Revert "VPP-1001 - update AF Packet Driver to for modern kernels"

Issues observed with specific kernel versions, e.g. stock Ubuntu 16.04
kernel.

This reverts commit 3eab064e3fadaf2a6a128f167ad04ca0319b4e17.

Change-Id: I24241f3b580df749fc686af3a319011ca035fb5e
Signed-off-by: Damjan Marion <damarion@cisco.com>
diff --git a/src/vnet/devices/af_packet/device.c b/src/vnet/devices/af_packet/device.c
index a48ae5c..e01b1c7 100644
--- a/src/vnet/devices/af_packet/device.c
+++ b/src/vnet/devices/af_packet/device.c
@@ -23,8 +23,6 @@
 #include <net/if.h>
 #include <net/if_arp.h>
 
-#include <linux/virtio_net.h>
-
 #include <vlib/vlib.h>
 #include <vlib/unix/unix.h>
 #include <vnet/ip/ip.h>
@@ -52,6 +50,7 @@
 #undef _
 };
 
+
 static u8 *
 format_af_packet_device_name (u8 * s, va_list * args)
 {
@@ -77,23 +76,6 @@
   return s;
 }
 
-
-static_always_inline void
-af_packet_buffer_tx_offload (vlib_buffer_t * b, struct virtio_net_hdr *vhdr)
-{
-  /* For now - just mark the data as valid,
-   * DPDK csums on input, tap presently operates in legacy
-   * compatibility mode where the kernel checksums CSUM_PARTIAL
-   * for it and we have fixed the af_packet input
-   *
-   * In the future, locally originated frames, etc can be made
-   * to fit this convention so that they are not checksummed
-   * unless needed.
-   **/
-  vhdr->flags = VIRTIO_NET_HDR_F_DATA_VALID;
-}
-
-
 static uword
 af_packet_interface_tx (vlib_main_t * vm,
 			vlib_node_runtime_t * node, vlib_frame_t * frame)
@@ -120,10 +102,6 @@
     {
       u32 len;
       u32 offset = 0;
-      if (PREDICT_TRUE ((apm->flags & AF_PACKET_USES_VNET_HEADERS) != 0))
-	{
-	  offset = sizeof (struct virtio_net_hdr);
-	}
       vlib_buffer_t *b0;
       n_left--;
       u32 bi = buffers[0];
@@ -141,12 +119,6 @@
       do
 	{
 	  b0 = vlib_get_buffer (vm, bi);
-	  if (PREDICT_TRUE ((apm->flags & AF_PACKET_USES_VNET_HEADERS) != 0))
-	    {
-	      u8 *vh =
-		(u8 *) tph + TPACKET_ALIGN (sizeof (struct tpacket2_hdr));
-	      af_packet_buffer_tx_offload (b0, (struct virtio_net_hdr *) vh);
-	    }
 	  len = b0->current_length;
 	  clib_memcpy ((u8 *) tph +
 		       TPACKET_ALIGN (sizeof (struct tpacket2_hdr)) + offset,