When an application sends with AF_PACKET and places a vlan header on
the raw packet; then the AF_PACKET needs to move the tag into the skb
so that it gets processed normally through the rest of the transmit
path.

This is particularly a problem on Hyper-V where the host only allows
vlan in the offload info.

Cc: xe-linux-exter...@cisco.com
Cc: Sriram Krishnan <srira...@cisco.com>
Signed-off-by: Sriram Krishnan <srira...@cisco.com>
---
 net/packet/af_packet.c | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 29bd405adbbd..10988639561e 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1857,15 +1857,35 @@ static int packet_rcv_spkt(struct sk_buff *skb, struct 
net_device *dev,
        return 0;
 }
 
-static void packet_parse_headers(struct sk_buff *skb, struct socket *sock)
+static int packet_parse_headers(struct sk_buff *skb, struct socket *sock)
 {
        if ((!skb->protocol || skb->protocol == htons(ETH_P_ALL)) &&
            sock->type == SOCK_RAW) {
+               __be16 ethertype;
+
                skb_reset_mac_header(skb);
+
+               ethertype = eth_hdr(skb)->h_proto;
+               /*
+                * If Vlan tag is present in the packet
+                *  move it to skb
+               */
+               if (eth_type_vlan(ethertype)) {
+                       int err;
+                       __be16 vlan_tci;
+
+                       err = __skb_vlan_pop(skb, &vlan_tci);
+                       if (unlikely(err))
+                               return err;
+
+                       __vlan_hwaccel_put_tag(skb, ethertype, vlan_tci);
+               }
+
                skb->protocol = dev_parse_header_protocol(skb);
        }
 
        skb_probe_transport_header(skb);
+       return 0;
 }
 
 /*
@@ -1987,7 +2007,9 @@ static int packet_sendmsg_spkt(struct socket *sock, 
struct msghdr *msg,
        if (unlikely(extra_len == 4))
                skb->no_fcs = 1;
 
-       packet_parse_headers(skb, sock);
+       err = packet_parse_headers(skb, sock);
+       if (err)
+               goto out_unlock;
 
        dev_queue_xmit(skb);
        rcu_read_unlock();
-- 
2.24.0

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