ferent domains on the same
Xen host only have partial checksums.  Unfortunately this piece of
information is not passed along in AF_PACKET unless you're using
the mmap interface.  Since dhcpd doesn't support packet-mmap, UDP
packets from the same host come out with apparently bogus checksums.

This patch adds a mechanism for AF_PACKET recvmsg(2) to return the
status along with the packet.  It does so by adding a new cmsg that
contains this information along with some other relevant data such
as the original packet length.

I didn't include the time stamp information since there is already
a cmsg for that.

This patch also changes the mmap code to set the CSUMNOTREADY flag
on all packets instead of just outoing packets on cooked sockets.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>