/* SPDX-License-Identifier: GPL-2.0 */
/* Copyright 2011-2014 Autronica Fire and Security AS
 *
 * Author(s):
 *      2011-2014 Arvid Brodin, arvid.brodin@alten.se
 *
 * include file for HSR and PRP.
 */

#ifndef __HSR_PRIVATE_H
#define __HSR_PRIVATE_H

#include <linux/netdevice.h>
#include <linux/list.h>
#include <linux/if_vlan.h>
#include <linux/if_hsr.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 */
#define HSR_ENTRY_FORGET_TIME             400 /* 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
/* PRP V1 life check for Duplicate discard */
#define PRP_TLV_LIFE_CHECK_DD              20
/* PRP V1 life check for Duplicate Accept */
#define PRP_TLV_LIFE_CHECK_DA              21

/* 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 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;

struct hsr_vlan_ethhdr {
        struct vlan_ethhdr vlanhdr;
        struct hsr_tag  hsr_tag;
} __packed;

/* HSR/PRP 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   macaddress_A[ETH_ALEN];
} __packed;

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 */
};

/* PRP Redunancy Control Trailor (RCT).
 * As defined in IEC-62439-4:2012, the PRP RCT is really { sequence Nr,
 * Lan indentifier (LanId), LSDU_size and PRP_suffix = 0x88FB }.
 *
 * Field names as defined in the IEC:2012 standard for PRP.
 */
struct prp_rct {
        __be16          sequence_nr;
        __be16          lan_id_and_LSDU_size;
        __be16          PRP_suffix;
} __packed;

static inline u16 get_prp_LSDU_size(struct prp_rct *rct)
{
        return ntohs(rct->lan_id_and_LSDU_size) & 0x0FFF;
}

static inline void set_prp_lan_id(struct prp_rct *rct, u16 lan_id)
{
        rct->lan_id_and_LSDU_size = htons((ntohs(rct->lan_id_and_LSDU_size) &
                                          0x0FFF) | (lan_id << 12));
}
static inline void set_prp_LSDU_size(struct prp_rct *rct, u16 LSDU_size)
{
        rct->lan_id_and_LSDU_size = htons((ntohs(rct->lan_id_and_LSDU_size) &
                                          0xF000) | (LSDU_size & 0x0FFF));
}

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

struct hsr_frame_info;
struct hsr_node;

struct hsr_proto_ops {
        /* format and send supervision frame */
        void (*send_sv_frame)(struct hsr_port *port, unsigned long *interval);
        void (*handle_san_frame)(bool san, enum hsr_port_type port,
                                 struct hsr_node *node);
        bool (*drop_frame)(struct hsr_frame_info *frame, struct hsr_port *port);
        struct sk_buff * (*get_untagged_frame)(struct hsr_frame_info *frame,
                                               struct hsr_port *port);
        struct sk_buff * (*create_tagged_frame)(struct hsr_frame_info *frame,
                                                struct hsr_port *port);
        int (*fill_frame_info)(__be16 proto, struct sk_buff *skb,
                               struct hsr_frame_info *frame);
        bool (*invalid_dan_ingress_frame)(__be16 protocol);
        void (*update_san_info)(struct hsr_node *node, bool is_sup);
};

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 */
        enum hsr_version prot_version;  /* Indicate if HSRv0, HSRv1 or PRPv1 */
        spinlock_t seqnr_lock;  /* locking for sequence_nr */
        spinlock_t list_lock;   /* locking for node list */
        struct hsr_proto_ops    *proto_ops;
#define PRP_LAN_ID      0x5     /* 0x1010 for A and 0x1011 for B. Bit 0 is set
                                 * based on SLAVE_A or SLAVE_B
                                 */
        u8 net_id;              /* for PRP, it occupies most significant 3 bits
                                 * of lan_id
                                 */
        unsigned char           sup_multicast_addr[ETH_ALEN] __aligned(sizeof(u16));
                                /* Align to u16 boundary to avoid unaligned access
                                 * in ether_addr_equal
                                 */
#ifdef  CONFIG_DEBUG_FS
        struct dentry *node_tbl_root;
#endif
};

#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);
}

static inline struct prp_rct *skb_get_PRP_rct(struct sk_buff *skb)
{
        unsigned char *tail = skb_tail_pointer(skb) - HSR_HLEN;

        struct prp_rct *rct = (struct prp_rct *)tail;

        if (rct->PRP_suffix == htons(ETH_P_PRP))
                return rct;

        return NULL;
}

/* Assume caller has confirmed this skb is PRP suffixed */
static inline u16 prp_get_skb_sequence_nr(struct prp_rct *rct)
{
        return ntohs(rct->sequence_nr);
}

static inline u16 get_prp_lan_id(struct prp_rct *rct)
{
        return ntohs(rct->lan_id_and_LSDU_size) >> 12;
}

/* assume there is a valid rct */
static inline bool prp_check_lsdu_size(struct sk_buff *skb,
                                       struct prp_rct *rct,
                                       bool is_sup)
{
        struct ethhdr *ethhdr;
        int expected_lsdu_size;

        if (is_sup) {
                expected_lsdu_size = HSR_V1_SUP_LSDUSIZE;
        } else {
                ethhdr = (struct ethhdr *)skb_mac_header(skb);
                expected_lsdu_size = skb->len - 14;
                if (ethhdr->h_proto == htons(ETH_P_8021Q))
                        expected_lsdu_size -= 4;
        }

        return (expected_lsdu_size == get_prp_LSDU_size(rct));
}

#if IS_ENABLED(CONFIG_DEBUG_FS)
void hsr_debugfs_rename(struct net_device *dev);
void hsr_debugfs_init(struct hsr_priv *priv, struct net_device *hsr_dev);
void hsr_debugfs_term(struct hsr_priv *priv);
void hsr_debugfs_create_root(void);
void hsr_debugfs_remove_root(void);
#else
static inline void hsr_debugfs_rename(struct net_device *dev)
{
}
static inline void hsr_debugfs_init(struct hsr_priv *priv,
                                    struct net_device *hsr_dev)
{}
static inline void hsr_debugfs_term(struct hsr_priv *priv)
{}
static inline void hsr_debugfs_create_root(void)
{}
static inline void hsr_debugfs_remove_root(void)
{}
#endif

#endif /*  __HSR_PRIVATE_H */