modules/m_silence: Allow U-lined services to bypass silence masks

Adds a config entry (silence->exemptuline) that specifies whether
users on U-lined servers can bypass silence masks.

docs/conf/modules.conf.example

@@ -1841,7 +1841,10 @@
 #<module name="m_silence.so">
 #
 # Set the maximum number of entries allowed on a user's silence list.
-#<silence maxentries="32">
+#<silence maxentries="32"
+#
+# Whether messages from U-lined servers will bypass silence masks.
+#exemptuline="yes">
 
 #-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#-#
 # SQLite3 module: Allows other SQL modules to access SQLite3          #

src/modules/m_silence.cpp

@@ -291,6 +291,7 @@ class CommandSilence : public Command
 class ModuleSilence : public Module
 {
 	unsigned int maxsilence;
+	bool ExemptULine;
 	CommandSilence cmdsilence;
 	CommandSVSSilence cmdsvssilence;
  public:
@@ -302,9 +303,13 @@ class ModuleSilence : public Module
 
 	void ReadConfig(ConfigStatus& status) CXX11_OVERRIDE
 	{
-		maxsilence = ServerInstance->Config->ConfValue("silence")->getInt("maxentries", 32);
+		ConfigTag* tag = ServerInstance->Config->ConfValue("silence");
+
+		maxsilence = tag->getInt("maxentries", 32);
 		if (!maxsilence)
 			maxsilence = 32;
+
+		ExemptULine = tag->getBool("exemptuline", true);
 	}
 
 	void On005Numeric(std::map<std::string, std::string>& tokens) CXX11_OVERRIDE
@@ -351,6 +356,9 @@ class ModuleSilence : public Module
 
 	ModResult MatchPattern(User* dest, User* source, int pattern)
 	{
+		if (ExemptULine && source->server->IsULine())
+			return MOD_RES_PASSTHRU;
+
 		silencelist* sl = cmdsilence.ext.get(dest);
 		if (sl)
 		{