diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index 08b85215c2be98782f80acadd9302d85e1489dac..8918466550004dbf14c2e15f2ab25d7aa2317af5 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -500,6 +500,7 @@ source "drivers/net/hyperv/Kconfig"
 config NETDEVSIM
 	tristate "Simulated networking device"
 	depends on DEBUG_FS
+	depends on MAY_USE_DEVLINK
 	help
 	  This driver is a developer testing tool and software model that can
 	  be used to test various control path networking APIs, especially
diff --git a/drivers/net/netdevsim/Makefile b/drivers/net/netdevsim/Makefile
index 09388c06171ddeaf2fb51df0da5293342cc88dd3..449b2a1a18007e49c8d55993433cf865db893577 100644
--- a/drivers/net/netdevsim/Makefile
+++ b/drivers/net/netdevsim/Makefile
@@ -9,3 +9,7 @@ ifeq ($(CONFIG_BPF_SYSCALL),y)
 netdevsim-objs += \
 	bpf.o
 endif
+
+ifneq ($(CONFIG_NET_DEVLINK),)
+netdevsim-objs += devlink.o fib.o
+endif
diff --git a/drivers/net/netdevsim/devlink.c b/drivers/net/netdevsim/devlink.c
new file mode 100644
index 0000000000000000000000000000000000000000..bbdcf064ba1048e42fb25c63674af7941fbf5104
--- /dev/null
+++ b/drivers/net/netdevsim/devlink.c
@@ -0,0 +1,294 @@
+/*
+ * Copyright (c) 2018 Cumulus Networks. All rights reserved.
+ * Copyright (c) 2018 David Ahern <dsa@cumulusnetworks.com>
+ *
+ * This software is licensed under the GNU General License Version 2,
+ * June 1991 as shown in the file COPYING in the top-level directory of this
+ * source tree.
+ *
+ * THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS"
+ * WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING,
+ * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE
+ * OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME
+ * THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+ */
+
+#include <linux/device.h>
+#include <net/devlink.h>
+#include <net/netns/generic.h>
+
+#include "netdevsim.h"
+
+static unsigned int nsim_devlink_id;
+
+/* place holder until devlink and namespaces is sorted out */
+static struct net *nsim_devlink_net(struct devlink *devlink)
+{
+	return &init_net;
+}
+
+/* IPv4
+ */
+static u64 nsim_ipv4_fib_resource_occ_get(struct devlink *devlink)
+{
+	struct net *net = nsim_devlink_net(devlink);
+
+	return nsim_fib_get_val(net, NSIM_RESOURCE_IPV4_FIB, false);
+}
+
+static struct devlink_resource_ops nsim_ipv4_fib_res_ops = {
+	.occ_get = nsim_ipv4_fib_resource_occ_get,
+};
+
+static u64 nsim_ipv4_fib_rules_res_occ_get(struct devlink *devlink)
+{
+	struct net *net = nsim_devlink_net(devlink);
+
+	return nsim_fib_get_val(net, NSIM_RESOURCE_IPV4_FIB_RULES, false);
+}
+
+static struct devlink_resource_ops nsim_ipv4_fib_rules_res_ops = {
+	.occ_get = nsim_ipv4_fib_rules_res_occ_get,
+};
+
+/* IPv6
+ */
+static u64 nsim_ipv6_fib_resource_occ_get(struct devlink *devlink)
+{
+	struct net *net = nsim_devlink_net(devlink);
+
+	return nsim_fib_get_val(net, NSIM_RESOURCE_IPV6_FIB, false);
+}
+
+static struct devlink_resource_ops nsim_ipv6_fib_res_ops = {
+	.occ_get = nsim_ipv6_fib_resource_occ_get,
+};
+
+static u64 nsim_ipv6_fib_rules_res_occ_get(struct devlink *devlink)
+{
+	struct net *net = nsim_devlink_net(devlink);
+
+	return nsim_fib_get_val(net, NSIM_RESOURCE_IPV6_FIB_RULES, false);
+}
+
+static struct devlink_resource_ops nsim_ipv6_fib_rules_res_ops = {
+	.occ_get = nsim_ipv6_fib_rules_res_occ_get,
+};
+
+static int devlink_resources_register(struct devlink *devlink)
+{
+	struct devlink_resource_size_params params = {
+		.size_max = (u64)-1,
+		.size_granularity = 1,
+		.unit = DEVLINK_RESOURCE_UNIT_ENTRY
+	};
+	struct net *net = nsim_devlink_net(devlink);
+	int err;
+	u64 n;
+
+	/* Resources for IPv4 */
+	err = devlink_resource_register(devlink, "IPv4", (u64)-1,
+					NSIM_RESOURCE_IPV4,
+					DEVLINK_RESOURCE_ID_PARENT_TOP,
+					&params, NULL);
+	if (err) {
+		pr_err("Failed to register IPv4 top resource\n");
+		goto out;
+	}
+
+	n = nsim_fib_get_val(net, NSIM_RESOURCE_IPV4_FIB, true);
+	err = devlink_resource_register(devlink, "fib", n,
+					NSIM_RESOURCE_IPV4_FIB,
+					NSIM_RESOURCE_IPV4,
+					&params, &nsim_ipv4_fib_res_ops);
+	if (err) {
+		pr_err("Failed to register IPv4 FIB resource\n");
+		return err;
+	}
+
+	n = nsim_fib_get_val(net, NSIM_RESOURCE_IPV4_FIB_RULES, true);
+	err = devlink_resource_register(devlink, "fib-rules", n,
+					NSIM_RESOURCE_IPV4_FIB_RULES,
+					NSIM_RESOURCE_IPV4,
+					&params, &nsim_ipv4_fib_rules_res_ops);
+	if (err) {
+		pr_err("Failed to register IPv4 FIB rules resource\n");
+		return err;
+	}
+
+	/* Resources for IPv6 */
+	err = devlink_resource_register(devlink, "IPv6", (u64)-1,
+					NSIM_RESOURCE_IPV6,
+					DEVLINK_RESOURCE_ID_PARENT_TOP,
+					&params, NULL);
+	if (err) {
+		pr_err("Failed to register IPv6 top resource\n");
+		goto out;
+	}
+
+	n = nsim_fib_get_val(net, NSIM_RESOURCE_IPV6_FIB, true);
+	err = devlink_resource_register(devlink, "fib", n,
+					NSIM_RESOURCE_IPV6_FIB,
+					NSIM_RESOURCE_IPV6,
+					&params, &nsim_ipv6_fib_res_ops);
+	if (err) {
+		pr_err("Failed to register IPv6 FIB resource\n");
+		return err;
+	}
+
+	n = nsim_fib_get_val(net, NSIM_RESOURCE_IPV6_FIB_RULES, true);
+	err = devlink_resource_register(devlink, "fib-rules", n,
+					NSIM_RESOURCE_IPV6_FIB_RULES,
+					NSIM_RESOURCE_IPV6,
+					&params, &nsim_ipv6_fib_rules_res_ops);
+	if (err) {
+		pr_err("Failed to register IPv6 FIB rules resource\n");
+		return err;
+	}
+out:
+	return err;
+}
+
+static int nsim_devlink_reload(struct devlink *devlink)
+{
+	enum nsim_resource_id res_ids[] = {
+		NSIM_RESOURCE_IPV4_FIB, NSIM_RESOURCE_IPV4_FIB_RULES,
+		NSIM_RESOURCE_IPV6_FIB, NSIM_RESOURCE_IPV6_FIB_RULES
+	};
+	struct net *net = nsim_devlink_net(devlink);
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(res_ids); ++i) {
+		int err;
+		u64 val;
+
+		err = devlink_resource_size_get(devlink, res_ids[i], &val);
+		if (!err) {
+			err = nsim_fib_set_max(net, res_ids[i], val);
+			if (err)
+				return err;
+		}
+	}
+
+	return 0;
+}
+
+static void nsim_devlink_net_reset(struct net *net)
+{
+	enum nsim_resource_id res_ids[] = {
+		NSIM_RESOURCE_IPV4_FIB, NSIM_RESOURCE_IPV4_FIB_RULES,
+		NSIM_RESOURCE_IPV6_FIB, NSIM_RESOURCE_IPV6_FIB_RULES
+	};
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(res_ids); ++i) {
+		if (nsim_fib_set_max(net, res_ids[i], (u64)-1)) {
+			pr_err("Failed to reset limit for resource %u\n",
+			       res_ids[i]);
+		}
+	}
+}
+
+static const struct devlink_ops nsim_devlink_ops = {
+	.reload = nsim_devlink_reload,
+};
+
+/* once devlink / namespace issues are sorted out
+ * this needs to be net in which a devlink instance
+ * is to be created. e.g., dev_net(ns->netdev)
+ */
+static struct net *nsim_to_net(struct netdevsim *ns)
+{
+	return &init_net;
+}
+
+void nsim_devlink_teardown(struct netdevsim *ns)
+{
+	if (ns->devlink) {
+		struct net *net = nsim_to_net(ns);
+		bool *reg_devlink = net_generic(net, nsim_devlink_id);
+
+		devlink_unregister(ns->devlink);
+		devlink_free(ns->devlink);
+		ns->devlink = NULL;
+
+		nsim_devlink_net_reset(net);
+		*reg_devlink = true;
+	}
+}
+
+void nsim_devlink_setup(struct netdevsim *ns)
+{
+	struct net *net = nsim_to_net(ns);
+	bool *reg_devlink = net_generic(net, nsim_devlink_id);
+	struct devlink *devlink;
+	int err = -ENOMEM;
+
+	/* only one device per namespace controls devlink */
+	if (!*reg_devlink) {
+		ns->devlink = NULL;
+		return;
+	}
+
+	devlink = devlink_alloc(&nsim_devlink_ops, 0);
+	if (!devlink)
+		return;
+
+	err = devlink_register(devlink, &ns->dev);
+	if (err)
+		goto err_devlink_free;
+
+	err = devlink_resources_register(devlink);
+	if (err)
+		goto err_dl_unregister;
+
+	ns->devlink = devlink;
+
+	*reg_devlink = false;
+
+	return;
+
+err_dl_unregister:
+	devlink_unregister(devlink);
+err_devlink_free:
+	devlink_free(devlink);
+}
+
+/* Initialize per network namespace state */
+static int __net_init nsim_devlink_netns_init(struct net *net)
+{
+	bool *reg_devlink = net_generic(net, nsim_devlink_id);
+
+	*reg_devlink = true;
+
+	return 0;
+}
+
+static struct pernet_operations nsim_devlink_net_ops __net_initdata = {
+	.init = nsim_devlink_netns_init,
+	.id   = &nsim_devlink_id,
+	.size = sizeof(bool),
+};
+
+void nsim_devlink_exit(void)
+{
+	unregister_pernet_subsys(&nsim_devlink_net_ops);
+	nsim_fib_exit();
+}
+
+int nsim_devlink_init(void)
+{
+	int err;
+
+	err = nsim_fib_init();
+	if (err)
+		goto err_out;
+
+	err = register_pernet_subsys(&nsim_devlink_net_ops);
+	if (err)
+		nsim_fib_exit();
+
+err_out:
+	return err;
+}
diff --git a/drivers/net/netdevsim/fib.c b/drivers/net/netdevsim/fib.c
new file mode 100644
index 0000000000000000000000000000000000000000..0d105bafa26129e14b205c00c158c3002d8b424b
--- /dev/null
+++ b/drivers/net/netdevsim/fib.c
@@ -0,0 +1,263 @@
+/*
+ * Copyright (c) 2018 Cumulus Networks. All rights reserved.
+ * Copyright (c) 2018 David Ahern <dsa@cumulusnetworks.com>
+ *
+ * This software is licensed under the GNU General License Version 2,
+ * June 1991 as shown in the file COPYING in the top-level directory of this
+ * source tree.
+ *
+ * THE COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS"
+ * WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING,
+ * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE
+ * OF THE PROGRAM IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME
+ * THE COST OF ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+ */
+
+#include <net/fib_notifier.h>
+#include <net/ip_fib.h>
+#include <net/ip6_fib.h>
+#include <net/fib_rules.h>
+#include <net/netns/generic.h>
+
+#include "netdevsim.h"
+
+struct nsim_fib_entry {
+	u64 max;
+	u64 num;
+};
+
+struct nsim_per_fib_data {
+	struct nsim_fib_entry fib;
+	struct nsim_fib_entry rules;
+};
+
+struct nsim_fib_data {
+	struct nsim_per_fib_data ipv4;
+	struct nsim_per_fib_data ipv6;
+};
+
+static unsigned int nsim_fib_net_id;
+
+u64 nsim_fib_get_val(struct net *net, enum nsim_resource_id res_id, bool max)
+{
+	struct nsim_fib_data *fib_data = net_generic(net, nsim_fib_net_id);
+	struct nsim_fib_entry *entry;
+
+	switch (res_id) {
+	case NSIM_RESOURCE_IPV4_FIB:
+		entry = &fib_data->ipv4.fib;
+		break;
+	case NSIM_RESOURCE_IPV4_FIB_RULES:
+		entry = &fib_data->ipv4.rules;
+		break;
+	case NSIM_RESOURCE_IPV6_FIB:
+		entry = &fib_data->ipv6.fib;
+		break;
+	case NSIM_RESOURCE_IPV6_FIB_RULES:
+		entry = &fib_data->ipv6.rules;
+		break;
+	default:
+		return 0;
+	}
+
+	return max ? entry->max : entry->num;
+}
+
+int nsim_fib_set_max(struct net *net, enum nsim_resource_id res_id, u64 val)
+{
+	struct nsim_fib_data *fib_data = net_generic(net, nsim_fib_net_id);
+	struct nsim_fib_entry *entry;
+	int err = 0;
+
+	switch (res_id) {
+	case NSIM_RESOURCE_IPV4_FIB:
+		entry = &fib_data->ipv4.fib;
+		break;
+	case NSIM_RESOURCE_IPV4_FIB_RULES:
+		entry = &fib_data->ipv4.rules;
+		break;
+	case NSIM_RESOURCE_IPV6_FIB:
+		entry = &fib_data->ipv6.fib;
+		break;
+	case NSIM_RESOURCE_IPV6_FIB_RULES:
+		entry = &fib_data->ipv6.rules;
+		break;
+	default:
+		return 0;
+	}
+
+	/* not allowing a new max to be less than curren occupancy
+	 * --> no means of evicting entries
+	 */
+	if (val < entry->num)
+		err = -EINVAL;
+	else
+		entry->max = val;
+
+	return err;
+}
+
+static int nsim_fib_rule_account(struct nsim_fib_entry *entry, bool add,
+				 struct netlink_ext_ack *extack)
+{
+	int err = 0;
+
+	if (add) {
+		if (entry->num < entry->max) {
+			entry->num++;
+		} else {
+			err = -ENOSPC;
+			NL_SET_ERR_MSG_MOD(extack, "Exceeded number of supported fib rule entries");
+		}
+	} else {
+		entry->num--;
+	}
+
+	return err;
+}
+
+static int nsim_fib_rule_event(struct fib_notifier_info *info, bool add)
+{
+	struct nsim_fib_data *data = net_generic(info->net, nsim_fib_net_id);
+	struct netlink_ext_ack *extack = info->extack;
+	int err = 0;
+
+	switch (info->family) {
+	case AF_INET:
+		err = nsim_fib_rule_account(&data->ipv4.rules, add, extack);
+		break;
+	case AF_INET6:
+		err = nsim_fib_rule_account(&data->ipv6.rules, add, extack);
+		break;
+	}
+
+	return err;
+}
+
+static int nsim_fib_account(struct nsim_fib_entry *entry, bool add,
+			    struct netlink_ext_ack *extack)
+{
+	int err = 0;
+
+	if (add) {
+		if (entry->num < entry->max) {
+			entry->num++;
+		} else {
+			err = -ENOSPC;
+			NL_SET_ERR_MSG_MOD(extack, "Exceeded number of supported fib entries");
+		}
+	} else {
+		entry->num--;
+	}
+
+	return err;
+}
+
+static int nsim_fib_event(struct fib_notifier_info *info, bool add)
+{
+	struct nsim_fib_data *data = net_generic(info->net, nsim_fib_net_id);
+	struct netlink_ext_ack *extack = info->extack;
+	int err = 0;
+
+	switch (info->family) {
+	case AF_INET:
+		err = nsim_fib_account(&data->ipv4.fib, add, extack);
+		break;
+	case AF_INET6:
+		err = nsim_fib_account(&data->ipv6.fib, add, extack);
+		break;
+	}
+
+	return err;
+}
+
+static int nsim_fib_event_nb(struct notifier_block *nb, unsigned long event,
+			     void *ptr)
+{
+	struct fib_notifier_info *info = ptr;
+	int err = 0;
+
+	switch (event) {
+	case FIB_EVENT_RULE_ADD: /* fall through */
+	case FIB_EVENT_RULE_DEL:
+		err = nsim_fib_rule_event(info, event == FIB_EVENT_RULE_ADD);
+		break;
+
+	case FIB_EVENT_ENTRY_ADD:  /* fall through */
+	case FIB_EVENT_ENTRY_DEL:
+		err = nsim_fib_event(info, event == FIB_EVENT_ENTRY_ADD);
+		break;
+	}
+
+	return notifier_from_errno(err);
+}
+
+/* inconsistent dump, trying again */
+static void nsim_fib_dump_inconsistent(struct notifier_block *nb)
+{
+	struct nsim_fib_data *data;
+	struct net *net;
+
+	rcu_read_lock();
+	for_each_net_rcu(net) {
+		data = net_generic(net, nsim_fib_net_id);
+
+		data->ipv4.fib.num = 0ULL;
+		data->ipv4.rules.num = 0ULL;
+
+		data->ipv6.fib.num = 0ULL;
+		data->ipv6.rules.num = 0ULL;
+	}
+	rcu_read_unlock();
+}
+
+static struct notifier_block nsim_fib_nb = {
+	.notifier_call = nsim_fib_event_nb,
+};
+
+/* Initialize per network namespace state */
+static int __net_init nsim_fib_netns_init(struct net *net)
+{
+	struct nsim_fib_data *data = net_generic(net, nsim_fib_net_id);
+
+	data->ipv4.fib.max = (u64)-1;
+	data->ipv4.rules.max = (u64)-1;
+
+	data->ipv6.fib.max = (u64)-1;
+	data->ipv6.rules.max = (u64)-1;
+
+	return 0;
+}
+
+static struct pernet_operations nsim_fib_net_ops __net_initdata = {
+	.init = nsim_fib_netns_init,
+	.id   = &nsim_fib_net_id,
+	.size = sizeof(struct nsim_fib_data),
+};
+
+void nsim_fib_exit(void)
+{
+	unregister_pernet_subsys(&nsim_fib_net_ops);
+	unregister_fib_notifier(&nsim_fib_nb);
+}
+
+int nsim_fib_init(void)
+{
+	int err;
+
+	err = register_pernet_subsys(&nsim_fib_net_ops);
+	if (err < 0) {
+		pr_err("Failed to register pernet subsystem\n");
+		goto err_out;
+	}
+
+	err = register_fib_notifier(&nsim_fib_nb, nsim_fib_dump_inconsistent);
+	if (err < 0) {
+		pr_err("Failed to register fib notifier\n");
+		goto err_out;
+	}
+
+err_out:
+	return err;
+}
diff --git a/drivers/net/netdevsim/netdev.c b/drivers/net/netdevsim/netdev.c
index 3fd567928f3d7c7530919c95b00df398590b6d9d..8b30ab3ea2c2434f7d7a37ec6a50cff1f4c9c4f1 100644
--- a/drivers/net/netdevsim/netdev.c
+++ b/drivers/net/netdevsim/netdev.c
@@ -167,6 +167,8 @@ static int nsim_init(struct net_device *dev)
 
 	SET_NETDEV_DEV(dev, &ns->dev);
 
+	nsim_devlink_setup(ns);
+
 	return 0;
 
 err_bpf_uninit:
@@ -180,6 +182,7 @@ static void nsim_uninit(struct net_device *dev)
 {
 	struct netdevsim *ns = netdev_priv(dev);
 
+	nsim_devlink_teardown(ns);
 	debugfs_remove_recursive(ns->ddir);
 	nsim_bpf_uninit(ns);
 }
@@ -478,12 +481,18 @@ static int __init nsim_module_init(void)
 	if (err)
 		goto err_debugfs_destroy;
 
-	err = rtnl_link_register(&nsim_link_ops);
+	err = nsim_devlink_init();
 	if (err)
 		goto err_unreg_bus;
 
+	err = rtnl_link_register(&nsim_link_ops);
+	if (err)
+		goto err_dl_fini;
+
 	return 0;
 
+err_dl_fini:
+	nsim_devlink_exit();
 err_unreg_bus:
 	bus_unregister(&nsim_bus);
 err_debugfs_destroy:
@@ -494,6 +503,7 @@ static int __init nsim_module_init(void)
 static void __exit nsim_module_exit(void)
 {
 	rtnl_link_unregister(&nsim_link_ops);
+	nsim_devlink_exit();
 	bus_unregister(&nsim_bus);
 	debugfs_remove_recursive(nsim_ddir);
 }
diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h
index ea081c10efb8b30f562dabf09c9eaec26ef2fc1e..afb8cf90c0fdfae4042bf9580c6feb8df8ec5137 100644
--- a/drivers/net/netdevsim/netdevsim.h
+++ b/drivers/net/netdevsim/netdevsim.h
@@ -64,6 +64,9 @@ struct netdevsim {
 
 	bool bpf_map_accept;
 	struct list_head bpf_bound_maps;
+#if IS_ENABLED(CONFIG_NET_DEVLINK)
+	struct devlink *devlink;
+#endif
 };
 
 extern struct dentry *nsim_ddir;
@@ -103,6 +106,46 @@ nsim_bpf_setup_tc_block_cb(enum tc_setup_type type, void *type_data,
 }
 #endif
 
+#if IS_ENABLED(CONFIG_NET_DEVLINK)
+enum nsim_resource_id {
+	NSIM_RESOURCE_NONE,   /* DEVLINK_RESOURCE_ID_PARENT_TOP */
+	NSIM_RESOURCE_IPV4,
+	NSIM_RESOURCE_IPV4_FIB,
+	NSIM_RESOURCE_IPV4_FIB_RULES,
+	NSIM_RESOURCE_IPV6,
+	NSIM_RESOURCE_IPV6_FIB,
+	NSIM_RESOURCE_IPV6_FIB_RULES,
+};
+
+void nsim_devlink_setup(struct netdevsim *ns);
+void nsim_devlink_teardown(struct netdevsim *ns);
+
+int nsim_devlink_init(void);
+void nsim_devlink_exit(void);
+
+int nsim_fib_init(void);
+void nsim_fib_exit(void);
+u64 nsim_fib_get_val(struct net *net, enum nsim_resource_id res_id, bool max);
+int nsim_fib_set_max(struct net *net, enum nsim_resource_id res_id, u64 val);
+#else
+static inline void nsim_devlink_setup(struct netdevsim *ns)
+{
+}
+
+static inline void nsim_devlink_teardown(struct netdevsim *ns)
+{
+}
+
+static inline int nsim_devlink_init(void)
+{
+	return 0;
+}
+
+static inline void nsim_devlink_exit(void)
+{
+}
+#endif
+
 static inline struct netdevsim *to_nsim(struct device *ptr)
 {
 	return container_of(ptr, struct netdevsim, dev);