![tcp redirector tcp redirector](https://www.net-usb.com/images/upload/UNG/articles/redirect/4.jpg)
Cast the writableLayerData out parameter to the structure corresponding to the layer, either FWPS_BIND_REQUEST0 or FWPS_CONNECT_REQUEST0. This must be done to prevent infinite redirecting.Ĭall FwpsAcquireClassifyHandle0 to obtain a handle that will be used for subsequent function calls.Ĭall FwpsAcquireWritableLayerDataPointer0 to get the writable data structure for the layer in which classifyFn was called. In Windows 8 and later, you must query the redirection state of the connection by using the FwpsQuer圜onnectionRedirectState0 function in your callout driver. (This step is omitted for Windows 7 and earlier.) This handle should be cached and used for all redirections.
TCP REDIRECTOR DRIVER
To perform redirection inline a callout driver must perform the following steps in its implementation of classifyFn:Ĭall FwpsRedirectHandleCreate0 to obtain a handle that can be used to redirect TCP connections. To use classifyFn1 or later, the callout must be registered by calling FwpsCalloutRegister1 or later, not the older FwpsCalloutRegister0.
![tcp redirector tcp redirector](https://i.imgur.com/KfTkD1q.png)
TCP REDIRECTOR DRIVERS
Callout drivers have the option of making changes either inline in their classifyFn functions, or asynchronously in another function.Ĭallout drivers that implement redirection must use classifyFn1 or later instead of classifyFn0 as their classification callout function.
![tcp redirector tcp redirector](https://www.flexihub.com/images/upload/flexihub/articles/rem-usb/USB_Redirector.gif)
A set of new functions are provided to obtain writable layer data and to apply it through the engine. To redirect a connection, the callout driver must obtain a writable copy of the TCP 4-tuple information, make changes to it as needed, and apply the changes. Raw UDPv4 without the header include option.The types of packets that are supported for redirection are shown in the following list: Redirection is not available for use with all types of network traffic. Callout drivers that support classification at these layers must register using FwpsCalloutRegister1 or higher, not the older FwpsCalloutRegister0 function. The redirect layers are only available for Windows 7 and later versions of Windows. Changes at bind layers affect all connections that are using that socket. Changes at connect layers affect only the flow being connected. The layer at which redirection is performed determines the effect of the change. Redirection can be performed by callout drivers at the following layers, which are called "redirect layers":įWPM_LAYER_ALE_BIND_REDIRECT_V4 (FWPS_LAYER_ALE_BIND_REDIRECT_V4)įWPM_LAYER_ALE_BIND_REDIRECT_V6 (FWPS_LAYER_ALE_BIND_REDIRECT_V6)įWPM_LAYER_ALE_CONNECT_REDIRECT_V4 (FWPS_LAYER_ALE_CONNECT_REDIRECT_V4)įWPM_LAYER_ALE_CONNECT_REDIRECT_V6 (FWPS_LAYER_ALE_CONNECT_REDIRECT_V6) This is not supported in the connect-redirect layer. The proxy service has two sockets: one for the redirected original connection and one for the new proxied outbound connection.Ī WFP redirect record is a buffer of opaque data that WFP must set on an outbound proxy connection at the FWPM_LAYER_ALE_AUTH_CONNECT_REDIRECT_V4 and FWPM_LAYER_ALE_AUTH_CONNECT_REDIRECT_V6 layers, so that the redirected connection and the original connection are logically related.Ĭhanging the local address and port of a flow is only supported in the bind-redirect layer.
TCP REDIRECTOR CODE
Note The ClassifyFunctions_Prox圜allouts.cpp module in the WFP driver sample includes code that demonstrates connect/bind redirection.Ī WFP connection redirection callout redirects an application's connection request so that the application connects to a proxy service instead of the original destination. This feature is available in Windows 7 and later.
TCP REDIRECTOR WINDOWS
The connect/bind redirection feature of the Windows Filtering Platform (WFP) enables application layer enforcement (ALE) callout drivers to inspect and, if desired, redirect connections.