* luci/libs: added broadcast(), minhost() and maxhost() to luci.ip, allow various datatypes as add() and sub() operands, extended add() and sub() to modify data inplace when flag is set

libs/core/luasrc/ip.lua

@@ -41,21 +41,49 @@ local function __bless(x)
 	} )
 end
 
-local function __mask16(bits)
+local function __array16( x, family )
-	return bit.lshift(
+	local list
-		bit.rshift( 0xFFFF, 16 - bits % 16 ),
+
-		16 - bits % 16
+	if type(x) == "number" then
-	)
+		list = { bit.rshift(x, 16), bit.band(x, 0xFFFF) }
+
+	elseif type(x) == "string" then
+		if x:find(":") then x = IPv6(x) else x = IPv4(x) end
+		if x then
+			assert( x[1] == family, "Can't mix IPv4 and IPv6 addresses" )
+			list = { unpack(x[2]) }
 		end
 
-local function __length(family)
+	elseif type(x) == "table" and type(x[2]) == "table" then
-	if family == FAMILY_INET4 then
+		assert( x[1] == family, "Can't mix IPv4 and IPv6 addresses" )
-		return 32
+		list = { unpack(x[2]) }
-	else
+
-		return 128
+	elseif type(x) == "table" then
+		list = x
 	end
+
+	assert( list, "Invalid operand" )
+
+	return list
 end
 
+local function __mask16(bits)
+	return bit.lshift( bit.rshift( 0xFFFF, 16 - bits % 16 ), 16 - bits % 16 )
+end
+
+local function __not16(bits)
+	return bit.band( bit.bnot( __mask16(bits) ), 0xFFFF )
+end
+
+local function __maxlen(family)
+	return ( family == FAMILY_INET4 ) and 32 or 128
+end
+
+local function __sublen(family)
+	return ( family == FAMILY_INET4 ) and 30 or 127
+end
+
+
 --- Convert given short value to network byte order on little endian hosts
 -- @param x	Unsigned integer value between 0x0000 and 0xFFFF
 -- @return	Byte-swapped value
@@ -255,9 +283,9 @@ end
 function Hex( hex, prefix, family, swap )
 	family = ( family ~= nil ) and family or FAMILY_INET4
 	swap   = ( swap   == nil ) and true   or swap
-	prefix = prefix or __length(family)
+	prefix = prefix or __maxlen(family)
 
-	local len  = __length(family)
+	local len  = __maxlen(family)
 	local tmp  = ""
 	local data = { }
 
@@ -417,6 +445,7 @@ end
 -- @param bits	Override prefix length of this instance (optional)
 -- @return		CIDR instance containing the network address
 -- @see			host
+-- @see			broadcast
 -- @see			mask
 function cidr.network( self, bits )
 	local data = { }
@@ -434,16 +463,17 @@ function cidr.network( self, bits )
 		end
 	end
 
-	return __bless({ self[1], data, __length(self[1]) })
+	return __bless({ self[1], data, __maxlen(self[1]) })
 end
 
 --- Return a corresponding CIDR representing the host address of this
 -- instance. This is intended to extract the host address from larger subnet.
 -- @return		CIDR instance containing the network address
 -- @see			network
+-- @see			broadcast
 -- @see			mask
 function cidr.host( self )
-	return __bless({ self[1], data, __length(self[1]) })
+	return __bless({ self[1], data, __maxlen(self[1]) })
 end
 
 --- Return a corresponding CIDR representing the netmask of this instance.
@@ -451,6 +481,7 @@ end
 -- @return		CIDR instance containing the netmask
 -- @see			network
 -- @see			host
+-- @see			broadcast
 function cidr.mask( self, bits )
 	local data = { }
 	bits = bits or self[3]
@@ -467,7 +498,28 @@ function cidr.mask( self, bits )
 		end
 	end
 
-	return __bless({ self[1], data, __length(self[1]) })
+	return __bless({ self[1], data, __maxlen(self[1]) })
+end
+
+--- Return CIDR containing the broadcast address of this instance.
+-- @param bits	Override prefix length of this instance (optional)
+-- @return		CIDR instance containing the netmask, always nil for IPv6
+-- @see			network
+-- @see			host
+-- @see			mask
+function cidr.broadcast( self )
+	-- IPv6 has no broadcast addresses (XXX: assert() instead?)
+	if self[1] == FAMILY_INET4 then
+		local data   = { unpack(self[2]) }
+		local offset = math.floor( self[3] / 16 ) + 1
+
+		if offset <= #data then
+			data[offset] = bit.bor( data[offset], __not16(self[3]) )
+			for i = offset + 1, #data do data[i] = 0xFFFF end
+
+			return __bless({ self[1], data, __maxlen(self[1]) })
+		end
+	end
 end
 
 --- Test whether this instance fully contains the given CIDR instance.
@@ -485,12 +537,14 @@ end
 
 --- Add specified amount of hosts to this instance.
 -- @param amount	Number of hosts to add to this instance
+-- @param inplace	Boolen indicating whether to alter values inplace (optional)
 -- @return			CIDR representing the new address or nil on overflow error
 -- @see				sub
-function cidr.add( self, amount )
+function cidr.add( self, amount, inplace )
-	local shorts = { bit.rshift(amount, 16), bit.band(amount, 0xFFFF) }
 	local data   = { unpack(self[2]) }
+	local shorts = __array16( amount, self[1] )
 
+	if shorts then
 		for pos = #data, 1, -1 do
 			local add = ( #shorts > 0 ) and table.remove( shorts, #shorts ) or 0
 			if ( data[pos] + add ) > 0xFFFF then
@@ -504,18 +558,26 @@ function cidr.add( self, amount )
 				data[pos] = data[pos] + add
 			end
 		end
+	end
 
+	if inplace then
+		self[2] = data
+		return self
+	else
 		return __bless({ self[1], data, self[3] })
 	end
+end
 
 --- Substract specified amount of hosts from this instance.
 -- @param amount	Number of hosts to substract from this instance
+-- @param inplace	Boolen indicating whether to alter values inplace (optional)
 -- @return			CIDR representing the new address or nil on underflow error
 -- @see				add
-function cidr.sub( self, amount )
+function cidr.sub( self, amount, inplace )
-	local shorts = { bit.rshift(amount, 16), bit.band(amount, 0xFFFF) }
 	local data   = { unpack(self[2]) }
+	local shorts = __array16( amount, self[1] )
 
+	if shorts then
 		for pos = #data, 1, -1 do
 			local sub = ( #shorts > 0 ) and table.remove( shorts, #shorts ) or 0
 			if ( data[pos] - sub ) < 0 then
@@ -529,6 +591,41 @@ function cidr.sub( self, amount )
 				data[pos] = data[pos] - sub
 			end
 		end
+	end
 
+	if inplace then
+		self[2] = data
+		return self
+	else
 		return __bless({ self[1], data, self[3] })
 	end
+end
+
+--- Return CIDR containing the lowest available host address within this subnet.
+-- @return		CIDR containing the host address, nil if subnet is too small
+-- @see			maxhost
+function cidr.minhost( self )
+	if self[3] <= __sublen(self[1]) then
+		-- 1st is Network Address in IPv4 and Subnet-Router Anycast Adresse in IPv6
+		return self:network():add(1, true)
+	end
+end
+
+--- Return CIDR containing the highest available host address within the subnet.
+-- @return		CIDR containing the host address, nil if subnet is too small
+-- @see			minhost
+function cidr.maxhost( self )
+	if self[3] <= __sublen(self[1]) then
+		local data   = { unpack(self[2]) }
+		local offset = math.floor( self[3] / 16 ) + 1
+
+		data[offset] = bit.bor( data[offset], __not16(self[3]) )
+		for i = offset + 1, #data do data[i] = 0xFFFF end
+		data = __bless({ self[1], data, __maxlen(self[1]) })
+
+		-- Last address in reserved for Broadcast Address in IPv4
+		if data[1] == FAMILY_INET4 then data:sub(1, true) end
+
+		return data
+	end
+end