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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"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _nx_secure_dtls_session_start PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function starts a DTLS session given a UDP socket. */
/* */
/* INPUT */
/* */
/* dtls_session DTLS control block */
/* udp_socket UDP socket pointer */
/* is_client Is client or server */
/* wait_option Suspension option */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _nx_secure_dtls_allocate_handshake_packet */
/* Allocate DTLS handshake packet*/
/* _nx_secure_dtls_retransmit Retransmit UDP packet */
/* _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_session_receive Receive DTLS data */
/* nx_secure_tls_packet_release Release packet */
/* tx_mutex_get Get protection mutex */
/* tx_mutex_put Put protection mutex */
/* */
/* CALLED BY */
/* */
/* Application Code */
/* _nx_secure_dtls_client_session_start Client session start */
/* _nx_secure_dtls_server_session_start Server session start */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* released packet securely, */
/* fixed renegotiation bug, */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
UINT _nx_secure_dtls_session_start(NX_SECURE_DTLS_SESSION *dtls_session, NX_UDP_SOCKET *udp_socket,
UINT is_client, UINT wait_option)
{
#ifdef NX_SECURE_ENABLE_DTLS
UINT status = NX_NOT_SUCCESSFUL;
NX_PACKET *incoming_packet;
NX_SECURE_TLS_SESSION *tls_session;
UINT minimum_wait_option;
#ifndef NX_SECURE_TLS_CLIENT_DISABLED
NX_PACKET *send_packet;
#endif
/* Get the protection. */
tx_mutex_get(&_nx_secure_tls_protection, TX_WAIT_FOREVER);
/* Get reference to internal TLS state. */
tls_session = &dtls_session -> nx_secure_dtls_tls_session;
/* Assign the packet pool from which TLS will allocate internal message packets. */
tls_session -> nx_secure_tls_packet_pool = udp_socket -> nx_udp_socket_ip_ptr -> nx_ip_default_packet_pool;
/* Make sure we are starting with a fresh session. */
tls_session -> nx_secure_tls_received_remote_credentials = NX_FALSE;
#ifndef NX_SECURE_TLS_DISABLE_SECURE_RENEGOTIATION
/* Renegotiation is not enabled in DTLS session. */
tls_session -> nx_secure_tls_renegotation_enabled = NX_FALSE;
#endif /* NX_SECURE_TLS_DISABLE_SECURE_RENEGOTIATION */
/* Assign the TCP socket to the TLS session. */
dtls_session -> nx_secure_dtls_udp_socket = udp_socket;
/* Reset the record queue. */
tls_session -> nx_secure_record_queue_header = NX_NULL;
tls_session -> nx_secure_record_decrypted_packet = NX_NULL;
/* See if this is a TCP server started with listen/accept, or a TCP client started with connect. */
if (is_client)
{
/* The TCP socket is a client, so our TLS session is a TLS Client. */
tls_session -> nx_secure_tls_socket_type = NX_SECURE_TLS_SESSION_TYPE_CLIENT;
}
else
{
/* This session is now being treated as a server - indicate that fact to the TLS stack. */
tls_session -> nx_secure_tls_socket_type = NX_SECURE_TLS_SESSION_TYPE_SERVER;
}
/* Now process the handshake depending on the TLS session type. */
#ifndef NX_SECURE_TLS_CLIENT_DISABLED
if (tls_session -> nx_secure_tls_socket_type == NX_SECURE_TLS_SESSION_TYPE_CLIENT)
{
/* Allocate a handshake packet so we can send the ClientHello. */
status = _nx_secure_dtls_allocate_handshake_packet(dtls_session, tls_session -> nx_secure_tls_packet_pool, &send_packet, wait_option);
if (status != NX_SUCCESS)
{
/* Release the protection. */
tx_mutex_put(&_nx_secure_tls_protection);
return(status);
}
/* Populate our packet with clienthello data. */
status = _nx_secure_dtls_send_clienthello(dtls_session, send_packet);
if (status == NX_SUCCESS)
{
/* Send the ClientHello to kick things off. */
status = _nx_secure_dtls_send_handshake_record(dtls_session, send_packet, NX_SECURE_TLS_CLIENT_HELLO, wait_option, 0);
/* Clear the protocol version to avoid checking the version in the HelloVerifyRequest which is always DTLS 1.0. */
tls_session->nx_secure_tls_protocol_version = 0;
}
/* If anything after the allocate fails, we need to release our packet. */
if (status != NX_SUCCESS)
{
/* Release the protection. */
tx_mutex_put(&_nx_secure_tls_protection);
nx_secure_tls_packet_release(send_packet);
return(status);
}
}
#endif
/* Now handle our incoming handshake messages. Continue processing until the handshake is complete
* or an error/timeout occurs. */
for (;;)
{
#ifndef NX_SECURE_TLS_CLIENT_DISABLED
if ((tls_session -> nx_secure_tls_socket_type == NX_SECURE_TLS_SESSION_TYPE_CLIENT) &&
(tls_session -> nx_secure_tls_client_state == NX_SECURE_TLS_CLIENT_STATE_HANDSHAKE_FINISHED))
{
break;
}
#endif
#ifndef NX_SECURE_TLS_SERVER_DISABLED
if ((tls_session -> nx_secure_tls_socket_type == NX_SECURE_TLS_SESSION_TYPE_SERVER) &&
(tls_session -> nx_secure_tls_server_state == NX_SECURE_TLS_SERVER_STATE_HANDSHAKE_FINISHED))
{
break;
}
#endif
if ((dtls_session -> nx_secure_dtls_handshake_timeout > wait_option) ||
(dtls_session -> nx_secure_dtls_handshake_timeout == 0) ||
(dtls_session -> nx_secure_dtls_transmit_sent_head == NX_NULL))
{
minimum_wait_option = wait_option;
}
else
{
minimum_wait_option = dtls_session -> nx_secure_dtls_handshake_timeout;
}
/* Release the protection. */
tx_mutex_put(&_nx_secure_tls_protection);
status = _nx_secure_dtls_session_receive(dtls_session, &incoming_packet,
minimum_wait_option);
/* Get the protection. */
tx_mutex_get(&_nx_secure_tls_protection, TX_WAIT_FOREVER);
/* Make sure we didn't have an error during the receive. */
if (status != NX_SUCCESS)
{
/* Check error status. */
if (status != NX_NO_PACKET && status != NX_CONTINUE)
{
break;
}
if (minimum_wait_option == wait_option)
{
break;
}
if (dtls_session -> nx_secure_dtls_timeout_retries >=
NX_SECURE_DTLS_MAXIMUM_RETRANSMIT_RETRIES)
{
break;
}
/* Retransmit timeout. */
_nx_secure_dtls_retransmit(dtls_session);
/* Decrease the wait option. */
wait_option -= minimum_wait_option;
}
else
{
/* On any error, the handshake has failed so break out of our processing loop and return. */
nx_secure_tls_packet_release(incoming_packet);
}
}
/* This is the end of a flight, clear out the transmit queue. */
_nx_secure_dtls_retransmit_queue_flush(dtls_session);
/* Release the protection. */
tx_mutex_put(&_nx_secure_tls_protection);
return(status);
#else
NX_PARAMETER_NOT_USED(dtls_session);
NX_PARAMETER_NOT_USED(udp_socket);
NX_PARAMETER_NOT_USED(is_client);
NX_PARAMETER_NOT_USED(wait_option);
return(NX_NOT_SUPPORTED);
#endif /* NX_SECURE_ENABLE_DTLS */
}
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