Add asterisk

It seems to work - I connected a client to it - but I never successfully
made any calls.

modules/system/asterisk.nix

@@ -0,0 +1,97 @@
+{ pkgs, lib, config, ... }:
+with lib;
+{
+	options.myModules.asterisk.enable = mkEnableOption "custom asterisk configuration";
+
+	config = mkIf config.myModules.asterisk.enable {
+		networking.firewall = {
+			allowedTCPPorts = [ 5060 ];
+			allowedUDPPortRanges = [
+				{ from=1000; to=20000; }
+			];
+			allowedUDPPorts = [ 4569 5060 ];
+		};
+		services.asterisk = {
+			enable = true;
+			confFiles = {
+				"extensions.conf" = ''
+[from-internal]
+; dial the lecture rooms & backoffice
+; the syntax is NUMBER,SEQUENCE,FUNCTION
+; to call someone do Dial(MODULE/account, timeout)
+exten => 1001,1,Dial(PJSIP/saal1,20)
+exten => 1002,1,Dial(PJSIP/saal2,20)
+exten => 1600,1,Dial(PJSIP/backoffice,20)
+
+; Dial 100 for "hello, world"
+; this is useful when configuring/debugging clients (snoms)
+exten => 100,1,Answer()
+same  =>     n,Wait(1)
+same  =>     n,Playback(hello-world)
+same  =>     n,Hangup()
+; note: "n" is a keyword meaning "the last line's value, plus 1"
+; "same" is a keyword referring to the last-defined extension
+'';
+				"pjsip.conf" = ''
+; we use UDP for transport
+[transport-udp]
+type=transport
+protocol=udp
+bind=0.0.0.0
+
+; Note: this defines a macro, to shorten the config further down
+[endpoint_internal](!)
+type=endpoint
+context=from-internal
+disallow=all
+allow=ulaw
+
+[auth_userpass](!)
+type=auth
+auth_type=userpass
+
+[aor_dynamic](!)
+type=aor
+max_contacts=1
+
+
+; here come the definitions for our phones, using the macros from above
+
+; lecture hall 1
+[saal1](endpoint_internal)
+auth=saal1
+aors=saal1
+[saal1](auth_userpass)
+; well, maybe set a better password than this
+password=saal1
+username=saal1
+[saal1](aor_dynamic)
+
+; lecture hall 2
+[saal2](endpoint_internal)
+auth=saal2
+aors=saal2
+[saal2](auth_userpass)
+password=saal2
+username=saal2
+[saal2](aor_dynamic)
+
+[backoffice](endpoint_internal)
+auth=backoffice
+aors=backoffice
+[backoffice](auth_userpass)
+password=backoffice
+username=backoffice
+[backoffice](aor_dynamic)
+'';
+				"logger.conf" = ''
+[general]
+
+[logfiles]
+; Add debug output to log
+syslog.local0 => notice,warning,error,debug
+'';
+			};
+		};
+	};
+}

modules/system/default.nix

@@ -1,5 +1,6 @@
 {
 	imports = [
+		./asterisk.nix
 		./authentik.nix
 		./authentik-backup.nix
 		./base.nix