Fix IpSecManager CTS tests on 4.4 kernels
Investigation shows that 4.4 kernels take longer for loopback TCP
packets to be ack'd, and results in extra ack packets to be generated in
cases where both the server and client sockets send data packets at the
same time. This was verified via TCPdump, where an extra ack packet was
generated per run of the bidirectional transmissions in checkTcp().
This change verifies that the data + ack packets have been sent and
counted before initiating the reverse transmission. Further, changes
have been made to improve the reliability of this code via counting
expected packets (rather than sleeps).
Bug: 62994731
Test: CTS tests run (and passing) on walleye, marlin and angler
Change-Id: I7c707ec3b11235a5a9cba10275aee40e2eb37169
diff --git a/tests/cts/net/src/android/net/cts/IpSecManagerTest.java b/tests/cts/net/src/android/net/cts/IpSecManagerTest.java
index 95a89f6..d435d2b 100644
--- a/tests/cts/net/src/android/net/cts/IpSecManagerTest.java
+++ b/tests/cts/net/src/android/net/cts/IpSecManagerTest.java
@@ -218,7 +218,7 @@
mISM.applyTransportModeTransform(accepted, transform);
// Wait for TCP handshake packets to be counted
- Thread.sleep(250);
+ StatsChecker.waitForNumPackets(3); // (SYN, SYN+ACK, ACK)
// Reset StatsChecker, to ignore negotiation overhead.
StatsChecker.initStatsChecker();
@@ -229,11 +229,18 @@
Os.read(accepted, in, 0, in.length);
assertArrayEquals("Client-to-server encrypted data did not match.", TEST_DATA, in);
+ // Allow for newest data + ack packets to be returned before sending next packet
+ // Also add the number of expected packets in each of the previous runs (4 per run)
+ StatsChecker.waitForNumPackets(2 + (4 * i));
in = new byte[TEST_DATA.length];
Os.write(accepted, TEST_DATA, 0, TEST_DATA.length);
Os.read(client, in, 0, in.length);
assertArrayEquals("Server-to-client encrypted data did not match.", TEST_DATA, in);
+
+ // Allow for all data + ack packets to be returned before sending next packet
+ // Also add the number of expected packets in each of the previous runs (4 per run)
+ StatsChecker.waitForNumPackets(4 * (i + 1));
}
mISM.removeTransportModeTransform(server, transform);
@@ -312,6 +319,7 @@
private static final String LOOPBACK_INTERFACE = "lo";
private static final double ERROR_MARGIN_BYTES = 1.05;
private static final double ERROR_MARGIN_PKTS = 1.05;
+ private static final int MAX_WAIT_TIME_MILLIS = 1000;
private static long uidTxBytes;
private static long uidRxBytes;
@@ -323,6 +331,34 @@
private static long ifaceTxPackets;
private static long ifaceRxPackets;
+ /**
+ * This method counts the number of incoming packets, polling intermittently up to
+ * MAX_WAIT_TIME_MILLIS.
+ */
+ private static void waitForNumPackets(int numPackets) throws Exception {
+ long uidTxDelta = 0;
+ long uidRxDelta = 0;
+ for (int i = 0; i < 100; i++) {
+ uidTxDelta = TrafficStats.getUidTxPackets(Os.getuid()) - uidTxPackets;
+ uidRxDelta = TrafficStats.getUidRxPackets(Os.getuid()) - uidRxPackets;
+
+ // TODO: Check Rx packets as well once kernel security policy bug is fixed.
+ // (b/70635417)
+ if (uidTxDelta >= numPackets) {
+ return;
+ }
+ Thread.sleep(MAX_WAIT_TIME_MILLIS / 100);
+ }
+ fail(
+ "Not enough traffic was recorded to satisfy the provided conditions: wanted "
+ + numPackets
+ + ", got "
+ + uidTxDelta
+ + " tx and "
+ + uidRxDelta
+ + " rx packets");
+ }
+
private static void assertUidStatsDelta(
int expectedTxByteDelta,
int expectedTxPacketDelta,
@@ -449,9 +485,6 @@
}
}
- // Wait for stats to be counted
- Thread.sleep(250);
-
checkStatsChecker(
protocol,
ipHdrLen,
@@ -499,6 +532,8 @@
expectedPackets += sendCount;
}
+ StatsChecker.waitForNumPackets(expectedPackets);
+
if (udpEncapLen != 0) {
StatsChecker.assertUidStatsDelta(
expectedOuterBytes, expectedPackets, expectedOuterBytes, expectedPackets);