bgscan_simple.c 3.5 KB

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  1. /*
  2. * WPA Supplicant - background scan and roaming module: simple
  3. * Copyright (c) 2009, Jouni Malinen <j@w1.fi>
  4. *
  5. * This program is free software; you can redistribute it and/or modify
  6. * it under the terms of the GNU General Public License version 2 as
  7. * published by the Free Software Foundation.
  8. *
  9. * Alternatively, this software may be distributed under the terms of BSD
  10. * license.
  11. *
  12. * See README and COPYING for more details.
  13. */
  14. #include "includes.h"
  15. #include "common.h"
  16. #include "eloop.h"
  17. #include "drivers/driver.h"
  18. #include "config_ssid.h"
  19. #include "wpa_supplicant_i.h"
  20. #include "scan.h"
  21. #include "bgscan.h"
  22. struct bgscan_simple_data {
  23. struct wpa_supplicant *wpa_s;
  24. const struct wpa_ssid *ssid;
  25. int scan_interval;
  26. };
  27. static void bgscan_simple_timeout(void *eloop_ctx, void *timeout_ctx)
  28. {
  29. struct bgscan_simple_data *data = eloop_ctx;
  30. struct wpa_supplicant *wpa_s = data->wpa_s;
  31. struct wpa_driver_scan_params params;
  32. os_memset(&params, 0, sizeof(params));
  33. params.num_ssids = 1;
  34. params.ssids[0].ssid = data->ssid->ssid;
  35. params.ssids[0].ssid_len = data->ssid->ssid_len;
  36. params.freqs = data->ssid->scan_freq;
  37. /*
  38. * A more advanced bgscan module would learn about most like channels
  39. * over time and request scans only for some channels (probing others
  40. * every now and then) to reduce effect on the data connection.
  41. */
  42. wpa_printf(MSG_DEBUG, "bgscan simple: Request a background scan");
  43. if (wpa_supplicant_trigger_scan(wpa_s, &params)) {
  44. wpa_printf(MSG_DEBUG, "bgscan simple: Failed to trigger scan");
  45. eloop_register_timeout(data->scan_interval, 0,
  46. bgscan_simple_timeout, data, NULL);
  47. }
  48. }
  49. static void * bgscan_simple_init(struct wpa_supplicant *wpa_s,
  50. const char *params,
  51. const struct wpa_ssid *ssid)
  52. {
  53. struct bgscan_simple_data *data;
  54. data = os_zalloc(sizeof(*data));
  55. if (data == NULL)
  56. return NULL;
  57. data->wpa_s = wpa_s;
  58. data->ssid = ssid;
  59. if (params)
  60. data->scan_interval = atoi(params);
  61. if (data->scan_interval <= 0)
  62. data->scan_interval = 30;
  63. eloop_register_timeout(data->scan_interval, 0, bgscan_simple_timeout,
  64. data, NULL);
  65. return data;
  66. }
  67. static void bgscan_simple_deinit(void *priv)
  68. {
  69. struct bgscan_simple_data *data = priv;
  70. eloop_cancel_timeout(bgscan_simple_timeout, data, NULL);
  71. os_free(data);
  72. }
  73. static int bgscan_simple_notify_scan(void *priv)
  74. {
  75. struct bgscan_simple_data *data = priv;
  76. wpa_printf(MSG_DEBUG, "bgscan simple: scan result notification");
  77. eloop_cancel_timeout(bgscan_simple_timeout, data, NULL);
  78. eloop_register_timeout(data->scan_interval, 0, bgscan_simple_timeout,
  79. data, NULL);
  80. /*
  81. * A more advanced bgscan could process scan results internally, select
  82. * the BSS and request roam if needed. This sample uses the existing
  83. * BSS/ESS selection routine. Change this to return 1 if selection is
  84. * done inside the bgscan module.
  85. */
  86. return 0;
  87. }
  88. static void bgscan_simple_notify_beacon_loss(void *priv)
  89. {
  90. wpa_printf(MSG_DEBUG, "bgscan simple: beacon loss");
  91. /* TODO: speed up background scanning */
  92. }
  93. static void bgscan_simple_notify_signal_change(void *priv)
  94. {
  95. wpa_printf(MSG_DEBUG, "bgscan simple: signal level changed");
  96. /* TODO: if signal strength dropped enough, speed up background
  97. * scanning */
  98. }
  99. const struct bgscan_ops bgscan_simple_ops = {
  100. .name = "simple",
  101. .init = bgscan_simple_init,
  102. .deinit = bgscan_simple_deinit,
  103. .notify_scan = bgscan_simple_notify_scan,
  104. .notify_beacon_loss = bgscan_simple_notify_beacon_loss,
  105. .notify_signal_change = bgscan_simple_notify_signal_change,
  106. };