ruantiblock-mod-lua: included iptool.lua.

ruantiblock-mod-lua/files/usr/lib/lua/iptool.lua

@@ -0,0 +1,165 @@
+--[[
+ (с) 2020 gSpot <https://github.com/gSpotx2f>
+
+ Some functions for manipulating IPv4 addresses.
+
+ validate_ip(ip)
+ ip_to_int(ip)
+ int_to_ip(ip)
+ summarize_address_range(first, last)
+ get_network_addr(network)
+ hosts_from_network(ip)
+ get_supernet(network, new_prefix)
+
+ lua == 5.1
+ depends: lua-bitop
+--]]
+
+local bit = require("bit")
+local bnot, band, bor = bit.bnot, bit.band, bit.bor
+local bxor, lshift, rshift = bit.bxor, bit.lshift, bit.rshift
+
+local ipv4_length = 32
+local ipv4_capacity = 2 ^ ipv4_length - 1
+local ipaddr_pattern = "^(%d%d?%d?)%.(%d%d?%d?)%.(%d%d?%d?)%.(%d%d?%d?)$"
+local cidr_pattern = "^(%d%d?%d?%.%d%d?%d?%.%d%d?%d?%.%d%d?%d?)/(%d%d?)$"
+
+local function bit_length(n)
+    if n == 0 then
+        return 0
+    elseif n < 0 then
+        n = -n
+    end
+    local i = 1
+    repeat
+        local s = rshift(n, i)
+        i = i + 1
+    until s <= 0
+    return i - 1
+end
+
+local function check_ip(...)
+    if not ... then
+        return false
+    end
+    for _, i in ipairs{...} do
+        if type(i) ~= "number" or (0 > i or i > 255) then
+            return false
+        end
+    end
+    return true
+end
+
+local function check_prefix(n)
+    if type(n) ~= "number" or (0 > n or n > 32) then
+        return false
+    end
+    return true
+end
+
+local function validate_ip(ip)
+    local a, b, c, d, e = ip:match("^(%d%d?%d?)%.(%d%d?%d?)%.(%d%d?%d?)%.(%d%d?%d?)/?(%d?%d?)$")
+    if check_ip(tonumber(a), tonumber(b), tonumber(c), tonumber(d)) and
+        (#e == 0 or check_prefix(tonumber(e))) then
+        return true
+    end
+    return false
+end
+
+local function ip_to_int(ip)
+    if type(ip) == "number" then
+        return ip
+    else
+        local a, b, c, d = ip:match(ipaddr_pattern)
+        return a and tonumber(a) * 16777216 + tonumber(b) * 65536 + tonumber(c) * 256 + tonumber(d) or nil
+    end
+end
+
+local function int_to_ip(number)
+    local octets = {}
+    for i = 1, 4 do
+        table.insert(octets, 1, tostring(band(number, 255)))
+        number = rshift(number, 8)
+    end
+    return table.concat(octets, ".")
+end
+
+local function count_righthand_zero_bits(number, bits)
+    return (number == 0) and bits or math.min(bits, bit_length(band(bnot(number), (number - 1))))
+end
+
+local function summarize_address_range(first, last)
+    local ip_bits = ipv4_length
+    first, last = ip_to_int(first), ip_to_int(last)
+    local ret_val
+    return function()
+        if first > last then
+            return
+        end
+        local nbits = math.min(count_righthand_zero_bits(first, ip_bits), bit_length(last - first + 1) - 1)
+        ret_val = {[1] = first, [2] = (ip_bits - nbits)}
+        first = first + lshift(1, nbits)
+        if first - 1 == ipv4_capacity then
+            return
+        end
+        return ret_val
+    end
+end
+
+local function get_network_addr(network)
+    local ip, pref = network:match(cidr_pattern)
+    return ip and ip_to_int(ip), tonumber(pref)
+end
+
+local function hosts_from_network(network)
+    local network_address, prefixlen
+    if type(network) == "string" then
+        network_address, prefixlen = get_network_addr(network)
+    elseif type(network) == "table" then
+        network_address, prefixlen = network[1], network[2]
+    else
+        return
+    end
+    local last_ip = network_address + (lshift(1, 32 - prefixlen) - 2)
+    local ret_val
+    local current_ip = network_address
+    return function()
+        current_ip = current_ip + 1
+        if (prefixlen == 31 and current_ip - 2 or current_ip) <= last_ip then
+            ret_val = current_ip
+        else
+            ret_val = nil
+        end
+        return ret_val
+    end
+end
+
+local function get_supernet(network, new_prefix)
+    local network_address, prefixlen
+    if type(network) == "string" then
+        network_address, prefixlen = get_network_addr(network)
+    elseif type(network) == "table" then
+        network_address, prefixlen = network[1], network[2]
+    else
+        return
+    end
+    if new_prefix > prefixlen then
+        error("new_prefix must be shorter")
+    end
+    local netmask = bxor(ipv4_capacity, rshift(ipv4_capacity, prefixlen))
+    if netmask < 0 then
+        netmask = netmask + ipv4_capacity + 1
+    end
+    local diff_prefixlen = prefixlen - new_prefix
+    return band(network_address, lshift(netmask, diff_prefixlen))
+end
+
+return {
+    validate_ip = validate_ip,
+    ip_to_int = ip_to_int,
+    int_to_ip = int_to_ip,
+    summarize_address_range = summarize_address_range,
+    get_network_addr = get_network_addr,
+    hosts_from_network = hosts_from_network,
+    get_supernet = get_supernet,
+}