Software /
code /
prosody
File
util/dns.lua @ 10961:f93dce30089a
util.dns: Library for decoding DNS records
Imported from luaunbound-prosody 5f7c771138b1
author | Kim Alvefur <zash@zash.se> |
---|---|
date | Sat, 09 Mar 2019 21:16:27 +0100 |
child | 10972:b3773b1b90a1 |
line wrap: on
line source
-- 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"); 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 -- Converted from -- http://www.iana.org/assignments/dns-parameters -- 2015-05-19 local classes = { IN = 1; "IN"; nil; CH = 3; "CH"; HS = 4; "HS"; }; local types = { "A";"NS";"MD";"MF";"CNAME";"SOA";"MB";"MG";"MR";"NULL";"WKS";"PTR";"HINFO"; "MINFO";"MX";"TXT";"RP";"AFSDB";"X25";"ISDN";"RT";"NSAP";"NSAP-PTR";"SIG"; "KEY";"PX";"GPOS";"AAAA";"LOC";"NXT";"EID";"NIMLOC";"SRV";"ATMA";"NAPTR"; "KX";"CERT";"A6";"DNAME";"SINK";"OPT";"APL";"DS";"SSHFP";"IPSECKEY";"RRSIG"; "NSEC";"DNSKEY";"DHCID";"NSEC3";"NSEC3PARAM";"TLSA";[55]="HIP";[56]="NINFO"; [57]="RKEY";[58]="TALINK";[59]="CDS";[60]="CDNSKEY";[61]="OPENPGPKEY"; [62]="CSYNC";TLSA=52;NS=2;[249]="TKEY";[251]="IXFR";NSAP=22;UID=101;APL=42; MG=8;NIMLOC=32;DHCID=49;TALINK=58;HINFO=13;MINFO=14;EID=31;DS=43;CSYNC=62; RKEY=57;TKEY=249;NID=104;NAPTR=35;RT=21;LP=107;L32=105;KEY=25;MD=3;MX=15; A6=38;KX=36;PX=26;CAA=257;WKS=11;TSIG=250;MAILA=254;CDS=59;SINK=40;LOC=29; DLV=32769;[32769]="DLV";TA=32768;[32768]="TA";GID=102;IXFR=251;MAILB=253; [256]="URI";[250]="TSIG";[252]="AXFR";NSEC=47;HIP=55;[254]="MAILA";[255]="*"; NSEC3PARAM=51;["*"]=255;URI=256;[253]="MAILB";AXFR=252;SPF=99;NXT=30;AFSDB=18; EUI48=108;NINFO=56;CDNSKEY=60;ISDN=20;L64=106;SRV=33;DNSKEY=48;X25=19;TXT=16; RRSIG=46;OPENPGPKEY=61;DNAME=39;CNAME=5;EUI64=109;A=1;MR=9;IPSECKEY=45;OPT=41; UNSPEC=103;["NSAP-PTR"]=23;[103]="UNSPEC";[257]="CAA";UINFO=100;[99]="SPF"; MF=4;[101]="UID";[102]="GID";SOA=6;[104]="NID";[105]="L32";[106]="L64"; [107]="LP";[108]="EUI48";[109]="EUI64";NSEC3=50;RP=17;PTR=12;[100]="UINFO"; NULL=10;AAAA=28;MB=7;GPOS=27;SSHFP=44;CERT=37;SIG=24;ATMA=34 }; local errors = { NoError = "No Error"; [0] = "NoError"; FormErr = "Format Error"; "FormErr"; ServFail = "Server Failure"; "ServFail"; NXDomain = "Non-Existent Domain"; "NXDomain"; NotImp = "Not Implemented"; "NotImp"; Refused = "Query Refused"; "Refused"; YXDomain = "Name Exists when it should not"; "YXDomain"; YXRRSet = "RR Set Exists when it should not"; "YXRRSet"; NXRRSet = "RR Set that should exist does not"; "NXRRSet"; NotAuth = "Server Not Authoritative for zone"; "NotAuth"; NotZone = "Name not contained in zone"; "NotZone"; }; -- 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 = classes; types = types; errors = errors; params = params; };