Keep debug information in NetworkStats files

Create two special SETs.

SET_DBG_VPN_IN is used by individual applications to know
how much traffic of the NetworkIdentity was actually moved
from a VPN app.
SET_DBG_VPN_OUT is used by the VPN app to know how much
traffic of the NetworkIdentity was deducted.

A debug application can restore the raw stats by these
entries.
  raw_traffic = recorded_entry (TAG_NONE, SET_ALL)
              + recorded_entry (TAG_NONE, SET_DBF_VPN_OUT)
              - recorded_entry (TAG_NONE, SET_DBF_VPN_IN)

The two debug SETs are not returned by
NetworkStatsService.openSession(). These debug entries are
retrieved by NetworkStatsCollection.dump().

Bug: 19536273
Change-Id: I03ef9f7667f5f2f48cbe3f6b11447fe7ead8ad3b

2 files changed, 66 insertions, 6 deletions

diff --git a/core/java/android/net/NetworkStats.java b/core/java/android/net/NetworkStats.java
index 0766253..77d7e0c 100644
--- a/core/java/android/net/NetworkStats.java
+++ b/core/java/android/net/NetworkStats.java
@@ -50,12 +50,19 @@ public class NetworkStats implements Parcelable {
     public static final int UID_ALL = -1;
     /** {@link #tag} value matching any tag. */
     public static final int TAG_ALL = -1;
-    /** {@link #set} value when all sets combined. */
+    /** {@link #set} value when all sets combined, not including debug sets. */
     public static final int SET_ALL = -1;
     /** {@link #set} value where background data is accounted. */
     public static final int SET_DEFAULT = 0;
     /** {@link #set} value where foreground data is accounted. */
     public static final int SET_FOREGROUND = 1;
+    /** All {@link #set} value greater than SET_DEBUG_START are debug {@link #set} values. */
+    public static final int SET_DEBUG_START = 1000;
+    /** Debug {@link #set} value when the VPN stats are moved in. */
+    public static final int SET_DBG_VPN_IN = 1001;
+    /** Debug {@link #set} value when the VPN stats are moved out of a vpn UID. */
+    public static final int SET_DBG_VPN_OUT = 1002;
+
     /** {@link #tag} value for total data across all tags. */
     public static final int TAG_NONE = 0;
 
@@ -729,6 +736,10 @@ public class NetworkStats implements Parcelable {
                 return "DEFAULT";
             case SET_FOREGROUND:
                 return "FOREGROUND";
+            case SET_DBG_VPN_IN:
+                return "DBG_VPN_IN";
+            case SET_DBG_VPN_OUT:
+                return "DBG_VPN_OUT";
             default:
                 return "UNKNOWN";
         }
@@ -745,12 +756,27 @@ public class NetworkStats implements Parcelable {
                 return "def";
             case SET_FOREGROUND:
                 return "fg";
+            case SET_DBG_VPN_IN:
+                return "vpnin";
+            case SET_DBG_VPN_OUT:
+                return "vpnout";
             default:
                 return "unk";
         }
     }
 
     /**
+     * @return true if the querySet matches the dataSet.
+     */
+    public static boolean setMatches(int querySet, int dataSet) {
+        if (querySet == dataSet) {
+            return true;
+        }
+        // SET_ALL matches all non-debugging sets.
+        return querySet == SET_ALL && dataSet < SET_DEBUG_START;
+    }
+
+    /**
      * Return text description of {@link #tag} value.
      */
     public static String tagToString(int tag) {
@@ -843,6 +869,9 @@ public class NetworkStats implements Parcelable {
             if (recycle.uid == UID_ALL) {
                 throw new IllegalStateException(
                         "Cannot adjust VPN accounting on an iface aggregated NetworkStats.");
+            } if (recycle.set == SET_DBG_VPN_IN || recycle.set == SET_DBG_VPN_OUT) {
+                throw new IllegalStateException(
+                        "Cannot adjust VPN accounting on a NetworkStats containing SET_DBG_VPN_*");
             }
 
             if (recycle.uid == tunUid && recycle.tag == TAG_NONE
@@ -906,6 +935,9 @@ public class NetworkStats implements Parcelable {
                 combineValues(tmpEntry);
                 if (tag[i] == TAG_NONE) {
                     moved.add(tmpEntry);
+                    // Add debug info
+                    tmpEntry.set = SET_DBG_VPN_IN;
+                    combineValues(tmpEntry);
                 }
             }
         }
@@ -913,6 +945,13 @@ public class NetworkStats implements Parcelable {
     }
 
     private void deductTrafficFromVpnApp(int tunUid, String underlyingIface, Entry moved) {
+        // Add debug info
+        moved.uid = tunUid;
+        moved.set = SET_DBG_VPN_OUT;
+        moved.tag = TAG_NONE;
+        moved.iface = underlyingIface;
+        combineValues(moved);
+
         // Caveat: if the vpn software uses tag, the total tagged traffic may be greater than
         // the TAG_NONE traffic.
         int idxVpnBackground = findIndex(underlyingIface, tunUid, SET_DEFAULT, TAG_NONE);
diff --git a/core/tests/coretests/src/android/net/NetworkStatsTest.java b/core/tests/coretests/src/android/net/NetworkStatsTest.java
index fd922a2..a470de1 100644
--- a/core/tests/coretests/src/android/net/NetworkStatsTest.java
+++ b/core/tests/coretests/src/android/net/NetworkStatsTest.java
@@ -18,6 +18,8 @@ package android.net;
 
 import static android.net.NetworkStats.SET_DEFAULT;
 import static android.net.NetworkStats.SET_FOREGROUND;
+import static android.net.NetworkStats.SET_DBG_VPN_IN;
+import static android.net.NetworkStats.SET_DBG_VPN_OUT;
 import static android.net.NetworkStats.SET_ALL;
 import static android.net.NetworkStats.IFACE_ALL;
 import static android.net.NetworkStats.TAG_NONE;
@@ -346,7 +348,7 @@ public class NetworkStatsTest extends TestCase {
             .addValues(underlyingIface, tunUid, SET_FOREGROUND, TAG_NONE, 0L, 0L, 0L, 0L, 0L);
 
         assertTrue(delta.migrateTun(tunUid, tunIface, underlyingIface));
-        assertEquals(17, delta.size());
+        assertEquals(21, delta.size());
 
         // tunIface and TEST_IFACE entries are not changed.
         assertValues(delta, 0, tunIface, 10100, SET_DEFAULT, TAG_NONE,
@@ -377,14 +379,33 @@ public class NetworkStatsTest extends TestCase {
                 0L, 0L, 0L, 0L, 0L);
 
         // New entries are added for new application's underlying Iface traffic
-        assertValues(delta, 13, underlyingIface, 10120, SET_DEFAULT, TAG_NONE,
+        assertContains(delta, underlyingIface, 10120, SET_DEFAULT, TAG_NONE,
                 72667L, 197L, 41872l, 219L, 0L);
-        assertValues(delta, 14, underlyingIface, 10120, SET_FOREGROUND, TAG_NONE,
+        assertContains(delta, underlyingIface, 10120, SET_FOREGROUND, TAG_NONE,
                 9297L, 17L, 3936, 19L, 0L);
-        assertValues(delta, 15, underlyingIface, 10120, SET_DEFAULT, testTag1,
+        assertContains(delta, underlyingIface, 10120, SET_DEFAULT, testTag1,
                 21691L, 41L, 13179L, 46L, 0L);
-        assertValues(delta, 16, underlyingIface, 10120, SET_FOREGROUND, testTag1,
+        assertContains(delta, underlyingIface, 10120, SET_FOREGROUND, testTag1,
                 1281L, 2L, 634L, 1L, 0L);
+
+        // New entries are added for debug purpose
+        assertContains(delta, underlyingIface, 10100, SET_DBG_VPN_IN, TAG_NONE,
+                39605L, 46L, 11690, 49, 0);
+        assertContains(delta, underlyingIface, 10120, SET_DBG_VPN_IN, TAG_NONE,
+                81964, 214, 45808, 238, 0);
+        assertContains(delta, underlyingIface, tunUid, SET_DBG_VPN_IN, TAG_NONE,
+                4983, 10, 1717, 10, 0);
+        assertContains(delta, underlyingIface, tunUid, SET_DBG_VPN_OUT, TAG_NONE,
+                126552, 270, 59215, 297, 0);
+
+    }
+
+    private static void assertContains(NetworkStats stats,  String iface, int uid, int set,
+            int tag, long rxBytes, long rxPackets, long txBytes, long txPackets, long operations) {
+        int index = stats.findIndex(iface, uid, set, tag);
+        assertTrue(index != -1);
+        assertValues(stats, index, iface, uid, set, tag,
+                rxBytes, rxPackets, txBytes, txPackets, operations);
     }
 
     private static void assertValues(NetworkStats stats, int index, String iface, int uid, int set,