BpfMap: wrap native fd with ParcelFileDescriptor to avoid fd leak
ParcelFileDescriptor has implemented finalize(). Wrap native fd into
ParcelFileDescriptor which helps to release fd automatically.
Bug: 230880517
Test: manual test
Steps:
1. Connect to IPv6 only wifi and clat maps are created
$ adb shell cmd wifi set-wifi-enabled enabled
05-12 13:53:41.182 1793 2031 W BpfMap : open /sys/fs/bpf/net_shared/map_clatd_clat_ingress6_map..: 493
05-12 13:53:41.182 1793 2031 W BpfMap : open /sys/fs/bpf/net_shared/map_clatd_clat_egress4_map..: 546
$ adb shell ls -all proc/1793/fd | grep bpf
.. system system 64 2022-05-12 13:55:35 .. 493 -> anon_inode:bpf-map
.. system system 64 2022-05-12 13:55:35 .. 546 -> anon_inode:bpf-map
$ adb shell dumpsys connectivity
Forwarding rules:
BPF ingress map: iif nat64Prefix v6Addr -> v4Addr oif
47 /64:ff9b::/96 /2a00:79e1:abc:6f02:6efd:1d4b:f05e:25bd -> /192.0.0.4 54
BPF egress map: iif v4Addr -> v6Addr nat64Prefix oif
54 /192.0.0.4 -> /2a00:79e1:abc:6f02:6efd:1d4b:f05e:25bd /64:ff9b::/96 47 ether
2. Disconnect from IPv6 only wifi, force GC and clat map fds are released
$ adb shell cmd wifi set-wifi-enabled disabled
$ adb shell kill -10 1793
$ adb shell ls -all proc/1793/fd | grep bpf
(fd 493 and 546 are removed)
Change-Id: I26bbafbd73eccab6f4ae2c71690ecad12bbef7df
diff --git a/staticlibs/device/com/android/net/module/util/BpfMap.java b/staticlibs/device/com/android/net/module/util/BpfMap.java
index f1420c2..0ee862a 100644
--- a/staticlibs/device/com/android/net/module/util/BpfMap.java
+++ b/staticlibs/device/com/android/net/module/util/BpfMap.java
@@ -18,6 +18,7 @@
import static android.system.OsConstants.EEXIST;
import static android.system.OsConstants.ENOENT;
+import android.os.ParcelFileDescriptor;
import android.system.ErrnoException;
import androidx.annotation.NonNull;
@@ -26,6 +27,7 @@
import com.android.net.module.util.Struct;
+import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.util.NoSuchElementException;
@@ -57,7 +59,7 @@
private static final int BPF_NOEXIST = 1;
private static final int BPF_EXIST = 2;
- private final int mMapFd;
+ private final ParcelFileDescriptor mMapFd;
private final Class<K> mKeyClass;
private final Class<V> mValueClass;
private final int mKeySize;
@@ -72,8 +74,7 @@
*/
public BpfMap(@NonNull final String path, final int flag, final Class<K> key,
final Class<V> value) throws ErrnoException, NullPointerException {
- mMapFd = bpfFdGet(path, flag);
-
+ mMapFd = ParcelFileDescriptor.adoptFd(bpfFdGet(path, flag));
mKeyClass = key;
mValueClass = value;
mKeySize = Struct.getSize(key);
@@ -85,10 +86,11 @@
* The derived class implements an internal mocked map. It need to implement all functions
* which are related with the native BPF map because the BPF map handler is not initialized.
* See BpfCoordinatorTest#TestBpfMap.
+ * TODO: remove once TestBpfMap derive from IBpfMap.
*/
@VisibleForTesting
protected BpfMap(final Class<K> key, final Class<V> value) {
- mMapFd = -1;
+ mMapFd = ParcelFileDescriptor.adoptFd(-1 /*invalid*/); // unused
mKeyClass = key;
mValueClass = value;
mKeySize = Struct.getSize(key);
@@ -101,7 +103,7 @@
*/
@Override
public void updateEntry(K key, V value) throws ErrnoException {
- writeToMapEntry(mMapFd, key.writeToBytes(), value.writeToBytes(), BPF_ANY);
+ writeToMapEntry(mMapFd.getFd(), key.writeToBytes(), value.writeToBytes(), BPF_ANY);
}
/**
@@ -112,7 +114,7 @@
public void insertEntry(K key, V value)
throws ErrnoException, IllegalStateException {
try {
- writeToMapEntry(mMapFd, key.writeToBytes(), value.writeToBytes(), BPF_NOEXIST);
+ writeToMapEntry(mMapFd.getFd(), key.writeToBytes(), value.writeToBytes(), BPF_NOEXIST);
} catch (ErrnoException e) {
if (e.errno == EEXIST) throw new IllegalStateException(key + " already exists");
@@ -128,7 +130,7 @@
public void replaceEntry(K key, V value)
throws ErrnoException, NoSuchElementException {
try {
- writeToMapEntry(mMapFd, key.writeToBytes(), value.writeToBytes(), BPF_EXIST);
+ writeToMapEntry(mMapFd.getFd(), key.writeToBytes(), value.writeToBytes(), BPF_EXIST);
} catch (ErrnoException e) {
if (e.errno == ENOENT) throw new NoSuchElementException(key + " not found");
@@ -146,13 +148,13 @@
public boolean insertOrReplaceEntry(K key, V value)
throws ErrnoException {
try {
- writeToMapEntry(mMapFd, key.writeToBytes(), value.writeToBytes(), BPF_NOEXIST);
+ writeToMapEntry(mMapFd.getFd(), key.writeToBytes(), value.writeToBytes(), BPF_NOEXIST);
return true; /* insert succeeded */
} catch (ErrnoException e) {
if (e.errno != EEXIST) throw e;
}
try {
- writeToMapEntry(mMapFd, key.writeToBytes(), value.writeToBytes(), BPF_EXIST);
+ writeToMapEntry(mMapFd.getFd(), key.writeToBytes(), value.writeToBytes(), BPF_EXIST);
return false; /* replace succeeded */
} catch (ErrnoException e) {
if (e.errno != ENOENT) throw e;
@@ -169,7 +171,7 @@
/** Remove existing key from eBpf map. Return false if map was not modified. */
@Override
public boolean deleteEntry(K key) throws ErrnoException {
- return deleteMapEntry(mMapFd, key.writeToBytes());
+ return deleteMapEntry(mMapFd.getFd(), key.writeToBytes());
}
/** Returns {@code true} if this map contains no elements. */
@@ -202,7 +204,7 @@
private byte[] getNextRawKey(@Nullable final byte[] key) throws ErrnoException {
byte[] nextKey = new byte[mKeySize];
- if (getNextMapKey(mMapFd, key, nextKey)) return nextKey;
+ if (getNextMapKey(mMapFd.getFd(), key, nextKey)) return nextKey;
return null;
}
@@ -237,7 +239,7 @@
private byte[] getRawValue(final byte[] key) throws ErrnoException {
byte[] value = new byte[mValueSize];
- if (findMapEntry(mMapFd, key, value)) return value;
+ if (findMapEntry(mMapFd.getFd(), key, value)) return value;
return null;
}
@@ -262,8 +264,8 @@
}
@Override
- public void close() throws ErrnoException {
- closeMap(mMapFd);
+ public void close() throws IOException {
+ mMapFd.close();
}
/**
@@ -281,8 +283,6 @@
}
}
- private static native int closeMap(int fd) throws ErrnoException;
-
private native int bpfFdGet(String path, int mode) throws ErrnoException, NullPointerException;
private native void writeToMapEntry(int fd, byte[] key, byte[] value, int flags)
diff --git a/staticlibs/native/bpfmapjni/com_android_net_module_util_BpfMap.cpp b/staticlibs/native/bpfmapjni/com_android_net_module_util_BpfMap.cpp
index e25e17d..e3f48e5 100644
--- a/staticlibs/native/bpfmapjni/com_android_net_module_util_BpfMap.cpp
+++ b/staticlibs/native/bpfmapjni/com_android_net_module_util_BpfMap.cpp
@@ -27,15 +27,6 @@
namespace android {
-static jint com_android_net_module_util_BpfMap_closeMap(JNIEnv *env, jobject clazz,
- jint fd) {
- int ret = close(fd);
-
- if (ret) jniThrowErrnoException(env, "closeMap", errno);
-
- return ret;
-}
-
static jint com_android_net_module_util_BpfMap_bpfFdGet(JNIEnv *env, jobject clazz,
jstring path, jint mode) {
ScopedUtfChars pathname(env, path);
@@ -112,8 +103,6 @@
*/
static const JNINativeMethod gMethods[] = {
/* name, signature, funcPtr */
- { "closeMap", "(I)I",
- (void*) com_android_net_module_util_BpfMap_closeMap },
{ "bpfFdGet", "(Ljava/lang/String;I)I",
(void*) com_android_net_module_util_BpfMap_bpfFdGet },
{ "writeToMapEntry", "(I[B[BI)V",