| // SPDX-License-Identifier: GPL-2.0-only |
| /* (C) 2001-2002 Magnus Boden <mb@ozaba.mine.nu> |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/udp.h> |
| |
| #include <net/netfilter/nf_conntrack_helper.h> |
| #include <net/netfilter/nf_conntrack_expect.h> |
| #include <net/netfilter/nf_nat_helper.h> |
| #include <linux/netfilter/nf_conntrack_tftp.h> |
| |
| #define NAT_HELPER_NAME "tftp" |
| |
| MODULE_AUTHOR("Magnus Boden <mb@ozaba.mine.nu>"); |
| MODULE_DESCRIPTION("TFTP NAT helper"); |
| MODULE_LICENSE("GPL"); |
| MODULE_ALIAS_NF_NAT_HELPER(NAT_HELPER_NAME); |
| |
| static struct nf_conntrack_nat_helper nat_helper_tftp = |
| NF_CT_NAT_HELPER_INIT(NAT_HELPER_NAME); |
| |
| static unsigned int help(struct sk_buff *skb, |
| enum ip_conntrack_info ctinfo, |
| struct nf_conntrack_expect *exp) |
| { |
| const struct nf_conn *ct = exp->master; |
| |
| exp->saved_proto.udp.port |
| = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.udp.port; |
| exp->dir = IP_CT_DIR_REPLY; |
| exp->expectfn = nf_nat_follow_master; |
| if (nf_ct_expect_related(exp, 0) != 0) { |
| nf_ct_helper_log(skb, exp->master, "cannot add expectation"); |
| return NF_DROP; |
| } |
| return NF_ACCEPT; |
| } |
| |
| static void __exit nf_nat_tftp_fini(void) |
| { |
| nf_nat_helper_unregister(&nat_helper_tftp); |
| RCU_INIT_POINTER(nf_nat_tftp_hook, NULL); |
| synchronize_rcu(); |
| } |
| |
| static int __init nf_nat_tftp_init(void) |
| { |
| BUG_ON(nf_nat_tftp_hook != NULL); |
| nf_nat_helper_register(&nat_helper_tftp); |
| RCU_INIT_POINTER(nf_nat_tftp_hook, help); |
| return 0; |
| } |
| |
| module_init(nf_nat_tftp_init); |
| module_exit(nf_nat_tftp_fini); |