Once built and installed: (make install), you can load these with
soconfig -F httpf httpf prog 2:2:0,2:2:6,26:2:0,26:2:6
soconfig -F dataf dataf prog 2:2:0,2:2:6,26:2:0,26:2:6
Then applications must programatically enable them immediately after socket() and before bind() with a setsockopt() call as follows:
setsockopt(fd, SOL_FILTER, FIL_ATTACH, "httpf", 6);
or
setsockopt(fd, SOL_FILTER, FIL_ATTACH, "dataf", 6);
This is a kernel module that use the sockfs filtering API. In the httpf filter case, the accept notification is deferred for new passive sockets until:
- 4 bytes are read that are not GET, HEAD, POST, PUT (trailing spaces where needed).
- a \r\n\r\n or \n\n are found after the initial 4 bytes.
- 8192 bytes are read
In the dataf filter case, the accept is defered until at least one byte of data is received on the TCP session from the remote client.