Add more arguments for the 'udp' check command

fixes #8410

doc/7-icinga-template-library.md

@@ -718,6 +718,9 @@ Name            | Description
 ----------------|--------------
 udp_address     | **Optional.** The host's address. Defaults to "$address$" or "$address6$" if the `address` attribute is not set.
 udp_port        | **Required.** The port that should be checked.
+udp_send        | **Required.** The payload to send in the UDP datagram.
+udp_expect      | **Required.** The payload to expect in the response datagram.
+udp_quit        | **Optional.** The payload to send to 'close' the session.
 
 
 ### <a id="plugin-check-command-ups"></a> ups

itl/command-plugins.conf

@@ -198,6 +198,18 @@ object CheckCommand "udp" {
 		"-p", "$udp_port$"
 	]
 
+	arguments = {
+		"-s" = {
+			value = "$udp_send$"
+			required = true
+		}
+		"-e" = {
+			value = "$udp_expect$"
+			required = true
+		}
+		"-q" = "$udp_quit$"
+	}
+
 	vars.udp_address = "$check_address$"
 }