[PATCH v2 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. Since the QRTR NS is not usually
packed in most of the distros, users need to clone, build and install it
to get the WiFi working. It will become a hassle when the user doesn't
have any other source of network connectivity.

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@xxxxxxxxxx>
---
 net/qrtr/Makefile |   2 +-
 net/qrtr/ns.c     | 751 ++++++++++++++++++++++++++++++++++++++++++++++
 net/qrtr/qrtr.c   |  48 +--
 net/qrtr/qrtr.h   |   4 +
 4 files changed, 766 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..67a4e59cdf4d
--- /dev/null
+++ b/net/qrtr/ns.c
@@ -0,0 +1,751 @@
+// 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;
+
+	trace_printk("advertising new server [%d:%x]@[%d:%d]\n",
+		     srv->service, srv->instance, srv->node, srv->port);
+
+	iv.iov_base = &pkt;
+	iv.iov_len = sizeof(pkt);
+
+	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;
+	int ret;
+
+	trace_printk("advertising removal of server [%d:%x]@[%d:%d]\n",
+		     srv->service, srv->instance, srv->node, srv->port);
+
+	iv.iov_base = &pkt;
+	iv.iov_len = sizeof(pkt);
+
+	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;
+	int ret;
+
+	iv.iov_base = &pkt;
+	iv.iov_len = sizeof(pkt);
+
+	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 radix_tree_iter iter;
+	struct qrtr_server *srv;
+	struct qrtr_node *node;
+	void __rcu **slot;
+	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 qrtr_server *srv;
+	struct list_head *li;
+
+	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_node *local_node;
+	struct radix_tree_iter iter;
+	struct qrtr_ctrl_pkt pkt;
+	struct qrtr_server *srv;
+	struct sockaddr_qrtr sq;
+	struct msghdr msg = { };
+	struct qrtr_node *node;
+	void __rcu **slot;
+	struct kvec iv;
+	int ret;
+
+	iv.iov_base = &pkt;
+	iv.iov_len = sizeof(pkt);
+
+	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_node *local_node;
+	struct radix_tree_iter iter;
+	struct qrtr_lookup *lookup;
+	struct qrtr_ctrl_pkt pkt;
+	struct msghdr msg = { };
+	struct qrtr_server *srv;
+	struct sockaddr_qrtr sq;
+	struct qrtr_node *node;
+	struct list_head *tmp;
+	struct list_head *li;
+	void __rcu **slot;
+	struct kvec iv;
+	int ret;
+
+	iv.iov_base = &pkt;
+	iv.iov_len = sizeof(pkt);
+
+	/* 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 qrtr_server *srv;
+	struct list_head *li;
+	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 radix_tree_iter node_iter;
+	struct qrtr_server_filter filter;
+	struct radix_tree_iter srv_iter;
+	struct qrtr_lookup *lookup;
+	struct qrtr_node *node;
+	void __rcu **node_slot;
+	void __rcu **srv_slot;
+
+	/* 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 msghdr msg = { };
+	struct kvec iv;
+	int ret;
+
+	iv.iov_base = &pkt;
+	iv.iov_len = sizeof(pkt);
+
+	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;
+	size_t recv_buf_size = 4096;
+	struct sockaddr_qrtr sq;
+	struct msghdr msg = { };
+	unsigned int cmd;
+	ssize_t msglen;
+	void *recv_buf;
+	struct kvec iv;
+	int ret;
+
+	msg.msg_name = (struct sockaddr *)&sq;
+	msg.msg_namelen = sizeof(sq);
+
+	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 5a8e42ad1504..c758383ba866 100644
--- a/net/qrtr/qrtr.c
+++ b/net/qrtr/qrtr.c
@@ -10,6 +10,7 @@
 #include <linux/numa.h>
 #include <linux/spinlock.h>
 #include <linux/wait.h>
+#include <linux/workqueue.h>
 
 #include <net/sock.h>
 
@@ -110,6 +111,8 @@ 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
@@ -1241,38 +1244,6 @@ 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,
@@ -1293,11 +1264,11 @@ 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;
 }
@@ -1305,7 +1276,8 @@ 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