MAVLinkInterface.cs: remove 0.9 from mavlink parser

treating 'U' as a header marker byte leads to the problem that we will accidentally consume parts of a valid packet after receiving a "plain text" message. This is particularly problematic in ArduPilot's config-error-loop, as we emit the problem as both statustext and raw "line noise" to the GCS; the statustext is lost, mneaning the user doesn't get any specific error message from the autopilot, just "in config error loop". Co-authored-by: Bob Long <[email protected]> Co-authored-by: Michelle Rossouw <[email protected]>
ArduPilot · Feb 3, 2025 · 06378f1 · 06378f1
1 parent b2c5347
commit 06378f1
Showing 1 changed file with 5 additions and 5 deletions.
diff --git a/ExtLibs/ArduPilot/Mavlink/MAVLinkInterface.cs b/ExtLibs/ArduPilot/Mavlink/MAVLinkInterface.cs
@@ -4745,7 +4745,7 @@ public async Task<MAVLinkMessage> readPacketAsync()
                     }
 
                     // check if looks like a mavlink packet and check for exclusions and write to console
-                    if (buffer[0] != MAVLINK_STX_MAVLINK1 && buffer[0] != 'U' && buffer[0] != MAVLINK_STX)
+                    if (buffer[0] != MAVLINK_STX_MAVLINK1 && buffer[0] != MAVLINK_STX)
                     {
                         if (buffer[0] >= 0x20 && buffer[0] <= 127 || buffer[0] == '\n' || buffer[0] == '\r')
                         {
@@ -4787,7 +4787,7 @@ public async Task<MAVLinkMessage> readPacketAsync()
                         Console.WriteLine(DateTime.Now.Millisecond + " SR2 " + BaseStream?.BytesToRead);
 
                     // check for a header
-                    if (buffer[0] == MAVLINK_STX_MAVLINK1 || buffer[0] == MAVLINK_STX || buffer[0] == 'U')
+                    if (buffer[0] == MAVLINK_STX_MAVLINK1 || buffer[0] == MAVLINK_STX)
                     {
                         var mavlinkv2 = buffer[0] == MAVLINK_STX ? true : false;
 
@@ -5097,7 +5097,7 @@ public async Task<MAVLinkMessage> readPacketAsync()
                 packetSeemValid = false;
                 //The following IF had to be splitted to accomodate the new place of Readlock end.
                 //packetSeemValid helps it.
-                if ((message.header == 'U' || message.header == MAVLINK_STX_MAVLINK1 ||
+                if ((message.header == MAVLINK_STX_MAVLINK1 ||
                      message.header == MAVLINK_STX) &&
                     buffer.Length >= message.payloadlength)
                 {
@@ -6563,15 +6563,15 @@ private MAVLinkMessage readlogPacketMavlink()
                 {
                     case 0:
                         byte0 = tempb;
-                        if (byte0 != 'U' && byte0 != MAVLINK_STX_MAVLINK1 && byte0 != MAVLINK_STX)
+                        if (byte0 != MAVLINK_STX_MAVLINK1 && byte0 != MAVLINK_STX)
                         {
                             log.DebugFormat("logread - lost sync byte {0} pos {1}", byte0,
                                 logplaybackfile.BaseStream.Position);
                             // seek to next valid
                             do
                             {
                                 byte0 = logplaybackfile.ReadByte();
-                            } while (byte0 != 'U' && byte0 != MAVLINK_STX_MAVLINK1 && byte0 != MAVLINK_STX);
+                            } while (byte0 != MAVLINK_STX_MAVLINK1 && byte0 != MAVLINK_STX);
 
                             a = 1;
                             continue;