From 27eb5b251e39dbbf526c3bf8d05ce36b5275972b Mon Sep 17 00:00:00 2001
From: Luke Granger-Brown <hg@lukegb.com>
Date: Wed, 17 Aug 2022 02:30:09 +0100
Subject: [PATCH] blade-router: tweak export filter to drop local communities

---
 ops/nixos/lib/bgp.nix          | 16 ++++++++++++++--
 ops/nixos/lib/blade-router.nix |  8 ++++----
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/ops/nixos/lib/bgp.nix b/ops/nixos/lib/bgp.nix
index f2baa8a3f7..4086f96c2f 100644
--- a/ops/nixos/lib/bgp.nix
+++ b/ops/nixos/lib/bgp.nix
@@ -30,6 +30,18 @@ let
       bgp_local_pref = ${toString ix.remote.bgp_local_pref};
       accept;
     }
+    filter bgp_export_${ixName}4
+    {
+      if ! ((ro, ${toString ix.local.asn}, 1000) ~ bgp_ext_community) then reject;
+      bgp_ext_community.delete([(ro, ${toString ix.local.asn}, *)]);
+      accept;
+    }
+    filter bgp_export_${ixName}6
+    {
+      if ! ((ro, ${toString ix.local.asn}, 1000) ~ bgp_ext_community) then reject;
+      bgp_ext_community.delete([(ro, ${toString ix.local.asn}, *)]);
+      accept;
+    }
     protocol pipe ${ixName}pipe_4 {
       table ${ixName}4;
       peer table master4;
@@ -61,7 +73,7 @@ let
       ipv4 {
         table ${ixName}4;
         import all;
-        export ${if ix.remote.is_route_collector then "all" else "where ((ro, ${toString ix.local.asn}, 1000) ~ bgp_ext_community)"};
+        export ${if ix.remote.is_route_collector then "all" else "filter bgp_export_${ixName}4"};
         ${prefixLimitSnippet ix.remote.prefix_limit.v4}
       };
     };
@@ -77,7 +89,7 @@ let
       ipv6 {
         table ${ixName}6;
         import all;
-        export ${if ix.remote.is_route_collector then "all" else "where ((ro, ${toString ix.local.asn}, 1000) ~ bgp_ext_community)"};
+        export ${if ix.remote.is_route_collector then "all" else "filter bgp_export_${ixName}6"};
         ${prefixLimitSnippet ix.remote.prefix_limit.v6}
       };
     };
diff --git a/ops/nixos/lib/blade-router.nix b/ops/nixos/lib/blade-router.nix
index 7e431f9397..6534109cc2 100644
--- a/ops/nixos/lib/blade-router.nix
+++ b/ops/nixos/lib/blade-router.nix
@@ -349,10 +349,10 @@ in
               v4 = "195.66.225.6";
               v6 = "2001:7f8:4::3f94:2";
             }];
-          }];
-          bgp_local_pref = 120;
-          prefix_limit.v4 = 1000;
-          prefix_limit.v6 = 200;
+            bgp_local_pref = 120;
+            prefix_limit.v4 = 1000;
+            prefix_limit.v6 = 200;
+          };
         };
         export.v4 = [ "92.118.28.0/24" ];
         export.v6 = [ "2a09:a441::/32" ];