mirror of
https://github.com/nmap/nmap.git
synced 2025-12-27 18:09:01 +00:00
Consolidate DNS code, fix a few small issues
This commit is contained in:
dmiller
313
nselib/dns.lua
313
nselib/dns.lua
@@ -437,6 +437,31 @@ function reverse(ip)
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return table.concat(ipReverse, ".") .. arpa
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end
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local fetcher = function(typename, callback)
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return function(dec, retAll)
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local answers = {}
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for _, ans in ipairs(dec) do
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if ans.dtype == types[typename] then
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if not retAll then
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return true, callback(ans)
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end
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table.insert(answers, callback(ans))
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end
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end
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if #answers == 0 then
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stdnse.debug2("dns.answerFetcher found no records of the required type: %s", typename)
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return false, "No Answers"
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end
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return true, answers
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end
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end
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local getattr = function(attr)
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return function(obj)
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return obj[attr]
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end
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end
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-- Table for answer fetching functions.
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local answerFetcher = {}
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@@ -447,22 +472,18 @@ local answerFetcher = {}
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-- @return String first dns TXT record or Table of TXT records or String Error message.
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answerFetcher[types.TXT] = function(dec, retAll)
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local answers = {}
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if not retAll and dec.answers[1].data then
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return true, string.sub(dec.answers[1].data, 2)
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elseif not retAll then
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stdnse.debug1("dns.answerFetcher found no records of the required type: TXT")
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return false, "No Answers"
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else
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for _, v in ipairs(dec.answers) do
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if v.TXT and v.TXT.text then
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for _, v in ipairs( v.TXT.text ) do
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table.insert(answers, v)
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for _, v in ipairs(dec) do
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if v.TXT and v.TXT.text then
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for _, v in ipairs( v.TXT.text ) do
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if not retAll then
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return true, v
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end
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table.insert(answers, v)
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end
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end
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end
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if #answers == 0 then
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stdnse.debug1("dns.answerFetcher found no records of the required type: TXT")
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stdnse.debug2("dns.answerFetcher found no records of the required type: TXT")
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return false, "No Answers"
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end
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return true, answers
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@@ -473,47 +494,14 @@ end
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-- @param retAll If true, return all entries, not just the first.
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-- @return True if one or more answers of the required type were found - otherwise false.
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-- @return String first dns A record or Table of A records or String Error message.
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answerFetcher[types.A] = function(dec, retAll)
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local answers = {}
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for _, ans in ipairs(dec.answers) do
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if ans.dtype == types.A then
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if not retAll then
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return true, ans.ip
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end
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table.insert(answers, ans.ip)
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end
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end
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if not retAll or #answers == 0 then
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stdnse.debug1("dns.answerFetcher found no records of the required type: A")
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return false, "No Answers"
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end
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return true, answers
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end
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answerFetcher[types.A] = fetcher("A", getattr("ip"))
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-- Answer fetcher for CNAME records.
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-- @param dec Decoded DNS response.
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-- @param retAll If true, return all entries, not just the first.
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-- @return True if one or more answers of the required type were found - otherwise false.
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-- @return String first Domain entry or Table of domain entries or String Error message.
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answerFetcher[types.CNAME] = function(dec, retAll)
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local answers = {}
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if not retAll and dec.answers[1].domain then
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return true, dec.answers[1].domain
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elseif not retAll then
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stdnse.debug1("dns.answerFetcher found no records of the required type: NS, PTR or CNAME")
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return false, "No Answers"
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else
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for _, v in ipairs(dec.answers) do
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if v.domain then table.insert(answers, v.domain) end
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end
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end
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if #answers == 0 then
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stdnse.debug1("dns.answerFetcher found no records of the required type: NS, PTR or CNAME")
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return false, "No Answers"
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end
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return true, answers
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end
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answerFetcher[types.CNAME] = fetcher("CNAME", getattr("domain"))
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-- Answer fetcher for MX records.
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-- @param dec Decoded DNS response.
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@@ -522,32 +510,9 @@ end
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-- @return String first dns MX record or Table of MX records or String Error message.
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-- Note that the format of a returned MX answer is "preference:hostname:IPaddress" where zero
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-- or more IP addresses may be present.
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answerFetcher[types.MX] = function(dec, retAll)
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local mx, ip, answers = {}, {}, {}
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for _, ans in ipairs(dec.answers) do
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if ans.MX then mx[#mx+1] = ans.MX end
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if not retAll then break end
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end
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if #mx == 0 then
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stdnse.debug1("dns.answerFetcher found no records of the required type: MX")
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return false, "No Answers"
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end
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for _, add in ipairs(dec.add) do
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if ip[add.dname] then table.insert(ip[add.dname], add.ip)
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else ip[add.dname] = {add.ip} end
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end
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for _, mxrec in ipairs(mx) do
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if ip[mxrec.server] then
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table.insert( answers, ("%s:%s:%s"):format(mxrec.pref or "-", mxrec.server or "-", table.concat(ip[mxrec.server], ":")) )
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if not retAll then return true, answers[1] end
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else
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-- no IP ?
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table.insert( answers, ("%s:%s"):format(mxrec.pref or "-", mxrec.server or "-") )
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if not retAll then return true, answers[1] end
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end
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end
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return true, answers
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end
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answerFetcher[types.MX] = fetcher("MX", function(ans)
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return ("%s:%s"):format(ans.pref, ans.server)
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end)
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-- Answer fetcher for SRV records.
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-- @param dec Decoded DNS response.
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@@ -556,23 +521,9 @@ end
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-- @return String first dns SRV record or Table of SRV records or String Error message.
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-- Note that the format of a returned SRV answer is "priority:weight:port:target" where zero
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-- or more IP addresses may be present.
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answerFetcher[types.SRV] = function(dec, retAll)
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local srv, ip, answers = {}, {}, {}
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for _, ans in ipairs(dec.answers) do
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if ans.dtype == types.SRV then
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if not retAll then
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return true, ("%s:%s:%s:%s"):format( ans.SRV.prio, ans.SRV.weight, ans.SRV.port, ans.SRV.target )
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end
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table.insert( answers, ("%s:%s:%s:%s"):format( ans.SRV.prio, ans.SRV.weight, ans.SRV.port, ans.SRV.target ) )
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end
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end
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if #answers == 0 then
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stdnse.debug1("dns.answerFetcher found no records of the required type: SRV")
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return false, "No Answers"
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end
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return true, answers
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end
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answerFetcher[types.SRV] = fetcher("SRV", function(ans)
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return ("%s:%s:%s:%s"):format( ans.SRV.prio, ans.SRV.weight, ans.SRV.port, ans.SRV.target )
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end)
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-- Answer fetcher for NSEC records.
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-- @param dec Decoded DNS response.
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@@ -580,22 +531,9 @@ end
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-- @return True if one or more answers of the required type were found - otherwise false.
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-- @return String first dns NSEC record or Table of NSEC records or String Error message.
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-- Note that the format of a returned NSEC answer is "name:dname:types".
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answerFetcher[types.NSEC] = function(dec, retAll)
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local nsec, answers = {}, {}
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for _, auth in ipairs(dec.auth) do
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if auth.NSEC then nsec[#nsec+1] = auth.NSEC end
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if not retAll then break end
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end
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if #nsec == 0 then
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stdnse.debug1("dns.answerFetcher found no records of the required type: NSEC")
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return false, "No Answers"
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end
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for _, nsecrec in ipairs(nsec) do
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table.insert( answers, ("%s:%s:%s"):format(nsecrec.name or "-", nsecrec.dname or "-", table.concat(nsecrec.types, ":") or "-"))
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end
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if not retAll then return true, answers[1] end
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return true, answers
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end
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answerFetcher[types.NSEC] = fetcher("NSEC", function(ans)
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return ("%s:%s:%s"):format(ans.name or "-", ans.dname or "-", table.concat(ans.types, ":") or "-")
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end)
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-- Answer fetcher for NS records.
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-- @name answerFetcher[types.NS]
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@@ -603,7 +541,7 @@ end
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-- @param dec Decoded DNS response.
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-- @return True if one or more answers of the required type were found - otherwise false.
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-- @return String first Domain entry or Table of domain entries or String Error message.
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answerFetcher[types.NS] = answerFetcher[types.CNAME]
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answerFetcher[types.NS] = fetcher("NS", getattr("domain"))
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-- Answer fetcher for PTR records.
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-- @name answerFetcher[types.PTR]
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@@ -612,31 +550,30 @@ answerFetcher[types.NS] = answerFetcher[types.CNAME]
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-- @param retAll If true, return all entries, not just the first.
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-- @return True if one or more answers of the required type were found - otherwise false.
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-- @return String first Domain entry or Table of domain entries or String Error message.
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answerFetcher[types.PTR] = answerFetcher[types.CNAME]
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answerFetcher[types.PTR] = fetcher("PTR", getattr("domain"))
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-- Answer fetcher for AAAA records.
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-- @param dec Decoded DNS response.
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-- @param retAll If true, return all entries, not just the first.
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-- @return True if one or more answers of the required type were found - otherwise false.
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-- @return String first dns AAAA record or Table of AAAA records or String Error message.
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answerFetcher[types.AAAA] = function(dec, retAll)
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local answers = {}
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for _, ans in ipairs(dec.answers) do
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if ans.dtype == types.AAAA then
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if not retAll then
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return true, ans.ipv6
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end
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table.insert(answers, ans.ipv6)
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answerFetcher[types.AAAA] = fetcher("AAAA", getattr("ipv6"))
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local function generic_finder(dtype, dec, section, retAll)
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if (#dec[section] > 0) then
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if answerFetcher[dtype] then
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return answerFetcher[dtype](dec[section], retAll)
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else
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stdnse.debug1("dns.lua: no answerFetcher for dtype %s", tostring(dtype))
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return false, "Unable to handle response"
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end
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end
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if not retAll or #answers == 0 then
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stdnse.debug1("dns.answerFetcher found no records of the required type: AAAA")
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elseif (dec.flags.RC3 and dec.flags.RC4) then
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return false, "No Such Name"
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else
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return false, "No Answers"
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end
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return true, answers
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end
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---Calls the answer fetcher for <code>dtype</code> or returns an error code in
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-- case of a "no such name" error.
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--
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@@ -646,126 +583,7 @@ end
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-- @return True if one or more answers of the required type were found - otherwise false.
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-- @return Answer according to the answer fetcher for <code>dtype</code> or an Error message.
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function findNiceAnswer(dtype, dec, retAll)
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if (#dec.answers > 0) then
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if answerFetcher[dtype] then
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return answerFetcher[dtype](dec, retAll)
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else
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stdnse.debug1("dns.findNiceAnswer() does not have an answerFetcher for dtype %s", tostring(dtype))
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return false, "Unable to handle response"
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end
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elseif (dec.flags.RC3 and dec.flags.RC4) then
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return false, "No Such Name"
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else
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stdnse.debug1("dns.findNiceAnswer() found zero answers in a response, but got an unexpected flags.replycode")
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return false, "No Answers"
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end
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end
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-- Table for additional fetching functions.
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-- Some servers return their answers in the additional section. The
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-- findNiceAdditional function with its relevant additionalFetcher functions
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-- addresses this. This unfortunately involved some code duplication (because
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-- of current design of the dns library) from the answerFetchers to the
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-- additionalFetchers.
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local additionalFetcher = {}
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-- Additional fetcher for TXT records.
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-- @param dec Decoded DNS response.
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-- @param retAll If true, return all entries, not just the first.
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-- @return True if one or more answers of the required type were found - otherwise false.
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-- @return String first dns TXT record or Table of TXT records or String Error message.
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additionalFetcher[types.TXT] = function(dec, retAll)
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local answers = {}
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if not retAll and dec.add[1].data then
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return true, string.sub(dec.add[1].data, 2)
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elseif not retAll then
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stdnse.debug1("dns.additionalFetcher found no records of the required type: TXT")
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return false, "No Answers"
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else
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for _, v in ipairs(dec.add) do
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if v.TXT and v.TXT.text then
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for _, v in ipairs( v.TXT.text ) do
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table.insert(answers, v)
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end
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end
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end
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end
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if #answers == 0 then
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stdnse.debug1("dns.answerFetcher found no records of the required type: TXT")
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return false, "No Answers"
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end
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return true, answers
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end
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-- Additional fetcher for A records
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-- @param dec Decoded DNS response.
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-- @param retAll If true, return all entries, not just the first.
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-- @return True if one or more answers of the required type were found - otherwise false.
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-- @return String first dns A record or Table of A records or String Error message.
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additionalFetcher[types.A] = function(dec, retAll)
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local answers = {}
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for _, ans in ipairs(dec.add) do
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if ans.dtype == types.A then
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if not retAll then
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return true, ans.ip
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end
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table.insert(answers, ans.ip)
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end
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end
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if not retAll or #answers == 0 then
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stdnse.debug1("dns.answerFetcher found no records of the required type: A")
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return false, "No Answers"
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end
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return true, answers
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end
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-- Additional fetcher for SRV records.
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-- @param dec Decoded DNS response.
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-- @param retAll If true, return all entries, not just the first.
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-- @return True if one or more answers of the required type were found - otherwise false.
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-- @return String first dns SRV record or Table of SRV records or String Error message.
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-- Note that the format of a returned SRV answer is "priority:weight:port:target" where zero
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-- or more IP addresses may be present.
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additionalFetcher[types.SRV] = function(dec, retAll)
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local srv, ip, answers = {}, {}, {}
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for _, ans in ipairs(dec.add) do
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if ans.dtype == types.SRV then
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if not retAll then
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return true, ("%s:%s:%s:%s"):format( ans.SRV.prio, ans.SRV.weight, ans.SRV.port, ans.SRV.target )
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end
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table.insert( answers, ("%s:%s:%s:%s"):format( ans.SRV.prio, ans.SRV.weight, ans.SRV.port, ans.SRV.target ) )
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end
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end
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if #answers == 0 then
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stdnse.debug1("dns.answerFetcher found no records of the required type: SRV")
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return false, "No Answers"
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end
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return true, answers
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end
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-- Additional fetcher for AAAA records.
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-- @param dec Decoded DNS response.
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-- @param retAll If true, return all entries, not just the first.
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-- @return True if one or more answers of the required type were found - otherwise false.
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-- @return String first dns AAAA record or Table of AAAA records or String Error message.
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additionalFetcher[types.AAAA] = function(dec, retAll)
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local answers = {}
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for _, ans in ipairs(dec.add) do
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if ans.dtype == types.AAAA then
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if not retAll then
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return true, ans.ipv6
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end
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table.insert(answers, ans.ipv6)
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end
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end
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if not retAll or #answers == 0 then
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stdnse.debug1("dns.answerFetcher found no records of the required type: AAAA")
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return false, "No Answers"
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end
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return true, answers
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return generic_finder(dtype, dec, "answers", retAll)
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end
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---
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@@ -777,20 +595,7 @@ end
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-- @return True if one or more answers of the required type were found - otherwise false.
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-- @return Answer according to the answer fetcher for <code>dtype</code> or an Error message.
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function findNiceAdditional(dtype, dec, retAll)
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if (#dec.add > 0) then
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if additionalFetcher[dtype] then
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return additionalFetcher[dtype](dec, retAll)
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else
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stdnse.debug1("dns.findNiceAdditional() does not have an additionalFetcher for dtype %s",
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(type(dtype) == 'string' and dtype) or type(dtype) or "nil")
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return false, "Unable to handle response"
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end
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elseif (dec.flags.RC3 and dec.flags.RC4) then
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return false, "No Such Name"
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else
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stdnse.debug1("dns.findNiceAdditional() found zero answers in a response, but got an unexpected flags.replycode")
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return false, "No Answers"
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end
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return generic_finder(dtype, dec, "add", retAll)
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end
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--
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