Wireshark-dev: Re: [Wireshark-dev] Wireshark lua dissector unable to load for media_type=applic
From: Cong Ling <[email protected]>
Date: Sun, 20 Oct 2013 01:59:55 +0800
I think i found the problem after I modified the source code "wslua_proto.c" line 1722 - comment "g_free(pattern);". Because the sub_dissectors->hash_table just add the pattern as point without duplicate a copy in "packet.c".
It should be a bug.


Regards,
✉ Cong Ling

在 2013-10-20,上午12:17,Cong Ling <[email protected]> 写道:

I think it might be the bug of wireshark when the media_type is not list in the dissector table.   'application/octet-stream' is not listed on the table yet.
After I use Lua->evaluate in Wireshark, The dissector table shows my protocol like this, 'application/octet-stream' is in mess code

<屏幕快照 2013-10-20 上午12.05.46.png>

Regards,
✉ Cong Ling

在 2013-10-19,下午10:50,Cong Ling <[email protected]> 写道:


Hi all,
I'm trying to write a lua Proto to parse our private protocol on http. But Wireshark didn't enter my dissector function when the media_type to "application/octet-stream". When the media_type is set to "text/html", everything looks fine.
Is there special handling for application/octet-stream?
I was working on it for almost a day, Could you help me out?
Thx a lot

My wireshark version is 1.10.2 on mac osx 10.8.5

Here's my code

do
   local myproto= Proto("myprotoProtocol","myproto Protocol")
   local f_version= ProtoField.uint32("Version","Version",base.DEC)
   myproto.fields = {f_version}
   local data_dis = Dissector.get("data")
   local function myproto_dissector(tvb,pkt,root)
           print("enter myproto_dissector, tvb.len:"..tostring(tvb:len()))
           if tvb:len() < 17 then return false end
           pkt.cols.protocol = "myproto"
           local t =root:add(myproto,tvb)
           t:add(f_version,tvb(0,2))
           local version = tvb(0,2).uint()
           print("version:"..tostring(version))
           return true
   end

   function myproto.dissector(tvb,pkt,root)
           print("enter myproto.dissector")
           if not myproto_dissector(tvb,pkt,root) then
                   data_dis:call(tvb,pkt,root)
           end
   end

   local tbl= DissectorTable.get("media_type")
   tbl:add("application/octet-stream",myproto)
   --tbl:add("text/html",myproto) --text/html looks fine
   print("adding myproto into DissectorTable")
end

I use tshark to debugging for application/octet-stream

$tshark  -r test.pcapng   |grep application/octet-stream
108 40.536817000    10.8.0.14 -> 10.130.142.72 HTTP 418 POST /protocol?uid=101225&uid=101225&_t=1382115502 HTTP/1.1  (application/octet-stream)
111 40.596037000 10.130.142.72 -> 10.8.0.14    HTTP 63 HTTP/1.1 200 OK  (application/octet-stream)
120 40.657143000    10.8.0.14 -> 10.130.142.72 HTTP 445 POST /protocol?uid=101225&uid=101225&_t=1382115502    HTTP/1.1  (application/octet-stream)
124 40.729645000 10.130.142.72 -> 10.8.0.14    HTTP 63 HTTP/1.1 200 OK  (application/octet-stream)
219 41.810493000    10.8.0.14 -> 10.130.142.72 HTTP 488 POST /protocol?uid=101225&uid=101225&_t=1382115503 HTTP/1.1  (application/octet-stream)
226 41.919401000 10.130.142.72 -> 10.8.0.14    HTTP 63 HTTP/1.1 200 OK  (application/octet-stream)

$tshark  -r test.pcapng   -X lua_script:canon.lua | grep myproto
adding myproto into DissectorTable

for text/html

$tshark  -r test.pcapng   -X lua_script:canon.lua | grep myproto
adding myproto into DissectorTable
enter myproto.dissector
enter myproto_dissector, tvb.len:2
enter myproto.dissector
enter myproto_dissector, tvb.len:6
enter myproto.dissector
enter myproto_dissector, tvb.len:6



Regards,
Cong Ling

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