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 14 MODULE_LICENSE("GPL"); 15 MODULE_AUTHOR("David S. Miller <davem@redhat.com>"); 16 MODULE_DESCRIPTION("arptables filter table"); 17 18 #define FILTER_VALID_HOOKS ((1 << NF_ARP_IN) | (1 << NF_ARP_OUT) | \ 19 (1 << NF_ARP_FORWARD)) 20 21 static int __net_init arptable_filter_table_init(struct net *net); 22 23 static const struct xt_table packet_filter = { 24 .name = "filter", 25 .valid_hooks = FILTER_VALID_HOOKS, 26 .me = THIS_MODULE, 27 .af = NFPROTO_ARP, 28 .priority = NF_IP_PRI_FILTER, 29 .table_init = arptable_filter_table_init, 30 }; 31 32 /* The work comes in here from netfilter.c */ 33 static unsigned int 34 arptable_filter_hook(void *priv, struct sk_buff *skb, 35 const struct nf_hook_state *state) 36 { 37 return arpt_do_table(skb, state, priv); 38 } 39 40 static struct nf_hook_ops *arpfilter_ops __read_mostly; 41 42 static int __net_init arptable_filter_table_init(struct net *net) 43 { 44 struct arpt_replace *repl; 45 int err; 46 47 repl = arpt_alloc_initial_table(&packet_filter); 48 if (repl == NULL) 49 return -ENOMEM; 50 err = arpt_register_table(net, &packet_filter, repl, arpfilter_ops); 51 kfree(repl); 52 return err; 53 } 54 55 static void __net_exit arptable_filter_net_pre_exit(struct net *net) 56 { 57 arpt_unregister_table_pre_exit(net, "filter"); 58 } 59 60 static void __net_exit arptable_filter_net_exit(struct net *net) 61 { 62 arpt_unregister_table(net, "filter"); 63 } 64 65 static struct pernet_operations arptable_filter_net_ops = { 66 .exit = arptable_filter_net_exit, 67 .pre_exit = arptable_filter_net_pre_exit, 68 }; 69 70 static int __init arptable_filter_init(void) 71 { 72 int ret; 73 74 arpfilter_ops = xt_hook_ops_alloc(&packet_filter, arptable_filter_hook); 75 if (IS_ERR(arpfilter_ops)) 76 return PTR_ERR(arpfilter_ops); 77 78 ret = register_pernet_subsys(&arptable_filter_net_ops); 79 if (ret < 0) { 80 kfree(arpfilter_ops); 81 return ret; 82 } 83 84 ret = arptable_filter_table_init(&init_net); 85 if (ret) { 86 unregister_pernet_subsys(&arptable_filter_net_ops); 87 kfree(arpfilter_ops); 88 } 89 90 return ret; 91 } 92 93 static void __exit arptable_filter_fini(void) 94 { 95 unregister_pernet_subsys(&arptable_filter_net_ops); 96 kfree(arpfilter_ops); 97 } 98 99 module_init(arptable_filter_init); 100 module_exit(arptable_filter_fini); 101