about summary refs log tree commit diff
path: root/protocol.md
blob: 7a9e2341284131c6e5fe3d14209211d1bdfba06c (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
Broadlink RM2 network protocol
==============================

Encryption
----------

Packets include AES-based encryption in CBC mode. The initial key is 0x09, 0x76, 0x28, 0x34, 0x3f, 0xe9, 0x9e, 0x23, 0x76, 0x5c, 0x15, 0x13, 0xac, 0xcf, 0x8b, 0x02. The IV is 0x56, 0x2e, 0x17, 0x99, 0x6d, 0x09, 0x3d, 0x28, 0xdd, 0xb3, 0xba, 0x69, 0x5a, 0x2e, 0x6f, 0x58.

Checksum
--------

Construct the packet and set checksum bytes to zero. Add each byte to the starting value of 0xbeaf, wrapping after 0xffff.

Network discovery
-----------------

To discover Broadlink devices on the local network, send a 48 byte packet with the following contents:

| Offset  | Contents |
|---------|----------|
|0x00-0x07|00|
|0x08-0x0b|Current offset from GMT as a little-endian 32 bit integer|
|0x0c-0x0d|Current year as a little-endian 16 bit integer|
|0x0e|Current number of minutes past the hour|
|0x0f|Current number of hours past midnight|
|0x10|Current number of years past the century|
|0x11|Current day of the week (Monday = 0, Tuesday = 1, etc)|
|0x12|Current day in month|
|0x13|Current month|
|0x19-0x1b|Local IP address|
|0x1c-0x1d|Source port as a little-endian 16 bit integer|
|0x1e-0x1f|00|
|0x20-0x21|Checksum as a little-endian 16 bit integer|
|0x22-0x25|00|
|0x26|06|
|0x27-0x2f|00|

Send this packet as a UDP broadcast to 255.255.255.255 on port 80.

Response (any unicast response):
| Offset  | Contents |
|---------|----------|
|0x34-0x35|Device type as a little-endian 16 bit integer (see device type mapping)|
|0x3a-0x40|MAC address of the target device|

Device type mapping:
| Device type in response packet | Device type | Treat as |
|---------|----------|----------|
|0|SP1|SP1|
|0x2711|SP2|SP2|
|0x2719 or 0x7919 or 0x271a or 0x791a|Honeywell SP2|SP2|
|0x2720|SPMini|SP2|
|0x753e|SP3|SP2|
|0x2728|SPMini2|SP2
|0x2733 or 0x273e|OEM branded SPMini|SP2|
|>= 0x7530 and <= 0x7918|OEM branded SPMini2|SP2|
|0x2736|SPMiniPlus|SP2|
|0x2712|RM2|RM|
|0x2737|RM Mini / RM3 Mini Blackbean|RM|
|0x273d|RM Pro Phicomm|RM|
|0x2783|RM2 Home Plus|RM|
|0x277c|RM2 Home Plus GDT|RM|
|0x272a|RM2 Pro Plus|RM|
|0x2787|RM2 Pro Plus2|RM|
|0x278b|RM2 Pro Plus BL|RM|
|0x278f|RM Mini Shate|RM|
|0x2714|A1|A1|
|0x4EB5|MP1|MP1|


Command packet format
---------------------

The command packet header is 56 bytes long with the following format:

|Offset|Contents|
|------|--------|
|0x00|0x5a|
|0x01|0xa5|
|0x02|0xaa|
|0x03|0x55|
|0x04|0x5a|
|0x05|0xa5|
|0x06|0xaa|
|0x07|0x55|
|0x08-0x1f|00|
|0x20-0x21|Checksum of full packet as a little-endian 16 bit integer|
|0x22-0x23|00|
|0x24|0x2a|
|0x25|0x27|
|0x26-0x27|Command code as a little-endian 16 bit integer|
|0x28-0x29|Packet count as a little-endian 16 bit integer|
|0x2a-0x2f|Local MAC address|
|0x30-0x33|Local device ID (obtained during authentication, 00 before authentication)|
|0x34-0x35|Checksum of packet header as a little-endian 16 bit integer
|0x36-0x37|00|

The payload is appended immediately after this. The checksum at 0x34 is calculated *before* the payload is appended, and covers only the header. The checksum at 0x20 is calculated *after* the payload is appended, and covers the entire packet (including the checksum at 0x34). Therefore:

1. Generate packet header with checksum values set to 0
2. Set the checksum initialisation value to 0xbeaf and calculate the checksum of the packet header. Set 0x34-0x35 to this value.
3. Append the payload
4. Set the checksum initialisation value to 0xbeaf and calculate the checksum of the entire packet. Set 0x20-0x21 to this value.

Authorisation
-------------

You must obtain an authorisation key from the device before you can communicate. To do so, generate an 80 byte packet with the following contents:

|Offset|Contents|
|------|--------|
|0x00-0x03|00|
|0x04-0x12|A 15-digit value that represents this device. Broadlink's implementation uses the IMEI.|
|0x13|01|
|0x14-0x2c|00|
|0x2d|0x01|
|0x30-0x7f|NULL-terminated ASCII string containing the device name|

Send this payload with a command value of 0x0065. The response packet will contain an encrypted payload from byte 0x38 onwards. Decrypt this using the default key and IV. The format of the decrypted payload is:

|Offset|Contents|
|------|--------|
|0x00-0x03|Device ID|
|0x04-0x13|Device encryption key|

All further command packets must use this encryption key and device ID.

Entering learning mode
----------------------

Send the following 16 byte payload with a command value of 0x006a:

|Offset|Contents|
|------|--------|
|0x00|0x03|
|0x01-0x0f|0x00|

Reading back data from learning mode
------------------------------------

Send the following 16 byte payload with a command value of 0x006a:

|Offset|Contents|
|------|--------|
|0x00|0x04|
|0x01-0x0f|0x00|

Byte 0x22 of the response contains a little-endian 16 bit error code. If this is 0, a code has been obtained. Bytes 0x38 and onward of the response are encrypted. Decrypt them. Bytes 0x04 and onward of the decrypted payload contain the captured data.

Sending data
------------

Send the following payload with a command byte of 0x006a

|Offset|Contents|
|------|--------|
|0x00|0x02|
|0x01-0x03|0x00|
|0x04-end|data|


Todo
----

* Support for other devices using the Broadlink protocol (various smart home devices)
* Figure out what the format of the data packets actually is.