netconf: Ignore internal ifaces (e.g. DSA ports) in factory-config

On some system, certain interfaces are not usable by an end-user. The
canonical example of this is the ethernet MAC connected to a switch,
i.e. the DSA port.

Avoid having these be picked up in the generated factory-config, which
would be confusing to a user, by classifying them as "internal" ports
to be ignored by confd and friends.

board/common/rootfs/etc/iproute2/group

@@ -1,2 +1,3 @@
 1 port
 2 iface
+3 internal

board/common/rootfs/lib/infix/nameif

@@ -25,7 +25,7 @@ for netif in /sys/class/net/*; do
 
 	dsa="dsa$num"
 	logger -k -p user.notice -t "$ident" "Found DSA interface, renaming $iface -> $dsa"
-	ip link set dev "$iface" name $dsa
+	ip link set dev "$iface" name $dsa group internal
 	num=$((num + 1))
 done
 

board/netconf/rootfs/lib/infix/factory/gen-interfaces

@@ -18,6 +18,7 @@ EOF
 phys_ifaces=$(ip -d -j link show | jq -r '
 	 .[] |
 	 select(.link_type == "ether") |
+	 select(.group != "internal")  |
 	 select(has("linkinfo") | not) |
 	 .ifname')