Add basic netlink library code.

Add netlink socket helpers and parsing code for basic netlink messages.
Additionally, support from some neighbor discovery -specific messages
is included.

Bug: 18581716
Change-Id: Ib2aa924222b63cdbebf09a8bf8ff35ee24269fc5

2 files changed, 304 insertions, 0 deletions

diff --git a/core/tests/coretests/src/android/net/netlink/NetlinkSocketTest.java b/core/tests/coretests/src/android/net/netlink/NetlinkSocketTest.java
new file mode 100644
index 0000000..b32de78
--- /dev/null
+++ b/core/tests/coretests/src/android/net/netlink/NetlinkSocketTest.java
@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.netlink;
+
+import android.net.netlink.NetlinkSocket;
+import android.net.netlink.RtNetlinkNeighborMessage;
+import android.net.netlink.StructNdMsg;
+import android.net.netlink.StructNlMsgHdr;
+import android.system.ErrnoException;
+import android.system.NetlinkSocketAddress;
+import android.system.OsConstants;
+import android.util.Log;
+import java.io.InterruptedIOException;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import junit.framework.TestCase;
+
+
+public class NetlinkSocketTest extends TestCase {
+    private final String TAG = "NetlinkSocketTest";
+
+    public void testBasicWorkingGetNeighborsQuery() throws Exception {
+        NetlinkSocket s = new NetlinkSocket(OsConstants.NETLINK_ROUTE);
+        assertNotNull(s);
+
+        s.connectToKernel();
+
+        NetlinkSocketAddress localAddr = s.getLocalAddress();
+        assertNotNull(localAddr);
+        assertEquals(0, localAddr.getGroupsMask());
+        assertTrue(0 != localAddr.getPortId());
+
+        final int TEST_SEQNO = 5;
+        final byte[] request = RtNetlinkNeighborMessage.newGetNeighborsRequest(TEST_SEQNO);
+        assertNotNull(request);
+
+        final long TIMEOUT = 500;
+        assertTrue(s.sendMessage(request, 0, request.length, TIMEOUT));
+
+        int neighMessageCount = 0;
+        int doneMessageCount = 0;
+
+        while (doneMessageCount == 0) {
+            ByteBuffer response = null;
+            response = s.recvMessage(TIMEOUT);
+            assertNotNull(response);
+            assertTrue(StructNlMsgHdr.STRUCT_SIZE <= response.limit());
+            assertEquals(0, response.position());
+            assertEquals(ByteOrder.nativeOrder(), response.order());
+
+            // Verify the messages at least appears minimally reasonable.
+            while (response.remaining() > 0) {
+                final NetlinkMessage msg = NetlinkMessage.parse(response);
+                assertNotNull(msg);
+                final StructNlMsgHdr hdr = msg.getHeader();
+                assertNotNull(hdr);
+
+                if (hdr.nlmsg_type == NetlinkConstants.NLMSG_DONE) {
+                    doneMessageCount++;
+                    continue;
+                }
+
+                assertEquals(NetlinkConstants.RTM_NEWNEIGH, hdr.nlmsg_type);
+                assertTrue(msg instanceof RtNetlinkNeighborMessage);
+                assertTrue((hdr.nlmsg_flags & StructNlMsgHdr.NLM_F_MULTI) != 0);
+                assertEquals(TEST_SEQNO, hdr.nlmsg_seq);
+                assertEquals(localAddr.getPortId(), hdr.nlmsg_pid);
+
+                neighMessageCount++;
+            }
+        }
+
+        assertEquals(1, doneMessageCount);
+        // TODO: make sure this test passes sanely in airplane mode.
+        assertTrue(neighMessageCount > 0);
+
+        s.close();
+    }
+}
diff --git a/core/tests/coretests/src/android/net/netlink/RtNetlinkNeighborMessageTest.java b/core/tests/coretests/src/android/net/netlink/RtNetlinkNeighborMessageTest.java
new file mode 100644
index 0000000..0634281
--- /dev/null
+++ b/core/tests/coretests/src/android/net/netlink/RtNetlinkNeighborMessageTest.java
@@ -0,0 +1,211 @@
+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package android.net.netlink;
+
+import android.net.netlink.NetlinkConstants;
+import android.net.netlink.NetlinkMessage;
+import android.net.netlink.RtNetlinkNeighborMessage;
+import android.net.netlink.StructNdMsg;
+import android.net.netlink.StructNlMsgHdr;
+import android.system.OsConstants;
+import android.util.Log;
+import libcore.util.HexEncoding;
+
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
+import junit.framework.TestCase;
+
+
+public class RtNetlinkNeighborMessageTest extends TestCase {
+    private final String TAG = "RtNetlinkNeighborMessageTest";
+
+    // Hexadecimal representation of packet capture.
+    public static final String RTM_DELNEIGH_HEX =
+            // struct nlmsghdr
+            "4c000000" +     // length = 76
+            "1d00" +         // type = 29 (RTM_DELNEIGH)
+            "0000" +         // flags
+            "00000000" +     // seqno
+            "00000000" +     // pid (0 == kernel)
+            // struct ndmsg
+            "02" +           // family
+            "00" +           // pad1
+            "0000" +         // pad2
+            "15000000" +     // interface index (21  == wlan0, on test device)
+            "0400" +         // NUD state (0x04 == NUD_STALE)
+            "00" +           // flags
+            "01" +           // type
+            // struct nlattr: NDA_DST
+            "0800" +         // length = 8
+            "0100" +         // type (1 == NDA_DST, for neighbor messages)
+            "c0a89ffe" +     // IPv4 address (== 192.168.159.254)
+            // struct nlattr: NDA_LLADDR
+            "0a00" +         // length = 10
+            "0200" +         // type (2 == NDA_LLADDR, for neighbor messages)
+            "00005e000164" + // MAC Address (== 00:00:5e:00:01:64)
+            "0000" +         // padding, for 4 byte alignment
+            // struct nlattr: NDA_PROBES
+            "0800" +         // length = 8
+            "0400" +         // type (4 == NDA_PROBES, for neighbor messages)
+            "01000000" +     // number of probes
+            // struct nlattr: NDA_CACHEINFO
+            "1400" +         // length = 20
+            "0300" +         // type (3 == NDA_CACHEINFO, for neighbor messages)
+            "05190000" +     // ndm_used, as "clock ticks ago"
+            "05190000" +     // ndm_confirmed, as "clock ticks ago"
+            "190d0000" +     // ndm_updated, as "clock ticks ago"
+            "00000000";      // ndm_refcnt
+    public static final byte[] RTM_DELNEIGH =
+            HexEncoding.decode(RTM_DELNEIGH_HEX.toCharArray(), false);
+
+    // Hexadecimal representation of packet capture.
+    public static final String RTM_NEWNEIGH_HEX =
+            // struct nlmsghdr
+            "58000000" +     // length = 88
+            "1c00" +         // type = 28 (RTM_NEWNEIGH)
+            "0000" +         // flags
+            "00000000" +     // seqno
+            "00000000" +     // pid (0 == kernel)
+            // struct ndmsg
+            "0a" +           // family
+            "00" +           // pad1
+            "0000" +         // pad2
+            "15000000" +     // interface index (21  == wlan0, on test device)
+            "0400" +         // NUD state (0x04 == NUD_STALE)
+            "80" +           // flags
+            "01" +           // type
+            // struct nlattr: NDA_DST
+            "1400" +         // length = 20
+            "0100" +         // type (1 == NDA_DST, for neighbor messages)
+            "fe8000000000000086c9b2fffe6aed4b" + // IPv6 address (== fe80::86c9:b2ff:fe6a:ed4b)
+            // struct nlattr: NDA_LLADDR
+            "0a00" +         // length = 10
+            "0200" +         // type (2 == NDA_LLADDR, for neighbor messages)
+            "84c9b26aed4b" + // MAC Address (== 84:c9:b2:6a:ed:4b)
+            "0000" +         // padding, for 4 byte alignment
+            // struct nlattr: NDA_PROBES
+            "0800" +         // length = 8
+            "0400" +         // type (4 == NDA_PROBES, for neighbor messages)
+            "01000000" +     // number of probes
+            // struct nlattr: NDA_CACHEINFO
+            "1400" +         // length = 20
+            "0300" +         // type (3 == NDA_CACHEINFO, for neighbor messages)
+            "eb0e0000" +     // ndm_used, as "clock ticks ago"
+            "861f0000" +     // ndm_confirmed, as "clock ticks ago"
+            "00000000" +     // ndm_updated, as "clock ticks ago"
+            "05000000";      // ndm_refcnt
+    public static final byte[] RTM_NEWNEIGH =
+            HexEncoding.decode(RTM_NEWNEIGH_HEX.toCharArray(), false);
+
+    // An example of the full response from an RTM_GETNEIGH query.
+    private static final String RTM_GETNEIGH_RESPONSE_HEX =
+            // <-- struct nlmsghr             -->|<-- struct ndmsg           -->|<-- struct nlattr: NDA_DST             -->|<-- NDA_LLADDR          -->|<-- NDA_PROBES -->|<-- NDA_CACHEINFO                         -->|
+            "58000000 1c00 0200 00000000 3e2b0000 0a 00 0000 15000000 4000 00 05 1400 0100 ff020000000000000000000000000001 0a00 0200 333300000001 0000 0800 0400 00000000 1400 0300 a2280000 32110000 32110000 01000000" +
+            "58000000 1c00 0200 00000000 3e2b0000 0a 00 0000 15000000 4000 00 05 1400 0100 ff0200000000000000000001ff000001 0a00 0200 3333ff000001 0000 0800 0400 00000000 1400 0300 0d280000 9d100000 9d100000 00000000" +
+            "58000000 1c00 0200 00000000 3e2b0000 0a 00 0000 15000000 0400 80 01 1400 0100 20010db800040ca00000000000000001 0a00 0200 84c9b26aed4b 0000 0800 0400 04000000 1400 0300 90100000 90100000 90080000 01000000" +
+            "58000000 1c00 0200 00000000 3e2b0000 0a 00 0000 15000000 4000 00 05 1400 0100 ff0200000000000000000001ff47da19 0a00 0200 3333ff47da19 0000 0800 0400 00000000 1400 0300 a1280000 31110000 31110000 01000000" +
+            "58000000 1c00 0200 00000000 3e2b0000 0a 00 0000 14000000 4000 00 05 1400 0100 ff020000000000000000000000000016 0a00 0200 333300000016 0000 0800 0400 00000000 1400 0300 912a0000 21130000 21130000 00000000" +
+            "58000000 1c00 0200 00000000 3e2b0000 0a 00 0000 14000000 4000 00 05 1400 0100 ff0200000000000000000001ffeace3b 0a00 0200 3333ffeace3b 0000 0800 0400 00000000 1400 0300 922a0000 22130000 22130000 00000000" +
+            "58000000 1c00 0200 00000000 3e2b0000 0a 00 0000 15000000 4000 00 05 1400 0100 ff0200000000000000000001ff5c2a83 0a00 0200 3333ff5c2a83 0000 0800 0400 00000000 1400 0300 391c0000 c9040000 c9040000 01000000" +
+            "58000000 1c00 0200 00000000 3e2b0000 0a 00 0000 01000000 4000 00 02 1400 0100 00000000000000000000000000000000 0a00 0200 000000000000 0000 0800 0400 00000000 1400 0300 cd180200 5d010200 5d010200 08000000" +
+            "58000000 1c00 0200 00000000 3e2b0000 0a 00 0000 15000000 4000 00 05 1400 0100 ff020000000000000000000000000002 0a00 0200 333300000002 0000 0800 0400 00000000 1400 0300 352a0000 c5120000 c5120000 00000000" +
+            "58000000 1c00 0200 00000000 3e2b0000 0a 00 0000 15000000 4000 00 05 1400 0100 ff020000000000000000000000000016 0a00 0200 333300000016 0000 0800 0400 00000000 1400 0300 982a0000 28130000 28130000 00000000" +
+            "58000000 1c00 0200 00000000 3e2b0000 0a 00 0000 15000000 0800 80 01 1400 0100 fe8000000000000086c9b2fffe6aed4b 0a00 0200 84c9b26aed4b 0000 0800 0400 00000000 1400 0300 23000000 24000000 57000000 13000000" +
+            "58000000 1c00 0200 00000000 3e2b0000 0a 00 0000 15000000 4000 00 05 1400 0100 ff0200000000000000000001ffeace3b 0a00 0200 3333ffeace3b 0000 0800 0400 00000000 1400 0300 992a0000 29130000 29130000 01000000" +
+            "58000000 1c00 0200 00000000 3e2b0000 0a 00 0000 14000000 4000 00 05 1400 0100 ff020000000000000000000000000002 0a00 0200 333300000002 0000 0800 0400 00000000 1400 0300 2e2a0000 be120000 be120000 00000000" +
+            "44000000 1c00 0200 00000000 3e2b0000 02 00 0000 18000000 4000 00 03 0800 0100 00000000                         0400 0200                   0800 0400 00000000 1400 0300 75280000 05110000 05110000 22000000";
+    public static final byte[] RTM_GETNEIGH_RESPONSE =
+            HexEncoding.decode(RTM_GETNEIGH_RESPONSE_HEX.replaceAll(" ", "").toCharArray(), false);
+
+    public void testParseRtNetlinkNeighborRtmDelNeigh() {
+        final ByteBuffer byteBuffer = ByteBuffer.wrap(RTM_DELNEIGH);
+        byteBuffer.order(ByteOrder.LITTLE_ENDIAN);  // For testing.
+        final NetlinkMessage msg = NetlinkMessage.parse(byteBuffer);
+        assertNotNull(msg);
+        assertTrue(msg instanceof RtNetlinkNeighborMessage);
+        final RtNetlinkNeighborMessage neighMsg = (RtNetlinkNeighborMessage) msg;
+
+        final StructNlMsgHdr hdr = neighMsg.getHeader();
+        assertNotNull(hdr);
+        assertEquals(76, hdr.nlmsg_len);
+        assertEquals(NetlinkConstants.RTM_DELNEIGH, hdr.nlmsg_type);
+        assertEquals(0, hdr.nlmsg_flags);
+        assertEquals(0, hdr.nlmsg_seq);
+        assertEquals(0, hdr.nlmsg_pid);
+
+        final StructNdMsg ndmsgHdr = neighMsg.getNdHeader();
+        assertNotNull(ndmsgHdr);
+        assertEquals((byte) OsConstants.AF_INET, ndmsgHdr.ndm_family);
+        assertEquals(21, ndmsgHdr.ndm_ifindex);
+        assertEquals(StructNdMsg.NUD_STALE, ndmsgHdr.ndm_state);
+        final InetAddress destination = neighMsg.getDestination();
+        assertNotNull(destination);
+        assertEquals(InetAddress.parseNumericAddress("192.168.159.254"), destination);
+    }
+
+    public void testParseRtNetlinkNeighborRtmNewNeigh() {
+        final ByteBuffer byteBuffer = ByteBuffer.wrap(RTM_NEWNEIGH);
+        byteBuffer.order(ByteOrder.LITTLE_ENDIAN);  // For testing.
+        final NetlinkMessage msg = NetlinkMessage.parse(byteBuffer);
+        assertNotNull(msg);
+        assertTrue(msg instanceof RtNetlinkNeighborMessage);
+        final RtNetlinkNeighborMessage neighMsg = (RtNetlinkNeighborMessage) msg;
+
+        final StructNlMsgHdr hdr = neighMsg.getHeader();
+        assertNotNull(hdr);
+        assertEquals(88, hdr.nlmsg_len);
+        assertEquals(NetlinkConstants.RTM_NEWNEIGH, hdr.nlmsg_type);
+        assertEquals(0, hdr.nlmsg_flags);
+        assertEquals(0, hdr.nlmsg_seq);
+        assertEquals(0, hdr.nlmsg_pid);
+
+        final StructNdMsg ndmsgHdr = neighMsg.getNdHeader();
+        assertNotNull(ndmsgHdr);
+        assertEquals((byte) OsConstants.AF_INET6, ndmsgHdr.ndm_family);
+        assertEquals(21, ndmsgHdr.ndm_ifindex);
+        assertEquals(StructNdMsg.NUD_STALE, ndmsgHdr.ndm_state);
+        final InetAddress destination = neighMsg.getDestination();
+        assertNotNull(destination);
+        assertEquals(InetAddress.parseNumericAddress("fe80::86c9:b2ff:fe6a:ed4b"), destination);
+    }
+
+    public void testParseRtNetlinkNeighborRtmGetNeighResponse() {
+        final ByteBuffer byteBuffer = ByteBuffer.wrap(RTM_GETNEIGH_RESPONSE);
+        byteBuffer.order(ByteOrder.LITTLE_ENDIAN);  // For testing.
+
+        int messageCount = 0;
+        while (byteBuffer.remaining() > 0) {
+            final NetlinkMessage msg = NetlinkMessage.parse(byteBuffer);
+            assertNotNull(msg);
+            assertTrue(msg instanceof RtNetlinkNeighborMessage);
+            final RtNetlinkNeighborMessage neighMsg = (RtNetlinkNeighborMessage) msg;
+
+            final StructNlMsgHdr hdr = neighMsg.getHeader();
+            assertNotNull(hdr);
+            assertEquals(NetlinkConstants.RTM_NEWNEIGH, hdr.nlmsg_type);
+            assertEquals(StructNlMsgHdr.NLM_F_MULTI, hdr.nlmsg_flags);
+            assertEquals(0, hdr.nlmsg_seq);
+            assertEquals(11070, hdr.nlmsg_pid);
+
+            messageCount++;
+        }
+        // TODO: add more detailed spot checks.
+        assertEquals(14, messageCount);
+    }
+}