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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_packet_allocate PORTABLE C */
/* 6.1 */
/* AUTHOR */
/* */
/* Timothy Stapko, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function allocates a packet for DTLS. */
/* */
/* INPUT */
/* */
/* dtls_session DTLS control block */
/* pool_ptr Pool to allocate packet from */
/* packet_ptr Pointer to place allocated */
/* packet pointer */
/* wait_option Suspension option */
/* */
/* OUTPUT */
/* */
/* status Completion status */
/* */
/* CALLS */
/* */
/* _nx_secure_tls_session_iv_size_get Get IV size for this session. */
/* nx_packet_allocate NetX Packet allocation call. */
/* */
/* CALLED BY */
/* */
/* Application */
/* _nx_secure_dtls_allocate_handshake_packet */
/* Allocate DTLS handshake packet*/
/* _nx_secure_dtls_client_handshake DTLS client state machine */
/* _nx_secure_dtls_server_handshake DTLS server state machine */
/* _nx_secure_dtls_session_end Actual DTLS session end call. */
/* _nx_secure_dtls_session_receive Receive DTLS data */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 05-19-2020 Timothy Stapko Initial Version 6.0 */
/* 09-30-2020 Timothy Stapko Modified comment(s), */
/* resulting in version 6.1 */
/* */
/**************************************************************************/
UINT _nx_secure_dtls_packet_allocate(NX_SECURE_DTLS_SESSION *dtls_session, NX_PACKET_POOL *pool_ptr,
NX_PACKET **packet_ptr, ULONG wait_option)
{
#ifdef NX_SECURE_ENABLE_DTLS
UINT status;
ULONG packet_type;
USHORT iv_size;
NX_SECURE_TLS_SESSION *tls_session;
if (dtls_session -> nx_secure_dtls_remote_ip_address.nxd_ip_version == NX_IP_VERSION_V4)
{
packet_type = NX_IPv4_UDP_PACKET;
}
else
{
packet_type = NX_IPv6_UDP_PACKET;
}
status = nx_packet_allocate(pool_ptr, packet_ptr, packet_type, wait_option);
if (status != NX_SUCCESS)
{
return(NX_SECURE_TLS_ALLOCATE_PACKET_FAILED);
}
if (((ULONG)((*packet_ptr) -> nx_packet_data_end) - (ULONG)((*packet_ptr) -> nx_packet_prepend_ptr)) <
(NX_SECURE_DTLS_RECORD_HEADER_SIZE + 2u)) /* At least 2 bytes for Alert message. */
{
/* Packet buffer is too small. */
nx_packet_release(*packet_ptr);
return(NX_SECURE_TLS_PACKET_BUFFER_TOO_SMALL);
}
/* Advance the packet prepend pointer past the record header. */
(*packet_ptr) -> nx_packet_prepend_ptr += NX_SECURE_DTLS_RECORD_HEADER_SIZE;
/* Get a pointer to TLS state. */
tls_session = &dtls_session -> nx_secure_dtls_tls_session;
/* If TLS session is active, allocate space for the IV that precedes the data in
certain ciphersuites. */
if (tls_session -> nx_secure_tls_local_session_active)
{
/* Get the size of the IV used by the session cipher. */
status = _nx_secure_tls_session_iv_size_get(tls_session, &iv_size);
if (status != NX_SUCCESS)
{
return(status);
}
if ((iv_size + 2u) > ((ULONG)((*packet_ptr) -> nx_packet_data_end) - (ULONG)((*packet_ptr) -> nx_packet_prepend_ptr)))
{
/* Packet buffer is too small to hold IV. */
nx_packet_release(*packet_ptr);
*packet_ptr = NX_NULL;
return(NX_SECURE_TLS_PACKET_BUFFER_TOO_SMALL);
}
/* Don't do anything if no IV is required. */
if (iv_size > 0)
{
/* Pre-allocate space for the session cipher IV and clear it out. */
NX_SECURE_MEMSET((*packet_ptr) -> nx_packet_prepend_ptr, 0, iv_size);
(*packet_ptr) -> nx_packet_prepend_ptr += iv_size;
}
}
/* Make sure our append and prepend pointers are pointing to the same thing - when
the packet is allocated it is "empty" from a user perspective. */
(*packet_ptr) -> nx_packet_append_ptr = (*packet_ptr) -> nx_packet_prepend_ptr;
(*packet_ptr) -> nx_packet_length = 0;
return(NX_SECURE_TLS_SUCCESS);
#else
NX_PARAMETER_NOT_USED(dtls_session);
NX_PARAMETER_NOT_USED(pool_ptr);
NX_PARAMETER_NOT_USED(packet_ptr);
NX_PARAMETER_NOT_USED(wait_option);
return(NX_NOT_SUPPORTED);
#endif /* NX_SECURE_ENABLE_DTLS */
}