Interactive User Interface

Article
06/30/2006

An interactive UI for the authentication protocol may also be implemented. The interactive UI allows the authentication protocol to obtain additional information from the user as needed during the course of the authentication session.

The interactive UI can be implemented in the same DLL as the authentication protocol, or in a separate DLL. Also, the DLL that implements the interactive UI can support more than one authentication protocol. The path to the DLL for the interactive UI is stored in the RAS_EAP_VALUENAME_INTERACTIVEUI registry value, under the key for the authentication protocol. For more information about creating this registry value, see EAP Installation.

The DLL for the interactive UI should export entry points for the following functions.

The interactive UI must support WM_COMMAND messages where LOWORD (wParam) equals IDCANCEL.

To display the interactive UI, the authentication protocol should set the fInvokeInteractiveUI member of the PPP_EAP_OUTPUT structure to TRUE. The authentication protocol may optionally set the pUIContextData and dwSizeOfUIContextData members as well. RAS uses the values of these members to pass context data to the interactive UI. The authentication protocol returns this PPP_EAP_OUTPUT structure as a parameter in the RasEapMakeMessage function.

RAS invokes the interactive UI by calling RasEapInvokeInteractiveUI. RAS passes the authentication protocol a pointer to the data returned by the interactive UI in the subsequent call to RasEapMakeMessage. The pointer is passed as a member of a PPP_EAP_INPUT structure. After RasEapMakeMessage returns, RAS calls RasEapFreeMemory to free the memory occupied by the information. Therefore, the authentication protocol should copy the information into a private memory buffer during the call to RasEapMakeMessage.

Interactive User Interface

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