bridge/netfilter/ebtable_nat.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  *  ebtable_nat
0004  *
0005  *  Authors:
0006  *  Bart De Schuymer <bdschuym@pandora.be>
0007  *
0008  *  April, 2002
0009  *
0010  */
0011
0012 #include <linux/netfilter_bridge/ebtables.h>
0013 #include <uapi/linux/netfilter_bridge.h>
0014 #include <linux/module.h>
0015
0016 #define NAT_VALID_HOOKS ((1 << NF_BR_PRE_ROUTING) | (1 << NF_BR_LOCAL_OUT) | \
0017              (1 << NF_BR_POST_ROUTING))
0018
0019 static struct ebt_entries initial_chains[] = {
0020     {
0021         .name   = "PREROUTING",
0022         .policy = EBT_ACCEPT,
0023     },
0024     {
0025         .name   = "OUTPUT",
0026         .policy = EBT_ACCEPT,
0027     },
0028     {
0029         .name   = "POSTROUTING",
0030         .policy = EBT_ACCEPT,
0031     }
0032 };
0033
0034 static struct ebt_replace_kernel initial_table = {
0035     .name       = "nat",
0036     .valid_hooks    = NAT_VALID_HOOKS,
0037     .entries_size   = 3 * sizeof(struct ebt_entries),
0038     .hook_entry = {
0039         [NF_BR_PRE_ROUTING] = &initial_chains[0],
0040         [NF_BR_LOCAL_OUT]   = &initial_chains[1],
0041         [NF_BR_POST_ROUTING]    = &initial_chains[2],
0042     },
0043     .entries    = (char *)initial_chains,
0044 };
0045
0046 static const struct ebt_table frame_nat = {
0047     .name       = "nat",
0048     .table      = &initial_table,
0049     .valid_hooks    = NAT_VALID_HOOKS,
0050     .me     = THIS_MODULE,
0051 };
0052
0053 static const struct nf_hook_ops ebt_ops_nat[] = {
0054     {
0055         .hook       = ebt_do_table,
0056         .pf     = NFPROTO_BRIDGE,
0057         .hooknum    = NF_BR_LOCAL_OUT,
0058         .priority   = NF_BR_PRI_NAT_DST_OTHER,
0059     },
0060     {
0061         .hook       = ebt_do_table,
0062         .pf     = NFPROTO_BRIDGE,
0063         .hooknum    = NF_BR_POST_ROUTING,
0064         .priority   = NF_BR_PRI_NAT_SRC,
0065     },
0066     {
0067         .hook       = ebt_do_table,
0068         .pf     = NFPROTO_BRIDGE,
0069         .hooknum    = NF_BR_PRE_ROUTING,
0070         .priority   = NF_BR_PRI_NAT_DST_BRIDGED,
0071     },
0072 };
0073
0074 static int frame_nat_table_init(struct net *net)
0075 {
0076     return ebt_register_table(net, &frame_nat, ebt_ops_nat);
0077 }
0078
0079 static void __net_exit frame_nat_net_pre_exit(struct net *net)
0080 {
0081     ebt_unregister_table_pre_exit(net, "nat");
0082 }
0083
0084 static void __net_exit frame_nat_net_exit(struct net *net)
0085 {
0086     ebt_unregister_table(net, "nat");
0087 }
0088
0089 static struct pernet_operations frame_nat_net_ops = {
0090     .exit = frame_nat_net_exit,
0091     .pre_exit = frame_nat_net_pre_exit,
0092 };
0093
0094 static int __init ebtable_nat_init(void)
0095 {
0096     int ret = ebt_register_template(&frame_nat, frame_nat_table_init);
0097
0098     if (ret)
0099         return ret;
0100
0101     ret = register_pernet_subsys(&frame_nat_net_ops);
0102     if (ret) {
0103         ebt_unregister_template(&frame_nat);
0104         return ret;
0105     }
0106
0107     return ret;
0108 }
0109
0110 static void __exit ebtable_nat_fini(void)
0111 {
0112     unregister_pernet_subsys(&frame_nat_net_ops);
0113     ebt_unregister_template(&frame_nat);
0114 }
0115
0116 module_init(ebtable_nat_init);
0117 module_exit(ebtable_nat_fini);
0118 MODULE_LICENSE("GPL");