[Bro-Dev] #861: Merging DNP3 Analyzer

[Bro Tracker]

#861: Merging DNP3 Analyzer
---------------------+------------------------
  Reporter:  hui     |      Owner:  robin
      Type:  Task    |     Status:  assigned
  Priority:  Normal  |  Milestone:  Bro2.2
 Component:  Bro     |    Version:  git/master
Resolution:          |   Keywords:  dnp3
---------------------+------------------------

Comment (by hui):

 HI, Robin,

 Can you please take a look at current version of the codes. I added
 documentation on the analyzer.

 The work that left undone so far is
 (1) so far, we support logic DNP3 application layer fragment as long as
 65536.
 (2) documentation on protocol validation policy, the policy that checks
 some rules defined by DNP3 protocols

 Best,

 Hui Lin

 On Sat, Oct 6, 2012 at 8:30 PM, Bro Tracker <bro at tracker.bro-ids.org>
 wrote:

 > #861: Merging DNP3 Analyzer
 > ---------------------+------------------------
 >   Reporter:  hui     |      Owner:  robin
 >       Type:  Task    |     Status:  assigned
 >   Priority:  Normal  |  Milestone:  Bro2.2
 >  Component:  Bro     |    Version:  git/master
 > Resolution:          |   Keywords:  dnp3
 > ---------------------+------------------------
 >
 > Comment (by hui):
 >
 >  Replying to [comment:12 seth]:
 >  > > I think what you said is the "incremental parsing"
 >  > > mentioned in the binpac paper. But actually, I am not quite sure
 how
 >  this
 >  > > is implemented in the binpac. Can you please direct me to some
 codes
 >  that
 >  > > I refer to?
 >  >
 >  > It's actually not something you even need to worry about.  Just
 >  instantiate your binpac parser and begin passing data into it as you
 >  receive it, the binpac parser will take care of the data even if it
 >  doesn't receive the full PDU in one go.
 >
 >  Just come up another question. When a HTTP fragment is very long and
 >  carried in different network packets, the HTTP binpac analyzer should
 know
 >  the length of the whole fragment when the first application layer trunk
 is
 >  received. Is this correct? The HTTP message contains some field to
 >  indicate that length, right?
 >
 >  But for DNP3 analyzer, this is not possible. I know the length of the
 >  whole logical DNP3 fragment only when the last trunk is received. To
 >  better explained
 >
 >  TCP : DNP3 Pseudo Data Link Layer (length field is 255) : DNP3 Pseudo
 Data
 >  Transport Layer : DNP3 Pseudo Application Layer #1
 >  TCP : DNP3 Pseudo Data Link Layer (length field is 255) : DNP3 Pseudo
 Data
 >  Transport Layer : DNP3 Pseudo Application Layer #2
 >  ....
 >  TCP : DNP3 Pseudo Data Link Layer (length field is x) : DNP3 Pseudo
 Data
 >  Transport Layer : DNP3 Pseudo Application Layer #n
 >
 >  So the length field in the Pseudo Data Link does not contain the length
 of
 >  the whole DNP3 fragment, but the length of the trunk following this
 data
 >  link layer. So in order to know the whole length of the DNP3 fragment
 (in
 >  this case is , 255 + 255 + ... + x), all the application layer trunk
 has
 >  to be received. So is there any way to use incremental parsing in the
 >  binpac in this case?
 >
 > --
 > Ticket URL: <http://tracker.bro-ids.org/bro/ticket/861#comment:13>
 > Bro Tracker <http://tracker.bro-ids.org/bro>
 > Bro Issue Tracker
 >

-- 
Ticket URL: <http://tracker.bro-ids.org/bro/ticket/861#comment:14>
Bro Tracker <http://tracker.bro-ids.org/bro>
Bro Issue Tracker