C++, windows, get the information on all network interfaces

sample.cpp

#include <winsock2.h>
#include <iphlpapi.h>
#include <stdio.h>
#include <stdlib.h>
#include <WS2tcpip.h>

// Link with Iphlpapi.lib
#pragma comment(lib, "IPHLPAPI.lib")



//////////////// all the code below should sit in a function, and could all be copy / pasted together into one

/* Declare and initialize variables */

	DWORD dwSize = 0;
	DWORD dwRetVal = 0;
	unsigned int i = 0;

	// only get IPv4 addresses
	ULONG flags = 0; // GAA_FLAG_SKIP_ANYCAST | GAA_FLAG_SKIP_MULTICAST | GAA_FLAG_SKIP_DNS_SERVER;
	ULONG family = AF_INET;

	LPVOID lpMsgBuf = NULL;

	PIP_ADAPTER_ADDRESSES pAddresses = NULL;
	ULONG outBufLen = 0;
	ULONG Iterations = 0;

	PIP_ADAPTER_ADDRESSES pCurrAddresses = NULL;
	PIP_ADAPTER_UNICAST_ADDRESS pUnicast = NULL;
	PIP_ADAPTER_ANYCAST_ADDRESS pAnycast = NULL;
	PIP_ADAPTER_MULTICAST_ADDRESS pMulticast = NULL;
	IP_ADAPTER_DNS_SERVER_ADDRESS* pDnServer = NULL;
	IP_ADAPTER_PREFIX* pPrefix = NULL;

	// for printing IPv4 addresses
	char buff[100];
	DWORD bufflen = 100;

	// allow the buffer to determine what length it needs to be ...
	dwRetVal = GetAdaptersAddresses(family, flags, NULL, NULL, &outBufLen);
	if (dwRetVal != ERROR_BUFFER_OVERFLOW)
	{
		Logger->Error("Failed to get length of the AdapterAddresses. Cannot retrieve IPv4 address. Err code: " + to_string(dwRetVal));
	}

	pAddresses = (PIP_ADAPTER_ADDRESSES)malloc(outBufLen);

	// ... and then get the adapter addresses
	dwRetVal = GetAdaptersAddresses(family, flags, NULL, pAddresses, &outBufLen);

	if (dwRetVal == NO_ERROR) {
		// If successful, output some information from the data we received
		pCurrAddresses = pAddresses;
		while (pCurrAddresses) {
			printf("\tLength of the IP_ADAPTER_ADDRESS struct: %ld\n",
				pCurrAddresses->Length);
			printf("\tIfIndex (IPv4 interface): %u\n", pCurrAddresses->IfIndex);
			printf("\tAdapter name: %s\n", pCurrAddresses->AdapterName);

			pUnicast = pCurrAddresses->FirstUnicastAddress;
			if (pUnicast != NULL) {
				for (i = 0; pUnicast != NULL; i++)
				{
					sockaddr_in* sa_in = (sockaddr_in*)pUnicast->Address.lpSockaddr;
					printf("\tIPV4: %s\n", inet_ntop(AF_INET, &(sa_in->sin_addr), buff, bufflen));
					pUnicast = pUnicast->Next;
				}

				//printf("\tNumber of Unicast Addresses: %d\n", i);
			}
			else
				printf("\tNo Unicast Addresses\n");

			pAnycast = pCurrAddresses->FirstAnycastAddress;
			if (pAnycast) {
				/*for (i = 0; pAnycast != NULL; i++)
					pAnycast = pAnycast->Next;*/

				for (i = 0; pAnycast != NULL; i++)
				{
					sockaddr_in* sa_in = (sockaddr_in*)pAnycast->Address.lpSockaddr;
					printf("\tAnycast: %s\n", inet_ntop(AF_INET, &(sa_in->sin_addr), buff, bufflen));
					pAnycast = pAnycast->Next;
				}

				//printf("\tNumber of Anycast Addresses: %d\n", i);
			}
			else
				printf("\tNo Anycast Addresses\n");

			pMulticast = pCurrAddresses->FirstMulticastAddress;
			if (pMulticast) {
				/*for (i = 0; pMulticast != NULL; i++)
					pMulticast = pMulticast->Next;*/

				for (i = 0; pMulticast != NULL; i++)
				{
					sockaddr_in* sa_in = (sockaddr_in*)pMulticast->Address.lpSockaddr;
					printf("\tmulticast: %s\n", inet_ntop(AF_INET, &(sa_in->sin_addr), buff, bufflen));
					pMulticast = pMulticast->Next;
				}

				//printf("\tNumber of Multicast Addresses: %d\n", i);
			}
			else
				printf("\tNo Multicast Addresses\n");

			pDnServer = pCurrAddresses->FirstDnsServerAddress;
			if (pDnServer) {
				/*for (i = 0; pDnServer != NULL; i++)
					pDnServer = pDnServer->Next;*/
				
				for (i = 0; pDnServer != NULL; i++)
				{
					sockaddr_in* sa_in = (sockaddr_in*)pDnServer->Address.lpSockaddr;
					printf("\tDNS server: %s\n", inet_ntop(AF_INET, &(sa_in->sin_addr), buff, bufflen));
					pDnServer = pDnServer->Next;
				}

				//printf("\tNumber of DNS Server Addresses: %d\n", i);
			}
			else
				printf("\tNo DNS Server Addresses\n");

			printf("\tDNS Suffix: %wS\n", pCurrAddresses->DnsSuffix);
			printf("\tDescription: %wS\n", pCurrAddresses->Description);
			printf("\tFriendly name: %wS\n", pCurrAddresses->FriendlyName);

			if (pCurrAddresses->PhysicalAddressLength != 0) {
				printf("\tPhysical address: ");
				for (i = 0; i < (int)pCurrAddresses->PhysicalAddressLength;
					i++) {
					if (i == (pCurrAddresses->PhysicalAddressLength - 1))
						printf("%.2X\n",
						(int)pCurrAddresses->PhysicalAddress[i]);
					else
						printf("%.2X-",
						(int)pCurrAddresses->PhysicalAddress[i]);
				}
			}
			printf("\tFlags: %ld\n", pCurrAddresses->Flags);
			printf("\tMtu: %lu\n", pCurrAddresses->Mtu);
			printf("\tIfType: %ld\n", pCurrAddresses->IfType);
			printf("\tOperStatus: %ld\n", pCurrAddresses->OperStatus);
			printf("\tIpv6IfIndex (IPv6 interface): %u\n",
				pCurrAddresses->Ipv6IfIndex);
			printf("\tZoneIndices (hex): ");
			for (i = 0; i < 16; i++)
				printf("%lx ", pCurrAddresses->ZoneIndices[i]);
			printf("\n");

			printf("\tTransmit link speed: %I64u\n", pCurrAddresses->TransmitLinkSpeed);
			printf("\tReceive link speed: %I64u\n", pCurrAddresses->ReceiveLinkSpeed);

			pPrefix = pCurrAddresses->FirstPrefix;
			if (pPrefix) {
				for (i = 0; pPrefix != NULL; i++)
					pPrefix = pPrefix->Next;
				printf("\tNumber of IP Adapter Prefix entries: %d\n", i);
			}
			else
				printf("\tNumber of IP Adapter Prefix entries: 0\n");

			printf("\n");

			pCurrAddresses = pCurrAddresses->Next;
		}
	}
	else {
		printf("Call to GetAdaptersAddresses failed with error: %d\n",
			dwRetVal);
		if (dwRetVal == ERROR_NO_DATA)
			printf("\tNo addresses were found for the requested parameters\n");
		else {

			if (FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER |
				FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
				NULL, dwRetVal, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),
				// Default language
				(LPTSTR)&lpMsgBuf, 0, NULL)) {
				printf("\tError: %s", lpMsgBuf);
				LocalFree(lpMsgBuf);
				if (pAddresses)
					free(pAddresses);
			}
		}
	}

	if (pAddresses) {
		free(pAddresses);
	}