wifi: MBO-OCE feature support (phase 2)

1. MBO-OCE IE parsing
2. Skip MBO APs which are not accepting new connections from
network selection.

Bug: 139474288
Test: atest com.android.server.wifi
Test: Manual
Change-Id: I7b8dd7540465adac07c1e55e43f0848c1b1af02b

4 files changed, 192 insertions, 5 deletions

diff --git a/service/java/com/android/server/wifi/MboOceConstants.java b/service/java/com/android/server/wifi/MboOceConstants.java
new file mode 100644
index 000000000..a7f5fefab
--- /dev/null
+++ b/service/java/com/android/server/wifi/MboOceConstants.java
@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.wifi;
+
+import android.annotation.IntDef;
+
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+
+/**
+ * MBO-OCE related constants
+ */
+public class MboOceConstants {
+
+    public static final int MBO_OCE_ATTRIBUTE_NOT_PRESENT = -1;
+
+    /** MBO-OCE attribute Ids */
+    public static final int MBO_OCE_AID_MBO_AP_CAPABILITY_INDICATION = 0x01;
+    public static final int MBO_OCE_AID_NON_PREFERRED_CHANNEL_REPORT = 0x02;
+    public static final int MBO_OCE_AID_CELLULAR_DATA_CAPABILITIES = 0x03;
+    public static final int MBO_OCE_AID_ASSOCIATION_DISALLOWED = 0x04;
+    public static final int MBO_OCE_AID_CELLULAR_DATA_CONNECTION_PREFERENCE = 0x05;
+    public static final int MBO_OCE_AID_TRANSITION_REASON_CODE = 0x06;
+    public static final int MBO_OCE_AID_TRANSITION_REJECTION_REASON_CODE = 0x07;
+    public static final int MBO_OCE_AID_ASSOCIATION_RETRY_DELAY = 0x08;
+    public static final int MBO_OCE_AID_OCE_AP_CAPABILITY_INDICATION = 0x65;
+    public static final int MBO_OCE_AID_RSSI_BASED_ASSOCIATION_REJECTION = 0x66;
+    public static final int MBO_OCE_AID_REDUCED_WAN_METRICS = 0x67;
+    public static final int MBO_OCE_AID_RNR_COMPLETENESS = 0x68;
+    public static final int MBO_OCE_AID_PROBE_SUPPRESSION_BSSIDS = 0x69;
+    public static final int MBO_OCE_AID_PROBE_SUPPRESSION_SSIDS = 0x6A;
+
+    @IntDef(prefix = { "MBO_OCE_AID_" }, value = {
+            MBO_OCE_AID_MBO_AP_CAPABILITY_INDICATION,
+            MBO_OCE_AID_NON_PREFERRED_CHANNEL_REPORT,
+            MBO_OCE_AID_CELLULAR_DATA_CAPABILITIES,
+            MBO_OCE_AID_ASSOCIATION_DISALLOWED,
+            MBO_OCE_AID_CELLULAR_DATA_CONNECTION_PREFERENCE,
+            MBO_OCE_AID_TRANSITION_REASON_CODE,
+            MBO_OCE_AID_TRANSITION_REJECTION_REASON_CODE,
+            MBO_OCE_AID_ASSOCIATION_RETRY_DELAY,
+            MBO_OCE_AID_OCE_AP_CAPABILITY_INDICATION,
+            MBO_OCE_AID_RSSI_BASED_ASSOCIATION_REJECTION,
+            MBO_OCE_AID_REDUCED_WAN_METRICS,
+            MBO_OCE_AID_RNR_COMPLETENESS,
+            MBO_OCE_AID_PROBE_SUPPRESSION_BSSIDS,
+            MBO_OCE_AID_PROBE_SUPPRESSION_SSIDS
+    })
+    @Retention(RetentionPolicy.SOURCE)
+    @interface MboOceAid{}
+
+    public static final int MBO_AP_CAP_IND_ATTR_CELL_DATA_AWARE = 0x40;
+}
diff --git a/service/java/com/android/server/wifi/WifiNetworkSelector.java b/service/java/com/android/server/wifi/WifiNetworkSelector.java
index c8384614a..433fd0b01 100644
--- a/service/java/com/android/server/wifi/WifiNetworkSelector.java
+++ b/service/java/com/android/server/wifi/WifiNetworkSelector.java
@@ -36,6 +36,7 @@ import android.util.Pair;
 
 import com.android.internal.annotations.VisibleForTesting;
 import com.android.internal.util.Preconditions;
+import com.android.server.wifi.hotspot2.NetworkDetail;
 import com.android.server.wifi.proto.nano.WifiMetricsProto;
 import com.android.server.wifi.util.InformationElementUtil.BssLoad;
 import com.android.server.wifi.util.ScanResultUtil;
@@ -384,6 +385,7 @@ public class WifiNetworkSelector {
         StringBuffer noValidSsid = new StringBuffer();
         StringBuffer blacklistedBssid = new StringBuffer();
         StringBuffer lowRssi = new StringBuffer();
+        StringBuffer mboAssociationDisallowedBssid = new StringBuffer();
         boolean scanResultsHaveCurrentBssid = false;
 
         for (ScanDetail scanDetail : scanDetails) {
@@ -414,6 +416,18 @@ public class WifiNetworkSelector {
                 continue;
             }
 
+            // Skip BSS which is not accepting new connections.
+            NetworkDetail networkDetail = scanDetail.getNetworkDetail();
+            if (networkDetail != null) {
+                if (networkDetail.getMboAssociationDisallowedReasonCode()
+                        != MboOceConstants.MBO_OCE_ATTRIBUTE_NOT_PRESENT) {
+                    mboAssociationDisallowedBssid.append(scanId).append("(")
+                        .append(networkDetail.getMboAssociationDisallowedReasonCode())
+                        .append(")").append(" / ");
+                    continue;
+                }
+            }
+
             validScanDetails.add(scanDetail);
         }
 
@@ -440,6 +454,11 @@ public class WifiNetworkSelector {
             localLog("Networks filtered out due to low signal strength: " + lowRssi);
         }
 
+        if (mboAssociationDisallowedBssid.length() != 0) {
+            localLog("Networks filtered out due to mbo association disallowed indication: "
+                    + mboAssociationDisallowedBssid);
+        }
+
         return validScanDetails;
     }
 
diff --git a/service/java/com/android/server/wifi/hotspot2/NetworkDetail.java b/service/java/com/android/server/wifi/hotspot2/NetworkDetail.java
index b456ef486..743bc76ac 100644
--- a/service/java/com/android/server/wifi/hotspot2/NetworkDetail.java
+++ b/service/java/com/android/server/wifi/hotspot2/NetworkDetail.java
@@ -119,6 +119,13 @@ public class NetworkDetail {
 
     private final Map<Constants.ANQPElementType, ANQPElement> mANQPElements;
 
+    /*
+     * From Wi-Fi Alliance MBO-OCE Information element.
+     * mMboAssociationDisallowedReasonCode is the reason code for AP not accepting new connections
+     * and is set to -1 if association disallowed attribute is not present in the element.
+     */
+    private final int mMboAssociationDisallowedReasonCode;
+
     public NetworkDetail(String bssid, ScanResult.InformationElement[] infoElements,
             List<String> anqpLines, int freq) {
         if (infoElements == null) {
@@ -279,6 +286,7 @@ public class NetworkDetail {
         mInternet = interworking.internet;
         mHSRelease = vsa.hsRelease;
         mAnqpDomainID = vsa.anqpDomainID;
+        mMboAssociationDisallowedReasonCode = vsa.mboAssociationDisallowedReasonCode;
         mAnqpOICount = roamingConsortium.anqpOICount;
         mRoamingConsortiums = roamingConsortium.getRoamingConsortiums();
         mExtendedCapabilities = extendedCapabilities;
@@ -356,14 +364,16 @@ public class NetworkDetail {
         }
         if (DBG) {
             Log.d(TAG, mSSID + "ChannelWidth is: " + mChannelWidth + " PrimaryFreq: "
-                    + mPrimaryFreq + " mCenterfreq0: " + mCenterfreq0 + " mCenterfreq1: "
+                    + mPrimaryFreq + " Centerfreq0: " + mCenterfreq0 + " Centerfreq1: "
                     + mCenterfreq1 + (extendedCapabilities.is80211McRTTResponder()
                     ? " Support RTT responder" : " Do not support RTT responder")
-                    + " mMaxNumberSpatialStreams: " + mMaxNumberSpatialStreams);
+                    + " MaxNumberSpatialStreams: " + mMaxNumberSpatialStreams
+                    + " MboAssociationDisallowedReasonCode: "
+                    + mMboAssociationDisallowedReasonCode);
             Log.v("WifiMode", mSSID
                     + ", WifiMode: " + InformationElementUtil.WifiMode.toString(mWifiMode)
                     + ", Freq: " + mPrimaryFreq
-                    + ", mMaxRate: " + mMaxRate
+                    + ", MaxRate: " + mMaxRate
                     + ", HE: " + String.valueOf(heOperation.isPresent())
                     + ", VHT: " + String.valueOf(vhtOperation.isPresent())
                     + ", HT: " + String.valueOf(htOperation.isPresent())
@@ -406,6 +416,7 @@ public class NetworkDetail {
         mWifiMode = base.mWifiMode;
         mMaxRate = base.mMaxRate;
         mMaxNumberSpatialStreams = base.mMaxNumberSpatialStreams;
+        mMboAssociationDisallowedReasonCode = base.mMboAssociationDisallowedReasonCode;
     }
 
     public NetworkDetail complete(Map<Constants.ANQPElementType, ANQPElement> anqpElements) {
@@ -609,4 +620,8 @@ public class NetworkDetail {
         }
         return sb.toString();
     }
+
+    public int getMboAssociationDisallowedReasonCode() {
+        return mMboAssociationDisallowedReasonCode;
+    }
 }
diff --git a/service/java/com/android/server/wifi/util/InformationElementUtil.java b/service/java/com/android/server/wifi/util/InformationElementUtil.java
index 14f6a9f3e..0aff20432 100644
--- a/service/java/com/android/server/wifi/util/InformationElementUtil.java
+++ b/service/java/com/android/server/wifi/util/InformationElementUtil.java
@@ -20,6 +20,7 @@ import android.net.wifi.ScanResult.InformationElement;
 import android.util.Log;
 
 import com.android.server.wifi.ByteBufferReader;
+import com.android.server.wifi.MboOceConstants;
 import com.android.server.wifi.hotspot2.NetworkDetail;
 import com.android.server.wifi.hotspot2.anqp.Constants;
 
@@ -693,13 +694,65 @@ public class InformationElementUtil {
 
     public static class Vsa {
         private static final int ANQP_DOMID_BIT = 0x04;
+        private static final int OUI_WFA_ALLIANCE = 0x506F9a;
+        private static final int OUI_TYPE_HS20 = 0x10;
+        private static final int OUI_TYPE_MBO_OCE = 0x16;
 
         public NetworkDetail.HSRelease hsRelease = null;
         public int anqpDomainID = 0;    // No domain ID treated the same as a 0; unique info per AP.
 
-        public void from(InformationElement ie) {
+        public boolean IsMboCapable = false;
+        public boolean IsMboApCellularDataAware = false;
+        public boolean IsOceCapable = false;
+        public int mboAssociationDisallowedReasonCode =
+                MboOceConstants.MBO_OCE_ATTRIBUTE_NOT_PRESENT;
+
+        private void parseVsaMboOce(InformationElement ie) {
+            ByteBuffer data = ByteBuffer.wrap(ie.bytes).order(ByteOrder.LITTLE_ENDIAN);
+
+            // skip WFA OUI and type parsing as parseVsaMboOce() is called after identifying
+            // MBO-OCE OUI type.
+            data.getInt();
+
+            while (data.remaining() > 1) {
+                int attrId = data.get() & Constants.BYTE_MASK;
+                int attrLen = data.get() & Constants.BYTE_MASK;
+
+                if ((attrLen == 0) || (attrLen > data.remaining())) {
+                    return;
+                }
+                byte[] attrBytes = new byte[attrLen];
+                data.get(attrBytes);
+                switch (attrId) {
+                    case MboOceConstants.MBO_OCE_AID_MBO_AP_CAPABILITY_INDICATION:
+                        IsMboCapable = true;
+                        IsMboApCellularDataAware = (attrBytes[0]
+                                & MboOceConstants.MBO_AP_CAP_IND_ATTR_CELL_DATA_AWARE) != 0;
+                        break;
+                    case MboOceConstants.MBO_OCE_AID_ASSOCIATION_DISALLOWED:
+                        mboAssociationDisallowedReasonCode = attrBytes[0] & Constants.BYTE_MASK;
+                        break;
+                    case MboOceConstants.MBO_OCE_AID_OCE_AP_CAPABILITY_INDICATION:
+                        IsOceCapable = true;
+                        break;
+                    default:
+                        break;
+                }
+            }
+            if (DBG) {
+                Log.e(TAG, ":parseMboOce MBO: " + IsMboCapable + " cellDataAware: "
+                        + IsMboApCellularDataAware + " AssocDisAllowRC: "
+                        + mboAssociationDisallowedReasonCode + " :OCE: " + IsOceCapable);
+            }
+        }
+
+        private void parseVsaHs20(InformationElement ie) {
             ByteBuffer data = ByteBuffer.wrap(ie.bytes).order(ByteOrder.LITTLE_ENDIAN);
-            if (ie.bytes.length >= 5 && data.getInt() == Constants.HS20_FRAME_PREFIX) {
+            if (ie.bytes.length >= 5) {
+                // skip WFA OUI and type parsing as parseVsaHs20() is called after identifying
+                // HS20 OUI type.
+                data.getInt();
+
                 int hsConf = data.get() & Constants.BYTE_MASK;
                 switch ((hsConf >> 4) & Constants.NIBBLE_MASK) {
                     case 0:
@@ -721,6 +774,39 @@ public class InformationElementUtil {
                 }
             }
         }
+
+        /**
+         * Parse the vendor specific information element to build
+         * InformationElemmentUtil.vsa object.
+         *
+         * @param ie -- Information Element
+         */
+        public void from(InformationElement ie) {
+            if (ie.bytes.length < 3) {
+                if (DBG) {
+                    Log.w(TAG, "Invalid vendor specific element len: " + ie.bytes.length);
+                }
+                return;
+            }
+
+            int oui = (((ie.bytes[0] & Constants.BYTE_MASK) << 16)
+                       | ((ie.bytes[1] & Constants.BYTE_MASK) << 8)
+                       |  ((ie.bytes[2] & Constants.BYTE_MASK)));
+
+            if (oui == OUI_WFA_ALLIANCE && ie.bytes.length >= 4) {
+                int ouiType = ie.bytes[3];
+                switch (ouiType) {
+                    case OUI_TYPE_HS20:
+                        parseVsaHs20(ie);
+                        break;
+                    case OUI_TYPE_MBO_OCE:
+                        parseVsaMboOce(ie);
+                        break;
+                    default:
+                        break;
+                }
+            }
+        }
     }
 
     /**