< DHCP Renew & Release | IP Helper Functions Main | GetAdaptersInfo & GetAdaptersAddresses Examples >
IP Helper Functions 13 Part 8
What do we have in this chapter 13 part 8?
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Program Example Using GetIpAddrTable() Function
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Program Example Using AddIPAddress() Function
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Program Example Using GetIpAddrTable() Function
The GetIpAddrTable() function retrieves the interface–to–IPv4 address mapping table. Create a new empty Win32 console mode application and add the project/solution name.
Add the following code. |
// Description: This example retrieves the IP address table,
// then prints some members of the IP address entries in the table
//
// Link to ws2_32.lib
#include <winsock2.h>
#include <ws2tcpip.h>
// Link to Iphlpapi.lib
#include <iphlpapi.h>
#include <stdio.h>
// Note: could also use malloc() and free()
#define MALLOC(x) HeapAlloc(GetProcessHeap(), 0, (x))
#define FREE(x) HeapFree(GetProcessHeap(), 0, (x))
int main()
{
int i;
// Variables used by GetIpAddrTable
PMIB_IPADDRTABLE pIPAddrTable;
DWORD dwSize = 0;
DWORD dwRetVal = 0;
IN_ADDR IPAddr;
// Variables used to return error message
LPVOID lpMsgBuf;
// Before calling AddIPAddress we use GetIpAddrTable to get
// an adapter to which we can add the IP.
pIPAddrTable = (MIB_IPADDRTABLE *) MALLOC(sizeof (MIB_IPADDRTABLE));
if (pIPAddrTable)
{
// Make an initial call to GetIpAddrTable to get the
// necessary size into the dwSize variable
if (GetIpAddrTable(pIPAddrTable, &dwSize, 0) == ERROR_INSUFFICIENT_BUFFER)
{
printf("Not enough space, re-allocate...\n");
FREE(pIPAddrTable);
pIPAddrTable = (MIB_IPADDRTABLE *) MALLOC(dwSize);
if (pIPAddrTable == NULL)
{
printf("Memory re-allocation failed for GetIpAddrTable()\n");
exit(1);
}
else
printf("Memory re-allocation for GetIpAddrTable() is OK!\n");
}
else
printf("Buffer is sufficient...\n");
}
// Make a second call to GetIpAddrTable to get the actual data we want
if ( (dwRetVal = GetIpAddrTable( pIPAddrTable, &dwSize, 0 )) != NO_ERROR )
{
printf("GetIpAddrTable() failed with error %d\n", dwRetVal);
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);
}
exit(1);
}
else
printf("GetIpAddrTable() should be fine!\n");
printf("\n\tNumber of entries: %ld\n", pIPAddrTable->dwNumEntries);
for (i=0; i < (int) pIPAddrTable->dwNumEntries; i++)
{
printf("\n\tInterface Index[%d]:\t%ld\n", i, pIPAddrTable->table[i].dwIndex);
IPAddr.S_un.S_addr = (u_long) pIPAddrTable->table[i].dwAddr;
printf("\tIP Address[%d]: \t%s\n", i, inet_ntoa(IPAddr) );
IPAddr.S_un.S_addr = (u_long) pIPAddrTable->table[i].dwMask;
printf("\tSubnet Mask[%d]: \t%s\n", i, inet_ntoa(IPAddr) );
IPAddr.S_un.S_addr = (u_long) pIPAddrTable->table[i].dwBCastAddr;
printf("\tBroadCast[%d]: \t%s (%ld%)\n", i, inet_ntoa(IPAddr), pIPAddrTable->table[i].dwBCastAddr);
printf("\tReassembly size[%d]:\t%ld\n", i, pIPAddrTable->table[i].dwReasmSize);
printf("\tType and State[%d]:", i);
if (pIPAddrTable->table[i].wType & MIB_IPADDR_PRIMARY)
printf("\tPrimary IP Address");
if (pIPAddrTable->table[i].wType & MIB_IPADDR_DYNAMIC)
printf("\tDynamic IP Address");
if (pIPAddrTable->table[i].wType & MIB_IPADDR_DISCONNECTED)
printf("\tAddress is on disconnected interface");
if (pIPAddrTable->table[i].wType & MIB_IPADDR_DELETED)
printf("\tAddress is being deleted");
if (pIPAddrTable->table[i].wType & MIB_IPADDR_TRANSIENT)
printf("\tTransient address");
printf("\n");
}
// Clean up/reset
if (pIPAddrTable)
{
FREE(pIPAddrTable);
pIPAddrTable = NULL;
}
return 0;
}
Build and run the project.
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Program Example Using AddIPAddress() Function
The AddIPAddress() function adds the specified IPv4 address to the specified adapter. Create a new empty Win32 console mode application and add the project/solution name.
Add the following source code.
// Description:
// The following example retrieves the IP address table to determine
// the interface index for the first adapter, then adds the IP address
// specified on command line to the first adapter. The IP address that was added is then deleted.
//
// Link to ws2_32.lib
#include <winsock2.h>
#include <ws2tcpip.h>
// Link to Iphlpapi.lib
#include <iphlpapi.h>
#include <stdio.h>
// Note: could also use malloc() and free()
#define MALLOC(x) HeapAlloc(GetProcessHeap(), 0, (x))
#define FREE(x) HeapFree(GetProcessHeap(), 0, (x))
int main(int argc, char **argv)
{
// Variables used by GetIpAddrTable
PMIB_IPADDRTABLE pIPAddrTable;
DWORD dwSize = 0;
DWORD dwRetVal = 0;
IN_ADDR IPAddr;
DWORD ifIndex;
// IPv4 address and subnet mask we will be adding
UINT iaIPAddress;
UINT iaIPMask;
// Variables where handles to the added IP are returned
ULONG NTEContext = 0;
ULONG NTEInstance = 0;
// Variables used to return error message
LPVOID lpMsgBuf;
// Validate the parameters
if (argc != 3)
{
printf("Usage: %s <IPAddress> <SubnetMask>\n", argv[0]);
exit(1);
}
iaIPAddress = inet_addr(argv[1]);
if (iaIPAddress == INADDR_NONE)
{
printf("Usage: %s <IPAddress> <SubnetMask>\n", argv[0]);
exit(1);
}
iaIPMask = inet_addr(argv[2]);
if (iaIPMask == INADDR_NONE)
{
printf("Usage: %s <IPAddress> <SubnetMask>\n", argv[0]);
exit(1);
}
// Before calling AddIPAddress we use GetIpAddrTable to get
// an adapter to which we can add the IP.
pIPAddrTable = (MIB_IPADDRTABLE *) MALLOC(sizeof (MIB_IPADDRTABLE));
if (pIPAddrTable == NULL)
{
printf("Error allocating memory needed to call GetIpAddrTable()\n");
exit (1);
}
else
{
dwSize = 0;
// Make an initial call to GetIpAddrTable to get the
// necessary size into the dwSize variable
if (GetIpAddrTable(pIPAddrTable, &dwSize, 0) == ERROR_INSUFFICIENT_BUFFER)
{
printf("Not enough space, re-allocate...\n");
FREE(pIPAddrTable);
pIPAddrTable = (MIB_IPADDRTABLE *) MALLOC(dwSize);
}
if (pIPAddrTable == NULL)
{
printf("Memory allocation failed for GetIpAddrTable()\n");
exit(1);
}
}
// Make a second call to GetIpAddrTable to get the
// actual data we want
if ((dwRetVal = GetIpAddrTable(pIPAddrTable, &dwSize, 0)) == NO_ERROR)
{
printf("Second call to GetIpAddrTable() is fine!\n");
// Save the interface index to use for adding an IP address
ifIndex = pIPAddrTable->table[0].dwIndex;
printf("\n\tInterface Index:\t%ld\n", ifIndex);
IPAddr.S_un.S_addr = (u_long) pIPAddrTable->table[0].dwAddr;
printf("\tIP Address: \t%s (%lu%)\n", inet_ntoa(IPAddr), pIPAddrTable->table[0].dwAddr);
IPAddr.S_un.S_addr = (u_long) pIPAddrTable->table[0].dwMask;
printf("\tSubnet Mask: \t%s (%lu%)\n", inet_ntoa(IPAddr), pIPAddrTable->table[0].dwMask);
IPAddr.S_un.S_addr = (u_long) pIPAddrTable->table[0].dwBCastAddr;
printf("\tBroadCast Address:\t%s (%lu%)\n", inet_ntoa(IPAddr), pIPAddrTable->table[0].dwBCastAddr);
printf("\tReassembly size: \t%lu\n\n", pIPAddrTable->table[0].dwReasmSize);
}
else
{
printf("Call to GetIpAddrTable failed with error %d.\n", dwRetVal);
if (pIPAddrTable)
FREE(pIPAddrTable);
exit(1);
}
if (pIPAddrTable)
{
FREE(pIPAddrTable);
pIPAddrTable = NULL;
}
if ((dwRetVal = AddIPAddress(iaIPAddress, iaIPMask, ifIndex, &NTEContext, &NTEInstance)) == NO_ERROR)
{
printf("\tIPv4 address %s was successfully added.\n", argv[1]);
}
else
{
printf("AddIPAddress failed with error: %d\n", dwRetVal);
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);
exit(1);
}
}
// If you want to 'se' the added address, comment out the
// following part, add the IP address, then ping the address
// or use ipconfig /all
// Delete the IP we just added using the NTEContext
// variable where the handle was returned
if ((dwRetVal = DeleteIPAddress(NTEContext)) == NO_ERROR)
{
printf("\tIPv4 address %s was successfully deleted.\n", argv[1]);
}
else
{
printf("\tDeleteIPAddress failed with error: %d\n", dwRetVal);
exit(1);
}
return 0;
}
Build and run the project.
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