From 732fd1f771ed5a37268c89e5d5a72cbe4a62abab Mon Sep 17 00:00:00 2001
From: Michael Davidsaver <mdavidsaver@gmail.com>
Date: Mon, 4 Mar 2019 17:54:12 -0800
Subject: [PATCH] Troubleshoot "no more data in UDP packet"

---
 src/remote/blockingUDPTransport.cpp | 20 ++++++++++++++++----
 src/remote/pv/blockingUDP.h         |  5 +----
 2 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/src/remote/blockingUDPTransport.cpp b/src/remote/blockingUDPTransport.cpp
index f0fca62..cc4d070 100644
--- a/src/remote/blockingUDPTransport.cpp
+++ b/src/remote/blockingUDPTransport.cpp
@@ -9,6 +9,8 @@
 #include <ws2tcpip.h>
 #endif
 
+#include <sstream>
+
 #include <sys/types.h>
 #include <cstdio>
 
@@ -113,6 +115,16 @@ void BlockingUDPTransport::close() {
     close(true);
 }
 
+void BlockingUDPTransport::ensureData(std::size_t size) {
+    if (_receiveBuffer.getRemaining() >= size)
+        return;
+    std::ostringstream msg;
+    msg<<"no more data in UDP packet : "
+       <<_receiveBuffer.getPosition()<<":"<<_receiveBuffer.getLimit()
+       <<" for "<<size;
+    throw std::underflow_error(msg.str());
+}
+
 void BlockingUDPTransport::close(bool waitForThreadToComplete) {
     {
         Lock guard(_mutex);
@@ -256,12 +268,12 @@ void BlockingUDPTransport::run() {
                         processBuffer(thisTransport, fromAddress, &_receiveBuffer);
                     } catch(std::exception& e) {
                         LOG(logLevelError,
-                            "an exception caught while in UDP receiveThread at %s:%d: %s",
-                            __FILE__, __LINE__, e.what());
+                            "an exception caught while in UDP receiveThread %s at %s:%d: %s",
+                            _remoteName.c_str(), __FILE__, __LINE__, e.what());
                     } catch (...) {
                         LOG(logLevelError,
-                            "unknown exception caught while in UDP receiveThread at %s:%d.",
-                            __FILE__, __LINE__);
+                            "unknown exception caught while in UDP receiveThread %s at %s:%d.",
+                            _remoteName.c_str(), __FILE__, __LINE__);
                     }
                 }
             } else {
diff --git a/src/remote/pv/blockingUDP.h b/src/remote/pv/blockingUDP.h
index f1c560f..e7064a4 100644
--- a/src/remote/pv/blockingUDP.h
+++ b/src/remote/pv/blockingUDP.h
@@ -135,10 +135,7 @@ public:
 
     virtual void close() OVERRIDE FINAL;
 
-    virtual void ensureData(std::size_t size) OVERRIDE FINAL {
-        if (_receiveBuffer.getRemaining() < size)
-            throw std::underflow_error("no more data in UDP packet");
-    }
+    virtual void ensureData(std::size_t size) OVERRIDE FINAL;
 
     virtual void alignData(std::size_t alignment) OVERRIDE FINAL {
         _receiveBuffer.align(alignment);