summaryrefslogtreecommitdiffstats
path: root/tools/testing/selftests/bpf/xsk.c
blob: 0b3ff49c740d455c5101f15d3ec2ea25e3096bae (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
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)

/*
 * AF_XDP user-space access library.
 *
 * Copyright(c) 2018 - 2019 Intel Corporation.
 *
 * Author(s): Magnus Karlsson <magnus.karlsson@intel.com>
 */

#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <asm/barrier.h>
#include <linux/compiler.h>
#include <linux/ethtool.h>
#include <linux/filter.h>
#include <linux/if_ether.h>
#include <linux/if_packet.h>
#include <linux/if_xdp.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/sockios.h>
#include <net/if.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <linux/if_link.h>

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

#ifndef SOL_XDP
 #define SOL_XDP 283
#endif

#ifndef AF_XDP
 #define AF_XDP 44
#endif

#ifndef PF_XDP
 #define PF_XDP AF_XDP
#endif

#define pr_warn(fmt, ...) fprintf(stderr, fmt, ##__VA_ARGS__)

enum xsk_prog {
	XSK_PROG_FALLBACK,
	XSK_PROG_REDIRECT_FLAGS,
};

struct xsk_umem {
	struct xsk_ring_prod *fill_save;
	struct xsk_ring_cons *comp_save;
	char *umem_area;
	struct xsk_umem_config config;
	int fd;
	int refcount;
	struct list_head ctx_list;
	bool rx_ring_setup_done;
	bool tx_ring_setup_done;
};

struct xsk_ctx {
	struct xsk_ring_prod *fill;
	struct xsk_ring_cons *comp;
	__u32 queue_id;
	struct xsk_umem *umem;
	int refcount;
	int ifindex;
	struct list_head list;
	int prog_fd;
	int link_fd;
	int xsks_map_fd;
	char ifname[IFNAMSIZ];
	bool has_bpf_link;
};

struct xsk_socket {
	struct xsk_ring_cons *rx;
	struct xsk_ring_prod *tx;
	__u64 outstanding_tx;
	struct xsk_ctx *ctx;
	struct xsk_socket_config config;
	int fd;
};

struct xsk_nl_info {
	bool xdp_prog_attached;
	int ifindex;
	int fd;
};

/* Up until and including Linux 5.3 */
struct xdp_ring_offset_v1 {
	__u64 producer;
	__u64 consumer;
	__u64 desc;
};

/* Up until and including Linux 5.3 */
struct xdp_mmap_offsets_v1 {
	struct xdp_ring_offset_v1 rx;
	struct xdp_ring_offset_v1 tx;
	struct xdp_ring_offset_v1 fr;
	struct xdp_ring_offset_v1 cr;
};

int xsk_umem__fd(const struct xsk_umem *umem)
{
	return umem ? umem->fd : -EINVAL;
}

int xsk_socket__fd(const struct xsk_socket *xsk)
{
	return xsk ? xsk->fd : -EINVAL;
}

static bool xsk_page_aligned(void *buffer)
{
	unsigned long addr = (unsigned long)buffer;

	return !(addr & (getpagesize() - 1));
}

static void xsk_set_umem_config(struct xsk_umem_config *cfg,
				const struct xsk_umem_config *usr_cfg)
{
	if (!usr_cfg) {
		cfg->fill_size = XSK_RING_PROD__DEFAULT_NUM_DESCS;
		cfg->comp_size = XSK_RING_CONS__DEFAULT_NUM_DESCS;
		cfg->frame_size = XSK_UMEM__DEFAULT_FRAME_SIZE;
		cfg->frame_headroom = XSK_UMEM__DEFAULT_FRAME_HEADROOM;
		cfg->flags = XSK_UMEM__DEFAULT_FLAGS;
		return;
	}

	cfg->fill_size = usr_cfg->fill_size;
	cfg->comp_size = usr_cfg->comp_size;
	cfg->frame_size = usr_cfg->frame_size;
	cfg->frame_headroom = usr_cfg->frame_headroom;
	cfg->flags = usr_cfg->flags;
}

static int xsk_set_xdp_socket_config(struct xsk_socket_config *cfg,
				     const struct xsk_socket_config *usr_cfg)
{
	if (!usr_cfg) {
		cfg->rx_size = XSK_RING_CONS__DEFAULT_NUM_DESCS;
		cfg->tx_size = XSK_RING_PROD__DEFAULT_NUM_DESCS;
		cfg->libbpf_flags = 0;
		cfg->xdp_flags = 0;
		cfg->bind_flags = 0;
		return 0;
	}

	if (usr_cfg->libbpf_flags & ~XSK_LIBBPF_FLAGS__INHIBIT_PROG_LOAD)
		return -EINVAL;

	cfg->rx_size = usr_cfg->rx_size;
	cfg->tx_size = usr_cfg->tx_size;
	cfg->libbpf_flags = usr_cfg->libbpf_flags;
	cfg->xdp_flags = usr_cfg->xdp_flags;
	cfg->bind_flags = usr_cfg->bind_flags;

	return 0;
}

static void xsk_mmap_offsets_v1(struct xdp_mmap_offsets *off)
{
	struct xdp_mmap_offsets_v1 off_v1;

	/* getsockopt on a kernel <= 5.3 has no flags fields.
	 * Copy over the offsets to the correct places in the >=5.4 format
	 * and put the flags where they would have been on that kernel.
	 */
	memcpy(&off_v1, off, sizeof(off_v1));

	off->rx.producer = off_v1.rx.producer;
	off->rx.consumer = off_v1.rx.consumer;
	off->rx.desc = off_v1.rx.desc;
	off->rx.flags = off_v1.rx.consumer + sizeof(__u32);

	off->tx.producer = off_v1.tx.producer;
	off->tx.consumer = off_v1.tx.consumer;
	off->tx.desc = off_v1.tx.desc;
	off->tx.flags = off_v1.tx.consumer + sizeof(__u32);

	off->fr.producer = off_v1.fr.producer;
	off->fr.consumer = off_v1.fr.consumer;
	off->fr.desc = off_v1.fr.desc;
	off->fr.flags = off_v1.fr.consumer + sizeof(__u32);

	off->cr.producer = off_v1.cr.producer;
	off->cr.consumer = off_v1.cr.consumer;
	off->cr.desc = off_v1.cr.desc;
	off->cr.flags = off_v1.cr.consumer + sizeof(__u32);
}

static int xsk_get_mmap_offsets(int fd, struct xdp_mmap_offsets *off)
{
	socklen_t optlen;
	int err;

	optlen = sizeof(*off);
	err = getsockopt(fd, SOL_XDP, XDP_MMAP_OFFSETS, off, &optlen);
	if (err)
		return err;

	if (optlen == sizeof(*off))
		return 0;

	if (optlen == sizeof(struct xdp_mmap_offsets_v1)) {
		xsk_mmap_offsets_v1(off);
		return 0;
	}

	return -EINVAL;
}

static int xsk_create_umem_rings(struct xsk_umem *umem, int fd,
				 struct xsk_ring_prod *fill,
				 struct xsk_ring_cons *comp)
{
	struct xdp_mmap_offsets off;
	void *map;
	int err;

	err = setsockopt(fd, SOL_XDP, XDP_UMEM_FILL_RING,
			 &umem->config.fill_size,
			 sizeof(umem->config.fill_size));
	if (err)
		return -errno;

	err = setsockopt(fd, SOL_XDP, XDP_UMEM_COMPLETION_RING,
			 &umem->config.comp_size,
			 sizeof(umem->config.comp_size));
	if (err)
		return -errno;

	err = xsk_get_mmap_offsets(fd, &off);
	if (err)
		return -errno;

	map = mmap(NULL, off.fr.desc + umem->config.fill_size * sizeof(__u64),
		   PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd,
		   XDP_UMEM_PGOFF_FILL_RING);
	if (map == MAP_FAILED)
		return -errno;

	fill->mask = umem->config.fill_size - 1;
	fill->size = umem->config.fill_size;
	fill->producer = map + off.fr.producer;
	fill->consumer = map + off.fr.consumer;
	fill->flags = map + off.fr.flags;
	fill->ring = map + off.fr.desc;
	fill->cached_cons = umem->config.fill_size;

	map = mmap(NULL, off.cr.desc + umem->config.comp_size * sizeof(__u64),
		   PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE, fd,
		   XDP_UMEM_PGOFF_COMPLETION_RING);
	if (map == MAP_FAILED) {
		err = -errno;
		goto out_mmap;
	}

	comp->mask = umem->config.comp_size - 1;
	comp->size = umem->config.comp_size;
	comp->producer = map + off.cr.producer;
	comp->consumer = map + off.cr.consumer;
	comp->flags = map + off.cr.flags;
	comp->ring = map + off.cr.desc;

	return 0;

out_mmap:
	munmap(map, off.fr.desc + umem->config.fill_size * sizeof(__u64));
	return err;
}

int xsk_umem__create(struct xsk_umem **umem_ptr, void *umem_area,
		     __u64 size, struct xsk_ring_prod *fill,
		     struct xsk_ring_cons *comp,
		     const struct xsk_umem_config *usr_config)
{
	struct xdp_umem_reg mr;
	struct xsk_umem *umem;
	int err;

	if (!umem_area || !umem_ptr || !fill || !comp)
		return -EFAULT;
	if (!size && !xsk_page_aligned(umem_area))
		return -EINVAL;

	umem = calloc(1, sizeof(*umem));
	if (!umem)
		return -ENOMEM;

	umem->fd = socket(AF_XDP, SOCK_RAW | SOCK_CLOEXEC, 0);
	if (umem->fd < 0) {
		err = -errno;
		goto out_umem_alloc;
	}

	umem->umem_area = umem_area;
	INIT_LIST_HEAD(&umem->ctx_list);
	xsk_set_umem_config(&umem->config, usr_config);

	memset(&mr, 0, sizeof(mr));
	mr.addr = (uintptr_t)umem_area;
	mr.len = size;
	mr.chunk_size = umem->config.frame_size;
	mr.headroom = umem->config.frame_headroom;
	mr.flags = umem->config.flags;

	err = setsockopt(umem->fd, SOL_XDP, XDP_UMEM_REG, &mr, sizeof(mr));
	if (err) {
		err = -errno;
		goto out_socket;
	}

	err = xsk_create_umem_rings(umem, umem->fd, fill, comp);
	if (err)
		goto out_socket;

	umem->fill_save = fill;
	umem->comp_save = comp;
	*umem_ptr = umem;
	return 0;

out_socket:
	close(umem->fd);
out_umem_alloc:
	free(umem);
	return err;
}

struct xsk_umem_config_v1 {
	__u32 fill_size;
	__u32 comp_size;
	__u32 frame_size;
	__u32 frame_headroom;
};

static enum xsk_prog get_xsk_prog(void)
{
	enum xsk_prog detected = XSK_PROG_FALLBACK;
	char data_in = 0, data_out;
	struct bpf_insn insns[] = {
		BPF_LD_MAP_FD(BPF_REG_1, 0),
		BPF_MOV64_IMM(BPF_REG_2, 0),
		BPF_MOV64_IMM(BPF_REG_3, XDP_PASS),
		BPF_EMIT_CALL(BPF_FUNC_redirect_map),
		BPF_EXIT_INSN(),
	};
	LIBBPF_OPTS(bpf_test_run_opts, opts,
		.data_in = &data_in,
		.data_size_in = 1,
		.data_out = &data_out,
	);

	int prog_fd, map_fd, ret, insn_cnt = ARRAY_SIZE(insns);

	map_fd = bpf_map_create(BPF_MAP_TYPE_XSKMAP, NULL, sizeof(int), sizeof(int), 1, NULL);
	if (map_fd < 0)
		return detected;

	insns[0].imm = map_fd;

	prog_fd = bpf_prog_load(BPF_PROG_TYPE_XDP, NULL, "GPL", insns, insn_cnt, NULL);
	if (prog_fd < 0) {
		close(map_fd);
		return detected;
	}

	ret = bpf_prog_test_run_opts(prog_fd, &opts);
	if (!ret && opts.retval == XDP_PASS)
		detected = XSK_PROG_REDIRECT_FLAGS;
	close(prog_fd);
	close(map_fd);
	return detected;
}

static int xsk_load_xdp_prog(struct xsk_socket *xsk)
{
	static const int log_buf_size = 16 * 1024;
	struct xsk_ctx *ctx = xsk->ctx;
	char log_buf[log_buf_size];
	int prog_fd;

	/* This is the fallback C-program:
	 * SEC("xdp_sock") int xdp_sock_prog(struct xdp_md *ctx)
	 * {
	 *     int ret, index = ctx->rx_queue_index;
	 *
	 *     // A set entry here means that the correspnding queue_id
	 *     // has an active AF_XDP socket bound to it.
	 *     ret = bpf_redirect_map(&xsks_map, index, XDP_PASS);
	 *     if (ret > 0)
	 *         return ret;
	 *
	 *     // Fallback for pre-5.3 kernels, not supporting default
	 *     // action in the flags parameter.
	 *     if (bpf_map_lookup_elem(&xsks_map, &index))
	 *         return bpf_redirect_map(&xsks_map, index, 0);
	 *     return XDP_PASS;
	 * }
	 */
	struct bpf_insn prog[] = {
		/* r2 = *(u32 *)(r1 + 16) */
		BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 16),
		/* *(u32 *)(r10 - 4) = r2 */
		BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_2, -4),
		/* r1 = xskmap[] */
		BPF_LD_MAP_FD(BPF_REG_1, ctx->xsks_map_fd),
		/* r3 = XDP_PASS */
		BPF_MOV64_IMM(BPF_REG_3, 2),
		/* call bpf_redirect_map */
		BPF_EMIT_CALL(BPF_FUNC_redirect_map),
		/* if w0 != 0 goto pc+13 */
		BPF_JMP32_IMM(BPF_JSGT, BPF_REG_0, 0, 13),
		/* r2 = r10 */
		BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
		/* r2 += -4 */
		BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -4),
		/* r1 = xskmap[] */
		BPF_LD_MAP_FD(BPF_REG_1, ctx->xsks_map_fd),
		/* call bpf_map_lookup_elem */
		BPF_EMIT_CALL(BPF_FUNC_map_lookup_elem),
		/* r1 = r0 */
		BPF_MOV64_REG(BPF_REG_1, BPF_REG_0),
		/* r0 = XDP_PASS */
		BPF_MOV64_IMM(BPF_REG_0, 2),
		/* if r1 == 0 goto pc+5 */
		BPF_JMP_IMM(BPF_JEQ, BPF_REG_1, 0, 5),
		/* r2 = *(u32 *)(r10 - 4) */
		BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_10, -4),
		/* r1 = xskmap[] */
		BPF_LD_MAP_FD(BPF_REG_1, ctx->xsks_map_fd),
		/* r3 = 0 */
		BPF_MOV64_IMM(BPF_REG_3, 0),
		/* call bpf_redirect_map */
		BPF_EMIT_CALL(BPF_FUNC_redirect_map),
		/* The jumps are to this instruction */
		BPF_EXIT_INSN(),
	};

	/* This is the post-5.3 kernel C-program:
	 * SEC("xdp_sock") int xdp_sock_prog(struct xdp_md *ctx)
	 * {
	 *     return bpf_redirect_map(&xsks_map, ctx->rx_queue_index, XDP_PASS);
	 * }
	 */
	struct bpf_insn prog_redirect_flags[] = {
		/* r2 = *(u32 *)(r1 + 16) */
		BPF_LDX_MEM(BPF_W, BPF_REG_2, BPF_REG_1, 16),
		/* r1 = xskmap[] */
		BPF_LD_MAP_FD(BPF_REG_1, ctx->xsks_map_fd),
		/* r3 = XDP_PASS */
		BPF_MOV64_IMM(BPF_REG_3, 2),
		/* call bpf_redirect_map */
		BPF_EMIT_CALL(BPF_FUNC_redirect_map),
		BPF_EXIT_INSN(),
	};
	size_t insns_cnt[] = {ARRAY_SIZE(prog),
			      ARRAY_SIZE(prog_redirect_flags),
	};
	struct bpf_insn *progs[] = {prog, prog_redirect_flags};
	enum xsk_prog option = get_xsk_prog();
	LIBBPF_OPTS(bpf_prog_load_opts, opts,
		.log_buf = log_buf,
		.log_size = log_buf_size,
	);

	prog_fd = bpf_prog_load(BPF_PROG_TYPE_XDP, NULL, "LGPL-2.1 or BSD-2-Clause",
				progs[option], insns_cnt[option], &opts);
	if (prog_fd < 0) {
		pr_warn("BPF log buffer:\n%s", log_buf);
		return prog_fd;
	}

	ctx->prog_fd = prog_fd;
	return 0;
}

static int xsk_create_bpf_link(struct xsk_socket *xsk)
{
	DECLARE_LIBBPF_OPTS(bpf_link_create_opts, opts);
	struct xsk_ctx *ctx = xsk->ctx;
	__u32 prog_id = 0;
	int link_fd;
	int err;

	err = bpf_xdp_query_id(ctx->ifindex, xsk->config.xdp_flags, &prog_id);
	if (err) {
		pr_warn("getting XDP prog id failed\n");
		return err;
	}

	/* if there's a netlink-based XDP prog loaded on interface, bail out
	 * and ask user to do the removal by himself
	 */
	if (prog_id) {
		pr_warn("Netlink-based XDP prog detected, please unload it in order to launch AF_XDP prog\n");
		return -EINVAL;
	}

	opts.flags = xsk->config.xdp_flags & ~(XDP_FLAGS_UPDATE_IF_NOEXIST | XDP_FLAGS_REPLACE);

	link_fd = bpf_link_create(ctx->prog_fd, ctx->ifindex, BPF_XDP, &opts);
	if (link_fd < 0) {
		pr_warn("bpf_link_create failed: %s\n", strerror(errno));
		return link_fd;
	}

	ctx->link_fd = link_fd;
	return 0;
}

/* Copy up to sz - 1 bytes from zero-terminated src string and ensure that dst
 * is zero-terminated string no matter what (unless sz == 0, in which case
 * it's a no-op). It's conceptually close to FreeBSD's strlcpy(), but differs
 * in what is returned. Given this is internal helper, it's trivial to extend
 * this, when necessary. Use this instead of strncpy inside libbpf source code.
 */
static inline void libbpf_strlcpy(char *dst, const char *src, size_t sz)
{
        size_t i;

        if (sz == 0)
                return;

        sz--;
        for (i = 0; i < sz && src[i]; i++)
                dst[i] = src[i];
        dst[i] = '\0';
}

static int xsk_get_max_queues(struct xsk_socket *xsk)
{
	struct ethtool_channels channels = { .cmd = ETHTOOL_GCHANNELS };
	struct xsk_ctx *ctx = xsk->ctx;
	struct ifreq ifr = {};
	int fd, err, ret;

	fd = socket(AF_LOCAL, SOCK_DGRAM | SOCK_CLOEXEC, 0);
	if (fd < 0)
		return -errno;

	ifr.ifr_data = (void *)&channels;
	libbpf_strlcpy(ifr.ifr_name, ctx->ifname, IFNAMSIZ);
	err = ioctl(fd, SIOCETHTOOL, &ifr);
	if (err && errno != EOPNOTSUPP) {
		ret = -errno;
		goto out;
	}

	if (err) {
		/* If the device says it has no channels, then all traffic
		 * is sent to a single stream, so max queues = 1.
		 */
		ret = 1;
	} else {
		/* Take the max of rx, tx, combined. Drivers return
		 * the number of channels in different ways.
		 */
		ret = max(channels.max_rx, channels.max_tx);
		ret = max(ret, (int)channels.max_combined);
	}

out:
	close(fd);
	return ret;
}

static int xsk_create_bpf_maps(struct xsk_socket *xsk)
{
	struct xsk_ctx *ctx = xsk->ctx;
	int max_queues;
	int fd;

	max_queues = xsk_get_max_queues(xsk);
	if (max_queues < 0)
		return max_queues;

	fd = bpf_map_create(BPF_MAP_TYPE_XSKMAP, "xsks_map",
			    sizeof(int), sizeof(int), max_queues, NULL);
	if (fd < 0)
		return fd;

	ctx->xsks_map_fd = fd;

	return 0;
}

static void xsk_delete_bpf_maps(struct xsk_socket *xsk)
{
	struct xsk_ctx *ctx = xsk->ctx;

	bpf_map_delete_elem(ctx->xsks_map_fd, &ctx->queue_id);
	close(ctx->xsks_map_fd);
}

static int xsk_lookup_bpf_maps(struct xsk_socket *xsk)
{
	__u32 i, *map_ids, num_maps, prog_len = sizeof(struct bpf_prog_info);
	__u32 map_len = sizeof(struct bpf_map_info);
	struct bpf_prog_info prog_info = {};
	struct xsk_ctx *ctx = xsk->ctx;
	struct bpf_map_info map_info;
	int fd, err;

	err = bpf_obj_get_info_by_fd(ctx->prog_fd, &prog_info, &prog_len);
	if (err)
		return err;

	num_maps = prog_info.nr_map_ids;

	map_ids = calloc(prog_info.nr_map_ids, sizeof(*map_ids));
	if (!map_ids)
		return -ENOMEM;

	memset(&prog_info, 0, prog_len);
	prog_info.nr_map_ids = num_maps;
	prog_info.map_ids = (__u64)(unsigned long)map_ids;

	err = bpf_obj_get_info_by_fd(ctx->prog_fd, &prog_info, &prog_len);
	if (err)
		goto out_map_ids;

	ctx->xsks_map_fd = -1;

	for (i = 0; i < prog_info.nr_map_ids; i++) {
		fd = bpf_map_get_fd_by_id(map_ids[i]);
		if (fd < 0)
			continue;

		memset(&map_info, 0, map_len);
		err = bpf_obj_get_info_by_fd(fd, &map_info, &map_len);
		if (err) {
			close(fd);
			continue;
		}

		if (!strncmp(map_info.name, "xsks_map", sizeof(map_info.name))) {
			ctx->xsks_map_fd = fd;
			break;
		}

		close(fd);
	}

	if (ctx->xsks_map_fd == -1)
		err = -ENOENT;

out_map_ids:
	free(map_ids);
	return err;
}

static int xsk_set_bpf_maps(struct xsk_socket *xsk)
{
	struct xsk_ctx *ctx = xsk->ctx;

	return bpf_map_update_elem(ctx->xsks_map_fd, &ctx->queue_id,
				   &xsk->fd, 0);
}

static int xsk_link_lookup(int ifindex, __u32 *prog_id, int *link_fd)
{
	struct bpf_link_info link_info;
	__u32 link_len;
	__u32 id = 0;
	int err;
	int fd;

	while (true) {
		err = bpf_link_get_next_id(id, &id);
		if (err) {
			if (errno == ENOENT) {
				err = 0;
				break;
			}
			pr_warn("can't get next link: %s\n", strerror(errno));
			break;
		}

		fd = bpf_link_get_fd_by_id(id);
		if (fd < 0) {
			if (errno == ENOENT)
				continue;
			pr_warn("can't get link by id (%u): %s\n", id, strerror(errno));
			err = -errno;
			break;
		}

		link_len = sizeof(struct bpf_link_info);
		memset(&link_info, 0, link_len);
		err = bpf_obj_get_info_by_fd(fd, &link_info, &link_len);
		if (err) {
			pr_warn("can't get link info: %s\n", strerror(errno));
			close(fd);
			break;
		}
		if (link_info.type == BPF_LINK_TYPE_XDP) {
			if (link_info.xdp.ifindex == ifindex) {
				*link_fd = fd;
				if (prog_id)
					*prog_id = link_info.prog_id;
				break;
			}
		}
		close(fd);
	}

	return err;
}

static bool xsk_probe_bpf_link(void)
{
	LIBBPF_OPTS(bpf_link_create_opts, opts, .flags = XDP_FLAGS_SKB_MODE);
	struct bpf_insn insns[2] = {
		BPF_MOV64_IMM(BPF_REG_0, XDP_PASS),
		BPF_EXIT_INSN()
	};
	int prog_fd, link_fd = -1, insn_cnt = ARRAY_SIZE(insns);
	int ifindex_lo = 1;
	bool ret = false;
	int err;

	err = xsk_link_lookup(ifindex_lo, NULL, &link_fd);
	if (err)
		return ret;

	if (link_fd >= 0)
		return true;

	prog_fd = bpf_prog_load(BPF_PROG_TYPE_XDP, NULL, "GPL", insns, insn_cnt, NULL);
	if (prog_fd < 0)
		return ret;

	link_fd = bpf_link_create(prog_fd, ifindex_lo, BPF_XDP, &opts);
	close(prog_fd);

	if (link_fd >= 0) {
		ret = true;
		close(link_fd);
	}

	return ret;
}

static int xsk_create_xsk_struct(int ifindex, struct xsk_socket *xsk)
{
	char ifname[IFNAMSIZ];
	struct xsk_ctx *ctx;
	char *interface;

	ctx = calloc(1, sizeof(*ctx));
	if (!ctx)
		return -ENOMEM;

	interface = if_indextoname(ifindex, &ifname[0]);
	if (!interface) {
		free(ctx);
		return -errno;
	}

	ctx->ifindex = ifindex;
	libbpf_strlcpy(ctx->ifname, ifname, IFNAMSIZ);

	xsk->ctx = ctx;
	xsk->ctx->has_bpf_link = xsk_probe_bpf_link();

	return 0;
}

static int xsk_init_xdp_res(struct xsk_socket *xsk,
			    int *xsks_map_fd)
{
	struct xsk_ctx *ctx = xsk->ctx;
	int err;

	err = xsk_create_bpf_maps(xsk);
	if (err)
		return err;

	err = xsk_load_xdp_prog(xsk);
	if (err)
		goto err_load_xdp_prog;

	if (ctx->has_bpf_link)
		err = xsk_create_bpf_link(xsk);
	else
		err = bpf_xdp_attach(xsk->ctx->ifindex, ctx->prog_fd,
				     xsk->config.xdp_flags, NULL);

	if (err)
		goto err_attach_xdp_prog;

	if (!xsk->rx)
		return err;

	err = xsk_set_bpf_maps(xsk);
	if (err)
		goto err_set_bpf_maps;

	return err;

err_set_bpf_maps:
	if (ctx->has_bpf_link)
		close(ctx->link_fd);
	else
		bpf_xdp_detach(ctx->ifindex, 0, NULL);
err_attach_xdp_prog:
	close(ctx->prog_fd);
err_load_xdp_prog:
	xsk_delete_bpf_maps(xsk);
	return err;
}

static int xsk_lookup_xdp_res(struct xsk_socket *xsk, int *xsks_map_fd, int prog_id)
{
	struct xsk_ctx *ctx = xsk->ctx;
	int err;

	ctx->prog_fd = bpf_prog_get_fd_by_id(prog_id);
	if (ctx->prog_fd < 0) {
		err = -errno;
		goto err_prog_fd;
	}
	err = xsk_lookup_bpf_maps(xsk);
	if (err)
		goto err_lookup_maps;

	if (!xsk->rx)
		return err;

	err = xsk_set_bpf_maps(xsk);
	if (err)
		goto err_set_maps;

	return err;

err_set_maps:
	close(ctx->xsks_map_fd);
err_lookup_maps:
	close(ctx->prog_fd);
err_prog_fd:
	if (ctx->has_bpf_link)
		close(ctx->link_fd);
	return err;
}

static int __xsk_setup_xdp_prog(struct xsk_socket *_xdp, int *xsks_map_fd)
{
	struct xsk_socket *xsk = _xdp;
	struct xsk_ctx *ctx = xsk->ctx;
	__u32 prog_id = 0;
	int err;

	if (ctx->has_bpf_link)
		err = xsk_link_lookup(ctx->ifindex, &prog_id, &ctx->link_fd);
	else
		err = bpf_xdp_query_id(ctx->ifindex, xsk->config.xdp_flags, &prog_id);

	if (err)
		return err;

	err = !prog_id ? xsk_init_xdp_res(xsk, xsks_map_fd) :
			 xsk_lookup_xdp_res(xsk, xsks_map_fd, prog_id);

	if (!err && xsks_map_fd)
		*xsks_map_fd = ctx->xsks_map_fd;

	return err;
}

int xsk_setup_xdp_prog_xsk(struct xsk_socket *xsk, int *xsks_map_fd)
{
	return __xsk_setup_xdp_prog(xsk, xsks_map_fd);
}

static struct xsk_ctx *xsk_get_ctx(struct xsk_umem *umem, int ifindex,
				   __u32 queue_id)
{
	struct xsk_ctx *ctx;

	if (list_empty(&umem->ctx_list))
		return NULL;

	list_for_each_entry(ctx, &umem->ctx_list, list) {
		if (ctx->ifindex == ifindex && ctx->queue_id == queue_id) {
			ctx->refcount++;
			return ctx;
		}
	}

	return NULL;
}

static void xsk_put_ctx(struct xsk_ctx *ctx, bool unmap)
{
	struct xsk_umem *umem = ctx->umem;
	struct xdp_mmap_offsets off;
	int err;

	if (--ctx->refcount)
		return;

	if (!unmap)
		goto out_free;

	err = xsk_get_mmap_offsets(umem->fd, &off);
	if (err)
		goto out_free;

	munmap(ctx->fill->ring - off.fr.desc, off.fr.desc + umem->config.fill_size *
	       sizeof(__u64));
	munmap(ctx->comp->ring - off.cr.desc, off.cr.desc + umem->config.comp_size *
	       sizeof(__u64));

out_free:
	list_del(&ctx->list);
	free(ctx);
}

static struct xsk_ctx *xsk_create_ctx(struct xsk_socket *xsk,
				      struct xsk_umem *umem, int ifindex,
				      const char *ifname, __u32 queue_id,
				      struct xsk_ring_prod *fill,
				      struct xsk_ring_cons *comp)
{
	struct xsk_ctx *ctx;
	int err;

	ctx = calloc(1, sizeof(*ctx));
	if (!ctx)
		return NULL;

	if (!umem->fill_save) {
		err = xsk_create_umem_rings(umem, xsk->fd, fill, comp);
		if (err) {
			free(ctx);
			return NULL;
		}
	} else if (umem->fill_save != fill || umem->comp_save != comp) {
		/* Copy over rings to new structs. */
		memcpy(fill, umem->fill_save, sizeof(*fill));
		memcpy(comp, umem->comp_save, sizeof(*comp));
	}

	ctx->ifindex = ifindex;
	ctx->refcount = 1;
	ctx->umem = umem;
	ctx->queue_id = queue_id;
	libbpf_strlcpy(ctx->ifname, ifname, IFNAMSIZ);

	ctx->fill = fill;
	ctx->comp = comp;
	list_add(&ctx->list, &umem->ctx_list);
	ctx->has_bpf_link = xsk_probe_bpf_link();
	return ctx;
}

static void xsk_destroy_xsk_struct(struct xsk_socket *xsk)
{
	free(xsk->ctx);
	free(xsk);
}

int xsk_socket__update_xskmap(struct xsk_socket *xsk, int fd)
{
	xsk->ctx->xsks_map_fd = fd;
	return xsk_set_bpf_maps(xsk);
}

int xsk_setup_xdp_prog(int ifindex, int *xsks_map_fd)
{
	struct xsk_socket *xsk;
	int res;

	xsk = calloc(1, sizeof(*xsk));
	if (!xsk)
		return -ENOMEM;

	res = xsk_create_xsk_struct(ifindex, xsk);
	if (res) {
		free(xsk);
		return -EINVAL;
	}

	res = __xsk_setup_xdp_prog(xsk, xsks_map_fd);

	xsk_destroy_xsk_struct(xsk);

	return res;
}

int xsk_socket__create_shared(struct xsk_socket **xsk_ptr,
			      const char *ifname,
			      __u32 queue_id, struct xsk_umem *umem,
			      struct xsk_ring_cons *rx,
			      struct xsk_ring_prod *tx,
			      struct xsk_ring_prod *fill,
			      struct xsk_ring_cons *comp,
			      const struct xsk_socket_config *usr_config)
{
	bool unmap, rx_setup_done = false, tx_setup_done = false;
	void *rx_map = NULL, *tx_map = NULL;
	struct sockaddr_xdp sxdp = {};
	struct xdp_mmap_offsets off;
	struct xsk_socket *xsk;
	struct xsk_ctx *ctx;
	int err, ifindex;

	if (!umem || !xsk_ptr || !(rx || tx))
		return -EFAULT;

	unmap = umem->fill_save != fill;

	xsk = calloc(1, sizeof(*xsk));
	if (!xsk)
		return -ENOMEM;

	err = xsk_set_xdp_socket_config(&xsk->config, usr_config);
	if (err)
		goto out_xsk_alloc;

	xsk->outstanding_tx = 0;
	ifindex = if_nametoindex(ifname);
	if (!ifindex) {
		err = -errno;
		goto out_xsk_alloc;
	}

	if (umem->refcount++ > 0) {
		xsk->fd = socket(AF_XDP, SOCK_RAW | SOCK_CLOEXEC, 0);
		if (xsk->fd < 0) {
			err = -errno;
			goto out_xsk_alloc;
		}
	} else {
		xsk->fd = umem->fd;
		rx_setup_done = umem->rx_ring_setup_done;
		tx_setup_done = umem->tx_ring_setup_done;
	}

	ctx = xsk_get_ctx(umem, ifindex, queue_id);
	if (!ctx) {
		if (!fill || !comp) {
			err = -EFAULT;
			goto out_socket;
		}

		ctx = xsk_create_ctx(xsk, umem, ifindex, ifname, queue_id,
				     fill, comp);
		if (!ctx) {
			err = -ENOMEM;
			goto out_socket;
		}
	}
	xsk->ctx = ctx;

	if (rx && !rx_setup_done) {
		err = setsockopt(xsk->fd, SOL_XDP, XDP_RX_RING,
				 &xsk->config.rx_size,
				 sizeof(xsk->config.rx_size));
		if (err) {
			err = -errno;
			goto out_put_ctx;
		}
		if (xsk->fd == umem->fd)
			umem->rx_ring_setup_done = true;
	}
	if (tx && !tx_setup_done) {
		err = setsockopt(xsk->fd, SOL_XDP, XDP_TX_RING,
				 &xsk->config.tx_size,
				 sizeof(xsk->config.tx_size));
		if (err) {
			err = -errno;
			goto out_put_ctx;
		}
		if (xsk->fd == umem->fd)
			umem->tx_ring_setup_done = true;
	}

	err = xsk_get_mmap_offsets(xsk->fd, &off);
	if (err) {
		err = -errno;
		goto out_put_ctx;
	}

	if (rx) {
		rx_map = mmap(NULL, off.rx.desc +
			      xsk->config.rx_size * sizeof(struct xdp_desc),
			      PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE,
			      xsk->fd, XDP_PGOFF_RX_RING);
		if (rx_map == MAP_FAILED) {
			err = -errno;
			goto out_put_ctx;
		}

		rx->mask = xsk->config.rx_size - 1;
		rx->size = xsk->config.rx_size;
		rx->producer = rx_map + off.rx.producer;
		rx->consumer = rx_map + off.rx.consumer;
		rx->flags = rx_map + off.rx.flags;
		rx->ring = rx_map + off.rx.desc;
		rx->cached_prod = *rx->producer;
		rx->cached_cons = *rx->consumer;
	}
	xsk->rx = rx;

	if (tx) {
		tx_map = mmap(NULL, off.tx.desc +
			      xsk->config.tx_size * sizeof(struct xdp_desc),
			      PROT_READ | PROT_WRITE, MAP_SHARED | MAP_POPULATE,
			      xsk->fd, XDP_PGOFF_TX_RING);
		if (tx_map == MAP_FAILED) {
			err = -errno;
			goto out_mmap_rx;
		}

		tx->mask = xsk->config.tx_size - 1;
		tx->size = xsk->config.tx_size;
		tx->producer = tx_map + off.tx.producer;
		tx->consumer = tx_map + off.tx.consumer;
		tx->flags = tx_map + off.tx.flags;
		tx->ring = tx_map + off.tx.desc;
		tx->cached_prod = *tx->producer;
		/* cached_cons is r->size bigger than the real consumer pointer
		 * See xsk_prod_nb_free
		 */
		tx->cached_cons = *tx->consumer + xsk->config.tx_size;
	}
	xsk->tx = tx;

	sxdp.sxdp_family = PF_XDP;
	sxdp.sxdp_ifindex = ctx->ifindex;
	sxdp.sxdp_queue_id = ctx->queue_id;
	if (umem->refcount > 1) {
		sxdp.sxdp_flags |= XDP_SHARED_UMEM;
		sxdp.sxdp_shared_umem_fd = umem->fd;
	} else {
		sxdp.sxdp_flags = xsk->config.bind_flags;
	}

	err = bind(xsk->fd, (struct sockaddr *)&sxdp, sizeof(sxdp));
	if (err) {
		err = -errno;
		goto out_mmap_tx;
	}

	if (!(xsk->config.libbpf_flags & XSK_LIBBPF_FLAGS__INHIBIT_PROG_LOAD)) {
		err = __xsk_setup_xdp_prog(xsk, NULL);
		if (err)
			goto out_mmap_tx;
	}

	*xsk_ptr = xsk;
	umem->fill_save = NULL;
	umem->comp_save = NULL;
	return 0;

out_mmap_tx:
	if (tx)
		munmap(tx_map, off.tx.desc +
		       xsk->config.tx_size * sizeof(struct xdp_desc));
out_mmap_rx:
	if (rx)
		munmap(rx_map, off.rx.desc +
		       xsk->config.rx_size * sizeof(struct xdp_desc));
out_put_ctx:
	xsk_put_ctx(ctx, unmap);
out_socket:
	if (--umem->refcount)
		close(xsk->fd);
out_xsk_alloc:
	free(xsk);
	return err;
}

int xsk_socket__create(struct xsk_socket **xsk_ptr, const char *ifname,
		       __u32 queue_id, struct xsk_umem *umem,
		       struct xsk_ring_cons *rx, struct xsk_ring_prod *tx,
		       const struct xsk_socket_config *usr_config)
{
	if (!umem)
		return -EFAULT;

	return xsk_socket__create_shared(xsk_ptr, ifname, queue_id, umem,
					 rx, tx, umem->fill_save,
					 umem->comp_save, usr_config);
}

int xsk_umem__delete(struct xsk_umem *umem)
{
	struct xdp_mmap_offsets off;
	int err;

	if (!umem)
		return 0;

	if (umem->refcount)
		return -EBUSY;

	err = xsk_get_mmap_offsets(umem->fd, &off);
	if (!err && umem->fill_save && umem->comp_save) {
		munmap(umem->fill_save->ring - off.fr.desc,
		       off.fr.desc + umem->config.fill_size * sizeof(__u64));
		munmap(umem->comp_save->ring - off.cr.desc,
		       off.cr.desc + umem->config.comp_size * sizeof(__u64));
	}

	close(umem->fd);
	free(umem);

	return 0;
}

void xsk_socket__delete(struct xsk_socket *xsk)
{
	size_t desc_sz = sizeof(struct xdp_desc);
	struct xdp_mmap_offsets off;
	struct xsk_umem *umem;
	struct xsk_ctx *ctx;
	int err;

	if (!xsk)
		return;

	ctx = xsk->ctx;
	umem = ctx->umem;

	if (ctx->refcount == 1) {
		xsk_delete_bpf_maps(xsk);
		close(ctx->prog_fd);
		if (ctx->has_bpf_link)
			close(ctx->link_fd);
	}

	xsk_put_ctx(ctx, true);

	err = xsk_get_mmap_offsets(xsk->fd, &off);
	if (!err) {
		if (xsk->rx) {
			munmap(xsk->rx->ring - off.rx.desc,
			       off.rx.desc + xsk->config.rx_size * desc_sz);
		}
		if (xsk->tx) {
			munmap(xsk->tx->ring - off.tx.desc,
			       off.tx.desc + xsk->config.tx_size * desc_sz);
		}
	}

	umem->refcount--;
	/* Do not close an fd that also has an associated umem connected
	 * to it.
	 */
	if (xsk->fd != umem->fd)
		close(xsk->fd);
	free(xsk);
}