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author | Cédric Le Goater <clg@fr.ibm.com> | 2014-06-24 19:11:32 +0200 |
---|---|---|
committer | Michael S. Tsirkin <mst@redhat.com> | 2014-06-29 19:39:41 +0300 |
commit | 032a74a1c0fcdd5fd1c69e56126b4c857ee36611 (patch) | |
tree | 0a07110ca6192858747c5cf6adc8affab982be65 /hw | |
parent | a628fc8dae4c4a9a70f020ab65018a6e085a2088 (diff) | |
download | hqemu-032a74a1c0fcdd5fd1c69e56126b4c857ee36611.zip hqemu-032a74a1c0fcdd5fd1c69e56126b4c857ee36611.tar.gz |
virtio-net: byteswap virtio-net header
TCP connectivity fails when the guest has a different endianness.
The packets are silently dropped on the host by the tap backend
when they are read from user space because the endianness of the
virtio-net header is in the wrong order. These lines may appear
in the guest console:
[ 454.709327] skbuff: bad partial csum: csum=8704/4096 len=74
[ 455.702554] skbuff: bad partial csum: csum=8704/4096 len=74
The issue that got first spotted with a ppc64le PowerKVM guest,
but it also exists for the less common case of a x86_64 guest run
by a big-endian ppc64 TCG hypervisor.
Signed-off-by: Cédric Le Goater <clg@fr.ibm.com>
[ Ported from PowerKVM,
Greg Kurz <gkurz@linux.vnet.ibm.com> ]
Signed-off-by: Greg Kurz <gkurz@linux.vnet.ibm.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Diffstat (limited to 'hw')
-rw-r--r-- | hw/net/virtio-net.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c index e51d753..ea1a081 100644 --- a/hw/net/virtio-net.c +++ b/hw/net/virtio-net.c @@ -875,6 +875,14 @@ static int virtio_net_has_buffers(VirtIONetQueue *q, int bufsize) return 1; } +static void virtio_net_hdr_swap(struct virtio_net_hdr *hdr) +{ + tswap16s(&hdr->hdr_len); + tswap16s(&hdr->gso_size); + tswap16s(&hdr->csum_start); + tswap16s(&hdr->csum_offset); +} + /* dhclient uses AF_PACKET but doesn't pass auxdata to the kernel so * it never finds out that the packets don't have valid checksums. This * causes dhclient to get upset. Fedora's carried a patch for ages to @@ -910,6 +918,7 @@ static void receive_header(VirtIONet *n, const struct iovec *iov, int iov_cnt, void *wbuf = (void *)buf; work_around_broken_dhclient(wbuf, wbuf + n->host_hdr_len, size - n->host_hdr_len); + virtio_net_hdr_swap(wbuf); iov_from_buf(iov, iov_cnt, 0, buf, sizeof(struct virtio_net_hdr)); } else { struct virtio_net_hdr hdr = { @@ -1118,6 +1127,14 @@ static int32_t virtio_net_flush_tx(VirtIONetQueue *q) exit(1); } + if (n->has_vnet_hdr) { + if (out_sg[0].iov_len < n->guest_hdr_len) { + error_report("virtio-net header incorrect"); + exit(1); + } + virtio_net_hdr_swap((void *) out_sg[0].iov_base); + } + /* * If host wants to see the guest header as is, we can * pass it on unchanged. Otherwise, copy just the parts |