Reject unexpected incoming data.

YSFReflector/YSFReflector.cpp

@@ -71,6 +71,7 @@ void CYSFReflector::run()
 
 	CTimer watchdogTimer(1000U, 0U, 1500U);
 
+	unsigned char tag[YSF_CALLSIGN_LENGTH];
 	unsigned char src[YSF_CALLSIGN_LENGTH];
 	unsigned char dst[YSF_CALLSIGN_LENGTH];
 
@@ -80,6 +81,8 @@ void CYSFReflector::run()
 		unsigned int len = network.readData(buffer);
 		if (len > 0U) {
 			if (!watchdogTimer.isRunning()) {
+				::memcpy(tag, buffer + 4U, YSF_CALLSIGN_LENGTH);
+
 				if (::memcmp(buffer + 14U, "          ", YSF_CALLSIGN_LENGTH) != 0)
 					::memcpy(src, buffer + 14U, YSF_CALLSIGN_LENGTH);
 				else
@@ -91,8 +94,8 @@ void CYSFReflector::run()
 					::memcpy(dst, "??????????", YSF_CALLSIGN_LENGTH);
 
 				::fprintf(stdout, "Received data from %10.10s to %10.10s at %10.10s\n", src, dst, buffer + 4U);
-			}
+			} else {
-			else {
+				if (::memcmp(tag, buffer + 4U, YSF_CALLSIGN_LENGTH) == 0) {
 					bool changed = false;
 
 					if (::memcmp(buffer + 14U, "          ", YSF_CALLSIGN_LENGTH) != 0 && ::memcmp(src, "??????????", YSF_CALLSIGN_LENGTH) == 0) {
@@ -108,7 +111,10 @@ void CYSFReflector::run()
 					if (changed)
 						::fprintf(stdout, "Received data from %10.10s to %10.10s at %10.10s\n", src, dst, buffer + 4U);
 				}
+			}
 
+			// Only accept transmission from an already accepted repeater
+			if (::memcmp(tag, buffer + 4U, YSF_CALLSIGN_LENGTH) == 0) {
 				watchdogTimer.start();
 
 				std::string callsign = std::string((char*)(buffer + 4U), YSF_CALLSIGN_LENGTH);
@@ -125,6 +131,7 @@ void CYSFReflector::run()
 					watchdogTimer.stop();
 				}
 			}
+		}
 
 		// Refresh/add repeaters based on their polls
 		std::string callsign;