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/**************************************************************************/
/* */
/* Copyright (c) Microsoft Corporation. All rights reserved. */
/* */
/* This software is licensed under the Microsoft Software License */
/* Terms for Microsoft Azure RTOS. Full text of the license can be */
/* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
/* and in the root directory of this software. */
/* */
/**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/** */
/** NetX Secure Component */
/** */
/** Datagram Transport Layer Security (DTLS) */
/** */
/**************************************************************************/
/**************************************************************************/
#define NX_SECURE_SOURCE_CODE
#include "nx_secure_dtls.h"
#ifdef NX_SECURE_ENABLE_DTLS
#include "nx_packet.h"
#include "nx_udp.h"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_secure_dtls_client_handshake PORTABLE C */
/* 6.1.10 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function runs the DTLS Client mode state machine. It processes */
/* an incoming handshake record and takes appropriate action to */
/* advance the DTLS Client handshake. */
/* */
/* INPUT */
/* */
/* dtls_session DTLS control block */
/* packet_buffer Pointer into record buffer */
/* data_length Length of data */
/* wait_option Controls timeout actions */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _nx_secure_dtls_allocate_handshake_packet */
/* Allocate DTLS handshake packet*/
/* _nx_secure_dtls_packet_allocate Allocate internal DTLS packet */
/* _nx_secure_dtls_process_handshake_header */
/* Process handshake header */
/* _nx_secure_dtls_process_helloverifyrequest */
/* Process HelloVerifyRequest */
/* _nx_secure_dtls_retransmit_queue_flush */
/* Flush retransmit queue */
/* _nx_secure_dtls_send_clienthello Send ClientHello */
/* _nx_secure_dtls_send_handshake_record Send DTLS handshake record */
/* _nx_secure_dtls_send_record Send DTLS records */
/* _nx_secure_tls_generate_keys Generate session keys */
/* _nx_secure_tls_generate_premaster_secret */
/* Generate premaster secret */
/* _nx_secure_tls_handshake_hash_update Update Finished hash */
/* _nx_secure_tls_map_error_to_alert Map internal error to alert */
/* _nx_secure_tls_process_certificate_request */
/* Process certificate request */
/* _nx_secure_tls_process_finished Process Finished message */
/* _nx_secure_tls_process_remote_certificate */
/* Process remote certificate */
/* _nx_secure_tls_process_server_key_exchange */
/* Process ServerKeyExchange */
/* _nx_secure_tls_process_serverhello Process ServerHello */
/* _nx_secure_tls_send_alert Send DTLS alert */
/* _nx_secure_tls_send_certificate Send DTLS certificate */
/* _nx_secure_tls_send_certificate_verify */
/* Send certificate verify */
/* _nx_secure_tls_send_changecipherspec Send ChangeCipherSpec */
/* _nx_secure_tls_send_client_key_exchange */
/* Send ClientKeyExchange */
/* _nx_secure_tls_send_finished Send Finished message */
/* _nx_secure_tls_session_keys_set Set session keys */
/* nx_secure_tls_packet_release Release packet */
/* tx_mutex_get Get protection mutex */
/* tx_mutex_put Put protection mutex */
/* */
/* CALLED BY */
/* */
/* _nx_secure_dtls_process_record Process DTLS record data */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* verified memcpy use cases, */
/* verified memmove use cases, */
/* released packet securely, */
/* fixed certificate buffer */
/* allocation, */
/* resulting in version 6.1 */
/* 12-31-2020 Timothy Stapko Modified comment(s), */
/* improved buffer length */
/* verification, added null */
/* pointer checking, */
/* resulting in version 6.1.3 */
/* 01-31-2022 Timothy Stapko Modified comment(s), */
/* fixed out-of-order handling,*/
/* resulting in version 6.1.10 */
/* */
/**************************************************************************/
UINT _nx_secure_dtls_client_handshake(NX_SECURE_DTLS_SESSION *dtls_session, UCHAR *packet_buffer,
UINT data_length, ULONG wait_option)
{
#ifndef NX_SECURE_TLS_CLIENT_DISABLED
UINT status;
USHORT message_type = NX_SECURE_TLS_INVALID_MESSAGE;
UINT header_bytes;
UINT message_length;
UCHAR *data_start = NX_NULL;
NX_PACKET *send_packet = NX_NULL;
NX_PACKET_POOL *packet_pool;
UINT error_number;
UINT alert_number;
UINT alert_level;
UINT message_seq;
UINT fragment_offset;
UINT fragment_length;
UCHAR *fragment_buffer;
NX_SECURE_TLS_SESSION *tls_session;
/* Basic state machine for handshake:
* 1. We have received a handshake message, now process the header.
* 2. Then process the message itself and populate the TLS socket structure.
* 3. Follow up with whatever actions are needed.
*/
/* Get a reference to the internal TLS state for ease of use. */
tls_session = &dtls_session -> nx_secure_dtls_tls_session;
/* Use the TLS packet buffer for fragment processing. */
fragment_buffer = tls_session->nx_secure_tls_packet_buffer;
while (data_length > 0)
{
header_bytes = data_length;
/* First, process the handshake message to get our state and any data therein. */
status = _nx_secure_dtls_process_handshake_header(packet_buffer, &message_type, &header_bytes,
&message_length, &message_seq, &fragment_offset, &fragment_length);
if (status == NX_SUCCESS)
{
/* Out-of-order plus fragmentation:
* - If message sequence > current message sequence
* - New message
* - If message_sequence <= current message sequence
* - If fragment_length < message length, we have a fragment
* - Once fragment is reassembled, check message sequence for repeats
*/
/* If we see a repeated message sequence, assume an unnecessary retransmission and ignore. */
if (message_seq < dtls_session -> nx_secure_dtls_remote_handshake_sequence)
{
/* Re-transmitted message. */
return(NX_SUCCESS);
}
/* Check the fragment_length with the lenght of packet buffer. */
if ((header_bytes + fragment_length) > data_length)
{
return(NX_SECURE_TLS_INCORRECT_MESSAGE_LENGTH);
}
/* Check available area of buffer. */
if ((fragment_offset + fragment_length) > tls_session -> nx_secure_tls_packet_buffer_size ||
(header_bytes + message_length) > tls_session -> nx_secure_tls_packet_buffer_size)
{
return(NX_SECURE_TLS_PACKET_BUFFER_TOO_SMALL);
}
/* If this message sequence isn't what we expect, continue reading packets. */
if(message_seq != dtls_session -> nx_secure_dtls_expected_handshake_sequence)
{
return(NX_SECURE_TLS_OUT_OF_ORDER_MESSAGE);
}
/* If we have a new sequence number, we have a new record (may be fragmented). Unless
the sequence number is 0, which means it is the first record. */
if (message_seq > dtls_session -> nx_secure_dtls_remote_handshake_sequence || (message_seq == 0 && fragment_offset == 0))
{
/* New record starting, reset the fragment length and handshake sequence number. */
dtls_session -> nx_secure_dtls_remote_handshake_sequence = message_seq;
dtls_session -> nx_secure_dtls_fragment_length = message_length;
}
if (fragment_length > dtls_session -> nx_secure_dtls_fragment_length)
{
return(NX_SECURE_TLS_INVALID_PACKET);
}
/* When we receive a message fragment, subtract it from the current fragment length. */
dtls_session -> nx_secure_dtls_fragment_length -= fragment_length;
/* Copy the fragment data (minus the header) into the reassembly buffer. */
NX_SECURE_MEMCPY(&fragment_buffer[fragment_offset], &packet_buffer[header_bytes], fragment_length); /* Use case of memcpy is verified. */
/* If we still have fragments to add, just return success. */
if (dtls_session -> nx_secure_dtls_fragment_length > 0)
{
return(NX_SUCCESS);
}
else
{
/* At beginning of handshake, reset the expected sequence number. */
if (message_seq == 0)
{
dtls_session -> nx_secure_dtls_expected_handshake_sequence = 0;
}
/* If the recontructed message has a sequence not equal to the expected, it's
a retransmission we need to ignore. */
if (message_seq != dtls_session -> nx_secure_dtls_expected_handshake_sequence)
{
return(NX_SUCCESS);
}
/* Our next expected handshake message sequence number is 1 greater than this one. */
dtls_session -> nx_secure_dtls_expected_handshake_sequence = message_seq + 1;
/* Put the header into the packet buffer, adjusting the fields to create a seam-less
* DTLS record. */
NX_SECURE_MEMMOVE(&fragment_buffer[header_bytes], fragment_buffer, message_length); /* Use case of memmove is verified. */
/* Reconstruct the header in the fragment buffer so we can hash the
reconstructed record as if it were never fragmented. */
/* Type. */
fragment_buffer[0] = (UCHAR)message_type;
/* Length. */
fragment_buffer[1] = (UCHAR)(message_length >> 16);
fragment_buffer[2] = (UCHAR)(message_length >> 8);
fragment_buffer[3] = (UCHAR)(message_length);
/* Sequence. */
fragment_buffer[4] = (UCHAR)(message_seq >> 8);
fragment_buffer[5] = (UCHAR)(message_seq);
/* Fragment offset is now 0. */
fragment_buffer[6] = 0;
fragment_buffer[7] = 0;
fragment_buffer[8] = 0;
/* Fragment length is now == message length. */
fragment_buffer[9] = (UCHAR)(message_length >> 16);
fragment_buffer[10] = (UCHAR)(message_length >> 8);
fragment_buffer[11] = (UCHAR)(message_length);
/* We have a reassembled DTLS record, use that for the handshake. */
data_start = fragment_buffer;
}
}
if (status != NX_SECURE_TLS_SUCCESS)
{
return(status);
}
/* Allocate a packet for all send operations. */
packet_pool = tls_session -> nx_secure_tls_packet_pool;
/* Hash this handshake message. We do not hash HelloRequest messages.
Hashes include the handshake layer header but not the record layer header. */
if (message_type != NX_SECURE_TLS_HELLO_REQUEST && message_type != NX_SECURE_TLS_FINISHED &&
message_type != NX_SECURE_TLS_HELLO_VERIFY_REQUEST)
{
_nx_secure_tls_handshake_hash_update(tls_session, data_start, message_length + header_bytes);
}
/* Reduce total length by the size of this fragment. */
data_length -= (fragment_length + header_bytes);
data_start += header_bytes;
/* Process the message itself information from the header. */
switch (message_type)
{
case NX_SECURE_TLS_HELLO_VERIFY_REQUEST:
/* Initial DTLS message from server, contains a cookie for later transmissions. */
status = _nx_secure_dtls_process_helloverifyrequest(dtls_session, data_start, message_length);
if (status)
{
/* This is the end of a flight, clear out the transmit queue. */
_nx_secure_dtls_retransmit_queue_flush(dtls_session);
}
break;
case NX_SECURE_TLS_SERVER_HELLO:
/* Server has responded to our ClientHello. */
status = _nx_secure_tls_process_serverhello(tls_session, data_start, message_length);
break;
case NX_SECURE_TLS_CERTIFICATE_MSG:
/* Server has sent its certificate message. */
status = _nx_secure_tls_process_remote_certificate(tls_session, data_start, message_length, message_length);
break;
case NX_SECURE_TLS_SERVER_HELLO_DONE:
/* Server has responded to our ClientHello. */
/* A ServerHelloDone does not contain any data - it simply changes state. */
tls_session -> nx_secure_tls_client_state = NX_SECURE_TLS_CLIENT_STATE_SERVERHELLO_DONE;
/* This is the end of a flight, clear out the transmit queue. */
_nx_secure_dtls_retransmit_queue_flush(dtls_session);
break;
case NX_SECURE_TLS_SERVER_KEY_EXCHANGE:
/* Server has sent a key exchange message, used for certain ciphersuites (DH and PSK mainly). */
status = _nx_secure_tls_process_server_key_exchange(tls_session, data_start, message_length);
break;
case NX_SECURE_TLS_CERTIFICATE_REQUEST:
/* Server has requested we provide a client certificate. */
status = _nx_secure_tls_process_certificate_request(tls_session, data_start, message_length);
break;
case NX_SECURE_TLS_FINISHED:
/* Final handshake message from the server, process it (verify the server handshake hash). */
status = _nx_secure_tls_process_finished(tls_session, data_start, message_length);
/* This is the end of a flight, clear out the transmit queue. */
_nx_secure_dtls_retransmit_queue_flush(dtls_session);
break;
case NX_SECURE_TLS_HELLO_REQUEST:
/* Server has requested we restart the session. If we are in the middle of a handshake already
* (session is not active) then ignore. If we are in an active session, we can choose to
* send a ClientHello (start the handshake again) or send a no_renegotiation alert. */
/* A HelloRequest does not contain any data - it simply changes state. */
tls_session -> nx_secure_tls_client_state = NX_SECURE_TLS_CLIENT_STATE_HELLO_REQUEST;
break;
case NX_SECURE_TLS_CERTIFICATE_VERIFY:
case NX_SECURE_TLS_CLIENT_KEY_EXCHANGE:
case NX_SECURE_TLS_CLIENT_HELLO:
case NX_SECURE_TLS_INVALID_MESSAGE:
case NX_SECURE_TLS_CERTIFICATE_URL:
case NX_SECURE_TLS_CERTIFICATE_STATUS:
default:
/* The message received was not a valid TLS server handshake message, send alert and return. */
status = NX_SECURE_TLS_UNEXPECTED_MESSAGE;
break;
}
/* Check for errors in processing messages. */
if (status != NX_SECURE_TLS_SUCCESS)
{
/* Get our alert number and level from our status. */
error_number = status;
_nx_secure_tls_map_error_to_alert(error_number, &alert_number, &alert_level);
/* Release the protection before suspending on nx_packet_allocate. */
tx_mutex_put(&_nx_secure_tls_protection);
status = _nx_secure_dtls_packet_allocate(dtls_session, packet_pool, &send_packet, wait_option);
/* Get the protection after nx_packet_allocate. */
tx_mutex_get(&_nx_secure_tls_protection, TX_WAIT_FOREVER);
if (status == NX_SUCCESS)
{
_nx_secure_tls_send_alert(tls_session, send_packet, (UCHAR)alert_number, (UCHAR)alert_level);
_nx_secure_dtls_send_record(dtls_session, send_packet, NX_SECURE_TLS_ALERT, wait_option);
}
return(error_number);
}
/* Now take any actions based on state set in the message processing. */
switch (tls_session -> nx_secure_tls_client_state)
{
case NX_SECURE_TLS_CLIENT_STATE_IDLE:
/* Client isn't doing anything right now. */
break;
case NX_SECURE_TLS_CLIENT_STATE_ERROR:
case NX_SECURE_TLS_CLIENT_STATE_ALERT_SENT:
/* This means an error was encountered at some point in processing a valid message. At this point
the alert was sent, so just return a status indicating as much. */
return(NX_SECURE_TLS_HANDSHAKE_FAILURE);
break;
case NX_SECURE_TLS_CLIENT_STATE_HELLO_REQUEST:
/* Server sent a hello request, indicating it wants to restart the handshake process with a new ClientHello. */
if (tls_session -> nx_secure_tls_local_session_active)
{
/* Respond to the HelloRequest with a "no_renegotiation" alert since we don't want to restart the handshake. */
status = NX_SECURE_TLS_NO_RENEGOTIATION_ERROR;
}
/* If we are still in a handshake (session is not active) then ignore the message. */
break;
case NX_SECURE_TLS_CLIENT_STATE_HELLO_VERIFY:
/* Get ClientHello packet from header of transmit queue. */
send_packet = dtls_session -> nx_secure_dtls_transmit_sent_head;
if ((send_packet == NX_NULL) || (send_packet -> nx_packet_queue_next != ((NX_PACKET *)NX_DRIVER_TX_DONE)))
{
/* Invalid packet. */
status = NX_INVALID_PACKET;
break;
}
/* Clear the transmit queue. */
dtls_session -> nx_secure_dtls_transmit_sent_head = NX_NULL;
dtls_session -> nx_secure_dtls_transmit_sent_tail = NX_NULL;
dtls_session -> nx_secure_dtls_transmit_sent_count = 0;
/* Reset the packet. */
send_packet -> nx_packet_prepend_ptr += sizeof(NX_UDP_HEADER);
send_packet -> nx_packet_length -= sizeof(NX_UDP_HEADER);
send_packet -> nx_packet_union_next.nx_packet_tcp_queue_next = (NX_PACKET *)NX_PACKET_ALLOCATED;
_nx_secure_dtls_send_clienthello(dtls_session, send_packet);
status = _nx_secure_dtls_send_handshake_record(dtls_session, send_packet, NX_SECURE_TLS_CLIENT_HELLO, wait_option, 1);
break;
case NX_SECURE_TLS_CLIENT_STATE_SERVERHELLO:
/* We processed a serverhello above. Don't do anything right now. */
break;
case NX_SECURE_TLS_CLIENT_STATE_SERVER_CERTIFICATE:
/* Processed a server certificate above. Here, we extract the public key and do any verification
we want - the TLS implementation will verify certificate authenticity by checking the issuer
signature, but any other verification will be done by the caller via a callback. */
break;
case NX_SECURE_TLS_CLIENT_STATE_SERVER_KEY_EXCHANGE:
break;
case NX_SECURE_TLS_CLIENT_STATE_CERTIFICATE_REQUEST:
/* Set flag to send CertificateVerify once we have received ServerHelloDone. */
tls_session -> nx_secure_tls_client_certificate_requested = 1;
break;
case NX_SECURE_TLS_CLIENT_STATE_SERVERHELLO_DONE:
/* We received a ServerHelloDone, meaning we now have all the information we need to generate
our key material. First check if the server requested our client certificate. */
if (tls_session -> nx_secure_tls_client_certificate_requested)
{
/* The server has requested a client certificate. Provide that certificate to the server here. */
status = _nx_secure_dtls_allocate_handshake_packet(dtls_session, packet_pool, &send_packet, wait_option);
if (status != NX_SUCCESS)
{
break;
}
_nx_secure_tls_send_certificate(tls_session, send_packet, wait_option);
status = _nx_secure_dtls_send_handshake_record(dtls_session, send_packet, NX_SECURE_TLS_CERTIFICATE_MSG, wait_option, 1);
if (status != NX_SUCCESS)
{
break;
}
}
/* Now, generate the pre-master secret that is used to generate keys for our session. */
status = _nx_secure_tls_generate_premaster_secret(tls_session, NX_SECURE_DTLS);
if (status != NX_SUCCESS)
{
break;
}
/* We have received and processed a ServerHelloDone. Now respond to the client appropriately. */
status = _nx_secure_dtls_allocate_handshake_packet(dtls_session, packet_pool, &send_packet, wait_option);
if (status != NX_SUCCESS)
{
break;
}
/* Generate and send the ClientKeyExchange message. */
_nx_secure_tls_send_client_key_exchange(tls_session, send_packet);
status = _nx_secure_dtls_send_handshake_record(dtls_session, send_packet, NX_SECURE_TLS_CLIENT_KEY_EXCHANGE, wait_option, 1);
if (status != NX_SUCCESS)
{
break;
}
/* After sending ClientKeyExchange, we need to send a CertificateVerify message if the
server has requested a certificate. */
if (tls_session -> nx_secure_tls_client_certificate_requested)
{
/* We can now clear the flag since this is the last specific certificate message sent. */
tls_session -> nx_secure_tls_client_certificate_requested = 0;
/* Allocate packet for CertificateVerify. */
status = _nx_secure_dtls_allocate_handshake_packet(dtls_session, packet_pool, &send_packet, wait_option);
if (status != NX_SUCCESS)
{
break;
}
_nx_secure_tls_send_certificate_verify(tls_session, send_packet);
status = _nx_secure_dtls_send_handshake_record(dtls_session, send_packet, NX_SECURE_TLS_CERTIFICATE_VERIFY, wait_option, 1);
if (status != NX_SUCCESS)
{
break;
}
}
/* Generate our key material from the data collected thus far and put it all into our
socket structure. Don't call generate keys before sending the client_key_exchange message
since it needs the pre-master secret and this call clears it out (for security). */
status = _nx_secure_tls_generate_keys(tls_session);
if (status != NX_SUCCESS)
{
break;
}
/* Release the protection before suspending on nx_packet_allocate. */
tx_mutex_put(&_nx_secure_tls_protection);
/* We have received everything we need to complete the handshake. Keys have been
* generated above. Now end the handshake with a ChangeCipherSpec (indicating following
* messages are encrypted) and the encrypted Finished message. */
status = _nx_secure_dtls_packet_allocate(dtls_session, packet_pool, &send_packet, wait_option);
/* Get the protection after nx_packet_allocate. */
tx_mutex_get(&_nx_secure_tls_protection, TX_WAIT_FOREVER);
if (status != NX_SUCCESS)
{
break;
}
/* ChangeCipherSpec is NOT a handshake message, so send as a normal TLS record. */
_nx_secure_tls_send_changecipherspec(tls_session, send_packet);
status = _nx_secure_dtls_send_record(dtls_session, send_packet, NX_SECURE_TLS_CHANGE_CIPHER_SPEC, wait_option);
if (status != NX_SUCCESS)
{
/* Release packet on send error. */
nx_secure_tls_packet_release(send_packet);
break;
}
/* The local session is now active since we sent the changecipherspec message.
NOTE: Do not set this flag until after the changecipherspec message has been passed to the send record
routine - this flag causes encryption and hashing to happen on records. ChangeCipherSpec should be the last
un-encrypted/un-hashed record sent. */
/* For DTLS, reset sequence number and advance epoch right after CCS message is sent. */
NX_SECURE_MEMSET(tls_session -> nx_secure_tls_local_sequence_number, 0, sizeof(tls_session -> nx_secure_tls_local_sequence_number));
status = _nx_secure_tls_session_keys_set(tls_session, NX_SECURE_TLS_KEY_SET_LOCAL);
if (status != NX_SUCCESS)
{
break;
}
/* Advance the DTLS epoch - all messages after the ChangeCipherSpec are in a new epoch. */
dtls_session -> nx_secure_dtls_local_epoch = (USHORT)(dtls_session -> nx_secure_dtls_local_epoch + 1);
/* We can now send our finished message, which will be encrypted using the chosen ciphersuite. */
status = _nx_secure_dtls_allocate_handshake_packet(dtls_session, packet_pool, &send_packet, wait_option);
if (status != NX_SUCCESS)
{
break;
}
/* Generate and send the finished message, which completes the handshake. */
_nx_secure_tls_send_finished(tls_session, send_packet);
status = _nx_secure_dtls_send_handshake_record(dtls_session, send_packet, NX_SECURE_TLS_FINISHED, wait_option, 1);
break;
case NX_SECURE_TLS_CLIENT_STATE_HANDSHAKE_FINISHED:
/* We processed a server finished message, completing the handshake. Verify all is good and if so,
continue to the encrypted session. */
break;
default:
status = NX_SECURE_TLS_INVALID_STATE;
}
/* If we have an error at this point, we have experienced a problem in sending
handshake messages, which is some type of internal issue. Send an alert
back to the remote host indicating the error. */
if (status != NX_SUCCESS)
{
/* Get our alert number and level from our status. */
error_number = status;
_nx_secure_tls_map_error_to_alert(error_number, &alert_number, &alert_level);
/* Release the protection before suspending on nx_packet_allocate. */
tx_mutex_put(&_nx_secure_tls_protection);
status = _nx_secure_dtls_packet_allocate(dtls_session, packet_pool, &send_packet, wait_option);
/* Get the protection after nx_packet_allocate. */
tx_mutex_get(&_nx_secure_tls_protection, TX_WAIT_FOREVER);
if (status == NX_SUCCESS)
{
_nx_secure_tls_send_alert(tls_session, send_packet, (UCHAR)alert_number, (UCHAR)alert_level);
_nx_secure_dtls_send_record(dtls_session, send_packet, NX_SECURE_TLS_ALERT, wait_option);
}
return(error_number);
}
/* Advance the buffer pointer past the fragment. */
packet_buffer += (fragment_length + header_bytes);
} /* End while. */
return(NX_SUCCESS);
#else /* TLS Client disabled. */
/* We don't use the parameters since this is an error case. */
NX_PARAMETER_NOT_USED(packet_buffer);
NX_PARAMETER_NOT_USED(wait_option);
NX_PARAMETER_NOT_USED(data_length);
/* If TLS Client is disabled and we are in the client state machine, something is wrong... */
dtls_session -> nx_secure_dtls_tls_session.nx_secure_tls_server_state = NX_SECURE_TLS_SERVER_STATE_ERROR;
return(NX_SECURE_TLS_INVALID_STATE);
#endif
}
#endif /* NX_SECURE_ENABLE_DTLS */
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