text: /* keys.c - Bluetooth key handling */
  
  /*
   * Copyright (c) 2015-2016 Intel Corporation
   *
   * SPDX-License-Identifier: Apache-2.0
   */
  
  #include <zephyr.h>
  #include <string.h>
  #include <stdlib.h>
  #include <atomic.h>
  #include <misc/util.h>
  
  #include <bluetooth.h>
  #include <conn.h>
  #include <hci_host.h>
  
  #define BT_DBG_ENABLED IS_ENABLED(CONFIG_BT_DEBUG_KEYS)
  #include "log.h"
  
  #include "rpa.h"
  #include "gatt_internal.h"
  #include "hci_core.h"
  #include "smp.h"
  #include "settings.h"
  #include "keys.h"
  #if defined(BFLB_BLE)
  #if defined(CONFIG_BT_SETTINGS)
  #include "easyflash.h"
  #endif
  #endif
  
  static struct bt_keys key_pool[CONFIG_BT_MAX_PAIRED];
  
  #define BT_KEYS_STORAGE_LEN_COMPAT (BT_KEYS_STORAGE_LEN - sizeof(uint32_t))
  
  #if IS_ENABLED(CONFIG_BT_KEYS_OVERWRITE_OLDEST)
  static u32_t aging_counter_val;
  static struct bt_keys *last_keys_updated;
  #endif /* CONFIG_BT_KEYS_OVERWRITE_OLDEST */
  
  struct bt_keys *bt_keys_get_addr(u8_t id, const bt_addr_le_t *addr)
  {
      struct bt_keys *keys;
      int i;
      size_t first_free_slot = ARRAY_SIZE(key_pool);
  
      BT_DBG("%s", bt_addr_le_str(addr));
  
      for (i = 0; i < ARRAY_SIZE(key_pool); i++) {
          keys = &key_pool[i];
  
          if (keys->id == id && !bt_addr_le_cmp(&keys->addr, addr)) {
              return keys;
          }
  
          if (first_free_slot == ARRAY_SIZE(key_pool) &&
              (!bt_addr_le_cmp(&keys->addr, BT_ADDR_LE_ANY) ||
               !keys->enc_size)) {
              first_free_slot = i;
          }
      }
  
  #if IS_ENABLED(CONFIG_BT_KEYS_OVERWRITE_OLDEST)
      if (first_free_slot == ARRAY_SIZE(key_pool)) {
          struct bt_keys *oldest = &key_pool[0];
  
          for (i = 1; i < ARRAY_SIZE(key_pool); i++) {
              struct bt_keys *current = &key_pool[i];
  
              if (current->aging_counter < oldest->aging_counter) {
                  oldest = current;
              }
          }
  
          bt_unpair(oldest->id, &oldest->addr);
          if (!bt_addr_le_cmp(&oldest->addr, BT_ADDR_LE_ANY)) {
              first_free_slot = oldest - &key_pool[0];
          }
      }
  
  #endif  /* CONFIG_BT_KEYS_OVERWRITE_OLDEST */
      if (first_free_slot < ARRAY_SIZE(key_pool)) {
          keys = &key_pool[first_free_slot];
          keys->id = id;
          bt_addr_le_copy(&keys->addr, addr);
  #if IS_ENABLED(CONFIG_BT_KEYS_OVERWRITE_OLDEST)
          keys->aging_counter = ++aging_counter_val;
          last_keys_updated = keys;
  #endif  /* CONFIG_BT_KEYS_OVERWRITE_OLDEST */
          BT_DBG("created %p for %s", keys, bt_addr_le_str(addr));
          return keys;
      }
  
      BT_DBG("unable to create keys for %s", bt_addr_le_str(addr));
  
      return NULL;
  }
  
  void bt_foreach_bond(u8_t id, void (*func)(const struct bt_bond_info *info,
                         void *user_data),
               void *user_data)
  {
      int i;
  
      for (i = 0; i < ARRAY_SIZE(key_pool); i++) {
          struct bt_keys *keys = &key_pool[i];
  
          if (keys->keys && keys->id == id) {
              struct bt_bond_info info;
  
              bt_addr_le_copy(&info.addr, &keys->addr);
              func(&info, user_data);
          }
      }
  }
  
  void bt_keys_foreach(int type, void (*func)(struct bt_keys *keys, void *data),
               void *data)
  {
      int i;
  
      for (i = 0; i < ARRAY_SIZE(key_pool); i++) {
          if ((key_pool[i].keys & type)) {
              func(&key_pool[i], data);
          }
      }
  }
  
  struct bt_keys *bt_keys_find(int type, u8_t id, const bt_addr_le_t *addr)
  {
      int i;
  
      BT_DBG("type %d %s", type, bt_addr_le_str(addr));
  
      for (i = 0; i < ARRAY_SIZE(key_pool); i++) {
          if ((key_pool[i].keys & type) && key_pool[i].id == id &&
              !bt_addr_le_cmp(&key_pool[i].addr, addr)) {
              return &key_pool[i];
          }
      }
  
      return NULL;
  }
  
  struct bt_keys *bt_keys_get_type(int type, u8_t id, const bt_addr_le_t *addr)
  {
      struct bt_keys *keys;
  
      BT_DBG("type %d %s", type, bt_addr_le_str(addr));
  
      keys = bt_keys_find(type, id, addr);
      if (keys) {
          return keys;
      }
  
      keys = bt_keys_get_addr(id, addr);
      if (!keys) {
          return NULL;
      }
  
      bt_keys_add_type(keys, type);
  
      return keys;
  }
  
  struct bt_keys *bt_keys_find_irk(u8_t id, const bt_addr_le_t *addr)
  {
      int i;
  
      BT_DBG("%s", bt_addr_le_str(addr));
  
      if (!bt_addr_le_is_rpa(addr)) {
          return NULL;
      }
  
      for (i = 0; i < ARRAY_SIZE(key_pool); i++) {
          if (!(key_pool[i].keys & BT_KEYS_IRK)) {
              continue;
          }
  
          if (key_pool[i].id == id &&
              !bt_addr_cmp(&addr->a, &key_pool[i].irk.rpa)) {
              BT_DBG("cached RPA %s for %s",
                     bt_addr_str(&key_pool[i].irk.rpa),
                     bt_addr_le_str(&key_pool[i].addr));
              return &key_pool[i];
          }
      }
  
      for (i = 0; i < ARRAY_SIZE(key_pool); i++) {
          if (!(key_pool[i].keys & BT_KEYS_IRK)) {
              continue;
          }
  
          if (key_pool[i].id != id) {
              continue;
          }
  
          if (bt_rpa_irk_matches(key_pool[i].irk.val, &addr->a)) {
              BT_DBG("RPA %s matches %s",
                     bt_addr_str(&key_pool[i].irk.rpa),
                     bt_addr_le_str(&key_pool[i].addr));
  
              bt_addr_copy(&key_pool[i].irk.rpa, &addr->a);
  
              return &key_pool[i];
          }
      }
  
      BT_DBG("No IRK for %s", bt_addr_le_str(addr));
  
      return NULL;
  }
  
  struct bt_keys *bt_keys_find_addr(u8_t id, const bt_addr_le_t *addr)
  {
      int i;
  
      BT_DBG("%s", bt_addr_le_str(addr));
  
      for (i = 0; i < ARRAY_SIZE(key_pool); i++) {
          if (key_pool[i].id == id &&
              !bt_addr_le_cmp(&key_pool[i].addr, addr)) {
              return &key_pool[i];
          }
      }
  
      return NULL;
  }
  
  void bt_keys_add_type(struct bt_keys *keys, int type)
  {
      keys->keys |= type;
  }
  
  void bt_keys_clear(struct bt_keys *keys)
  {
  #if defined(BFLB_BLE)
      if (keys->keys & BT_KEYS_IRK) {
          bt_id_del(keys);
      }
  
      memset(keys, 0, sizeof(*keys));
  
      #if defined (CONFIG_BT_SETTINGS)
      ef_del_env(NV_KEY_POOL);
      #endif
  #else
      BT_DBG("%s (keys 0x%04x)", bt_addr_le_str(&keys->addr), keys->keys);
  
      if (keys->keys & BT_KEYS_IRK) {
          bt_id_del(keys);
      }
  
      if (IS_ENABLED(CONFIG_BT_SETTINGS)) {
          char key[BT_SETTINGS_KEY_MAX];
  
          /* Delete stored keys from flash */
          if (keys->id) {
              char id[4];
  
              u8_to_dec(id, sizeof(id), keys->id);
              bt_settings_encode_key(key, sizeof(key), "keys",
                             &keys->addr, id);
          } else {
              bt_settings_encode_key(key, sizeof(key), "keys",
                             &keys->addr, NULL);
          }
  
          BT_DBG("Deleting key %s", log_strdup(key));
          settings_delete(key);
      }
  
      (void)memset(keys, 0, sizeof(*keys));
   #endif
  }
  
  static void keys_clear_id(struct bt_keys *keys, void *data)
  {
      u8_t *id = data;
  
      if (*id == keys->id) {
          if (IS_ENABLED(CONFIG_BT_SETTINGS)) {
              bt_gatt_clear(*id, &keys->addr);
          }
  
          bt_keys_clear(keys);
      }
  }
  
  void bt_keys_clear_all(u8_t id)
  {
      bt_keys_foreach(BT_KEYS_ALL, keys_clear_id, &id);
  }
  
  #if defined(CONFIG_BT_SETTINGS)
  int bt_keys_store(struct bt_keys *keys)
  {
  #if defined(BFLB_BLE)
      int err;
      err = bt_settings_set_bin(NV_KEY_POOL, (const u8_t *)&key_pool[0], sizeof(key_pool));
      return err;
  #else
      char val[BT_SETTINGS_SIZE(BT_KEYS_STORAGE_LEN)];
      char key[BT_SETTINGS_KEY_MAX];
      char *str;
      int err;
  
      str = settings_str_from_bytes(keys->storage_start, BT_KEYS_STORAGE_LEN,
                        val, sizeof(val));
      if (!str) {
          BT_ERR("Unable to encode bt_keys as value");
          return -EINVAL;
      }
  
      if (keys->id) {
          char id[4];
  
          u8_to_dec(id, sizeof(id), keys->id);
          bt_settings_encode_key(key, sizeof(key), "keys", &keys->addr,
                         id);
      } else {
          bt_settings_encode_key(key, sizeof(key), "keys", &keys->addr,
                         NULL);
      }
  
      err = settings_save_one(key, keys->storage_start, BT_KEYS_STORAGE_LEN);
      if (err) {
          BT_ERR("Failed to save keys (err %d)", err);
          return err;
      }
  
      BT_DBG("Stored keys for %s (%s)", bt_addr_le_str(&keys->addr),
             log_strdup(key));
  
      return 0;
   #endif //BFLB_BLE
  }
  
  #if !defined(BFLB_BLE)
  static int keys_set(const char *name, size_t len_rd, settings_read_cb read_cb,
              void *cb_arg)
  {
      struct bt_keys *keys;
      bt_addr_le_t addr;
      u8_t id;
      size_t len;
      int err;
      char val[BT_KEYS_STORAGE_LEN];
      const char *next;
  
      if (!name) {
          BT_ERR("Insufficient number of arguments");
          return -EINVAL;
      }
  
      len = read_cb(cb_arg, val, sizeof(val));
      if (len < 0) {
          BT_ERR("Failed to read value (err %zu)", len);
          return -EINVAL;
      }
  
      BT_DBG("name %s val %s", log_strdup(name),
             (len) ? bt_hex(val, sizeof(val)) : "(null)");
  
      err = bt_settings_decode_key(name, &addr);
      if (err) {
          BT_ERR("Unable to decode address %s", name);
          return -EINVAL;
      }
  
      settings_name_next(name, &next);
  
      if (!next) {
          id = BT_ID_DEFAULT;
      } else {
          id = strtol(next, NULL, 10);
      }
  
      if (!len) {
          keys = bt_keys_find(BT_KEYS_ALL, id, &addr);
          if (keys) {
              (void)memset(keys, 0, sizeof(*keys));
              BT_DBG("Cleared keys for %s", bt_addr_le_str(&addr));
          } else {
              BT_WARN("Unable to find deleted keys for %s",
                  bt_addr_le_str(&addr));
          }
  
          return 0;
      }
  
      keys = bt_keys_get_addr(id, &addr);
      if (!keys) {
          BT_ERR("Failed to allocate keys for %s", bt_addr_le_str(&addr));
          return -ENOMEM;
      }
      if (len != BT_KEYS_STORAGE_LEN) {
          do {
              /* Load shorter structure for compatibility with old
               * records format with no counter.
               */
              if (IS_ENABLED(CONFIG_BT_KEYS_OVERWRITE_OLDEST) &&
                  len == BT_KEYS_STORAGE_LEN_COMPAT) {
                  BT_WARN("Keys for %s have no aging counter",
                      bt_addr_le_str(&addr));
                  memcpy(keys->storage_start, val, len);
                  continue;
              }
  
              BT_ERR("Invalid key length %zu != %zu", len,
                     BT_KEYS_STORAGE_LEN);
              bt_keys_clear(keys);
  
              return -EINVAL;
          } while (0);
      } else {
          memcpy(keys->storage_start, val, len);
      }
  
      BT_DBG("Successfully restored keys for %s", bt_addr_le_str(&addr));
  #if IS_ENABLED(CONFIG_BT_KEYS_OVERWRITE_OLDEST)
      if (aging_counter_val < keys->aging_counter) {
          aging_counter_val = keys->aging_counter;
      }
  #endif  /* CONFIG_BT_KEYS_OVERWRITE_OLDEST */
      return 0;
  }
  #endif //!(BFLB_BLE)
  
  static void id_add(struct bt_keys *keys, void *user_data)
  {
      bt_id_add(keys);
  }
  
  #if defined(BFLB_BLE)
  int keys_commit(void)
  #else
  static int keys_commit(void)
  #endif
  {
      BT_DBG("");
  
      /* We do this in commit() rather than add() since add() may get
       * called multiple times for the same address, especially if
       * the keys were already removed.
       */
      bt_keys_foreach(BT_KEYS_IRK, id_add, NULL);
  
      return 0;
  }
  
  //SETTINGS_STATIC_HANDLER_DEFINE(bt_keys, "bt/keys", NULL, keys_set, keys_commit,
  //                 NULL);
  
  #if defined(BFLB_BLE)
  int bt_keys_load(void)
  {
      return bt_settings_get_bin(NV_KEY_POOL, (u8_t *)&key_pool[0], sizeof(key_pool), NULL);
  }
  #endif
  
  #endif /* CONFIG_BT_SETTINGS */
  
  #if IS_ENABLED(CONFIG_BT_KEYS_OVERWRITE_OLDEST)
  void bt_keys_update_usage(u8_t id, const bt_addr_le_t *addr)
  {
      struct bt_keys *keys = bt_keys_find_addr(id, addr);
  
      if (!keys) {
          return;
      }
  
      if (last_keys_updated == keys) {
          return;
      }
  
      keys->aging_counter = ++aging_counter_val;
      last_keys_updated = keys;
  
      BT_DBG("Aging counter for %s is set to %u", bt_addr_le_str(addr),
             keys->aging_counter);
  
      if (IS_ENABLED(CONFIG_BT_KEYS_SAVE_AGING_COUNTER_ON_PAIRING)) {
          bt_keys_store(keys);
      }
  }
  
  #endif  /* CONFIG_BT_KEYS_OVERWRITE_OLDEST */
  