1 files changed, 1177 insertions, 0 deletions

diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
new file mode 100644
index 000000000..9b8999e2a
--- /dev/null
+++ b/net/smc/smc_clc.c
@@ -0,0 +1,1177 @@
+// 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"
+#include "smc_netlink.h"
+
+#define SMCR_CLC_ACCEPT_CONFIRM_LEN 68
+#define SMCD_CLC_ACCEPT_CONFIRM_LEN 48
+#define SMCD_CLC_ACCEPT_CONFIRM_LEN_V2 78
+#define SMCR_CLC_ACCEPT_CONFIRM_LEN_V2 108
+#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];
+
+struct smc_clc_eid_table {
+	rwlock_t lock;
+	struct list_head list;
+	u8 ueid_cnt;
+	u8 seid_enabled;
+};
+
+static struct smc_clc_eid_table smc_clc_eid_table;
+
+struct smc_clc_eid_entry {
+	struct list_head list;
+	u8 eid[SMC_MAX_EID_LEN];
+};
+
+/* The size of a user EID is 32 characters.
+ * Valid characters should be (single-byte character set) A-Z, 0-9, '.' and '-'.
+ * Blanks should only be used to pad to the expected size.
+ * First character must be alphanumeric.
+ */
+static bool smc_clc_ueid_valid(char *ueid)
+{
+	char *end = ueid + SMC_MAX_EID_LEN;
+
+	while (--end >= ueid && isspace(*end))
+		;
+	if (end < ueid)
+		return false;
+	if (!isalnum(*ueid) || islower(*ueid))
+		return false;
+	while (ueid <= end) {
+		if ((!isalnum(*ueid) || islower(*ueid)) && *ueid != '.' &&
+		    *ueid != '-')
+			return false;
+		ueid++;
+	}
+	return true;
+}
+
+static int smc_clc_ueid_add(char *ueid)
+{
+	struct smc_clc_eid_entry *new_ueid, *tmp_ueid;
+	int rc;
+
+	if (!smc_clc_ueid_valid(ueid))
+		return -EINVAL;
+
+	/* add a new ueid entry to the ueid table if there isn't one */
+	new_ueid = kzalloc(sizeof(*new_ueid), GFP_KERNEL);
+	if (!new_ueid)
+		return -ENOMEM;
+	memcpy(new_ueid->eid, ueid, SMC_MAX_EID_LEN);
+
+	write_lock(&smc_clc_eid_table.lock);
+	if (smc_clc_eid_table.ueid_cnt >= SMC_MAX_UEID) {
+		rc = -ERANGE;
+		goto err_out;
+	}
+	list_for_each_entry(tmp_ueid, &smc_clc_eid_table.list, list) {
+		if (!memcmp(tmp_ueid->eid, ueid, SMC_MAX_EID_LEN)) {
+			rc = -EEXIST;
+			goto err_out;
+		}
+	}
+	list_add_tail(&new_ueid->list, &smc_clc_eid_table.list);
+	smc_clc_eid_table.ueid_cnt++;
+	write_unlock(&smc_clc_eid_table.lock);
+	return 0;
+
+err_out:
+	write_unlock(&smc_clc_eid_table.lock);
+	kfree(new_ueid);
+	return rc;
+}
+
+int smc_clc_ueid_count(void)
+{
+	int count;
+
+	read_lock(&smc_clc_eid_table.lock);
+	count = smc_clc_eid_table.ueid_cnt;
+	read_unlock(&smc_clc_eid_table.lock);
+
+	return count;
+}
+
+int smc_nl_add_ueid(struct sk_buff *skb, struct genl_info *info)
+{
+	struct nlattr *nla_ueid = info->attrs[SMC_NLA_EID_TABLE_ENTRY];
+	char *ueid;
+
+	if (!nla_ueid || nla_len(nla_ueid) != SMC_MAX_EID_LEN + 1)
+		return -EINVAL;
+	ueid = (char *)nla_data(nla_ueid);
+
+	return smc_clc_ueid_add(ueid);
+}
+
+/* remove one or all ueid entries from the table */
+static int smc_clc_ueid_remove(char *ueid)
+{
+	struct smc_clc_eid_entry *lst_ueid, *tmp_ueid;
+	int rc = -ENOENT;
+
+	/* remove table entry */
+	write_lock(&smc_clc_eid_table.lock);
+	list_for_each_entry_safe(lst_ueid, tmp_ueid, &smc_clc_eid_table.list,
+				 list) {
+		if (!ueid || !memcmp(lst_ueid->eid, ueid, SMC_MAX_EID_LEN)) {
+			list_del(&lst_ueid->list);
+			smc_clc_eid_table.ueid_cnt--;
+			kfree(lst_ueid);
+			rc = 0;
+		}
+	}
+	if (!rc && !smc_clc_eid_table.ueid_cnt) {
+		smc_clc_eid_table.seid_enabled = 1;
+		rc = -EAGAIN;	/* indicate success and enabling of seid */
+	}
+	write_unlock(&smc_clc_eid_table.lock);
+	return rc;
+}
+
+int smc_nl_remove_ueid(struct sk_buff *skb, struct genl_info *info)
+{
+	struct nlattr *nla_ueid = info->attrs[SMC_NLA_EID_TABLE_ENTRY];
+	char *ueid;
+
+	if (!nla_ueid || nla_len(nla_ueid) != SMC_MAX_EID_LEN + 1)
+		return -EINVAL;
+	ueid = (char *)nla_data(nla_ueid);
+
+	return smc_clc_ueid_remove(ueid);
+}
+
+int smc_nl_flush_ueid(struct sk_buff *skb, struct genl_info *info)
+{
+	smc_clc_ueid_remove(NULL);
+	return 0;
+}
+
+static int smc_nl_ueid_dumpinfo(struct sk_buff *skb, u32 portid, u32 seq,
+				u32 flags, char *ueid)
+{
+	char ueid_str[SMC_MAX_EID_LEN + 1];
+	void *hdr;
+
+	hdr = genlmsg_put(skb, portid, seq, &smc_gen_nl_family,
+			  flags, SMC_NETLINK_DUMP_UEID);
+	if (!hdr)
+		return -ENOMEM;
+	memcpy(ueid_str, ueid, SMC_MAX_EID_LEN);
+	ueid_str[SMC_MAX_EID_LEN] = 0;
+	if (nla_put_string(skb, SMC_NLA_EID_TABLE_ENTRY, ueid_str)) {
+		genlmsg_cancel(skb, hdr);
+		return -EMSGSIZE;
+	}
+	genlmsg_end(skb, hdr);
+	return 0;
+}
+
+static int _smc_nl_ueid_dump(struct sk_buff *skb, u32 portid, u32 seq,
+			     int start_idx)
+{
+	struct smc_clc_eid_entry *lst_ueid;
+	int idx = 0;
+
+	read_lock(&smc_clc_eid_table.lock);
+	list_for_each_entry(lst_ueid, &smc_clc_eid_table.list, list) {
+		if (idx++ < start_idx)
+			continue;
+		if (smc_nl_ueid_dumpinfo(skb, portid, seq, NLM_F_MULTI,
+					 lst_ueid->eid)) {
+			--idx;
+			break;
+		}
+	}
+	read_unlock(&smc_clc_eid_table.lock);
+	return idx;
+}
+
+int smc_nl_dump_ueid(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct smc_nl_dmp_ctx *cb_ctx = smc_nl_dmp_ctx(cb);
+	int idx;
+
+	idx = _smc_nl_ueid_dump(skb, NETLINK_CB(cb->skb).portid,
+				cb->nlh->nlmsg_seq, cb_ctx->pos[0]);
+
+	cb_ctx->pos[0] = idx;
+	return skb->len;
+}
+
+int smc_nl_dump_seid(struct sk_buff *skb, struct netlink_callback *cb)
+{
+	struct smc_nl_dmp_ctx *cb_ctx = smc_nl_dmp_ctx(cb);
+	char seid_str[SMC_MAX_EID_LEN + 1];
+	u8 seid_enabled;
+	void *hdr;
+	u8 *seid;
+
+	if (cb_ctx->pos[0])
+		return skb->len;
+
+	hdr = genlmsg_put(skb, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
+			  &smc_gen_nl_family, NLM_F_MULTI,
+			  SMC_NETLINK_DUMP_SEID);
+	if (!hdr)
+		return -ENOMEM;
+	if (!smc_ism_is_v2_capable())
+		goto end;
+
+	smc_ism_get_system_eid(&seid);
+	memcpy(seid_str, seid, SMC_MAX_EID_LEN);
+	seid_str[SMC_MAX_EID_LEN] = 0;
+	if (nla_put_string(skb, SMC_NLA_SEID_ENTRY, seid_str))
+		goto err;
+	read_lock(&smc_clc_eid_table.lock);
+	seid_enabled = smc_clc_eid_table.seid_enabled;
+	read_unlock(&smc_clc_eid_table.lock);
+	if (nla_put_u8(skb, SMC_NLA_SEID_ENABLED, seid_enabled))
+		goto err;
+end:
+	genlmsg_end(skb, hdr);
+	cb_ctx->pos[0]++;
+	return skb->len;
+err:
+	genlmsg_cancel(skb, hdr);
+	return -EMSGSIZE;
+}
+
+int smc_nl_enable_seid(struct sk_buff *skb, struct genl_info *info)
+{
+	write_lock(&smc_clc_eid_table.lock);
+	smc_clc_eid_table.seid_enabled = 1;
+	write_unlock(&smc_clc_eid_table.lock);
+	return 0;
+}
+
+int smc_nl_disable_seid(struct sk_buff *skb, struct genl_info *info)
+{
+	int rc = 0;
+
+	write_lock(&smc_clc_eid_table.lock);
+	if (!smc_clc_eid_table.ueid_cnt)
+		rc = -ENOENT;
+	else
+		smc_clc_eid_table.seid_enabled = 0;
+	write_unlock(&smc_clc_eid_table.lock);
+	return rc;
+}
+
+static bool _smc_clc_match_ueid(u8 *peer_ueid)
+{
+	struct smc_clc_eid_entry *tmp_ueid;
+
+	list_for_each_entry(tmp_ueid, &smc_clc_eid_table.list, list) {
+		if (!memcmp(tmp_ueid->eid, peer_ueid, SMC_MAX_EID_LEN))
+			return true;
+	}
+	return false;
+}
+
+bool smc_clc_match_eid(u8 *negotiated_eid,
+		       struct smc_clc_v2_extension *smc_v2_ext,
+		       u8 *peer_eid, u8 *local_eid)
+{
+	bool match = false;
+	int i;
+
+	negotiated_eid[0] = 0;
+	read_lock(&smc_clc_eid_table.lock);
+	if (peer_eid && local_eid &&
+	    smc_clc_eid_table.seid_enabled &&
+	    smc_v2_ext->hdr.flag.seid &&
+	    !memcmp(peer_eid, local_eid, SMC_MAX_EID_LEN)) {
+		memcpy(negotiated_eid, peer_eid, SMC_MAX_EID_LEN);
+		match = true;
+		goto out;
+	}
+
+	for (i = 0; i < smc_v2_ext->hdr.eid_cnt; i++) {
+		if (_smc_clc_match_ueid(smc_v2_ext->user_eids[i])) {
+			memcpy(negotiated_eid, smc_v2_ext->user_eids[i],
+			       SMC_MAX_EID_LEN);
+			match = true;
+			goto out;
+		}
+	}
+out:
+	read_unlock(&smc_clc_eid_table.lock);
+	return match;
+}
+
+/* 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;
+		if (hdr->typev1 == SMC_TYPE_R &&
+		    ntohs(hdr->length) < SMCR_CLC_ACCEPT_CONFIRM_LEN_V2)
+			return false;
+	}
+	return true;
+}
+
+/* check arriving CLC decline */
+static bool
+smc_clc_msg_decl_valid(struct smc_clc_msg_decline *dclc)
+{
+	struct smc_clc_msg_hdr *hdr = &dclc->hdr;
+
+	if (hdr->typev1 != SMC_TYPE_R && hdr->typev1 != SMC_TYPE_D)
+		return false;
+	if (hdr->version == SMC_V1) {
+		if (ntohs(hdr->length) != sizeof(struct smc_clc_msg_decline))
+			return false;
+	} else {
+		if (ntohs(hdr->length) != sizeof(struct smc_clc_msg_decline_v2))
+			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 (!smc_clc_msg_decl_valid(dclc))
+			return false;
+		check_trl = false;
+		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, ITER_DEST, &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, ITER_DEST, &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, ITER_DEST, &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_v1;
+	struct smc_clc_msg_decline_v2 dclc;
+	struct msghdr msg;
+	int len, send_len;
+	struct kvec vec;
+
+	dclc_v1 = (struct smc_clc_msg_decline *)&dclc;
+	memset(&dclc, 0, sizeof(dclc));
+	memcpy(dclc.hdr.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
+	dclc.hdr.type = SMC_CLC_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_valid(&smc->conn) || !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);
+	if (version == SMC_V1) {
+		memcpy(dclc_v1->trl.eyecatcher, SMC_EYECATCHER,
+		       sizeof(SMC_EYECATCHER));
+		send_len = sizeof(*dclc_v1);
+	} else {
+		memcpy(dclc.trl.eyecatcher, SMC_EYECATCHER,
+		       sizeof(SMC_EYECATCHER));
+		send_len = sizeof(dclc);
+	}
+	dclc.hdr.length = htons(send_len);
+
+	memset(&msg, 0, sizeof(msg));
+	vec.iov_base = &dclc;
+	vec.iov_len = send_len;
+	len = kernel_sendmsg(smc->clcsock, &msg, &vec, 1, send_len);
+	if (len < 0 || len < send_len)
+		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 {
+		struct smc_clc_eid_entry *ueident;
+		u16 v2_ext_offset;
+
+		v2_ext->hdr.flag.release = SMC_RELEASE;
+		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);
+		plen += sizeof(*v2_ext);
+
+		read_lock(&smc_clc_eid_table.lock);
+		v2_ext->hdr.eid_cnt = smc_clc_eid_table.ueid_cnt;
+		plen += smc_clc_eid_table.ueid_cnt * SMC_MAX_EID_LEN;
+		i = 0;
+		list_for_each_entry(ueident, &smc_clc_eid_table.list, list) {
+			memcpy(v2_ext->user_eids[i++], ueident->eid,
+			       sizeof(ueident->eid));
+		}
+		read_unlock(&smc_clc_eid_table.lock);
+	}
+	if (smcd_indicated(ini->smc_type_v2)) {
+		u8 *eid = NULL;
+
+		v2_ext->hdr.flag.seid = smc_clc_eid_table.seid_enabled;
+		v2_ext->hdr.ism_gid_cnt = ini->ism_offered_cnt;
+		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);
+		smc_ism_get_system_eid(&eid);
+		if (eid && v2_ext->hdr.flag.seid)
+			memcpy(smcd_v2_ext->system_eid, eid, SMC_MAX_EID_LEN);
+		plen += 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);
+		}
+	}
+	if (smcr_indicated(ini->smc_type_v2))
+		memcpy(v2_ext->roce, ini->smcrv2.ib_gid_v2, SMC_GID_SIZE);
+
+	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) +
+				   (v2_ext->hdr.eid_cnt * SMC_MAX_EID_LEN);
+		if (smcd_indicated(ini->smc_type_v2)) {
+			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,
+				       u8 *eid, struct smc_init_info *ini)
+{
+	struct smc_connection *conn = &smc->conn;
+	struct smc_clc_msg_accept_confirm *clc;
+	struct smc_clc_first_contact_ext fce;
+	struct smc_clc_fce_gid_ext gle;
+	struct smc_clc_msg_trail trl;
+	struct kvec vec[5];
+	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_comp;
+		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 {
+			clc_v2->d1.chid =
+				htons(smc_ism_get_chid(conn->lgr->smcd));
+			if (eid && eid[0])
+				memcpy(clc_v2->d1.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 */
+		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[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_comp;
+		clc->r0.rmb_dma_addr = conn->rmb_desc->is_vm ?
+			cpu_to_be64((uintptr_t)conn->rmb_desc->cpu_addr) :
+			cpu_to_be64((u64)sg_dma_address
+				    (conn->rmb_desc->sgt[link->link_idx].sgl));
+		hton24(clc->r0.psn, link->psn_initial);
+		if (version == SMC_V1) {
+			clc->hdr.length = htons(SMCR_CLC_ACCEPT_CONFIRM_LEN);
+		} else {
+			if (eid && eid[0])
+				memcpy(clc_v2->r1.eid, eid, SMC_MAX_EID_LEN);
+			len = SMCR_CLC_ACCEPT_CONFIRM_LEN_V2;
+			if (first_contact) {
+				smc_clc_fill_fce(&fce, &len);
+				fce.v2_direct = !link->lgr->uses_gateway;
+				memset(&gle, 0, sizeof(gle));
+				if (ini && clc->hdr.type == SMC_CLC_CONFIRM) {
+					gle.gid_cnt = ini->smcrv2.gidlist.len;
+					len += sizeof(gle);
+					len += gle.gid_cnt * sizeof(gle.gid[0]);
+				} else {
+					len += sizeof(gle.reserved);
+				}
+			}
+			clc_v2->hdr.length = htons(len);
+		}
+		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 = (clc->hdr.typev1 == SMC_TYPE_D ?
+					SMCD_CLC_ACCEPT_CONFIRM_LEN_V2 :
+					SMCR_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);
+		if (!conn->lgr->is_smcd) {
+			if (clc->hdr.type == SMC_CLC_CONFIRM) {
+				vec[i].iov_base = &gle;
+				vec[i++].iov_len = sizeof(gle);
+				vec[i].iov_base = &ini->smcrv2.gidlist.list;
+				vec[i++].iov_len = gle.gid_cnt *
+						   sizeof(gle.gid[0]);
+			} else {
+				vec[i].iov_base = &gle.reserved;
+				vec[i++].iov_len = sizeof(gle.reserved);
+			}
+		}
+	}
+	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, u8 *eid, struct smc_init_info *ini)
+{
+	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, eid, ini);
+	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, u8 *negotiated_eid)
+{
+	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, negotiated_eid, NULL);
+	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)));
+
+	INIT_LIST_HEAD(&smc_clc_eid_table.list);
+	rwlock_init(&smc_clc_eid_table.lock);
+	smc_clc_eid_table.ueid_cnt = 0;
+	smc_clc_eid_table.seid_enabled = 1;
+}
+
+void smc_clc_exit(void)
+{
+	smc_clc_ueid_remove(NULL);
+}