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I'm having a problem with getting the value of a protofield to the Info column. I've defined the following ProtoField:

f.payload = ProtoField.uint8("observation.payload","payload",base.HEX,{ [0] = "Off", [1] = "On"},0x10)

I want add this field value (On or Off) to pinfo.col.info. How can I do it?

asked 05 Jun '12, 02:00

ekrako's gravatar image

ekrako
6113
accept rate: 0%

edited 05 Jun '12, 16:00

helloworld's gravatar image

helloworld
3.1k42041


You can't extract the value from a ProtoField (see similar question). Instead, you have to parse the buffer, and add the value manually to the Info column, which is fairly easy to do. Try this:

local VALS_ON_OFF = { [0] = "Off", [1] = "On" }

local proto_foo = Proto("foo", "Foo Protocol")
local f = proto_foo.fields
f.payload = ProtoField.uint8("observation.payload", "payload", base.HEX, VALS_ON_OFF, 0x10)

function proto_foo.dissector(buf, pinfo, tree)
   local t = tree:add(proto_foo, buf())

   -- assume observation.payload is at byte 0
   t:add(f.payload, buf(0,1))

   -- 0x10 has one bit set, that's bit 3 from the left
   local bitval = buf(0,1):bitfield(3)

   -- set the Info column based on the bit value
   pinfo.cols.info = "payload: "..VALS_ON_OFF[bitval]
end
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answered 05 Jun '12, 15:54

helloworld's gravatar image

helloworld
3.1k42041
accept rate: 28%

edited 05 Jun '12, 16:01

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question asked: 05 Jun '12, 02:00

question was seen: 2,905 times

last updated: 05 Jun '12, 16:01

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