146 lines
3.4 KiB
C
146 lines
3.4 KiB
C
/*
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* Filtering ARP tables module.
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*
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* Copyright (C) 2002 David S. Miller (davem@redhat.com)
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*
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*/
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#include <linux/module.h>
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#include <linux/netfilter_arp/arp_tables.h>
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MODULE_LICENSE("GPL");
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MODULE_AUTHOR("David S. Miller <davem@redhat.com>");
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MODULE_DESCRIPTION("arptables filter table");
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#define FILTER_VALID_HOOKS ((1 << NF_ARP_IN) | (1 << NF_ARP_OUT) | \
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(1 << NF_ARP_FORWARD))
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static struct
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{
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struct arpt_replace repl;
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struct arpt_standard entries[3];
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struct arpt_error term;
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} initial_table __net_initdata = {
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.repl = {
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.name = "filter",
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.valid_hooks = FILTER_VALID_HOOKS,
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.num_entries = 4,
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.size = sizeof(struct arpt_standard) * 3 + sizeof(struct arpt_error),
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.hook_entry = {
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[NF_ARP_IN] = 0,
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[NF_ARP_OUT] = sizeof(struct arpt_standard),
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[NF_ARP_FORWARD] = 2 * sizeof(struct arpt_standard),
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},
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.underflow = {
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[NF_ARP_IN] = 0,
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[NF_ARP_OUT] = sizeof(struct arpt_standard),
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[NF_ARP_FORWARD] = 2 * sizeof(struct arpt_standard),
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},
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},
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.entries = {
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ARPT_STANDARD_INIT(NF_ACCEPT), /* ARP_IN */
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ARPT_STANDARD_INIT(NF_ACCEPT), /* ARP_OUT */
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ARPT_STANDARD_INIT(NF_ACCEPT), /* ARP_FORWARD */
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},
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.term = ARPT_ERROR_INIT,
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};
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static struct xt_table packet_filter = {
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.name = "filter",
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.valid_hooks = FILTER_VALID_HOOKS,
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.me = THIS_MODULE,
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.af = NFPROTO_ARP,
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};
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/* The work comes in here from netfilter.c */
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static unsigned int arpt_in_hook(unsigned int hook,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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return arpt_do_table(skb, hook, in, out,
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dev_net(in)->ipv4.arptable_filter);
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}
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static unsigned int arpt_out_hook(unsigned int hook,
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struct sk_buff *skb,
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const struct net_device *in,
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const struct net_device *out,
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int (*okfn)(struct sk_buff *))
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{
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return arpt_do_table(skb, hook, in, out,
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dev_net(out)->ipv4.arptable_filter);
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}
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static struct nf_hook_ops arpt_ops[] __read_mostly = {
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{
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.hook = arpt_in_hook,
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.owner = THIS_MODULE,
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.pf = NFPROTO_ARP,
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.hooknum = NF_ARP_IN,
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.priority = NF_IP_PRI_FILTER,
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},
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{
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.hook = arpt_out_hook,
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.owner = THIS_MODULE,
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.pf = NFPROTO_ARP,
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.hooknum = NF_ARP_OUT,
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.priority = NF_IP_PRI_FILTER,
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},
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{
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.hook = arpt_in_hook,
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.owner = THIS_MODULE,
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.pf = NFPROTO_ARP,
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.hooknum = NF_ARP_FORWARD,
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.priority = NF_IP_PRI_FILTER,
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},
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};
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static int __net_init arptable_filter_net_init(struct net *net)
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{
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/* Register table */
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net->ipv4.arptable_filter =
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arpt_register_table(net, &packet_filter, &initial_table.repl);
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if (IS_ERR(net->ipv4.arptable_filter))
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return PTR_ERR(net->ipv4.arptable_filter);
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return 0;
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}
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static void __net_exit arptable_filter_net_exit(struct net *net)
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{
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arpt_unregister_table(net->ipv4.arptable_filter);
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}
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static struct pernet_operations arptable_filter_net_ops = {
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.init = arptable_filter_net_init,
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.exit = arptable_filter_net_exit,
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};
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static int __init arptable_filter_init(void)
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{
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int ret;
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ret = register_pernet_subsys(&arptable_filter_net_ops);
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if (ret < 0)
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return ret;
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ret = nf_register_hooks(arpt_ops, ARRAY_SIZE(arpt_ops));
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if (ret < 0)
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goto cleanup_table;
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return ret;
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cleanup_table:
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unregister_pernet_subsys(&arptable_filter_net_ops);
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return ret;
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}
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static void __exit arptable_filter_fini(void)
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{
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nf_unregister_hooks(arpt_ops, ARRAY_SIZE(arpt_ops));
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unregister_pernet_subsys(&arptable_filter_net_ops);
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}
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module_init(arptable_filter_init);
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module_exit(arptable_filter_fini);
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