SL-16637 Better validation of data in LLEstablishAgentCommunication

Do not set capability when disconnected, it creates new coroutines that will do nothing and region might be invalid resulting in a crash. Do not initilize LLWorld.

indra/newview/llworld.cpp

@@ -1195,6 +1195,16 @@ class LLEstablishAgentCommunication : public LLHTTPNode
 	virtual void post(ResponsePtr response, const LLSD& context, const LLSD& input) const
 	{
         if (LLApp::isExiting())
+        {
+            return;
+        }
+
+        if (gDisconnected)
+        {
+            return;
+        }
+
+        if (!LLWorld::instanceExists())
         {
             return;
         }
@@ -1208,6 +1218,11 @@ class LLEstablishAgentCommunication : public LLHTTPNode
 		}
 
         LLHost sim(input["body"]["sim-ip-and-port"].asString());
+        if (sim.isInvalid())
+        {
+            LL_WARNS() << "Got EstablishAgentCommunication with invalid host" << LL_ENDL;
+            return;
+        }
 
 		LLViewerRegion* regionp = LLWorld::getInstance()->getRegion(sim);
 		if (!regionp)
@@ -1217,7 +1232,7 @@ class LLEstablishAgentCommunication : public LLHTTPNode
 			return;
 		}
 		LL_DEBUGS("CrossingCaps") << "Calling setSeedCapability from LLEstablishAgentCommunication::post. Seed cap == "
-				<< input["body"]["seed-capability"] << LL_ENDL;
+				<< input["body"]["seed-capability"] << " for region " << regionp->getRegionID() << LL_ENDL;
 		regionp->setSeedCapability(input["body"]["seed-capability"]);
 	}
 };