1/* 2 * Filtering ARP tables module. 3 * 4 * Copyright (C) 2002 David S. Miller (davem@redhat.com) 5 * 6 */ 7 8#include <linux/module.h> 9#include <linux/netfilter/x_tables.h> 10#include <linux/netfilter_arp/arp_tables.h> 11#include <linux/slab.h> 12 13MODULE_LICENSE("GPL"); 14MODULE_AUTHOR("David S. Miller <davem@redhat.com>"); 15MODULE_DESCRIPTION("arptables filter table"); 16 17#define FILTER_VALID_HOOKS ((1 << NF_ARP_IN) | (1 << NF_ARP_OUT) | \ 18 (1 << NF_ARP_FORWARD)) 19 20static const struct xt_table packet_filter = { 21 .name = "filter", 22 .valid_hooks = FILTER_VALID_HOOKS, 23 .me = THIS_MODULE, 24 .af = NFPROTO_ARP, 25 .priority = NF_IP_PRI_FILTER, 26}; 27 28/* The work comes in here from netfilter.c */ 29static unsigned int 30arptable_filter_hook(unsigned int hook, struct sk_buff *skb, 31 const struct net_device *in, const struct net_device *out, 32 int (*okfn)(struct sk_buff *)) 33{ 34 const struct net *net = dev_net((in != NULL) ? in : out); 35 36 return arpt_do_table(skb, hook, in, out, net->ipv4.arptable_filter); 37} 38 39static struct nf_hook_ops *arpfilter_ops __read_mostly; 40 41static int __net_init arptable_filter_net_init(struct net *net) 42{ 43 struct arpt_replace *repl; 44 45 repl = arpt_alloc_initial_table(&packet_filter); 46 if (repl == NULL) 47 return -ENOMEM; 48 net->ipv4.arptable_filter = 49 arpt_register_table(net, &packet_filter, repl); 50 kfree(repl); 51 if (IS_ERR(net->ipv4.arptable_filter)) 52 return PTR_ERR(net->ipv4.arptable_filter); 53 return 0; 54} 55 56static void __net_exit arptable_filter_net_exit(struct net *net) 57{ 58 arpt_unregister_table(net->ipv4.arptable_filter); 59} 60 61static struct pernet_operations arptable_filter_net_ops = { 62 .init = arptable_filter_net_init, 63 .exit = arptable_filter_net_exit, 64}; 65 66static int __init arptable_filter_init(void) 67{ 68 int ret; 69 70 ret = register_pernet_subsys(&arptable_filter_net_ops); 71 if (ret < 0) 72 return ret; 73 74 arpfilter_ops = xt_hook_link(&packet_filter, arptable_filter_hook); 75 if (IS_ERR(arpfilter_ops)) { 76 ret = PTR_ERR(arpfilter_ops); 77 goto cleanup_table; 78 } 79 return ret; 80 81cleanup_table: 82 unregister_pernet_subsys(&arptable_filter_net_ops); 83 return ret; 84} 85 86static void __exit arptable_filter_fini(void) 87{ 88 xt_hook_unlink(&packet_filter, arpfilter_ops); 89 unregister_pernet_subsys(&arptable_filter_net_ops); 90} 91 92module_init(arptable_filter_init); 93module_exit(arptable_filter_fini); 94