This module requires the service of mod_proxy. It provides support for the passing the socket of the client to another process.

mod_proxy_fdpass uses the ability of AF_UNIX domain sockets to pass an open file descriptor to allow another process to finish handling a request.

The module has a proxy_fdpass_flusher provider interface, which allows another module to optionally send the response headers, or even the start of the response body. The default flush provider disables keep-alive, and sends the response headers, letting the external process just send a response body.

In order to use another provider, you have to set the flusher parameter in the ProxyPass directive.

At this time the only data passed to the external process is the client socket. To receive a client socket, call recvfrom with an allocated struct cmsghdr. Future versions of this module may include more data after the client socket, but this is not implemented at this time.