1.\" 2.\" Copyright (c) 2000 Alfred Perlstein 3.\" 4.\" All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY EXPRESS OR 16.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18.\" IN NO EVENT SHALL THE DEVELOPERS BE LIABLE FOR ANY DIRECT, INDIRECT, 19.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25.\" " 26.Dd November 15, 2000 27.Dt ACCF_DATA 9 28.Os 29.Sh NAME 30.Nm accf_data 31.Nd buffer incoming connections until data arrives 32.Sh SYNOPSIS 33.Nm options INET 34.Nm options ACCEPT_FILTER_DATA 35.Nm kldload accf_data 36.Sh DESCRIPTION 37This is a filter to be placed on a socket that will be using 38.Fn accept 39to receive incoming connections. 40.Pp 41It prevents the application from receiving the connected descriptor via 42.Fn accept 43until data arrives on the connection. 44.Pp 45The 46.Fa ACCEPT_FILTER_DATA 47kernel option is also a module that can be enabled at runtime via 48.Xr kldload 8 49if the INET option has been compiled into the kernel. 50.Sh EXAMPLES 51Assuming ACCEPT_FILTER_DATA has been included in the kernel config 52file or the 53.Nm 54module 55has been loaded, this will enable the data accept filter 56on the socket 57.Fa sok . 58.Bd -literal -offset 0i 59 struct accept_filter_arg afa; 60 61 bzero(&afa, sizeof(afa)); 62 strcpy(afa.af_name, "dataready"); 63 setsockopt(sok, SOL_SOCKET, SO_ACCEPTFILTER, &afa, sizeof(afa)); 64.Ed 65.Sh SEE ALSO 66.Xr setsockopt 2 , 67.Xr accept_filter 9 , 68.Xr accf_dns 9 , 69.Xr accf_http 9 70.Sh HISTORY 71The accept filter mechanism and the 72accf_data filter were introduced in 73.Fx 4.0 . 74.Sh AUTHORS 75This manual page and the filter were written by 76.An Alfred Perlstein . 77