diff options
Diffstat (limited to 'deps/openssl/openssl/doc/ssl/SSL_pending.pod')
-rw-r--r-- | deps/openssl/openssl/doc/ssl/SSL_pending.pod | 65 |
1 files changed, 44 insertions, 21 deletions
diff --git a/deps/openssl/openssl/doc/ssl/SSL_pending.pod b/deps/openssl/openssl/doc/ssl/SSL_pending.pod index 9dd071b625..f6ed5652a1 100644 --- a/deps/openssl/openssl/doc/ssl/SSL_pending.pod +++ b/deps/openssl/openssl/doc/ssl/SSL_pending.pod @@ -2,44 +2,67 @@ =head1 NAME -SSL_pending - obtain number of readable bytes buffered in an SSL object +SSL_pending, SSL_has_pending - check for readable bytes buffered in an +SSL object =head1 SYNOPSIS #include <openssl/ssl.h> int SSL_pending(const SSL *ssl); + int SSL_has_pending(const SSL *s); =head1 DESCRIPTION -SSL_pending() returns the number of bytes which are available inside -B<ssl> for immediate read. +Data is received in whole blocks known as records from the peer. A whole record +is processed (e.g. decrypted) in one go and is buffered by OpenSSL until it is +read by the application via a call to L<SSL_read(3)>. + +SSL_pending() returns the number of bytes which have been processed, buffered +and are available inside B<ssl> for immediate read. + +If the B<SSL> object's I<read_ahead> flag is set (see +L<SSL_CTX_set_read_ahead(3)>), additional protocol bytes (beyond the current +record) may have been read containing more TLS/SSL records. This also applies to +DTLS and pipelining (see L<SSL_CTX_set_split_send_fragment(3)>). These +additional bytes will be buffered by OpenSSL but will remain unprocessed until +they are needed. As these bytes are still in an unprocessed state SSL_pending() +will ignore them. Therefore it is possible for no more bytes to be readable from +the underlying BIO (because OpenSSL has already read them) and for SSL_pending() +to return 0, even though readable application data bytes are available (because +the data is in unprocessed buffered records). + +SSL_has_pending() returns 1 if B<s> has buffered data (whether processed or +unprocessed) and 0 otherwise. Note that it is possible for SSL_has_pending() to +return 1, and then a subsequent call to SSL_read() to return no data because the +unprocessed buffered data when processed yielded no application data (for +example this can happen during renegotiation). It is also possible in this +scenario for SSL_has_pending() to continue to return 1 even after an SSL_read() +call because the buffered and unprocessed data is not yet processable (e.g. +because OpenSSL has only received a partial record so far). -=head1 NOTES +=head1 RETURN VALUES -Data are received in blocks from the peer. Therefore data can be buffered -inside B<ssl> and are ready for immediate retrieval with -L<SSL_read(3)|SSL_read(3)>. +SSL_pending() returns the number of buffered and processed application data +bytes that are pending and are available for immediate read. SSL_has_pending() +returns 1 if there is buffered record data in the SSL object and 0 otherwise. -=head1 RETURN VALUES +=head1 SEE ALSO -The number of bytes pending is returned. +L<SSL_read(3)>, L<SSL_CTX_set_read_ahead(3)>, +L<SSL_CTX_set_split_send_fragment(3)>, L<ssl(3)> -=head1 BUGS +=head1 HISTORY -SSL_pending() takes into account only bytes from the TLS/SSL record -that is currently being processed (if any). If the B<SSL> object's -I<read_ahead> flag is set (see -L<SSL_CTX_set_read_ahead(3)|SSL_CTX_set_read_ahead(3)>), additional protocol -bytes may have been read containing more TLS/SSL records; these are ignored by -SSL_pending(). +The SSL_has_pending() function was added in OpenSSL 1.1.0. -Up to OpenSSL 0.9.6, SSL_pending() does not check if the record type -of pending data is application data. +=head1 COPYRIGHT -=head1 SEE ALSO +Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved. -L<SSL_read(3)|SSL_read(3)>, -L<SSL_CTX_set_read_ahead(3)|SSL_CTX_set_read_ahead(3)>, L<ssl(3)|ssl(3)> +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 +L<https://www.openssl.org/source/license.html>. =cut |