Hi Ben,
Thanks for the mail.
Is there any means by which I can identify if the notification is for IP
address (or) netmask address for RTM_NEWADDR?
Thanks and regards,
Sathya
On Sat, Oct 3, 2009 at 3:59 AM, Ben Hutchings <b...@decadent.org.uk> wrote:
> On Fri, 2009-10-02 at 23:40 +0530, sathya sai wrote:
> [...]
> > But, when I reconfigure my network interface with the below ifconfig
> > command, I am shocked that the above netlink program is giving me two
> > notifications with RTM_NEWADDR (new address being added to an
> > interface)
> >
> > I am not sure why the second ifconfig command gives me the two
> > RTM_NEWADDR netlink notifications?
> >
> > ifconfig eth0 inet 0
> > ifconfig eth0 inet 10.208.34.114 netmask 255.255.255.0
> >
> > To analyse further on this, I then changed the second ifconfig to as
> > in below(removed the netmask part),
> >
> > ifconfig eth0 inet 10.208.34.114
> >
> > Now I am getting only one RTM_NEWADDR netlink notification from the
> > kernel.(although the netmask and broadcast address as been assigned to
> > the default address by the kernel).
> >
> > Could you please help me out by answering why with my prior netlink
> > command the debian kernel was triggering two RTM_NEWADDR
> > notifications.
>
> If I run:
> strace ifconfig eth0 inet 10.208.34.114 netmask 255.255.255.0
> it shows me:
> ioctl(4, SIOCSIFADDR, 0xff97ca88) = 0
> ioctl(4, SIOCGIFFLAGS, {ifr_name="eth0",
> ifr_flags=IFF_UP|IFF_BROADCAST|IFF_MULTICAST}) = 0
> ioctl(4, SIOCSIFFLAGS, 0xff97c98c) = 0
> ioctl(4, SIOCSIFNETMASK, 0xff97ca88) = 0
>
> So the address and netmask configuration are two separation operations
> that are notified separately.
>
> Ben.
>
> --
> Ben Hutchings
> Who are all these weirdos? - David Bowie, about L-Space IRC channel #afp
>
