DTLS_GET_DATA_MTU(3ossl)

📦 version 3.5.0, in opensuse-leap 16.0

💅 DTLS_GET_DATA_MTU(3ossl) — the girlies' guide to DTLS_get_data_mtu

okay so bestie, welcome to DTLS_GET_DATA_MTU(3ossl), a manual page in the OpenSSL 3ossl girlie universe. It's short, it's sweet, and it's literally about one function. Let's get into it ✨

🌸 NAME

DTLS_get_data_mtu — get the maximum data payload size 🎀

🦋 SYNOPSIS

#include <openssl/ssl.h>

size_t DTLS_get_data_mtu(const SSL *ssl);

like, that's the whole vibe. one include, one function, zero drama 💅

💖 DESCRIPTION

so this function gives you the maximum data payload size for the established DTLS connection ssl 👑

and how does it figure that out? it's math, bestie. it takes the DTLS record MTU and subtracts the overhead of:

  • the DTLS record header
  • encryption
  • authentication

...all of which are currently in use on that connection. so it's not some generic guess — it's tailored to what ssl is actually doing rn. iconic behavior honestly 🫶

✨ RETURN VALUES

  • on success — it returns the maximum data payload size 🌈
  • on failure — it returns 0 💀

so yeah, if you get 0, that's your sign something did not slay. check it, don't just assume zero bytes is a valid answer 🙈

🕰️ HISTORY

DTLS_get_data_mtu() was added in OpenSSL 1.1.1 ⭐ so if you're on something older, this function is not going to pick up the phone, no cap.

Copyright 2016 The OpenSSL Project Authors. All Rights Reserved. 🎀

Licensed under the Apache License 2.0 (the "License"). You may not use this file except in compliance with the License. You can obtain a copy in the file LICENSE in the source distribution or at <https://www.openssl.org/source/license.html>.

fr fr read the license, it's giving legally binding but make it fashion 💜

and that's the page, bestie 🧚 this little transmission was brought to you by version 3.5.0, dated 2026-09-25, filed under DTLS_GET_DATA_MTU(3ossl) — stay encrypted, stay iconic 💖🌸

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