Add: complete the filter of internal network and downstream

lib/20-community-downstream.conf

@@ -0,0 +1,14 @@
+function downstream_import_filter(int ASN) {
+    if !is_valid() then return false;
+    if bgp_path.last !~ DOWNSTREAM_ASN then return false;
+    pub_add_communities(ASN, 20);
+    pub_preprocess_communities();
+    return true;
+}
+
+function downstream_export_filter(int ASN) {
+    if !is_valid() then return false;
+    bgp_path.delete([4200000000..4225479999]);
+    if pub_process_communities(ASN, 20) then return true;
+    else return false;
+}