Add the ability to configure anti-replay via SSL_CONF

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

diff --git a/doc/man3/SSL_connect.pod b/doc/man3/SSL_connect.pod
index 1f054d676775e6b53712a1e5d96f90286ab0ede7..426b8ad757dbd1d57e54b95f6a6f767a2e425f55 100644 (file)
--- a/doc/man3/SSL_connect.pod
+++ b/doc/man3/SSL_connect.pod
@@ -35,6 +35,21 @@ 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.
 
+Many systems implement Nagle's algorithm by default which means that it will
+buffer outgoing TCP data if a TCP packet has already been sent for which no
+corresponding ACK has been received yet from the peer. This can have performance
+impacts after a successful TLSv1.3 handshake or a successful TLSv1.2 (or below)
+resumption handshake, because the last peer to communicate in the handshake is
+the client. If the client is also the first to send application data (as is
+typical for many protocols) then this data could be buffered until an ACK has
+been received for the final handshake message.
+
+The B<TCP_NODELAY> socket option is often available to disable Nagle's
+algorithm. If an application opts to disable Nagle's algorithm consideration
+should be given to turning it back on again later if appropriate. The helper
+function BIO_set_tcp_ndelay() can be used to turn on or off the B<TCP_NODELAY>
+option.
+
 =head1 RETURN VALUES
 
 The following return values can occur:
@@ -72,7 +87,7 @@ L<SSL_CTX_new(3)>
 
 =head1 COPYRIGHT
 
-Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
+Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved.
 
 Licensed under the OpenSSL license (the "License").  You may not use
 this file except in compliance with the License.  You can obtain a copy