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- // 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);
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