RDMA/core: Add support for iWARP Port Mapper user space service

This patch adds iWARP Port Mapper (IWPM) Version 2 support.  The iWARP
Port Mapper implementation is based on the port mapper specification
section in the Sockets Direct Protocol paper -
http://www.rdmaconsortium.org/home/draft-pinkerton-iwarp-sdp-v1.0.pdf

Existing iWARP RDMA providers use the same IP address as the native
TCP/IP stack when creating RDMA connections.  They need a mechanism to
claim the TCP ports used for RDMA connections to prevent TCP port
collisions when other host applications use TCP ports.  The iWARP Port
Mapper provides a standard mechanism to accomplish this.  Without this
service it is possible for RDMA application to bind/listen on the same
port which is already being used by native TCP host application.  If
that happens the incoming TCP connection data can be passed to the
RDMA stack with error.

The iWARP Port Mapper solution doesn't contain any changes to the
existing network stack in the kernel space.  All the changes are
contained with the infiniband tree and also in user space.

The iWARP Port Mapper service is implemented as a user space daemon
process.  Source for the IWPM service is located at
http://git.openfabrics.org/git?p=~tnikolova/libiwpm-1.0.0/.git;a=summary

The iWARP driver (port mapper client) sends to the IWPM service the
local IP address and TCP port it has received from the RDMA
application, when starting a connection.  The IWPM service performs a
socket bind from user space to get an available TCP port, called a
mapped port, and communicates it back to the client.  In that sense,
the IWPM service is used to map the TCP port, which the RDMA
application uses to any port available from the host TCP port
space. The mapped ports are used in iWARP RDMA connections to avoid
collisions with native TCP stack which is aware that these ports are
taken. When an RDMA connection using a mapped port is terminated, the
client notifies the IWPM service, which then releases the TCP port.

The message exchange between the IWPM service and the iWARP drivers
(between user space and kernel space) is implemented using netlink
sockets.

1) Netlink interface functions are added: ibnl_unicast() and
   ibnl_mulitcast() for sending netlink messages to user space

2) The signature of the existing ibnl_put_msg() is changed to be more
   generic

3) Two netlink clients are added: RDMA_NL_NES, RDMA_NL_C4IW
   corresponding to the two iWarp drivers - nes and cxgb4 which use
   the IWPM service

4) Enums are added to enumerate the attributes in the netlink
   messages, which are exchanged between the user space IWPM service
   and the iWARP drivers

Signed-off-by: Tatyana Nikolova <tatyana.e.nikolova@intel.com>
Signed-off-by: Steve Wise <swise@opengridcomputing.com>
Reviewed-by: PJ Waskiewicz <pj.waskiewicz@solidfire.com>

[ Fold in range checking fixes and nlh_next removal as suggested by Dan
  Carpenter and Steve Wise.  Fix sparse endianness in hash.  - Roland ]

Signed-off-by: Roland Dreier <roland@purestorage.com>

1 files changed, 607 insertions, 0 deletions

diff --git a/drivers/infiniband/core/iwpm_util.c b/drivers/infiniband/core/iwpm_util.c
new file mode 100644
index 0000000..69e9f84
--- /dev/null
+++ b/drivers/infiniband/core/iwpm_util.c
@@ -0,0 +1,607 @@
+/*
+ * Copyright (c) 2014 Chelsio, Inc. All rights reserved.
+ * Copyright (c) 2014 Intel Corporation. All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *	  copyright notice, this list of conditions and the following
+ *	  disclaimer.
+ *
+ *      - Redistributions in binary form must reproduce the above
+ *	  copyright notice, this list of conditions and the following
+ *	  disclaimer in the documentation and/or other materials
+ *	  provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#include "iwpm_util.h"
+
+#define IWPM_HASH_BUCKET_SIZE	512
+#define IWPM_HASH_BUCKET_MASK	(IWPM_HASH_BUCKET_SIZE - 1)
+
+static LIST_HEAD(iwpm_nlmsg_req_list);
+static DEFINE_SPINLOCK(iwpm_nlmsg_req_lock);
+
+static struct hlist_head *iwpm_hash_bucket;
+static DEFINE_SPINLOCK(iwpm_mapinfo_lock);
+
+static DEFINE_MUTEX(iwpm_admin_lock);
+static struct iwpm_admin_data iwpm_admin;
+
+int iwpm_init(u8 nl_client)
+{
+	if (iwpm_valid_client(nl_client))
+		return -EINVAL;
+	mutex_lock(&iwpm_admin_lock);
+	if (atomic_read(&iwpm_admin.refcount) == 0) {
+		iwpm_hash_bucket = kzalloc(IWPM_HASH_BUCKET_SIZE *
+					sizeof(struct hlist_head), GFP_KERNEL);
+		if (!iwpm_hash_bucket) {
+			mutex_unlock(&iwpm_admin_lock);
+			pr_err("%s Unable to create mapinfo hash table\n", __func__);
+			return -ENOMEM;
+		}
+	}
+	atomic_inc(&iwpm_admin.refcount);
+	mutex_unlock(&iwpm_admin_lock);
+	iwpm_set_valid(nl_client, 1);
+	return 0;
+}
+EXPORT_SYMBOL(iwpm_init);
+
+static void free_hash_bucket(void);
+
+int iwpm_exit(u8 nl_client)
+{
+
+	if (!iwpm_valid_client(nl_client))
+		return -EINVAL;
+	mutex_lock(&iwpm_admin_lock);
+	if (atomic_read(&iwpm_admin.refcount) == 0) {
+		mutex_unlock(&iwpm_admin_lock);
+		pr_err("%s Incorrect usage - negative refcount\n", __func__);
+		return -EINVAL;
+	}
+	if (atomic_dec_and_test(&iwpm_admin.refcount)) {
+		free_hash_bucket();
+		pr_debug("%s: Mapinfo hash table is destroyed\n", __func__);
+	}
+	mutex_unlock(&iwpm_admin_lock);
+	iwpm_set_valid(nl_client, 0);
+	return 0;
+}
+EXPORT_SYMBOL(iwpm_exit);
+
+static struct hlist_head *get_hash_bucket_head(struct sockaddr_storage *,
+					       struct sockaddr_storage *);
+
+int iwpm_create_mapinfo(struct sockaddr_storage *local_sockaddr,
+			struct sockaddr_storage *mapped_sockaddr,
+			u8 nl_client)
+{
+	struct hlist_head *hash_bucket_head;
+	struct iwpm_mapping_info *map_info;
+	unsigned long flags;
+
+	if (!iwpm_valid_client(nl_client))
+		return -EINVAL;
+	map_info = kzalloc(sizeof(struct iwpm_mapping_info), GFP_KERNEL);
+	if (!map_info) {
+		pr_err("%s: Unable to allocate a mapping info\n", __func__);
+		return -ENOMEM;
+	}
+	memcpy(&map_info->local_sockaddr, local_sockaddr,
+	       sizeof(struct sockaddr_storage));
+	memcpy(&map_info->mapped_sockaddr, mapped_sockaddr,
+	       sizeof(struct sockaddr_storage));
+	map_info->nl_client = nl_client;
+
+	spin_lock_irqsave(&iwpm_mapinfo_lock, flags);
+	if (iwpm_hash_bucket) {
+		hash_bucket_head = get_hash_bucket_head(
+					&map_info->local_sockaddr,
+					&map_info->mapped_sockaddr);
+		hlist_add_head(&map_info->hlist_node, hash_bucket_head);
+	}
+	spin_unlock_irqrestore(&iwpm_mapinfo_lock, flags);
+	return 0;
+}
+EXPORT_SYMBOL(iwpm_create_mapinfo);
+
+int iwpm_remove_mapinfo(struct sockaddr_storage *local_sockaddr,
+			struct sockaddr_storage *mapped_local_addr)
+{
+	struct hlist_node *tmp_hlist_node;
+	struct hlist_head *hash_bucket_head;
+	struct iwpm_mapping_info *map_info = NULL;
+	unsigned long flags;
+	int ret = -EINVAL;
+
+	spin_lock_irqsave(&iwpm_mapinfo_lock, flags);
+	if (iwpm_hash_bucket) {
+		hash_bucket_head = get_hash_bucket_head(
+					local_sockaddr,
+					mapped_local_addr);
+		hlist_for_each_entry_safe(map_info, tmp_hlist_node,
+					hash_bucket_head, hlist_node) {
+
+			if (!iwpm_compare_sockaddr(&map_info->mapped_sockaddr,
+						mapped_local_addr)) {
+
+				hlist_del_init(&map_info->hlist_node);
+				kfree(map_info);
+				ret = 0;
+				break;
+			}
+		}
+	}
+	spin_unlock_irqrestore(&iwpm_mapinfo_lock, flags);
+	return ret;
+}
+EXPORT_SYMBOL(iwpm_remove_mapinfo);
+
+static void free_hash_bucket(void)
+{
+	struct hlist_node *tmp_hlist_node;
+	struct iwpm_mapping_info *map_info;
+	unsigned long flags;
+	int i;
+
+	/* remove all the mapinfo data from the list */
+	spin_lock_irqsave(&iwpm_mapinfo_lock, flags);
+	for (i = 0; i < IWPM_HASH_BUCKET_SIZE; i++) {
+		hlist_for_each_entry_safe(map_info, tmp_hlist_node,
+			&iwpm_hash_bucket[i], hlist_node) {
+
+				hlist_del_init(&map_info->hlist_node);
+				kfree(map_info);
+			}
+	}
+	/* free the hash list */
+	kfree(iwpm_hash_bucket);
+	iwpm_hash_bucket = NULL;
+	spin_unlock_irqrestore(&iwpm_mapinfo_lock, flags);
+}
+
+struct iwpm_nlmsg_request *iwpm_get_nlmsg_request(__u32 nlmsg_seq,
+					u8 nl_client, gfp_t gfp)
+{
+	struct iwpm_nlmsg_request *nlmsg_request = NULL;
+	unsigned long flags;
+
+	nlmsg_request = kzalloc(sizeof(struct iwpm_nlmsg_request), gfp);
+	if (!nlmsg_request) {
+		pr_err("%s Unable to allocate a nlmsg_request\n", __func__);
+		return NULL;
+	}
+	spin_lock_irqsave(&iwpm_nlmsg_req_lock, flags);
+	list_add_tail(&nlmsg_request->inprocess_list, &iwpm_nlmsg_req_list);
+	spin_unlock_irqrestore(&iwpm_nlmsg_req_lock, flags);
+
+	kref_init(&nlmsg_request->kref);
+	kref_get(&nlmsg_request->kref);
+	nlmsg_request->nlmsg_seq = nlmsg_seq;
+	nlmsg_request->nl_client = nl_client;
+	nlmsg_request->request_done = 0;
+	nlmsg_request->err_code = 0;
+	return nlmsg_request;
+}
+
+void iwpm_free_nlmsg_request(struct kref *kref)
+{
+	struct iwpm_nlmsg_request *nlmsg_request;
+	unsigned long flags;
+
+	nlmsg_request = container_of(kref, struct iwpm_nlmsg_request, kref);
+
+	spin_lock_irqsave(&iwpm_nlmsg_req_lock, flags);
+	list_del_init(&nlmsg_request->inprocess_list);
+	spin_unlock_irqrestore(&iwpm_nlmsg_req_lock, flags);
+
+	if (!nlmsg_request->request_done)
+		pr_debug("%s Freeing incomplete nlmsg request (seq = %u).\n",
+			__func__, nlmsg_request->nlmsg_seq);
+	kfree(nlmsg_request);
+}
+
+struct iwpm_nlmsg_request *iwpm_find_nlmsg_request(__u32 echo_seq)
+{
+	struct iwpm_nlmsg_request *nlmsg_request;
+	struct iwpm_nlmsg_request *found_request = NULL;
+	unsigned long flags;
+
+	spin_lock_irqsave(&iwpm_nlmsg_req_lock, flags);
+	list_for_each_entry(nlmsg_request, &iwpm_nlmsg_req_list,
+			    inprocess_list) {
+		if (nlmsg_request->nlmsg_seq == echo_seq) {
+			found_request = nlmsg_request;
+			kref_get(&nlmsg_request->kref);
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&iwpm_nlmsg_req_lock, flags);
+	return found_request;
+}
+
+int iwpm_wait_complete_req(struct iwpm_nlmsg_request *nlmsg_request)
+{
+	int ret;
+	init_waitqueue_head(&nlmsg_request->waitq);
+
+	ret = wait_event_timeout(nlmsg_request->waitq,
+			(nlmsg_request->request_done != 0), IWPM_NL_TIMEOUT);
+	if (!ret) {
+		ret = -EINVAL;
+		pr_info("%s: Timeout %d sec for netlink request (seq = %u)\n",
+			__func__, (IWPM_NL_TIMEOUT/HZ), nlmsg_request->nlmsg_seq);
+	} else {
+		ret = nlmsg_request->err_code;
+	}
+	kref_put(&nlmsg_request->kref, iwpm_free_nlmsg_request);
+	return ret;
+}
+
+int iwpm_get_nlmsg_seq(void)
+{
+	return atomic_inc_return(&iwpm_admin.nlmsg_seq);
+}
+
+int iwpm_valid_client(u8 nl_client)
+{
+	if (nl_client >= RDMA_NL_NUM_CLIENTS)
+		return 0;
+	return iwpm_admin.client_list[nl_client];
+}
+
+void iwpm_set_valid(u8 nl_client, int valid)
+{
+	if (nl_client >= RDMA_NL_NUM_CLIENTS)
+		return;
+	iwpm_admin.client_list[nl_client] = valid;
+}
+
+/* valid client */
+int iwpm_registered_client(u8 nl_client)
+{
+	return iwpm_admin.reg_list[nl_client];
+}
+
+/* valid client */
+void iwpm_set_registered(u8 nl_client, int reg)
+{
+	iwpm_admin.reg_list[nl_client] = reg;
+}
+
+int iwpm_compare_sockaddr(struct sockaddr_storage *a_sockaddr,
+				struct sockaddr_storage *b_sockaddr)
+{
+	if (a_sockaddr->ss_family != b_sockaddr->ss_family)
+		return 1;
+	if (a_sockaddr->ss_family == AF_INET) {
+		struct sockaddr_in *a4_sockaddr =
+			(struct sockaddr_in *)a_sockaddr;
+		struct sockaddr_in *b4_sockaddr =
+			(struct sockaddr_in *)b_sockaddr;
+		if (!memcmp(&a4_sockaddr->sin_addr,
+			&b4_sockaddr->sin_addr, sizeof(struct in_addr))
+			&& a4_sockaddr->sin_port == b4_sockaddr->sin_port)
+				return 0;
+
+	} else if (a_sockaddr->ss_family == AF_INET6) {
+		struct sockaddr_in6 *a6_sockaddr =
+			(struct sockaddr_in6 *)a_sockaddr;
+		struct sockaddr_in6 *b6_sockaddr =
+			(struct sockaddr_in6 *)b_sockaddr;
+		if (!memcmp(&a6_sockaddr->sin6_addr,
+			&b6_sockaddr->sin6_addr, sizeof(struct in6_addr))
+			&& a6_sockaddr->sin6_port == b6_sockaddr->sin6_port)
+				return 0;
+
+	} else {
+		pr_err("%s: Invalid sockaddr family\n", __func__);
+	}
+	return 1;
+}
+
+struct sk_buff *iwpm_create_nlmsg(u32 nl_op, struct nlmsghdr **nlh,
+						int nl_client)
+{
+	struct sk_buff *skb = NULL;
+
+	skb = dev_alloc_skb(NLMSG_GOODSIZE);
+	if (!skb) {
+		pr_err("%s Unable to allocate skb\n", __func__);
+		goto create_nlmsg_exit;
+	}
+	if (!(ibnl_put_msg(skb, nlh, 0, 0, nl_client, nl_op,
+			   NLM_F_REQUEST))) {
+		pr_warn("%s: Unable to put the nlmsg header\n", __func__);
+		dev_kfree_skb(skb);
+		skb = NULL;
+	}
+create_nlmsg_exit:
+	return skb;
+}
+
+int iwpm_parse_nlmsg(struct netlink_callback *cb, int policy_max,
+				   const struct nla_policy *nlmsg_policy,
+				   struct nlattr *nltb[], const char *msg_type)
+{
+	int nlh_len = 0;
+	int ret;
+	const char *err_str = "";
+
+	ret = nlmsg_validate(cb->nlh, nlh_len, policy_max-1, nlmsg_policy);
+	if (ret) {
+		err_str = "Invalid attribute";
+		goto parse_nlmsg_error;
+	}
+	ret = nlmsg_parse(cb->nlh, nlh_len, nltb, policy_max-1, nlmsg_policy);
+	if (ret) {
+		err_str = "Unable to parse the nlmsg";
+		goto parse_nlmsg_error;
+	}
+	ret = iwpm_validate_nlmsg_attr(nltb, policy_max);
+	if (ret) {
+		err_str = "Invalid NULL attribute";
+		goto parse_nlmsg_error;
+	}
+	return 0;
+parse_nlmsg_error:
+	pr_warn("%s: %s (msg type %s ret = %d)\n",
+			__func__, err_str, msg_type, ret);
+	return ret;
+}
+
+void iwpm_print_sockaddr(struct sockaddr_storage *sockaddr, char *msg)
+{
+	struct sockaddr_in6 *sockaddr_v6;
+	struct sockaddr_in *sockaddr_v4;
+
+	switch (sockaddr->ss_family) {
+	case AF_INET:
+		sockaddr_v4 = (struct sockaddr_in *)sockaddr;
+		pr_debug("%s IPV4 %pI4: %u(0x%04X)\n",
+			msg, &sockaddr_v4->sin_addr,
+			ntohs(sockaddr_v4->sin_port),
+			ntohs(sockaddr_v4->sin_port));
+		break;
+	case AF_INET6:
+		sockaddr_v6 = (struct sockaddr_in6 *)sockaddr;
+		pr_debug("%s IPV6 %pI6: %u(0x%04X)\n",
+			msg, &sockaddr_v6->sin6_addr,
+			ntohs(sockaddr_v6->sin6_port),
+			ntohs(sockaddr_v6->sin6_port));
+		break;
+	default:
+		break;
+	}
+}
+
+static u32 iwpm_ipv6_jhash(struct sockaddr_in6 *ipv6_sockaddr)
+{
+	u32 ipv6_hash = jhash(&ipv6_sockaddr->sin6_addr, sizeof(struct in6_addr), 0);
+	u32 hash = jhash_2words(ipv6_hash, (__force u32) ipv6_sockaddr->sin6_port, 0);
+	return hash;
+}
+
+static u32 iwpm_ipv4_jhash(struct sockaddr_in *ipv4_sockaddr)
+{
+	u32 ipv4_hash = jhash(&ipv4_sockaddr->sin_addr, sizeof(struct in_addr), 0);
+	u32 hash = jhash_2words(ipv4_hash, (__force u32) ipv4_sockaddr->sin_port, 0);
+	return hash;
+}
+
+static struct hlist_head *get_hash_bucket_head(struct sockaddr_storage
+					       *local_sockaddr,
+					       struct sockaddr_storage
+					       *mapped_sockaddr)
+{
+	u32 local_hash, mapped_hash, hash;
+
+	if (local_sockaddr->ss_family == AF_INET) {
+		local_hash = iwpm_ipv4_jhash((struct sockaddr_in *) local_sockaddr);
+		mapped_hash = iwpm_ipv4_jhash((struct sockaddr_in *) mapped_sockaddr);
+
+	} else if (local_sockaddr->ss_family == AF_INET6) {
+		local_hash = iwpm_ipv6_jhash((struct sockaddr_in6 *) local_sockaddr);
+		mapped_hash = iwpm_ipv6_jhash((struct sockaddr_in6 *) mapped_sockaddr);
+	} else {
+		pr_err("%s: Invalid sockaddr family\n", __func__);
+		return NULL;
+	}
+
+	if (local_hash == mapped_hash) /* if port mapper isn't available */
+		hash = local_hash;
+	else
+		hash = jhash_2words(local_hash, mapped_hash, 0);
+
+	return &iwpm_hash_bucket[hash & IWPM_HASH_BUCKET_MASK];
+}
+
+static int send_mapinfo_num(u32 mapping_num, u8 nl_client, int iwpm_pid)
+{
+	struct sk_buff *skb = NULL;
+	struct nlmsghdr *nlh;
+	u32 msg_seq;
+	const char *err_str = "";
+	int ret = -EINVAL;
+
+	skb = iwpm_create_nlmsg(RDMA_NL_IWPM_MAPINFO_NUM, &nlh, nl_client);
+	if (!skb) {
+		err_str = "Unable to create a nlmsg";
+		goto mapinfo_num_error;
+	}
+	nlh->nlmsg_seq = iwpm_get_nlmsg_seq();
+	msg_seq = 0;
+	err_str = "Unable to put attribute of mapinfo number nlmsg";
+	ret = ibnl_put_attr(skb, nlh, sizeof(u32), &msg_seq, IWPM_NLA_MAPINFO_SEQ);
+	if (ret)
+		goto mapinfo_num_error;
+	ret = ibnl_put_attr(skb, nlh, sizeof(u32),
+				&mapping_num, IWPM_NLA_MAPINFO_SEND_NUM);
+	if (ret)
+		goto mapinfo_num_error;
+	ret = ibnl_unicast(skb, nlh, iwpm_pid);
+	if (ret) {
+		skb = NULL;
+		err_str = "Unable to send a nlmsg";
+		goto mapinfo_num_error;
+	}
+	pr_debug("%s: Sent mapping number = %d\n", __func__, mapping_num);
+	return 0;
+mapinfo_num_error:
+	pr_info("%s: %s\n", __func__, err_str);
+	if (skb)
+		dev_kfree_skb(skb);
+	return ret;
+}
+
+static int send_nlmsg_done(struct sk_buff *skb, u8 nl_client, int iwpm_pid)
+{
+	struct nlmsghdr *nlh = NULL;
+	int ret = 0;
+
+	if (!skb)
+		return ret;
+	if (!(ibnl_put_msg(skb, &nlh, 0, 0, nl_client,
+			   RDMA_NL_IWPM_MAPINFO, NLM_F_MULTI))) {
+		pr_warn("%s Unable to put NLMSG_DONE\n", __func__);
+		return -ENOMEM;
+	}
+	nlh->nlmsg_type = NLMSG_DONE;
+	ret = ibnl_unicast(skb, (struct nlmsghdr *)skb->data, iwpm_pid);
+	if (ret)
+		pr_warn("%s Unable to send a nlmsg\n", __func__);
+	return ret;
+}
+
+int iwpm_send_mapinfo(u8 nl_client, int iwpm_pid)
+{
+	struct iwpm_mapping_info *map_info;
+	struct sk_buff *skb = NULL;
+	struct nlmsghdr *nlh;
+	int skb_num = 0, mapping_num = 0;
+	int i = 0, nlmsg_bytes = 0;
+	unsigned long flags;
+	const char *err_str = "";
+	int ret;
+
+	skb = dev_alloc_skb(NLMSG_GOODSIZE);
+	if (!skb) {
+		ret = -ENOMEM;
+		err_str = "Unable to allocate skb";
+		goto send_mapping_info_exit;
+	}
+	skb_num++;
+	spin_lock_irqsave(&iwpm_mapinfo_lock, flags);
+	for (i = 0; i < IWPM_HASH_BUCKET_SIZE; i++) {
+		hlist_for_each_entry(map_info, &iwpm_hash_bucket[i],
+				     hlist_node) {
+			if (map_info->nl_client != nl_client)
+				continue;
+			nlh = NULL;
+			if (!(ibnl_put_msg(skb, &nlh, 0, 0, nl_client,
+					RDMA_NL_IWPM_MAPINFO, NLM_F_MULTI))) {
+				ret = -ENOMEM;
+				err_str = "Unable to put the nlmsg header";
+				goto send_mapping_info_unlock;
+			}
+			err_str = "Unable to put attribute of the nlmsg";
+			ret = ibnl_put_attr(skb, nlh,
+					sizeof(struct sockaddr_storage),
+					&map_info->local_sockaddr,
+					IWPM_NLA_MAPINFO_LOCAL_ADDR);
+			if (ret)
+				goto send_mapping_info_unlock;
+
+			ret = ibnl_put_attr(skb, nlh,
+					sizeof(struct sockaddr_storage),
+					&map_info->mapped_sockaddr,
+					IWPM_NLA_MAPINFO_MAPPED_ADDR);
+			if (ret)
+				goto send_mapping_info_unlock;
+
+			iwpm_print_sockaddr(&map_info->local_sockaddr,
+				"send_mapping_info: Local sockaddr:");
+			iwpm_print_sockaddr(&map_info->mapped_sockaddr,
+				"send_mapping_info: Mapped local sockaddr:");
+			mapping_num++;
+			nlmsg_bytes += nlh->nlmsg_len;
+
+			/* check if all mappings can fit in one skb */
+			if (NLMSG_GOODSIZE - nlmsg_bytes < nlh->nlmsg_len * 2) {
+				/* and leave room for NLMSG_DONE */
+				nlmsg_bytes = 0;
+				skb_num++;
+				spin_unlock_irqrestore(&iwpm_mapinfo_lock,
+						       flags);
+				/* send the skb */
+				ret = send_nlmsg_done(skb, nl_client, iwpm_pid);
+				skb = NULL;
+				if (ret) {
+					err_str = "Unable to send map info";
+					goto send_mapping_info_exit;
+				}
+				if (skb_num == IWPM_MAPINFO_SKB_COUNT) {
+					ret = -ENOMEM;
+					err_str = "Insufficient skbs for map info";
+					goto send_mapping_info_exit;
+				}
+				skb = dev_alloc_skb(NLMSG_GOODSIZE);
+				if (!skb) {
+					ret = -ENOMEM;
+					err_str = "Unable to allocate skb";
+					goto send_mapping_info_exit;
+				}
+				spin_lock_irqsave(&iwpm_mapinfo_lock, flags);
+			}
+		}
+	}
+send_mapping_info_unlock:
+	spin_unlock_irqrestore(&iwpm_mapinfo_lock, flags);
+send_mapping_info_exit:
+	if (ret) {
+		pr_warn("%s: %s (ret = %d)\n", __func__, err_str, ret);
+		if (skb)
+			dev_kfree_skb(skb);
+		return ret;
+	}
+	send_nlmsg_done(skb, nl_client, iwpm_pid);
+	return send_mapinfo_num(mapping_num, nl_client, iwpm_pid);
+}
+
+int iwpm_mapinfo_available(void)
+{
+	unsigned long flags;
+	int full_bucket = 0, i = 0;
+
+	spin_lock_irqsave(&iwpm_mapinfo_lock, flags);
+	if (iwpm_hash_bucket) {
+		for (i = 0; i < IWPM_HASH_BUCKET_SIZE; i++) {
+			if (!hlist_empty(&iwpm_hash_bucket[i])) {
+				full_bucket = 1;
+				break;
+			}
+		}
+	}
+	spin_unlock_irqrestore(&iwpm_mapinfo_lock, flags);
+	return full_bucket;
+}