text: /** @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. */
  
    BT_CONN_AUTO_PHY_COMPLETE, /* Auto-initiated PHY procedure done */
    BT_CONN_AUTO_FEATURE_EXCH, /* Auto-initiated LE Feat done */
    BT_CONN_AUTO_VERSION_INFO, /* Auto-initiated LE version done */
  
    /* 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_STACK_PTS)
    u8_t own_adder_type;
  #endif
  };
  
  #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 {
    sys_snode_t node;
  
    bt_conn_tx_cb_t cb;
    void *user_data;
  
    /* Number of pending packets without a callback after this one */
    u32_t pending_no_cb;
  };
  
  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 with a callback */
    sys_slist_t tx_pending;
    /* Sent but not acknowledged TX packets without a callback before
     * the next packet (if any) in tx_pending.
     */
    u32_t pending_no_cb;
  
    /* Completed TX for which we need to call the callback */
    sys_slist_t tx_complete;
    struct k_work tx_complete_work;
  
    /* 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
    };
  
  #if defined(CONFIG_BT_REMOTE_VERSION)
    struct bt_conn_rv {
      u8_t version;
      u16_t manufacturer;
      u16_t subversion;
    } rv;
  #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_remote_info(struct bt_conn *conn);
  
  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 */
  #if defined(CONFIG_NET_BUF_LOG)
  struct net_buf *bt_conn_create_pdu_timeout_debug(struct net_buf_pool *pool,
                                                   size_t reserve, s32_t timeout,
                                                   const char *func, int line);
  #define bt_conn_create_pdu_timeout(_pool, _reserve, _timeout)                  \
    bt_conn_create_pdu_timeout_debug(_pool, _reserve, _timeout, __func__,        \
                                     __LINE__)
  
  #define bt_conn_create_pdu(_pool, _reserve)                                    \
    bt_conn_create_pdu_timeout_debug(_pool, _reserve, K_FOREVER, __func__,       \
                                     __line__)
  #else
  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)
  #endif
  
  /* Prepare a PDU to be sent over a connection */
  #if defined(CONFIG_NET_BUF_LOG)
  struct net_buf *bt_conn_create_frag_timeout_debug(size_t reserve, s32_t timeout,
                                                    const char *func, int line);
  
  #define bt_conn_create_frag_timeout(_reserve, _timeout)                        \
    bt_conn_create_frag_timeout_debug(_reserve, _timeout, __func__, __LINE__)
  
  #define bt_conn_create_frag(_reserve)                                          \
    bt_conn_create_frag_timeout_debug(_reserve, K_FOREVER, __func__, __LINE__)
  #else
  struct net_buf *bt_conn_create_frag_timeout(size_t reserve, s32_t timeout);
  
  #define bt_conn_create_frag(_reserve)                                          \
    bt_conn_create_frag_timeout(_reserve, K_FOREVER)
  #endif
  
  /* 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);
  
  #if defined(BFLB_BLE)
  /** @brief Get connection handle for a connection.
   *
   * @param conn Connection object.
   * @param conn_handle Place to store the Connection handle.
   *
   * @return 0 on success or negative error value on failure.
   */
  int bt_hci_get_conn_handle(const struct bt_conn *conn, u16_t *conn_handle);
  #endif
  