From 071cd14477648237766bd9eef069669e87214147 Mon Sep 17 00:00:00 2001
From: Michael Woods <alienhunter3@gmail.com>
Date: Sun, 16 Feb 2025 11:11:53 -0500
Subject: [PATCH] Added some connection client locks to make sure that nothing
 interrupts a connection send/receive routine.

---
 src/packetserver/client/__init__.py | 39 ++++++++++++++++++-----------
 1 file changed, 25 insertions(+), 14 deletions(-)

diff --git a/src/packetserver/client/__init__.py b/src/packetserver/client/__init__.py
index dbd6cd9..f5bfb29 100644
--- a/src/packetserver/client/__init__.py
+++ b/src/packetserver/client/__init__.py
@@ -7,6 +7,7 @@ import ax25
 import logging
 import signal
 import time
+from threading import Lock
 from msgpack.exceptions import OutOfData
 from typing import Callable, Self, Union, Optional
 from traceback import  format_exc
@@ -23,6 +24,8 @@ class Client:
         self.callsign = client_callsign
         self.app = pe.app.Application()
         self.started = False
+        self._connection_locks = {}
+        self.lock_locker = Lock()
         signal.signal(signal.SIGINT, self.exit_gracefully)
         signal.signal(signal.SIGTERM, self.exit_gracefully)
 
@@ -85,6 +88,9 @@ class Client:
             raise RuntimeError("Must start client before creating connections.")
         if not ax25.Address.valid_call(dest):
             raise ValueError(f"Provided destination callsign '{dest}' is invalid.")
+        with self.lock_locker:
+            if dest.upper() not in self._connection_locks:
+                self._connection_locks[dest.upper()] = Lock()
         conn = self.connection_callsign(dest.upper())
         if conn is not None:
             return conn
@@ -103,20 +109,25 @@ class Client:
         if conn.state.name != "CONNECTED":
             raise RuntimeError("Connection is not connected.")
         logging.debug(f"Sending request {req}")
-        conn.send_data(req.pack())
-        cutoff_date = datetime.datetime.now() + datetime.timedelta(seconds=timeout)
-        while datetime.datetime.now() < cutoff_date:
-            if conn.state.name != "CONNECTED":
-                logging.error(f"Connection {conn} disconnected.")
-                return None
-            try:
-                unpacked = conn.data.unpack()
-            except:
-                time.sleep(.1)
-                continue
-            msg = Message.partial_unpack(unpacked)
-            return Response(msg)
-        return None
+        dest = conn.remote_callsign.upper()
+        with self.lock_locker:
+            if dest not in self._connection_locks:
+                self._connection_locks[dest] = Lock()
+        with self._connection_locks[dest]:
+            conn.send_data(req.pack())
+            cutoff_date = datetime.datetime.now() + datetime.timedelta(seconds=timeout)
+            while datetime.datetime.now() < cutoff_date:
+                if conn.state.name != "CONNECTED":
+                    logging.error(f"Connection {conn} disconnected.")
+                    return None
+                try:
+                    unpacked = conn.data.unpack()
+                except:
+                    time.sleep(.1)
+                    continue
+                msg = Message.partial_unpack(unpacked)
+                return Response(msg)
+            return None
 
     def send_receive_callsign(self, req: Request, callsign: str, timeout: int = 300) -> Optional[Response]:
         return self.send_and_receive(req, self.connection_for(callsign), timeout=timeout)