[dnsdist] LUA DNS Parser

[Otto Moerbeek]

On Fri, Jun 20, 2025 at 12:43:04AM -0700, japantoday--- via dnsdist wrote:

> I was attempting to run this sample code I found on the website.
> 
> function dumpPacket(dq)
>   local packet = dq:getContent()
>   local overlay = newDNSPacketOverlay(packet)
>   print(overlay.qname)
>   print(overlay.qtype)
>   print(overlay.qclass)
>   local count = overlay:getRecordsCountInSection(DNSSection.Answer)
>   print(count)
>   for idx=0, count-1 do
>     local record = overlay:getRecord(idx)
>     print(record.name)
>     print(record.type)
>     print(record.class)
>     print(record.ttl)
>     print(record.place)
>     print(record.contentLength)
>     print(record.contentOffset)
>   end
>   return DNSAction.None
> end
> 
> addAction(AllRule(), LuaAction(dumpPacket))
> 
> 
> 
> 
> Essentially, it should print out details about the DNS answer it received.
> 
> On my machine, I get nothing.  It thinks count is always 0, when in fact
> that is not true.  At this point I am trying to figure out why this code
> does not work.

Queries have no response data. Try

addResponseAction(AllRule(), LuaResponseAction(dumpPacket))

	-Otto