* docs changes for PAYLOAD_TYPE_GRP_DATA

docs/cli_commands.md

@@ -557,7 +557,7 @@ This document provides an overview of CLI commands that can be sent to MeshCore
 - `set agc.reset.interval <value>`
 
 **Parameters:**
-- `value`: Interval in seconds rounded down to a multiple of 4 (17 becomes 16)
+- `value`: Interval in seconds rounded down to a multiple of 4 (17 becomes 16). 0 to disable.
 
 **Default:** `0.0`
 

docs/number_allocations.md

@@ -0,0 +1,16 @@
+# Number Allocations
+
+This document lists unique numbers/identifiers used in various MeshCore protcol payloads.
+
+# Group Data Types
+
+The `PAYLOAD_TYPE_GRP_DATA` payloads have a 16-bit data-type field, which identifies which application the packet is for.
+
+To make sure multiple applications can function without interfering with each other, the table below is for reserving various ranges of data-type values. Just modify this table, adding a row, then submit a PR to have it authorised/merged.
+
+The 16-bit types are allocated in blocks of 16, ie. the lower 4-bits is the range.
+
+| Data-Type range | App name                 | Contact                                              |
+|-----------------|--------------------------|------------------------------------------------------|
+| 000x            | -reserved-               |  |
+| FFFx            | -reserved-               |  |

docs/payloads.md

@@ -226,7 +226,7 @@ txt_type
 | reply path     | (variable)      | reply path                                                       |
 
 
-# Group text message / datagram
+# Group text message
 
 | Field        | Size (bytes)    | Description                                |
 |--------------|-----------------|--------------------------------------------|
@@ -236,6 +236,22 @@ txt_type
 
 The plaintext contained in the ciphertext matches the format described in [plain text message](#plain-text-message). Specifically, it consists of a four byte timestamp, a flags byte, and the message. The flags byte will generally be `0x00` because it is a "plain text message". The message will be of the form `<sender name>: <message body>` (eg., `user123: I'm on my way`).
 
+# Group datagram
+
+| Field        | Size (bytes)    | Description                                |
+|--------------|-----------------|--------------------------------------------|
+| channel hash | 1               | first byte of SHA256 of channel's shared key  |
+| cipher MAC   | 2               | MAC for encrypted data in next field       |
+| ciphertext   | rest of payload | encrypted data, see below for details   |
+
+The data contained in the ciphertext uses the format below:
+
+| Field        | Size (bytes)    | Description                                |
+|--------------|-----------------|--------------------------------------------|
+| data type    | 2               | Identifier for type of data. (See number_allocations.md)  |
+| data len     | 1               | byte length of data         |
+| data         | rest of payload | (depends on data type)     |
+
 
 # Control data