LineageOS/android_packages_modules_Connectivity
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Address comments and final cleanup from refcounting integration

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Added some extra comments on reference counting and moved a few methods
around. No significant logical changes made in this CL

Bug: 63409385
Test: CTS, Unit tests (both frameworks-base and netd) and binder tests
all pass

Change-Id: I89f1f4a021db48ae406fefefa6aca7406045736c
This commit is contained in:
Benedict Wong
2017-12-13 17:16:53 -08:00
parent 0d483b76f3
commit cbd329b14a
1 changed files with 63 additions and 27 deletions
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90
services/core/java/com/android/server/IpSecService.java
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@@ -148,7 +148,7 @@ public class IpSecService extends IIpSecService.Stub {
* resources.
*
* <p>References to the IResource object may be held by other RefcountedResource objects,
* and as such, the kernel resources and quota may not be cleaned up.
* and as such, the underlying resources and quota may not be cleaned up.
*/
void invalidate() throws RemoteException;
@@ -298,7 +298,12 @@ public class IpSecService extends IIpSecService.Stub {
}
}
/* Very simple counting class that looks much like a counting semaphore */
/**
* Very simple counting class that looks much like a counting semaphore
*
* <p>This class is not thread-safe, and expects that that users of this class will ensure
* synchronization and thread safety by holding the IpSecService.this instance lock.
*/
@VisibleForTesting
static class ResourceTracker {
private final int mMax;
@@ -341,26 +346,38 @@ public class IpSecService extends IIpSecService.Stub {
@VisibleForTesting
static final class UserRecord {
/* Type names */
public static final String TYPENAME_SPI = "SecurityParameterIndex";
public static final String TYPENAME_TRANSFORM = "IpSecTransform";
public static final String TYPENAME_ENCAP_SOCKET = "UdpEncapSocket";
/* Maximum number of each type of resource that a single UID may possess */
public static final int MAX_NUM_ENCAP_SOCKETS = 2;
public static final int MAX_NUM_TRANSFORMS = 4;
public static final int MAX_NUM_SPIS = 8;
/**
* Store each of the OwnedResource types in an (thinly wrapped) sparse array for indexing
* and explicit (user) reference management.
*
* <p>These are stored in separate arrays to improve debuggability and dump output clarity.
*
* <p>Resources are removed from this array when the user releases their explicit reference
* by calling one of the releaseResource() methods.
*/
final RefcountedResourceArray<SpiRecord> mSpiRecords =
new RefcountedResourceArray<>(TYPENAME_SPI);
final ResourceTracker mSpiQuotaTracker = new ResourceTracker(MAX_NUM_SPIS);
new RefcountedResourceArray<>(SpiRecord.class.getSimpleName());
final RefcountedResourceArray<TransformRecord> mTransformRecords =
new RefcountedResourceArray<>(TYPENAME_TRANSFORM);
final ResourceTracker mTransformQuotaTracker = new ResourceTracker(MAX_NUM_TRANSFORMS);
new RefcountedResourceArray<>(TransformRecord.class.getSimpleName());
final RefcountedResourceArray<EncapSocketRecord> mEncapSocketRecords =
new RefcountedResourceArray<>(TYPENAME_ENCAP_SOCKET);
new RefcountedResourceArray<>(EncapSocketRecord.class.getSimpleName());
/**
* Trackers for quotas for each of the OwnedResource types.
*
* <p>These trackers are separate from the resource arrays, since they are incremented and
* decremented at different points in time. Specifically, quota is only returned upon final
* resource deallocation (after all explicit and implicit references are released). Note
* that it is possible that calls to releaseResource() will not return the used quota if
* there are other resources that depend on (are parents of) the resource being released.
*/
final ResourceTracker mSpiQuotaTracker = new ResourceTracker(MAX_NUM_SPIS);
final ResourceTracker mTransformQuotaTracker = new ResourceTracker(MAX_NUM_TRANSFORMS);
final ResourceTracker mSocketQuotaTracker = new ResourceTracker(MAX_NUM_ENCAP_SOCKETS);
void removeSpiRecord(int resourceId) {
@@ -395,11 +412,15 @@ public class IpSecService extends IIpSecService.Stub {
}
}
/**
* This class is not thread-safe, and expects that that users of this class will ensure
* synchronization and thread safety by holding the IpSecService.this instance lock.
*/
@VisibleForTesting
static final class UserResourceTracker {
private final SparseArray<UserRecord> mUserRecords = new SparseArray<>();
/** Never-fail getter that populates the list of UIDs as-needed */
/** Lazy-initialization/getter that populates or retrieves the UserRecord as needed */
public UserRecord getUserRecord(int uid) {
checkCallerUid(uid);
@@ -428,18 +449,20 @@ public class IpSecService extends IIpSecService.Stub {
@VisibleForTesting final UserResourceTracker mUserResourceTracker = new UserResourceTracker();
/**
* The KernelResourceRecord class provides a facility to cleanly and reliably track system
* The OwnedResourceRecord class provides a facility to cleanly and reliably track system
* resources. It relies on a provided resourceId that should uniquely identify the kernel
* resource. To use this class, the user should implement the invalidate() and
* freeUnderlyingResources() methods that are responsible for cleaning up IpSecService resource
* tracking arrays and kernel resources, respectively
* tracking arrays and kernel resources, respectively.
*
* <p>This class associates kernel resources with the UID that owns and controls them.
*/
private abstract class KernelResourceRecord implements IResource {
private abstract class OwnedResourceRecord implements IResource {
final int pid;
final int uid;
protected final int mResourceId;
KernelResourceRecord(int resourceId) {
OwnedResourceRecord(int resourceId) {
super();
if (resourceId == INVALID_RESOURCE_ID) {
throw new IllegalArgumentException("Resource ID must not be INVALID_RESOURCE_ID");
@@ -479,8 +502,6 @@ public class IpSecService extends IIpSecService.Stub {
}
};
// TODO: Move this to right after RefcountedResource. With this here, Gerrit was showing many
// more things as changed.
/**
* Thin wrapper over SparseArray to ensure resources exist, and simplify generic typing.
*
@@ -534,7 +555,12 @@ public class IpSecService extends IIpSecService.Stub {
}
}
private final class TransformRecord extends KernelResourceRecord {
/**
* Tracks an SA in the kernel, and manages cleanup paths. Once a TransformRecord is
* created, the SpiRecord that originally tracked the SAs will reliquish the
* responsibility of freeing the underlying SA to this class via the mOwnedByTransform flag.
*/
private final class TransformRecord extends OwnedResourceRecord {
private final IpSecConfig mConfig;
private final SpiRecord mSpi;
private final EncapSocketRecord mSocket;
@@ -603,7 +629,12 @@ public class IpSecService extends IIpSecService.Stub {
}
}
private final class SpiRecord extends KernelResourceRecord {
/**
* Tracks a single SA in the kernel, and manages cleanup paths. Once used in a Transform, the
* responsibility for cleaning up underlying resources will be passed to the TransformRecord
* object
*/
private final class SpiRecord extends OwnedResourceRecord {
private final String mSourceAddress;
private final String mDestinationAddress;
private int mSpi;
@@ -692,7 +723,14 @@ public class IpSecService extends IIpSecService.Stub {
}
}
private final class EncapSocketRecord extends KernelResourceRecord {
/**
* Tracks a UDP encap socket, and manages cleanup paths
*
* <p>While this class does not manage non-kernel resources, race conditions around socket
* binding require that the service creates the encap socket, binds it and applies the socket
* policy before handing it to a user.
*/
private final class EncapSocketRecord extends OwnedResourceRecord {
private FileDescriptor mSocket;
private final int mPort;
@@ -1112,9 +1150,7 @@ public class IpSecService extends IIpSecService.Stub {
final int resourceId = mNextResourceId++;
UserRecord userRecord = mUserResourceTracker.getUserRecord(Binder.getCallingUid());
// Avoid resizing by creating a dependency array of min-size 2 (1 UDP encap + 1 SPI)
List<RefcountedResource> dependencies = new ArrayList<>(2);
List<RefcountedResource> dependencies = new ArrayList<>();
if (!userRecord.mTransformQuotaTracker.isAvailable()) {
return new IpSecTransformResponse(IpSecManager.Status.RESOURCE_UNAVAILABLE);