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-- libunbound based net.adns replacement for Prosody IM
-- Copyright (C) 2012-2015 Kim Alvefur
-- Copyright (C) 2012 Waqas Hussain
--
-- This file is MIT licensed.
local setmetatable = setmetatable;
local table = table;
local t_concat = table.concat;
local t_insert = table.insert;
local s_byte = string.byte;
local s_char = string.char;
local s_format = string.format;
local s_gsub = string.gsub;
local s_sub = string.sub;
local s_match = string.match;
local s_gmatch = string.gmatch;
local have_net, net_util = pcall(require, "util.net");
local iana_data = require "util.dnsregistry";
if have_net and not net_util.ntop then -- Added in Prosody 0.11
have_net = false;
end
local chartohex = {};
for c = 0, 255 do
chartohex[s_char(c)] = s_format("%02X", c);
end
local function tohex(s)
return (s_gsub(s, ".", chartohex));
end
-- Simplified versions of Waqas DNS parsers
-- Only the per RR parsers are needed and only feed a single RR
local parsers = {};
-- No support for pointers, but libunbound appears to take care of that.
local function readDnsName(packet, pos)
if s_byte(packet, pos) == 0 then return "."; end
local pack_len, r, len = #packet, {};
pos = pos or 1;
repeat
len = s_byte(packet, pos) or 0;
t_insert(r, s_sub(packet, pos + 1, pos + len));
pos = pos + len + 1;
until len == 0 or pos >= pack_len;
return t_concat(r, "."), pos;
end
-- These are just simple names.
parsers.CNAME = readDnsName;
parsers.NS = readDnsName
parsers.PTR = readDnsName;
local soa_mt = {
__tostring = function(rr)
return s_format("%s %s %d %d %d %d %d", rr.mname, rr.rname, rr.serial, rr.refresh, rr.retry, rr.expire, rr.minimum);
end;
};
function parsers.SOA(packet)
local mname, rname, offset;
mname, offset = readDnsName(packet, 1);
rname, offset = readDnsName(packet, offset);
-- Extract all the bytes of these fields in one call
local
s1, s2, s3, s4, -- serial
r1, r2, r3, r4, -- refresh
t1, t2, t3, t4, -- retry
e1, e2, e3, e4, -- expire
m1, m2, m3, m4 -- minimum
= s_byte(packet, offset, offset + 19);
return setmetatable({
mname = mname;
rname = rname;
serial = s1*0x1000000 + s2*0x10000 + s3*0x100 + s4;
refresh = r1*0x1000000 + r2*0x10000 + r3*0x100 + r4;
retry = t1*0x1000000 + t2*0x10000 + t3*0x100 + t4;
expire = e1*0x1000000 + e2*0x10000 + e3*0x100 + e4;
minimum = m1*0x1000000 + m2*0x10000 + m3*0x100 + m4;
}, soa_mt);
end
function parsers.A(packet)
return s_format("%d.%d.%d.%d", s_byte(packet, 1, 4));
end
local aaaa = { nil, nil, nil, nil, nil, nil, nil, nil, };
function parsers.AAAA(packet)
local hi, lo, ip, len, token;
for i = 1, 8 do
hi, lo = s_byte(packet, i * 2 - 1, i * 2);
aaaa[i] = s_format("%x", hi * 256 + lo); -- skips leading zeros
end
ip = t_concat(aaaa, ":", 1, 8);
len = (s_match(ip, "^0:[0:]+()") or 1) - 1;
for s in s_gmatch(ip, ":0:[0:]+") do
if len < #s then len, token = #s, s; end -- find longest sequence of zeros
end
return (s_gsub(ip, token or "^0:[0:]+", "::", 1));
end
if have_net then
parsers.A = net_util.ntop;
parsers.AAAA = net_util.ntop;
end
local mx_mt = {
__tostring = function(rr)
return s_format("%d %s", rr.pref, rr.mx)
end
};
function parsers.MX(packet)
local name = readDnsName(packet, 3);
local b1,b2 = s_byte(packet, 1, 2);
return setmetatable({
pref = b1*256+b2;
mx = name;
}, mx_mt);
end
local srv_mt = {
__tostring = function(rr)
return s_format("%d %d %d %s", rr.priority, rr.weight, rr.port, rr.target);
end
};
function parsers.SRV(packet)
local name = readDnsName(packet, 7);
local b1, b2, b3, b4, b5, b6 = s_byte(packet, 1, 6);
return setmetatable({
priority = b1*256+b2;
weight = b3*256+b4;
port = b5*256+b6;
target = name;
}, srv_mt);
end
local txt_mt = { __tostring = t_concat };
function parsers.TXT(packet)
local pack_len = #packet;
local r, pos, len = {}, 1;
repeat
len = s_byte(packet, pos) or 0;
t_insert(r, s_sub(packet, pos + 1, pos + len));
pos = pos + len + 1;
until pos >= pack_len;
return setmetatable(r, txt_mt);
end
parsers.SPF = parsers.TXT;
-- Acronyms from RFC 7218
local tlsa_usages = {
[0] = "PKIX-CA";
[1] = "PKIX-EE";
[2] = "DANE-TA";
[3] = "DANE-EE";
[255] = "PrivCert";
};
local tlsa_selectors = {
[0] = "Cert",
[1] = "SPKI",
[255] = "PrivSel",
};
local tlsa_match_types = {
[0] = "Full",
[1] = "SHA2-256",
[2] = "SHA2-512",
[255] = "PrivMatch",
};
local tlsa_mt = {
__tostring = function(rr)
return s_format("%s %s %s %s",
tlsa_usages[rr.use] or rr.use,
tlsa_selectors[rr.select] or rr.select,
tlsa_match_types[rr.match] or rr.match,
tohex(rr.data));
end;
__index = {
getUsage = function(rr) return tlsa_usages[rr.use] end;
getSelector = function(rr) return tlsa_selectors[rr.select] end;
getMatchType = function(rr) return tlsa_match_types[rr.match] end;
}
};
function parsers.TLSA(packet)
local use, select, match = s_byte(packet, 1,3);
return setmetatable({
use = use;
select = select;
match = match;
data = s_sub(packet, 4);
}, tlsa_mt);
end
local params = {
TLSA = {
use = tlsa_usages;
select = tlsa_selectors;
match = tlsa_match_types;
};
};
local fallback_mt = {
__tostring = function(rr)
return s_format([[\# %d %s]], #rr.raw, tohex(rr.raw));
end;
};
local function fallback_parser(packet)
return setmetatable({ raw = packet },fallback_mt);
end
setmetatable(parsers, { __index = function() return fallback_parser end });
return {
parsers = parsers;
classes = iana_data.classes;
types = iana_data.types;
errors = iana_data.errors;
params = params;
};
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