libvir-list-boun...@redhat.com wrote on 08/13/2010 03:11:25 PM:
>
> On 08/13/2010 12:38 PM, Stefan Berger wrote:
> > 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.
> >
> > Signed-off-by: Stefan Berger <stef...@us.ibm.com>
> >
> > ---
> > src/nwfilter/nwfilter_learnipaddr.c | 7 +++++--
> > 1 file changed, 5 insertions(+), 2 deletions(-)
> >
> > Index: libvirt-acl/src/nwfilter/nwfilter_learnipaddr.c
> > ===================================================================
> > --- libvirt-acl.orig/src/nwfilter/nwfilter_learnipaddr.c
> > +++ libvirt-acl/src/nwfilter/nwfilter_learnipaddr.c
> > @@ -546,9 +546,12 @@ learnIPAddressThread(void *arg)
> > struct iphdr *iphdr = (struct iphdr*)(packet +
> > ethHdrSize);
> > vmaddr = iphdr->saddr;
> > - // skip eth. bcast and mcast addresses,
> > + // skip eth. bcast and mcast addresses (224.0.0.0
-
> > + // 239.255.255.255), class E (255.*)
> > // and zero address in DHCP Requests
> > - if ((ntohl(vmaddr) & 0xc0000000) || vmaddr == 0)
{
> > + if ( (ntohl(vmaddr) & 0xe0000000) == 0xe0000000
||
>
> This line's fine for 224-239.*, but...
>
> > + (ntohl(vmaddr) & 0xf0000000) == 0xf0000000
||
>
> shouldn't this be (ntohl(vmaddr) & 0xff000000) == 0xff000000, so that
> you are not excluding 254.*?
>
Looking at Wikipedia for this
http://en.wikipedia.org/wiki/Classful_network
Class D addresses have highest bits with pattern 1110 0000 -> 0xe0
Class E addresses have highest bits with pattern 1111 0000 -> 0xf0
I think my masks are fine and the masking with 0xf0 00 00 00 should also
include 254.* = 0xfe.* .
Stefan
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