[Olsr-dev] v0.5.6 rc3 / no interface detection if device-label is used

Bastian Bittorf (spam-protected)
Wed Dec 3 13:49:35 CET 2008

On the big weimar.freifunk.net meshwork we use
a server which interconnects the clouds by vpn
and speaks olsr on each tunnel/tap-interface.


Since a long time this service didn't work and
today I tracked down an olsrd-bug i think:

All interfaces are assigned by:

ip address add dev tap31 label tap31:thomas

This is for better understanding the output
of 'ip address show' (the labels are humanreadable)

By starting olsr with debug 1 it turns out, that all
labeled interfaces are overriden - the message is:

"Checking tap31: No such interface!"

By simply adding a non-labeled /32 ip
to the same interface, it works:

ip address add dev tap31

I think this behaviour (don't want to say it's a "bug") is
in the code since a long time, maybe ever? Also interesting,
that tcpdump has something similar:

(spam-protected):~# ip address show dev tap0
177: tap0: <BROADCAST,MULTICAST,UP> mtu 1450 qdisc pfifo_fast qlen 1000
    link/ether 00:ff:cf:1f:51:6e brd ff:ff:ff:ff:ff:ff
    inet scope global tap0:meyer23flur

(spam-protected):~# tcpdump -ni tap0 port 698
tcpdump: WARNING: tap0: no IPv4 address assigned
listening on tap0, link-type EN10MB (Ethernet), capture size 68 bytes

(spam-protected):~# ip address add dev tap0

(spam-protected):~# tcpdump -ni tap0 port 698
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on tap0, link-type EN10MB (Ethernet), capture size 68 bytes

Recognize the "WARNING: tap0: no IPv4 address assigned" during
first tcpdump-startup - maybe that helps...

Greetings from the Weimar-Mesh - Bastian Bittorf

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