/* 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
 */

#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 */
#define HSR_SEQNR_START			(USHRT_MAX - 1024)
#define HSR_SUP_SEQNR_START		(HSR_SEQNR_START / 2)


/* 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.
 *
 * Field names as defined in the IEC:2010 standard for HSR.
 */
struct hsr_tag {
	__be16		path_and_LSDU_size;
	__be16		sequence_nr;
	__be16		encap_proto;
} __packed;

#define HSR_HLEN	6

#define HSR_V1_SUP_LSDUSIZE		52

/* 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 hsrv0_ethhdr_sp {
	struct ethhdr		ethhdr;
	struct hsr_sup_tag	hsr_sup;
} __packed;

struct hsrv1_ethhdr_sp {
	struct ethhdr		ethhdr;
	struct hsr_tag		hsr;
	struct hsr_sup_tag	hsr_sup;
} __packed;


enum hsr_port_type {
	HSR_PT_NONE = 0,	/* Must be 0, used by framereg */
	HSR_PT_SLAVE_A,
	HSR_PT_SLAVE_B,
	HSR_PT_INTERLINK,
	HSR_PT_MASTER,
	HSR_PT_PORTS,	/* This must be the last item in the enum */
};

struct hsr_port {
	struct list_head	port_list;
	struct net_device	*dev;
	struct hsr_priv		*hsr;
	enum hsr_port_type	type;
};

struct hsr_priv {
	struct rcu_head		rcu_head;
	struct list_head	ports;
	struct list_head	node_db;	/* Known HSR nodes */
	struct list_head	self_node_db;	/* MACs of slaves */
	struct timer_list	announce_timer;	/* Supervision frame dispatch */
	struct timer_list	prune_timer;
	int announce_count;
	u16 sequence_nr;
	u16 sup_sequence_nr;			/* For HSRv1 separate seq_nr for supervision */
	u8 protVersion;					/* Indicate if HSRv0 or HSRv1. */
	spinlock_t seqnr_lock;			/* locking for sequence_nr */
	unsigned char		sup_multicast_addr[ETH_ALEN];
};

#define hsr_for_each_port(hsr, port) \
	list_for_each_entry_rcu((port), &(hsr)->ports, port_list)

struct hsr_port *hsr_port_get_hsr(struct hsr_priv *hsr, enum hsr_port_type pt);

/* Caller must ensure skb is a valid HSR frame */
static inline u16 hsr_get_skb_sequence_nr(struct sk_buff *skb)
{
	struct hsr_ethhdr *hsr_ethhdr;

	hsr_ethhdr = (struct hsr_ethhdr *) skb_mac_header(skb);
	return ntohs(hsr_ethhdr->hsr_tag.sequence_nr);
}

#endif /*  __HSR_PRIVATE_H */