| #!/bin/bash |
| |
| STATUS_FILE="/tmp/dnsmasq-ip-mac.status" |
| |
| # Script for dnsmasq lease-change hook. |
| # Maintains the above file with a IP address/MAC address pairs, |
| # one lease per line. Works with IPv4 and IPv6 leases, file is |
| # atomically updated, so no races for users of the data. |
| |
| action="$1" |
| mac="$2" # IPv4 |
| ip="$3" |
| |
| # ensure it always exists. |
| |
| if [ ! -f "$STATUS_FILE" ]; then |
| touch "$STATUS_FILE" |
| fi |
| |
| if [ -n "$DNSMASQ_IAID" ]; then |
| mac="$DNSMASQ_MAC" # IPv6 |
| fi |
| |
| # worry about an add or old action when the MAC address is not known: |
| # leave any old one in place in that case. |
| |
| if [ "$action" = "add" -o "$action" = "old" -o "$action" = "del" ]; then |
| if [ -n "$mac" -o "$action" = "del" ]; then |
| sed "/^${ip//./\.} / d" "$STATUS_FILE" > "$STATUS_FILE".new |
| |
| if [ "$action" = "add" -o "$action" = "old" ]; then |
| echo "$ip $mac" >> "$STATUS_FILE".new |
| fi |
| mv "$STATUS_FILE".new "$STATUS_FILE" # atomic update. |
| fi |
| fi |
