Re: openbsd routing logic confused by ip prefixes - correction

["=?iso-8859-15?Q?Jos=E9?= M. =?iso-8859-15?Q?Fandi=F1o?=" <openbsd@fadesa.es>]

Dan Harnett wrote:
> 
> On Wed, Feb 04, 2004 at 03:55:58PM +0100, José M. Fandiño wrote:
> > Hello,
> >
> > > I have an ethernet segment with different network prefixes,
> > > concretely: 195.55.55.0/25 and 195.55.55.128/26.
> > > (195.55.55.192/26 was not assigned to me)
> >
> > sorry £ukasz , I write wrong prefixes, they are:
> > 195.55.55.0/26 <- gateway block
> > 195.55.55.64/26 <- BSD box
> > 195.55.55.128/26 <- for future use
> > *195.55.55.192/26 is not mine.
> > http://www.ripe.net/perl/whois?form_type=simple&full_query_string=&searchtext=195.55.55.0&do_search=Search
> 
> Ahhh...  That makes more sense.
> 
> > fuego2# route add -host 195.55.55.1 195.55.55.66 -interface
> > Feb 3 22:27:22 fuego2 /bsd: arp_rtrequest: bad gateway value
> > add host 195.55.55.1: gateway 195.55.55.66
> > fuego2#
> > fuego2# netstat -rn -f inet
> 
>   # route add -net 195.55.55.0/26 -interface 195.55.55.66

yes, I did that test before sending a mail to misc@ but
the current scenario is more complex. 

I will need to do proxy-arp for legacy boxes in the 
first block, I think that a little ascii diagram can 
explain it better:

                 195.55.55.1                   old network 195.55.55.0/26
|INTERNET|---|GW|----------------------|OBSD |-------------
                           195.55.55.66 (with proxyarp for the old network)

As you can see I need a more specific route for 195.55.55.1/32 
in the external interface and a network route to 195.55.55.0/26 
in the internal. This is very easy to setup in GNU/Linux, all the
problem is add a 195.55.55.1/32 route to OpenBSD.

** Even adding a route like this works:
route add -net 195.55.55.0/30 -interface 195.55.55.66

but a host route (read 195.55.55.1/32) fails, and it
fails only with OpenBSD. :-?

If I run "tcpdump -i xl0 -n host 195.55.55.1 or host 195.55.55.66"
to see the wire, the OpenBSD tcp/ip stack _don't_send_packets_.

I think it's a problem which the routing logic of OBSD,
why a can setup a /30 route and not a /32 route to 
195.55.55.1?

	/-----/

fuego2# ping 195.55.55.1
PING 195.55.55.1 (195.55.55.1): 56 data bytes
Feb 3 22:28:38 fuego2 /bsd: arpresolve: can't allocate llinfo
^C--- 195.55.55.1 ping statistics ---
5 packets transmitted, 0 packets received, 100.0% packet loss

fuego2# netstat -rn -f inet
Routing tables

Internet:
Destination        Gateway            Flags     Refs     Use    Mtu  Interface
127/8              127.0.0.1          UGRS        0        0  33224   lo0
127.0.0.1          127.0.0.1          UH          1        0  33224   lo0
195.55.55.1        195.55.55.66       UHS         0        0      -   xl0
195.55.55.64/26    link#1             UC          0        0      -   xl0
224/4              127.0.0.1          URS         0        0  33224   lo0

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