Get network interface name from IPv4 address

Question

Given an IPv4 address, how can I obtain its associated network interface name, like "Ethernet adapter Local Area Connection", in Windows using C++? Alternately, how can I obtain a list of both network interface names and IPv4 addresses for the local computer? I'm able to get only the IPv4 addresses using getaddrinfo and inet_ntoa.

Kerwon

It depend on platform. For example, you should use GetAdaptersInfo on windows. – Swat

@Swat The documentation for GetAdaptersInfo says to use GetAdaptersAddresses on XP and later. Is this preferred? – Ruysdael

Yes, better to use GetAdaptersAddresses if you want make it works on XP or later. – Swat

This seems work gist.github.com/yoggy/1241986 – Swat

Answer 1

#include <windows.h>
#include <iphlpapi.h>
#include <stdio.h>

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

int
main(int argc, char** argv) {
  PIP_ADAPTER_INFO pAdapterInfo;
  pAdapterInfo = (IP_ADAPTER_INFO *) malloc(sizeof(IP_ADAPTER_INFO));
  ULONG buflen = sizeof(IP_ADAPTER_INFO);

  if(GetAdaptersInfo(pAdapterInfo, &buflen) == ERROR_BUFFER_OVERFLOW) {
    free(pAdapterInfo);
    pAdapterInfo = (IP_ADAPTER_INFO *) malloc(buflen);
  }

  if(GetAdaptersInfo(pAdapterInfo, &buflen) == NO_ERROR) {
    PIP_ADAPTER_INFO pAdapter = pAdapterInfo;
    while (pAdapter) {
      printf("\tAdapter Name: \t%s\n", pAdapter->AdapterName);
      printf("\tAdapter Desc: \t%s\n", pAdapter->Description);
      printf("\tAdapter Addr: \t%ld\n", pAdapter->Address);
      printf("\tIP Address: \t%s\n", pAdapter->IpAddressList.IpAddress.String);
      printf("\tIP Mask: \t%s\n", pAdapter->IpAddressList.IpMask.String);
      printf("\tGateway: \t%s\n", pAdapter->GatewayList.IpAddress.String);
      if(pAdapter->DhcpEnabled) {
        printf("\tDHCP Enabled: Yes\n");
        printf("\t\tDHCP Server: \t%s\n", pAdapter->DhcpServer.IpAddress.String);
        printf("\tLease Obtained: %ld\n", pAdapter->LeaseObtained);
      } else {
        printf("\tDHCP Enabled: No\n");
      }
      if(pAdapter->HaveWins) {
        printf("\tHave Wins: Yes\n");
        printf("\t\tPrimary Wins Server: \t%s\n", pAdapter->PrimaryWinsServer.IpAddress.String);
        printf("\t\tSecondary Wins Server: \t%s\n", pAdapter->SecondaryWinsServer.IpAddress.String);
      } else {
        printf("\tHave Wins: No\n");
      }
      pAdapter = pAdapter->Next;
    }
  } else {
    printf("Call to GetAdaptersInfo failed.\n");
  }
}

As @sonyisda1 mentioned, this is taken from MSDN.

Swat

Probably should be mentioned this is taken from MSDN and if using WinXP or later GetAdaptersAddresses should be used instead – Jeffcott

Answer 2

I'll share my minimal version as well:

#include <windows.h>
#include <iphlpapi.h>
#include <stdio.h>

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

int main() {
    ULONG buflen = sizeof(IP_ADAPTER_INFO);
    IP_ADAPTER_INFO *pAdapterInfo = (IP_ADAPTER_INFO *)malloc(buflen);

    if (GetAdaptersInfo(pAdapterInfo, &buflen) == ERROR_BUFFER_OVERFLOW) {
        free(pAdapterInfo);
        pAdapterInfo = (IP_ADAPTER_INFO *)malloc(buflen);
    }

    if (GetAdaptersInfo(pAdapterInfo, &buflen) == NO_ERROR) {
        for (IP_ADAPTER_INFO *pAdapter = pAdapterInfo; pAdapter; pAdapter = pAdapter->Next) {
            printf("%s (%s)\n", pAdapter->IpAddressList.IpAddress.String, pAdapter->Description);
        }
    }

    if (pAdapterInfo) free(pAdapterInfo);
    return 0;
}

Kerwon

This is helpful – Dalessio