move ch index

docs/docs.md

@@ -371,7 +371,9 @@ The other fields are either not sent at all, or sent in the special 16 byte LORA
 | ----- | ---- | ----- | ----------- |
 | from | [fixed32](#fixed32) |  | The sending node number. Note: Our crypto implementation uses this field as well. See docs/software/crypto.md for details. FIXME - really should be fixed32 instead, this encoding only hurts the ble link though. |
 | to | [fixed32](#fixed32) |  | The (immediatSee Priority description for more details.y should be fixed32 instead, this encoding only hurts the ble link though. |
-| channel_index | [uint32](#uint32) |  | If set, this indicates the index in the secondary_channels table that this packet was sent/received on. If unset, packet was on the primary channel. A particular node might know only a subset of channels in use on the mesh. Therefore channel_index is inherently a local concept and meaningless to send between nodes. |
+| channel | [uint32](#uint32) |  | (Usually) If set, this indicates the index in the secondary_channels table that this packet was sent/received on. If unset, packet was on the primary channel. A particular node might know only a subset of channels in use on the mesh. Therefore channel_index is inherently a local concept and meaningless to send between nodes.
+
+Very briefly, while sending and receiving deep inside the device Router code, this field instead contains the 'channel hash' instead of the index. This 'trick' is only used while the payloadVariant is an 'encrypted'. |
 | decoded | [Data](#Data) |  |  |
 | encrypted | [bytes](#bytes) |  |  |
 | id | [fixed32](#fixed32) |  | A unique ID for this packet. Always 0 for no-ack packets or non broadcast packets (and therefore take zero bytes of space). Otherwise a unique ID for this packet, useful for flooding algorithms. ID only needs to be unique on a _per sender_ basis, and it only needs to be unique for a few minutes (long enough to last for the length of any ACK or the completion of a mesh broadcast flood). Note: Our crypto implementation uses this id as well. See docs/software/crypto.md for details. FIXME - really should be fixed32 instead, this encoding only hurts the ble link though. |
@@ -871,6 +873,8 @@ details on the type of failure).
 | TIMEOUT | 3 |  |
 | NO_INTERFACE | 4 | No suitable interface could be found for delivering this packet |
 | MAX_RETRANSMIT | 5 | We reached the max retransmission count (typically for naive flood routing) |
+| NO_CHANNEL | 6 | No suitable channel was found for sending this packet (i.e. was requested channel index disabled?) |
+| TOO_LARGE | 7 | The packet was too big for sending (exceeds interface MTU after encoding) |
 
 
  

mesh.proto

@@ -152,9 +152,15 @@ message Routing {
     NO_INTERFACE = 4;
 
     /*
-      * We reached the max retransmission count (typically for naive flood routing)
-      */
+    * We reached the max retransmission count (typically for naive flood routing)
+    */
     MAX_RETRANSMIT = 5;
+
+    /* No suitable channel was found for sending this packet (i.e. was requested channel index disabled?) */
+    NO_CHANNEL = 6;
+    
+    /* The packet was too big for sending (exceeds interface MTU after encoding) */
+    TOO_LARGE = 7;
   }
 
   oneof variant {
@@ -291,12 +297,16 @@ message MeshPacket {
   fixed32 to = 2;
 
   /*
-   * If set, this indicates the index in the secondary_channels table that this packet 
+   * (Usually) If set, this indicates the index in the secondary_channels table that this packet 
    * was sent/received on.  If unset, packet was on the primary channel.
    * A particular node might know only a subset of channels in use on the mesh.  Therefore channel_index
    * is inherently a local concept and meaningless to send between nodes.
+   *
+   * Very briefly, while sending and receiving deep inside the device Router code, this field instead
+   * contains the 'channel hash' instead of the index.  This 'trick' is only used while the payloadVariant is
+   * an 'encrypted'.
    */
-  uint32 channel_index = 3;
+  uint32 channel = 3;
   
   /*
    * Internally to the mesh radios we will route SubPackets encrypted per