qcacld-2.0: Use Reassociation during BSS Transition

The BSS transition request is handled by the supplicant.
The supplicant upon receiving the request will issue a
connect request to the driver with a hint of prev_bssid
telling the driver to perform a re-association.
Use this hint in the driver and initiate a re-association.
While doing the re-association, there is no need to do a
scan if the target AP is already present in the scan cache.
Optimize the re-association code to not do a scan if not
necessary in this particular case.

Change-Id: Idf1a7058009a8d2082bc1742dca1364cf59c405b
CRs-Fixed: 1010596

5 files changed, 94 insertions, 26 deletions

diff --git a/CORE/HDD/inc/wlan_hdd_main.h b/CORE/HDD/inc/wlan_hdd_main.h
index 0fd2ed9ed98e..1d63c2ea397e 100644
--- a/CORE/HDD/inc/wlan_hdd_main.h
+++ b/CORE/HDD/inc/wlan_hdd_main.h
@@ -2216,4 +2216,7 @@ static inline void wlan_hdd_restart_sap(hdd_adapter_t *ap_adapter)
 {
 }
 #endif
+
+int hdd_reassoc(hdd_adapter_t *pAdapter, const tANI_U8 *bssid,
+		const tANI_U8 channel, const handoff_src src);
 #endif    // end #if !defined( WLAN_HDD_MAIN_H )
diff --git a/CORE/HDD/src/wlan_hdd_cfg80211.c b/CORE/HDD/src/wlan_hdd_cfg80211.c
index c8427d1adae5..3967a606bc8b 100644
--- a/CORE/HDD/src/wlan_hdd_cfg80211.c
+++ b/CORE/HDD/src/wlan_hdd_cfg80211.c
@@ -18566,6 +18566,41 @@ disconnected:
     return result;
 }
 
+/**
+ * wlan_hdd_reassoc_bssid_hint() - Start reassociation if bssid is present
+ * @adapter: Pointer to the HDD adapter
+ * @req: Pointer to the structure cfg_connect_params receieved from user space
+ *
+ * This function will start reassociation if bssid hint, channel hint and
+ * previous bssid parameters are present in the connect request
+ *
+ * Return: success if reassociation is happening
+ *         Error code if reassociation is not permitted or not happening
+ */
+#ifdef CFG80211_CONNECT_PREV_BSSID
+static int wlan_hdd_reassoc_bssid_hint(hdd_adapter_t *adapter,
+				struct cfg80211_connect_params *req)
+{
+	int status = -EPERM;
+	if (req->bssid_hint && req->channel_hint && req->prev_bssid) {
+		hddLog(VOS_TRACE_LEVEL_INFO,
+			FL("REASSOC Attempt on channel %d to "MAC_ADDRESS_STR),
+			req->channel_hint->hw_value,
+			MAC_ADDR_ARRAY(req->bssid_hint));
+		status  = hdd_reassoc(adapter, req->bssid_hint,
+					req->channel_hint->hw_value,
+					CONNECT_CMD_USERSPACE);
+	}
+	return status;
+}
+#else
+static int wlan_hdd_reassoc_bssid_hint(hdd_adapter_t *adapter,
+				struct cfg80211_connect_params *req)
+{
+	return -EPERM;
+}
+#endif
+
 /*
  * FUNCTION: __wlan_hdd_cfg80211_connect
  * This function is used to start the association process
@@ -18614,6 +18649,10 @@ static int __wlan_hdd_cfg80211_connect( struct wiphy *wiphy,
     if (0 != status)
         return status;
 
+    status = wlan_hdd_reassoc_bssid_hint(pAdapter, req);
+    if (0 == status)
+        return status;
+
 #if defined(FEATURE_WLAN_LFR) && defined(WLAN_FEATURE_ROAM_SCAN_OFFLOAD)
     wlan_hdd_disable_roaming(pAdapter);
 #endif
diff --git a/CORE/HDD/src/wlan_hdd_main.c b/CORE/HDD/src/wlan_hdd_main.c
index 7b04621644db..0df86d6bd6ab 100644
--- a/CORE/HDD/src/wlan_hdd_main.c
+++ b/CORE/HDD/src/wlan_hdd_main.c
@@ -1850,18 +1850,17 @@ static int hdd_parse_reassoc_command_v1_data(const tANI_U8 *pValue,
     return VOS_STATUS_SUCCESS;
 }
 
-/*
-  \brief hdd_reassoc() - perform a user space-directed reassoc
-
-  \param - pAdapter - Adapter upon which the command was received
-  \param - bssid - BSSID with which to reassociate
-  \param - channel - channel upon which to reassociate
-
-  \return - 0 for success non-zero for failure
-
-  --------------------------------------------------------------------------*/
-static int
-hdd_reassoc(hdd_adapter_t *pAdapter, const tANI_U8 *bssid, const tANI_U8 channel)
+/**
+ * hdd_reassoc() - perform a user space directed reassoc
+ * @pAdapter: Adapter upon which the command was received
+ * @bssid:    BSSID with which to reassociate
+ * @channel:  channel upon which to reassociate
+ * @src:      The source for the trigger of this action
+ *
+ * Return:    0 for success non-zero for failure
+ */
+int hdd_reassoc(hdd_adapter_t *pAdapter, const tANI_U8 *bssid,
+                const tANI_U8 channel, const handoff_src src)
 {
    hdd_station_ctx_t *pHddStaCtx;
    int ret = 0;
@@ -1901,7 +1900,7 @@ hdd_reassoc(hdd_adapter_t *pAdapter, const tANI_U8 *bssid, const tANI_U8 channel
       hdd_context_t *pHddCtx = WLAN_HDD_GET_CTX(pAdapter);
 
       handoffInfo.channel = channel;
-      handoffInfo.src = REASSOC;
+      handoffInfo.src = src;
       memcpy(handoffInfo.bssid, bssid, sizeof(tSirMacAddr));
       sme_HandoffRequest(pHddCtx->hHal, pAdapter->sessionId, &handoffInfo);
    }
@@ -1942,7 +1941,7 @@ hdd_parse_reassoc_v1(hdd_adapter_t *pAdapter, const char *command)
       hddLog(VOS_TRACE_LEVEL_ERROR,
              "%s: Failed to parse reassoc command data", __func__);
    } else {
-      ret = hdd_reassoc(pAdapter, bssid, channel);
+      ret = hdd_reassoc(pAdapter, bssid, channel, REASSOC);
    }
    return ret;
 }
@@ -1976,7 +1975,7 @@ hdd_parse_reassoc_v2(hdd_adapter_t *pAdapter,
       hddLog(LOGE, "%s: MAC address parsing failed", __func__);
       ret = -EINVAL;
    } else {
-      ret = hdd_reassoc(pAdapter, bssid, params.channel);
+      ret = hdd_reassoc(pAdapter, bssid, params.channel, REASSOC);
    }
    return ret;
 }
diff --git a/CORE/SME/inc/csrApi.h b/CORE/SME/inc/csrApi.h
index 18e13f1a23bb..36d9e7dc0832 100644
--- a/CORE/SME/inc/csrApi.h
+++ b/CORE/SME/inc/csrApi.h
@@ -1672,12 +1672,6 @@ typedef void * tScanResultHandle;
 #define CSR_INVALID_SCANRESULT_HANDLE       (NULL)
 
 #ifdef WLAN_FEATURE_ROAM_SCAN_OFFLOAD
-typedef enum
-{
-    REASSOC     = 0,
-    FASTREASSOC = 1
-}handoff_src;
-
 typedef struct tagCsrHandoffRequest
 {
     tCsrBssid bssid;
@@ -1686,6 +1680,13 @@ typedef struct tagCsrHandoffRequest
 }tCsrHandoffRequest;
 #endif
 
+typedef enum
+{
+    REASSOC     = 0,
+    FASTREASSOC = 1,
+    CONNECT_CMD_USERSPACE = 2,
+}handoff_src;
+
 #if defined(FEATURE_WLAN_ESE) && defined(FEATURE_WLAN_ESE_UPLOAD)
 typedef struct tagCsrEseBeaconReqParams
 {
diff --git a/CORE/SME/src/csr/csrNeighborRoam.c b/CORE/SME/src/csr/csrNeighborRoam.c
index 5354b8c6c1a6..b48575d592a8 100644
--- a/CORE/SME/src/csr/csrNeighborRoam.c
+++ b/CORE/SME/src/csr/csrNeighborRoam.c
@@ -1818,6 +1818,9 @@ csrNeighborRoamPrepareScanProfileFilter(tpAniSirGlobal pMac,
 #ifdef WLAN_FEATURE_ROAM_SCAN_OFFLOAD
     if (pNeighborRoamInfo->uOsRequestedHandoff)
     {
+
+        VOS_TRACE (VOS_MODULE_ID_SME, VOS_TRACE_LEVEL_DEBUG,
+                   FL("OS Requested Handoff"));
         pScanFilter->BSSIDs.numOfBSSIDs = 1;
         pScanFilter->BSSIDs.bssid = vos_mem_malloc(sizeof(tSirMacAddr) * pScanFilter->BSSIDs.numOfBSSIDs);
         if (NULL == pScanFilter->BSSIDs.bssid)
@@ -6071,6 +6074,10 @@ eHalStatus csrNeighborRoamProcessHandoffReq(tpAniSirGlobal pMac,
     tCsrRoamProfile *pProfile = NULL;
     tCsrRoamSession *pSession = CSR_GET_SESSION(pMac, sessionId);
     tANI_U8 i = 0;
+    uint8_t roam_now = 0;
+    uint8_t roamable_ap_count = 0;
+    tCsrScanResultFilter    scan_filter;
+    tScanResultHandle       scan_result;
 
     if (NULL == pSession)
     {
@@ -6134,11 +6141,30 @@ eHalStatus csrNeighborRoamProcessHandoffReq(tpAniSirGlobal pMac,
         }
         pProfile->ChannelInfo.ChannelList[0] = pNeighborRoamInfo->handoffReqInfo.channel;
 
-        //do a SSID scan
-        status = csrScanForSSID(pMac, sessionId, pProfile, roamId, FALSE);
-        if(!HAL_STATUS_SUCCESS(status))
-        {
-            smsLog(pMac, LOGE, FL("SSID scan failed"));
+        /*
+         * For User space connect requests, the scan has already been done.
+         * So, check if the BSS descriptor exists in the scan cache and
+         * proceed with the handoff instead of a redundant scan again.
+         */
+        if (pNeighborRoamInfo->handoffReqInfo.src == CONNECT_CMD_USERSPACE) {
+            smsLog(pMac, LOG1, FL("Connect cmd with bssid within same ESS"));
+            status = csrNeighborRoamPrepareScanProfileFilter(
+                                               pMac, &scan_filter, sessionId);
+            smsLog(pMac, LOG1, FL("Filter creation status = %d"), status);
+            status = csrScanGetResult(pMac, &scan_filter, &scan_result);
+            roam_now = csrNeighborRoamProcessScanResults(pMac, sessionId,
+                                                          &scan_result);
+            roamable_ap_count = csrLLCount(&pNeighborRoamInfo->roamableAPList);
+            csrFreeScanFilter(pMac, &scan_filter);
+            smsLog(pMac, LOG1, FL("roam_now=%d, roamable_ap_count=%d"),
+                   roam_now, roamable_ap_count);
+        }
+        if (roam_now && roamable_ap_count) {
+            csrNeighborRoamTriggerHandoff(pMac, sessionId);
+        } else {
+            status = csrScanForSSID(pMac, sessionId, pProfile, roamId, FALSE);
+            if(!HAL_STATUS_SUCCESS(status))
+               smsLog(pMac, LOGE, FL("SSID scan failed"));
         }
     }while(0);