From bd85f8903eb114cf3c267377947c64a24bf0a390 Mon Sep 17 00:00:00 2001
From: Hungming Chen <nuccachen@google.com>
Date: Mon, 14 Mar 2022 16:11:06 +0800
Subject: [PATCH] ClatCoordinator: use Java class BpfMap to remove clat rule

This a preparation to replace duplicated native functions with the
existing Java class.

Bug: 221213090
Test: atest FrameworksNetTests
Test: manual check

Steps:
1. Connect wlan and check map content {iface index, v4addr, v6addr, pfx96} manually
after clat started.
$ adb shell dumpsys netd
  ClatdController
    BPF ingress map: iif(iface) nat64Prefix v6Addr -> v4Addr oif(iface)
      47(wlan0) 64:ff9b::/96 2a00:79e1:abc:6f02:2479:2f51:25a9:28f1 -> 192.0.0.4 53(v4-wlan0)
    BPF egress map: iif(iface) v4Addr -> v6Addr nat64Prefix oif(iface)
      53(v4-wlan0) 192.0.0.4 -> 2a00:79e1:abc:6f02:2479:2f51:25a9:28f1 64:ff9b::/96 47(wlan0) ether

2. Disconnect wlan and check the bpf map is removed.
$ adb shell dumpsys netd
  ClatdController
    BPF ingress map: iif(iface) nat64Prefix v6Addr -> v4Addr oif(iface)
    BPF egress map: iif(iface) v4Addr -> v6Addr nat64Prefix oif(iface)

Change-Id: Ia0c90c7104c4a42d34a28a5ddf3cf13a289f8c76
---
 service/native/libs/libclat/bpfhelper.cpp     | 20 -----------------
 .../server/connectivity/ClatCoordinator.java  | 22 +++++++++++++++++++
 .../connectivity/ClatCoordinatorTest.java     |  2 ++
 3 files changed, 24 insertions(+), 20 deletions(-)

diff --git a/service/native/libs/libclat/bpfhelper.cpp b/service/native/libs/libclat/bpfhelper.cpp
index c05a05868a..475675fa56 100644
--- a/service/native/libs/libclat/bpfhelper.cpp
+++ b/service/native/libs/libclat/bpfhelper.cpp
@@ -139,26 +139,6 @@ void maybeStopBpf(const ClatdTracker& tracker) {
         ALOGE("tcFilterDelDevEgressClatIpv4(%d[%s]) failure: %s", tracker.v4ifIndex,
               tracker.v4iface, strerror(-rv));
     }
-
-    // We cleanup the maps last, so scanning through them can be used to
-    // determine what still needs cleanup.
-
-    ClatEgress4Key txKey = {
-            .iif = tracker.v4ifIndex,
-            .local4 = tracker.v4,
-    };
-
-    auto ret = mClatEgress4Map.deleteValue(txKey);
-    if (!ret.ok()) ALOGE("mClatEgress4Map.deleteValue failure: %s", strerror(ret.error().code()));
-
-    ClatIngress6Key rxKey = {
-            .iif = tracker.ifIndex,
-            .pfx96 = tracker.pfx96,
-            .local6 = tracker.v6,
-    };
-
-    ret = mClatIngress6Map.deleteValue(rxKey);
-    if (!ret.ok()) ALOGE("mClatIngress6Map.deleteValue failure: %s", strerror(ret.error().code()));
 }
 
 }  // namespace clat
diff --git a/service/src/com/android/server/connectivity/ClatCoordinator.java b/service/src/com/android/server/connectivity/ClatCoordinator.java
index 253e56c791..35b8f17c82 100644
--- a/service/src/com/android/server/connectivity/ClatCoordinator.java
+++ b/service/src/com/android/server/connectivity/ClatCoordinator.java
@@ -563,6 +563,27 @@ public class ClatCoordinator {
         return v6Str;
     }
 
+    private void maybeStopBpf(final ClatdTracker tracker) {
+        if (mIngressMap == null || mEgressMap == null) return;
+
+        final ClatEgress4Key txKey = new ClatEgress4Key(tracker.v4ifIndex, tracker.v4);
+        try {
+            mEgressMap.deleteEntry(txKey);
+        } catch (ErrnoException | IllegalStateException e) {
+            Log.e(TAG, "Could not delete entry (" + txKey + "): " + e);
+        }
+
+        final ClatIngress6Key rxKey = new ClatIngress6Key(tracker.ifIndex, tracker.pfx96,
+                tracker.v6);
+        try {
+            mIngressMap.deleteEntry(rxKey);
+        } catch (ErrnoException | IllegalStateException e) {
+            Log.e(TAG, "Could not delete entry (" + rxKey + "): " + e);
+        }
+
+        // TODO: dettach program.
+    }
+
     /**
      * Stop clatd
      */
@@ -572,6 +593,7 @@ public class ClatCoordinator {
         }
         Log.i(TAG, "Stopping clatd pid=" + mClatdTracker.pid + " on " + mClatdTracker.iface);
 
+        maybeStopBpf(mClatdTracker);
         mDeps.stopClatd(mClatdTracker.iface, mClatdTracker.pfx96.getHostAddress(),
                 mClatdTracker.v4.getHostAddress(), mClatdTracker.v6.getHostAddress(),
                 mClatdTracker.pid);
diff --git a/tests/unit/java/com/android/server/connectivity/ClatCoordinatorTest.java b/tests/unit/java/com/android/server/connectivity/ClatCoordinatorTest.java
index dc81038c67..790473d5f7 100644
--- a/tests/unit/java/com/android/server/connectivity/ClatCoordinatorTest.java
+++ b/tests/unit/java/com/android/server/connectivity/ClatCoordinatorTest.java
@@ -426,6 +426,8 @@ public class ClatCoordinatorTest {
 
         // [3] Expect clatd to stop successfully.
         coordinator.clatStop();
+        inOrder.verify(mEgressMap).deleteEntry(eq(EGRESS_KEY));
+        inOrder.verify(mIngressMap).deleteEntry(eq(INGRESS_KEY));
         inOrder.verify(mDeps).stopClatd(eq(BASE_IFACE), eq(NAT64_PREFIX_STRING),
                 eq(XLAT_LOCAL_IPV4ADDR_STRING), eq(XLAT_LOCAL_IPV6ADDR_STRING), eq(CLATD_PID));
         inOrder.verify(mDeps).untagSocket(eq(RAW_SOCK_COOKIE));