Merge "Make RtNetlinkLinkMessage class immutable after creation" into main am: e7f5ac9d2f
Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/3266574
Change-Id: I420d02d2edc9ac53d2021e03b76495c04ba69c88
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>
diff --git a/staticlibs/device/com/android/net/module/util/netlink/RtNetlinkLinkMessage.java b/staticlibs/device/com/android/net/module/util/netlink/RtNetlinkLinkMessage.java
index 0c49edc..72c770a 100644
--- a/staticlibs/device/com/android/net/module/util/netlink/RtNetlinkLinkMessage.java
+++ b/staticlibs/device/com/android/net/module/util/netlink/RtNetlinkLinkMessage.java
@@ -16,6 +16,8 @@
package com.android.net.module.util.netlink;
+import static com.android.net.module.util.NetworkStackConstants.ETHER_ADDR_LEN;
+
import android.net.MacAddress;
import android.system.OsConstants;
@@ -24,6 +26,7 @@
import androidx.annotation.VisibleForTesting;
import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
/**
* A NetlinkMessage subclass for rtnetlink link messages.
@@ -46,29 +49,55 @@
public static final short IN6_ADDR_GEN_MODE_NONE = 1;
- private int mMtu;
- @NonNull
- private StructIfinfoMsg mIfinfomsg;
- @Nullable
- private MacAddress mHardwareAddress;
- @Nullable
- private String mInterfaceName;
+ // The maximum buffer size to hold an interface name including the null-terminator '\0'.
+ private static final int IFNAMSIZ = 16;
+ // The default value of MTU, which means the MTU is unspecified.
+ private static final int DEFAULT_MTU = 0;
- private RtNetlinkLinkMessage(@NonNull StructNlMsgHdr header) {
- super(header);
- mIfinfomsg = null;
- mMtu = 0;
- mHardwareAddress = null;
- mInterfaceName = null;
+ @NonNull
+ private final StructIfinfoMsg mIfinfomsg;
+ private final int mMtu;
+ @Nullable
+ private final MacAddress mHardwareAddress;
+ @Nullable
+ private final String mInterfaceName;
+
+ /**
+ * Creates an {@link RtNetlinkLinkMessage} instance.
+ *
+ * <p>This method validates the arguments and returns {@code null} if any of them are invalid.
+ * nlmsghdr's nlmsg_len will be updated to the correct length before creation.
+ *
+ * @param nlmsghdr The Netlink message header. Must not be {@code null}.
+ * @param ifinfomsg The interface information message. Must not be {@code null}.
+ * @param mtu The Maximum Transmission Unit (MTU) value for the link.
+ * @param hardwareAddress The hardware address (MAC address) of the link. May be {@code null}.
+ * @param interfaceName The name of the interface. May be {@code null}.
+ * @return A new {@link RtNetlinkLinkMessage} instance, or {@code null} if the input arguments
+ * are invalid.
+ */
+ @Nullable
+ public static RtNetlinkLinkMessage build(@NonNull StructNlMsgHdr nlmsghdr,
+ @NonNull StructIfinfoMsg ifinfomsg, int mtu, @Nullable MacAddress hardwareAddress,
+ @Nullable String interfaceName) {
+ if (mtu < 0) {
+ return null;
+ }
+ if (interfaceName != null
+ && (interfaceName.isEmpty() || interfaceName.length() + 1 > IFNAMSIZ)) {
+ return null;
+ }
+
+ nlmsghdr.nlmsg_len = calculateMessageLength(mtu, hardwareAddress, interfaceName);
+ return new RtNetlinkLinkMessage(nlmsghdr, ifinfomsg, mtu, hardwareAddress, interfaceName);
}
- @VisibleForTesting
- public RtNetlinkLinkMessage(@NonNull StructNlMsgHdr nlmsghdr,
- int mtu, @NonNull StructIfinfoMsg ifinfomsg, @NonNull MacAddress hardwareAddress,
- @NonNull String interfaceName) {
+ private RtNetlinkLinkMessage(@NonNull StructNlMsgHdr nlmsghdr,
+ @NonNull StructIfinfoMsg ifinfomsg, int mtu, @Nullable MacAddress hardwareAddress,
+ @Nullable String interfaceName) {
super(nlmsghdr);
- mMtu = mtu;
mIfinfomsg = ifinfomsg;
+ mMtu = mtu;
mHardwareAddress = hardwareAddress;
mInterfaceName = interfaceName;
}
@@ -102,33 +131,46 @@
@Nullable
public static RtNetlinkLinkMessage parse(@NonNull final StructNlMsgHdr header,
@NonNull final ByteBuffer byteBuffer) {
- final RtNetlinkLinkMessage linkMsg = new RtNetlinkLinkMessage(header);
-
- linkMsg.mIfinfomsg = StructIfinfoMsg.parse(byteBuffer);
- if (linkMsg.mIfinfomsg == null) return null;
+ final StructIfinfoMsg ifinfoMsg = StructIfinfoMsg.parse(byteBuffer);
+ if (ifinfoMsg == null) {
+ return null;
+ }
// IFLA_MTU
+ int mtu = DEFAULT_MTU;
final int baseOffset = byteBuffer.position();
StructNlAttr nlAttr = StructNlAttr.findNextAttrOfType(IFLA_MTU, byteBuffer);
if (nlAttr != null) {
- linkMsg.mMtu = nlAttr.getValueAsInt(0 /* default value */);
+ mtu = nlAttr.getValueAsInt(DEFAULT_MTU);
}
// IFLA_ADDRESS
+ MacAddress hardwareAddress = null;
byteBuffer.position(baseOffset);
nlAttr = StructNlAttr.findNextAttrOfType(IFLA_ADDRESS, byteBuffer);
if (nlAttr != null) {
- linkMsg.mHardwareAddress = nlAttr.getValueAsMacAddress();
+ hardwareAddress = nlAttr.getValueAsMacAddress();
}
// IFLA_IFNAME
+ String interfaceName = null;
byteBuffer.position(baseOffset);
nlAttr = StructNlAttr.findNextAttrOfType(IFLA_IFNAME, byteBuffer);
if (nlAttr != null) {
- linkMsg.mInterfaceName = nlAttr.getValueAsString();
+ interfaceName = nlAttr.getValueAsString();
}
- return linkMsg;
+ return new RtNetlinkLinkMessage(header, ifinfoMsg, mtu, hardwareAddress, interfaceName);
+ }
+
+ /**
+ * Write a rtnetlink link message to {@link byte} array.
+ */
+ public byte[] pack(ByteOrder order) {
+ byte[] bytes = new byte[mHeader.nlmsg_len];
+ ByteBuffer buffer = ByteBuffer.wrap(bytes).order(order);
+ pack(buffer);
+ return bytes;
}
/**
@@ -136,10 +178,10 @@
*/
@VisibleForTesting
protected void pack(ByteBuffer byteBuffer) {
- getHeader().pack(byteBuffer);
+ mHeader.pack(byteBuffer);
mIfinfomsg.pack(byteBuffer);
- if (mMtu != 0) {
+ if (mMtu != DEFAULT_MTU) {
final StructNlAttr mtu = new StructNlAttr(IFLA_MTU, mMtu);
mtu.pack(byteBuffer);
}
@@ -153,11 +195,34 @@
}
}
+ /**
+ * Calculate the byte length of the packed buffer.
+ */
+ private static int calculateMessageLength(int mtu, MacAddress hardwareAddress,
+ String interfaceName) {
+ int length = StructNlMsgHdr.STRUCT_SIZE + StructIfinfoMsg.STRUCT_SIZE;
+
+ if (mtu != DEFAULT_MTU) {
+ length += NetlinkConstants.alignedLengthOf(StructNlAttr.NLA_HEADERLEN + Integer.BYTES);
+ }
+ if (hardwareAddress != null) {
+ length += NetlinkConstants.alignedLengthOf(
+ StructNlAttr.NLA_HEADERLEN + ETHER_ADDR_LEN);
+ }
+ if (interfaceName != null) {
+ length += NetlinkConstants.alignedLengthOf(
+ // The string should be end with '\0', so the length should plus 1.
+ StructNlAttr.NLA_HEADERLEN + interfaceName.length() + 1);
+ }
+
+ return length;
+ }
+
@Override
public String toString() {
return "RtNetlinkLinkMessage{ "
+ "nlmsghdr{" + mHeader.toString(OsConstants.NETLINK_ROUTE) + "}, "
- + "Ifinfomsg{" + mIfinfomsg.toString() + "}, "
+ + "Ifinfomsg{" + mIfinfomsg + "}, "
+ "Hardware Address{" + mHardwareAddress + "}, "
+ "MTU{" + mMtu + "}, "
+ "Ifname{" + mInterfaceName + "} "
diff --git a/staticlibs/tests/unit/src/com/android/net/module/util/netlink/RtNetlinkLinkMessageTest.java b/staticlibs/tests/unit/src/com/android/net/module/util/netlink/RtNetlinkLinkMessageTest.java
index 9db63db..afe220f 100644
--- a/staticlibs/tests/unit/src/com/android/net/module/util/netlink/RtNetlinkLinkMessageTest.java
+++ b/staticlibs/tests/unit/src/com/android/net/module/util/netlink/RtNetlinkLinkMessageTest.java
@@ -124,14 +124,14 @@
}
private static final String RTM_NEWLINK_PACK_HEX =
- "34000000100000000000000000000000" // struct nlmsghr
+ "40000000100000000000000000000000" // struct nlmsghr
+ "000001001E0000000210000000000000" // struct ifinfo
+ "08000400DC050000" // IFLA_MTU
+ "0A00010092C3E3C9374E0000" // IFLA_ADDRESS
+ "0A000300776C616E30000000"; // IFLA_IFNAME(wlan0)
@Test
- public void testPackRtmNewLink() {
+ public void testParseAndPackRtmNewLink() {
final ByteBuffer byteBuffer = toByteBuffer(RTM_NEWLINK_PACK_HEX);
byteBuffer.order(ByteOrder.LITTLE_ENDIAN); // For testing.
final NetlinkMessage msg = NetlinkMessage.parse(byteBuffer, NETLINK_ROUTE);
@@ -145,6 +145,21 @@
assertEquals(RTM_NEWLINK_PACK_HEX, HexDump.toHexString(packBuffer.array()));
}
+ @Test
+ public void testPackRtmNewLink() {
+ final RtNetlinkLinkMessage linkMsg = RtNetlinkLinkMessage.build(
+ // nlmsg_len will be updated inside create() method, so it's ok to set 0 here.
+ new StructNlMsgHdr(0 /*nlmsg_len*/, (short) 0x10, (short) 0, 0),
+ new StructIfinfoMsg((byte) 0, (short) 1, 0x1e, 0x1002, 0),
+ 1500,
+ MacAddress.fromString("92:c3:e3:c9:37:4e"),
+ "wlan0");
+ assertNotNull(linkMsg);
+
+ final byte[] packBytes = linkMsg.pack(ByteOrder.LITTLE_ENDIAN);
+ assertEquals(RTM_NEWLINK_PACK_HEX, HexDump.toHexString(packBytes));
+ }
+
private static final String RTM_NEWLINK_TRUNCATED_HEX =
"54000000100000000000000000000000" // struct nlmsghr
+ "000001001E0000000210000000000000" // struct ifinfo