vc枚举本机端口信息

关于查看本机端口信息，可能大多数人都知道在cmd下的netstat 命令，殊不知该命令在底层也是调用相关api来实现的，
相关函数有：
GetTcpTable
GetExtendedTcpTable
GetUdpTable
GetExtendedUdpTable
这些函数就可以获取相关tcp、udp端口以及相关进程的信息。而且这些函数都是从Iphlpapi.dll里导出的。
函数的相关用法可查询msdn在掌握，下面封装一段代码，来枚举每机的所有监听端口

#include "stdafx.h"
#include <winsock2.h>
#include <ws2tcpip.h>
#include <iphlpapi.h>
#include <stdio.h>
#include <Windows.h>
#include <list>

#pragma comment(lib, "iphlpapi.lib")
#pragma comment(lib, "ws2_32.lib")

using namespace std;

#define MALLOC(x) HeapAlloc(GetProcessHeap(), 0, (x))
#define FREE(x) HeapFree(GetProcessHeap(), 0, (x))

BOOL GetLocalListeningPort(list<WORD> & listPort);

int _tmain(int argc, _TCHAR* argv[])
{
	list<WORD> portArray;

	GetLocalListeningPort(portArray);

	for (list<WORD>::iterator it = portArray.begin(); it != portArray.end(); it++)
	{
		WORD port = *it;
		printf("listenPort:%d
", port);
	}
	return 0;
}

BOOL GetLocalListeningPort(list<WORD> & listPort)
{
	PMIB_TCPTABLE pTcpTable;
	DWORD dwSize = 0;
	DWORD dwRetVal = 0;
	BOOL bRet = FALSE;
	char szLocalAddr[128];
	char szBuf[128] = { 0 };
	pTcpTable = (PMIB_TCPTABLE)szBuf;
	dwSize = 128 * sizeof(char);

	struct in_addr IpAddr;

	int i;

	if ((dwRetVal = GetTcpTable(pTcpTable, &dwSize, TRUE)) == ERROR_INSUFFICIENT_BUFFER)
	{
		pTcpTable = (MIB_TCPTABLE *)MALLOC(dwSize);
		if (pTcpTable == NULL) {
			printf("Error allocating memory
");
			return bRet;
		}
	}

	if ((dwRetVal = GetTcpTable(pTcpTable, &dwSize, TRUE)) == NO_ERROR)
	{
		printf("Number of entries: %d
", pTcpTable->dwNumEntries);
		for (i = 0; i < (int)pTcpTable->dwNumEntries; i++)
		{
			IpAddr.S_un.S_addr = (u_long)pTcpTable->table[i].dwLocalAddr;
			strcpy_s(szLocalAddr, sizeof (szLocalAddr), inet_ntoa(IpAddr));
			printf("local info: %s:%d 	", szLocalAddr, ntohs((u_short)pTcpTable->table[i].dwLocalPort));
			printf(" TCP[%d] State: %ld - ", i, pTcpTable->table[i].dwState);

			switch (pTcpTable->table[i].dwState)
			{
			case MIB_TCP_STATE_CLOSED:
				printf("CLOSED 
");
				break;
			case MIB_TCP_STATE_LISTEN:
				listPort.push_back(ntohs((u_short)pTcpTable->table[i].dwLocalPort));
				printf("LISTEN 
");
				break;
			case MIB_TCP_STATE_SYN_SENT:
				printf("SYN-SENT 
");
				break;
			case MIB_TCP_STATE_SYN_RCVD:
				printf("SYN-RECEIVED 
");
				break;
			case MIB_TCP_STATE_ESTAB:
				printf("ESTABLISHED 
");
				break;
			case MIB_TCP_STATE_FIN_WAIT1:
				printf("FIN-WAIT-1 
");
				break;
			case MIB_TCP_STATE_FIN_WAIT2:
				printf("FIN-WAIT-2 
");
				break;
			case MIB_TCP_STATE_CLOSE_WAIT:
				printf("CLOSE-WAIT 
");
				break;
			case MIB_TCP_STATE_CLOSING:
				printf("CLOSING 
");
				break;
			case MIB_TCP_STATE_LAST_ACK:
				printf("LAST-ACK 
");
				break;
			case MIB_TCP_STATE_TIME_WAIT:
				printf("TIME-WAIT 
");
				break;
			case MIB_TCP_STATE_DELETE_TCB:
				printf("DELETE-TCB 
");
				break;
			default:
				printf("UNKNOWN dwState value 
");
				break;
			}
		}
	}
	else
	{
		printf("GetTcpTable failed with %d 
", dwRetVal);
		goto EXIT;
	}

	bRet = TRUE;
EXIT:

	if (pTcpTable != (PMIB_TCPTABLE)szBuf)
	{
		FREE(pTcpTable);
		pTcpTable = NULL;
	}
	
	return bRet;
}