set-wifi-mac.sh

#!/bin/sh

# Changes WiFi NIC MAC address to MD5-based semi-random value

name="$1"
iface="$2"

: "${ifaces:=$(for i in /sys/class/net/*;do test ! -d $i/wireless || { echo -n "$_s${i##*/}";_s=" ";};done)}"
: "${iface:=$(echo "$ifaces" | cut -f1 -d" ")}"

test -n "$iface" || {
  echo "ERROR: cannot find interface" >&2
  test -z "$name" || exit 1
}

test -n "$name" || {
  echo "Usage: ${0##*/} <name> [<iface=$iface>]" >&2
  echo "Available interaces: $ifaces" >&2
  exit 1
}

name2mac() {
  local name="$1" new_mac octet
  for octet in $(echo -n "$name" | md5sum | fold -w2 | head -6);do
    if test -z "$new_mac";then
      new_mac="$(printf "%02x" $((0x$octet&0xfe|2)))"
    else
      new_mac="$new_mac:$octet"
    fi
  done
  echo "$new_mac"
}

new_mac="$(name2mac "$name")"

set -xe
ip link set "$iface" address "$new_mac"