make dnsmasq probe for dhcp servers before starting a dhcp server

git-svn-id: svn://svn.openwrt.org/openwrt/trunk/openwrt@1110 3c298f89-4303-0410-b956-a3cf2f4a3e73

1 files changed, 24 insertions, 1 deletions

diff --git a/target/default/target_skeleton/etc/init.d/S50dnsmasq b/target/default/target_skeleton/etc/init.d/S50dnsmasq
index 995c1b6e7..55bbc3719 100755
--- a/target/default/target_skeleton/etc/init.d/S50dnsmasq
+++ b/target/default/target_skeleton/etc/init.d/S50dnsmasq
@@ -1,2 +1,25 @@
 #!/bin/sh
-/usr/sbin/dnsmasq
+. /etc/functions.sh
+
+# interface to use for DHCP
+iface=lan
+
+ifname=$(nvram get ${iface}_ifname)
+ipaddr=$(nvram get ${iface}_ipaddr)
+netmask=$(nvram get ${iface}_netmask)
+
+# check for existing DHCP server
+udhcpc -n -q -R -s /dev/zero -i $ifname >&- || {
+
+  ipaddr=$(ip2int $ipaddr)
+  netmask=$(ip2int ${netmask:-255.255.255.0})
+  network=$((ipaddr&netmask))
+  
+  start=$(nvram get dhcp_start)
+  start=$((network+${start:-100}))
+  end=$(nvram get dhcp_num)
+  end=$((start+${end:-150}))
+  
+  args="-K -F $(int2ip $start),$(int2ip $end),$(int2ip $netmask),12h"
+}
+/usr/sbin/dnsmasq ${args}