1 files changed, 125 insertions, 0 deletions
diff --git a/include/dnsjit/lib/ip.lua b/include/dnsjit/lib/ip.lua
new file mode 100644
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--- /dev/null
+++ b/include/dnsjit/lib/ip.lua
@@ -0,0 +1,125 @@
+-- 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