[Olsr-dev] problem with olsr-0.5.6 branch: old links remain in the topology

[Henning Rogge]

Am Monday 02 February 2009 11:27:34 schrieb Henning Rogge:
> Am Sunday 01 February 2009 23:05:33 schrieb L. Aaron Kaplan:
> > Hi!
> >
> > So, Henning and me were debugging tonight... we could reproduce a bug
> > which was reported by markus kittenberger earlier.
> > Problem is that when one node loses connectivity (in the experiment
> > olsrd was killed there), then other nodes will keep a route to it.
> > This is IMHO still a showstopper for 0.5.6-r4.
> >
> > Testsetup (how to repeat):
> >
> > 192.168.100.1  (linksys, freifunk firmware 1.3.36)
> >
> >     |         \
> >     |          \
> >     |    -----> \ 192.168.100.127 (freebsd, olsr-0.5.6 branch )
> >     |<--/
> >
> >   192.168.100.126 (openbsd, olsr-0.5.6 branch)
> >
> >
> > so all nodes see each other.
> >
> > The topology tables of 100.127 will still show:
> >
> > Source IP addr  Dest IP addr          LQ        ETX
> > 192.168.100.1   192.168.100.126 0.592/1.000    1.689
> > 192.168.100.1   192.168.100.127 0.541/0.992    1.862
> > 192.168.100.126 192.168.100.1   0.996/0.514    1.954
> > 192.168.100.126 192.168.100.127 0.984/0.965    1.053
> > 192.168.100.127 192.168.100.1   0.996/0.529    1.896
> > 192.168.100.127 192.168.100.126 0.984/0.992    1.024
> >
> >
> > Let ETX values settle to ~ 1.0. Then turn off for example 100.126.
> > Afterwards the topology table will look like this:
> >
> > Source IP addr  Dest IP addr          LQ        ETX
> > 192.168.100.1   192.168.100.126 0.592/1.000    1.689
> > 192.168.100.1   192.168.100.127 0.541/0.992    1.862
> > 192.168.100.127 192.168.100.1   0.996/0.529    1.896
> > 192.168.100.127 192.168.100.126 0.984/0.992    1.024
> >
> > So essentially the entries with src address 100.126 were deleted.
> > But the nodes 100.127 and 100.1 still keep a topology link to 100.126
> > even though it is gone!
> >
> >
> > Henning and me stepped thru the src/link_set.c functions
> > static void olsr_delete_link_entry(struct link_entry *link)
> >    and
> >
> > void olsr_set_link_timer(struct link_entry *link, unsigned int
> > rel_timer)
> >
> > olsr_set_link_timer gets actually called regularly.
> > olsr_delete_link_entry seems to get called once.
> >
> > Nevertheless the wrong topology entries still remain.
> >
> > More debugging is needed here. I am just documenting this here now,
> > maybe someone else can spot the bug.
>
> I just pushed a fix for this problem into the stable tree. I was a
> combination of two small (but important) bugs.
>
> Should work now.
Just pushed a patch for the same problem in the development tree too.

Henning

*************************************************
Diplom Informatiker Henning Rogge
Forschungsgesellschaft für
Angewandte Naturwissenschaften e. V. (FGAN) 
Neuenahrer Str. 20, 53343 Wachtberg, Germany
Tel.: 0049 (0)228 9435-961
Fax: 0049 (0)228 9435-685
E-Mail: (spam-protected)
Web: www.fgan.de
************************************************
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Vorstand: Prof. Dr. rer. nat. Maurus Tacke (komm. Vors.), Prof. Dr.-Ing. 
Joachim Ender (Stellv.)

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