SSL_connect(3) OpenSSL SSL_connect(3)NAMESSL_connect - initiate the TLS/SSL handshake with an TLS/SSL server
SYNOPSIS
#include <openssl/ssl.h>
int SSL_connect(SSL *ssl);
DESCRIPTIONSSL_connect() initiates the TLS/SSL handshake with a server. The commu‐
nication channel must already have been set and assigned to the ssl by
setting an underlying BIO.
NOTES
The behaviour of SSL_connect() depends on the underlying BIO.
If the underlying BIO is blocking, SSL_connect() will only return once
the handshake has been finished or an error occurred.
If the underlying BIO is non-blocking, SSL_connect() will also return
when the underlying BIO could not satisfy the needs of SSL_connect() to
continue the handshake, indicating the problem by the return value -1.
In this case a call to SSL_get_error() with the return value of
SSL_connect() will yield SSL_ERROR_WANT_READ or SSL_ERROR_WANT_WRITE.
The calling process then must repeat the call after taking appropriate
action to satisfy the needs of SSL_connect(). The action depends on
the underlying BIO. When using a non-blocking socket, nothing is to be
done, but select() can be used to check for the required condition.
When using a buffering BIO, like a BIO pair, data must be written into
or retrieved out of the BIO before being able to continue.
RETURN VALUES
The following return values can occur:
1 The TLS/SSL handshake was successfully completed, a TLS/SSL connec‐
tion has been established.
0 The TLS/SSL handshake was not successful but was shut down con‐
trolled and by the specifications of the TLS/SSL protocol. Call
SSL_get_error() with the return value ret to find out the reason.
<0 The TLS/SSL handshake was not successful, because a fatal error
occurred either at the protocol level or a connection failure
occurred. The shutdown was not clean. It can also occur of action
is need to continue the operation for non-blocking BIOs. Call
SSL_get_error() with the return value ret to find out the reason.
SEE ALSOSSL_get_error(3), SSL_accept(3), SSL_shutdown(3), ssl(3), bio(3),
SSL_set_connect_state(3), SSL_do_handshake(3), SSL_CTX_new(3)0.9.8k 2009-05-20 SSL_connect(3)
