On 07/15/2010 03:22 PM, Miguel Di Ciurcio Filho wrote:
Hello,
This is a prototype suggestion. I mostly copied and pasted the code from
net/dump.c into net.c and made some adjustments. There is no command line
parsing involved yet, just the internals and small changes in net/tap.c and
net/slirp.c do make the thing work.
In my tests, using tap as backend, e1000 as a guest device and running iperf
from
guest to host, the overhead of dumping the traffic caused a loss of around 30%
of performance.
I opened the dumped files in wireshark and they looked fine. When using slirp
all requests were dumped fine too.
A less invasive way to do this would be to chain netdev devices.
Basically:
-netdev tap,fd=X,id=foo
-netdev dump,file=foo.pcap,netdev=foo,id=bar
-net nic,model=virtio,netdev=bar
I think this has some clear advantages to this architecturally. From a
user perspective, the only loss is that you have to add the dump device
at startup (you can still enable/disable capture dynamically).
Regards,
Anthony Liguori
Bugs/limitations:
- I have no clue on how to deal with tap+vhost, is it necessary?
- When using virtio-net, I'm not sure how to handle iovec when vnet_hdr=on
- Create a function to add dump to a netdev on the fly, is it necessary?
- Handle cleanups
Miguel Di Ciurcio Filho (4):
net/dump: Make pcap structures public
net: Introduce NetClientDump and auxiliary functions
net/tap: Suggested support for NetClientDump
net/slirp: Suggested support for NetClientDump
net.c | 90 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
net.h | 8 +++++
net/dump.c | 21 -------------
net/dump.h | 21 +++++++++++++
net/slirp.c | 3 ++
net/tap.c | 3 ++
qemu-common.h | 1 +
7 files changed, 126 insertions(+), 21 deletions(-)
