Allow Linux optimizations (UDP GRO for forwarding) on multiple defaul…

…t interfaces and IPv6 (hassio-addons#361)

tailscale/rootfs/etc/s6-overlay/s6-rc.d/post-tailscaled/run

@@ -4,7 +4,7 @@
 # Home Assistant Community Add-on: Tailscale
 # Runs after the machine has been logged in into the Tailscale network
 # ==============================================================================
-declare default_route_device
+declare interface
 declare -a options
 declare -a routes=()
 declare route
@@ -15,12 +15,16 @@ declare keyexpiry
 
 # Linux optimizations for subnet routers and exit nodes
 # Based on: https://tailscale.com/kb/1320/performance-best-practices#linux-optimizations-for-subnet-routers-and-exit-nodes
-# Note: Changes made via ethtool are not persistent and will be lost after the machine shuts down.
+# Note: Changes made via ethtool are not persistent and will be lost after the machine shuts down
 # Note: Executing it before "tailscale up" to avoid warning messages
-default_route_device=$(ip -4 route show 0/0 | cut -f5 -d' ')
-if bashio::var.has_value "${default_route_device}"; then
-  ethtool -K "${default_route_device}" rx-udp-gro-forwarding on rx-gro-list off
-fi
+for interface in $( \
+  { ip -4 route show 0/0; ip -6 route show ::/0; } \
+  | cut -f5 -d' ' \
+  | sort -u)
+do
+  bashio::log.info "Allow UDP GRO for forwarding on ${interface}"
+  ethtool -K "${interface}" rx-udp-gro-forwarding on rx-gro-list off
+done
 
 # Default options
 options+=(--hostname "$(bashio::info.hostname)")