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

Eric Blake eblake at redhat.com
Fri Aug 13 20:21:45 UTC 2010


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?]

> +                         vmaddr == 0) {

ACK; looks better.

-- 
Eric Blake   eblake at redhat.com    +1-801-349-2682
Libvirt virtualization library http://libvirt.org

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