xref: /openbmc/linux/net/smc/smc_clc.c (revision 76ce0265)
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 	const struct in_ifaddr *ifa;
101 
102 	if (!in_dev)
103 		return -ENODEV;
104 
105 	in_dev_for_each_ifa_rcu(ifa, in_dev) {
106 		if (!inet_ifa_match(ipv4, ifa))
107 			continue;
108 		prop->prefix_len = inet_mask_len(ifa->ifa_mask);
109 		prop->outgoing_subnet = ifa->ifa_address & ifa->ifa_mask;
110 		/* prop->ipv6_prefixes_cnt = 0; already done by memset before */
111 		return 0;
112 	}
113 	return -ENOENT;
114 }
115 
116 /* fill CLC proposal msg with ipv6 prefixes from device */
117 static int smc_clc_prfx_set6_rcu(struct dst_entry *dst,
118 				 struct smc_clc_msg_proposal_prefix *prop,
119 				 struct smc_clc_ipv6_prefix *ipv6_prfx)
120 {
121 #if IS_ENABLED(CONFIG_IPV6)
122 	struct inet6_dev *in6_dev = __in6_dev_get(dst->dev);
123 	struct inet6_ifaddr *ifa;
124 	int cnt = 0;
125 
126 	if (!in6_dev)
127 		return -ENODEV;
128 	/* use a maximum of 8 IPv6 prefixes from device */
129 	list_for_each_entry(ifa, &in6_dev->addr_list, if_list) {
130 		if (ipv6_addr_type(&ifa->addr) & IPV6_ADDR_LINKLOCAL)
131 			continue;
132 		ipv6_addr_prefix(&ipv6_prfx[cnt].prefix,
133 				 &ifa->addr, ifa->prefix_len);
134 		ipv6_prfx[cnt].prefix_len = ifa->prefix_len;
135 		cnt++;
136 		if (cnt == SMC_CLC_MAX_V6_PREFIX)
137 			break;
138 	}
139 	prop->ipv6_prefixes_cnt = cnt;
140 	if (cnt)
141 		return 0;
142 #endif
143 	return -ENOENT;
144 }
145 
146 /* retrieve and set prefixes in CLC proposal msg */
147 static int smc_clc_prfx_set(struct socket *clcsock,
148 			    struct smc_clc_msg_proposal_prefix *prop,
149 			    struct smc_clc_ipv6_prefix *ipv6_prfx)
150 {
151 	struct dst_entry *dst = sk_dst_get(clcsock->sk);
152 	struct sockaddr_storage addrs;
153 	struct sockaddr_in6 *addr6;
154 	struct sockaddr_in *addr;
155 	int rc = -ENOENT;
156 
157 	memset(prop, 0, sizeof(*prop));
158 	if (!dst) {
159 		rc = -ENOTCONN;
160 		goto out;
161 	}
162 	if (!dst->dev) {
163 		rc = -ENODEV;
164 		goto out_rel;
165 	}
166 	/* get address to which the internal TCP socket is bound */
167 	kernel_getsockname(clcsock, (struct sockaddr *)&addrs);
168 	/* analyze IP specific data of net_device belonging to TCP socket */
169 	addr6 = (struct sockaddr_in6 *)&addrs;
170 	rcu_read_lock();
171 	if (addrs.ss_family == PF_INET) {
172 		/* IPv4 */
173 		addr = (struct sockaddr_in *)&addrs;
174 		rc = smc_clc_prfx_set4_rcu(dst, addr->sin_addr.s_addr, prop);
175 	} else if (ipv6_addr_v4mapped(&addr6->sin6_addr)) {
176 		/* mapped IPv4 address - peer is IPv4 only */
177 		rc = smc_clc_prfx_set4_rcu(dst, addr6->sin6_addr.s6_addr32[3],
178 					   prop);
179 	} else {
180 		/* IPv6 */
181 		rc = smc_clc_prfx_set6_rcu(dst, prop, ipv6_prfx);
182 	}
183 	rcu_read_unlock();
184 out_rel:
185 	dst_release(dst);
186 out:
187 	return rc;
188 }
189 
190 /* match ipv4 addrs of dev against addr in CLC proposal */
191 static int smc_clc_prfx_match4_rcu(struct net_device *dev,
192 				   struct smc_clc_msg_proposal_prefix *prop)
193 {
194 	struct in_device *in_dev = __in_dev_get_rcu(dev);
195 	const struct in_ifaddr *ifa;
196 
197 	if (!in_dev)
198 		return -ENODEV;
199 	in_dev_for_each_ifa_rcu(ifa, in_dev) {
200 		if (prop->prefix_len == inet_mask_len(ifa->ifa_mask) &&
201 		    inet_ifa_match(prop->outgoing_subnet, ifa))
202 			return 0;
203 	}
204 
205 	return -ENOENT;
206 }
207 
208 /* match ipv6 addrs of dev against addrs in CLC proposal */
209 static int smc_clc_prfx_match6_rcu(struct net_device *dev,
210 				   struct smc_clc_msg_proposal_prefix *prop)
211 {
212 #if IS_ENABLED(CONFIG_IPV6)
213 	struct inet6_dev *in6_dev = __in6_dev_get(dev);
214 	struct smc_clc_ipv6_prefix *ipv6_prfx;
215 	struct inet6_ifaddr *ifa;
216 	int i, max;
217 
218 	if (!in6_dev)
219 		return -ENODEV;
220 	/* ipv6 prefix list starts behind smc_clc_msg_proposal_prefix */
221 	ipv6_prfx = (struct smc_clc_ipv6_prefix *)((u8 *)prop + sizeof(*prop));
222 	max = min_t(u8, prop->ipv6_prefixes_cnt, SMC_CLC_MAX_V6_PREFIX);
223 	list_for_each_entry(ifa, &in6_dev->addr_list, if_list) {
224 		if (ipv6_addr_type(&ifa->addr) & IPV6_ADDR_LINKLOCAL)
225 			continue;
226 		for (i = 0; i < max; i++) {
227 			if (ifa->prefix_len == ipv6_prfx[i].prefix_len &&
228 			    ipv6_prefix_equal(&ifa->addr, &ipv6_prfx[i].prefix,
229 					      ifa->prefix_len))
230 				return 0;
231 		}
232 	}
233 #endif
234 	return -ENOENT;
235 }
236 
237 /* check if proposed prefixes match one of our device prefixes */
238 int smc_clc_prfx_match(struct socket *clcsock,
239 		       struct smc_clc_msg_proposal_prefix *prop)
240 {
241 	struct dst_entry *dst = sk_dst_get(clcsock->sk);
242 	int rc;
243 
244 	if (!dst) {
245 		rc = -ENOTCONN;
246 		goto out;
247 	}
248 	if (!dst->dev) {
249 		rc = -ENODEV;
250 		goto out_rel;
251 	}
252 	rcu_read_lock();
253 	if (!prop->ipv6_prefixes_cnt)
254 		rc = smc_clc_prfx_match4_rcu(dst->dev, prop);
255 	else
256 		rc = smc_clc_prfx_match6_rcu(dst->dev, prop);
257 	rcu_read_unlock();
258 out_rel:
259 	dst_release(dst);
260 out:
261 	return rc;
262 }
263 
264 /* Wait for data on the tcp-socket, analyze received data
265  * Returns:
266  * 0 if success and it was not a decline that we received.
267  * SMC_CLC_DECL_REPLY if decline received for fallback w/o another decl send.
268  * clcsock error, -EINTR, -ECONNRESET, -EPROTO otherwise.
269  */
270 int smc_clc_wait_msg(struct smc_sock *smc, void *buf, int buflen,
271 		     u8 expected_type, unsigned long timeout)
272 {
273 	long rcvtimeo = smc->clcsock->sk->sk_rcvtimeo;
274 	struct sock *clc_sk = smc->clcsock->sk;
275 	struct smc_clc_msg_hdr *clcm = buf;
276 	struct msghdr msg = {NULL, 0};
277 	int reason_code = 0;
278 	struct kvec vec = {buf, buflen};
279 	int len, datlen;
280 	int krflags;
281 
282 	/* peek the first few bytes to determine length of data to receive
283 	 * so we don't consume any subsequent CLC message or payload data
284 	 * in the TCP byte stream
285 	 */
286 	/*
287 	 * Caller must make sure that buflen is no less than
288 	 * sizeof(struct smc_clc_msg_hdr)
289 	 */
290 	krflags = MSG_PEEK | MSG_WAITALL;
291 	clc_sk->sk_rcvtimeo = timeout;
292 	iov_iter_kvec(&msg.msg_iter, READ, &vec, 1,
293 			sizeof(struct smc_clc_msg_hdr));
294 	len = sock_recvmsg(smc->clcsock, &msg, krflags);
295 	if (signal_pending(current)) {
296 		reason_code = -EINTR;
297 		clc_sk->sk_err = EINTR;
298 		smc->sk.sk_err = EINTR;
299 		goto out;
300 	}
301 	if (clc_sk->sk_err) {
302 		reason_code = -clc_sk->sk_err;
303 		if (clc_sk->sk_err == EAGAIN &&
304 		    expected_type == SMC_CLC_DECLINE)
305 			clc_sk->sk_err = 0; /* reset for fallback usage */
306 		else
307 			smc->sk.sk_err = clc_sk->sk_err;
308 		goto out;
309 	}
310 	if (!len) { /* peer has performed orderly shutdown */
311 		smc->sk.sk_err = ECONNRESET;
312 		reason_code = -ECONNRESET;
313 		goto out;
314 	}
315 	if (len < 0) {
316 		if (len != -EAGAIN || expected_type != SMC_CLC_DECLINE)
317 			smc->sk.sk_err = -len;
318 		reason_code = len;
319 		goto out;
320 	}
321 	datlen = ntohs(clcm->length);
322 	if ((len < sizeof(struct smc_clc_msg_hdr)) ||
323 	    (datlen > buflen) ||
324 	    (clcm->version != SMC_CLC_V1) ||
325 	    (clcm->path != SMC_TYPE_R && clcm->path != SMC_TYPE_D &&
326 	     clcm->path != SMC_TYPE_B) ||
327 	    ((clcm->type != SMC_CLC_DECLINE) &&
328 	     (clcm->type != expected_type))) {
329 		smc->sk.sk_err = EPROTO;
330 		reason_code = -EPROTO;
331 		goto out;
332 	}
333 
334 	/* receive the complete CLC message */
335 	memset(&msg, 0, sizeof(struct msghdr));
336 	iov_iter_kvec(&msg.msg_iter, READ, &vec, 1, datlen);
337 	krflags = MSG_WAITALL;
338 	len = sock_recvmsg(smc->clcsock, &msg, krflags);
339 	if (len < datlen || !smc_clc_msg_hdr_valid(clcm)) {
340 		smc->sk.sk_err = EPROTO;
341 		reason_code = -EPROTO;
342 		goto out;
343 	}
344 	if (clcm->type == SMC_CLC_DECLINE) {
345 		struct smc_clc_msg_decline *dclc;
346 
347 		dclc = (struct smc_clc_msg_decline *)clcm;
348 		reason_code = SMC_CLC_DECL_PEERDECL;
349 		smc->peer_diagnosis = ntohl(dclc->peer_diagnosis);
350 		if (((struct smc_clc_msg_decline *)buf)->hdr.flag) {
351 			smc->conn.lgr->sync_err = 1;
352 			smc_lgr_terminate(smc->conn.lgr, true);
353 		}
354 	}
355 
356 out:
357 	clc_sk->sk_rcvtimeo = rcvtimeo;
358 	return reason_code;
359 }
360 
361 /* send CLC DECLINE message across internal TCP socket */
362 int smc_clc_send_decline(struct smc_sock *smc, u32 peer_diag_info)
363 {
364 	struct smc_clc_msg_decline dclc;
365 	struct msghdr msg;
366 	struct kvec vec;
367 	int len;
368 
369 	memset(&dclc, 0, sizeof(dclc));
370 	memcpy(dclc.hdr.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
371 	dclc.hdr.type = SMC_CLC_DECLINE;
372 	dclc.hdr.length = htons(sizeof(struct smc_clc_msg_decline));
373 	dclc.hdr.version = SMC_CLC_V1;
374 	dclc.hdr.flag = (peer_diag_info == SMC_CLC_DECL_SYNCERR) ? 1 : 0;
375 	if (smc->conn.lgr && !smc->conn.lgr->is_smcd)
376 		memcpy(dclc.id_for_peer, local_systemid,
377 		       sizeof(local_systemid));
378 	dclc.peer_diagnosis = htonl(peer_diag_info);
379 	memcpy(dclc.trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
380 
381 	memset(&msg, 0, sizeof(msg));
382 	vec.iov_base = &dclc;
383 	vec.iov_len = sizeof(struct smc_clc_msg_decline);
384 	len = kernel_sendmsg(smc->clcsock, &msg, &vec, 1,
385 			     sizeof(struct smc_clc_msg_decline));
386 	if (len < 0 || len < sizeof(struct smc_clc_msg_decline))
387 		len = -EPROTO;
388 	return len > 0 ? 0 : len;
389 }
390 
391 /* send CLC PROPOSAL message across internal TCP socket */
392 int smc_clc_send_proposal(struct smc_sock *smc, int smc_type,
393 			  struct smc_init_info *ini)
394 {
395 	struct smc_clc_ipv6_prefix ipv6_prfx[SMC_CLC_MAX_V6_PREFIX];
396 	struct smc_clc_msg_proposal_prefix pclc_prfx;
397 	struct smc_clc_msg_smcd pclc_smcd;
398 	struct smc_clc_msg_proposal pclc;
399 	struct smc_clc_msg_trail trl;
400 	int len, i, plen, rc;
401 	int reason_code = 0;
402 	struct kvec vec[5];
403 	struct msghdr msg;
404 
405 	/* retrieve ip prefixes for CLC proposal msg */
406 	rc = smc_clc_prfx_set(smc->clcsock, &pclc_prfx, ipv6_prfx);
407 	if (rc)
408 		return SMC_CLC_DECL_CNFERR; /* configuration error */
409 
410 	/* send SMC Proposal CLC message */
411 	plen = sizeof(pclc) + sizeof(pclc_prfx) +
412 	       (pclc_prfx.ipv6_prefixes_cnt * sizeof(ipv6_prfx[0])) +
413 	       sizeof(trl);
414 	memset(&pclc, 0, sizeof(pclc));
415 	memcpy(pclc.hdr.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
416 	pclc.hdr.type = SMC_CLC_PROPOSAL;
417 	pclc.hdr.version = SMC_CLC_V1;		/* SMC version */
418 	pclc.hdr.path = smc_type;
419 	if (smc_type == SMC_TYPE_R || smc_type == SMC_TYPE_B) {
420 		/* add SMC-R specifics */
421 		memcpy(pclc.lcl.id_for_peer, local_systemid,
422 		       sizeof(local_systemid));
423 		memcpy(&pclc.lcl.gid, ini->ib_gid, SMC_GID_SIZE);
424 		memcpy(&pclc.lcl.mac, &ini->ib_dev->mac[ini->ib_port - 1],
425 		       ETH_ALEN);
426 		pclc.iparea_offset = htons(0);
427 	}
428 	if (smc_type == SMC_TYPE_D || smc_type == SMC_TYPE_B) {
429 		/* add SMC-D specifics */
430 		memset(&pclc_smcd, 0, sizeof(pclc_smcd));
431 		plen += sizeof(pclc_smcd);
432 		pclc.iparea_offset = htons(SMC_CLC_PROPOSAL_MAX_OFFSET);
433 		pclc_smcd.gid = ini->ism_dev->local_gid;
434 	}
435 	pclc.hdr.length = htons(plen);
436 
437 	memcpy(trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
438 	memset(&msg, 0, sizeof(msg));
439 	i = 0;
440 	vec[i].iov_base = &pclc;
441 	vec[i++].iov_len = sizeof(pclc);
442 	if (smc_type == SMC_TYPE_D || smc_type == SMC_TYPE_B) {
443 		vec[i].iov_base = &pclc_smcd;
444 		vec[i++].iov_len = sizeof(pclc_smcd);
445 	}
446 	vec[i].iov_base = &pclc_prfx;
447 	vec[i++].iov_len = sizeof(pclc_prfx);
448 	if (pclc_prfx.ipv6_prefixes_cnt > 0) {
449 		vec[i].iov_base = &ipv6_prfx[0];
450 		vec[i++].iov_len = pclc_prfx.ipv6_prefixes_cnt *
451 				   sizeof(ipv6_prfx[0]);
452 	}
453 	vec[i].iov_base = &trl;
454 	vec[i++].iov_len = sizeof(trl);
455 	/* due to the few bytes needed for clc-handshake this cannot block */
456 	len = kernel_sendmsg(smc->clcsock, &msg, vec, i, plen);
457 	if (len < 0) {
458 		smc->sk.sk_err = smc->clcsock->sk->sk_err;
459 		reason_code = -smc->sk.sk_err;
460 	} else if (len < (int)sizeof(pclc)) {
461 		reason_code = -ENETUNREACH;
462 		smc->sk.sk_err = -reason_code;
463 	}
464 
465 	return reason_code;
466 }
467 
468 /* send CLC CONFIRM message across internal TCP socket */
469 int smc_clc_send_confirm(struct smc_sock *smc)
470 {
471 	struct smc_connection *conn = &smc->conn;
472 	struct smc_clc_msg_accept_confirm cclc;
473 	struct smc_link *link;
474 	int reason_code = 0;
475 	struct msghdr msg;
476 	struct kvec vec;
477 	int len;
478 
479 	/* send SMC Confirm CLC msg */
480 	memset(&cclc, 0, sizeof(cclc));
481 	cclc.hdr.type = SMC_CLC_CONFIRM;
482 	cclc.hdr.version = SMC_CLC_V1;		/* SMC version */
483 	if (smc->conn.lgr->is_smcd) {
484 		/* SMC-D specific settings */
485 		memcpy(cclc.hdr.eyecatcher, SMCD_EYECATCHER,
486 		       sizeof(SMCD_EYECATCHER));
487 		cclc.hdr.path = SMC_TYPE_D;
488 		cclc.hdr.length = htons(SMCD_CLC_ACCEPT_CONFIRM_LEN);
489 		cclc.gid = conn->lgr->smcd->local_gid;
490 		cclc.token = conn->rmb_desc->token;
491 		cclc.dmbe_size = conn->rmbe_size_short;
492 		cclc.dmbe_idx = 0;
493 		memcpy(&cclc.linkid, conn->lgr->id, SMC_LGR_ID_SIZE);
494 		memcpy(cclc.smcd_trl.eyecatcher, SMCD_EYECATCHER,
495 		       sizeof(SMCD_EYECATCHER));
496 	} else {
497 		/* SMC-R specific settings */
498 		link = &conn->lgr->lnk[SMC_SINGLE_LINK];
499 		memcpy(cclc.hdr.eyecatcher, SMC_EYECATCHER,
500 		       sizeof(SMC_EYECATCHER));
501 		cclc.hdr.path = SMC_TYPE_R;
502 		cclc.hdr.length = htons(SMCR_CLC_ACCEPT_CONFIRM_LEN);
503 		memcpy(cclc.lcl.id_for_peer, local_systemid,
504 		       sizeof(local_systemid));
505 		memcpy(&cclc.lcl.gid, link->gid, SMC_GID_SIZE);
506 		memcpy(&cclc.lcl.mac, &link->smcibdev->mac[link->ibport - 1],
507 		       ETH_ALEN);
508 		hton24(cclc.qpn, link->roce_qp->qp_num);
509 		cclc.rmb_rkey =
510 			htonl(conn->rmb_desc->mr_rx[SMC_SINGLE_LINK]->rkey);
511 		cclc.rmbe_idx = 1; /* for now: 1 RMB = 1 RMBE */
512 		cclc.rmbe_alert_token = htonl(conn->alert_token_local);
513 		cclc.qp_mtu = min(link->path_mtu, link->peer_mtu);
514 		cclc.rmbe_size = conn->rmbe_size_short;
515 		cclc.rmb_dma_addr = cpu_to_be64((u64)sg_dma_address
516 				(conn->rmb_desc->sgt[SMC_SINGLE_LINK].sgl));
517 		hton24(cclc.psn, link->psn_initial);
518 		memcpy(cclc.smcr_trl.eyecatcher, SMC_EYECATCHER,
519 		       sizeof(SMC_EYECATCHER));
520 	}
521 
522 	memset(&msg, 0, sizeof(msg));
523 	vec.iov_base = &cclc;
524 	vec.iov_len = ntohs(cclc.hdr.length);
525 	len = kernel_sendmsg(smc->clcsock, &msg, &vec, 1,
526 			     ntohs(cclc.hdr.length));
527 	if (len < ntohs(cclc.hdr.length)) {
528 		if (len >= 0) {
529 			reason_code = -ENETUNREACH;
530 			smc->sk.sk_err = -reason_code;
531 		} else {
532 			smc->sk.sk_err = smc->clcsock->sk->sk_err;
533 			reason_code = -smc->sk.sk_err;
534 		}
535 	}
536 	return reason_code;
537 }
538 
539 /* send CLC ACCEPT message across internal TCP socket */
540 int smc_clc_send_accept(struct smc_sock *new_smc, int srv_first_contact)
541 {
542 	struct smc_connection *conn = &new_smc->conn;
543 	struct smc_clc_msg_accept_confirm aclc;
544 	struct smc_link *link;
545 	struct msghdr msg;
546 	struct kvec vec;
547 	int len;
548 
549 	memset(&aclc, 0, sizeof(aclc));
550 	aclc.hdr.type = SMC_CLC_ACCEPT;
551 	aclc.hdr.version = SMC_CLC_V1;		/* SMC version */
552 	if (srv_first_contact)
553 		aclc.hdr.flag = 1;
554 
555 	if (new_smc->conn.lgr->is_smcd) {
556 		/* SMC-D specific settings */
557 		aclc.hdr.length = htons(SMCD_CLC_ACCEPT_CONFIRM_LEN);
558 		memcpy(aclc.hdr.eyecatcher, SMCD_EYECATCHER,
559 		       sizeof(SMCD_EYECATCHER));
560 		aclc.hdr.path = SMC_TYPE_D;
561 		aclc.gid = conn->lgr->smcd->local_gid;
562 		aclc.token = conn->rmb_desc->token;
563 		aclc.dmbe_size = conn->rmbe_size_short;
564 		aclc.dmbe_idx = 0;
565 		memcpy(&aclc.linkid, conn->lgr->id, SMC_LGR_ID_SIZE);
566 		memcpy(aclc.smcd_trl.eyecatcher, SMCD_EYECATCHER,
567 		       sizeof(SMCD_EYECATCHER));
568 	} else {
569 		/* SMC-R specific settings */
570 		aclc.hdr.length = htons(SMCR_CLC_ACCEPT_CONFIRM_LEN);
571 		memcpy(aclc.hdr.eyecatcher, SMC_EYECATCHER,
572 		       sizeof(SMC_EYECATCHER));
573 		aclc.hdr.path = SMC_TYPE_R;
574 		link = &conn->lgr->lnk[SMC_SINGLE_LINK];
575 		memcpy(aclc.lcl.id_for_peer, local_systemid,
576 		       sizeof(local_systemid));
577 		memcpy(&aclc.lcl.gid, link->gid, SMC_GID_SIZE);
578 		memcpy(&aclc.lcl.mac, link->smcibdev->mac[link->ibport - 1],
579 		       ETH_ALEN);
580 		hton24(aclc.qpn, link->roce_qp->qp_num);
581 		aclc.rmb_rkey =
582 			htonl(conn->rmb_desc->mr_rx[SMC_SINGLE_LINK]->rkey);
583 		aclc.rmbe_idx = 1;		/* as long as 1 RMB = 1 RMBE */
584 		aclc.rmbe_alert_token = htonl(conn->alert_token_local);
585 		aclc.qp_mtu = link->path_mtu;
586 		aclc.rmbe_size = conn->rmbe_size_short,
587 		aclc.rmb_dma_addr = cpu_to_be64((u64)sg_dma_address
588 				(conn->rmb_desc->sgt[SMC_SINGLE_LINK].sgl));
589 		hton24(aclc.psn, link->psn_initial);
590 		memcpy(aclc.smcr_trl.eyecatcher, SMC_EYECATCHER,
591 		       sizeof(SMC_EYECATCHER));
592 	}
593 
594 	memset(&msg, 0, sizeof(msg));
595 	vec.iov_base = &aclc;
596 	vec.iov_len = ntohs(aclc.hdr.length);
597 	len = kernel_sendmsg(new_smc->clcsock, &msg, &vec, 1,
598 			     ntohs(aclc.hdr.length));
599 	if (len < ntohs(aclc.hdr.length))
600 		len = len >= 0 ? -EPROTO : -new_smc->clcsock->sk->sk_err;
601 
602 	return len > 0 ? 0 : len;
603 }
604