network status

network status

[Sriram V]

Hello,

Apologies in case, this is not the right list of this question.

I wanted to check, How can i find out if a network status has changed

1. How can the user application find out if the link status has changed?
2. what changes do i need to add in the driver to indicate to the user
applications that ethernet cable has been plugged in or unplugged.

3. How should a user application know the status change (Should the
userapp poll on the interface/is there an uevent interface to indicate
the link status change)

Thanks.
Sriram

Re: network status

[Cong Wang]

On Tue, Jan 24, 2017 at 11:39 AM, Sriram V <vshrirama@gmail.com> wrote:
> Hello,
>
> Apologies in case, this is not the right list of this question.
>
> I wanted to check, How can i find out if a network status has changed
>
> 1. How can the user application find out if the link status has changed?

There are some flags per netdevice for its link status, IFF_LOWER_UP
etc., they are sent to user-space via rtnetlink message, ->ifi_flags.


> 2. what changes do i need to add in the driver to indicate to the user
> applications that ethernet cable has been plugged in or unplugged.
>

Probably nothing but calling netif_carrier_on/off() API's.


> 3. How should a user application know the status change (Should the
> userapp poll on the interface/is there an uevent interface to indicate
> the link status change)
>

It needs to subscribe to the rtnetlink group RTNLGRP_LINK to receive
the broadcasts from kernel.