[PATCH] QEMU networking with libpcap

[Jung-uk Kim]

I was trying to fix slirp but I have given up because the slirp is 
very 64-bit unfriendly.  In fact, it was taken from FreeBSD's 
src/sys/netinet but it was well before the following commit:

http://docs.freebsd.org/cgi/mid.cgi?199808240747.AAA16217

Unfortunately there were too many changes between slirp code fork and 
this fix.  On top of that, the author bastardized mbuf chain, so that 
we cannot merge this directly.

Instead I found this:

http://qemu-forum.ipi.fi/viewtopic.php?p=5646&sid=494a2df12b48a1e8fdca8ae0e7bfb752

and re-wrote most of the code:

http://people.freebsd.org/~jkim/patch-qemu-pcap.diff

The option to use is '-net nic -net pcap' and it should be able to 
pick up right network interface for you.  If not, use '-net nic -net 
pcap,ifname=<YOUR_NIC_HERE>' instead.  But of course, you need access 
to /dev/bpf*.  Modify /etc/devfs.conf or /etc/devfs.rules to set 
permissions right for you.  Downside is host and guest cannot talk 
directly because it uses bpf(4).  And it seems slow for an unknown 
reason on my FreeBSD/amd64 -CURRENT host. :-(  Let me know if anyone 
knows why.

Enjoy,

Jung-uk Kim