LineageOS/android_packages_modules_Connectivity
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Merge "Add helper method to generate a v6 NAT-T keepalive packet"

Browse Source
This commit is contained in:
Maciej Żenczykowski
2023-06-14 02:55:29 +00:00
committed by Gerrit Code Review
parent 4f68ecf4ed c18f0bbbb3
commit 977fa60f5d
3 changed files with 69 additions and 17 deletions
Download Patch File Download Diff File Expand all files Collapse all files

49
framework/src/android/net/NattKeepalivePacketData.java
View File

@@ -29,7 +29,9 @@ import android.system.OsConstants;
import com.android.net.module.util.IpUtils;
import java.net.Inet4Address;
import java.net.Inet6Address;
import java.net.InetAddress;
import java.net.UnknownHostException;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
import java.util.Objects;
@@ -38,6 +40,7 @@ import java.util.Objects;
@SystemApi
public final class NattKeepalivePacketData extends KeepalivePacketData implements Parcelable {
private static final int IPV4_HEADER_LENGTH = 20;
private static final int IPV6_HEADER_LENGTH = 40;
private static final int UDP_HEADER_LENGTH = 8;
// This should only be constructed via static factory methods, such as
@@ -59,13 +62,25 @@ public final class NattKeepalivePacketData extends KeepalivePacketData implement
throw new InvalidPacketException(ERROR_INVALID_PORT);
}
if (!(srcAddress instanceof Inet4Address) || !(dstAddress instanceof Inet4Address)) {
// Convert IPv4 mapped v6 address to v4 if any.
final InetAddress srcAddr, dstAddr;
try {
srcAddr = InetAddress.getByAddress(srcAddress.getAddress());
dstAddr = InetAddress.getByAddress(dstAddress.getAddress());
} catch (UnknownHostException e) {
throw new InvalidPacketException(ERROR_INVALID_IP_ADDRESS);
}
if (srcAddr instanceof Inet4Address && dstAddr instanceof Inet4Address) {
return nattKeepalivePacketv4(
(Inet4Address) srcAddress, srcPort,
(Inet4Address) dstAddress, dstPort);
(Inet4Address) srcAddr, srcPort, (Inet4Address) dstAddr, dstPort);
} else if (srcAddr instanceof Inet6Address && dstAddress instanceof Inet6Address) {
return nattKeepalivePacketv6(
(Inet6Address) srcAddr, srcPort, (Inet6Address) dstAddr, dstPort);
} else {
// Destination address and source address should be the same IP family.
throw new InvalidPacketException(ERROR_INVALID_IP_ADDRESS);
}
}
private static NattKeepalivePacketData nattKeepalivePacketv4(
@@ -82,14 +97,14 @@ public final class NattKeepalivePacketData extends KeepalivePacketData implement
// /proc/sys/net/ipv4/ip_default_ttl. Use hard-coded 64 for simplicity.
buf.put((byte) 64); // TTL
buf.put((byte) OsConstants.IPPROTO_UDP);
int ipChecksumOffset = buf.position();
final int ipChecksumOffset = buf.position();
buf.putShort((short) 0); // IP checksum
buf.put(srcAddress.getAddress());
buf.put(dstAddress.getAddress());
buf.putShort((short) srcPort);
buf.putShort((short) dstPort);
buf.putShort((short) (UDP_HEADER_LENGTH + 1)); // UDP length
int udpChecksumOffset = buf.position();
final int udpChecksumOffset = buf.position();
buf.putShort((short) 0); // UDP checksum
buf.put((byte) 0xff); // NAT-T keepalive
buf.putShort(ipChecksumOffset, IpUtils.ipChecksum(buf, 0));
@@ -98,6 +113,30 @@ public final class NattKeepalivePacketData extends KeepalivePacketData implement
return new NattKeepalivePacketData(srcAddress, srcPort, dstAddress, dstPort, buf.array());
}
private static NattKeepalivePacketData nattKeepalivePacketv6(
Inet6Address srcAddress, int srcPort, Inet6Address dstAddress, int dstPort)
throws InvalidPacketException {
final ByteBuffer buf = ByteBuffer.allocate(IPV6_HEADER_LENGTH + UDP_HEADER_LENGTH + 1);
buf.order(ByteOrder.BIG_ENDIAN);
buf.putInt(0x60000000); // IP version, traffic class and flow label
buf.putShort((short) (UDP_HEADER_LENGTH + 1)); // Payload length
buf.put((byte) OsConstants.IPPROTO_UDP); // Next header
// For native ipv6, this hop limit value should use the per interface v6 hoplimit sysctl.
// For 464xlat, this value should use the v4 ttl sysctl.
// Either way, for simplicity, just hard code 64.
buf.put((byte) 64); // Hop limit
buf.put(srcAddress.getAddress());
buf.put(dstAddress.getAddress());
// UDP
buf.putShort((short) srcPort);
buf.putShort((short) dstPort);
buf.putShort((short) (UDP_HEADER_LENGTH + 1)); // UDP length = Payload length
final int udpChecksumOffset = buf.position();
buf.putShort((short) 0); // UDP checksum
buf.put((byte) 0xff); // NAT-T keepalive. 1 byte of data
buf.putShort(udpChecksumOffset, IpUtils.udpChecksum(buf, 0, IPV6_HEADER_LENGTH));
return new NattKeepalivePacketData(srcAddress, srcPort, dstAddress, dstPort, buf.array());
}
/** Parcelable Implementation */
public int describeContents() {
return 0;

24
tests/common/java/android/net/NattKeepalivePacketDataTest.kt
View File

@@ -46,6 +46,8 @@ class NattKeepalivePacketDataTest {
private val TEST_SRC_ADDRV4 = "198.168.0.2".address()
private val TEST_DST_ADDRV4 = "198.168.0.1".address()
private val TEST_ADDRV6 = "2001:db8::1".address()
private val TEST_ADDRV4MAPPEDV6 = "::ffff:1.2.3.4".address()
private val TEST_ADDRV4 = "1.2.3.4".address()
private fun String.address() = InetAddresses.parseNumericAddress(this)
private fun nattKeepalivePacket(
@@ -83,6 +85,28 @@ class NattKeepalivePacketDataTest {
}
}
@Test @IgnoreUpTo(Build.VERSION_CODES.R)
fun testConstructor_afterR() {
// v4 mapped v6 will be translated to a v4 address.
assertFailsWith<InvalidPacketException> {
nattKeepalivePacket(srcAddress = TEST_ADDRV6, dstAddress = TEST_ADDRV4MAPPEDV6)
}
assertFailsWith<InvalidPacketException> {
nattKeepalivePacket(srcAddress = TEST_ADDRV4MAPPEDV6, dstAddress = TEST_ADDRV6)
}
// Both src and dst address will be v4 after translation, so it won't cause exception.
val packet1 = nattKeepalivePacket(
dstAddress = TEST_ADDRV4MAPPEDV6, srcAddress = TEST_ADDRV4MAPPEDV6)
assertEquals(TEST_ADDRV4, packet1.srcAddress)
assertEquals(TEST_ADDRV4, packet1.dstAddress)
// Packet with v6 src and v6 dst address is valid.
val packet2 = nattKeepalivePacket(srcAddress = TEST_ADDRV6, dstAddress = TEST_ADDRV6)
assertEquals(TEST_ADDRV6, packet2.srcAddress)
assertEquals(TEST_ADDRV6, packet2.dstAddress)
}
@Test @IgnoreUpTo(Build.VERSION_CODES.Q)
fun testParcel() {
assertParcelingIsLossless(nattKeepalivePacket())

11
tests/unit/java/com/android/server/ConnectivityServiceTest.java
View File

@@ -6856,10 +6856,6 @@ public class ConnectivityServiceTest {
ka = mCm.startNattKeepalive(myNet, validKaInterval, callback, myIPv6, 1234, dstIPv4);
callback.expectError(PacketKeepalive.ERROR_INVALID_IP_ADDRESS);
// NAT-T is only supported for IPv4.
ka = mCm.startNattKeepalive(myNet, validKaInterval, callback, myIPv6, 1234, dstIPv6);
callback.expectError(PacketKeepalive.ERROR_INVALID_IP_ADDRESS);
ka = mCm.startNattKeepalive(myNet, validKaInterval, callback, myIPv4, 123456, dstIPv4);
callback.expectError(PacketKeepalive.ERROR_INVALID_PORT);
@@ -7010,13 +7006,6 @@ public class ConnectivityServiceTest {
callback.expectError(SocketKeepalive.ERROR_INVALID_IP_ADDRESS);
}
// NAT-T is only supported for IPv4.
try (SocketKeepalive ka = mCm.createSocketKeepalive(
myNet, testSocket, myIPv6, dstIPv6, executor, callback)) {
ka.start(validKaInterval);
callback.expectError(SocketKeepalive.ERROR_INVALID_IP_ADDRESS);
}
// Basic check before testing started keepalive.
try (SocketKeepalive ka = mCm.createSocketKeepalive(
myNet, testSocket, myIPv4, dstIPv4, executor, callback)) {