Add DNS server (#83)

Add DNS server

dhcp_server/run.sh

@@ -0,0 +1,48 @@
+#!/bin/bash
+set -e
+
+CONFIG_PATH=/data/options.json
+
+DOMAIN=$(jq --raw-output '.domain' $CONFIG_PATH)
+DNS=$(jq --raw-output '.dns | join(", ")' $CONFIG_PATH)
+NETWORKS=$(jq --raw-output '.networks | length' $CONFIG_PATH)
+HOSTS=$(jq --raw-output '.hosts | length' $CONFIG_PATH)
+
+sed -i "s/%%DOMAIN%%/$DOMAIN/g" /etc/dhcpd.conf
+sed -i "s/%%DNS_SERVERS%%/$DNS/g" /etc/dhcpd.conf
+
+# Create networks
+for (( i=0; i < "$NETWORKS"; i++ )); do
+    SUBNET=$(jq --raw-output ".networks[$i].subnet" $CONFIG_PATH)
+    NETMASK=$(jq --raw-output ".networks[$i].netmask" $CONFIG_PATH)
+    RANGE_START=$(jq --raw-output ".networks[$i].range_start" $CONFIG_PATH)
+    RANGE_END=$(jq --raw-output ".networks[$i].range_end" $CONFIG_PATH)
+    BROADCAST=$(jq --raw-output ".networks[$i].broadcast" $CONFIG_PATH)
+    ROUTERS=$(jq --raw-output ".networks[$i].routers | joint(\", \")" $CONFIG_PATH)
+
+    {
+        echo "subnet $SUBNET netmask $NETMASK {"
+        echo "  range $RANGE_START $RANGE_END;"
+        echo "  option routers $ROUTERS;"
+        echo "  option broadcast-address $BROADCAST;"
+        echo "}"
+    } >> /etc/dhcpd.conf
+done
+
+# Create hosts
+for (( i=0; i < "$HOSTS"; i++ )); do
+    MAC=$(jq --raw-output ".hosts[$i].mac" $CONFIG_PATH)
+    NAME=$(jq --raw-output ".hosts[$i].name" $CONFIG_PATH)
+    IP=$(jq --raw-output ".hosts[$i].ip" $CONFIG_PATH)
+
+    {
+        echo "host $NAME {"
+        echo "  hardware ethernet $MAC;"
+        echo "  fixed-address $IP;"
+        echo "  option host-name \"$NAME\";"
+        echo "}"
+    } >> /etc/dhcpd.conf
+done
+
+# run dhcp server
+exec /usr/sbin/dhcpd -4 -f -d --no-pid -lf /data/dhcpd.lease -cf /etc/dhcpd.conf < /dev/null