SSL_CTX_set_domain_flags3ssl

Usage

 #include <openssl/ssl.h>
 #define SSL_DOMAIN_FLAG_SINGLE_THREAD
 #define SSL_DOMAIN_FLAG_MULTI_THREAD
 #define SSL_DOMAIN_FLAG_LEGACY_BLOCKING
 #define SSL_DOMAIN_FLAG_BLOCKING
 #define SSL_DOMAIN_FLAG_THREAD_ASSISTED
 int SSL_CTX_set_domain_flags(SSL_CTX *ctx, uint64_t flags);
 int SSL_CTX_get_domain_flags(SSL_CTX *ctx, uint64_t *flags);
 int SSL_get_domain_flags(SSL *ssl, uint64_t *flags);

Overview

SSL_CTX_set_domain_flags() and SSL_CTX_get_domain_flags() set and get the QUIC domain flags on a SSL_CTX using a QUIC SSL_METHOD. These flags determine the concurrency model which is used for a QUIC domain. A detailed introduction to these concepts can be found in openssl-quic-concurrency(7).

Applications may use either one the flags here:

SSL_DOMAIN_FLAG_SINGLE_THREAD

Specifying this flag configures the Single-Threaded Concurrency Model (SCM).

SSL_DOMAIN_FLAG_MULTI_THREAD

Specifying this flag configures the Contentive Concurrency Model (CCM) (unless SSL_DOMAIN_FLAG_THREAD_ASSISTED is also specified).

If OpenSSL was built without thread support, this is identical to SSL_DOMAIN_FLAG_SINGLE_THREAD.

SSL_DOMAIN_FLAG_THREAD_ASSISTED

Specifying this flag configures the Thread-Assisted Concurrency Model (TACM). It implies SSL_DOMAIN_FLAG_MULTI_THREAD and SSL_DOMAIN_FLAG_BLOCKING.

This concurrency model is not available if OpenSSL was built without thread support, in which case attempting to configure it will result in an error.

SSL_DOMAIN_FLAG_BLOCKING

Enable reliable support for blocking I/O calls, allocating whatever OS resources are necessary to realise this. If this flag is specified, SSL_DOMAIN_FLAG_LEGACY_BLOCKING is ignored.

SSL_DOMAIN_FLAG_LEGACY_BLOCKING

Enables legacy blocking compatibility mode. See "Legacy Blocking Support Compatibility" in openssl-quic-concurrency(7).

Mutually exclusive flag combinations result in an error (for example, combining SSL_DOMAIN_FLAG_SINGLE_THREAD and SSL_DOMAIN_FLAG_MULTI_THREADED).

Because exactly one concurrency model must be chosen, the domain flags cannot be set to 0 and attempting to do so will result in an error.

Changing these flags using SSL_CTX_set_domain_flags() has no effect on QUIC domains which have already been created.

The default set of domain flags set on a newly created SSL_CTX may vary by OpenSSL version, chosen SSL_METHOD, and operating environment. See openssl-quic-concurrency(7) for details. An application can retrieve the default domain flags by calling SSL_CTX_get_domain_flags() immediately after constructing a SSL_CTX.

SSL_get_domain_flags() retrieves the domain flags which are effective for a QUIC domain when called on any QUIC SSL object under that domain.

Return values

SSL_CTX_set_domain_flags(), SSL_CTX_get_domain_flags() and SSL_get_domain_flags() return 1 on success and 0 on failure.

SSL_CTX_set_domain_flags() fails if called with a set of flags which are inconsistent or which cannot be supported given the current environment.

SSL_CTX_set_domain_flags() and SSL_CTX_get_domain_flags() fail if called on a SSL_CTX which is not using a QUIC SSL_METHOD.

SSL_get_domain_flags() fails if called on a non-QUIC SSL object.