accf_http(9) [freebsd man page]

ACCF_HTTP(9)						   BSD 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
     request.  This effectively reduces the amount of required CPU utilization to handle incoming requests by keeping active processes in prefork-
     ing 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 ker-
     nel.

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
     accept 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.

BSD
								 November 15, 2000							       BSD

Check Out this Related Man Page

ACCF_DNS(9)						   BSD Kernel Developer's Manual					       ACCF_DNS(9)

NAME

     accf_dns -- buffer incoming DNS requests until the whole first request is present

SYNOPSIS

     options INET
     options ACCEPT_FILTER_DNS
     kldload accf_dns

DESCRIPTION

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

     It prevents the application from receiving the connected descriptor via accept() until a whole DNS request is available on the socket.  It
     does this by reading the first two bytes of the request, to determine its size, and waiting until the required amount of data is available to
     be read.

     The ACCEPT_FILTER_DNS 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

     If the accf_dns module is available in the kernel, the following code will enable the DNS accept filter on a socket sok.

	     struct accept_filter_arg afa;

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

SEE ALSO

     setsockopt(2), accept_filter(9), accf_data(9), accf_http(9)

HISTORY

     The accept filter mechanism was introduced in FreeBSD 4.0.

AUTHORS

     This manual page and the filter were written by David Malone.

BSD
								   July 16, 2008							       BSD

Linux and UNIX Man Pages

accf_http(9) [freebsd man page]

Check Out this Related Man Page