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

[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.

Henning

*************************************************
Diplom Informatiker Henning Rogge
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