NAME

accf_data — buffer incoming connections until data arrives

SYNOPSIS

options INET

options ACCEPT_FILTER_DATA

kldload accf_data

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 data arrives on the connection.

The ACCEPT_FILTER_DATA 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_DATA has been included in the kernel config file or the accf_data module has been loaded, this will enable the data accept filter on the socket sok.

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

SEE ALSO

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

HISTORY

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

AUTHORS

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