mirror of https://github.com/OISF/suricata
Philippe Antoine
3 years ago
committed by
Victor Julien
parent
f1f43cba5e
commit
461725a9bf
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DHCP keywords
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=============
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dhcp.leasetime
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--------------
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DHCP lease time (integer).
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Syntax::
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dhcp.leasetime:[op]<number>
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The version can be matched exactly, or compared using the _op_ setting::
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dhcp.leasetime:3 # exactly 3
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dhcp.leasetime:<3 # smaller than 3
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dhcp.leasetime:>=2 # greater or equal than 2
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Signature example::
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alert dhcp any any -> any any (msg:"small DHCP lease time (<3)"; dhcp.leasetime:<3; sid:1; rev:1;)
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@ -0,0 +1,34 @@
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/* Copyright (C) 2022 Open Information Security Foundation
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*
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* You can copy, redistribute or modify this Program under the terms of
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* the GNU General Public License version 2 as published by the Free
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* Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* version 2 along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*/
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use super::dhcp::{DHCPTransaction, DHCP_OPT_ADDRESS_TIME};
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use super::parser::DHCPOptionWrapper;
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#[no_mangle]
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pub unsafe extern "C" fn rs_dhcp_tx_get_leasetime(
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tx: &mut DHCPTransaction, leasetime: *mut u64,
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) -> u8 {
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for option in &tx.message.options {
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if option.code == DHCP_OPT_ADDRESS_TIME {
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if let DHCPOptionWrapper::TimeValue(ref time_value) = option.option {
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*leasetime = time_value.seconds as u64;
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return 1;
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}
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}
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}
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return 0;
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}
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@ -0,0 +1,130 @@
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/* Copyright (C) 2022 Open Information Security Foundation
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*
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* You can copy, redistribute or modify this Program under the terms of
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* the GNU General Public License leasetime 2 as published by the Free
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* Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* leasetime 2 along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*/
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#include "suricata-common.h"
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#include "rust.h"
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#include "detect-dhcp-leasetime.h"
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#include "detect-engine.h"
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#include "detect-engine-mpm.h"
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#include "detect-engine-prefilter.h"
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#include "detect-engine-uint.h"
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#include "detect-parse.h"
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static int g_buffer_id = 0;
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/**
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* \internal
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* \brief Function to match leasetime of a TX
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*
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* \param t Pointer to thread vars.
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* \param det_ctx Pointer to the pattern matcher thread.
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* \param f Pointer to the current flow.
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* \param flags Flags.
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* \param state App layer state.
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* \param s Pointer to the Signature.
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* \param m Pointer to the sigmatch that we will cast into
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* DetectU64Data.
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*
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* \retval 0 no match.
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* \retval 1 match.
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*/
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static int DetectDHCPLeaseTimeMatch(DetectEngineThreadCtx *det_ctx, Flow *f, uint8_t flags,
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void *state, void *txv, const Signature *s, const SigMatchCtx *ctx)
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{
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SCEnter();
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uint64_t leasetime;
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if (rs_dhcp_tx_get_leasetime(txv, &leasetime)) {
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const DetectU64Data *dd = (const DetectU64Data *)ctx;
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if (DetectU64Match(leasetime, dd)) {
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SCReturnInt(1);
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}
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}
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SCReturnInt(0);
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}
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/**
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* \internal
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* \brief Function to free memory associated with DetectU64Data.
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*
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* \param de_ptr Pointer to DetectU64Data.
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*/
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static void DetectDHCPLeaseTimeFree(DetectEngineCtx *de_ctx, void *ptr)
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{
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rs_detect_u64_free(ptr);
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}
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/**
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* \brief Function to add the parsed dhcp leasetime field into the current signature.
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*
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* \param de_ctx Pointer to the Detection Engine Context.
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* \param s Pointer to the Current Signature.
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* \param rawstr Pointer to the user provided flags options.
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* \param type Defines if this is notBefore or notAfter.
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*
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* \retval 0 on Success.
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* \retval -1 on Failure.
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*/
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static int DetectDHCPLeaseTimeSetup(DetectEngineCtx *de_ctx, Signature *s, const char *rawstr)
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{
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if (DetectSignatureSetAppProto(s, ALPROTO_DHCP) != 0)
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return -1;
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DetectU64Data *dd = DetectU64Parse(rawstr);
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if (dd == NULL) {
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SCLogError(SC_ERR_INVALID_ARGUMENT, "Parsing \'%s\' failed for %s", rawstr,
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sigmatch_table[DETECT_AL_DHCP_LEASETIME].name);
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return -1;
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}
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/* okay so far so good, lets get this into a SigMatch
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* and put it in the Signature. */
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SigMatch *sm = SigMatchAlloc();
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if (sm == NULL)
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goto error;
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sm->type = DETECT_AL_DHCP_LEASETIME;
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sm->ctx = (void *)dd;
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SigMatchAppendSMToList(s, sm, g_buffer_id);
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return 0;
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error:
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DetectDHCPLeaseTimeFree(de_ctx, dd);
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return -1;
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}
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/**
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* \brief Registration function for dhcp.procedure keyword.
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*/
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void DetectDHCPLeaseTimeRegister(void)
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{
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sigmatch_table[DETECT_AL_DHCP_LEASETIME].name = "dhcp.leasetime";
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sigmatch_table[DETECT_AL_DHCP_LEASETIME].desc = "match DHCP leasetime";
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sigmatch_table[DETECT_AL_DHCP_LEASETIME].url = "/rules/dhcp-keywords.html#dhcp-leasetime";
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sigmatch_table[DETECT_AL_DHCP_LEASETIME].AppLayerTxMatch = DetectDHCPLeaseTimeMatch;
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sigmatch_table[DETECT_AL_DHCP_LEASETIME].Setup = DetectDHCPLeaseTimeSetup;
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sigmatch_table[DETECT_AL_DHCP_LEASETIME].Free = DetectDHCPLeaseTimeFree;
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DetectAppLayerInspectEngineRegister2("dhcp.leasetime", ALPROTO_DHCP, SIG_FLAG_TOSERVER, 0,
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DetectEngineInspectGenericList, NULL);
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DetectAppLayerInspectEngineRegister2("dhcp.leasetime", ALPROTO_DHCP, SIG_FLAG_TOCLIENT, 0,
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DetectEngineInspectGenericList, NULL);
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g_buffer_id = DetectBufferTypeGetByName("dhcp.leasetime");
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}
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@ -0,0 +1,23 @@
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/* Copyright (C) 2022 Open Information Security Foundation
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*
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* You can copy, redistribute or modify this Program under the terms of
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* the GNU General Public License version 2 as published by the Free
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* Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* version 2 along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*/
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#ifndef __DETECT_DHCP_LEASETIME_H__
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#define __DETECT_DHCP_LEASETIME_H__
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void DetectDHCPLeaseTimeRegister(void);
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#endif /* __DETECT_DHCP_LEASETIME_H__ */
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