bnx2: Reinsert VLAN tag when necessary.

In certain cases when ASF or other management firmware is running, the
chip may be configured to always strip out the VLAN tag even when
VLAN acceleration is not enabled. This causes some VLAN tagged
packets to be received by the host stack without any knowledge that
the original packet was VLAN tagged.

We fix this by re-inserting the VLAN tag into the packet when necessary.

Signed-off-by: Michael Chan <[e-mail]>
Signed-off-by: Benjamin Li <[e-mail]>
Signed-off-by: Matt Carlson <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

drivers/net/bnx2.c

···
 		struct sw_bd *rx_buf;
 		struct sk_buff *skb;
 		dma_addr_t dma_addr;
+		u16 vtag = 0;
+		int hw_vlan __maybe_unused = 0;
 
 		sw_ring_cons = RX_RING_IDX(sw_cons);
 		sw_ring_prod = RX_RING_IDX(sw_prod);
···
 		if (len <= bp->rx_copy_thresh) {
 			struct sk_buff *new_skb;
 
-			new_skb = netdev_alloc_skb(bp->dev, len + 2);
+			new_skb = netdev_alloc_skb(bp->dev, len + 6);
 			if (new_skb == NULL) {
 				bnx2_reuse_rx_skb(bp, rxr, skb, sw_ring_cons,
 						  sw_ring_prod);
···
 
 			/* aligned copy */
 			skb_copy_from_linear_data_offset(skb,
-							 BNX2_RX_OFFSET - 2,
-				      new_skb->data, len + 2);
-			skb_reserve(new_skb, 2);
+							 BNX2_RX_OFFSET - 6,
+				      new_skb->data, len + 6);
+			skb_reserve(new_skb, 6);
 			skb_put(new_skb, len);
 
 			bnx2_reuse_rx_skb(bp, rxr, skb,
···
 		} else if (unlikely(bnx2_rx_skb(bp, rxr, skb, len, hdr_len,
 			   dma_addr, (sw_ring_cons << 16) | sw_ring_prod)))
 			goto next_rx;
+
+		if ((status & L2_FHDR_STATUS_L2_VLAN_TAG) &&
+		    !(bp->rx_mode & BNX2_EMAC_RX_MODE_KEEP_VLAN_TAG)) {
+			vtag = rx_hdr->l2_fhdr_vlan_tag;
+#ifdef BCM_VLAN
+			if (bp->vlgrp)
+				hw_vlan = 1;
+			else
+#endif
+			{
+				struct vlan_ethhdr *ve = (struct vlan_ethhdr *)
+					__skb_push(skb, 4);
+
+				memmove(ve, skb->data + 4, ETH_ALEN * 2);
+				ve->h_vlan_proto = htons(ETH_P_8021Q);
+				ve->h_vlan_TCI = htons(vtag);
+				len += 4;
+			}
+		}
 
 		skb->protocol = eth_type_trans(skb, bp->dev);
 
···
 		}
 
 #ifdef BCM_VLAN
-		if ((status & L2_FHDR_STATUS_L2_VLAN_TAG) && bp->vlgrp) {
-			vlan_hwaccel_receive_skb(skb, bp->vlgrp,
-				rx_hdr->l2_fhdr_vlan_tag);
-		}
+		if (hw_vlan)
+			vlan_hwaccel_receive_skb(skb, bp->vlgrp, vtag);
 		else
 #endif
 			netif_receive_skb(skb);