=head1 NAME
-SSL_CTX_set_msg_callback, SSL_CTX_set_msg_callback_arg, SSL_set_msg_callback, SSL_set_msg_callback_arg - install callback for observing protocol messages
+SSL_CTX_set_msg_callback,
+SSL_CTX_set_msg_callback_arg,
+SSL_set_msg_callback,
+SSL_set_msg_callback_arg
+- install callback for observing protocol messages
=head1 SYNOPSIS
#include <openssl/ssl.h>
- void SSL_CTX_set_msg_callback(SSL_CTX *ctx, void (*cb)(int write_p, int version, int content_type, const void *buf, size_t len, SSL *ssl, void *arg));
+ void SSL_CTX_set_msg_callback(SSL_CTX *ctx,
+ void (*cb)(int write_p, int version,
+ int content_type, const void *buf,
+ size_t len, SSL *ssl, void *arg));
void SSL_CTX_set_msg_callback_arg(SSL_CTX *ctx, void *arg);
- void SSL_set_msg_callback(SSL *ssl, void (*cb)(int write_p, int version, int content_type, const void *buf, size_t len, SSL *ssl, void *arg));
+ void SSL_set_msg_callback(SSL *ssl,
+ void (*cb)(int write_p, int version,
+ int content_type, const void *buf,
+ size_t len, SSL *ssl, void *arg));
void SSL_set_msg_callback_arg(SSL *ssl, void *arg);
=head1 DESCRIPTION
SSL_CTX_set_msg_callback() or SSL_set_msg_callback() can be used to
define a message callback function I<cb> for observing all SSL/TLS
protocol messages (such as handshake messages) that are received or
-sent. SSL_CTX_set_msg_callback_arg() and SSL_set_msg_callback_arg()
+sent, as well as other events that occur during processing.
+SSL_CTX_set_msg_callback_arg() and SSL_set_msg_callback_arg()
can be used to set argument I<arg> to the callback function, which is
available for arbitrary application use.
default settings that will be copied to new B<SSL> objects by
L<SSL_new(3)>. SSL_set_msg_callback() and
SSL_set_msg_callback_arg() modify the actual settings of an B<SSL>
-object. Using a B<0> pointer for I<cb> disables the message callback.
+object. Using a B<NULL> pointer for I<cb> disables the message callback.
-When I<cb> is called by the SSL/TLS library for a protocol message,
-the function arguments have the following meaning:
+When I<cb> is called by the SSL/TLS library the function arguments have the
+following meaning:
=over 4
=item I<version>
The protocol version according to which the protocol message is
-interpreted by the library. Currently, this is one of
-B<SSL2_VERSION>, B<SSL3_VERSION> and B<TLS1_VERSION> (for SSL 2.0, SSL
-3.0 and TLS 1.0, respectively).
+interpreted by the library such as B<TLS1_3_VERSION>, B<TLS1_2_VERSION> etc.
+This is set to 0 for the SSL3_RT_HEADER pseudo content type (see NOTES below).
=item I<content_type>
-In the case of SSL 2.0, this is always B<0>. In the case of SSL 3.0
-or TLS 1.0, this is one of the B<ContentType> values defined in the
-protocol specification (B<change_cipher_spec(20)>, B<alert(21)>,
-B<handshake(22)>; but never B<application_data(23)> because the
-callback will only be called for protocol messages).
+This is one of the content type values defined in the protocol specification
+(B<SSL3_RT_CHANGE_CIPHER_SPEC>, B<SSL3_RT_ALERT>, B<SSL3_RT_HANDSHAKE>; but never
+B<SSL3_RT_APPLICATION_DATA> because the callback will only be called for protocol
+messages). Alternatively it may be a "pseudo" content type. These pseudo
+content types are used to signal some other event in the processing of data (see
+NOTES below).
=item I<buf>, I<len>
-I<buf> points to a buffer containing the protocol message, which
-consists of I<len> bytes. The buffer is no longer valid after the
-callback function has returned.
+I<buf> points to a buffer containing the protocol message or other data (in the
+case of pseudo content types), which consists of I<len> bytes. The buffer is no
+longer valid after the callback function has returned.
=item I<ssl>
a TLS 1.0 ClientHello message is received by an SSL 3.0-only server,
I<version> will be B<SSL3_VERSION>.
+Pseudo content type values may be sent at various points during the processing
+of data. The following pseudo content types are currently defined:
+
+=over 4
+
+=item B<SSL3_RT_HEADER>
+
+Used when a record is sent or received. The B<buf> contains the record header
+bytes only.
+
+=item B<SSL3_RT_INNER_CONTENT_TYPE>
+
+Used when an encrypted TLSv1.3 record is sent or received. In encrypted TLSv1.3
+records the content type in the record header is always
+SSL3_RT_APPLICATION_DATA. The real content type for the record is contained in
+an "inner" content type. B<buf> contains the encoded "inner" content type byte.
+
+=back
+
+=head1 RETURN VALUES
+
+SSL_CTX_set_msg_callback(), SSL_CTX_set_msg_callback_arg(), SSL_set_msg_callback()
+and SSL_set_msg_callback_arg() do not return values.
+
=head1 SEE ALSO
-L<ssl(3)>, L<SSL_new(3)>
+L<ssl(7)>, L<SSL_new(3)>
+
+=head1 HISTORY
+
+The pseudo content type B<SSL3_RT_INNER_CONTENT_TYPE> was added in OpenSSL 1.1.1.
=head1 COPYRIGHT
-Copyright 2001-2016 The OpenSSL Project Authors. All Rights Reserved.
+Copyright 2001-2018 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>.
projects / openssl.git / blobdiff