SendQ bugfixes

Fix DoWrite running on errored sockets
Add testnet module for sendq and shutdown testing
Prevent DoWrite from trying to write when writes are blocking

git-svn-id: http://svn.inspircd.org/repository/trunk/inspircd@11768 e03df62e-2008-0410-955e-edbf42e46eb7

conf/modules.conf.example

@@ -1684,6 +1684,12 @@
 # To use, SWHOIS must be in one of your oper class blocks.
 #<module name="m_swhois.so">
 
+#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#
+# Test module: enable this to create a command useful in testing
+# flood control. To avoid accidental use on live networks, the server
+# name must contain ".test" to load the module
+#<module name="m_testnet.so">
+
 #-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#
 # Timed bans module: Adds timed channel bans and the /TBAN command
 #<module name="m_timedbans.so">

src/inspsocket.cpp

@@ -215,6 +215,11 @@ void StreamSocket::DoWrite()
 {
 	if (sendq.empty())
 		return;
+	if (!error.empty() || fd < 0 || fd == INT_MAX)
+	{
+		ServerInstance->Logs->Log("SOCKET", DEBUG, "DoWrite on errored or closed socket");
+		return;
+	}
 
 	if (IOHook)
 	{
@@ -272,11 +277,13 @@ void StreamSocket::DoWrite()
 	}
 	else
 	{
-		bool again = true;
-		while (again)
+		// don't even try if we are known to be blocking
+		if (GetEventMask() & FD_WRITE_WILL_BLOCK)
+			return;
+		// start out optimistic - we won't need to write any more
+		int eventChange = FD_WANT_EDGE_WRITE;
+		while (sendq_len && eventChange == FD_WANT_EDGE_WRITE)
 		{
-			again = false;
-
 			// Prepare a writev() call to write all buffers efficiently
 			int bufcount = sendq.size();
 		
@@ -284,14 +291,15 @@ void StreamSocket::DoWrite()
 			if (bufcount > IOV_MAX)
 			{
 				bufcount = IOV_MAX;
-				again = true;
 			}
 
+			int rv_max = 0;
 			iovec* iovecs = new iovec[bufcount];
 			for(int i=0; i < bufcount; i++)
 			{
 				iovecs[i].iov_base = const_cast<char*>(sendq[i].data());
 				iovecs[i].iov_len = sendq[i].length();
+				rv_max += sendq[i].length();
 			}
 			int rv = writev(fd, iovecs, bufcount);
 			delete[] iovecs;
@@ -310,7 +318,7 @@ void StreamSocket::DoWrite()
 				while (rv > 0 && !sendq.empty())
 				{
 					std::string& front = sendq.front();
-					if (front.length() < (size_t)rv)
+					if (front.length() <= (size_t)rv)
 					{
 						// this string got fully written out
 						rv -= front.length();
@@ -323,6 +331,11 @@ void StreamSocket::DoWrite()
 						rv = 0;
 					}
 				}
+				if (rv < rv_max)
+				{
+					// it's going to block now
+					eventChange = FD_WANT_FAST_WRITE | FD_WRITE_WILL_BLOCK;
+				}
 			}
 			else if (rv == 0)
 			{
@@ -330,11 +343,11 @@ void StreamSocket::DoWrite()
 			}
 			else if (errno == EAGAIN)
 			{
-				again = false;
+				eventChange = FD_WANT_FAST_WRITE | FD_WRITE_WILL_BLOCK;
 			}
 			else if (errno == EINTR)
 			{
-				again = true;
+				// restart interrupted syscall
 			}
 			else
 			{
@@ -346,15 +359,9 @@ void StreamSocket::DoWrite()
 			// error - kill all events
 			ServerInstance->SE->ChangeEventMask(this, FD_WANT_NO_READ | FD_WANT_NO_WRITE);
 		}
-		else if (sendq_len)
-		{
-			// writes have blocked, we can use FAST_WRITE to find when they unblock
-			ServerInstance->SE->ChangeEventMask(this, FD_WANT_FAST_WRITE | FD_WRITE_WILL_BLOCK);
-		}
 		else
 		{
-			// writes are done, we can use EDGE_WRITE to stop asking for write
-			ServerInstance->SE->ChangeEventMask(this, FD_WANT_EDGE_WRITE);
+			ServerInstance->SE->ChangeEventMask(this, eventChange);
 		}
 	}
 }

src/modules/m_testnet.cpp

@@ -0,0 +1,66 @@
+/*       +------------------------------------+
+ *       | Inspire Internet Relay Chat Daemon |
+ *       +------------------------------------+
+ *
+ *  InspIRCd: (C) 2002-2009 InspIRCd Development Team
+ * See: http://wiki.inspircd.org/Credits
+ *
+ * This program is free but copyrighted software; see
+ *	    the file COPYING for details.
+ *
+ * ---------------------------------------------------
+ */
+
+/* $ModDesc: Provides a module for testing the server while linked in a network */
+
+#include "inspircd.h"
+
+class CommandTest : public Command
+{
+ public:
+	CommandTest(Module* parent) : Command(parent, "TEST", 1)
+	{
+		syntax = "<action> <parameters>";
+	}
+
+	CmdResult Handle(const std::vector<std::string> &parameters, User *user)
+	{
+		if (parameters[0] == "flood")
+		{
+			unsigned int count = parameters.size() > 1 ? atoi(parameters[1].c_str()) : 100;
+			std::string line = parameters.size() > 2 ? parameters[2] : ":z.z NOTICE !flood :Flood text";
+			for(unsigned int i=0; i < count; i++)
+				user->Write(line);
+		}
+		else if (parameters[0] == "freeze")
+		{
+			user->Penalty += 100;
+		}
+		else if (parameters[0] == "shutdown")
+		{
+			int i = parameters.size() > 1 ? atoi(parameters[1].c_str()) : 2;
+			ServerInstance->SE->Shutdown(user->GetFd(), i);
+		}
+		return CMD_SUCCESS;
+	}
+};
+
+class ModuleTest : public Module
+{
+	CommandTest cmd;
+ public:
+	ModuleTest() : cmd(this)
+	{
+		if (!strstr(ServerInstance->Config->ServerName, ".test"))
+			throw ModuleException("Don't load modules without reading their descriptions!");
+		ServerInstance->AddCommand(&cmd);
+	}
+
+	Version GetVersion()
+	{
+		return Version("Provides a module for testing the server while linked in a network", VF_VENDOR|VF_OPTCOMMON);
+	}
+};
+
+MODULE_INIT(ModuleTest)
+

src/users.cpp

@@ -575,13 +575,12 @@ void User::AddWriteBuf(const std::string &data)
 	if (!quitting && MyClass && getSendQSize() + data.length() > MyClass->GetSendqHardMax() && !HasPrivPermission("users/flood/increased-buffers"))
 	{
 		/*
-		 * Fix by brain - Set the error text BEFORE calling, because
-		 * if we dont it'll recursively  call here over and over again trying
-		 * to repeatedly add the text to the sendq!
+		 * Quit the user FIRST, because otherwise we could recurse
+		 * here and hit the same limit.
 		 */
 		ServerInstance->Users->QuitUser(this, "SendQ exceeded");
-		ServerInstance->SNO->WriteToSnoMask('a', "User %s SendQ of %lu exceeds connect class maximum of %lu",
-			nick.c_str(), (unsigned long)getSendQSize() + data.length(), MyClass->GetSendqHardMax());
+		ServerInstance->SNO->WriteToSnoMask('a', "User %s SendQ exceeds connect class maximum of %lu",
+			nick.c_str(), MyClass->GetSendqHardMax());
 		return;
 	}