xref: /openbmc/linux/net/smc/smc_clc.c (revision 59bd9ded)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  Shared Memory Communications over RDMA (SMC-R) and RoCE
4  *
5  *  CLC (connection layer control) handshake over initial TCP socket to
6  *  prepare for RDMA traffic
7  *
8  *  Copyright IBM Corp. 2016, 2018
9  *
10  *  Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
11  */
12 
13 #include <linux/in.h>
14 #include <linux/inetdevice.h>
15 #include <linux/if_ether.h>
16 #include <linux/sched/signal.h>
17 
18 #include <net/addrconf.h>
19 #include <net/sock.h>
20 #include <net/tcp.h>
21 
22 #include "smc.h"
23 #include "smc_core.h"
24 #include "smc_clc.h"
25 #include "smc_ib.h"
26 #include "smc_ism.h"
27 
28 #define SMCR_CLC_ACCEPT_CONFIRM_LEN 68
29 #define SMCD_CLC_ACCEPT_CONFIRM_LEN 48
30 
31 /* eye catcher "SMCR" EBCDIC for CLC messages */
32 static const char SMC_EYECATCHER[4] = {'\xe2', '\xd4', '\xc3', '\xd9'};
33 /* eye catcher "SMCD" EBCDIC for CLC messages */
34 static const char SMCD_EYECATCHER[4] = {'\xe2', '\xd4', '\xc3', '\xc4'};
35 
36 /* check if received message has a correct header length and contains valid
37  * heading and trailing eyecatchers
38  */
39 static bool smc_clc_msg_hdr_valid(struct smc_clc_msg_hdr *clcm)
40 {
41 	struct smc_clc_msg_proposal_prefix *pclc_prfx;
42 	struct smc_clc_msg_accept_confirm *clc;
43 	struct smc_clc_msg_proposal *pclc;
44 	struct smc_clc_msg_decline *dclc;
45 	struct smc_clc_msg_trail *trl;
46 
47 	if (memcmp(clcm->eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER)) &&
48 	    memcmp(clcm->eyecatcher, SMCD_EYECATCHER, sizeof(SMCD_EYECATCHER)))
49 		return false;
50 	switch (clcm->type) {
51 	case SMC_CLC_PROPOSAL:
52 		if (clcm->path != SMC_TYPE_R && clcm->path != SMC_TYPE_D &&
53 		    clcm->path != SMC_TYPE_B)
54 			return false;
55 		pclc = (struct smc_clc_msg_proposal *)clcm;
56 		pclc_prfx = smc_clc_proposal_get_prefix(pclc);
57 		if (ntohs(pclc->hdr.length) !=
58 			sizeof(*pclc) + ntohs(pclc->iparea_offset) +
59 			sizeof(*pclc_prfx) +
60 			pclc_prfx->ipv6_prefixes_cnt *
61 				sizeof(struct smc_clc_ipv6_prefix) +
62 			sizeof(*trl))
63 			return false;
64 		trl = (struct smc_clc_msg_trail *)
65 			((u8 *)pclc + ntohs(pclc->hdr.length) - sizeof(*trl));
66 		break;
67 	case SMC_CLC_ACCEPT:
68 	case SMC_CLC_CONFIRM:
69 		if (clcm->path != SMC_TYPE_R && clcm->path != SMC_TYPE_D)
70 			return false;
71 		clc = (struct smc_clc_msg_accept_confirm *)clcm;
72 		if ((clcm->path == SMC_TYPE_R &&
73 		     ntohs(clc->hdr.length) != SMCR_CLC_ACCEPT_CONFIRM_LEN) ||
74 		    (clcm->path == SMC_TYPE_D &&
75 		     ntohs(clc->hdr.length) != SMCD_CLC_ACCEPT_CONFIRM_LEN))
76 			return false;
77 		trl = (struct smc_clc_msg_trail *)
78 			((u8 *)clc + ntohs(clc->hdr.length) - sizeof(*trl));
79 		break;
80 	case SMC_CLC_DECLINE:
81 		dclc = (struct smc_clc_msg_decline *)clcm;
82 		if (ntohs(dclc->hdr.length) != sizeof(*dclc))
83 			return false;
84 		trl = &dclc->trl;
85 		break;
86 	default:
87 		return false;
88 	}
89 	if (memcmp(trl->eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER)) &&
90 	    memcmp(trl->eyecatcher, SMCD_EYECATCHER, sizeof(SMCD_EYECATCHER)))
91 		return false;
92 	return true;
93 }
94 
95 /* find ipv4 addr on device and get the prefix len, fill CLC proposal msg */
96 static int smc_clc_prfx_set4_rcu(struct dst_entry *dst, __be32 ipv4,
97 				 struct smc_clc_msg_proposal_prefix *prop)
98 {
99 	struct in_device *in_dev = __in_dev_get_rcu(dst->dev);
100 
101 	if (!in_dev)
102 		return -ENODEV;
103 	for_ifa(in_dev) {
104 		if (!inet_ifa_match(ipv4, ifa))
105 			continue;
106 		prop->prefix_len = inet_mask_len(ifa->ifa_mask);
107 		prop->outgoing_subnet = ifa->ifa_address & ifa->ifa_mask;
108 		/* prop->ipv6_prefixes_cnt = 0; already done by memset before */
109 		return 0;
110 	} endfor_ifa(in_dev);
111 	return -ENOENT;
112 }
113 
114 /* fill CLC proposal msg with ipv6 prefixes from device */
115 static int smc_clc_prfx_set6_rcu(struct dst_entry *dst,
116 				 struct smc_clc_msg_proposal_prefix *prop,
117 				 struct smc_clc_ipv6_prefix *ipv6_prfx)
118 {
119 #if IS_ENABLED(CONFIG_IPV6)
120 	struct inet6_dev *in6_dev = __in6_dev_get(dst->dev);
121 	struct inet6_ifaddr *ifa;
122 	int cnt = 0;
123 
124 	if (!in6_dev)
125 		return -ENODEV;
126 	/* use a maximum of 8 IPv6 prefixes from device */
127 	list_for_each_entry(ifa, &in6_dev->addr_list, if_list) {
128 		if (ipv6_addr_type(&ifa->addr) & IPV6_ADDR_LINKLOCAL)
129 			continue;
130 		ipv6_addr_prefix(&ipv6_prfx[cnt].prefix,
131 				 &ifa->addr, ifa->prefix_len);
132 		ipv6_prfx[cnt].prefix_len = ifa->prefix_len;
133 		cnt++;
134 		if (cnt == SMC_CLC_MAX_V6_PREFIX)
135 			break;
136 	}
137 	prop->ipv6_prefixes_cnt = cnt;
138 	if (cnt)
139 		return 0;
140 #endif
141 	return -ENOENT;
142 }
143 
144 /* retrieve and set prefixes in CLC proposal msg */
145 static int smc_clc_prfx_set(struct socket *clcsock,
146 			    struct smc_clc_msg_proposal_prefix *prop,
147 			    struct smc_clc_ipv6_prefix *ipv6_prfx)
148 {
149 	struct dst_entry *dst = sk_dst_get(clcsock->sk);
150 	struct sockaddr_storage addrs;
151 	struct sockaddr_in6 *addr6;
152 	struct sockaddr_in *addr;
153 	int rc = -ENOENT;
154 
155 	memset(prop, 0, sizeof(*prop));
156 	if (!dst) {
157 		rc = -ENOTCONN;
158 		goto out;
159 	}
160 	if (!dst->dev) {
161 		rc = -ENODEV;
162 		goto out_rel;
163 	}
164 	/* get address to which the internal TCP socket is bound */
165 	kernel_getsockname(clcsock, (struct sockaddr *)&addrs);
166 	/* analyze IP specific data of net_device belonging to TCP socket */
167 	addr6 = (struct sockaddr_in6 *)&addrs;
168 	rcu_read_lock();
169 	if (addrs.ss_family == PF_INET) {
170 		/* IPv4 */
171 		addr = (struct sockaddr_in *)&addrs;
172 		rc = smc_clc_prfx_set4_rcu(dst, addr->sin_addr.s_addr, prop);
173 	} else if (ipv6_addr_v4mapped(&addr6->sin6_addr)) {
174 		/* mapped IPv4 address - peer is IPv4 only */
175 		rc = smc_clc_prfx_set4_rcu(dst, addr6->sin6_addr.s6_addr32[3],
176 					   prop);
177 	} else {
178 		/* IPv6 */
179 		rc = smc_clc_prfx_set6_rcu(dst, prop, ipv6_prfx);
180 	}
181 	rcu_read_unlock();
182 out_rel:
183 	dst_release(dst);
184 out:
185 	return rc;
186 }
187 
188 /* match ipv4 addrs of dev against addr in CLC proposal */
189 static int smc_clc_prfx_match4_rcu(struct net_device *dev,
190 				   struct smc_clc_msg_proposal_prefix *prop)
191 {
192 	struct in_device *in_dev = __in_dev_get_rcu(dev);
193 
194 	if (!in_dev)
195 		return -ENODEV;
196 	for_ifa(in_dev) {
197 		if (prop->prefix_len == inet_mask_len(ifa->ifa_mask) &&
198 		    inet_ifa_match(prop->outgoing_subnet, ifa))
199 			return 0;
200 	} endfor_ifa(in_dev);
201 
202 	return -ENOENT;
203 }
204 
205 /* match ipv6 addrs of dev against addrs in CLC proposal */
206 static int smc_clc_prfx_match6_rcu(struct net_device *dev,
207 				   struct smc_clc_msg_proposal_prefix *prop)
208 {
209 #if IS_ENABLED(CONFIG_IPV6)
210 	struct inet6_dev *in6_dev = __in6_dev_get(dev);
211 	struct smc_clc_ipv6_prefix *ipv6_prfx;
212 	struct inet6_ifaddr *ifa;
213 	int i, max;
214 
215 	if (!in6_dev)
216 		return -ENODEV;
217 	/* ipv6 prefix list starts behind smc_clc_msg_proposal_prefix */
218 	ipv6_prfx = (struct smc_clc_ipv6_prefix *)((u8 *)prop + sizeof(*prop));
219 	max = min_t(u8, prop->ipv6_prefixes_cnt, SMC_CLC_MAX_V6_PREFIX);
220 	list_for_each_entry(ifa, &in6_dev->addr_list, if_list) {
221 		if (ipv6_addr_type(&ifa->addr) & IPV6_ADDR_LINKLOCAL)
222 			continue;
223 		for (i = 0; i < max; i++) {
224 			if (ifa->prefix_len == ipv6_prfx[i].prefix_len &&
225 			    ipv6_prefix_equal(&ifa->addr, &ipv6_prfx[i].prefix,
226 					      ifa->prefix_len))
227 				return 0;
228 		}
229 	}
230 #endif
231 	return -ENOENT;
232 }
233 
234 /* check if proposed prefixes match one of our device prefixes */
235 int smc_clc_prfx_match(struct socket *clcsock,
236 		       struct smc_clc_msg_proposal_prefix *prop)
237 {
238 	struct dst_entry *dst = sk_dst_get(clcsock->sk);
239 	int rc;
240 
241 	if (!dst) {
242 		rc = -ENOTCONN;
243 		goto out;
244 	}
245 	if (!dst->dev) {
246 		rc = -ENODEV;
247 		goto out_rel;
248 	}
249 	rcu_read_lock();
250 	if (!prop->ipv6_prefixes_cnt)
251 		rc = smc_clc_prfx_match4_rcu(dst->dev, prop);
252 	else
253 		rc = smc_clc_prfx_match6_rcu(dst->dev, prop);
254 	rcu_read_unlock();
255 out_rel:
256 	dst_release(dst);
257 out:
258 	return rc;
259 }
260 
261 /* Wait for data on the tcp-socket, analyze received data
262  * Returns:
263  * 0 if success and it was not a decline that we received.
264  * SMC_CLC_DECL_REPLY if decline received for fallback w/o another decl send.
265  * clcsock error, -EINTR, -ECONNRESET, -EPROTO otherwise.
266  */
267 int smc_clc_wait_msg(struct smc_sock *smc, void *buf, int buflen,
268 		     u8 expected_type, unsigned long timeout)
269 {
270 	long rcvtimeo = smc->clcsock->sk->sk_rcvtimeo;
271 	struct sock *clc_sk = smc->clcsock->sk;
272 	struct smc_clc_msg_hdr *clcm = buf;
273 	struct msghdr msg = {NULL, 0};
274 	int reason_code = 0;
275 	struct kvec vec = {buf, buflen};
276 	int len, datlen;
277 	int krflags;
278 
279 	/* peek the first few bytes to determine length of data to receive
280 	 * so we don't consume any subsequent CLC message or payload data
281 	 * in the TCP byte stream
282 	 */
283 	/*
284 	 * Caller must make sure that buflen is no less than
285 	 * sizeof(struct smc_clc_msg_hdr)
286 	 */
287 	krflags = MSG_PEEK | MSG_WAITALL;
288 	clc_sk->sk_rcvtimeo = timeout;
289 	iov_iter_kvec(&msg.msg_iter, READ, &vec, 1,
290 			sizeof(struct smc_clc_msg_hdr));
291 	len = sock_recvmsg(smc->clcsock, &msg, krflags);
292 	if (signal_pending(current)) {
293 		reason_code = -EINTR;
294 		clc_sk->sk_err = EINTR;
295 		smc->sk.sk_err = EINTR;
296 		goto out;
297 	}
298 	if (clc_sk->sk_err) {
299 		reason_code = -clc_sk->sk_err;
300 		if (clc_sk->sk_err == EAGAIN &&
301 		    expected_type == SMC_CLC_DECLINE)
302 			clc_sk->sk_err = 0; /* reset for fallback usage */
303 		else
304 			smc->sk.sk_err = clc_sk->sk_err;
305 		goto out;
306 	}
307 	if (!len) { /* peer has performed orderly shutdown */
308 		smc->sk.sk_err = ECONNRESET;
309 		reason_code = -ECONNRESET;
310 		goto out;
311 	}
312 	if (len < 0) {
313 		if (len != -EAGAIN || expected_type != SMC_CLC_DECLINE)
314 			smc->sk.sk_err = -len;
315 		reason_code = len;
316 		goto out;
317 	}
318 	datlen = ntohs(clcm->length);
319 	if ((len < sizeof(struct smc_clc_msg_hdr)) ||
320 	    (datlen > buflen) ||
321 	    (clcm->version != SMC_CLC_V1) ||
322 	    (clcm->path != SMC_TYPE_R && clcm->path != SMC_TYPE_D &&
323 	     clcm->path != SMC_TYPE_B) ||
324 	    ((clcm->type != SMC_CLC_DECLINE) &&
325 	     (clcm->type != expected_type))) {
326 		smc->sk.sk_err = EPROTO;
327 		reason_code = -EPROTO;
328 		goto out;
329 	}
330 
331 	/* receive the complete CLC message */
332 	memset(&msg, 0, sizeof(struct msghdr));
333 	iov_iter_kvec(&msg.msg_iter, READ, &vec, 1, datlen);
334 	krflags = MSG_WAITALL;
335 	len = sock_recvmsg(smc->clcsock, &msg, krflags);
336 	if (len < datlen || !smc_clc_msg_hdr_valid(clcm)) {
337 		smc->sk.sk_err = EPROTO;
338 		reason_code = -EPROTO;
339 		goto out;
340 	}
341 	if (clcm->type == SMC_CLC_DECLINE) {
342 		struct smc_clc_msg_decline *dclc;
343 
344 		dclc = (struct smc_clc_msg_decline *)clcm;
345 		reason_code = SMC_CLC_DECL_PEERDECL;
346 		smc->peer_diagnosis = ntohl(dclc->peer_diagnosis);
347 		if (((struct smc_clc_msg_decline *)buf)->hdr.flag) {
348 			smc->conn.lgr->sync_err = 1;
349 			smc_lgr_terminate(smc->conn.lgr);
350 		}
351 	}
352 
353 out:
354 	clc_sk->sk_rcvtimeo = rcvtimeo;
355 	return reason_code;
356 }
357 
358 /* send CLC DECLINE message across internal TCP socket */
359 int smc_clc_send_decline(struct smc_sock *smc, u32 peer_diag_info)
360 {
361 	struct smc_clc_msg_decline dclc;
362 	struct msghdr msg;
363 	struct kvec vec;
364 	int len;
365 
366 	memset(&dclc, 0, sizeof(dclc));
367 	memcpy(dclc.hdr.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
368 	dclc.hdr.type = SMC_CLC_DECLINE;
369 	dclc.hdr.length = htons(sizeof(struct smc_clc_msg_decline));
370 	dclc.hdr.version = SMC_CLC_V1;
371 	dclc.hdr.flag = (peer_diag_info == SMC_CLC_DECL_SYNCERR) ? 1 : 0;
372 	memcpy(dclc.id_for_peer, local_systemid, sizeof(local_systemid));
373 	dclc.peer_diagnosis = htonl(peer_diag_info);
374 	memcpy(dclc.trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
375 
376 	memset(&msg, 0, sizeof(msg));
377 	vec.iov_base = &dclc;
378 	vec.iov_len = sizeof(struct smc_clc_msg_decline);
379 	len = kernel_sendmsg(smc->clcsock, &msg, &vec, 1,
380 			     sizeof(struct smc_clc_msg_decline));
381 	if (len < 0 || len < sizeof(struct smc_clc_msg_decline))
382 		len = -EPROTO;
383 	return len > 0 ? 0 : len;
384 }
385 
386 /* send CLC PROPOSAL message across internal TCP socket */
387 int smc_clc_send_proposal(struct smc_sock *smc, int smc_type,
388 			  struct smc_init_info *ini)
389 {
390 	struct smc_clc_ipv6_prefix ipv6_prfx[SMC_CLC_MAX_V6_PREFIX];
391 	struct smc_clc_msg_proposal_prefix pclc_prfx;
392 	struct smc_clc_msg_smcd pclc_smcd;
393 	struct smc_clc_msg_proposal pclc;
394 	struct smc_clc_msg_trail trl;
395 	int len, i, plen, rc;
396 	int reason_code = 0;
397 	struct kvec vec[5];
398 	struct msghdr msg;
399 
400 	/* retrieve ip prefixes for CLC proposal msg */
401 	rc = smc_clc_prfx_set(smc->clcsock, &pclc_prfx, ipv6_prfx);
402 	if (rc)
403 		return SMC_CLC_DECL_CNFERR; /* configuration error */
404 
405 	/* send SMC Proposal CLC message */
406 	plen = sizeof(pclc) + sizeof(pclc_prfx) +
407 	       (pclc_prfx.ipv6_prefixes_cnt * sizeof(ipv6_prfx[0])) +
408 	       sizeof(trl);
409 	memset(&pclc, 0, sizeof(pclc));
410 	memcpy(pclc.hdr.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
411 	pclc.hdr.type = SMC_CLC_PROPOSAL;
412 	pclc.hdr.version = SMC_CLC_V1;		/* SMC version */
413 	pclc.hdr.path = smc_type;
414 	if (smc_type == SMC_TYPE_R || smc_type == SMC_TYPE_B) {
415 		/* add SMC-R specifics */
416 		memcpy(pclc.lcl.id_for_peer, local_systemid,
417 		       sizeof(local_systemid));
418 		memcpy(&pclc.lcl.gid, ini->ib_gid, SMC_GID_SIZE);
419 		memcpy(&pclc.lcl.mac, &ini->ib_dev->mac[ini->ib_port - 1],
420 		       ETH_ALEN);
421 		pclc.iparea_offset = htons(0);
422 	}
423 	if (smc_type == SMC_TYPE_D || smc_type == SMC_TYPE_B) {
424 		/* add SMC-D specifics */
425 		memset(&pclc_smcd, 0, sizeof(pclc_smcd));
426 		plen += sizeof(pclc_smcd);
427 		pclc.iparea_offset = htons(SMC_CLC_PROPOSAL_MAX_OFFSET);
428 		pclc_smcd.gid = ini->ism_dev->local_gid;
429 	}
430 	pclc.hdr.length = htons(plen);
431 
432 	memcpy(trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
433 	memset(&msg, 0, sizeof(msg));
434 	i = 0;
435 	vec[i].iov_base = &pclc;
436 	vec[i++].iov_len = sizeof(pclc);
437 	if (smc_type == SMC_TYPE_D || smc_type == SMC_TYPE_B) {
438 		vec[i].iov_base = &pclc_smcd;
439 		vec[i++].iov_len = sizeof(pclc_smcd);
440 	}
441 	vec[i].iov_base = &pclc_prfx;
442 	vec[i++].iov_len = sizeof(pclc_prfx);
443 	if (pclc_prfx.ipv6_prefixes_cnt > 0) {
444 		vec[i].iov_base = &ipv6_prfx[0];
445 		vec[i++].iov_len = pclc_prfx.ipv6_prefixes_cnt *
446 				   sizeof(ipv6_prfx[0]);
447 	}
448 	vec[i].iov_base = &trl;
449 	vec[i++].iov_len = sizeof(trl);
450 	/* due to the few bytes needed for clc-handshake this cannot block */
451 	len = kernel_sendmsg(smc->clcsock, &msg, vec, i, plen);
452 	if (len < 0) {
453 		smc->sk.sk_err = smc->clcsock->sk->sk_err;
454 		reason_code = -smc->sk.sk_err;
455 	} else if (len < (int)sizeof(pclc)) {
456 		reason_code = -ENETUNREACH;
457 		smc->sk.sk_err = -reason_code;
458 	}
459 
460 	return reason_code;
461 }
462 
463 /* send CLC CONFIRM message across internal TCP socket */
464 int smc_clc_send_confirm(struct smc_sock *smc)
465 {
466 	struct smc_connection *conn = &smc->conn;
467 	struct smc_clc_msg_accept_confirm cclc;
468 	struct smc_link *link;
469 	int reason_code = 0;
470 	struct msghdr msg;
471 	struct kvec vec;
472 	int len;
473 
474 	/* send SMC Confirm CLC msg */
475 	memset(&cclc, 0, sizeof(cclc));
476 	cclc.hdr.type = SMC_CLC_CONFIRM;
477 	cclc.hdr.version = SMC_CLC_V1;		/* SMC version */
478 	if (smc->conn.lgr->is_smcd) {
479 		/* SMC-D specific settings */
480 		memcpy(cclc.hdr.eyecatcher, SMCD_EYECATCHER,
481 		       sizeof(SMCD_EYECATCHER));
482 		cclc.hdr.path = SMC_TYPE_D;
483 		cclc.hdr.length = htons(SMCD_CLC_ACCEPT_CONFIRM_LEN);
484 		cclc.gid = conn->lgr->smcd->local_gid;
485 		cclc.token = conn->rmb_desc->token;
486 		cclc.dmbe_size = conn->rmbe_size_short;
487 		cclc.dmbe_idx = 0;
488 		memcpy(&cclc.linkid, conn->lgr->id, SMC_LGR_ID_SIZE);
489 		memcpy(cclc.smcd_trl.eyecatcher, SMCD_EYECATCHER,
490 		       sizeof(SMCD_EYECATCHER));
491 	} else {
492 		/* SMC-R specific settings */
493 		link = &conn->lgr->lnk[SMC_SINGLE_LINK];
494 		memcpy(cclc.hdr.eyecatcher, SMC_EYECATCHER,
495 		       sizeof(SMC_EYECATCHER));
496 		cclc.hdr.path = SMC_TYPE_R;
497 		cclc.hdr.length = htons(SMCR_CLC_ACCEPT_CONFIRM_LEN);
498 		memcpy(cclc.lcl.id_for_peer, local_systemid,
499 		       sizeof(local_systemid));
500 		memcpy(&cclc.lcl.gid, link->gid, SMC_GID_SIZE);
501 		memcpy(&cclc.lcl.mac, &link->smcibdev->mac[link->ibport - 1],
502 		       ETH_ALEN);
503 		hton24(cclc.qpn, link->roce_qp->qp_num);
504 		cclc.rmb_rkey =
505 			htonl(conn->rmb_desc->mr_rx[SMC_SINGLE_LINK]->rkey);
506 		cclc.rmbe_idx = 1; /* for now: 1 RMB = 1 RMBE */
507 		cclc.rmbe_alert_token = htonl(conn->alert_token_local);
508 		cclc.qp_mtu = min(link->path_mtu, link->peer_mtu);
509 		cclc.rmbe_size = conn->rmbe_size_short;
510 		cclc.rmb_dma_addr = cpu_to_be64((u64)sg_dma_address
511 				(conn->rmb_desc->sgt[SMC_SINGLE_LINK].sgl));
512 		hton24(cclc.psn, link->psn_initial);
513 		memcpy(cclc.smcr_trl.eyecatcher, SMC_EYECATCHER,
514 		       sizeof(SMC_EYECATCHER));
515 	}
516 
517 	memset(&msg, 0, sizeof(msg));
518 	vec.iov_base = &cclc;
519 	vec.iov_len = ntohs(cclc.hdr.length);
520 	len = kernel_sendmsg(smc->clcsock, &msg, &vec, 1,
521 			     ntohs(cclc.hdr.length));
522 	if (len < ntohs(cclc.hdr.length)) {
523 		if (len >= 0) {
524 			reason_code = -ENETUNREACH;
525 			smc->sk.sk_err = -reason_code;
526 		} else {
527 			smc->sk.sk_err = smc->clcsock->sk->sk_err;
528 			reason_code = -smc->sk.sk_err;
529 		}
530 	}
531 	return reason_code;
532 }
533 
534 /* send CLC ACCEPT message across internal TCP socket */
535 int smc_clc_send_accept(struct smc_sock *new_smc, int srv_first_contact)
536 {
537 	struct smc_connection *conn = &new_smc->conn;
538 	struct smc_clc_msg_accept_confirm aclc;
539 	struct smc_link *link;
540 	struct msghdr msg;
541 	struct kvec vec;
542 	int len;
543 
544 	memset(&aclc, 0, sizeof(aclc));
545 	aclc.hdr.type = SMC_CLC_ACCEPT;
546 	aclc.hdr.version = SMC_CLC_V1;		/* SMC version */
547 	if (srv_first_contact)
548 		aclc.hdr.flag = 1;
549 
550 	if (new_smc->conn.lgr->is_smcd) {
551 		/* SMC-D specific settings */
552 		aclc.hdr.length = htons(SMCD_CLC_ACCEPT_CONFIRM_LEN);
553 		memcpy(aclc.hdr.eyecatcher, SMCD_EYECATCHER,
554 		       sizeof(SMCD_EYECATCHER));
555 		aclc.hdr.path = SMC_TYPE_D;
556 		aclc.gid = conn->lgr->smcd->local_gid;
557 		aclc.token = conn->rmb_desc->token;
558 		aclc.dmbe_size = conn->rmbe_size_short;
559 		aclc.dmbe_idx = 0;
560 		memcpy(&aclc.linkid, conn->lgr->id, SMC_LGR_ID_SIZE);
561 		memcpy(aclc.smcd_trl.eyecatcher, SMCD_EYECATCHER,
562 		       sizeof(SMCD_EYECATCHER));
563 	} else {
564 		/* SMC-R specific settings */
565 		aclc.hdr.length = htons(SMCR_CLC_ACCEPT_CONFIRM_LEN);
566 		memcpy(aclc.hdr.eyecatcher, SMC_EYECATCHER,
567 		       sizeof(SMC_EYECATCHER));
568 		aclc.hdr.path = SMC_TYPE_R;
569 		link = &conn->lgr->lnk[SMC_SINGLE_LINK];
570 		memcpy(aclc.lcl.id_for_peer, local_systemid,
571 		       sizeof(local_systemid));
572 		memcpy(&aclc.lcl.gid, link->gid, SMC_GID_SIZE);
573 		memcpy(&aclc.lcl.mac, link->smcibdev->mac[link->ibport - 1],
574 		       ETH_ALEN);
575 		hton24(aclc.qpn, link->roce_qp->qp_num);
576 		aclc.rmb_rkey =
577 			htonl(conn->rmb_desc->mr_rx[SMC_SINGLE_LINK]->rkey);
578 		aclc.rmbe_idx = 1;		/* as long as 1 RMB = 1 RMBE */
579 		aclc.rmbe_alert_token = htonl(conn->alert_token_local);
580 		aclc.qp_mtu = link->path_mtu;
581 		aclc.rmbe_size = conn->rmbe_size_short,
582 		aclc.rmb_dma_addr = cpu_to_be64((u64)sg_dma_address
583 				(conn->rmb_desc->sgt[SMC_SINGLE_LINK].sgl));
584 		hton24(aclc.psn, link->psn_initial);
585 		memcpy(aclc.smcr_trl.eyecatcher, SMC_EYECATCHER,
586 		       sizeof(SMC_EYECATCHER));
587 	}
588 
589 	memset(&msg, 0, sizeof(msg));
590 	vec.iov_base = &aclc;
591 	vec.iov_len = ntohs(aclc.hdr.length);
592 	len = kernel_sendmsg(new_smc->clcsock, &msg, &vec, 1,
593 			     ntohs(aclc.hdr.length));
594 	if (len < ntohs(aclc.hdr.length))
595 		len = len >= 0 ? -EPROTO : -new_smc->clcsock->sk->sk_err;
596 
597 	return len > 0 ? 0 : len;
598 }
599