aboutsummaryrefslogtreecommitdiffstats
path: root/src/vnet/gso/node.c
blob: c48d8fefe16532ac6cb7e4a13b1396694c1c015b (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
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
/*
 * Copyright (c) 2018 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 <vlib/vlib.h>
#include <vnet/vnet.h>
#include <vppinfra/error.h>
#include <vnet/ethernet/ethernet.h>
#include <vnet/feature/feature.h>
#include <vnet/gso/gso.h>
#include <vnet/gso/hdr_offset_parser.h>
#include <vnet/ip/icmp46_packet.h>
#include <vnet/ip/ip4.h>
#include <vnet/ip/ip6.h>
#include <vnet/udp/udp_packet.h>

#define foreach_gso_error                                                     \
  _ (NO_BUFFERS, "no buffers to segment GSO")                                 \
  _ (UNHANDLED_TYPE, "unhandled gso type")

static char *gso_error_strings[] = {
#define _(sym, string) string,
  foreach_gso_error
#undef _
};

typedef enum
{
#define _(sym, str) GSO_ERROR_##sym,
  foreach_gso_error
#undef _
    GSO_N_ERROR,
} gso_error_t;

typedef enum
{
  GSO_NEXT_DROP,
  GSO_N_NEXT,
} gso_next_t;

typedef struct
{
  u32 flags;
  u16 gso_size;
  u8 gso_l4_hdr_sz;
  generic_header_offset_t gho;
} gso_trace_t;

static u8 *
format_gso_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 *);
  gso_trace_t *t = va_arg (*args, gso_trace_t *);

  if (t->flags & VNET_BUFFER_F_GSO)
    {
      s = format (s, "gso_sz %d gso_l4_hdr_sz %d\n%U",
		  t->gso_size, t->gso_l4_hdr_sz, format_generic_header_offset,
		  &t->gho);
    }
  else
    {
      s =
	format (s, "non-gso buffer\n%U", format_generic_header_offset,
		&t->gho);
    }

  return s;
}

static_always_inline u16
tso_segment_ipip_tunnel_fixup (vlib_main_t * vm,
			       vnet_interface_per_thread_data_t * ptd,
			       vlib_buffer_t * sb0,
			       generic_header_offset_t * gho)
{
  u16 n_tx_bufs = vec_len (ptd->split_buffers);
  u16 i = 0, n_tx_bytes = 0;

  while (i < n_tx_bufs)
    {
      vlib_buffer_t *b0 = vlib_get_buffer (vm, ptd->split_buffers[i]);
      vnet_get_outer_header (b0, gho);
      clib_memcpy_fast (vlib_buffer_get_current (b0),
			vlib_buffer_get_current (sb0), gho->outer_hdr_sz);

      ip4_header_t *ip4 =
	(ip4_header_t *) (vlib_buffer_get_current (b0) +
			  gho->outer_l3_hdr_offset);
      ip6_header_t *ip6 =
	(ip6_header_t *) (vlib_buffer_get_current (b0) +
			  gho->outer_l3_hdr_offset);

      if (gho->gho_flags & GHO_F_OUTER_IP4)
	{
	  ip4->length =
	    clib_host_to_net_u16 (b0->current_length -
				  gho->outer_l3_hdr_offset);
	  ip4->checksum = ip4_header_checksum (ip4);
	}
      else if (gho->gho_flags & GHO_F_OUTER_IP6)
	{
	  ip6->payload_length =
	    clib_host_to_net_u16 (b0->current_length -
				  gho->outer_l4_hdr_offset);
	}

      n_tx_bytes += gho->outer_hdr_sz;
      i++;
    }
  return n_tx_bytes;
}

static_always_inline void
tso_segment_vxlan_tunnel_headers_fixup (vlib_main_t * vm, vlib_buffer_t * b,
					generic_header_offset_t * gho)
{
  u8 proto = 0;
  ip4_header_t *ip4 = 0;
  ip6_header_t *ip6 = 0;
  udp_header_t *udp = 0;

  ip4 =
    (ip4_header_t *) (vlib_buffer_get_current (b) + gho->outer_l3_hdr_offset);
  ip6 =
    (ip6_header_t *) (vlib_buffer_get_current (b) + gho->outer_l3_hdr_offset);
  udp =
    (udp_header_t *) (vlib_buffer_get_current (b) + gho->outer_l4_hdr_offset);

  if (gho->gho_flags & GHO_F_OUTER_IP4)
    {
      proto = ip4->protocol;
      ip4->length =
	clib_host_to_net_u16 (b->current_length - gho->outer_l3_hdr_offset);
      ip4->checksum = ip4_header_checksum (ip4);
    }
  else if (gho->gho_flags & GHO_F_OUTER_IP6)
    {
      proto = ip6->protocol;
      ip6->payload_length =
	clib_host_to_net_u16 (b->current_length - gho->outer_l4_hdr_offset);
    }
  if (proto == IP_PROTOCOL_UDP)
    {
      int bogus;
      udp->length =
	clib_host_to_net_u16 (b->current_length - gho->outer_l4_hdr_offset);
      udp->checksum = 0;
      if (gho->gho_flags & GHO_F_OUTER_IP6)
	{
	  udp->checksum =
	    ip6_tcp_udp_icmp_compute_checksum (vm, b, ip6, &bogus);
	}
      else if (gho->gho_flags & GHO_F_OUTER_IP4)
	{
	  udp->checksum = ip4_tcp_udp_compute_checksum (vm, b, ip4);
	}
      /* FIXME: it should be OUTER_UDP_CKSUM */
      vnet_buffer_offload_flags_clear (b, VNET_BUFFER_OFFLOAD_F_UDP_CKSUM);
    }
}

static_always_inline u16
tso_segment_vxlan_tunnel_fixup (vlib_main_t * vm,
				vnet_interface_per_thread_data_t * ptd,
				vlib_buffer_t * sb0,
				generic_header_offset_t * gho)
{
  u16 n_tx_bufs = vec_len (ptd->split_buffers);
  u16 i = 0, n_tx_bytes = 0;

  while (i < n_tx_bufs)
    {
      vlib_buffer_t *b0 = vlib_get_buffer (vm, ptd->split_buffers[i]);
      vnet_get_outer_header (b0, gho);
      clib_memcpy_fast (vlib_buffer_get_current (b0),
			vlib_buffer_get_current (sb0), gho->outer_hdr_sz);

      tso_segment_vxlan_tunnel_headers_fixup (vm, b0, gho);
      n_tx_bytes += gho->outer_hdr_sz;
      i++;
    }
  return n_tx_bytes;
}

static_always_inline u16
tso_alloc_tx_bufs (vlib_main_t * vm,
		   vnet_interface_per_thread_data_t * ptd,
		   vlib_buffer_t * b0, u32 n_bytes_b0, u16 l234_sz,
		   u16 gso_size, u16 first_data_size,
		   generic_header_offset_t * gho)
{
  u16 n_alloc, size;
  u16 first_packet_length = l234_sz + first_data_size;

  /*
   * size is the amount of data per segmented buffer except the 1st
   * segmented buffer.
   * l2_hdr_offset is an offset == current_data of vlib_buffer_t.
   * l234_sz is hdr_sz from l2_hdr_offset.
   */
  size =
    clib_min (gso_size, vlib_buffer_get_default_data_size (vm) - l234_sz
	      - gho->l2_hdr_offset);

  /*
   * First segmented buffer length is calculated separately.
   * As it may contain less data than gso_size (when gso_size is
   * greater than current_length of 1st buffer from GSO chained
   * buffers) and/or size calculated above.
   */
  u16 n_bufs = 1;

  /*
   * Total packet length minus first packet length including l234 header.
   * rounded-up division
   */
  ASSERT (n_bytes_b0 > first_packet_length);
  n_bufs += ((n_bytes_b0 - first_packet_length + (size - 1)) / size);

  vec_validate (ptd->split_buffers, n_bufs - 1);

  n_alloc = vlib_buffer_alloc (vm, ptd->split_buffers, n_bufs);
  if (n_alloc < n_bufs)
    {
      vlib_buffer_free (vm, ptd->split_buffers, n_alloc);
      return 0;
    }
  return n_alloc;
}

static_always_inline void
tso_init_buf_from_template_base (vlib_buffer_t * nb0, vlib_buffer_t * b0,
				 u32 flags, u16 length)
{
  /* copying objects from cacheline 0 */
  nb0->current_data = b0->current_data;
  nb0->current_length = length;
  nb0->flags = VLIB_BUFFER_TOTAL_LENGTH_VALID | flags;
  nb0->flow_id = b0->flow_id;
  nb0->error = b0->error;
  nb0->current_config_index = b0->current_config_index;
  clib_memcpy_fast (&nb0->opaque, &b0->opaque, sizeof (nb0->opaque));

  /* copying objects from cacheline 1 */
  nb0->trace_handle = b0->trace_handle;
  nb0->total_length_not_including_first_buffer = 0;

  /* copying data */
  clib_memcpy_fast (vlib_buffer_get_current (nb0),
		    vlib_buffer_get_current (b0), length);
}

static_always_inline void
tso_init_buf_from_template (vlib_main_t * vm, vlib_buffer_t * nb0,
			    vlib_buffer_t * b0, u16 template_data_sz,
			    u16 gso_size, u8 ** p_dst_ptr, u16 * p_dst_left,
			    u32 next_tcp_seq, u32 flags,
			    generic_header_offset_t * gho)
{
  tso_init_buf_from_template_base (nb0, b0, flags, template_data_sz);

  *p_dst_left =
    clib_min (gso_size,
	      vlib_buffer_get_default_data_size (vm) - (template_data_sz +
							nb0->current_data));
  *p_dst_ptr = vlib_buffer_get_current (nb0) + template_data_sz;

  tcp_header_t *tcp =
    (tcp_header_t *) (vlib_buffer_get_current (nb0) + gho->l4_hdr_offset);
  tcp->seq_number = clib_host_to_net_u32 (next_tcp_seq);
}

static_always_inline void
tso_fixup_segmented_buf (vlib_main_t * vm, vlib_buffer_t * b0, u8 tcp_flags,
			 int is_l2, int is_ip6, generic_header_offset_t * gho)
{
  ip4_header_t *ip4 =
    (ip4_header_t *) (vlib_buffer_get_current (b0) + gho->l3_hdr_offset);
  ip6_header_t *ip6 =
    (ip6_header_t *) (vlib_buffer_get_current (b0) + gho->l3_hdr_offset);
  tcp_header_t *tcp =
    (tcp_header_t *) (vlib_buffer_get_current (b0) + gho->l4_hdr_offset);

  tcp->flags = tcp_flags;

  if (is_ip6)
    {
      ip6->payload_length =
	clib_host_to_net_u16 (b0->current_length - gho->l4_hdr_offset);
      if (gho->gho_flags & GHO_F_TCP)
	{
	  int bogus = 0;
	  tcp->checksum = 0;
	  tcp->checksum =
	    ip6_tcp_udp_icmp_compute_checksum (vm, b0, ip6, &bogus);
	  vnet_buffer_offload_flags_clear (b0,
					   VNET_BUFFER_OFFLOAD_F_TCP_CKSUM);
	}
    }
  else
    {
      ip4->length =
	clib_host_to_net_u16 (b0->current_length - gho->l3_hdr_offset);
      if (gho->gho_flags & GHO_F_IP4)
	ip4->checksum = ip4_header_checksum (ip4);
      if (gho->gho_flags & GHO_F_TCP)
	{
	  tcp->checksum = 0;
	  tcp->checksum = ip4_tcp_udp_compute_checksum (vm, b0, ip4);
	}
      vnet_buffer_offload_flags_clear (b0, (VNET_BUFFER_OFFLOAD_F_IP_CKSUM |
					    VNET_BUFFER_OFFLOAD_F_TCP_CKSUM));
    }

  if (!is_l2 && ((gho->gho_flags & GHO_F_TUNNEL) == 0))
    {
      u32 adj_index0 = vnet_buffer (b0)->ip.adj_index[VLIB_TX];

      ip_adjacency_t *adj0 = adj_get (adj_index0);

      if (adj0->lookup_next_index == IP_LOOKUP_NEXT_MIDCHAIN &&
	  adj0->sub_type.midchain.fixup_func)
	/* calls e.g. ipip44_fixup */
	adj0->sub_type.midchain.fixup_func
	  (vm, adj0, b0, adj0->sub_type.midchain.fixup_data);
    }
}

/**
 * Allocate the necessary number of ptd->split_buffers,
 * and segment the possibly chained buffer(s) from b0 into
 * there.
 *
 * Return the cumulative number of bytes sent or zero
 * if allocation failed.
 */

static_always_inline u32
tso_segment_buffer (vlib_main_t * vm, vnet_interface_per_thread_data_t * ptd,
		    u32 sbi0, vlib_buffer_t * sb0,
		    generic_header_offset_t * gho, u32 n_bytes_b0, int is_l2,
		    int is_ip6)
{
  u32 n_tx_bytes = 0;
  u16 gso_size = vnet_buffer2 (sb0)->gso_size;

  u8 save_tcp_flags = 0;
  u8 tcp_flags_no_fin_psh = 0;
  u32 next_tcp_seq = 0;

  tcp_header_t *tcp =
    (tcp_header_t *) (vlib_buffer_get_current (sb0) + gho->l4_hdr_offset);
  next_tcp_seq = clib_net_to_host_u32 (tcp->seq_number);
  /* store original flags for last packet and reset FIN and PSH */
  save_tcp_flags = tcp->flags;
  tcp_flags_no_fin_psh = tcp->flags & ~(TCP_FLAG_FIN | TCP_FLAG_PSH);
  tcp->checksum = 0;

  u32 default_bflags =
    sb0->flags & ~(VNET_BUFFER_F_GSO | VLIB_BUFFER_NEXT_PRESENT);
  u16 l234_sz = gho->hdr_sz;
  int first_data_size = clib_min (gso_size, sb0->current_length - l234_sz);
  next_tcp_seq += first_data_size;

  if (PREDICT_FALSE
      (!tso_alloc_tx_bufs
       (vm, ptd, sb0, n_bytes_b0, l234_sz, gso_size, first_data_size, gho)))
    return 0;

  vlib_buffer_t *b0 = vlib_get_buffer (vm, ptd->split_buffers[0]);
  tso_init_buf_from_template_base (b0, sb0, default_bflags,
				   l234_sz + first_data_size);

  u32 total_src_left = n_bytes_b0 - l234_sz - first_data_size;
  if (total_src_left)
    {
      /* Need to copy more segments */
      u8 *src_ptr, *dst_ptr;
      u16 src_left, dst_left;
      /* current source buffer */
      vlib_buffer_t *csb0 = sb0;
      u32 csbi0 = sbi0;
      /* current dest buffer */
      vlib_buffer_t *cdb0;
      u16 dbi = 1;		/* the buffer [0] is b0 */

      src_ptr = vlib_buffer_get_current (sb0) + l234_sz + first_data_size;
      src_left = sb0->current_length - l234_sz - first_data_size;

      tso_fixup_segmented_buf (vm, b0, tcp_flags_no_fin_psh, is_l2, is_ip6,
			       gho);

      /* grab a second buffer and prepare the loop */
      ASSERT (dbi < vec_len (ptd->split_buffers));
      cdb0 = vlib_get_buffer (vm, ptd->split_buffers[dbi++]);
      tso_init_buf_from_template (vm, cdb0, b0, l234_sz, gso_size, &dst_ptr,
				  &dst_left, next_tcp_seq, default_bflags,
				  gho);

      /* an arbitrary large number to catch the runaway loops */
      int nloops = 2000;
      while (total_src_left)
	{
	  if (nloops-- <= 0)
	    clib_panic ("infinite loop detected");
	  u16 bytes_to_copy = clib_min (src_left, dst_left);

	  clib_memcpy_fast (dst_ptr, src_ptr, bytes_to_copy);

	  src_left -= bytes_to_copy;
	  src_ptr += bytes_to_copy;
	  total_src_left -= bytes_to_copy;
	  dst_left -= bytes_to_copy;
	  dst_ptr += bytes_to_copy;
	  next_tcp_seq += bytes_to_copy;
	  cdb0->current_length += bytes_to_copy;

	  if (0 == src_left)
	    {
	      int has_next = (csb0->flags & VLIB_BUFFER_NEXT_PRESENT);
	      u32 next_bi = csb0->next_buffer;

	      /* init src to the next buffer in chain */
	      if (has_next)
		{
		  csbi0 = next_bi;
		  csb0 = vlib_get_buffer (vm, csbi0);
		  src_left = csb0->current_length;
		  src_ptr = vlib_buffer_get_current (csb0);
		}
	      else
		{
		  ASSERT (total_src_left == 0);
		  break;
		}
	    }
	  if (0 == dst_left && total_src_left)
	    {
	      n_tx_bytes += cdb0->current_length;
	      tso_fixup_segmented_buf (vm, cdb0, tcp_flags_no_fin_psh, is_l2,
				       is_ip6, gho);
	      ASSERT (dbi < vec_len (ptd->split_buffers));
	      cdb0 = vlib_get_buffer (vm, ptd->split_buffers[dbi++]);
	      tso_init_buf_from_template (vm, cdb0, b0, l234_sz,
					  gso_size, &dst_ptr, &dst_left,
					  next_tcp_seq, default_bflags, gho);
	    }
	}

      tso_fixup_segmented_buf (vm, cdb0, save_tcp_flags, is_l2, is_ip6, gho);

      n_tx_bytes += cdb0->current_length;
    }
  n_tx_bytes += b0->current_length;
  return n_tx_bytes;
}

__clib_unused u32
gso_segment_buffer (vlib_main_t *vm, vnet_interface_per_thread_data_t *ptd,
		    u32 bi, vlib_buffer_t *b, generic_header_offset_t *gho,
		    u32 n_bytes_b, u8 is_l2, u8 is_ip6)
{

  return tso_segment_buffer (vm, ptd, bi, b, gho, n_bytes_b, is_l2, is_ip6);
}

static_always_inline void
drop_one_buffer_and_count (vlib_main_t * vm, vnet_main_t * vnm,
			   vlib_node_runtime_t * node, u32 * pbi0,
			   u32 sw_if_index, u32 drop_error_code)
{
  u32 thread_index = vm->thread_index;

  vlib_simple_counter_main_t *cm;
  cm =
    vec_elt_at_index (vnm->interface_main.sw_if_counters,
		      VNET_INTERFACE_COUNTER_TX_ERROR);
  vlib_increment_simple_counter (cm, thread_index, sw_if_index, 1);

  vlib_error_drop_buffers (vm, node, pbi0,
			   /* buffer stride */ 1,
			   /* n_buffers */ 1, GSO_NEXT_DROP, node->node_index,
			   drop_error_code);
}

static_always_inline uword
vnet_gso_node_inline (vlib_main_t * vm,
		      vlib_node_runtime_t * node,
		      vlib_frame_t * frame,
		      vnet_main_t * vnm,
		      vnet_hw_interface_t * hi,
		      int is_l2, int is_ip4, int is_ip6, int do_segmentation)
{
  u32 *to_next;
  u32 next_index = node->cached_next_index;
  u32 *from = vlib_frame_vector_args (frame);
  u32 n_left_from = frame->n_vectors;
  u32 *from_end = from + n_left_from;
  u32 thread_index = vm->thread_index;
  vnet_interface_main_t *im = &vnm->interface_main;
  vnet_interface_per_thread_data_t *ptd =
    vec_elt_at_index (im->per_thread_data, thread_index);
  vlib_buffer_t *bufs[VLIB_FRAME_SIZE], **b = bufs;

  vlib_get_buffers (vm, from, b, n_left_from);

  while (n_left_from > 0)
    {
      u32 n_left_to_next;

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

      if (!do_segmentation)
	while (from + 8 <= from_end && n_left_to_next >= 4)
	  {
	    u32 bi0, bi1, bi2, bi3;
	    u32 next0, next1, next2, next3;
	    u32 swif0, swif1, swif2, swif3;
	    gso_trace_t *t0, *t1, *t2, *t3;
	    vnet_hw_interface_t *hi0, *hi1, *hi2, *hi3;

	    /* Prefetch next iteration. */
	    vlib_prefetch_buffer_header (b[4], LOAD);
	    vlib_prefetch_buffer_header (b[5], LOAD);
	    vlib_prefetch_buffer_header (b[6], LOAD);
	    vlib_prefetch_buffer_header (b[7], LOAD);

	    bi0 = from[0];
	    bi1 = from[1];
	    bi2 = from[2];
	    bi3 = from[3];
	    to_next[0] = bi0;
	    to_next[1] = bi1;
	    to_next[2] = bi2;
	    to_next[3] = bi3;

	    swif0 = vnet_buffer (b[0])->sw_if_index[VLIB_TX];
	    swif1 = vnet_buffer (b[1])->sw_if_index[VLIB_TX];
	    swif2 = vnet_buffer (b[2])->sw_if_index[VLIB_TX];
	    swif3 = vnet_buffer (b[3])->sw_if_index[VLIB_TX];

	    if (PREDICT_FALSE (hi->sw_if_index != swif0))
	      {
		hi0 = vnet_get_sup_hw_interface (vnm, swif0);
		if ((hi0->caps & VNET_HW_INTERFACE_CAP_SUPPORTS_TCP_GSO) ==
		      0 &&
		    (b[0]->flags & VNET_BUFFER_F_GSO))
		  break;
	      }
	    if (PREDICT_FALSE (hi->sw_if_index != swif1))
	      {
		hi1 = vnet_get_sup_hw_interface (vnm, swif1);
		if (!(hi1->caps & VNET_HW_INTERFACE_CAP_SUPPORTS_TCP_GSO) &&
		    (b[1]->flags & VNET_BUFFER_F_GSO))
		  break;
	      }
	    if (PREDICT_FALSE (hi->sw_if_index != swif2))
	      {
		hi2 = vnet_get_sup_hw_interface (vnm, swif2);
		if ((hi2->caps & VNET_HW_INTERFACE_CAP_SUPPORTS_TCP_GSO) ==
		      0 &&
		    (b[2]->flags & VNET_BUFFER_F_GSO))
		  break;
	      }
	    if (PREDICT_FALSE (hi->sw_if_index != swif3))
	      {
		hi3 = vnet_get_sup_hw_interface (vnm, swif3);
		if (!(hi3->caps & VNET_HW_INTERFACE_CAP_SUPPORTS_TCP_GSO) &&
		    (b[3]->flags & VNET_BUFFER_F_GSO))
		  break;
	      }

	    if (b[0]->flags & VLIB_BUFFER_IS_TRACED)
	      {
		t0 = vlib_add_trace (vm, node, b[0], sizeof (t0[0]));
		t0->flags = b[0]->flags & VNET_BUFFER_F_GSO;
		t0->gso_size = vnet_buffer2 (b[0])->gso_size;
		t0->gso_l4_hdr_sz = vnet_buffer2 (b[0])->gso_l4_hdr_sz;
		vnet_generic_header_offset_parser (b[0], &t0->gho, is_l2,
						   is_ip4, is_ip6);
	      }
	    if (b[1]->flags & VLIB_BUFFER_IS_TRACED)
	      {
		t1 = vlib_add_trace (vm, node, b[1], sizeof (t1[0]));
		t1->flags = b[1]->flags & VNET_BUFFER_F_GSO;
		t1->gso_size = vnet_buffer2 (b[1])->gso_size;
		t1->gso_l4_hdr_sz = vnet_buffer2 (b[1])->gso_l4_hdr_sz;
		vnet_generic_header_offset_parser (b[1], &t1->gho, is_l2,
						   is_ip4, is_ip6);
	      }
	    if (b[2]->flags & VLIB_BUFFER_IS_TRACED)
	      {
		t2 = vlib_add_trace (vm, node, b[2], sizeof (t2[0]));
		t2->flags = b[2]->flags & VNET_BUFFER_F_GSO;
		t2->gso_size = vnet_buffer2 (b[2])->gso_size;
		t2->gso_l4_hdr_sz = vnet_buffer2 (b[2])->gso_l4_hdr_sz;
		vnet_generic_header_offset_parser (b[2], &t2->gho, is_l2,
						   is_ip4, is_ip6);
	      }
	    if (b[3]->flags & VLIB_BUFFER_IS_TRACED)
	      {
		t3 = vlib_add_trace (vm, node, b[3], sizeof (t3[0]));
		t3->flags = b[3]->flags & VNET_BUFFER_F_GSO;
		t3->gso_size = vnet_buffer2 (b[3])->gso_size;
		t3->gso_l4_hdr_sz = vnet_buffer2 (b[3])->gso_l4_hdr_sz;
		vnet_generic_header_offset_parser (b[3], &t3->gho, is_l2,
						   is_ip4, is_ip6);
	      }

	    from += 4;
	    to_next += 4;
	    n_left_to_next -= 4;
	    n_left_from -= 4;

	    next0 = next1 = 0;
	    next2 = next3 = 0;
	    vnet_feature_next (&next0, b[0]);
	    vnet_feature_next (&next1, b[1]);
	    vnet_feature_next (&next2, b[2]);
	    vnet_feature_next (&next3, b[3]);
	    vlib_validate_buffer_enqueue_x4 (vm, node, next_index, to_next,
					     n_left_to_next, bi0, bi1, bi2,
					     bi3, next0, next1, next2, next3);
	    b += 4;
	  }

      while (from + 1 <= from_end && n_left_to_next > 0)
	{
	  u32 bi0, swif0;
	  gso_trace_t *t0;
	  vnet_hw_interface_t *hi0;
	  u32 next0 = 0;
	  u32 do_segmentation0 = 0;

	  swif0 = vnet_buffer (b[0])->sw_if_index[VLIB_TX];
	  if (PREDICT_FALSE (hi->sw_if_index != swif0))
	    {
	      hi0 = vnet_get_sup_hw_interface (vnm, swif0);
	      if ((hi0->caps & VNET_HW_INTERFACE_CAP_SUPPORTS_TCP_GSO) == 0 &&
		  (b[0]->flags & VNET_BUFFER_F_GSO))
		do_segmentation0 = 1;
	    }
	  else
	    do_segmentation0 = do_segmentation;

	  /* speculatively enqueue b0 to the current next frame */
	  to_next[0] = bi0 = from[0];
	  to_next += 1;
	  n_left_to_next -= 1;
	  from += 1;
	  n_left_from -= 1;

	  if (b[0]->flags & VLIB_BUFFER_IS_TRACED)
	    {
	      t0 = vlib_add_trace (vm, node, b[0], sizeof (t0[0]));
	      t0->flags = b[0]->flags & VNET_BUFFER_F_GSO;
	      t0->gso_size = vnet_buffer2 (b[0])->gso_size;
	      t0->gso_l4_hdr_sz = vnet_buffer2 (b[0])->gso_l4_hdr_sz;
	      vnet_generic_header_offset_parser (b[0], &t0->gho, is_l2,
						 is_ip4, is_ip6);
	    }

	  if (do_segmentation0)
	    {
	      if (PREDICT_FALSE (b[0]->flags & VNET_BUFFER_F_GSO))
		{
		  /*
		   * Undo the enqueue of the b0 - it is not going anywhere,
		   * and will be freed either after it's segmented or
		   * when dropped, if there is no buffers to segment into.
		   */
		  to_next -= 1;
		  n_left_to_next += 1;
		  /* undo the counting. */
		  generic_header_offset_t gho = { 0 };
		  u32 n_bytes_b0 = vlib_buffer_length_in_chain (vm, b[0]);
		  u32 n_tx_bytes = 0;
		  u32 inner_is_ip6 = is_ip6;

		  vnet_generic_header_offset_parser (b[0], &gho, is_l2,
						     is_ip4, is_ip6);

		  if (PREDICT_FALSE (gho.gho_flags & GHO_F_TUNNEL))
		    {
		      if (PREDICT_FALSE
			  (gho.gho_flags & (GHO_F_GRE_TUNNEL |
					    GHO_F_GENEVE_TUNNEL)))
			{
			  /* not supported yet */
			  drop_one_buffer_and_count (vm, vnm, node, from - 1,
						     hi->sw_if_index,
						     GSO_ERROR_UNHANDLED_TYPE);
			  b += 1;
			  continue;
			}

		      vnet_get_inner_header (b[0], &gho);

		      n_bytes_b0 -= gho.outer_hdr_sz;
		      inner_is_ip6 = (gho.gho_flags & GHO_F_IP6) != 0;
		    }

		  n_tx_bytes =
		    tso_segment_buffer (vm, ptd, bi0, b[0], &gho, n_bytes_b0,
					is_l2, inner_is_ip6);

		  if (PREDICT_FALSE (n_tx_bytes == 0))
		    {
		      drop_one_buffer_and_count (vm, vnm, node, from - 1,
						 hi->sw_if_index,
						 GSO_ERROR_NO_BUFFERS);
		      b += 1;
		      continue;
		    }


		  if (PREDICT_FALSE (gho.gho_flags & GHO_F_VXLAN_TUNNEL))
		    {
		      vnet_get_outer_header (b[0], &gho);
		      n_tx_bytes +=
			tso_segment_vxlan_tunnel_fixup (vm, ptd, b[0], &gho);
		    }
		  else
		    if (PREDICT_FALSE
			(gho.gho_flags & (GHO_F_IPIP_TUNNEL |
					  GHO_F_IPIP6_TUNNEL)))
		    {
		      vnet_get_outer_header (b[0], &gho);
		      n_tx_bytes +=
			tso_segment_ipip_tunnel_fixup (vm, ptd, b[0], &gho);
		    }

		  u16 n_tx_bufs = vec_len (ptd->split_buffers);
		  u32 *from_seg = ptd->split_buffers;

		  while (n_tx_bufs > 0)
		    {
		      u32 sbi0;
		      vlib_buffer_t *sb0;
		      while (n_tx_bufs > 0 && n_left_to_next > 0)
			{
			  sbi0 = to_next[0] = from_seg[0];
			  sb0 = vlib_get_buffer (vm, sbi0);
			  ASSERT (sb0->current_length > 0);
			  to_next += 1;
			  from_seg += 1;
			  n_left_to_next -= 1;
			  n_tx_bufs -= 1;
			  next0 = 0;
			  vnet_feature_next (&next0, sb0);
			  vlib_validate_buffer_enqueue_x1 (vm, node,
							   next_index,
							   to_next,
							   n_left_to_next,
							   sbi0, next0);
			}
		      vlib_put_next_frame (vm, node, next_index,
					   n_left_to_next);
		      if (n_tx_bufs > 0)
			vlib_get_next_frame (vm, node, next_index,
					     to_next, n_left_to_next);
		    }
		  /* The buffers were enqueued. Reset the length */
		  _vec_len (ptd->split_buffers) = 0;
		  /* Free the now segmented buffer */
		  vlib_buffer_free_one (vm, bi0);
		  b += 1;
		  continue;
		}
	    }

	  vnet_feature_next (&next0, b[0]);
	  vlib_validate_buffer_enqueue_x1 (vm, node, next_index, to_next,
					   n_left_to_next, bi0, next0);
	  b += 1;
	}
      vlib_put_next_frame (vm, node, next_index, n_left_to_next);
    }

  return frame->n_vectors;
}

static_always_inline uword
vnet_gso_inline (vlib_main_t * vm,
		 vlib_node_runtime_t * node, vlib_frame_t * frame, int is_l2,
		 int is_ip4, int is_ip6)
{
  vnet_main_t *vnm = vnet_get_main ();
  vnet_hw_interface_t *hi;

  if (frame->n_vectors > 0)
    {
      u32 *from = vlib_frame_vector_args (frame);
      vlib_buffer_t *b = vlib_get_buffer (vm, from[0]);
      hi = vnet_get_sup_hw_interface (vnm,
				      vnet_buffer (b)->sw_if_index[VLIB_TX]);

      if (hi->caps & (VNET_HW_INTERFACE_CAP_SUPPORTS_TCP_GSO |
		      VNET_HW_INTERFACE_CAP_SUPPORTS_VXLAN_TNL_GSO))
	return vnet_gso_node_inline (vm, node, frame, vnm, hi,
				     is_l2, is_ip4, is_ip6,
				     /* do_segmentation */ 0);
      else
	return vnet_gso_node_inline (vm, node, frame, vnm, hi,
				     is_l2, is_ip4, is_ip6,
				     /* do_segmentation */ 1);
    }
  return 0;
}

VLIB_NODE_FN (gso_l2_ip4_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
				vlib_frame_t * frame)
{
  return vnet_gso_inline (vm, node, frame, 1 /* l2 */ , 1 /* ip4 */ ,
			  0 /* ip6 */ );
}

VLIB_NODE_FN (gso_l2_ip6_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
				vlib_frame_t * frame)
{
  return vnet_gso_inline (vm, node, frame, 1 /* l2 */ , 0 /* ip4 */ ,
			  1 /* ip6 */ );
}

VLIB_NODE_FN (gso_ip4_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
			     vlib_frame_t * frame)
{
  return vnet_gso_inline (vm, node, frame, 0 /* l2 */ , 1 /* ip4 */ ,
			  0 /* ip6 */ );
}

VLIB_NODE_FN (gso_ip6_node) (vlib_main_t * vm, vlib_node_runtime_t * node,
			     vlib_frame_t * frame)
{
  return vnet_gso_inline (vm, node, frame, 0 /* l2 */ , 0 /* ip4 */ ,
			  1 /* ip6 */ );
}

/* *INDENT-OFF* */

VLIB_REGISTER_NODE (gso_l2_ip4_node) = {
  .vector_size = sizeof (u32),
  .format_trace = format_gso_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = ARRAY_LEN(gso_error_strings),
  .error_strings = gso_error_strings,
  .n_next_nodes = GSO_N_NEXT,
  .next_nodes = {
        [GSO_NEXT_DROP] = "error-drop",
  },
  .name = "gso-l2-ip4",
};

VLIB_REGISTER_NODE (gso_l2_ip6_node) = {
  .vector_size = sizeof (u32),
  .format_trace = format_gso_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = ARRAY_LEN(gso_error_strings),
  .error_strings = gso_error_strings,
  .n_next_nodes = GSO_N_NEXT,
  .next_nodes = {
        [GSO_NEXT_DROP] = "error-drop",
  },
  .name = "gso-l2-ip6",
};

VLIB_REGISTER_NODE (gso_ip4_node) = {
  .vector_size = sizeof (u32),
  .format_trace = format_gso_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = ARRAY_LEN(gso_error_strings),
  .error_strings = gso_error_strings,
  .n_next_nodes = GSO_N_NEXT,
  .next_nodes = {
        [GSO_NEXT_DROP] = "error-drop",
  },
  .name = "gso-ip4",
};

VLIB_REGISTER_NODE (gso_ip6_node) = {
  .vector_size = sizeof (u32),
  .format_trace = format_gso_trace,
  .type = VLIB_NODE_TYPE_INTERNAL,
  .n_errors = ARRAY_LEN(gso_error_strings),
  .error_strings = gso_error_strings,
  .n_next_nodes = GSO_N_NEXT,
  .next_nodes = {
        [GSO_NEXT_DROP] = "error-drop",
  },
  .name = "gso-ip6",
};

VNET_FEATURE_INIT (gso_l2_ip4_node, static) = {
  .arc_name = "l2-output-ip4",
  .node_name = "gso-l2-ip4",
  .runs_before = VNET_FEATURES ("l2-output-feat-arc-end"),
};

VNET_FEATURE_INIT (gso_l2_ip6_node, static) = {
  .arc_name = "l2-output-ip6",
  .node_name = "gso-l2-ip6",
  .runs_before = VNET_FEATURES ("l2-output-feat-arc-end"),
};

VNET_FEATURE_INIT (gso_ip4_node, static) = {
  .arc_name = "ip4-output",
  .node_name = "gso-ip4",
  .runs_before = VNET_FEATURES ("ipsec4-output-feature"),
};

VNET_FEATURE_INIT (gso_ip6_node, static) = {
  .arc_name = "ip6-output",
  .node_name = "gso-ip6",
  .runs_before = VNET_FEATURES ("ipsec6-output-feature"),
};

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