Common Question?

kerberos kkk kerberos_007 at
Mon Feb 26 18:29:55 PST 2001


if i use http_session_id in http.bro and my_script.bro
i define
global http_session_id = 0 ;
in both the scripts.
It says "already defined".

If i remove from one place it says "Not defined"

Can i get around this prob ? I thought global would make the variable 
visible to all the scripts.


>From: Vern Paxson <vern at>
>To: Phil C <flah at>
>CC: bro at
>Subject: Re: Common Question?
>Date: Sun, 25 Feb 2001 23:48:29 PST
> > I am using bro version 0.7a48, which ofcourse came with the usual slew 
> > scripts in /usr/local/share/bro. Bro always complains about the file 
> > line 197, which is trying to:
> >
> > if ( have_FTP && is_ftp_data_conn(c) )
> >
> > That looks ok to me (have_FTP is set to T), the error is:
> >
> > 982815367.072217 ./conn.bro, line 198 (is_ftp_data_conn): run-time 
>error, value used but not set
>have_FTP should only be true if you did "@load ftp" somewhere in your
>policy script (or loaded one of the standard scripts that does this).
>If you're setting it by hand instead, that's your problem.  If not, please
>send me exactly how you're invoking Bro and with what policy script.
> > One more quick question, what does &redef do? I see it smattered all 
>over but
> > never mentioned in the docs.
>It marks a variable as redefinable (or refinable).  So for example you
>can have:
>	global foo = 5 &redef;
>	...
>	redef foo = 4;
>and the second definition redefines foo's initial value to be 4 rather than 
>You also can use += and -= to redef aggregate variables (tables, sets) to 
>more or fewer members (and you can use += to add to a pattern variable).
>If the first declaration of foo above didn't include &redef, then Bro
>would complain upon seeing the second definition.
>redef is a basic mechanism for allowing one policy script to override
>some of the values in another script so you can express one policy as
>modifications to another policy, rather than having to maintain two
>slightly different versions of the policies.
>		Vern

Get your FREE download of MSN Explorer at

More information about the Bro mailing list