Update bird/bird.conf.tmpl

bird/bird.conf.tmpl

@@ -1,26 +1,61 @@
+# Lixonet BIRD configuration
+# This is a templated file that automatically generates values at configuration time
+# If you edit this file, it will be overwritten. Changes to the general structure of
+# this configuration file that should be persisted should be committed to Git.
+# For BIRD 2.0 configuration reference, see:
+#   https://bird.network.cz/?get_doc&f=bird.html&v=20
+
+
+# Global variables
+# https://bird.network.cz/?get_doc&v=20&f=bird-3.html#ss3.2
+
 log stderr all;         # Using docker; defer logging to stderr
 debug protocols all;    # Enable debugging
-
 router id ${address};
 
+# Device
+# See: https://bird.network.cz/?get_doc&v=20&f=bird-6.html#ss6.4
+# This controls which interfaces BGP, etc. will bind to for communication
+# This prevents BGP from listening on eth0/off-network
+protocol device {
+    scan time 10;       # Scan the interfaces often
+    interface "lixonet" {
+        preferred ${address};
+    };
+};
+
+# Direct (unnecessary for Lixonet)
+# See: https://bird.network.cz/?get_doc&v=20&f=bird-6.html#ss6.5
 # Disable automatically generating direct routes to all network interfaces.
 protocol direct {
     disabled;               # Disable by default
 };
 
-protocol device {
+# Kernel routing table
+# See: https://bird.network.cz/?get_doc&v=20&f=bird.html#toc6.6
+protocol kernel {               # Primary routing table
+    learn;                  # Learn alien routes from the kernel
+    persist;                # Don't remove routes on bird shutdown
+    scan time 10;           # Scan kernel routing table every 10 seconds
+    ipv4 {
+        import none;        # Don't try to import any routes from the kernel
+        export all;         # Export everything we are told to the kernel
     };
+}
 
+# BGP (primary Lixonet routing protocol)
 # Define a template to use when connecting to other BGP clients on the EE network
 template bgp lixonet_client {
-    local as ${asn};
+    local as ${asn};                # Local AS advertised to peers, read from lixonet.conf.
     source address ${address};      # What local address we use for the TCP connection
     path metric 1;		            # Prefer routes with shorter paths (like Cisco does)
-    next hop self;
 
-# TODO: Syntax error?
+    # Always advertise our own local address as a next hop, even in cases where the
-#   aigp originate;
+    # current Next Hop attribute should be used unchanged.
+    # Reason: tinc NEEDS this, otherwise Layer3 inter-routing on the mesh will be broken
+    next hop self ebgp;
 
+    aigp originate;
 };
 
 # Neighbors