how to figure out which device a given IFB is connected to

Hi All,

I hope I am directing this to the correct mailing list, otherwise please excuse the distraction… 

I am trying to figure out a way to semi-automatically manage a set of IFB devices for a number of network interfaces. Currently I have no problem finding out if a given “real” interfaces is connected to an IFB:

root@nacktmulle:~# tc -s filter show parent ffff: dev ge00
filter protocol all pref 10 u32 
filter protocol all pref 10 u32 fh 800: ht divisor 1 
filter protocol all pref 10 u32 fh 800::800 order 2048 key ht 800 bkt 0 flowid 1:1 
  match 00000000/00000000 at 0
	action order 1: mirred (Egress Redirect to device ifb1) stolen
 	index 47 ref 1 bind 1 installed 521 sec used 3 sec


I am looking for a way of doing the reverse,i.e.  figuring out for a given IFB if it is “connected” to a real interface and, if yes, which interface. Basically, I want to recycle unused IFBs, but want to make sure that they really are unused…

Thanks in advance
	Sebastian Moeller

On Mon, Sep 15, 2014 at 7:37 AM, Sebastian Moeller [off-list ref] wrote:

I am looking for a way of doing the reverse,i.e.  figuring out for a given IFB if it is “connected” to a real interface and, if yes, which interface. Basically, I want to recycle unused IFBs, but want to make sure that they really are unused…

There is no way to figure that out.

Hi Mr. Wang,

Thank you for your help.

On Sep 15, 2014, at 18:08 , Cong Wang [off-list ref] wrote:

On Mon, Sep 15, 2014 at 7:37 AM, Sebastian Moeller [off-list ref] wrote:

quoted

I am looking for a way of doing the reverse,i.e.  figuring out for a given IFB if it is “connected” to a real interface and, if yes, which interface. Basically, I want to recycle unused IFBs, but want to make sure that they really are unused…

There is no way to figure that out.

	That is rather unfortunate, so my only recourse is to get a list of all interfaces and query each whether it is attached to an fib and prune a list of IFBs so that only the unused ones remain (which is far from elegant ;) ).

Best Regards
	Sebastian Moeller

On Mon, 15 Sep 2014 21:06:31 +0200
Sebastian Moeller [off-list ref] wrote:

Hi Mr. Wang,

Thank you for your help.

On Sep 15, 2014, at 18:08 , Cong Wang [off-list ref] wrote:

quoted

On Mon, Sep 15, 2014 at 7:37 AM, Sebastian Moeller [off-list ref] wrote:

quoted

I am looking for a way of doing the reverse,i.e.  figuring out for a given IFB if it is “connected” to a real interface and, if yes, which interface. Basically, I want to recycle unused IFBs, but want to make sure that they really are unused…

There is no way to figure that out.

	That is rather unfortunate, so my only recourse is to get a list of all interfaces and query each whether it is attached to an fib and prune a list of IFBs so that only the unused ones remain (which is far from elegant ;) ).

It can be a many to one mapping.
There are cases where you want multiple incoming devices to all be QoS'd together.

Hello Mr. Hemminger,


On Sep 15, 2014, at 22:55 , Stephen Hemminger [off-list ref] wrote:

On Mon, 15 Sep 2014 21:06:31 +0200
Sebastian Moeller [off-list ref] wrote:

quoted

Hi Mr. Wang,

Thank you for your help.

On Sep 15, 2014, at 18:08 , Cong Wang [off-list ref] wrote:

quoted

On Mon, Sep 15, 2014 at 7:37 AM, Sebastian Moeller [off-list ref] wrote:

quoted

I am looking for a way of doing the reverse,i.e.  figuring out for a given IFB if it is “connected” to a real interface and, if yes, which interface. Basically, I want to recycle unused IFBs, but want to make sure that they really are unused…

There is no way to figure that out.

	That is rather unfortunate, so my only recourse is to get a list of all interfaces and query each whether it is attached to an fib and prune a list of IFBs so that only the unused ones remain (which is far from elegant ;) ).

It can be a many to one mapping.
There are cases where you want multiple incoming devices to all be QoS'd together.

	Good to know, thanks for this information.

Best Regards
	Sebastian Moeller