[libvirt] [PATCH v2] nwfilter: Discard class D and E IP addresses when sniffing packets

[Stefan Berger]

Stefan Berger
IBM T. J. Watson Research Center, 
Hawthorne, NY, USA
tel#: +1 914 784 7767 , 
fax#: +1 914 784 6225
e-mail: stefanb at us.ibm.com

libvir-list-bounces at redhat.com wrote on 08/13/2010 04:21:45 PM:

> [image removed] 
> 
> Re: [libvirt] [PATCH v2] nwfilter: Discard class D and E IP 
> addresses when sniffing packets
> 
> Eric Blake 
> 
> to:
> 
> Stefan Berger
> 
> 08/13/2010 04:36 PM
> 
> Sent by:
> 
> libvir-list-bounces at redhat.com
> 
> Cc:
> 
> libvir-list
> 
> On 08/13/2010 02:15 PM, Stefan Berger wrote:
> >  V2: Corrected comment and simplified mask to check for class D and E 
IP
> > addresses
> > 
> > When sniffing the network traffic, discard class D and E IP addresses
> > when sniffing traffic. This was a reason why filters were not 
correctly
> > rebuilt on VMs on the local 192.* network when libvirt was restarted 
and
> > those VMs did not use a DHCP request to get its IP address.
> > 
> 
> > -                    // skip eth. bcast and mcast addresses,
> > -                    // and zero address in DHCP Requests
> > -                    if ((ntohl(vmaddr)&  0xc0000000) || vmaddr == 0) 
{
> > +                    // skip mcast addresses (224.0.0.0 - 
239.255.255.255),
> > +                    // class E (240.0.0.0 - 255.255.255.255, includes 
eth.
> > +                    // bcast) and zero address in DHCP Requests
> > +                    if ( (ntohl(vmaddr)&  0xe0000000) == 0xe0000000 
||
>                                           ^^
> [stupid thunderbird bug - why does it reformat quoted text for no 
reason?]

Wow, yes, that's not how I posted it.

Could have also done something like (ntohl(vmaddr) >> 29) == 7, but what 
we have is easier to understand...

> 
> > +                         vmaddr == 0) {
> 
> ACK; looks better.

Pushed.

  Stefan
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