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