Quick fix for a missing variable

[loctrkd.git] / gps303 / collector.py

diff --git a/gps303/collector.py b/gps303/collector.py
index de65394d4f4b5eefb0527bea384746cea5d5b2a0..0efc669fd908e83a480c3e86839efda8b2254d45 100644 (file)
--- a/gps303/collector.py
+++ b/gps303/collector.py
@@ -38,7 +38,7 @@ class Client:
         """Read from the socket and parse complete messages"""
         try:
             segment = self.sock.recv(4096)
-        except OSError:
+        except OSError as e:
             log.warning(
                 "Reading from fd %d (IMEI %s): %s",
                 self.sock.fileno(),
@@ -69,7 +69,20 @@ class Client:
                 )
                 self.buffer = self.buffer[framestart:]
             # At this point, buffer starts with a packet
-            frameend = self.buffer.find(b"\r\n", 4)
+            if len(self.buffer) < 6:  # no len and proto - cannot proceed
+                break
+            exp_end = self.buffer[2] + 3  # Expect '\r\n' here
+            frameend = 0
+            # Length field can legitimeely be much less than the
+            # length of the packet (e.g. WiFi positioning), but
+            # it _should not_ be greater. Still sometimes it is.
+            # Luckily, not by too much: by maybe two or three bytes?
+            # Do this embarrassing hack to avoid accidental match
+            # of some binary data in the packet against '\r\n'.
+            while True:
+                frameend = self.buffer.find(b"\r\n", frameend)
+                if frameend >= (exp_end - 3):  # Found realistic match
+                    break
             if frameend == -1:  # Incomplete frame, return what we have
                 break
             packet = self.buffer[2:frameend]
@@ -176,9 +189,7 @@ def runserver(conf):
                 elif fl & zmq.POLLIN:
                     received = clients.recv(sk)
                     if received is None:
-                        log.debug(
-                            "Terminal gone from fd %d (IMEI %s)", sk, imei
-                        )
+                        log.debug("Terminal gone from fd %d", sk)
                         tostop.append(sk)
                     else:
                         for imei, when, peeraddr, packet in received: