add customization points

kamailio/default.cfg

@@ -327,6 +327,8 @@ route
     route(SIP_TRACE);
     #!endif
 
+    route_if_exists("CUSTOM_START_ROUTES");
+
     route(HANDLE_NOTIFY);
 
     #!ifdef AUTHORIZATION_ROLE
@@ -656,7 +658,7 @@ branch_route[MANAGE_BRANCH] {
     #!endif
 
     route(BRANCH_HEADERS);
-
+    route_if_exists("CUSTOM_BRANCH_HEADERS");
 }
 
 route[RELAY]
@@ -961,5 +963,6 @@ route[LOCAL_REQUEST]
     exit;
 }
 
+#!import_file "custom-routes.cfg"
 
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