diff options
| -rw-r--r-- | util/dns.lua | 271 |
1 files changed, 271 insertions, 0 deletions
diff --git a/util/dns.lua b/util/dns.lua new file mode 100644 index 00000000..2a15fbc4 --- /dev/null +++ b/util/dns.lua @@ -0,0 +1,271 @@ +-- 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; +}; |