forked from chunyexixiaoyu/xiuos
137 lines
3.9 KiB
C
137 lines
3.9 KiB
C
/**
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* @file
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* Additional SNMPv3 functionality RFC3414 and RFC3826.
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*/
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/*
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* Copyright (c) 2016 Elias Oenal.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without modification,
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* are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
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* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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* OF SUCH DAMAGE.
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*
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* Author: Elias Oenal <lwip@eliasoenal.com>
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*/
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#include "snmpv3_priv.h"
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#include "lwip/apps/snmpv3.h"
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#include "lwip/sys.h"
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#include <string.h>
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#if LWIP_SNMP && LWIP_SNMP_V3
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#ifdef LWIP_SNMPV3_INCLUDE_ENGINE
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#include LWIP_SNMPV3_INCLUDE_ENGINE
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#endif
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#define SNMP_MAX_TIME_BOOT 2147483647UL
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/** Call this if engine has been changed. Has to reset boots, see below */
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void
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snmpv3_engine_id_changed(void)
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{
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snmpv3_set_engine_boots(0);
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}
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/** According to RFC3414 2.2.2.
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*
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* The number of times that the SNMP engine has
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* (re-)initialized itself since snmpEngineID
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* was last configured.
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*/
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s32_t
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snmpv3_get_engine_boots_internal(void)
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{
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if (snmpv3_get_engine_boots() == 0 ||
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snmpv3_get_engine_boots() < SNMP_MAX_TIME_BOOT) {
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return snmpv3_get_engine_boots();
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}
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snmpv3_set_engine_boots(SNMP_MAX_TIME_BOOT);
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return snmpv3_get_engine_boots();
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}
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/** RFC3414 2.2.2.
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*
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* Once the timer reaches 2147483647 it gets reset to zero and the
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* engine boot ups get incremented.
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*/
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s32_t
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snmpv3_get_engine_time_internal(void)
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{
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if (snmpv3_get_engine_time() >= SNMP_MAX_TIME_BOOT) {
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snmpv3_reset_engine_time();
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if (snmpv3_get_engine_boots() < SNMP_MAX_TIME_BOOT - 1) {
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snmpv3_set_engine_boots(snmpv3_get_engine_boots() + 1);
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} else {
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snmpv3_set_engine_boots(SNMP_MAX_TIME_BOOT);
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}
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}
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return snmpv3_get_engine_time();
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}
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#if LWIP_SNMP_V3_CRYPTO
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/* This function ignores the byte order suggestion in RFC3414
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* since it simply doesn't influence the effectiveness of an IV.
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*
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* Implementing RFC3826 priv param algorithm if LWIP_RAND is available.
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*
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* @todo: This is a potential thread safety issue.
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*/
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err_t
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snmpv3_build_priv_param(u8_t *priv_param)
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{
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#ifdef LWIP_RAND /* Based on RFC3826 */
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static u8_t init;
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static u32_t priv1, priv2;
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/* Lazy initialisation */
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if (init == 0) {
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init = 1;
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priv1 = LWIP_RAND();
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priv2 = LWIP_RAND();
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}
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SMEMCPY(&priv_param[0], &priv1, sizeof(priv1));
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SMEMCPY(&priv_param[4], &priv2, sizeof(priv2));
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/* Emulate 64bit increment */
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priv1++;
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if (!priv1) { /* Overflow */
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priv2++;
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}
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#else /* Based on RFC3414 */
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static u32_t ctr;
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u32_t boots = snmpv3_get_engine_boots_internal();
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SMEMCPY(&priv_param[0], &boots, 4);
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SMEMCPY(&priv_param[4], &ctr, 4);
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ctr++;
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#endif
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return ERR_OK;
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}
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#endif /* LWIP_SNMP_V3_CRYPTO */
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#endif
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