1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * This is the 1999 rewrite of IP Firewalling, aiming for kernel 2.3.x. 4 * 5 * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling 6 * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org> 7 */ 8 9 #include <linux/module.h> 10 #include <linux/moduleparam.h> 11 #include <linux/netfilter_ipv6/ip6_tables.h> 12 #include <linux/slab.h> 13 14 MODULE_LICENSE("GPL"); 15 MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>"); 16 MODULE_DESCRIPTION("ip6tables filter table"); 17 18 #define FILTER_VALID_HOOKS ((1 << NF_INET_LOCAL_IN) | \ 19 (1 << NF_INET_FORWARD) | \ 20 (1 << NF_INET_LOCAL_OUT)) 21 22 static int __net_init ip6table_filter_table_init(struct net *net); 23 24 static const struct xt_table packet_filter = { 25 .name = "filter", 26 .valid_hooks = FILTER_VALID_HOOKS, 27 .me = THIS_MODULE, 28 .af = NFPROTO_IPV6, 29 .priority = NF_IP6_PRI_FILTER, 30 .table_init = ip6table_filter_table_init, 31 }; 32 33 /* The work comes in here from netfilter.c. */ 34 static unsigned int 35 ip6table_filter_hook(void *priv, struct sk_buff *skb, 36 const struct nf_hook_state *state) 37 { 38 return ip6t_do_table(skb, state, state->net->ipv6.ip6table_filter); 39 } 40 41 static struct nf_hook_ops *filter_ops __read_mostly; 42 43 /* Default to forward because I got too much mail already. */ 44 static bool forward = true; 45 module_param(forward, bool, 0000); 46 47 static int __net_init ip6table_filter_table_init(struct net *net) 48 { 49 struct ip6t_replace *repl; 50 int err; 51 52 if (net->ipv6.ip6table_filter) 53 return 0; 54 55 repl = ip6t_alloc_initial_table(&packet_filter); 56 if (repl == NULL) 57 return -ENOMEM; 58 /* Entry 1 is the FORWARD hook */ 59 ((struct ip6t_standard *)repl->entries)[1].target.verdict = 60 forward ? -NF_ACCEPT - 1 : -NF_DROP - 1; 61 62 err = ip6t_register_table(net, &packet_filter, repl, filter_ops, 63 &net->ipv6.ip6table_filter); 64 kfree(repl); 65 return err; 66 } 67 68 static int __net_init ip6table_filter_net_init(struct net *net) 69 { 70 if (net == &init_net || !forward) 71 return ip6table_filter_table_init(net); 72 73 return 0; 74 } 75 76 static void __net_exit ip6table_filter_net_pre_exit(struct net *net) 77 { 78 if (net->ipv6.ip6table_filter) 79 ip6t_unregister_table_pre_exit(net, net->ipv6.ip6table_filter, 80 filter_ops); 81 } 82 83 static void __net_exit ip6table_filter_net_exit(struct net *net) 84 { 85 if (!net->ipv6.ip6table_filter) 86 return; 87 ip6t_unregister_table_exit(net, net->ipv6.ip6table_filter); 88 net->ipv6.ip6table_filter = NULL; 89 } 90 91 static struct pernet_operations ip6table_filter_net_ops = { 92 .init = ip6table_filter_net_init, 93 .pre_exit = ip6table_filter_net_pre_exit, 94 .exit = ip6table_filter_net_exit, 95 }; 96 97 static int __init ip6table_filter_init(void) 98 { 99 int ret; 100 101 filter_ops = xt_hook_ops_alloc(&packet_filter, ip6table_filter_hook); 102 if (IS_ERR(filter_ops)) 103 return PTR_ERR(filter_ops); 104 105 ret = register_pernet_subsys(&ip6table_filter_net_ops); 106 if (ret < 0) 107 kfree(filter_ops); 108 109 return ret; 110 } 111 112 static void __exit ip6table_filter_fini(void) 113 { 114 unregister_pernet_subsys(&ip6table_filter_net_ops); 115 kfree(filter_ops); 116 } 117 118 module_init(ip6table_filter_init); 119 module_exit(ip6table_filter_fini); 120