summaryrefslogtreecommitdiffstats
path: root/net/smc/smc_clc.c
blob: 6ec1ebe878ae0ee967da04f76757261854012372 (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
// SPDX-License-Identifier: GPL-2.0
/*
 *  Shared Memory Communications over RDMA (SMC-R) and RoCE
 *
 *  CLC (connection layer control) handshake over initial TCP socket to
 *  prepare for RDMA traffic
 *
 *  Copyright IBM Corp. 2016, 2018
 *
 *  Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
 */

#include <linux/in.h>
#include <linux/inetdevice.h>
#include <linux/if_ether.h>
#include <linux/sched/signal.h>
#include <linux/utsname.h>
#include <linux/ctype.h>

#include <net/addrconf.h>
#include <net/sock.h>
#include <net/tcp.h>

#include "smc.h"
#include "smc_core.h"
#include "smc_clc.h"
#include "smc_ib.h"
#include "smc_ism.h"

#define SMCR_CLC_ACCEPT_CONFIRM_LEN 68
#define SMCD_CLC_ACCEPT_CONFIRM_LEN 48
#define SMCD_CLC_ACCEPT_CONFIRM_LEN_V2 78
#define SMC_CLC_RECV_BUF_LEN	100

/* eye catcher "SMCR" EBCDIC for CLC messages */
static const char SMC_EYECATCHER[4] = {'\xe2', '\xd4', '\xc3', '\xd9'};
/* eye catcher "SMCD" EBCDIC for CLC messages */
static const char SMCD_EYECATCHER[4] = {'\xe2', '\xd4', '\xc3', '\xc4'};

static u8 smc_hostname[SMC_MAX_HOSTNAME_LEN];

/* check arriving CLC proposal */
static bool smc_clc_msg_prop_valid(struct smc_clc_msg_proposal *pclc)
{
	struct smc_clc_msg_proposal_prefix *pclc_prfx;
	struct smc_clc_smcd_v2_extension *smcd_v2_ext;
	struct smc_clc_msg_hdr *hdr = &pclc->hdr;
	struct smc_clc_v2_extension *v2_ext;

	v2_ext = smc_get_clc_v2_ext(pclc);
	pclc_prfx = smc_clc_proposal_get_prefix(pclc);
	if (hdr->version == SMC_V1) {
		if (hdr->typev1 == SMC_TYPE_N)
			return false;
		if (ntohs(hdr->length) !=
			sizeof(*pclc) + ntohs(pclc->iparea_offset) +
			sizeof(*pclc_prfx) +
			pclc_prfx->ipv6_prefixes_cnt *
				sizeof(struct smc_clc_ipv6_prefix) +
			sizeof(struct smc_clc_msg_trail))
			return false;
	} else {
		if (ntohs(hdr->length) !=
			sizeof(*pclc) +
			sizeof(struct smc_clc_msg_smcd) +
			(hdr->typev1 != SMC_TYPE_N ?
				sizeof(*pclc_prfx) +
				pclc_prfx->ipv6_prefixes_cnt *
				sizeof(struct smc_clc_ipv6_prefix) : 0) +
			(hdr->typev2 != SMC_TYPE_N ?
				sizeof(*v2_ext) +
				v2_ext->hdr.eid_cnt * SMC_MAX_EID_LEN : 0) +
			(smcd_indicated(hdr->typev2) ?
				sizeof(*smcd_v2_ext) + v2_ext->hdr.ism_gid_cnt *
					sizeof(struct smc_clc_smcd_gid_chid) :
				0) +
			sizeof(struct smc_clc_msg_trail))
			return false;
	}
	return true;
}

/* check arriving CLC accept or confirm */
static bool
smc_clc_msg_acc_conf_valid(struct smc_clc_msg_accept_confirm_v2 *clc_v2)
{
	struct smc_clc_msg_hdr *hdr = &clc_v2->hdr;

	if (hdr->typev1 != SMC_TYPE_R && hdr->typev1 != SMC_TYPE_D)
		return false;
	if (hdr->version == SMC_V1) {
		if ((hdr->typev1 == SMC_TYPE_R &&
		     ntohs(hdr->length) != SMCR_CLC_ACCEPT_CONFIRM_LEN) ||
		    (hdr->typev1 == SMC_TYPE_D &&
		     ntohs(hdr->length) != SMCD_CLC_ACCEPT_CONFIRM_LEN))
			return false;
	} else {
		if (hdr->typev1 == SMC_TYPE_D &&
		    ntohs(hdr->length) != SMCD_CLC_ACCEPT_CONFIRM_LEN_V2 &&
		    (ntohs(hdr->length) != SMCD_CLC_ACCEPT_CONFIRM_LEN_V2 +
				sizeof(struct smc_clc_first_contact_ext)))
			return false;
	}
	return true;
}

static void smc_clc_fill_fce(struct smc_clc_first_contact_ext *fce, int *len)
{
	memset(fce, 0, sizeof(*fce));
	fce->os_type = SMC_CLC_OS_LINUX;
	fce->release = SMC_RELEASE;
	memcpy(fce->hostname, smc_hostname, sizeof(smc_hostname));
	(*len) += sizeof(*fce);
}

/* check if received message has a correct header length and contains valid
 * heading and trailing eyecatchers
 */
static bool smc_clc_msg_hdr_valid(struct smc_clc_msg_hdr *clcm, bool check_trl)
{
	struct smc_clc_msg_accept_confirm_v2 *clc_v2;
	struct smc_clc_msg_proposal *pclc;
	struct smc_clc_msg_decline *dclc;
	struct smc_clc_msg_trail *trl;

	if (memcmp(clcm->eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER)) &&
	    memcmp(clcm->eyecatcher, SMCD_EYECATCHER, sizeof(SMCD_EYECATCHER)))
		return false;
	switch (clcm->type) {
	case SMC_CLC_PROPOSAL:
		pclc = (struct smc_clc_msg_proposal *)clcm;
		if (!smc_clc_msg_prop_valid(pclc))
			return false;
		trl = (struct smc_clc_msg_trail *)
			((u8 *)pclc + ntohs(pclc->hdr.length) - sizeof(*trl));
		break;
	case SMC_CLC_ACCEPT:
	case SMC_CLC_CONFIRM:
		clc_v2 = (struct smc_clc_msg_accept_confirm_v2 *)clcm;
		if (!smc_clc_msg_acc_conf_valid(clc_v2))
			return false;
		trl = (struct smc_clc_msg_trail *)
			((u8 *)clc_v2 + ntohs(clc_v2->hdr.length) -
							sizeof(*trl));
		break;
	case SMC_CLC_DECLINE:
		dclc = (struct smc_clc_msg_decline *)clcm;
		if (ntohs(dclc->hdr.length) != sizeof(*dclc))
			return false;
		trl = &dclc->trl;
		break;
	default:
		return false;
	}
	if (check_trl &&
	    memcmp(trl->eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER)) &&
	    memcmp(trl->eyecatcher, SMCD_EYECATCHER, sizeof(SMCD_EYECATCHER)))
		return false;
	return true;
}

/* find ipv4 addr on device and get the prefix len, fill CLC proposal msg */
static int smc_clc_prfx_set4_rcu(struct dst_entry *dst, __be32 ipv4,
				 struct smc_clc_msg_proposal_prefix *prop)
{
	struct in_device *in_dev = __in_dev_get_rcu(dst->dev);
	const struct in_ifaddr *ifa;

	if (!in_dev)
		return -ENODEV;

	in_dev_for_each_ifa_rcu(ifa, in_dev) {
		if (!inet_ifa_match(ipv4, ifa))
			continue;
		prop->prefix_len = inet_mask_len(ifa->ifa_mask);
		prop->outgoing_subnet = ifa->ifa_address & ifa->ifa_mask;
		/* prop->ipv6_prefixes_cnt = 0; already done by memset before */
		return 0;
	}
	return -ENOENT;
}

/* fill CLC proposal msg with ipv6 prefixes from device */
static int smc_clc_prfx_set6_rcu(struct dst_entry *dst,
				 struct smc_clc_msg_proposal_prefix *prop,
				 struct smc_clc_ipv6_prefix *ipv6_prfx)
{
#if IS_ENABLED(CONFIG_IPV6)
	struct inet6_dev *in6_dev = __in6_dev_get(dst->dev);
	struct inet6_ifaddr *ifa;
	int cnt = 0;

	if (!in6_dev)
		return -ENODEV;
	/* use a maximum of 8 IPv6 prefixes from device */
	list_for_each_entry(ifa, &in6_dev->addr_list, if_list) {
		if (ipv6_addr_type(&ifa->addr) & IPV6_ADDR_LINKLOCAL)
			continue;
		ipv6_addr_prefix(&ipv6_prfx[cnt].prefix,
				 &ifa->addr, ifa->prefix_len);
		ipv6_prfx[cnt].prefix_len = ifa->prefix_len;
		cnt++;
		if (cnt == SMC_CLC_MAX_V6_PREFIX)
			break;
	}
	prop->ipv6_prefixes_cnt = cnt;
	if (cnt)
		return 0;
#endif
	return -ENOENT;
}

/* retrieve and set prefixes in CLC proposal msg */
static int smc_clc_prfx_set(struct socket *clcsock,
			    struct smc_clc_msg_proposal_prefix *prop,
			    struct smc_clc_ipv6_prefix *ipv6_prfx)
{
	struct dst_entry *dst = sk_dst_get(clcsock->sk);
	struct sockaddr_storage addrs;
	struct sockaddr_in6 *addr6;
	struct sockaddr_in *addr;
	int rc = -ENOENT;

	if (!dst) {
		rc = -ENOTCONN;
		goto out;
	}
	if (!dst->dev) {
		rc = -ENODEV;
		goto out_rel;
	}
	/* get address to which the internal TCP socket is bound */
	if (kernel_getsockname(clcsock, (struct sockaddr *)&addrs) < 0)
		goto out_rel;
	/* analyze IP specific data of net_device belonging to TCP socket */
	addr6 = (struct sockaddr_in6 *)&addrs;
	rcu_read_lock();
	if (addrs.ss_family == PF_INET) {
		/* IPv4 */
		addr = (struct sockaddr_in *)&addrs;
		rc = smc_clc_prfx_set4_rcu(dst, addr->sin_addr.s_addr, prop);
	} else if (ipv6_addr_v4mapped(&addr6->sin6_addr)) {
		/* mapped IPv4 address - peer is IPv4 only */
		rc = smc_clc_prfx_set4_rcu(dst, addr6->sin6_addr.s6_addr32[3],
					   prop);
	} else {
		/* IPv6 */
		rc = smc_clc_prfx_set6_rcu(dst, prop, ipv6_prfx);
	}
	rcu_read_unlock();
out_rel:
	dst_release(dst);
out:
	return rc;
}

/* match ipv4 addrs of dev against addr in CLC proposal */
static int smc_clc_prfx_match4_rcu(struct net_device *dev,
				   struct smc_clc_msg_proposal_prefix *prop)
{
	struct in_device *in_dev = __in_dev_get_rcu(dev);
	const struct in_ifaddr *ifa;

	if (!in_dev)
		return -ENODEV;
	in_dev_for_each_ifa_rcu(ifa, in_dev) {
		if (prop->prefix_len == inet_mask_len(ifa->ifa_mask) &&
		    inet_ifa_match(prop->outgoing_subnet, ifa))
			return 0;
	}

	return -ENOENT;
}

/* match ipv6 addrs of dev against addrs in CLC proposal */
static int smc_clc_prfx_match6_rcu(struct net_device *dev,
				   struct smc_clc_msg_proposal_prefix *prop)
{
#if IS_ENABLED(CONFIG_IPV6)
	struct inet6_dev *in6_dev = __in6_dev_get(dev);
	struct smc_clc_ipv6_prefix *ipv6_prfx;
	struct inet6_ifaddr *ifa;
	int i, max;

	if (!in6_dev)
		return -ENODEV;
	/* ipv6 prefix list starts behind smc_clc_msg_proposal_prefix */
	ipv6_prfx = (struct smc_clc_ipv6_prefix *)((u8 *)prop + sizeof(*prop));
	max = min_t(u8, prop->ipv6_prefixes_cnt, SMC_CLC_MAX_V6_PREFIX);
	list_for_each_entry(ifa, &in6_dev->addr_list, if_list) {
		if (ipv6_addr_type(&ifa->addr) & IPV6_ADDR_LINKLOCAL)
			continue;
		for (i = 0; i < max; i++) {
			if (ifa->prefix_len == ipv6_prfx[i].prefix_len &&
			    ipv6_prefix_equal(&ifa->addr, &ipv6_prfx[i].prefix,
					      ifa->prefix_len))
				return 0;
		}
	}
#endif
	return -ENOENT;
}

/* check if proposed prefixes match one of our device prefixes */
int smc_clc_prfx_match(struct socket *clcsock,
		       struct smc_clc_msg_proposal_prefix *prop)
{
	struct dst_entry *dst = sk_dst_get(clcsock->sk);
	int rc;

	if (!dst) {
		rc = -ENOTCONN;
		goto out;
	}
	if (!dst->dev) {
		rc = -ENODEV;
		goto out_rel;
	}
	rcu_read_lock();
	if (!prop->ipv6_prefixes_cnt)
		rc = smc_clc_prfx_match4_rcu(dst->dev, prop);
	else
		rc = smc_clc_prfx_match6_rcu(dst->dev, prop);
	rcu_read_unlock();
out_rel:
	dst_release(dst);
out:
	return rc;
}

/* Wait for data on the tcp-socket, analyze received data
 * Returns:
 * 0 if success and it was not a decline that we received.
 * SMC_CLC_DECL_REPLY if decline received for fallback w/o another decl send.
 * clcsock error, -EINTR, -ECONNRESET, -EPROTO otherwise.
 */
int smc_clc_wait_msg(struct smc_sock *smc, void *buf, int buflen,
		     u8 expected_type, unsigned long timeout)
{
	long rcvtimeo = smc->clcsock->sk->sk_rcvtimeo;
	struct sock *clc_sk = smc->clcsock->sk;
	struct smc_clc_msg_hdr *clcm = buf;
	struct msghdr msg = {NULL, 0};
	int reason_code = 0;
	struct kvec vec = {buf, buflen};
	int len, datlen, recvlen;
	bool check_trl = true;
	int krflags;

	/* peek the first few bytes to determine length of data to receive
	 * so we don't consume any subsequent CLC message or payload data
	 * in the TCP byte stream
	 */
	/*
	 * Caller must make sure that buflen is no less than
	 * sizeof(struct smc_clc_msg_hdr)
	 */
	krflags = MSG_PEEK | MSG_WAITALL;
	clc_sk->sk_rcvtimeo = timeout;
	iov_iter_kvec(&msg.msg_iter, READ, &vec, 1,
			sizeof(struct smc_clc_msg_hdr));
	len = sock_recvmsg(smc->clcsock, &msg, krflags);
	if (signal_pending(current)) {
		reason_code = -EINTR;
		clc_sk->sk_err = EINTR;
		smc->sk.sk_err = EINTR;
		goto out;
	}
	if (clc_sk->sk_err) {
		reason_code = -clc_sk->sk_err;
		if (clc_sk->sk_err == EAGAIN &&
		    expected_type == SMC_CLC_DECLINE)
			clc_sk->sk_err = 0; /* reset for fallback usage */
		else
			smc->sk.sk_err = clc_sk->sk_err;
		goto out;
	}
	if (!len) { /* peer has performed orderly shutdown */
		smc->sk.sk_err = ECONNRESET;
		reason_code = -ECONNRESET;
		goto out;
	}
	if (len < 0) {
		if (len != -EAGAIN || expected_type != SMC_CLC_DECLINE)
			smc->sk.sk_err = -len;
		reason_code = len;
		goto out;
	}
	datlen = ntohs(clcm->length);
	if ((len < sizeof(struct smc_clc_msg_hdr)) ||
	    (clcm->version < SMC_V1) ||
	    ((clcm->type != SMC_CLC_DECLINE) &&
	     (clcm->type != expected_type))) {
		smc->sk.sk_err = EPROTO;
		reason_code = -EPROTO;
		goto out;
	}

	/* receive the complete CLC message */
	memset(&msg, 0, sizeof(struct msghdr));
	if (datlen > buflen) {
		check_trl = false;
		recvlen = buflen;
	} else {
		recvlen = datlen;
	}
	iov_iter_kvec(&msg.msg_iter, READ, &vec, 1, recvlen);
	krflags = MSG_WAITALL;
	len = sock_recvmsg(smc->clcsock, &msg, krflags);
	if (len < recvlen || !smc_clc_msg_hdr_valid(clcm, check_trl)) {
		smc->sk.sk_err = EPROTO;
		reason_code = -EPROTO;
		goto out;
	}
	datlen -= len;
	while (datlen) {
		u8 tmp[SMC_CLC_RECV_BUF_LEN];

		vec.iov_base = &tmp;
		vec.iov_len = SMC_CLC_RECV_BUF_LEN;
		/* receive remaining proposal message */
		recvlen = datlen > SMC_CLC_RECV_BUF_LEN ?
						SMC_CLC_RECV_BUF_LEN : datlen;
		iov_iter_kvec(&msg.msg_iter, READ, &vec, 1, recvlen);
		len = sock_recvmsg(smc->clcsock, &msg, krflags);
		datlen -= len;
	}
	if (clcm->type == SMC_CLC_DECLINE) {
		struct smc_clc_msg_decline *dclc;

		dclc = (struct smc_clc_msg_decline *)clcm;
		reason_code = SMC_CLC_DECL_PEERDECL;
		smc->peer_diagnosis = ntohl(dclc->peer_diagnosis);
		if (((struct smc_clc_msg_decline *)buf)->hdr.typev2 &
						SMC_FIRST_CONTACT_MASK) {
			smc->conn.lgr->sync_err = 1;
			smc_lgr_terminate_sched(smc->conn.lgr);
		}
	}

out:
	clc_sk->sk_rcvtimeo = rcvtimeo;
	return reason_code;
}

/* send CLC DECLINE message across internal TCP socket */
int smc_clc_send_decline(struct smc_sock *smc, u32 peer_diag_info, u8 version)
{
	struct smc_clc_msg_decline dclc;
	struct msghdr msg;
	struct kvec vec;
	int len;

	memset(&dclc, 0, sizeof(dclc));
	memcpy(dclc.hdr.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
	dclc.hdr.type = SMC_CLC_DECLINE;
	dclc.hdr.length = htons(sizeof(struct smc_clc_msg_decline));
	dclc.hdr.version = version;
	dclc.os_type = version == SMC_V1 ? 0 : SMC_CLC_OS_LINUX;
	dclc.hdr.typev2 = (peer_diag_info == SMC_CLC_DECL_SYNCERR) ?
						SMC_FIRST_CONTACT_MASK : 0;
	if ((!smc->conn.lgr || !smc->conn.lgr->is_smcd) &&
	    smc_ib_is_valid_local_systemid())
		memcpy(dclc.id_for_peer, local_systemid,
		       sizeof(local_systemid));
	dclc.peer_diagnosis = htonl(peer_diag_info);
	memcpy(dclc.trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));

	memset(&msg, 0, sizeof(msg));
	vec.iov_base = &dclc;
	vec.iov_len = sizeof(struct smc_clc_msg_decline);
	len = kernel_sendmsg(smc->clcsock, &msg, &vec, 1,
			     sizeof(struct smc_clc_msg_decline));
	if (len < 0 || len < sizeof(struct smc_clc_msg_decline))
		len = -EPROTO;
	return len > 0 ? 0 : len;
}

/* send CLC PROPOSAL message across internal TCP socket */
int smc_clc_send_proposal(struct smc_sock *smc, struct smc_init_info *ini)
{
	struct smc_clc_smcd_v2_extension *smcd_v2_ext;
	struct smc_clc_msg_proposal_prefix *pclc_prfx;
	struct smc_clc_msg_proposal *pclc_base;
	struct smc_clc_smcd_gid_chid *gidchids;
	struct smc_clc_msg_proposal_area *pclc;
	struct smc_clc_ipv6_prefix *ipv6_prfx;
	struct smc_clc_v2_extension *v2_ext;
	struct smc_clc_msg_smcd *pclc_smcd;
	struct smc_clc_msg_trail *trl;
	int len, i, plen, rc;
	int reason_code = 0;
	struct kvec vec[8];
	struct msghdr msg;

	pclc = kzalloc(sizeof(*pclc), GFP_KERNEL);
	if (!pclc)
		return -ENOMEM;

	pclc_base = &pclc->pclc_base;
	pclc_smcd = &pclc->pclc_smcd;
	pclc_prfx = &pclc->pclc_prfx;
	ipv6_prfx = pclc->pclc_prfx_ipv6;
	v2_ext = &pclc->pclc_v2_ext;
	smcd_v2_ext = &pclc->pclc_smcd_v2_ext;
	gidchids = pclc->pclc_gidchids;
	trl = &pclc->pclc_trl;

	pclc_base->hdr.version = SMC_V2;
	pclc_base->hdr.typev1 = ini->smc_type_v1;
	pclc_base->hdr.typev2 = ini->smc_type_v2;
	plen = sizeof(*pclc_base) + sizeof(*pclc_smcd) + sizeof(*trl);

	/* retrieve ip prefixes for CLC proposal msg */
	if (ini->smc_type_v1 != SMC_TYPE_N) {
		rc = smc_clc_prfx_set(smc->clcsock, pclc_prfx, ipv6_prfx);
		if (rc) {
			if (ini->smc_type_v2 == SMC_TYPE_N) {
				kfree(pclc);
				return SMC_CLC_DECL_CNFERR;
			}
			pclc_base->hdr.typev1 = SMC_TYPE_N;
		} else {
			pclc_base->iparea_offset = htons(sizeof(*pclc_smcd));
			plen += sizeof(*pclc_prfx) +
					pclc_prfx->ipv6_prefixes_cnt *
					sizeof(ipv6_prfx[0]);
		}
	}

	/* build SMC Proposal CLC message */
	memcpy(pclc_base->hdr.eyecatcher, SMC_EYECATCHER,
	       sizeof(SMC_EYECATCHER));
	pclc_base->hdr.type = SMC_CLC_PROPOSAL;
	if (smcr_indicated(ini->smc_type_v1)) {
		/* add SMC-R specifics */
		memcpy(pclc_base->lcl.id_for_peer, local_systemid,
		       sizeof(local_systemid));
		memcpy(pclc_base->lcl.gid, ini->ib_gid, SMC_GID_SIZE);
		memcpy(pclc_base->lcl.mac, &ini->ib_dev->mac[ini->ib_port - 1],
		       ETH_ALEN);
	}
	if (smcd_indicated(ini->smc_type_v1)) {
		/* add SMC-D specifics */
		if (ini->ism_dev[0]) {
			pclc_smcd->ism.gid = htonll(ini->ism_dev[0]->local_gid);
			pclc_smcd->ism.chid =
				htons(smc_ism_get_chid(ini->ism_dev[0]));
		}
	}
	if (ini->smc_type_v2 == SMC_TYPE_N) {
		pclc_smcd->v2_ext_offset = 0;
	} else {
		u16 v2_ext_offset;
		u8 *eid = NULL;

		v2_ext_offset = sizeof(*pclc_smcd) -
			offsetofend(struct smc_clc_msg_smcd, v2_ext_offset);
		if (ini->smc_type_v1 != SMC_TYPE_N)
			v2_ext_offset += sizeof(*pclc_prfx) +
						pclc_prfx->ipv6_prefixes_cnt *
						sizeof(ipv6_prfx[0]);
		pclc_smcd->v2_ext_offset = htons(v2_ext_offset);
		v2_ext->hdr.eid_cnt = 0;
		v2_ext->hdr.ism_gid_cnt = ini->ism_offered_cnt;
		v2_ext->hdr.flag.release = SMC_RELEASE;
		v2_ext->hdr.flag.seid = 1;
		v2_ext->hdr.smcd_v2_ext_offset = htons(sizeof(*v2_ext) -
				offsetofend(struct smc_clnt_opts_area_hdr,
					    smcd_v2_ext_offset) +
				v2_ext->hdr.eid_cnt * SMC_MAX_EID_LEN);
		if (ini->ism_dev[0])
			smc_ism_get_system_eid(ini->ism_dev[0], &eid);
		else
			smc_ism_get_system_eid(ini->ism_dev[1], &eid);
		if (eid)
			memcpy(smcd_v2_ext->system_eid, eid, SMC_MAX_EID_LEN);
		plen += sizeof(*v2_ext) + sizeof(*smcd_v2_ext);
		if (ini->ism_offered_cnt) {
			for (i = 1; i <= ini->ism_offered_cnt; i++) {
				gidchids[i - 1].gid =
					htonll(ini->ism_dev[i]->local_gid);
				gidchids[i - 1].chid =
					htons(smc_ism_get_chid(ini->ism_dev[i]));
			}
			plen += ini->ism_offered_cnt *
				sizeof(struct smc_clc_smcd_gid_chid);
		}
	}
	pclc_base->hdr.length = htons(plen);
	memcpy(trl->eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));

	/* send SMC Proposal CLC message */
	memset(&msg, 0, sizeof(msg));
	i = 0;
	vec[i].iov_base = pclc_base;
	vec[i++].iov_len = sizeof(*pclc_base);
	vec[i].iov_base = pclc_smcd;
	vec[i++].iov_len = sizeof(*pclc_smcd);
	if (ini->smc_type_v1 != SMC_TYPE_N) {
		vec[i].iov_base = pclc_prfx;
		vec[i++].iov_len = sizeof(*pclc_prfx);
		if (pclc_prfx->ipv6_prefixes_cnt > 0) {
			vec[i].iov_base = ipv6_prfx;
			vec[i++].iov_len = pclc_prfx->ipv6_prefixes_cnt *
					   sizeof(ipv6_prfx[0]);
		}
	}
	if (ini->smc_type_v2 != SMC_TYPE_N) {
		vec[i].iov_base = v2_ext;
		vec[i++].iov_len = sizeof(*v2_ext);
		vec[i].iov_base = smcd_v2_ext;
		vec[i++].iov_len = sizeof(*smcd_v2_ext);
		if (ini->ism_offered_cnt) {
			vec[i].iov_base = gidchids;
			vec[i++].iov_len = ini->ism_offered_cnt *
					sizeof(struct smc_clc_smcd_gid_chid);
		}
	}
	vec[i].iov_base = trl;
	vec[i++].iov_len = sizeof(*trl);
	/* due to the few bytes needed for clc-handshake this cannot block */
	len = kernel_sendmsg(smc->clcsock, &msg, vec, i, plen);
	if (len < 0) {
		smc->sk.sk_err = smc->clcsock->sk->sk_err;
		reason_code = -smc->sk.sk_err;
	} else if (len < ntohs(pclc_base->hdr.length)) {
		reason_code = -ENETUNREACH;
		smc->sk.sk_err = -reason_code;
	}

	kfree(pclc);
	return reason_code;
}

/* build and send CLC CONFIRM / ACCEPT message */
static int smc_clc_send_confirm_accept(struct smc_sock *smc,
				       struct smc_clc_msg_accept_confirm_v2 *clc_v2,
				       int first_contact, u8 version)
{
	struct smc_connection *conn = &smc->conn;
	struct smc_clc_msg_accept_confirm *clc;
	struct smc_clc_first_contact_ext fce;
	struct smc_clc_msg_trail trl;
	struct kvec vec[3];
	struct msghdr msg;
	int i, len;

	/* send SMC Confirm CLC msg */
	clc = (struct smc_clc_msg_accept_confirm *)clc_v2;
	clc->hdr.version = version;	/* SMC version */
	if (first_contact)
		clc->hdr.typev2 |= SMC_FIRST_CONTACT_MASK;
	if (conn->lgr->is_smcd) {
		/* SMC-D specific settings */
		memcpy(clc->hdr.eyecatcher, SMCD_EYECATCHER,
		       sizeof(SMCD_EYECATCHER));
		clc->hdr.typev1 = SMC_TYPE_D;
		clc->d0.gid = conn->lgr->smcd->local_gid;
		clc->d0.token = conn->rmb_desc->token;
		clc->d0.dmbe_size = conn->rmbe_size_short;
		clc->d0.dmbe_idx = 0;
		memcpy(&clc->d0.linkid, conn->lgr->id, SMC_LGR_ID_SIZE);
		if (version == SMC_V1) {
			clc->hdr.length = htons(SMCD_CLC_ACCEPT_CONFIRM_LEN);
		} else {
			u8 *eid = NULL;

			clc_v2->chid = htons(smc_ism_get_chid(conn->lgr->smcd));
			smc_ism_get_system_eid(conn->lgr->smcd, &eid);
			if (eid)
				memcpy(clc_v2->eid, eid, SMC_MAX_EID_LEN);
			len = SMCD_CLC_ACCEPT_CONFIRM_LEN_V2;
			if (first_contact)
				smc_clc_fill_fce(&fce, &len);
			clc_v2->hdr.length = htons(len);
		}
		memcpy(trl.eyecatcher, SMCD_EYECATCHER,
		       sizeof(SMCD_EYECATCHER));
	} else {
		struct smc_link *link = conn->lnk;

		/* SMC-R specific settings */
		link = conn->lnk;
		memcpy(clc->hdr.eyecatcher, SMC_EYECATCHER,
		       sizeof(SMC_EYECATCHER));
		clc->hdr.typev1 = SMC_TYPE_R;
		clc->hdr.length = htons(SMCR_CLC_ACCEPT_CONFIRM_LEN);
		memcpy(clc->r0.lcl.id_for_peer, local_systemid,
		       sizeof(local_systemid));
		memcpy(&clc->r0.lcl.gid, link->gid, SMC_GID_SIZE);
		memcpy(&clc->r0.lcl.mac, &link->smcibdev->mac[link->ibport - 1],
		       ETH_ALEN);
		hton24(clc->r0.qpn, link->roce_qp->qp_num);
		clc->r0.rmb_rkey =
			htonl(conn->rmb_desc->mr_rx[link->link_idx]->rkey);
		clc->r0.rmbe_idx = 1; /* for now: 1 RMB = 1 RMBE */
		clc->r0.rmbe_alert_token = htonl(conn->alert_token_local);
		switch (clc->hdr.type) {
		case SMC_CLC_ACCEPT:
			clc->r0.qp_mtu = link->path_mtu;
			break;
		case SMC_CLC_CONFIRM:
			clc->r0.qp_mtu = min(link->path_mtu, link->peer_mtu);
			break;
		}
		clc->r0.rmbe_size = conn->rmbe_size_short;
		clc->r0.rmb_dma_addr = cpu_to_be64((u64)sg_dma_address
				(conn->rmb_desc->sgt[link->link_idx].sgl));
		hton24(clc->r0.psn, link->psn_initial);
		memcpy(trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
	}

	memset(&msg, 0, sizeof(msg));
	i = 0;
	vec[i].iov_base = clc_v2;
	if (version > SMC_V1)
		vec[i++].iov_len = SMCD_CLC_ACCEPT_CONFIRM_LEN_V2 - sizeof(trl);
	else
		vec[i++].iov_len = (clc->hdr.typev1 == SMC_TYPE_D ?
						SMCD_CLC_ACCEPT_CONFIRM_LEN :
						SMCR_CLC_ACCEPT_CONFIRM_LEN) -
				   sizeof(trl);
	if (version > SMC_V1 && first_contact) {
		vec[i].iov_base = &fce;
		vec[i++].iov_len = sizeof(fce);
	}
	vec[i].iov_base = &trl;
	vec[i++].iov_len = sizeof(trl);
	return kernel_sendmsg(smc->clcsock, &msg, vec, 1,
			      ntohs(clc->hdr.length));
}

/* send CLC CONFIRM message across internal TCP socket */
int smc_clc_send_confirm(struct smc_sock *smc, bool clnt_first_contact,
			 u8 version)
{
	struct smc_clc_msg_accept_confirm_v2 cclc_v2;
	int reason_code = 0;
	int len;

	/* send SMC Confirm CLC msg */
	memset(&cclc_v2, 0, sizeof(cclc_v2));
	cclc_v2.hdr.type = SMC_CLC_CONFIRM;
	len = smc_clc_send_confirm_accept(smc, &cclc_v2, clnt_first_contact,
					  version);
	if (len < ntohs(cclc_v2.hdr.length)) {
		if (len >= 0) {
			reason_code = -ENETUNREACH;
			smc->sk.sk_err = -reason_code;
		} else {
			smc->sk.sk_err = smc->clcsock->sk->sk_err;
			reason_code = -smc->sk.sk_err;
		}
	}
	return reason_code;
}

/* send CLC ACCEPT message across internal TCP socket */
int smc_clc_send_accept(struct smc_sock *new_smc, bool srv_first_contact,
			u8 version)
{
	struct smc_clc_msg_accept_confirm_v2 aclc_v2;
	int len;

	memset(&aclc_v2, 0, sizeof(aclc_v2));
	aclc_v2.hdr.type = SMC_CLC_ACCEPT;
	len = smc_clc_send_confirm_accept(new_smc, &aclc_v2, srv_first_contact,
					  version);
	if (len < ntohs(aclc_v2.hdr.length))
		len = len >= 0 ? -EPROTO : -new_smc->clcsock->sk->sk_err;

	return len > 0 ? 0 : len;
}

void smc_clc_get_hostname(u8 **host)
{
	*host = &smc_hostname[0];
}

void __init smc_clc_init(void)
{
	struct new_utsname *u;

	memset(smc_hostname, _S, sizeof(smc_hostname)); /* ASCII blanks */
	u = utsname();
	memcpy(smc_hostname, u->nodename,
	       min_t(size_t, strlen(u->nodename), sizeof(smc_hostname)));
}