summaryrefslogtreecommitdiffstats
path: root/net/ipv4/fou.c
blob: a0586b4a197d9eba50e742cede9f826e432ae5c2 (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
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/socket.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <linux/udp.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <net/genetlink.h>
#include <net/gue.h>
#include <net/ip.h>
#include <net/protocol.h>
#include <net/udp.h>
#include <net/udp_tunnel.h>
#include <net/xfrm.h>
#include <uapi/linux/fou.h>
#include <uapi/linux/genetlink.h>

struct fou {
	struct socket *sock;
	u8 protocol;
	u8 flags;
	__be16 port;
	u16 type;
	struct udp_offload udp_offloads;
	struct list_head list;
	struct rcu_head rcu;
};

#define FOU_F_REMCSUM_NOPARTIAL BIT(0)

struct fou_cfg {
	u16 type;
	u8 protocol;
	u8 flags;
	struct udp_port_cfg udp_config;
};

static unsigned int fou_net_id;

struct fou_net {
	struct list_head fou_list;
	struct mutex fou_lock;
};

static inline struct fou *fou_from_sock(struct sock *sk)
{
	return sk->sk_user_data;
}

static int fou_recv_pull(struct sk_buff *skb, size_t len)
{
	struct iphdr *iph = ip_hdr(skb);

	/* Remove 'len' bytes from the packet (UDP header and
	 * FOU header if present).
	 */
	iph->tot_len = htons(ntohs(iph->tot_len) - len);
	__skb_pull(skb, len);
	skb_postpull_rcsum(skb, udp_hdr(skb), len);
	skb_reset_transport_header(skb);
	return iptunnel_pull_offloads(skb);
}

static int fou_udp_recv(struct sock *sk, struct sk_buff *skb)
{
	struct fou *fou = fou_from_sock(sk);

	if (!fou)
		return 1;

	if (fou_recv_pull(skb, sizeof(struct udphdr)))
		goto drop;

	return -fou->protocol;

drop:
	kfree_skb(skb);
	return 0;
}

static struct guehdr *gue_remcsum(struct sk_buff *skb, struct guehdr *guehdr,
				  void *data, size_t hdrlen, u8 ipproto,
				  bool nopartial)
{
	__be16 *pd = data;
	size_t start = ntohs(pd[0]);
	size_t offset = ntohs(pd[1]);
	size_t plen = sizeof(struct udphdr) + hdrlen +
	    max_t(size_t, offset + sizeof(u16), start);

	if (skb->remcsum_offload)
		return guehdr;

	if (!pskb_may_pull(skb, plen))
		return NULL;
	guehdr = (struct guehdr *)&udp_hdr(skb)[1];

	skb_remcsum_process(skb, (void *)guehdr + hdrlen,
			    start, offset, nopartial);

	return guehdr;
}

static int gue_control_message(struct sk_buff *skb, struct guehdr *guehdr)
{
	/* No support yet */
	kfree_skb(skb);
	return 0;
}

static int gue_udp_recv(struct sock *sk, struct sk_buff *skb)
{
	struct fou *fou = fou_from_sock(sk);
	size_t len, optlen, hdrlen;
	struct guehdr *guehdr;
	void *data;
	u16 doffset = 0;

	if (!fou)
		return 1;

	len = sizeof(struct udphdr) + sizeof(struct guehdr);
	if (!pskb_may_pull(skb, len))
		goto drop;

	guehdr = (struct guehdr *)&udp_hdr(skb)[1];

	optlen = guehdr->hlen << 2;
	len += optlen;

	if (!pskb_may_pull(skb, len))
		goto drop;

	/* guehdr may change after pull */
	guehdr = (struct guehdr *)&udp_hdr(skb)[1];

	hdrlen = sizeof(struct guehdr) + optlen;

	if (guehdr->version != 0 || validate_gue_flags(guehdr, optlen))
		goto drop;

	hdrlen = sizeof(struct guehdr) + optlen;

	ip_hdr(skb)->tot_len = htons(ntohs(ip_hdr(skb)->tot_len) - len);

	/* Pull csum through the guehdr now . This can be used if
	 * there is a remote checksum offload.
	 */
	skb_postpull_rcsum(skb, udp_hdr(skb), len);

	data = &guehdr[1];

	if (guehdr->flags & GUE_FLAG_PRIV) {
		__be32 flags = *(__be32 *)(data + doffset);

		doffset += GUE_LEN_PRIV;

		if (flags & GUE_PFLAG_REMCSUM) {
			guehdr = gue_remcsum(skb, guehdr, data + doffset,
					     hdrlen, guehdr->proto_ctype,
					     !!(fou->flags &
						FOU_F_REMCSUM_NOPARTIAL));
			if (!guehdr)
				goto drop;

			data = &guehdr[1];

			doffset += GUE_PLEN_REMCSUM;
		}
	}

	if (unlikely(guehdr->control))
		return gue_control_message(skb, guehdr);

	__skb_pull(skb, sizeof(struct udphdr) + hdrlen);
	skb_reset_transport_header(skb);

	if (iptunnel_pull_offloads(skb))
		goto drop;

	return -guehdr->proto_ctype;

drop:
	kfree_skb(skb);
	return 0;
}

static struct sk_buff **fou_gro_receive(struct sk_buff **head,
					struct sk_buff *skb,
					struct udp_offload *uoff)
{
	const struct net_offload *ops;
	struct sk_buff **pp = NULL;
	u8 proto = NAPI_GRO_CB(skb)->proto;
	const struct net_offload **offloads;

	rcu_read_lock();
	offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
	ops = rcu_dereference(offloads[proto]);
	if (!ops || !ops->callbacks.gro_receive)
		goto out_unlock;

	pp = ops->callbacks.gro_receive(head, skb);

out_unlock:
	rcu_read_unlock();

	return pp;
}

static int fou_gro_complete(struct sk_buff *skb, int nhoff,
			    struct udp_offload *uoff)
{
	const struct net_offload *ops;
	u8 proto = NAPI_GRO_CB(skb)->proto;
	int err = -ENOSYS;
	const struct net_offload **offloads;

	udp_tunnel_gro_complete(skb, nhoff);

	rcu_read_lock();
	offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
	ops = rcu_dereference(offloads[proto]);
	if (WARN_ON(!ops || !ops->callbacks.gro_complete))
		goto out_unlock;

	err = ops->callbacks.gro_complete(skb, nhoff);

out_unlock:
	rcu_read_unlock();

	return err;
}

static struct guehdr *gue_gro_remcsum(struct sk_buff *skb, unsigned int off,
				      struct guehdr *guehdr, void *data,
				      size_t hdrlen, struct gro_remcsum *grc,
				      bool nopartial)
{
	__be16 *pd = data;
	size_t start = ntohs(pd[0]);
	size_t offset = ntohs(pd[1]);

	if (skb->remcsum_offload)
		return guehdr;

	if (!NAPI_GRO_CB(skb)->csum_valid)
		return NULL;

	guehdr = skb_gro_remcsum_process(skb, (void *)guehdr, off, hdrlen,
					 start, offset, grc, nopartial);

	skb->remcsum_offload = 1;

	return guehdr;
}

static struct sk_buff **gue_gro_receive(struct sk_buff **head,
					struct sk_buff *skb,
					struct udp_offload *uoff)
{
	const struct net_offload **offloads;
	const struct net_offload *ops;
	struct sk_buff **pp = NULL;
	struct sk_buff *p;
	struct guehdr *guehdr;
	size_t len, optlen, hdrlen, off;
	void *data;
	u16 doffset = 0;
	int flush = 1;
	struct fou *fou = container_of(uoff, struct fou, udp_offloads);
	struct gro_remcsum grc;

	skb_gro_remcsum_init(&grc);

	off = skb_gro_offset(skb);
	len = off + sizeof(*guehdr);

	guehdr = skb_gro_header_fast(skb, off);
	if (skb_gro_header_hard(skb, len)) {
		guehdr = skb_gro_header_slow(skb, len, off);
		if (unlikely(!guehdr))
			goto out;
	}

	optlen = guehdr->hlen << 2;
	len += optlen;

	if (skb_gro_header_hard(skb, len)) {
		guehdr = skb_gro_header_slow(skb, len, off);
		if (unlikely(!guehdr))
			goto out;
	}

	if (unlikely(guehdr->control) || guehdr->version != 0 ||
	    validate_gue_flags(guehdr, optlen))
		goto out;

	hdrlen = sizeof(*guehdr) + optlen;

	/* Adjust NAPI_GRO_CB(skb)->csum to account for guehdr,
	 * this is needed if there is a remote checkcsum offload.
	 */
	skb_gro_postpull_rcsum(skb, guehdr, hdrlen);

	data = &guehdr[1];

	if (guehdr->flags & GUE_FLAG_PRIV) {
		__be32 flags = *(__be32 *)(data + doffset);

		doffset += GUE_LEN_PRIV;

		if (flags & GUE_PFLAG_REMCSUM) {
			guehdr = gue_gro_remcsum(skb, off, guehdr,
						 data + doffset, hdrlen, &grc,
						 !!(fou->flags &
						    FOU_F_REMCSUM_NOPARTIAL));

			if (!guehdr)
				goto out;

			data = &guehdr[1];

			doffset += GUE_PLEN_REMCSUM;
		}
	}

	skb_gro_pull(skb, hdrlen);

	for (p = *head; p; p = p->next) {
		const struct guehdr *guehdr2;

		if (!NAPI_GRO_CB(p)->same_flow)
			continue;

		guehdr2 = (struct guehdr *)(p->data + off);

		/* Compare base GUE header to be equal (covers
		 * hlen, version, proto_ctype, and flags.
		 */
		if (guehdr->word != guehdr2->word) {
			NAPI_GRO_CB(p)->same_flow = 0;
			continue;
		}

		/* Compare optional fields are the same. */
		if (guehdr->hlen && memcmp(&guehdr[1], &guehdr2[1],
					   guehdr->hlen << 2)) {
			NAPI_GRO_CB(p)->same_flow = 0;
			continue;
		}
	}

	rcu_read_lock();
	offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
	ops = rcu_dereference(offloads[guehdr->proto_ctype]);
	if (WARN_ON_ONCE(!ops || !ops->callbacks.gro_receive))
		goto out_unlock;

	pp = ops->callbacks.gro_receive(head, skb);
	flush = 0;

out_unlock:
	rcu_read_unlock();
out:
	NAPI_GRO_CB(skb)->flush |= flush;
	skb_gro_remcsum_cleanup(skb, &grc);

	return pp;
}

static int gue_gro_complete(struct sk_buff *skb, int nhoff,
			    struct udp_offload *uoff)
{
	const struct net_offload **offloads;
	struct guehdr *guehdr = (struct guehdr *)(skb->data + nhoff);
	const struct net_offload *ops;
	unsigned int guehlen;
	u8 proto;
	int err = -ENOENT;

	proto = guehdr->proto_ctype;

	guehlen = sizeof(*guehdr) + (guehdr->hlen << 2);

	rcu_read_lock();
	offloads = NAPI_GRO_CB(skb)->is_ipv6 ? inet6_offloads : inet_offloads;
	ops = rcu_dereference(offloads[proto]);
	if (WARN_ON(!ops || !ops->callbacks.gro_complete))
		goto out_unlock;

	err = ops->callbacks.gro_complete(skb, nhoff + guehlen);

out_unlock:
	rcu_read_unlock();
	return err;
}

static int fou_add_to_port_list(struct net *net, struct fou *fou)
{
	struct fou_net *fn = net_generic(net, fou_net_id);
	struct fou *fout;

	mutex_lock(&fn->fou_lock);
	list_for_each_entry(fout, &fn->fou_list, list) {
		if (fou->port == fout->port) {
			mutex_unlock(&fn->fou_lock);
			return -EALREADY;
		}
	}

	list_add(&fou->list, &fn->fou_list);
	mutex_unlock(&fn->fou_lock);

	return 0;
}

static void fou_release(struct fou *fou)
{
	struct socket *sock = fou->sock;
	struct sock *sk = sock->sk;

	if (sk->sk_family == AF_INET)
		udp_del_offload(&fou->udp_offloads);
	list_del(&fou->list);
	udp_tunnel_sock_release(sock);

	kfree_rcu(fou, rcu);
}

static int fou_encap_init(struct sock *sk, struct fou *fou, struct fou_cfg *cfg)
{
	udp_sk(sk)->encap_rcv = fou_udp_recv;
	fou->protocol = cfg->protocol;
	fou->udp_offloads.callbacks.gro_receive = fou_gro_receive;
	fou->udp_offloads.callbacks.gro_complete = fou_gro_complete;
	fou->udp_offloads.port = cfg->udp_config.local_udp_port;
	fou->udp_offloads.ipproto = cfg->protocol;

	return 0;
}

static int gue_encap_init(struct sock *sk, struct fou *fou, struct fou_cfg *cfg)
{
	udp_sk(sk)->encap_rcv = gue_udp_recv;
	fou->udp_offloads.callbacks.gro_receive = gue_gro_receive;
	fou->udp_offloads.callbacks.gro_complete = gue_gro_complete;
	fou->udp_offloads.port = cfg->udp_config.local_udp_port;

	return 0;
}

static int fou_create(struct net *net, struct fou_cfg *cfg,
		      struct socket **sockp)
{
	struct socket *sock = NULL;
	struct fou *fou = NULL;
	struct sock *sk;
	int err;

	/* Open UDP socket */
	err = udp_sock_create(net, &cfg->udp_config, &sock);
	if (err < 0)
		goto error;

	/* Allocate FOU port structure */
	fou = kzalloc(sizeof(*fou), GFP_KERNEL);
	if (!fou) {
		err = -ENOMEM;
		goto error;
	}

	sk = sock->sk;

	fou->flags = cfg->flags;
	fou->port = cfg->udp_config.local_udp_port;

	/* Initial for fou type */
	switch (cfg->type) {
	case FOU_ENCAP_DIRECT:
		err = fou_encap_init(sk, fou, cfg);
		if (err)
			goto error;
		break;
	case FOU_ENCAP_GUE:
		err = gue_encap_init(sk, fou, cfg);
		if (err)
			goto error;
		break;
	default:
		err = -EINVAL;
		goto error;
	}

	fou->type = cfg->type;

	udp_sk(sk)->encap_type = 1;
	udp_encap_enable();

	sk->sk_user_data = fou;
	fou->sock = sock;

	inet_inc_convert_csum(sk);

	sk->sk_allocation = GFP_ATOMIC;

	if (cfg->udp_config.family == AF_INET) {
		err = udp_add_offload(net, &fou->udp_offloads);
		if (err)
			goto error;
	}

	err = fou_add_to_port_list(net, fou);
	if (err)
		goto error;

	if (sockp)
		*sockp = sock;

	return 0;

error:
	kfree(fou);
	if (sock)
		udp_tunnel_sock_release(sock);

	return err;
}

static int fou_destroy(struct net *net, struct fou_cfg *cfg)
{
	struct fou_net *fn = net_generic(net, fou_net_id);
	__be16 port = cfg->udp_config.local_udp_port;
	int err = -EINVAL;
	struct fou *fou;

	mutex_lock(&fn->fou_lock);
	list_for_each_entry(fou, &fn->fou_list, list) {
		if (fou->port == port) {
			fou_release(fou);
			err = 0;
			break;
		}
	}
	mutex_unlock(&fn->fou_lock);

	return err;
}

static struct genl_family fou_nl_family = {
	.id		= GENL_ID_GENERATE,
	.hdrsize	= 0,
	.name		= FOU_GENL_NAME,
	.version	= FOU_GENL_VERSION,
	.maxattr	= FOU_ATTR_MAX,
	.netnsok	= true,
};

static struct nla_policy fou_nl_policy[FOU_ATTR_MAX + 1] = {
	[FOU_ATTR_PORT] = { .type = NLA_U16, },
	[FOU_ATTR_AF] = { .type = NLA_U8, },
	[FOU_ATTR_IPPROTO] = { .type = NLA_U8, },
	[FOU_ATTR_TYPE] = { .type = NLA_U8, },
	[FOU_ATTR_REMCSUM_NOPARTIAL] = { .type = NLA_FLAG, },
};

static int parse_nl_config(struct genl_info *info,
			   struct fou_cfg *cfg)
{
	memset(cfg, 0, sizeof(*cfg));

	cfg->udp_config.family = AF_INET;

	if (info->attrs[FOU_ATTR_AF]) {
		u8 family = nla_get_u8(info->attrs[FOU_ATTR_AF]);

		if (family != AF_INET)
			return -EINVAL;

		cfg->udp_config.family = family;
	}

	if (info->attrs[FOU_ATTR_PORT]) {
		__be16 port = nla_get_be16(info->attrs[FOU_ATTR_PORT]);

		cfg->udp_config.local_udp_port = port;
	}

	if (info->attrs[FOU_ATTR_IPPROTO])
		cfg->protocol = nla_get_u8(info->attrs[FOU_ATTR_IPPROTO]);

	if (info->attrs[FOU_ATTR_TYPE])
		cfg->type = nla_get_u8(info->attrs[FOU_ATTR_TYPE]);

	if (info->attrs[FOU_ATTR_REMCSUM_NOPARTIAL])
		cfg->flags |= FOU_F_REMCSUM_NOPARTIAL;

	return 0;
}

static int fou_nl_cmd_add_port(struct sk_buff *skb, struct genl_info *info)
{
	struct net *net = genl_info_net(info);
	struct fou_cfg cfg;
	int err;

	err = parse_nl_config(info, &cfg);
	if (err)
		return err;

	return fou_create(net, &cfg, NULL);
}

static int fou_nl_cmd_rm_port(struct sk_buff *skb, struct genl_info *info)
{
	struct net *net = genl_info_net(info);
	struct fou_cfg cfg;
	int err;

	err = parse_nl_config(info, &cfg);
	if (err)
		return err;

	return fou_destroy(net, &cfg);
}

static int fou_fill_info(struct fou *fou, struct sk_buff *msg)
{
	if (nla_put_u8(msg, FOU_ATTR_AF, fou->sock->sk->sk_family) ||
	    nla_put_be16(msg, FOU_ATTR_PORT, fou->port) ||
	    nla_put_u8(msg, FOU_ATTR_IPPROTO, fou->protocol) ||
	    nla_put_u8(msg, FOU_ATTR_TYPE, fou->type))
		return -1;

	if (fou->flags & FOU_F_REMCSUM_NOPARTIAL)
		if (nla_put_flag(msg, FOU_ATTR_REMCSUM_NOPARTIAL))
			return -1;
	return 0;
}

static int fou_dump_info(struct fou *fou, u32 portid, u32 seq,
			 u32 flags, struct sk_buff *skb, u8 cmd)
{
	void *hdr;

	hdr = genlmsg_put(skb, portid, seq, &fou_nl_family, flags, cmd);
	if (!hdr)
		return -ENOMEM;

	if (fou_fill_info(fou, skb) < 0)
		goto nla_put_failure;

	genlmsg_end(skb, hdr);
	return 0;

nla_put_failure:
	genlmsg_cancel(skb, hdr);
	return -EMSGSIZE;
}

static int fou_nl_cmd_get_port(struct sk_buff *skb, struct genl_info *info)
{
	struct net *net = genl_info_net(info);
	struct fou_net *fn = net_generic(net, fou_net_id);
	struct sk_buff *msg;
	struct fou_cfg cfg;
	struct fou *fout;
	__be16 port;
	int ret;

	ret = parse_nl_config(info, &cfg);
	if (ret)
		return ret;
	port = cfg.udp_config.local_udp_port;
	if (port == 0)
		return -EINVAL;

	msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
	if (!msg)
		return -ENOMEM;

	ret = -ESRCH;
	mutex_lock(&fn->fou_lock);
	list_for_each_entry(fout, &fn->fou_list, list) {
		if (port == fout->port) {
			ret = fou_dump_info(fout, info->snd_portid,
					    info->snd_seq, 0, msg,
					    info->genlhdr->cmd);
			break;
		}
	}
	mutex_unlock(&fn->fou_lock);
	if (ret < 0)
		goto out_free;

	return genlmsg_reply(msg, info);

out_free:
	nlmsg_free(msg);
	return ret;
}

static int fou_nl_dump(struct sk_buff *skb, struct netlink_callback *cb)
{
	struct net *net = sock_net(skb->sk);
	struct fou_net *fn = net_generic(net, fou_net_id);
	struct fou *fout;
	int idx = 0, ret;

	mutex_lock(&fn->fou_lock);
	list_for_each_entry(fout, &fn->fou_list, list) {
		if (idx++ < cb->args[0])
			continue;
		ret = fou_dump_info(fout, NETLINK_CB(cb->skb).portid,
				    cb->nlh->nlmsg_seq, NLM_F_MULTI,
				    skb, FOU_CMD_GET);
		if (ret)
			break;
	}
	mutex_unlock(&fn->fou_lock);

	cb->args[0] = idx;
	return skb->len;
}

static const struct genl_ops fou_nl_ops[] = {
	{
		.cmd = FOU_CMD_ADD,
		.doit = fou_nl_cmd_add_port,
		.policy = fou_nl_policy,
		.flags = GENL_ADMIN_PERM,
	},
	{
		.cmd = FOU_CMD_DEL,
		.doit = fou_nl_cmd_rm_port,
		.policy = fou_nl_policy,
		.flags = GENL_ADMIN_PERM,
	},
	{
		.cmd = FOU_CMD_GET,
		.doit = fou_nl_cmd_get_port,
		.dumpit = fou_nl_dump,
		.policy = fou_nl_policy,
	},
};

size_t fou_encap_hlen(struct ip_tunnel_encap *e)
{
	return sizeof(struct udphdr);
}
EXPORT_SYMBOL(fou_encap_hlen);

size_t gue_encap_hlen(struct ip_tunnel_encap *e)
{
	size_t len;
	bool need_priv = false;

	len = sizeof(struct udphdr) + sizeof(struct guehdr);

	if (e->flags & TUNNEL_ENCAP_FLAG_REMCSUM) {
		len += GUE_PLEN_REMCSUM;
		need_priv = true;
	}

	len += need_priv ? GUE_LEN_PRIV : 0;

	return len;
}
EXPORT_SYMBOL(gue_encap_hlen);

static void fou_build_udp(struct sk_buff *skb, struct ip_tunnel_encap *e,
			  struct flowi4 *fl4, u8 *protocol, __be16 sport)
{
	struct udphdr *uh;

	skb_push(skb, sizeof(struct udphdr));
	skb_reset_transport_header(skb);

	uh = udp_hdr(skb);

	uh->dest = e->dport;
	uh->source = sport;
	uh->len = htons(skb->len);
	udp_set_csum(!(e->flags & TUNNEL_ENCAP_FLAG_CSUM), skb,
		     fl4->saddr, fl4->daddr, skb->len);

	*protocol = IPPROTO_UDP;
}

int fou_build_header(struct sk_buff *skb, struct ip_tunnel_encap *e,
		     u8 *protocol, struct flowi4 *fl4)
{
	int type = e->flags & TUNNEL_ENCAP_FLAG_CSUM ? SKB_GSO_UDP_TUNNEL_CSUM :
						       SKB_GSO_UDP_TUNNEL;
	__be16 sport;

	skb = iptunnel_handle_offloads(skb, type);

	if (IS_ERR(skb))
		return PTR_ERR(skb);

	sport = e->sport ? : udp_flow_src_port(dev_net(skb->dev),
					       skb, 0, 0, false);
	fou_build_udp(skb, e, fl4, protocol, sport);

	return 0;
}
EXPORT_SYMBOL(fou_build_header);

int gue_build_header(struct sk_buff *skb, struct ip_tunnel_encap *e,
		     u8 *protocol, struct flowi4 *fl4)
{
	int type = e->flags & TUNNEL_ENCAP_FLAG_CSUM ? SKB_GSO_UDP_TUNNEL_CSUM :
						       SKB_GSO_UDP_TUNNEL;
	struct guehdr *guehdr;
	size_t hdrlen, optlen = 0;
	__be16 sport;
	void *data;
	bool need_priv = false;

	if ((e->flags & TUNNEL_ENCAP_FLAG_REMCSUM) &&
	    skb->ip_summed == CHECKSUM_PARTIAL) {
		optlen += GUE_PLEN_REMCSUM;
		type |= SKB_GSO_TUNNEL_REMCSUM;
		need_priv = true;
	}

	optlen += need_priv ? GUE_LEN_PRIV : 0;

	skb = iptunnel_handle_offloads(skb, type);

	if (IS_ERR(skb))
		return PTR_ERR(skb);

	/* Get source port (based on flow hash) before skb_push */
	sport = e->sport ? : udp_flow_src_port(dev_net(skb->dev),
					       skb, 0, 0, false);

	hdrlen = sizeof(struct guehdr) + optlen;

	skb_push(skb, hdrlen);

	guehdr = (struct guehdr *)skb->data;

	guehdr->control = 0;
	guehdr->version = 0;
	guehdr->hlen = optlen >> 2;
	guehdr->flags = 0;
	guehdr->proto_ctype = *protocol;

	data = &guehdr[1];

	if (need_priv) {
		__be32 *flags = data;

		guehdr->flags |= GUE_FLAG_PRIV;
		*flags = 0;
		data += GUE_LEN_PRIV;

		if (type & SKB_GSO_TUNNEL_REMCSUM) {
			u16 csum_start = skb_checksum_start_offset(skb);
			__be16 *pd = data;

			if (csum_start < hdrlen)
				return -EINVAL;

			csum_start -= hdrlen;
			pd[0] = htons(csum_start);
			pd[1] = htons(csum_start + skb->csum_offset);

			if (!skb_is_gso(skb)) {
				skb->ip_summed = CHECKSUM_NONE;
				skb->encapsulation = 0;
			}

			*flags |= GUE_PFLAG_REMCSUM;
			data += GUE_PLEN_REMCSUM;
		}

	}

	fou_build_udp(skb, e, fl4, protocol, sport);

	return 0;
}
EXPORT_SYMBOL(gue_build_header);

#ifdef CONFIG_NET_FOU_IP_TUNNELS

static const struct ip_tunnel_encap_ops fou_iptun_ops = {
	.encap_hlen = fou_encap_hlen,
	.build_header = fou_build_header,
};

static const struct ip_tunnel_encap_ops gue_iptun_ops = {
	.encap_hlen = gue_encap_hlen,
	.build_header = gue_build_header,
};

static int ip_tunnel_encap_add_fou_ops(void)
{
	int ret;

	ret = ip_tunnel_encap_add_ops(&fou_iptun_ops, TUNNEL_ENCAP_FOU);
	if (ret < 0) {
		pr_err("can't add fou ops\n");
		return ret;
	}

	ret = ip_tunnel_encap_add_ops(&gue_iptun_ops, TUNNEL_ENCAP_GUE);
	if (ret < 0) {
		pr_err("can't add gue ops\n");
		ip_tunnel_encap_del_ops(&fou_iptun_ops, TUNNEL_ENCAP_FOU);
		return ret;
	}

	return 0;
}

static void ip_tunnel_encap_del_fou_ops(void)
{
	ip_tunnel_encap_del_ops(&fou_iptun_ops, TUNNEL_ENCAP_FOU);
	ip_tunnel_encap_del_ops(&gue_iptun_ops, TUNNEL_ENCAP_GUE);
}

#else

static int ip_tunnel_encap_add_fou_ops(void)
{
	return 0;
}

static void ip_tunnel_encap_del_fou_ops(void)
{
}

#endif

static __net_init int fou_init_net(struct net *net)
{
	struct fou_net *fn = net_generic(net, fou_net_id);

	INIT_LIST_HEAD(&fn->fou_list);
	mutex_init(&fn->fou_lock);
	return 0;
}

static __net_exit void fou_exit_net(struct net *net)
{
	struct fou_net *fn = net_generic(net, fou_net_id);
	struct fou *fou, *next;

	/* Close all the FOU sockets */
	mutex_lock(&fn->fou_lock);
	list_for_each_entry_safe(fou, next, &fn->fou_list, list)
		fou_release(fou);
	mutex_unlock(&fn->fou_lock);
}

static struct pernet_operations fou_net_ops = {
	.init = fou_init_net,
	.exit = fou_exit_net,
	.id   = &fou_net_id,
	.size = sizeof(struct fou_net),
};

static int __init fou_init(void)
{
	int ret;

	ret = register_pernet_device(&fou_net_ops);
	if (ret)
		goto exit;

	ret = genl_register_family_with_ops(&fou_nl_family,
					    fou_nl_ops);
	if (ret < 0)
		goto unregister;

	ret = ip_tunnel_encap_add_fou_ops();
	if (ret == 0)
		return 0;

	genl_unregister_family(&fou_nl_family);
unregister:
	unregister_pernet_device(&fou_net_ops);
exit:
	return ret;
}

static void __exit fou_fini(void)
{
	ip_tunnel_encap_del_fou_ops();
	genl_unregister_family(&fou_nl_family);
	unregister_pernet_device(&fou_net_ops);
}

module_init(fou_init);
module_exit(fou_fini);
MODULE_AUTHOR("Tom Herbert <therbert@google.com>");
MODULE_LICENSE("GPL");
OpenPOWER on IntegriCloud