第三种方法－ 使用SNMP扩展API
我要讨论的第三种方法是使用Windows的SNMP(简单网络管理协议)扩展来取得MAC地址。在我的经验里，这个协议很简单。代码也是直勾勾的向前的。基本步骤和Netbios相同：
1》取得网卡列表
2》查询每块卡的类型和MAC地址
3》保存当前网卡
我个人对SNMP了解不多，但如我刚刚所言，代码十分清楚。
snmp.cpp
#include <snmp.h>
#include <conio.h>
#include <stdio.h>
typedef bool(WINAPI * pSnmpExtensionInit) (
IN DWORD dwTimeZeroReference,
OUT HANDLE * hPollForTrapEvent,
OUT AsnObjectIdentifier * supportedView);
typedef bool(WINAPI * pSnmpExtensionTrap) (
OUT AsnObjectIdentifier * enterprise,
OUT AsnInteger * genericTrap,
OUT AsnInteger * specificTrap,
OUT AsnTimeticks * timeStamp,
OUT RFC1157VarBindList * variableBindings);
typedef bool(WINAPI * pSnmpExtensionQuery) (
IN BYTE requestType,
IN OUT RFC1157VarBindList * variableBindings,
OUT AsnInteger * errorStatus,
OUT AsnInteger * errorIndex);
typedef bool(WINAPI * pSnmpExtensionInitEx) (
OUT AsnObjectIdentifier * supportedView);
void main()
{
HINSTANCE m_hInst;
pSnmpExtensionInit m_Init;
pSnmpExtensionInitEx m_InitEx;
pSnmpExtensionQuery m_Query;
pSnmpExtensionTrap m_Trap;
HANDLE PollForTrapEvent;
AsnObjectIdentifier SupportedView;
UINT OID_ifEntryType[] = {1, 3, 6, 1, 2, 1, 2, 2, 1, 3};
UINT OID_ifEntryNum[] = {1, 3, 6, 1, 2, 1, 2, 1};
UINT OID_ipMACEntAddr[] = {1, 3, 6, 1, 2, 1, 2, 2, 1, 6};
AsnObjectIdentifier MIB_ifMACEntAddr =
{ sizeof(OID_ipMACEntAddr) sizeof(UINT), OID_ipMACEntAddr };
AsnObjectIdentifier MIB_ifEntryType =
{sizeof(OID_ifEntryType) sizeof(UINT), OID_ifEntryType};
AsnObjectIdentifier MIB_ifEntryNum =
{sizeof(OID_ifEntryNum) sizeof(UINT), OID_ifEntryNum};
RFC1157VarBindList varBindList;
RFC1157VarBind varBind[2];
AsnInteger errorStatus;
AsnInteger errorIndex;
AsnObjectIdentifier MIB_NULL = {0, 0};
int ret;
int dtmp;
int i = 0, j = 0;
bool found = false;
char TempEthernet[13];
m_Init = NULL;
m_InitEx = NULL;
m_Query = NULL;
m_Trap = NULL;
/* 载入SNMP DLL并取得实例句柄 */
m_hInst = LoadLibrary("inetmib1.dll");
if (m_hInst < (HINSTANCE) HINSTANCE_ERROR)
{
m_hInst = NULL;
return;
}
m_Init =
(pSnmpExtensionInit) GetProcAddress(m_hInst, "SnmpExtensionInit");
m_InitEx =
(pSnmpExtensionInitEx) GetProcAddress(m_hInst,
"SnmpExtensionInitEx");
m_Query =
(pSnmpExtensionQuery) GetProcAddress(m_hInst,
"SnmpExtensionQuery");
m_Trap =
(pSnmpExtensionTrap) GetProcAddress(m_hInst, "SnmpExtensionTrap");
m_Init(GetTickCount(), &PollForTrapEvent, &SupportedView);
/* 初始化用来接收m_Query查询结果的变量列表 */
varBindList.list = varBind;
varBind[0].name = MIB_NULL;
varBind[1].name = MIB_NULL;
/* 在OID中拷贝并查找接口表中的入口数量 */
varBindList.len = 1; /* Only retrieving one item */
SNMP_oidcpy(&varBind[0].name, &MIB_ifEntryNum);
ret =
m_Query(ASN_RFC1157_GETNEXTREQUEST, &varBindList, &errorStatus,
&errorIndex);
printf("# of adapters in this system : %in",
varBind[0].value.asnValue.number);
varBindList.len = 2;
/* 拷贝OID的ifType－接口类型 */
SNMP_oidcpy(&varBind[0].name, &MIB_ifEntryType);
/* 拷贝OID的ifPhysAddress－物理地址 */
SNMP_oidcpy(&varBind[1].name, &MIB_ifMACEntAddr);
do
{
/* 提交查询，结果将载入 varBindList。
可以预料这个循环调用的次数和系统中的接口卡数量相等 */
ret =
m_Query(ASN_RFC1157_GETNEXTREQUEST, &varBindList, &errorStatus,
&errorIndex);
if (!ret)
ret = 1;
else
/* 确认正确的返回类型 */
ret =
SNMP_oidncmp(&varBind[0].name, &MIB_ifEntryType,
MIB_ifEntryType.idLength); if (!ret) {
j++;
dtmp = varBind[0].value.asnValue.number;
printf("Interface #%i type : %in", j, dtmp);
/* Type 6 describes ethernet interfaces */
if (dtmp == 6)
{
/* 确认我们已经在此取得地址 */
ret =
SNMP_oidncmp(&varBind[1].name, &MIB_ifMACEntAddr,
MIB_ifMACEntAddr.idLength);
if ((!ret) && (varBind[1].value.asnValue.address.stream != NULL))
{
if((varBind[1].value.asnValue.address.stream[0] == 0x44)
&& (varBind[1].value.asnValue.address.stream[1] == 0x45)
&& (varBind[1].value.asnValue.address.stream[2] == 0x53)
&& (varBind[1].value.asnValue.address.stream[3] == 0x54)
&& (varBind[1].value.asnValue.address.stream[4] == 0x00))
{
/* 忽略所有的拨号网络接口卡 */
printf("Interface #%i is a DUN adaptern", j);
continue;
}
if ((varBind[1].value.asnValue.address.stream[0] == 0x00)
&& (varBind[1].value.asnValue.address.stream[1] == 0x00)
&& (varBind[1].value.asnValue.address.stream[2] == 0x00)
&& (varBind[1].value.asnValue.address.stream[3] == 0x00)
&& (varBind[1].value.asnValue.address.stream[4] == 0x00)
&& (varBind[1].value.asnValue.address.stream[5] == 0x00))
{
/* 忽略由其他的网络接口卡返回的NULL地址 */
printf("Interface #%i is a NULL addressn", j);
continue;
}
sprintf(TempEthernet, "%02x%02x%02x%02x%02x%02x",
varBind[1].value.asnValue.address.stream[0],
varBind[1].value.asnValue.address.stream[1],
varBind[1].value.asnValue.address.stream[2],
varBind[1].value.asnValue.address.stream[3],
varBind[1].value.asnValue.address.stream[4],
varBind[1].value.asnValue.address.stream[5]);
printf("MAC Address of interface #%i: %sn", j,
TempEthernet);}
}
}
} while (!ret); /* 发生错误终止。 */
getch();
FreeLibrary(m_hInst);
/* 解除绑定 */
SNMP_FreeVarBind(&varBind[0]);
SNMP_FreeVarBind(&varBind[1]);
}
