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Re: [Qemu-devel] Re: [PATCH] networking using libpcap
From: |
Anthony Liguori |
Subject: |
Re: [Qemu-devel] Re: [PATCH] networking using libpcap |
Date: |
Fri, 25 Jul 2008 15:51:12 -0500 |
User-agent: |
Thunderbird 2.0.0.14 (X11/20080501) |
Jung-uk Kim wrote:
On Friday 18 July 2008 12:12 pm, Sebastian Herbszt wrote:
I simplified FreeBSD ports patch with the above patch:
http://people.freebsd.org/~jkim/qemu-devel-20080620_1-pcap.diff
I spent some time with this patch looking to merge it. It seems to have
decent performance and is very easy to use. Unfortunately, I ran into
the following:
1) If I specify -net pcap,ifname=eth0 -net nic,model=rtl8139, I get an
error, whereas if I specify -net nic,model=rtl8139 -net pcap,ifname=eth0
it works. The reason for this is that in net_pcap_init(), you search
the vlan to discover what the IP address is of the NIC on the vlan is.
This is a big no-no as you can have one or more NICs on a single vlan.
Moreover, NICs can be added and removed from a vlan long after it's
created. The patch needs a fair bit more work to handle this proper
(presumably building a new filter rule as NICs are added and removed
from the vlan).
2) When using ifname=eth0, traffic doesn't work from host=>guest nor
from guest=>host. This seems like a major short-coming to me. Having
another networking option that is easy to use but doesn't work in some
fundamental way that a user would expect seems like it's just going to
lead to even further confusion. This patch isn't attractive to me
unless it works just like you were bridging to a physical interface (and
I don't think there's anything fundamental preventing that).
If you can fix these issues, I'd be happy to merge this feature.
Regards,
Anthony Liguori
Thanks!
Jung-uk Kim
Re: [Qemu-devel] Re: [PATCH] networking using libpcap, Anthony Liguori, 2008/07/22