cld80211-lib: Create cld80211 lib for communication with driver

Create netlink socket of type NETLINK_GENERIC and initialize with
netlink family cld80211.
Provide below APIs to the client,
1. Init and deinit of library
2. Subscribe/Unsubscribe for multicast groups
3. Send and recv of nlmsg to/from driver

Change-Id: I39bb5dac49dec5e0b011080ee3ffcb89d314c2b5

3 files changed, 683 insertions, 0 deletions

diff --git a/cld80211-lib/Android.mk b/cld80211-lib/Android.mk
new file mode 100644
index 0000000..d58edb8
--- /dev/null
+++ b/cld80211-lib/Android.mk
@@ -0,0 +1,27 @@
+LOCAL_PATH := $(call my-dir)
+
+include $(CLEAR_VARS)
+LOCAL_MODULE := libcld80211
+LOCAL_CLANG := true
+LOCAL_MODULE_TAGS := optional
+LOCAL_C_INCLUDES += $(LOCAL_PATH) \
+	external/libnl/include
+LOCAL_SHARED_LIBRARIES := libcutils libnl liblog
+LOCAL_SRC_FILES := cld80211_lib.c
+LOCAL_CFLAGS += -Wall -Werror -Wno-unused-parameter
+LOCAL_COPY_HEADERS_TO := cld80211-lib
+LOCAL_COPY_HEADERS := cld80211_lib.h
+include $(BUILD_SHARED_LIBRARY)
+
+include $(CLEAR_VARS)
+LOCAL_MODULE := libcld80211
+LOCAL_CLANG := true
+LOCAL_MODULE_TAGS := optional
+LOCAL_C_INCLUDES += $(LOCAL_PATH) \
+	external/libnl/include
+LOCAL_SHARED_LIBRARIES := libcutils libnl liblog
+LOCAL_SRC_FILES := cld80211_lib.c
+LOCAL_CFLAGS += -Wall -Werror -Wno-unused-parameter
+LOCAL_COPY_HEADERS_TO := cld80211-lib
+LOCAL_COPY_HEADERS := cld80211_lib.h
+include $(BUILD_STATIC_LIBRARY)
diff --git a/cld80211-lib/cld80211_lib.c b/cld80211-lib/cld80211_lib.c
new file mode 100644
index 0000000..abec22c
--- /dev/null
+++ b/cld80211-lib/cld80211_lib.c
@@ -0,0 +1,510 @@
+/*
+ * Driver interaction with Linux nl80211/cfg80211
+ * Copyright (c) 2002-2015, Jouni Malinen <j@w1.fi>
+ * Copyright (c) 2003-2004, Instant802 Networks, Inc.
+ * Copyright (c) 2005-2006, Devicescape Software, Inc.
+ * Copyright (c) 2007, Johannes Berg <johannes@sipsolutions.net>
+ * Copyright (c) 2009-2010, Atheros Communications
+ * Copyright (c) 2017, The Linux Foundation. All rights reserved.
+ *
+ * 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
+ *     * 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.
+ *     * Neither the name of The Linux Foundation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
+ * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE
+ *
+ */
+
+#include <errno.h>
+#include <netlink/genl/family.h>
+#include <netlink/genl/ctrl.h>
+#include <linux/pkt_sched.h>
+#include <unistd.h>
+#include <utils/Log.h>
+#include "cld80211_lib.h"
+
+#undef LOG_TAG
+#define LOG_TAG "CLD80211"
+#define SOCK_BUF_SIZE (256*1024)
+
+struct family_data {
+	const char *group;
+	int id;
+};
+
+
+static struct nl_sock * create_nl_socket(int protocol)
+{
+	struct nl_sock *sock;
+
+	sock = nl_socket_alloc();
+	if (sock == NULL) {
+		ALOGE("%s: Failed to create NL socket, err: %d",
+		      getprogname(), errno);
+		return NULL;
+	}
+
+	if (nl_connect(sock, protocol)) {
+		ALOGE("%s: Could not connect sock, err: %d",
+		      getprogname(), errno);
+		nl_socket_free(sock);
+		return NULL;
+	}
+
+	return sock;
+}
+
+
+static int init_exit_sockets(struct cld80211_ctx *ctx)
+{
+	ctx->exit_sockets[0] = -1;
+	ctx->exit_sockets[1] = -1;
+	if (socketpair(AF_UNIX, SOCK_STREAM, 0, &ctx->exit_sockets[0]) == -1) {
+		ALOGE("%s: Failed to create exit socket pair", getprogname());
+		return -1;
+	}
+	ALOGI("%s: initialized exit socket pair", getprogname());
+
+	return 0;
+}
+
+
+static void cleanup_exit_sockets(struct cld80211_ctx *ctx)
+{
+	if (ctx->exit_sockets[0] >= 0) {
+		close(ctx->exit_sockets[0]);
+		ctx->exit_sockets[0] = -1;
+	}
+
+	if (ctx->exit_sockets[1] >= 0) {
+		close(ctx->exit_sockets[1]);
+		ctx->exit_sockets[1] = -1;
+	}
+}
+
+
+void exit_cld80211_recv(struct cld80211_ctx *ctx)
+{
+	if (!ctx) {
+		ALOGE("%s: ctx is NULL: %s", getprogname(), __func__);
+		return;
+	}
+	TEMP_FAILURE_RETRY(write(ctx->exit_sockets[0], "E", 1));
+	ALOGI("%s: Sent msg on exit sock to unblock poll()", getprogname());
+}
+
+
+/* Event handlers */
+static int response_handler(struct nl_msg *msg, void *arg)
+{
+	UNUSED(msg);
+	UNUSED(arg);
+	ALOGI("%s: Received nlmsg response: no callback registered;drop it",
+	      getprogname());
+
+	return NL_SKIP;
+}
+
+
+static int ack_handler(struct nl_msg *msg, void *arg)
+{
+	int *err = (int *)arg;
+	*err = 0;
+	UNUSED(msg);
+	return NL_STOP;
+}
+
+
+static int finish_handler(struct nl_msg *msg, void *arg)
+{
+	int *ret = (int *)arg;
+	*ret = 0;
+	UNUSED(msg);
+	return NL_SKIP;
+}
+
+
+static int error_handler(struct sockaddr_nl *nla, struct nlmsgerr *err,
+			 void *arg)
+{
+	int *ret = (int *)arg;
+	*ret = err->error;
+
+	UNUSED(nla);
+	ALOGE("%s: error_handler received : %d", getprogname(), err->error);
+	return NL_SKIP;
+}
+
+
+static int no_seq_check(struct nl_msg *msg, void *arg)
+{
+	UNUSED(msg);
+	UNUSED(arg);
+	return NL_OK;
+}
+
+
+int cld80211_recv_msg(struct nl_sock *sock, struct nl_cb *cb)
+{
+	if (!sock || !cb) {
+		ALOGE("%s: %s is NULL", getprogname(), sock?"cb":"sock");
+		return -EINVAL;
+	}
+
+	int res = nl_recvmsgs(sock, cb);
+	if(res)
+		ALOGE("%s: Error :%d while reading nl msg , err: %d",
+		      getprogname(), res, errno);
+	return res;
+}
+
+
+static void cld80211_handle_event(int events, struct nl_sock *sock,
+				  struct nl_cb *cb)
+{
+	if (events & POLLERR) {
+		ALOGE("%s: Error reading from socket", getprogname());
+		cld80211_recv_msg(sock, cb);
+	} else if (events & POLLHUP) {
+		ALOGE("%s: Remote side hung up", getprogname());
+	} else if (events & POLLIN) {
+		cld80211_recv_msg(sock, cb);
+	} else {
+		ALOGE("%s: Unknown event - %0x", getprogname(), events);
+	}
+}
+
+
+static int family_handler(struct nl_msg *msg, void *arg)
+{
+	struct family_data *res = arg;
+	struct nlattr *tb[CTRL_ATTR_MAX + 1];
+	struct genlmsghdr *gnlh = nlmsg_data(nlmsg_hdr(msg));
+	struct nlattr *mcgrp;
+	int i;
+
+	nla_parse(tb, CTRL_ATTR_MAX, genlmsg_attrdata(gnlh, 0),
+			genlmsg_attrlen(gnlh, 0), NULL);
+	if (!tb[CTRL_ATTR_MCAST_GROUPS])
+		return NL_SKIP;
+
+	nla_for_each_nested(mcgrp, tb[CTRL_ATTR_MCAST_GROUPS], i) {
+		struct nlattr *tb2[CTRL_ATTR_MCAST_GRP_MAX + 1];
+		nla_parse(tb2, CTRL_ATTR_MCAST_GRP_MAX, nla_data(mcgrp),
+				nla_len(mcgrp), NULL);
+
+		if (!tb2[CTRL_ATTR_MCAST_GRP_NAME] ||
+			!tb2[CTRL_ATTR_MCAST_GRP_ID] ||
+			strncmp(nla_data(tb2[CTRL_ATTR_MCAST_GRP_NAME]),
+				   res->group,
+				   nla_len(tb2[CTRL_ATTR_MCAST_GRP_NAME])) != 0)
+			continue;
+		res->id = nla_get_u32(tb2[CTRL_ATTR_MCAST_GRP_ID]);
+		break;
+	};
+
+	return NL_SKIP;
+}
+
+
+static int get_multicast_id(struct cld80211_ctx *ctx, const char *group)
+{
+	struct family_data res = { group, -ENOENT };
+	struct nl_msg *nlmsg = nlmsg_alloc();
+
+	if (!nlmsg) {
+		return -1;
+	}
+
+	genlmsg_put(nlmsg, 0, 0, ctx->nlctrl_familyid, 0, 0,
+	            CTRL_CMD_GETFAMILY, 0);
+	nla_put_string(nlmsg, CTRL_ATTR_FAMILY_NAME, "cld80211");
+
+	cld80211_send_recv_msg(ctx, nlmsg, family_handler, &res);
+	ALOGI("%s: nlctrl family id: %d group: %s mcast_id: %d", getprogname(),
+				   ctx->nlctrl_familyid, group, res.id);
+	nlmsg_free(nlmsg);
+	return res.id;
+}
+
+
+int cld80211_add_mcast_group(struct cld80211_ctx *ctx, const char* mcgroup)
+{
+	if (!ctx || !mcgroup) {
+		ALOGE("%s: ctx/mcgroup is NULL: %s", getprogname(), __func__);
+		return 0;
+	}
+	int id = get_multicast_id(ctx, mcgroup);
+	if (id < 0) {
+		ALOGE("%s: Could not find group %s, errno: %d id: %d",
+		      getprogname(), mcgroup, errno, id);
+		return id;
+	}
+
+	int ret = nl_socket_add_membership(ctx->sock, id);
+	if (ret < 0) {
+		ALOGE("%s: Could not add membership to group %s, errno: %d",
+		      getprogname(), mcgroup, errno);
+	}
+
+	return ret;
+}
+
+
+int cld80211_remove_mcast_group(struct cld80211_ctx *ctx, const char* mcgroup)
+{
+	if (!ctx || !mcgroup) {
+		ALOGE("%s: ctx/mcgroup is NULL: %s", getprogname(), __func__);
+		return 0;
+	}
+	int id = get_multicast_id(ctx, mcgroup);
+	if (id < 0) {
+		ALOGE("%s: Could not find group %s, errno: %d id: %d",
+		      getprogname(), mcgroup, errno, id);
+		return id;
+	}
+
+	int ret = nl_socket_drop_membership(ctx->sock, id);
+	if (ret < 0) {
+		ALOGE("%s: Could not drop membership from group %s, errno: %d,"
+		      " ret: %d", getprogname(), mcgroup, errno, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+
+struct nl_msg *cld80211_msg_alloc(struct cld80211_ctx *ctx, int cmd,
+				  struct nlattr **nla_data, int pid)
+{
+	struct nl_msg *nlmsg;
+
+	if (!ctx || !nla_data) {
+		ALOGE("%s: ctx is null: %s", getprogname(), __func__);
+		return NULL;
+	}
+
+	nlmsg = nlmsg_alloc();
+	if (nlmsg == NULL) {
+		ALOGE("%s: Out of memory", getprogname());
+		return NULL;
+	}
+
+	genlmsg_put(nlmsg, pid, /* seq = */ 0, ctx->netlink_familyid,
+			0, 0, cmd, /* version = */ 0);
+
+	*nla_data = nla_nest_start(nlmsg, CLD80211_ATTR_VENDOR_DATA);
+	if (!nla_data)
+		goto cleanup;
+
+	return nlmsg;
+
+cleanup:
+	if (nlmsg)
+		nlmsg_free(nlmsg);
+	return NULL;
+}
+
+
+int cld80211_send_msg(struct cld80211_ctx *ctx, struct nl_msg *nlmsg)
+{
+	int err;
+
+	if (!ctx || !ctx->sock || !nlmsg) {
+		ALOGE("%s: Invalid data from client", getprogname());
+		return -EINVAL;
+	}
+
+	err = nl_send_auto_complete(ctx->sock, nlmsg);  /* send message */
+	if (err < 0) {
+		ALOGE("%s: failed to send msg: %d", getprogname(), err);
+		return err;
+	}
+
+	return 0;
+}
+
+
+int cld80211_send_recv_msg(struct cld80211_ctx *ctx, struct nl_msg *nlmsg,
+			   int (*valid_handler)(struct nl_msg *, void *),
+			   void *valid_data)
+{
+	int err;
+
+	if (!ctx || !ctx->sock || !nlmsg) {
+		ALOGE("%s: Invalid data from client", getprogname());
+		return -EINVAL;
+	}
+
+	struct nl_cb *cb = nl_cb_alloc(NL_CB_DEFAULT);
+	if (!cb)
+		return -ENOMEM;
+
+	err = nl_send_auto_complete(ctx->sock, nlmsg);  /* send message */
+	if (err < 0)
+		goto out;
+
+	err = 1;
+
+	nl_cb_set(cb, NL_CB_SEQ_CHECK, NL_CB_CUSTOM, no_seq_check, NULL);
+	nl_cb_err(cb, NL_CB_CUSTOM, error_handler, &err);
+	nl_cb_set(cb, NL_CB_FINISH, NL_CB_CUSTOM, finish_handler, &err);
+	nl_cb_set(cb, NL_CB_ACK, NL_CB_CUSTOM, ack_handler, &err);
+
+	if (valid_handler)
+		nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM,
+			  valid_handler, valid_data);
+	else
+		nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM,
+			  response_handler, valid_data);
+
+	while (err > 0) {    /* wait for reply */
+		int res = nl_recvmsgs(ctx->sock, cb);
+		if (res) {
+			ALOGE("%s: cld80211: nl_recvmsgs failed: %d",
+			      getprogname(), res);
+		}
+	}
+out:
+	nl_cb_put(cb);
+	return err;
+}
+
+
+int cld80211_recv(struct cld80211_ctx *ctx, int timeout, bool recv_multi_msg,
+		  int (*valid_handler)(struct nl_msg *, void *),
+		  void *cbctx)
+{
+	struct pollfd pfd[2];
+	struct nl_cb *cb;
+	int err;
+
+	if (!ctx || !ctx->sock || !valid_handler) {
+		ALOGE("%s: Invalid data from client", getprogname());
+		return -EINVAL;
+	}
+
+	cb = nl_cb_alloc(NL_CB_DEFAULT);
+	if (!cb)
+		return -ENOMEM;
+
+	memset(&pfd[0], 0, 2*sizeof(struct pollfd));
+
+	err = 1;
+
+	nl_cb_err(cb, NL_CB_CUSTOM, error_handler, &err);
+	nl_cb_set(cb, NL_CB_FINISH, NL_CB_CUSTOM, finish_handler, &err);
+	nl_cb_set(cb, NL_CB_ACK, NL_CB_CUSTOM, ack_handler, &err);
+	nl_cb_set(cb, NL_CB_SEQ_CHECK, NL_CB_CUSTOM, no_seq_check, NULL);
+	nl_cb_set(cb, NL_CB_VALID, NL_CB_CUSTOM, valid_handler, cbctx);
+
+	pfd[0].fd = nl_socket_get_fd(ctx->sock);
+	pfd[0].events = POLLIN;
+
+	pfd[1].fd = ctx->exit_sockets[1];
+	pfd[1].events = POLLIN;
+
+	do {
+		pfd[0].revents = 0;
+		pfd[1].revents = 0;
+		int result = poll(pfd, 2, timeout);
+		if (result < 0) {
+			ALOGE("%s: Error polling socket", getprogname());
+		} else if (pfd[0].revents & (POLLIN | POLLHUP | POLLERR)) {
+			cld80211_handle_event(pfd[0].revents, ctx->sock, cb);
+			if (!recv_multi_msg)
+				break;
+		} else {
+			ALOGI("%s: Exiting poll", getprogname());
+			break;
+		}
+	} while (1);
+
+	nl_cb_put(cb);
+	return 0;
+}
+
+
+struct cld80211_ctx * cld80211_init()
+{
+	struct cld80211_ctx *ctx;
+
+	ctx = (struct cld80211_ctx *)malloc(sizeof(struct cld80211_ctx));
+	if (ctx == NULL) {
+		ALOGE("%s: Failed to alloc cld80211_ctx", getprogname());
+		return NULL;
+	}
+	memset(ctx, 0, sizeof(struct cld80211_ctx));
+
+	ctx->sock = create_nl_socket(NETLINK_GENERIC);
+	if (ctx->sock == NULL) {
+		ALOGE("%s: Failed to create socket port", getprogname());
+		goto cleanup;
+	}
+
+	/* Set the socket buffer size */
+	if (nl_socket_set_buffer_size(ctx->sock, SOCK_BUF_SIZE , 0) < 0) {
+		ALOGE("%s: Could not set nl_socket RX buffer size for sock: %s",
+		      getprogname(), strerror(errno));
+		/* continue anyway with the default (smaller) buffer */
+	}
+
+	ctx->netlink_familyid = genl_ctrl_resolve(ctx->sock, "cld80211");
+	if (ctx->netlink_familyid < 0) {
+		ALOGE("%s: Could not resolve cld80211 familty id",
+		      getprogname());
+		goto cleanup;
+	}
+
+	ctx->nlctrl_familyid = genl_ctrl_resolve(ctx->sock, "nlctrl");
+	if (ctx->nlctrl_familyid < 0) {
+		ALOGE("%s: net link family nlctrl is not present: %d err:%d",
+			getprogname(), ctx->nlctrl_familyid, errno);
+		goto cleanup;
+	}
+
+
+	if (init_exit_sockets(ctx) != 0) {
+		ALOGE("%s: Failed to initialize exit sockets", getprogname());
+		goto cleanup;
+	}
+
+	return ctx;
+cleanup:
+	if (ctx->sock) {
+		nl_socket_free(ctx->sock);
+	}
+	free (ctx);
+	return NULL;
+}
+
+
+void cld80211_deinit(struct cld80211_ctx *ctx)
+{
+	if (!ctx || !ctx->sock) {
+		ALOGE("%s: ctx/sock is NULL", getprogname());
+		return;
+	}
+	nl_socket_free(ctx->sock);
+	cleanup_exit_sockets(ctx);
+	free (ctx);
+}
diff --git a/cld80211-lib/cld80211_lib.h b/cld80211-lib/cld80211_lib.h
new file mode 100644
index 0000000..16b3f20
--- /dev/null
+++ b/cld80211-lib/cld80211_lib.h
@@ -0,0 +1,146 @@
+/* Copyright (c) 2017, The Linux Foundation. All rights reserved.
+ *
+ * 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.
+ *     * Neither the name of The Linux Foundation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
+ * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+ * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
+ * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
+ * OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
+ * IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#ifndef CLD80211_LIB_H
+#define CLD80211_LIB_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+#include <netlink/genl/genl.h>
+#include <stdbool.h>
+
+#ifndef UNUSED
+#define UNUSED(x)    (void)(x)
+#endif
+
+struct cld80211_ctx {
+	struct nl_sock *sock;
+	int netlink_familyid;
+	/* socket pair used to exit from blocking poll*/
+	int exit_sockets[2];
+	int sock_buf_size;
+	int nlctrl_familyid;
+};
+
+/**
+ * enum cld80211_attr - Driver/Application embeds the data in nlmsg with the
+ *                      help of below attributes
+ * CLD80211_ATTR_VENDOR_DATA: Embed all other attributes in this nested
+ *                            attribute.
+ * CLD80211_ATTR_DATA: Embed driver/application data in this attribute
+ * Any new message in future can be added as another attribute
+ */
+enum cld80211_attr {
+	CLD80211_ATTR_VENDOR_DATA = 1,
+	CLD80211_ATTR_DATA,
+
+	__CLD80211_ATTR_AFTER_LAST,
+	CLD80211_ATTR_MAX = __CLD80211_ATTR_AFTER_LAST - 1
+};
+
+/**
+ * Create socket of type NETLINK_GENERIC
+ * Retuns valid sock only if socket creation is succesful and cld80211
+ * family is present, returns NULL otherwise
+ */
+struct cld80211_ctx *cld80211_init();
+
+/**
+ * free the socket created in cld80211_init()
+ */
+void cld80211_deinit(struct cld80211_ctx *ctx);
+
+/**
+ * Allocate nl_msg and populate family and genl header details
+ */
+struct nl_msg *cld80211_msg_alloc(struct cld80211_ctx *ctx, int cmd,
+				  struct nlattr **nla_data, int pid);
+
+/**
+ * Send nlmsg to driver and return; It doesn't wait for response
+ */
+int cld80211_send_msg(struct cld80211_ctx *ctx, struct nl_msg *nlmsg);
+
+/**
+ * Send nlmsg to driver and get response, if any
+ */
+int cld80211_send_recv_msg(struct cld80211_ctx *ctx, struct nl_msg *nlmsg,
+		      int (*valid_handler)(struct nl_msg *, void *),
+		      void *valid_data);
+
+/**
+ * Add membership for multicast group "mcgroup" to receive the messages
+ * sent to this group from driver
+ */
+int cld80211_add_mcast_group(struct cld80211_ctx *ctx, const char* mcgroup);
+
+/**
+ * Remove membership of multicast group "mcgroup" to stop receiving messages
+ * sent to this group from driver
+ */
+int cld80211_remove_mcast_group(struct cld80211_ctx *ctx, const char* mcgroup);
+
+/**
+ * Receive messages from driver on cld80211 family. Client can do
+ * a select()/poll() on the socket before calling this API.
+ * sock: nl_sock created for communication
+ * cb: nl callback context provided by client
+ * Returns corresponding errno when a failure happens while receiving nl msg
+ */
+int cld80211_recv_msg(struct nl_sock *sock, struct nl_cb *cb);
+
+/**
+ * Receive messages from driver on cld80211 family from the
+ * multicast groups subscribed
+ * timeout: Timeout in milliseconds for poll(); -1 is for infinite timeout.
+ * recv_multi_msg: Boolean flag to be sent false/true from client to indicate
+ *                 whether it wants to receive only one message or multiple
+ *                 messages from timeoutblock.
+ *                 false: Receive only one message and return
+ *                 true: Continue in the loop to receive multiple message till
+ *                       client explicitly sends exit via exit_cld80211_recv().
+ * cbctx: Context provided by client, which is to be used when an
+ *        nlmsg is received
+ * Returns corresponding errno when a failure happens while receiving nl msg
+ */
+int cld80211_recv(struct cld80211_ctx *ctx, int timeout, bool recv_multi_msg,
+		  int (*valid_handler)(struct nl_msg *, void *),
+		  void *cbctx);
+
+/**
+ * poll() is a blocking call on sock. Client has to unblock the poll()
+ * first to exit gracefully.
+ */
+void exit_cld80211_recv(struct cld80211_ctx *ctx);
+#ifdef __cplusplus
+}
+#endif
+
+#endif