-Identifier: GPL-2.0-only
- /*
- * Filtering ARP tables module.
- *
- * Copyright (C) 2002 David S. Miller (davem@redhat.com)
- *
- */
- #include <linux/module.h>
- #include <linux/netfilter/x_tables.h>
- #include <linux/netfilter_arp/arp_tables.h>
- #include <linux/slab.h>
- MODULE_LICENSE("GPL");
- MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
- MODULE_DESCRIPTION("arptables filter table");
- #define FILTER_VALID_HOOKS ((1 << NF_ARP_IN) | (1 << NF_ARP_OUT) | \
- (1 << NF_ARP_FORWARD))
- static int __net_init arptable_filter_table_init(struct net *net);
- static const struct xt_table packet_filter = {
- .name = "filter",
- .valid_hooks = FILTER_VALID_HOOKS,
- .me = THIS_MODULE,
- .af = NFPROTO_ARP,
- .priority = NF_IP_PRI_FILTER,
- .table_init = arptable_filter_table_init,
- };
- /* The work comes in here from netfilter.c */
- static unsigned int
- arptable_filter_hook(void *priv, struct sk_buff *skb,
- const struct nf_hook_state *state)
- {
- return arpt_do_table(skb, state, state->net->ipv4.arptable_filter);
- }
- static struct nf_hook_ops *arpfilter_ops __read_mostly;
- static int __net_init arptable_filter_table_init(struct net *net)
- {
- struct arpt_replace *repl;
- int err;
- if (net->ipv4.arptable_filter)
- return 0;
- repl = arpt_alloc_initial_table(&packet_filter);
- if (repl == NULL)
- return -ENOMEM;
- err = arpt_register_table(net, &packet_filter, repl, arpfilter_ops,
- &net->ipv4.arptable_filter);
- kfree(repl);
- return err;
- }
- static void __net_exit arptable_filter_net_pre_exit(struct net *net)
- {
- if (net->ipv4.arptable_filter)
- arpt_unregister_table_pre_exit(net, net->ipv4.arptable_filter,
- arpfilter_ops);
- }
- static void __net_exit arptable_filter_net_exit(struct net *net)
- {
- if (!net->ipv4.arptable_filter)
- return;
- arpt_unregister_table(net, net->ipv4.arptable_filter);
- net->ipv4.arptable_filter = NULL;
- }
- static struct pernet_operations arptable_filter_net_ops = {
- .exit = arptable_filter_net_exit,
- .pre_exit = arptable_filter_net_pre_exit,
- };
- static int __init arptable_filter_init(void)
- {
- int ret;
- arpfilter_ops = xt_hook_ops_alloc(&packet_filter, arptable_filter_hook);
- if (IS_ERR(arpfilter_ops))
- return PTR_ERR(arpfilter_ops);
- ret = register_pernet_subsys(&arptable_filter_net_ops);
- if (ret < 0) {
- kfree(arpfilter_ops);
- return ret;
- }
- ret = arptable_filter_table_init(&init_net);
- if (ret) {
- unregister_pernet_subsys(&arptable_filter_net_ops);
- kfree(arpfilter_ops);
- }
- return ret;
- }
- static void __exit arptable_filter_fini(void)
- {
- unregister_pernet_subsys(&arptable_filter_net_ops);
- kfree(arpfilter_ops);
- }
- module_init(arptable_filter_init);
- module_exit(arptable_filter_fini);
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