Ability to live lock 5.3 via routing...

[Vladimir Grebenschikov]

В ср, 10/11/2004 в 06:38 -0800, Sean Chittenden пишет:
> >> Pretty easy for me to reproduce.  The machine live locks so I can't 
> >> get
> >> anything out of it, serial console or otherwise.  :(  Imagine a 
> >> machine
> >> with two NICs, fxp0 and fxp1 (though it could be any two NICs).  The
> >> following commands should lead to a lock:
> >>
> >> # Add the primary address on the external NIC
> >> ifconfig fxp0 192.168.1.2 netmask 255.255.255.0 media 100baseTX
> >> mediaopt full-duplex
> >>
> >> # Add the default gateway
> >> route add default 192.168.1.1
> >>
> >> # Add a network to the internal interface
> >> ifconfig fxp1 10.10.10.1 netmask 255.255.255.0 media 100baseTX 
> >> mediaopt
> >> full-duplex
> >>
> >> # On the external interface, on the same VLAN, there are two other
> >> networks.
> >> # Add aliases that way the machine can participate on those networks.
> >> ifconfig fxp0 alias 192.168.2.250 netmask 255.255.255.255
> >> ifconfig fxp0 alias 192.168.3.250 netmask 255.255.255.255
> >
> > You should use the correct netmask for the networks:
> > e.g.:
> > ifconfig fxp0 alias 192.168.2.250 netmask 255.255.255.0
> > or:
> > ifconfig fxp0 alias 192.168.2.250/24
> > /32 is only correct if you are adding an alias for a network you
> > already participate.
> 
> *grabs pointy hat*  You're right, I knew better.  When using the 
> correct netmasks to the interface aliases, everything works without a 
> hitch.  Forgot to change the netmasks when "evolving" this particular 
> mess of subnets and fired off an inquiry.  Still, setting /32's and 
> designating routes that hang off of a host address works (and 
> rightfully it should) until that third route is added, then everything 
> goes apeshit.  Regardless, thanks for the obvious fix... still not sure 
> why it does this though.  If someone doesn't pick it up in the next 
> week, I'll file a PR so it doesn't get lost.  -sc

Actually your actions should not lead to lockup anyway.
It is possible to add interface route even if you have no address on
this subnet, please try:

route add -net 192.168.2.0/24 -iface fxp0 -cloning
route add -net 192.168.3.0/24 -iface fxp0 -cloning

but anyway, you should not point by routes to yourself

-- 
Vladimir B. Grebenchikov
vova at fbsd.ru