Simplify tethering active session counting
The previous implementation for tracking tethering active sessions
was overly complex. This commit simplifies the logic by:
- Moving the counting to the BpfCoordinatorShimImpl (31 impl)
where rule addition and deletion are centralized.
- Eliminating the unnecessary Android version check (S+) as
the 31 shim only runs on S+.
- Relocating the tracking counters from
ConntrackEventConsumer to the shim class, improving code
locality and encapsulation.
This change addresses the feedback from the networking mainline
release council and resolves a release blocker.
Test: atest TetheringTests:com.android.networkstack.tethering.BpfCoordinatorTest
Fix: 370652384
Change-Id: I70ca58fc45694c738745d7a872272641a62551fd
diff --git a/Tethering/apishim/30/com/android/networkstack/tethering/apishim/api30/BpfCoordinatorShimImpl.java b/Tethering/apishim/30/com/android/networkstack/tethering/apishim/api30/BpfCoordinatorShimImpl.java
index 0df9047..af061e4 100644
--- a/Tethering/apishim/30/com/android/networkstack/tethering/apishim/api30/BpfCoordinatorShimImpl.java
+++ b/Tethering/apishim/30/com/android/networkstack/tethering/apishim/api30/BpfCoordinatorShimImpl.java
@@ -198,4 +198,13 @@
public String toString() {
return "Netd used";
}
+
+ @Override
+ public int getLastMaxConnectionAndResetToCurrent() {
+ return 0;
+ }
+
+ @Override
+ public void clearConnectionCounters() {
+ }
}
diff --git a/Tethering/apishim/31/com/android/networkstack/tethering/apishim/api31/BpfCoordinatorShimImpl.java b/Tethering/apishim/31/com/android/networkstack/tethering/apishim/api31/BpfCoordinatorShimImpl.java
index e6e99f4..b460f0d 100644
--- a/Tethering/apishim/31/com/android/networkstack/tethering/apishim/api31/BpfCoordinatorShimImpl.java
+++ b/Tethering/apishim/31/com/android/networkstack/tethering/apishim/api31/BpfCoordinatorShimImpl.java
@@ -19,6 +19,7 @@
import static android.net.netstats.provider.NetworkStatsProvider.QUOTA_UNLIMITED;
import static com.android.net.module.util.NetworkStackConstants.RFC7421_PREFIX_LENGTH;
+import static com.android.networkstack.tethering.TetheringConfiguration.TETHER_ACTIVE_SESSIONS_METRICS;
import android.system.ErrnoException;
import android.system.Os;
@@ -108,6 +109,22 @@
// TODO: Add IPv6 rule count.
private final SparseArray<Integer> mRule4CountOnUpstream = new SparseArray<>();
+ private final boolean mSupportActiveSessionsMetrics;
+ /**
+ * Tracks the current number of tethering connections and the maximum
+ * observed since the last metrics collection. Used to provide insights
+ * into the distribution of active tethering sessions for metrics reporting.
+
+ * These variables are accessed on the handler thread, which includes:
+ * 1. ConntrackEvents signaling the addition or removal of an IPv4 rule.
+ * 2. ConntrackEvents indicating the removal of a tethering client,
+ * triggering the removal of associated rules.
+ * 3. Removal of the last IpServer, which resets counters to handle
+ * potential synchronization issues.
+ */
+ private int mLastMaxConnectionCount = 0;
+ private int mCurrentConnectionCount = 0;
+
public BpfCoordinatorShimImpl(@NonNull final Dependencies deps) {
mLog = deps.getSharedLog().forSubComponent(TAG);
@@ -156,6 +173,9 @@
} catch (ErrnoException e) {
mLog.e("Could not clear mBpfDevMap: " + e);
}
+
+ mSupportActiveSessionsMetrics = deps.isFeatureEnabled(deps.getContext(),
+ TETHER_ACTIVE_SESSIONS_METRICS);
}
@Override
@@ -350,6 +370,12 @@
final int upstreamIfindex = (int) key.iif;
int count = mRule4CountOnUpstream.get(upstreamIfindex, 0 /* default */);
mRule4CountOnUpstream.put(upstreamIfindex, ++count);
+
+ if (mSupportActiveSessionsMetrics) {
+ mCurrentConnectionCount++;
+ mLastMaxConnectionCount = Math.max(mCurrentConnectionCount,
+ mLastMaxConnectionCount);
+ }
} else {
mBpfUpstream4Map.insertEntry(key, value);
}
@@ -385,6 +411,10 @@
} else {
mRule4CountOnUpstream.put(upstreamIfindex, count);
}
+
+ if (mSupportActiveSessionsMetrics) {
+ mCurrentConnectionCount--;
+ }
} else {
if (!mBpfUpstream4Map.deleteEntry(key)) return false; // Rule did not exist
}
@@ -465,14 +495,16 @@
@Override
public String toString() {
- return String.join(", ", new String[] {
- mapStatus(mBpfDownstream6Map, "mBpfDownstream6Map"),
- mapStatus(mBpfUpstream6Map, "mBpfUpstream6Map"),
- mapStatus(mBpfDownstream4Map, "mBpfDownstream4Map"),
- mapStatus(mBpfUpstream4Map, "mBpfUpstream4Map"),
- mapStatus(mBpfStatsMap, "mBpfStatsMap"),
- mapStatus(mBpfLimitMap, "mBpfLimitMap"),
- mapStatus(mBpfDevMap, "mBpfDevMap")
+ return String.join(", ", new String[]{
+ mapStatus(mBpfDownstream6Map, "mBpfDownstream6Map"),
+ mapStatus(mBpfUpstream6Map, "mBpfUpstream6Map"),
+ mapStatus(mBpfDownstream4Map, "mBpfDownstream4Map"),
+ mapStatus(mBpfUpstream4Map, "mBpfUpstream4Map"),
+ mapStatus(mBpfStatsMap, "mBpfStatsMap"),
+ mapStatus(mBpfLimitMap, "mBpfLimitMap"),
+ mapStatus(mBpfDevMap, "mBpfDevMap"),
+ "mCurrentConnectionCount=" + mCurrentConnectionCount,
+ "mLastMaxConnectionCount=" + mLastMaxConnectionCount
});
}
@@ -507,4 +539,17 @@
return 0;
}
+
+ /** Get last max connection count and reset to current count. */
+ public int getLastMaxConnectionAndResetToCurrent() {
+ final int ret = mLastMaxConnectionCount;
+ mLastMaxConnectionCount = mCurrentConnectionCount;
+ return ret;
+ }
+
+ /** Clear current connection count. */
+ public void clearConnectionCounters() {
+ mCurrentConnectionCount = 0;
+ mLastMaxConnectionCount = 0;
+ }
}
diff --git a/Tethering/apishim/common/com/android/networkstack/tethering/apishim/common/BpfCoordinatorShim.java b/Tethering/apishim/common/com/android/networkstack/tethering/apishim/common/BpfCoordinatorShim.java
index 026b1c3..cb8bcc9 100644
--- a/Tethering/apishim/common/com/android/networkstack/tethering/apishim/common/BpfCoordinatorShim.java
+++ b/Tethering/apishim/common/com/android/networkstack/tethering/apishim/common/BpfCoordinatorShim.java
@@ -202,5 +202,11 @@
* Remove interface index mapping.
*/
public abstract boolean removeDevMap(int ifIndex);
+
+ /** Get last max connection count and reset to current count. */
+ public abstract int getLastMaxConnectionAndResetToCurrent();
+
+ /** Clear current connection count. */
+ public abstract void clearConnectionCounters();
}
diff --git a/Tethering/src/com/android/networkstack/tethering/BpfCoordinator.java b/Tethering/src/com/android/networkstack/tethering/BpfCoordinator.java
index 89e06da..75ab9ec 100644
--- a/Tethering/src/com/android/networkstack/tethering/BpfCoordinator.java
+++ b/Tethering/src/com/android/networkstack/tethering/BpfCoordinator.java
@@ -27,6 +27,7 @@
import static android.system.OsConstants.ETH_P_IP;
import static android.system.OsConstants.ETH_P_IPV6;
+import static com.android.internal.annotations.VisibleForTesting.Visibility.PRIVATE;
import static com.android.net.module.util.NetworkStackConstants.IPV4_MIN_MTU;
import static com.android.net.module.util.NetworkStackConstants.IPV6_ADDR_LEN;
import static com.android.net.module.util.ip.ConntrackMonitor.ConntrackEvent;
@@ -334,7 +335,6 @@
};
// TODO: add BpfMap<TetherDownstream64Key, TetherDownstream64Value> retrieving function.
- @VisibleForTesting
public abstract static class Dependencies {
/** Get handler. */
@NonNull public abstract Handler getHandler();
@@ -585,14 +585,10 @@
if (mHandler.hasCallbacks(mScheduledConntrackMetricsSampling)) {
mHandler.removeCallbacks(mScheduledConntrackMetricsSampling);
}
- final int currentCount = mBpfConntrackEventConsumer.getCurrentConnectionCount();
- if (currentCount != 0) {
- Log.wtf(TAG, "Unexpected CurrentConnectionCount: " + currentCount);
- }
// Avoid sending metrics when tethering is about to close.
// This leads to a missing final sample before disconnect
// but avoids possibly duplicating the last metric in the upload.
- mBpfConntrackEventConsumer.clearConnectionCounters();
+ mBpfCoordinatorShim.clearConnectionCounters();
}
// Stop scheduled polling stats and poll the latest stats from BPF maps.
if (mHandler.hasCallbacks(mScheduledPollingStats)) {
@@ -1091,10 +1087,6 @@
for (final Tether4Key k : deleteDownstreamRuleKeys) {
mBpfCoordinatorShim.tetherOffloadRuleRemove(DOWNSTREAM, k);
}
- if (mSupportActiveSessionsMetrics) {
- mBpfConntrackEventConsumer.decreaseCurrentConnectionCount(
- deleteUpstreamRuleKeys.size());
- }
// Cleanup each upstream interface by a set which avoids duplicated work on the same
// upstream interface. Cleaning up the same interface twice (or more) here may raise
@@ -1367,10 +1359,6 @@
pw.println();
pw.println("mSupportActiveSessionsMetrics: " + mSupportActiveSessionsMetrics);
- pw.println("getLastMaxConnectionCount: "
- + mBpfConntrackEventConsumer.getLastMaxConnectionCount());
- pw.println("getCurrentConnectionCount: "
- + mBpfConntrackEventConsumer.getCurrentConnectionCount());
}
private void dumpStats(@NonNull IndentingPrintWriter pw) {
@@ -2062,21 +2050,6 @@
// while TCP status is established.
@VisibleForTesting
class BpfConntrackEventConsumer implements ConntrackEventConsumer {
- /**
- * Tracks the current number of tethering connections and the maximum
- * observed since the last metrics collection. Used to provide insights
- * into the distribution of active tethering sessions for metrics reporting.
-
- * These variables are accessed on the handler thread, which includes:
- * 1. ConntrackEvents signaling the addition or removal of an IPv4 rule.
- * 2. ConntrackEvents indicating the removal of a tethering client,
- * triggering the removal of associated rules.
- * 3. Removal of the last IpServer, which resets counters to handle
- * potential synchronization issues.
- */
- private int mLastMaxConnectionCount = 0;
- private int mCurrentConnectionCount = 0;
-
// The upstream4 and downstream4 rules are built as the following tables. Only raw ip
// upstream interface is supported. Note that the field "lastUsed" is only updated by
// BPF program which records the last used time for a given rule.
@@ -2210,10 +2183,6 @@
return;
}
- if (mSupportActiveSessionsMetrics) {
- decreaseCurrentConnectionCount(1);
- }
-
maybeClearLimit(upstreamIndex);
return;
}
@@ -2237,40 +2206,12 @@
+ ", downstream: " + addedDownstream + ")");
return;
}
- if (mSupportActiveSessionsMetrics && addedUpstream && addedDownstream) {
- mCurrentConnectionCount++;
- mLastMaxConnectionCount = Math.max(mCurrentConnectionCount,
- mLastMaxConnectionCount);
- }
}
+ }
- public int getLastMaxConnectionAndResetToCurrent() {
- final int ret = mLastMaxConnectionCount;
- mLastMaxConnectionCount = mCurrentConnectionCount;
- return ret;
- }
-
- /** For dumping current state only. */
- public int getLastMaxConnectionCount() {
- return mLastMaxConnectionCount;
- }
-
- public int getCurrentConnectionCount() {
- return mCurrentConnectionCount;
- }
-
- public void decreaseCurrentConnectionCount(int count) {
- mCurrentConnectionCount -= count;
- if (mCurrentConnectionCount < 0) {
- Log.wtf(TAG, "Unexpected mCurrentConnectionCount: "
- + mCurrentConnectionCount);
- }
- }
-
- public void clearConnectionCounters() {
- mCurrentConnectionCount = 0;
- mLastMaxConnectionCount = 0;
- }
+ @VisibleForTesting(visibility = PRIVATE)
+ public int getLastMaxConnectionAndResetToCurrent() {
+ return mBpfCoordinatorShim.getLastMaxConnectionAndResetToCurrent();
}
@VisibleForTesting
@@ -2611,7 +2552,7 @@
private void uploadConntrackMetricsSample() {
mDeps.sendTetheringActiveSessionsReported(
- mBpfConntrackEventConsumer.getLastMaxConnectionAndResetToCurrent());
+ mBpfCoordinatorShim.getLastMaxConnectionAndResetToCurrent());
}
private void schedulePollingStats() {
diff --git a/Tethering/tests/unit/src/com/android/networkstack/tethering/BpfCoordinatorTest.java b/Tethering/tests/unit/src/com/android/networkstack/tethering/BpfCoordinatorTest.java
index 5d22977..dd10cc3 100644
--- a/Tethering/tests/unit/src/com/android/networkstack/tethering/BpfCoordinatorTest.java
+++ b/Tethering/tests/unit/src/com/android/networkstack/tethering/BpfCoordinatorTest.java
@@ -2032,7 +2032,7 @@
final BpfCoordinator coordinator = makeBpfCoordinator();
initBpfCoordinatorForRule4(coordinator);
resetNetdAndBpfMaps();
- assertEquals(0, mConsumer.getLastMaxConnectionAndResetToCurrent());
+ assertEquals(0, coordinator.getLastMaxConnectionAndResetToCurrent());
// Prepare add/delete rule events.
final ArrayList<ConntrackEvent> addRuleEvents = new ArrayList<>();
@@ -2049,49 +2049,44 @@
// Add rules, verify counter increases.
for (int i = 0; i < 5; i++) {
mConsumer.accept(addRuleEvents.get(i));
- assertConsumerCountersEquals(supportActiveSessionsMetrics ? i + 1 : 0);
+ assertEquals(supportActiveSessionsMetrics ? i + 1 : 0,
+ coordinator.getLastMaxConnectionAndResetToCurrent());
}
// Add the same events again should not increase the counter because
// all events are already exist.
for (final ConntrackEvent event : addRuleEvents) {
mConsumer.accept(event);
- assertConsumerCountersEquals(supportActiveSessionsMetrics ? 5 : 0);
+ assertEquals(supportActiveSessionsMetrics ? 5 : 0,
+ coordinator.getLastMaxConnectionAndResetToCurrent());
}
// Verify removing non-existent items won't change the counters.
for (int i = 5; i < 8; i++) {
mConsumer.accept(new TestConntrackEvent.Builder().setMsgType(
IPCTNL_MSG_CT_DELETE).setProto(IPPROTO_TCP).setRemotePort(i).build());
- assertConsumerCountersEquals(supportActiveSessionsMetrics ? 5 : 0);
+ assertEquals(supportActiveSessionsMetrics ? 5 : 0,
+ coordinator.getLastMaxConnectionAndResetToCurrent());
}
// Verify remove the rules decrease the counter.
// Note the max counter returns the max, so it returns the count before deleting.
for (int i = 0; i < 5; i++) {
mConsumer.accept(delRuleEvents.get(i));
- assertEquals(supportActiveSessionsMetrics ? 4 - i : 0,
- mConsumer.getCurrentConnectionCount());
- assertEquals(supportActiveSessionsMetrics ? 5 - i : 0,
- mConsumer.getLastMaxConnectionCount());
- assertEquals(supportActiveSessionsMetrics ? 5 - i : 0,
- mConsumer.getLastMaxConnectionAndResetToCurrent());
}
+ // The maximum number of rules observed is still 5.
+ assertEquals(supportActiveSessionsMetrics ? 5 : 0,
+ coordinator.getLastMaxConnectionAndResetToCurrent());
+ // After the reset, the maximum number of rules observed is 0.
+ assertEquals(0, coordinator.getLastMaxConnectionAndResetToCurrent());
// Verify remove these rules again doesn't decrease the counter.
for (int i = 0; i < 5; i++) {
mConsumer.accept(delRuleEvents.get(i));
- assertConsumerCountersEquals(0);
+ assertEquals(0, coordinator.getLastMaxConnectionAndResetToCurrent());
}
}
- // Helper method to assert all counter values inside consumer.
- private void assertConsumerCountersEquals(int expectedCount) {
- assertEquals(expectedCount, mConsumer.getCurrentConnectionCount());
- assertEquals(expectedCount, mConsumer.getLastMaxConnectionCount());
- assertEquals(expectedCount, mConsumer.getLastMaxConnectionAndResetToCurrent());
- }
-
@FeatureFlag(name = TETHER_ACTIVE_SESSIONS_METRICS)
// BPF IPv4 forwarding only supports on S+.
@IgnoreUpTo(Build.VERSION_CODES.R)
@@ -2121,7 +2116,7 @@
coordinator.tetherOffloadClientAdd(mIpServer, clientB);
assertClientInfoExists(mIpServer, clientA);
assertClientInfoExists(mIpServer, clientB);
- assertEquals(0, mConsumer.getLastMaxConnectionAndResetToCurrent());
+ assertEquals(0, coordinator.getLastMaxConnectionAndResetToCurrent());
// Add some rules for both clients.
final int addr1RuleCount = 5;
@@ -2145,31 +2140,24 @@
.build());
}
- assertConsumerCountersEquals(
- supportActiveSessionsMetrics ? addr1RuleCount + addr2RuleCount : 0);
+ assertEquals(supportActiveSessionsMetrics ? addr1RuleCount + addr2RuleCount : 0,
+ coordinator.getLastMaxConnectionAndResetToCurrent());
// Remove 1 client. Since the 1st poll will return the LastMaxCounter and
- // update it to the current, the max counter will be kept at 1st poll, while
- // the current counter reflect the rule decreasing.
+ // update it to the current, the max counter will be kept at 1st poll.
coordinator.tetherOffloadClientRemove(mIpServer, clientA);
+ assertEquals(supportActiveSessionsMetrics ? addr1RuleCount + addr2RuleCount : 0,
+ coordinator.getLastMaxConnectionAndResetToCurrent());
+ // And the counter be updated at 2nd poll.
assertEquals(supportActiveSessionsMetrics ? addr2RuleCount : 0,
- mConsumer.getCurrentConnectionCount());
- assertEquals(supportActiveSessionsMetrics ? addr1RuleCount + addr2RuleCount : 0,
- mConsumer.getLastMaxConnectionCount());
- assertEquals(supportActiveSessionsMetrics ? addr1RuleCount + addr2RuleCount : 0,
- mConsumer.getLastMaxConnectionAndResetToCurrent());
- // And all counters be updated at 2nd poll.
- assertConsumerCountersEquals(supportActiveSessionsMetrics ? addr2RuleCount : 0);
+ coordinator.getLastMaxConnectionAndResetToCurrent());
// Remove other client.
coordinator.tetherOffloadClientRemove(mIpServer, clientB);
- assertEquals(0, mConsumer.getCurrentConnectionCount());
assertEquals(supportActiveSessionsMetrics ? addr2RuleCount : 0,
- mConsumer.getLastMaxConnectionCount());
- assertEquals(supportActiveSessionsMetrics ? addr2RuleCount : 0,
- mConsumer.getLastMaxConnectionAndResetToCurrent());
- // All counters reach zero at 2nd poll.
- assertConsumerCountersEquals(0);
+ coordinator.getLastMaxConnectionAndResetToCurrent());
+ // Verify the counter reach zero at 2nd poll.
+ assertEquals(0, coordinator.getLastMaxConnectionAndResetToCurrent());
}
@FeatureFlag(name = TETHER_ACTIVE_SESSIONS_METRICS)
@@ -2191,7 +2179,7 @@
final BpfCoordinator coordinator = makeBpfCoordinator();
initBpfCoordinatorForRule4(coordinator);
resetNetdAndBpfMaps();
- assertConsumerCountersEquals(0);
+ assertEquals(0, coordinator.getLastMaxConnectionAndResetToCurrent());
// Prepare the counter value.
for (int i = 0; i < 5; i++) {