WNM: Move driver MBO transition rejection into wnm_is_bss_excluded()

Change the logic a bit to not directly use the result of the
wpa_drv_get_bss_trans_status() call and instead use the same selection
logic as usual but taking into account the driver rejections.

This changes the logic in minor ways. The main change is that this
aligns the ordering of BSSs to be identical in all cases. More
precisely, we'll select the best BSS as found by find_better_target().

Beyond that, it also means that in the case of an non-abridged BTM
request we'll also consider candidates that were found through the scan
and not in the neighbor report. In this case, the driver will not have a
chance to reject them.

Signed-off-by: Benjamin Berg <benjamin.berg@intel.com>

diff --git a/wpa_supplicant/wnm_sta.c b/wpa_supplicant/wnm_sta.c
index 662f6089e6f54548714ffbd9282d487cd89fb6b1..67e8df5f56a20e8877116d139f2a39b3bed40502 100644 (file)
--- a/wpa_supplicant/wnm_sta.c
+++ b/wpa_supplicant/wnm_sta.c
@@ -614,38 +614,37 @@ static void wnm_parse_neighbor_report(struct wpa_supplicant *wpa_s,
 }
 
 
-static void wnm_clear_acceptable(struct wpa_supplicant *wpa_s)
-{
-       unsigned int i;
-
-       for (i = 0; i < wpa_s->wnm_num_neighbor_report; i++)
-               wpa_s->wnm_neighbor_report_elements[i].acceptable = 0;
-}
-
-#ifdef CONFIG_MBO
-static struct wpa_bss *
-get_mbo_transition_candidate(struct wpa_supplicant *wpa_s,
+static void
+fetch_drv_mbo_candidate_info(struct wpa_supplicant *wpa_s,
                             enum mbo_transition_reject_reason *reason)
 {
-       struct wpa_bss *target = NULL;
+#ifdef CONFIG_MBO
        struct wpa_bss_trans_info params;
        struct wpa_bss_candidate_info *info = NULL;
-       struct neighbor_report *nei = wpa_s->wnm_neighbor_report_elements;
-       u8 *first_candidate_bssid = NULL, *pos;
+       struct neighbor_report *nei;
+       u8 *pos;
        unsigned int i;
 
+       if (!wpa_s->wnm_mbo_trans_reason_present)
+               return;
+
        params.mbo_transition_reason = wpa_s->wnm_mbo_transition_reason;
        params.n_candidates = 0;
        params.bssid = os_calloc(wpa_s->wnm_num_neighbor_report, ETH_ALEN);
        if (!params.bssid)
-               return NULL;
+               return;
 
        pos = params.bssid;
-       for (i = 0; i < wpa_s->wnm_num_neighbor_report; nei++, i++) {
-               if (nei->is_first)
-                       first_candidate_bssid = nei->bssid;
-               if (!nei->acceptable)
+       for (i = 0; i < wpa_s->wnm_num_neighbor_report; i++) {
+               nei = &wpa_s->wnm_neighbor_report_elements[i];
+
+               nei->drv_mbo_reject = 0;
+
+               if (nei->preference_present && nei->preference == 0)
                        continue;
+
+               /* Should we query BSSIDs that we reject for other reasons? */
+
                os_memcpy(pos, nei->bssid, ETH_ALEN);
                pos += ETH_ALEN;
                params.n_candidates++;
@@ -655,64 +654,37 @@ get_mbo_transition_candidate(struct wpa_supplicant *wpa_s,
                goto end;
 
        info = wpa_drv_get_bss_trans_status(wpa_s, &params);
-       if (!info) {
-               /* If failed to get candidate BSS transition status from driver,
-                * get the first acceptable candidate from wpa_supplicant.
-                */
-               target = wpa_bss_get_bssid(wpa_s, params.bssid);
+       if (!info)
                goto end;
-       }
 
-       /* Get the first acceptable candidate from driver */
        for (i = 0; i < info->num; i++) {
-               if (info->candidates[i].is_accept) {
-                       target = wpa_bss_get_bssid(wpa_s,
-                                                  info->candidates[i].bssid);
-                       goto end;
-               }
-       }
+               int j;
 
-       /* If Disassociation Imminent is set and driver rejects all the
-        * candidate select first acceptable candidate which has
-        * rssi > disassoc_imminent_rssi_threshold
-        */
-       if (wpa_s->wnm_mode & WNM_BSS_TM_REQ_DISASSOC_IMMINENT) {
-               for (i = 0; i < info->num; i++) {
-                       target = wpa_bss_get_bssid(wpa_s,
-                                                  info->candidates[i].bssid);
-                       if (target &&
-                           (target->level <
-                            wpa_s->conf->disassoc_imminent_rssi_threshold))
+               for (j = 0; j < wpa_s->wnm_num_neighbor_report; j++) {
+                       nei = &wpa_s->wnm_neighbor_report_elements[j];
+
+                       if (!ether_addr_equal(info->candidates[i].bssid,
+                                             nei->bssid))
                                continue;
-                       goto end;
-               }
-       }
 
-       /* While sending BTM reject use reason code of the first candidate
-        * received in BTM request frame
-        */
-       if (reason) {
-               for (i = 0; i < info->num; i++) {
-                       if (first_candidate_bssid &&
-                           ether_addr_equal(first_candidate_bssid,
-                                            info->candidates[i].bssid)) {
+                       nei->drv_mbo_reject = !info->candidates[i].is_accept;
+
+                       /* Use the reject reason from "first" candidate */
+                       if (nei->is_first && nei->drv_mbo_reject)
                                *reason = info->candidates[i].reject_reason;
-                               break;
-                       }
+
+                       break;
                }
        }
 
-       target = NULL;
-
 end:
        os_free(params.bssid);
        if (info) {
                os_free(info->candidates);
                os_free(info);
        }
-       return target;
-}
 #endif /* CONFIG_MBO */
+}
 
 
 static struct wpa_bss * find_better_target(struct wpa_bss *a,
@@ -754,8 +726,6 @@ compare_scan_neighbor_results(struct wpa_supplicant *wpa_s,
        wpa_printf(MSG_DEBUG, "WNM: Current BSS " MACSTR " RSSI %d",
                   MAC2STR(wpa_s->bssid), bss->level);
 
-       wnm_clear_acceptable(wpa_s);
-
        for (i = 0; i < wpa_s->wnm_num_neighbor_report; i++) {
                struct neighbor_report *nei;
 
@@ -795,21 +765,12 @@ compare_scan_neighbor_results(struct wpa_supplicant *wpa_s,
                        continue;
                }
 
-               nei->acceptable = 1;
-
                best_target = find_better_target(target, best_target);
                if (target == bss)
                        bss_in_list = bss;
        }
 
-#ifdef CONFIG_MBO
-       if (wpa_s->wnm_mbo_trans_reason_present)
-               target = get_mbo_transition_candidate(wpa_s, reason);
-       else
-               target = best_target;
-#else /* CONFIG_MBO */
        target = best_target;
-#endif /* CONFIG_MBO */
 
        if (!target)
                return NULL;
@@ -1178,8 +1139,37 @@ int wnm_scan_process(struct wpa_supplicant *wpa_s, bool pre_scan_check)
 
        wpa_s->wnm_transition_scan = false;
 
+       /* Fetch MBO transition candidate rejection information from driver */
+       fetch_drv_mbo_candidate_info(wpa_s, &reason);
+
        /* Compare the Neighbor Report and scan results */
        bss = compare_scan_neighbor_results(wpa_s, &reason);
+#ifdef CONFIG_MBO
+       if (!bss && wpa_s->wnm_mbo_trans_reason_present &&
+           (wpa_s->wnm_mode & WNM_BSS_TM_REQ_DISASSOC_IMMINENT)) {
+               int i;
+
+               /*
+                * We didn't find any candidate, the driver had a say about
+                * which targets to reject and disassociation is immiment.
+                *
+                * We should still try to roam, so retry after ignoring the
+                * driver reject for any BSS that has an RSSI better than
+                * disassoc_imminent_rssi_threshold.
+                */
+               for (i = 0; i < wpa_s->wnm_num_neighbor_report; i++) {
+                       struct neighbor_report *nei;
+
+                       nei = &wpa_s->wnm_neighbor_report_elements[i];
+                       bss = wpa_bss_get_bssid(wpa_s, nei->bssid);
+                       if (bss && bss->level >
+                           wpa_s->conf->disassoc_imminent_rssi_threshold)
+                               nei->drv_mbo_reject = 0;
+               }
+
+               bss = compare_scan_neighbor_results(wpa_s, &reason);
+       }
+#endif /* CONFIG_MBO */
 
        /*
         * If this is a pre-scan check, returning 0 will trigger a scan and
@@ -2118,6 +2108,11 @@ bool wnm_is_bss_excluded(struct wpa_supplicant *wpa_s, struct wpa_bss *bss)
                if (nei->preference_present && nei->preference == 0)
                        return true;
 
+#ifdef CONFIG_MBO
+               if (nei->drv_mbo_reject)
+                       return true;
+#endif /* CONFIG_MBO */
+
                break;
        }
 

diff --git a/wpa_supplicant/wnm_sta.h b/wpa_supplicant/wnm_sta.h
index 235a838fab7756a21c7f69621023b3ddb31c7134..5994027a448c5380fafa290d7f710450a7b16212 100644 (file)
--- a/wpa_supplicant/wnm_sta.h
+++ b/wpa_supplicant/wnm_sta.h
@@ -44,9 +44,9 @@ struct neighbor_report {
        unsigned int rm_capab_present:1;
        unsigned int bearing_present:1;
        unsigned int bss_term_present:1;
-       unsigned int acceptable:1;
 #ifdef CONFIG_MBO
        unsigned int is_first:1;
+       unsigned int drv_mbo_reject:1;
 #endif /* CONFIG_MBO */
        struct measurement_pilot *meas_pilot;
        struct multiple_bssid *mul_bssid;