base-files: various enhancements to network.sh

- support reading inactive gateways and DNS information in
	  network_get_gateway(), network_get_dnsserver() and network_get_dnssearch()
	  by passing "true" as optional last argument
	- internally cache fetched values to speed up subsequent accesses to the same
	  data, introduce network_flush_cache() to clear them
	- add some inline function documentation

SVN-Revision: 34722

package/base-files/Makefile

@@ -11,7 +11,7 @@ include $(INCLUDE_DIR)/kernel.mk
 include $(INCLUDE_DIR)/version.mk
 
 PKG_NAME:=base-files
-PKG_RELEASE:=120
+PKG_RELEASE:=121
 
 PKG_FILE_DEPENDS:=$(PLATFORM_DIR)/ $(GENERIC_PLATFORM_DIR)/base-files/
 PKG_BUILD_DEPENDS:=opkg/host

package/base-files/files/lib/functions/network.sh

@@ -1,11 +1,40 @@
 . /usr/share/libubox/jshn.sh
 
+__network_switch_inactive()
+{
+	local __tmp
+
+	if [ "$1" = 0 ] || [ "$1" = false ]; then
+		return 1
+	fi
+
+	json_get_type __tmp "inactive"
+
+	if [ "$__tmp" = object ]; then
+		json_select "inactive"
+	fi
+}
+
+__network_set_cache()
+{
+	__NETWORK_CACHE="${__NETWORK_CACHE:+$__NETWORK_CACHE }__NETWORK_CV_$1"
+	eval "__NETWORK_CV_$1='\$$2'"
+}
+
+__network_get_cache()
+{
+	eval "[ -n \"\${__NETWORK_CV_$1+x}\" ] && export -- \"$2=\$__NETWORK_CV_$1\""
+}
+
 __network_ipaddr()
 {
 	local __var="$1"
 	local __iface="$2"
 	local __family="$3"
-	local __prefix="${4:-0}"
+	local __prefix="$4"
+	local __key="ipaddr_${2}_${3}_${4}"
+
+	__network_get_cache "$__key" "$__var" && return 0
 
 	local __tmp="$(ubus call network.interface."$__iface" status 2>/dev/null)"
 
@@ -27,6 +56,7 @@ __network_ipaddr()
 				eval "export -- \"$__var=\${$__var}/$__tmp\""
 			}
 
+			__network_set_cache "$__key" "$__var"
 			return 0
 		fi
 	fi
@@ -34,10 +64,24 @@ __network_ipaddr()
 	return 1
 }
 
+# determine IPv4 address of given logical interface
+# 1: destination variable
+# 2: interface
 network_get_ipaddr()  { __network_ipaddr "$1" "$2" 4 0; }
+
+# determine IPv6 address of given logical interface
+# 1: destination variable
+# 2: interface
 network_get_ipaddr6() { __network_ipaddr "$1" "$2" 6 0; }
 
+# determine IPv4 subnet of given logical interface
+# 1: destination variable
+# 2: interface
 network_get_subnet()  { __network_ipaddr "$1" "$2" 4 1; }
+
+# determine IPv6 subnet of given logical interface
+# 1: destination variable
+# 2: interface
 network_get_subnet6() { __network_ipaddr "$1" "$2" 6 1; }
 
 
@@ -46,16 +90,21 @@ __network_gateway()
 	local __var="$1"
 	local __iface="$2"
 	local __family="$3"
+	local __key="gateway_${2}_${3}"
+
+	__network_get_cache "$__key" "$__var" && return 0
 
 	local __tmp="$(ubus call network.interface."$__iface" status 2>/dev/null)"
-	local __idx=1
 
 	json_load "${__tmp:-{}}"
 
+	for __tmp in 0 1; do
+
 		if json_get_type __tmp route && [ "$__tmp" = array ]; then
 
 			json_select route
 
+			local __idx=1
 			while json_get_type __tmp "$__idx" && [ "$__tmp" = object ]; do
 
 				json_select "$((__idx++))"
@@ -64,6 +113,7 @@ __network_gateway()
 				case "${__family}/${__tmp}" in
 					4/0.0.0.0|6/::)
 						json_get_var "$__var" nexthop
+						__network_set_cache "$__key" "$__var"
 						return $?
 					;;
 				esac
@@ -71,54 +121,96 @@ __network_gateway()
 				json_select ".."
 
 			done
+
+			json_select ".."
+
 		fi
 
+		__network_switch_inactive "$4" || break
+
+	done
+
 	return 1
 }
 
-network_get_gateway()  { __network_gateway "$1" "$2" 4; }
+# determine IPv4 gateway of given logical interface
-network_get_gateway6() { __network_gateway "$1" "$2" 6; }
+# 1: destination variable
+# 2: interface
+# 3: consider inactive gateway if "true" (optional)
+network_get_gateway()  { __network_gateway "$1" "$2" 4 "${3:-0}"; }
+
+# determine  IPv6 gateway of given logical interface
+# 1: destination variable
+# 2: interface
+# 3: consider inactive gateway if "true" (optional)
+network_get_gateway6() { __network_gateway "$1" "$2" 6 "${3:-0}"; }
 
 
 __network_dns() {
 	local __var="$1"
 	local __iface="$2"
 	local __field="$3"
+	local __key="dns_${2}_${3}"
+
+	__network_get_cache "$__key" "$__var" && return 0
 
 	local __tmp="$(ubus call network.interface."$__iface" status 2>/dev/null)"
 	local __dns=""
-	local __idx=1
 
 	json_load "${__tmp:-{}}"
 
+	for __tmp in 0 1; do
+
 		if json_get_type __tmp "$__field" && [ "$__tmp" = array ]; then
 
 			json_select "$__field"
 
+			local __idx=1
 			while json_get_type __tmp "$__idx" && [ "$__tmp" = string ]; do
 
 				json_get_var __tmp "$((__idx++))"
 				__dns="${__dns:+$__dns }$__tmp"
 
 			done
+
+			json_select ".."
 		fi
 
+		__network_switch_inactive "$4" || break
+
+	done
+
+	if [ -n "$__dns" ]; then
 		eval "export -- \"$__var=$__dns\""
-	[ -n "$__dns" ]
+		__network_set_cache "$__key" "$__var"
+	fi
 }
 
-network_get_dnsserver() { __network_dns "$1" "$2" dns_server; }
+# determine the DNS servers of the given logical interface
-network_get_dnssearch() { __network_dns "$1" "$2" dns_search; }
+# 1: destination variable
+# 2: interface
+# 3: consider inactive servers if "true" (optional)
+network_get_dnsserver() { __network_dns "$1" "$2" dns_server "${3:-0}"; }
+
+# determine the domains of the given logical interface
+# 1: destination variable
+# 2: interface
+# 3: consider inactive servers if "true" (optional)
+network_get_dnssearch() { __network_dns "$1" "$2" dns_search "${3:-0}"; }
 
 
 __network_wan() {
 	local __var="$1"
 	local __family="$2"
+	local __key="wan_${2}"
 	local __iface
 
+	__network_get_cache "$__key" "$__var" && return 0
+
 	for __iface in $(ubus list | sed -ne 's/^network\.interface\.//p'); do
 		if __network_gateway "$__var" "$__iface" "$__family"; then
 			eval "export -- \"$__var=$__iface\""
+			__network_set_cache "$__key" "$__var"
 			return 0
 		fi
 	done
@@ -127,7 +219,12 @@ __network_wan() {
 	return 1
 }
 
+# find the logical interface which holds the current IPv4 default route
+# 1: destination variable
 network_find_wan()  { __network_wan "$1" 4; }
+
+# find the logical interface which holds the current IPv6 default route
+# 1: destination variable
 network_find_wan6() { __network_wan "$1" 6; }
 
 
@@ -136,21 +233,33 @@ __network_device()
 	local __var="$1"
 	local __iface="$2"
 	local __field="$3"
+	local __key="device_${2}_${3}"
+
+	__network_get_cache "$__key" "$__var" && return 0
 
 	local __tmp="$(ubus call network.interface."$__iface" status 2>/dev/null)"
 	[ -n "$__tmp" ] || return 1
 
 	json_load "$__tmp"
-	json_get_var "$__var" "$__field"
+	json_get_var "$__var" "$__field" && __network_set_cache "$__key" "$__var"
 }
 
+# test whether the given logical interface is running
+# 1: interface
 network_is_up()
 {
 	local __up
 	__network_device __up "$1" up && [ $__up -eq 1 ]
 }
 
+# determine the layer 3 linux network device of the given logical interface
+# 1: destination variable
+# 2: interface
 network_get_device()  { __network_device "$1" "$2" l3_device; }
+
+# determine the layer 2 linux network device of the given logical interface
+# 1: destination variable
+# 2: interface
 network_get_physdev() { __network_device "$1" "$2" device;    }
 
 
@@ -166,5 +275,19 @@ __network_defer()
 	ubus call network.device set_state "$(json_dump)" 2>/dev/null
 }
 
+# defer netifd actions on the given linux network device
+# 1: device name
 network_defer_device() { __network_defer "$1" 1; }
+
+# continue netifd actions on the given linux network device
+# 1: device name
 network_ready_device() { __network_defer "$1" 0; }
+
+# flush the internal value cache to force re-reading values from ubus
+network_flush_cache()
+{
+	local __tmp
+	for __tmp in $__NETWORK_CACHE __NETWORK_CACHE; do
+		unset "$__tmp"
+	done
+}