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ACCF_DNS(9)	       FreeBSD 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_http(9) accf_data(9)

HISTORY
     The accept	filter mechanism was introduced	in FreeBSD 4.0.

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

FreeBSD	10.1			 July 16, 2008			  FreeBSD 10.1

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

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