SSL_want(3)

SSL_want(3) | OpenSSL | SSL_want(3)

# NAME

SSL_want, SSL_want_nothing, SSL_want_read, SSL_want_write, SSL_want_x509_lookup, SSL_want_async, SSL_want_async_job, SSL_want_client_hello_cb - obtain state information TLS/SSL I/O operation

# LIBRARY

libcrypto, -lcrypto

# SYNOPSIS

     #include <openssl/ssl.h>

     int SSL_want(const SSL *ssl);
     int SSL_want_nothing(const SSL *ssl);
     int SSL_want_read(const SSL *ssl);
     int SSL_want_write(const SSL *ssl);
     int SSL_want_x509_lookup(const SSL *ssl);
     int SSL_want_async(const SSL *ssl);
     int SSL_want_async_job(const SSL *ssl);
     int SSL_want_client_hello_cb(const SSL *ssl);

# DESCRIPTION

SSL_want() returns state information for the SSL object ssl.

The other SSL_want_*() calls are shortcuts for the possible states returned by SSL_want().

# NOTES

SSL_want() examines the internal state information of the SSL object. Its return values are similar to that of SSL_get_error(3). Unlike SSL_get_error(3), which also evaluates the error queue, the results are obtained by examining an internal state flag only. The information must therefore only be used for normal operation under non-blocking I/O. Error conditions are not handled and must be treated using SSL_get_error(3).

The result returned by SSL_want() should always be consistent with the result of SSL_get_error(3).

# RETURN VALUES

The following return values can currently occur for SSL_want():

SSL_NOTHING
  There is no data to be written or to be read.
SSL_WRITING
  There are data in the SSL buffer that must be written to the underlying BIO layer in order to complete the actual SSL_*() operation. A call to SSL_get_error(3) should return SSL_ERROR_WANT_WRITE.
SSL_READING
  More data must be read from the underlying BIO layer in order to complete the actual SSL_*() operation. A call to SSL_get_error(3) should return SSL_ERROR_WANT_READ.
SSL_X509_LOOKUP
  The operation did not complete because an application callback set by SSL_CTX_set_client_cert_cb() has asked to be called again. A call to SSL_get_error(3) should return SSL_ERROR_WANT_X509_LOOKUP.
SSL_ASYNC_PAUSED
  An asynchronous operation partially completed and was then paused. See SSL_get_all_async_fds(3). A call to SSL_get_error(3) should return SSL_ERROR_WANT_ASYNC.
SSL_ASYNC_NO_JOBS
  The asynchronous job could not be started because there were no async jobs available in the pool (see ASYNC_init_thread(3)). A call to SSL_get_error(3) should return SSL_ERROR_WANT_ASYNC_JOB.
SSL_CLIENT_HELLO_CB
  The operation did not complete because an application callback set by SSL_CTX_set_client_hello_cb() has asked to be called again. A call to SSL_get_error(3) should return SSL_ERROR_WANT_CLIENT_HELLO_CB.

SSL_want_nothing(), SSL_want_read(), SSL_want_write(), SSL_want_x509_lookup(), SSL_want_async(), SSL_want_async_job(), and SSL_want_client_hello_cb() return 1, when the corresponding condition is true or 0 otherwise.

# SEE ALSO

ssl(7), SSL_get_error(3)

# HISTORY

The SSL_want_client_hello_cb() function and the SSL_CLIENT_HELLO_CB return value were added in OpenSSL 1.1.1.

# COPYRIGHT

Copyright 2001-2017 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the OpenSSL license (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>.

2019-03-12 | 1.1.1c