meshtastic-protobuf/docs/docs.md

Protocol Documentation

Table of Contents

• mesh.proto

  • ChannelSettings

  • Data

  • DebugString

  • DeviceState

  • FromRadio

  • MeshPacket

  • MyNodeInfo

  • NodeInfo

  • Position

  • RadioConfig

  • RadioConfig.UserPreferences

  • RouteDiscovery

  • SubPacket

  • ToRadio

  • User

  • ChannelSettings.ModemConfig

  • Constants

  • GpsOperation

  • LocationSharing

  • RegionCode

  • RouteError

• portnums.proto

  • PortNum

• Scalar Value Types

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mesh.proto

Meshtastic protobufs

For more information on protobufs (and tools to use them with the language of your choice) see https://developers.google.com/protocol-buffers/docs/proto3

We are not placing any of these defs inside a package, because if you do the resulting nanopb version is super verbose package mesh.

Protobuf build instructions:

To build java classes for reading writing: protoc -I=. --java_out /tmp mesh.proto

To generate Nanopb c code: /home/kevinh/packages/nanopb-0.4.0-linux-x86/generator-bin/protoc --nanopb_out=/tmp -I=app/src/main/proto mesh.proto

Nanopb binaries available here: https://jpa.kapsi.fi/nanopb/download/ use nanopb 0.4.0

ChannelSettings

Full settings (center freq, spread factor, pre-shared secret key etc...) needed to configure a radio for speaking on a particlar channel This information can be encoded as a QRcode/url so that other users can configure their radio to join the same channel. A note aboute how channel names are shown to users: channelname-Xy poundsymbol is a prefix used to indicate this is a channel name (idea from @professr). Where X is a letter from A-Z (base 26) representing a hash of the PSK for this channel - so that if the user changes anything about the channel (which does force a new PSK) this letter will also change. Thus preventing user confusion if two friends try to type in a channel name of "BobsChan" and then can't talk because their PSKs will be different. The PSK is hashed into this letter by "0x41 + [xor all bytes of the psk ] modulo 26" This also allows the option of someday if people have the PSK off (zero), the users COULD type in a channel name and be able to talk. Y is a lower case letter from a-z that represents the channel 'speed' settings (for some future definition of speed)

Field	Type	Label	Description
tx_power	int32		If zero then, use default max legal continuous power (ie. something that won't burn out the radio hardware) In most cases you should use zero here.
modem_config	ChannelSettings.ModemConfig		Note: This is the 'old' mechanism for specifying channel parameters. / Either modem_config or bandwidth/spreading/coding will be specified - NOT / BOTH. As a heuristic: If bandwidth is specified, do not use modem_config. / Because protobufs take ZERO space when the value is zero this works out / nicely. / This value is replaced by bandwidth/spread_factor/coding_rate. If you'd / like to experiment with other options add them to MeshRadio.cpp in the / device code.
bandwidth	uint32		Bandwidth in MHz Certain bandwidth numbers are 'special' and will be converted to the appropriate floating point value: 31 -> 31.25MHz
spread_factor	uint32		A number from 7 to 12. Indicates number of chirps per symbol as 1<<spread_factor.
coding_rate	uint32		The denominator of the coding rate. ie for 4/8, the value is 8. 5/8 the value is 5.
channel_num	uint32		A channel number between 1 and 13 (or whatever the max is in the current region). If ZERO then the rule is "use the old channel name hash based algoritm to derive the channel number") If using the hash algorithm the channel number will be: hash(channel_name) % NUM_CHANNELS (Where num channels depends on the regulatory region). NUM_CHANNELS_US is 13, for other values see MeshRadio.h in the device code. hash a string into an integer - djb2 by Dan Bernstein. - http://www.cse.yorku.ca/~oz/hash.html unsigned long hash(char *str) { unsigned long hash = 5381; int c; while ((c = *str++) != 0) hash = ((hash << 5) + hash) + (unsigned char) c; return hash; }
psk	bytes		A simple preshared key for now for crypto. Must be either 0 bytes (no / crypto), 16 bytes (AES128), or 32 bytes (AES256)
name	string		A SHORT name that will be packed into the URL. Less than 12 bytes. / Something for end users to call the channel

Data

a data message to forward to an external app (or possibly also be consumed internally in the case of CLEAR_TEXT and CLEAR_READACK)

Field	Type	Label	Description
portnum	PortNum		formerly named typ and of type Type
payload	bytes		required

DebugString

Debug output from the device

Field	Type	Label	Description
message	string

DeviceState

This message is never sent over the wire, but it is used for serializing DB state to flash in the device code FIXME, since we write this each time we enter deep sleep (and have infinite flash) it would be better to use some sort of append only data structure for the receive queue and use the preferences store for the other stuff

Field	Type	Label	Description
radio	RadioConfig
my_node	MyNodeInfo		Read only settings/info about this node
owner	User		My owner info
node_db	NodeInfo	repeated
receive_queue	MeshPacket	repeated	Received packets saved for delivery to the phone
version	uint32		A version integer used to invalidate old save files when we make incompatible changes This integer is set at build time and is private to NodeDB.cpp in the device code.
rx_text_message	MeshPacket		We keep the last received text message (only) stored in the device flash, so we can show it on the screen. Might be null
no_save	bool		Used only during development. Indicates developer is testing and changes should never be saved to flash.
did_gps_reset	bool		Some GPSes seem to have bogus settings from the factory, so we always do one factory reset

FromRadio

packets from the radio to the phone will appear on the fromRadio characteristic. It will support READ and NOTIFY. When a new packet arrives the device will BLE notify? it will sit in that descriptor until consumed by the phone, at which point the next item in the FIFO will be populated.

Field	Type	Label	Description
num	uint32		The packet num, used to allow the phone to request missing read packets from the FIFO, see our bluetooth docs
packet	MeshPacket
my_info	MyNodeInfo		Tells the phone what our node number is, can be -1 if we've not yet joined a mesh.
node_info	NodeInfo		One packet is sent for each node in the on radio DB starts over with the first node in our DB
radio	RadioConfig		In rev1 this was the radio BLE characteristic
debug_string	DebugString		set to send debug console output over our protobuf stream
config_complete_id	uint32		sent as true once the device has finished sending all of the responses to want_config recipient should check if this ID matches our original request nonce, if not, it means your config responses haven't started yet
rebooted	bool		Sent to tell clients the radio has just rebooted. Set to true if present. Not used on all transports, currently just used for the serial console.

MeshPacket

A full packet sent/received over the mesh Note: For simplicity reasons (and that we want to keep over the radio packets very small, we now assume that there is only one SubPacket in each MeshPacket).

Field	Type	Label	Description
from	uint32		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	uint32		The (immediate) destination for this packet. If we are using routing, the final destination will be in payload.dest FIXME - really should be fixed32 instead, this encoding only hurts the ble link though.
decoded	SubPacket
encrypted	bytes
id	uint32		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.
rx_time	fixed32		The time this message was received by the esp32 (secs since 1970). Note: / this field is never sent on the radio link itself (to save space) Times / are typically not sent over the mesh, but they will be added to any Packet / (chain of SubPacket) sent to the phone (so the phone can know exact time / of reception)
rx_snr	float		Never* sent over the radio links. Set during reception to indicate the / SNR / of this packet. Used to collect statistics on current link waulity.
hop_limit	uint32		If unset treated as zero (no fowarding, send to adjacent nodes only) if 1, allow hopping through one node, etc... For our usecase real world topologies probably have a max of about 3. This field is normally placed into a few of bits in the header.
want_ack	bool		This packet is being sent as a reliable message, we would prefer it to arrive at the destination. We would like to receive a ack packet in response. Broadcasts messages treat this flag specially: Since acks for broadcasts would rapidly flood the channel, the normal ack behavior is suppressed. Instead, the original sender listens to see if at least one node is rebroadcasting this packet (because naive flooding algoritm). If it hears that the odds (given typical LoRa topologies) the odds are very high that every node should eventually receive the message. So FloodingRouter.cpp generates an implicit ack which is delivered to the original sender. If after some time we don't hear anyone rebroadcast our packet, we will timeout and retransmit, using the regular resend logic. Note: This flag is normally sent in a flag bit in the header when sent over the wire

MyNodeInfo

Unique local debugging info for this node

Note: we don't include position or the user info, because that will come in the

Sent to the phone in response to WantNodes.

Field	Type	Label	Description
my_node_num	uint32		Tells the phone what our node number is, default starting value is lowbyte / of macaddr, but it will be fixed if that is already in use
has_gps	bool		Note: this bool no longer means "we have our own GPS". Because gps_operation is more advanced, but we'd like old phone apps to keep working. So for legacy reasons we set this flag as follows: if false it would be great if the phone can help provide gps coordinates. If true we don't need location assistance from the phone.
num_channels	int32		# of legal channels (set at build time in the device flash image)
region	string		The region code for my radio (US, CN, etc...) Note: This string is deprecated. The 1.0 builds populate it based on the flashed firmware name. But for newer builds this string will be unpopulated (missing/null). For those builds you should instead look at the new read/write region enum in UserSettings The format of this string was 1.0-US or 1.0-CN etc.. Or empty string if unset.
hw_model	string		TBEAM, HELTEC, etc...
firmware_version	string		0.0.5 etc...
error_code	uint32		An error message we'd like to report back to the mothership through / analytics. It indicates a serious bug occurred on the device, the device / coped with it, but we still want to tell the devs about the bug. This / field will be cleared after the phone reads MyNodeInfo (i.e. it will only / be reported once) a numeric error code to go with error message, zero / means no error
error_address	uint32		A numeric error address (nonzero if available)
error_count	uint32		The total number of errors this node has ever encountered (well - since / the last time we discarded preferences)
packet_id_bits	uint32		How many bits are used for the packetid. If zero it is assumed we use eight bit packetids Old device loads (older that 0.6.5 do not populate this field, but all newer loads do).
current_packet_id	uint32		The current ID this node is using for sending new packets (exposed so that the phone can self assign packet IDs if it wishes by picking packet IDs from the opposite side of the pacekt ID space). Old device loads (older that 0.6.5 do not populate this field, but all newer loads do). FIXME: that we need to expose this is a bit of a mistake. Really the phones should be modeled/treated as 1st class nodes like any other, and the radio connected to the phone just routes like any other. This would allow all sorts of clean/clever routing topologies in the future.
node_num_bits	uint32		How many bits are used for the nodenum. If zero it is assumed we use eight bit nodenums New device loads will user 32 bit nodenum. Old device loads (older that 0.6.5 do not populate this field, but all newer loads do).
message_timeout_msec	uint32		How long before we consider a message abandoned and we can clear our caches of any messages in flight Normally quite large to handle the worst case message delivery time, 5 minutes. Formerly called FLOOD_EXPIRE_TIME in the device code
min_app_version	uint32		The minimum app version that can talk to this device. Android apps should compare this to their build number and if too low tell the user they must update their app

NodeInfo

Full information about a node on the mesh

Field	Type	Label	Description
num	uint32		the node number
user	User
position	Position		This position data will also contain a time last seen
snr	float		Returns the Signal-to-noise ratio (SNR) of the last received message, as / measured by the receiver. return SNR of the last received message in dB
next_hop	uint32		Our current preferred node node for routing - might be the same as num if / we are adjacent Or zero if we don't yet know a route to this node.

Position

a gps position

Field	Type	Label	Description
latitude_i	sint32		The new preferred location encoding, divide by 1e-7 to get degrees in floating point
longitude_i	sint32
altitude	int32		In meters above MSL
battery_level	int32		1-100 (0 means not provided)
time	fixed32		This is usually not sent over the mesh (to save space), but it is sent / from the phone so that the local device can set its RTC If it is sent over / the mesh (because there are devices on the mesh without GPS), it will only / be sent by devices which has a hardware GPS clock. / seconds since 1970

RadioConfig

The entire set of user settable/readable settings for our radio device. Includes both the current channel settings and any preferences the user has set for behavior of their node

Field	Type	Label	Description
preferences	RadioConfig.UserPreferences
channel_settings	ChannelSettings

RadioConfig.UserPreferences

see sw-design.md for more information on these preferences

Field	Type	Label	Description
position_broadcast_secs	uint32		We should send our position this often (but only if it has changed significantly)
send_owner_interval	uint32		Send our owner info at least this often (also we always send once at boot - to rejoin the mesh)
num_missed_to_fail	uint32		If we miss this many owner messages from a node, we declare the node / offline (defaults to 3 - to allow for some lost packets)
wait_bluetooth_secs	uint32		0 for default of 1 minute
screen_on_secs	uint32		0 for default of one minute
phone_timeout_secs	uint32		0 for default of 15 minutes
phone_sds_timeout_sec	uint32		0 for default of two hours, MAXUINT for disabled
mesh_sds_timeout_secs	uint32		0 for default of two hours, MAXUINT for disabled
sds_secs	uint32		0 for default of one year
ls_secs	uint32		0 for default of 3600
min_wake_secs	uint32		0 for default of 10 seconds
wifi_ssid	string		If set, this node will try to join the specified wifi network and acquire an address via DHCP
wifi_password	string		If set, will be use to authenticate to the named wifi
wifi_ap_mode	bool		If set, the node will operate as an AP (and DHCP server), otherwise it will be a station
region	RegionCode		The region code for my radio (US, CN, EU433, etc...)
is_router	bool		Are we operating as a router. Changes behavior in the following ways: FIXME
is_low_power	bool		If set, we are powered from a low-current source (i.e. solar), so even if it looks like we have power flowing in we should try to minimize power consumption as much as possible. Often combined with is_router.
factory_reset	bool		This setting is never saved to disk, but if set, all device settings will be returned to factory defaults. (Region, serial number etc... will be preserved)
location_share	LocationSharing
gps_operation	GpsOperation
gps_update_interval	uint32		How often should we try to get GPS position (in seconds) when we are in GpsOpMobile mode? or zero for the default of once every 30 seconds or a very large value (maxint) to update only once at boot.
gps_attempt_time	uint32		How long should we try to get our position during each gps_update_interval attempt? (in seconds) Or if zero, use the default of 30 seconds. If we don't get a new gps fix in that time, the gps will be put into sleep until the next gps_update_rate window.
ignore_incoming	uint32	repeated	For testing it is useful sometimes to force a node to never listen to particular other nodes (simulating radio out of range). All nodenums listed in ignore_incoming will have packets they send droped on receive (by router.cpp)

RouteDiscovery

A message used in our Dynamic Source Routing protocol (RFC 4728 based)

Field	Type	Label	Description
route	int32	repeated	The list of nodes this packet has visited so far

SubPacket

The payload portion fo a packet, this is the actual bytes that are sent inside a radio packet (because from/to are broken out by the comms library)

Field	Type	Label	Description
position	Position		Prior to 1.20 positions were communicated as a special payload type, now they are GPS_POSITION_APP Data
data	Data
user	User		Prior to 1.20 positions were communicated as a special payload type, now they are MESH_USERINFO_APP
route_request	RouteDiscovery		A route request going from the requester
route_reply	RouteDiscovery		A route reply
route_error	RouteError		A failure in a routed message
want_response	bool		Not normally used, but for testing a sender can request that recipient / responds in kind (i.e. if it received a position, it should unicast back / its position). Note: that if you set this on a broadcast you will receive many replies. FIXME - unify (i.e. remove) this with the new reliable messaging at the MeshPacket level
success_id	uint32		This packet is a requested acknoledgement indicating that we have received the specified message ID. This packet type can be used both for immediate (0 hops) messages or can be routed through multiple hops if dest is set. Note: As an optimization, recipients can also populate a field in payload if they think the recipient would appreciate that extra state.
fail_id	uint32		This is a nak, we failed to deliver this message.
dest	uint32		The address of the destination node. This field is is filled in by the mesh radio device software, applicaiton layer software should never need it. RouteDiscovery messages must populate this. Other message types might need to if they are doing multihop routing.
source	uint32		The address of the original sender for this message. This field should only be populated for reliable multihop packets (to keep packets small).
original_id	uint32		Only used in route_error messages. Indicates the original message ID that this message is reporting failure on.

ToRadio

packets/commands to the radio will be written (reliably) to the toRadio characteristic. Once the write completes the phone can assume it is handled.

Field	Type	Label	Description
packet	MeshPacket		send this packet on the mesh
want_config_id	uint32		phone wants radio to send full node db to the phone, This is typically the first packet sent to the radio when the phone gets a bluetooth connection. The radio will respond by sending back a MyNodeInfo, a owner, a radio config and a series of FromRadio.node_infos, and config_complete the integer you write into this field will be reported back in the config_complete_id response this allows clients to never be confused by a stale old partially sent config.
set_radio	RadioConfig		set the radio provisioning for this node
set_owner	User		Set the owner for this node

User

Broadcast when a newly powered mesh node wants to find a node num it can use Sent from the phone over bluetooth to set the user id for the owner of this node. Also sent from nodes to each other when a new node signs on (so all clients can have this info)

The algorithm is as follows: when a node starts up, it broadcasts their user and the normal flow is for all other nodes to reply with their User as well (so the new node can build its node db) If a node ever receives a User (not just the first broadcast) message where the sender node number equals our node number, that indicates a collision has occurred and the following steps should happen:

If the receiving node (that was already in the mesh)'s macaddr is LOWER than the new User who just tried to sign in: it gets to keep its nodenum. We send a broadcast message of OUR User (we use a broadcast so that the other node can receive our message, considering we have the same id - it also serves to let observers correct their nodedb) - this case is rare so it should be okay.

If any node receives a User where the macaddr is GTE than their local macaddr, they have been vetoed and should pick a new random nodenum (filtering against whatever it knows about the nodedb) and rebroadcast their User.

A few nodenums are reserved and will never be requested: 0xff - broadcast 0 through 3 - for future use

Field	Type	Label	Description
id	string		a globally unique ID string for this user. In the case of
long_name	string		A full name for this user, i.e. "Kevin Hester"
short_name	string		A VERY short name, ideally two characters. Suitable
macaddr	bytes		This is the addr of the radio. Not populated by the

ChannelSettings.ModemConfig

Standard predefined channel settings Note: these mappings must match ModemConfigChoice in the device code.

Name	Number	Description
Bw125Cr45Sf128	0	< Bw = 125 kHz, Cr = 4/5, Sf = 128chips/symbol, CRC
Bw500Cr45Sf128	1	< Bw = 500 kHz, Cr = 4/5, Sf = 128chips/symbol, CRC
Bw31_25Cr48Sf512	2	< Bw = 31.25 kHz, Cr = 4/8, Sf = 512chips/symbol,
Bw125Cr48Sf4096	3	< Bw = 125 kHz, Cr = 4/8, Sf = 4096chips/symbol, CRC

Constants

Shared constants between device and phone

Name	Number	Description
Unused	0	First enum must be zero, and we are just using this enum to
DATA_PAYLOAD_LEN	240	From mesh.options note: this payload length is ONLY the bytes that are sent inside of the radiohead packet Data.payload max_size:240

GpsOperation

How the GPS hardware in this unit is operated.

Note: This is independent of how our location is shared with other devices. For that see LocationSharing

Name	Number	Description
GpsOpUnset	0	This is treated as GpsOpMobile - it is the default settting
GpsOpMobile	2	This node is mobile and we should get GPS position at a rate governed by gps_update_rate
GpsOpTimeOnly	3	We should only use the GPS to get time (no location data should be acquired/stored) Once we have the time we treat gps_update_interval as MAXINT (i.e. sleep forever)
GpsOpDisabled	4	GPS is always turned off - this mode is not recommended - use GpsOpTimeOnly instead

LocationSharing

How our location is shared with other nodes (or the local phone)

Name	Number	Description
LocUnset	0	This is the default and treated as LocEnabled)
LocEnabled	1	We are sharing our location
LocDisabled	2	We are not sharing our location (if the unit has a GPS it will default to only get time - i.e. GpsOpTimeOnly)

RegionCode

The frequency/regulatory region the user has selected.

Note: In 1.0 builds (which must still be supported by the android app for a long time) this field will be unpopulated.

If firmware is ever upgraded from an old 1.0ish build, the old MyNodeInfo.region string will be used to set UserPreferences.region and the old value will be no longer set.

Name	Number	Description
Unset	0
US	1
EU433	2
EU865	3
CN	4
JP	5
ANZ	6
KR	7
TW	8

RouteError

Name	Number	Description
NONE	0
NO_ROUTE	1	Our node doesn't have a route to the requested destination anymore.
GOT_NAK	2	We received a nak while trying to forward on your behalf
TIMEOUT	3

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portnums.proto

PortNum

For any new 'apps' that run on the device or via sister apps on phones/PCs they should pick and use a unique 'portnum' for their application.

If you are making a new app using meshtastic, please send in a pull request to add your 'portnum' to this master table. PortNums should be assigned in the following range:

0-63 Core Meshtastic use, do not use for third party apps 64-127 Registered 3rd party apps, send in a pull request that adds a new entry to portnums.proto to register your application 256-511 Use one of these portnums for your private applications that you don't want to register publically 1024-66559 Are reserved for use by IP tunneling (see FIXME for more information)

All other values are reserved.

Note: This was formerly a Type enum named 'typ' with the same id #

We have change to this 'portnum' based scheme for specifying app handlers for particular payloads.
This change is backwards compatible by treating the legacy OPAQUE/CLEAR_TEXT values identically.

Name	Number	Description
UNKNOWN_APP	0	Deprecated: do not use in new code (formerly called OPAQUE) A message sent from a device outside of the mesh, in a form the mesh does not understand NOTE: This must be 0, because it is documented in IMeshService.aidl to be so
TEXT_MESSAGE_APP	1	a simple UTF-8 text message, which even the little micros in the mesh can understand and show on their screen eventually in some circumstances even signal might send messages in this form (see below) Formerly called CLEAR_TEXT
POSITION_APP	3	The built-in position messaging app
GPIO_APP	2	Future standard app IDs
MESH_USERINFO_APP	4
PRIVATE_APP	256	Private applications should use portnums >= 256. To simplify initial development and testing you can use "PRIVATE_APP" in your code without needing to rebuild protobuf files (via bin/regin_protos.sh)
IP_TUNNEL_APP	1024

Scalar Value Types

.proto Type	Notes	C++	Java	Python	Go	C#	PHP	Ruby
double		double	double	float	float64	double	float	Float
float		float	float	float	float32	float	float	Float
int32	Uses variable-length encoding. Inefficient for encoding negative numbers – if your field is likely to have negative values, use sint32 instead.	int32	int	int	int32	int	integer	Bignum or Fixnum (as required)
int64	Uses variable-length encoding. Inefficient for encoding negative numbers – if your field is likely to have negative values, use sint64 instead.	int64	long	int/long	int64	long	integer/string	Bignum
uint32	Uses variable-length encoding.	uint32	int	int/long	uint32	uint	integer	Bignum or Fixnum (as required)
uint64	Uses variable-length encoding.	uint64	long	int/long	uint64	ulong	integer/string	Bignum or Fixnum (as required)
sint32	Uses variable-length encoding. Signed int value. These more efficiently encode negative numbers than regular int32s.	int32	int	int	int32	int	integer	Bignum or Fixnum (as required)
sint64	Uses variable-length encoding. Signed int value. These more efficiently encode negative numbers than regular int64s.	int64	long	int/long	int64	long	integer/string	Bignum
fixed32	Always four bytes. More efficient than uint32 if values are often greater than 2^28.	uint32	int	int	uint32	uint	integer	Bignum or Fixnum (as required)
fixed64	Always eight bytes. More efficient than uint64 if values are often greater than 2^56.	uint64	long	int/long	uint64	ulong	integer/string	Bignum
sfixed32	Always four bytes.	int32	int	int	int32	int	integer	Bignum or Fixnum (as required)
sfixed64	Always eight bytes.	int64	long	int/long	int64	long	integer/string	Bignum
bool		bool	boolean	boolean	bool	bool	boolean	TrueClass/FalseClass
string	A string must always contain UTF-8 encoded or 7-bit ASCII text.	string	String	str/unicode	string	string	string	String (UTF-8)
bytes	May contain any arbitrary sequence of bytes.	string	ByteString	str	[]byte	ByteString	string	String (ASCII-8BIT)