examples: add example of a DHCP server

As usual, by multiplying directories - "dhcpd_eth0", "dhcpd_wlan1"
you can run many servers on different interfaces.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
diff --git a/examples/var_service/dhcpd_if/udhcpc.conf b/examples/var_service/dhcpd_if/udhcpc.conf
new file mode 100644
index 0000000..a819259
--- /dev/null
+++ b/examples/var_service/dhcpd_if/udhcpc.conf
@@ -0,0 +1,28 @@
+# Directives with defaults:
+# start		192.168.0.20
+# end		192.168.0.254
+# interface	eth0
+# max_leases	235
+# auto_time	7200
+# decline_time	3600
+# conflict_time	3600
+# offer_time	60
+# min_lease	60
+# lease_file	/var/lib/misc/udhcpd.leases
+# pidfile	/var/run/udhcpd.pid
+# siaddr	0.0.0.0
+#
+# Directives with no defaults (or with empty defaults):
+# option/opt	NAME VALUE
+# notify_file	/path/to/script_to_run_after_leasefile_is_written
+#		(it is run with $1 = lease_file_name)
+# sname		dhcp_packet_sname_field_contents
+# boot_file	dhcp_packet_bootfile_field_contents
+# static_lease	XX:XX:XX:XX:XX:XX IP.ADD.RE.SS
+
+interface if
+pidfile		/dev/null
+lease_file	udhcpd.leases
+option		subnet 255.255.255.0
+option		lease  3600
+#option		router 192.168.0.1