2 files changed, 154 insertions, 2 deletions
diff --git a/services/net/java/android/net/dhcp/DhcpClient.java b/services/net/java/android/net/dhcp/DhcpClient.java
index 9ee9cf4..e0d2ac1 100644
--- a/services/net/java/android/net/dhcp/DhcpClient.java
+++ b/services/net/java/android/net/dhcp/DhcpClient.java
@@ -244,8 +244,9 @@ public class DhcpClient extends BaseDhcpStateMachine {
     private PendingIntent createStateMachineCommandIntent(final String cmdName, final int cmd) {
         String action = DhcpClient.class.getName() + "." + mIfaceName + "." + cmdName;
 
-        Intent intent = new Intent(action, null)
-                .addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT);
+        Intent intent = new Intent(action, null).addFlags(
+                Intent.FLAG_RECEIVER_REGISTERED_ONLY_BEFORE_BOOT |
+                Intent.FLAG_RECEIVER_FOREGROUND);
         // TODO: The intent's package covers the whole of the system server, so it's pretty generic.
         // Consider adding some sort of token as well.
         intent.setPackage(mContext.getPackageName());
diff --git a/services/net/java/android/net/util/IpUtils.java b/services/net/java/android/net/util/IpUtils.java
new file mode 100644
index 0000000..e037c40
--- /dev/null
+++ b/services/net/java/android/net/util/IpUtils.java
@@ -0,0 +1,151 @@
+/*
+ * 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.util;
+
+import java.net.Inet6Address;
+import java.net.InetAddress;
+import java.nio.BufferOverflowException;
+import java.nio.BufferUnderflowException;
+import java.nio.ByteBuffer;
+import java.nio.ShortBuffer;
+
+import static android.system.OsConstants.IPPROTO_TCP;
+import static android.system.OsConstants.IPPROTO_UDP;
+
+/**
+ * @hide
+ */
+public class IpUtils {
+    /**
+     * Converts a signed short value to an unsigned int value.  Needed
+     * because Java does not have unsigned types.
+     */
+    private static int intAbs(short v) {
+        return v & 0xFFFF;
+    }
+
+    /**
+     * Performs an IP checksum (used in IP header and across UDP
+     * payload) on the specified portion of a ByteBuffer.  The seed
+     * allows the checksum to commence with a specified value.
+     */
+    private static int checksum(ByteBuffer buf, int seed, int start, int end) {
+        int sum = seed;
+        final int bufPosition = buf.position();
+
+        // set position of original ByteBuffer, so that the ShortBuffer
+        // will be correctly initialized
+        buf.position(start);
+        ShortBuffer shortBuf = buf.asShortBuffer();
+
+        // re-set ByteBuffer position
+        buf.position(bufPosition);
+
+        final int numShorts = (end - start) / 2;
+        for (int i = 0; i < numShorts; i++) {
+            sum += intAbs(shortBuf.get(i));
+        }
+        start += numShorts * 2;
+
+        // see if a singleton byte remains
+        if (end != start) {
+            short b = buf.get(start);
+
+            // make it unsigned
+            if (b < 0) {
+                b += 256;
+            }
+
+            sum += b * 256;
+        }
+
+        sum = ((sum >> 16) & 0xFFFF) + (sum & 0xFFFF);
+        sum = ((sum + ((sum >> 16) & 0xFFFF)) & 0xFFFF);
+        int negated = ~sum;
+        return intAbs((short) negated);
+    }
+
+    private static int pseudoChecksumIPv4(
+            ByteBuffer buf, int headerOffset, int protocol, int transportLen) {
+        int partial = protocol + transportLen;
+        partial += intAbs(buf.getShort(headerOffset + 12));
+        partial += intAbs(buf.getShort(headerOffset + 14));
+        partial += intAbs(buf.getShort(headerOffset + 16));
+        partial += intAbs(buf.getShort(headerOffset + 18));
+        return partial;
+    }
+
+    private static int pseudoChecksumIPv6(
+            ByteBuffer buf, int headerOffset, int protocol, int transportLen) {
+        int partial = protocol + transportLen;
+        for (int offset = 8; offset < 40; offset += 2) {
+            partial += intAbs(buf.getShort(headerOffset + offset));
+        }
+        return partial;
+    }
+
+    private static byte ipversion(ByteBuffer buf, int headerOffset) {
+        return (byte) ((buf.get(headerOffset) & (byte) 0xf0) >> 4);
+   }
+
+    public static short ipChecksum(ByteBuffer buf, int headerOffset) {
+        byte ihl = (byte) (buf.get(headerOffset) & 0x0f);
+        return (short) checksum(buf, 0, headerOffset, headerOffset + ihl * 4);
+    }
+
+    private static short transportChecksum(ByteBuffer buf, int protocol,
+            int ipOffset, int transportOffset, int transportLen) {
+        if (transportLen < 0) {
+            throw new IllegalArgumentException("Transport length < 0: " + transportLen);
+        }
+        int sum;
+        byte ver = ipversion(buf, ipOffset);
+        if (ver == 4) {
+            sum = pseudoChecksumIPv4(buf, ipOffset, protocol, transportLen);
+        } else if (ver == 6) {
+            sum = pseudoChecksumIPv6(buf, ipOffset, protocol, transportLen);
+        } else {
+            throw new UnsupportedOperationException("Checksum must be IPv4 or IPv6");
+        }
+
+        sum = checksum(buf, sum, transportOffset, transportOffset + transportLen);
+        if (protocol == IPPROTO_UDP && sum == 0) {
+            sum = (short) 0xffff;
+        }
+        return (short) sum;
+    }
+
+    public static short udpChecksum(ByteBuffer buf, int ipOffset, int transportOffset) {
+        int transportLen = intAbs(buf.getShort(transportOffset + 4));
+        return transportChecksum(buf, IPPROTO_UDP, ipOffset, transportOffset, transportLen);
+    }
+
+    public static short tcpChecksum(ByteBuffer buf, int ipOffset, int transportOffset,
+            int transportLen) {
+        return transportChecksum(buf, IPPROTO_TCP, ipOffset, transportOffset, transportLen);
+    }
+
+    public static String addressAndPortToString(InetAddress address, int port) {
+        return String.format(
+                (address instanceof Inet6Address) ? "[%s]:%d" : "%s:%d",
+                address.getHostAddress(), port);
+    }
+
+    public static boolean isValidUdpOrTcpPort(int port) {
+        return port > 0 && port < 65536;
+    }
+}