feat(mesh): add meshtastic serial radio support

core/archipelago/src/mesh/listener/session.rs

@@ -1,42 +1,140 @@
 //! Mesh session lifecycle: connect, initialize, main loop.
 
+use super::super::meshtastic::MeshtasticDevice;
 use super::super::serial::MeshcoreDevice;
 use super::super::types::*;
 use super::{
     frames, MeshCommand, MeshState, ADVERT_INTERVAL, MAX_CONSECUTIVE_WRITE_FAILURES, SYNC_INTERVAL,
 };
-use anyhow::Result;
+use anyhow::{Context, Result};
 use std::sync::Arc;
 use std::time::Duration;
 use tokio::sync::mpsc;
 use tracing::{debug, error, info, warn};
 
-/// Scan all candidate serial ports and open the first Meshcore device found.
+enum MeshRadioDevice {
-async fn auto_detect_and_open() -> Result<(String, MeshcoreDevice, DeviceInfo)> {
+    Meshcore(MeshcoreDevice),
+    Meshtastic(MeshtasticDevice),
+}
+
+impl MeshRadioDevice {
+    fn device_type(&self) -> DeviceType {
+        match self {
+            Self::Meshcore(_) => DeviceType::Meshcore,
+            Self::Meshtastic(_) => DeviceType::Meshtastic,
+        }
+    }
+
+    fn advert_name(&self) -> Option<String> {
+        match self {
+            Self::Meshcore(device) => device.advert_name.clone(),
+            Self::Meshtastic(device) => device.advert_name(),
+        }
+    }
+
+    async fn set_advert_name(&mut self, name: &str) -> Result<()> {
+        match self {
+            Self::Meshcore(device) => device.set_advert_name(name).await,
+            Self::Meshtastic(device) => device.set_advert_name(name).await,
+        }
+    }
+
+    async fn send_self_advert(&mut self) -> Result<()> {
+        match self {
+            Self::Meshcore(device) => device.send_self_advert().await,
+            Self::Meshtastic(device) => device.send_self_advert().await,
+        }
+    }
+
+    async fn send_channel_text(&mut self, channel: u8, payload: &[u8]) -> Result<()> {
+        match self {
+            Self::Meshcore(device) => device.send_channel_text(channel, payload).await,
+            Self::Meshtastic(device) => device.send_channel_text(channel, payload).await,
+        }
+    }
+
+    async fn get_contacts(&mut self) -> Result<Vec<super::super::protocol::ParsedContact>> {
+        match self {
+            Self::Meshcore(device) => device.get_contacts().await,
+            Self::Meshtastic(device) => device.get_contacts().await,
+        }
+    }
+
+    async fn reset_contact_path(&mut self, pubkey: &[u8; 32]) -> Result<()> {
+        match self {
+            Self::Meshcore(device) => device.reset_contact_path(pubkey).await,
+            Self::Meshtastic(device) => device.reset_contact_path(pubkey).await,
+        }
+    }
+
+    async fn sync_messages(&mut self) -> Result<Vec<super::super::protocol::InboundFrame>> {
+        match self {
+            Self::Meshcore(device) => device.sync_messages().await,
+            Self::Meshtastic(device) => device.sync_messages().await,
+        }
+    }
+
+    async fn try_recv_frame(&mut self) -> Result<Option<super::super::protocol::InboundFrame>> {
+        match self {
+            Self::Meshcore(device) => device.try_recv_frame().await,
+            Self::Meshtastic(device) => device.try_recv_frame().await,
+        }
+    }
+}
+
+/// Scan all candidate serial ports and open the first supported mesh device found.
+async fn auto_detect_and_open() -> Result<(String, MeshRadioDevice, DeviceInfo)> {
     let paths = super::super::serial::detect_serial_devices().await;
     if paths.is_empty() {
         anyhow::bail!("No serial devices found in /dev");
     }
     for path in &paths {
-        debug!(path = %path, "Probing for Meshcore device");
+        debug!(path = %path, "Probing for mesh radio device");
         match MeshcoreDevice::open(path).await {
             Ok(mut dev) => match dev.initialize().await {
                 Ok(info) => {
                     info!(path = %path, firmware = %info.firmware_version, "Found Meshcore device via auto-detect");
-                    return Ok((path.clone(), dev, info));
+                    return Ok((path.clone(), MeshRadioDevice::Meshcore(dev), info));
                 }
                 Err(e) => debug!(path = %path, error = %e, "Not a Meshcore device"),
             },
             Err(e) => debug!(path = %path, error = %e, "Could not open serial port"),
         }
+        match MeshtasticDevice::open(path).await {
+            Ok(mut dev) => match dev.initialize().await {
+                Ok(info) => {
+                    info!(path = %path, firmware = %info.firmware_version, "Found Meshtastic device via auto-detect");
+                    return Ok((path.clone(), MeshRadioDevice::Meshtastic(dev), info));
+                }
+                Err(e) => debug!(path = %path, error = %e, "Not a Meshtastic device"),
+            },
+            Err(e) => debug!(path = %path, error = %e, "Could not open serial port for Meshtastic"),
+        }
     }
     anyhow::bail!(
-        "No Meshcore device found on {} candidate ports: {:?}",
+        "No supported mesh radio found on {} candidate ports: {:?}",
         paths.len(),
         paths
     )
 }
 
+async fn open_preferred_path(path: &str) -> Result<(MeshRadioDevice, DeviceInfo)> {
+    match MeshcoreDevice::open(path).await {
+        Ok(mut dev) => match dev.initialize().await {
+            Ok(info) => return Ok((MeshRadioDevice::Meshcore(dev), info)),
+            Err(e) => debug!(path = %path, error = %e, "Preferred path is not Meshcore"),
+        },
+        Err(e) => debug!(path = %path, error = %e, "Could not open preferred path as Meshcore"),
+    }
+    match MeshtasticDevice::open(path).await {
+        Ok(mut dev) => match dev.initialize().await {
+            Ok(info) => Ok((MeshRadioDevice::Meshtastic(dev), info)),
+            Err(e) => Err(e).context("Preferred path is not Meshtastic"),
+        },
+        Err(e) => Err(e).context("Could not open preferred path as Meshtastic"),
+    }
+}
+
 /// ASCII marker for the original DM-via-channel format:
 /// `@DM:` + base64(`[dest_prefix(6)][inner…]`). No sender info on the wire,
 /// so the receiver has to guess the sender from its contact table — which
@@ -90,7 +188,7 @@ fn our_sender_prefix(state: &Arc<MeshState>) -> [u8; 6] {
 /// with both the recipient and sender prefixes so attribution works on
 /// the receiver side.
 async fn send_dm_via_channel(
-    device: &mut MeshcoreDevice,
+    device: &mut MeshRadioDevice,
     state: &Arc<MeshState>,
     dest_pubkey_prefix: &[u8; 6],
     payload: &[u8],
@@ -166,7 +264,7 @@ async fn send_dm_via_channel(
 }
 
 /// Fetch the contacts list from the device and update the peer cache.
-async fn refresh_contacts(device: &mut MeshcoreDevice, state: &Arc<MeshState>) {
+async fn refresh_contacts(device: &mut MeshRadioDevice, state: &Arc<MeshState>) {
     match device.get_contacts().await {
         Ok(contacts) => {
             // Skip firmware contacts the user has explicitly wiped via
@@ -239,7 +337,7 @@ async fn refresh_contacts(device: &mut MeshcoreDevice, state: &Arc<MeshState>) {
 /// Drain any queued messages from the device.
 /// Returns `true` if a write/communication error occurred (for failure tracking).
 async fn sync_queued_messages(
-    device: &mut MeshcoreDevice,
+    device: &mut MeshRadioDevice,
     state: &Arc<MeshState>,
     our_x25519_secret: &[u8; 32],
 ) -> bool {
@@ -274,20 +372,11 @@ pub(super) async fn run_mesh_session(
 ) -> Result<()> {
     // Detect device — try preferred path first, fall back to auto-detect
     let (device_path, mut device, device_info) = if let Some(path) = preferred_path {
-        match MeshcoreDevice::open(path).await {
+        match open_preferred_path(path).await {
-            Ok(mut dev) => match dev.initialize().await {
+            Ok((dev, info)) => (path.to_string(), dev, info),
-                Ok(info) => (path.to_string(), dev, info),
             Err(e) => {
                 warn!(
-                        "Preferred path {} handshake failed: {} — trying auto-detect",
+                    "Preferred path {} probe failed: {} — trying auto-detect",
-                        path, e
-                    );
-                    auto_detect_and_open().await?
-                }
-            },
-            Err(e) => {
-                warn!(
-                    "Preferred path {} open failed: {} — trying auto-detect",
                     path, e
                 );
                 auto_detect_and_open().await?
@@ -301,11 +390,11 @@ pub(super) async fn run_mesh_session(
     {
         let mut status = state.status.write().await;
         status.device_connected = true;
-        status.device_type = DeviceType::Meshcore;
+        status.device_type = device.device_type();
         status.device_path = Some(device_path.clone());
         status.firmware_version = Some(device_info.firmware_version.clone());
         status.self_node_id = Some(device_info.node_id);
-        status.self_advert_name = device.advert_name.clone();
+        status.self_advert_name = device.advert_name();
     }
 
     let _ = state.event_tx.send(MeshEvent::DeviceConnected(device_info));
@@ -434,7 +523,7 @@ pub(super) async fn run_mesh_session(
 /// Process a single outbound command from MeshService.
 async fn handle_send_command(
     cmd: MeshCommand,
-    device: &mut MeshcoreDevice,
+    device: &mut MeshRadioDevice,
     state: &Arc<MeshState>,
     consecutive_write_failures: &mut u32,
 ) {

core/archipelago/src/mesh/meshtastic.rs

@@ -0,0 +1,577 @@
+//! Async serial driver for Meshtastic devices.
+//!
+//! Meshtastic uses protobuf payloads over a SLIP-like serial stream. This
+//! module implements only the small subset Archipelago needs: connect,
+//! discover the local node, send/receive text packets, and provide synthetic
+//! contacts to the existing mesh listener.
+
+use super::protocol::{InboundFrame, ParsedContact};
+use super::types::{DeviceInfo, DeviceType};
+use anyhow::{Context, Result};
+use std::collections::HashMap;
+use std::time::Duration;
+use tracing::{debug, info, warn};
+
+const BAUD_RATE: u32 = 115200;
+const READ_TIMEOUT: Duration = Duration::from_secs(5);
+const WRITE_TIMEOUT: Duration = Duration::from_secs(2);
+const READ_BUF_SIZE: usize = 512;
+
+const START1: u8 = 0x94;
+const START2: u8 = 0xc3;
+const TO_RADIO_MAX: usize = 512;
+const BROADCAST_NUM: u32 = 0xffff_ffff;
+const TEXT_MESSAGE_APP: u32 = 1;
+
+const TO_RADIO_PACKET: u64 = 1;
+const TO_RADIO_WANT_CONFIG_ID: u64 = 3;
+const TO_RADIO_HEARTBEAT: u64 = 7;
+
+const FROM_RADIO_PACKET: u64 = 2;
+const FROM_RADIO_MY_INFO: u64 = 3;
+const FROM_RADIO_NODE_INFO: u64 = 4;
+const FROM_RADIO_CONFIG_COMPLETE_ID: u64 = 7;
+const FROM_RADIO_REBOOTED: u64 = 8;
+
+/// Async Meshtastic device handle.
+pub struct MeshtasticDevice {
+    port: serial2_tokio::SerialPort,
+    read_buf: Vec<u8>,
+    node_num: Option<u32>,
+    user_id: Option<String>,
+    long_name: Option<String>,
+    short_name: Option<String>,
+    contacts: HashMap<u32, ParsedContact>,
+    device_path: String,
+}
+
+impl MeshtasticDevice {
+    pub async fn open(path: &str) -> Result<Self> {
+        match tokio::fs::metadata(path).await {
+            Ok(meta) => debug!(path = %path, permissions = ?meta.permissions(), "Device node exists"),
+            Err(e) => anyhow::bail!("Serial device {} not accessible: {}", path, e),
+        }
+
+        let port = serial2_tokio::SerialPort::open(path, BAUD_RATE).context(format!(
+            "Failed to open serial port {} (permission denied? device busy?)",
+            path
+        ))?;
+        info!(path = %path, baud = BAUD_RATE, "Opened Meshtastic serial port");
+
+        Ok(Self {
+            port,
+            read_buf: Vec::with_capacity(READ_BUF_SIZE),
+            node_num: None,
+            user_id: None,
+            long_name: None,
+            short_name: None,
+            contacts: HashMap::new(),
+            device_path: path.to_string(),
+        })
+    }
+
+    pub async fn initialize(&mut self) -> Result<DeviceInfo> {
+        info!(path = %self.device_path, "Starting Meshtastic handshake");
+        self.send_to_radio(&encode_want_config()).await?;
+
+        let deadline = tokio::time::Instant::now() + READ_TIMEOUT;
+        let mut saw_meshtastic_frame = false;
+
+        loop {
+            let remaining = deadline.saturating_duration_since(tokio::time::Instant::now());
+            if remaining.is_zero() {
+                break;
+            }
+            match tokio::time::timeout(remaining.min(Duration::from_millis(250)), self.read_from_radio()).await {
+                Ok(Ok(Some(frame))) => {
+                    saw_meshtastic_frame = true;
+                    self.handle_from_radio(&frame);
+                    if self.node_num.is_some() && self.user_id.is_some() {
+                        break;
+                    }
+                }
+                Ok(Ok(None)) | Err(_) => {}
+                Ok(Err(e)) => return Err(e),
+            }
+        }
+
+        if !saw_meshtastic_frame {
+            anyhow::bail!("No Meshtastic serial API response");
+        }
+
+        let node_id = self.node_num.unwrap_or(0);
+        let firmware_version = self
+            .long_name
+            .clone()
+            .or_else(|| self.user_id.clone())
+            .unwrap_or_else(|| "Meshtastic".to_string());
+
+        info!(node_id, name = %firmware_version, "Meshtastic identity");
+        Ok(DeviceInfo {
+            firmware_version,
+            node_id,
+            max_contacts: 200,
+            device_type: DeviceType::Meshtastic,
+        })
+    }
+
+    pub async fn set_advert_name(&mut self, name: &str) -> Result<()> {
+        self.long_name = Some(name.to_string());
+        Ok(())
+    }
+
+    pub async fn send_self_advert(&mut self) -> Result<()> {
+        self.send_to_radio(&encode_heartbeat()).await
+    }
+
+    pub async fn send_channel_text(&mut self, _channel: u8, msg: &[u8]) -> Result<()> {
+        let text = String::from_utf8_lossy(msg);
+        let packet = encode_mesh_packet(BROADCAST_NUM, TEXT_MESSAGE_APP, text.as_bytes());
+        self.send_to_radio(&encode_to_radio_variant(TO_RADIO_PACKET, &packet))
+            .await
+    }
+
+    pub async fn get_contacts(&mut self) -> Result<Vec<ParsedContact>> {
+        Ok(self.contacts.values().cloned().collect())
+    }
+
+    pub async fn reset_contact_path(&mut self, _pubkey: &[u8; 32]) -> Result<()> {
+        Ok(())
+    }
+
+    pub async fn sync_messages(&mut self) -> Result<Vec<InboundFrame>> {
+        Ok(Vec::new())
+    }
+
+    pub async fn try_recv_frame(&mut self) -> Result<Option<InboundFrame>> {
+        let Some(frame) = self.read_from_radio().await? else {
+            return Ok(None);
+        };
+        Ok(self.handle_from_radio(&frame))
+    }
+
+    pub fn advert_name(&self) -> Option<String> {
+        self.long_name
+            .clone()
+            .or_else(|| self.short_name.clone())
+            .or_else(|| self.user_id.clone())
+    }
+
+    async fn send_to_radio(&mut self, payload: &[u8]) -> Result<()> {
+        if payload.len() > TO_RADIO_MAX {
+            anyhow::bail!("Meshtastic payload too large: {} bytes", payload.len());
+        }
+        let mut frame = Vec::with_capacity(4 + payload.len());
+        frame.push(START1);
+        frame.push(START2);
+        frame.extend_from_slice(&(payload.len() as u16).to_be_bytes());
+        frame.extend_from_slice(payload);
+        tokio::time::timeout(WRITE_TIMEOUT, self.port.write_all(&frame))
+            .await
+            .context("Meshtastic serial write timed out")?
+            .context("Meshtastic serial write failed")?;
+        Ok(())
+    }
+
+    async fn read_from_radio(&mut self) -> Result<Option<Vec<u8>>> {
+        if let Some(frame) = decode_serial_frame(&mut self.read_buf) {
+            return Ok(Some(frame));
+        }
+
+        let mut tmp = [0u8; READ_BUF_SIZE];
+        match tokio::time::timeout(Duration::from_millis(50), self.port.read(&mut tmp)).await {
+            Ok(Ok(0)) => anyhow::bail!("Meshtastic serial port closed"),
+            Ok(Ok(n)) => self.read_buf.extend_from_slice(&tmp[..n]),
+            Ok(Err(e)) => return Err(e).context("Meshtastic serial read error"),
+            Err(_) => return Ok(None),
+        }
+
+        Ok(decode_serial_frame(&mut self.read_buf))
+    }
+
+    fn handle_from_radio(&mut self, frame: &[u8]) -> Option<InboundFrame> {
+        let Some((field, value)) = decode_top_level_variant(frame) else {
+            return None;
+        };
+        match field {
+            FROM_RADIO_MY_INFO => {
+                if let Some((node_num, user_id)) = parse_my_info(value) {
+                    self.node_num = Some(node_num);
+                    if let Some(user_id) = user_id {
+                        self.user_id = Some(user_id);
+                    }
+                }
+                None
+            }
+            FROM_RADIO_NODE_INFO => {
+                self.update_node_info(value);
+                None
+            }
+            FROM_RADIO_PACKET => self.packet_to_inbound_frame(value),
+            FROM_RADIO_CONFIG_COMPLETE_ID | FROM_RADIO_REBOOTED => None,
+            other => {
+                debug!(field = other, len = value.len(), "Unhandled Meshtastic FromRadio field");
+                None
+            }
+        }
+    }
+
+    fn update_node_info(&mut self, data: &[u8]) {
+        if let Some(node) = parse_node_info(data) {
+            let key = synthetic_pubkey(node.num);
+            let name = node
+                .long_name
+                .or(node.short_name)
+                .or(node.id)
+                .unwrap_or_else(|| format!("Meshtastic !{:08x}", node.num));
+            if Some(node.num) == self.node_num {
+                self.long_name = Some(name.clone());
+            }
+            self.contacts.insert(
+                node.num,
+                ParsedContact {
+                    public_key_hex: hex::encode(key),
+                    advert_name: name,
+                    last_advert: node.last_heard.unwrap_or_default(),
+                    contact_type: 1,
+                    path_len: 0xff,
+                    flags: 0,
+                },
+            );
+        }
+    }
+
+    fn packet_to_inbound_frame(&mut self, data: &[u8]) -> Option<InboundFrame> {
+        let packet = parse_mesh_packet(data)?;
+        if packet.portnum != TEXT_MESSAGE_APP || packet.payload.is_empty() {
+            return None;
+        }
+        let from = packet.from.unwrap_or(0);
+        if Some(from) == self.node_num {
+            return None;
+        }
+        let from_key = synthetic_pubkey(from);
+        self.contacts.entry(from).or_insert_with(|| ParsedContact {
+            public_key_hex: hex::encode(synthetic_pubkey(from)),
+            advert_name: format!("Meshtastic !{:08x}", from),
+            last_advert: 0,
+            contact_type: 1,
+            path_len: 0xff,
+            flags: 0,
+        });
+
+        let mut payload = Vec::with_capacity(15 + packet.payload.len());
+        payload.push(0); // SNR unknown
+        payload.extend_from_slice(&[0, 0]); // reserved
+        payload.extend_from_slice(&from_key[..6]);
+        payload.push(0xff); // unknown/flood path
+        payload.push(0); // text type
+        payload.extend_from_slice(&0u32.to_le_bytes());
+        payload.extend_from_slice(&packet.payload);
+        Some(InboundFrame {
+            code: super::protocol::RESP_CONTACT_MSG_V3,
+            data: payload,
+            bytes_consumed: 0,
+        })
+    }
+}
+
+fn decode_serial_frame(buf: &mut Vec<u8>) -> Option<Vec<u8>> {
+    let start = buf.windows(2).position(|w| w == [START1, START2])?;
+    if start > 0 {
+        buf.drain(..start);
+    }
+    if buf.len() < 4 {
+        return None;
+    }
+    let len = u16::from_be_bytes([buf[2], buf[3]]) as usize;
+    if buf.len() < 4 + len {
+        return None;
+    }
+    let payload = buf[4..4 + len].to_vec();
+    buf.drain(..4 + len);
+    Some(payload)
+}
+
+fn encode_want_config() -> Vec<u8> {
+    encode_to_radio_variant(TO_RADIO_WANT_CONFIG_ID, &encode_varint_field(1, 1))
+}
+
+fn encode_heartbeat() -> Vec<u8> {
+    encode_to_radio_variant(TO_RADIO_HEARTBEAT, &[])
+}
+
+fn encode_to_radio_variant(field: u64, bytes: &[u8]) -> Vec<u8> {
+    let mut out = Vec::new();
+    encode_len_field(field, bytes, &mut out);
+    out
+}
+
+fn encode_mesh_packet(to: u32, portnum: u32, payload: &[u8]) -> Vec<u8> {
+    let mut decoded = Vec::new();
+    encode_varint_field_into(1, portnum as u64, &mut decoded);
+    encode_len_field(2, payload, &mut decoded);
+
+    let mut packet = Vec::new();
+    encode_fixed32_field(2, to, &mut packet);
+    encode_len_field(4, &decoded, &mut packet);
+    packet
+}
+
+fn decode_top_level_variant(buf: &[u8]) -> Option<(u64, &[u8])> {
+    let mut idx = 0;
+    while idx < buf.len() {
+        let (key, n) = read_varint(&buf[idx..])?;
+        idx += n;
+        let field = key >> 3;
+        match key & 0x07 {
+            0 => {
+                let (_, n) = read_varint(&buf[idx..])?;
+                idx += n;
+            }
+            2 => {
+                let (len, n) = read_varint(&buf[idx..])?;
+                idx += n;
+                let end = idx.checked_add(len as usize)?;
+                if end > buf.len() {
+                    return None;
+                }
+                if matches!(field, FROM_RADIO_PACKET | FROM_RADIO_MY_INFO | FROM_RADIO_NODE_INFO) {
+                    return Some((field, &buf[idx..end]));
+                }
+                idx = end;
+            }
+            _ => return None,
+        }
+    }
+    None
+}
+
+fn parse_my_info(data: &[u8]) -> Option<(u32, Option<String>)> {
+    let mut idx = 0;
+    let mut node_num = None;
+    let mut user_id = None;
+    while idx < data.len() {
+        let (field, value, next) = next_field(data, idx)?;
+        idx = next;
+        match (field, value) {
+            (1, FieldValue::Varint(v)) => node_num = Some(v as u32),
+            (1, FieldValue::Fixed32(v)) => node_num = Some(v),
+            (3, FieldValue::Bytes(b)) => user_id = parse_user(b).and_then(|u| u.id),
+            _ => {}
+        }
+    }
+    node_num.map(|n| (n, user_id))
+}
+
+struct ParsedNode {
+    num: u32,
+    id: Option<String>,
+    long_name: Option<String>,
+    short_name: Option<String>,
+    last_heard: Option<u32>,
+}
+
+fn parse_node_info(data: &[u8]) -> Option<ParsedNode> {
+    let mut idx = 0;
+    let mut node = ParsedNode {
+        num: 0,
+        id: None,
+        long_name: None,
+        short_name: None,
+        last_heard: None,
+    };
+    while idx < data.len() {
+        let (field, value, next) = next_field(data, idx)?;
+        idx = next;
+        match (field, value) {
+            (1, FieldValue::Varint(v)) => node.num = v as u32,
+            (1, FieldValue::Fixed32(v)) => node.num = v,
+            (2, FieldValue::Bytes(b)) => {
+                if let Some(user) = parse_user(b) {
+                    node.id = user.id;
+                    node.long_name = user.long_name;
+                    node.short_name = user.short_name;
+                }
+            }
+            (5, FieldValue::Fixed32(v)) => node.last_heard = Some(v),
+            _ => {}
+        }
+    }
+    if node.num == 0 {
+        None
+    } else {
+        Some(node)
+    }
+}
+
+struct ParsedUser {
+    id: Option<String>,
+    long_name: Option<String>,
+    short_name: Option<String>,
+}
+
+fn parse_user(data: &[u8]) -> Option<ParsedUser> {
+    let mut idx = 0;
+    let mut user = ParsedUser {
+        id: None,
+        long_name: None,
+        short_name: None,
+    };
+    while idx < data.len() {
+        let (field, value, next) = next_field(data, idx)?;
+        idx = next;
+        match (field, value) {
+            (1, FieldValue::Bytes(b)) => user.id = string_field(b),
+            (2, FieldValue::Bytes(b)) => user.long_name = string_field(b),
+            (3, FieldValue::Bytes(b)) => user.short_name = string_field(b),
+            _ => {}
+        }
+    }
+    Some(user)
+}
+
+struct ParsedPacket {
+    from: Option<u32>,
+    portnum: u32,
+    payload: Vec<u8>,
+}
+
+fn parse_mesh_packet(data: &[u8]) -> Option<ParsedPacket> {
+    let mut idx = 0;
+    let mut from = None;
+    let mut decoded = None;
+    while idx < data.len() {
+        let (field, value, next) = next_field(data, idx)?;
+        idx = next;
+        match (field, value) {
+            (1, FieldValue::Fixed32(v)) => from = Some(v),
+            (4, FieldValue::Bytes(b)) => decoded = Some(b),
+            _ => {}
+        }
+    }
+    let decoded = decoded?;
+    let mut didx = 0;
+    let mut portnum = 0;
+    let mut payload = Vec::new();
+    while didx < decoded.len() {
+        let (field, value, next) = next_field(decoded, didx)?;
+        didx = next;
+        match (field, value) {
+            (1, FieldValue::Varint(v)) => portnum = v as u32,
+            (2, FieldValue::Bytes(b)) => payload = b.to_vec(),
+            _ => {}
+        }
+    }
+    Some(ParsedPacket {
+        from,
+        portnum,
+        payload,
+    })
+}
+
+enum FieldValue<'a> {
+    Varint(u64),
+    Fixed32(u32),
+    Bytes(&'a [u8]),
+}
+
+fn next_field(buf: &[u8], idx: usize) -> Option<(u64, FieldValue<'_>, usize)> {
+    let (key, n) = read_varint(&buf[idx..])?;
+    let field = key >> 3;
+    let mut pos = idx + n;
+    match key & 0x07 {
+        0 => {
+            let (v, n) = read_varint(&buf[pos..])?;
+            pos += n;
+            Some((field, FieldValue::Varint(v), pos))
+        }
+        2 => {
+            let (len, n) = read_varint(&buf[pos..])?;
+            pos += n;
+            let end = pos.checked_add(len as usize)?;
+            if end > buf.len() {
+                return None;
+            }
+            Some((field, FieldValue::Bytes(&buf[pos..end]), end))
+        }
+        5 => {
+            let end = pos.checked_add(4)?;
+            if end > buf.len() {
+                None
+            } else {
+                let value = u32::from_le_bytes([
+                    buf[pos],
+                    buf[pos + 1],
+                    buf[pos + 2],
+                    buf[pos + 3],
+                ]);
+                Some((field, FieldValue::Fixed32(value), end))
+            }
+        }
+        1 => {
+            let end = pos.checked_add(8)?;
+            if end > buf.len() {
+                None
+            } else {
+                Some((field, FieldValue::Bytes(&buf[pos..end]), end))
+            }
+        }
+        wire => {
+            warn!(wire, "Unsupported Meshtastic protobuf wire type");
+            None
+        }
+    }
+}
+
+fn read_varint(buf: &[u8]) -> Option<(u64, usize)> {
+    let mut out = 0u64;
+    for (i, b) in buf.iter().copied().enumerate().take(10) {
+        out |= ((b & 0x7f) as u64) << (7 * i);
+        if b & 0x80 == 0 {
+            return Some((out, i + 1));
+        }
+    }
+    None
+}
+
+fn encode_varint_field(field: u64, value: u64) -> Vec<u8> {
+    let mut out = Vec::new();
+    encode_varint_field_into(field, value, &mut out);
+    out
+}
+
+fn encode_varint_field_into(field: u64, value: u64, out: &mut Vec<u8>) {
+    write_varint((field << 3) | 0, out);
+    write_varint(value, out);
+}
+
+fn encode_len_field(field: u64, bytes: &[u8], out: &mut Vec<u8>) {
+    write_varint((field << 3) | 2, out);
+    write_varint(bytes.len() as u64, out);
+    out.extend_from_slice(bytes);
+}
+
+fn encode_fixed32_field(field: u64, value: u32, out: &mut Vec<u8>) {
+    write_varint((field << 3) | 5, out);
+    out.extend_from_slice(&value.to_le_bytes());
+}
+
+fn write_varint(mut value: u64, out: &mut Vec<u8>) {
+    while value >= 0x80 {
+        out.push((value as u8 & 0x7f) | 0x80);
+        value >>= 7;
+    }
+    out.push(value as u8);
+}
+
+fn string_field(bytes: &[u8]) -> Option<String> {
+    std::str::from_utf8(bytes).ok().map(|s| s.to_string())
+}
+
+fn synthetic_pubkey(node_num: u32) -> [u8; 32] {
+    let mut out = [0u8; 32];
+    out[..4].copy_from_slice(&node_num.to_le_bytes());
+    out[4..15].copy_from_slice(b"meshtastic:");
+    out
+}

core/archipelago/src/mesh/mod.rs

@@ -1,13 +1,15 @@
-//! Mesh networking: Meshcore LoRa radio integration for offline peer discovery
+//! Mesh networking: LoRa radio integration for offline peer discovery
 //! and encrypted messaging between Archipelago nodes.
 //!
-//! Supports Meshcore firmware on Heltec V3, T-Beam, RAK WisBlock, Station G2,
+//! Supports Meshcore firmware via Companion USB and Meshtastic firmware via
-//! and other ESP32/nRF52-based LoRa boards via USB serial (Companion USB mode).
+//! the Meshtastic serial API on Heltec, T-Beam, RAK WisBlock, Station G2,
+//! and other ESP32/nRF52-based LoRa boards.
 
 pub mod alerts;
 pub mod bitcoin_relay;
 pub mod crypto;
 pub mod listener;
+pub mod meshtastic;
 pub mod message_types;
 pub mod outbox;
 pub mod protocol;

core/archipelago/src/mesh/protocol.rs

@@ -323,6 +323,7 @@ pub fn parse_self_info(data: &[u8]) -> Result<(u32, String)> {
 }
 
 /// Parsed contact from RESP_CONTACT (0x03).
+#[derive(Clone)]
 pub struct ParsedContact {
     pub public_key_hex: String,
     pub advert_name: String,

image-recipe/configs/99-mesh-radio.rules

@@ -1,6 +1,8 @@
 # Stable symlink for USB serial adapters used as mesh radios.
 # Creates /dev/mesh-radio pointing to the underlying ttyUSB device.
-# Supports: CP2102 (Heltec V3), CH340 (T-Beam), FTDI (RAK WisBlock).
+# Supports MeshCore and Meshtastic radios using CP2102 (Heltec V3),
+# CH340 (T-Beam), FTDI (RAK WisBlock), and USB CDC ACM devices.
 SUBSYSTEM=="tty", ATTRS{idVendor}=="10c4", ATTRS{idProduct}=="ea60", SYMLINK+="mesh-radio", MODE="0660", GROUP="dialout"
 SUBSYSTEM=="tty", ATTRS{idVendor}=="1a86", ATTRS{idProduct}=="7523", SYMLINK+="mesh-radio", MODE="0660", GROUP="dialout"
 SUBSYSTEM=="tty", ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6001", SYMLINK+="mesh-radio", MODE="0660", GROUP="dialout"
+SUBSYSTEM=="tty", KERNEL=="ttyACM[0-9]*", SYMLINK+="mesh-radio", MODE="0660", GROUP="dialout"