On 2025/01/17 20:17, Laurent Vivier wrote:
When a packet is sent with QEMU_NET_PACKET_FLAG_RAW by QEMU it
never includes virtio-net header even if qemu_get_vnet_hdr_len()
is not 0, and filter-dump is not managing this case.
The only user of QEMU_NET_PACKET_FLAG_RAW is announce_self,
we can show the problem using it and tcpddump:
- QEMU parameters:
.. -monitor stdio \
-netdev bridge,id=netdev0,br=virbr0 \
-device virtio-net,mac=9a:2b:2c:2d:2e:2f,netdev=netdev0 \
-object filter-dump,netdev=netdev0,file=log.pcap,id=pcap0
- HMP command:
(qemu) announce_self
- TCP dump:
$ tcpdump -nxr log.pcap
without the fix:
08:00:06:04:00:03 > 2e:2f:80:35:00:01, ethertype Unknown (0x9a2b), length
50:
0x0000: 2c2d 2e2f 0000 0000 9a2b 2c2d 2e2f 0000
0x0010: 0000 0000 0000 0000 0000 0000 0000 0000
0x0020: 0000 0000
with the fix:
ARP, Reverse Request who-is 9a:2b:2c:2d:2e:2f tell 9a:2b:2c:2d:2e:2f,
length 46
0x0000: 0001 0800 0604 0003 9a2b 2c2d 2e2f 0000
0x0010: 0000 9a2b 2c2d 2e2f 0000 0000 0000 0000
0x0020: 0000 0000 0000 0000 0000 0000 0000
Fixes: 481c52320a26 ("net: Strip virtio-net header when dumping")
Cc: akihiko.od...@daynix.com
Signed-off-by: Laurent Vivier <lviv...@redhat.com>
Reviewed-by: Akihiko Odaki <akihiko.od...@daynix.com>