SIT Bug

[Gilles Diribarne <gilles.diribarne@xxxxxxxxxxxxx>]

Hi,

I've the following problem on kernel 2.4.3.
I have three interface: eth0, eth1, eth2. I consider that eth0 is IPv6
interface, and eth1, eth2 are IPv4 interface.

Here is the ifconfig
eth0      Link encap:Ethernet  HWaddr 00:01:02:B1:4F:B1
          inet addr:192.168.21.2  Bcast:192.168.21.255
Mask:255.255.255.0
          inet6 addr: fe80::201:2ff:feb1:4fb1/10 Scope:Link
          inet6 addr: 3ffe:400:100:21:201:2ff:feb1:4fb1/64 Scope:Global
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:608 errors:0 dropped:0 overruns:0 frame:0
          TX packets:11585 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:100
          Interrupt:11 Base address:0x1400

eth1      Link encap:Ethernet  HWaddr 00:01:02:AC:CD:72
          inet addr:192.168.52.2  Bcast:192.168.52.255
Mask:255.255.255.0
          inet6 addr: fe80::201:2ff:feac:cd72/10 Scope:Link
          UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
          RX packets:12740 errors:0 dropped:0 overruns:1 frame:0
          TX packets:6856 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:100
          Interrupt:11 Base address:0x1480

eth2      Link encap:Ethernet  HWaddr 00:08:02:DE:00:53
          inet addr:192.168.53.2  Bcast:192.168.53.255
Mask:255.255.255.0
          inet6 addr: fe80::201:2ff:fe0c:45ec/10 Scope:Link
          UP BROADCAST RUNNING PROMISC MULTICAST  MTU:1500  Metric:1
          RX packets:12740 errors:0 dropped:0 overruns:1 frame:0
          TX packets:6856 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:100
          Interrupt:11 Base address:0x1480

lo        Link encap:Local Loopback
          inet addr:127.0.0.1  Mask:255.0.0.0
          inet6 addr: ::1/128 Scope:Host
          UP LOOPBACK RUNNING  MTU:16144  Metric:1
          RX packets:2040 errors:0 dropped:0 overruns:0 frame:0
          TX packets:2040 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0

sit0      Link encap:IPv6-in-IPv4
          inet6 addr: ::127.0.0.1/96 Scope:Unknown
          inet6 addr: ::192.168.21.2/96 Scope:Compat
          inet6 addr: ::192.168.52.2/96 Scope:Compat
          inet6 addr: ::192.168.53.2/96 Scope:Compat
          UP RUNNING NOARP  MTU:1480  Metric:1
          RX packets:21 errors:0 dropped:0 overruns:0 frame:0
          TX packets:1118 errors:13 dropped:0 overruns:0 carrier:13
          collisions:0 txqueuelen:0

The other nodes don't known how to route to subnetwork 192.168.21.0/24
Because I don't set this route. When you set up a IPv4-compatible IPv6
address to allow routing.
# route -Ainet6 ::/96 dev sit0

Now, I want to do a ping, but the ping doesn't work.
Indeed, it takes 192.168.21.2 as Src Address in the ping. I think it
takes the first declared address as default source address.
But, I think it's not logical, because it should take the address
according to the output interface.
I would like to know why Linux choose this one?

Regards,
Gilles

--
 Gilles Diribarne
 Alcatel Research & Innovation
 Gilles.Diribarne@xxxxxxxxxx
 Tel: +33 (0)1 69 63 46 45      Fax: +33 (0)1 69 63 11 69