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authorVlad Yasevich <vyasevic@redhat.com>2014-04-29 10:09:50 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-05-31 13:20:36 -0700
commitbdccb452699c0da6df5538904bbf4847de1cf4fc (patch)
tree1891b917e02f89c09c15f1d2e67147b26623e0fe
parent987c76c0af87c57566bd9cb99e7a9f04fcd949be (diff)
mactap: Fix checksum errors for non-gso packets in bridge mode
[ Upstream commit cbdb04279ccaefcc702c8757757eea8ed76e50cf ] The following is a problematic configuration: VM1: virtio-net device connected to macvtap0@eth0 VM2: e1000 device connect to macvtap1@eth0 The problem is is that virtio-net supports checksum offloading and thus sends the packets to the host with CHECKSUM_PARTIAL set. On the other hand, e1000 does not support any acceleration. For small TCP packets (and this includes the 3-way handshake), e1000 ends up receiving packets that only have a partial checksum set. This causes TCP to fail checksum validation and to drop packets. As a result tcp connections can not be established. Commit 3e4f8b787370978733ca6cae452720a4f0c296b8 macvtap: Perform GSO on forwarding path. fixes this issue for large packets wthat will end up undergoing GSO. This commit adds a check for the non-GSO case and attempts to compute the checksum for partially checksummed packets in the non-GSO case. CC: Daniel Lezcano <daniel.lezcano@free.fr> CC: Patrick McHardy <kaber@trash.net> CC: Andrian Nord <nightnord@gmail.com> CC: Eric Dumazet <eric.dumazet@gmail.com> CC: Michael S. Tsirkin <mst@redhat.com> CC: Jason Wang <jasowang@redhat.com> Signed-off-by: Vlad Yasevich <vyasevic@redhat.com> Acked-by: Jason Wang <jasowang@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/net/macvtap.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index ff111a89e17f..3381c4f91a8c 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -322,6 +322,15 @@ static rx_handler_result_t macvtap_handle_frame(struct sk_buff **pskb)
segs = nskb;
}
} else {
+ /* If we receive a partial checksum and the tap side
+ * doesn't support checksum offload, compute the checksum.
+ * Note: it doesn't matter which checksum feature to
+ * check, we either support them all or none.
+ */
+ if (skb->ip_summed == CHECKSUM_PARTIAL &&
+ !(features & NETIF_F_ALL_CSUM) &&
+ skb_checksum_help(skb))
+ goto drop;
skb_queue_tail(&q->sk.sk_receive_queue, skb);
}