WNM: Fetch scan results before checking transition candidates
On receiving a WNM BSS Transition Management Request frame with a candidate list, fetch the latest scan results from the kernel to see if there are any recent scan results for the candidates and initiate a connection if found. This helps to avoid triggering a new scan in cases where a scan initiated by something else (e.g., an internal beacon measurement report functionality in a driver) has processed Beacon or Probe Response frames without wpa_supplicant having received a notification of such an update yet. Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>
This commit is contained in:
Kanchanapally, Vidyullatha
Jouni Malinen
parent
49ae6ddbca
commit
2f195639ec
3 changed files with 151 additions and 26 deletions
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@ -1875,8 +1875,8 @@ int wpa_supplicant_filter_bssid_match(struct wpa_supplicant *wpa_s,
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}
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static void filter_scan_res(struct wpa_supplicant *wpa_s,
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struct wpa_scan_results *res)
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void filter_scan_res(struct wpa_supplicant *wpa_s,
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struct wpa_scan_results *res)
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{
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size_t i, j;
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@ -1909,7 +1909,7 @@ static void filter_scan_res(struct wpa_supplicant *wpa_s,
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#define DEFAULT_NOISE_FLOOR_2GHZ (-89)
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#define DEFAULT_NOISE_FLOOR_5GHZ (-92)
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static void scan_snr(struct wpa_scan_res *res)
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void scan_snr(struct wpa_scan_res *res)
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{
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if (res->flags & WPA_SCAN_NOISE_INVALID) {
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res->noise = IS_5GHZ(res->freq) ?
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@ -1993,8 +1993,8 @@ static unsigned int max_vht80_rate(int snr)
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}
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static void scan_est_throughput(struct wpa_supplicant *wpa_s,
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struct wpa_scan_res *res)
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void scan_est_throughput(struct wpa_supplicant *wpa_s,
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struct wpa_scan_res *res)
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{
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enum local_hw_capab capab = wpa_s->hw_capab;
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int rate; /* max legacy rate in 500 kb/s units */
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@ -51,5 +51,10 @@ int wpas_mac_addr_rand_scan_set(struct wpa_supplicant *wpa_s,
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unsigned int type, const u8 *addr,
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const u8 *mask);
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int wpas_abort_ongoing_scan(struct wpa_supplicant *wpa_s);
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void filter_scan_res(struct wpa_supplicant *wpa_s,
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struct wpa_scan_results *res);
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void scan_snr(struct wpa_scan_res *res);
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void scan_est_throughput(struct wpa_supplicant *wpa_s,
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struct wpa_scan_res *res);
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#endif /* SCAN_H */
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@ -24,6 +24,7 @@
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#define MAX_TFS_IE_LEN 1024
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#define WNM_MAX_NEIGHBOR_REPORT 10
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#define WNM_SCAN_RESULT_AGE 2 /* 2 seconds */
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/* get the TFS IE from driver */
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static int ieee80211_11_get_tfs_ie(struct wpa_supplicant *wpa_s, u8 *buf,
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@ -499,7 +500,7 @@ static void wnm_parse_neighbor_report(struct wpa_supplicant *wpa_s,
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static struct wpa_bss *
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compare_scan_neighbor_results(struct wpa_supplicant *wpa_s)
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compare_scan_neighbor_results(struct wpa_supplicant *wpa_s, os_time_t age_secs)
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{
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u8 i;
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@ -532,6 +533,19 @@ compare_scan_neighbor_results(struct wpa_supplicant *wpa_s)
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continue;
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}
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if (age_secs) {
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struct os_reltime now;
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if (os_get_reltime(&now) == 0 &&
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os_reltime_expired(&now, &target->last_update,
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age_secs)) {
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wpa_printf(MSG_DEBUG,
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"Candidate BSS is more than %ld seconds old",
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age_secs);
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continue;
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}
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}
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if (bss->ssid_len != target->ssid_len ||
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os_memcmp(bss->ssid, target->ssid, bss->ssid_len) != 0) {
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/*
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@ -832,6 +846,41 @@ static void wnm_send_bss_transition_mgmt_resp(
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}
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static void wnm_bss_tm_connect(struct wpa_supplicant *wpa_s,
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struct wpa_bss *bss, struct wpa_ssid *ssid,
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int after_new_scan)
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{
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wpa_dbg(wpa_s, MSG_DEBUG,
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"WNM: Transition to BSS " MACSTR
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" based on BSS Transition Management Request (old BSSID "
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MACSTR " after_new_scan=%d)",
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MAC2STR(bss->bssid), MAC2STR(wpa_s->bssid), after_new_scan);
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/* Send the BSS Management Response - Accept */
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if (wpa_s->wnm_reply) {
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wpa_s->wnm_reply = 0;
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wpa_printf(MSG_DEBUG,
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"WNM: Sending successful BSS Transition Management Response");
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wnm_send_bss_transition_mgmt_resp(wpa_s,
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wpa_s->wnm_dialog_token,
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WNM_BSS_TM_ACCEPT,
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0, bss->bssid);
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}
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if (bss == wpa_s->current_bss) {
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wpa_printf(MSG_DEBUG,
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"WNM: Already associated with the preferred candidate");
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wnm_deallocate_memory(wpa_s);
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return;
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}
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wpa_s->reassociate = 1;
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wpa_printf(MSG_DEBUG, "WNM: Issuing connect");
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wpa_supplicant_connect(wpa_s, bss, ssid);
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wnm_deallocate_memory(wpa_s);
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}
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int wnm_scan_process(struct wpa_supplicant *wpa_s, int reply_on_fail)
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{
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struct wpa_bss *bss;
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@ -841,6 +890,8 @@ int wnm_scan_process(struct wpa_supplicant *wpa_s, int reply_on_fail)
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if (!wpa_s->wnm_neighbor_report_elements)
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return 0;
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wpa_dbg(wpa_s, MSG_DEBUG,
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"WNM: Process scan results for BSS Transition Management");
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if (os_reltime_before(&wpa_s->wnm_cand_valid_until,
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&wpa_s->scan_trigger_time)) {
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wpa_printf(MSG_DEBUG, "WNM: Previously stored BSS transition candidate list is not valid anymore - drop it");
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@ -856,7 +907,7 @@ int wnm_scan_process(struct wpa_supplicant *wpa_s, int reply_on_fail)
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}
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/* Compare the Neighbor Report and scan results */
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bss = compare_scan_neighbor_results(wpa_s);
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bss = compare_scan_neighbor_results(wpa_s, 0);
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if (!bss) {
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wpa_printf(MSG_DEBUG, "WNM: No BSS transition candidate match found");
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status = WNM_BSS_TM_REJECT_NO_SUITABLE_CANDIDATES;
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@ -864,25 +915,7 @@ int wnm_scan_process(struct wpa_supplicant *wpa_s, int reply_on_fail)
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}
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/* Associate to the network */
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/* Send the BSS Management Response - Accept */
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if (wpa_s->wnm_reply) {
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wpa_s->wnm_reply = 0;
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wnm_send_bss_transition_mgmt_resp(wpa_s,
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wpa_s->wnm_dialog_token,
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WNM_BSS_TM_ACCEPT,
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0, bss->bssid);
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}
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if (bss == wpa_s->current_bss) {
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wpa_printf(MSG_DEBUG,
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"WNM: Already associated with the preferred candidate");
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wnm_deallocate_memory(wpa_s);
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return 1;
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}
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wpa_s->reassociate = 1;
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wpa_supplicant_connect(wpa_s, bss, ssid);
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wnm_deallocate_memory(wpa_s);
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wnm_bss_tm_connect(wpa_s, bss, ssid, 1);
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return 1;
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send_bss_resp_fail:
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@ -1023,6 +1056,79 @@ static void wnm_set_scan_freqs(struct wpa_supplicant *wpa_s)
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}
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static int wnm_fetch_scan_results(struct wpa_supplicant *wpa_s)
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{
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struct wpa_scan_results *scan_res;
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struct wpa_bss *bss;
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struct wpa_ssid *ssid = wpa_s->current_ssid;
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u8 i, found = 0;
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size_t j;
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wpa_dbg(wpa_s, MSG_DEBUG,
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"WNM: Fetch current scan results from the driver for checking transition candidates");
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scan_res = wpa_drv_get_scan_results2(wpa_s);
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if (!scan_res) {
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wpa_dbg(wpa_s, MSG_DEBUG, "WNM: Failed to get scan results");
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return 0;
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}
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if (scan_res->fetch_time.sec == 0)
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os_get_reltime(&scan_res->fetch_time);
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filter_scan_res(wpa_s, scan_res);
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for (i = 0; i < wpa_s->wnm_num_neighbor_report; i++) {
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struct neighbor_report *nei;
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nei = &wpa_s->wnm_neighbor_report_elements[i];
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if (nei->preference_present && nei->preference == 0)
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continue;
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for (j = 0; j < scan_res->num; j++) {
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struct wpa_scan_res *res;
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const u8 *ssid_ie;
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res = scan_res->res[j];
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if (os_memcmp(nei->bssid, res->bssid, ETH_ALEN) != 0 ||
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res->age > WNM_SCAN_RESULT_AGE * 1000)
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continue;
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bss = wpa_s->current_bss;
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ssid_ie = wpa_scan_get_ie(res, WLAN_EID_SSID);
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if (bss && ssid_ie &&
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(bss->ssid_len != ssid_ie[1] ||
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os_memcmp(bss->ssid, ssid_ie + 2,
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bss->ssid_len) != 0))
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continue;
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/* Potential candidate found */
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found = 1;
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scan_snr(res);
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scan_est_throughput(wpa_s, res);
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wpa_bss_update_scan_res(wpa_s, res,
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&scan_res->fetch_time);
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}
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}
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wpa_scan_results_free(scan_res);
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if (!found) {
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wpa_dbg(wpa_s, MSG_DEBUG,
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"WNM: No transition candidate matches existing scan results");
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return 0;
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}
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bss = compare_scan_neighbor_results(wpa_s, WNM_SCAN_RESULT_AGE);
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if (!bss) {
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wpa_dbg(wpa_s, MSG_DEBUG,
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"WNM: Comparison of scan results against transition candidates did not find matches");
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return 0;
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}
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/* Associate to the network */
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wnm_bss_tm_connect(wpa_s, bss, ssid, 0);
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return 1;
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}
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static void ieee802_11_rx_bss_trans_mgmt_req(struct wpa_supplicant *wpa_s,
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const u8 *pos, const u8 *end,
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int reply)
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@ -1155,6 +1261,20 @@ static void ieee802_11_rx_bss_trans_mgmt_req(struct wpa_supplicant *wpa_s,
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wpa_s->wnm_cand_valid_until.usec %= 1000000;
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os_memcpy(wpa_s->wnm_cand_from_bss, wpa_s->bssid, ETH_ALEN);
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/*
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* Fetch the latest scan results from the kernel and check for
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* candidates based on those results first. This can help in
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* finding more up-to-date information should the driver has
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* done some internal scanning operations after the last scan
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* result update in wpa_supplicant.
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*/
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if (wnm_fetch_scan_results(wpa_s) > 0)
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return;
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/*
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* Try to use previously received scan results, if they are
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* recent enough to use for a connection.
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*/
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if (wpa_s->last_scan_res_used > 0) {
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struct os_reltime now;
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