[PATCH 1/2] net: qrtr: Migrate nameservice to kernel from userspace

[Manivannan Sadhasivam]

The QRTR nameservice has been maintained in userspace for some time. This
commit migrates it to Linux kernel. This change is required in order to
eliminate the need of starting a userspace daemon for making the WiFi
functional for ath11k based devices.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
---
 net/qrtr/Makefile |   2 +-
 net/qrtr/ns.c     | 730 ++++++++++++++++++++++++++++++++++++++++++++++
 net/qrtr/qrtr.c   |  48 +--
 net/qrtr/qrtr.h   |   4 +
 4 files changed, 745 insertions(+), 39 deletions(-)
 create mode 100644 net/qrtr/ns.c

diff --git a/net/qrtr/Makefile b/net/qrtr/Makefile
index 1c6d6c120fb7..32d4e923925d 100644
--- a/net/qrtr/Makefile
+++ b/net/qrtr/Makefile
@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-only
-obj-$(CONFIG_QRTR) := qrtr.o
+obj-$(CONFIG_QRTR) := qrtr.o ns.o
 
 obj-$(CONFIG_QRTR_SMD) += qrtr-smd.o
 qrtr-smd-y	:= smd.o
diff --git a/net/qrtr/ns.c b/net/qrtr/ns.c
new file mode 100644
index 000000000000..7916b55364c1
--- /dev/null
+++ b/net/qrtr/ns.c
@@ -0,0 +1,730 @@
+// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
+/*
+ * Copyright (c) 2015, Sony Mobile Communications Inc.
+ * Copyright (c) 2013, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2020, Linaro Ltd.
+ */
+
+#include <linux/module.h>
+#include <linux/qrtr.h>
+#include <linux/workqueue.h>
+#include <net/sock.h>
+
+#include "qrtr.h"
+
+static RADIX_TREE(nodes, GFP_KERNEL);
+
+static struct {
+	struct socket *sock;
+	struct sockaddr_qrtr bcast_sq;
+	struct list_head lookups;
+	struct workqueue_struct *workqueue;
+	struct work_struct work;
+	int local_node;
+} qrtr_ns;
+
+static const char * const qrtr_ctrl_pkt_strings[] = {
+	[QRTR_TYPE_HELLO]	= "hello",
+	[QRTR_TYPE_BYE]		= "bye",
+	[QRTR_TYPE_NEW_SERVER]	= "new-server",
+	[QRTR_TYPE_DEL_SERVER]	= "del-server",
+	[QRTR_TYPE_DEL_CLIENT]	= "del-client",
+	[QRTR_TYPE_RESUME_TX]	= "resume-tx",
+	[QRTR_TYPE_EXIT]	= "exit",
+	[QRTR_TYPE_PING]	= "ping",
+	[QRTR_TYPE_NEW_LOOKUP]	= "new-lookup",
+	[QRTR_TYPE_DEL_LOOKUP]	= "del-lookup",
+};
+
+struct qrtr_server_filter {
+	unsigned int service;
+	unsigned int instance;
+	unsigned int ifilter;
+};
+
+struct qrtr_lookup {
+	unsigned int service;
+	unsigned int instance;
+
+	struct sockaddr_qrtr sq;
+	struct list_head li;
+};
+
+struct qrtr_server {
+	unsigned int service;
+	unsigned int instance;
+
+	unsigned int node;
+	unsigned int port;
+
+	struct list_head qli;
+};
+
+struct qrtr_node {
+	unsigned int id;
+	struct radix_tree_root servers;
+};
+
+static struct qrtr_node *node_get(unsigned int node_id)
+{
+	struct qrtr_node *node;
+
+	node = radix_tree_lookup(&nodes, node_id);
+	if (node)
+		return node;
+
+	/* If node didn't exist, allocate and insert it to the tree */
+	node = kzalloc(sizeof(*node), GFP_KERNEL);
+	if (!node)
+		return ERR_PTR(-ENOMEM);
+
+	node->id = node_id;
+
+	radix_tree_insert(&nodes, node_id, node);
+
+	return node;
+}
+
+static int server_match(const struct qrtr_server *srv,
+			const struct qrtr_server_filter *f)
+{
+	unsigned int ifilter = f->ifilter;
+
+	if (f->service != 0 && srv->service != f->service)
+		return 0;
+	if (!ifilter && f->instance)
+		ifilter = ~0;
+
+	return (srv->instance & ifilter) == f->instance;
+}
+
+static int service_announce_new(struct sockaddr_qrtr *dest,
+				struct qrtr_server *srv)
+{
+	struct qrtr_ctrl_pkt pkt;
+	struct msghdr msg = { };
+	struct kvec iv = { &pkt, sizeof(pkt) };
+
+	trace_printk("advertising new server [%d:%x]@[%d:%d]\n",
+		     srv->service, srv->instance, srv->node, srv->port);
+
+	memset(&pkt, 0, sizeof(pkt));
+	pkt.cmd = cpu_to_le32(QRTR_TYPE_NEW_SERVER);
+	pkt.server.service = cpu_to_le32(srv->service);
+	pkt.server.instance = cpu_to_le32(srv->instance);
+	pkt.server.node = cpu_to_le32(srv->node);
+	pkt.server.port = cpu_to_le32(srv->port);
+
+	msg.msg_name = (struct sockaddr *)dest;
+	msg.msg_namelen = sizeof(*dest);
+
+	return kernel_sendmsg(qrtr_ns.sock, &msg, &iv, 1, sizeof(pkt));
+}
+
+static int service_announce_del(struct sockaddr_qrtr *dest,
+				struct qrtr_server *srv)
+{
+	struct qrtr_ctrl_pkt pkt;
+	struct msghdr msg = { };
+	struct kvec iv = { &pkt, sizeof(pkt) };
+	int ret;
+
+	trace_printk("advertising removal of server [%d:%x]@[%d:%d]\n",
+		     srv->service, srv->instance, srv->node, srv->port);
+
+	memset(&pkt, 0, sizeof(pkt));
+	pkt.cmd = cpu_to_le32(QRTR_TYPE_DEL_SERVER);
+	pkt.server.service = cpu_to_le32(srv->service);
+	pkt.server.instance = cpu_to_le32(srv->instance);
+	pkt.server.node = cpu_to_le32(srv->node);
+	pkt.server.port = cpu_to_le32(srv->port);
+
+	msg.msg_name = (struct sockaddr *)dest;
+	msg.msg_namelen = sizeof(*dest);
+
+	ret = kernel_sendmsg(qrtr_ns.sock, &msg, &iv, 1, sizeof(pkt));
+	if (ret < 0)
+		pr_err("failed to announce del serivce\n");
+
+	return ret;
+}
+
+static void lookup_notify(struct sockaddr_qrtr *to, struct qrtr_server *srv,
+			  bool new)
+{
+	struct qrtr_ctrl_pkt pkt;
+	struct msghdr msg = { };
+	struct kvec iv = { &pkt, sizeof(pkt) };
+	int ret;
+
+	memset(&pkt, 0, sizeof(pkt));
+	pkt.cmd = new ? cpu_to_le32(QRTR_TYPE_NEW_SERVER) :
+			cpu_to_le32(QRTR_TYPE_DEL_SERVER);
+	if (srv) {
+		pkt.server.service = cpu_to_le32(srv->service);
+		pkt.server.instance = cpu_to_le32(srv->instance);
+		pkt.server.node = cpu_to_le32(srv->node);
+		pkt.server.port = cpu_to_le32(srv->port);
+	}
+
+	msg.msg_name = (struct sockaddr *)to;
+	msg.msg_namelen = sizeof(*to);
+
+	ret = kernel_sendmsg(qrtr_ns.sock, &msg, &iv, 1, sizeof(pkt));
+	if (ret < 0)
+		pr_err("failed to send lookup notification\n");
+}
+
+static int announce_servers(struct sockaddr_qrtr *sq)
+{
+	struct qrtr_server *srv;
+	void __rcu **slot;
+	struct radix_tree_iter iter;
+	struct qrtr_node *node;
+	int ret;
+
+	node = node_get(qrtr_ns.local_node);
+	if (!node)
+		return 0;
+
+	/* Announce the list of servers registered in this node */
+	radix_tree_for_each_slot(slot, &node->servers, &iter, 0) {
+		srv = radix_tree_deref_slot(slot);
+
+		ret = service_announce_new(sq, srv);
+		if (ret < 0) {
+			pr_err("failed to announce new service\n");
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static struct qrtr_server *server_add(unsigned int service,
+				      unsigned int instance,
+				      unsigned int node_id,
+				      unsigned int port)
+{
+	struct qrtr_server *srv;
+	struct qrtr_server *old;
+	struct qrtr_node *node;
+
+	if (!service || !port)
+		return NULL;
+
+	srv = kzalloc(sizeof(*srv), GFP_KERNEL);
+	if (!srv)
+		return ERR_PTR(-ENOMEM);
+
+	srv->service = service;
+	srv->instance = instance;
+	srv->node = node_id;
+	srv->port = port;
+
+	node = node_get(node_id);
+	if (!node)
+		goto err;
+
+	/* Delete the old server on the same port */
+	old = radix_tree_lookup(&node->servers, port);
+	if (old) {
+		radix_tree_delete(&node->servers, port);
+		kfree(old);
+	}
+
+	radix_tree_insert(&node->servers, port, srv);
+
+	trace_printk("add server [%d:%x]@[%d:%d]\n", srv->service,
+		     srv->instance, srv->node, srv->port);
+
+	return srv;
+
+err:
+	kfree(srv);
+	return NULL;
+}
+
+static int server_del(struct qrtr_node *node, unsigned int port)
+{
+	struct qrtr_lookup *lookup;
+	struct list_head *li;
+	struct qrtr_server *srv;
+
+	srv = radix_tree_lookup(&node->servers, port);
+	if (!srv)
+		return -ENOENT;
+
+	radix_tree_delete(&node->servers, port);
+
+	/* Broadcast the removal of local servers */
+	if (srv->node == qrtr_ns.local_node)
+		service_announce_del(&qrtr_ns.bcast_sq, srv);
+
+	/* Announce the service's disappearance to observers */
+	list_for_each(li, &qrtr_ns.lookups) {
+		lookup = container_of(li, struct qrtr_lookup, li);
+		if (lookup->service && lookup->service != srv->service)
+			continue;
+		if (lookup->instance && lookup->instance != srv->instance)
+			continue;
+
+		lookup_notify(&lookup->sq, srv, false);
+	}
+
+	kfree(srv);
+
+	return 0;
+}
+
+/* Announce the list of servers registered on the local node */
+static int ctrl_cmd_hello(struct sockaddr_qrtr *sq)
+{
+	return announce_servers(sq);
+}
+
+static int ctrl_cmd_bye(struct sockaddr_qrtr *from)
+{
+	struct qrtr_ctrl_pkt pkt;
+	struct kvec iv = { &pkt, sizeof(pkt) };
+	struct msghdr msg = { };
+	struct sockaddr_qrtr sq;
+	struct qrtr_node *local_node;
+	struct qrtr_server *srv;
+	struct qrtr_node *node;
+	void __rcu **slot;
+	struct radix_tree_iter iter;
+	int ret;
+
+	node = node_get(from->sq_node);
+	if (!node)
+		return 0;
+
+	/* Advertise removal of this client to all servers of remote node */
+	radix_tree_for_each_slot(slot, &node->servers, &iter, 0) {
+		srv = radix_tree_deref_slot(slot);
+		server_del(node, srv->port);
+	}
+
+	/* Advertise the removal of this client to all local servers */
+	local_node = node_get(qrtr_ns.local_node);
+	if (!local_node)
+		return 0;
+
+	memset(&pkt, 0, sizeof(pkt));
+	pkt.cmd = cpu_to_le32(QRTR_TYPE_BYE);
+	pkt.client.node = cpu_to_le32(from->sq_node);
+
+	radix_tree_for_each_slot(slot, &local_node->servers, &iter, 0) {
+		srv = radix_tree_deref_slot(slot);
+
+		sq.sq_family = AF_QIPCRTR;
+		sq.sq_node = srv->node;
+		sq.sq_port = srv->port;
+
+		msg.msg_name = (struct sockaddr *)&sq;
+		msg.msg_namelen = sizeof(sq);
+
+		ret = kernel_sendmsg(qrtr_ns.sock, &msg, &iv, 1, sizeof(pkt));
+		if (ret < 0) {
+			pr_err("failed to send bye cmd\n");
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int ctrl_cmd_del_client(struct sockaddr_qrtr *from,
+			       unsigned int node_id, unsigned int port)
+{
+	struct qrtr_ctrl_pkt pkt;
+	struct kvec iv = { &pkt, sizeof(pkt) };
+	struct msghdr msg = { };
+	struct sockaddr_qrtr sq;
+	struct qrtr_node *local_node;
+	struct list_head *tmp;
+	struct qrtr_lookup *lookup;
+	struct list_head *li;
+	struct qrtr_server *srv;
+	struct qrtr_node *node;
+	void __rcu **slot;
+	struct radix_tree_iter iter;
+	int ret;
+
+	/* Don't accept spoofed messages */
+	if (from->sq_node != node_id)
+		return -EINVAL;
+
+	/* Local DEL_CLIENT messages comes from the port being closed */
+	if (from->sq_node == qrtr_ns.local_node && from->sq_port != port)
+		return -EINVAL;
+
+	/* Remove any lookups by this client */
+	list_for_each_safe(li, tmp, &qrtr_ns.lookups) {
+		lookup = container_of(li, struct qrtr_lookup, li);
+		if (lookup->sq.sq_node != node_id)
+			continue;
+		if (lookup->sq.sq_port != port)
+			continue;
+
+		list_del(&lookup->li);
+		kfree(lookup);
+	}
+
+	/* Remove the server belonging to this port */
+	node = node_get(node_id);
+	if (node)
+		server_del(node, port);
+
+	/* Advertise the removal of this client to all local servers */
+	local_node = node_get(qrtr_ns.local_node);
+	if (!local_node)
+		return 0;
+
+	memset(&pkt, 0, sizeof(pkt));
+	pkt.cmd = cpu_to_le32(QRTR_TYPE_DEL_CLIENT);
+	pkt.client.node = cpu_to_le32(node_id);
+	pkt.client.port = cpu_to_le32(port);
+
+	radix_tree_for_each_slot(slot, &local_node->servers, &iter, 0) {
+		srv = radix_tree_deref_slot(slot);
+
+		sq.sq_family = AF_QIPCRTR;
+		sq.sq_node = srv->node;
+		sq.sq_port = srv->port;
+
+		msg.msg_name = (struct sockaddr *)&sq;
+		msg.msg_namelen = sizeof(sq);
+
+		ret = kernel_sendmsg(qrtr_ns.sock, &msg, &iv, 1, sizeof(pkt));
+		if (ret < 0) {
+			pr_err("failed to send del client cmd\n");
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int ctrl_cmd_new_server(struct sockaddr_qrtr *from,
+			       unsigned int service, unsigned int instance,
+			       unsigned int node_id, unsigned int port)
+{
+	struct qrtr_lookup *lookup;
+	struct list_head *li;
+	struct qrtr_server *srv;
+	int ret = 0;
+
+	/* Ignore specified node and port for local servers */
+	if (from->sq_node == qrtr_ns.local_node) {
+		node_id = from->sq_node;
+		port = from->sq_port;
+	}
+
+	/* Don't accept spoofed messages */
+	if (from->sq_node != node_id)
+		return -EINVAL;
+
+	srv = server_add(service, instance, node_id, port);
+	if (!srv)
+		return -EINVAL;
+
+	if (srv->node == qrtr_ns.local_node) {
+		ret = service_announce_new(&qrtr_ns.bcast_sq, srv);
+		if (ret < 0) {
+			pr_err("failed to announce new service\n");
+			return ret;
+		}
+	}
+
+	/* Notify any potential lookups about the new server */
+	list_for_each(li, &qrtr_ns.lookups) {
+		lookup = container_of(li, struct qrtr_lookup, li);
+		if (lookup->service && lookup->service != service)
+			continue;
+		if (lookup->instance && lookup->instance != instance)
+			continue;
+
+		lookup_notify(&lookup->sq, srv, true);
+	}
+
+	return ret;
+}
+
+static int ctrl_cmd_del_server(struct sockaddr_qrtr *from,
+			       unsigned int service, unsigned int instance,
+			       unsigned int node_id, unsigned int port)
+{
+	struct qrtr_node *node;
+
+	/* Ignore specified node and port for local servers */
+	if (from->sq_node == qrtr_ns.local_node) {
+		node_id = from->sq_node;
+		port = from->sq_port;
+	}
+
+	/* Don't accept spoofed messages */
+	if (from->sq_node != node_id)
+		return -EINVAL;
+
+	/* Local servers may only unregister themselves */
+	if (from->sq_node == qrtr_ns.local_node && from->sq_port != port)
+		return -EINVAL;
+
+	node = node_get(node_id);
+	if (!node)
+		return -ENOENT;
+
+	return server_del(node, port);
+}
+
+static int ctrl_cmd_new_lookup(struct sockaddr_qrtr *from,
+			       unsigned int service, unsigned int instance)
+{
+	struct qrtr_server_filter filter;
+	struct qrtr_lookup *lookup;
+	struct qrtr_node *node;
+	void __rcu **node_slot;
+	void __rcu **srv_slot;
+	struct radix_tree_iter node_iter;
+	struct radix_tree_iter srv_iter;
+
+	/* Accept only local observers */
+	if (from->sq_node != qrtr_ns.local_node)
+		return -EINVAL;
+
+	lookup = kzalloc(sizeof(*lookup), GFP_KERNEL);
+	if (!lookup)
+		return -ENOMEM;
+
+	lookup->sq = *from;
+	lookup->service = service;
+	lookup->instance = instance;
+	list_add_tail(&lookup->li, &qrtr_ns.lookups);
+
+	memset(&filter, 0, sizeof(filter));
+	filter.service = service;
+	filter.instance = instance;
+
+	radix_tree_for_each_slot(node_slot, &nodes, &node_iter, 0) {
+		node = radix_tree_deref_slot(node_slot);
+
+		radix_tree_for_each_slot(srv_slot, &node->servers,
+					 &srv_iter, 0) {
+			struct qrtr_server *srv;
+
+			srv = radix_tree_deref_slot(srv_slot);
+			if (!server_match(srv, &filter))
+				continue;
+
+			lookup_notify(from, srv, true);
+		}
+	}
+
+	/* Empty notification, to indicate end of listing */
+	lookup_notify(from, NULL, true);
+
+	return 0;
+}
+
+static void ctrl_cmd_del_lookup(struct sockaddr_qrtr *from,
+				unsigned int service, unsigned int instance)
+{
+	struct qrtr_lookup *lookup;
+	struct list_head *tmp;
+	struct list_head *li;
+
+	list_for_each_safe(li, tmp, &qrtr_ns.lookups) {
+		lookup = container_of(li, struct qrtr_lookup, li);
+		if (lookup->sq.sq_node != from->sq_node)
+			continue;
+		if (lookup->sq.sq_port != from->sq_port)
+			continue;
+		if (lookup->service != service)
+			continue;
+		if (lookup->instance && lookup->instance != instance)
+			continue;
+
+		list_del(&lookup->li);
+		kfree(lookup);
+	}
+}
+
+static int say_hello(void)
+{
+	struct qrtr_ctrl_pkt pkt;
+	struct kvec iv = { &pkt, sizeof(pkt) };
+	struct msghdr msg = { };
+	int ret;
+
+	memset(&pkt, 0, sizeof(pkt));
+	pkt.cmd = cpu_to_le32(QRTR_TYPE_HELLO);
+
+	msg.msg_name = (struct sockaddr *)&qrtr_ns.bcast_sq;
+	msg.msg_namelen = sizeof(qrtr_ns.bcast_sq);
+
+	ret = kernel_sendmsg(qrtr_ns.sock, &msg, &iv, 1, sizeof(pkt));
+	if (ret < 0)
+		pr_err("failed to send hello msg\n");
+
+	return ret;
+}
+
+static void qrtr_ns_worker(struct work_struct *work)
+{
+	const struct qrtr_ctrl_pkt *pkt;
+	struct kvec iv;
+	struct sockaddr_qrtr sq;
+	struct msghdr msg = { &sq, sizeof(sq) };
+	ssize_t msglen;
+	unsigned int cmd;
+	void *recv_buf;
+	size_t recv_buf_size = 4096;
+	int ret;
+
+	recv_buf = kzalloc(recv_buf_size, GFP_KERNEL);
+	if (!recv_buf)
+		return;
+
+	for (;;) {
+		iv.iov_base = recv_buf;
+		iv.iov_len = recv_buf_size;
+
+		msglen = kernel_recvmsg(qrtr_ns.sock, &msg, &iv, 1,
+					iv.iov_len, MSG_DONTWAIT);
+
+		if (msglen == -EAGAIN)
+			break;
+
+		if (msglen < 0) {
+			pr_err("error receiving packet: %zd\n", msglen);
+			break;
+		}
+
+		pkt = recv_buf;
+		cmd = le32_to_cpu(pkt->cmd);
+		if (cmd < ARRAY_SIZE(qrtr_ctrl_pkt_strings) &&
+		    qrtr_ctrl_pkt_strings[cmd])
+			trace_printk("%s from %d:%d\n",
+				     qrtr_ctrl_pkt_strings[cmd], sq.sq_node,
+				     sq.sq_port);
+
+		ret = 0;
+		switch (cmd) {
+		case QRTR_TYPE_HELLO:
+			ret = ctrl_cmd_hello(&sq);
+			break;
+		case QRTR_TYPE_BYE:
+			ret = ctrl_cmd_bye(&sq);
+			break;
+		case QRTR_TYPE_DEL_CLIENT:
+			ret = ctrl_cmd_del_client(&sq,
+					le32_to_cpu(pkt->client.node),
+					le32_to_cpu(pkt->client.port));
+			break;
+		case QRTR_TYPE_NEW_SERVER:
+			ret = ctrl_cmd_new_server(&sq,
+					le32_to_cpu(pkt->server.service),
+					le32_to_cpu(pkt->server.instance),
+					le32_to_cpu(pkt->server.node),
+					le32_to_cpu(pkt->server.port));
+			break;
+		case QRTR_TYPE_DEL_SERVER:
+			ret = ctrl_cmd_del_server(&sq,
+					 le32_to_cpu(pkt->server.service),
+					 le32_to_cpu(pkt->server.instance),
+					 le32_to_cpu(pkt->server.node),
+					 le32_to_cpu(pkt->server.port));
+			break;
+		case QRTR_TYPE_EXIT:
+		case QRTR_TYPE_PING:
+		case QRTR_TYPE_RESUME_TX:
+			break;
+		case QRTR_TYPE_NEW_LOOKUP:
+			ret = ctrl_cmd_new_lookup(&sq,
+					 le32_to_cpu(pkt->server.service),
+					 le32_to_cpu(pkt->server.instance));
+			break;
+		case QRTR_TYPE_DEL_LOOKUP:
+			ctrl_cmd_del_lookup(&sq,
+				    le32_to_cpu(pkt->server.service),
+				    le32_to_cpu(pkt->server.instance));
+			break;
+		}
+
+		if (ret < 0)
+			pr_err("failed while handling packet from %d:%d",
+			       sq.sq_node, sq.sq_port);
+	}
+
+	kfree(recv_buf);
+}
+
+static void qrtr_ns_data_ready(struct sock *sk)
+{
+	queue_work(qrtr_ns.workqueue, &qrtr_ns.work);
+}
+
+void qrtr_ns_init(struct work_struct *work)
+{
+	struct sockaddr_qrtr sq;
+	int ret;
+
+	INIT_LIST_HEAD(&qrtr_ns.lookups);
+	INIT_WORK(&qrtr_ns.work, qrtr_ns_worker);
+
+	ret = sock_create_kern(&init_net, AF_QIPCRTR, SOCK_DGRAM,
+			       PF_QIPCRTR, &qrtr_ns.sock);
+	if (ret < 0)
+		return;
+
+	ret = kernel_getsockname(qrtr_ns.sock, (struct sockaddr *)&sq);
+	if (ret < 0) {
+		pr_err("failed to get socket name\n");
+		goto err_sock;
+	}
+
+	qrtr_ns.sock->sk->sk_data_ready = qrtr_ns_data_ready;
+
+	sq.sq_port = QRTR_PORT_CTRL;
+	qrtr_ns.local_node = sq.sq_node;
+
+	ret = kernel_bind(qrtr_ns.sock, (struct sockaddr *)&sq, sizeof(sq));
+	if (ret < 0) {
+		pr_err("failed to bind to socket\n");
+		goto err_sock;
+	}
+
+	qrtr_ns.bcast_sq.sq_family = AF_QIPCRTR;
+	qrtr_ns.bcast_sq.sq_node = QRTR_NODE_BCAST;
+	qrtr_ns.bcast_sq.sq_port = QRTR_PORT_CTRL;
+
+	qrtr_ns.workqueue = alloc_workqueue("qrtr_ns_handler", WQ_UNBOUND, 1);
+	if (!qrtr_ns.workqueue)
+		goto err_sock;
+
+	ret = say_hello();
+	if (ret < 0)
+		goto err_wq;
+
+	return;
+
+err_wq:
+	destroy_workqueue(qrtr_ns.workqueue);
+err_sock:
+	sock_release(qrtr_ns.sock);
+}
+EXPORT_SYMBOL_GPL(qrtr_ns_init);
+
+void qrtr_ns_remove(void)
+{
+	cancel_work_sync(&qrtr_ns.work);
+	destroy_workqueue(qrtr_ns.workqueue);
+	sock_release(qrtr_ns.sock);
+}
+EXPORT_SYMBOL_GPL(qrtr_ns_remove);
+
+MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>");
+MODULE_DESCRIPTION("Qualcomm IPC Router Nameservice");
+MODULE_LICENSE("Dual BSD/GPL");
diff --git a/net/qrtr/qrtr.c b/net/qrtr/qrtr.c
index 3d24d45be5f4..e97d20640de3 100644
--- a/net/qrtr/qrtr.c
+++ b/net/qrtr/qrtr.c
@@ -8,6 +8,7 @@
 #include <linux/qrtr.h>
 #include <linux/termios.h>	/* For TIOCINQ/OUTQ */
 #include <linux/numa.h>
+#include <linux/workqueue.h>
 
 #include <net/sock.h>
 
@@ -107,6 +108,8 @@ static DEFINE_MUTEX(qrtr_node_lock);
 static DEFINE_IDR(qrtr_ports);
 static DEFINE_MUTEX(qrtr_port_lock);
 
+static struct delayed_work qrtr_ns_work;
+
 /**
  * struct qrtr_node - endpoint node
  * @ep_lock: lock for endpoint management and callbacks
@@ -1066,38 +1069,6 @@ static int qrtr_create(struct net *net, struct socket *sock,
 	return 0;
 }
 
-static const struct nla_policy qrtr_policy[IFA_MAX + 1] = {
-	[IFA_LOCAL] = { .type = NLA_U32 },
-};
-
-static int qrtr_addr_doit(struct sk_buff *skb, struct nlmsghdr *nlh,
-			  struct netlink_ext_ack *extack)
-{
-	struct nlattr *tb[IFA_MAX + 1];
-	struct ifaddrmsg *ifm;
-	int rc;
-
-	if (!netlink_capable(skb, CAP_NET_ADMIN))
-		return -EPERM;
-
-	if (!netlink_capable(skb, CAP_SYS_ADMIN))
-		return -EPERM;
-
-	ASSERT_RTNL();
-
-	rc = nlmsg_parse_deprecated(nlh, sizeof(*ifm), tb, IFA_MAX,
-				    qrtr_policy, extack);
-	if (rc < 0)
-		return rc;
-
-	ifm = nlmsg_data(nlh);
-	if (!tb[IFA_LOCAL])
-		return -EINVAL;
-
-	qrtr_local_nid = nla_get_u32(tb[IFA_LOCAL]);
-	return 0;
-}
-
 static const struct net_proto_family qrtr_family = {
 	.owner	= THIS_MODULE,
 	.family	= AF_QIPCRTR,
@@ -1118,11 +1089,11 @@ static int __init qrtr_proto_init(void)
 		return rc;
 	}
 
-	rc = rtnl_register_module(THIS_MODULE, PF_QIPCRTR, RTM_NEWADDR, qrtr_addr_doit, NULL, 0);
-	if (rc) {
-		sock_unregister(qrtr_family.family);
-		proto_unregister(&qrtr_proto);
-	}
+	/* FIXME: Currently, this 2s delay is required to catch the NEW_SERVER
+	 * messages from routers. But the fix could be somewhere else.
+	 */
+	INIT_DELAYED_WORK(&qrtr_ns_work, qrtr_ns_init);
+	schedule_delayed_work(&qrtr_ns_work, msecs_to_jiffies(2000));
 
 	return rc;
 }
@@ -1130,7 +1101,8 @@ postcore_initcall(qrtr_proto_init);
 
 static void __exit qrtr_proto_fini(void)
 {
-	rtnl_unregister(PF_QIPCRTR, RTM_NEWADDR);
+	cancel_delayed_work_sync(&qrtr_ns_work);
+	qrtr_ns_remove();
 	sock_unregister(qrtr_family.family);
 	proto_unregister(&qrtr_proto);
 }
diff --git a/net/qrtr/qrtr.h b/net/qrtr/qrtr.h
index b81e6953c04b..53a237a28971 100644
--- a/net/qrtr/qrtr.h
+++ b/net/qrtr/qrtr.h
@@ -29,4 +29,8 @@ void qrtr_endpoint_unregister(struct qrtr_endpoint *ep);
 
 int qrtr_endpoint_post(struct qrtr_endpoint *ep, const void *data, size_t len);
 
+void qrtr_ns_init(struct work_struct *work);
+
+void qrtr_ns_remove(void);
+
 #endif
-- 
2.17.1