macvtap: fix network header pointer for VLAN tagged pkts

Network header is set with offset ETH_HLEN but it is not true for VLAN
(multiple-)tagged and results in checksum issues in lower devices.

v2: leave skb->protocol untouched (thx Vlad), comment added
v3: moved after skb_probe_transport_header() call (thx Toshiaki)

Signed-off-by: Ivan Vecera <ivecera@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 3b933bb5a8d5084208c2a9903ab44317cae5d146..edd77342773a8d4ef0713717adfa5bcf6bdf44f7 100644 (file)
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -719,6 +719,7 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
        struct virtio_net_hdr vnet_hdr = { 0 };
        int vnet_hdr_len = 0;
        int copylen = 0;
+       int depth;
        bool zerocopy = false;
        size_t linear;
        ssize_t n;
@@ -804,6 +805,12 @@ static ssize_t macvtap_get_user(struct macvtap_queue *q, struct msghdr *m,
 
        skb_probe_transport_header(skb, ETH_HLEN);
 
+       /* Move network header to the right position for VLAN tagged packets */
+       if ((skb->protocol == htons(ETH_P_8021Q) ||
+            skb->protocol == htons(ETH_P_8021AD)) &&
+           __vlan_get_protocol(skb, skb->protocol, &depth) != 0)
+               skb_set_network_header(skb, depth);
+
        rcu_read_lock();
        vlan = rcu_dereference(q->vlan);
        /* copy skb_ubuf_info for callback when skb has no error */