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[PATCH 1/2] net: Fix announce_self
From: |
Laurent Vivier |
Subject: |
[PATCH 1/2] net: Fix announce_self |
Date: |
Fri, 17 Jan 2025 12:17:08 +0100 |
b9ad513e1876 ("net: Remove receive_raw()") adds an iovec entry
in qemu_deliver_packet_iov() to add the virtio-net header
in the data when QEMU_NET_PACKET_FLAG_RAW is set but forgets
to increase the number of iovec entries in the array, so
receive_iov() will only send the first entry (the virtio-net
entry, full of 0) and no data. The packet will be discarded.
The only user of QEMU_NET_PACKET_FLAG_RAW is announce_self.
We can see the problem with tcpdump:
- QEMU parameters:
.. -monitor stdio \
-netdev bridge,id=netdev0,br=virbr0 \
-device virtio-net,mac=9a:2b:2c:2d:2e:2f,netdev=netdev0 \
- HMP command:
(qemu) announce_self
- TCP dump:
$ sudo tcpdump -nxi virbr0
without the fix:
<nothing>
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
Reported-by: Xiaohui Li <xiaohli@redhat.com>
Bug: https://issues.redhat.com/browse/RHEL-73891
Fixes: b9ad513e1876 ("net: Remove receive_raw()")
Cc: akihiko.odaki@daynix.com
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
net/net.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/net/net.c b/net/net.c
index c1bb19a52373..9cded70dde74 100644
--- a/net/net.c
+++ b/net/net.c
@@ -822,6 +822,7 @@ static ssize_t qemu_deliver_packet_iov(NetClientState
*sender,
iov_copy[0].iov_len = nc->vnet_hdr_len;
memcpy(&iov_copy[1], iov, iovcnt * sizeof(*iov));
iov = iov_copy;
+ iovcnt++;
}
if (nc->info->receive_iov) {
--
2.47.1