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authorJouni Malinen <j@w1.fi>2009-12-27 19:07:47 (GMT)
committerJouni Malinen <j@w1.fi>2009-12-27 19:07:47 (GMT)
commit83922c2d344eb7fb77387bc0253449524e949901 (patch)
tree012abc38f8b34451ee67c4ae69cc117c05486d1c /wpa_supplicant/bss.c
parent60ad2c7befcaba3be072ab20368418a41dd828b9 (diff)
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Add BSS table to track scan results without dropping information
Collect information from scan results into a BSS table that will not expire information as quickly as scan results where every new scan, no matter for how limited set of channels/SSIDs, clears all old information. For now, this is only used for D-Bus BSS added/removed notifications, but this will likely be extended to be used internally instead of the scan results to better support partial scans.
Diffstat (limited to 'wpa_supplicant/bss.c')
-rw-r--r--wpa_supplicant/bss.c262
1 files changed, 262 insertions, 0 deletions
diff --git a/wpa_supplicant/bss.c b/wpa_supplicant/bss.c
new file mode 100644
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+++ b/wpa_supplicant/bss.c
@@ -0,0 +1,262 @@
+/*
+ * BSS table
+ * Copyright (c) 2009, Jouni Malinen <j@w1.fi>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * Alternatively, this software may be distributed under the terms of BSD
+ * license.
+ *
+ * See README and COPYING for more details.
+ */
+
+#include "utils/includes.h"
+
+#include "utils/common.h"
+#include "utils/eloop.h"
+#include "common/ieee802_11_defs.h"
+#include "drivers/driver.h"
+#include "wpa_supplicant_i.h"
+#include "notify.h"
+#include "bss.h"
+
+
+#ifndef WPA_BSS_MAX_COUNT
+#define WPA_BSS_MAX_COUNT 200
+#endif /* WPA_BSS_MAX_COUNT */
+
+/**
+ * WPA_BSS_EXPIRATION_PERIOD - Period of expiration run in seconds
+ */
+#define WPA_BSS_EXPIRATION_PERIOD 10
+
+/**
+ * WPA_BSS_EXPIRATION_AGE - BSS entry age after which it can be expired
+ *
+ * This value control the time in seconds after which a BSS entry gets removed
+ * if it has not been updated or is not in use.
+ */
+#define WPA_BSS_EXPIRATION_AGE 180
+
+/**
+ * WPA_BSS_EXPIRATION_SCAN_COUNT - Expire BSS after number of scans
+ *
+ * If the BSS entry has not been seen in this many scans, it will be removed.
+ * Value 1 means that the entry is removed after the first scan without the
+ * BSSID being seen. Larger values can be used to avoid BSS entries
+ * disappearing if they are not visible in every scan (e.g., low signal quality
+ * or interference).
+ */
+#define WPA_BSS_EXPIRATION_SCAN_COUNT 2
+
+
+static void wpa_bss_remove(struct wpa_supplicant *wpa_s, struct wpa_bss *bss)
+{
+ dl_list_del(&bss->list);
+ wpa_s->num_bss--;
+ wpa_printf(MSG_DEBUG, "BSS: Remove id %u BSSID " MACSTR " SSID '%s'",
+ bss->id, MAC2STR(bss->bssid),
+ wpa_ssid_txt(bss->ssid, bss->ssid_len));
+ wpas_notify_bss_removed(wpa_s, bss->bssid);
+ os_free(bss);
+}
+
+
+static struct wpa_bss * wpa_bss_get(struct wpa_supplicant *wpa_s,
+ const u8 *bssid, const u8 *ssid,
+ size_t ssid_len)
+{
+ struct wpa_bss *bss;
+ dl_list_for_each(bss, &wpa_s->bss, struct wpa_bss, list) {
+ if (os_memcmp(bss->bssid, bssid, ETH_ALEN) == 0 &&
+ bss->ssid_len == ssid_len &&
+ os_memcmp(bss->ssid, ssid, ssid_len) == 0)
+ return bss;
+ }
+ return NULL;
+}
+
+
+static void wpa_bss_copy_res(struct wpa_bss *dst, struct wpa_scan_res *src)
+{
+ os_time_t usec;
+
+ dst->flags = src->flags;
+ os_memcpy(dst->bssid, src->bssid, ETH_ALEN);
+ dst->freq = src->freq;
+ dst->beacon_int = src->beacon_int;
+ dst->caps = src->caps;
+ dst->qual = src->qual;
+ dst->noise = src->noise;
+ dst->level = src->level;
+ dst->tsf = src->tsf;
+
+ os_get_time(&dst->last_update);
+ dst->last_update.sec -= src->age / 1000;
+ usec = (src->age % 1000) * 1000;
+ if (dst->last_update.usec < usec) {
+ dst->last_update.sec--;
+ dst->last_update.usec += 1000000;
+ }
+ dst->last_update.usec -= usec;
+}
+
+
+static void wpa_bss_add(struct wpa_supplicant *wpa_s,
+ const u8 *ssid, size_t ssid_len,
+ struct wpa_scan_res *res)
+{
+ struct wpa_bss *bss;
+
+ bss = os_zalloc(sizeof(*bss) + res->ie_len);
+ if (bss == NULL)
+ return;
+ bss->id = wpa_s->bss_next_id++;
+ bss->last_update_idx = wpa_s->bss_update_idx;
+ wpa_bss_copy_res(bss, res);
+ os_memcpy(bss->ssid, ssid, ssid_len);
+ bss->ssid_len = ssid_len;
+ bss->ie_len = res->ie_len;
+ os_memcpy(bss + 1, res + 1, res->ie_len);
+
+ dl_list_add_tail(&wpa_s->bss, &bss->list);
+ wpa_s->num_bss++;
+ wpa_printf(MSG_DEBUG, "BSS: Add new id %u BSSID " MACSTR " SSID '%s'",
+ bss->id, MAC2STR(bss->bssid), wpa_ssid_txt(ssid, ssid_len));
+ wpas_notify_bss_added(wpa_s, res->bssid);
+ if (wpa_s->num_bss > WPA_BSS_MAX_COUNT) {
+ /* Remove the oldest entry */
+ wpa_bss_remove(wpa_s, dl_list_first(&wpa_s->bss,
+ struct wpa_bss, list));
+ }
+}
+
+
+static void wpa_bss_update(struct wpa_supplicant *wpa_s, struct wpa_bss *bss,
+ struct wpa_scan_res *res)
+{
+ bss->scan_miss_count = 0;
+ bss->last_update_idx = wpa_s->bss_update_idx;
+ wpa_bss_copy_res(bss, res);
+ /* Move the entry to the end of the list */
+ dl_list_del(&bss->list);
+ if (bss->ie_len >= res->ie_len) {
+ os_memcpy(bss + 1, res + 1, res->ie_len);
+ bss->ie_len = res->ie_len;
+ } else {
+ struct wpa_bss *nbss;
+ nbss = os_realloc(bss, sizeof(*bss) + res->ie_len);
+ if (nbss) {
+ bss = nbss;
+ os_memcpy(bss + 1, res + 1, res->ie_len);
+ bss->ie_len = res->ie_len;
+ }
+ }
+ dl_list_add_tail(&wpa_s->bss, &bss->list);
+}
+
+
+void wpa_bss_update_start(struct wpa_supplicant *wpa_s)
+{
+ wpa_s->bss_update_idx++;
+ wpa_printf(MSG_DEBUG, "BSS: Start scan result update %u",
+ wpa_s->bss_update_idx);
+}
+
+
+void wpa_bss_update_scan_res(struct wpa_supplicant *wpa_s,
+ struct wpa_scan_res *res)
+{
+ const u8 *ssid;
+ struct wpa_bss *bss;
+
+ ssid = wpa_scan_get_ie(res, WLAN_EID_SSID);
+ if (ssid == NULL) {
+ wpa_printf(MSG_DEBUG, "BSS: No SSID IE included for " MACSTR,
+ MAC2STR(res->bssid));
+ return;
+ }
+ if (ssid[1] > 32) {
+ wpa_printf(MSG_DEBUG, "BSS: Too long SSID IE included for "
+ MACSTR, MAC2STR(res->bssid));
+ return;
+ }
+
+ /* TODO: add option for ignoring BSSes we are not interested in
+ * (to save memory) */
+ bss = wpa_bss_get(wpa_s, res->bssid, ssid + 2, ssid[1]);
+ if (bss == NULL)
+ wpa_bss_add(wpa_s, ssid + 2, ssid[1], res);
+ else
+ wpa_bss_update(wpa_s, bss, res);
+}
+
+
+void wpa_bss_update_end(struct wpa_supplicant *wpa_s)
+{
+ struct wpa_bss *bss, *n;
+
+ /* TODO: expire only entries that were on the scanned frequencies/SSIDs
+ * list; need to get info from driver about scanned frequencies and
+ * SSIDs to be able to figure out which entries should be expired based
+ * on this */
+
+ dl_list_for_each_safe(bss, n, &wpa_s->bss, struct wpa_bss, list) {
+ if (bss->last_update_idx < wpa_s->bss_update_idx)
+ bss->scan_miss_count++;
+ if (bss->scan_miss_count >= WPA_BSS_EXPIRATION_SCAN_COUNT) {
+ wpa_printf(MSG_DEBUG, "BSS: Expire BSS %u due to no "
+ "match in scan", bss->id);
+ wpa_bss_remove(wpa_s, bss);
+ }
+ }
+}
+
+
+static void wpa_bss_timeout(void *eloop_ctx, void *timeout_ctx)
+{
+ struct wpa_supplicant *wpa_s = eloop_ctx;
+ struct wpa_bss *bss, *n;
+ struct os_time t;
+
+ if (dl_list_empty(&wpa_s->bss))
+ return;
+
+ os_get_time(&t);
+ t.sec -= WPA_BSS_EXPIRATION_AGE;
+
+ dl_list_for_each_safe(bss, n, &wpa_s->bss, struct wpa_bss, list) {
+ if (os_memcmp(bss->bssid, wpa_s->bssid, ETH_ALEN) == 0 ||
+ os_memcmp(bss->bssid, wpa_s->pending_bssid, ETH_ALEN) == 0)
+ continue; /* do not expire BSSes that are in use */
+
+ if (os_time_before(&bss->last_update, &t)) {
+ wpa_printf(MSG_DEBUG, "BSS: Expire BSS %u due to age",
+ bss->id);
+ wpa_bss_remove(wpa_s, bss);
+ } else
+ break;
+ }
+ eloop_register_timeout(WPA_BSS_EXPIRATION_PERIOD, 0,
+ wpa_bss_timeout, wpa_s, NULL);
+}
+
+
+int wpa_bss_init(struct wpa_supplicant *wpa_s)
+{
+ dl_list_init(&wpa_s->bss);
+ eloop_register_timeout(WPA_BSS_EXPIRATION_PERIOD, 0,
+ wpa_bss_timeout, wpa_s, NULL);
+ return 0;
+}
+
+
+void wpa_bss_deinit(struct wpa_supplicant *wpa_s)
+{
+ struct wpa_bss *bss, *n;
+ eloop_cancel_timeout(wpa_bss_timeout, wpa_s, NULL);
+ dl_list_for_each_safe(bss, n, &wpa_s->bss, struct wpa_bss, list)
+ wpa_bss_remove(wpa_s, bss);
+}