accf_data — buffer incoming connections until data arrives

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

Debian                                          November 15, 2000                                   ACCF_DATA(9)

       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.

       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));

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

       accf_data — buffer incoming connections until data arrives

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

optionsINEToptionsACCEPT_FILTER_DATAkldloadaccf_data