Hi,
Thanks for reply. Yes, i am talking about ifIndex returned by SIOCGIFINDEX.
Let me describe my system and issue.
On my router system i have two cards (blades)
NP-Blade - one blade has network processor to handle data traffic
at line rate. This
blade is not running linux and has itw own
TCP/UDP/IP stack. The network
interfaces of router are on this blade. The
software on this board assigns
ifIndex to these network interfaces as 1,2,3 ....
10, as there are ten
network interfaces on the board. NP-blade and
CP-blade use IP
for communication.
CP-Blade -second blade is intel processor based, where we are
running routing
protocols ( OSPF, RIP , BGP , ISIS, LDP, RSVP)
and linux is running on it.
These protocols use socket layer of Linux to get
protocol messages
from other routers in the network. We are
creating virtual software interfaces
of "network interfaces" in
NP-blade on CP-Blade. Now, when we are creating
these interfaces
in CP-blade the ifIndex assigned by linux are
not same as what we have
assigned on NP-blade. Also, in linux it depends
in which sequence we
create network interfaces and ifIndex get
assigned. Say, In linux
if we create an interface and delete it and
bring up again, then we will
get different ifIndex.
For software/system point of view we have to keep
NP-blade ifIndex fixed and
NP-blade assumes that ifIndex coming from CP-blade is
1,2,3 ...10. CP-blade
routing protocols creating forwarding table use ifIndex
as assigned by Linux
to calculate ifIndex of next-hop router etc. So, when
CP-blade is sending routing
update to NP-blade we have to do mapping so that next-hop
index, sent to
NP-blade is what CP-blade is expecting.
To avoid this mapping we thought better solution
will be to force NP-blade
ifIndex to linux on CP-blade when creating interfaces and
on CP-blade we don't
need to do any mapping of IfIndex from CP-blade ifIndex
to NP-blade ifIndex.
But in Linux using ioctl we are not able to find any
option to set ifIndex.
Regards,
Anil
On 1/24/07, Stephen Hemminger <shemminger@xxxxxxxxxxxxxxxxxxxx> wrote:
On Tue, 23 Jan 2007 06:55:17 +0530
"Anil Kumar" <anil123@xxxxxxxxx> wrote:
> Hi,
>
> I want to control the interface index assigned to network
> interfaces when they are created in Linux Operating System.
> I am using TUN/TAP driver to create virtual network interfaces in
> linux from user application. Normally by default Linux by itself
> assigns the interface index to the inetrfaces. I can get the inetrface
> information by reading the file /proc/net/igmp or ioctl command.
> My requirement is that i need to assign some fixed interfaces
> index to these interfaces
> created in linux. For example:
> Interface name Interface Index
> =============================
> interface-0
> 10
> interface-1 11
> etc.
>
> Using ioctl i am not finding information how to change the
> interface index. Please let me know how can i assign the fixed
> interface index to network interfaces created in linux OR is there any
> way to control interface index assignment to network interfaces in
> Linux.
>
>
> Regards,
> Anil
I assume you mean the ifindex returned by SIOCGIFINDEX and in
/sys/class/net/XXX/ifindex. There is no API to set it, why do you
need it to be set? It is assigned as a unique value by the kernel
for each new device added.
--
Stephen Hemminger <shemminger@xxxxxxxxxxxxxxxxxxxx>
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