| /* |
| * Filtering ARP tables module. |
| * |
| * Copyright (C) 2002 David S. Miller (davem@redhat.com) |
| * |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/netfilter_arp/arp_tables.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 const struct |
| { |
| struct arpt_replace repl; |
| struct arpt_standard entries[3]; |
| struct arpt_error term; |
| } initial_table __net_initdata = { |
| .repl = { |
| .name = "filter", |
| .valid_hooks = FILTER_VALID_HOOKS, |
| .num_entries = 4, |
| .size = sizeof(struct arpt_standard) * 3 + sizeof(struct arpt_error), |
| .hook_entry = { |
| [NF_ARP_IN] = 0, |
| [NF_ARP_OUT] = sizeof(struct arpt_standard), |
| [NF_ARP_FORWARD] = 2 * sizeof(struct arpt_standard), |
| }, |
| .underflow = { |
| [NF_ARP_IN] = 0, |
| [NF_ARP_OUT] = sizeof(struct arpt_standard), |
| [NF_ARP_FORWARD] = 2 * sizeof(struct arpt_standard), |
| }, |
| }, |
| .entries = { |
| ARPT_STANDARD_INIT(NF_ACCEPT), /* ARP_IN */ |
| ARPT_STANDARD_INIT(NF_ACCEPT), /* ARP_OUT */ |
| ARPT_STANDARD_INIT(NF_ACCEPT), /* ARP_FORWARD */ |
| }, |
| .term = ARPT_ERROR_INIT, |
| }; |
| |
| static const struct xt_table packet_filter = { |
| .name = "filter", |
| .valid_hooks = FILTER_VALID_HOOKS, |
| .me = THIS_MODULE, |
| .af = NFPROTO_ARP, |
| }; |
| |
| /* The work comes in here from netfilter.c */ |
| static unsigned int arpt_in_hook(unsigned int hook, |
| struct sk_buff *skb, |
| const struct net_device *in, |
| const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| return arpt_do_table(skb, hook, in, out, |
| dev_net(in)->ipv4.arptable_filter); |
| } |
| |
| static unsigned int arpt_out_hook(unsigned int hook, |
| struct sk_buff *skb, |
| const struct net_device *in, |
| const struct net_device *out, |
| int (*okfn)(struct sk_buff *)) |
| { |
| return arpt_do_table(skb, hook, in, out, |
| dev_net(out)->ipv4.arptable_filter); |
| } |
| |
| static struct nf_hook_ops arpt_ops[] __read_mostly = { |
| { |
| .hook = arpt_in_hook, |
| .owner = THIS_MODULE, |
| .pf = NFPROTO_ARP, |
| .hooknum = NF_ARP_IN, |
| .priority = NF_IP_PRI_FILTER, |
| }, |
| { |
| .hook = arpt_out_hook, |
| .owner = THIS_MODULE, |
| .pf = NFPROTO_ARP, |
| .hooknum = NF_ARP_OUT, |
| .priority = NF_IP_PRI_FILTER, |
| }, |
| { |
| .hook = arpt_in_hook, |
| .owner = THIS_MODULE, |
| .pf = NFPROTO_ARP, |
| .hooknum = NF_ARP_FORWARD, |
| .priority = NF_IP_PRI_FILTER, |
| }, |
| }; |
| |
| static int __net_init arptable_filter_net_init(struct net *net) |
| { |
| /* Register table */ |
| net->ipv4.arptable_filter = |
| arpt_register_table(net, &packet_filter, &initial_table.repl); |
| if (IS_ERR(net->ipv4.arptable_filter)) |
| return PTR_ERR(net->ipv4.arptable_filter); |
| return 0; |
| } |
| |
| static void __net_exit arptable_filter_net_exit(struct net *net) |
| { |
| arpt_unregister_table(net->ipv4.arptable_filter); |
| } |
| |
| static struct pernet_operations arptable_filter_net_ops = { |
| .init = arptable_filter_net_init, |
| .exit = arptable_filter_net_exit, |
| }; |
| |
| static int __init arptable_filter_init(void) |
| { |
| int ret; |
| |
| ret = register_pernet_subsys(&arptable_filter_net_ops); |
| if (ret < 0) |
| return ret; |
| |
| ret = nf_register_hooks(arpt_ops, ARRAY_SIZE(arpt_ops)); |
| if (ret < 0) |
| goto cleanup_table; |
| return ret; |
| |
| cleanup_table: |
| unregister_pernet_subsys(&arptable_filter_net_ops); |
| return ret; |
| } |
| |
| static void __exit arptable_filter_fini(void) |
| { |
| nf_unregister_hooks(arpt_ops, ARRAY_SIZE(arpt_ops)); |
| unregister_pernet_subsys(&arptable_filter_net_ops); |
| } |
| |
| module_init(arptable_filter_init); |
| module_exit(arptable_filter_fini); |