Fix CVE-2021-3416
Some NIC supports loopback mode and this is done by calling
nc->info->receive() directly which in fact suppresses the effort of
reentrancy check that is done in qemu_net_queue_send().
Unfortunately we can use qemu_net_queue_send() here since for loop
back there's no sender as peer, so this patch introduce a
qemu_receive_packet() which is used for implementing loopback mode
for a NIC with this check.
NIC that supports loopback mode will be converted to this helper.
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: Jiajie Li <lijiajie11@huawei.com>
