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-- Copyright (c) 2018-2021, OARC, Inc.
-- All rights reserved.
--
-- This file is part of dnsjit.
--
-- dnsjit is free software: you can redistribute it and/or modify
-- it under the terms of the GNU General Public License as published by
-- the Free Software Foundation, either version 3 of the License, or
-- (at your option) any later version.
--
-- dnsjit is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-- GNU General Public License for more details.
--
-- You should have received a copy of the GNU General Public License
-- along with dnsjit. If not, see <http://www.gnu.org/licenses/>.
-- dnsjit.lib.ip
-- IP address utility library
-- local ip = require("dnsjit.lib.ip")
-- print(ip.ipstring(ipv4_cdata))
-- print(ip.ip6string(ipv6_cdata), true)
--
-- A library to help with various IP address related tasks, such as
-- printing them.
module(...,package.seeall)
local ffi = require("ffi")
Ip = {}
-- Return an IPv4 or IPv6 address as a string.
-- If it's an IPv6 address the optional argument
-- .I pretty
-- is true then return an easier to read IPv6 address.
-- Return an empty string on invalid input.
function Ip.tostring(ip, pretty)
if type(ip) == "cdata" then
if ffi.sizeof(ip) == 4 then
return Ip.ipstring(ip)
elseif ffi.sizeof(ip) == 16 then
return Ip.ip6string(ip, pretty)
end
end
return ""
end
-- Return a IPv4 address as a string.
-- The input is a 4-byte cdata array.
function Ip.ipstring(ip)
return ip[0] ..".".. ip[1] ..".".. ip[2] ..".".. ip[3]
end
local function _pretty(ip)
local src = {}
local n, nn
nn = 1
for n = 0, 15, 2 do
if ip[n] ~= 0 then
src[nn] = string.format("%x%02x", ip[n], ip[n + 1])
elseif ip[n + 1] ~= 0 then
src[nn] = string.format("%x", ip[n + 1])
else
src[nn] = "0"
end
nn = nn + 1
end
local best_n, best_at, at = 0, 0, 0
n = 0
for nn = 1, 8 do
if src[nn] == "0" then
if n == 0 then
at = nn
end
n = n + 1
else
if n > 0 then
if n > best_n then
best_n = n
best_at = at
end
n = 0
end
end
end
if n > 0 then
if n > best_n then
best_n = n
best_at = at
end
end
if best_n > 1 then
for n = 2, best_n do
table.remove(src, best_at)
end
if best_at == 1 or best_at + best_n > 8 then
src[best_at] = ":"
else
src[best_at] = ""
end
end
return table.concat(src,":")
end
-- Return the IPv6 address as a string.
-- The input is a 16-byte cdata array.
-- If
-- .I pretty
-- is true then return an easier to read IPv6 address.
function Ip.ip6string(ip6, pretty)
if pretty == true then
return _pretty(ip6)
end
return string.format("%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x:%02x%02x",
ip6[0], ip6[1], ip6[2], ip6[3], ip6[4], ip6[5], ip6[6], ip6[7],
ip6[8], ip6[9], ip6[10], ip6[11], ip6[12], ip6[13], ip6[14], ip6[15])
end
-- dnsjit.core.object.ip (3),
-- dnsjit.core.object.ip6 (3)
return Ip
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