summaryrefslogtreecommitdiff
path: root/samples/bpf/xsk_fwd.c
blob: 2324e18ccc7e8eae2058224929eb9db63b8a0397 (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
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
// SPDX-License-Identifier: GPL-2.0
/* Copyright(c) 2020 Intel Corporation. */

#define _GNU_SOURCE
#include <poll.h>
#include <pthread.h>
#include <signal.h>
#include <sched.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>
#include <getopt.h>
#include <netinet/ether.h>
#include <net/if.h>

#include <linux/bpf.h>
#include <linux/if_link.h>
#include <linux/if_xdp.h>

#include <bpf/libbpf.h>
#include <bpf/xsk.h>
#include <bpf/bpf.h>

/* libbpf APIs for AF_XDP are deprecated starting from v0.7 */
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"

#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))

typedef __u64 u64;
typedef __u32 u32;
typedef __u16 u16;
typedef __u8  u8;

/* This program illustrates the packet forwarding between multiple AF_XDP
 * sockets in multi-threaded environment. All threads are sharing a common
 * buffer pool, with each socket having its own private buffer cache.
 *
 * Example 1: Single thread handling two sockets. The packets received by socket
 * A (interface IFA, queue QA) are forwarded to socket B (interface IFB, queue
 * QB), while the packets received by socket B are forwarded to socket A. The
 * thread is running on CPU core X:
 *
 *         ./xsk_fwd -i IFA -q QA -i IFB -q QB -c X
 *
 * Example 2: Two threads, each handling two sockets. The thread running on CPU
 * core X forwards all the packets received by socket A to socket B, and all the
 * packets received by socket B to socket A. The thread running on CPU core Y is
 * performing the same packet forwarding between sockets C and D:
 *
 *         ./xsk_fwd -i IFA -q QA -i IFB -q QB -i IFC -q QC -i IFD -q QD
 *         -c CX -c CY
 */

/*
 * Buffer pool and buffer cache
 *
 * For packet forwarding, the packet buffers are typically allocated from the
 * pool for packet reception and freed back to the pool for further reuse once
 * the packet transmission is completed.
 *
 * The buffer pool is shared between multiple threads. In order to minimize the
 * access latency to the shared buffer pool, each thread creates one (or
 * several) buffer caches, which, unlike the buffer pool, are private to the
 * thread that creates them and therefore cannot be shared with other threads.
 * The access to the shared pool is only needed either (A) when the cache gets
 * empty due to repeated buffer allocations and it needs to be replenished from
 * the pool, or (B) when the cache gets full due to repeated buffer free and it
 * needs to be flushed back to the pull.
 *
 * In a packet forwarding system, a packet received on any input port can
 * potentially be transmitted on any output port, depending on the forwarding
 * configuration. For AF_XDP sockets, for this to work with zero-copy of the
 * packet buffers when, it is required that the buffer pool memory fits into the
 * UMEM area shared by all the sockets.
 */

struct bpool_params {
	u32 n_buffers;
	u32 buffer_size;
	int mmap_flags;

	u32 n_users_max;
	u32 n_buffers_per_slab;
};

/* This buffer pool implementation organizes the buffers into equally sized
 * slabs of *n_buffers_per_slab*. Initially, there are *n_slabs* slabs in the
 * pool that are completely filled with buffer pointers (full slabs).
 *
 * Each buffer cache has a slab for buffer allocation and a slab for buffer
 * free, with both of these slabs initially empty. When the cache's allocation
 * slab goes empty, it is swapped with one of the available full slabs from the
 * pool, if any is available. When the cache's free slab goes full, it is
 * swapped for one of the empty slabs from the pool, which is guaranteed to
 * succeed.
 *
 * Partially filled slabs never get traded between the cache and the pool
 * (except when the cache itself is destroyed), which enables fast operation
 * through pointer swapping.
 */
struct bpool {
	struct bpool_params params;
	pthread_mutex_t lock;
	void *addr;

	u64 **slabs;
	u64 **slabs_reserved;
	u64 *buffers;
	u64 *buffers_reserved;

	u64 n_slabs;
	u64 n_slabs_reserved;
	u64 n_buffers;

	u64 n_slabs_available;
	u64 n_slabs_reserved_available;

	struct xsk_umem_config umem_cfg;
	struct xsk_ring_prod umem_fq;
	struct xsk_ring_cons umem_cq;
	struct xsk_umem *umem;
};

static struct bpool *
bpool_init(struct bpool_params *params,
	   struct xsk_umem_config *umem_cfg)
{
	u64 n_slabs, n_slabs_reserved, n_buffers, n_buffers_reserved;
	u64 slabs_size, slabs_reserved_size;
	u64 buffers_size, buffers_reserved_size;
	u64 total_size, i;
	struct bpool *bp;
	u8 *p;
	int status;

	/* Use libbpf 1.0 API mode */
	libbpf_set_strict_mode(LIBBPF_STRICT_ALL);

	/* bpool internals dimensioning. */
	n_slabs = (params->n_buffers + params->n_buffers_per_slab - 1) /
		params->n_buffers_per_slab;
	n_slabs_reserved = params->n_users_max * 2;
	n_buffers = n_slabs * params->n_buffers_per_slab;
	n_buffers_reserved = n_slabs_reserved * params->n_buffers_per_slab;

	slabs_size = n_slabs * sizeof(u64 *);
	slabs_reserved_size = n_slabs_reserved * sizeof(u64 *);
	buffers_size = n_buffers * sizeof(u64);
	buffers_reserved_size = n_buffers_reserved * sizeof(u64);

	total_size = sizeof(struct bpool) +
		slabs_size + slabs_reserved_size +
		buffers_size + buffers_reserved_size;

	/* bpool memory allocation. */
	p = calloc(total_size, sizeof(u8));
	if (!p)
		return NULL;

	/* bpool memory initialization. */
	bp = (struct bpool *)p;
	memcpy(&bp->params, params, sizeof(*params));
	bp->params.n_buffers = n_buffers;

	bp->slabs = (u64 **)&p[sizeof(struct bpool)];
	bp->slabs_reserved = (u64 **)&p[sizeof(struct bpool) +
		slabs_size];
	bp->buffers = (u64 *)&p[sizeof(struct bpool) +
		slabs_size + slabs_reserved_size];
	bp->buffers_reserved = (u64 *)&p[sizeof(struct bpool) +
		slabs_size + slabs_reserved_size + buffers_size];

	bp->n_slabs = n_slabs;
	bp->n_slabs_reserved = n_slabs_reserved;
	bp->n_buffers = n_buffers;

	for (i = 0; i < n_slabs; i++)
		bp->slabs[i] = &bp->buffers[i * params->n_buffers_per_slab];
	bp->n_slabs_available = n_slabs;

	for (i = 0; i < n_slabs_reserved; i++)
		bp->slabs_reserved[i] = &bp->buffers_reserved[i *
			params->n_buffers_per_slab];
	bp->n_slabs_reserved_available = n_slabs_reserved;

	for (i = 0; i < n_buffers; i++)
		bp->buffers[i] = i * params->buffer_size;

	/* lock. */
	status = pthread_mutex_init(&bp->lock, NULL);
	if (status) {
		free(p);
		return NULL;
	}

	/* mmap. */
	bp->addr = mmap(NULL,
			n_buffers * params->buffer_size,
			PROT_READ | PROT_WRITE,
			MAP_PRIVATE | MAP_ANONYMOUS | params->mmap_flags,
			-1,
			0);
	if (bp->addr == MAP_FAILED) {
		pthread_mutex_destroy(&bp->lock);
		free(p);
		return NULL;
	}

	/* umem. */
	status = xsk_umem__create(&bp->umem,
				  bp->addr,
				  bp->params.n_buffers * bp->params.buffer_size,
				  &bp->umem_fq,
				  &bp->umem_cq,
				  umem_cfg);
	if (status) {
		munmap(bp->addr, bp->params.n_buffers * bp->params.buffer_size);
		pthread_mutex_destroy(&bp->lock);
		free(p);
		return NULL;
	}
	memcpy(&bp->umem_cfg, umem_cfg, sizeof(*umem_cfg));

	return bp;
}

static void
bpool_free(struct bpool *bp)
{
	if (!bp)
		return;

	xsk_umem__delete(bp->umem);
	munmap(bp->addr, bp->params.n_buffers * bp->params.buffer_size);
	pthread_mutex_destroy(&bp->lock);
	free(bp);
}

struct bcache {
	struct bpool *bp;

	u64 *slab_cons;
	u64 *slab_prod;

	u64 n_buffers_cons;
	u64 n_buffers_prod;
};

static u32
bcache_slab_size(struct bcache *bc)
{
	struct bpool *bp = bc->bp;

	return bp->params.n_buffers_per_slab;
}

static struct bcache *
bcache_init(struct bpool *bp)
{
	struct bcache *bc;

	bc = calloc(1, sizeof(struct bcache));
	if (!bc)
		return NULL;

	bc->bp = bp;
	bc->n_buffers_cons = 0;
	bc->n_buffers_prod = 0;

	pthread_mutex_lock(&bp->lock);
	if (bp->n_slabs_reserved_available == 0) {
		pthread_mutex_unlock(&bp->lock);
		free(bc);
		return NULL;
	}

	bc->slab_cons = bp->slabs_reserved[bp->n_slabs_reserved_available - 1];
	bc->slab_prod = bp->slabs_reserved[bp->n_slabs_reserved_available - 2];
	bp->n_slabs_reserved_available -= 2;
	pthread_mutex_unlock(&bp->lock);

	return bc;
}

static void
bcache_free(struct bcache *bc)
{
	struct bpool *bp;

	if (!bc)
		return;

	/* In order to keep this example simple, the case of freeing any
	 * existing buffers from the cache back to the pool is ignored.
	 */

	bp = bc->bp;
	pthread_mutex_lock(&bp->lock);
	bp->slabs_reserved[bp->n_slabs_reserved_available] = bc->slab_prod;
	bp->slabs_reserved[bp->n_slabs_reserved_available + 1] = bc->slab_cons;
	bp->n_slabs_reserved_available += 2;
	pthread_mutex_unlock(&bp->lock);

	free(bc);
}

/* To work correctly, the implementation requires that the *n_buffers* input
 * argument is never greater than the buffer pool's *n_buffers_per_slab*. This
 * is typically the case, with one exception taking place when large number of
 * buffers are allocated at init time (e.g. for the UMEM fill queue setup).
 */
static inline u32
bcache_cons_check(struct bcache *bc, u32 n_buffers)
{
	struct bpool *bp = bc->bp;
	u64 n_buffers_per_slab = bp->params.n_buffers_per_slab;
	u64 n_buffers_cons = bc->n_buffers_cons;
	u64 n_slabs_available;
	u64 *slab_full;

	/*
	 * Consumer slab is not empty: Use what's available locally. Do not
	 * look for more buffers from the pool when the ask can only be
	 * partially satisfied.
	 */
	if (n_buffers_cons)
		return (n_buffers_cons < n_buffers) ?
			n_buffers_cons :
			n_buffers;

	/*
	 * Consumer slab is empty: look to trade the current consumer slab
	 * (full) for a full slab from the pool, if any is available.
	 */
	pthread_mutex_lock(&bp->lock);
	n_slabs_available = bp->n_slabs_available;
	if (!n_slabs_available) {
		pthread_mutex_unlock(&bp->lock);
		return 0;
	}

	n_slabs_available--;
	slab_full = bp->slabs[n_slabs_available];
	bp->slabs[n_slabs_available] = bc->slab_cons;
	bp->n_slabs_available = n_slabs_available;
	pthread_mutex_unlock(&bp->lock);

	bc->slab_cons = slab_full;
	bc->n_buffers_cons = n_buffers_per_slab;
	return n_buffers;
}

static inline u64
bcache_cons(struct bcache *bc)
{
	u64 n_buffers_cons = bc->n_buffers_cons - 1;
	u64 buffer;

	buffer = bc->slab_cons[n_buffers_cons];
	bc->n_buffers_cons = n_buffers_cons;
	return buffer;
}

static inline void
bcache_prod(struct bcache *bc, u64 buffer)
{
	struct bpool *bp = bc->bp;
	u64 n_buffers_per_slab = bp->params.n_buffers_per_slab;
	u64 n_buffers_prod = bc->n_buffers_prod;
	u64 n_slabs_available;
	u64 *slab_empty;

	/*
	 * Producer slab is not yet full: store the current buffer to it.
	 */
	if (n_buffers_prod < n_buffers_per_slab) {
		bc->slab_prod[n_buffers_prod] = buffer;
		bc->n_buffers_prod = n_buffers_prod + 1;
		return;
	}

	/*
	 * Producer slab is full: trade the cache's current producer slab
	 * (full) for an empty slab from the pool, then store the current
	 * buffer to the new producer slab. As one full slab exists in the
	 * cache, it is guaranteed that there is at least one empty slab
	 * available in the pool.
	 */
	pthread_mutex_lock(&bp->lock);
	n_slabs_available = bp->n_slabs_available;
	slab_empty = bp->slabs[n_slabs_available];
	bp->slabs[n_slabs_available] = bc->slab_prod;
	bp->n_slabs_available = n_slabs_available + 1;
	pthread_mutex_unlock(&bp->lock);

	slab_empty[0] = buffer;
	bc->slab_prod = slab_empty;
	bc->n_buffers_prod = 1;
}

/*
 * Port
 *
 * Each of the forwarding ports sits on top of an AF_XDP socket. In order for
 * packet forwarding to happen with no packet buffer copy, all the sockets need
 * to share the same UMEM area, which is used as the buffer pool memory.
 */
#ifndef MAX_BURST_RX
#define MAX_BURST_RX 64
#endif

#ifndef MAX_BURST_TX
#define MAX_BURST_TX 64
#endif

struct burst_rx {
	u64 addr[MAX_BURST_RX];
	u32 len[MAX_BURST_RX];
};

struct burst_tx {
	u64 addr[MAX_BURST_TX];
	u32 len[MAX_BURST_TX];
	u32 n_pkts;
};

struct port_params {
	struct xsk_socket_config xsk_cfg;
	struct bpool *bp;
	const char *iface;
	u32 iface_queue;
};

struct port {
	struct port_params params;

	struct bcache *bc;

	struct xsk_ring_cons rxq;
	struct xsk_ring_prod txq;
	struct xsk_ring_prod umem_fq;
	struct xsk_ring_cons umem_cq;
	struct xsk_socket *xsk;
	int umem_fq_initialized;

	u64 n_pkts_rx;
	u64 n_pkts_tx;
};

static void
port_free(struct port *p)
{
	if (!p)
		return;

	/* To keep this example simple, the code to free the buffers from the
	 * socket's receive and transmit queues, as well as from the UMEM fill
	 * and completion queues, is not included.
	 */

	if (p->xsk)
		xsk_socket__delete(p->xsk);

	bcache_free(p->bc);

	free(p);
}

static struct port *
port_init(struct port_params *params)
{
	struct port *p;
	u32 umem_fq_size, pos = 0;
	int status, i;

	/* Memory allocation and initialization. */
	p = calloc(sizeof(struct port), 1);
	if (!p)
		return NULL;

	memcpy(&p->params, params, sizeof(p->params));
	umem_fq_size = params->bp->umem_cfg.fill_size;

	/* bcache. */
	p->bc = bcache_init(params->bp);
	if (!p->bc ||
	    (bcache_slab_size(p->bc) < umem_fq_size) ||
	    (bcache_cons_check(p->bc, umem_fq_size) < umem_fq_size)) {
		port_free(p);
		return NULL;
	}

	/* xsk socket. */
	status = xsk_socket__create_shared(&p->xsk,
					   params->iface,
					   params->iface_queue,
					   params->bp->umem,
					   &p->rxq,
					   &p->txq,
					   &p->umem_fq,
					   &p->umem_cq,
					   &params->xsk_cfg);
	if (status) {
		port_free(p);
		return NULL;
	}

	/* umem fq. */
	xsk_ring_prod__reserve(&p->umem_fq, umem_fq_size, &pos);

	for (i = 0; i < umem_fq_size; i++)
		*xsk_ring_prod__fill_addr(&p->umem_fq, pos + i) =
			bcache_cons(p->bc);

	xsk_ring_prod__submit(&p->umem_fq, umem_fq_size);
	p->umem_fq_initialized = 1;

	return p;
}

static inline u32
port_rx_burst(struct port *p, struct burst_rx *b)
{
	u32 n_pkts, pos, i;

	/* Free buffers for FQ replenish. */
	n_pkts = ARRAY_SIZE(b->addr);

	n_pkts = bcache_cons_check(p->bc, n_pkts);
	if (!n_pkts)
		return 0;

	/* RXQ. */
	n_pkts = xsk_ring_cons__peek(&p->rxq, n_pkts, &pos);
	if (!n_pkts) {
		if (xsk_ring_prod__needs_wakeup(&p->umem_fq)) {
			struct pollfd pollfd = {
				.fd = xsk_socket__fd(p->xsk),
				.events = POLLIN,
			};

			poll(&pollfd, 1, 0);
		}
		return 0;
	}

	for (i = 0; i < n_pkts; i++) {
		b->addr[i] = xsk_ring_cons__rx_desc(&p->rxq, pos + i)->addr;
		b->len[i] = xsk_ring_cons__rx_desc(&p->rxq, pos + i)->len;
	}

	xsk_ring_cons__release(&p->rxq, n_pkts);
	p->n_pkts_rx += n_pkts;

	/* UMEM FQ. */
	for ( ; ; ) {
		int status;

		status = xsk_ring_prod__reserve(&p->umem_fq, n_pkts, &pos);
		if (status == n_pkts)
			break;

		if (xsk_ring_prod__needs_wakeup(&p->umem_fq)) {
			struct pollfd pollfd = {
				.fd = xsk_socket__fd(p->xsk),
				.events = POLLIN,
			};

			poll(&pollfd, 1, 0);
		}
	}

	for (i = 0; i < n_pkts; i++)
		*xsk_ring_prod__fill_addr(&p->umem_fq, pos + i) =
			bcache_cons(p->bc);

	xsk_ring_prod__submit(&p->umem_fq, n_pkts);

	return n_pkts;
}

static inline void
port_tx_burst(struct port *p, struct burst_tx *b)
{
	u32 n_pkts, pos, i;
	int status;

	/* UMEM CQ. */
	n_pkts = p->params.bp->umem_cfg.comp_size;

	n_pkts = xsk_ring_cons__peek(&p->umem_cq, n_pkts, &pos);

	for (i = 0; i < n_pkts; i++) {
		u64 addr = *xsk_ring_cons__comp_addr(&p->umem_cq, pos + i);

		bcache_prod(p->bc, addr);
	}

	xsk_ring_cons__release(&p->umem_cq, n_pkts);

	/* TXQ. */
	n_pkts = b->n_pkts;

	for ( ; ; ) {
		status = xsk_ring_prod__reserve(&p->txq, n_pkts, &pos);
		if (status == n_pkts)
			break;

		if (xsk_ring_prod__needs_wakeup(&p->txq))
			sendto(xsk_socket__fd(p->xsk), NULL, 0, MSG_DONTWAIT,
			       NULL, 0);
	}

	for (i = 0; i < n_pkts; i++) {
		xsk_ring_prod__tx_desc(&p->txq, pos + i)->addr = b->addr[i];
		xsk_ring_prod__tx_desc(&p->txq, pos + i)->len = b->len[i];
	}

	xsk_ring_prod__submit(&p->txq, n_pkts);
	if (xsk_ring_prod__needs_wakeup(&p->txq))
		sendto(xsk_socket__fd(p->xsk), NULL, 0, MSG_DONTWAIT, NULL, 0);
	p->n_pkts_tx += n_pkts;
}

/*
 * Thread
 *
 * Packet forwarding threads.
 */
#ifndef MAX_PORTS_PER_THREAD
#define MAX_PORTS_PER_THREAD 16
#endif

struct thread_data {
	struct port *ports_rx[MAX_PORTS_PER_THREAD];
	struct port *ports_tx[MAX_PORTS_PER_THREAD];
	u32 n_ports_rx;
	struct burst_rx burst_rx;
	struct burst_tx burst_tx[MAX_PORTS_PER_THREAD];
	u32 cpu_core_id;
	int quit;
};

static void swap_mac_addresses(void *data)
{
	struct ether_header *eth = (struct ether_header *)data;
	struct ether_addr *src_addr = (struct ether_addr *)&eth->ether_shost;
	struct ether_addr *dst_addr = (struct ether_addr *)&eth->ether_dhost;
	struct ether_addr tmp;

	tmp = *src_addr;
	*src_addr = *dst_addr;
	*dst_addr = tmp;
}

static void *
thread_func(void *arg)
{
	struct thread_data *t = arg;
	cpu_set_t cpu_cores;
	u32 i;

	CPU_ZERO(&cpu_cores);
	CPU_SET(t->cpu_core_id, &cpu_cores);
	pthread_setaffinity_np(pthread_self(), sizeof(cpu_set_t), &cpu_cores);

	for (i = 0; !t->quit; i = (i + 1) & (t->n_ports_rx - 1)) {
		struct port *port_rx = t->ports_rx[i];
		struct port *port_tx = t->ports_tx[i];
		struct burst_rx *brx = &t->burst_rx;
		struct burst_tx *btx = &t->burst_tx[i];
		u32 n_pkts, j;

		/* RX. */
		n_pkts = port_rx_burst(port_rx, brx);
		if (!n_pkts)
			continue;

		/* Process & TX. */
		for (j = 0; j < n_pkts; j++) {
			u64 addr = xsk_umem__add_offset_to_addr(brx->addr[j]);
			u8 *pkt = xsk_umem__get_data(port_rx->params.bp->addr,
						     addr);

			swap_mac_addresses(pkt);

			btx->addr[btx->n_pkts] = brx->addr[j];
			btx->len[btx->n_pkts] = brx->len[j];
			btx->n_pkts++;

			if (btx->n_pkts == MAX_BURST_TX) {
				port_tx_burst(port_tx, btx);
				btx->n_pkts = 0;
			}
		}
	}

	return NULL;
}

/*
 * Process
 */
static const struct bpool_params bpool_params_default = {
	.n_buffers = 64 * 1024,
	.buffer_size = XSK_UMEM__DEFAULT_FRAME_SIZE,
	.mmap_flags = 0,

	.n_users_max = 16,
	.n_buffers_per_slab = XSK_RING_PROD__DEFAULT_NUM_DESCS * 2,
};

static const struct xsk_umem_config umem_cfg_default = {
	.fill_size = XSK_RING_PROD__DEFAULT_NUM_DESCS * 2,
	.comp_size = XSK_RING_CONS__DEFAULT_NUM_DESCS,
	.frame_size = XSK_UMEM__DEFAULT_FRAME_SIZE,
	.frame_headroom = XSK_UMEM__DEFAULT_FRAME_HEADROOM,
	.flags = 0,
};

static const struct port_params port_params_default = {
	.xsk_cfg = {
		.rx_size = XSK_RING_CONS__DEFAULT_NUM_DESCS,
		.tx_size = XSK_RING_PROD__DEFAULT_NUM_DESCS,
		.libbpf_flags = 0,
		.xdp_flags = XDP_FLAGS_DRV_MODE,
		.bind_flags = XDP_USE_NEED_WAKEUP | XDP_ZEROCOPY,
	},

	.bp = NULL,
	.iface = NULL,
	.iface_queue = 0,
};

#ifndef MAX_PORTS
#define MAX_PORTS 64
#endif

#ifndef MAX_THREADS
#define MAX_THREADS 64
#endif

static struct bpool_params bpool_params;
static struct xsk_umem_config umem_cfg;
static struct bpool *bp;

static struct port_params port_params[MAX_PORTS];
static struct port *ports[MAX_PORTS];
static u64 n_pkts_rx[MAX_PORTS];
static u64 n_pkts_tx[MAX_PORTS];
static int n_ports;

static pthread_t threads[MAX_THREADS];
static struct thread_data thread_data[MAX_THREADS];
static int n_threads;

static void
print_usage(char *prog_name)
{
	const char *usage =
		"Usage:\n"
		"\t%s [ -b SIZE ] -c CORE -i INTERFACE [ -q QUEUE ]\n"
		"\n"
		"-c CORE        CPU core to run a packet forwarding thread\n"
		"               on. May be invoked multiple times.\n"
		"\n"
		"-b SIZE        Number of buffers in the buffer pool shared\n"
		"               by all the forwarding threads. Default: %u.\n"
		"\n"
		"-i INTERFACE   Network interface. Each (INTERFACE, QUEUE)\n"
		"               pair specifies one forwarding port. May be\n"
		"               invoked multiple times.\n"
		"\n"
		"-q QUEUE       Network interface queue for RX and TX. Each\n"
		"               (INTERFACE, QUEUE) pair specified one\n"
		"               forwarding port. Default: %u. May be invoked\n"
		"               multiple times.\n"
		"\n";
	printf(usage,
	       prog_name,
	       bpool_params_default.n_buffers,
	       port_params_default.iface_queue);
}

static int
parse_args(int argc, char **argv)
{
	struct option lgopts[] = {
		{ NULL,  0, 0, 0 }
	};
	int opt, option_index;

	/* Parse the input arguments. */
	for ( ; ;) {
		opt = getopt_long(argc, argv, "c:i:q:", lgopts, &option_index);
		if (opt == EOF)
			break;

		switch (opt) {
		case 'b':
			bpool_params.n_buffers = atoi(optarg);
			break;

		case 'c':
			if (n_threads == MAX_THREADS) {
				printf("Max number of threads (%d) reached.\n",
				       MAX_THREADS);
				return -1;
			}

			thread_data[n_threads].cpu_core_id = atoi(optarg);
			n_threads++;
			break;

		case 'i':
			if (n_ports == MAX_PORTS) {
				printf("Max number of ports (%d) reached.\n",
				       MAX_PORTS);
				return -1;
			}

			port_params[n_ports].iface = optarg;
			port_params[n_ports].iface_queue = 0;
			n_ports++;
			break;

		case 'q':
			if (n_ports == 0) {
				printf("No port specified for queue.\n");
				return -1;
			}
			port_params[n_ports - 1].iface_queue = atoi(optarg);
			break;

		default:
			printf("Illegal argument.\n");
			return -1;
		}
	}

	optind = 1; /* reset getopt lib */

	/* Check the input arguments. */
	if (!n_ports) {
		printf("No ports specified.\n");
		return -1;
	}

	if (!n_threads) {
		printf("No threads specified.\n");
		return -1;
	}

	if (n_ports % n_threads) {
		printf("Ports cannot be evenly distributed to threads.\n");
		return -1;
	}

	return 0;
}

static void
print_port(u32 port_id)
{
	struct port *port = ports[port_id];

	printf("Port %u: interface = %s, queue = %u\n",
	       port_id, port->params.iface, port->params.iface_queue);
}

static void
print_thread(u32 thread_id)
{
	struct thread_data *t = &thread_data[thread_id];
	u32 i;

	printf("Thread %u (CPU core %u): ",
	       thread_id, t->cpu_core_id);

	for (i = 0; i < t->n_ports_rx; i++) {
		struct port *port_rx = t->ports_rx[i];
		struct port *port_tx = t->ports_tx[i];

		printf("(%s, %u) -> (%s, %u), ",
		       port_rx->params.iface,
		       port_rx->params.iface_queue,
		       port_tx->params.iface,
		       port_tx->params.iface_queue);
	}

	printf("\n");
}

static void
print_port_stats_separator(void)
{
	printf("+-%4s-+-%12s-+-%13s-+-%12s-+-%13s-+\n",
	       "----",
	       "------------",
	       "-------------",
	       "------------",
	       "-------------");
}

static void
print_port_stats_header(void)
{
	print_port_stats_separator();
	printf("| %4s | %12s | %13s | %12s | %13s |\n",
	       "Port",
	       "RX packets",
	       "RX rate (pps)",
	       "TX packets",
	       "TX_rate (pps)");
	print_port_stats_separator();
}

static void
print_port_stats_trailer(void)
{
	print_port_stats_separator();
	printf("\n");
}

static void
print_port_stats(int port_id, u64 ns_diff)
{
	struct port *p = ports[port_id];
	double rx_pps, tx_pps;

	rx_pps = (p->n_pkts_rx - n_pkts_rx[port_id]) * 1000000000. / ns_diff;
	tx_pps = (p->n_pkts_tx - n_pkts_tx[port_id]) * 1000000000. / ns_diff;

	printf("| %4d | %12llu | %13.0f | %12llu | %13.0f |\n",
	       port_id,
	       p->n_pkts_rx,
	       rx_pps,
	       p->n_pkts_tx,
	       tx_pps);

	n_pkts_rx[port_id] = p->n_pkts_rx;
	n_pkts_tx[port_id] = p->n_pkts_tx;
}

static void
print_port_stats_all(u64 ns_diff)
{
	int i;

	print_port_stats_header();
	for (i = 0; i < n_ports; i++)
		print_port_stats(i, ns_diff);
	print_port_stats_trailer();
}

static int quit;

static void
signal_handler(int sig)
{
	quit = 1;
}

static void remove_xdp_program(void)
{
	int i;

	for (i = 0 ; i < n_ports; i++)
		bpf_xdp_detach(if_nametoindex(port_params[i].iface),
			       port_params[i].xsk_cfg.xdp_flags, NULL);
}

int main(int argc, char **argv)
{
	struct timespec time;
	u64 ns0;
	int i;

	/* Parse args. */
	memcpy(&bpool_params, &bpool_params_default,
	       sizeof(struct bpool_params));
	memcpy(&umem_cfg, &umem_cfg_default,
	       sizeof(struct xsk_umem_config));
	for (i = 0; i < MAX_PORTS; i++)
		memcpy(&port_params[i], &port_params_default,
		       sizeof(struct port_params));

	if (parse_args(argc, argv)) {
		print_usage(argv[0]);
		return -1;
	}

	/* Buffer pool initialization. */
	bp = bpool_init(&bpool_params, &umem_cfg);
	if (!bp) {
		printf("Buffer pool initialization failed.\n");
		return -1;
	}
	printf("Buffer pool created successfully.\n");

	/* Ports initialization. */
	for (i = 0; i < MAX_PORTS; i++)
		port_params[i].bp = bp;

	for (i = 0; i < n_ports; i++) {
		ports[i] = port_init(&port_params[i]);
		if (!ports[i]) {
			printf("Port %d initialization failed.\n", i);
			return -1;
		}
		print_port(i);
	}
	printf("All ports created successfully.\n");

	/* Threads. */
	for (i = 0; i < n_threads; i++) {
		struct thread_data *t = &thread_data[i];
		u32 n_ports_per_thread = n_ports / n_threads, j;

		for (j = 0; j < n_ports_per_thread; j++) {
			t->ports_rx[j] = ports[i * n_ports_per_thread + j];
			t->ports_tx[j] = ports[i * n_ports_per_thread +
				(j + 1) % n_ports_per_thread];
		}

		t->n_ports_rx = n_ports_per_thread;

		print_thread(i);
	}

	for (i = 0; i < n_threads; i++) {
		int status;

		status = pthread_create(&threads[i],
					NULL,
					thread_func,
					&thread_data[i]);
		if (status) {
			printf("Thread %d creation failed.\n", i);
			return -1;
		}
	}
	printf("All threads created successfully.\n");

	/* Print statistics. */
	signal(SIGINT, signal_handler);
	signal(SIGTERM, signal_handler);
	signal(SIGABRT, signal_handler);

	clock_gettime(CLOCK_MONOTONIC, &time);
	ns0 = time.tv_sec * 1000000000UL + time.tv_nsec;
	for ( ; !quit; ) {
		u64 ns1, ns_diff;

		sleep(1);
		clock_gettime(CLOCK_MONOTONIC, &time);
		ns1 = time.tv_sec * 1000000000UL + time.tv_nsec;
		ns_diff = ns1 - ns0;
		ns0 = ns1;

		print_port_stats_all(ns_diff);
	}

	/* Threads completion. */
	printf("Quit.\n");
	for (i = 0; i < n_threads; i++)
		thread_data[i].quit = 1;

	for (i = 0; i < n_threads; i++)
		pthread_join(threads[i], NULL);

	for (i = 0; i < n_ports; i++)
		port_free(ports[i]);

	bpool_free(bp);

	remove_xdp_program();

	return 0;
}