xref: /linux/net/smc/smc_clc.c (revision fb4f7926)
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 #define SMC_CLC_RECV_BUF_LEN	100
31 
32 /* eye catcher "SMCR" EBCDIC for CLC messages */
33 static const char SMC_EYECATCHER[4] = {'\xe2', '\xd4', '\xc3', '\xd9'};
34 /* eye catcher "SMCD" EBCDIC for CLC messages */
35 static const char SMCD_EYECATCHER[4] = {'\xe2', '\xd4', '\xc3', '\xc4'};
36 
37 /* check if received message has a correct header length and contains valid
38  * heading and trailing eyecatchers
39  */
40 static bool smc_clc_msg_hdr_valid(struct smc_clc_msg_hdr *clcm, bool check_trl)
41 {
42 	struct smc_clc_msg_proposal_prefix *pclc_prfx;
43 	struct smc_clc_msg_accept_confirm *clc;
44 	struct smc_clc_msg_proposal *pclc;
45 	struct smc_clc_msg_decline *dclc;
46 	struct smc_clc_msg_trail *trl;
47 
48 	if (memcmp(clcm->eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER)) &&
49 	    memcmp(clcm->eyecatcher, SMCD_EYECATCHER, sizeof(SMCD_EYECATCHER)))
50 		return false;
51 	switch (clcm->type) {
52 	case SMC_CLC_PROPOSAL:
53 		pclc = (struct smc_clc_msg_proposal *)clcm;
54 		pclc_prfx = smc_clc_proposal_get_prefix(pclc);
55 		if (ntohs(pclc->hdr.length) <
56 			sizeof(*pclc) + ntohs(pclc->iparea_offset) +
57 			sizeof(*pclc_prfx) +
58 			pclc_prfx->ipv6_prefixes_cnt *
59 				sizeof(struct smc_clc_ipv6_prefix) +
60 			sizeof(*trl))
61 			return false;
62 		trl = (struct smc_clc_msg_trail *)
63 			((u8 *)pclc + ntohs(pclc->hdr.length) - sizeof(*trl));
64 		break;
65 	case SMC_CLC_ACCEPT:
66 	case SMC_CLC_CONFIRM:
67 		if (clcm->path != SMC_TYPE_R && clcm->path != SMC_TYPE_D)
68 			return false;
69 		clc = (struct smc_clc_msg_accept_confirm *)clcm;
70 		if ((clcm->path == SMC_TYPE_R &&
71 		     ntohs(clc->hdr.length) != SMCR_CLC_ACCEPT_CONFIRM_LEN) ||
72 		    (clcm->path == SMC_TYPE_D &&
73 		     ntohs(clc->hdr.length) != SMCD_CLC_ACCEPT_CONFIRM_LEN))
74 			return false;
75 		trl = (struct smc_clc_msg_trail *)
76 			((u8 *)clc + ntohs(clc->hdr.length) - sizeof(*trl));
77 		break;
78 	case SMC_CLC_DECLINE:
79 		dclc = (struct smc_clc_msg_decline *)clcm;
80 		if (ntohs(dclc->hdr.length) != sizeof(*dclc))
81 			return false;
82 		trl = &dclc->trl;
83 		break;
84 	default:
85 		return false;
86 	}
87 	if (check_trl &&
88 	    memcmp(trl->eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER)) &&
89 	    memcmp(trl->eyecatcher, SMCD_EYECATCHER, sizeof(SMCD_EYECATCHER)))
90 		return false;
91 	return true;
92 }
93 
94 /* find ipv4 addr on device and get the prefix len, fill CLC proposal msg */
95 static int smc_clc_prfx_set4_rcu(struct dst_entry *dst, __be32 ipv4,
96 				 struct smc_clc_msg_proposal_prefix *prop)
97 {
98 	struct in_device *in_dev = __in_dev_get_rcu(dst->dev);
99 	const struct in_ifaddr *ifa;
100 
101 	if (!in_dev)
102 		return -ENODEV;
103 
104 	in_dev_for_each_ifa_rcu(ifa, in_dev) {
105 		if (!inet_ifa_match(ipv4, ifa))
106 			continue;
107 		prop->prefix_len = inet_mask_len(ifa->ifa_mask);
108 		prop->outgoing_subnet = ifa->ifa_address & ifa->ifa_mask;
109 		/* prop->ipv6_prefixes_cnt = 0; already done by memset before */
110 		return 0;
111 	}
112 	return -ENOENT;
113 }
114 
115 /* fill CLC proposal msg with ipv6 prefixes from device */
116 static int smc_clc_prfx_set6_rcu(struct dst_entry *dst,
117 				 struct smc_clc_msg_proposal_prefix *prop,
118 				 struct smc_clc_ipv6_prefix *ipv6_prfx)
119 {
120 #if IS_ENABLED(CONFIG_IPV6)
121 	struct inet6_dev *in6_dev = __in6_dev_get(dst->dev);
122 	struct inet6_ifaddr *ifa;
123 	int cnt = 0;
124 
125 	if (!in6_dev)
126 		return -ENODEV;
127 	/* use a maximum of 8 IPv6 prefixes from device */
128 	list_for_each_entry(ifa, &in6_dev->addr_list, if_list) {
129 		if (ipv6_addr_type(&ifa->addr) & IPV6_ADDR_LINKLOCAL)
130 			continue;
131 		ipv6_addr_prefix(&ipv6_prfx[cnt].prefix,
132 				 &ifa->addr, ifa->prefix_len);
133 		ipv6_prfx[cnt].prefix_len = ifa->prefix_len;
134 		cnt++;
135 		if (cnt == SMC_CLC_MAX_V6_PREFIX)
136 			break;
137 	}
138 	prop->ipv6_prefixes_cnt = cnt;
139 	if (cnt)
140 		return 0;
141 #endif
142 	return -ENOENT;
143 }
144 
145 /* retrieve and set prefixes in CLC proposal msg */
146 static int smc_clc_prfx_set(struct socket *clcsock,
147 			    struct smc_clc_msg_proposal_prefix *prop,
148 			    struct smc_clc_ipv6_prefix *ipv6_prfx)
149 {
150 	struct dst_entry *dst = sk_dst_get(clcsock->sk);
151 	struct sockaddr_storage addrs;
152 	struct sockaddr_in6 *addr6;
153 	struct sockaddr_in *addr;
154 	int rc = -ENOENT;
155 
156 	memset(prop, 0, sizeof(*prop));
157 	if (!dst) {
158 		rc = -ENOTCONN;
159 		goto out;
160 	}
161 	if (!dst->dev) {
162 		rc = -ENODEV;
163 		goto out_rel;
164 	}
165 	/* get address to which the internal TCP socket is bound */
166 	kernel_getsockname(clcsock, (struct sockaddr *)&addrs);
167 	/* analyze IP specific data of net_device belonging to TCP socket */
168 	addr6 = (struct sockaddr_in6 *)&addrs;
169 	rcu_read_lock();
170 	if (addrs.ss_family == PF_INET) {
171 		/* IPv4 */
172 		addr = (struct sockaddr_in *)&addrs;
173 		rc = smc_clc_prfx_set4_rcu(dst, addr->sin_addr.s_addr, prop);
174 	} else if (ipv6_addr_v4mapped(&addr6->sin6_addr)) {
175 		/* mapped IPv4 address - peer is IPv4 only */
176 		rc = smc_clc_prfx_set4_rcu(dst, addr6->sin6_addr.s6_addr32[3],
177 					   prop);
178 	} else {
179 		/* IPv6 */
180 		rc = smc_clc_prfx_set6_rcu(dst, prop, ipv6_prfx);
181 	}
182 	rcu_read_unlock();
183 out_rel:
184 	dst_release(dst);
185 out:
186 	return rc;
187 }
188 
189 /* match ipv4 addrs of dev against addr in CLC proposal */
190 static int smc_clc_prfx_match4_rcu(struct net_device *dev,
191 				   struct smc_clc_msg_proposal_prefix *prop)
192 {
193 	struct in_device *in_dev = __in_dev_get_rcu(dev);
194 	const struct in_ifaddr *ifa;
195 
196 	if (!in_dev)
197 		return -ENODEV;
198 	in_dev_for_each_ifa_rcu(ifa, in_dev) {
199 		if (prop->prefix_len == inet_mask_len(ifa->ifa_mask) &&
200 		    inet_ifa_match(prop->outgoing_subnet, ifa))
201 			return 0;
202 	}
203 
204 	return -ENOENT;
205 }
206 
207 /* match ipv6 addrs of dev against addrs in CLC proposal */
208 static int smc_clc_prfx_match6_rcu(struct net_device *dev,
209 				   struct smc_clc_msg_proposal_prefix *prop)
210 {
211 #if IS_ENABLED(CONFIG_IPV6)
212 	struct inet6_dev *in6_dev = __in6_dev_get(dev);
213 	struct smc_clc_ipv6_prefix *ipv6_prfx;
214 	struct inet6_ifaddr *ifa;
215 	int i, max;
216 
217 	if (!in6_dev)
218 		return -ENODEV;
219 	/* ipv6 prefix list starts behind smc_clc_msg_proposal_prefix */
220 	ipv6_prfx = (struct smc_clc_ipv6_prefix *)((u8 *)prop + sizeof(*prop));
221 	max = min_t(u8, prop->ipv6_prefixes_cnt, SMC_CLC_MAX_V6_PREFIX);
222 	list_for_each_entry(ifa, &in6_dev->addr_list, if_list) {
223 		if (ipv6_addr_type(&ifa->addr) & IPV6_ADDR_LINKLOCAL)
224 			continue;
225 		for (i = 0; i < max; i++) {
226 			if (ifa->prefix_len == ipv6_prfx[i].prefix_len &&
227 			    ipv6_prefix_equal(&ifa->addr, &ipv6_prfx[i].prefix,
228 					      ifa->prefix_len))
229 				return 0;
230 		}
231 	}
232 #endif
233 	return -ENOENT;
234 }
235 
236 /* check if proposed prefixes match one of our device prefixes */
237 int smc_clc_prfx_match(struct socket *clcsock,
238 		       struct smc_clc_msg_proposal_prefix *prop)
239 {
240 	struct dst_entry *dst = sk_dst_get(clcsock->sk);
241 	int rc;
242 
243 	if (!dst) {
244 		rc = -ENOTCONN;
245 		goto out;
246 	}
247 	if (!dst->dev) {
248 		rc = -ENODEV;
249 		goto out_rel;
250 	}
251 	rcu_read_lock();
252 	if (!prop->ipv6_prefixes_cnt)
253 		rc = smc_clc_prfx_match4_rcu(dst->dev, prop);
254 	else
255 		rc = smc_clc_prfx_match6_rcu(dst->dev, prop);
256 	rcu_read_unlock();
257 out_rel:
258 	dst_release(dst);
259 out:
260 	return rc;
261 }
262 
263 /* Wait for data on the tcp-socket, analyze received data
264  * Returns:
265  * 0 if success and it was not a decline that we received.
266  * SMC_CLC_DECL_REPLY if decline received for fallback w/o another decl send.
267  * clcsock error, -EINTR, -ECONNRESET, -EPROTO otherwise.
268  */
269 int smc_clc_wait_msg(struct smc_sock *smc, void *buf, int buflen,
270 		     u8 expected_type, unsigned long timeout)
271 {
272 	long rcvtimeo = smc->clcsock->sk->sk_rcvtimeo;
273 	struct sock *clc_sk = smc->clcsock->sk;
274 	struct smc_clc_msg_hdr *clcm = buf;
275 	struct msghdr msg = {NULL, 0};
276 	int reason_code = 0;
277 	struct kvec vec = {buf, buflen};
278 	int len, datlen, recvlen;
279 	bool check_trl = true;
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 	    (clcm->version < SMC_CLC_V1) ||
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 	if (clcm->type == SMC_CLC_PROPOSAL && clcm->path == SMC_TYPE_N)
332 		reason_code = SMC_CLC_DECL_VERSMISMAT; /* just V2 offered */
333 
334 	/* receive the complete CLC message */
335 	memset(&msg, 0, sizeof(struct msghdr));
336 	if (datlen > buflen) {
337 		check_trl = false;
338 		recvlen = buflen;
339 	} else {
340 		recvlen = datlen;
341 	}
342 	iov_iter_kvec(&msg.msg_iter, READ, &vec, 1, recvlen);
343 	krflags = MSG_WAITALL;
344 	len = sock_recvmsg(smc->clcsock, &msg, krflags);
345 	if (len < recvlen || !smc_clc_msg_hdr_valid(clcm, check_trl)) {
346 		smc->sk.sk_err = EPROTO;
347 		reason_code = -EPROTO;
348 		goto out;
349 	}
350 	datlen -= len;
351 	while (datlen) {
352 		u8 tmp[SMC_CLC_RECV_BUF_LEN];
353 
354 		vec.iov_base = &tmp;
355 		vec.iov_len = SMC_CLC_RECV_BUF_LEN;
356 		/* receive remaining proposal message */
357 		recvlen = datlen > SMC_CLC_RECV_BUF_LEN ?
358 						SMC_CLC_RECV_BUF_LEN : datlen;
359 		iov_iter_kvec(&msg.msg_iter, READ, &vec, 1, recvlen);
360 		len = sock_recvmsg(smc->clcsock, &msg, krflags);
361 		datlen -= len;
362 	}
363 	if (clcm->type == SMC_CLC_DECLINE) {
364 		struct smc_clc_msg_decline *dclc;
365 
366 		dclc = (struct smc_clc_msg_decline *)clcm;
367 		reason_code = SMC_CLC_DECL_PEERDECL;
368 		smc->peer_diagnosis = ntohl(dclc->peer_diagnosis);
369 		if (((struct smc_clc_msg_decline *)buf)->hdr.flag) {
370 			smc->conn.lgr->sync_err = 1;
371 			smc_lgr_terminate_sched(smc->conn.lgr);
372 		}
373 	}
374 
375 out:
376 	clc_sk->sk_rcvtimeo = rcvtimeo;
377 	return reason_code;
378 }
379 
380 /* send CLC DECLINE message across internal TCP socket */
381 int smc_clc_send_decline(struct smc_sock *smc, u32 peer_diag_info)
382 {
383 	struct smc_clc_msg_decline dclc;
384 	struct msghdr msg;
385 	struct kvec vec;
386 	int len;
387 
388 	memset(&dclc, 0, sizeof(dclc));
389 	memcpy(dclc.hdr.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
390 	dclc.hdr.type = SMC_CLC_DECLINE;
391 	dclc.hdr.length = htons(sizeof(struct smc_clc_msg_decline));
392 	dclc.hdr.version = SMC_CLC_V1;
393 	dclc.hdr.flag = (peer_diag_info == SMC_CLC_DECL_SYNCERR) ? 1 : 0;
394 	if ((!smc->conn.lgr || !smc->conn.lgr->is_smcd) &&
395 	    smc_ib_is_valid_local_systemid())
396 		memcpy(dclc.id_for_peer, local_systemid,
397 		       sizeof(local_systemid));
398 	dclc.peer_diagnosis = htonl(peer_diag_info);
399 	memcpy(dclc.trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
400 
401 	memset(&msg, 0, sizeof(msg));
402 	vec.iov_base = &dclc;
403 	vec.iov_len = sizeof(struct smc_clc_msg_decline);
404 	len = kernel_sendmsg(smc->clcsock, &msg, &vec, 1,
405 			     sizeof(struct smc_clc_msg_decline));
406 	if (len < 0 || len < sizeof(struct smc_clc_msg_decline))
407 		len = -EPROTO;
408 	return len > 0 ? 0 : len;
409 }
410 
411 /* send CLC PROPOSAL message across internal TCP socket */
412 int smc_clc_send_proposal(struct smc_sock *smc, int smc_type,
413 			  struct smc_init_info *ini)
414 {
415 	struct smc_clc_ipv6_prefix ipv6_prfx[SMC_CLC_MAX_V6_PREFIX];
416 	struct smc_clc_msg_proposal_prefix pclc_prfx;
417 	struct smc_clc_msg_smcd pclc_smcd;
418 	struct smc_clc_msg_proposal pclc;
419 	struct smc_clc_msg_trail trl;
420 	int len, i, plen, rc;
421 	int reason_code = 0;
422 	struct kvec vec[5];
423 	struct msghdr msg;
424 
425 	/* retrieve ip prefixes for CLC proposal msg */
426 	rc = smc_clc_prfx_set(smc->clcsock, &pclc_prfx, ipv6_prfx);
427 	if (rc)
428 		return SMC_CLC_DECL_CNFERR; /* configuration error */
429 
430 	/* send SMC Proposal CLC message */
431 	plen = sizeof(pclc) + sizeof(pclc_prfx) +
432 	       (pclc_prfx.ipv6_prefixes_cnt * sizeof(ipv6_prfx[0])) +
433 	       sizeof(trl);
434 	memset(&pclc, 0, sizeof(pclc));
435 	memcpy(pclc.hdr.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
436 	pclc.hdr.type = SMC_CLC_PROPOSAL;
437 	pclc.hdr.version = SMC_CLC_V1;		/* SMC version */
438 	pclc.hdr.path = smc_type;
439 	if (smc_type == SMC_TYPE_R || smc_type == SMC_TYPE_B) {
440 		/* add SMC-R specifics */
441 		memcpy(pclc.lcl.id_for_peer, local_systemid,
442 		       sizeof(local_systemid));
443 		memcpy(&pclc.lcl.gid, ini->ib_gid, SMC_GID_SIZE);
444 		memcpy(&pclc.lcl.mac, &ini->ib_dev->mac[ini->ib_port - 1],
445 		       ETH_ALEN);
446 		pclc.iparea_offset = htons(0);
447 	}
448 	if (smc_type == SMC_TYPE_D || smc_type == SMC_TYPE_B) {
449 		/* add SMC-D specifics */
450 		memset(&pclc_smcd, 0, sizeof(pclc_smcd));
451 		plen += sizeof(pclc_smcd);
452 		pclc.iparea_offset = htons(SMC_CLC_PROPOSAL_MAX_OFFSET);
453 		pclc_smcd.gid = ini->ism_dev->local_gid;
454 	}
455 	pclc.hdr.length = htons(plen);
456 
457 	memcpy(trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
458 	memset(&msg, 0, sizeof(msg));
459 	i = 0;
460 	vec[i].iov_base = &pclc;
461 	vec[i++].iov_len = sizeof(pclc);
462 	if (smc_type == SMC_TYPE_D || smc_type == SMC_TYPE_B) {
463 		vec[i].iov_base = &pclc_smcd;
464 		vec[i++].iov_len = sizeof(pclc_smcd);
465 	}
466 	vec[i].iov_base = &pclc_prfx;
467 	vec[i++].iov_len = sizeof(pclc_prfx);
468 	if (pclc_prfx.ipv6_prefixes_cnt > 0) {
469 		vec[i].iov_base = &ipv6_prfx[0];
470 		vec[i++].iov_len = pclc_prfx.ipv6_prefixes_cnt *
471 				   sizeof(ipv6_prfx[0]);
472 	}
473 	vec[i].iov_base = &trl;
474 	vec[i++].iov_len = sizeof(trl);
475 	/* due to the few bytes needed for clc-handshake this cannot block */
476 	len = kernel_sendmsg(smc->clcsock, &msg, vec, i, plen);
477 	if (len < 0) {
478 		smc->sk.sk_err = smc->clcsock->sk->sk_err;
479 		reason_code = -smc->sk.sk_err;
480 	} else if (len < (int)sizeof(pclc)) {
481 		reason_code = -ENETUNREACH;
482 		smc->sk.sk_err = -reason_code;
483 	}
484 
485 	return reason_code;
486 }
487 
488 /* send CLC CONFIRM message across internal TCP socket */
489 int smc_clc_send_confirm(struct smc_sock *smc)
490 {
491 	struct smc_connection *conn = &smc->conn;
492 	struct smc_clc_msg_accept_confirm cclc;
493 	struct smc_link *link;
494 	int reason_code = 0;
495 	struct msghdr msg;
496 	struct kvec vec;
497 	int len;
498 
499 	/* send SMC Confirm CLC msg */
500 	memset(&cclc, 0, sizeof(cclc));
501 	cclc.hdr.type = SMC_CLC_CONFIRM;
502 	cclc.hdr.version = SMC_CLC_V1;		/* SMC version */
503 	if (smc->conn.lgr->is_smcd) {
504 		/* SMC-D specific settings */
505 		memcpy(cclc.hdr.eyecatcher, SMCD_EYECATCHER,
506 		       sizeof(SMCD_EYECATCHER));
507 		cclc.hdr.path = SMC_TYPE_D;
508 		cclc.hdr.length = htons(SMCD_CLC_ACCEPT_CONFIRM_LEN);
509 		cclc.gid = conn->lgr->smcd->local_gid;
510 		cclc.token = conn->rmb_desc->token;
511 		cclc.dmbe_size = conn->rmbe_size_short;
512 		cclc.dmbe_idx = 0;
513 		memcpy(&cclc.linkid, conn->lgr->id, SMC_LGR_ID_SIZE);
514 		memcpy(cclc.smcd_trl.eyecatcher, SMCD_EYECATCHER,
515 		       sizeof(SMCD_EYECATCHER));
516 	} else {
517 		/* SMC-R specific settings */
518 		link = conn->lnk;
519 		memcpy(cclc.hdr.eyecatcher, SMC_EYECATCHER,
520 		       sizeof(SMC_EYECATCHER));
521 		cclc.hdr.path = SMC_TYPE_R;
522 		cclc.hdr.length = htons(SMCR_CLC_ACCEPT_CONFIRM_LEN);
523 		memcpy(cclc.lcl.id_for_peer, local_systemid,
524 		       sizeof(local_systemid));
525 		memcpy(&cclc.lcl.gid, link->gid, SMC_GID_SIZE);
526 		memcpy(&cclc.lcl.mac, &link->smcibdev->mac[link->ibport - 1],
527 		       ETH_ALEN);
528 		hton24(cclc.qpn, link->roce_qp->qp_num);
529 		cclc.rmb_rkey =
530 			htonl(conn->rmb_desc->mr_rx[link->link_idx]->rkey);
531 		cclc.rmbe_idx = 1; /* for now: 1 RMB = 1 RMBE */
532 		cclc.rmbe_alert_token = htonl(conn->alert_token_local);
533 		cclc.qp_mtu = min(link->path_mtu, link->peer_mtu);
534 		cclc.rmbe_size = conn->rmbe_size_short;
535 		cclc.rmb_dma_addr = cpu_to_be64((u64)sg_dma_address
536 				(conn->rmb_desc->sgt[link->link_idx].sgl));
537 		hton24(cclc.psn, link->psn_initial);
538 		memcpy(cclc.smcr_trl.eyecatcher, SMC_EYECATCHER,
539 		       sizeof(SMC_EYECATCHER));
540 	}
541 
542 	memset(&msg, 0, sizeof(msg));
543 	vec.iov_base = &cclc;
544 	vec.iov_len = ntohs(cclc.hdr.length);
545 	len = kernel_sendmsg(smc->clcsock, &msg, &vec, 1,
546 			     ntohs(cclc.hdr.length));
547 	if (len < ntohs(cclc.hdr.length)) {
548 		if (len >= 0) {
549 			reason_code = -ENETUNREACH;
550 			smc->sk.sk_err = -reason_code;
551 		} else {
552 			smc->sk.sk_err = smc->clcsock->sk->sk_err;
553 			reason_code = -smc->sk.sk_err;
554 		}
555 	}
556 	return reason_code;
557 }
558 
559 /* send CLC ACCEPT message across internal TCP socket */
560 int smc_clc_send_accept(struct smc_sock *new_smc, int srv_first_contact)
561 {
562 	struct smc_connection *conn = &new_smc->conn;
563 	struct smc_clc_msg_accept_confirm aclc;
564 	struct smc_link *link;
565 	struct msghdr msg;
566 	struct kvec vec;
567 	int len;
568 
569 	memset(&aclc, 0, sizeof(aclc));
570 	aclc.hdr.type = SMC_CLC_ACCEPT;
571 	aclc.hdr.version = SMC_CLC_V1;		/* SMC version */
572 	if (srv_first_contact)
573 		aclc.hdr.flag = 1;
574 
575 	if (new_smc->conn.lgr->is_smcd) {
576 		/* SMC-D specific settings */
577 		aclc.hdr.length = htons(SMCD_CLC_ACCEPT_CONFIRM_LEN);
578 		memcpy(aclc.hdr.eyecatcher, SMCD_EYECATCHER,
579 		       sizeof(SMCD_EYECATCHER));
580 		aclc.hdr.path = SMC_TYPE_D;
581 		aclc.gid = conn->lgr->smcd->local_gid;
582 		aclc.token = conn->rmb_desc->token;
583 		aclc.dmbe_size = conn->rmbe_size_short;
584 		aclc.dmbe_idx = 0;
585 		memcpy(&aclc.linkid, conn->lgr->id, SMC_LGR_ID_SIZE);
586 		memcpy(aclc.smcd_trl.eyecatcher, SMCD_EYECATCHER,
587 		       sizeof(SMCD_EYECATCHER));
588 	} else {
589 		/* SMC-R specific settings */
590 		aclc.hdr.length = htons(SMCR_CLC_ACCEPT_CONFIRM_LEN);
591 		memcpy(aclc.hdr.eyecatcher, SMC_EYECATCHER,
592 		       sizeof(SMC_EYECATCHER));
593 		aclc.hdr.path = SMC_TYPE_R;
594 		link = conn->lnk;
595 		memcpy(aclc.lcl.id_for_peer, local_systemid,
596 		       sizeof(local_systemid));
597 		memcpy(&aclc.lcl.gid, link->gid, SMC_GID_SIZE);
598 		memcpy(&aclc.lcl.mac, link->smcibdev->mac[link->ibport - 1],
599 		       ETH_ALEN);
600 		hton24(aclc.qpn, link->roce_qp->qp_num);
601 		aclc.rmb_rkey =
602 			htonl(conn->rmb_desc->mr_rx[link->link_idx]->rkey);
603 		aclc.rmbe_idx = 1;		/* as long as 1 RMB = 1 RMBE */
604 		aclc.rmbe_alert_token = htonl(conn->alert_token_local);
605 		aclc.qp_mtu = link->path_mtu;
606 		aclc.rmbe_size = conn->rmbe_size_short,
607 		aclc.rmb_dma_addr = cpu_to_be64((u64)sg_dma_address
608 				(conn->rmb_desc->sgt[link->link_idx].sgl));
609 		hton24(aclc.psn, link->psn_initial);
610 		memcpy(aclc.smcr_trl.eyecatcher, SMC_EYECATCHER,
611 		       sizeof(SMC_EYECATCHER));
612 	}
613 
614 	memset(&msg, 0, sizeof(msg));
615 	vec.iov_base = &aclc;
616 	vec.iov_len = ntohs(aclc.hdr.length);
617 	len = kernel_sendmsg(new_smc->clcsock, &msg, &vec, 1,
618 			     ntohs(aclc.hdr.length));
619 	if (len < ntohs(aclc.hdr.length))
620 		len = len >= 0 ? -EPROTO : -new_smc->clcsock->sk->sk_err;
621 
622 	return len > 0 ? 0 : len;
623 }
624