aboutsummaryrefslogtreecommitdiffstats
path: root/src/plugins/dpdk/device/node.c
blob: 74fb8da1f2e184a3c9205310f7dcf1a9539e7d62 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
/*
 * Copyright (c) 2015 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 <vnet/vnet.h>
#include <vppinfra/vec.h>
#include <vppinfra/error.h>
#include <vppinfra/format.h>
#include <vppinfra/xxhash.h>

#include <vnet/ethernet/ethernet.h>
#include <dpdk/device/dpdk.h>
#include <vnet/classify/vnet_classify.h>
#include <vnet/mpls/packet.h>
#include <vnet/handoff.h>
#include <vnet/devices/devices.h>
#include <vnet/feature/feature.h>

#include <dpdk/device/dpdk_priv.h>

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

always_inline int
vlib_buffer_is_ip4 (vlib_buffer_t * b)
{
  ethernet_header_t *h = (ethernet_header_t *) vlib_buffer_get_current (b);
  return (h->type == clib_host_to_net_u16 (ETHERNET_TYPE_IP4));
}

always_inline int
vlib_buffer_is_ip6 (vlib_buffer_t * b)
{
  ethernet_header_t *h = (ethernet_header_t *) vlib_buffer_get_current (b);
  return (h->type == clib_host_to_net_u16 (ETHERNET_TYPE_IP6));
}

always_inline int
vlib_buffer_is_mpls (vlib_buffer_t * b)
{
  ethernet_header_t *h = (ethernet_header_t *) vlib_buffer_get_current (b);
  return (h->type == clib_host_to_net_u16 (ETHERNET_TYPE_MPLS));
}

always_inline u32
dpdk_rx_next_from_etype (struct rte_mbuf * mb, vlib_buffer_t * b0)
{
  if (PREDICT_TRUE (vlib_buffer_is_ip4 (b0)))
    {
      if (PREDICT_TRUE ((mb->ol_flags & PKT_RX_IP_CKSUM_GOOD) != 0))
	return VNET_DEVICE_INPUT_NEXT_IP4_NCS_INPUT;
      else
	return VNET_DEVICE_INPUT_NEXT_IP4_INPUT;
    }
  else if (PREDICT_TRUE (vlib_buffer_is_ip6 (b0)))
    return VNET_DEVICE_INPUT_NEXT_IP6_INPUT;
  else if (PREDICT_TRUE (vlib_buffer_is_mpls (b0)))
    return VNET_DEVICE_INPUT_NEXT_MPLS_INPUT;
  else
    return VNET_DEVICE_INPUT_NEXT_ETHERNET_INPUT;
}

always_inline u32
dpdk_rx_next_from_packet_start (struct rte_mbuf * mb, vlib_buffer_t * b0)
{
  word start_delta;
  int rv;

  start_delta = b0->current_data -
    ((mb->buf_addr + mb->data_off) - (void *) b0->data);

  vlib_buffer_advance (b0, -start_delta);

  if (PREDICT_TRUE (vlib_buffer_is_ip4 (b0)))
    {
      if (PREDICT_TRUE ((mb->ol_flags & PKT_RX_IP_CKSUM_GOOD) != 0))
	rv = VNET_DEVICE_INPUT_NEXT_IP4_NCS_INPUT;
      else
	rv = VNET_DEVICE_INPUT_NEXT_IP4_INPUT;
    }
  else if (PREDICT_TRUE (vlib_buffer_is_ip6 (b0)))
    rv = VNET_DEVICE_INPUT_NEXT_IP6_INPUT;
  else if (PREDICT_TRUE (vlib_buffer_is_mpls (b0)))
    rv = VNET_DEVICE_INPUT_NEXT_MPLS_INPUT;
  else
    rv = VNET_DEVICE_INPUT_NEXT_ETHERNET_INPUT;

  vlib_buffer_advance (b0, start_delta);
  return rv;
}

always_inline void
dpdk_rx_error_from_mb (struct rte_mbuf *mb, u32 * next, u8 * error)
{
  if (mb->ol_flags & PKT_RX_IP_CKSUM_BAD)
    {
      *error = DPDK_ERROR_IP_CHECKSUM_ERROR;
      *next = VNET_DEVICE_INPUT_NEXT_DROP;
    }
  else
    *error = DPDK_ERROR_NONE;
}

static void
dpdk_rx_trace (dpdk_main_t * dm,
	       vlib_node_runtime_t * node,
	       dpdk_device_t * xd,
	       u16 queue_id, u32 * buffers, uword n_buffers)
{
  vlib_main_t *vm = vlib_get_main ();
  u32 *b, n_left;
  u32 next0;

  n_left = n_buffers;
  b = buffers;

  while (n_left >= 1)
    {
      u32 bi0;
      vlib_buffer_t *b0;
      dpdk_rx_dma_trace_t *t0;
      struct rte_mbuf *mb;
      u8 error0;

      bi0 = b[0];
      n_left -= 1;

      b0 = vlib_get_buffer (vm, bi0);
      mb = rte_mbuf_from_vlib_buffer (b0);

      if (PREDICT_FALSE (xd->per_interface_next_index != ~0))
	next0 = xd->per_interface_next_index;
      else
	next0 = dpdk_rx_next_from_packet_start (mb, b0);

      dpdk_rx_error_from_mb (mb, &next0, &error0);

      vlib_trace_buffer (vm, node, next0, b0, /* follow_chain */ 0);
      t0 = vlib_add_trace (vm, node, b0, sizeof (t0[0]));
      t0->queue_index = queue_id;
      t0->device_index = xd->device_index;
      t0->buffer_index = bi0;

      clib_memcpy (&t0->mb, mb, sizeof (t0->mb));
      clib_memcpy (&t0->buffer, b0, sizeof (b0[0]) - sizeof (b0->pre_data));
      clib_memcpy (t0->buffer.pre_data, b0->data,
		   sizeof (t0->buffer.pre_data));
      clib_memcpy (&t0->data, mb->buf_addr + mb->data_off, sizeof (t0->data));

      b += 1;
    }
}

static inline u32
dpdk_rx_burst (dpdk_main_t * dm, dpdk_device_t * xd, u16 queue_id)
{
  u32 n_buffers;
  u32 n_left;
  u32 n_this_chunk;

  n_left = VLIB_FRAME_SIZE;
  n_buffers = 0;

  if (PREDICT_TRUE (xd->flags & DPDK_DEVICE_FLAG_PMD))
    {
      while (n_left)
	{
	  n_this_chunk = rte_eth_rx_burst (xd->device_index, queue_id,
					   xd->rx_vectors[queue_id] +
					   n_buffers, n_left);
	  n_buffers += n_this_chunk;
	  n_left -= n_this_chunk;

	  /* Empirically, DPDK r1.8 produces vectors w/ 32 or fewer elts */
	  if (n_this_chunk < 32)
	    break;
	}
    }
  else
    {
      ASSERT (0);
    }

  return n_buffers;
}


static_always_inline void
dpdk_process_subseq_segs (vlib_main_t * vm, vlib_buffer_t * b,
			  struct rte_mbuf *mb, vlib_buffer_free_list_t * fl)
{
  u8 nb_seg = 1;
  struct rte_mbuf *mb_seg = 0;
  vlib_buffer_t *b_seg, *b_chain = 0;
  mb_seg = mb->next;
  b_chain = b;

  if (mb->nb_segs < 2)
    return;

  b->flags |= VLIB_BUFFER_TOTAL_LENGTH_VALID;
  b->total_length_not_including_first_buffer = 0;

  while (nb_seg < mb->nb_segs)
    {
      ASSERT (mb_seg != 0);

      b_seg = vlib_buffer_from_rte_mbuf (mb_seg);
      vlib_buffer_init_for_free_list (b_seg, fl);

      ASSERT ((b_seg->flags & VLIB_BUFFER_NEXT_PRESENT) == 0);
      ASSERT (b_seg->current_data == 0);

      /*
       * The driver (e.g. virtio) may not put the packet data at the start
       * of the segment, so don't assume b_seg->current_data == 0 is correct.
       */
      b_seg->current_data =
	(mb_seg->buf_addr + mb_seg->data_off) - (void *) b_seg->data;

      b_seg->current_length = mb_seg->data_len;
      b->total_length_not_including_first_buffer += mb_seg->data_len;

      b_chain->flags |= VLIB_BUFFER_NEXT_PRESENT;
      b_chain->next_buffer = vlib_get_buffer_index (vm, b_seg);

      b_chain = b_seg;
      mb_seg = mb_seg->next;
      nb_seg++;
    }
}

static_always_inline void
dpdk_prefetch_buffer (struct rte_mbuf *mb)
{
  vlib_buffer_t *b = vlib_buffer_from_rte_mbuf (mb);
  CLIB_PREFETCH (mb, CLIB_CACHE_LINE_BYTES, LOAD);
  CLIB_PREFETCH (b, CLIB_CACHE_LINE_BYTES, STORE);
}

static_always_inline void
dpdk_prefetch_ethertype (struct rte_mbuf *mb)
{
  CLIB_PREFETCH (mb->buf_addr + mb->data_off +
		 STRUCT_OFFSET_OF (ethernet_header_t, type),
		 CLIB_CACHE_LINE_BYTES, LOAD);
}


/*
   This function should fill 1st cacheline of vlib_buffer_t metadata with data
   from buffer template. Instead of filling field by field, we construct
   template and then use 128/256 bit vector instruction to copy data.
   This code first loads whole cacheline into 4 128-bit registers (xmm)
   or two 256 bit registers (ymm) and then stores data into all 4 buffers
   efectively saving on register load operations.
*/

static_always_inline void
dpdk_buffer_init_from_template (void *d0, void *d1, void *d2, void *d3,
				void *s)
{
#if defined(CLIB_HAVE_VEC128)
  int i;
  for (i = 0; i < 2; i++)
    {
      *(u8x32 *) (((u8 *) d0) + i * 32) =
	*(u8x32 *) (((u8 *) d1) + i * 32) =
	*(u8x32 *) (((u8 *) d2) + i * 32) =
	*(u8x32 *) (((u8 *) d3) + i * 32) = *(u8x32 *) (((u8 *) s) + i * 32);
    }
#elif defined(CLIB_HAVE_VEC64)
  int i;
  for (i = 0; i < 4; i++)
    {
      *(u8x16 *) (((u8 *) d0) + i * 16) =
	*(u8x16 *) (((u8 *) d1) + i * 16) =
	*(u8x16 *) (((u8 *) d2) + i * 16) =
	*(u8x16 *) (((u8 *) d3) + i * 16) = *(u8x16 *) (((u8 *) s) + i * 16);
    }
#else
#error "Either CLIB_HAVE_VEC128 or CLIB_HAVE_VEC64 has to be defined"
#endif
}

/*
 * This function is used when there are no worker threads.
 * The main thread performs IO and forwards the packets.
 */
static_always_inline u32
dpdk_device_input (dpdk_main_t * dm, dpdk_device_t * xd,
		   vlib_node_runtime_t * node, u32 thread_index, u16 queue_id,
		   int maybe_multiseg)
{
  u32 n_buffers;
  u32 next_index = VNET_DEVICE_INPUT_NEXT_ETHERNET_INPUT;
  u32 n_left_to_next, *to_next;
  u32 mb_index;
  vlib_main_t *vm = vlib_get_main ();
  uword n_rx_bytes = 0;
  u32 n_trace, trace_cnt __attribute__ ((unused));
  vlib_buffer_free_list_t *fl;
  vlib_buffer_t *bt = vec_elt_at_index (dm->buffer_templates, thread_index);

  if ((xd->flags & DPDK_DEVICE_FLAG_ADMIN_UP) == 0)
    return 0;

  n_buffers = dpdk_rx_burst (dm, xd, queue_id);

  if (n_buffers == 0)
    {
      return 0;
    }

  vec_reset_length (xd->d_trace_buffers[thread_index]);
  trace_cnt = n_trace = vlib_get_trace_count (vm, node);

  if (n_trace > 0)
    {
      u32 n = clib_min (n_trace, n_buffers);
      mb_index = 0;

      while (n--)
	{
	  struct rte_mbuf *mb = xd->rx_vectors[queue_id][mb_index++];
	  vlib_buffer_t *b = vlib_buffer_from_rte_mbuf (mb);
	  vec_add1 (xd->d_trace_buffers[thread_index],
		    vlib_get_buffer_index (vm, b));
	}
    }

  fl = vlib_buffer_get_free_list (vm, VLIB_BUFFER_DEFAULT_FREE_LIST_INDEX);

  /* Update buffer template */
  vnet_buffer (bt)->sw_if_index[VLIB_RX] = xd->vlib_sw_if_index;
  bt->error = node->errors[DPDK_ERROR_NONE];

  mb_index = 0;

  while (n_buffers > 0)
    {
      vlib_buffer_t *b0, *b1, *b2, *b3;
      u32 bi0, next0;
      u32 bi1, next1;
      u32 bi2, next2;
      u32 bi3, next3;
      u8 error0, error1, error2, error3;
      u64 or_ol_flags;

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

      while (n_buffers >= 12 && n_left_to_next >= 4)
	{
	  struct rte_mbuf *mb0, *mb1, *mb2, *mb3;

	  /* prefetches are interleaved with the rest of the code to reduce
	     pressure on L1 cache */
	  dpdk_prefetch_buffer (xd->rx_vectors[queue_id][mb_index + 8]);
	  dpdk_prefetch_ethertype (xd->rx_vectors[queue_id][mb_index + 4]);

	  mb0 = xd->rx_vectors[queue_id][mb_index];
	  mb1 = xd->rx_vectors[queue_id][mb_index + 1];
	  mb2 = xd->rx_vectors[queue_id][mb_index + 2];
	  mb3 = xd->rx_vectors[queue_id][mb_index + 3];

	  ASSERT (mb0);
	  ASSERT (mb1);
	  ASSERT (mb2);
	  ASSERT (mb3);

	  if (maybe_multiseg)
	    {
	      if (PREDICT_FALSE (mb0->nb_segs > 1))
		dpdk_prefetch_buffer (mb0->next);
	      if (PREDICT_FALSE (mb1->nb_segs > 1))
		dpdk_prefetch_buffer (mb1->next);
	      if (PREDICT_FALSE (mb2->nb_segs > 1))
		dpdk_prefetch_buffer (mb2->next);
	      if (PREDICT_FALSE (mb3->nb_segs > 1))
		dpdk_prefetch_buffer (mb3->next);
	    }

	  b0 = vlib_buffer_from_rte_mbuf (mb0);
	  b1 = vlib_buffer_from_rte_mbuf (mb1);
	  b2 = vlib_buffer_from_rte_mbuf (mb2);
	  b3 = vlib_buffer_from_rte_mbuf (mb3);

	  dpdk_buffer_init_from_template (b0, b1, b2, b3, bt);

	  dpdk_prefetch_buffer (xd->rx_vectors[queue_id][mb_index + 9]);
	  dpdk_prefetch_ethertype (xd->rx_vectors[queue_id][mb_index + 5]);

	  /* current_data must be set to -RTE_PKTMBUF_HEADROOM in template */
	  b0->current_data += mb0->data_off;
	  b1->current_data += mb1->data_off;
	  b2->current_data += mb2->data_off;
	  b3->current_data += mb3->data_off;

	  b0->current_length = mb0->data_len;
	  b1->current_length = mb1->data_len;
	  b2->current_length = mb2->data_len;
	  b3->current_length = mb3->data_len;

	  dpdk_prefetch_buffer (xd->rx_vectors[queue_id][mb_index + 10]);
	  dpdk_prefetch_ethertype (xd->rx_vectors[queue_id][mb_index + 7]);

	  bi0 = vlib_get_buffer_index (vm, b0);
	  bi1 = vlib_get_buffer_index (vm, b1);
	  bi2 = vlib_get_buffer_index (vm, b2);
	  bi3 = vlib_get_buffer_index (vm, b3);

	  to_next[0] = bi0;
	  to_next[1] = bi1;
	  to_next[2] = bi2;
	  to_next[3] = bi3;
	  to_next += 4;
	  n_left_to_next -= 4;

	  if (PREDICT_FALSE (xd->per_interface_next_index != ~0))
	    {
	      next0 = next1 = next2 = next3 = xd->per_interface_next_index;
	    }
	  else
	    {
	      next0 = dpdk_rx_next_from_etype (mb0, b0);
	      next1 = dpdk_rx_next_from_etype (mb1, b1);
	      next2 = dpdk_rx_next_from_etype (mb2, b2);
	      next3 = dpdk_rx_next_from_etype (mb3, b3);
	    }

	  dpdk_prefetch_buffer (xd->rx_vectors[queue_id][mb_index + 11]);
	  dpdk_prefetch_ethertype (xd->rx_vectors[queue_id][mb_index + 6]);

	  or_ol_flags = (mb0->ol_flags | mb1->ol_flags |
			 mb2->ol_flags | mb3->ol_flags);
	  if (PREDICT_FALSE (or_ol_flags & PKT_RX_IP_CKSUM_BAD))
	    {
	      dpdk_rx_error_from_mb (mb0, &next0, &error0);
	      dpdk_rx_error_from_mb (mb1, &next1, &error1);
	      dpdk_rx_error_from_mb (mb2, &next2, &error2);
	      dpdk_rx_error_from_mb (mb3, &next3, &error3);
	      b0->error = node->errors[error0];
	      b1->error = node->errors[error1];
	      b2->error = node->errors[error2];
	      b3->error = node->errors[error3];
	    }

	  vlib_buffer_advance (b0, device_input_next_node_advance[next0]);
	  vlib_buffer_advance (b1, device_input_next_node_advance[next1]);
	  vlib_buffer_advance (b2, device_input_next_node_advance[next2]);
	  vlib_buffer_advance (b3, device_input_next_node_advance[next3]);

	  n_rx_bytes += mb0->pkt_len;
	  n_rx_bytes += mb1->pkt_len;
	  n_rx_bytes += mb2->pkt_len;
	  n_rx_bytes += mb3->pkt_len;

	  /* Process subsequent segments of multi-segment packets */
	  if (maybe_multiseg)
	    {
	      dpdk_process_subseq_segs (vm, b0, mb0, fl);
	      dpdk_process_subseq_segs (vm, b1, mb1, fl);
	      dpdk_process_subseq_segs (vm, b2, mb2, fl);
	      dpdk_process_subseq_segs (vm, b3, mb3, fl);
	    }

	  /*
	   * Turn this on if you run into
	   * "bad monkey" contexts, and you want to know exactly
	   * which nodes they've visited... See main.c...
	   */
	  VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b0);
	  VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b1);
	  VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b2);
	  VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b3);

	  /* Do we have any driver RX features configured on the interface? */
	  vnet_feature_start_device_input_x4 (xd->vlib_sw_if_index,
					      &next0, &next1, &next2, &next3,
					      b0, b1, b2, b3);

	  vlib_validate_buffer_enqueue_x4 (vm, node, next_index,
					   to_next, n_left_to_next,
					   bi0, bi1, bi2, bi3,
					   next0, next1, next2, next3);
	  n_buffers -= 4;
	  mb_index += 4;
	}
      while (n_buffers > 0 && n_left_to_next > 0)
	{
	  struct rte_mbuf *mb0 = xd->rx_vectors[queue_id][mb_index];

	  if (PREDICT_TRUE (n_buffers > 3))
	    {
	      dpdk_prefetch_buffer (xd->rx_vectors[queue_id][mb_index + 2]);
	      dpdk_prefetch_ethertype (xd->rx_vectors[queue_id]
				       [mb_index + 1]);
	    }

	  ASSERT (mb0);

	  b0 = vlib_buffer_from_rte_mbuf (mb0);

	  /* Prefetch one next segment if it exists. */
	  if (PREDICT_FALSE (mb0->nb_segs > 1))
	    dpdk_prefetch_buffer (mb0->next);

	  clib_memcpy (b0, bt, CLIB_CACHE_LINE_BYTES);

	  ASSERT (b0->current_data == -RTE_PKTMBUF_HEADROOM);
	  b0->current_data += mb0->data_off;
	  b0->current_length = mb0->data_len;

	  bi0 = vlib_get_buffer_index (vm, b0);

	  to_next[0] = bi0;
	  to_next++;
	  n_left_to_next--;

	  if (PREDICT_FALSE (xd->per_interface_next_index != ~0))
	    next0 = xd->per_interface_next_index;
	  else
	    next0 = dpdk_rx_next_from_etype (mb0, b0);

	  dpdk_rx_error_from_mb (mb0, &next0, &error0);
	  b0->error = node->errors[error0];

	  vlib_buffer_advance (b0, device_input_next_node_advance[next0]);

	  n_rx_bytes += mb0->pkt_len;

	  /* Process subsequent segments of multi-segment packets */
	  dpdk_process_subseq_segs (vm, b0, mb0, fl);

	  /*
	   * Turn this on if you run into
	   * "bad monkey" contexts, and you want to know exactly
	   * which nodes they've visited... See main.c...
	   */
	  VLIB_BUFFER_TRACE_TRAJECTORY_INIT (b0);

	  /* Do we have any driver RX features configured on the interface? */
	  vnet_feature_start_device_input_x1 (xd->vlib_sw_if_index, &next0,
					      b0);

	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index,
					   to_next, n_left_to_next,
					   bi0, next0);
	  n_buffers--;
	  mb_index++;
	}
      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }

  if (PREDICT_FALSE (vec_len (xd->d_trace_buffers[thread_index]) > 0))
    {
      dpdk_rx_trace (dm, node, xd, queue_id,
		     xd->d_trace_buffers[thread_index],
		     vec_len (xd->d_trace_buffers[thread_index]));
      vlib_set_trace_count (vm, node,
			    n_trace -
			    vec_len (xd->d_trace_buffers[thread_index]));
    }

  vlib_increment_combined_counter
    (vnet_get_main ()->interface_main.combined_sw_if_counters
     + VNET_INTERFACE_COUNTER_RX,
     thread_index, xd->vlib_sw_if_index, mb_index, n_rx_bytes);

  vnet_device_increment_rx_packets (thread_index, mb_index);

  return mb_index;
}

static inline void
poll_rate_limit (dpdk_main_t * dm)
{
  /* Limit the poll rate by sleeping for N msec between polls */
  if (PREDICT_FALSE (dm->poll_sleep_usec != 0))
    {
      struct timespec ts, tsrem;

      ts.tv_sec = 0;
      ts.tv_nsec = 1000 * dm->poll_sleep_usec;

      while (nanosleep (&ts, &tsrem) < 0)
	{
	  ts = tsrem;
	}
    }
}

/** \brief Main DPDK input node
    @node dpdk-input

    This is the main DPDK input node: across each assigned interface,
    call rte_eth_rx_burst(...) or similar to obtain a vector of
    packets to process. Handle early packet discard. Derive @c
    vlib_buffer_t metadata from <code>struct rte_mbuf</code> metadata,
    Depending on the resulting metadata: adjust <code>b->current_data,
    b->current_length </code> and dispatch directly to
    ip4-input-no-checksum, or ip6-input. Trace the packet if required.

    @param vm   vlib_main_t corresponding to the current thread
    @param node vlib_node_runtime_t
    @param f    vlib_frame_t input-node, not used.

    @par Graph mechanics: buffer metadata, next index usage

    @em Uses:
    - <code>struct rte_mbuf mb->ol_flags</code>
        - PKT_RX_IP_CKSUM_BAD
    - <code> RTE_ETH_IS_xxx_HDR(mb->packet_type) </code>
        - packet classification result

    @em Sets:
    - <code>b->error</code> if the packet is to be dropped immediately
    - <code>b->current_data, b->current_length</code>
        - adjusted as needed to skip the L2 header in  direct-dispatch cases
    - <code>vnet_buffer(b)->sw_if_index[VLIB_RX]</code>
        - rx interface sw_if_index
    - <code>vnet_buffer(b)->sw_if_index[VLIB_TX] = ~0</code>
        - required by ipX-lookup
    - <code>b->flags</code>
        - to indicate multi-segment pkts (VLIB_BUFFER_NEXT_PRESENT), etc.

    <em>Next Nodes:</em>
    - Static arcs to: error-drop, ethernet-input,
      ip4-input-no-checksum, ip6-input, mpls-input
    - per-interface redirection, controlled by
      <code>xd->per_interface_next_index</code>
*/

static uword
dpdk_input (vlib_main_t * vm, vlib_node_runtime_t * node, vlib_frame_t * f)
{
  dpdk_main_t *dm = &dpdk_main;
  dpdk_device_t *xd;
  uword n_rx_packets = 0;
  vnet_device_input_runtime_t *rt = (void *) node->runtime_data;
  vnet_device_and_queue_t *dq;
  u32 thread_index = node->thread_index;

  /*
   * Poll all devices on this cpu for input/interrupts.
   */
  /* *INDENT-OFF* */
  foreach_device_and_queue (dq, rt->devices_and_queues)
    {
      xd = vec_elt_at_index(dm->devices, dq->dev_instance);
      if (xd->flags & DPDK_DEVICE_FLAG_MAYBE_MULTISEG)
        n_rx_packets += dpdk_device_input (dm, xd, node, thread_index, dq->queue_id, /* maybe_multiseg */ 1);
      else
        n_rx_packets += dpdk_device_input (dm, xd, node, thread_index, dq->queue_id, /* maybe_multiseg */ 0);
    }
  /* *INDENT-ON* */

  poll_rate_limit (dm);

  return n_rx_packets;
}

/* *INDENT-OFF* */
VLIB_REGISTER_NODE (dpdk_input_node) = {
  .function = dpdk_input,
  .type = VLIB_NODE_TYPE_INPUT,
  .name = "dpdk-input",
  .sibling_of = "device-input",

  /* Will be enabled if/when hardware is detected. */
  .state = VLIB_NODE_STATE_DISABLED,

  .format_buffer = format_ethernet_header_with_length,
  .format_trace = format_dpdk_rx_dma_trace,

  .n_errors = DPDK_N_ERROR,
  .error_strings = dpdk_error_strings,
};

VLIB_NODE_FUNCTION_MULTIARCH (dpdk_input_node, dpdk_input);
/* *INDENT-ON* */

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