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

 /*
  *------------------------------------------------------------------
  * af_packet.c - linux kernel packet interface
  *
  * 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 <linux/if_packet.h>

 #include <vlib/vlib.h>
 #include <vlib/unix/unix.h>
 #include <vnet/ip/ip.h>
 #include <vnet/ethernet/ethernet.h>
 #include <vnet/devices/devices.h>
 #include <vnet/feature/feature.h>
 #include <vnet/ethernet/packet.h>

 #include <vnet/devices/af_packet/af_packet.h>

 #define foreach_af_packet_input_error \
   _(PARTIAL_PKT, "partial packet")

 typedef enum
 {
 #define _(f,s) AF_PACKET_INPUT_ERROR_##f,
   foreach_af_packet_input_error
 #undef _
     AF_PACKET_INPUT_N_ERROR,
 } af_packet_input_error_t;

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

 typedef struct
 {
   u32 next_index;
   u32 hw_if_index;
   int block;
   struct tpacket2_hdr tph;
 } af_packet_input_trace_t;

 static u8 *
 format_af_packet_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 *);
   af_packet_input_trace_t *t = va_arg (*args, af_packet_input_trace_t *);
   u32 indent = format_get_indent (s);

   s = format (s, "af_packet: hw_if_index %d next-index %d",
 	      t->hw_if_index, t->next_index);

   s =
     format (s,
 	    "\n%Utpacket2_hdr:\n%Ustatus 0x%x len %u snaplen %u mac %u net %u"
 	    "\n%Usec 0x%x nsec 0x%x vlan %U"
 #ifdef TP_STATUS_VLAN_TPID_VALID
 	    " vlan_tpid %u"
 #endif
 	    ,
 	    format_white_space, indent + 2,
 	    format_white_space, indent + 4,
 	    t->tph.tp_status,
 	    t->tph.tp_len,
 	    t->tph.tp_snaplen,
 	    t->tph.tp_mac,
 	    t->tph.tp_net,
 	    format_white_space, indent + 4,
 	    t->tph.tp_sec,
 	    t->tph.tp_nsec, format_ethernet_vlan_tci, t->tph.tp_vlan_tci
 #ifdef TP_STATUS_VLAN_TPID_VALID
 	    , t->tph.tp_vlan_tpid
 #endif
     );
   return s;
 }

 always_inline void
 buffer_add_to_chain (vlib_main_t * vm, u32 bi, u32 first_bi, u32 prev_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;

   /* update previous buffer */
   prev_b->next_buffer = bi;
   prev_b->flags |= VLIB_BUFFER_NEXT_PRESENT;

   /* update current buffer */
   b->next_buffer = 0;
 }

 static_always_inline void
 mark_tcp_udp_cksum_calc (vlib_buffer_t * b)
 {
   ethernet_header_t *eth = vlib_buffer_get_current (b);
   if (clib_net_to_host_u16 (eth->type) == ETHERNET_TYPE_IP4)
     {
       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)
 	{
 	  b->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
 	  ((tcp_header_t
 	    *) (vlib_buffer_get_current (b) +
 		sizeof (ethernet_header_t) +
 		ip4_header_bytes (ip4)))->checksum = 0;
 	}
       else if (ip4->protocol == IP_PROTOCOL_UDP)
 	{
 	  b->flags |= VNET_BUFFER_F_OFFLOAD_UDP_CKSUM;
 	  ((udp_header_t
 	    *) (vlib_buffer_get_current (b) +
 		sizeof (ethernet_header_t) +
 		ip4_header_bytes (ip4)))->checksum = 0;
 	}
       vnet_buffer (b)->l3_hdr_offset = sizeof (ethernet_header_t);
       vnet_buffer (b)->l4_hdr_offset =
 	sizeof (ethernet_header_t) + ip4_header_bytes (ip4);
     }
   else if (clib_net_to_host_u16 (eth->type) == ETHERNET_TYPE_IP6)
     {
       ip6_header_t *ip6 =
 	(vlib_buffer_get_current (b) + sizeof (ethernet_header_t));
       b->flags |= VNET_BUFFER_F_IS_IP6;
       u16 ip6_hdr_len = sizeof (ip6_header_t);
       if (ip6_ext_hdr (ip6->protocol))
 	{
 	  ip6_ext_header_t *p = (void *) (ip6 + 1);
 	  ip6_hdr_len += ip6_ext_header_len (p);
 	  while (ip6_ext_hdr (p->next_hdr))
 	    {
 	      ip6_hdr_len += ip6_ext_header_len (p);
 	      p = ip6_ext_next_header (p);
 	    }
 	}
       if (ip6->protocol == IP_PROTOCOL_TCP)
 	{
 	  b->flags |= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
 	  ((tcp_header_t
 	    *) (vlib_buffer_get_current (b) +
 		sizeof (ethernet_header_t) + ip6_hdr_len))->checksum = 0;
 	}
       else if (ip6->protocol == IP_PROTOCOL_UDP)
 	{
 	  b->flags |= VNET_BUFFER_F_OFFLOAD_UDP_CKSUM;
 	  ((udp_header_t
 	    *) (vlib_buffer_get_current (b) +
 		sizeof (ethernet_header_t) + ip6_hdr_len))->checksum = 0;
 	}
       vnet_buffer (b)->l3_hdr_offset = sizeof (ethernet_header_t);
       vnet_buffer (b)->l4_hdr_offset =
 	sizeof (ethernet_header_t) + ip6_hdr_len;
     }
 }

 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_main_t *apm = &af_packet_main;
   struct tpacket2_hdr *tph;
   u32 next_index = VNET_DEVICE_INPUT_NEXT_ETHERNET_INPUT;
   u32 block = 0;
   u32 rx_frame;
   u32 n_free_bufs;
   u32 n_rx_packets = 0;
   u32 n_rx_bytes = 0;
   u32 *to_next = 0;
   u32 block_size = apif->rx_req->tp_block_size;
   u32 frame_size = apif->rx_req->tp_frame_size;
   u32 frame_num = apif->rx_req->tp_frame_nr;
   u8 *block_start = apif->rx_ring + block * block_size;
   uword n_trace = vlib_get_trace_count (vm, node);
   u32 thread_index = vlib_get_thread_index ();
   u32 n_buffer_bytes = vlib_buffer_free_list_buffer_size (vm,
 							  VLIB_BUFFER_DEFAULT_FREE_LIST_INDEX);
   u32 min_bufs = apif->rx_req->tp_frame_size / n_buffer_bytes;

   if (apif->per_interface_next_index != ~0)
     next_index = apif->per_interface_next_index;

   n_free_bufs = vec_len (apm->rx_buffers[thread_index]);
   if (PREDICT_FALSE (n_free_bufs < VLIB_FRAME_SIZE))
     {
       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;
     }

   rx_frame = apif->next_rx_frame;
   tph = (struct tpacket2_hdr *) (block_start + rx_frame * frame_size);
   while ((tph->tp_status & TP_STATUS_USER) && (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 ((tph->tp_status & TP_STATUS_USER) && (n_free_bufs > min_bufs) &&
 	     n_left_to_next)
 	{
 	  u32 data_len = tph->tp_snaplen;
 	  u32 offset = 0;
 	  u32 bi0 = 0, first_bi0 = 0, prev_bi0;

 	  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--;

 	      /* copy data */
 	      u32 bytes_to_copy =
 		data_len > n_buffer_bytes ? n_buffer_bytes : data_len;
 	      u32 vlan_len = 0;
 	      u32 bytes_copied = 0;
 	      b0->current_data = 0;
 	      /* Kernel removes VLAN headers, so reconstruct VLAN */
 	      if (PREDICT_FALSE (tph->tp_status & TP_STATUS_VLAN_VALID))
 		{
 		  if (PREDICT_TRUE (offset == 0))
 		    {
 		      clib_memcpy (vlib_buffer_get_current (b0),
 				   (u8 *) tph + tph->tp_mac,
 				   sizeof (ethernet_header_t));
 		      ethernet_header_t *eth = vlib_buffer_get_current (b0);
 		      ethernet_vlan_header_t *vlan =
 			(ethernet_vlan_header_t *) (eth + 1);
 		      vlan->priority_cfi_and_id =
 			clib_host_to_net_u16 (tph->tp_vlan_tci);
 		      vlan->type = eth->type;
 		      eth->type = clib_host_to_net_u16 (ETHERNET_TYPE_VLAN);
 		      vlan_len = sizeof (ethernet_vlan_header_t);
 		      bytes_copied = sizeof (ethernet_header_t);
 		    }
 		}
 	      clib_memcpy (((u8 *) vlib_buffer_get_current (b0)) +
 			   bytes_copied + vlan_len,
 			   (u8 *) tph + tph->tp_mac + offset + bytes_copied,
 			   (bytes_to_copy - bytes_copied));

 	      /* fill buffer header */
 	      b0->current_length = bytes_to_copy + vlan_len;

 	      if (offset == 0)
 		{
 		  b0->total_length_not_including_first_buffer = 0;
 		  b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
 		  vnet_buffer (b0)->sw_if_index[VLIB_RX] = apif->sw_if_index;
 		  vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
 		  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);
 		}
 	      else
 		buffer_add_to_chain (vm, bi0, first_bi0, prev_bi0);

 	      offset += bytes_to_copy;
 	      data_len -= bytes_to_copy;
 	    }
 	  n_rx_packets++;
 	  n_rx_bytes += tph->tp_snaplen;
 	  to_next[0] = first_bi0;
 	  to_next += 1;
 	  n_left_to_next--;

 	  /* drop partial packets */
 	  if (PREDICT_FALSE (tph->tp_len != tph->tp_snaplen))
 	    {
 	      next0 = VNET_DEVICE_INPUT_NEXT_DROP;
 	      first_b0->error =
 		node->errors[AF_PACKET_INPUT_ERROR_PARTIAL_PKT];
 	    }
 	  else
 	    {
 	      next0 = VNET_DEVICE_INPUT_NEXT_ETHERNET_INPUT;
 	      /* redirect if feature path enabled */
 	      vnet_feature_start_device_input_x1 (apif->sw_if_index, &next0,
 						  first_b0);
 	    }

 	  /* trace */
 	  VLIB_BUFFER_TRACE_TRAJECTORY_INIT (first_b0);
 	  if (PREDICT_FALSE (n_trace > 0))
 	    {
 	      af_packet_input_trace_t *tr;
 	      vlib_trace_buffer (vm, node, next0, first_b0,	/* follow_chain */
 				 0);
 	      vlib_set_trace_count (vm, node, --n_trace);
 	      tr = vlib_add_trace (vm, node, first_b0, sizeof (*tr));
 	      tr->next_index = next0;
 	      tr->hw_if_index = apif->hw_if_index;
 	      clib_memcpy (&tr->tph, tph, sizeof (struct tpacket2_hdr));
 	    }

 	  /* enque and take next packet */
 	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
 					   n_left_to_next, first_bi0, next0);

 	  /* next packet */
 	  tph->tp_status = TP_STATUS_KERNEL;
 	  rx_frame = (rx_frame + 1) % frame_num;
 	  tph = (struct tpacket2_hdr *) (block_start + rx_frame * frame_size);
 	}

       vlib_put_next_frame (vm, node, next_index, n_left_to_next);
     }

   apif->next_rx_frame = rx_frame;

   vlib_increment_combined_counter
     (vnet_get_main ()->interface_main.combined_sw_if_counters
      + VNET_INTERFACE_COUNTER_RX,
      vlib_get_thread_index (), apif->hw_if_index, n_rx_packets, n_rx_bytes);

   vnet_device_increment_rx_packets (thread_index, n_rx_packets);
   return n_rx_packets;
 }

 static uword
 af_packet_input_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
 		    vlib_frame_t * frame)
 {
   u32 n_rx_packets = 0;
   af_packet_main_t *apm = &af_packet_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)
   {
     af_packet_if_t *apif;
     apif = vec_elt_at_index (apm->interfaces, dq->dev_instance);
     if (apif->is_admin_up)
       n_rx_packets += af_packet_device_input_fn (vm, node, frame, apif);
   }

   return n_rx_packets;
 }

 /* *INDENT-OFF* */
 VLIB_REGISTER_NODE (af_packet_input_node) = {
   .function = af_packet_input_fn,
   .name = "af-packet-input",
   .sibling_of = "device-input",
   .format_trace = format_af_packet_input_trace,
   .type = VLIB_NODE_TYPE_INPUT,
   .state = VLIB_NODE_STATE_INTERRUPT,
   .n_errors = AF_PACKET_INPUT_N_ERROR,
   .error_strings = af_packet_input_error_strings,
 };

 VLIB_NODE_FUNCTION_MULTIARCH (af_packet_input_node, af_packet_input_fn)
 /* *INDENT-ON* */


 /*
  * fd.io coding-style-patch-verification: ON
  *
  * Local Variables:
  * eval: (c-set-style "gnu")
  * End:
  */
	/*
	*------------------------------------------------------------------
	* af_packet.c - linux kernel packet interface
	*
	* 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 <linux/if_packet.h>

	#include <vlib/vlib.h>
	#include <vlib/unix/unix.h>
	#include <vnet/ip/ip.h>
	#include <vnet/ethernet/ethernet.h>
	#include <vnet/devices/devices.h>
	#include <vnet/feature/feature.h>
	#include <vnet/ethernet/packet.h>

	#include <vnet/devices/af_packet/af_packet.h>

	#define foreach_af_packet_input_error \
	_(PARTIAL_PKT, "partial packet")

	typedef enum
	{
	#define _(f,s) AF_PACKET_INPUT_ERROR_##f,
	foreach_af_packet_input_error
	#undef _
	AF_PACKET_INPUT_N_ERROR,
	} af_packet_input_error_t;

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

	typedef struct
	{
	u32 next_index;
	u32 hw_if_index;
	int block;
	struct tpacket2_hdr tph;
	} af_packet_input_trace_t;

	static u8 *
	format_af_packet_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 );
	af_packet_input_trace_t t = va_arg (args, af_packet_input_trace_t *);
	u32 indent = format_get_indent (s);

	s = format (s, "af_packet: hw_if_index %d next-index %d",
	t->hw_if_index, t->next_index);

	s =
	format (s,
	"\n%Utpacket2_hdr:\n%Ustatus 0x%x len %u snaplen %u mac %u net %u"
	"\n%Usec 0x%x nsec 0x%x vlan %U"
	#ifdef TP_STATUS_VLAN_TPID_VALID
	" vlan_tpid %u"
	#endif
	,
	format_white_space, indent + 2,
	format_white_space, indent + 4,
	t->tph.tp_status,
	t->tph.tp_len,
	t->tph.tp_snaplen,
	t->tph.tp_mac,
	t->tph.tp_net,
	format_white_space, indent + 4,
	t->tph.tp_sec,
	t->tph.tp_nsec, format_ethernet_vlan_tci, t->tph.tp_vlan_tci
	#ifdef TP_STATUS_VLAN_TPID_VALID
	, t->tph.tp_vlan_tpid
	#endif
	);
	return s;
	}

	always_inline void
	buffer_add_to_chain (vlib_main_t * vm, u32 bi, u32 first_bi, u32 prev_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;

	/* update previous buffer */
	prev_b->next_buffer = bi;
	prev_b->flags \|= VLIB_BUFFER_NEXT_PRESENT;

	/* update current buffer */
	b->next_buffer = 0;
	}

	static_always_inline void
	mark_tcp_udp_cksum_calc (vlib_buffer_t * b)
	{
	ethernet_header_t *eth = vlib_buffer_get_current (b);
	if (clib_net_to_host_u16 (eth->type) == ETHERNET_TYPE_IP4)
	{
	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)
	{
	b->flags \|= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
	((tcp_header_t
	*) (vlib_buffer_get_current (b) +
	sizeof (ethernet_header_t) +
	ip4_header_bytes (ip4)))->checksum = 0;
	}
	else if (ip4->protocol == IP_PROTOCOL_UDP)
	{
	b->flags \|= VNET_BUFFER_F_OFFLOAD_UDP_CKSUM;
	((udp_header_t
	*) (vlib_buffer_get_current (b) +
	sizeof (ethernet_header_t) +
	ip4_header_bytes (ip4)))->checksum = 0;
	}
	vnet_buffer (b)->l3_hdr_offset = sizeof (ethernet_header_t);
	vnet_buffer (b)->l4_hdr_offset =
	sizeof (ethernet_header_t) + ip4_header_bytes (ip4);
	}
	else if (clib_net_to_host_u16 (eth->type) == ETHERNET_TYPE_IP6)
	{
	ip6_header_t *ip6 =
	(vlib_buffer_get_current (b) + sizeof (ethernet_header_t));
	b->flags \|= VNET_BUFFER_F_IS_IP6;
	u16 ip6_hdr_len = sizeof (ip6_header_t);
	if (ip6_ext_hdr (ip6->protocol))
	{
	ip6_ext_header_t p = (void ) (ip6 + 1);
	ip6_hdr_len += ip6_ext_header_len (p);
	while (ip6_ext_hdr (p->next_hdr))
	{
	ip6_hdr_len += ip6_ext_header_len (p);
	p = ip6_ext_next_header (p);
	}
	}
	if (ip6->protocol == IP_PROTOCOL_TCP)
	{
	b->flags \|= VNET_BUFFER_F_OFFLOAD_TCP_CKSUM;
	((tcp_header_t
	*) (vlib_buffer_get_current (b) +
	sizeof (ethernet_header_t) + ip6_hdr_len))->checksum = 0;
	}
	else if (ip6->protocol == IP_PROTOCOL_UDP)
	{
	b->flags \|= VNET_BUFFER_F_OFFLOAD_UDP_CKSUM;
	((udp_header_t
	*) (vlib_buffer_get_current (b) +
	sizeof (ethernet_header_t) + ip6_hdr_len))->checksum = 0;
	}
	vnet_buffer (b)->l3_hdr_offset = sizeof (ethernet_header_t);
	vnet_buffer (b)->l4_hdr_offset =
	sizeof (ethernet_header_t) + ip6_hdr_len;
	}
	}

	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_main_t *apm = &af_packet_main;
	struct tpacket2_hdr *tph;
	u32 next_index = VNET_DEVICE_INPUT_NEXT_ETHERNET_INPUT;
	u32 block = 0;
	u32 rx_frame;
	u32 n_free_bufs;
	u32 n_rx_packets = 0;
	u32 n_rx_bytes = 0;
	u32 *to_next = 0;
	u32 block_size = apif->rx_req->tp_block_size;
	u32 frame_size = apif->rx_req->tp_frame_size;
	u32 frame_num = apif->rx_req->tp_frame_nr;
	u8 block_start = apif->rx_ring + block block_size;
	uword n_trace = vlib_get_trace_count (vm, node);
	u32 thread_index = vlib_get_thread_index ();
	u32 n_buffer_bytes = vlib_buffer_free_list_buffer_size (vm,
	VLIB_BUFFER_DEFAULT_FREE_LIST_INDEX);
	u32 min_bufs = apif->rx_req->tp_frame_size / n_buffer_bytes;

	if (apif->per_interface_next_index != ~0)
	next_index = apif->per_interface_next_index;

	n_free_bufs = vec_len (apm->rx_buffers[thread_index]);
	if (PREDICT_FALSE (n_free_bufs < VLIB_FRAME_SIZE))
	{
	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;
	}

	rx_frame = apif->next_rx_frame;
	tph = (struct tpacket2_hdr ) (block_start + rx_frame frame_size);
	while ((tph->tp_status & TP_STATUS_USER) && (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 ((tph->tp_status & TP_STATUS_USER) && (n_free_bufs > min_bufs) &&
	n_left_to_next)
	{
	u32 data_len = tph->tp_snaplen;
	u32 offset = 0;
	u32 bi0 = 0, first_bi0 = 0, prev_bi0;

	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--;

	/* copy data */
	u32 bytes_to_copy =
	data_len > n_buffer_bytes ? n_buffer_bytes : data_len;
	u32 vlan_len = 0;
	u32 bytes_copied = 0;
	b0->current_data = 0;
	/* Kernel removes VLAN headers, so reconstruct VLAN */
	if (PREDICT_FALSE (tph->tp_status & TP_STATUS_VLAN_VALID))
	{
	if (PREDICT_TRUE (offset == 0))
	{
	clib_memcpy (vlib_buffer_get_current (b0),
	(u8 *) tph + tph->tp_mac,
	sizeof (ethernet_header_t));
	ethernet_header_t *eth = vlib_buffer_get_current (b0);
	ethernet_vlan_header_t *vlan =
	(ethernet_vlan_header_t *) (eth + 1);
	vlan->priority_cfi_and_id =
	clib_host_to_net_u16 (tph->tp_vlan_tci);
	vlan->type = eth->type;
	eth->type = clib_host_to_net_u16 (ETHERNET_TYPE_VLAN);
	vlan_len = sizeof (ethernet_vlan_header_t);
	bytes_copied = sizeof (ethernet_header_t);
	}
	}
	clib_memcpy (((u8 *) vlib_buffer_get_current (b0)) +
	bytes_copied + vlan_len,
	(u8 *) tph + tph->tp_mac + offset + bytes_copied,
	(bytes_to_copy - bytes_copied));

	/* fill buffer header */
	b0->current_length = bytes_to_copy + vlan_len;

	if (offset == 0)
	{
	b0->total_length_not_including_first_buffer = 0;
	b0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID;
	vnet_buffer (b0)->sw_if_index[VLIB_RX] = apif->sw_if_index;
	vnet_buffer (b0)->sw_if_index[VLIB_TX] = (u32) ~ 0;
	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);
	}
	else
	buffer_add_to_chain (vm, bi0, first_bi0, prev_bi0);

	offset += bytes_to_copy;
	data_len -= bytes_to_copy;
	}
	n_rx_packets++;
	n_rx_bytes += tph->tp_snaplen;
	to_next[0] = first_bi0;
	to_next += 1;
	n_left_to_next--;

	/* drop partial packets */
	if (PREDICT_FALSE (tph->tp_len != tph->tp_snaplen))
	{
	next0 = VNET_DEVICE_INPUT_NEXT_DROP;
	first_b0->error =
	node->errors[AF_PACKET_INPUT_ERROR_PARTIAL_PKT];
	}
	else
	{
	next0 = VNET_DEVICE_INPUT_NEXT_ETHERNET_INPUT;
	/* redirect if feature path enabled */
	vnet_feature_start_device_input_x1 (apif->sw_if_index, &next0,
	first_b0);
	}

	/* trace */
	VLIB_BUFFER_TRACE_TRAJECTORY_INIT (first_b0);
	if (PREDICT_FALSE (n_trace > 0))
	{
	af_packet_input_trace_t *tr;
	vlib_trace_buffer (vm, node, next0, first_b0, /* follow_chain */
	0);
	vlib_set_trace_count (vm, node, --n_trace);
	tr = vlib_add_trace (vm, node, first_b0, sizeof (*tr));
	tr->next_index = next0;
	tr->hw_if_index = apif->hw_if_index;
	clib_memcpy (&tr->tph, tph, sizeof (struct tpacket2_hdr));
	}

	/* enque and take next packet */
	vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
	n_left_to_next, first_bi0, next0);

	/* next packet */
	tph->tp_status = TP_STATUS_KERNEL;
	rx_frame = (rx_frame + 1) % frame_num;
	tph = (struct tpacket2_hdr ) (block_start + rx_frame frame_size);
	}

	vlib_put_next_frame (vm, node, next_index, n_left_to_next);
	}

	apif->next_rx_frame = rx_frame;

	vlib_increment_combined_counter
	(vnet_get_main ()->interface_main.combined_sw_if_counters
	+ VNET_INTERFACE_COUNTER_RX,
	vlib_get_thread_index (), apif->hw_if_index, n_rx_packets, n_rx_bytes);

	vnet_device_increment_rx_packets (thread_index, n_rx_packets);
	return n_rx_packets;
	}

	static uword
	af_packet_input_fn (vlib_main_t * vm, vlib_node_runtime_t * node,
	vlib_frame_t * frame)
	{
	u32 n_rx_packets = 0;
	af_packet_main_t *apm = &af_packet_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)
	{
	af_packet_if_t *apif;
	apif = vec_elt_at_index (apm->interfaces, dq->dev_instance);
	if (apif->is_admin_up)
	n_rx_packets += af_packet_device_input_fn (vm, node, frame, apif);
	}

	return n_rx_packets;
	}

	/* INDENT-OFF */
	VLIB_REGISTER_NODE (af_packet_input_node) = {
	.function = af_packet_input_fn,
	.name = "af-packet-input",
	.sibling_of = "device-input",
	.format_trace = format_af_packet_input_trace,
	.type = VLIB_NODE_TYPE_INPUT,
	.state = VLIB_NODE_STATE_INTERRUPT,
	.n_errors = AF_PACKET_INPUT_N_ERROR,
	.error_strings = af_packet_input_error_strings,
	};

	VLIB_NODE_FUNCTION_MULTIARCH (af_packet_input_node, af_packet_input_fn)
	/* INDENT-ON */


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