SSL_SET_SHUTDOWN(3ossl)

📦
version 3.5.9 · 8 versions
, in fedora 43, fedora 44

💅 SSL_SET_SHUTDOWN — bestie, it's time to say goodbye (but politely) 💅

okay so this is the 3ossl manual page, and it's all about manipulating the shutdown state of an SSL connection. yes, we're doing closure. very healing of us. ✨

🌸 NAME 🌸

SSL_set_shutdown, SSL_get_shutdown — manipulate 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);

💖 DESCRIPTION 💖

SSL_set_shutdown() sets the shutdown state of ssl to mode. that's it, that's the whole vibe. you're literally telling the connection how shut down it is.

SSL_get_shutdown() returns the shutdown mode of ssl. reading the room, basically. 👑

✨ NOTES ✨

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

  • 0 — No shutdown setting, yet. (it's giving "we haven't talked about it" 😭)
  • 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. ✅ iconic, correct, well-behaved.
  • SSL_RECEIVED_SHUTDOWN — A shutdown alert was received from the peer, either a normal close_notify or a fatal error. 💀 okay so sometimes it's a nice goodbye and sometimes it's a crash-out.

SSL_SENT_SHUTDOWN and SSL_RECEIVED_SHUTDOWN can be set at the same time. both things can be true, we contain multitudes. 🦋

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 is considered bad and removed according to RFC2246. 😬 not the "left them on read" energy we're going for.

The actual condition for a correctly closed session is SSL_SENT_SHUTDOWN — according to the TLS RFC, it is acceptable to only send the close_notify alert but to not wait for the peer's answer, when the underlying connection is closed. so like, you can send the text and then immediately close the app. valid.

SSL_set_shutdown() can be used to set this state without sending a close alert to the peer (see SSL_shutdown(3)). sneaky. ghosting, but with API support. 🙈

If a close_notify was received, SSL_RECEIVED_SHUTDOWN will be set. For setting SSL_SENT_SHUTDOWN the application must however still call SSL_shutdown(3) or SSL_set_shutdown() itself. nobody's doing it for you, bestie, you have to do it yourself. 💅

⚠️ heads up: SSL_set_shutdown() is not supported for QUIC SSL objects. different girl, different rules. 🚫

🌈 RETURN VALUES 🌈

  • SSL_set_shutdown() does not return diagnostic information. it's mysterious like that. no feedback, no notes. 💀
  • SSL_get_shutdown() returns the current shutdown state as set, or based on the actual connection state.
  • SSL_get_shutdown() returns 0 if called on a QUIC stream SSL object.
  • If it is 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. so many reasons to be done, honestly. ✨

🫶 SEE ALSO 🫶

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 was OpenSSL 3.5.9, dated 2026-09-29, and it's SSL_SET_SHUTDOWN(3ossl) — now go forth and close your connections correctly. slay, goodbye, close_notify 💖✨🦋

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