Added interfaces for reading and writing packets and recognising which

contact originated an incoming connection, and an implementation of the PacketWriter interface.
2026-02-13 19:29:06 +01:00 · 2011-08-09 16:15:25 +01:00
parent 18654f1514
commit e9d0021f56
8 changed files with 351 additions and 1 deletions
--- a/test/net/sf/briar/transport/PacketWriterImplTest.java
+++ b/test/net/sf/briar/transport/PacketWriterImplTest.java
@@ -0,0 +1,136 @@
+package net.sf.briar.transport;
+
+import java.io.ByteArrayOutputStream;
+import java.util.Arrays;
+
+import javax.crypto.Mac;
+
+import junit.framework.TestCase;
+import net.sf.briar.api.crypto.CryptoComponent;
+import net.sf.briar.api.transport.PacketWriter;
+import net.sf.briar.crypto.CryptoModule;
+import net.sf.briar.util.StringUtils;
+
+import org.junit.Test;
+
+import com.google.inject.Guice;
+import com.google.inject.Injector;
+
+public class PacketWriterImplTest extends TestCase {
+
+	private final Mac mac;
+
+	public PacketWriterImplTest() throws Exception {
+		super();
+		Injector i = Guice.createInjector(new CryptoModule());
+		CryptoComponent crypto = i.getInstance(CryptoComponent.class);
+		mac = crypto.getMac();
+		mac.init(crypto.generateSecretKey());
+	}
+
+	@Test
+	public void testFirstWriteTriggersTag() throws Exception {
+		ByteArrayOutputStream out = new ByteArrayOutputStream();
+		PacketWriter p = new PacketWriterImpl(out, mac, 0, 0L);
+		p.getOutputStream().write(0);
+		// There should be 16 zero bytes for the tag, 1 for the byte written
+		assertTrue(Arrays.equals(new byte[17], out.toByteArray()));
+	}
+
+	@Test
+	public void testNextPacketAfterWriteTriggersMac() throws Exception {
+		// Calculate what the MAC should be
+		mac.update(new byte[17]);
+		byte[] expectedMac = mac.doFinal();
+		// Check that the PacketWriter calculates and writes the correct MAC
+		ByteArrayOutputStream out = new ByteArrayOutputStream();
+		PacketWriter p = new PacketWriterImpl(out, mac, 0, 0L);
+		p.getOutputStream().write(0);
+		p.nextPacket();
+		byte[] written = out.toByteArray();
+		assertEquals(17 + expectedMac.length, written.length);
+		byte[] actualMac = new byte[expectedMac.length];
+		System.arraycopy(written, 17, actualMac, 0, actualMac.length);
+		assertTrue(Arrays.equals(expectedMac, actualMac));
+	}
+
+	@Test
+	public void testExtraCallsToNextPacketDoNothing() throws Exception {
+		// Calculate what the MAC should be
+		mac.update(new byte[17]);
+		byte[] expectedMac = mac.doFinal();
+		// Check that the PacketWriter calculates and writes the correct MAC
+		ByteArrayOutputStream out = new ByteArrayOutputStream();
+		PacketWriter p = new PacketWriterImpl(out, mac, 0, 0L);
+		// Initial calls to nextPacket() should have no effect
+		p.nextPacket();
+		p.nextPacket();
+		p.nextPacket();
+		p.getOutputStream().write(0);
+		p.nextPacket();
+		// Extra calls to nextPacket() should have no effect
+		p.nextPacket();
+		p.nextPacket();
+		p.nextPacket();
+		byte[] written = out.toByteArray();
+		assertEquals(17 + expectedMac.length, written.length);
+		byte[] actualMac = new byte[expectedMac.length];
+		System.arraycopy(written, 17, actualMac, 0, actualMac.length);
+		assertTrue(Arrays.equals(expectedMac, actualMac));
+	}
+
+	@Test
+	public void testPacketNumberIsIncremented() throws Exception {
+		byte[] expectedTag = StringUtils.fromHexString(
+				"0000" // 16 bits reserved
+				+ "F00D" // 16 bits for the transport ID
+				+ "DEADBEEF" // 32 bits for the connection number
+				+ "00000000" // 32 bits for the packet number
+				+ "00000000" // 32 bits for the block number
+		);
+		byte[] expectedTag1 = StringUtils.fromHexString(
+				"0000" // 16 bits reserved
+				+ "F00D" // 16 bits for the transport ID
+				+ "DEADBEEF" // 32 bits for the connection number
+				+ "00000001" // 32 bits for the packet number
+				+ "00000000" // 32 bits for the block number
+		);
+		// Calculate what the MAC on the first packet should be
+		mac.update(expectedTag);
+		mac.update((byte) 0);
+		byte[] expectedMac = mac.doFinal();
+		// Calculate what the MAC on the second packet should be
+		mac.update(expectedTag1);
+		mac.update((byte) 0);
+		byte[] expectedMac1 = mac.doFinal();
+		// Check that the PacketWriter writes the correct tags and MACs
+		ByteArrayOutputStream out = new ByteArrayOutputStream();
+		PacketWriter p = new PacketWriterImpl(out, mac, 0xF00D, 0xDEADBEEFL);
+		// Packet one
+		p.getOutputStream().write(0);
+		p.nextPacket();
+		// Packet two
+		p.getOutputStream().write(0);
+		p.nextPacket();
+		byte[] written = out.toByteArray();
+		assertEquals(17 + expectedMac.length + 17 + expectedMac1.length,
+				written.length);
+		// Check the first packet's tag
+		byte[] actualTag = new byte[16];
+		System.arraycopy(written, 0, actualTag, 0, 16);
+		assertTrue(Arrays.equals(expectedTag, actualTag));
+		// Check the first packet's MAC
+		byte[] actualMac = new byte[expectedMac.length];
+		System.arraycopy(written, 17, actualMac, 0, actualMac.length);
+		assertTrue(Arrays.equals(expectedMac, actualMac));
+		// Check the second packet's tag
+		byte[] actualTag1 = new byte[16];
+		System.arraycopy(written, 17 + expectedMac.length, actualTag1, 0, 16);
+		assertTrue(Arrays.equals(expectedTag1, actualTag1));
+		// Check the second packet's MAC
+		byte[] actualMac1 = new byte[expectedMac1.length];
+		System.arraycopy(written, 17 + expectedMac.length + 17, actualMac1, 0,
+				actualMac1.length);
+		assertTrue(Arrays.equals(expectedMac1, actualMac1));
+	}
+}