SSL_CTX_SET_MSG_CALLBACK(3SSL) | OpenSSL | SSL_CTX_SET_MSG_CALLBACK(3SSL) |
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
#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_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_arg(SSL *ssl, void *arg);
SSL_CTX_set_msg_callback() or SSL_set_msg_callback() can be used to define a message callback function cb for observing all SSL/TLS protocol messages (such as handshake messages) that are received or 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 arg to the callback function, which is available for arbitrary application use.
SSL_CTX_set_msg_callback() and SSL_CTX_set_msg_callback_arg() specify default settings that will be copied to new SSL objects by SSL_new(3). SSL_set_msg_callback() and SSL_set_msg_callback_arg() modify the actual settings of an SSL object. Using a NULL pointer for cb disables the message callback.
When cb is called by the SSL/TLS library the function arguments have the following meaning:
Protocol messages are passed to the callback function after decryption and fragment collection where applicable. (Thus record boundaries are not visible.)
If processing a received protocol message results in an error, the callback function may not be called. For example, the callback function will never see messages that are considered too large to be processed.
Due to automatic protocol version negotiation, version is not necessarily the protocol version used by the sender of the message: If a TLS 1.0 ClientHello message is received by an SSL 3.0-only server, version will be 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:
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.
The pseudo content type SSL3_RT_INNER_CONTENT_TYPE was added in OpenSSL 1.1.1.
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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 <https://www.openssl.org/source/license.html>.
2023-10-23 | 3.0.11 |