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use crate::atp::Atp;
use crate::ddp::DdpHandle;
use crate::nbp::{NbpHandle, RegisteredName};
use anyhow::Result;
use tailtalk_packets::asp::{AspHeader, SPFunction};
use tailtalk_packets::nbp::EntityName;
use tokio::task;
use tokio::time::{Duration, interval};
pub struct Asp;
use tokio::sync::{mpsc, oneshot};
/// Represents an incoming ASP command from a client
#[derive(Debug)]
pub struct AspCommand {
/// The sequence number of the command that initiated this transaction
pub sequence_number: u16,
/// The source address of the client that sent this command
pub client_address: crate::atp::AtpAddress,
/// The command data payload
pub data: Vec<u8>,
/// Maximum bytes the client can receive in the ATP response for this command.
/// Derived from the ATP TReq bitmap. AFP handlers must not send more than this.
pub atp_max_response_bytes: usize,
/// Channel to send the reply back to the client
reply_tx: oneshot::Sender<AspCommandResponse>,
}
#[derive(Debug)]
pub struct AspCommandResponse {
/// CmdResult code transported in the ATP user bytes
pub result: [u8; 4],
/// Optional response payload
pub data: Vec<u8>,
}
impl AspCommand {
/// Send a reply to this command
pub fn send_reply(self, reply_data: AspCommandResponse) -> Result<()> {
self.reply_tx
.send(reply_data)
.map_err(|_| anyhow::anyhow!("Failed to send reply"))
}
}
#[derive(Debug, Clone)]
pub struct AspHandle {
accept_tx: mpsc::Sender<oneshot::Sender<AspSession>>,
}
impl AspHandle {
/// Wait for the next incoming session.
pub async fn get_session(&self) -> Result<AspSession> {
let (tx, rx) = oneshot::channel();
self.accept_tx
.send(tx)
.await
.map_err(|_| anyhow::anyhow!("ASP task is dead"))?;
let session = rx.await?;
Ok(session)
}
}
// Session state: SessionID -> AspSession (Internal State tracking)
struct AspState {
addr: crate::atp::AtpAddress,
/// Fixed socket from OpenSess — used for server-initiated messages (Tickle, WriteContinue).
session_addr: crate::atp::AtpAddress,
#[allow(dead_code)]
match_addr_only: bool, // For future strict checking
// Channel to send commands to the session owner
command_tx: mpsc::Sender<AspCommand>,
last_activity: tokio::time::Instant,
}
// Public handle for a connected session (returned to user)
#[derive(Debug)]
pub struct AspSession {
pub id: u8,
pub remote_addr: crate::atp::AtpAddress,
/// Fixed socket from OpenSess — server-initiated requests (WriteContinue) go here.
session_addr: crate::atp::AtpAddress,
command_rx: mpsc::Receiver<AspCommand>,
atp_req: crate::atp::AtpRequestor,
}
impl AspSession {
/// Wait for the next incoming command on this session
pub async fn get_command(&mut self) -> Option<AspCommand> {
let cmd = self.command_rx.recv().await?;
// Update our remote_addr in case the client changed its socket after OpenSess
if self.remote_addr != cmd.client_address {
tracing::info!(
"ASP Session {} remote address updated from {:?} to {:?}",
self.id,
self.remote_addr,
cmd.client_address
);
self.remote_addr = cmd.client_address;
}
Some(cmd)
}
/// Perform a Write transaction to read data from the client
pub async fn write(&mut self, req_count: usize, sequence_number: u16) -> Result<Vec<u8>> {
// SPWrite Logic:
// Server sends ATP Request with SPWrite/WriteContinue function and available buffer size.
// Client responds with the data.
// If we limit the size to a chunk (like 1024 or 4624), we should NOT loop.
// We just do one transaction, return the data, and let the AFP layer reply with the
// actual bytes written. The client will issue a new FPWrite for the rest.
let chunk_size = req_count.min(crate::atp::ATP_MAX_DATA_PER_PACKET * 8);
let quantum = chunk_size as u16;
let header = AspHeader {
function: SPFunction::WriteContinue,
session_id: self.id,
sequence_number, // The sequence number of the original FPWrite command
};
let mut user_bytes = [0u8; 4];
header
.to_bytes(&mut user_bytes)
.map_err(|e| anyhow::anyhow!("ASP header error: {:?}", e))?;
// Data payload for SPWrite/WriteContinue request:
let mut data = Vec::with_capacity(2);
data.extend_from_slice(&quantum.to_be_bytes());
tracing::info!(
"ASP Session {} initiating WriteContinue, quantum={}",
self.id,
quantum
);
// Send ATP Request
let (response_data, _response_user_bytes) = self
.atp_req
.send_request(self.session_addr, user_bytes, data)
.await?;
Ok(response_data)
}
}
impl Asp {
pub async fn bind(
ddp: &DdpHandle,
nbp: &NbpHandle,
socket_number: Option<u8>,
entity_name: EntityName,
status_data: Vec<u8>,
) -> Result<AspHandle> {
let (actual_socket, atp_req, mut atp_resp) = Atp::spawn(ddp, socket_number).await;
nbp.register(RegisteredName {
name: entity_name,
sock_num: actual_socket,
})
.await?;
// Internal session state map
let mut sessions: std::collections::HashMap<u8, AspState> =
std::collections::HashMap::new();
let mut next_session_id: u8 = 1;
// Channel for user to accept sessions
let (accept_tx, mut accept_rx) = mpsc::channel::<oneshot::Sender<AspSession>>(10);
let atp_req_clone = atp_req.clone();
task::spawn(async move {
let mut tickle_interval = interval(Duration::from_secs(30));
// The first tick fires immediately; skip it so we don't tickle on startup.
tickle_interval.tick().await;
loop {
tokio::select! {
// ── Incoming ATP request ─────────────────────────────────────
maybe_req = atp_resp.next() => {
let Some(req) = maybe_req else { break };
// Parse user bytes for ASP header / command
// User bytes are [Function, SessionID, SequenceNumHi, SequenceNumLo]
let header = match AspHeader::parse(&req.user_bytes) {
Ok(h) => h,
Err(e) => {
tracing::warn!("ASP: failed to parse user_bytes {:?}: {:?}", req.user_bytes, e);
continue;
}
};
{
match header.function {
SPFunction::GetStatus => {
tracing::info!("ASP responding to GetStatus request");
// ASP response user bytes should be:
// [ResultCode, SessionID, SequenceHi, SequenceLo]
let response_user_bytes = [
0, // Result code 0 = success
header.session_id,
(header.sequence_number >> 8) as u8,
(header.sequence_number & 0xFF) as u8,
];
let _ = req
.send_response(status_data.clone(), response_user_bytes)
.await;
}
SPFunction::OpenSess => {
// Only accept if there is a pending acceptor
if let Ok(acceptor) = accept_rx.try_recv() {
let session_id = next_session_id;
// wrap around skipping 0
next_session_id = if next_session_id == 255 {
1
} else {
next_session_id + 1
};
// user_bytes[1] of OpenSess is the client's CSS (Client Session
// Socket) — the fixed socket where the client wants to receive
// server-initiated messages (WriteContinue, Tickle). This is NOT
// the source socket of this TReq (which is a dynamic socket).
let client_css = crate::atp::AtpAddress {
network_number: req.source.network_number,
node_number: req.source.node_number,
socket_number: header.session_id,
};
tracing::info!(
"ASP Opening Session {} for client {:?}, CSS={:?}",
session_id,
req.source,
client_css,
);
// Create command channel for this session
let (command_tx, command_rx) = mpsc::channel::<AspCommand>(10);
sessions.insert(
session_id,
AspState {
addr: req.source,
session_addr: client_css,
match_addr_only: true,
command_tx,
last_activity: tokio::time::Instant::now(),
},
);
// Notify user
let _ = acceptor.send(AspSession {
id: session_id,
remote_addr: req.source,
session_addr: client_css,
command_rx,
atp_req: atp_req_clone.clone(),
});
// Respond Success
let response_user_bytes = [
actual_socket, // Socket number for the remote side to talk to this new session on
session_id, // New Session ID
0,
0,
];
let _ = req.send_response(vec![], response_user_bytes).await;
} else {
tracing::warn!(
"ASP ServerBusy: No pending accept for OpenSess from {:?}",
req.source
);
// Respond with ServerBusy error (-1071 => 0xFBD1)
let err = tailtalk_packets::asp::ASP_SERVER_BUSY;
let _err_bytes = err.to_be_bytes();
let response_user_bytes = err.to_be_bytes();
let _ = req.send_response(vec![], response_user_bytes).await;
}
}
SPFunction::CloseSess => {
let session_id = header.session_id;
if let Some(sess) = sessions.get(&session_id) {
// Match on node identity only (network + node number), ignoring
// socket. Clients open on socket X, commands arrive from X+1
// (updating sess.addr), then CloseSess arrives from X again.
if sess.addr.network_number == req.source.network_number
&& sess.addr.node_number == req.source.node_number
{
tracing::info!("ASP Closing Session {}", session_id);
sessions.remove(&session_id);
// Respond Success
let response_user_bytes = [0, session_id, 0, 0];
let _ = req.send_response(vec![], response_user_bytes).await;
} else {
tracing::warn!(
"ASP CloseSess mismatch: Session {} owned by {:?}, req from {:?} — closing anyway",
session_id,
sess.addr,
req.source
);
sessions.remove(&session_id);
let response_user_bytes = [0, session_id, 0, 0];
let _ = req.send_response(vec![], response_user_bytes).await;
}
} else {
tracing::warn!("ASP CloseSess: Session {} not found", session_id);
// Respond Success anyway to clear client state
let response_user_bytes = [0, session_id, 0, 0];
let _ = req.send_response(vec![], response_user_bytes).await;
}
}
SPFunction::Command | SPFunction::Write => {
let session_id = header.session_id;
if let Some(sess) = sessions.get_mut(&session_id) {
sess.last_activity = tokio::time::Instant::now();
// Verify command is from the session owner (only check net+node, ignore socket)
if sess.addr.network_number == req.source.network_number
&& sess.addr.node_number == req.source.node_number
{
tracing::debug!(
"ASP Command/Write received for session {}, {} bytes",
session_id,
req.data.len()
);
// Update session address if the socket changed (Macs may open on port X and send commands from port Y)
if sess.addr != req.source {
tracing::debug!(
"ASP Session {} updating address from {:?} to {:?}",
session_id,
sess.addr,
req.source
);
sess.addr = req.source;
}
// Create reply channel
let (reply_tx, reply_rx) = oneshot::channel();
// Send command to session owner
let command = AspCommand {
sequence_number: header.sequence_number,
client_address: req.source,
data: req.data.clone(),
atp_max_response_bytes: req.max_response_bytes(),
reply_tx,
};
if sess.command_tx.send(command).await.is_ok() {
// Wait for reply from application
if let Ok(reply_data) = reply_rx.await {
let _ = req
.send_response(reply_data.data, reply_data.result)
.await;
} else {
tracing::warn!(
"ASP Command for session {}: application dropped reply channel",
session_id
);
}
} else {
tracing::warn!(
"ASP Command for session {}: session channel closed",
session_id
);
}
} else {
tracing::warn!(
"ASP Command mismatch: Session {} owned by {}.{}, req from {}.{}",
session_id,
sess.addr.network_number,
sess.addr.node_number,
req.source.network_number,
req.source.node_number
);
}
} else {
tracing::warn!("ASP Command: Session {} not found", session_id);
}
}
SPFunction::Tickle => {
// Tickle is ATP ALO — no reply is needed per the ASP spec.
// Just reset the session watchdog timer.
let session_id = header.session_id;
if let Some(sess) = sessions.get_mut(&session_id) {
sess.last_activity = tokio::time::Instant::now();
tracing::debug!(
"ASP Tickle received for session {}, watchdog reset",
session_id
);
} else {
tracing::warn!("ASP Tickle: Session {} not found", session_id);
}
}
_ => {
tracing::debug!("ASP Unimplemented function: {:?}", header.function);
}
}
}
} // end maybe_req arm
// ── 30-second tickle timer ───────────────────────────────────
_ = tickle_interval.tick() => {
let mut dead_sessions = Vec::new();
for (session_id, sess) in &sessions {
if sess.last_activity.elapsed() > std::time::Duration::from_secs(120) {
tracing::warn!("ASP Session {} timed out due to inactivity", session_id);
dead_sessions.push(*session_id);
continue;
}
tracing::debug!("ASP sending Tickle to session {}", session_id);
let user_bytes = [
SPFunction::Tickle as u8,
*session_id,
0,
0,
];
let _ = atp_req_clone.send_alo(sess.session_addr, user_bytes).await;
}
for session_id in dead_sessions {
sessions.remove(&session_id);
}
}
} // end select!
} // end loop
});
Ok(AspHandle { accept_tx })
}
}