/*
 * 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_MAPINFO_HASH_SIZE  512
#define IWPM_MAPINFO_HASH_MASK  (IWPM_MAPINFO_HASH_SIZE - 1)
#define IWPM_REMINFO_HASH_SIZE  64
#define IWPM_REMINFO_HASH_MASK  (IWPM_REMINFO_HASH_SIZE - 1)
#define IWPM_MSG_SIZE           512

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 struct hlist_head *iwpm_reminfo_bucket;
static DEFINE_SPINLOCK(iwpm_reminfo_lock);

static DEFINE_MUTEX(iwpm_admin_lock);
static struct iwpm_admin_data iwpm_admin;

/**
 * iwpm_init - Allocate resources for the iwarp port mapper
 * @nl_client: The index of the netlink client
 *
 * Should be called when network interface goes up.
 */
int iwpm_init(u8 nl_client)
{
        int ret = 0;
        mutex_lock(&iwpm_admin_lock);
        if (!refcount_read(&iwpm_admin.refcount)) {
                iwpm_hash_bucket = kcalloc(IWPM_MAPINFO_HASH_SIZE,
                                           sizeof(struct hlist_head),
                                           GFP_KERNEL);
                if (!iwpm_hash_bucket) {
                        ret = -ENOMEM;
                        goto init_exit;
                }
                iwpm_reminfo_bucket = kcalloc(IWPM_REMINFO_HASH_SIZE,
                                              sizeof(struct hlist_head),
                                              GFP_KERNEL);
                if (!iwpm_reminfo_bucket) {
                        kfree(iwpm_hash_bucket);
                        ret = -ENOMEM;
                        goto init_exit;
                }

                refcount_set(&iwpm_admin.refcount, 1);
        } else {
                refcount_inc(&iwpm_admin.refcount);
        }

init_exit:
        mutex_unlock(&iwpm_admin_lock);
        if (!ret) {
                iwpm_set_valid(nl_client, 1);
                iwpm_set_registration(nl_client, IWPM_REG_UNDEF);
                pr_debug("%s: Mapinfo and reminfo tables are created\n",
                                __func__);
        }
        return ret;
}

static void free_hash_bucket(void);
static void free_reminfo_bucket(void);

/**
 * iwpm_exit - Deallocate resources for the iwarp port mapper
 * @nl_client: The index of the netlink client
 *
 * Should be called when network interface goes down.
 */
int iwpm_exit(u8 nl_client)
{

        if (!iwpm_valid_client(nl_client))
                return -EINVAL;
        mutex_lock(&iwpm_admin_lock);
        if (!refcount_read(&iwpm_admin.refcount)) {
                mutex_unlock(&iwpm_admin_lock);
                pr_err("%s Incorrect usage - negative refcount\n", __func__);
                return -EINVAL;
        }
        if (refcount_dec_and_test(&iwpm_admin.refcount)) {
                free_hash_bucket();
                free_reminfo_bucket();
                pr_debug("%s: Resources are destroyed\n", __func__);
        }
        mutex_unlock(&iwpm_admin_lock);
        iwpm_set_valid(nl_client, 0);
        iwpm_set_registration(nl_client, IWPM_REG_UNDEF);
        return 0;
}

static struct hlist_head *get_mapinfo_hash_bucket(struct sockaddr_storage *,
                                               struct sockaddr_storage *);

/**
 * iwpm_create_mapinfo - Store local and mapped IPv4/IPv6 address
 *                       info in a hash table
 * @local_sockaddr: Local ip/tcp address
 * @mapped_sockaddr: Mapped local ip/tcp address
 * @nl_client: The index of the netlink client
 * @map_flags: IWPM mapping flags
 */
int iwpm_create_mapinfo(struct sockaddr_storage *local_sockaddr,
                        struct sockaddr_storage *mapped_sockaddr,
                        u8 nl_client, u32 map_flags)
{
        struct hlist_head *hash_bucket_head = NULL;
        struct iwpm_mapping_info *map_info;
        unsigned long flags;
        int ret = -EINVAL;

        if (!iwpm_valid_client(nl_client))
                return ret;
        map_info = kzalloc(sizeof(struct iwpm_mapping_info), GFP_KERNEL);
        if (!map_info)
                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;
        map_info->map_flags = map_flags;

        spin_lock_irqsave(&iwpm_mapinfo_lock, flags);
        if (iwpm_hash_bucket) {
                hash_bucket_head = get_mapinfo_hash_bucket(
                                        &map_info->local_sockaddr,
                                        &map_info->mapped_sockaddr);
                if (hash_bucket_head) {
                        hlist_add_head(&map_info->hlist_node, hash_bucket_head);
                        ret = 0;
                }
        }
        spin_unlock_irqrestore(&iwpm_mapinfo_lock, flags);

        if (!hash_bucket_head)
                kfree(map_info);
        return ret;
}

/**
 * iwpm_remove_mapinfo - Remove local and mapped IPv4/IPv6 address
 *                       info from the hash table
 * @local_sockaddr: Local ip/tcp address
 * @mapped_local_addr: Mapped local ip/tcp address
 *
 * Returns err code if mapping info is not found in the hash table,
 * otherwise returns 0
 */
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_mapinfo_hash_bucket(
                                        local_sockaddr,
                                        mapped_local_addr);
                if (!hash_bucket_head)
                        goto remove_mapinfo_exit;

                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;
                        }
                }
        }
remove_mapinfo_exit:
        spin_unlock_irqrestore(&iwpm_mapinfo_lock, flags);
        return ret;
}

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_MAPINFO_HASH_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);
}

static void free_reminfo_bucket(void)
{
        struct hlist_node *tmp_hlist_node;
        struct iwpm_remote_info *rem_info;
        unsigned long flags;
        int i;

        /* remove all the remote info from the list */
        spin_lock_irqsave(&iwpm_reminfo_lock, flags);
        for (i = 0; i < IWPM_REMINFO_HASH_SIZE; i++) {
                hlist_for_each_entry_safe(rem_info, tmp_hlist_node,
                        &iwpm_reminfo_bucket[i], hlist_node) {

                                hlist_del_init(&rem_info->hlist_node);
                                kfree(rem_info);
                        }
        }
        /* free the hash list */
        kfree(iwpm_reminfo_bucket);
        iwpm_reminfo_bucket = NULL;
        spin_unlock_irqrestore(&iwpm_reminfo_lock, flags);
}

static struct hlist_head *get_reminfo_hash_bucket(struct sockaddr_storage *,
                                                struct sockaddr_storage *);

void iwpm_add_remote_info(struct iwpm_remote_info *rem_info)
{
        struct hlist_head *hash_bucket_head;
        unsigned long flags;

        spin_lock_irqsave(&iwpm_reminfo_lock, flags);
        if (iwpm_reminfo_bucket) {
                hash_bucket_head = get_reminfo_hash_bucket(
                                        &rem_info->mapped_loc_sockaddr,
                                        &rem_info->mapped_rem_sockaddr);
                if (hash_bucket_head)
                        hlist_add_head(&rem_info->hlist_node, hash_bucket_head);
        }
        spin_unlock_irqrestore(&iwpm_reminfo_lock, flags);
}

/**
 * iwpm_get_remote_info - Get the remote connecting peer address info
 *
 * @mapped_loc_addr: Mapped local address of the listening peer
 * @mapped_rem_addr: Mapped remote address of the connecting peer
 * @remote_addr: To store the remote address of the connecting peer
 * @nl_client: The index of the netlink client
 *
 * The remote address info is retrieved and provided to the client in
 * the remote_addr. After that it is removed from the hash table
 */
int iwpm_get_remote_info(struct sockaddr_storage *mapped_loc_addr,
                         struct sockaddr_storage *mapped_rem_addr,
                         struct sockaddr_storage *remote_addr,
                         u8 nl_client)
{
        struct hlist_node *tmp_hlist_node;
        struct hlist_head *hash_bucket_head;
        struct iwpm_remote_info *rem_info = NULL;
        unsigned long flags;
        int ret = -EINVAL;

        if (!iwpm_valid_client(nl_client)) {
                pr_info("%s: Invalid client = %u\n", __func__, nl_client);
                return ret;
        }
        spin_lock_irqsave(&iwpm_reminfo_lock, flags);
        if (iwpm_reminfo_bucket) {
                hash_bucket_head = get_reminfo_hash_bucket(
                                        mapped_loc_addr,
                                        mapped_rem_addr);
                if (!hash_bucket_head)
                        goto get_remote_info_exit;
                hlist_for_each_entry_safe(rem_info, tmp_hlist_node,
                                        hash_bucket_head, hlist_node) {

                        if (!iwpm_compare_sockaddr(&rem_info->mapped_loc_sockaddr,
                                mapped_loc_addr) &&
                                !iwpm_compare_sockaddr(&rem_info->mapped_rem_sockaddr,
                                mapped_rem_addr)) {

                                memcpy(remote_addr, &rem_info->remote_sockaddr,
                                        sizeof(struct sockaddr_storage));
                                iwpm_print_sockaddr(remote_addr,
                                                "get_remote_info: Remote sockaddr:");

                                hlist_del_init(&rem_info->hlist_node);
                                kfree(rem_info);
                                ret = 0;
                                break;
                        }
                }
        }
get_remote_info_exit:
        spin_unlock_irqrestore(&iwpm_reminfo_lock, flags);
        return ret;
}

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)
                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;
        sema_init(&nlmsg_request->sem, 1);
        down(&nlmsg_request->sem);
        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;

        ret = down_timeout(&nlmsg_request->sem, 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)
{
        return iwpm_admin.client_list[nl_client];
}

void iwpm_set_valid(u8 nl_client, int valid)
{
        iwpm_admin.client_list[nl_client] = valid;
}

/* valid client */
u32 iwpm_get_registration(u8 nl_client)
{
        return iwpm_admin.reg_list[nl_client];
}

/* valid client */
void iwpm_set_registration(u8 nl_client, u32 reg)
{
        iwpm_admin.reg_list[nl_client] = reg;
}

/* valid client */
u32 iwpm_check_registration(u8 nl_client, u32 reg)
{
        return (iwpm_get_registration(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(IWPM_MSG_SIZE);
        if (!skb)
                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_deprecated(cb->nlh, nlh_len, policy_max - 1,
                                        nlmsg_policy, NULL);
        if (ret) {
                err_str = "Invalid attribute";
                goto parse_nlmsg_error;
        }
        ret = nlmsg_parse_deprecated(cb->nlh, nlh_len, nltb, policy_max - 1,
                                     nlmsg_policy, NULL);
        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 int get_hash_bucket(struct sockaddr_storage *a_sockaddr,
                                struct sockaddr_storage *b_sockaddr, u32 *hash)
{
        u32 a_hash, b_hash;

        if (a_sockaddr->ss_family == AF_INET) {
                a_hash = iwpm_ipv4_jhash((struct sockaddr_in *) a_sockaddr);
                b_hash = iwpm_ipv4_jhash((struct sockaddr_in *) b_sockaddr);

        } else if (a_sockaddr->ss_family == AF_INET6) {
                a_hash = iwpm_ipv6_jhash((struct sockaddr_in6 *) a_sockaddr);
                b_hash = iwpm_ipv6_jhash((struct sockaddr_in6 *) b_sockaddr);
        } else {
                pr_err("%s: Invalid sockaddr family\n", __func__);
                return -EINVAL;
        }

        if (a_hash == b_hash) /* if port mapper isn't available */
                *hash = a_hash;
        else
                *hash = jhash_2words(a_hash, b_hash, 0);
        return 0;
}

static struct hlist_head *get_mapinfo_hash_bucket(struct sockaddr_storage
                                *local_sockaddr, struct sockaddr_storage
                                *mapped_sockaddr)
{
        u32 hash;
        int ret;

        ret = get_hash_bucket(local_sockaddr, mapped_sockaddr, &hash);
        if (ret)
                return NULL;
        return &iwpm_hash_bucket[hash & IWPM_MAPINFO_HASH_MASK];
}

static struct hlist_head *get_reminfo_hash_bucket(struct sockaddr_storage
                                *mapped_loc_sockaddr, struct sockaddr_storage
                                *mapped_rem_sockaddr)
{
        u32 hash;
        int ret;

        ret = get_hash_bucket(mapped_loc_sockaddr, mapped_rem_sockaddr, &hash);
        if (ret)
                return NULL;
        return &iwpm_reminfo_bucket[hash & IWPM_REMINFO_HASH_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;

        nlmsg_end(skb, nlh);

        ret = rdma_nl_unicast(&init_net, skb, iwpm_pid);
        if (ret) {
                skb = NULL;
                err_str = "Unable to send a nlmsg";
                goto mapinfo_num_error;
        }
        pr_debug("%s: Sent mapping number = %u\n", __func__, mapping_num);
        return 0;
mapinfo_num_error:
        pr_info("%s: %s\n", __func__, err_str);
        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__);
                dev_kfree_skb(skb);
                return -ENOMEM;
        }
        nlh->nlmsg_type = NLMSG_DONE;
        ret = rdma_nl_unicast(&init_net, skb, 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);
        ret = -EINVAL;
        for (i = 0; i < IWPM_MAPINFO_HASH_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;

                        if (iwpm_ulib_version > IWPM_UABI_VERSION_MIN) {
                                ret = ibnl_put_attr(skb, nlh, sizeof(u32),
                                                &map_info->map_flags,
                                                IWPM_NLA_MAPINFO_FLAGS);
                                if (ret)
                                        goto send_mapping_info_unlock;
                        }

                        nlmsg_end(skb, nlh);

                        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);
                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_MAPINFO_HASH_SIZE; i++) {
                        if (!hlist_empty(&iwpm_hash_bucket[i])) {
                                full_bucket = 1;
                                break;
                        }
                }
        }
        spin_unlock_irqrestore(&iwpm_mapinfo_lock, flags);
        return full_bucket;
}

int iwpm_send_hello(u8 nl_client, int iwpm_pid, u16 abi_version)
{
        struct sk_buff *skb = NULL;
        struct nlmsghdr *nlh;
        const char *err_str = "";
        int ret = -EINVAL;

        skb = iwpm_create_nlmsg(RDMA_NL_IWPM_HELLO, &nlh, nl_client);
        if (!skb) {
                err_str = "Unable to create a nlmsg";
                goto hello_num_error;
        }
        nlh->nlmsg_seq = iwpm_get_nlmsg_seq();
        err_str = "Unable to put attribute of abi_version into nlmsg";
        ret = ibnl_put_attr(skb, nlh, sizeof(u16), &abi_version,
                            IWPM_NLA_HELLO_ABI_VERSION);
        if (ret)
                goto hello_num_error;
        nlmsg_end(skb, nlh);

        ret = rdma_nl_unicast(&init_net, skb, iwpm_pid);
        if (ret) {
                skb = NULL;
                err_str = "Unable to send a nlmsg";
                goto hello_num_error;
        }
        pr_debug("%s: Sent hello abi_version = %u\n", __func__, abi_version);
        return 0;
hello_num_error:
        pr_info("%s: %s\n", __func__, err_str);
        dev_kfree_skb(skb);
        return ret;
}