[LEDE-DEV] [PATCH] busybox: sysntpd - Support for NTP servers received via DHCP(v6)

[Jo-Philipp Wich]

Hi Hans,

staged into https://git.lede-project.org/?p=lede/jow/staging.git

A few improvement ideas though;

 - maybe we can make the jsonfilter dependency conditionally depending
   on the ntpd applet
 - maybe pipe the ubus interface status dump directly to jsonfilter
 - is there any reason to not make "use_dhcp" the default?

~ Jo

On 05/19/2016 06:57 PM, Hans Dedecker wrote:
> The busybox ntpd utility currently uses ntp servers specified in uci.
> This patch allows the ntpd utility to use NTP servers received via DHCP(v6)
> Following uci parameters have been added:
>     use_dhcp : enables NTP server config via DHCP(v6)
>     dhcp_interface : use NTP servers received only on the specified DHCP(v6) interfaces; if empty all interfaces are considered
> 
> Signed-off-by: Hans Dedecker <dedeckeh at gmail.com>
> ---
> 
> The patch is based on a previous discussion held on the OpenWRT-devel mailing list
> (https://lists.openwrt.org/pipermail/openwrt-devel/2016-January/039081.html) as per Felix's
> comments this solution is based on procd interface service triggers
> 
>  package/utils/busybox/Makefile      |  2 +-
>  package/utils/busybox/files/sysntpd | 43 ++++++++++++++++++++++++++++++++-----
>  2 files changed, 39 insertions(+), 6 deletions(-)
> 
> diff --git a/package/utils/busybox/Makefile b/package/utils/busybox/Makefile
> index 24c064c..24e0e11 100644
> --- a/package/utils/busybox/Makefile
> +++ b/package/utils/busybox/Makefile
> @@ -42,7 +42,7 @@ define Package/busybox
>    MAINTAINER:=Felix Fietkau <nbd at openwrt.org>
>    TITLE:=Core utilities for embedded Linux
>    URL:=http://busybox.net/
> -  DEPENDS:=+BUSYBOX_USE_LIBRPC:librpc +BUSYBOX_CONFIG_PAM:libpam
> +  DEPENDS:=+BUSYBOX_USE_LIBRPC:librpc +BUSYBOX_CONFIG_PAM:libpam +jsonfilter
>    MENU:=1
>  endef
>  
> diff --git a/package/utils/busybox/files/sysntpd b/package/utils/busybox/files/sysntpd
> index f73bb83..5c663d7 100755
> --- a/package/utils/busybox/files/sysntpd
> +++ b/package/utils/busybox/files/sysntpd
> @@ -7,13 +7,35 @@ USE_PROCD=1
>  PROG=/usr/sbin/ntpd
>  HOTPLUG_SCRIPT=/usr/sbin/ntpd-hotplug
>  
> +get_dhcp_ntp_servers() {
> +	local interfaces="$1"
> +	local filter="*"
> +	local network_dump interface ntpservers ntpserver
> +
> +	network_dump=$(ubus call network.interface dump)
> +	for interface in $interfaces; do
> +		[ "$filter" = "*" ] && filter="@.interface='$interface'" || filter="$filter, at .interface='$interface'"
> +	done
> +
> +	ntpservers=$(jsonfilter -s "$network_dump" -e "@.interface[$filter]['data']['ntpserver']")
> +
> +	for ntpserver in $ntpservers; do
> +		local duplicate=0
> +		local entry
> +		for entry in $server; do
> +			[ "$ntpserver" = "$entry" ] && duplicate=1
> +		done
> +		[ "$duplicate" = 0 ] && server="$server $ntpserver"
> +	done
> +}
> +
>  validate_ntp_section() {
>  	uci_validate_section system timeserver "${1}" \
> -		'server:list(host)' 'enabled:bool:1' 'enable_server:bool:0'
> +		'server:list(host)' 'enabled:bool:1' 'enable_server:bool:0' 'use_dhcp:bool:0' 'dhcp_interface:list(string)'
>  }
>  
>  start_service() {
> -	local server enabled enable_server peer
> +	local server enabled enable_server use_dhcp dhcp_interface peer
>  
>  	validate_ntp_section ntp || {
>  		echo "validation failed"
> @@ -22,6 +44,8 @@ start_service() {
>  
>  	[ $enabled = 0 ] && return
>  
> +	[ $use_dhcp = 1 ] && get_dhcp_ntp_servers "$dhcp_interface"
> +
>  	[ -z "$server" ] && return
>  
>  	procd_open_instance
> @@ -35,8 +59,17 @@ start_service() {
>  	procd_close_instance
>  }
>  
> -service_triggers()
> -{
> -	procd_add_reload_trigger "system"
> +service_triggers() {
> +	local script name
> +
> +	script=$(readlink -f "$initscript")
> +	name=$(basename ${script:-$initscript})
> +
> +	procd_open_trigger
> +	procd_add_config_trigger "config.change" "system" /etc/init.d/$name reload
> +
> +	procd_add_raw_trigger "interface.*" 2000 /etc/init.d/$name reload
> +	procd_close_trigger
> +
>  	procd_add_validation validate_ntp_section
>  }
>