3.13.11.4 -stable review patch. If anyone has any objections, please let me know.
------------------ From: Vlad Yasevich <[email protected]> [ 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 <[email protected]> CC: Patrick McHardy <[email protected]> CC: Andrian Nord <[email protected]> CC: Eric Dumazet <[email protected]> CC: Michael S. Tsirkin <[email protected]> CC: Jason Wang <[email protected]> Signed-off-by: Vlad Yasevich <[email protected]> Acked-by: Jason Wang <[email protected]> Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Kamal Mostafa <[email protected]> --- drivers/net/macvtap.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c index 2a89da0..73ffad8 100644 --- a/drivers/net/macvtap.c +++ b/drivers/net/macvtap.c @@ -315,6 +315,15 @@ static int macvtap_forward(struct net_device *dev, struct sk_buff *skb) 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); } -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
