/*
* main
*
* this is where it all happens
*/
int main(int argc, char * argv[])
{
DWORD dwResult; // result from API call
DWORD dwVersion; // API version reported
WCHAR wszAdapter[MAX_ADAPTER_NAME] = {0}; // the adapter name in wide chars
char * ptr = NULL; // pointer to adapter name
if (argc > 1)
ptr = argv[1];
else
ptr = DetermineAdapter();
// convert it for the API call
MultiByteToWideChar(0, 0, ptr, (int) strlen(ptr), wszAdapter, MAX_ADAPTER_NAME);
// initialize the DHCP Client Options API
dwResult = DhcpCApiInitialize(&dwVersion);
if (dwResult != 0)
{
OutputError(dwResult);
exit(4);
}
else
printf("DHCP Client Options API version %d\n", dwVersion);
//
// Here the request is set up - since this is an easy example, the request
// is set up statically, however in a real-world scenario this may require
// building the request array in a more 'dynamic' way
//
// Also for this sample we are using two items that are almost always in a
// DHCP configuration. Hence this information is retrieved from the local
// DHCP cache.
//
// the DHCP Client Options API arrays for getting the options
DHCPCAPI_PARAMS requests[2] =
{{0, OPTION_SUBNET_MASK, FALSE, NULL, 0}, // subnet mask
{0, OPTION_ROUTER_ADDRESS, FALSE, NULL, 0}}; // gateway address
// set-up the actual arrays
DHCPCAPI_PARAMS_ARRAY sendarray = {0, NULL}; // we aren't sending anything
DHCPCAPI_PARAMS_ARRAY requestarray = {2, requests}; // we are requesting 2
// buffer variables
DWORD dwSize = INITIAL_BUFFER_SIZE; // size of buffer for options
LPBYTE buffer = NULL; // buffer for options
IN_ADDR addr; // address in return code
printf("Getting DHCP Options on Adapter [%S]\n", wszAdapter);
// loop until buffer is big enough to get the data and then make request
do
{
if (buffer)
LocalFree(buffer);
buffer = (LPBYTE) LocalAlloc(LPTR, dwSize); // allocate the buffer
if (!buffer)
{
OutputError(GetLastError());
exit(5);
}
// make the request on the adapter
dwResult = DhcpRequestParams(DHCPCAPI_REQUEST_SYNCHRONOUS,
NULL,
wszAdapter,
NULL, sendarray,
requestarray,
buffer, &dwSize,
NULL);
}
while (dwResult == ERROR_MORE_DATA);
// parse out results
if (dwResult == ERROR_SUCCESS)
{
// first check subnet
if (requests[0].nBytesData > 0)
{
memcpy(&addr, (LPVOID) requests[0].Data, 4);
printf("Subnet Mask: %s\n", inet_ntoa(addr));
}
else
printf("Subnet Mask NOT present!\n");
// check for router address
if (requests[1].nBytesData > 0)
{
memcpy(&addr, (LPVOID) requests[1].Data, 4);
printf("Gateway Address: %s\n", inet_ntoa(addr));
}
else
printf("Gateway Address NOT present!\n");
}
else
{
OutputError(dwResult);
}
// free the buffer
if (buffer)
LocalFree(buffer);
// de-init the api
DhcpCApiCleanup();
return 0;
}
/*
* main
*
* this is where it all happens
*/
int main(int argc, char * argv[])
{
DWORD dwResult; // result from API call
DWORD dwVersion; // API version reported
WCHAR wszAdapter[MAX_ADAPTER_NAME] = {0}; // the adapter name in wide chars
char * ptr = NULL; // pointer to adapter name
BOOL bRemovePersist = FALSE; // remove persistent request
BOOL bAddPersist = FALSE; // add persistent request
// check for persist options and adapter ID
for (int i = 1; i < argc; i++)
{
char * p;
p = argv[i];
if ((p[0] == '/') || (p[0] == '-'))
{
p++;
if ((p[0] == 'p') || (p[0] == 'P'))
bAddPersist = TRUE;
if ((p[0] == 'r') || (p[0] == 'R'))
bRemovePersist = TRUE;
}
else
ptr = argv[i];
}
if (!ptr)
ptr = DetermineAdapter();
// convert it for the API call
MultiByteToWideChar(0, 0, ptr, (int) strlen(ptr), wszAdapter, MAX_ADAPTER_NAME);
// initialize the DHCP Client Options API
dwResult = DhcpCApiInitialize(&dwVersion);
if (dwResult != 0)
{
OutputError(dwResult);
exit(4);
}
else
printf("DHCP Client Options API version %d\n", dwVersion);
printf("Setting DHCP Options on Adapter [%S]\n", wszAdapter);
// remove persistence if required
if (bRemovePersist)
{
printf("Removing Option Persistence...\n");
dwResult = DhcpUndoRequestParams(0, NULL, wszAdapter,
DHCP_PERSISTENT_APP_STRING);
if (dwResult != ERROR_SUCCESS)
OutputError(dwResult);
}
else
{
//
// Here the request is set up - since this is an easy example, the request
// is set up statically, however in a real-world scenario this may require
// building the request array in a more 'dynamic' way
//
// the DHCP Client Options API arrays for getting the options
DHCPCAPI_PARAMS requests[1] =
{{0, OPTION_TIME_SERVERS, FALSE, NULL, 0}}; // gateway address
// set-up the actual arrays
DHCPCAPI_PARAMS_ARRAY sendarray = {0, NULL}; // we aren't sending anything
DHCPCAPI_PARAMS_ARRAY requestarray = {1, requests}; // we are requesting 1
// buffer variables
DWORD dwSize = INITIAL_BUFFER_SIZE; // size of buffer for options
LPBYTE buffer = NULL; // buffer for options
IN_ADDR addr; // address in return code
// loop until buffer is big enough to get the data and then make request
do
{
if (buffer)
LocalFree(buffer);
buffer = (LPBYTE) LocalAlloc(LPTR, dwSize); // allocate the buffer
if (!buffer)
{
OutputError(GetLastError());
exit(5);
}
// make the request on the adapter
DWORD dwFlags = DHCPCAPI_REQUEST_SYNCHRONOUS;
if (bAddPersist)
{
dwFlags = DHCPCAPI_REQUEST_PERSISTENT;
printf("Making the request persistent...\n");
}
dwResult = DhcpRequestParams(dwFlags,
NULL,
wszAdapter,
NULL, sendarray,
requestarray,
buffer, &dwSize,
bAddPersist ?
DHCP_PERSISTENT_APP_STRING : NULL);
}
while (dwResult == ERROR_MORE_DATA);
// parse out results only if we made the synchronous request
if (dwResult == ERROR_SUCCESS)
{
if (bAddPersist != TRUE)
{
// check for time server
if (requests[0].nBytesData > 0)
{
memcpy(&addr, (LPVOID) requests[0].Data, 4);
printf("Time Server: %s\n", inet_ntoa(addr));
}
else
printf("Time Server NOT present!\n");
}
}
else
{
OutputError(dwResult);
}
// free the buffer
if (buffer)
LocalFree(buffer);
}
// de-init the api
DhcpCApiCleanup();
return 0;
}