net/smc/smc_clc.c - kernel/msm-5.4 - Gitiles

 // 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
  *
  *  Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
  */

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

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

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

 /* 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)
 {
 	struct smc_clc_msg_proposal_prefix *pclc_prfx;
 	struct smc_clc_msg_accept_confirm *clc;
 	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)))
 		return false;
 	switch (clcm->type) {
 	case SMC_CLC_PROPOSAL:
 		pclc = (struct smc_clc_msg_proposal *)clcm;
 		pclc_prfx = smc_clc_proposal_get_prefix(pclc);
 		if (ntohs(pclc->hdr.length) !=
 			sizeof(*pclc) + ntohs(pclc->iparea_offset) +
 			sizeof(*pclc_prfx) +
 			pclc_prfx->ipv6_prefixes_cnt *
 				sizeof(struct smc_clc_ipv6_prefix) +
 			sizeof(*trl))
 			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 = (struct smc_clc_msg_accept_confirm *)clcm;
 		if (ntohs(clc->hdr.length) != sizeof(*clc))
 			return false;
 		trl = &clc->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 (memcmp(trl->eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER)))
 		return false;
 	return true;
 }

 /* 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)
 {
 	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;
 	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;
 	smc->clcsock->sk->sk_rcvtimeo = CLC_WAIT_TIME;
 	iov_iter_kvec(&msg.msg_iter, READ | ITER_KVEC, &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;
 		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) {
 		smc->sk.sk_err = -len;
 		reason_code = len;
 		goto out;
 	}
 	datlen = ntohs(clcm->length);
 	if ((len < sizeof(struct smc_clc_msg_hdr)) ||
 	    (datlen > buflen) ||
 	    ((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));
 	iov_iter_kvec(&msg.msg_iter, READ | ITER_KVEC, &vec, 1, buflen);
 	krflags = MSG_WAITALL;
 	smc->clcsock->sk->sk_rcvtimeo = CLC_WAIT_TIME;
 	len = sock_recvmsg(smc->clcsock, &msg, krflags);
 	if (len < datlen || !smc_clc_msg_hdr_valid(clcm)) {
 		smc->sk.sk_err = EPROTO;
 		reason_code = -EPROTO;
 		goto out;
 	}
 	if (clcm->type == SMC_CLC_DECLINE) {
 		reason_code = SMC_CLC_DECL_REPLY;
 		if (((struct smc_clc_msg_decline *)buf)->hdr.flag) {
 			smc->conn.lgr->sync_err = true;
 			smc_lgr_terminate(smc->conn.lgr);
 		}
 	}

 out:
 	return reason_code;
 }

 /* send CLC DECLINE message across internal TCP socket */
 int smc_clc_send_decline(struct smc_sock *smc, u32 peer_diag_info)
 {
 	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 = SMC_CLC_V1;
 	dclc.hdr.flag = (peer_diag_info == SMC_CLC_DECL_SYNCERR) ? 1 : 0;
 	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 < sizeof(struct smc_clc_msg_decline))
 		smc->sk.sk_err = EPROTO;
 	if (len < 0)
 		smc->sk.sk_err = -len;
 	return sock_error(&smc->sk);
 }

 /* send CLC PROPOSAL message across internal TCP socket */
 int smc_clc_send_proposal(struct smc_sock *smc,
 			  struct smc_ib_device *smcibdev,
 			  u8 ibport)
 {
 	struct smc_clc_msg_proposal_prefix pclc_prfx;
 	struct smc_clc_msg_proposal pclc;
 	struct smc_clc_msg_trail trl;
 	int reason_code = 0;
 	struct kvec vec[3];
 	struct msghdr msg;
 	int len, plen, rc;

 	/* send SMC Proposal CLC message */
 	plen = sizeof(pclc) + sizeof(pclc_prfx) + sizeof(trl);
 	memset(&pclc, 0, sizeof(pclc));
 	memcpy(pclc.hdr.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
 	pclc.hdr.type = SMC_CLC_PROPOSAL;
 	pclc.hdr.length = htons(plen);
 	pclc.hdr.version = SMC_CLC_V1;		/* SMC version */
 	memcpy(pclc.lcl.id_for_peer, local_systemid, sizeof(local_systemid));
 	memcpy(&pclc.lcl.gid, &smcibdev->gid[ibport - 1], SMC_GID_SIZE);
 	memcpy(&pclc.lcl.mac, &smcibdev->mac[ibport - 1], ETH_ALEN);
 	pclc.iparea_offset = htons(0);

 	memset(&pclc_prfx, 0, sizeof(pclc_prfx));
 	/* determine subnet and mask from internal TCP socket */
 	rc = smc_netinfo_by_tcpsk(smc->clcsock, &pclc_prfx.outgoing_subnet,
 				  &pclc_prfx.prefix_len);
 	if (rc)
 		return SMC_CLC_DECL_CNFERR; /* configuration error */
 	pclc_prfx.ipv6_prefixes_cnt = 0;
 	memcpy(trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
 	memset(&msg, 0, sizeof(msg));
 	vec[0].iov_base = &pclc;
 	vec[0].iov_len = sizeof(pclc);
 	vec[1].iov_base = &pclc_prfx;
 	vec[1].iov_len = sizeof(pclc_prfx);
 	vec[2].iov_base = &trl;
 	vec[2].iov_len = sizeof(trl);
 	/* due to the few bytes needed for clc-handshake this cannot block */
 	len = kernel_sendmsg(smc->clcsock, &msg, vec, 3, plen);
 	if (len < sizeof(pclc)) {
 		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 CONFIRM message across internal TCP socket */
 int smc_clc_send_confirm(struct smc_sock *smc)
 {
 	struct smc_connection *conn = &smc->conn;
 	struct smc_clc_msg_accept_confirm cclc;
 	struct smc_link *link;
 	int reason_code = 0;
 	struct msghdr msg;
 	struct kvec vec;
 	int len;

 	link = &conn->lgr->lnk[SMC_SINGLE_LINK];
 	/* send SMC Confirm CLC msg */
 	memset(&cclc, 0, sizeof(cclc));
 	memcpy(cclc.hdr.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
 	cclc.hdr.type = SMC_CLC_CONFIRM;
 	cclc.hdr.length = htons(sizeof(cclc));
 	cclc.hdr.version = SMC_CLC_V1;		/* SMC version */
 	memcpy(cclc.lcl.id_for_peer, local_systemid, sizeof(local_systemid));
 	memcpy(&cclc.lcl.gid, &link->smcibdev->gid[link->ibport - 1],
 	       SMC_GID_SIZE);
 	memcpy(&cclc.lcl.mac, &link->smcibdev->mac[link->ibport - 1], ETH_ALEN);
 	hton24(cclc.qpn, link->roce_qp->qp_num);
 	cclc.rmb_rkey =
 		htonl(conn->rmb_desc->mr_rx[SMC_SINGLE_LINK]->rkey);
 	cclc.conn_idx = 1; /* for now: 1 RMB = 1 RMBE */
 	cclc.rmbe_alert_token = htonl(conn->alert_token_local);
 	cclc.qp_mtu = min(link->path_mtu, link->peer_mtu);
 	cclc.rmbe_size = conn->rmbe_size_short;
 	cclc.rmb_dma_addr = cpu_to_be64(
 		(u64)sg_dma_address(conn->rmb_desc->sgt[SMC_SINGLE_LINK].sgl));
 	hton24(cclc.psn, link->psn_initial);

 	memcpy(cclc.trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));

 	memset(&msg, 0, sizeof(msg));
 	vec.iov_base = &cclc;
 	vec.iov_len = sizeof(cclc);
 	len = kernel_sendmsg(smc->clcsock, &msg, &vec, 1, sizeof(cclc));
 	if (len < sizeof(cclc)) {
 		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, int srv_first_contact)
 {
 	struct smc_connection *conn = &new_smc->conn;
 	struct smc_clc_msg_accept_confirm aclc;
 	struct smc_link *link;
 	struct msghdr msg;
 	struct kvec vec;
 	int rc = 0;
 	int len;

 	link = &conn->lgr->lnk[SMC_SINGLE_LINK];
 	memset(&aclc, 0, sizeof(aclc));
 	memcpy(aclc.hdr.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
 	aclc.hdr.type = SMC_CLC_ACCEPT;
 	aclc.hdr.length = htons(sizeof(aclc));
 	aclc.hdr.version = SMC_CLC_V1;		/* SMC version */
 	if (srv_first_contact)
 		aclc.hdr.flag = 1;
 	memcpy(aclc.lcl.id_for_peer, local_systemid, sizeof(local_systemid));
 	memcpy(&aclc.lcl.gid, &link->smcibdev->gid[link->ibport - 1],
 	       SMC_GID_SIZE);
 	memcpy(&aclc.lcl.mac, link->smcibdev->mac[link->ibport - 1], ETH_ALEN);
 	hton24(aclc.qpn, link->roce_qp->qp_num);
 	aclc.rmb_rkey =
 		htonl(conn->rmb_desc->mr_rx[SMC_SINGLE_LINK]->rkey);
 	aclc.conn_idx = 1;			/* as long as 1 RMB = 1 RMBE */
 	aclc.rmbe_alert_token = htonl(conn->alert_token_local);
 	aclc.qp_mtu = link->path_mtu;
 	aclc.rmbe_size = conn->rmbe_size_short,
 	aclc.rmb_dma_addr = cpu_to_be64(
 		(u64)sg_dma_address(conn->rmb_desc->sgt[SMC_SINGLE_LINK].sgl));
 	hton24(aclc.psn, link->psn_initial);
 	memcpy(aclc.trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));

 	memset(&msg, 0, sizeof(msg));
 	vec.iov_base = &aclc;
 	vec.iov_len = sizeof(aclc);
 	len = kernel_sendmsg(new_smc->clcsock, &msg, &vec, 1, sizeof(aclc));
 	if (len < sizeof(aclc)) {
 		if (len >= 0)
 			new_smc->sk.sk_err = EPROTO;
 		else
 			new_smc->sk.sk_err = new_smc->clcsock->sk->sk_err;
 		rc = sock_error(&new_smc->sk);
 	}

 	return rc;
 }
	// 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
	*
	* Author(s): Ursula Braun <ubraun@linux.vnet.ibm.com>
	*/

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

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

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

	/* 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)
	{
	struct smc_clc_msg_proposal_prefix *pclc_prfx;
	struct smc_clc_msg_accept_confirm *clc;
	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)))
	return false;
	switch (clcm->type) {
	case SMC_CLC_PROPOSAL:
	pclc = (struct smc_clc_msg_proposal *)clcm;
	pclc_prfx = smc_clc_proposal_get_prefix(pclc);
	if (ntohs(pclc->hdr.length) !=
	sizeof(*pclc) + ntohs(pclc->iparea_offset) +
	sizeof(*pclc_prfx) +
	pclc_prfx->ipv6_prefixes_cnt *
	sizeof(struct smc_clc_ipv6_prefix) +
	sizeof(*trl))
	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 = (struct smc_clc_msg_accept_confirm *)clcm;
	if (ntohs(clc->hdr.length) != sizeof(*clc))
	return false;
	trl = &clc->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 (memcmp(trl->eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER)))
	return false;
	return true;
	}

	/* 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)
	{
	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;
	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;
	smc->clcsock->sk->sk_rcvtimeo = CLC_WAIT_TIME;
	iov_iter_kvec(&msg.msg_iter, READ \| ITER_KVEC, &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;
	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) {
	smc->sk.sk_err = -len;
	reason_code = len;
	goto out;
	}
	datlen = ntohs(clcm->length);
	if ((len < sizeof(struct smc_clc_msg_hdr)) \|\|
	(datlen > buflen) \|\|
	((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));
	iov_iter_kvec(&msg.msg_iter, READ \| ITER_KVEC, &vec, 1, buflen);
	krflags = MSG_WAITALL;
	smc->clcsock->sk->sk_rcvtimeo = CLC_WAIT_TIME;
	len = sock_recvmsg(smc->clcsock, &msg, krflags);
	if (len < datlen \|\| !smc_clc_msg_hdr_valid(clcm)) {
	smc->sk.sk_err = EPROTO;
	reason_code = -EPROTO;
	goto out;
	}
	if (clcm->type == SMC_CLC_DECLINE) {
	reason_code = SMC_CLC_DECL_REPLY;
	if (((struct smc_clc_msg_decline *)buf)->hdr.flag) {
	smc->conn.lgr->sync_err = true;
	smc_lgr_terminate(smc->conn.lgr);
	}
	}

	out:
	return reason_code;
	}

	/* send CLC DECLINE message across internal TCP socket */
	int smc_clc_send_decline(struct smc_sock *smc, u32 peer_diag_info)
	{
	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 = SMC_CLC_V1;
	dclc.hdr.flag = (peer_diag_info == SMC_CLC_DECL_SYNCERR) ? 1 : 0;
	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 < sizeof(struct smc_clc_msg_decline))
	smc->sk.sk_err = EPROTO;
	if (len < 0)
	smc->sk.sk_err = -len;
	return sock_error(&smc->sk);
	}

	/* send CLC PROPOSAL message across internal TCP socket */
	int smc_clc_send_proposal(struct smc_sock *smc,
	struct smc_ib_device *smcibdev,
	u8 ibport)
	{
	struct smc_clc_msg_proposal_prefix pclc_prfx;
	struct smc_clc_msg_proposal pclc;
	struct smc_clc_msg_trail trl;
	int reason_code = 0;
	struct kvec vec[3];
	struct msghdr msg;
	int len, plen, rc;

	/* send SMC Proposal CLC message */
	plen = sizeof(pclc) + sizeof(pclc_prfx) + sizeof(trl);
	memset(&pclc, 0, sizeof(pclc));
	memcpy(pclc.hdr.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
	pclc.hdr.type = SMC_CLC_PROPOSAL;
	pclc.hdr.length = htons(plen);
	pclc.hdr.version = SMC_CLC_V1; /* SMC version */
	memcpy(pclc.lcl.id_for_peer, local_systemid, sizeof(local_systemid));
	memcpy(&pclc.lcl.gid, &smcibdev->gid[ibport - 1], SMC_GID_SIZE);
	memcpy(&pclc.lcl.mac, &smcibdev->mac[ibport - 1], ETH_ALEN);
	pclc.iparea_offset = htons(0);

	memset(&pclc_prfx, 0, sizeof(pclc_prfx));
	/* determine subnet and mask from internal TCP socket */
	rc = smc_netinfo_by_tcpsk(smc->clcsock, &pclc_prfx.outgoing_subnet,
	&pclc_prfx.prefix_len);
	if (rc)
	return SMC_CLC_DECL_CNFERR; /* configuration error */
	pclc_prfx.ipv6_prefixes_cnt = 0;
	memcpy(trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
	memset(&msg, 0, sizeof(msg));
	vec[0].iov_base = &pclc;
	vec[0].iov_len = sizeof(pclc);
	vec[1].iov_base = &pclc_prfx;
	vec[1].iov_len = sizeof(pclc_prfx);
	vec[2].iov_base = &trl;
	vec[2].iov_len = sizeof(trl);
	/* due to the few bytes needed for clc-handshake this cannot block */
	len = kernel_sendmsg(smc->clcsock, &msg, vec, 3, plen);
	if (len < sizeof(pclc)) {
	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 CONFIRM message across internal TCP socket */
	int smc_clc_send_confirm(struct smc_sock *smc)
	{
	struct smc_connection *conn = &smc->conn;
	struct smc_clc_msg_accept_confirm cclc;
	struct smc_link *link;
	int reason_code = 0;
	struct msghdr msg;
	struct kvec vec;
	int len;

	link = &conn->lgr->lnk[SMC_SINGLE_LINK];
	/* send SMC Confirm CLC msg */
	memset(&cclc, 0, sizeof(cclc));
	memcpy(cclc.hdr.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
	cclc.hdr.type = SMC_CLC_CONFIRM;
	cclc.hdr.length = htons(sizeof(cclc));
	cclc.hdr.version = SMC_CLC_V1; /* SMC version */
	memcpy(cclc.lcl.id_for_peer, local_systemid, sizeof(local_systemid));
	memcpy(&cclc.lcl.gid, &link->smcibdev->gid[link->ibport - 1],
	SMC_GID_SIZE);
	memcpy(&cclc.lcl.mac, &link->smcibdev->mac[link->ibport - 1], ETH_ALEN);
	hton24(cclc.qpn, link->roce_qp->qp_num);
	cclc.rmb_rkey =
	htonl(conn->rmb_desc->mr_rx[SMC_SINGLE_LINK]->rkey);
	cclc.conn_idx = 1; /* for now: 1 RMB = 1 RMBE */
	cclc.rmbe_alert_token = htonl(conn->alert_token_local);
	cclc.qp_mtu = min(link->path_mtu, link->peer_mtu);
	cclc.rmbe_size = conn->rmbe_size_short;
	cclc.rmb_dma_addr = cpu_to_be64(
	(u64)sg_dma_address(conn->rmb_desc->sgt[SMC_SINGLE_LINK].sgl));
	hton24(cclc.psn, link->psn_initial);

	memcpy(cclc.trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));

	memset(&msg, 0, sizeof(msg));
	vec.iov_base = &cclc;
	vec.iov_len = sizeof(cclc);
	len = kernel_sendmsg(smc->clcsock, &msg, &vec, 1, sizeof(cclc));
	if (len < sizeof(cclc)) {
	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, int srv_first_contact)
	{
	struct smc_connection *conn = &new_smc->conn;
	struct smc_clc_msg_accept_confirm aclc;
	struct smc_link *link;
	struct msghdr msg;
	struct kvec vec;
	int rc = 0;
	int len;

	link = &conn->lgr->lnk[SMC_SINGLE_LINK];
	memset(&aclc, 0, sizeof(aclc));
	memcpy(aclc.hdr.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
	aclc.hdr.type = SMC_CLC_ACCEPT;
	aclc.hdr.length = htons(sizeof(aclc));
	aclc.hdr.version = SMC_CLC_V1; /* SMC version */
	if (srv_first_contact)
	aclc.hdr.flag = 1;
	memcpy(aclc.lcl.id_for_peer, local_systemid, sizeof(local_systemid));
	memcpy(&aclc.lcl.gid, &link->smcibdev->gid[link->ibport - 1],
	SMC_GID_SIZE);
	memcpy(&aclc.lcl.mac, link->smcibdev->mac[link->ibport - 1], ETH_ALEN);
	hton24(aclc.qpn, link->roce_qp->qp_num);
	aclc.rmb_rkey =
	htonl(conn->rmb_desc->mr_rx[SMC_SINGLE_LINK]->rkey);
	aclc.conn_idx = 1; /* as long as 1 RMB = 1 RMBE */
	aclc.rmbe_alert_token = htonl(conn->alert_token_local);
	aclc.qp_mtu = link->path_mtu;
	aclc.rmbe_size = conn->rmbe_size_short,
	aclc.rmb_dma_addr = cpu_to_be64(
	(u64)sg_dma_address(conn->rmb_desc->sgt[SMC_SINGLE_LINK].sgl));
	hton24(aclc.psn, link->psn_initial);
	memcpy(aclc.trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));

	memset(&msg, 0, sizeof(msg));
	vec.iov_base = &aclc;
	vec.iov_len = sizeof(aclc);
	len = kernel_sendmsg(new_smc->clcsock, &msg, &vec, 1, sizeof(aclc));
	if (len < sizeof(aclc)) {
	if (len >= 0)
	new_smc->sk.sk_err = EPROTO;
	else
	new_smc->sk.sk_err = new_smc->clcsock->sk->sk_err;
	rc = sock_error(&new_smc->sk);
	}

	return rc;
	}