MSCS: Extend MSCS response handling

Align MSCS response handling as described in IEEE P802.11-REVme/D4.0,
11.25.3 (MSCS procedures):

If an MSCS Descriptor element is present in a MSCS Response
frame that does not indicate a status of "SUCCESS", the request
type field is set to "change" - the element indicates a suggested
set of parameters that could be accepted by the AP in response to a
subsequent request by the non-AP STA.

Handle both MSCS Response frame and (Re)Association Response frame with
change request by extending WPA_EVENT_MSCS_RESULT with the change
values.

Note: since we extend MSCS_RESULT event, move the original event from
both MSCS Response frame and (Re)Association Response frame handlers to
a common function that handles now both 'change' and other response.

Signed-off-by: Daniel Gabay <daniel.gabay@intel.com>

diff --git a/wpa_supplicant/robust_av.c b/wpa_supplicant/robust_av.c
index dc4e9accec8b2985d533180f05dc7ba54e61cc60..993c2a47576eff076a57194322038fadcf97fd00 100644 (file)
--- a/wpa_supplicant/robust_av.c
+++ b/wpa_supplicant/robust_av.c
@@ -668,16 +668,78 @@ void free_up_scs_desc(struct scs_robust_av_data *data)
  * Stream Timeout(4) */
 #define MSCS_DESCRIPTOR_FIXED_LEN 8
 
+static void wpas_parse_mscs_resp(struct wpa_supplicant *wpa_s,
+                                u16 status, const u8 *bssid,
+                                const u8 *mscs_desc_ie)
+{
+       struct robust_av_data robust_av;
+       const u8 *pos;
+
+       /* The MSCS Descriptor element is optional in the MSCS Response frame */
+       if (!mscs_desc_ie)
+               goto event_mscs_result;
+
+       if (mscs_desc_ie[1] < MSCS_DESCRIPTOR_FIXED_LEN) {
+               wpa_printf(MSG_INFO,
+                          "MSCS: Drop received frame: invalid MSCS Descriptor element length: %d",
+                          mscs_desc_ie[1]);
+               return;
+       }
+
+       os_memset(&robust_av, 0, sizeof(struct robust_av_data));
+
+       /* Skip Element ID, Length, and Element ID Extension */
+       pos = &mscs_desc_ie[3];
+
+       robust_av.request_type = *pos++;
+
+       switch (robust_av.request_type) {
+       case SCS_REQ_CHANGE:
+               /*
+                * Inform the suggested set of parameters that could be accepted
+                * by the AP in response to a subsequent request by the station.
+                */
+               robust_av.up_bitmap = *pos++;
+               robust_av.up_limit = *pos++ & 0x07;
+               robust_av.stream_timeout = WPA_GET_LE32(pos);
+               wpa_msg(wpa_s, MSG_INFO, WPA_EVENT_MSCS_RESULT "bssid=" MACSTR
+                       " status_code=%u change up_bitmap=%u up_limit=%u stream_timeout=%u",
+                       MAC2STR(bssid), status, robust_av.up_bitmap,
+                       robust_av.up_limit, robust_av.stream_timeout);
+               wpa_s->mscs_setup_done = false;
+               return;
+       case SCS_REQ_ADD:
+               /*
+                * This type is used in (Re)Association Response frame MSCS
+                * Descriptor element if no change is required.
+                */
+               break;
+       default:
+               wpa_printf(MSG_INFO,
+                          "MSCS: Drop received frame with unknown Request Type: %u",
+                          robust_av.request_type);
+               return;
+       }
+
+event_mscs_result:
+       wpa_msg(wpa_s, MSG_INFO, WPA_EVENT_MSCS_RESULT "bssid=" MACSTR
+               " status_code=%u", MAC2STR(bssid), status);
+       wpa_s->mscs_setup_done = status == WLAN_STATUS_SUCCESS;
+}
+
+
 void wpas_handle_robust_av_recv_action(struct wpa_supplicant *wpa_s,
                                       const u8 *src, const u8 *buf, size_t len)
 {
        u8 dialog_token;
        u16 status_code;
+       const u8 *mscs_desc_ie;
 
        if (len < 3)
                return;
 
        dialog_token = *buf++;
+       len--;
        if (dialog_token != wpa_s->robust_av.dialog_token) {
                wpa_printf(MSG_INFO,
                           "MSCS: Drop received frame due to dialog token mismatch: received:%u expected:%u",
@@ -686,9 +748,11 @@ void wpas_handle_robust_av_recv_action(struct wpa_supplicant *wpa_s,
        }
 
        status_code = WPA_GET_LE16(buf);
-       wpa_msg(wpa_s, MSG_INFO, WPA_EVENT_MSCS_RESULT "bssid=" MACSTR
-               " status_code=%u", MAC2STR(src), status_code);
-       wpa_s->mscs_setup_done = status_code == WLAN_STATUS_SUCCESS;
+       buf += 2;
+       len -= 2;
+
+       mscs_desc_ie = get_ie_ext(buf, len, WLAN_EID_EXT_MSCS_DESCRIPTOR);
+       wpas_parse_mscs_resp(wpa_s, status_code, src, mscs_desc_ie);
 }
 
 
@@ -715,9 +779,8 @@ void wpas_handle_assoc_resp_mscs(struct wpa_supplicant *wpa_s, const u8 *bssid,
                return;
 
        status = WPA_GET_LE16(mscs_status + 2);
-       wpa_msg(wpa_s, MSG_INFO, WPA_EVENT_MSCS_RESULT "bssid=" MACSTR
-               " status_code=%u", MAC2STR(bssid), status);
-       wpa_s->mscs_setup_done = status == WLAN_STATUS_SUCCESS;
+
+       wpas_parse_mscs_resp(wpa_s, status, bssid, mscs_desc_ie);
 }