mirror of
https://github.com/bjc/prosody.git
synced 2025-04-03 21:27:38 +03:00
1100 lines
29 KiB
Lua
1100 lines
29 KiB
Lua
-- Prosody IM
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-- This file is included with Prosody IM. It has modifications,
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-- which are hereby placed in the public domain.
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-- todo: quick (default) header generation
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-- todo: nxdomain, error handling
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-- todo: cache results of encodeName
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-- reference: http://tools.ietf.org/html/rfc1035
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-- reference: http://tools.ietf.org/html/rfc1876 (LOC)
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local socket = require "socket";
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local timer = require "util.timer";
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local _, windows = pcall(require, "util.windows");
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local is_windows = (_ and windows) or os.getenv("WINDIR");
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local coroutine, io, math, string, table =
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coroutine, io, math, string, table;
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local ipairs, next, pairs, print, setmetatable, tostring, assert, error, unpack, select, type=
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ipairs, next, pairs, print, setmetatable, tostring, assert, error, unpack, select, type;
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local ztact = { -- public domain 20080404 lua@ztact.com
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get = function(parent, ...)
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local len = select('#', ...);
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for i=1,len do
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parent = parent[select(i, ...)];
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if parent == nil then break; end
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end
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return parent;
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end;
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set = function(parent, ...)
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local len = select('#', ...);
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local key, value = select(len-1, ...);
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local cutpoint, cutkey;
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for i=1,len-2 do
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local key = select (i, ...)
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local child = parent[key]
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if value == nil then
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if child == nil then
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return;
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elseif next(child, next(child)) then
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cutpoint = nil; cutkey = nil;
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elseif cutpoint == nil then
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cutpoint = parent; cutkey = key;
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end
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elseif child == nil then
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child = {};
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parent[key] = child;
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end
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parent = child
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end
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if value == nil and cutpoint then
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cutpoint[cutkey] = nil;
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else
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parent[key] = value;
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return value;
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end
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end;
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};
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local get, set = ztact.get, ztact.set;
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local default_timeout = 15;
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-------------------------------------------------- module dns
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module('dns')
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local dns = _M;
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-- dns type & class codes ------------------------------ dns type & class codes
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local append = table.insert
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local function highbyte(i) -- - - - - - - - - - - - - - - - - - - highbyte
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return (i-(i%0x100))/0x100;
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end
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local function augment (t) -- - - - - - - - - - - - - - - - - - - - augment
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local a = {};
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for i,s in pairs(t) do
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a[i] = s;
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a[s] = s;
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a[string.lower(s)] = s;
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end
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return a;
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end
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local function encode (t) -- - - - - - - - - - - - - - - - - - - - - encode
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local code = {};
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for i,s in pairs(t) do
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local word = string.char(highbyte(i), i%0x100);
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code[i] = word;
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code[s] = word;
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code[string.lower(s)] = word;
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end
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return code;
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end
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dns.types = {
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'A', 'NS', 'MD', 'MF', 'CNAME', 'SOA', 'MB', 'MG', 'MR', 'NULL', 'WKS',
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'PTR', 'HINFO', 'MINFO', 'MX', 'TXT',
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[ 28] = 'AAAA', [ 29] = 'LOC', [ 33] = 'SRV',
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[252] = 'AXFR', [253] = 'MAILB', [254] = 'MAILA', [255] = '*' };
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dns.classes = { 'IN', 'CS', 'CH', 'HS', [255] = '*' };
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dns.type = augment (dns.types);
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dns.class = augment (dns.classes);
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dns.typecode = encode (dns.types);
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dns.classcode = encode (dns.classes);
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local function standardize(qname, qtype, qclass) -- - - - - - - standardize
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if string.byte(qname, -1) ~= 0x2E then qname = qname..'.'; end
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qname = string.lower(qname);
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return qname, dns.type[qtype or 'A'], dns.class[qclass or 'IN'];
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end
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local function prune(rrs, time, soft) -- - - - - - - - - - - - - - - prune
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time = time or socket.gettime();
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for i,rr in ipairs(rrs) do
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if rr.tod then
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-- rr.tod = rr.tod - 50 -- accelerated decripitude
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rr.ttl = math.floor(rr.tod - time);
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if rr.ttl <= 0 then
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rrs[rr[rr.type:lower()]] = nil;
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table.remove(rrs, i);
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return prune(rrs, time, soft); -- Re-iterate
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end
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elseif soft == 'soft' then -- What is this? I forget!
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assert(rr.ttl == 0);
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rrs[rr[rr.type:lower()]] = nil;
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table.remove(rrs, i);
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end
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end
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end
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-- metatables & co. ------------------------------------------ metatables & co.
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local resolver = {};
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resolver.__index = resolver;
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resolver.timeout = default_timeout;
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local function default_rr_tostring(rr)
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local rr_val = rr.type and rr[rr.type:lower()];
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if type(rr_val) ~= "string" then
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return "<UNKNOWN RDATA TYPE>";
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end
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return rr_val;
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end
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local special_tostrings = {
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LOC = resolver.LOC_tostring;
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MX = function (rr)
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return string.format('%2i %s', rr.pref, rr.mx);
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end;
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SRV = function (rr)
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local s = rr.srv;
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return string.format('%5d %5d %5d %s', s.priority, s.weight, s.port, s.target);
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end;
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};
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local rr_metatable = {}; -- - - - - - - - - - - - - - - - - - - rr_metatable
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function rr_metatable.__tostring(rr)
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local rr_string = (special_tostrings[rr.type] or default_rr_tostring)(rr);
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return string.format('%2s %-5s %6i %-28s %s', rr.class, rr.type, rr.ttl, rr.name, rr_string);
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end
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local rrs_metatable = {}; -- - - - - - - - - - - - - - - - - - rrs_metatable
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function rrs_metatable.__tostring(rrs)
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local t = {};
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for i,rr in ipairs(rrs) do
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append(t, tostring(rr)..'\n');
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end
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return table.concat(t);
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end
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local cache_metatable = {}; -- - - - - - - - - - - - - - - - cache_metatable
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function cache_metatable.__tostring(cache)
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local time = socket.gettime();
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local t = {};
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for class,types in pairs(cache) do
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for type,names in pairs(types) do
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for name,rrs in pairs(names) do
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prune(rrs, time);
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append(t, tostring(rrs));
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end
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end
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end
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return table.concat(t);
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end
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function resolver:new() -- - - - - - - - - - - - - - - - - - - - - resolver
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local r = { active = {}, cache = {}, unsorted = {} };
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setmetatable(r, resolver);
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setmetatable(r.cache, cache_metatable);
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setmetatable(r.unsorted, { __mode = 'kv' });
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return r;
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end
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-- packet layer -------------------------------------------------- packet layer
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function dns.random(...) -- - - - - - - - - - - - - - - - - - - dns.random
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math.randomseed(math.floor(10000*socket.gettime()) % 0x80000000);
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dns.random = math.random;
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return dns.random(...);
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end
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local function encodeHeader(o) -- - - - - - - - - - - - - - - encodeHeader
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o = o or {};
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o.id = o.id or dns.random(0, 0xffff); -- 16b (random) id
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o.rd = o.rd or 1; -- 1b 1 recursion desired
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o.tc = o.tc or 0; -- 1b 1 truncated response
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o.aa = o.aa or 0; -- 1b 1 authoritative response
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o.opcode = o.opcode or 0; -- 4b 0 query
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-- 1 inverse query
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-- 2 server status request
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-- 3-15 reserved
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o.qr = o.qr or 0; -- 1b 0 query, 1 response
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o.rcode = o.rcode or 0; -- 4b 0 no error
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-- 1 format error
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-- 2 server failure
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-- 3 name error
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-- 4 not implemented
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-- 5 refused
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-- 6-15 reserved
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o.z = o.z or 0; -- 3b 0 resvered
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o.ra = o.ra or 0; -- 1b 1 recursion available
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o.qdcount = o.qdcount or 1; -- 16b number of question RRs
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o.ancount = o.ancount or 0; -- 16b number of answers RRs
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o.nscount = o.nscount or 0; -- 16b number of nameservers RRs
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o.arcount = o.arcount or 0; -- 16b number of additional RRs
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-- string.char() rounds, so prevent roundup with -0.4999
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local header = string.char(
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highbyte(o.id), o.id %0x100,
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o.rd + 2*o.tc + 4*o.aa + 8*o.opcode + 128*o.qr,
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o.rcode + 16*o.z + 128*o.ra,
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highbyte(o.qdcount), o.qdcount %0x100,
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highbyte(o.ancount), o.ancount %0x100,
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highbyte(o.nscount), o.nscount %0x100,
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highbyte(o.arcount), o.arcount %0x100
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);
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return header, o.id;
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end
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local function encodeName(name) -- - - - - - - - - - - - - - - - encodeName
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local t = {};
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for part in string.gmatch(name, '[^.]+') do
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append(t, string.char(string.len(part)));
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append(t, part);
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end
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append(t, string.char(0));
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return table.concat(t);
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end
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local function encodeQuestion(qname, qtype, qclass) -- - - - encodeQuestion
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qname = encodeName(qname);
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qtype = dns.typecode[qtype or 'a'];
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qclass = dns.classcode[qclass or 'in'];
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return qname..qtype..qclass;
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end
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function resolver:byte(len) -- - - - - - - - - - - - - - - - - - - - - byte
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len = len or 1;
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local offset = self.offset;
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local last = offset + len - 1;
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if last > #self.packet then
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error(string.format('out of bounds: %i>%i', last, #self.packet));
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end
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self.offset = offset + len;
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return string.byte(self.packet, offset, last);
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end
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function resolver:word() -- - - - - - - - - - - - - - - - - - - - - - word
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local b1, b2 = self:byte(2);
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return 0x100*b1 + b2;
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end
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function resolver:dword () -- - - - - - - - - - - - - - - - - - - - - dword
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local b1, b2, b3, b4 = self:byte(4);
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--print('dword', b1, b2, b3, b4);
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return 0x1000000*b1 + 0x10000*b2 + 0x100*b3 + b4;
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end
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function resolver:sub(len) -- - - - - - - - - - - - - - - - - - - - - - sub
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len = len or 1;
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local s = string.sub(self.packet, self.offset, self.offset + len - 1);
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self.offset = self.offset + len;
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return s;
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end
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function resolver:header(force) -- - - - - - - - - - - - - - - - - - header
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local id = self:word();
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--print(string.format(':header id %x', id));
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if not self.active[id] and not force then return nil; end
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local h = { id = id };
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local b1, b2 = self:byte(2);
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h.rd = b1 %2;
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h.tc = b1 /2%2;
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h.aa = b1 /4%2;
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h.opcode = b1 /8%16;
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h.qr = b1 /128;
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h.rcode = b2 %16;
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h.z = b2 /16%8;
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h.ra = b2 /128;
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h.qdcount = self:word();
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h.ancount = self:word();
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h.nscount = self:word();
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h.arcount = self:word();
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for k,v in pairs(h) do h[k] = v-v%1; end
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return h;
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end
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function resolver:name() -- - - - - - - - - - - - - - - - - - - - - - name
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local remember, pointers = nil, 0;
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local len = self:byte();
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local n = {};
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if len == 0 then return "." end -- Root label
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while len > 0 do
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if len >= 0xc0 then -- name is "compressed"
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pointers = pointers + 1;
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if pointers >= 20 then error('dns error: 20 pointers'); end;
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local offset = ((len-0xc0)*0x100) + self:byte();
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remember = remember or self.offset;
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self.offset = offset + 1; -- +1 for lua
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else -- name is not compressed
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append(n, self:sub(len)..'.');
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end
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len = self:byte();
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end
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self.offset = remember or self.offset;
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return table.concat(n);
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end
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function resolver:question() -- - - - - - - - - - - - - - - - - - question
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local q = {};
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q.name = self:name();
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q.type = dns.type[self:word()];
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q.class = dns.class[self:word()];
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return q;
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end
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function resolver:A(rr) -- - - - - - - - - - - - - - - - - - - - - - - - A
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local b1, b2, b3, b4 = self:byte(4);
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rr.a = string.format('%i.%i.%i.%i', b1, b2, b3, b4);
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end
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function resolver:AAAA(rr)
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local addr = {};
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for i = 1, rr.rdlength, 2 do
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local b1, b2 = self:byte(2);
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table.insert(addr, ("%02x%02x"):format(b1, b2));
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end
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addr = table.concat(addr, ":"):gsub("%f[%x]0+(%x)","%1");
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local zeros = {};
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for item in addr:gmatch(":[0:]+:") do
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table.insert(zeros, item)
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end
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if #zeros == 0 then
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rr.aaaa = addr;
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return
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elseif #zeros > 1 then
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table.sort(zeros, function(a, b) return #a > #b end);
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end
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rr.aaaa = addr:gsub(zeros[1], "::", 1):gsub("^0::", "::"):gsub("::0$", "::");
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end
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function resolver:CNAME(rr) -- - - - - - - - - - - - - - - - - - - - CNAME
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rr.cname = self:name();
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end
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function resolver:MX(rr) -- - - - - - - - - - - - - - - - - - - - - - - MX
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rr.pref = self:word();
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rr.mx = self:name();
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end
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function resolver:LOC_nibble_power() -- - - - - - - - - - LOC_nibble_power
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local b = self:byte();
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--print('nibbles', ((b-(b%0x10))/0x10), (b%0x10));
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return ((b-(b%0x10))/0x10) * (10^(b%0x10));
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end
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function resolver:LOC(rr) -- - - - - - - - - - - - - - - - - - - - - - LOC
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rr.version = self:byte();
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if rr.version == 0 then
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rr.loc = rr.loc or {};
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rr.loc.size = self:LOC_nibble_power();
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rr.loc.horiz_pre = self:LOC_nibble_power();
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rr.loc.vert_pre = self:LOC_nibble_power();
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rr.loc.latitude = self:dword();
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rr.loc.longitude = self:dword();
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rr.loc.altitude = self:dword();
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end
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end
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local function LOC_tostring_degrees(f, pos, neg) -- - - - - - - - - - - - -
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f = f - 0x80000000;
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if f < 0 then pos = neg; f = -f; end
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local deg, min, msec;
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msec = f%60000;
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f = (f-msec)/60000;
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min = f%60;
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deg = (f-min)/60;
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return string.format('%3d %2d %2.3f %s', deg, min, msec/1000, pos);
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end
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function resolver.LOC_tostring(rr) -- - - - - - - - - - - - - LOC_tostring
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local t = {};
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--[[
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for k,name in pairs { 'size', 'horiz_pre', 'vert_pre', 'latitude', 'longitude', 'altitude' } do
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append(t, string.format('%4s%-10s: %12.0f\n', '', name, rr.loc[name]));
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end
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--]]
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append(t, string.format(
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'%s %s %.2fm %.2fm %.2fm %.2fm',
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LOC_tostring_degrees (rr.loc.latitude, 'N', 'S'),
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LOC_tostring_degrees (rr.loc.longitude, 'E', 'W'),
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(rr.loc.altitude - 10000000) / 100,
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rr.loc.size / 100,
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rr.loc.horiz_pre / 100,
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rr.loc.vert_pre / 100
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));
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return table.concat(t);
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end
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function resolver:NS(rr) -- - - - - - - - - - - - - - - - - - - - - - - NS
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rr.ns = self:name();
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end
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function resolver:SOA(rr) -- - - - - - - - - - - - - - - - - - - - - - SOA
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end
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function resolver:SRV(rr) -- - - - - - - - - - - - - - - - - - - - - - SRV
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rr.srv = {};
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rr.srv.priority = self:word();
|
|
rr.srv.weight = self:word();
|
|
rr.srv.port = self:word();
|
|
rr.srv.target = self:name();
|
|
end
|
|
|
|
function resolver:PTR(rr)
|
|
rr.ptr = self:name();
|
|
end
|
|
|
|
function resolver:TXT(rr) -- - - - - - - - - - - - - - - - - - - - - - TXT
|
|
rr.txt = self:sub (self:byte());
|
|
end
|
|
|
|
|
|
function resolver:rr() -- - - - - - - - - - - - - - - - - - - - - - - - rr
|
|
local rr = {};
|
|
setmetatable(rr, rr_metatable);
|
|
rr.name = self:name(self);
|
|
rr.type = dns.type[self:word()] or rr.type;
|
|
rr.class = dns.class[self:word()] or rr.class;
|
|
rr.ttl = 0x10000*self:word() + self:word();
|
|
rr.rdlength = self:word();
|
|
|
|
if rr.ttl <= 0 then
|
|
rr.tod = self.time + 30;
|
|
else
|
|
rr.tod = self.time + rr.ttl;
|
|
end
|
|
|
|
local remember = self.offset;
|
|
local rr_parser = self[dns.type[rr.type]];
|
|
if rr_parser then rr_parser(self, rr); end
|
|
self.offset = remember;
|
|
rr.rdata = self:sub(rr.rdlength);
|
|
return rr;
|
|
end
|
|
|
|
|
|
function resolver:rrs (count) -- - - - - - - - - - - - - - - - - - - - - rrs
|
|
local rrs = {};
|
|
for i = 1,count do append(rrs, self:rr()); end
|
|
return rrs;
|
|
end
|
|
|
|
|
|
function resolver:decode(packet, force) -- - - - - - - - - - - - - - decode
|
|
self.packet, self.offset = packet, 1;
|
|
local header = self:header(force);
|
|
if not header then return nil; end
|
|
local response = { header = header };
|
|
|
|
response.question = {};
|
|
local offset = self.offset;
|
|
for i = 1,response.header.qdcount do
|
|
append(response.question, self:question());
|
|
end
|
|
response.question.raw = string.sub(self.packet, offset, self.offset - 1);
|
|
|
|
if not force then
|
|
if not self.active[response.header.id] or not self.active[response.header.id][response.question.raw] then
|
|
self.active[response.header.id] = nil;
|
|
return nil;
|
|
end
|
|
end
|
|
|
|
response.answer = self:rrs(response.header.ancount);
|
|
response.authority = self:rrs(response.header.nscount);
|
|
response.additional = self:rrs(response.header.arcount);
|
|
|
|
return response;
|
|
end
|
|
|
|
|
|
-- socket layer -------------------------------------------------- socket layer
|
|
|
|
|
|
resolver.delays = { 1, 3 };
|
|
|
|
|
|
function resolver:addnameserver(address) -- - - - - - - - - - addnameserver
|
|
self.server = self.server or {};
|
|
append(self.server, address);
|
|
end
|
|
|
|
|
|
function resolver:setnameserver(address) -- - - - - - - - - - setnameserver
|
|
self.server = {};
|
|
self:addnameserver(address);
|
|
end
|
|
|
|
|
|
function resolver:adddefaultnameservers() -- - - - - adddefaultnameservers
|
|
if is_windows then
|
|
if windows and windows.get_nameservers then
|
|
for _, server in ipairs(windows.get_nameservers()) do
|
|
self:addnameserver(server);
|
|
end
|
|
end
|
|
if not self.server or #self.server == 0 then
|
|
-- TODO log warning about no nameservers, adding opendns servers as fallback
|
|
self:addnameserver("208.67.222.222");
|
|
self:addnameserver("208.67.220.220");
|
|
end
|
|
else -- posix
|
|
local resolv_conf = io.open("/etc/resolv.conf");
|
|
if resolv_conf then
|
|
for line in resolv_conf:lines() do
|
|
line = line:gsub("#.*$", "")
|
|
:match('^%s*nameserver%s+(.*)%s*$');
|
|
if line then
|
|
line:gsub("%f[%d.](%d+%.%d+%.%d+%.%d+)%f[^%d.]", function (address)
|
|
self:addnameserver(address)
|
|
end);
|
|
end
|
|
end
|
|
end
|
|
if not self.server or #self.server == 0 then
|
|
-- TODO log warning about no nameservers, adding localhost as the default nameserver
|
|
self:addnameserver("127.0.0.1");
|
|
end
|
|
end
|
|
end
|
|
|
|
|
|
function resolver:getsocket(servernum) -- - - - - - - - - - - - - getsocket
|
|
self.socket = self.socket or {};
|
|
self.socketset = self.socketset or {};
|
|
|
|
local sock = self.socket[servernum];
|
|
if sock then return sock; end
|
|
|
|
local ok, err;
|
|
sock, err = socket.udp();
|
|
if sock and self.socket_wrapper then sock, err = self.socket_wrapper(sock, self); end
|
|
if not sock then
|
|
return nil, err;
|
|
end
|
|
sock:settimeout(0);
|
|
-- todo: attempt to use a random port, fallback to 0
|
|
self.socket[servernum] = sock;
|
|
self.socketset[sock] = servernum;
|
|
-- set{sock,peer}name can fail, eg because of local routing table
|
|
-- if so, try the next server
|
|
ok, err = sock:setsockname('*', 0);
|
|
if not ok then return self:servfail(sock, err); end
|
|
ok, err = sock:setpeername(self.server[servernum], 53);
|
|
if not ok then return self:servfail(sock, err); end
|
|
return sock;
|
|
end
|
|
|
|
function resolver:voidsocket(sock)
|
|
if self.socket[sock] then
|
|
self.socketset[self.socket[sock]] = nil;
|
|
self.socket[sock] = nil;
|
|
elseif self.socketset[sock] then
|
|
self.socket[self.socketset[sock]] = nil;
|
|
self.socketset[sock] = nil;
|
|
end
|
|
sock:close();
|
|
end
|
|
|
|
function resolver:socket_wrapper_set(func) -- - - - - - - socket_wrapper_set
|
|
self.socket_wrapper = func;
|
|
end
|
|
|
|
|
|
function resolver:closeall () -- - - - - - - - - - - - - - - - - - closeall
|
|
for i,sock in ipairs(self.socket) do
|
|
self.socket[i] = nil;
|
|
self.socketset[sock] = nil;
|
|
sock:close();
|
|
end
|
|
end
|
|
|
|
|
|
function resolver:remember(rr, type) -- - - - - - - - - - - - - - remember
|
|
--print ('remember', type, rr.class, rr.type, rr.name)
|
|
local qname, qtype, qclass = standardize(rr.name, rr.type, rr.class);
|
|
|
|
if type ~= '*' then
|
|
type = qtype;
|
|
local all = get(self.cache, qclass, '*', qname);
|
|
--print('remember all', all);
|
|
if all then append(all, rr); end
|
|
end
|
|
|
|
self.cache = self.cache or setmetatable({}, cache_metatable);
|
|
local rrs = get(self.cache, qclass, type, qname) or
|
|
set(self.cache, qclass, type, qname, setmetatable({}, rrs_metatable));
|
|
if not rrs[rr[qtype:lower()]] then
|
|
rrs[rr[qtype:lower()]] = true;
|
|
append(rrs, rr);
|
|
end
|
|
|
|
if type == 'MX' then self.unsorted[rrs] = true; end
|
|
end
|
|
|
|
|
|
local function comp_mx(a, b) -- - - - - - - - - - - - - - - - - - - comp_mx
|
|
return (a.pref == b.pref) and (a.mx < b.mx) or (a.pref < b.pref);
|
|
end
|
|
|
|
|
|
function resolver:peek (qname, qtype, qclass, n) -- - - - - - - - - - - - peek
|
|
qname, qtype, qclass = standardize(qname, qtype, qclass);
|
|
local rrs = get(self.cache, qclass, qtype, qname);
|
|
if not rrs then
|
|
if n then if n <= 0 then return end else n = 3 end
|
|
rrs = get(self.cache, qclass, "CNAME", qname);
|
|
if not (rrs and rrs[1]) then return end
|
|
return self:peek(rrs[1].cname, qtype, qclass, n - 1);
|
|
end
|
|
if prune(rrs, socket.gettime()) and qtype == '*' or not next(rrs) then
|
|
set(self.cache, qclass, qtype, qname, nil);
|
|
return nil;
|
|
end
|
|
if self.unsorted[rrs] then table.sort (rrs, comp_mx); self.unsorted[rrs] = nil; end
|
|
return rrs;
|
|
end
|
|
|
|
|
|
function resolver:purge(soft) -- - - - - - - - - - - - - - - - - - - purge
|
|
if soft == 'soft' then
|
|
self.time = socket.gettime();
|
|
for class,types in pairs(self.cache or {}) do
|
|
for type,names in pairs(types) do
|
|
for name,rrs in pairs(names) do
|
|
prune(rrs, self.time, 'soft')
|
|
end
|
|
end
|
|
end
|
|
else self.cache = setmetatable({}, cache_metatable); end
|
|
end
|
|
|
|
|
|
function resolver:query(qname, qtype, qclass) -- - - - - - - - - - -- query
|
|
qname, qtype, qclass = standardize(qname, qtype, qclass)
|
|
|
|
local co = coroutine.running();
|
|
local q = get(self.wanted, qclass, qtype, qname);
|
|
if co and q then
|
|
-- We are already waiting for a reply to an identical query.
|
|
set(self.wanted, qclass, qtype, qname, co, true);
|
|
return true;
|
|
end
|
|
|
|
if not self.server then self:adddefaultnameservers(); end
|
|
|
|
local question = encodeQuestion(qname, qtype, qclass);
|
|
local peek = self:peek (qname, qtype, qclass);
|
|
if peek then return peek; end
|
|
|
|
local header, id = encodeHeader();
|
|
--print ('query id', id, qclass, qtype, qname)
|
|
local o = {
|
|
packet = header..question,
|
|
server = self.best_server,
|
|
delay = 1,
|
|
retry = socket.gettime() + self.delays[1]
|
|
};
|
|
|
|
-- remember the query
|
|
self.active[id] = self.active[id] or {};
|
|
self.active[id][question] = o;
|
|
|
|
-- remember which coroutine wants the answer
|
|
if co then
|
|
set(self.wanted, qclass, qtype, qname, co, true);
|
|
end
|
|
|
|
local conn, err = self:getsocket(o.server)
|
|
if not conn then
|
|
return nil, err;
|
|
end
|
|
conn:send (o.packet)
|
|
|
|
if timer and self.timeout then
|
|
local num_servers = #self.server;
|
|
local i = 1;
|
|
timer.add_task(self.timeout, function ()
|
|
if get(self.wanted, qclass, qtype, qname, co) then
|
|
if i < num_servers then
|
|
i = i + 1;
|
|
self:servfail(conn);
|
|
o.server = self.best_server;
|
|
conn, err = self:getsocket(o.server);
|
|
if conn then
|
|
conn:send(o.packet);
|
|
return self.timeout;
|
|
end
|
|
end
|
|
-- Tried everything, failed
|
|
self:cancel(qclass, qtype, qname);
|
|
end
|
|
end)
|
|
end
|
|
return true;
|
|
end
|
|
|
|
function resolver:servfail(sock, err)
|
|
-- Resend all queries for this server
|
|
|
|
local num = self.socketset[sock]
|
|
|
|
-- Socket is dead now
|
|
sock = self:voidsocket(sock);
|
|
|
|
-- Find all requests to the down server, and retry on the next server
|
|
self.time = socket.gettime();
|
|
for id,queries in pairs(self.active) do
|
|
for question,o in pairs(queries) do
|
|
if o.server == num then -- This request was to the broken server
|
|
o.server = o.server + 1 -- Use next server
|
|
if o.server > #self.server then
|
|
o.server = 1;
|
|
end
|
|
|
|
o.retries = (o.retries or 0) + 1;
|
|
if o.retries >= #self.server then
|
|
--print('timeout');
|
|
queries[question] = nil;
|
|
else
|
|
sock, err = self:getsocket(o.server);
|
|
if sock then sock:send(o.packet); end
|
|
end
|
|
end
|
|
end
|
|
if next(queries) == nil then
|
|
self.active[id] = nil;
|
|
end
|
|
end
|
|
|
|
if num == self.best_server then
|
|
self.best_server = self.best_server + 1;
|
|
if self.best_server > #self.server then
|
|
-- Exhausted all servers, try first again
|
|
self.best_server = 1;
|
|
end
|
|
end
|
|
return sock, err;
|
|
end
|
|
|
|
function resolver:settimeout(seconds)
|
|
self.timeout = seconds;
|
|
end
|
|
|
|
function resolver:receive(rset) -- - - - - - - - - - - - - - - - - receive
|
|
--print('receive'); print(self.socket);
|
|
self.time = socket.gettime();
|
|
rset = rset or self.socket;
|
|
|
|
local response;
|
|
for i,sock in pairs(rset) do
|
|
|
|
if self.socketset[sock] then
|
|
local packet = sock:receive();
|
|
if packet then
|
|
response = self:decode(packet);
|
|
if response and self.active[response.header.id]
|
|
and self.active[response.header.id][response.question.raw] then
|
|
--print('received response');
|
|
--self.print(response);
|
|
|
|
for j,rr in pairs(response.answer) do
|
|
self:remember(rr, response.question[1].type)
|
|
end
|
|
|
|
-- retire the query
|
|
local queries = self.active[response.header.id];
|
|
queries[response.question.raw] = nil;
|
|
|
|
if not next(queries) then self.active[response.header.id] = nil; end
|
|
if not next(self.active) then self:closeall(); end
|
|
|
|
-- was the query on the wanted list?
|
|
local q = response.question[1];
|
|
local cos = get(self.wanted, q.class, q.type, q.name);
|
|
if cos then
|
|
for co in pairs(cos) do
|
|
if coroutine.status(co) == "suspended" then coroutine.resume(co); end
|
|
end
|
|
set(self.wanted, q.class, q.type, q.name, nil);
|
|
end
|
|
end
|
|
|
|
end
|
|
end
|
|
end
|
|
|
|
return response;
|
|
end
|
|
|
|
|
|
function resolver:feed(sock, packet, force)
|
|
--print('receive'); print(self.socket);
|
|
self.time = socket.gettime();
|
|
|
|
local response = self:decode(packet, force);
|
|
if response and self.active[response.header.id]
|
|
and self.active[response.header.id][response.question.raw] then
|
|
--print('received response');
|
|
--self.print(response);
|
|
|
|
for j,rr in pairs(response.answer) do
|
|
self:remember(rr, response.question[1].type);
|
|
end
|
|
|
|
-- retire the query
|
|
local queries = self.active[response.header.id];
|
|
queries[response.question.raw] = nil;
|
|
if not next(queries) then self.active[response.header.id] = nil; end
|
|
if not next(self.active) then self:closeall(); end
|
|
|
|
-- was the query on the wanted list?
|
|
local q = response.question[1];
|
|
if q then
|
|
local cos = get(self.wanted, q.class, q.type, q.name);
|
|
if cos then
|
|
for co in pairs(cos) do
|
|
if coroutine.status(co) == "suspended" then coroutine.resume(co); end
|
|
end
|
|
set(self.wanted, q.class, q.type, q.name, nil);
|
|
end
|
|
end
|
|
end
|
|
|
|
return response;
|
|
end
|
|
|
|
function resolver:cancel(qclass, qtype, qname)
|
|
local cos = get(self.wanted, qclass, qtype, qname);
|
|
if cos then
|
|
for co in pairs(cos) do
|
|
if coroutine.status(co) == "suspended" then coroutine.resume(co); end
|
|
end
|
|
set(self.wanted, qclass, qtype, qname, nil);
|
|
end
|
|
end
|
|
|
|
function resolver:pulse() -- - - - - - - - - - - - - - - - - - - - - pulse
|
|
--print(':pulse');
|
|
while self:receive() do end
|
|
if not next(self.active) then return nil; end
|
|
|
|
self.time = socket.gettime();
|
|
for id,queries in pairs(self.active) do
|
|
for question,o in pairs(queries) do
|
|
if self.time >= o.retry then
|
|
|
|
o.server = o.server + 1;
|
|
if o.server > #self.server then
|
|
o.server = 1;
|
|
o.delay = o.delay + 1;
|
|
end
|
|
|
|
if o.delay > #self.delays then
|
|
--print('timeout');
|
|
queries[question] = nil;
|
|
if not next(queries) then self.active[id] = nil; end
|
|
if not next(self.active) then return nil; end
|
|
else
|
|
--print('retry', o.server, o.delay);
|
|
local _a = self.socket[o.server];
|
|
if _a then _a:send(o.packet); end
|
|
o.retry = self.time + self.delays[o.delay];
|
|
end
|
|
end
|
|
end
|
|
end
|
|
|
|
if next(self.active) then return true; end
|
|
return nil;
|
|
end
|
|
|
|
|
|
function resolver:lookup(qname, qtype, qclass) -- - - - - - - - - - lookup
|
|
self:query (qname, qtype, qclass)
|
|
while self:pulse() do
|
|
local recvt = {}
|
|
for i, s in ipairs(self.socket) do
|
|
recvt[i] = s
|
|
end
|
|
socket.select(recvt, nil, 4)
|
|
end
|
|
--print(self.cache);
|
|
return self:peek(qname, qtype, qclass);
|
|
end
|
|
|
|
function resolver:lookupex(handler, qname, qtype, qclass) -- - - - - - - - - - lookup
|
|
return self:peek(qname, qtype, qclass) or self:query(qname, qtype, qclass);
|
|
end
|
|
|
|
function resolver:tohostname(ip)
|
|
return dns.lookup(ip:gsub("(%d+)%.(%d+)%.(%d+)%.(%d+)", "%4.%3.%2.%1.in-addr.arpa."), "PTR");
|
|
end
|
|
|
|
--print ---------------------------------------------------------------- print
|
|
|
|
|
|
local hints = { -- - - - - - - - - - - - - - - - - - - - - - - - - - - hints
|
|
qr = { [0]='query', 'response' },
|
|
opcode = { [0]='query', 'inverse query', 'server status request' },
|
|
aa = { [0]='non-authoritative', 'authoritative' },
|
|
tc = { [0]='complete', 'truncated' },
|
|
rd = { [0]='recursion not desired', 'recursion desired' },
|
|
ra = { [0]='recursion not available', 'recursion available' },
|
|
z = { [0]='(reserved)' },
|
|
rcode = { [0]='no error', 'format error', 'server failure', 'name error', 'not implemented' },
|
|
|
|
type = dns.type,
|
|
class = dns.class
|
|
};
|
|
|
|
|
|
local function hint(p, s) -- - - - - - - - - - - - - - - - - - - - - - hint
|
|
return (hints[s] and hints[s][p[s]]) or '';
|
|
end
|
|
|
|
|
|
function resolver.print(response) -- - - - - - - - - - - - - resolver.print
|
|
for s,s in pairs { 'id', 'qr', 'opcode', 'aa', 'tc', 'rd', 'ra', 'z',
|
|
'rcode', 'qdcount', 'ancount', 'nscount', 'arcount' } do
|
|
print( string.format('%-30s', 'header.'..s), response.header[s], hint(response.header, s) );
|
|
end
|
|
|
|
for i,question in ipairs(response.question) do
|
|
print(string.format ('question[%i].name ', i), question.name);
|
|
print(string.format ('question[%i].type ', i), question.type);
|
|
print(string.format ('question[%i].class ', i), question.class);
|
|
end
|
|
|
|
local common = { name=1, type=1, class=1, ttl=1, rdlength=1, rdata=1 };
|
|
local tmp;
|
|
for s,s in pairs({'answer', 'authority', 'additional'}) do
|
|
for i,rr in pairs(response[s]) do
|
|
for j,t in pairs({ 'name', 'type', 'class', 'ttl', 'rdlength' }) do
|
|
tmp = string.format('%s[%i].%s', s, i, t);
|
|
print(string.format('%-30s', tmp), rr[t], hint(rr, t));
|
|
end
|
|
for j,t in pairs(rr) do
|
|
if not common[j] then
|
|
tmp = string.format('%s[%i].%s', s, i, j);
|
|
print(string.format('%-30s %s', tostring(tmp), tostring(t)));
|
|
end
|
|
end
|
|
end
|
|
end
|
|
end
|
|
|
|
|
|
-- module api ------------------------------------------------------ module api
|
|
|
|
|
|
function dns.resolver () -- - - - - - - - - - - - - - - - - - - - - resolver
|
|
-- this function seems to be redundant with resolver.new ()
|
|
|
|
local r = { active = {}, cache = {}, unsorted = {}, wanted = {}, best_server = 1 };
|
|
setmetatable (r, resolver);
|
|
setmetatable (r.cache, cache_metatable);
|
|
setmetatable (r.unsorted, { __mode = 'kv' });
|
|
return r;
|
|
end
|
|
|
|
local _resolver = dns.resolver();
|
|
dns._resolver = _resolver;
|
|
|
|
function dns.lookup(...) -- - - - - - - - - - - - - - - - - - - - - lookup
|
|
return _resolver:lookup(...);
|
|
end
|
|
|
|
function dns.tohostname(...)
|
|
return _resolver:tohostname(...);
|
|
end
|
|
|
|
function dns.purge(...) -- - - - - - - - - - - - - - - - - - - - - - purge
|
|
return _resolver:purge(...);
|
|
end
|
|
|
|
function dns.peek(...) -- - - - - - - - - - - - - - - - - - - - - - - peek
|
|
return _resolver:peek(...);
|
|
end
|
|
|
|
function dns.query(...) -- - - - - - - - - - - - - - - - - - - - - - query
|
|
return _resolver:query(...);
|
|
end
|
|
|
|
function dns.feed(...) -- - - - - - - - - - - - - - - - - - - - - - - feed
|
|
return _resolver:feed(...);
|
|
end
|
|
|
|
function dns.cancel(...) -- - - - - - - - - - - - - - - - - - - - - - cancel
|
|
return _resolver:cancel(...);
|
|
end
|
|
|
|
function dns.settimeout(...)
|
|
return _resolver:settimeout(...);
|
|
end
|
|
|
|
function dns.cache()
|
|
return _resolver.cache;
|
|
end
|
|
|
|
function dns.socket_wrapper_set(...) -- - - - - - - - - socket_wrapper_set
|
|
return _resolver:socket_wrapper_set(...);
|
|
end
|
|
|
|
return dns;
|