ACCF_DATA(9)

okay so bestie, welcome to ACCF_DATA(9) — the Kernel Developer's Manual page that's literally about making incoming connections wait for actual data before they get handed over ✨

💖 NAME 💖

accf_data — buffer incoming connections until data arrives.

✨ SYNOPSIS ✨

options INET
options ACCEPT_FILTER_DATA

In rc.conf(5):

kld_list="accf_data"

🦋 DESCRIPTION 🦋

This is a filter you place on a socket that's gonna use accept() to receive incoming connections. iconic behavior 💅

It stops the application from receiving the connected descriptor via accept() until data arrives on the connection. no cap — it lowkey makes the app wait for the good stuff.

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. yep, that's the whole vibe 🫶

🌸 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. vintage but still slaying 🎀

🎀 AUTHORS 🎀

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

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and that's the whole page, bestie — source/version is Debian, dated November 15, 2000. mwah 💅💖