diff options
| author | Ed Swierk <eswierk@skyportsystems.com> | 2017-11-16 06:06:06 -0800 |
|---|---|---|
| committer | Jason Wang <jasowang@redhat.com> | 2017-11-20 11:08:00 +0800 |
| commit | 0dacea92d26c31d453c58de2e99c178fee554166 (patch) | |
| tree | 5b8fd0c05385e02a586fbc136808821e603ea14f /hw/net/vmxnet3.c | |
| parent | ebc2327f0793deed845e2f7aeddf43b367c5c71c (diff) | |
| download | qemu-0dacea92d26c31d453c58de2e99c178fee554166.tar.gz | |
net: Transmit zero UDP checksum as 0xFFFF
The checksum algorithm used by IPv4, TCP and UDP allows a zero value
to be represented by either 0x0000 and 0xFFFF. But per RFC 768, a zero
UDP checksum must be transmitted as 0xFFFF because 0x0000 is a special
value meaning no checksum.
Substitute 0xFFFF whenever a checksum is computed as zero when
modifying a UDP datagram header. Doing this on IPv4 and TCP checksums
is unnecessary but legal. Add a wrapper for net_checksum_finish() that
makes the substitution.
(We can't just change net_checksum_finish(), as that function is also
used by receivers to verify checksums, and in that case the expected
value is always 0x0000.)
Signed-off-by: Ed Swierk <eswierk@skyportsystems.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
Diffstat (limited to 'hw/net/vmxnet3.c')
| -rw-r--r-- | hw/net/vmxnet3.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/hw/net/vmxnet3.c b/hw/net/vmxnet3.c index 8c4bae5394..cdc307dd04 100644 --- a/hw/net/vmxnet3.c +++ b/hw/net/vmxnet3.c @@ -972,7 +972,8 @@ static void vmxnet3_rx_need_csum_calculate(struct NetRxPkt *pkt, data = (uint8_t *)pkt_data + vhdr->csum_start; len = pkt_len - vhdr->csum_start; /* Put the checksum obtained into the packet */ - stw_be_p(data + vhdr->csum_offset, net_raw_checksum(data, len)); + stw_be_p(data + vhdr->csum_offset, + net_checksum_finish_nozero(net_checksum_add(len, data))); vhdr->flags &= ~VIRTIO_NET_HDR_F_NEEDS_CSUM; vhdr->flags |= VIRTIO_NET_HDR_F_DATA_VALID; |