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ACCF_HTTP(9)		   Kernel Developer's Manual		  ACCF_HTTP(9)

NAME
       accf_http  -- buffer incoming connections until a certain complete HTTP
       requests	arrive

SYNOPSIS
       options INET
       options ACCEPT_FILTER_HTTP
       kldload accf_http

DESCRIPTION
       This is a filter	to be placed on	a socket that will be  using  accept()
       to receive incoming HTTP	connections.

       It prevents the application from	receiving the connected	descriptor via
       accept()	 until	either a full HTTP/1.0 or HTTP/1.1 HEAD	or GET request
       has been	buffered by the	kernel.

       If something other than a HTTP/1.0 or HTTP/1.1 HEAD or GET  request  is
       received	 the  kernel will allow	the application	to receive the connec-
       tion descriptor via accept().

       The utility of accf_http	is such	that a server will not have to context
       switch several times before performing the initial parsing of  the  re-
       quest.  This effectively	reduces	the amount of required CPU utilization
       to  handle  incoming requests by	keeping	active processes in preforking
       servers such as Apache low and reducing the size	of the file descriptor
       set that	needs to be managed by interfaces such as select(), poll()  or
       kevent()	based servers.

       The  accf_http  kernel  option  is also a module	that can be enabled at
       runtime via kldload(8) if the INET option has been  compiled  into  the
       kernel.

EXAMPLES
       Assuming	ACCEPT_FILTER_HTTP has been included in	the kernel config file
       or  the accf_http module	has been loaded, this will enable the http ac-
       cept filter on the socket sok.

	       struct accept_filter_arg	afa;

	       bzero(&afa, sizeof(afa));
	       strcpy(afa.af_name, "httpready");
	       setsockopt(sok, SOL_SOCKET, SO_ACCEPTFILTER, &afa, sizeof(afa));

SEE ALSO
       setsockopt(2), accept_filter(9)

HISTORY
       The accept filter mechanism and the accf_http filter were introduced in
       FreeBSD 4.0.

AUTHORS
       This manual page	and the	filter were written by Alfred Perlstein.

FreeBSD	13.2		       November	15, 2000		  ACCF_HTTP(9)

NAME | SYNOPSIS | DESCRIPTION | EXAMPLES | SEE ALSO | HISTORY | AUTHORS

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