Add build ICMPv6 echo request packet helper function in Ipv6Utils.

Bug: 168868607
Test: atest NetworkStaticLibTests
Change-Id: Ibd3c8348996c8b55767956b03978a69593ec29e7

2 files changed, 30 insertions, 0 deletions

diff --git a/common/device/com/android/net/module/util/Ipv6Utils.java b/common/device/com/android/net/module/util/Ipv6Utils.java
index ee43ae99..fe7c89bc 100644
--- a/common/device/com/android/net/module/util/Ipv6Utils.java
+++ b/common/device/com/android/net/module/util/Ipv6Utils.java
@@ -20,6 +20,7 @@ import static android.system.OsConstants.IPPROTO_ICMPV6;
 
 import static com.android.net.module.util.IpUtils.icmpv6Checksum;
 import static com.android.net.module.util.NetworkStackConstants.ETHER_TYPE_IPV6;
+import static com.android.net.module.util.NetworkStackConstants.ICMPV6_ECHO_REQUEST_TYPE;
 import static com.android.net.module.util.NetworkStackConstants.ICMPV6_NEIGHBOR_ADVERTISEMENT;
 import static com.android.net.module.util.NetworkStackConstants.ICMPV6_NEIGHBOR_SOLICITATION;
 import static com.android.net.module.util.NetworkStackConstants.ICMPV6_ROUTER_ADVERTISEMENT;
@@ -148,4 +149,14 @@ public class Ipv6Utils {
         return buildIcmpv6Packet(srcMac, dstMac, srcIp, dstIp,
                 (byte) ICMPV6_ROUTER_SOLICITATION /* type */, (byte) 0 /* code */, payload);
     }
+
+    /**
+     * Build an ICMPv6 Echo Request packet from the required specified parameters.
+     */
+    public static ByteBuffer buildEchoRequestPacket(final MacAddress srcMac,
+            final MacAddress dstMac, final Inet6Address srcIp, final Inet6Address dstIp) {
+        final ByteBuffer payload = ByteBuffer.allocate(4); // ID and Sequence number may be zero.
+        return buildIcmpv6Packet(srcMac, dstMac, srcIp, dstIp,
+                (byte) ICMPV6_ECHO_REQUEST_TYPE /* type */, (byte) 0 /* code */, payload);
+    }
 }
diff --git a/common/tests/unit/src/com/android/net/module/util/Ipv6UtilsTest.java b/common/tests/unit/src/com/android/net/module/util/Ipv6UtilsTest.java
index 37278b3d..03a1ec9f 100644
--- a/common/tests/unit/src/com/android/net/module/util/Ipv6UtilsTest.java
+++ b/common/tests/unit/src/com/android/net/module/util/Ipv6UtilsTest.java
@@ -112,6 +112,25 @@ public class Ipv6UtilsTest {
         assertPioEquals(pio, "fdcd:a17f:6502:1::/64", pioFlags, 86400, 86400);
     }
 
+    @Test
+    public void testBuildEchoRequestPacket() {
+        final ByteBuffer b = Ipv6Utils.buildEchoRequestPacket(MAC2, MAC1, LINK_LOCAL, ALL_NODES);
+
+        EthernetHeader eth = Struct.parse(EthernetHeader.class, b);
+        assertEquals(MAC2, eth.srcMac);
+        assertEquals(MAC1, eth.dstMac);
+
+        Ipv6Header ipv6 = Struct.parse(Ipv6Header.class, b);
+        assertEquals(255, ipv6.hopLimit);
+        assertEquals(OsConstants.IPPROTO_ICMPV6, ipv6.nextHeader);
+        assertEquals(LINK_LOCAL, ipv6.srcIp);
+        assertEquals(ALL_NODES, ipv6.dstIp);
+
+        Icmpv6Header icmpv6 = Struct.parse(Icmpv6Header.class, b);
+        assertEquals(NetworkStackConstants.ICMPV6_ECHO_REQUEST_TYPE, icmpv6.type);
+        assertEquals(0, icmpv6.code);
+    }
+
     private void assertPioEquals(PrefixInformationOption pio, String prefix, byte flags,
             long valid, long preferred) {
         assertEquals(NetworkStackConstants.ICMPV6_ND_OPTION_PIO, pio.type);