Hi Thomas, Jason, Stefan
I'm reading the QEMU network subsystem and am thinking implement a
network filter between network backend and NIC devices. All packets
will pass by this filter, therefore, dump can be easily done with
the filter.
+--------------+ +-------------+
+----------+ | filter | |frontend(NIC)|
| real | | | | |
| network <--+backend <-------+ |
| backend | | peer +-------> peer |
+----------+ +--------------+ +-------------+
The filter is actually a full featured network backend, either you
can call this a transparent proxy.
A prototype patch will be sent in reply to this mail. The patch tested
with tap backend.
I want your input about whether this is plausible or the design of this
is completely wrong?
Thank you in advance.
On 07/13/2015 03:39 PM, Thomas Huth wrote:
The "-net dump" option only works with the "-net" option. So far, it
is not possible to dump network traffic with the "-netdev" option yet.
This patch series now fixes this ugliness by enabling dumping for the
"-netdev" option, too.
Unlike with the "-net dump" option, the "-netdev" parameter does not
"abuse" the disliked internal vlan hub infrastructure to achieve this
functionality. This patch series introduces a new, clean "dumpfile=xxx"
option for the -netdev parameters instead.
The patches are intended for QEMU version 2.5, but I'm sending them
now already in case somebody got some spare minutes left for reviewing
them again.
Note: I did not address multiqueue devices yet (but added a TODO in the
source code) ... I will address that later when the basic patches have
been accepted.
v2:
- Restructured the code a little bit
- Updated target QEMU version from 2.4. to 2.5
- Addressed review feedback from Jason, Stefan and Markus:
- Use iov_copy() instead of copying the iov manually
- Fix return value of net_dump_receive_iov() if fd is invalid
- Use get_vhost_net() to detect vhost devices
- Close the fd when netdev is deleted
- Added some more comments in the source code
Thomas Huth (5):
net/dump: Add support for receive_iov function
net/dump: Move DumpState into NetClientState
net/dump: Rework net-dump init functions
net/dump: Add dump option for netdev devices
qemu options: Add information about dumpfile to help text
include/net/net.h | 8 +++++
net/clients.h | 6 ++++
net/dump.c | 99 +++++++++++++++++++++++++++++++++++++++----------------
net/net.c | 38 ++++++++++++++++++++-
qapi-schema.json | 12 +++++--
qemu-options.hx | 26 ++++++++++-----
6 files changed, 149 insertions(+), 40 deletions(-)
--
Thanks,
Yang.
