On Thursday, June 19, 2003, at 12:16PM, Shaun Jackman wrote:
Why is COL_INFO set using col_add_fstr, but address columns (like
COL_DEF_SRC) set using SET_ADDRESS(&pinfo->...)?
Because, currently, the columns are set for all packets when the
capture is read in, and that's expensive; setting the address is
cheaper, and, by setting the address in the dissectors and then setting
the column based on the address, it only sets the text once, rather
than once per dissector.
Note also that SET_ADDRESS isn't setting the column, it's setting the
address; setting the address also makes it available to dissectors
called later, and there are many dissectors that make use of that.
I have a higher level protocol (sits above UDP) that has its own
addressing scheme. I wanted to modify the address column to display
more
useful information. After trying col_add_fstr on COL_DEF_SRC and
meeting
with failure, I started looking through the source. It looks like it
can't be done without defining a new AT_* type. This is a simple
in-house plugin that currently builds without modifying the Ethereal
source. I'd like to keep it that way. Can this be done any other way?
Set the address to an AT_NONE address (which means the column won't be
set from the address), and then set the column with one of the
"col_add" routines.
Note, though, that you should do this *after* your dissector uses the
addresses in the pinfo structure (or save the old value and use that),
and that if you do this, any dissectors you call won't have access to
the addresses.
