isc-dhcp: add dynamic dns integration for local bind server

Start after named is running.

Add support for "cname", "domain", "mxhost", and "srvhost" configs.

Signed-off-by: Philip Prindeville <philipp@redfish-solutions.com>

net/isc-dhcp/Makefile

@@ -10,7 +10,7 @@ include $(TOPDIR)/rules.mk
 PKG_NAME:=isc-dhcp
 UPSTREAM_NAME:=dhcp
 PKG_VERSION:=4.4.1
-PKG_RELEASE:=11
+PKG_RELEASE:=12
 
 PKG_LICENSE:=BSD-3-Clause
 PKG_LICENSE_FILES:=LICENSE
@@ -109,12 +109,14 @@ define Package/isc-dhcp-server-ipv4
   $(call Package/isc-dhcp/Default)
   TITLE+= server (without IPv6)
   VARIANT:=ipv4
+  DEPENDS+=bind-server bind-client
 endef
 
 define Package/isc-dhcp-server-ipv6
   $(call Package/isc-dhcp/Default)
   TITLE+= server (with IPv6)
   VARIANT:=ipv6
+  DEPENDS+=bind-server bind-client
 endef
 
 define Package/isc-dhcp-server/description

net/isc-dhcp/files/dhcpd.init

@@ -1,12 +1,23 @@
 #!/bin/sh /etc/rc.common
 
-START=19
+START=25
 USE_PROCD=1
 PROG=/usr/sbin/dhcpd
 
+TTL=3600
+PREFIX="update add"
+
 lease_file=/tmp/dhcpd.leases
 config_file=/tmp/run/dhcpd.conf
 
+dyndir=/tmp/bind
+conf_local_file=$dyndir/named.conf.local
+
+session_key_name=local-ddns
+session_key_file=/var/run/named/session.key
+
+dyn_file=$(mktemp -u /tmp/dhcpd.XXXXXX)
+
 time2seconds() {
 	local timestring=$1
 	local multiplier number suffix
@@ -67,12 +78,36 @@ typeof() {
 '
 }
 
+rev_quad() {
+	local ip="$1"
+
+	echo "$ip" | awk -F '.' '{ printf "%s.%s.%s.%s\n", $4, $3, $2, $1; }'
+}
+
+update() {
+	local lhs="$1" family="$2" type="$3"
+	shift 3
+
+	echo -e "$PREFIX" "$lhs $family $type $@\nsend"
+}
+
 explode() {
 	local arg="$1"
 
 	echo "$arg" | sed -e 's/\./, /g'
 }
 
+create_empty_zone()
+{
+	local zone="$1"
+
+	if [ ! -f $dyndir/db."$zone" ]; then
+		cp -p /etc/bind/db.empty $dyndir/db."$zone"
+		chmod g+w $dyndir/db."$zone"
+		chgrp bind $dyndir/db."$zone"
+	fi
+}
+
 append_routes() {
 	local tuple tuples="$1"
 	local string=
@@ -122,6 +157,85 @@ append_dhcp_options() {
 	echo " option $tag $formatted;"
 }
 
+static_cname_add() {
+	local cfg="$1"
+	local cname target
+
+	config_get cname "$cfg" "cname"
+	[ -n "$cname" ] || return 0
+	config_get target "$cfg" "target"
+	[ -n "$target" ] || return 0
+
+	update "$cname.$domain." IN CNAME "$target.$domain."
+}
+
+static_cnames() {
+	config_foreach static_cname_add cname "$@"
+}
+
+static_domain_add() {
+	local cfg="$1"
+	local name ip revip
+
+	config_get name "$cfg" "name"
+	[ -n "$name" ] || return 0
+	config_get ip "$cfg" "ip"
+	[ -n "$ip" ] || return 0
+
+	revip="$(rev_quad "$ip")"
+
+	update "$name.$domain." IN A "$ip"
+	update "$revip.in-addr.arpa." IN PTR "$name.$domain."
+}
+
+static_domains() {
+	config_foreach static_domain_add domain "$@"
+}
+
+static_mxhost_add() {
+	local cfg="$1"
+	local domain2 relay pref
+
+	config_get domain2 "$cfg" "domain"
+	[ -n "$domain2" ] || return 0
+	config_get relay "$cfg" "relay"
+	[ -n "$relay" ] || return 0
+	config_get pref "$cfg" "pref"
+	[ -n "$pref" ] || return 0
+
+	if [ "$domain2" = "@" ]; then
+		update "$domain." IN MX "$pref" "$relay.$domain."
+	else
+		update "$domain2.$domain." IN MX "$pref" "$relay.$domain."
+	fi
+}
+
+static_mxhosts() {
+	config_foreach static_mxhost_add mxhost "$@"
+}
+
+static_srvhost_add() {
+	local cfg="$1"
+	local srv target port priority weight
+
+	config_get srv "$cfg" "srv"
+	[ -n "$srv" ] || return 0
+	config_get target "$cfg" "target"
+	[ -n "$target" ] || return 0
+	config_get port "$cfg" "port"
+	[ -n "$port" ] || return 0
+	config_get priority "$cfg" "priority"
+	[ -n "$priority" ] || return 0
+	config_get weight "$cfg" "weight"
+	[ -n "$weight" ] || return 0
+
+	update "$srv.$domain." IN SRV "$priority" "$weight" "$port" "$target"
+}
+
+static_srvhosts() {
+	config_foreach static_srvhost_add srvhost "$@"
+}
+
 static_host_add() {
 	local cfg="$1"
 	local broadcast hostid macn macs mac name ip leasetime
@@ -278,6 +392,7 @@ general_config() {
 	config_get log_facility "isc_dhcpd" "log_facility"
 
 	config_get domain "isc_dhcpd" "domain"
+	config_get_bool dynamicdns "isc_dhcpd" dynamicdns 0
 
 	[ $always_broadcast -eq 1 ] && echo "always-broadcast true;"
 	[ $authoritative -eq 1 ] && echo "authoritative;"
@@ -288,6 +403,56 @@ general_config() {
 	max_lease_time="$(time2seconds "$max_lease_time")"
 	[ "$?" -ne 0 ] && return 1
 
+	if [ $dynamicdns -eq 1 ]; then
+		create_empty_zone "$domain"
+
+		create_empty_zone "168.192.in-addr.arpa"
+
+		cat <<EOF > $conf_local_file
+zone "$domain" {
+  type master;
+  file "$dyndir/db.$domain";
+  allow-update { key $session_key_name; };
+  allow-transfer { key $session_key_name; };
+};
+
+zone "168.192.in-addr.arpa" {
+  type master;
+  file "$dyndir/db.168.192.in-addr.arpa";
+  allow-update { key $session_key_name; };
+  allow-transfer { key $session_key_name; };
+};
+
+EOF
+		/etc/init.d/named reload
+		sleep 1
+
+		cat <<EOF
+ddns-domainname "$domain.";
+ddns-update-style standard;
+ddns-updates on;
+ignore client-updates;
+
+update-static-leases on;
+use-host-decl-names on;
+update-conflict-detection off;
+update-optimization off;
+
+include "$session_key_file";
+
+zone $domain. {
+	primary 127.0.0.1;
+	key local-ddns;
+}
+
+zone 168.192.in-addr.arpa. {
+	primary 127.0.0.1;
+	key local-ddns;
+}
+
+EOF
+	fi
+
 	if [ -n "$log_facility" ] ; then
 		echo "log-facility $log_facility;"
 	fi
@@ -312,7 +477,7 @@ boot() {
 }
 
 start_service() {
-	local domain dhcp_ifs authoritative
+	local domain dhcp_ifs authoritative dynamicdns
 
 	if [ -n "$DHCPD_BOOT" ] ; then
 		return 0
@@ -335,6 +500,27 @@ start_service() {
 
 		static_hosts >> $config_file
 
+		if [ $dynamicdns -eq 1 ]; then
+			cat <<EOF > $dyn_file
+; Generated by /etc/init.d/dhcpd at $(date)
+
+ttl $TTL
+
+EOF
+
+			static_cnames >> $dyn_file
+
+			static_domains >> $dyn_file
+
+			static_mxhosts >> $dyn_file
+
+			static_srvhosts >> $dyn_file
+
+			nsupdate -l -v $dyn_file
+
+			rm -f $dyn_file
+		fi
+
 		[ -z "$dhcp_ifs" ] && return 0
 	fi