Ian Batterbee said:
> Ah okay, I had assumed it was a more generic system where any of the known
> packet fields could be a column - that would be a nice feature if someone
> is kind enough to write it,
It would also be an expensive feature, as it would require that, to
generate the summary line for a packet, the protocol tree would have to be
constructed; that would significantly slow down reading in capture files
(compare, for example, reading in a file with a color filter and reading
in a file without a color filter - the latter is probably noticeably
faster, at least for files large enough for the difference not to be lost
in the constant term).
An option to allow a user to specify that a column with a given title be
displayed with a given field value, so that if one wasn't specified (and
no filtering or coloring was done) no protocol tree would be constructed,
would work (there's already a mechanism, in the code to construct the
protocol tree, to handle specially fields marked as "interesting", so
there should be no extra cost to constructing the protocol tree if no
field was being displayed).
With a mechanism to allow specification of the columns in the Tethereal
command line, that might be an alternative to -zproto,colinfo as well.
Frequently-specified values should probably be given their own column
type, so that you don't have to pay the penalty of constructing a protocol
tree to display the field in question.