/** @file
 *  @brief Internal APIs for Bluetooth connection handling.
 */

/*
 * Copyright (c) 2015 Intel Corporation
 *
 * SPDX-License-Identifier: Apache-2.0
 */
typedef enum __packed {
	BT_CONN_DISCONNECTED,
	BT_CONN_CONNECT_SCAN,
	BT_CONN_CONNECT_DIR_ADV,
	BT_CONN_CONNECT,
	BT_CONN_CONNECTED,
	BT_CONN_DISCONNECT,
} bt_conn_state_t;

/* bt_conn flags: the flags defined here represent connection parameters */
enum {
	BT_CONN_AUTO_CONNECT,
	BT_CONN_BR_LEGACY_SECURE,	/* 16 digits legacy PIN tracker */
	BT_CONN_USER,			/* user I/O when pairing */
	BT_CONN_BR_PAIRING,		/* BR connection in pairing context */
	BT_CONN_BR_NOBOND,		/* SSP no bond pairing tracker */
	BT_CONN_BR_PAIRING_INITIATOR,	/* local host starts authentication */
	BT_CONN_CLEANUP,                /* Disconnected, pending cleanup */
	BT_CONN_AUTO_PHY_UPDATE,        /* Auto-update PHY */
	BT_CONN_SLAVE_PARAM_UPDATE,	/* If slave param update timer fired */
	BT_CONN_SLAVE_PARAM_SET,	/* If slave param were set from app */
	BT_CONN_SLAVE_PARAM_L2CAP,	/* If should force L2CAP for CPUP */
	BT_CONN_FORCE_PAIR,             /* Pairing even with existing keys. */

	/* Total number of flags - must be at the end of the enum */
	BT_CONN_NUM_FLAGS,
};

struct bt_conn_le {
	bt_addr_le_t		dst;

	bt_addr_le_t		init_addr;
	bt_addr_le_t		resp_addr;

	u16_t			interval;
	u16_t			interval_min;
	u16_t			interval_max;

	u16_t			latency;
	u16_t			timeout;
	u16_t			pending_latency;
	u16_t			pending_timeout;

	u8_t			features[8];

	struct bt_keys		*keys;
};

#if defined(CONFIG_BT_BREDR)
/* For now reserve space for 2 pages of LMP remote features */
#define LMP_MAX_PAGES 2

struct bt_conn_br {
	bt_addr_t		dst;
	u8_t			remote_io_capa;
	u8_t			remote_auth;
	u8_t			pairing_method;
	/* remote LMP features pages per 8 bytes each */
	u8_t			features[LMP_MAX_PAGES][8];

	struct bt_keys_link_key	*link_key;
};

struct bt_conn_sco {
	/* Reference to ACL Connection */
	struct bt_conn          *acl;
	u16_t                pkt_type;
};
#endif

typedef void (*bt_conn_tx_cb_t)(struct bt_conn *conn, void *user_data);

struct bt_conn_tx_data {
	bt_conn_tx_cb_t cb;
	void *user_data;
};

struct bt_conn_tx {
	sys_snode_t node;
	struct bt_conn *conn;
	struct k_work work;
	struct bt_conn_tx_data data;
};

struct bt_conn {
	u16_t			handle;
	u8_t			type;
	u8_t			role;

	ATOMIC_DEFINE(flags, BT_CONN_NUM_FLAGS);

	/* Which local identity address this connection uses */
	u8_t                    id;

#if defined(CONFIG_BT_SMP) || defined(CONFIG_BT_BREDR)
	bt_security_t		sec_level;
	bt_security_t		required_sec_level;
	u8_t			encrypt;
#endif /* CONFIG_BT_SMP || CONFIG_BT_BREDR */

	/* Connection error or reason for disconnect */
	u8_t			err;

	bt_conn_state_t		state;

	u16_t		        rx_len;
	struct net_buf		*rx;

	/* Sent but not acknowledged TX packets */
	sys_slist_t		tx_pending;
	/* Acknowledged but not yet notified TX packets */
	struct k_fifo		tx_notify;

	/* Queue for outgoing ACL data */
	struct k_fifo		tx_queue;

	/* Active L2CAP channels */
	sys_slist_t		channels;

	atomic_t		ref;

	/* Delayed work for connection update and other deferred tasks */
	struct k_delayed_work	update_work;

	union {
		struct bt_conn_le	le;
#if defined(CONFIG_BT_BREDR)
		struct bt_conn_br	br;
		struct bt_conn_sco	sco;
#endif
	};
};

/* Process incoming data for a connection */
void bt_conn_recv(struct bt_conn *conn, struct net_buf *buf, u8_t flags);

/* Send data over a connection */
int bt_conn_send_cb(struct bt_conn *conn, struct net_buf *buf,
		    bt_conn_tx_cb_t cb, void *user_data);

static inline int bt_conn_send(struct bt_conn *conn, struct net_buf *buf)
{
	return bt_conn_send_cb(conn, buf, NULL, NULL);
}

/* Add a new LE connection */
struct bt_conn *bt_conn_add_le(u8_t id, const bt_addr_le_t *peer);

/* Add a new BR/EDR connection */
struct bt_conn *bt_conn_add_br(const bt_addr_t *peer);

/* Add a new SCO connection */
struct bt_conn *bt_conn_add_sco(const bt_addr_t *peer, int link_type);

/* Cleanup SCO references */
void bt_sco_cleanup(struct bt_conn *sco_conn);

/* Look up an existing sco connection by BT address */
struct bt_conn *bt_conn_lookup_addr_sco(const bt_addr_t *peer);

/* Look up an existing connection by BT address */
struct bt_conn *bt_conn_lookup_addr_br(const bt_addr_t *peer);

void bt_conn_pin_code_req(struct bt_conn *conn);
u8_t bt_conn_get_io_capa(void);
u8_t bt_conn_ssp_get_auth(const struct bt_conn *conn);
void bt_conn_ssp_auth(struct bt_conn *conn, u32_t passkey);
void bt_conn_ssp_auth_complete(struct bt_conn *conn, u8_t status);

void bt_conn_disconnect_all(u8_t id);

/* Look up an existing connection */
struct bt_conn *bt_conn_lookup_handle(u16_t handle);

/* Compare an address with bt_conn destination address */
int bt_conn_addr_le_cmp(const struct bt_conn *conn, const bt_addr_le_t *peer);


/* Helpers for identifying & looking up connections based on the the index to
 * the connection list. This is useful for O(1) lookups, but can't be used
 * e.g. as the handle since that's assigned to us by the controller.
 */
#define BT_CONN_ID_INVALID 0xff
struct bt_conn *bt_conn_lookup_id(u8_t id);

/* Look up a connection state. For BT_ADDR_LE_ANY, returns the first connection
 * with the specific state
 */
struct bt_conn *bt_conn_lookup_state_le(const bt_addr_le_t *peer,
					const bt_conn_state_t state);

/* Set connection object in certain state and perform action related to state */
void bt_conn_set_state(struct bt_conn *conn, bt_conn_state_t state);

int bt_conn_le_conn_update(struct bt_conn *conn,
			   const struct bt_le_conn_param *param);

void notify_le_param_updated(struct bt_conn *conn);

bool le_param_req(struct bt_conn *conn, struct bt_le_conn_param *param);

#if defined(CONFIG_BT_SMP)
/* rand and ediv should be in BT order */
int bt_conn_le_start_encryption(struct bt_conn *conn, u8_t rand[8],
				u8_t ediv[2], const u8_t *ltk, size_t len);

/* Notify higher layers that RPA was resolved */
void bt_conn_identity_resolved(struct bt_conn *conn);
#endif /* CONFIG_BT_SMP */

#if defined(CONFIG_BT_SMP) || defined(CONFIG_BT_BREDR)
/* Notify higher layers that connection security changed */
void bt_conn_security_changed(struct bt_conn *conn, enum bt_security_err err);
#endif /* CONFIG_BT_SMP || CONFIG_BT_BREDR */

/* Prepare a PDU to be sent over a connection */
struct net_buf *bt_conn_create_pdu_timeout(struct net_buf_pool *pool,
					   size_t reserve, s32_t timeout);

#define bt_conn_create_pdu(_pool, _reserve) \
	bt_conn_create_pdu_timeout(_pool, _reserve, K_FOREVER)

/* Initialize connection management */
int bt_conn_init(void);

/* Selects based on connecton type right semaphore for ACL packets */
struct k_sem *bt_conn_get_pkts(struct bt_conn *conn);

/* k_poll related helpers for the TX thread */
int bt_conn_prepare_events(struct k_poll_event events[]);
void bt_conn_process_tx(struct bt_conn *conn);
void bt_conn_notify_tx(struct bt_conn *conn);