src/vnet/devices/virtio/node.c - fdio/vpp - Gitiles

 /*
  *------------------------------------------------------------------
  * Copyright (c) 2016 Cisco and/or its affiliates.
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at:
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  *------------------------------------------------------------------
  */

 #include <sys/types.h>
 #include <sys/stat.h>
 #include <fcntl.h>
 #include <net/if.h>
 #include <linux/if_tun.h>
 #include <sys/ioctl.h>
 #include <sys/eventfd.h>

 #include <vlib/vlib.h>
 #include <vlib/unix/unix.h>
 #include <vnet/ethernet/ethernet.h>
 #include <vnet/devices/devices.h>
 #include <vnet/feature/feature.h>
 #include <vnet/gso/gro_func.h>
 #include <vnet/ip/ip4_packet.h>
 #include <vnet/ip/ip6_packet.h>
 #include <vnet/udp/udp_packet.h>
 #include <vnet/devices/virtio/virtio.h>


 #define foreach_virtio_input_error \
   _(BUFFER_ALLOC, "buffer alloc error") \
   _(UNKNOWN, "unknown")

 typedef enum
 {
 #define _(f,s) VIRTIO_INPUT_ERROR_##f,
   foreach_virtio_input_error
 #undef _
     VIRTIO_INPUT_N_ERROR,
 } virtio_input_error_t;

 static char *virtio_input_error_strings[] = {
 #define _(n,s) s,
   foreach_virtio_input_error
 #undef _
 };

 typedef struct
 {
   u32 next_index;
   u32 hw_if_index;
   u16 ring;
   u16 len;
   virtio_net_hdr_v1_t hdr;
 } virtio_input_trace_t;

 static u8 *
 format_virtio_input_trace (u8 * s, va_list * args)
 {
   CLIB_UNUSED (vlib_main_t * vm) = va_arg (*args, vlib_main_t *);
   CLIB_UNUSED (vlib_node_t * node) = va_arg (*args, vlib_node_t *);
   virtio_input_trace_t *t = va_arg (*args, virtio_input_trace_t *);
   u32 indent = format_get_indent (s);

   s = format (s, "virtio: hw_if_index %d next-index %d vring %u len %u",
 	      t->hw_if_index, t->next_index, t->ring, t->len);
   s = format (s, "\n%Uhdr: flags 0x%02x gso_type 0x%02x hdr_len %u "
 	      "gso_size %u csum_start %u csum_offset %u num_buffers %u",
 	      format_white_space, indent + 2,
 	      t->hdr.flags, t->hdr.gso_type, t->hdr.hdr_len, t->hdr.gso_size,
 	      t->hdr.csum_start, t->hdr.csum_offset, t->hdr.num_buffers);
   return s;
 }

 static_always_inline void
 virtio_refill_vring (vlib_main_t * vm, virtio_if_t * vif,
 		     virtio_if_type_t type, virtio_vring_t * vring,
 		     const int hdr_sz, u32 node_index)
 {
   u16 used, next, avail, n_slots, n_refill;
   u16 sz = vring->size;
   u16 mask = sz - 1;

 more:
   used = vring->desc_in_use;

   if (sz - used < sz / 8)
     return;

   /* deliver free buffers in chunks of 64 */
   n_refill = clib_min (sz - used, 64);

   next = vring->desc_next;
   avail = vring->avail->idx;
   n_slots =
     vlib_buffer_alloc_to_ring_from_pool (vm, vring->buffers, next,
 					 vring->size, n_refill,
 					 vring->buffer_pool_index);

   if (PREDICT_FALSE (n_slots != n_refill))
     {
       vlib_error_count (vm, node_index,
 			VIRTIO_INPUT_ERROR_BUFFER_ALLOC, n_refill - n_slots);
       if (n_slots == 0)
 	return;
     }

   while (n_slots)
     {
       vring_desc_t *d = &vring->desc[next];;
       vlib_buffer_t *b = vlib_get_buffer (vm, vring->buffers[next]);
       /*
        * current_data may not be initialized with 0 and may contain
        * previous offset. Here we want to make sure, it should be 0
        * initialized.
        */
       b->current_data = -hdr_sz;
       memset (vlib_buffer_get_current (b), 0, hdr_sz);
       d->addr =
 	((type == VIRTIO_IF_TYPE_PCI) ? vlib_buffer_get_current_pa (vm,
 								    b) :
 	 pointer_to_uword (vlib_buffer_get_current (b)));
       d->len = vlib_buffer_get_default_data_size (vm) + hdr_sz;
       d->flags = VRING_DESC_F_WRITE;
       vring->avail->ring[avail & mask] = next;
       avail++;
       next = (next + 1) & mask;
       n_slots--;
       used++;
     }
   CLIB_MEMORY_STORE_BARRIER ();
   vring->avail->idx = avail;
   vring->desc_next = next;
   vring->desc_in_use = used;

   if ((vring->used->flags & VRING_USED_F_NO_NOTIFY) == 0)
     {
       virtio_kick (vm, vring, vif);
     }
   goto more;
 }

 static_always_inline void
 virtio_needs_csum (vlib_buffer_t * b0, virtio_net_hdr_v1_t * hdr,
 		   u8 * l4_proto, u8 * l4_hdr_sz, virtio_if_type_t type)
 {
   if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM)
     {
       u16 ethertype = 0, l2hdr_sz = 0;

       if (type == VIRTIO_IF_TYPE_TUN)
 	{
 	  switch (b0->data[0] & 0xf0)
 	    {
 	    case 0x40:
 	      ethertype = ETHERNET_TYPE_IP4;
 	      break;
 	    case 0x60:
 	      ethertype = ETHERNET_TYPE_IP6;
 	      break;
 	    }
 	}
       else
 	{
 	  ethernet_header_t *eh =
 	    (ethernet_header_t *) vlib_buffer_get_current (b0);
 	  ethertype = clib_net_to_host_u16 (eh->type);
 	  l2hdr_sz = sizeof (ethernet_header_t);

 	  if (ethernet_frame_is_tagged (ethertype))
 	    {
 	      ethernet_vlan_header_t *vlan =
 		(ethernet_vlan_header_t *) (eh + 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 (b0)->l2_hdr_offset = 0;
       vnet_buffer (b0)->l3_hdr_offset = l2hdr_sz;

       if (PREDICT_TRUE (ethertype == ETHERNET_TYPE_IP4))
 	{
 	  ip4_header_t *ip4 =
 	    (ip4_header_t *) (vlib_buffer_get_current (b0) + l2hdr_sz);
 	  vnet_buffer (b0)->l4_hdr_offset = l2hdr_sz + ip4_header_bytes (ip4);
 	  *l4_proto = ip4->protocol;
 	  b0->flags |=
 	    (VNET_BUFFER_F_IS_IP4 | VNET_BUFFER_F_OFFLOAD_IP_CKSUM);
 	  b0->flags |=
 	    (VNET_BUFFER_F_L2_HDR_OFFSET_VALID
 	     | VNET_BUFFER_F_L3_HDR_OFFSET_VALID |
 	     VNET_BUFFER_F_L4_HDR_OFFSET_VALID);
 	}
       else if (PREDICT_TRUE (ethertype == ETHERNET_TYPE_IP6))
 	{
 	  ip6_header_t *ip6 =
 	    (ip6_header_t *) (vlib_buffer_get_current (b0) + l2hdr_sz);
 	  vnet_buffer (b0)->l4_hdr_offset = l2hdr_sz + sizeof (ip6_header_t);
 	  /* FIXME IPv6 EH traversal */
 	  *l4_proto = ip6->protocol;
 	  b0->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);
 	}
       if (*l4_proto == IP_PROTOCOL_TCP)
 	{
 	  b0->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
 	  tcp_header_t *tcp = (tcp_header_t *) (vlib_buffer_get_current (b0) +
 						vnet_buffer
 						(b0)->l4_hdr_offset);
 	  *l4_hdr_sz = tcp_header_bytes (tcp);
 	}
       else if (*l4_proto == IP_PROTOCOL_UDP)
 	{
 	  b0->flags |= VNET_BUFFER_F_OFFLOAD_UDP_CKSUM;
 	  udp_header_t *udp = (udp_header_t *) (vlib_buffer_get_current (b0) +
 						vnet_buffer
 						(b0)->l4_hdr_offset);
 	  *l4_hdr_sz = sizeof (*udp);
 	}
     }
 }

 static_always_inline void
 fill_gso_buffer_flags (vlib_buffer_t * b0, virtio_net_hdr_v1_t * hdr,
 		       u8 l4_proto, u8 l4_hdr_sz)
 {
   if (hdr->gso_type == VIRTIO_NET_HDR_GSO_TCPV4)
     {
       ASSERT (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM);
       vnet_buffer2 (b0)->gso_size = hdr->gso_size;
       vnet_buffer2 (b0)->gso_l4_hdr_sz = l4_hdr_sz;
       b0->flags |= VNET_BUFFER_F_GSO | VNET_BUFFER_F_IS_IP4;
     }
   if (hdr->gso_type == VIRTIO_NET_HDR_GSO_TCPV6)
     {
       ASSERT (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM);
       vnet_buffer2 (b0)->gso_size = hdr->gso_size;
       vnet_buffer2 (b0)->gso_l4_hdr_sz = l4_hdr_sz;
       b0->flags |= VNET_BUFFER_F_GSO | VNET_BUFFER_F_IS_IP6;
     }
 }

 static_always_inline uword
 virtio_device_input_gso_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
 				vlib_frame_t * frame, virtio_if_t * vif,
 				u16 qid, virtio_if_type_t type,
 				int gso_enabled, int checksum_offload_enabled)
 {
   vnet_main_t *vnm = vnet_get_main ();
   u32 thread_index = vm->thread_index;
   uword n_trace = vlib_get_trace_count (vm, node);
   virtio_vring_t *vring = vec_elt_at_index (vif->rxq_vrings, qid);
   u16 txq_id = thread_index % vif->num_txqs;
   virtio_vring_t *txq_vring = vec_elt_at_index (vif->txq_vrings, txq_id);
   u32 next_index = VNET_DEVICE_INPUT_NEXT_ETHERNET_INPUT;
   const int hdr_sz = vif->virtio_net_hdr_sz;
   u32 *to_next = 0;
   u32 n_rx_packets = 0;
   u32 n_rx_bytes = 0;
   u16 mask = vring->size - 1;
   u16 last = vring->last_used_idx;
   u16 n_left = vring->used->idx - last;

   if (clib_spinlock_trylock_if_init (&txq_vring->lockp))
     {
       if (vif->packet_coalesce)
 	vnet_gro_flow_table_schedule_node_on_dispatcher (vm,
 							 txq_vring->flow_table);
       else if (vif->packet_buffering)
 	virtio_vring_buffering_schedule_node_on_dispatcher (vm,
 							    txq_vring->buffering);
       clib_spinlock_unlock_if_init (&txq_vring->lockp);
     }

   if ((vring->used->flags & VRING_USED_F_NO_NOTIFY) == 0 &&
       vring->last_kick_avail_idx != vring->avail->idx)
     virtio_kick (vm, vring, vif);

   if (n_left == 0)
     goto refill;

   if (type == VIRTIO_IF_TYPE_TUN)
     next_index = VNET_DEVICE_INPUT_NEXT_IP4_INPUT;

   while (n_left)
     {
       u32 n_left_to_next;
       u32 next0 = next_index;

       vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);

       while (n_left && n_left_to_next)
 	{
 	  u8 l4_proto = 0, l4_hdr_sz = 0;
 	  u16 num_buffers = 1;
 	  vring_used_elem_t *e = &vring->used->ring[last & mask];
 	  virtio_net_hdr_v1_t *hdr;
 	  u16 slot = e->id;
 	  u16 len = e->len - hdr_sz;
 	  u32 bi0 = vring->buffers[slot];
 	  vlib_buffer_t *b0 = vlib_get_buffer (vm, bi0);
 	  hdr = vlib_buffer_get_current (b0);
 	  if (hdr_sz == sizeof (virtio_net_hdr_v1_t))
 	    num_buffers = hdr->num_buffers;

 	  b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
 	  b0->current_data = 0;
 	  b0->current_length = len;

 	  if (checksum_offload_enabled)
 	    virtio_needs_csum (b0, hdr, &l4_proto, &l4_hdr_sz, type);

 	  if (gso_enabled)
 	    fill_gso_buffer_flags (b0, hdr, l4_proto, l4_hdr_sz);

 	  vnet_buffer (b0)->sw_if_index[VLIB_RX] = vif->sw_if_index;
 	  vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;

 	  /* if multisegment packet */
 	  if (PREDICT_FALSE (num_buffers > 1))
 	    {
 	      vlib_buffer_t *pb, *cb;
 	      pb = b0;
 	      b0->total_length_not_including_first_buffer = 0;
 	      while (num_buffers > 1)
 		{
 		  last++;
 		  e = &vring->used->ring[last & mask];
 		  u32 cbi = vring->buffers[e->id];
 		  cb = vlib_get_buffer (vm, cbi);

 		  /* current buffer */
 		  cb->current_length = e->len;

 		  /* previous buffer */
 		  pb->next_buffer = cbi;
 		  pb->flags |= VLIB_BUFFER_NEXT_PRESENT;

 		  /* first buffer */
 		  b0->total_length_not_including_first_buffer += e->len;

 		  pb = cb;
 		  vring->desc_in_use--;
 		  num_buffers--;
 		  n_left--;
 		}
 	      len += b0->total_length_not_including_first_buffer;
 	    }

 	  if (type == VIRTIO_IF_TYPE_TUN)
 	    {
 	      switch (b0->data[0] & 0xf0)
 		{
 		case 0x40:
 		  next0 = VNET_DEVICE_INPUT_NEXT_IP4_INPUT;
 		  break;
 		case 0x60:
 		  next0 = VNET_DEVICE_INPUT_NEXT_IP6_INPUT;
 		  break;
 		default:
 		  next0 = VNET_DEVICE_INPUT_NEXT_DROP;
 		  break;
 		}
 	    }

 	  if (PREDICT_FALSE (vif->per_interface_next_index != ~0))
 	    next0 = vif->per_interface_next_index;

 	  if (type != VIRTIO_IF_TYPE_TUN)
 	    {
 	      /* only for l2, redirect if feature path enabled */
 	      vnet_feature_start_device_input_x1 (vif->sw_if_index, &next0,
 						  b0);
 	    }

 	  /* trace */
 	  VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b0);

 	  if (PREDICT_FALSE (n_trace > 0))
 	    {
 	      virtio_input_trace_t *tr;
 	      vlib_trace_buffer (vm, node, next0, b0,
 				 /* follow_chain */ 1);
 	      vlib_set_trace_count (vm, node, --n_trace);
 	      tr = vlib_add_trace (vm, node, b0, sizeof (*tr));
 	      tr->next_index = next0;
 	      tr->hw_if_index = vif->hw_if_index;
 	      tr->len = len;
 	      clib_memcpy_fast (&tr->hdr, hdr, hdr_sz);
 	    }

 	  /* enqueue buffer */
 	  to_next[0] = bi0;
 	  vring->desc_in_use--;
 	  to_next += 1;
 	  n_left_to_next--;
 	  n_left--;
 	  last++;

 	  /* enqueue */
 	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
 					   n_left_to_next, bi0, next0);

 	  /* next packet */
 	  n_rx_packets++;
 	  n_rx_bytes += len;
 	}
       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
     }
   vring->last_used_idx = last;

   vlib_increment_combined_counter (vnm->interface_main.combined_sw_if_counters
 				   + VNET_INTERFACE_COUNTER_RX, thread_index,
 				   vif->sw_if_index, n_rx_packets,
 				   n_rx_bytes);

 refill:
   virtio_refill_vring (vm, vif, type, vring, hdr_sz, node->node_index);

   return n_rx_packets;
 }

 static_always_inline uword
 virtio_device_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
 			    vlib_frame_t * frame, virtio_if_t * vif, u16 qid,
 			    virtio_if_type_t type)
 {

   if (vif->gso_enabled)
     return virtio_device_input_gso_inline (vm, node, frame, vif,
 					   qid, type, 1, 1);
   else if (vif->csum_offload_enabled)
     return virtio_device_input_gso_inline (vm, node, frame, vif,
 					   qid, type, 0, 1);
   else
     return virtio_device_input_gso_inline (vm, node, frame, vif,
 					   qid, type, 0, 0);
   return 0;
 }

 VLIB_NODE_FN (virtio_input_node) (vlib_main_t * vm,
 				  vlib_node_runtime_t * node,
 				  vlib_frame_t * frame)
 {
   u32 n_rx = 0;
   virtio_main_t *nm = &virtio_main;
   vnet_device_input_runtime_t *rt = (void *) node->runtime_data;
   vnet_device_and_queue_t *dq;

   foreach_device_and_queue (dq, rt->devices_and_queues)
   {
     virtio_if_t *vif;
     vif = vec_elt_at_index (nm->interfaces, dq->dev_instance);
     if (vif->flags & VIRTIO_IF_FLAG_ADMIN_UP)
       {
 	if (vif->type == VIRTIO_IF_TYPE_TAP)
 	  n_rx += virtio_device_input_inline (vm, node, frame, vif,
 					      dq->queue_id,
 					      VIRTIO_IF_TYPE_TAP);
 	else if (vif->type == VIRTIO_IF_TYPE_PCI)
 	  n_rx += virtio_device_input_inline (vm, node, frame, vif,
 					      dq->queue_id,
 					      VIRTIO_IF_TYPE_PCI);
 	else if (vif->type == VIRTIO_IF_TYPE_TUN)
 	  n_rx += virtio_device_input_inline (vm, node, frame, vif,
 					      dq->queue_id,
 					      VIRTIO_IF_TYPE_TUN);
       }
   }

   return n_rx;
 }

 /* *INDENT-OFF* */
 VLIB_REGISTER_NODE (virtio_input_node) = {
   .name = "virtio-input",
   .sibling_of = "device-input",
   .format_trace = format_virtio_input_trace,
   .flags = VLIB_NODE_FLAG_TRACE_SUPPORTED,
   .type = VLIB_NODE_TYPE_INPUT,
   .state = VLIB_NODE_STATE_INTERRUPT,
   .n_errors = VIRTIO_INPUT_N_ERROR,
   .error_strings = virtio_input_error_strings,
 };
 /* *INDENT-ON* */

 /*
  * fd.io coding-style-patch-verification: ON
  *
  * Local Variables:
  * eval: (c-set-style "gnu")
  * End:
  */
	/*
	*------------------------------------------------------------------
	* Copyright (c) 2016 Cisco and/or its affiliates.
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at:
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*------------------------------------------------------------------
	*/

	#include <sys/types.h>
	#include <sys/stat.h>
	#include <fcntl.h>
	#include <net/if.h>
	#include <linux/if_tun.h>
	#include <sys/ioctl.h>
	#include <sys/eventfd.h>

	#include <vlib/vlib.h>
	#include <vlib/unix/unix.h>
	#include <vnet/ethernet/ethernet.h>
	#include <vnet/devices/devices.h>
	#include <vnet/feature/feature.h>
	#include <vnet/gso/gro_func.h>
	#include <vnet/ip/ip4_packet.h>
	#include <vnet/ip/ip6_packet.h>
	#include <vnet/udp/udp_packet.h>
	#include <vnet/devices/virtio/virtio.h>


	#define foreach_virtio_input_error \
	_(BUFFER_ALLOC, "buffer alloc error") \
	_(UNKNOWN, "unknown")

	typedef enum
	{
	#define _(f,s) VIRTIO_INPUT_ERROR_##f,
	foreach_virtio_input_error
	#undef _
	VIRTIO_INPUT_N_ERROR,
	} virtio_input_error_t;

	static char *virtio_input_error_strings[] = {
	#define _(n,s) s,
	foreach_virtio_input_error
	#undef _
	};

	typedef struct
	{
	u32 next_index;
	u32 hw_if_index;
	u16 ring;
	u16 len;
	virtio_net_hdr_v1_t hdr;
	} virtio_input_trace_t;

	static u8 *
	format_virtio_input_trace (u8 * s, va_list * args)
	{
	CLIB_UNUSED (vlib_main_t * vm) = va_arg (args, vlib_main_t );
	CLIB_UNUSED (vlib_node_t * node) = va_arg (args, vlib_node_t );
	virtio_input_trace_t t = va_arg (args, virtio_input_trace_t *);
	u32 indent = format_get_indent (s);

	s = format (s, "virtio: hw_if_index %d next-index %d vring %u len %u",
	t->hw_if_index, t->next_index, t->ring, t->len);
	s = format (s, "\n%Uhdr: flags 0x%02x gso_type 0x%02x hdr_len %u "
	"gso_size %u csum_start %u csum_offset %u num_buffers %u",
	format_white_space, indent + 2,
	t->hdr.flags, t->hdr.gso_type, t->hdr.hdr_len, t->hdr.gso_size,
	t->hdr.csum_start, t->hdr.csum_offset, t->hdr.num_buffers);
	return s;
	}

	static_always_inline void
	virtio_refill_vring (vlib_main_t * vm, virtio_if_t * vif,
	virtio_if_type_t type, virtio_vring_t * vring,
	const int hdr_sz, u32 node_index)
	{
	u16 used, next, avail, n_slots, n_refill;
	u16 sz = vring->size;
	u16 mask = sz - 1;

	more:
	used = vring->desc_in_use;

	if (sz - used < sz / 8)
	return;

	/* deliver free buffers in chunks of 64 */
	n_refill = clib_min (sz - used, 64);

	next = vring->desc_next;
	avail = vring->avail->idx;
	n_slots =
	vlib_buffer_alloc_to_ring_from_pool (vm, vring->buffers, next,
	vring->size, n_refill,
	vring->buffer_pool_index);

	if (PREDICT_FALSE (n_slots != n_refill))
	{
	vlib_error_count (vm, node_index,
	VIRTIO_INPUT_ERROR_BUFFER_ALLOC, n_refill - n_slots);
	if (n_slots == 0)
	return;
	}

	while (n_slots)
	{
	vring_desc_t *d = &vring->desc[next];;
	vlib_buffer_t *b = vlib_get_buffer (vm, vring->buffers[next]);
	/*
	* current_data may not be initialized with 0 and may contain
	* previous offset. Here we want to make sure, it should be 0
	* initialized.
	*/
	b->current_data = -hdr_sz;
	memset (vlib_buffer_get_current (b), 0, hdr_sz);
	d->addr =
	((type == VIRTIO_IF_TYPE_PCI) ? vlib_buffer_get_current_pa (vm,
	b) :
	pointer_to_uword (vlib_buffer_get_current (b)));
	d->len = vlib_buffer_get_default_data_size (vm) + hdr_sz;
	d->flags = VRING_DESC_F_WRITE;
	vring->avail->ring[avail & mask] = next;
	avail++;
	next = (next + 1) & mask;
	n_slots--;
	used++;
	}
	CLIB_MEMORY_STORE_BARRIER ();
	vring->avail->idx = avail;
	vring->desc_next = next;
	vring->desc_in_use = used;

	if ((vring->used->flags & VRING_USED_F_NO_NOTIFY) == 0)
	{
	virtio_kick (vm, vring, vif);
	}
	goto more;
	}

	static_always_inline void
	virtio_needs_csum (vlib_buffer_t * b0, virtio_net_hdr_v1_t * hdr,
	u8 * l4_proto, u8 * l4_hdr_sz, virtio_if_type_t type)
	{
	if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM)
	{
	u16 ethertype = 0, l2hdr_sz = 0;

	if (type == VIRTIO_IF_TYPE_TUN)
	{
	switch (b0->data[0] & 0xf0)
	{
	case 0x40:
	ethertype = ETHERNET_TYPE_IP4;
	break;
	case 0x60:
	ethertype = ETHERNET_TYPE_IP6;
	break;
	}
	}
	else
	{
	ethernet_header_t *eh =
	(ethernet_header_t *) vlib_buffer_get_current (b0);
	ethertype = clib_net_to_host_u16 (eh->type);
	l2hdr_sz = sizeof (ethernet_header_t);

	if (ethernet_frame_is_tagged (ethertype))
	{
	ethernet_vlan_header_t *vlan =
	(ethernet_vlan_header_t *) (eh + 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 (b0)->l2_hdr_offset = 0;
	vnet_buffer (b0)->l3_hdr_offset = l2hdr_sz;

	if (PREDICT_TRUE (ethertype == ETHERNET_TYPE_IP4))
	{
	ip4_header_t *ip4 =
	(ip4_header_t *) (vlib_buffer_get_current (b0) + l2hdr_sz);
	vnet_buffer (b0)->l4_hdr_offset = l2hdr_sz + ip4_header_bytes (ip4);
	*l4_proto = ip4->protocol;
	b0->flags \|=
	(VNET_BUFFER_F_IS_IP4 \| VNET_BUFFER_F_OFFLOAD_IP_CKSUM);
	b0->flags \|=
	(VNET_BUFFER_F_L2_HDR_OFFSET_VALID
	\| VNET_BUFFER_F_L3_HDR_OFFSET_VALID \|
	VNET_BUFFER_F_L4_HDR_OFFSET_VALID);
	}
	else if (PREDICT_TRUE (ethertype == ETHERNET_TYPE_IP6))
	{
	ip6_header_t *ip6 =
	(ip6_header_t *) (vlib_buffer_get_current (b0) + l2hdr_sz);
	vnet_buffer (b0)->l4_hdr_offset = l2hdr_sz + sizeof (ip6_header_t);
	/* FIXME IPv6 EH traversal */
	*l4_proto = ip6->protocol;
	b0->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);
	}
	if (*l4_proto == IP_PROTOCOL_TCP)
	{
	b0->flags \|= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
	tcp_header_t tcp = (tcp_header_t ) (vlib_buffer_get_current (b0) +
	vnet_buffer
	(b0)->l4_hdr_offset);
	*l4_hdr_sz = tcp_header_bytes (tcp);
	}
	else if (*l4_proto == IP_PROTOCOL_UDP)
	{
	b0->flags \|= VNET_BUFFER_F_OFFLOAD_UDP_CKSUM;
	udp_header_t udp = (udp_header_t ) (vlib_buffer_get_current (b0) +
	vnet_buffer
	(b0)->l4_hdr_offset);
	l4_hdr_sz = sizeof (udp);
	}
	}
	}

	static_always_inline void
	fill_gso_buffer_flags (vlib_buffer_t * b0, virtio_net_hdr_v1_t * hdr,
	u8 l4_proto, u8 l4_hdr_sz)
	{
	if (hdr->gso_type == VIRTIO_NET_HDR_GSO_TCPV4)
	{
	ASSERT (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM);
	vnet_buffer2 (b0)->gso_size = hdr->gso_size;
	vnet_buffer2 (b0)->gso_l4_hdr_sz = l4_hdr_sz;
	b0->flags \|= VNET_BUFFER_F_GSO \| VNET_BUFFER_F_IS_IP4;
	}
	if (hdr->gso_type == VIRTIO_NET_HDR_GSO_TCPV6)
	{
	ASSERT (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM);
	vnet_buffer2 (b0)->gso_size = hdr->gso_size;
	vnet_buffer2 (b0)->gso_l4_hdr_sz = l4_hdr_sz;
	b0->flags \|= VNET_BUFFER_F_GSO \| VNET_BUFFER_F_IS_IP6;
	}
	}

	static_always_inline uword
	virtio_device_input_gso_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
	vlib_frame_t * frame, virtio_if_t * vif,
	u16 qid, virtio_if_type_t type,
	int gso_enabled, int checksum_offload_enabled)
	{
	vnet_main_t *vnm = vnet_get_main ();
	u32 thread_index = vm->thread_index;
	uword n_trace = vlib_get_trace_count (vm, node);
	virtio_vring_t *vring = vec_elt_at_index (vif->rxq_vrings, qid);
	u16 txq_id = thread_index % vif->num_txqs;
	virtio_vring_t *txq_vring = vec_elt_at_index (vif->txq_vrings, txq_id);
	u32 next_index = VNET_DEVICE_INPUT_NEXT_ETHERNET_INPUT;
	const int hdr_sz = vif->virtio_net_hdr_sz;
	u32 *to_next = 0;
	u32 n_rx_packets = 0;
	u32 n_rx_bytes = 0;
	u16 mask = vring->size - 1;
	u16 last = vring->last_used_idx;
	u16 n_left = vring->used->idx - last;

	if (clib_spinlock_trylock_if_init (&txq_vring->lockp))
	{
	if (vif->packet_coalesce)
	vnet_gro_flow_table_schedule_node_on_dispatcher (vm,
	txq_vring->flow_table);
	else if (vif->packet_buffering)
	virtio_vring_buffering_schedule_node_on_dispatcher (vm,
	txq_vring->buffering);
	clib_spinlock_unlock_if_init (&txq_vring->lockp);
	}

	if ((vring->used->flags & VRING_USED_F_NO_NOTIFY) == 0 &&
	vring->last_kick_avail_idx != vring->avail->idx)
	virtio_kick (vm, vring, vif);

	if (n_left == 0)
	goto refill;

	if (type == VIRTIO_IF_TYPE_TUN)
	next_index = VNET_DEVICE_INPUT_NEXT_IP4_INPUT;

	while (n_left)
	{
	u32 n_left_to_next;
	u32 next0 = next_index;

	vlib_get_next_frame (vm, node, next_index, to_next, n_left_to_next);

	while (n_left && n_left_to_next)
	{
	u8 l4_proto = 0, l4_hdr_sz = 0;
	u16 num_buffers = 1;
	vring_used_elem_t *e = &vring->used->ring[last & mask];
	virtio_net_hdr_v1_t *hdr;
	u16 slot = e->id;
	u16 len = e->len - hdr_sz;
	u32 bi0 = vring->buffers[slot];
	vlib_buffer_t *b0 = vlib_get_buffer (vm, bi0);
	hdr = vlib_buffer_get_current (b0);
	if (hdr_sz == sizeof (virtio_net_hdr_v1_t))
	num_buffers = hdr->num_buffers;

	b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
	b0->current_data = 0;
	b0->current_length = len;

	if (checksum_offload_enabled)
	virtio_needs_csum (b0, hdr, &l4_proto, &l4_hdr_sz, type);

	if (gso_enabled)
	fill_gso_buffer_flags (b0, hdr, l4_proto, l4_hdr_sz);

	vnet_buffer (b0)->sw_if_index[VLIB_RX] = vif->sw_if_index;
	vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;

	/* if multisegment packet */
	if (PREDICT_FALSE (num_buffers > 1))
	{
	vlib_buffer_t pb, cb;
	pb = b0;
	b0->total_length_not_including_first_buffer = 0;
	while (num_buffers > 1)
	{
	last++;
	e = &vring->used->ring[last & mask];
	u32 cbi = vring->buffers[e->id];
	cb = vlib_get_buffer (vm, cbi);

	/* current buffer */
	cb->current_length = e->len;

	/* previous buffer */
	pb->next_buffer = cbi;
	pb->flags \|= VLIB_BUFFER_NEXT_PRESENT;

	/* first buffer */
	b0->total_length_not_including_first_buffer += e->len;

	pb = cb;
	vring->desc_in_use--;
	num_buffers--;
	n_left--;
	}
	len += b0->total_length_not_including_first_buffer;
	}

	if (type == VIRTIO_IF_TYPE_TUN)
	{
	switch (b0->data[0] & 0xf0)
	{
	case 0x40:
	next0 = VNET_DEVICE_INPUT_NEXT_IP4_INPUT;
	break;
	case 0x60:
	next0 = VNET_DEVICE_INPUT_NEXT_IP6_INPUT;
	break;
	default:
	next0 = VNET_DEVICE_INPUT_NEXT_DROP;
	break;
	}
	}

	if (PREDICT_FALSE (vif->per_interface_next_index != ~0))
	next0 = vif->per_interface_next_index;

	if (type != VIRTIO_IF_TYPE_TUN)
	{
	/* only for l2, redirect if feature path enabled */
	vnet_feature_start_device_input_x1 (vif->sw_if_index, &next0,
	b0);
	}

	/* trace */
	VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b0);

	if (PREDICT_FALSE (n_trace > 0))
	{
	virtio_input_trace_t *tr;
	vlib_trace_buffer (vm, node, next0, b0,
	/* follow_chain */ 1);
	vlib_set_trace_count (vm, node, --n_trace);
	tr = vlib_add_trace (vm, node, b0, sizeof (*tr));
	tr->next_index = next0;
	tr->hw_if_index = vif->hw_if_index;
	tr->len = len;
	clib_memcpy_fast (&tr->hdr, hdr, hdr_sz);
	}

	/* enqueue buffer */
	to_next[0] = bi0;
	vring->desc_in_use--;
	to_next += 1;
	n_left_to_next--;
	n_left--;
	last++;

	/* enqueue */
	vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
	n_left_to_next, bi0, next0);

	/* next packet */
	n_rx_packets++;
	n_rx_bytes += len;
	}
	vlib_put_next_frame (vm, node, next_index, n_left_to_next);
	}
	vring->last_used_idx = last;

	vlib_increment_combined_counter (vnm->interface_main.combined_sw_if_counters
	+ VNET_INTERFACE_COUNTER_RX, thread_index,
	vif->sw_if_index, n_rx_packets,
	n_rx_bytes);

	refill:
	virtio_refill_vring (vm, vif, type, vring, hdr_sz, node->node_index);

	return n_rx_packets;
	}

	static_always_inline uword
	virtio_device_input_inline (vlib_main_t * vm, vlib_node_runtime_t * node,
	vlib_frame_t * frame, virtio_if_t * vif, u16 qid,
	virtio_if_type_t type)
	{

	if (vif->gso_enabled)
	return virtio_device_input_gso_inline (vm, node, frame, vif,
	qid, type, 1, 1);
	else if (vif->csum_offload_enabled)
	return virtio_device_input_gso_inline (vm, node, frame, vif,
	qid, type, 0, 1);
	else
	return virtio_device_input_gso_inline (vm, node, frame, vif,
	qid, type, 0, 0);
	return 0;
	}

	VLIB_NODE_FN (virtio_input_node) (vlib_main_t * vm,
	vlib_node_runtime_t * node,
	vlib_frame_t * frame)
	{
	u32 n_rx = 0;
	virtio_main_t *nm = &virtio_main;
	vnet_device_input_runtime_t rt = (void ) node->runtime_data;
	vnet_device_and_queue_t *dq;

	foreach_device_and_queue (dq, rt->devices_and_queues)
	{
	virtio_if_t *vif;
	vif = vec_elt_at_index (nm->interfaces, dq->dev_instance);
	if (vif->flags & VIRTIO_IF_FLAG_ADMIN_UP)
	{
	if (vif->type == VIRTIO_IF_TYPE_TAP)
	n_rx += virtio_device_input_inline (vm, node, frame, vif,
	dq->queue_id,
	VIRTIO_IF_TYPE_TAP);
	else if (vif->type == VIRTIO_IF_TYPE_PCI)
	n_rx += virtio_device_input_inline (vm, node, frame, vif,
	dq->queue_id,
	VIRTIO_IF_TYPE_PCI);
	else if (vif->type == VIRTIO_IF_TYPE_TUN)
	n_rx += virtio_device_input_inline (vm, node, frame, vif,
	dq->queue_id,
	VIRTIO_IF_TYPE_TUN);
	}
	}

	return n_rx;
	}

	/* INDENT-OFF */
	VLIB_REGISTER_NODE (virtio_input_node) = {
	.name = "virtio-input",
	.sibling_of = "device-input",
	.format_trace = format_virtio_input_trace,
	.flags = VLIB_NODE_FLAG_TRACE_SUPPORTED,
	.type = VLIB_NODE_TYPE_INPUT,
	.state = VLIB_NODE_STATE_INTERRUPT,
	.n_errors = VIRTIO_INPUT_N_ERROR,
	.error_strings = virtio_input_error_strings,
	};
	/* INDENT-ON */

	/*
	* fd.io coding-style-patch-verification: ON
	*
	* Local Variables:
	* eval: (c-set-style "gnu")
	* End:
	*/