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.Cd options INET 34.Cd options ACCEPT_FILTER_DATA 35.Pp 36In 37.Xr rc.conf 5 : 38.Cd kld_list="accf_data" 39.Sh DESCRIPTION 40This is a filter to be placed on a socket that will be using 41.Fn accept 42to receive incoming connections. 43.Pp 44It prevents the application from receiving the connected descriptor via 45.Fn accept 46until data arrives on the connection. 47.Pp 48The 49.Fa ACCEPT_FILTER_DATA 50kernel option is also a module that can be enabled at runtime via 51.Xr kldload 8 52if the INET option has been compiled into the kernel. 53.Sh EXAMPLES 54Assuming ACCEPT_FILTER_DATA has been included in the kernel config 55file or the 56.Nm 57module 58has been loaded, this will enable the data accept filter 59on the socket 60.Fa sok . 61.Bd -literal -offset 0i 62 struct accept_filter_arg afa; 63 64 bzero(&afa, sizeof(afa)); 65 strcpy(afa.af_name, "dataready"); 66 setsockopt(sok, SOL_SOCKET, SO_ACCEPTFILTER, &afa, sizeof(afa)); 67.Ed 68.Sh SEE ALSO 69.Xr setsockopt 2 , 70.Xr accept_filter 9 , 71.Xr accf_dns 9 , 72.Xr accf_http 9 73.Sh HISTORY 74The accept filter mechanism and the 75accf_data filter were introduced in 76.Fx 4.0 . 77.Sh AUTHORS 78This manual page and the filter were written by 79.An Alfred Perlstein . 80