net/hsr: Add support for the High-availability Seamless Redundancy protocol (HSRv0)

High-availability Seamless Redundancy ("HSR") provides instant failover
redundancy for Ethernet networks. It requires a special network topology where
all nodes are connected in a ring (each node having two physical network
interfaces). It is suited for applications that demand high availability and
very short reaction time.

HSR acts on the Ethernet layer, using a registered Ethernet protocol type to
send special HSR frames in both directions over the ring. The driver creates
virtual network interfaces that can be used just like any ordinary Linux
network interface, for IP/TCP/UDP traffic etc. All nodes in the network ring
must be HSR capable.

This code is a "best effort" to comply with the HSR standard as described in
IEC 62439-3:2010 (HSRv0).
Signed-off-by: Arvid Brodin <arvid.brodin@xdin.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/hsr_netlink.h

+/*
+ * Copyright 2011-2013 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):
+ *	2011-2013 Arvid Brodin, arvid.brodin@xdin.com
+ */
+
+#ifndef __UAPI_HSR_NETLINK_H
+#define __UAPI_HSR_NETLINK_H
+
+/* Generic Netlink HSR family definition
+ */
+
+/* attributes */
+enum {
+	HSR_A_UNSPEC,
+	HSR_A_NODE_ADDR,
+	HSR_A_IFINDEX,
+	HSR_A_IF1_AGE,
+	HSR_A_IF2_AGE,
+	HSR_A_NODE_ADDR_B,
+	HSR_A_IF1_SEQ,
+	HSR_A_IF2_SEQ,
+	HSR_A_IF1_IFINDEX,
+	HSR_A_IF2_IFINDEX,
+	HSR_A_ADDR_B_IFINDEX,
+	__HSR_A_MAX,
+};
+#define HSR_A_MAX (__HSR_A_MAX - 1)
+
+
+/* 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_GET_NODE_LIST,
+	HSR_C_SET_NODE_LIST,
+	__HSR_C_MAX,
+};
+#define HSR_C_MAX (__HSR_C_MAX - 1)
+
+#endif /* __UAPI_HSR_NETLINK_H */

include/uapi/linux/if_ether.h

@@ -85,6 +85,7 @@
 #define ETH_P_8021AH	0x88E7          /* 802.1ah Backbone Service Tag */
 #define ETH_P_MVRP	0x88F5          /* 802.1Q MVRP                  */
 #define ETH_P_1588	0x88F7		/* IEEE 1588 Timesync */
+#define ETH_P_PRP	0x88FB		/* IEC 62439-3 PRP/HSRv0	*/
 #define ETH_P_FCOE	0x8906		/* Fibre Channel over Ethernet  */
 #define ETH_P_TDLS	0x890D          /* TDLS */
 #define ETH_P_FIP	0x8914		/* FCoE Initialization Protocol */

include/uapi/linux/if_link.h

@@ -481,4 +481,17 @@ enum {
 
 #define IFLA_IPOIB_MAX (__IFLA_IPOIB_MAX - 1)
 
+
+/* HSR section */
+
+enum {
+	IFLA_HSR_UNSPEC,
+	IFLA_HSR_SLAVE1,
+	IFLA_HSR_SLAVE2,
+	IFLA_HSR_MULTICAST_SPEC,
+	__IFLA_HSR_MAX,
+};
+
+#define IFLA_HSR_MAX (__IFLA_HSR_MAX - 1)
+
 #endif /* _UAPI_LINUX_IF_LINK_H */

net/Kconfig

@@ -220,6 +220,7 @@ source "net/openvswitch/Kconfig"
 source "net/vmw_vsock/Kconfig"
 source "net/netlink/Kconfig"
 source "net/mpls/Kconfig"
+source "net/hsr/Kconfig"
 
 config RPS
 	boolean

net/Makefile

@@ -71,3 +71,4 @@ obj-$(CONFIG_NFC)		+= nfc/
 obj-$(CONFIG_OPENVSWITCH)	+= openvswitch/
 obj-$(CONFIG_VSOCKETS)	+= vmw_vsock/
 obj-$(CONFIG_NET_MPLS_GSO)	+= mpls/
+obj-$(CONFIG_HSR)		+= hsr/

net/hsr/Kconfig

+#
+# 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 it 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 62439-3:2010 (HSRv0), 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!
+
+	  If unsure, say N.

net/hsr/Makefile

+#
+# Makefile for HSR
+#
+
+obj-$(CONFIG_HSR)	+= hsr.o
+
+hsr-y			:= hsr_main.o hsr_framereg.o hsr_device.o hsr_netlink.o

net/hsr/hsr_device.h

+/* Copyright 2011-2013 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):
+ *	2011-2013 Arvid Brodin, arvid.brodin@xdin.com
+ */
+
+#ifndef __HSR_DEVICE_H
+#define __HSR_DEVICE_H
+
+#include <linux/netdevice.h>
+#include "hsr_main.h"
+
+void hsr_dev_setup(struct net_device *dev);
+int hsr_dev_finalize(struct net_device *hsr_dev, struct net_device *slave[2],
+		     unsigned char multicast_spec);
+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);
+int hsr_get_max_mtu(struct hsr_priv *hsr_priv);
+
+#endif /* __HSR_DEVICE_H */

net/hsr/hsr_framereg.h

+/* Copyright 2011-2013 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):
+ *	2011-2013 Arvid Brodin, arvid.brodin@xdin.com
+ */
+
+#ifndef _HSR_FRAMEREG_H
+#define _HSR_FRAMEREG_H
+
+#include "hsr_main.h"
+
+struct node_entry;
+
+struct node_entry *hsr_find_node(struct list_head *node_db, struct sk_buff *skb);
+
+struct node_entry *hsr_merge_node(struct hsr_priv *hsr_priv,
+				  struct node_entry *node,
+				  struct sk_buff *skb,
+				  enum hsr_dev_idx dev_idx);
+
+void hsr_addr_subst_source(struct hsr_priv *hsr_priv, struct sk_buff *skb);
+void hsr_addr_subst_dest(struct hsr_priv *hsr_priv, struct ethhdr *ethhdr,
+			 enum hsr_dev_idx dev_idx);
+
+void hsr_register_frame_in(struct node_entry *node, enum hsr_dev_idx dev_idx);
+
+int hsr_register_frame_out(struct node_entry *node, enum hsr_dev_idx dev_idx,
+			   struct sk_buff *skb);
+
+void hsr_prune_nodes(struct hsr_priv *hsr_priv);
+
+int hsr_create_self_node(struct list_head *self_node_db,
+			 unsigned char addr_a[ETH_ALEN],
+			 unsigned char addr_b[ETH_ALEN]);
+
+void *hsr_get_next_node(struct hsr_priv *hsr_priv, void *_pos,
+			unsigned char addr[ETH_ALEN]);
+
+int hsr_get_node_data(struct hsr_priv *hsr_priv,
+		      const unsigned char *addr,
+		      unsigned char addr_b[ETH_ALEN],
+		      unsigned int *addr_b_ifindex,
+		      int *if1_age,
+		      u16 *if1_seq,
+		      int *if2_age,
+		      u16 *if2_seq);
+
+#endif /* _HSR_FRAMEREG_H */

net/hsr/hsr_main.h

+/* Copyright 2011-2013 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):
+ *	2011-2013 Arvid Brodin, arvid.brodin@xdin.com
+ */
+
+#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_ethhdr_sp {
+	struct ethhdr		ethhdr;
+	struct hsr_sup_tag	hsr_sup;
+} __packed;
+
+
+enum hsr_dev_idx {
+	HSR_DEV_NONE = -1,
+	HSR_DEV_SLAVE_A = 0,
+	HSR_DEV_SLAVE_B,
+	HSR_DEV_MASTER,
+};
+#define HSR_MAX_SLAVE	(HSR_DEV_SLAVE_B + 1)
+#define HSR_MAX_DEV	(HSR_DEV_MASTER + 1)
+
+struct hsr_priv {
+	struct list_head	hsr_list;	/* List of hsr devices */
+	struct rcu_head		rcu_head;
+	struct net_device	*dev;
+	struct net_device	*slave[HSR_MAX_SLAVE];
+	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 */
+	unsigned char		sup_multicast_addr[ETH_ALEN];
+};
+
+void register_hsr_master(struct hsr_priv *hsr_priv);
+void unregister_hsr_master(struct hsr_priv *hsr_priv);
+bool is_hsr_slave(struct net_device *dev);
+
+#endif /*  _HSR_PRIVATE_H */

net/hsr/hsr_netlink.h

+/* Copyright 2011-2013 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):
+ *	2011-2013 Arvid Brodin, arvid.brodin@xdin.com
+ */
+
+#ifndef __HSR_NETLINK_H
+#define __HSR_NETLINK_H
+
+#include <linux/if_ether.h>
+#include <linux/module.h>
+#include <uapi/linux/hsr_netlink.h>
+
+struct hsr_priv;
+
+int __init hsr_netlink_init(void);
+void __exit hsr_netlink_exit(void);
+
+void hsr_nl_ringerror(struct hsr_priv *hsr_priv, unsigned char addr[ETH_ALEN],
+		      int dev_idx);
+void hsr_nl_nodedown(struct hsr_priv *hsr_priv, unsigned char addr[ETH_ALEN]);
+void hsr_nl_framedrop(int dropcount, int dev_idx);
+void hsr_nl_linkdown(int dev_idx);
+
+#endif /* __HSR_NETLINK_H */