How to set l2tp preshared key? - c

Question

I need to create RASENTRY for L2TP with pre-shared key set. So far, I can see that entry has somewhat correct flags, but no key is set, unfortunately.
Here is code:
int common_ras_manager_create_entry(const char* server_address, const char* username, const char* password, MY_VPN_CONNECTION_TYPE connection_type, const char* preshared_key)
{
DWORD EntryInfoSize = 0;
DWORD DeviceInfoSize = 0;
DWORD Ret;
LPRASENTRY lpRasEntry;
LPBYTE lpDeviceInfo;
// Get buffer sizing information for a default phonebook entry
if ((Ret = RasGetEntryProperties(NULL, "", NULL, &EntryInfoSize, lpDeviceInfo, &DeviceInfoSize)) != 0)
{
if (Ret != ERROR_BUFFER_TOO_SMALL)
{
printf("RasGetEntryProperties sizing failed with error %d\n", Ret);
return Ret;
}
}
lpRasEntry = (LPRASENTRY) GlobalAlloc(GPTR, EntryInfoSize);
if (DeviceInfoSize == 0)
lpDeviceInfo = NULL;
else
lpDeviceInfo = (LPBYTE) GlobalAlloc(GPTR, DeviceInfoSize);
// Get default phonebook entry
lpRasEntry->dwSize = sizeof(RASENTRY);
if ((Ret = RasGetEntryProperties(NULL, "", lpRasEntry, &EntryInfoSize, lpDeviceInfo, &DeviceInfoSize)) != 0)
{
printf("RasGetEntryProperties failed with error %d\n", Ret);
return Ret;
}
// Validate new phonebook name "Testentry"
if ((Ret = RasValidateEntryName(NULL, APP_NAME)) != ERROR_SUCCESS)
{
printf("RasValidateEntryName failed with error %d\n", Ret);
if (Ret != ERROR_ALREADY_EXISTS)
return Ret;
}
LPRASDEVINFO ras_devices;
DWORD cb =sizeof(RASDEVINFO);
DWORD cbDevices = 0;
ras_devices = (LPRASDEVINFO)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, cb);
if (NULL == ras_devices)
{
printf("HeapAlloc failed.\n");
return ERROR_OUTOFMEMORY;
}
ras_devices->dwSize = sizeof(RASDEVINFO);
if ((Ret = RasEnumDevices(ras_devices, &cb, &cbDevices)) != ERROR_SUCCESS)
{
printf("RasEnumDevices failed with error %d\n", Ret);
switch(Ret)
{
case ERROR_BUFFER_TOO_SMALL:
printf("buffer too small");
HeapFree(GetProcessHeap(), 0, (LPVOID)ras_devices);
ras_devices = (LPRASDEVINFO)HeapAlloc(GetProcessHeap(), HEAP_ZERO_MEMORY, cb);
if (NULL == ras_devices)
{
printf("HeapAlloc failed.\n");
return ERROR_OUTOFMEMORY;
}
ras_devices->dwSize = sizeof(RASDEVINFO);
Ret = RasEnumDevices(ras_devices, &cb, &cbDevices);
if (ERROR_SUCCESS == Ret)
{
//fSuccess = TRUE;
}
else
{
printf("RasEnumDevices failed again: Error = %d\n", Ret);
return Ret;
//goto done;
}
break;
case ERROR_NOT_ENOUGH_MEMORY:
printf("ERROR_NOT_ENOUGH_MEMORY");
return Ret;
break;
case ERROR_INVALID_PARAMETER:
printf("ERROR_INVALID_PARAMETER");
return Ret;
break;
case ERROR_INVALID_USER_BUFFER:
printf("ERROR_INVALID_USER_BUFFER");
return Ret;
break;
}
}
DWORD dwVpnStrategy = 0;
char device_name_mask[5];
strcpy(device_name_mask, "");
gboolean preshared_key_valid = 0;
switch(connection_type)
{
case PPTP:
strcpy(device_name_mask, "PPTP");
dwVpnStrategy = VS_PptpOnly;
break;
case L2TP:
if (preshared_key == 0 || strlen(preshared_key) == 0)
{
printf("CRITICAL: preshared key not set.");
return 1;
}
else
{
preshared_key_valid = TRUE;
}
strcpy(device_name_mask, "L2TP");
dwVpnStrategy = VS_L2tpOnly;
break;
}
int i =0;
for (i = 0; i < cbDevices; i++)
{
RASDEVINFO r = ras_devices[i];
if (strstr(r.szDeviceName, device_name_mask))
{
break;
}
}
//lpRasEntry->dwfOptions |= RASEO_SpecificIpAddr;
//lpRasEntry->szLocalPhoneNumber = RASDT_Vpn;
lpRasEntry->dwfNetProtocols |= RASNP_Ip;
lpRasEntry->dwFramingProtocol = RASFP_Ppp;
lstrcpy(lpRasEntry->szDeviceType, RASDT_Vpn);
lstrcpy(lpRasEntry->szDeviceName, ras_devices[i].szDeviceName);
lstrcpy(lpRasEntry->szLocalPhoneNumber, server_address);
lpRasEntry->dwVpnStrategy = dwVpnStrategy; // VS_PptpOnly; VS_SstpOnly
if (preshared_key_valid)
{
L2TP_CONFIG_DATA* data = GlobalAlloc(GPTR, sizeof(L2TP_CONFIG_DATA));
lpRasEntry->dwfOptions2 |= RASEO2_UsePreSharedKey;
data->dwOffsetKey = 16;
memcpy((PBYTE)data + data->dwOffsetKey, preshared_key, strlen(preshared_key));
data->dwAuthType =L2TP_IPSEC_AUTH_PRESHAREDKEY;
RasSetCustomAuthData(NULL, APP_NAME, data, sizeof(L2TP_CONFIG_DATA));
}
if ((Ret = RasSetEntryProperties(NULL, APP_NAME, lpRasEntry, EntryInfoSize, lpDeviceInfo, DeviceInfoSize)) != 0)
{
printf("RasSetEntryProperties failed with error %d\n", Ret);
return Ret;
}
//if ((Ret = RasSetCredentials(NULL, lpRasEntry.))
}
I cant find where is buffer to fill for pre-shared key.

Answer 1

Following code works fine.
// l2tp
if (preshared_key_valid)
{
RASCREDENTIALS ras_cre_psk = {0};
ras_cre_psk.dwSize = sizeof(ras_cre_psk);
ras_cre_psk.dwMask = 0x00000010; //RASCM_PreSharedKey;
wcscpy(ras_cre_psk.szPassword, preshared_key);
if ((Ret = RasSetCredentials(NULL, APP_NAME, &ras_cre_psk, FALSE)))
{
printf("RasSetCredentials failed with error %d\n", Ret);
return Ret;
}
}