release/src/router/dnsmasq/contrib/mactable/macscript

   1 #!/bin/bash
   2
   3 STATUS_FILE="/tmp/dnsmasq-ip-mac.status"
   4
   5 # Script for dnsmasq lease-change hook.
   6 # Maintains the above file with a IP address/MAC address pairs,
   7 # one lease per line. Works with IPv4 and IPv6 leases, file is
   8 # atomically updated, so no races for users of the data.
   9
  10 action="$1"
  11 mac="$2"   # IPv4
  12 ip="$3"
  13
  14 # ensure it always exists.
  15
  16 if [ ! -f "$STATUS_FILE" ]; then
  17   touch "$STATUS_FILE"
  18 fi
  19
  20 if [  -n "$DNSMASQ_IAID" ]; then
  21     mac="$DNSMASQ_MAC"   # IPv6
  22 fi
  23
  24 # worry about an add or old action when the MAC address is not known:
  25 # leave any old one in place in that case.
  26
  27 if [ "$action" = "add" -o "$action" = "old" -o "$action" = "del" ]; then
  28   if [ -n "$mac" -o "$action" = "del" ]; then
  29     sed "/^${ip//./\.} / d" "$STATUS_FILE" > "$STATUS_FILE".new
  30
  31     if [ "$action" = "add" -o "$action" = "old" ]; then
  32        echo "$ip $mac" >> "$STATUS_FILE".new
  33     fi
  34     mv  "$STATUS_FILE".new "$STATUS_FILE" # atomic update.
  35   fi
  36 fi