devices: add support for offloads

Type: improvement

This patch adds support for:
  1) GSO
  2) checksum offload

Signed-off-by: Mohsin Kazmi <sykazmi@cisco.com>
Change-Id: Ib00629888c62da04d58db36ce021993769e736c9

5 files changed, 301 insertions, 117 deletions

diff --git a/src/vnet/devices/af_packet/FEATURE.yaml b/src/vnet/devices/af_packet/FEATURE.yaml
index 25d8b2b5964..4a11ea2beb5 100644
--- a/src/vnet/devices/af_packet/FEATURE.yaml
+++ b/src/vnet/devices/af_packet/FEATURE.yaml
@@ -3,6 +3,7 @@ name: host-interface Device AF_PACKET
 maintainer: Damjan Marion <damarion@cisco.com>
 features:
   - L4 checksum offload
+  - GSO offload
 description: "Create a host interface that will attach to a linux AF_PACKET
               interface, one side of a veth pair. The veth pair must
               already exist. Once created, a new host interface will
diff --git a/src/vnet/devices/af_packet/af_packet.c b/src/vnet/devices/af_packet/af_packet.c
index 60eadf2b0dc..4fb54637a67 100644
--- a/src/vnet/devices/af_packet/af_packet.c
+++ b/src/vnet/devices/af_packet/af_packet.c
@@ -44,7 +44,7 @@ VNET_HW_INTERFACE_CLASS (af_packet_ip_device_hw_interface_class, static) = {
 };
 
 #define AF_PACKET_DEFAULT_TX_FRAMES_PER_BLOCK 1024
-#define AF_PACKET_DEFAULT_TX_FRAME_SIZE	      (2048 * 5)
+#define AF_PACKET_DEFAULT_TX_FRAME_SIZE	      (2048 * 33) // GSO packet of 64KB
 #define AF_PACKET_TX_BLOCK_NR		1
 
 #define AF_PACKET_DEFAULT_RX_FRAMES_PER_BLOCK 256
@@ -130,7 +130,7 @@ is_bridge (const u8 * host_if_name)
 static int
 create_packet_v3_sock (int host_if_index, tpacket_req3_t *rx_req,
 		       tpacket_req3_t *tx_req, int *fd, u8 **ring,
-		       u32 *hdrlen_ptr)
+		       u32 *hdrlen_ptr, u8 *is_cksum_gso_enabled)
 {
   af_packet_main_t *apm = &af_packet_main;
   struct sockaddr_ll sll;
@@ -198,6 +198,17 @@ create_packet_v3_sock (int host_if_index, tpacket_req3_t *rx_req,
       goto error;
     }
 
+  int opt2 = 1;
+  if (setsockopt (*fd, SOL_PACKET, PACKET_VNET_HDR, &opt2, sizeof (opt2)) < 0)
+    {
+      vlib_log_debug (
+	apm->log_class,
+	"Failed to set packet vnet hdr error handling option: %s (errno %d)",
+	strerror (errno), errno);
+    }
+  else
+    *is_cksum_gso_enabled = 1;
+
 #if defined(PACKET_QDISC_BYPASS)
   /* Introduced with Linux 3.14 so the ifdef should eventually be removed  */
   if (setsockopt (*fd, SOL_PACKET, PACKET_QDISC_BYPASS, &opt, sizeof (opt)) <
@@ -263,6 +274,7 @@ af_packet_create_if (af_packet_create_if_arg_t *arg)
   vnet_sw_interface_t *sw;
   vlib_thread_main_t *tm = vlib_get_thread_main ();
   vnet_main_t *vnm = vnet_get_main ();
+  vnet_hw_if_caps_t caps = VNET_HW_IF_CAP_INT_MODE;
   uword *p;
   uword if_index;
   u8 *host_if_name_dup = 0;
@@ -271,6 +283,7 @@ af_packet_create_if (af_packet_create_if_arg_t *arg)
   u32 rx_frame_size, tx_frame_size;
   u32 hdrlen = 0;
   u32 i = 0;
+  u8 is_cksum_gso_enabled = 0;
 
   p = mhash_get (&apm->if_index_by_host_if_name, arg->host_if_name);
   if (p)
@@ -365,8 +378,8 @@ af_packet_create_if (af_packet_create_if_arg_t *arg)
       fd2 = -1;
     }
 
-  ret =
-    create_packet_v3_sock (host_if_index, rx_req, tx_req, &fd, &ring, &hdrlen);
+  ret = create_packet_v3_sock (host_if_index, rx_req, tx_req, &fd, &ring,
+			       &hdrlen, &is_cksum_gso_enabled);
 
   if (ret != 0)
     goto error;
@@ -405,6 +418,7 @@ af_packet_create_if (af_packet_create_if_arg_t *arg)
   apif->next_rx_block = 0;
   apif->mode = arg->mode;
   apif->hdrlen = hdrlen;
+  apif->is_cksum_gso_enabled = is_cksum_gso_enabled;
 
   ret = af_packet_read_mtu (apif);
   if (ret != 0)
@@ -450,7 +464,11 @@ af_packet_create_if (af_packet_create_if_arg_t *arg)
   apif->queue_index = vnet_hw_if_register_rx_queue (vnm, apif->hw_if_index, 0,
 						    VNET_HW_IF_RXQ_THREAD_ANY);
 
-  vnet_hw_if_set_caps (vnm, apif->hw_if_index, VNET_HW_IF_CAP_INT_MODE);
+  if (apif->is_cksum_gso_enabled)
+    caps |= VNET_HW_IF_CAP_TCP_GSO | VNET_HW_IF_CAP_TX_IP4_CKSUM |
+	    VNET_HW_IF_CAP_TX_TCP_CKSUM | VNET_HW_IF_CAP_TX_UDP_CKSUM;
+
+  vnet_hw_if_set_caps (vnm, apif->hw_if_index, caps);
   vnet_hw_interface_set_flags (vnm, apif->hw_if_index,
 			       VNET_HW_INTERFACE_FLAG_LINK_UP);
 
@@ -554,20 +572,7 @@ af_packet_delete_if (u8 *host_if_name)
 int
 af_packet_set_l4_cksum_offload (u32 sw_if_index, u8 set)
 {
-  vnet_main_t *vnm = vnet_get_main ();
-  vnet_hw_interface_t *hw;
-  vnet_hw_if_caps_t caps =
-    VNET_HW_IF_CAP_TX_TCP_CKSUM | VNET_HW_IF_CAP_TX_UDP_CKSUM;
-  hw = vnet_get_sup_hw_interface (vnm, sw_if_index);
-
-  if (hw->dev_class_index != af_packet_device_class.index)
-    return VNET_API_ERROR_INVALID_INTERFACE;
-
-  if (set)
-    vnet_hw_if_set_caps (vnm, hw->hw_if_index, caps);
-  else
-    vnet_hw_if_unset_caps (vnm, hw->hw_if_index, caps);
-
+  // deprecated ...
   return 0;
 }
 
diff --git a/src/vnet/devices/af_packet/af_packet.h b/src/vnet/devices/af_packet/af_packet.h
index ed3f10bb092..dd38e1bb266 100644
--- a/src/vnet/devices/af_packet/af_packet.h
+++ b/src/vnet/devices/af_packet/af_packet.h
@@ -49,6 +49,7 @@ typedef struct
   tpacket_req3_t *tx_req;
   u8 **rx_ring;
   u8 **tx_ring;
+  u8 is_cksum_gso_enabled;
   u32 hdrlen;
   u32 hw_if_index;
   u32 sw_if_index;
diff --git a/src/vnet/devices/af_packet/device.c b/src/vnet/devices/af_packet/device.c
index 23b18832cc8..1aa1e0823c1 100644
--- a/src/vnet/devices/af_packet/device.c
+++ b/src/vnet/devices/af_packet/device.c
@@ -27,8 +27,14 @@
 #include <vlib/unix/unix.h>
 #include <vnet/ip/ip.h>
 #include <vnet/ethernet/ethernet.h>
+#include <vnet/ip/ip4_packet.h>
+#include <vnet/ip/ip6_packet.h>
+#include <vnet/ip/ip_psh_cksum.h>
+#include <vnet/tcp/tcp_packet.h>
+#include <vnet/udp/udp_packet.h>
 
 #include <vnet/devices/af_packet/af_packet.h>
+#include <vnet/devices/virtio/virtio_std.h>
 
 #define foreach_af_packet_tx_func_error               \
 _(FRAME_NOT_READY, "tx frame not ready")              \
@@ -100,7 +106,7 @@ format_af_packet_device (u8 * s, va_list * args)
   int n_send_req = 0, n_avail = 0, n_sending = 0, n_tot = 0, n_wrong = 0;
   do
     {
-      tph = (struct tpacket3_hdr *) (tx_block_start + tx_frame * tx_frame_sz);
+      tph = (tpacket3_hdr_t *) (tx_block_start + tx_frame * tx_frame_sz);
       tx_frame = (tx_frame + 1) % tx_frame_nr;
       if (tph->tp_status == 0)
 	n_avail++;
@@ -128,6 +134,93 @@ format_af_packet_tx_trace (u8 * s, va_list * args)
   return s;
 }
 
+static_always_inline void
+fill_gso_offload (vlib_buffer_t *b0, vnet_virtio_net_hdr_t *vnet_hdr)
+{
+  vnet_buffer_oflags_t oflags = vnet_buffer (b0)->oflags;
+  if (b0->flags & VNET_BUFFER_F_IS_IP4)
+    {
+      ip4_header_t *ip4;
+      vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
+      vnet_hdr->gso_size = vnet_buffer2 (b0)->gso_size;
+      vnet_hdr->hdr_len =
+	vnet_buffer (b0)->l4_hdr_offset + vnet_buffer2 (b0)->gso_l4_hdr_sz;
+      vnet_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
+      vnet_hdr->csum_start = vnet_buffer (b0)->l4_hdr_offset; // 0x22;
+      vnet_hdr->csum_offset = STRUCT_OFFSET_OF (tcp_header_t, checksum);
+      ip4 = (ip4_header_t *) (vlib_buffer_get_current (b0) +
+			      vnet_buffer (b0)->l3_hdr_offset);
+      if (oflags & VNET_BUFFER_OFFLOAD_F_IP_CKSUM)
+	ip4->checksum = ip4_header_checksum (ip4);
+    }
+  else if (b0->flags & VNET_BUFFER_F_IS_IP6)
+    {
+      vnet_hdr->gso_type = VIRTIO_NET_HDR_GSO_TCPV6;
+      vnet_hdr->gso_size = vnet_buffer2 (b0)->gso_size;
+      vnet_hdr->hdr_len =
+	vnet_buffer (b0)->l4_hdr_offset + vnet_buffer2 (b0)->gso_l4_hdr_sz;
+      vnet_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
+      vnet_hdr->csum_start = vnet_buffer (b0)->l4_hdr_offset; // 0x36;
+      vnet_hdr->csum_offset = STRUCT_OFFSET_OF (tcp_header_t, checksum);
+    }
+}
+
+static_always_inline void
+fill_cksum_offload (vlib_buffer_t *b0, vnet_virtio_net_hdr_t *vnet_hdr)
+{
+  vnet_buffer_oflags_t oflags = vnet_buffer (b0)->oflags;
+  if (b0->flags & VNET_BUFFER_F_IS_IP4)
+    {
+      ip4_header_t *ip4;
+      ip4 = (ip4_header_t *) (vlib_buffer_get_current (b0) +
+			      vnet_buffer (b0)->l3_hdr_offset);
+      if (oflags & VNET_BUFFER_OFFLOAD_F_IP_CKSUM)
+	ip4->checksum = ip4_header_checksum (ip4);
+      vnet_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
+      vnet_hdr->csum_start = 0x22;
+      if (oflags & VNET_BUFFER_OFFLOAD_F_TCP_CKSUM)
+	{
+	  tcp_header_t *tcp =
+	    (tcp_header_t *) (vlib_buffer_get_current (b0) +
+			      vnet_buffer (b0)->l4_hdr_offset);
+	  tcp->checksum = ip4_pseudo_header_cksum (ip4);
+	  vnet_hdr->csum_offset = STRUCT_OFFSET_OF (tcp_header_t, checksum);
+	}
+      else if (oflags & VNET_BUFFER_OFFLOAD_F_UDP_CKSUM)
+	{
+	  udp_header_t *udp =
+	    (udp_header_t *) (vlib_buffer_get_current (b0) +
+			      vnet_buffer (b0)->l4_hdr_offset);
+	  udp->checksum = ip4_pseudo_header_cksum (ip4);
+	  vnet_hdr->csum_offset = STRUCT_OFFSET_OF (udp_header_t, checksum);
+	}
+    }
+  else if (b0->flags & VNET_BUFFER_F_IS_IP6)
+    {
+      ip6_header_t *ip6;
+      vnet_hdr->flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
+      vnet_hdr->csum_start = 0x36;
+      ip6 = (ip6_header_t *) (vlib_buffer_get_current (b0) +
+			      vnet_buffer (b0)->l3_hdr_offset);
+      if (oflags & VNET_BUFFER_OFFLOAD_F_TCP_CKSUM)
+	{
+	  tcp_header_t *tcp =
+	    (tcp_header_t *) (vlib_buffer_get_current (b0) +
+			      vnet_buffer (b0)->l4_hdr_offset);
+	  tcp->checksum = ip6_pseudo_header_cksum (ip6);
+	  vnet_hdr->csum_offset = STRUCT_OFFSET_OF (tcp_header_t, checksum);
+	}
+      else if (oflags & VNET_BUFFER_OFFLOAD_F_UDP_CKSUM)
+	{
+	  udp_header_t *udp =
+	    (udp_header_t *) (vlib_buffer_get_current (b0) +
+			      vnet_buffer (b0)->l4_hdr_offset);
+	  udp->checksum = ip6_pseudo_header_cksum (ip6);
+	  vnet_hdr->csum_offset = STRUCT_OFFSET_OF (udp_header_t, checksum);
+	}
+    }
+}
+
 VNET_DEVICE_CLASS_TX_FN (af_packet_device_class) (vlib_main_t * vm,
 						  vlib_node_runtime_t * node,
 						  vlib_frame_t * frame)
@@ -147,17 +240,20 @@ VNET_DEVICE_CLASS_TX_FN (af_packet_device_class) (vlib_main_t * vm,
   u32 tx_frame = apif->next_tx_frame;
   tpacket3_hdr_t *tph;
   u32 frame_not_ready = 0;
+  u8 is_cksum_gso_enabled = (apif->is_cksum_gso_enabled == 1) ? 1 : 0;
 
   while (n_left)
     {
       u32 len;
+      vnet_virtio_net_hdr_t *vnet_hdr = 0;
       u32 offset = 0;
-      vlib_buffer_t *b0;
-      n_left--;
+      vlib_buffer_t *b0 = 0;
       u32 bi = buffers[0];
+
+      n_left--;
       buffers++;
 
-      tph = (struct tpacket3_hdr *) (block_start + tx_frame * frame_size);
+      tph = (tpacket3_hdr_t *) (block_start + tx_frame * frame_size);
       if (PREDICT_FALSE (tph->tp_status &
 			 (TP_STATUS_SEND_REQUEST | TP_STATUS_SENDING)))
 	{
@@ -165,17 +261,38 @@ VNET_DEVICE_CLASS_TX_FN (af_packet_device_class) (vlib_main_t * vm,
 	  goto next;
 	}
 
-      do
+      b0 = vlib_get_buffer (vm, bi);
+
+      if (is_cksum_gso_enabled)
+	{
+	  vnet_hdr =
+	    (vnet_virtio_net_hdr_t *) ((u8 *) tph + TPACKET_ALIGN (sizeof (
+						      tpacket3_hdr_t)));
+
+	  clib_memset_u8 (vnet_hdr, 0, sizeof (vnet_virtio_net_hdr_t));
+	  offset = sizeof (vnet_virtio_net_hdr_t);
+
+	  if (b0->flags & VNET_BUFFER_F_GSO)
+	    fill_gso_offload (b0, vnet_hdr);
+	  else if (b0->flags & VNET_BUFFER_F_OFFLOAD)
+	    fill_cksum_offload (b0, vnet_hdr);
+	}
+
+      len = b0->current_length;
+      clib_memcpy_fast ((u8 *) tph + TPACKET_ALIGN (sizeof (tpacket3_hdr_t)) +
+			  offset,
+			vlib_buffer_get_current (b0), len);
+      offset += len;
+
+      while (b0->flags & VLIB_BUFFER_NEXT_PRESENT)
 	{
-	  b0 = vlib_get_buffer (vm, bi);
+	  b0 = vlib_get_buffer (vm, b0->next_buffer);
 	  len = b0->current_length;
-	  clib_memcpy_fast (
-	    (u8 *) tph + TPACKET_ALIGN (sizeof (struct tpacket3_hdr)) + offset,
-	    vlib_buffer_get_current (b0), len);
+	  clib_memcpy_fast ((u8 *) tph +
+			      TPACKET_ALIGN (sizeof (tpacket3_hdr_t)) + offset,
+			    vlib_buffer_get_current (b0), len);
 	  offset += len;
 	}
-      while ((bi =
-	      (b0->flags & VLIB_BUFFER_NEXT_PRESENT) ? b0->next_buffer : 0));
 
       tph->tp_len = tph->tp_snaplen = offset;
       tph->tp_status = TP_STATUS_SEND_REQUEST;
diff --git a/src/vnet/devices/af_packet/node.c b/src/vnet/devices/af_packet/node.c
index 229e0501af7..a42e3e07cd9 100644
--- a/src/vnet/devices/af_packet/node.c
+++ b/src/vnet/devices/af_packet/node.c
@@ -28,6 +28,7 @@
 #include <vnet/ethernet/packet.h>
 
 #include <vnet/devices/af_packet/af_packet.h>
+#include <vnet/devices/virtio/virtio_std.h>
 
 #define foreach_af_packet_input_error \
   _(PARTIAL_PKT, "partial packet")
@@ -51,10 +52,11 @@ typedef struct
   u32 next_index;
   u32 hw_if_index;
   int block;
-  u32 num_pkts;
+  u32 pkt_num;
   void *block_start;
   block_desc_t bd;
   tpacket3_hdr_t tph;
+  vnet_virtio_net_hdr_t vnet_hdr;
 } af_packet_input_trace_t;
 
 static u8 *
@@ -68,12 +70,10 @@ format_af_packet_input_trace (u8 * s, va_list * args)
   s = format (s, "af_packet: hw_if_index %d next-index %d",
 	      t->hw_if_index, t->next_index);
 
-  s = format (s,
-	      "\n%Ublock %u:\n%Uaddress %p version %u seq_num %lu"
-	      " num_pkts %u",
-	      format_white_space, indent + 2, t->block, format_white_space,
-	      indent + 4, t->block_start, t->bd.version, t->bd.hdr.bh1.seq_num,
-	      t->num_pkts);
+  s = format (
+    s, "\n%Ublock %u:\n%Uaddress %p version %u seq_num %lu pkt_num %u",
+    format_white_space, indent + 2, t->block, format_white_space, indent + 4,
+    t->block_start, t->bd.version, t->bd.hdr.bh1.seq_num, t->pkt_num);
   s =
     format (s,
 	    "\n%Utpacket3_hdr:\n%Ustatus 0x%x len %u snaplen %u mac %u net %u"
@@ -91,16 +91,21 @@ format_af_packet_input_trace (u8 * s, va_list * args)
 	    t->tph.hv1.tp_vlan_tpid
 #endif
     );
+
+  s = format (s,
+	      "\n%Uvnet-hdr:\n%Uflags 0x%02x gso_type 0x%02x hdr_len %u"
+	      "\n%Ugso_size %u csum_start %u csum_offset %u",
+	      format_white_space, indent + 2, format_white_space, indent + 4,
+	      t->vnet_hdr.flags, t->vnet_hdr.gso_type, t->vnet_hdr.hdr_len,
+	      format_white_space, indent + 4, t->vnet_hdr.gso_size,
+	      t->vnet_hdr.csum_start, t->vnet_hdr.csum_offset);
   return s;
 }
 
 always_inline void
-buffer_add_to_chain (vlib_main_t * vm, u32 bi, u32 first_bi, u32 prev_bi)
+buffer_add_to_chain (vlib_buffer_t *b, vlib_buffer_t *first_b,
+		     vlib_buffer_t *prev_b, u32 bi)
 {
-  vlib_buffer_t *b = vlib_get_buffer (vm, bi);
-  vlib_buffer_t *first_b = vlib_get_buffer (vm, first_bi);
-  vlib_buffer_t *prev_b = vlib_get_buffer (vm, prev_bi);
-
   /* update first buffer */
   first_b->total_length_not_including_first_buffer += b->current_length;
 
@@ -109,11 +114,11 @@ buffer_add_to_chain (vlib_main_t * vm, u32 bi, u32 first_bi, u32 prev_bi)
   prev_b->flags |= VLIB_BUFFER_NEXT_PRESENT;
 
   /* update current buffer */
-  b->next_buffer = 0;
+  b->next_buffer = ~0;
 }
 
 static_always_inline void
-fill_gso_buffer_flags (vlib_buffer_t *b, u32 gso_size, u8 l4_hdr_sz)
+fill_gso_offload (vlib_buffer_t *b, u32 gso_size, u8 l4_hdr_sz)
 {
   b->flags |= VNET_BUFFER_F_GSO;
   vnet_buffer2 (b)->gso_size = gso_size;
@@ -121,43 +126,66 @@ fill_gso_buffer_flags (vlib_buffer_t *b, u32 gso_size, u8 l4_hdr_sz)
 }
 
 static_always_inline void
-mark_tcp_udp_cksum_calc (vlib_buffer_t *b, u8 *l4_hdr_sz)
+fill_cksum_offload (vlib_buffer_t *b, u8 *l4_hdr_sz, u8 is_ip)
 {
-  ethernet_header_t *eth = vlib_buffer_get_current (b);
   vnet_buffer_oflags_t oflags = 0;
-  if (clib_net_to_host_u16 (eth->type) == ETHERNET_TYPE_IP4)
+  u16 l2hdr_sz = 0;
+  u16 ethertype = 0;
+  u8 l4_proto = 0;
+
+  if (is_ip)
     {
-      ip4_header_t *ip4 =
-	(vlib_buffer_get_current (b) + sizeof (ethernet_header_t));
-      b->flags |= VNET_BUFFER_F_IS_IP4;
-      if (ip4->protocol == IP_PROTOCOL_TCP)
+      switch (b->data[0] & 0xf0)
 	{
-	  oflags |= VNET_BUFFER_OFFLOAD_F_TCP_CKSUM;
-	  tcp_header_t *tcp = (tcp_header_t *) (vlib_buffer_get_current (b) +
-						sizeof (ethernet_header_t) +
-						ip4_header_bytes (ip4));
-	  *l4_hdr_sz = tcp_header_bytes (tcp);
+	case 0x40:
+	  ethertype = ETHERNET_TYPE_IP4;
+	  break;
+	case 0x60:
+	  ethertype = ETHERNET_TYPE_IP6;
+	  break;
 	}
-      else if (ip4->protocol == IP_PROTOCOL_UDP)
+    }
+  else
+    {
+      ethernet_header_t *eth = vlib_buffer_get_current (b);
+      ethertype = clib_net_to_host_u16 (eth->type);
+      l2hdr_sz = sizeof (ethernet_header_t);
+      if (ethernet_frame_is_tagged (ethertype))
 	{
-	  oflags |= VNET_BUFFER_OFFLOAD_F_UDP_CKSUM;
-	  udp_header_t *udp = (udp_header_t *) (vlib_buffer_get_current (b) +
-						sizeof (ethernet_header_t) +
-						ip4_header_bytes (ip4));
-	  *l4_hdr_sz = sizeof (*udp);
+	  ethernet_vlan_header_t *vlan = (ethernet_vlan_header_t *) (eth + 1);
+
+	  ethertype = clib_net_to_host_u16 (vlan->type);
+	  l2hdr_sz += sizeof (*vlan);
+	  if (ethertype == ETHERNET_TYPE_VLAN)
+	    {
+	      vlan++;
+	      ethertype = clib_net_to_host_u16 (vlan->type);
+	      l2hdr_sz += sizeof (*vlan);
+	    }
 	}
-      vnet_buffer (b)->l3_hdr_offset = sizeof (ethernet_header_t);
-      vnet_buffer (b)->l4_hdr_offset =
-	sizeof (ethernet_header_t) + ip4_header_bytes (ip4);
-      if (oflags)
-	vnet_buffer_offload_flags_set (b, oflags);
     }
-  else if (clib_net_to_host_u16 (eth->type) == ETHERNET_TYPE_IP6)
+
+  vnet_buffer (b)->l2_hdr_offset = 0;
+  vnet_buffer (b)->l3_hdr_offset = l2hdr_sz;
+
+  if (ethertype == ETHERNET_TYPE_IP4)
+    {
+      ip4_header_t *ip4 = (vlib_buffer_get_current (b) + l2hdr_sz);
+      vnet_buffer (b)->l4_hdr_offset = l2hdr_sz + ip4_header_bytes (ip4);
+      b->flags |= (VNET_BUFFER_F_IS_IP4 | VNET_BUFFER_F_L2_HDR_OFFSET_VALID |
+		   VNET_BUFFER_F_L3_HDR_OFFSET_VALID |
+		   VNET_BUFFER_F_L4_HDR_OFFSET_VALID);
+
+      l4_proto = ip4->protocol;
+    }
+  else if (ethertype == ETHERNET_TYPE_IP6)
     {
-      ip6_header_t *ip6 =
-	(vlib_buffer_get_current (b) + sizeof (ethernet_header_t));
-      b->flags |= VNET_BUFFER_F_IS_IP6;
+      ip6_header_t *ip6 = (vlib_buffer_get_current (b) + l2hdr_sz);
+      b->flags |= (VNET_BUFFER_F_IS_IP6 | VNET_BUFFER_F_L2_HDR_OFFSET_VALID |
+		   VNET_BUFFER_F_L3_HDR_OFFSET_VALID |
+		   VNET_BUFFER_F_L4_HDR_OFFSET_VALID);
       u16 ip6_hdr_len = sizeof (ip6_header_t);
+
       if (ip6_ext_hdr (ip6->protocol))
 	{
 	  ip6_ext_header_t *p = (void *) (ip6 + 1);
@@ -167,34 +195,34 @@ mark_tcp_udp_cksum_calc (vlib_buffer_t *b, u8 *l4_hdr_sz)
 	      ip6_hdr_len += ip6_ext_header_len (p);
 	      p = ip6_ext_next_header (p);
 	    }
+	  l4_proto = p->next_hdr;
 	}
-      if (ip6->protocol == IP_PROTOCOL_TCP)
-	{
-	  oflags |= VNET_BUFFER_OFFLOAD_F_TCP_CKSUM;
-	  tcp_header_t *tcp =
-	    (tcp_header_t *) (vlib_buffer_get_current (b) +
-			      sizeof (ethernet_header_t) + ip6_hdr_len);
-	  *l4_hdr_sz = tcp_header_bytes (tcp);
-	}
-      else if (ip6->protocol == IP_PROTOCOL_UDP)
-	{
-	  oflags |= VNET_BUFFER_OFFLOAD_F_UDP_CKSUM;
-	  udp_header_t *udp =
-	    (udp_header_t *) (vlib_buffer_get_current (b) +
-			      sizeof (ethernet_header_t) + ip6_hdr_len);
-	  *l4_hdr_sz = sizeof (*udp);
-	}
-      vnet_buffer (b)->l3_hdr_offset = sizeof (ethernet_header_t);
-      vnet_buffer (b)->l4_hdr_offset =
-	sizeof (ethernet_header_t) + ip6_hdr_len;
-      if (oflags)
-	vnet_buffer_offload_flags_set (b, oflags);
+      else
+	l4_proto = ip6->protocol;
+      vnet_buffer (b)->l4_hdr_offset = l2hdr_sz + ip6_hdr_len;
+    }
+
+  if (l4_proto == IP_PROTOCOL_TCP)
+    {
+      oflags |= VNET_BUFFER_OFFLOAD_F_TCP_CKSUM;
+      tcp_header_t *tcp = (tcp_header_t *) (vlib_buffer_get_current (b) +
+					    vnet_buffer (b)->l4_hdr_offset);
+      *l4_hdr_sz = tcp_header_bytes (tcp);
+    }
+  else if (l4_proto == IP_PROTOCOL_UDP)
+    {
+      oflags |= VNET_BUFFER_OFFLOAD_F_UDP_CKSUM;
+      *l4_hdr_sz = sizeof (udp_header_t);
     }
+
+  if (oflags)
+    vnet_buffer_offload_flags_set (b, oflags);
 }
 
 always_inline uword
-af_packet_device_input_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
-			   vlib_frame_t * frame, af_packet_if_t * apif)
+af_packet_device_input_fn (vlib_main_t *vm, vlib_node_runtime_t *node,
+			   vlib_frame_t *frame, af_packet_if_t *apif,
+			   u8 is_cksum_gso_enabled)
 {
   af_packet_main_t *apm = &af_packet_main;
   tpacket3_hdr_t *tph;
@@ -210,19 +238,16 @@ af_packet_device_input_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
   u32 thread_index = vm->thread_index;
   u32 n_buffer_bytes = vlib_buffer_get_default_data_size (vm);
   u32 min_bufs = apif->rx_req->tp_frame_size / n_buffer_bytes;
-  u32 eth_header_size = 0;
   u32 num_pkts = 0;
   u32 rx_frame_offset = 0;
   block_desc_t *bd = 0;
   vlib_buffer_t bt;
+  u8 is_ip = (apif->mode == AF_PACKET_IF_MODE_IP);
 
-  if (apif->mode == AF_PACKET_IF_MODE_IP)
-    {
-      next_index = VNET_DEVICE_INPUT_NEXT_IP4_INPUT;
-    }
+  if (is_ip)
+    next_index = VNET_DEVICE_INPUT_NEXT_IP4_INPUT;
   else
     {
-      eth_header_size = sizeof (ethernet_header_t);
       next_index = VNET_DEVICE_INPUT_NEXT_ETHERNET_INPUT;
       if (PREDICT_FALSE (apif->per_interface_next_index != ~0))
 	next_index = apif->per_interface_next_index;
@@ -257,10 +282,11 @@ af_packet_device_input_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
 
       while (num_pkts && (n_free_bufs > min_bufs))
 	{
-	  vlib_buffer_t *b0 = 0, *first_b0 = 0;
 	  u32 next0 = next_index;
 	  u32 n_left_to_next;
+
 	  vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);
+
 	  while (num_pkts && n_left_to_next && (n_free_bufs > min_bufs))
 	    {
 	      tph = (tpacket3_hdr_t *) (block_start + rx_frame_offset);
@@ -269,19 +295,36 @@ af_packet_device_input_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
 		CLIB_PREFETCH (block_start + rx_frame_offset +
 				 tph->tp_next_offset,
 			       2 * CLIB_CACHE_LINE_BYTES, LOAD);
+
+	      vlib_buffer_t *b0 = 0, *first_b0 = 0, *prev_b0 = 0;
+	      vnet_virtio_net_hdr_t *vnet_hdr = 0;
 	      u32 data_len = tph->tp_snaplen;
 	      u32 offset = 0;
-	      u32 bi0 = 0, first_bi0 = 0, prev_bi0;
+	      u32 bi0 = ~0, first_bi0 = ~0;
 	      u8 l4_hdr_sz = 0;
 
+	      if (is_cksum_gso_enabled)
+		vnet_hdr =
+		  (vnet_virtio_net_hdr_t *) ((u8 *) tph + tph->tp_mac -
+					     sizeof (vnet_virtio_net_hdr_t));
+
+	      if (PREDICT_FALSE (((data_len / n_buffer_bytes) + 1) >
+				 vec_len (apm->rx_buffers[thread_index])))
+		{
+		  vec_validate (apm->rx_buffers[thread_index],
+				VLIB_FRAME_SIZE + n_free_bufs - 1);
+		  n_free_bufs += vlib_buffer_alloc (
+		    vm, &apm->rx_buffers[thread_index][n_free_bufs],
+		    VLIB_FRAME_SIZE);
+		  _vec_len (apm->rx_buffers[thread_index]) = n_free_bufs;
+		}
+
 	      while (data_len)
 		{
 		  /* grab free buffer */
 		  u32 last_empty_buffer =
 		    vec_len (apm->rx_buffers[thread_index]) - 1;
-		  prev_bi0 = bi0;
 		  bi0 = apm->rx_buffers[thread_index][last_empty_buffer];
-		  b0 = vlib_get_buffer (vm, bi0);
 		  _vec_len (apm->rx_buffers[thread_index]) = last_empty_buffer;
 		  n_free_bufs--;
 
@@ -290,7 +333,10 @@ af_packet_device_input_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
 		    data_len > n_buffer_bytes ? n_buffer_bytes : data_len;
 		  u32 vlan_len = 0;
 		  u32 bytes_copied = 0;
+
+		  b0 = vlib_get_buffer (vm, bi0);
 		  b0->current_data = 0;
+
 		  /* Kernel removes VLAN headers, so reconstruct VLAN */
 		  if (PREDICT_FALSE (tph->tp_status & TP_STATUS_VLAN_VALID))
 		    {
@@ -328,20 +374,22 @@ af_packet_device_input_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
 		      vnet_buffer (b0)->sw_if_index[VLIB_RX] =
 			apif->sw_if_index;
 		      vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~0;
+		      first_b0 = b0;
 		      first_bi0 = bi0;
-		      first_b0 = vlib_get_buffer (vm, first_bi0);
-		      if (tph->tp_status & TP_STATUS_CSUMNOTREADY)
-			mark_tcp_udp_cksum_calc (first_b0, &l4_hdr_sz);
-		      /* This is a trade-off for GSO. As kernel isn't passing
-		       * us the GSO state or size, we guess it by comparing it
-		       * to the host MTU of the interface */
-		      if (tph->tp_snaplen > (apif->host_mtu + eth_header_size))
-			fill_gso_buffer_flags (first_b0, apif->host_mtu,
-					       l4_hdr_sz);
+		      if (is_cksum_gso_enabled)
+			{
+			  if (vnet_hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM)
+			    fill_cksum_offload (first_b0, &l4_hdr_sz, is_ip);
+			  if (vnet_hdr->gso_type & (VIRTIO_NET_HDR_GSO_TCPV4 |
+						    VIRTIO_NET_HDR_GSO_TCPV6))
+			    fill_gso_offload (first_b0, vnet_hdr->gso_size,
+					      l4_hdr_sz);
+			}
 		    }
 		  else
-		    buffer_add_to_chain (vm, bi0, first_bi0, prev_bi0);
+		    buffer_add_to_chain (b0, first_b0, prev_b0, bi0);
 
+		  prev_b0 = b0;
 		  offset += bytes_to_copy;
 		  data_len -= bytes_to_copy;
 		}
@@ -398,9 +446,15 @@ af_packet_device_input_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
 		  tr->hw_if_index = apif->hw_if_index;
 		  tr->block = block;
 		  tr->block_start = bd;
-		  tr->num_pkts = num_pkts;
+		  tr->pkt_num = bd->hdr.bh1.num_pkts - num_pkts;
 		  clib_memcpy_fast (&tr->bd, bd, sizeof (block_desc_t));
 		  clib_memcpy_fast (&tr->tph, tph, sizeof (tpacket3_hdr_t));
+		  if (is_cksum_gso_enabled)
+		    clib_memcpy_fast (&tr->vnet_hdr, vnet_hdr,
+				      sizeof (vnet_virtio_net_hdr_t));
+		  else
+		    clib_memset_u8 (&tr->vnet_hdr, 0,
+				    sizeof (vnet_virtio_net_hdr_t));
 		}
 
 	      /* enque and take next packet */
@@ -446,9 +500,15 @@ VLIB_NODE_FN (af_packet_input_node) (vlib_main_t * vm,
       af_packet_if_t *apif;
       apif = vec_elt_at_index (apm->interfaces, pv[i].dev_instance);
       if (apif->is_admin_up)
-	n_rx_packets += af_packet_device_input_fn (vm, node, frame, apif);
+	{
+	  if (apif->is_cksum_gso_enabled)
+	    n_rx_packets +=
+	      af_packet_device_input_fn (vm, node, frame, apif, 1);
+	  else
+	    n_rx_packets +=
+	      af_packet_device_input_fn (vm, node, frame, apif, 0);
+	}
     }
-
   return n_rx_packets;
 }