WNM: Consolidate the scanning paths for BTM requests

There was an ancient code path to trigger a scan that was apparently
forgotten when the code was extended over time. It does not make any
sense to trigger a scan twice, so remove the earlier scan.

The earlier scan call was avoiding to trigger a new scan if a fixed
BSSID is configured. This seems like a reasonable restriction to do, so
add this check before starting a scan.

Consolidate everything so that scanning happens at the end of the
functions unless we bail out before. Add a "reset" label for all other
cases to ensure that we don't leave things in the a bad state.

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

diff --git a/wpa_supplicant/wnm_sta.c b/wpa_supplicant/wnm_sta.c
index b6c5455d60bf1cd7180be4f52ec2b96c587bc258..b355f6a685155f4ce8b5fbf7b08a3d0f5cbecd6d 100644 (file)
--- a/wpa_supplicant/wnm_sta.c
+++ b/wpa_supplicant/wnm_sta.c
@@ -1458,8 +1458,7 @@ static void ieee802_11_rx_bss_trans_mgmt_req(struct wpa_supplicant *wpa_s,
 
        if (!wpa_s->wnm_dialog_token) {
                wpa_printf(MSG_DEBUG, "WNM: Invalid dialog token");
-               wnm_btm_reset(wpa_s);
-               return;
+               goto reset;
        }
 
 #if defined(CONFIG_MBO) && defined(CONFIG_TESTING_OPTIONS)
@@ -1470,7 +1469,7 @@ static void ieee802_11_rx_bss_trans_mgmt_req(struct wpa_supplicant *wpa_s,
                wnm_send_bss_transition_mgmt_resp(
                        wpa_s, wpa_s->reject_btm_req_reason,
                        MBO_TRANSITION_REJECT_REASON_UNSPECIFIED, 0, NULL);
-               return;
+               goto reset;
        }
 #endif /* CONFIG_MBO && CONFIG_TESTING_OPTIONS */
 
@@ -1479,7 +1478,7 @@ static void ieee802_11_rx_bss_trans_mgmt_req(struct wpa_supplicant *wpa_s,
        if (wpa_s->wnm_mode & WNM_BSS_TM_REQ_BSS_TERMINATION_INCLUDED) {
                if (end - pos < 12) {
                        wpa_printf(MSG_DEBUG, "WNM: Too short BSS TM Request");
-                       return;
+                       goto reset;
                }
                os_memcpy(wpa_s->wnm_bss_termination_duration, pos, 12);
                pos += 12; /* BSS Termination Duration */
@@ -1492,13 +1491,13 @@ static void ieee802_11_rx_bss_trans_mgmt_req(struct wpa_supplicant *wpa_s,
                if (end - pos < 1) {
                        wpa_printf(MSG_DEBUG, "WNM: Invalid BSS Transition "
                                   "Management Request (URL)");
-                       return;
+                       goto reset;
                }
                url_len = *pos++;
                if (url_len > end - pos) {
                        wpa_printf(MSG_DEBUG,
                                   "WNM: Invalid BSS Transition Management Request (URL truncated)");
-                       return;
+                       goto reset;
                }
                os_memcpy(url, pos, url_len);
                url[url_len] = '\0';
@@ -1534,7 +1533,7 @@ static void ieee802_11_rx_bss_trans_mgmt_req(struct wpa_supplicant *wpa_s,
                        wnm_send_bss_transition_mgmt_resp(
                                wpa_s, WNM_BSS_TM_ACCEPT, 0, 0, NULL);
 
-                       return;
+                       goto reset;
                }
 
                /* The last link is being removed (which must be the assoc link)
@@ -1553,16 +1552,9 @@ static void ieee802_11_rx_bss_trans_mgmt_req(struct wpa_supplicant *wpa_s,
                os_memcpy(wpa_s->wnm_disassoc_addr, wpa_s->bssid, ETH_ALEN);
        }
 
-       if (disassoc_imminent) {
+       if (disassoc_imminent)
                wpa_msg(wpa_s, MSG_INFO, "WNM: Disassociation Imminent - "
                        "Disassociation Timer %u", wpa_s->wnm_disassoc_timer);
-               if (wpa_s->wnm_disassoc_timer && !wpa_s->scanning &&
-                   (!wpa_s->current_ssid || !wpa_s->current_ssid->bssid_set)) {
-                       wpa_printf(MSG_DEBUG, "Trying to find another BSS");
-                       wpa_s->wnm_transition_scan = true;
-                       wpa_supplicant_req_scan(wpa_s, 0, 0);
-               }
-       }
 
 #ifdef CONFIG_MBO
        vendor = get_ie(pos, end - pos, WLAN_EID_VENDOR_SPECIFIC);
@@ -1576,7 +1568,7 @@ static void ieee802_11_rx_bss_trans_mgmt_req(struct wpa_supplicant *wpa_s,
                wpa_msg(wpa_s, MSG_INFO, "WNM: Preferred List Available");
 
                if (wnm_parse_candidate_list(wpa_s, pos, end) < 0)
-                       return;
+                       goto reset;
 
                if (!wpa_s->wnm_num_neighbor_report) {
                        wpa_printf(MSG_DEBUG,
@@ -1585,17 +1577,7 @@ static void ieee802_11_rx_bss_trans_mgmt_req(struct wpa_supplicant *wpa_s,
                                wpa_s, WNM_BSS_TM_REJECT_NO_SUITABLE_CANDIDATES,
                                MBO_TRANSITION_REJECT_REASON_UNSPECIFIED, 0,
                                NULL);
-                       return;
-               }
-
-               if (wpa_s->current_ssid && wpa_s->current_ssid->bssid_set) {
-                       wpa_printf(MSG_DEBUG,
-                                  "WNM: Configuration prevents roaming (BSSID set)");
-                       wnm_send_bss_transition_mgmt_resp(
-                               wpa_s, WNM_BSS_TM_REJECT_NO_SUITABLE_CANDIDATES,
-                               MBO_TRANSITION_REJECT_REASON_UNSPECIFIED, 0,
-                               NULL);
-                       return;
+                       goto reset;
                }
 
                wnm_sort_cand_list(wpa_s);
@@ -1605,36 +1587,11 @@ static void ieee802_11_rx_bss_trans_mgmt_req(struct wpa_supplicant *wpa_s,
                           valid_ms);
                os_get_reltime(&wpa_s->wnm_cand_valid_until);
                os_reltime_add_ms(&wpa_s->wnm_cand_valid_until, valid_ms);
-
-               /*
-               * Try fetching the latest scan results from the kernel.
-               * This can help in finding more up-to-date information should
-               * the driver have done some internal scanning operations after
-               * the last scan result update in wpa_supplicant.
-               *
-               * It is not a new scan, this does not update the last_scan
-               * timestamp nor will it expire old BSSs.
-               */
-               wpa_supplicant_update_scan_results(wpa_s, NULL);
-               if (wnm_scan_process(wpa_s, true) > 0)
-                       return;
-               wpa_printf(MSG_DEBUG,
-                          "WNM: No valid match in previous scan results - try a new scan");
-
-               wnm_set_scan_freqs(wpa_s);
-               if (wpa_s->wnm_num_neighbor_report == 1) {
-                       os_memcpy(wpa_s->next_scan_bssid,
-                                 wpa_s->wnm_neighbor_report_elements[0].bssid,
-                                 ETH_ALEN);
-                       wpa_printf(MSG_DEBUG,
-                                  "WNM: Scan only for a specific BSSID since there is only a single candidate "
-                                  MACSTR, MAC2STR(wpa_s->next_scan_bssid));
-               }
-               wpa_s->wnm_transition_scan = true;
-               wpa_supplicant_req_scan(wpa_s, 0, 0);
-       } else if (reply) {
+       } else if (!disassoc_imminent) {
                enum bss_trans_mgmt_status_code status;
 
+               /* No candidate list and disassociation is not imminent */
+
                if ((wpa_s->wnm_mode & WNM_BSS_TM_REQ_ESS_DISASSOC_IMMINENT) ||
                    wpa_s->wnm_link_removal)
                        status = WNM_BSS_TM_ACCEPT;
@@ -1642,10 +1599,65 @@ static void ieee802_11_rx_bss_trans_mgmt_req(struct wpa_supplicant *wpa_s,
                        wpa_msg(wpa_s, MSG_INFO, "WNM: BSS Transition Management Request did not include candidates");
                        status = WNM_BSS_TM_REJECT_UNSPECIFIED;
                }
-               wnm_send_bss_transition_mgmt_resp(
-                       wpa_s, status,
-                       MBO_TRANSITION_REJECT_REASON_UNSPECIFIED, 0, NULL);
+
+               if (reply)
+                       wnm_send_bss_transition_mgmt_resp(
+                               wpa_s, status,
+                               MBO_TRANSITION_REJECT_REASON_UNSPECIFIED, 0,
+                               NULL);
+
+               goto reset;
+       }
+
+       /*
+        * Try fetching the latest scan results from the kernel.
+        * This can help in finding more up-to-date information should
+        * the driver have done some internal scanning operations after
+        * the last scan result update in wpa_supplicant.
+        *
+        * It is not a new scan, this does not update the last_scan
+        * timestamp nor will it expire old BSSs.
+        */
+       wpa_supplicant_update_scan_results(wpa_s, NULL);
+       if (wnm_scan_process(wpa_s, true) > 0)
+               return;
+       wpa_printf(MSG_DEBUG,
+                  "WNM: No valid match in previous scan results - try a new scan");
+
+       /*
+        * If we have a fixed BSSID configured, just reject at this point.
+        * NOTE: We could actually check if we are allowed to stay (and we do
+        * above if we have scan results available).
+        */
+       if (wpa_s->current_ssid && wpa_s->current_ssid->bssid_set) {
+               wpa_printf(MSG_DEBUG, "WNM: Fixed BSSID, rejecting request");
+
+               if (reply)
+                       wnm_send_bss_transition_mgmt_resp(
+                               wpa_s, WNM_BSS_TM_REJECT_NO_SUITABLE_CANDIDATES,
+                               MBO_TRANSITION_REJECT_REASON_UNSPECIFIED, 0,
+                               NULL);
+
+               goto reset;
        }
+
+       wnm_set_scan_freqs(wpa_s);
+       if (wpa_s->wnm_num_neighbor_report == 1) {
+               os_memcpy(wpa_s->next_scan_bssid,
+                         wpa_s->wnm_neighbor_report_elements[0].bssid,
+                         ETH_ALEN);
+               wpa_printf(MSG_DEBUG,
+                         "WNM: Scan only for a specific BSSID since there is only a single candidate "
+                         MACSTR, MAC2STR(wpa_s->next_scan_bssid));
+       }
+       wpa_s->wnm_transition_scan = true;
+       wpa_supplicant_req_scan(wpa_s, 0, 0);
+
+       /* Continue from scan handler */
+       return;
+
+reset:
+       wnm_btm_reset(wpa_s);
 }