1 files changed, 102 insertions, 0 deletions
diff --git a/tunnel/src/main/java/com/wireguard/android/backend/Statistics.java b/tunnel/src/main/java/com/wireguard/android/backend/Statistics.java
new file mode 100644
index 00000000..08b84949
--- /dev/null
+++ b/tunnel/src/main/java/com/wireguard/android/backend/Statistics.java
@@ -0,0 +1,102 @@
+/*
+ * Copyright © 2017-2023 WireGuard LLC. All Rights Reserved.
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package com.wireguard.android.backend;
+
+import android.os.SystemClock;
+
+import com.wireguard.crypto.Key;
+import com.wireguard.util.NonNullForAll;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+
+import androidx.annotation.Nullable;
+
+/**
+ * Class representing transfer statistics for a {@link Tunnel} instance.
+ */
+@NonNullForAll
+public class Statistics {
+    public record PeerStats(long rxBytes, long txBytes, long latestHandshakeEpochMillis) { }
+    private final Map<Key, PeerStats> stats = new HashMap<>();
+    private long lastTouched = SystemClock.elapsedRealtime();
+
+    Statistics() {
+    }
+
+    /**
+     * Add a peer and its current stats to the internal map.
+     *
+     * @param key               A WireGuard public key bound to a particular peer
+     * @param rxBytes           The received traffic for the {@link com.wireguard.config.Peer} referenced by
+     *                          the provided {@link Key}. This value is in bytes
+     * @param txBytes           The transmitted traffic for the {@link com.wireguard.config.Peer} referenced by
+     *                          the provided {@link Key}. This value is in bytes.
+     * @param latestHandshake   The timestamp of the latest handshake for the {@link com.wireguard.config.Peer}
+     *                          referenced by the provided {@link Key}. The value is in epoch milliseconds.
+     */
+    void add(final Key key, final long rxBytes, final long txBytes, final long latestHandshake) {
+        stats.put(key, new PeerStats(rxBytes, txBytes, latestHandshake));
+        lastTouched = SystemClock.elapsedRealtime();
+    }
+
+    /**
+     * Check if the statistics are stale, indicating the need for the {@link Backend} to update them.
+     *
+     * @return boolean indicating if the current statistics instance has stale values.
+     */
+    public boolean isStale() {
+        return SystemClock.elapsedRealtime() - lastTouched > 900;
+    }
+
+    /**
+     * Get the statistics for the {@link com.wireguard.config.Peer} referenced by the provided {@link Key}
+     *
+     * @param peer A {@link Key} representing a {@link com.wireguard.config.Peer}.
+     * @return a {@link PeerStats} representing various statistics about this peer.
+     */
+    @Nullable
+    public PeerStats peer(final Key peer) {
+        return stats.get(peer);
+    }
+
+    /**
+     * Get the list of peers being tracked by this instance.
+     *
+     * @return An array of {@link Key} instances representing WireGuard
+     * {@link com.wireguard.config.Peer}s
+     */
+    public Key[] peers() {
+        return stats.keySet().toArray(new Key[0]);
+    }
+
+    /**
+     * Get the total received traffic by all the peers being tracked by this instance
+     *
+     * @return a long representing the number of bytes received by the peers being tracked.
+     */
+    public long totalRx() {
+        long rx = 0;
+        for (final PeerStats val : stats.values()) {
+            rx += val.rxBytes;
+        }
+        return rx;
+    }
+
+    /**
+     * Get the total transmitted traffic by all the peers being tracked by this instance
+     *
+     * @return a long representing the number of bytes transmitted by the peers being tracked.
+     */
+    public long totalTx() {
+        long tx = 0;
+        for (final PeerStats val : stats.values()) {
+            tx += val.txBytes;
+        }
+        return tx;
+    }
+}