fix(network): don't use same ifname multiple times

If multiple ibft interfaces exist, set_ifname() may reuse the same
name (usually "ibft0"), because it's usually called cmdline time,
when no interfaces exist in sysfs yet. Remember the number used
set and don't use it again.

Author: mwilck

modules.d/40network/net-lib.sh

@@ -222,6 +222,7 @@ set_ifname() {
     for n in $(getargs ifname=); do
         strstr "$n" "$mac" && echo "${n%%:*}" && return
     done
+    [ ! -f "/tmp/set_ifname_$name" ] || read -r num < "/tmp/set_ifname_$name"
     # otherwise, pick a new name and use that
     while :; do
         num=$((num + 1))
@@ -232,6 +233,7 @@ set_ifname() {
         break
     done
     echo "ifname=$name$num:$mac" >> /etc/cmdline.d/45-ifname.conf
+    echo "$num" > "/tmp/set_ifname_$name"
     echo "$name$num"
 }