Change TrafficStats to a new JNI implementation.

Also change phone's ConnectionStateTrackers to use it directly,
rather than through the INetStat binder interface.

Bug: 2578938
Change-Id: I8858e2609cbec3be845a0ce5178cb03f67e01b41

core/java/android/net/TrafficStats.java

@@ -23,12 +23,12 @@ import java.io.RandomAccessFile;
 import java.io.IOException;
 
 /**
- * Class that provides network traffic statistics.  These statistics include bytes transmitted and
+ * Class that provides network traffic statistics.  These statistics include
- * received and network packets transmitted and received, over all interfaces, over the mobile
+ * bytes transmitted and received and network packets transmitted and received,
- * interface, and on a per-UID basis.
+ * over all interfaces, over the mobile interface, and on a per-UID basis.
  * <p>
- * These statistics may not be available on all platforms.  If the statistics are not supported
+ * These statistics may not be available on all platforms.  If the statistics
- * by this device, {@link #UNSUPPORTED} will be returned.
+ * are not supported by this device, {@link #UNSUPPORTED} will be returned.
  */
 public class TrafficStats {
     /**
@@ -36,27 +36,13 @@ public class TrafficStats {
      */
     public final static int UNSUPPORTED = -1;
 
-    // Logging tag.
-    private final static String TAG = "trafficstats";
-
-    // We pre-create all the File objects so we don't spend a lot of
-    // CPU at runtime converting from Java Strings to byte[] for the
-    // kernel calls.
-    private final static File[] MOBILE_TX_PACKETS = mobileFiles("tx_packets");
-    private final static File[] MOBILE_RX_PACKETS = mobileFiles("rx_packets");
-    private final static File[] MOBILE_TX_BYTES = mobileFiles("tx_bytes");
-    private final static File[] MOBILE_RX_BYTES = mobileFiles("rx_bytes");
-    private final static File SYS_CLASS_NET_DIR = new File("/sys/class/net");
-
     /**
      * Get the total number of packets transmitted through the mobile interface.
      *
      * @return number of packets.  If the statistics are not supported by this device,
      * {@link #UNSUPPORTED} will be returned.
      */
-    public static long getMobileTxPackets() {
+    public static native long getMobileTxPackets();
-        return getMobileStat(MOBILE_TX_PACKETS);
-    }
 
     /**
      * Get the total number of packets received through the mobile interface.
@@ -64,9 +50,7 @@ public class TrafficStats {
      * @return number of packets.  If the statistics are not supported by this device,
      * {@link #UNSUPPORTED} will be returned.
      */
-    public static long getMobileRxPackets() {
+    public static native long getMobileRxPackets();
-        return getMobileStat(MOBILE_RX_PACKETS);
-    }
 
     /**
      * Get the total number of bytes transmitted through the mobile interface.
@@ -74,9 +58,7 @@ public class TrafficStats {
      * @return number of bytes.  If the statistics are not supported by this device,
      * {@link #UNSUPPORTED} will be returned.
      */
-      public static long getMobileTxBytes() {
+      public static native long getMobileTxBytes();
-          return getMobileStat(MOBILE_TX_BYTES);
-      }
 
     /**
      * Get the total number of bytes received through the mobile interface.
@@ -84,9 +66,7 @@ public class TrafficStats {
      * @return number of bytes.  If the statistics are not supported by this device,
      * {@link #UNSUPPORTED} will be returned.
      */
-    public static long getMobileRxBytes() {
+    public static native long getMobileRxBytes();
-        return getMobileStat(MOBILE_RX_BYTES);
-    }
 
     /**
      * Get the total number of packets sent through all network interfaces.
@@ -94,9 +74,7 @@ public class TrafficStats {
      * @return the number of packets.  If the statistics are not supported by this device,
      * {@link #UNSUPPORTED} will be returned.
      */
-    public static long getTotalTxPackets() {
+    public static native long getTotalTxPackets();
-        return getTotalStat("tx_packets");
-    }
 
     /**
      * Get the total number of packets received through all network interfaces.
@@ -104,9 +82,7 @@ public class TrafficStats {
      * @return number of packets.  If the statistics are not supported by this device,
      * {@link #UNSUPPORTED} will be returned.
      */
-    public static long getTotalRxPackets() {
+    public static native long getTotalRxPackets();
-        return getTotalStat("rx_packets");
-    }
 
     /**
      * Get the total number of bytes sent through all network interfaces.
@@ -114,9 +90,7 @@ public class TrafficStats {
      * @return number of bytes.  If the statistics are not supported by this device,
      * {@link #UNSUPPORTED} will be returned.
      */
-    public static long getTotalTxBytes() {
+    public static native long getTotalTxBytes();
-        return getTotalStat("tx_bytes");
-    }
 
     /**
      * Get the total number of bytes received through all network interfaces.
@@ -124,9 +98,7 @@ public class TrafficStats {
      * @return number of bytes.  If the statistics are not supported by this device,
      * {@link #UNSUPPORTED} will be returned.
      */
-    public static long getTotalRxBytes() {
+    public static native long getTotalRxBytes();
-        return getTotalStat("rx_bytes");
-    }
 
     /**
      * Get the number of bytes sent through the network for this UID.
@@ -138,9 +110,7 @@ public class TrafficStats {
      * @return number of bytes.  If the statistics are not supported by this device,
      * {@link #UNSUPPORTED} will be returned.
      */
-    public static long getUidTxBytes(int uid) {
+    public static native long getUidTxBytes(int uid);
-        return getNumberFromFilePath("/proc/uid_stat/" + uid + "/tcp_snd");
-    }
 
     /**
      * Get the number of bytes received through the network for this UID.
@@ -151,115 +121,5 @@ public class TrafficStats {
      * @param uid The UID of the process to examine.
      * @return number of bytes
      */
-    public static long getUidRxBytes(int uid) {
+    public static native long getUidRxBytes(int uid);
-        return getNumberFromFilePath("/proc/uid_stat/" + uid + "/tcp_rcv");
-    }
-
-    /**
-     * Returns the array of two possible File locations for a given
-     * statistic.
-     */
-    private static File[] mobileFiles(String whatStat) {
-        // Note that we stat them at runtime to see which is
-        // available, rather than here, to guard against the files
-        // coming & going later as modules shut down (e.g. airplane
-        // mode) and whatnot.  The runtime stat() isn't expensive compared
-        // to the previous charset conversion that happened before we
-        // were reusing File instances.
-        File[] files = new File[2];
-        files[0] = new File("/sys/class/net/rmnet0/statistics/" + whatStat);
-        files[1] = new File("/sys/class/net/ppp0/statistics/" + whatStat);
-        return files;
-    }
-
-    private static long getTotalStat(String whatStat) {
-        File netdir = new File("/sys/class/net");
-
-        File[] nets = SYS_CLASS_NET_DIR.listFiles();
-        if (nets == null) {
-            return UNSUPPORTED;
-        }
-        long total = 0;
-        StringBuffer strbuf = new StringBuffer();
-        for (File net : nets) {
-            strbuf.append(net.getPath()).append(File.separator).append("statistics")
-                    .append(File.separator).append(whatStat);
-            total += getNumberFromFilePath(strbuf.toString());
-            strbuf.setLength(0);
-        }
-        return total;
-    }
-
-    private static long getMobileStat(File[] files) {
-        for (int i = 0; i < files.length; i++) {
-            File file = files[i];
-            if (!file.exists()) {
-                continue;
-            }
-            try {
-                RandomAccessFile raf = new RandomAccessFile(file, "r");
-                return getNumberFromFile(raf, file.getAbsolutePath());
-            } catch (IOException e) {
-                Log.w(TAG,
-                      "Exception opening TCP statistics file " + file.getAbsolutePath(),
-                      e);
-            }
-        }
-        return UNSUPPORTED;
-    }
-
-    // File will have format <number><newline>
-    private static long getNumberFromFilePath(String filename) {
-        RandomAccessFile raf = getFile(filename);
-        if (raf == null) {
-            return UNSUPPORTED;
-        }
-        return getNumberFromFile(raf, filename);
-    }
-
-    // Private buffer for getNumberFromFile.  Safe for re-use because
-    // getNumberFromFile is synchronized.
-    private final static byte[] buf = new byte[16];
-
-    private static synchronized long getNumberFromFile(RandomAccessFile raf, String filename) {
-        try {
-            raf.read(buf);
-            raf.close();
-        } catch (IOException e) {
-            Log.w(TAG, "Exception getting TCP bytes from " + filename, e);
-            return UNSUPPORTED;
-        } finally {
-            if (raf != null) {
-                try {
-                    raf.close();
-                } catch (IOException e) {
-                    Log.w(TAG, "Exception closing " + filename, e);
-                }
-            }
-        }
-
-        long num = 0L;
-        for (int i = 0; i < buf.length; i++) {
-            if (buf[i] < '0' || buf[i] > '9') {
-                break;
-            }
-            num *= 10;
-            num += buf[i] - '0';
-        }
-        return num;
-    }
-
-    private static RandomAccessFile getFile(String filename) {
-        File f = new File(filename);
-        if (!f.canRead()) {
-            return null;
-        }
-
-        try {
-            return new RandomAccessFile(f, "r");
-        } catch (IOException e) {
-            Log.w(TAG, "Exception opening TCP statistics file " + filename, e);
-            return null;
-        }
-    }
 }

core/jni/android_net_TrafficStats.cpp

@@ -0,0 +1,165 @@
+/*
+ * Copyright (C) 2010 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.
+ */
+
+#define LOG_TAG "TrafficStats"
+
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include <android_runtime/AndroidRuntime.h>
+#include <cutils/logger.h>
+#include <jni.h>
+#include <utils/misc.h>
+#include <utils/Log.h>
+
+namespace android {
+
+// Returns an ASCII decimal number read from the specified file, -1 on error.
+static jlong readNumber(char const* filename) {
+    char buf[80];
+    int fd = open(filename, O_RDONLY);
+    if (fd < 0) {
+        if (errno != ENOENT) LOGE("Can't open %s: %s", filename, strerror(errno));
+        return -1;
+    }
+
+    int len = read(fd, buf, sizeof(buf) - 1);
+    if (len < 0) {
+        LOGE("Can't read %s: %s", filename, strerror(errno));
+        close(fd);
+        return -1;
+    }
+
+    close(fd);
+    buf[len] = '\0';
+    return atoll(buf);
+}
+
+// Return the number from the first file which exists and contains data
+static jlong tryBoth(char const* a, char const* b) {
+    jlong num = readNumber(a);
+    return num >= 0 ? num : readNumber(b);
+}
+
+// Returns the sum of numbers from the specified path under /sys/class/net/*,
+// -1 if no such file exists.
+static jlong readTotal(char const* suffix) {
+    char filename[PATH_MAX] = "/sys/class/net/";
+    DIR *dir = opendir(filename);
+    if (dir == NULL) {
+        LOGE("Can't list %s: %s", filename, strerror(errno));
+        return -1;
+    }
+
+    int len = strlen(filename);
+    jlong total = -1;
+    while (struct dirent *entry = readdir(dir)) {
+        // Skip ., .., and localhost interfaces.
+        if (entry->d_name[0] != '.' && strncmp(entry->d_name, "lo", 2) != 0) {
+            strlcpy(filename + len, entry->d_name, sizeof(filename) - len);
+            strlcat(filename, suffix, sizeof(filename));
+            jlong num = readNumber(filename);
+            if (num >= 0) total = total < 0 ? num : total + num;
+        }
+    }
+
+    closedir(dir);
+    return total;
+}
+
+// Mobile stats get accessed a lot more often than total stats.
+// Note the individual files can come and go at runtime, so we check
+// each file every time (rather than caching which ones exist).
+
+static jlong getMobileTxPackets(JNIEnv* env, jobject clazz) {
+    return tryBoth(
+            "/sys/class/net/rmnet0/statistics/tx_packets",
+            "/sys/class/net/ppp0/statistics/tx_packets");
+}
+
+static jlong getMobileRxPackets(JNIEnv* env, jobject clazz) {
+    return tryBoth(
+            "/sys/class/net/rmnet0/statistics/rx_packets",
+            "/sys/class/net/ppp0/statistics/rx_packets");
+}
+
+static jlong getMobileTxBytes(JNIEnv* env, jobject clazz) {
+    return tryBoth(
+            "/sys/class/net/rmnet0/statistics/tx_bytes",
+            "/sys/class/net/ppp0/statistics/tx_bytes");
+}
+
+static jlong getMobileRxBytes(JNIEnv* env, jobject clazz) {
+    return tryBoth(
+            "/sys/class/net/rmnet0/statistics/rx_bytes",
+            "/sys/class/net/ppp0/statistics/rx_bytes");
+}
+
+// Total stats are read less often, so we're willing to put up
+// with listing the directory and concatenating filenames.
+
+static jlong getTotalTxPackets(JNIEnv* env, jobject clazz) {
+    return readTotal("/statistics/tx_packets");
+}
+
+static jlong getTotalRxPackets(JNIEnv* env, jobject clazz) {
+    return readTotal("/statistics/rx_packets");
+}
+
+static jlong getTotalTxBytes(JNIEnv* env, jobject clazz) {
+    return readTotal("/statistics/tx_bytes");
+}
+
+static jlong getTotalRxBytes(JNIEnv* env, jobject clazz) {
+    return readTotal("/statistics/rx_bytes");
+}
+
+// Per-UID stats require reading from a constructed filename.
+
+static jlong getUidRxBytes(JNIEnv* env, jobject clazz, jint uid) {
+    char filename[80];
+    sprintf(filename, "/proc/uid_stat/%d/tcp_rcv", uid);
+    return readNumber(filename);
+}
+
+static jlong getUidTxBytes(JNIEnv* env, jobject clazz, jint uid) {
+    char filename[80];
+    sprintf(filename, "/proc/uid_stat/%d/tcp_snd", uid);
+    return readNumber(filename);
+}
+
+static JNINativeMethod gMethods[] = {
+    {"getMobileTxPackets", "()J", (void*) getMobileTxPackets},
+    {"getMobileRxPackets", "()J", (void*) getMobileRxPackets},
+    {"getMobileTxBytes", "()J", (void*) getMobileTxBytes},
+    {"getMobileRxBytes", "()J", (void*) getMobileRxBytes},
+    {"getTotalTxPackets", "()J", (void*) getTotalTxPackets},
+    {"getTotalRxPackets", "()J", (void*) getTotalRxPackets},
+    {"getTotalTxBytes", "()J", (void*) getTotalTxBytes},
+    {"getTotalRxBytes", "()J", (void*) getTotalRxBytes},
+    {"getUidTxBytes", "(I)J", (void*) getUidTxBytes},
+    {"getUidRxBytes", "(I)J", (void*) getUidRxBytes},
+};
+
+int register_android_net_TrafficStats(JNIEnv* env) {
+    return AndroidRuntime::registerNativeMethods(env, "android/net/TrafficStats",
+            gMethods, NELEM(gMethods));
+}
+
+}