> On Thursday 06 December 2007 22:31:06 Amos Jeffries wrote:
>> > On Wednesday 05 December 2007 17:04:09 ian j hart wrote:
>> >> Hello.
>> >>
>> >> [sorry, slightly off topic]
>> >>
>> >> I'm the ICT technician of a school. I have squid running to make the
>> >> most
>> >> of our bandwidth. Our ISP provides some content blocking but this is
>> >> proving ineffective against the proliferation of proxy sites.
>> >>
>> >> I've started to monitor and block sites with squid ACLs. This is also
>> >> not
>> >> so effective as there are 1200 users looking for new sites and only 1
>> >> user
>> >> trying to block them.
>> >>
>> >> Since there is no punishment for hitting any DENY ACL there's no
>> reason
>> >> for them to stop.
>> >>
>> >> What I need is to apply some back pressure, i.e. automatically block
>> >> persistant offenders.
>> >>
>> >> Does anyone have anything like this?
>> >>
>> >> N.B. This has to be user based. Host/IP based will not work due to
>> the
>> >> hot seating.
>> >>
>> >> Thanks
>> >
>> > Okay, plan B it is then.
>> >
>> > I'll try and run up a proof of concept implementation so I can see if
>> it
>> > has
>> > the desired affect on the users.
>> >
>> > The minimum info I need is the aclname and user for each deny match.
>> > Other stuff may be useful later (e.g. url).
>> >
>> > Debug statements should be okay. I'll just parse the cache.log.
>> >
>> > What I need help with is where to put the code.
>> >
>> > clientAccessCheckDone looked promising but seems to be called several
>> > times
>> > i.e. proxy auth, blocked url, error page
>> >
>> > Somewhere near the error page generation should be about right.
>> >
>> > Can someone who knows the code lend me their clue stick.
>>
>> If you want to code it. Woudl be better to take it to squid-dev mailinig
>> list. There are more dev helpers there than here.
>
> Okay. I don't meet the criterion to join (ENOTIME) but I could post as a
> guest.
>
>>
>> In general: each of those calls to check ACL are done at the transaction
>> points wherehttp_access, http2_access, https_access, deny_info,
>> http_reply_access if configure to be checked. On a one-*_acess to
>> one-call
>> basis. It's just a matter to figuring which *_access is best to use and
>> finding its ACL test.
>
> You lost me at transaction points...
>
> OTOH something like this...
>
> debug(33,1) ("GREPMESTRING %s %s\n", ACLNAMEMACRO, USERNAMEMACRO);
>
> ...I can cope with.
>
> I'm sure I could do this with the existing debug statements, but parsing a
> single line is much easier than parsing multiple lines.
>
> Like I said, I'm after a proof of concept. Way too many hats to devote the
> time it would need for a good implementation.
>
> Except for the logging the whole thing will be done 'offline'. No need
> then to
> be fast/efficient/well written ;)
>
>>
>> That said. I don't think you should need to code it into squid.
>> The external_acl mechanism can handle real-time blocking based on some
>> external database lookup.
>
> That sounds useful
>
>> From 2.6s17 the logdaemon now allows an
>> external script to get access_log data piped to it for parsing the
>> HIT/MISS/DENIED.
>
>> Based on that all you have to do is an auth ACL 'required' which will
>> add
>> the username to the access log lines.
>
> Already have this. I'm logging all Internet access.
>
> I really want access to the aclname. That way I can have differing penalty
> levels. e.g. games not as serious as porn.
Okay, well in that case, and after a little more thought. I think the best
option for you might be to code up an external helper.
And configure like this:
acl XblockACL dstdomain X
acl XlogACL external ...
http_access deny XblockACL XlogACL
The XlogACL accepts %LOGIN and %ACL, and the 'acl' marks that user against
the name it gets given and replies 'OK' to not override the deny/allow
results from XblockACL.
I'm not certain if the %ACL received by the helper is "XlogACL" or
"XblockACL".
- if its the latter you will only need one logACL
- if its the formar you will need one XlogACL, YlogACL for each level.
HTH
Amos
>
> I don't want to modify the access log format as that might break the
> analysis
> software I'm using.
Amos
