Rename OSSL_SERIALIZER / OSSL_DESERIALIZER to OSSL_ENCODE / OSSL_DECODE

[openssl.git] / doc / man3 / SSL_CTX_set_read_ahead.pod

diff --git a/doc/man3/SSL_CTX_set_read_ahead.pod b/doc/man3/SSL_CTX_set_read_ahead.pod
index 3a96ce3ca652a6f2476c6a0a61cd8fe57f592b08..c2fc6fd7dc8e573f9d30e8f94c5bf485048c9d73 100644 (file)
--- a/doc/man3/SSL_CTX_set_read_ahead.pod
+++ b/doc/man3/SSL_CTX_set_read_ahead.pod
@@ -21,16 +21,18 @@ SSL_CTX_get_default_read_ahead
 =head1 DESCRIPTION
 
 SSL_CTX_set_read_ahead() and SSL_set_read_ahead() set whether we should read as
-many input bytes as possible (for non-blocking reads) or not. For example if
+many input bytes as possible (for nonblocking reads) or not. For example if
 B<x> bytes are currently required by OpenSSL, but B<y> bytes are available from
 the underlying BIO (where B<y> > B<x>), then OpenSSL will read all B<y> bytes
 into its buffer (providing that the buffer is large enough) if reading ahead is
-on, or B<x> bytes otherwise. The parameter B<yes> or B<m> should be 0 to ensure
-reading ahead is off, or non zero otherwise.
+on, or B<x> bytes otherwise.
+Setting the parameter B<yes> to 0 turns reading ahead is off, other values turn
+it on.
 SSL_CTX_set_default_read_ahead() is identical to SSL_CTX_set_read_ahead().
 
 SSL_CTX_get_read_ahead() and SSL_get_read_ahead() indicate whether reading
 ahead has been set or not.
+SSL_CTX_get_default_read_ahead() is identical to SSL_CTX_get_read_ahead().
 
 =head1 NOTES
 
@@ -39,6 +41,18 @@ SSL_CTX_get_read_head() and SSL_get_read_ahead() are undefined for DTLS. Setting
 B<read_ahead> can impact the behaviour of the SSL_pending() function
 (see L<SSL_pending(3)>).
 
+Since SSL_read() can return B<SSL_ERROR_WANT_READ> for non-application data
+records, and SSL_has_pending() can't tell the difference between processed and
+unprocessed data, it's recommended that if read ahead is turned on that
+B<SSL_MODE_AUTO_RETRY> is not turned off using SSL_CTX_clear_mode().
+That will prevent getting B<SSL_ERROR_WANT_READ> when there is still a complete
+record available that hasn't been processed.
+
+If the application wants to continue to use the underlying transport (e.g. TCP
+connection) after the SSL connection is finished using SSL_shutdown() reading
+ahead should be turned off.
+Otherwise the SSL structure might read data that it shouldn't.
+
 =head1 RETURN VALUES
 
 SSL_get_read_ahead() and SSL_CTX_get_read_ahead() return 0 if reading ahead is off,
@@ -50,9 +64,9 @@ L<ssl(7)>, L<SSL_pending(3)>
 
 =head1 COPYRIGHT
 
-Copyright 2015-2016 The OpenSSL Project Authors. All Rights Reserved.
+Copyright 2015-2020 The OpenSSL Project Authors. All Rights Reserved.
 
-Licensed under the OpenSSL license (the "License").  You may not use
+Licensed under the Apache License 2.0 (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>.