From 2b9135b3125fe8bc4bd48d15ec40b68ec033f328 Mon Sep 17 00:00:00 2001
From: lidgren <lidgren@users.noreply.github.com>
Date: Fri, 10 Oct 2014 15:55:55 +0000
Subject: [PATCH] Don't try to parse packets identified as UPnP responses even
 when UPnP response parsing fails

---
 Lidgren.Network/NetPeer.Internal.cs | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/Lidgren.Network/NetPeer.Internal.cs b/Lidgren.Network/NetPeer.Internal.cs
index 35bd824..1b4f0ee 100644
--- a/Lidgren.Network/NetPeer.Internal.cs
+++ b/Lidgren.Network/NetPeer.Internal.cs
@@ -458,21 +458,27 @@ namespace Lidgren.Network
 
 				IPEndPoint ipsender = (IPEndPoint)m_senderRemote;
 
-				if (m_upnp != null && now < m_upnp.m_discoveryResponseDeadline)
+				if (m_upnp != null && now < m_upnp.m_discoveryResponseDeadline && bytesReceived > 32)
 				{
 					// is this an UPnP response?
-					try
+					string resp = System.Text.Encoding.ASCII.GetString(m_receiveBuffer, 0, bytesReceived);
+					if (resp.Contains("upnp:rootdevice") || resp.Contains("UPnP/1.0"))
 					{
-						string resp = System.Text.Encoding.ASCII.GetString(m_receiveBuffer, 0, bytesReceived);
-						if (resp.Contains("upnp:rootdevice") || resp.Contains("UPnP/1.0"))
+						try
 						{
 							resp = resp.Substring(resp.ToLower().IndexOf("location:") + 9);
 							resp = resp.Substring(0, resp.IndexOf("\r")).Trim();
 							m_upnp.ExtractServiceUrl(resp);
 							return;
 						}
+						catch (Exception ex)
+						{
+							LogDebug("Failed to parse UPnP response: " + ex.ToString());
+
+							// don't try to parse this packet further
+							return;
+						}
 					}
-					catch { }
 				}
 
 				NetConnection sender = null;