159191Skris=pod 259191Skris 359191Skris=head1 NAME 459191Skris 568651SkrisSSL_get_error - obtain result code for TLS/SSL I/O operation 659191Skris 759191Skris=head1 SYNOPSIS 859191Skris 959191Skris #include <openssl/ssl.h> 1059191Skris 11160814Ssimon int SSL_get_error(const SSL *ssl, int ret); 1259191Skris 1359191Skris=head1 DESCRIPTION 1459191Skris 1559191SkrisSSL_get_error() returns a result code (suitable for the C "switch" 16100936Snectarstatement) for a preceding call to SSL_connect(), SSL_accept(), SSL_do_handshake(), 1772613SkrisSSL_read(), SSL_peek(), or SSL_write() on B<ssl>. The value returned by 1872613Skristhat TLS/SSL I/O function must be passed to SSL_get_error() in parameter 1959191SkrisB<ret>. 2059191Skris 2159191SkrisIn addition to B<ssl> and B<ret>, SSL_get_error() inspects the 2259191Skriscurrent thread's OpenSSL error queue. Thus, SSL_get_error() must be 2368651Skrisused in the same thread that performed the TLS/SSL I/O operation, and no 2459191Skrisother OpenSSL function calls should appear in between. The current 2568651Skristhread's error queue must be empty before the TLS/SSL I/O operation is 2659191Skrisattempted, or SSL_get_error() will not work reliably. 2759191Skris 2859191Skris=head1 RETURN VALUES 2959191Skris 3059191SkrisThe following return values can currently occur: 3159191Skris 3259191Skris=over 4 3359191Skris 3459191Skris=item SSL_ERROR_NONE 3559191Skris 3668651SkrisThe TLS/SSL I/O operation completed. This result code is returned 3759191Skrisif and only if B<ret E<gt> 0>. 3859191Skris 3959191Skris=item SSL_ERROR_ZERO_RETURN 4059191Skris 4168651SkrisThe TLS/SSL connection has been closed. If the protocol version is SSL 3.0 4259191Skrisor TLS 1.0, this result code is returned only if a closure 4368651Skrisalert has occurred in the protocol, i.e. if the connection has been 4468651Skrisclosed cleanly. Note that in this case B<SSL_ERROR_ZERO_RETURN> 4568651Skrisdoes not necessarily indicate that the underlying transport 4668651Skrishas been closed. 4759191Skris 4859191Skris=item SSL_ERROR_WANT_READ, SSL_ERROR_WANT_WRITE 4959191Skris 5068651SkrisThe operation did not complete; the same TLS/SSL I/O function should be 5172613Skriscalled again later. If, by then, the underlying B<BIO> has data 5272613Skrisavailable for reading (if the result code is B<SSL_ERROR_WANT_READ>) 5372613Skrisor allows writing data (B<SSL_ERROR_WANT_WRITE>), then some TLS/SSL 5472613Skrisprotocol progress will take place, i.e. at least part of an TLS/SSL 5572613Skrisrecord will be read or written. Note that the retry may again lead to 5672613Skrisa B<SSL_ERROR_WANT_READ> or B<SSL_ERROR_WANT_WRITE> condition. 5772613SkrisThere is no fixed upper limit for the number of iterations that 5872613Skrismay be necessary until progress becomes visible at application 5972613Skrisprotocol level. 6059191Skris 6172613SkrisFor socket B<BIO>s (e.g. when SSL_set_fd() was used), select() or 6272613Skrispoll() on the underlying socket can be used to find out when the 6372613SkrisTLS/SSL I/O function should be retried. 6472613Skris 6568651SkrisCaveat: Any TLS/SSL I/O function can lead to either of 6672613SkrisB<SSL_ERROR_WANT_READ> and B<SSL_ERROR_WANT_WRITE>. In particular, 6772613SkrisSSL_read() or SSL_peek() may want to write data and SSL_write() may want 6872613Skristo read data. This is mainly because TLS/SSL handshakes may occur at any 6972613Skristime during the protocol (initiated by either the client or the server); 7072613SkrisSSL_read(), SSL_peek(), and SSL_write() will handle any pending handshakes. 7159191Skris 7289837Skris=item SSL_ERROR_WANT_CONNECT, SSL_ERROR_WANT_ACCEPT 7379998Skris 7479998SkrisThe operation did not complete; the same TLS/SSL I/O function should be 7579998Skriscalled again later. The underlying BIO was not connected yet to the peer 7689837Skrisand the call would block in connect()/accept(). The SSL function should be 7789837Skriscalled again when the connection is established. These messages can only 7889837Skrisappear with a BIO_s_connect() or BIO_s_accept() BIO, respectively. 7979998SkrisIn order to find out, when the connection has been successfully established, 8079998Skrison many platforms select() or poll() for writing on the socket file descriptor 8179998Skriscan be used. 8279998Skris 8359191Skris=item SSL_ERROR_WANT_X509_LOOKUP 8459191Skris 8559191SkrisThe operation did not complete because an application callback set by 8659191SkrisSSL_CTX_set_client_cert_cb() has asked to be called again. 8768651SkrisThe TLS/SSL I/O function should be called again later. 8859191SkrisDetails depend on the application. 8959191Skris 9059191Skris=item SSL_ERROR_SYSCALL 9159191Skris 9259191SkrisSome I/O error occurred. The OpenSSL error queue may contain more 9359191Skrisinformation on the error. If the error queue is empty 9459191Skris(i.e. ERR_get_error() returns 0), B<ret> can be used to find out more 9559191Skrisabout the error: If B<ret == 0>, an EOF was observed that violates 9659191Skristhe protocol. If B<ret == -1>, the underlying B<BIO> reported an 9759191SkrisI/O error (for socket I/O on Unix systems, consult B<errno> for details). 9859191Skris 9959191Skris=item SSL_ERROR_SSL 10059191Skris 10159191SkrisA failure in the SSL library occurred, usually a protocol error. The 10259191SkrisOpenSSL error queue contains more information on the error. 10359191Skris 10459191Skris=back 10559191Skris 10659191Skris=head1 SEE ALSO 10759191Skris 10859191SkrisL<ssl(3)|ssl(3)>, L<err(3)|err(3)> 10959191Skris 11059191Skris=head1 HISTORY 11159191Skris 11259191SkrisSSL_get_error() was added in SSLeay 0.8. 11359191Skris 11459191Skris=cut 115