freifunk: implement new gateway selection

hosts/freifunk/default.nix

@@ -14,6 +14,7 @@ let
   rt_table_hosts = 7;
   rt_table_nets = rt_table_hosts + 1;
   rt_table_tuns = rt_table_hosts + 2;
+  rt_table_ffgw = 244;
   sysinfo-json = import ./sysinfo-json.nix { inherit pkgs ddmeshNode; };
 
   upstreams = [ "upstream4" "upstream3" ];
@@ -26,6 +27,29 @@ let
     core = "00:de:13:cb:9a:7b";
     bmx = "00:de:13:cb:9a:7c";
   };
+  bmxdGatewayScript = with pkgs; writeScript "bmxd-gateway.sh" ''
+    #! ${runtimeShell} -e
+
+    echo "bmxd-gateway.sh: $@" >&2
+
+    PATH=${lib.makeBinPath [ iproute2 ]}
+    case "$1" in
+      gateway)
+        ;;
+      del|init)
+        ;;
+      *)
+        ip tunnel del ffgw || true
+
+        ip tunnel add ffgw mode ipip local 10.200.${ddmeshAddrPart} remote "$1"
+        ip link set ffgw up
+        ip addr add 10.200.${ddmeshAddrPart}/32 dev ffgw
+        ip route add 0/0 dev ffgw table ${toString rt_table_ffgw}
+        ip rule add pref 33500 table ${toString rt_table_ffgw} || true
+        ;;
+    esac
+  '';
+
 in {
   imports = [
     "${modulesPath}/profiles/minimal.nix"
@@ -234,8 +258,6 @@ in {
             FirewallMark = upstreamMark;
           };
         } ];
-        # reverse dependency
-        networkConfig.Tunnel = [ "wg-vpn6" ];
       };
     };
   };
@@ -250,13 +272,20 @@ in {
           --no_fork 1 \
           --throw-rules 0 \
           --prio-rules 0 \
-          --gateway_tunnel_network 10.200.0.0/16 \
-          --purge_timeout 20 \
-          --one_way_tunnel 1 \
+          --network 10.200.0.0/16 \
+          --netid 0 \
+          --only_community_gw 1 \
+          --script ${bmxdGatewayScript} \
+          --hop_penalty 1 \
+          --lateness_penalty 10 \
+          --ogm_broadcasts 100 \
+          --udp_data_size 512 \
+          --ogm_interval 5000 \
+          --purge_timeout 35 \
           -r 3 --gateway_hysteresis 20 \
-          dev=${meshLoopback} /linklayer 0 \
-          dev=${meshInterface} /linklayer 1 \
-          dev=ipip-node51001 /linklayer 1
+          --dev ${meshLoopback} /linklayer 0 \
+          --dev ${meshInterface} /linklayer 1 \
+          --dev ipip-node51001 /linklayer 1
       '';
       Restart = "always";
       RestartSec = "60";