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Diffstat (limited to 'crypto/openssl/doc/ssl/SSL_read.pod')
| -rw-r--r-- | crypto/openssl/doc/ssl/SSL_read.pod | 118 |
1 files changed, 0 insertions, 118 deletions
diff --git a/crypto/openssl/doc/ssl/SSL_read.pod b/crypto/openssl/doc/ssl/SSL_read.pod deleted file mode 100644 index f6c37f77e491..000000000000 --- a/crypto/openssl/doc/ssl/SSL_read.pod +++ /dev/null @@ -1,118 +0,0 @@ -=pod - -=head1 NAME - -SSL_read - read bytes from a TLS/SSL connection. - -=head1 SYNOPSIS - - #include <openssl/ssl.h> - - int SSL_read(SSL *ssl, void *buf, int num); - -=head1 DESCRIPTION - -SSL_read() tries to read B<num> bytes from the specified B<ssl> into the -buffer B<buf>. - -=head1 NOTES - -If necessary, SSL_read() will negotiate a TLS/SSL session, if -not already explicitly performed by L<SSL_connect(3)|SSL_connect(3)> or -L<SSL_accept(3)|SSL_accept(3)>. If the -peer requests a re-negotiation, it will be performed transparently during -the SSL_read() operation. The behaviour of SSL_read() depends on the -underlying BIO. - -For the transparent negotiation to succeed, the B<ssl> must have been -initialized to client or server mode. This is being done by calling -L<SSL_set_connect_state(3)|SSL_set_connect_state(3)> or SSL_set_accept_state() -before the first call to an SSL_read() or L<SSL_write(3)|SSL_write(3)> -function. - -SSL_read() works based on the SSL/TLS records. The data are received in -records (with a maximum record size of 16kB for SSLv3/TLSv1). Only when a -record has been completely received, it can be processed (decryption and -check of integrity). Therefore data that was not retrieved at the last -call of SSL_read() can still be buffered inside the SSL layer and will be -retrieved on the next call to SSL_read(). If B<num> is higher than the -number of bytes buffered, SSL_read() will return with the bytes buffered. -If no more bytes are in the buffer, SSL_read() will trigger the processing -of the next record. Only when the record has been received and processed -completely, SSL_read() will return reporting success. At most the contents -of the record will be returned. As the size of an SSL/TLS record may exceed -the maximum packet size of the underlying transport (e.g. TCP), it may -be necessary to read several packets from the transport layer before the -record is complete and SSL_read() can succeed. - -If the underlying BIO is B<blocking>, SSL_read() will only return, once the -read operation has been finished or an error occurred, except when a -renegotiation take place, in which case a SSL_ERROR_WANT_READ may occur. -This behaviour can be controlled with the SSL_MODE_AUTO_RETRY flag of the -L<SSL_CTX_set_mode(3)|SSL_CTX_set_mode(3)> call. - -If the underlying BIO is B<non-blocking>, SSL_read() will also return -when the underlying BIO could not satisfy the needs of SSL_read() -to continue the operation. In this case a call to -L<SSL_get_error(3)|SSL_get_error(3)> with the -return value of SSL_read() will yield B<SSL_ERROR_WANT_READ> or -B<SSL_ERROR_WANT_WRITE>. As at any time a re-negotiation is possible, a -call to SSL_read() can also cause write operations! The calling process -then must repeat the call after taking appropriate action to satisfy the -needs of SSL_read(). 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. - -=head1 WARNING - -When an SSL_read() operation has to be repeated because of -B<SSL_ERROR_WANT_READ> or B<SSL_ERROR_WANT_WRITE>, it must be repeated -with the same arguments. - -=head1 RETURN VALUES - -The following return values can occur: - -=over 4 - -=item E<gt>0 - -The read operation was successful; the return value is the number of -bytes actually read from the TLS/SSL connection. - -=item 0 - -The read operation was not successful. The reason may either be a clean -shutdown due to a "close notify" alert sent by the peer (in which case -the SSL_RECEIVED_SHUTDOWN flag in the ssl shutdown state is set -(see L<SSL_shutdown(3)|SSL_shutdown(3)>, -L<SSL_set_shutdown(3)|SSL_set_shutdown(3)>). It is also possible, that -the peer simply shut down the underlying transport and the shutdown is -incomplete. Call SSL_get_error() with the return value B<ret> to find out, -whether an error occurred or the connection was shut down cleanly -(SSL_ERROR_ZERO_RETURN). - -SSLv2 (deprecated) does not support a shutdown alert protocol, so it can -only be detected, whether the underlying connection was closed. It cannot -be checked, whether the closure was initiated by the peer or by something -else. - -=item E<lt>0 - -The read operation was not successful, because either an error occurred -or action must be taken by the calling process. Call SSL_get_error() with the -return value B<ret> to find out the reason. - -=back - -=head1 SEE ALSO - -L<SSL_get_error(3)|SSL_get_error(3)>, L<SSL_write(3)|SSL_write(3)>, -L<SSL_CTX_set_mode(3)|SSL_CTX_set_mode(3)>, L<SSL_CTX_new(3)|SSL_CTX_new(3)>, -L<SSL_connect(3)|SSL_connect(3)>, L<SSL_accept(3)|SSL_accept(3)> -L<SSL_set_connect_state(3)|SSL_set_connect_state(3)>, -L<SSL_shutdown(3)|SSL_shutdown(3)>, L<SSL_set_shutdown(3)|SSL_set_shutdown(3)>, -L<ssl(3)|ssl(3)>, L<bio(3)|bio(3)> - -=cut |