SSL_SET_SHUTDOWN(3ossl)

📦
version 15.1 · 3 versions
, in freebsd 15.1

💅 SSL_SET_SHUTDOWN — the OpenSSL manual page, but make it make sense (3ossl)

okay so bestie, you found the SSL_SET_SHUTDOWN(3ossl) page in the OpenSSL manual and ngl it's kinda dry 💀 let me give you the group-chat translation, no cap.

✨ NAME ✨

SSL_set_shutdown, SSL_get_shutdown — literally the two functions that let you read and mess with the shutdown state of an SSL connection 🎀

🌸 SYNOPSIS 🌸

#include <openssl/ssl.h>

void SSL_set_shutdown(SSL *ssl, int mode);

int SSL_get_shutdown(const SSL *ssl);

that's it, that's the whole vibe ✨

🦋 DESCRIPTION 🦋

So SSL_set_shutdown() sets the shutdown state of ssl to mode. Simple. Iconic. 🫶

And SSL_get_shutdown() returns the shutdown mode of ssl — it's giving "read-only bestie" energy.

👑 NOTES 👑

The shutdown state of an ssl connection is a bit-mask of these, periodt:

  • 0 — no shutdown setting yet, we're just vibing 🙈
  • SSL_SENT_SHUTDOWN — a close_notify shutdown alert was sent to the peer, the connection is being considered closed, and the session is closed and correct. ✅ slay.
  • SSL_RECEIVED_SHUTDOWN — a shutdown alert was received from the peer, either a normal close_notify or a fatal error. 😭

okay and heads up: SSL_SENT_SHUTDOWN and SSL_RECEIVED_SHUTDOWN can both be set at the same time — they're not mutually exclusive, it's not a competition 💅

The shutdown state of the connection is used to determine the state of the ssl session. If the session is still open when SSL_clear(3) or SSL_free(3) is called, it's considered bad and removed according to RFC2246. 🚩

The actual condition for a correctly closed session is SSL_SENT_SHUTDOWN — according to the TLS RFC, it's acceptable to only send the close_notify alert but to not wait for the peer's answer when the underlying connection is closed. So basically you can say bye and dip. 🏃‍♀️💨

SSL_set_shutdown() can be used to set this state without sending a close alert to the peer (see SSL_shutdown(3)). lowkey powerful.

If a close_notify was received, SSL_RECEIVED_SHUTDOWN will be set. But for setting SSL_SENT_SHUTDOWN, the application must however still call SSL_shutdown(3) or SSL_set_shutdown() itself. It doesn't, like, do it for you. 🙃

🚩 real talk: SSL_set_shutdown() is not supported for QUIC SSL objects. not supported, not a vibe, don't try it.

⭐ RETURN VALUES ⭐

  • SSL_set_shutdown() does not return diagnostic information. it's giving "no thoughts, head empty" — it just does the thing and says nothing. 💀
  • SSL_get_shutdown() returns the current shutdown state, as set or based on the actual connection state.

And here's the QUIC tea 🍵 — SSL_get_shutdown() returns 0 if called on a QUIC stream SSL object. If it's called on a QUIC connection SSL object, it returns a value with SSL_SENT_SHUTDOWN set if CONNECTION_CLOSE has been sent to the peer, and it returns a value with SSL_RECEIVED_SHUTDOWN set if CONNECTION_CLOSE has been received from the peer or the QUIC connection is fully terminated for other reasons. iykyk 🧚

🌈 SEE ALSO 🌈

go read those too, they're the supporting cast and they ate 🔥

Copyright 2001-2023 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>.

and that's the whole page bestie 🫶 this version of the page is from 3.5.6, dated 2026-04-07 — go forth and shut down your connections correctly, mwah 💋🎀

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