net/hsr/hsr_device.c - kernel/msm-4.19 - Gitiles

 /* Copyright 2011-2014 Autronica Fire and Security AS
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the Free
  * Software Foundation; either version 2 of the License, or (at your option)
  * any later version.
  *
  * Author(s):
  *	2011-2014 Arvid Brodin, arvid.brodin@alten.se
  *
  * This file contains device methods for creating, using and destroying
  * virtual HSR devices.
  */

 #include <linux/netdevice.h>
 #include <linux/skbuff.h>
 #include <linux/etherdevice.h>
 #include <linux/rtnetlink.h>
 #include <linux/pkt_sched.h>
 #include "hsr_device.h"
 #include "hsr_slave.h"
 #include "hsr_framereg.h"
 #include "hsr_main.h"
 #include "hsr_forward.h"


 static bool is_admin_up(struct net_device *dev)
 {
 	return dev && (dev->flags & IFF_UP);
 }

 static bool is_slave_up(struct net_device *dev)
 {
 	return dev && is_admin_up(dev) && netif_oper_up(dev);
 }

 static void __hsr_set_operstate(struct net_device *dev, int transition)
 {
 	write_lock_bh(&dev_base_lock);
 	if (dev->operstate != transition) {
 		dev->operstate = transition;
 		write_unlock_bh(&dev_base_lock);
 		netdev_state_change(dev);
 	} else {
 		write_unlock_bh(&dev_base_lock);
 	}
 }

 static void hsr_set_operstate(struct hsr_port *master, bool has_carrier)
 {
 	if (!is_admin_up(master->dev)) {
 		__hsr_set_operstate(master->dev, IF_OPER_DOWN);
 		return;
 	}

 	if (has_carrier)
 		__hsr_set_operstate(master->dev, IF_OPER_UP);
 	else
 		__hsr_set_operstate(master->dev, IF_OPER_LOWERLAYERDOWN);
 }

 static bool hsr_check_carrier(struct hsr_port *master)
 {
 	struct hsr_port *port;
 	bool has_carrier;

 	has_carrier = false;

 	rcu_read_lock();
 	hsr_for_each_port(master->hsr, port)
 		if ((port->type != HSR_PT_MASTER) && is_slave_up(port->dev)) {
 			has_carrier = true;
 			break;
 		}
 	rcu_read_unlock();

 	if (has_carrier)
 		netif_carrier_on(master->dev);
 	else
 		netif_carrier_off(master->dev);

 	return has_carrier;
 }


 static void hsr_check_announce(struct net_device *hsr_dev,
 			       unsigned char old_operstate)
 {
 	struct hsr_priv *hsr;

 	hsr = netdev_priv(hsr_dev);

 	if ((hsr_dev->operstate == IF_OPER_UP)
 			&& (old_operstate != IF_OPER_UP)) {
 		/* Went up */
 		hsr->announce_count = 0;
 		hsr->announce_timer.expires = jiffies +
 				msecs_to_jiffies(HSR_ANNOUNCE_INTERVAL);
 		add_timer(&hsr->announce_timer);
 	}

 	if ((hsr_dev->operstate != IF_OPER_UP) && (old_operstate == IF_OPER_UP))
 		/* Went down */
 		del_timer(&hsr->announce_timer);
 }

 void hsr_check_carrier_and_operstate(struct hsr_priv *hsr)
 {
 	struct hsr_port *master;
 	unsigned char old_operstate;
 	bool has_carrier;

 	master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
 	/* netif_stacked_transfer_operstate() cannot be used here since
 	 * it doesn't set IF_OPER_LOWERLAYERDOWN (?)
 	 */
 	old_operstate = master->dev->operstate;
 	has_carrier = hsr_check_carrier(master);
 	hsr_set_operstate(master, has_carrier);
 	hsr_check_announce(master->dev, old_operstate);
 }

 int hsr_get_max_mtu(struct hsr_priv *hsr)
 {
 	unsigned int mtu_max;
 	struct hsr_port *port;

 	mtu_max = ETH_DATA_LEN;
 	rcu_read_lock();
 	hsr_for_each_port(hsr, port)
 		if (port->type != HSR_PT_MASTER)
 			mtu_max = min(port->dev->mtu, mtu_max);
 	rcu_read_unlock();

 	if (mtu_max < HSR_HLEN)
 		return 0;
 	return mtu_max - HSR_HLEN;
 }


 static int hsr_dev_change_mtu(struct net_device *dev, int new_mtu)
 {
 	struct hsr_priv *hsr;
 	struct hsr_port *master;

 	hsr = netdev_priv(dev);
 	master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);

 	if (new_mtu > hsr_get_max_mtu(hsr)) {
 		netdev_info(master->dev, "A HSR master's MTU cannot be greater than the smallest MTU of its slaves minus the HSR Tag length (%d octets).\n",
 			    HSR_HLEN);
 		return -EINVAL;
 	}

 	dev->mtu = new_mtu;

 	return 0;
 }

 static int hsr_dev_open(struct net_device *dev)
 {
 	struct hsr_priv *hsr;
 	struct hsr_port *port;
 	char designation;

 	hsr = netdev_priv(dev);
 	designation = '\0';

 	rcu_read_lock();
 	hsr_for_each_port(hsr, port) {
 		if (port->type == HSR_PT_MASTER)
 			continue;
 		switch (port->type) {
 		case HSR_PT_SLAVE_A:
 			designation = 'A';
 			break;
 		case HSR_PT_SLAVE_B:
 			designation = 'B';
 			break;
 		default:
 			designation = '?';
 		}
 		if (!is_slave_up(port->dev))
 			netdev_warn(dev, "Slave %c (%s) is not up; please bring it up to get a fully working HSR network\n",
 				    designation, port->dev->name);
 	}
 	rcu_read_unlock();

 	if (designation == '\0')
 		netdev_warn(dev, "No slave devices configured\n");

 	return 0;
 }


 static int hsr_dev_close(struct net_device *dev)
 {
 	/* Nothing to do here. */
 	return 0;
 }


 static netdev_features_t hsr_features_recompute(struct hsr_priv *hsr,
 						netdev_features_t features)
 {
 	netdev_features_t mask;
 	struct hsr_port *port;

 	mask = features;

 	/* Mask out all features that, if supported by one device, should be
 	 * enabled for all devices (see NETIF_F_ONE_FOR_ALL).
 	 *
 	 * Anything that's off in mask will not be enabled - so only things
 	 * that were in features originally, and also is in NETIF_F_ONE_FOR_ALL,
 	 * may become enabled.
 	 */
 	features &= ~NETIF_F_ONE_FOR_ALL;
 	hsr_for_each_port(hsr, port)
 		features = netdev_increment_features(features,
 						     port->dev->features,
 						     mask);

 	return features;
 }

 static netdev_features_t hsr_fix_features(struct net_device *dev,
 					  netdev_features_t features)
 {
 	struct hsr_priv *hsr = netdev_priv(dev);

 	return hsr_features_recompute(hsr, features);
 }


 static int hsr_dev_xmit(struct sk_buff *skb, struct net_device *dev)
 {
 	struct hsr_priv *hsr = netdev_priv(dev);
 	struct hsr_port *master;

 	master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
 	skb->dev = master->dev;
 	hsr_forward_skb(skb, master);

 	return NETDEV_TX_OK;
 }


 static const struct header_ops hsr_header_ops = {
 	.create	 = eth_header,
 	.parse	 = eth_header_parse,
 };

 static void send_hsr_supervision_frame(struct hsr_port *master,
 		u8 type, u8 hsrVer)
 {
 	struct sk_buff *skb;
 	int hlen, tlen;
 	struct hsr_tag *hsr_tag;
 	struct hsr_sup_tag *hsr_stag;
 	struct hsr_sup_payload *hsr_sp;
 	unsigned long irqflags;

 	hlen = LL_RESERVED_SPACE(master->dev);
 	tlen = master->dev->needed_tailroom;
 	skb = dev_alloc_skb(
 			sizeof(struct hsr_tag) +
 			sizeof(struct hsr_sup_tag) +
 			sizeof(struct hsr_sup_payload) + hlen + tlen);

 	if (skb == NULL)
 		return;

 	skb_reserve(skb, hlen);

 	skb->dev = master->dev;
 	skb->protocol = htons(hsrVer ? ETH_P_HSR : ETH_P_PRP);
 	skb->priority = TC_PRIO_CONTROL;

 	if (dev_hard_header(skb, skb->dev, (hsrVer ? ETH_P_HSR : ETH_P_PRP),
 			    master->hsr->sup_multicast_addr,
 			    skb->dev->dev_addr, skb->len) <= 0)
 		goto out;
 	skb_reset_mac_header(skb);

 	if (hsrVer > 0) {
 		hsr_tag = skb_put(skb, sizeof(struct hsr_tag));
 		hsr_tag->encap_proto = htons(ETH_P_PRP);
 		set_hsr_tag_LSDU_size(hsr_tag, HSR_V1_SUP_LSDUSIZE);
 	}

 	hsr_stag = skb_put(skb, sizeof(struct hsr_sup_tag));
 	set_hsr_stag_path(hsr_stag, (hsrVer ? 0x0 : 0xf));
 	set_hsr_stag_HSR_Ver(hsr_stag, hsrVer);

 	/* From HSRv1 on we have separate supervision sequence numbers. */
 	spin_lock_irqsave(&master->hsr->seqnr_lock, irqflags);
 	if (hsrVer > 0) {
 		hsr_stag->sequence_nr = htons(master->hsr->sup_sequence_nr);
 		hsr_tag->sequence_nr = htons(master->hsr->sequence_nr);
 		master->hsr->sup_sequence_nr++;
 		master->hsr->sequence_nr++;
 	} else {
 		hsr_stag->sequence_nr = htons(master->hsr->sequence_nr);
 		master->hsr->sequence_nr++;
 	}
 	spin_unlock_irqrestore(&master->hsr->seqnr_lock, irqflags);

 	hsr_stag->HSR_TLV_Type = type;
 	/* TODO: Why 12 in HSRv0? */
 	hsr_stag->HSR_TLV_Length = hsrVer ? sizeof(struct hsr_sup_payload) : 12;

 	/* Payload: MacAddressA */
 	hsr_sp = skb_put(skb, sizeof(struct hsr_sup_payload));
 	ether_addr_copy(hsr_sp->MacAddressA, master->dev->dev_addr);

 	skb_put_padto(skb, ETH_ZLEN + HSR_HLEN);

 	hsr_forward_skb(skb, master);
 	return;

 out:
 	WARN_ONCE(1, "HSR: Could not send supervision frame\n");
 	kfree_skb(skb);
 }


 /* Announce (supervision frame) timer function
  */
 static void hsr_announce(unsigned long data)
 {
 	struct hsr_priv *hsr;
 	struct hsr_port *master;

 	hsr = (struct hsr_priv *) data;

 	rcu_read_lock();
 	master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);

 	if (hsr->announce_count < 3 && hsr->protVersion == 0) {
 		send_hsr_supervision_frame(master, HSR_TLV_ANNOUNCE,
 				hsr->protVersion);
 		hsr->announce_count++;

 		hsr->announce_timer.expires = jiffies +
 				msecs_to_jiffies(HSR_ANNOUNCE_INTERVAL);
 	} else {
 		send_hsr_supervision_frame(master, HSR_TLV_LIFE_CHECK,
 				hsr->protVersion);

 		hsr->announce_timer.expires = jiffies +
 				msecs_to_jiffies(HSR_LIFE_CHECK_INTERVAL);
 	}

 	if (is_admin_up(master->dev))
 		add_timer(&hsr->announce_timer);

 	rcu_read_unlock();
 }


 /* According to comments in the declaration of struct net_device, this function
  * is "Called from unregister, can be used to call free_netdev". Ok then...
  */
 static void hsr_dev_destroy(struct net_device *hsr_dev)
 {
 	struct hsr_priv *hsr;
 	struct hsr_port *port;

 	hsr = netdev_priv(hsr_dev);

 	rtnl_lock();
 	hsr_for_each_port(hsr, port)
 		hsr_del_port(port);
 	rtnl_unlock();

 	del_timer_sync(&hsr->prune_timer);
 	del_timer_sync(&hsr->announce_timer);

 	synchronize_rcu();
 }

 static const struct net_device_ops hsr_device_ops = {
 	.ndo_change_mtu = hsr_dev_change_mtu,
 	.ndo_open = hsr_dev_open,
 	.ndo_stop = hsr_dev_close,
 	.ndo_start_xmit = hsr_dev_xmit,
 	.ndo_fix_features = hsr_fix_features,
 };

 static struct device_type hsr_type = {
 	.name = "hsr",
 };

 void hsr_dev_setup(struct net_device *dev)
 {
 	eth_hw_addr_random(dev);

 	ether_setup(dev);
 	dev->min_mtu = 0;
 	dev->header_ops = &hsr_header_ops;
 	dev->netdev_ops = &hsr_device_ops;
 	SET_NETDEV_DEVTYPE(dev, &hsr_type);
 	dev->priv_flags |= IFF_NO_QUEUE;

 	dev->needs_free_netdev = true;
 	dev->priv_destructor = hsr_dev_destroy;

 	dev->hw_features = NETIF_F_SG | NETIF_F_FRAGLIST | NETIF_F_HIGHDMA |
 			   NETIF_F_GSO_MASK | NETIF_F_HW_CSUM |
 			   NETIF_F_HW_VLAN_CTAG_TX;

 	dev->features = dev->hw_features;

 	/* Prevent recursive tx locking */
 	dev->features |= NETIF_F_LLTX;
 	/* VLAN on top of HSR needs testing and probably some work on
 	 * hsr_header_create() etc.
 	 */
 	dev->features |= NETIF_F_VLAN_CHALLENGED;
 	/* Not sure about this. Taken from bridge code. netdev_features.h says
 	 * it means "Does not change network namespaces".
 	 */
 	dev->features |= NETIF_F_NETNS_LOCAL;
 }


 /* Return true if dev is a HSR master; return false otherwise.
  */
 inline bool is_hsr_master(struct net_device *dev)
 {
 	return (dev->netdev_ops->ndo_start_xmit == hsr_dev_xmit);
 }

 /* Default multicast address for HSR Supervision frames */
 static const unsigned char def_multicast_addr[ETH_ALEN] __aligned(2) = {
 	0x01, 0x15, 0x4e, 0x00, 0x01, 0x00
 };

 int hsr_dev_finalize(struct net_device *hsr_dev, struct net_device *slave[2],
 		     unsigned char multicast_spec, u8 protocol_version)
 {
 	struct hsr_priv *hsr;
 	struct hsr_port *port;
 	int res;

 	hsr = netdev_priv(hsr_dev);
 	INIT_LIST_HEAD(&hsr->ports);
 	INIT_LIST_HEAD(&hsr->node_db);
 	INIT_LIST_HEAD(&hsr->self_node_db);

 	ether_addr_copy(hsr_dev->dev_addr, slave[0]->dev_addr);

 	/* Make sure we recognize frames from ourselves in hsr_rcv() */
 	res = hsr_create_self_node(&hsr->self_node_db, hsr_dev->dev_addr,
 				   slave[1]->dev_addr);
 	if (res < 0)
 		return res;

 	spin_lock_init(&hsr->seqnr_lock);
 	/* Overflow soon to find bugs easier: */
 	hsr->sequence_nr = HSR_SEQNR_START;
 	hsr->sup_sequence_nr = HSR_SUP_SEQNR_START;

 	setup_timer(&hsr->announce_timer, hsr_announce, (unsigned long)hsr);

 	setup_timer(&hsr->prune_timer, hsr_prune_nodes, (unsigned long)hsr);

 	ether_addr_copy(hsr->sup_multicast_addr, def_multicast_addr);
 	hsr->sup_multicast_addr[ETH_ALEN - 1] = multicast_spec;

 	hsr->protVersion = protocol_version;

 	/* FIXME: should I modify the value of these?
 	 *
 	 * - hsr_dev->flags - i.e.
 	 *			IFF_MASTER/SLAVE?
 	 * - hsr_dev->priv_flags - i.e.
 	 *			IFF_EBRIDGE?
 	 *			IFF_TX_SKB_SHARING?
 	 *			IFF_HSR_MASTER/SLAVE?
 	 */

 	/* Make sure the 1st call to netif_carrier_on() gets through */
 	netif_carrier_off(hsr_dev);

 	res = hsr_add_port(hsr, hsr_dev, HSR_PT_MASTER);
 	if (res)
 		return res;

 	res = register_netdevice(hsr_dev);
 	if (res)
 		goto fail;

 	res = hsr_add_port(hsr, slave[0], HSR_PT_SLAVE_A);
 	if (res)
 		goto fail;
 	res = hsr_add_port(hsr, slave[1], HSR_PT_SLAVE_B);
 	if (res)
 		goto fail;

 	mod_timer(&hsr->prune_timer, jiffies + msecs_to_jiffies(PRUNE_PERIOD));

 	return 0;

 fail:
 	hsr_for_each_port(hsr, port)
 		hsr_del_port(port);

 	return res;
 }
	/* Copyright 2011-2014 Autronica Fire and Security AS
	*
	* This program is free software; you can redistribute it and/or modify it
	* under the terms of the GNU General Public License as published by the Free
	* Software Foundation; either version 2 of the License, or (at your option)
	* any later version.
	*
	* Author(s):
	* 2011-2014 Arvid Brodin, arvid.brodin@alten.se
	*
	* This file contains device methods for creating, using and destroying
	* virtual HSR devices.
	*/

	#include <linux/netdevice.h>
	#include <linux/skbuff.h>
	#include <linux/etherdevice.h>
	#include <linux/rtnetlink.h>
	#include <linux/pkt_sched.h>
	#include "hsr_device.h"
	#include "hsr_slave.h"
	#include "hsr_framereg.h"
	#include "hsr_main.h"
	#include "hsr_forward.h"


	static bool is_admin_up(struct net_device *dev)
	{
	return dev && (dev->flags & IFF_UP);
	}

	static bool is_slave_up(struct net_device *dev)
	{
	return dev && is_admin_up(dev) && netif_oper_up(dev);
	}

	static void __hsr_set_operstate(struct net_device *dev, int transition)
	{
	write_lock_bh(&dev_base_lock);
	if (dev->operstate != transition) {
	dev->operstate = transition;
	write_unlock_bh(&dev_base_lock);
	netdev_state_change(dev);
	} else {
	write_unlock_bh(&dev_base_lock);
	}
	}

	static void hsr_set_operstate(struct hsr_port *master, bool has_carrier)
	{
	if (!is_admin_up(master->dev)) {
	__hsr_set_operstate(master->dev, IF_OPER_DOWN);
	return;
	}

	if (has_carrier)
	__hsr_set_operstate(master->dev, IF_OPER_UP);
	else
	__hsr_set_operstate(master->dev, IF_OPER_LOWERLAYERDOWN);
	}

	static bool hsr_check_carrier(struct hsr_port *master)
	{
	struct hsr_port *port;
	bool has_carrier;

	has_carrier = false;

	rcu_read_lock();
	hsr_for_each_port(master->hsr, port)
	if ((port->type != HSR_PT_MASTER) && is_slave_up(port->dev)) {
	has_carrier = true;
	break;
	}
	rcu_read_unlock();

	if (has_carrier)
	netif_carrier_on(master->dev);
	else
	netif_carrier_off(master->dev);

	return has_carrier;
	}


	static void hsr_check_announce(struct net_device *hsr_dev,
	unsigned char old_operstate)
	{
	struct hsr_priv *hsr;

	hsr = netdev_priv(hsr_dev);

	if ((hsr_dev->operstate == IF_OPER_UP)
	&& (old_operstate != IF_OPER_UP)) {
	/* Went up */
	hsr->announce_count = 0;
	hsr->announce_timer.expires = jiffies +
	msecs_to_jiffies(HSR_ANNOUNCE_INTERVAL);
	add_timer(&hsr->announce_timer);
	}

	if ((hsr_dev->operstate != IF_OPER_UP) && (old_operstate == IF_OPER_UP))
	/* Went down */
	del_timer(&hsr->announce_timer);
	}

	void hsr_check_carrier_and_operstate(struct hsr_priv *hsr)
	{
	struct hsr_port *master;
	unsigned char old_operstate;
	bool has_carrier;

	master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
	/* netif_stacked_transfer_operstate() cannot be used here since
	* it doesn't set IF_OPER_LOWERLAYERDOWN (?)
	*/
	old_operstate = master->dev->operstate;
	has_carrier = hsr_check_carrier(master);
	hsr_set_operstate(master, has_carrier);
	hsr_check_announce(master->dev, old_operstate);
	}

	int hsr_get_max_mtu(struct hsr_priv *hsr)
	{
	unsigned int mtu_max;
	struct hsr_port *port;

	mtu_max = ETH_DATA_LEN;
	rcu_read_lock();
	hsr_for_each_port(hsr, port)
	if (port->type != HSR_PT_MASTER)
	mtu_max = min(port->dev->mtu, mtu_max);
	rcu_read_unlock();

	if (mtu_max < HSR_HLEN)
	return 0;
	return mtu_max - HSR_HLEN;
	}


	static int hsr_dev_change_mtu(struct net_device *dev, int new_mtu)
	{
	struct hsr_priv *hsr;
	struct hsr_port *master;

	hsr = netdev_priv(dev);
	master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);

	if (new_mtu > hsr_get_max_mtu(hsr)) {
	netdev_info(master->dev, "A HSR master's MTU cannot be greater than the smallest MTU of its slaves minus the HSR Tag length (%d octets).\n",
	HSR_HLEN);
	return -EINVAL;
	}

	dev->mtu = new_mtu;

	return 0;
	}

	static int hsr_dev_open(struct net_device *dev)
	{
	struct hsr_priv *hsr;
	struct hsr_port *port;
	char designation;

	hsr = netdev_priv(dev);
	designation = '\0';

	rcu_read_lock();
	hsr_for_each_port(hsr, port) {
	if (port->type == HSR_PT_MASTER)
	continue;
	switch (port->type) {
	case HSR_PT_SLAVE_A:
	designation = 'A';
	break;
	case HSR_PT_SLAVE_B:
	designation = 'B';
	break;
	default:
	designation = '?';
	}
	if (!is_slave_up(port->dev))
	netdev_warn(dev, "Slave %c (%s) is not up; please bring it up to get a fully working HSR network\n",
	designation, port->dev->name);
	}
	rcu_read_unlock();

	if (designation == '\0')
	netdev_warn(dev, "No slave devices configured\n");

	return 0;
	}


	static int hsr_dev_close(struct net_device *dev)
	{
	/* Nothing to do here. */
	return 0;
	}


	static netdev_features_t hsr_features_recompute(struct hsr_priv *hsr,
	netdev_features_t features)
	{
	netdev_features_t mask;
	struct hsr_port *port;

	mask = features;

	/* Mask out all features that, if supported by one device, should be
	* enabled for all devices (see NETIF_F_ONE_FOR_ALL).
	*
	* Anything that's off in mask will not be enabled - so only things
	* that were in features originally, and also is in NETIF_F_ONE_FOR_ALL,
	* may become enabled.
	*/
	features &= ~NETIF_F_ONE_FOR_ALL;
	hsr_for_each_port(hsr, port)
	features = netdev_increment_features(features,
	port->dev->features,
	mask);

	return features;
	}

	static netdev_features_t hsr_fix_features(struct net_device *dev,
	netdev_features_t features)
	{
	struct hsr_priv *hsr = netdev_priv(dev);

	return hsr_features_recompute(hsr, features);
	}


	static int hsr_dev_xmit(struct sk_buff skb, struct net_device dev)
	{
	struct hsr_priv *hsr = netdev_priv(dev);
	struct hsr_port *master;

	master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);
	skb->dev = master->dev;
	hsr_forward_skb(skb, master);

	return NETDEV_TX_OK;
	}


	static const struct header_ops hsr_header_ops = {
	.create = eth_header,
	.parse = eth_header_parse,
	};

	static void send_hsr_supervision_frame(struct hsr_port *master,
	u8 type, u8 hsrVer)
	{
	struct sk_buff *skb;
	int hlen, tlen;
	struct hsr_tag *hsr_tag;
	struct hsr_sup_tag *hsr_stag;
	struct hsr_sup_payload *hsr_sp;
	unsigned long irqflags;

	hlen = LL_RESERVED_SPACE(master->dev);
	tlen = master->dev->needed_tailroom;
	skb = dev_alloc_skb(
	sizeof(struct hsr_tag) +
	sizeof(struct hsr_sup_tag) +
	sizeof(struct hsr_sup_payload) + hlen + tlen);

	if (skb == NULL)
	return;

	skb_reserve(skb, hlen);

	skb->dev = master->dev;
	skb->protocol = htons(hsrVer ? ETH_P_HSR : ETH_P_PRP);
	skb->priority = TC_PRIO_CONTROL;

	if (dev_hard_header(skb, skb->dev, (hsrVer ? ETH_P_HSR : ETH_P_PRP),
	master->hsr->sup_multicast_addr,
	skb->dev->dev_addr, skb->len) <= 0)
	goto out;
	skb_reset_mac_header(skb);

	if (hsrVer > 0) {
	hsr_tag = skb_put(skb, sizeof(struct hsr_tag));
	hsr_tag->encap_proto = htons(ETH_P_PRP);
	set_hsr_tag_LSDU_size(hsr_tag, HSR_V1_SUP_LSDUSIZE);
	}

	hsr_stag = skb_put(skb, sizeof(struct hsr_sup_tag));
	set_hsr_stag_path(hsr_stag, (hsrVer ? 0x0 : 0xf));
	set_hsr_stag_HSR_Ver(hsr_stag, hsrVer);

	/* From HSRv1 on we have separate supervision sequence numbers. */
	spin_lock_irqsave(&master->hsr->seqnr_lock, irqflags);
	if (hsrVer > 0) {
	hsr_stag->sequence_nr = htons(master->hsr->sup_sequence_nr);
	hsr_tag->sequence_nr = htons(master->hsr->sequence_nr);
	master->hsr->sup_sequence_nr++;
	master->hsr->sequence_nr++;
	} else {
	hsr_stag->sequence_nr = htons(master->hsr->sequence_nr);
	master->hsr->sequence_nr++;
	}
	spin_unlock_irqrestore(&master->hsr->seqnr_lock, irqflags);

	hsr_stag->HSR_TLV_Type = type;
	/* TODO: Why 12 in HSRv0? */
	hsr_stag->HSR_TLV_Length = hsrVer ? sizeof(struct hsr_sup_payload) : 12;

	/* Payload: MacAddressA */
	hsr_sp = skb_put(skb, sizeof(struct hsr_sup_payload));
	ether_addr_copy(hsr_sp->MacAddressA, master->dev->dev_addr);

	skb_put_padto(skb, ETH_ZLEN + HSR_HLEN);

	hsr_forward_skb(skb, master);
	return;

	out:
	WARN_ONCE(1, "HSR: Could not send supervision frame\n");
	kfree_skb(skb);
	}


	/* Announce (supervision frame) timer function
	*/
	static void hsr_announce(unsigned long data)
	{
	struct hsr_priv *hsr;
	struct hsr_port *master;

	hsr = (struct hsr_priv *) data;

	rcu_read_lock();
	master = hsr_port_get_hsr(hsr, HSR_PT_MASTER);

	if (hsr->announce_count < 3 && hsr->protVersion == 0) {
	send_hsr_supervision_frame(master, HSR_TLV_ANNOUNCE,
	hsr->protVersion);
	hsr->announce_count++;

	hsr->announce_timer.expires = jiffies +
	msecs_to_jiffies(HSR_ANNOUNCE_INTERVAL);
	} else {
	send_hsr_supervision_frame(master, HSR_TLV_LIFE_CHECK,
	hsr->protVersion);

	hsr->announce_timer.expires = jiffies +
	msecs_to_jiffies(HSR_LIFE_CHECK_INTERVAL);
	}

	if (is_admin_up(master->dev))
	add_timer(&hsr->announce_timer);

	rcu_read_unlock();
	}


	/* According to comments in the declaration of struct net_device, this function
	* is "Called from unregister, can be used to call free_netdev". Ok then...
	*/
	static void hsr_dev_destroy(struct net_device *hsr_dev)
	{
	struct hsr_priv *hsr;
	struct hsr_port *port;

	hsr = netdev_priv(hsr_dev);

	rtnl_lock();
	hsr_for_each_port(hsr, port)
	hsr_del_port(port);
	rtnl_unlock();

	del_timer_sync(&hsr->prune_timer);
	del_timer_sync(&hsr->announce_timer);

	synchronize_rcu();
	}

	static const struct net_device_ops hsr_device_ops = {
	.ndo_change_mtu = hsr_dev_change_mtu,
	.ndo_open = hsr_dev_open,
	.ndo_stop = hsr_dev_close,
	.ndo_start_xmit = hsr_dev_xmit,
	.ndo_fix_features = hsr_fix_features,
	};

	static struct device_type hsr_type = {
	.name = "hsr",
	};

	void hsr_dev_setup(struct net_device *dev)
	{
	eth_hw_addr_random(dev);

	ether_setup(dev);
	dev->min_mtu = 0;
	dev->header_ops = &hsr_header_ops;
	dev->netdev_ops = &hsr_device_ops;
	SET_NETDEV_DEVTYPE(dev, &hsr_type);
	dev->priv_flags \|= IFF_NO_QUEUE;

	dev->needs_free_netdev = true;
	dev->priv_destructor = hsr_dev_destroy;

	dev->hw_features = NETIF_F_SG \| NETIF_F_FRAGLIST \| NETIF_F_HIGHDMA \|
	NETIF_F_GSO_MASK \| NETIF_F_HW_CSUM \|
	NETIF_F_HW_VLAN_CTAG_TX;

	dev->features = dev->hw_features;

	/* Prevent recursive tx locking */
	dev->features \|= NETIF_F_LLTX;
	/* VLAN on top of HSR needs testing and probably some work on
	* hsr_header_create() etc.
	*/
	dev->features \|= NETIF_F_VLAN_CHALLENGED;
	/* Not sure about this. Taken from bridge code. netdev_features.h says
	* it means "Does not change network namespaces".
	*/
	dev->features \|= NETIF_F_NETNS_LOCAL;
	}


	/* Return true if dev is a HSR master; return false otherwise.
	*/
	inline bool is_hsr_master(struct net_device *dev)
	{
	return (dev->netdev_ops->ndo_start_xmit == hsr_dev_xmit);
	}

	/* Default multicast address for HSR Supervision frames */
	static const unsigned char def_multicast_addr[ETH_ALEN] __aligned(2) = {
	0x01, 0x15, 0x4e, 0x00, 0x01, 0x00
	};

	int hsr_dev_finalize(struct net_device hsr_dev, struct net_device slave[2],
	unsigned char multicast_spec, u8 protocol_version)
	{
	struct hsr_priv *hsr;
	struct hsr_port *port;
	int res;

	hsr = netdev_priv(hsr_dev);
	INIT_LIST_HEAD(&hsr->ports);
	INIT_LIST_HEAD(&hsr->node_db);
	INIT_LIST_HEAD(&hsr->self_node_db);

	ether_addr_copy(hsr_dev->dev_addr, slave[0]->dev_addr);

	/* Make sure we recognize frames from ourselves in hsr_rcv() */
	res = hsr_create_self_node(&hsr->self_node_db, hsr_dev->dev_addr,
	slave[1]->dev_addr);
	if (res < 0)
	return res;

	spin_lock_init(&hsr->seqnr_lock);
	/* Overflow soon to find bugs easier: */
	hsr->sequence_nr = HSR_SEQNR_START;
	hsr->sup_sequence_nr = HSR_SUP_SEQNR_START;

	setup_timer(&hsr->announce_timer, hsr_announce, (unsigned long)hsr);

	setup_timer(&hsr->prune_timer, hsr_prune_nodes, (unsigned long)hsr);

	ether_addr_copy(hsr->sup_multicast_addr, def_multicast_addr);
	hsr->sup_multicast_addr[ETH_ALEN - 1] = multicast_spec;

	hsr->protVersion = protocol_version;

	/* FIXME: should I modify the value of these?
	*
	* - hsr_dev->flags - i.e.
	* IFF_MASTER/SLAVE?
	* - hsr_dev->priv_flags - i.e.
	* IFF_EBRIDGE?
	* IFF_TX_SKB_SHARING?
	* IFF_HSR_MASTER/SLAVE?
	*/

	/* Make sure the 1st call to netif_carrier_on() gets through */
	netif_carrier_off(hsr_dev);

	res = hsr_add_port(hsr, hsr_dev, HSR_PT_MASTER);
	if (res)
	return res;

	res = register_netdevice(hsr_dev);
	if (res)
	goto fail;

	res = hsr_add_port(hsr, slave[0], HSR_PT_SLAVE_A);
	if (res)
	goto fail;
	res = hsr_add_port(hsr, slave[1], HSR_PT_SLAVE_B);
	if (res)
	goto fail;

	mod_timer(&hsr->prune_timer, jiffies + msecs_to_jiffies(PRUNE_PERIOD));

	return 0;

	fail:
	hsr_for_each_port(hsr, port)
	hsr_del_port(port);

	return res;
	}