Subject: Re: [RFC v3 1/1] net/hsr: Add support for IEC 62439-3 High-availability Seamless Redundancy

From: Arvid Brodin <[email-masked]>
Date: Thu, 16 Aug 2012 19:17:49 +0000

diff --git a/Documentation/networking/hsr/hsr_genl.c b/Documentation/networking/hsr/hsr_genl.c
new file mode 100644
index 0000000..cb384d5
--- /dev/null
+++ b/Documentation/networking/hsr/hsr_genl.c
@@ -0,0 +1,221 @@
+/*
+ * Copyright 2011-2012 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):
+ *	2011-2012 Arvid Brodin, [email-masked]
+ *
+ * Userspace example of using Generic Netlink to get HSR
+ * ("High-availability Seamless Redundancy") link/network status.
+ *
+ * Needs userspace libnl-3. Current as of 2012-08-07.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <netlink/netlink.h>
+#include <netlink/socket.h>
+#include <netlink/attr.h>
+#include <netlink/genl/genl.h>
+#include <netlink/genl/ctrl.h>
+/**** insert path to hsr_netlink from your kernel below: ****/
+#include "<path>/net/hsr/hsr_netlink.h"
+
+
+static struct nla_policy hsr_genl_policy[HSR_A_MAX + 1] = {
+	[HSR_A_NODE_ADDR] = { .type = NLA_UNSPEC },
+	[HSR_A_IFINDEX] = { .type = NLA_U32 },
+	[HSR_A_IF1AGE] = { .type = NLA_U32 },
+	[HSR_A_IF2AGE] = { .type = NLA_U32 },
+};
+
+#define ETH_ALEN	6
+
+void print_mac(const unsigned char *addr)
+{
+	int i;
+
+	for (i = 0; i < ETH_ALEN; i++)
+		printf("%02x ", addr[i]);
+}
+
+
+int parse_genlmsg(struct nl_msg *msg, void *arg)
+{
+	struct nlattr *attrs[HSR_A_MAX + 1];
+	int rc;
+	struct genlmsghdr *hdr;
+	int i;
+
+	rc = genlmsg_parse(nlmsg_hdr(msg), 0, attrs, HSR_A_MAX, hsr_genl_policy);
+	if (rc < 0) {
+		printf("Error parsing genlmsg: %d\n", rc);
+		return rc;
+	}
+
+
+	/*
+	 * Extract command ID from "message" -> "netlink header" ->
+	 * "generic netlink header".
+	 *
+	 * These are the command enums used when creating a genl msg header
+	 * in the kernel with genlmsg_put().
+	 */
+	hdr = genlmsg_hdr(nlmsg_hdr(msg));
+
+	switch (hdr->cmd) {
+	case HSR_C_RING_ERROR:
+		printf("Ring error: \n");
+		break;
+	case HSR_C_NODE_DOWN:
+		printf("Node down: \n");
+		break;
+	case HSR_C_SET_NODE_STATUS:
+		printf("Node status: \n");
+		break;
+	default:
+		printf("Unknown genl message (%d)\n", hdr->cmd);
+	}
+
+
+	/*
+	 * Extract the attached data (the "attributes").
+	 */
+	for (i = 0; i < HSR_A_MAX + 1; i++)
+		if (attrs[i]) {
+			switch (attrs[i]->nla_type) {
+			case HSR_A_NODE_ADDR:
+				printf("    node address ");
+				print_mac(nla_data(attrs[i]));
+				printf("\n");
+				break;
+			case HSR_A_IFINDEX:
+				printf("    interface index %d\n",
+						nla_get_u32(attrs[i]));
+				break;
+			case HSR_A_IF1AGE:
+				printf("    last frame over slave #1 %d ms ago\n",
+						(int) nla_get_u32(attrs[i]));
+				break;
+			case HSR_A_IF2AGE:
+				printf("    last frame over slave #2 %d ms ago\n",
+						(int) nla_get_u32(attrs[i]));
+				break;
+			default:
+				printf("    unknown attribute type: %d\n",
+						attrs[i]->nla_type);
+			}
+		}
+
+	return 0;
+}
+
+/*
+ * Send a "simple" (header only) Generic Netlink message
+int query_link_status(int family)
+{
+	return (genl_send_simple(nlsk, family, HSR_C_GET_STATUS, 1, 0));
+}
+ */
+
+int query_node_status(struct nl_sock *nlsk, int family, int ifindex,
+		      const unsigned char node_addr[ETH_ALEN])
+{
+	struct nl_msg *msg;
+	void *user_hdr;
+
+	msg = nlmsg_alloc();
+	if (!msg)
+		return -1;
+
+	user_hdr = genlmsg_put(msg, NL_AUTO_PORT, NL_AUTO_SEQ, family,
+						0, 0, HSR_C_GET_NODE_STATUS, 1);
+	if (!user_hdr)
+		goto nla_put_failure;
+
+/*
+ * Query by interface name could be implemented in the kernel if needed:
+ *	NLA_PUT_STRING(msg, HSR_A_IFNAME, ifname);
+ */
+	NLA_PUT_U32(msg, HSR_A_IFINDEX, ifindex);
+	NLA_PUT(msg, HSR_A_NODE_ADDR, ETH_ALEN, node_addr);
+
+	printf("Querying if %d for status of node ", ifindex);
+	print_mac(node_addr);
+	printf("\n");
+
+	return nl_send_auto(nlsk, msg);
+
+nla_put_failure:
+	nlmsg_free(msg);
+	return -1;
+}
+
+
+int main()
+{
+	struct nl_sock *nlsk;
+	int hsr_mgroup;
+	int rc;
+
+	nlsk = nl_socket_alloc();
+	if (!nlsk) {
+		printf("nl_socket_alloc() failed\n");
+		return EXIT_FAILURE;
+	}
+	nl_socket_disable_seq_check(nlsk);
+	nl_socket_modify_cb(nlsk, NL_CB_VALID, NL_CB_CUSTOM, parse_genlmsg, NULL);
+	genl_connect(nlsk);
+
+	/*
+	 * Sign up for HSR messages
+	 */
+	hsr_mgroup = genl_ctrl_resolve_grp(nlsk, "HSR", "hsr-network");
+	if (hsr_mgroup < 0) {
+		printf("genl_ctrl_resolve_grp() failed: %d\n", hsr_mgroup);
+		rc = EXIT_FAILURE;
+		goto out;
+	}
+
+	printf("Registering for multicast group %d\n", hsr_mgroup);
+	rc = nl_socket_add_memberships(nlsk, hsr_mgroup, 0);
+	if (rc < 0) {
+		printf("nl_socket_add_memberships() failed: %d\n", rc);
+		goto out;
+	}
+
+	/*
+	 * Send a query about the status of another node on the HSR network:
+	 */
+	int hsr_family;
+	/* The hsr if we send the enquiry to (get it with e.g.
+	 * 'cat /sys/class/net/hsr0/ifindex'): */
+	const int hsr_ifindex = 4;
+	/* The node to enquire about: */
+	const unsigned char node[ETH_ALEN] = {0x00, 0x24, 0x74, 0x00, 0x17, 0xAD};
+
+	hsr_family = genl_ctrl_resolve(nlsk, "HSR");
+	if (hsr_family < 0) {
+		printf("genl_ctrl_resolve() failed: %d\n", hsr_family);
+		goto receive;
+	}
+	rc = query_node_status(nlsk, hsr_family, hsr_ifindex, node);
+	printf("query_node_status() returned %d\n", rc);
+
+	/*
+	 * Receive messages
+	 */
+receive:
+	while (1)
+		nl_recvmsgs_default(nlsk);
+
+	rc = EXIT_SUCCESS;
+out:
+	nl_close(nlsk);
+	nl_socket_free(nlsk);
+	return rc;
+}
diff --git a/include/linux/if_ether.h b/include/linux/if_ether.h
index 56d907a..0d0e2f9 100644
--- a/include/linux/if_ether.h
+++ b/include/linux/if_ether.h
@@ -83,6 +83,7 @@
 #define ETH_P_TIPC	0x88CA		/* TIPC 			*/
 #define ETH_P_8021AH	0x88E7          /* 802.1ah Backbone Service Tag */
 #define ETH_P_1588	0x88F7		/* IEEE 1588 Timesync */
+#define ETH_P_HSR	0x88FB		/* IEC 62439-3 HSR/PRP		*/
 #define ETH_P_FCOE	0x8906		/* Fibre Channel over Ethernet  */
 #define ETH_P_TDLS	0x890D          /* TDLS */
 #define ETH_P_FIP	0x8914		/* FCoE Initialization Protocol */
diff --git a/include/linux/if_link.h b/include/linux/if_link.h
index 4b24ff4..3e3efb4 100644
--- a/include/linux/if_link.h
+++ b/include/linux/if_link.h
@@ -391,4 +391,15 @@ struct ifla_port_vsi {
 	__u8 pad[3];
 };

+/* HSR section */
+
+enum {
+	IFLA_HSR_UNSPEC,
+	IFLA_HSR_SLAVE1,
+	IFLA_HSR_SLAVE2,
+	__IFLA_HSR_MAX,
+};
+
+#define IFLA_HSR_MAX (__IFLA_HSR_MAX - 1)
+
 #endif /* _LINUX_IF_LINK_H */
diff --git a/net/Kconfig b/net/Kconfig
index e07272d..22446d3 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -216,6 +216,7 @@ source "net/dcb/Kconfig"
 source "net/dns_resolver/Kconfig"
 source "net/batman-adv/Kconfig"
 source "net/openvswitch/Kconfig"
+source "net/hsr/Kconfig"

 config RPS
 	boolean
diff --git a/net/Makefile b/net/Makefile
index ad432fa..7d8787f 100644
--- a/net/Makefile
+++ b/net/Makefile
@@ -70,3 +70,4 @@ obj-$(CONFIG_CEPH_LIB)		+= ceph/
 obj-$(CONFIG_BATMAN_ADV)	+= batman-adv/
 obj-$(CONFIG_NFC)		+= nfc/
 obj-$(CONFIG_OPENVSWITCH)	+= openvswitch/
+obj-$(CONFIG_HSR)		+= hsr/
diff --git a/net/hsr/Kconfig b/net/hsr/Kconfig
new file mode 100644
index 0000000..a9ed304
--- /dev/null
+++ b/net/hsr/Kconfig
@@ -0,0 +1,33 @@
+#
+# IEC 62439-3 High-availability Seamless Redundancy
+#
+
+config HSR
+	tristate "High-availability Seamless Redundancy (HSR)"
+	---help---
+	  If you say Y here, then your Linux box will be able to act as a
+	  DANH ("Doubly attached node implementing HSR"). For this to work,
+	  your Linux box needs (at least) two physical Ethernet interfaces,
+	  and you need to enslave these to a virtual hsr interface using the
+	  appropriate user space tool, i.e.:
+
+	  # ip link add name hsr0 type hsr dev1 dev2
+
+	  Your Linux box must be connected as a node in a ring network
+	  together with other HSR capable nodes.
+
+	  All Ethernet frames sent over the hsr device will be sent in both
+	  directions on the ring (over both slave ports), giving a redundant,
+	  instant fail-over network.
+
+	  Each HSR node in the ring acts like a bridge for HSR frames, but
+	  filters frames that have been forwarded earlier.
+
+	  This code is a "best effort" to comply with the HSR standard as
+	  described in IEC 62439-3, but no compliancy tests have been made.
+	  You need to perform any and all necessary tests yourself before
+	  relying on this code in a safety critical system. In particular, the
+	  standard is very diffuse on how to use the Ring ID field in the HSR
+	  tag, and it's probable that this code does not do the right thing.
+
+	  If unsure, say N.
diff --git a/net/hsr/Makefile b/net/hsr/Makefile
new file mode 100644
index 0000000..b68359f
--- /dev/null
+++ b/net/hsr/Makefile
@@ -0,0 +1,7 @@
+#
+# Makefile for HSR
+#
+
+obj-$(CONFIG_HSR)	+= hsr.o
+
+hsr-y			:= hsr_main.o hsr_framereg.o hsr_device.o hsr_netlink.o
diff --git a/net/hsr/hsr_device.c b/net/hsr/hsr_device.c
new file mode 100644
index 0000000..cd42ff3
--- /dev/null
+++ b/net/hsr/hsr_device.c
@@ -0,0 +1,506 @@
+/*
+ * Copyright 2011-2012 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):
+ *	2011-2012 Arvid Brodin, [email-masked]
+ *
+ * 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/if_arp.h>
+#include <linux/rtnetlink.h>
+#include <linux/netfilter.h>
+#include <linux/netpoll.h>
+#include "hsr_framereg.h"
+#include "hsr_private.h"
+
+
+static bool is_admin_up(struct net_device *dev)
+{
+	return (dev->flags & IFF_UP);
+}
+
+static bool is_operstate_up(struct net_device *dev)
+{
+	return (dev->operstate == IF_OPER_UP);
+}
+
+static void __hsr_set_operstate(struct net_device *dev, int transition)
+{
+	if (dev->operstate != transition) {
+		write_lock_bh(&dev_base_lock);
+		dev->operstate = transition;
+		write_unlock_bh(&dev_base_lock);
+		netdev_state_change(dev);
+	}
+}
+
+void hsr_set_operstate(struct net_device *hsr_dev, struct net_device *slave1,
+		       struct net_device *slave2)
+{
+	if (!is_admin_up(hsr_dev)) {
+		__hsr_set_operstate(hsr_dev, IF_OPER_DOWN);
+		return;
+	}
+
+	if (is_operstate_up(slave1) || is_operstate_up(slave2))
+		__hsr_set_operstate(hsr_dev, IF_OPER_UP);
+	else
+		__hsr_set_operstate(hsr_dev, IF_OPER_LOWERLAYERDOWN);
+}
+
+void hsr_set_carrier(struct net_device *hsr_dev, struct net_device *slave1,
+		     struct net_device *slave2)
+{
+	if (is_operstate_up(slave1) || is_operstate_up(slave2))
+		netif_carrier_on(hsr_dev);
+	else
+		netif_carrier_off(hsr_dev);
+}
+
+
+void hsr_check_announce(struct net_device *hsr_dev, int old_operstate)
+{
+	struct hsr_priv *hsr_priv;
+
+	hsr_priv = netdev_priv(hsr_dev);
+
+	if ((hsr_dev->operstate == IF_OPER_UP) && (old_operstate != IF_OPER_UP)) {
+		/* Went up */
+		hsr_priv->announce_count = 0;
+		hsr_priv->announce_timer.expires = jiffies +
+				msecs_to_jiffies(HSR_ANNOUNCE_INTERVAL);
+		add_timer(&hsr_priv->announce_timer);
+	}
+
+	if ((hsr_dev->operstate != IF_OPER_UP) && (old_operstate == IF_OPER_UP))
+		/* Went down */
+		del_timer(&hsr_priv->announce_timer);
+}
+
+
+
+static int hsr_dev_open(struct net_device *dev)
+{
+	struct hsr_priv *hsr_priv;
+
+	hsr_priv = netdev_priv(dev);
+
+	dev_open(hsr_priv->slave_data[0].dev);
+	dev_open(hsr_priv->slave_data[1].dev);
+
+	return 0;
+}
+
+static int hsr_dev_close(struct net_device *dev)
+{
+	// FIXME: restore status of slaves?
+	return 0;
+}
+
+
+static void hsr_fill_tag(struct hsr_ethhdr *hsr_ethhdr, struct hsr_priv *hsr_priv)
+{
+	unsigned long irqflags;
+
+	/*
+	 * IEC 62439-1, p 48, says the 4-bit "path" field can take values
+	 * between 0001-1001 ("ring identifier", for regular HSR frames),
+	 * or 1111 ("HSR management", supervision frames). Unfortunately, the
+	 * spec writers forgot to explain what a "ring identifier" is, or
+	 * how it is used. So we just set this to 0001 for regular frames,
+	 * and 1111 for supervision frames.
+	 */
+	set_hsr_tag_path(&hsr_ethhdr->hsr_tag, 0x1);
+
+	/*
+	 * IEC 62439-1, p 12: "The link service data unit in an Ethernet frame
+	 * is the content of the frame located between the Length/Type field
+	 * and the Frame Check Sequence."
+	 *
+	 * IEC 62439-3, p 48, specifies the "original LPDU" to include the
+	 * original "LT" field (what "LT" means is not explained anywhere as
+	 * far as I can see - perhaps "Length/Type"?). So LSDU_size might
+	 * equal original length + 2.
+	 *   Also, the fact that this field is not used anywhere (might be used
+	 * by a RedBox connecting HSR and PRP nets?) means I cannot test its
+	 * correctness. Instead of guessing, I set this to 0 here, to make any
+	 * problems immediately apparent. Anyone using this driver with PRP/HSR
+	 * RedBoxes might need to fix this...
+	 */
+	set_hsr_tag_LSDU_size(&hsr_ethhdr->hsr_tag, 0);
+
+	spin_lock_irqsave(&hsr_priv->seqnr_lock, irqflags);
+	hsr_ethhdr->hsr_tag.sequence_nr = htons(hsr_priv->sequence_nr);
+	hsr_priv->sequence_nr++;
+	spin_unlock_irqrestore(&hsr_priv->seqnr_lock, irqflags);
+
+	hsr_ethhdr->hsr_tag.encap_proto = hsr_ethhdr->ethhdr.h_proto;
+
+	hsr_ethhdr->ethhdr.h_proto = htons(ETH_P_HSR);
+}
+
+static int slave_xmit(struct sk_buff *skb, struct net_device *dev,
+		      struct net_device *hsr_dev)
+{
+	skb_set_dev(skb, dev);
+	skb->priority = 1; // FIXME: what does this mean?
+
+	// FIXME: what's netpoll_tx_running?
+	if (netpoll_tx_running(hsr_dev))
+		return skb->dev->netdev_ops->ndo_start_xmit(skb, skb->dev);
+
+	return dev_queue_xmit(skb);
+}
+
+
+static int hsr_dev_xmit(struct sk_buff *skb, struct net_device *dev)
+{
+	struct hsr_priv *hsr_priv;
+	struct hsr_ethhdr *hsr_ethhdr;
+	struct sk_buff *skb2;
+	int res1, res2;
+
+	hsr_priv = netdev_priv(dev);
+	hsr_ethhdr = (struct hsr_ethhdr *) skb->data;
+
+	if ((ntohs(skb->protocol) != ETH_P_HSR) ||
+			(ntohs(hsr_ethhdr->ethhdr.h_proto) != ETH_P_HSR)) {
+
+		hsr_fill_tag(hsr_ethhdr, hsr_priv);
+		skb->protocol = htons(ETH_P_HSR);
+	}
+
+	skb2 = skb_clone(skb, GFP_ATOMIC);
+
+	res1 = slave_xmit(skb, hsr_priv->slave_data[0].dev, dev);
+	res2 = NET_XMIT_DROP;
+	if (skb2) {
+		/* Address substitution (IEC62439-3 pp 26, 50): replace mac
+		 * address of outgoing frame with that of the outgoing slave's.
+		 */
+		memcpy(hsr_ethhdr->ethhdr.h_source,
+					hsr_priv->slave_data[1].dev->dev_addr,
+					ETH_ALEN);
+		res2 = slave_xmit(skb2, hsr_priv->slave_data[1].dev, dev);
+	}
+
+	if (likely(res1 == NET_XMIT_SUCCESS || res1 == NET_XMIT_CN ||
+			res2 == NET_XMIT_SUCCESS || res2 == NET_XMIT_CN)) {
+		hsr_priv->dev->stats.tx_packets++;
+		hsr_priv->dev->stats.tx_bytes += skb->len;
+	} else
+		hsr_priv->dev->stats.tx_dropped++;
+
+	return NETDEV_TX_OK;
+}
+
+
+static int hsr_header_create(struct sk_buff *skb, struct net_device *dev,
+			     unsigned short type, const void *daddr,
+			     const void *saddr, unsigned int len)
+{
+	int res;
+
+	/* Make room for the HSR tag now. We will fill it in later (in
+	   hsr_dev_xmit) */
+	if (skb_headroom(skb) < HSR_TAGLEN + ETH_HLEN)
+		return -ENOBUFS;
+	skb_push(skb, HSR_TAGLEN);
+	res = eth_header(skb, dev, type, daddr, saddr, len + HSR_TAGLEN);
+	if (res <= 0)
+		return res;
+	skb_reset_mac_header(skb);
+
+	return res + HSR_TAGLEN;
+}
+
+
+static const struct header_ops hsr_header_ops = {
+	.create	 = hsr_header_create,
+	.parse	 = eth_header_parse,
+};
+
+
+static void send_hsr_supervision_frame(struct net_device *hsr_dev, u8 type)
+{
+	struct hsr_priv *hsr_priv;
+	struct sk_buff *skb;
+	struct hsr_sup_tag *hsr_stag;
+	struct hsr_sup_payload *hsr_sp;
+	unsigned long irqflags;
+
+	skb = alloc_skb(LL_ALLOCATED_SPACE(hsr_dev) +
+				sizeof(struct hsr_sup_payload),
+				GFP_ATOMIC);
+	if (skb == NULL)
+		return;
+
+	hsr_priv = netdev_priv(hsr_dev);
+
+	skb_reserve(skb, LL_RESERVED_SPACE(hsr_dev));
+
+	skb->dev = hsr_dev;
+	skb->protocol = htons(ETH_P_HSR);
+
+	if (dev_hard_header(skb, skb->dev, ETH_P_HSR, hsr_multicast_addr,
+					skb->dev->dev_addr, skb->len) < 0)
+		goto out;
+
+	skb_pull(skb, sizeof(struct ethhdr));
+	hsr_stag = (struct hsr_sup_tag *) skb->data;
+
+	set_hsr_stag_path(hsr_stag, 0xf);
+	set_hsr_stag_HSR_Ver(hsr_stag, 0);
+
+	spin_lock_irqsave(&hsr_priv->seqnr_lock, irqflags);
+	hsr_stag->sequence_nr = htons(hsr_priv->sequence_nr);
+	hsr_priv->sequence_nr++;
+	spin_unlock_irqrestore(&hsr_priv->seqnr_lock, irqflags);
+
+	hsr_stag->HSR_TLV_Type = type;
+	hsr_stag->HSR_TLV_Length = 12;
+
+	skb_push(skb, sizeof(struct ethhdr));
+
+	/* Payload: MacAddressA */
+	hsr_sp = (struct hsr_sup_payload *) skb_put(skb,
+				sizeof(struct hsr_sup_payload));
+	memcpy(hsr_sp->MacAddressA, hsr_dev->dev_addr, ETH_ALEN);
+
+	dev_queue_xmit(skb);
+	return;
+
+out:
+	kfree_skb(skb);
+}
+
+
+/*
+ * Announce (supervision frame) timer function
+ */
+static void hsr_announce(unsigned long data)
+{
+	struct hsr_priv *hsr_priv;
+
+	hsr_priv = (struct hsr_priv *) data;
+
+	if (hsr_priv->announce_count < 3) {
+		send_hsr_supervision_frame(hsr_priv->dev, HSR_TLV_ANNOUNCE);
+		hsr_priv->announce_count++;
+	} else
+		send_hsr_supervision_frame(hsr_priv->dev, HSR_TLV_LIFE_CHECK);
+
+	if (hsr_priv->announce_count < 3)
+		hsr_priv->announce_timer.expires = jiffies +
+				msecs_to_jiffies(HSR_ANNOUNCE_INTERVAL);
+	else
+		hsr_priv->announce_timer.expires = jiffies +
+				msecs_to_jiffies(HSR_LIFE_CHECK_INTERVAL);
+
+	if (is_admin_up(hsr_priv->dev))
+		add_timer(&hsr_priv->announce_timer);
+}
+
+
+
+
+static void restore_slaves(struct net_device *hsr_dev)
+{
+	struct hsr_priv *hsr_priv;
+	struct net_device *slave[2];
+	int i;
+	int res;
+
+	hsr_priv = netdev_priv(hsr_dev);
+	for (i = 0; i < 2; i++)
+		slave[i] = hsr_priv->slave_data[i].dev;
+
+	rtnl_lock();
+
+	/* Restore promiscuity */
+	for (i = 0; i < 2; i++) {
+		if (!hsr_priv->slave_data[i].promisc)
+			continue;
+		res = dev_set_promiscuity(slave[i],
+					-hsr_priv->slave_data[i].promisc);
+		if (res)
+			netdev_info(hsr_dev, "HSR: Cannot restore slave "
+						"promiscuity (%s, %d)\n",
+						slave[i]->name, res);
+	}
+
+	rtnl_unlock();
+}
+
+static void reclaim_hsr_dev(struct rcu_head *rh)
+{
+	struct hsr_priv *hsr_priv;
+
+	hsr_priv = container_of(rh, struct hsr_priv, rcu_head);
+	free_netdev(hsr_priv->dev);
+}
+
+/*
+ * 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_priv;
+
+	hsr_priv = netdev_priv(hsr_dev);
+
+	del_timer(&hsr_priv->announce_timer);
+	unregister_hsr_master(hsr_priv);    /* calls list_del_rcu on hsr_priv */
+	restore_slaves(hsr_dev);
+	call_rcu(&hsr_priv->rcu_head, reclaim_hsr_dev);   /* reclaim hsr_priv */
+}
+
+static const struct net_device_ops hsr_device_ops = {
+	.ndo_open = hsr_dev_open,
+	.ndo_stop = hsr_dev_close,
+	.ndo_start_xmit = hsr_dev_xmit,
+};
+
+
+void hsr_dev_setup(struct net_device *dev)
+{
+	random_ether_addr(dev->dev_addr);
+
+	ether_setup(dev);
+	dev->header_ops		 = &hsr_header_ops;
+	dev->netdev_ops		 = &hsr_device_ops;
+	dev->hard_header_len	+= HSR_TAGLEN;
+	dev->mtu		-= HSR_TAGLEN;
+	dev->tx_queue_len	 = 0;
+
+	dev->destructor = hsr_dev_destroy;
+}
+
+
+/*
+ * If dev is a HSR master, return 1; otherwise, return 0.
+ */
+bool is_hsr_master(struct net_device *dev)
+{
+	return (dev->netdev_ops->ndo_start_xmit == hsr_dev_xmit);
+}
+
+static int check_slave_ok(struct net_device *dev)
+{
+	/* Don't allow HSR on non-ethernet like devices */
+	if ((dev->flags & IFF_LOOPBACK) || (dev->type != ARPHRD_ETHER) ||
+						(dev->addr_len != ETH_ALEN)) {
+		netdev_info(dev, "Cannot enslave loopback or non-ethernet "
+								"device\n");
+		return -EINVAL;
+	}
+
+	/* Don't allow enslaving hsr devices */
+	if (is_hsr_master(dev)) {
+		netdev_info(dev, "Cannot create trees of hsr devices.\n");
+		return -ELOOP;
+	}
+
+	/* FIXME: What about VLAN devices, bonded devices, etc? */
+
+	return 0;
+}
+
+int hsr_dev_finalize(struct net_device *hsr_dev, struct net_device *slave[2])
+{
+	struct hsr_priv *hsr_priv;
+	int i;
+	int res;
+
+	hsr_priv = netdev_priv(hsr_dev);
+	hsr_priv->dev = hsr_dev;
+	INIT_LIST_HEAD(&hsr_priv->node_db);
+	INIT_LIST_HEAD(&hsr_priv->self_node_db);
+	for (i = 0; i < 2; i++)
+		hsr_priv->slave_data[i].dev = slave[i];
+
+	spin_lock_init(&hsr_priv->seqnr_lock);
+	hsr_priv->sequence_nr = 0;
+
+	init_timer(&hsr_priv->announce_timer);
+	hsr_priv->announce_timer.function = hsr_announce;
+	hsr_priv->announce_timer.data = (unsigned long) hsr_priv;
+
+
+/*
+ * FIXME: do I need to set the value of these?
+ *
+ * - hsr_dev->flags
+ * - hsr_dev->priv_flags
+ */
+
+	for (i = 0; i < 2; i++) {
+		res = check_slave_ok(slave[i]);
+		if (res)
+			return res;
+	}
+
+	hsr_dev->features = slave[0]->features & slave[1]->features;
+	hsr_dev->features |= NETIF_F_LLTX; /* Prevent recursive tx locking */
+
+	/* Save/init data needed for restore */
+	for (i = 0; i < 2; i++) {
+		hsr_priv->slave_data[i].was_up = slave[i]->flags & IFF_UP;
+		hsr_priv->slave_data[i].promisc = 0;
+	}
+
+	/* Set hsr_dev's MAC address to that of mac_slave1 */
+	memcpy(hsr_dev->dev_addr, hsr_priv->slave_data[0].dev->dev_addr,
+								ETH_ALEN);
+
+	/* MTU */
+	for (i = 0; i < 2; i++)
+		if (slave[i]->mtu < hsr_dev->mtu)
+			hsr_dev->mtu = slave[i]->mtu;
+
+	/* Make sure the 1st call to netif_carrier_on() gets through */
+	netif_carrier_off(hsr_dev);
+
+	/* Promiscuity */
+	for (i = 0; i < 2; i++) {
+		res = dev_set_promiscuity(slave[i], 1);
+		if (res) {
+			netdev_info(hsr_dev, "HSR: Cannot set slave "
+						"promiscuity (%s, %d)\n",
+						slave[i]->name, res);
+			goto fail;
+		}
+		/* Remember what we have done so we can restore it later */
+		hsr_priv->slave_data[i].promisc = 1;
+	}
+
+	/* Make sure we recognize frames from ourselves in hsr_rcv() */
+	res = hsr_create_self_node(&hsr_priv->self_node_db,
+					hsr_dev->dev_addr,
+					hsr_priv->slave_data[1].dev->dev_addr);
+	if (res < 0)
+		goto fail;
+
+	res = register_netdevice(hsr_dev);
+	if (res)
+		goto fail;
+
+	register_hsr_master(hsr_priv);
+
+	return 0;
+
+fail:
+	restore_slaves(hsr_dev);
+	return res;
+}
diff --git a/net/hsr/hsr_device.h b/net/hsr/hsr_device.h
new file mode 100644
index 0000000..9a1471b
--- /dev/null
+++ b/net/hsr/hsr_device.h
@@ -0,0 +1,27 @@
+/*
+ * Copyright 2011-2012 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):
+ *	2011-2012 Arvid Brodin, [email-masked]
+ */
+
+#ifndef __HSR_DEVICE_H
+#define __HSR_DEVICE_H
+
+#include <linux/netdevice.h>
+
+void hsr_dev_setup(struct net_device *dev);
+int hsr_dev_finalize(struct net_device *hsr_dev, struct net_device *slave[2]);
+void hsr_set_operstate(struct net_device *hsr_dev, struct net_device *slave1,
+		       struct net_device *slave2);
+void hsr_set_carrier(struct net_device *hsr_dev, struct net_device *slave1,
+		     struct net_device *slave2);
+void hsr_check_announce(struct net_device *hsr_dev, int old_operstate);
+bool is_hsr_master(struct net_device *dev);
+
+#endif /* __HSR_DEVICE_H */
diff --git a/net/hsr/hsr_framereg.c b/net/hsr/hsr_framereg.c
new file mode 100644
index 0000000..de406f6
--- /dev/null
+++ b/net/hsr/hsr_framereg.c
@@ -0,0 +1,303 @@
+/*
+ * Copyright 2011-2012 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):
+ *	2011-2012 Arvid Brodin, [email-masked]
+ *
+ * The HSR spec says never to forward the same frame twice on the same
+ * interface. A frame is identified by its source MAC address and its HSR
+ * sequence number. This code keeps track of senders and their sequence numbers
+ * to allow filtering of duplicate frames.
+ */
+
+#include <linux/if_ether.h>
+#include <linux/etherdevice.h>
+#include <linux/slab.h>
+#include <linux/rculist.h>
+#include "hsr_private.h"
+#include "hsr_framereg.h"
+#include "hsr_netlink.h"
+
+
+/*
+	TODO: use hash lists for mac addresses (linux/jhash.h)?
+*/
+
+struct node_entry {
+	struct list_head mac_list;
+	unsigned char	MacAddressA[ETH_ALEN];
+	unsigned char	MacAddressB[ETH_ALEN];
+	unsigned long	time_in[HSR_MAX_SLAVE];
+	u16		seq_out[HSR_MAX_DEV];
+	struct rcu_head rcu_head;
+};
+
+
+unsigned char *hsr_get_node_addr(struct node_entry *node)
+{
+	return node->MacAddressA;
+}
+
+
+/*
+ * Search for mac entry. Caller must hold rcu read lock.
+ */
+static struct node_entry *find_node_by_AddrA(struct list_head *node_db,
+					     unsigned char addr[ETH_ALEN])
+{
+	struct node_entry *node;
+
+	list_for_each_entry_rcu(node, node_db, mac_list)
+		if (!compare_ether_addr(node->MacAddressA, addr))
+			return node;
+
+	return NULL;
+}
+
+/*
+ * Search for mac entry. Caller must hold rcu read lock.
+ */
+static struct node_entry *find_node_by_AddrB(struct list_head *node_db,
+					     unsigned char addr[ETH_ALEN])
+{
+	struct node_entry *node;
+
+	list_for_each_entry_rcu(node, node_db, mac_list)
+		if (!compare_ether_addr(node->MacAddressB, addr))
+			return node;
+
+	return NULL;
+}
+
+/*
+ * Search for mac entry. Caller must hold rcu read lock.
+ */
+struct node_entry *hsr_find_node(struct list_head *node_db, struct sk_buff *skb)
+{
+	struct node_entry *node;
+	struct ethhdr *ethhdr;
+
+	if (!skb_mac_header_was_set(skb))
+		return NULL;
+
+	ethhdr = (struct ethhdr *) skb_mac_header(skb);
+
+	list_for_each_entry_rcu(node, node_db, mac_list) {
+		if (!compare_ether_addr(node->MacAddressA, ethhdr->h_source))
+			return node;
+		if (!compare_ether_addr(node->MacAddressB, ethhdr->h_source))
+			return node;
+	}
+
+	return NULL;
+}
+
+/*
+ * Helper for device init; the self_node_db is used in hsr_rcv() to recognize
+ * frames from self that's been looped over the HSR ring.
+ */
+int hsr_create_self_node(struct list_head *self_node_db,
+			 unsigned char addr_a[ETH_ALEN],
+			 unsigned char addr_b[ETH_ALEN])
+{
+	struct node_entry *node;
+
+	node = kmalloc(sizeof(*node), GFP_KERNEL);
+	if (!node)
+		return -ENOMEM;
+
+	memcpy(node->MacAddressA, addr_a, ETH_ALEN);
+	memcpy(node->MacAddressB, addr_b, ETH_ALEN);
+
+	list_add_tail_rcu(&node->mac_list, self_node_db);
+	return 0;
+}
+
+int hsr_merge_node(struct hsr_priv *hsr_priv, enum hsr_dev_idx dev_idx,
+		   struct sk_buff *skb)
+{
+	struct ethhdr *ethhdr;
+	struct hsr_sup_payload *hsr_sp;
+	struct node_entry *node;
+	int i;
+	int found;
+
+	ethhdr = (struct ethhdr *) skb_mac_header(skb);
+	hsr_sp = (struct hsr_sup_payload *) skb->data;
+
+	found = 1;
+	rcu_read_lock();
+	node = find_node_by_AddrA(&hsr_priv->node_db, hsr_sp->MacAddressA);
+	if (!node) {
+		rcu_read_unlock();
+		found = 0;
+		node = kmalloc(sizeof(*node), GFP_ATOMIC);
+		if (!node)
+			return -ENOMEM;
+
+		memcpy(node->MacAddressA, hsr_sp->MacAddressA, ETH_ALEN);
+		memcpy(node->MacAddressB, ethhdr->h_source, ETH_ALEN);
+
+		for (i = 0; i < HSR_MAX_SLAVE; i++)
+			node->time_in[i] = 0;
+		for (i = 0; i < HSR_MAX_DEV; i++)
+			node->seq_out[i] = 0;
+	}
+
+	/* Merge node if it's PICS_SUBS capable */
+	if (compare_ether_addr(hsr_sp->MacAddressA, ethhdr->h_source))
+		memcpy(node->MacAddressB, ethhdr->h_source, ETH_ALEN);
+
+	node->time_in[dev_idx] = jiffies;
+
+	if (found)
+		rcu_read_unlock();
+	else
+		list_add_tail_rcu(&node->mac_list, &hsr_priv->node_db);
+
+	return 0;
+}
+
+
+void hsr_addr_subst(struct hsr_priv *hsr_priv, struct sk_buff *skb)
+{
+	struct ethhdr *ethhdr;
+	struct node_entry *node;
+
+	ethhdr = (struct ethhdr *) skb_mac_header(skb);
+
+	rcu_read_lock();
+	node = find_node_by_AddrB(&hsr_priv->node_db, ethhdr->h_source);
+	if (node)
+		memcpy(ethhdr->h_source, node->MacAddressA, ETH_ALEN);
+	rcu_read_unlock();
+}
+
+
+
+/*
+ * above(a, b) - return 1 if a > b, 0 otherwise.
+ */
+static bool above(u16 a, u16 b)
+{
+	/* Remove inconsistency where above(a, b) == below(a, b) */
+	if ((int) b - a == 32768)
+		return 0;
+
+	return (((s16) (b - a)) < 0);
+}
+#define below(a, b)		above((b), (a))
+#define above_or_eq(a, b)	(!below((a), (b)))
+#define below_or_eq(a, b)	(!above((a), (b)))
+
+
+void hsr_register_frame_in(struct node_entry *node, enum hsr_dev_idx dev_idx)
+{
+	if ((dev_idx < 0) || (dev_idx >= HSR_MAX_DEV)) {
+		WARN_ON(1);
+		return;
+	}
+	node->time_in[dev_idx] = jiffies;
+}
+
+/*
+ * Parameters:
+ *	'skb' is a HSR Ethernet frame (with a HSR tag inserted), with a valid
+ *	ethhdr->h_source address and skb->mac_header set.
+ *
+ * Return:
+ *	 1 if frame can be shown to have been sent recently on this interface,
+ *	 0 otherwise, or
+ *	 negative error code on error
+ */
+int hsr_register_frame_out(struct node_entry *node, enum hsr_dev_idx dev_idx,
+			   struct sk_buff *skb)
+{
+	struct hsr_ethhdr *hsr_ethhdr;
+
+	if ((dev_idx < 0) || (dev_idx >= HSR_MAX_DEV)) {
+		WARN_ON(1);
+		return -EINVAL;
+	}
+	if (!skb_mac_header_was_set(skb)) {
+		WARN_ON(1);
+		return -EINVAL;
+	}
+	hsr_ethhdr = (struct hsr_ethhdr *) skb_mac_header(skb);
+
+	if (below_or_eq(hsr_ethhdr->hsr_tag.sequence_nr,
+							node->seq_out[dev_idx]))
+		return 1;
+
+	node->seq_out[dev_idx] = hsr_ethhdr->hsr_tag.sequence_nr;
+	return 0;
+}
+
+
+static void node_entry_reclaim(struct rcu_head *rh)
+{
+	kfree(container_of(rh, struct node_entry, rcu_head));
+}
+
+/*
+ * Remove stale sequence_nr records. Called by timer every
+ * HSR_LIFE_CHECK_INTERVAL (two seconds or so). This is also the only function
+ * that removes mac_entries; it shouldn't need to be rcu_read_lock():ed.
+ */
+void hsr_prune_nodes(struct list_head *node_db)
+{
+	struct node_entry *node_entry, *node_entry_next;
+	unsigned long timestamp;
+
+	list_for_each_entry_safe(node_entry, node_entry_next, node_db, mac_list) {
+
+		timestamp = max(node_entry->time_in[HSR_DEV_SLAVE1],
+				node_entry->time_in[HSR_DEV_SLAVE2]);
+
+		/* Warn only as long as we get frames at all */
+		if (time_is_after_jiffies(timestamp +
+					msecs_to_jiffies(1.5*MAX_SLAVE_DIFF))) {
+
+			/* Check for open ring */
+			if (time_after(node_entry->time_in[HSR_DEV_SLAVE2],
+					node_entry->time_in[HSR_DEV_SLAVE1] +
+					msecs_to_jiffies(MAX_SLAVE_DIFF)))
+				hsr_nl_ringerror(node_entry->MacAddressA, HSR_DEV_SLAVE1);
+			else if (time_after(node_entry->time_in[HSR_DEV_SLAVE1],
+					node_entry->time_in[HSR_DEV_SLAVE2] +
+					msecs_to_jiffies(MAX_SLAVE_DIFF)))
+				hsr_nl_ringerror(node_entry->MacAddressA, HSR_DEV_SLAVE2);
+		}
+
+		/* Prune old entries */
+		if (time_is_before_jiffies(timestamp +
+					msecs_to_jiffies(HSR_NODE_FORGET_TIME))) {
+			hsr_nl_nodedown(node_entry->MacAddressA);
+			list_del_rcu(&node_entry->mac_list);
+			call_rcu(&node_entry->rcu_head, node_entry_reclaim);
+		}
+	}
+}
+
+
+void hsr_get_node_times(struct hsr_priv *hsr_priv, unsigned char addr[ETH_ALEN],
+			unsigned long *time1, unsigned long *time2)
+{
+	struct node_entry *node;
+
+	rcu_read_lock();
+	node = find_node_by_AddrA(&hsr_priv->node_db, addr);
+	if (!node) {
+		*time1 = 0;
+		*time2 = 0;
+	} else {
+		*time1 = node->time_in[HSR_DEV_SLAVE1];
+		*time2 = node->time_in[HSR_DEV_SLAVE2];
+	}
+	rcu_read_unlock();
+}
diff --git a/net/hsr/hsr_framereg.h b/net/hsr/hsr_framereg.h
new file mode 100644
index 0000000..6e28490
--- /dev/null
+++ b/net/hsr/hsr_framereg.h
@@ -0,0 +1,52 @@
+/*
+ * Copyright 2011-2012 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):
+ *	2011-2012 Arvid Brodin, [email-masked]
+ */
+
+#ifndef _HSR_FRAMEREG_H
+#define _HSR_FRAMEREG_H
+
+#include "hsr_private.h"
+
+enum hsr_dev_idx {
+	HSR_DEV_SLAVE1 = 0,
+	HSR_DEV_SLAVE2,
+	HSR_DEV_MASTER,
+};
+
+struct node_entry;
+
+#define HSR_MAX_SLAVE	(HSR_DEV_SLAVE2 + 1)
+#define HSR_MAX_DEV	(HSR_DEV_MASTER + 1)
+
+struct node_entry *hsr_find_node(struct list_head *node_db, struct sk_buff *skb);
+
+int hsr_merge_node(struct hsr_priv *hsr_priv, enum hsr_dev_idx dev_idx,
+		   struct sk_buff *skb);
+
+void hsr_addr_subst(struct hsr_priv *hsr_priv, struct sk_buff *skb);
+
+void hsr_register_frame_in(struct node_entry *node, enum hsr_dev_idx);
+
+int hsr_register_frame_out(struct node_entry *node, enum hsr_dev_idx,
+			   struct sk_buff *skb);
+
+void hsr_prune_nodes(struct list_head *node_db);
+
+void hsr_get_node_times(struct hsr_priv *hsr_priv, unsigned char addr[ETH_ALEN],
+			unsigned long *time1, unsigned long *time2);
+
+int hsr_create_self_node(struct list_head *self_node_db,
+			 unsigned char addr_a[ETH_ALEN],
+			 unsigned char addr_b[ETH_ALEN]);
+
+unsigned char *hsr_get_node_addr(struct node_entry *node);
+
+#endif /* _HSR_FRAMEREG_H */
diff --git a/net/hsr/hsr_main.c b/net/hsr/hsr_main.c
new file mode 100644
index 0000000..38974f2
--- /dev/null
+++ b/net/hsr/hsr_main.c
@@ -0,0 +1,402 @@
+/*
+ * Copyright 2011-2012 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):
+ *	2011-2012 Arvid Brodin, [email-masked]
+ *
+ * In addition to routines for registering and unregistering HSR support, this
+ * file also contains the receive routine that handles all incoming frames with
+ * Ethertype (protocol) ETH_P_HSR.
+ */
+
+#include <linux/netdevice.h>
+#include <linux/rculist.h>
+#include <linux/timer.h>
+#include <linux/etherdevice.h>
+#include "hsr_private.h"
+#include "hsr_device.h"
+#include "hsr_netlink.h"
+#include "hsr_framereg.h"
+
+
+/* Multicast address for HSR Supervision frames */
+const u8 hsr_multicast_addr[ETH_ALEN] = {0x01, 0x15, 0x4e, 0x00, 0x01, 0x00};
+
+
+/* List of all registered virtual HSR devices */
+static LIST_HEAD(hsr_list);
+
+void register_hsr_master(struct hsr_priv *hsr_priv)
+{
+	list_add_tail_rcu(&hsr_priv->hsr_list, &hsr_list);
+}
+
+void unregister_hsr_master(struct hsr_priv *hsr_priv)
+{
+	struct hsr_priv *hsr_priv_it;
+
+	list_for_each_entry(hsr_priv_it, &hsr_list, hsr_list)
+		if (hsr_priv_it == hsr_priv) {
+			list_del_rcu(&hsr_priv_it->hsr_list);
+			return;
+		}
+}
+
+
+/*
+ * If dev is a HSR slave device, return the virtual master device. Return NULL
+ * otherwise.
+ */
+static struct hsr_priv *get_hsr_master(struct net_device *dev)
+{
+	struct hsr_priv *hsr_priv;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(hsr_priv, &hsr_list, hsr_list)
+		if ((dev == hsr_priv->slave_data[0].dev) ||
+				(dev == hsr_priv->slave_data[1].dev)) {
+			rcu_read_unlock();
+			return hsr_priv;
+		}
+
+	rcu_read_unlock();
+	return NULL;
+}
+
+/*
+ * If dev is a HSR slave device, return the other slave device. Return NULL
+ * otherwise.
+ */
+static struct hsr_slave_data *get_other_slave(struct hsr_priv *hsr_priv,
+					      struct net_device *dev)
+{
+	if (dev == hsr_priv->slave_data[0].dev)
+		return &hsr_priv->slave_data[1];
+	if (dev == hsr_priv->slave_data[1].dev)
+		return &hsr_priv->slave_data[0];
+
+	return NULL;
+}
+
+
+static int hsr_netdev_notify(struct notifier_block *nb, unsigned long event,
+			     void *ptr)
+{
+
+/*
+ * Should do:
+ *
+ * - error monitoring (broken link)
+ * - slave monitoring (disallow down, reconfiguring ?)
+
+	register_netdevice_notifier(...);
+	NETDEV_GOING_DOWN
+	NETDEV_CHANGEADDR
+	NETDEV_CHANGE (dev->flags)
+	NETDEV_UNREGISTER
+ */
+
+	struct net_device *slave, *other_slave;
+	struct hsr_priv *hsr_priv;
+	struct hsr_slave_data *other_data;
+	int old_operstate;
+
+	hsr_priv = get_hsr_master(ptr);
+	if (hsr_priv) { /* Is ptr a slave device? */
+		slave = ptr;
+		other_data = get_other_slave(hsr_priv, slave);
+		other_slave = other_data->dev;
+	} else {
+		if (!is_hsr_master(ptr))
+			return NOTIFY_DONE;
+		hsr_priv = netdev_priv(ptr);
+		slave = hsr_priv->slave_data[0].dev;
+		other_slave = hsr_priv->slave_data[1].dev;
+	}
+
+	switch (event) {
+	case NETDEV_UP:		/* Administrative state DOWN */
+	case NETDEV_DOWN:	/* Administrative state UP */
+	case NETDEV_CHANGE:	/* Link (carrier) state changes */
+		old_operstate = hsr_priv->dev->operstate;
+		hsr_set_carrier(hsr_priv->dev, slave, other_slave);
+		hsr_set_operstate(hsr_priv->dev, slave, other_slave);
+		hsr_check_announce(hsr_priv->dev, old_operstate);
+	}
+
+	return NOTIFY_DONE;
+}
+
+
+static struct timer_list prune_timer;
+
+static void prune_nodes_all(unsigned long data)
+{
+	struct hsr_priv *hsr_priv;
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(hsr_priv, &hsr_list, hsr_list)
+		hsr_prune_nodes(&hsr_priv->node_db);
+	rcu_read_unlock();
+
+	prune_timer.expires = jiffies + msecs_to_jiffies(PRUNE_PERIOD);
+	add_timer(&prune_timer);
+}
+
+
+static struct sk_buff *strip_hsr_tag(struct sk_buff *skb)
+{
+	struct hsr_tag *hsr_tag;
+	struct sk_buff *skb2;
+
+	skb2 = skb_share_check(skb, GFP_ATOMIC);
+	if (unlikely(!skb2))
+		goto err_free;
+	skb = skb2;
+
+	if (unlikely(!pskb_may_pull(skb, HSR_TAGLEN)))
+		goto err_free;
+
+	hsr_tag = (struct hsr_tag *) skb->data;
+	skb->protocol = hsr_tag->encap_proto;
+	skb_reset_network_header(skb);  // FIXME is this needed & correct?
+	skb_pull_rcsum(skb, HSR_TAGLEN);
+
+	return skb;
+
+err_free:
+	kfree_skb(skb);
+	return NULL;
+}
+
+
+/*
+ * The uses I can see for these HSR supervision frames are:
+ * 1) Use the frames that are sent after node initialization ("HSR_TLV.Type =
+ *    22") to reset any sequence_nr counters belonging to that node. Useful if
+ *    the other node's counter has been reset for some reason.
+ *    --
+ *    Or not - resetting the counter and bridging the frame would create a
+ *    loop, unfortunately.
+ *
+ * 2) Use the LifeCheck frames to detect ring breaks. I.e. if no LifeCheck
+ *    frame is received from a particular node, we know something is wrong.
+ *    We just register these (as with normal frames) and throw them away.
+ *
+ * 3) Allow different MAC addresses for the two slave interfaces, using the
+ *    MacAddressA field.
+ */
+static bool handle_supervision_frame(struct hsr_priv *hsr_priv,
+				     enum hsr_dev_idx dev_idx,
+				     struct sk_buff *skb)
+{
+	struct hsr_sup_tag *hsr_stag;
+
+	if (compare_ether_addr(eth_hdr(skb)->h_dest, hsr_multicast_addr))
+		return 0;
+
+	hsr_stag = (struct hsr_sup_tag *) skb->data;
+	if (get_hsr_stag_path(hsr_stag) != 0x0f)
+		return 0;
+	if ((hsr_stag->HSR_TLV_Type != HSR_TLV_ANNOUNCE) &&
+				(hsr_stag->HSR_TLV_Type != HSR_TLV_LIFE_CHECK))
+		return 0;
+	if (hsr_stag->HSR_TLV_Length != 12)
+		return 0;
+
+	skb_pull(skb, sizeof(struct hsr_sup_tag));
+	hsr_merge_node(hsr_priv, dev_idx, skb);
+
+	/* Prepare for forwarding */
+	skb_push(skb, sizeof(struct hsr_sup_tag));
+
+	return 1;
+}
+
+
+/*
+ * Implementation somewhat according to IEC-62439-3, p. 43
+ */
+static int hsr_rcv(struct sk_buff *skb, struct net_device *dev,
+		   struct packet_type *pt, struct net_device *orig_dev)
+{
+	struct hsr_priv *hsr_priv;
+	struct hsr_slave_data *other_slave_data;
+	struct node_entry *node;
+	int deliver_to_self;
+	struct sk_buff *skb_deliver;
+	enum hsr_dev_idx dev_in_idx, dev_other_idx;
+	int ret;
+
+	hsr_priv = get_hsr_master(dev);
+
+	if (!hsr_priv) {
+		netdev_info(dev, "HSR: Got HSR frame on non-HSR device; "
+							"dropping it.\n");
+		kfree_skb(skb);
+		return NET_RX_DROP;
+	}
+
+	if (dev == hsr_priv->slave_data[0].dev) {
+		dev_in_idx = HSR_DEV_SLAVE1;
+		dev_other_idx = HSR_DEV_SLAVE2;
+	} else {
+		dev_in_idx = HSR_DEV_SLAVE2;
+		dev_other_idx = HSR_DEV_SLAVE1;
+	}
+
+	node = hsr_find_node(&hsr_priv->self_node_db, skb);
+	if (node) {
+		/* Always kill frames sent by ourselves */
+		kfree_skb(skb);
+		return NET_RX_SUCCESS;
+	}
+
+	/* Receive this frame? */
+	deliver_to_self = 0;
+	if ((skb->pkt_type == PACKET_HOST) ||
+				(skb->pkt_type == PACKET_MULTICAST) ||
+				(skb->pkt_type == PACKET_BROADCAST))
+		deliver_to_self = 1;
+	else if (!compare_ether_addr(eth_hdr(skb)->h_dest,
+						hsr_priv->dev->dev_addr)) {
+		skb->pkt_type = PACKET_HOST;
+		deliver_to_self = 1;
+	}
+
+	if (handle_supervision_frame(hsr_priv, dev_in_idx, skb) == 1)
+		deliver_to_self = 0;
+
+	rcu_read_lock(); /* node_db */
+	node = hsr_find_node(&hsr_priv->node_db, skb);
+	if (!node) {
+		/* Source node unknown; don't create a network loop */
+		rcu_read_unlock();
+		netdev_info(dev, "HSR: Got HSR frame from unknown node %pM: "
+				 "dropping it.\n",
+				 eth_hdr(skb)->h_source);
+		kfree_skb(skb);
+		return NET_RX_DROP;
+	}
+
+	if (hsr_register_frame_out(node, HSR_DEV_MASTER, skb) == 1)
+		deliver_to_self = 0;
+
+	hsr_register_frame_in(node, dev_in_idx);
+
+	/* Forward this frame? */
+	other_slave_data = NULL;
+	if (skb->pkt_type != PACKET_HOST) {
+		other_slave_data = get_other_slave(hsr_priv, dev);
+		if (hsr_register_frame_out(node, dev_other_idx, skb) == 1)
+			other_slave_data = NULL;
+	}
+
+	rcu_read_unlock(); /* node_db */
+
+	if (!deliver_to_self && !other_slave_data) {
+		kfree_skb(skb);
+		return NET_RX_SUCCESS;
+	}
+
+	skb_deliver = skb;
+	if (deliver_to_self && other_slave_data) {
+#if !defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
+		/* We have to memmove the whole payload below */
+		skb_deliver = skb_copy(skb, GFP_ATOMIC);
+#else
+		skb_deliver = skb_clone(skb, GFP_ATOMIC);
+#endif
+		if (!skb_deliver) {
+			deliver_to_self = 0;
+			hsr_priv->dev->stats.rx_dropped++;
+		}
+	}
+
+	if (deliver_to_self) {
+		skb_deliver = strip_hsr_tag(skb_deliver);
+		if (!skb_deliver) {
+			hsr_priv->dev->stats.rx_dropped++;
+			goto forward;
+		}
+#if !defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
+		/*
+		 * skb_deliver should be linear here, after the call to
+		 * skb_copy() above. We need to memmove the whole payload to
+		 * work around alignment problems caused by the 6-byte HSR tag.
+		 */
+		memmove(skb_deliver->data - HSR_TAGLEN, skb_deliver->data,
+							skb_deliver->len);
+		skb_deliver->data -= HSR_TAGLEN;
+		skb_deliver->tail -= HSR_TAGLEN;
+		skb_reset_network_header(skb_deliver); // FIXME is this needed?
+#endif
+		skb_deliver->dev = hsr_priv->dev;
+		hsr_addr_subst(hsr_priv, skb_deliver);
+		ret = netif_rx(skb_deliver);
+		if (ret == NET_RX_DROP)
+			hsr_priv->dev->stats.rx_dropped++;
+		else {
+			hsr_priv->dev->stats.rx_packets++;
+			hsr_priv->dev->stats.rx_bytes += skb->len;
+		}
+	}
+
+forward:
+	if (other_slave_data) {
+		skb_push(skb, ETH_HLEN);
+		skb->dev = other_slave_data->dev;
+		dev_queue_xmit(skb);
+	}
+
+	return NET_RX_SUCCESS;
+}
+
+
+static struct packet_type hsr_pt __read_mostly = {
+	.type = htons(ETH_P_HSR),
+	.func = hsr_rcv,
+};
+
+static struct notifier_block hsr_nb = {
+	.notifier_call = hsr_netdev_notify,	/* Slave event notifications */
+};
+
+
+static int __init hsr_init(void)
+{
+	int res;
+
+	BUG_ON(sizeof(struct hsr_tag) != HSR_TAGLEN);
+
+	dev_add_pack(&hsr_pt);
+
+	init_timer(&prune_timer);
+	prune_timer.function = prune_nodes_all;
+	prune_timer.data = 0;
+	prune_timer.expires = jiffies + msecs_to_jiffies(PRUNE_PERIOD);
+	add_timer(&prune_timer);
+
+	register_netdevice_notifier(&hsr_nb);
+
+	res = hsr_netlink_init();
+
+	return res;
+}
+
+static void __exit hsr_exit(void)
+{
+	unregister_netdevice_notifier(&hsr_nb);
+	del_timer(&prune_timer);
+	hsr_netlink_exit();
+	dev_remove_pack(&hsr_pt);
+}
+
+module_init(hsr_init);
+module_exit(hsr_exit);
+MODULE_LICENSE("GPL");
diff --git a/net/hsr/hsr_netlink.c b/net/hsr/hsr_netlink.c
new file mode 100644
index 0000000..40e31f4
--- /dev/null
+++ b/net/hsr/hsr_netlink.c
@@ -0,0 +1,293 @@
+/*
+ * Copyright 2011-2012 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):
+ *	2011-2012 Arvid Brodin, [email-masked]
+ *
+ * Routines for handling Netlink messages for HSR.
+ */
+
+#include "hsr_netlink.h"
+#include <linux/kernel.h>
+#include <net/rtnetlink.h>
+#include <net/genetlink.h>
+#include "hsr_private.h"
+#include "hsr_device.h"
+#include "hsr_framereg.h"
+
+static const struct nla_policy hsr_policy[IFLA_HSR_MAX + 1] = {
+	[IFLA_HSR_SLAVE1]	= { .type = NLA_U32 },
+	[IFLA_HSR_SLAVE2]	= { .type = NLA_U32 },
+};
+
+
+/*
+ * Here, it seems a netdevice has already been allocated for us, and the
+ * hsr_dev_setup routine has been executed. Nice!
+ */
+static int hsr_newlink(struct net *src_net, struct net_device *dev,
+		       struct nlattr *tb[], struct nlattr *data[])
+{
+	struct net_device *link[2];
+
+	if (!data[IFLA_HSR_SLAVE1]) {
+		netdev_info(dev, "IFLA_HSR_SLAVE1 missing!\n");
+		return -EINVAL;
+	}
+	link[0] = __dev_get_by_index(src_net, nla_get_u32(data[IFLA_HSR_SLAVE1]));
+	if (!data[IFLA_HSR_SLAVE2]) {
+		netdev_info(dev, "IFLA_HSR_SLAVE2 missing!\n");
+		return -EINVAL;
+	}
+	link[1] = __dev_get_by_index(src_net, nla_get_u32(data[IFLA_HSR_SLAVE2]));
+
+	if (!link[0] || !link[1])
+		return -ENODEV;
+	if (link[0] == link[1])
+		return -EINVAL;
+
+	return hsr_dev_finalize(dev, link);
+}
+
+static struct rtnl_link_ops hsr_link_ops __read_mostly = {
+	.kind		= "hsr",
+	.maxtype	= IFLA_HSR_MAX,
+	.policy		= hsr_policy,
+	.priv_size	= sizeof(struct hsr_priv),
+	.setup		= hsr_dev_setup,
+//	.validate	= vlan_validate,
+	.newlink	= hsr_newlink,
+//	.changelink	= vlan_changelink,
+//	.dellink	= hsr_dellink,  dev->destructor() called automatically?
+//	.get_size	= vlan_get_size,
+//	.fill_info	= vlan_fill_info,
+};
+
+
+
+/* attribute policy */
+/* NLA_BINARY missing in libnl; use unspec in userspace instead. */
+static const struct nla_policy hsr_genl_policy[HSR_A_MAX + 1] = {
+	[HSR_A_NODE_ADDR] = { .type = NLA_BINARY, .len = ETH_ALEN },
+	[HSR_A_IFINDEX] = { .type = NLA_U32 },
+	[HSR_A_IF1AGE] = { .type = NLA_U32 }, /* 32-bit int */
+	[HSR_A_IF2AGE] = { .type = NLA_U32 }, /* 32-bit int */
+};
+
+static struct genl_family hsr_genl_family = {
+	.id = GENL_ID_GENERATE,
+	.hdrsize = 0,
+	.name = "HSR",
+	.version = 1,
+	.maxattr = HSR_A_MAX,
+};
+
+static struct genl_multicast_group hsr_network_genl_mcgrp = {
+	.name = "hsr-network",
+};
+
+static int hsr_genl_seq = 0;
+
+
+
+static struct sk_buff *hsr_create_genl_msg(void **pmsg_head, unsigned gfp,
+					   int cmd)
+{
+	struct sk_buff *skb;
+
+	skb = genlmsg_new(NLMSG_GOODSIZE, gfp);
+	if (!skb)
+		return NULL;
+
+	*pmsg_head = genlmsg_put(skb, 0, hsr_genl_seq++, &hsr_genl_family, 0,
+									cmd);
+	if (!pmsg_head) {
+		kfree_skb(skb);
+		return NULL;
+	}
+
+	return skb;
+}
+
+
+/*
+ * This is called if for some node with MAC address addr, we only get frames
+ * over one of the slave interfaces. This would indicate an open network ring
+ * (i.e. a link has failed somewhere).
+ */
+void hsr_nl_ringerror(unsigned char addr[ETH_ALEN], int dev_idx)
+{
+	struct sk_buff *skb;
+	void *msg_head;
+
+	skb = hsr_create_genl_msg(&msg_head, GFP_ATOMIC, HSR_C_RING_ERROR);
+	if (!skb)
+		return;
+
+	NLA_PUT(skb, HSR_A_NODE_ADDR, ETH_ALEN, addr);
+	NLA_PUT_U32(skb, HSR_A_IFINDEX, dev_idx);
+
+	genlmsg_end(skb, msg_head);
+	genlmsg_multicast(skb, 0, hsr_network_genl_mcgrp.id, GFP_ATOMIC);
+
+	return;
+
+nla_put_failure:
+	kfree_skb(skb);
+}
+
+/*
+ * This is called when we haven't heard from the node with MAC address addr for
+ * some time (just before the node is removed from the node table/list).
+ */
+void hsr_nl_nodedown(unsigned char addr[ETH_ALEN])
+{
+	struct sk_buff *skb;
+	void *msg_head;
+
+	skb = hsr_create_genl_msg(&msg_head, GFP_ATOMIC, HSR_C_NODE_DOWN);
+	if (!skb)
+		return;
+
+	NLA_PUT(skb, HSR_A_NODE_ADDR, ETH_ALEN, addr);
+
+	genlmsg_end(skb, msg_head);
+	genlmsg_multicast(skb, 0, hsr_network_genl_mcgrp.id, GFP_ATOMIC);
+
+	return;
+
+nla_put_failure:
+	kfree_skb(skb);
+}
+
+/*
+ * HSR_C_GET_NODE_STATUS lets userspace query the internal HSR node table
+ * about the status of a specific node in the network, defined by its MAC
+ * address.
+ *
+ * Input: hsr ifindex, node mac address
+ * Output: hsr ifindex, node mac address (copied from request),
+ *	   age of latest frame from node over slave 1, slave 2 [ms]
+ */
+static int hsr_get_node_status(struct sk_buff *skb_in, struct genl_info *info)
+{
+	/* For receiving */
+	struct nlattr *na;
+	char *node_addr;
+	struct net_device *hsr_dev;
+
+	/* For sending */
+	struct sk_buff *skb_out;
+	void *msg_head;
+	struct hsr_priv *hsr_priv;
+	unsigned long time1, time2;
+
+	if (!info)
+		goto invalid;
+
+	na = info->attrs[HSR_A_IFINDEX];
+	if (!na)
+		goto invalid;
+	na = info->attrs[HSR_A_NODE_ADDR];
+	if (!na)
+		goto invalid;
+
+	hsr_dev = __dev_get_by_index(genl_info_net(info),
+					nla_get_u32(info->attrs[HSR_A_IFINDEX]));
+	if (!hsr_dev)
+		goto invalid;
+	if (!is_hsr_master(hsr_dev))
+		goto invalid;
+
+
+	/* Send reply */
+
+	skb_out = hsr_create_genl_msg(&msg_head, GFP_ATOMIC,
+							HSR_C_SET_NODE_STATUS);
+	if (!skb_out)
+		return -ENOMEM;
+
+	NLA_PUT_U32(skb_out, HSR_A_IFINDEX, hsr_dev->ifindex);
+
+	node_addr = nla_data(info->attrs[HSR_A_NODE_ADDR]);
+	NLA_PUT(skb_out, HSR_A_NODE_ADDR, ETH_ALEN, node_addr);
+
+	hsr_priv = netdev_priv(hsr_dev);
+	hsr_get_node_times(hsr_priv, node_addr, &time1, &time2);
+
+	NLA_PUT_U32(skb_out, HSR_A_IF1AGE, time1 ?
+					jiffies_to_msecs(jiffies - time1) : -1);
+	NLA_PUT_U32(skb_out, HSR_A_IF2AGE, time2 ?
+					jiffies_to_msecs(jiffies - time2) : -1);
+
+	genlmsg_end(skb_out, msg_head);
+	genlmsg_unicast(genl_info_net(info), skb_out, info->snd_pid);
+
+	return 0;
+
+nla_put_failure:
+	kfree_skb(skb_out);
+
+	return -ENOMEM;
+
+invalid:
+	return -EINVAL;
+}
+
+static struct genl_ops hsr_ops_get_node_status = {
+	.cmd = HSR_C_GET_NODE_STATUS,
+	.flags = 0,
+	.policy = hsr_genl_policy,
+	.doit = hsr_get_node_status,
+	.dumpit = NULL,
+};
+
+
+int __init hsr_netlink_init(void)
+{
+	int rc;
+
+	rc = rtnl_link_register(&hsr_link_ops);
+	if (rc)
+		goto fail_rtnl_link_register;
+
+	rc = genl_register_family(&hsr_genl_family);
+	if (rc)
+		goto fail_genl_register_family;
+
+	rc = genl_register_ops(&hsr_genl_family, &hsr_ops_get_node_status);
+	if (rc)
+		goto fail_genl_register_ops;
+
+	rc = genl_register_mc_group(&hsr_genl_family, &hsr_network_genl_mcgrp);
+	if (rc)
+		goto fail_genl_register_mc_group;
+
+	return 0;
+
+fail_genl_register_mc_group:
+	genl_unregister_ops(&hsr_genl_family, &hsr_ops_get_node_status);
+fail_genl_register_ops:
+	genl_unregister_family(&hsr_genl_family);
+fail_genl_register_family:
+	rtnl_link_unregister(&hsr_link_ops);
+fail_rtnl_link_register:
+
+	return rc;
+}
+
+void __exit hsr_netlink_exit(void)
+{
+	genl_unregister_mc_group(&hsr_genl_family, &hsr_network_genl_mcgrp);
+	genl_unregister_ops(&hsr_genl_family, &hsr_ops_get_node_status);
+	genl_unregister_family(&hsr_genl_family);
+
+	rtnl_link_unregister(&hsr_link_ops);
+}
+
+MODULE_ALIAS_RTNL_LINK("hsr");
diff --git a/net/hsr/hsr_netlink.h b/net/hsr/hsr_netlink.h
new file mode 100644
index 0000000..4282d9f
--- /dev/null
+++ b/net/hsr/hsr_netlink.h
@@ -0,0 +1,64 @@
+/*
+ * Copyright 2011-2012 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):
+ *	2011-2012 Arvid Brodin, [email-masked]
+ */
+
+#ifndef __HSR_NETLINK_H
+#define __HSR_NETLINK_H
+
+/* attributes */
+enum {
+	HSR_A_UNSPEC,
+	HSR_A_NODE_ADDR,
+	HSR_A_IFINDEX,
+	HSR_A_IF1AGE,
+	HSR_A_IF2AGE,
+	__HSR_A_MAX,
+};
+#define HSR_A_MAX (__HSR_A_MAX - 1)
+
+
+#ifdef __KERNEL__
+
+#include <linux/if_ether.h>
+#include <linux/module.h>
+
+int __init hsr_netlink_init(void);
+void __exit hsr_netlink_exit(void);
+
+void hsr_nl_ringerror(unsigned char addr[ETH_ALEN], int dev_idx);
+void hsr_nl_nodedown(unsigned char addr[ETH_ALEN]);
+void hsr_nl_framedrop(int dropcount, int dev_idx);
+void hsr_nl_linkdown(int dev_idx);
+
+
+/*
+ * Generic Netlink HSR family definition
+ */
+
+
+#endif /* __KERNEL__ */
+
+
+
+/* commands */
+enum {
+	HSR_C_UNSPEC,
+	HSR_C_RING_ERROR,
+	HSR_C_NODE_DOWN,
+	HSR_C_GET_NODE_STATUS,
+	HSR_C_SET_NODE_STATUS,
+	__HSR_C_MAX,
+};
+#define HSR_C_MAX (__HSR_C_MAX - 1)
+
+
+
+#endif /* __HSR_NETLINK_H */
diff --git a/net/hsr/hsr_private.h b/net/hsr/hsr_private.h
new file mode 100644
index 0000000..50c8784
--- /dev/null
+++ b/net/hsr/hsr_private.h
@@ -0,0 +1,162 @@
+/*
+ * Copyright 2011-2012 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):
+ *	2011-2012 Arvid Brodin, [email-masked]
+ */
+
+#ifndef _HSR_PRIVATE_H
+#define _HSR_PRIVATE_H
+
+#include <linux/netdevice.h>
+#include <linux/list.h>
+
+
+/*
+ * Time constants as specified in the HSR specification (IEC-62439-3 2010)
+ * Table 8.
+ * All values in milliseconds.
+ */
+#define HSR_LIFE_CHECK_INTERVAL		 2000 /* ms */
+#define HSR_NODE_FORGET_TIME		60000 /* ms */
+#define HSR_ANNOUNCE_INTERVAL		  100 /* ms */
+
+/*
+ * By how much may slave1 and slave2 timestamps of latest received frame from
+ * each node differ before we notify of communication problem?
+ */
+#define MAX_SLAVE_DIFF			 3000 /* ms */
+
+/*
+ * How often shall we check for broken ring and remove node entries older than
+ * HSR_NODE_FORGET_TIME?
+ */
+#define PRUNE_PERIOD			 3000 /* ms */
+
+
+#define HSR_TLV_ANNOUNCE		   22
+#define HSR_TLV_LIFE_CHECK		   23
+
+
+/*
+ * HSR Tag.
+ * As defined in IEC-62439-3:2010, the HSR tag is really { ethertype = 0x88FB,
+ * path, LSDU_size, sequence Nr }. But we let eth_header() create { h_dest,
+ * h_source, h_proto = 0x88FB }, and add { path, LSDU_size, sequence Nr,
+ * encapsulated protocol } instead.
+ */
+#define HSR_TAGLEN	6
+
+/* Field names below as defined in the IEC:2010 standard for HSR. */
+struct hsr_tag {
+	__be16		path_and_LSDU_size;
+	__be16		sequence_nr;
+	__be16		encap_proto;
+} __packed;
+
+/*
+ * The helper functions below assumes that 'path' occupies the 4 most
+ * significant bits of the 16-bit field shared by 'path' and 'LSDU_size' (or
+ * equivalently, the 4 most significant bits of HSR tag byte 14).
+ *
+ * This is unclear in the IEC specification; its definition of MAC addresses
+ * indicates the spec is written with the least significant bit first (to the
+ * left). This, however, would mean that the LSDU field would be split in two
+ * with the path field in-between, which seems strange. I'm guessing the MAC
+ * address definition is in error.
+ */
+static inline u16 get_hsr_tag_path(struct hsr_tag *ht)
+{
+	return ntohs(ht->path_and_LSDU_size) >> 12;
+}
+
+static inline u16 get_hsr_tag_LSDU_size(struct hsr_tag *ht)
+{
+	return ntohs(ht->path_and_LSDU_size) & 0x0FFF;
+}
+
+static inline void set_hsr_tag_path(struct hsr_tag *ht, u16 path)
+{
+	ht->path_and_LSDU_size = htons(
+			(ntohs(ht->path_and_LSDU_size) & 0x0FFF) | (path << 12));
+}
+
+static inline void set_hsr_tag_LSDU_size(struct hsr_tag *ht, u16 LSDU_size)
+{
+	ht->path_and_LSDU_size = htons(
+			(ntohs(ht->path_and_LSDU_size) & 0xF000) |
+			(LSDU_size & 0x0FFF));
+}
+
+struct hsr_ethhdr {
+	struct ethhdr	ethhdr;
+	struct hsr_tag	hsr_tag;
+} __packed;
+
+
+/*
+ * HSR Supervision Frame data types.
+ * Field names as defined in the IEC:2010 standard for HSR.
+ */
+struct hsr_sup_tag {
+	__be16		path_and_HSR_Ver;
+	__be16		sequence_nr;
+	__u8		HSR_TLV_Type;
+	__u8		HSR_TLV_Length;
+} __packed;
+
+struct hsr_sup_payload {
+	unsigned char	MacAddressA[ETH_ALEN];
+} __packed;
+
+static inline u16 get_hsr_stag_path(struct hsr_sup_tag *hst)
+{
+	return get_hsr_tag_path((struct hsr_tag *) hst);
+}
+
+static inline u16 get_hsr_stag_HSR_ver(struct hsr_sup_tag *hst)
+{
+	return get_hsr_tag_LSDU_size((struct hsr_tag *) hst);
+}
+
+static inline void set_hsr_stag_path(struct hsr_sup_tag *hst, u16 path)
+{
+	set_hsr_tag_path((struct hsr_tag *) hst, path);
+}
+
+static inline void set_hsr_stag_HSR_Ver(struct hsr_sup_tag *hst, u16 HSR_Ver)
+{
+	set_hsr_tag_LSDU_size((struct hsr_tag *) hst, HSR_Ver);
+}
+
+
+struct hsr_slave_data {
+	struct net_device	*dev;
+	int promisc;
+	int was_up;
+};
+
+struct hsr_priv {
+	struct list_head	hsr_list;	/* List of hsr devices */
+	struct rcu_head		rcu_head;
+	struct net_device	*dev;
+	struct hsr_slave_data	slave_data[2];
+	struct list_head	node_db;	/* Other HSR nodes */
+	struct list_head	self_node_db;	/* MACs of slaves */
+	struct timer_list	announce_timer;	/* Supervision frame dispatch */
+	int announce_count;
+	u16 sequence_nr;
+	spinlock_t seqnr_lock;			/* locking for sequence_nr */
+};
+
+extern const u8 hsr_multicast_addr[ETH_ALEN];
+
+void register_hsr_master(struct hsr_priv *hsr_priv);
+void unregister_hsr_master(struct hsr_priv *hsr_priv);
+
+#endif /*  _HSR_PRIVATE_H */

-- 
Arvid Brodin | Consultant (Linux)
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