mdns: add the new openwrt mdns daemon

this is still wip, you can use the following ubus calls.

ubus call mdns scan	# triggers a scan
ubus call mdns browse	# look at the currenlty cached records
ubus call mdns hosts	# look at the currenlty cached hosts

TODO
- ipv6, currenlty AAAA records are handled but only on v4 sockets
- finish the service announce code

Signed-off-by: John Crispin <blogic@openwrt.org>

SVN-Revision: 41345

package/network/services/mdns/Makefile

@@ -0,0 +1,41 @@
+#
+# Copyright (C) 2014 OpenWrt.org
+#
+# This is free software, licensed under the GNU General Public License v2.
+# See /LICENSE for more information.
+#
+
+include $(TOPDIR)/rules.mk
+
+PKG_NAME:=mdns
+PKG_VERSION:=2014-06-25
+PKG_RELEASE=$(PKG_SOURCE_VERSION)
+
+PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.bz2
+PKG_SOURCE_SUBDIR:=$(PKG_NAME)-$(PKG_VERSION)
+PKG_SOURCE_URL:=git://git.openwrt.org/project/mdnsd.git
+PKG_SOURCE_PROTO:=git
+PKG_SOURCE_VERSION:=902e2d1eaaff0d3d33dee605a4746fd5d4b6b999
+
+PKG_MAINTAINER:=John Crispin <blogic@openwrt.org>
+
+include $(INCLUDE_DIR)/package.mk
+include $(INCLUDE_DIR)/cmake.mk
+
+define Package/mdns
+  SECTION:=net
+  CATEGORY:=Network
+  TITLE:=OpenWrt Multicast DNS Daemon
+  DEPENDS:=+libubox +libubus +libblobmsg-json
+endef
+
+TARGET_CFLAGS += -I$(STAGING_DIR)/usr/include
+
+define Package/mdns/install
+	$(INSTALL_DIR) $(1)/usr/sbin $(1)/etc/init.d $(1)/etc/config
+	$(INSTALL_BIN) $(PKG_BUILD_DIR)/mdns $(1)/usr/sbin/
+	$(INSTALL_BIN) ./files/mdns.init $(1)/etc/init.d/mdns
+	$(INSTALL_BIN) ./files/mdns.config $(1)/etc/config/mdns
+endef
+
+$(eval $(call BuildPackage,mdns))

package/network/services/mdns/files/mdns.config

@@ -0,0 +1,2 @@
+config mdns
+	list network lan

package/network/services/mdns/files/mdns.init

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+#!/bin/sh /etc/rc.common
+# Copyright (c) 2014 OpenWrt.org
+
+. /lib/functions/network.sh
+
+START=80
+
+USE_PROCD=1
+PROG=/usr/sbin/mdns
+IFACES=""
+
+load_ifaces() {
+	local network="$(uci get mdns.@mdns[-1].network)"
+	for n in $network; do
+		local device
+		json_load "$(ifstatus $network)"
+		json_get_var device l3_device
+		echo -n "$device "
+	done
+}
+
+reload_service() {
+	json_init
+	json_add_array interfaces
+	for i in $(load_ifaces); do
+		json_add_string "" "$i"
+	done
+	json_close_array
+
+	ubus call mdns set_config "$(json_dump)"
+}
+
+start_service() {
+	local network="$(uci get mdns.@mdns[-1].network)"
+
+	procd_open_instance
+	procd_set_param command "$PROG"
+	procd_set_param respawn
+	procd_open_trigger
+	procd_add_config_trigger "config.change" "mdns" /etc/init.d/mdns reload
+	for n in $network; do
+		procd_add_interface_trigger "interface.*" $n /etc/init.d/mdns reload	
+	done
+	procd_close_trigger
+	procd_close_instance
+}
+
+service_started() {
+	ubus wait_for -t 5 mdns
+	[ $? = 0 ] && reload_service
+}