1 /**************************************************************************/
2 /* */
3 /* Copyright (c) Microsoft Corporation. All rights reserved. */
4 /* */
5 /* This software is licensed under the Microsoft Software License */
6 /* Terms for Microsoft Azure RTOS. Full text of the license can be */
7 /* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
8 /* and in the root directory of this software. */
9 /* */
10 /**************************************************************************/
11
12
13 /**************************************************************************/
14 /**************************************************************************/
15 /** */
16 /** NetX Secure Component */
17 /** */
18 /** Datagram Transport Layer Security (DTLS) */
19 /** */
20 /**************************************************************************/
21 /**************************************************************************/
22
23 #define NX_SECURE_SOURCE_CODE
24
25 #include "nx_secure_dtls.h"
26
27 #ifdef NX_SECURE_ENABLE_DTLS
28 /**************************************************************************/
29 /* */
30 /* FUNCTION RELEASE */
31 /* */
32 /* _nx_secure_dtls_process_handshake_header PORTABLE C */
33 /* 6.1.3 */
34 /* AUTHOR */
35 /* */
36 /* Timothy Stapko, Microsoft Corporation */
37 /* */
38 /* DESCRIPTION */
39 /* */
40 /* This function processes a DTLS Handshake record header, which is */
41 /* at the beginning of each DTLS Handshake message, encapsulated */
42 /* within the DTLS record itself. */
43 /* */
44 /* INPUT */
45 /* */
46 /* packet_buffer Pointer to incoming packet */
47 /* message_type Return message type value */
48 /* header_size Input size of packet buffer */
49 /* Return size of header */
50 /* message_length Return length of message */
51 /* message_seq Return sequence of message */
52 /* fragment_offset Return offset of fragment */
53 /* fragment_length Return length of fragment */
54 /* */
55 /* OUTPUT */
56 /* */
57 /* status Completion status */
58 /* */
59 /* CALLS */
60 /* */
61 /* None */
62 /* */
63 /* CALLED BY */
64 /* */
65 /* _nx_secure_dtls_client_handshake DTLS client state machine */
66 /* _nx_secure_dtls_server_handshake DTLS server state machine */
67 /* */
68 /* RELEASE HISTORY */
69 /* */
70 /* DATE NAME DESCRIPTION */
71 /* */
72 /* 05-19-2020 Timothy Stapko Initial Version 6.0 */
73 /* 09-30-2020 Timothy Stapko Modified comment(s), */
74 /* resulting in version 6.1 */
75 /* 12-31-2020 Timothy Stapko Modified comment(s), */
76 /* improved buffer length */
77 /* verification, */
78 /* resulting in version 6.1.3 */
79 /* */
80 /**************************************************************************/
_nx_secure_dtls_process_handshake_header(UCHAR * packet_buffer,USHORT * message_type,UINT * header_size,UINT * message_length,UINT * message_seq,UINT * fragment_offset,UINT * fragment_length)81 UINT _nx_secure_dtls_process_handshake_header(UCHAR *packet_buffer, USHORT *message_type,
82 UINT *header_size, UINT *message_length,
83 UINT *message_seq, UINT *fragment_offset,
84 UINT *fragment_length)
85 {
86
87 /* Check buffer length. */
88 if (*header_size < NX_SECURE_DTLS_HANDSHAKE_HEADER_SIZE)
89 {
90 return(NX_SECURE_TLS_INCORRECT_MESSAGE_LENGTH);
91 }
92
93 /* The message being passed in to this function should already be stripped of the TLS header
94 so the first byte in the packet/record is our handshake message type. */
95 *message_type = packet_buffer[0];
96 packet_buffer++;
97
98 /* Get the length of the TLS data. */
99 *message_length = (UINT)((packet_buffer[0] << 16) + (packet_buffer[1] << 8) + packet_buffer[2]);
100 packet_buffer += 3;
101
102 /* Extract message sequence number. */
103 *message_seq = (UINT)((packet_buffer[0] << 8) + packet_buffer[1]);
104 packet_buffer += 2;
105
106 /* Extract fragment offset. */
107 *fragment_offset = (UINT)((packet_buffer[0] << 16) + (packet_buffer[1] << 8) + packet_buffer[2]);
108 packet_buffer += 3;
109
110 /* Extract fragment length. */
111 *fragment_length = (UINT)((packet_buffer[0] << 16) + (packet_buffer[1] << 8) + packet_buffer[2]);
112
113 /* We have extracted the DTLS header. */
114 *header_size = NX_SECURE_DTLS_HANDSHAKE_HEADER_SIZE;
115
116 return(NX_SECURE_TLS_SUCCESS);
117 }
118 #endif /* NX_SECURE_ENABLE_DTLS */
119
120
