/*
* Created on 17-Jan-2006
* Created by Paul Gardner
* Copyright (C) 2006 Aelitis, All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* AELITIS, SAS au capital de 46,603.30 euros
* 8 Allee Lenotre, La Grille Royale, 78600 Le Mesnil le Roi, France.
*
*/
package com.aelitis.azureus.core.networkmanager.impl;
import java.io.IOException;
import java.math.BigInteger;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.util.*;
import javax.crypto.Cipher;
import javax.crypto.KeyAgreement;
import javax.crypto.interfaces.DHPublicKey;
import javax.crypto.spec.DHParameterSpec;
import javax.crypto.spec.DHPublicKeySpec;
import javax.crypto.spec.SecretKeySpec;
import org.gudy.azureus2.core3.config.COConfigurationManager;
import org.gudy.azureus2.core3.config.ParameterListener;
import org.gudy.azureus2.core3.logging.LogAlert;
import org.gudy.azureus2.core3.logging.LogEvent;
import org.gudy.azureus2.core3.logging.LogIDs;
import org.gudy.azureus2.core3.logging.Logger;
import org.gudy.azureus2.core3.util.AEMonitor;
import org.gudy.azureus2.core3.util.AddressUtils;
import org.gudy.azureus2.core3.util.ByteFormatter;
import org.gudy.azureus2.core3.util.Debug;
import org.gudy.azureus2.core3.util.HashWrapper;
import org.gudy.azureus2.core3.util.LightHashMap;
import org.gudy.azureus2.core3.util.RandomUtils;
import org.gudy.azureus2.core3.util.SHA1Hasher;
import org.gudy.azureus2.core3.util.SystemTime;
import com.aelitis.azureus.core.networkmanager.NetworkManager;
import com.aelitis.azureus.core.util.bloom.BloomFilter;
import com.aelitis.azureus.core.util.bloom.BloomFilterFactory;
public class
ProtocolDecoderPHE
extends ProtocolDecoder
{
private static final LogIDs LOGID = LogIDs.NWMAN;
private static final byte CRYPTO_PLAIN = 0x01;
private static final byte CRYPTO_RC4 = 0x02;
private static final byte CRYPTO_XOR = 0x04;
private static final byte CRYPTO_AES = 0x08;
//private static final String DH_P = "92d862b3a95bff4e6cbdce3a266ff4b46e6e1ecad76c0a877d92a3dae4999e6414efde56fc14d1cca6d5408a8ef9ea248389168876b6e8f4503845dfe373549f";
//private static final String DH_G = "4383b53ee650fd73e41e8c9e8527997ab8cb41e1cbd73ac7685493e1e5d091e3e3789dea03ab9d5b2c368faa617bb30e427cbaeb23c268edb38eb8c747756080";
// private static final String DH_P = "f3f90c790c63b119f9c1be43fdb12dc6ed6f26325999c01ba6ed373e75d6b2dee8d1c0475652a987c8df57b23d395bdb142be316d780b9361f85629535030873";
private static final String DH_P = "FFFFFFFFFFFFFFFFC90FDAA22168C234C4C6628B80DC1CD129024E088A67CC74020BBEA63B139B22514A08798E3404DDEF9519B3CD3A431B302B0A6DF25F14374FE1356D6D51C245E485B576625E7EC6F44C42E9A63A36210000000000090563";
private static final String DH_G = "02";
private static final int DH_L = 160;
private static final int DH_SIZE_BYTES = DH_P.length()/2;
public static final int MIN_INCOMING_INITIAL_PACKET_SIZE = DH_SIZE_BYTES;
private static final BigInteger DH_P_BI = new BigInteger( DH_P, 16 );
private static final BigInteger DH_G_BI = new BigInteger( DH_G, 16 );
private static KeyPairGenerator dh_key_generator;
private static long last_dh_incoming_key_generate;
private static final int BLOOM_RECREATE = 30*1000;
private static final int BLOOM_INCREASE = 1000;
private static BloomFilter generate_bloom = BloomFilterFactory.createAddRemove4Bit(BLOOM_INCREASE);
private static long generate_bloom_create_time = SystemTime.getCurrentTime();
private static boolean crypto_setup_done;
private static boolean crypto_ok;
//private static boolean aes_ok;
/*
private static final String AES_STREAM_ALG = "AES";
private static final String AES_STREAM_CIPHER = "AES/CFB8/NoPadding";
private static final int AES_STREAM_KEY_SIZE = 128;
private static final int AES_STREAM_KEY_SIZE_BYTES = AES_STREAM_KEY_SIZE/8;
*/
//private static final byte[] AES_STREAM_IV =
// { (byte)0x15, (byte)0xE0, (byte)0x6B, (byte)0x7E, (byte)0x98, (byte)0x59, (byte)0xE4, (byte)0xA7,
// (byte)0x34, (byte)0x66, (byte)0xAD, (byte)0x48, (byte)0x35, (byte)0xE2, (byte)0xD0, (byte)0x24 };
private static final String RC4_STREAM_ALG = "RC4";
private static final String RC4_STREAM_CIPHER = "RC4";
private static final int RC4_STREAM_KEY_SIZE = 128;
private static final int RC4_STREAM_KEY_SIZE_BYTES = RC4_STREAM_KEY_SIZE/8;
private static final int PADDING_MAX = 512;
private static final int PADDING_MAX_NORMAL = PADDING_MAX;
private static final int PADDING_MAX_LIMITED = 128;
public static int
getMaxIncomingInitialPacketSize(
boolean min_overheads )
{
return( MIN_INCOMING_INITIAL_PACKET_SIZE + (min_overheads?PADDING_MAX_LIMITED:PADDING_MAX_NORMAL)/2 );
}
private static Random random = RandomUtils.SECURE_RANDOM;
private static Map global_shared_secrets = new LightHashMap();
private static boolean
cryptoSetup()
{
synchronized( global_shared_secrets ){
if ( crypto_setup_done ){
return( crypto_ok );
}
crypto_setup_done = true;
try{
DHParameterSpec dh_param_spec = new DHParameterSpec( DH_P_BI, DH_G_BI, DH_L );
dh_key_generator = KeyPairGenerator.getInstance("DH");
dh_key_generator.initialize(dh_param_spec);
dh_key_generator.generateKeyPair();
byte[] rc4_test_secret = new byte[RC4_STREAM_KEY_SIZE_BYTES];
SecretKeySpec rc4_test_secret_key_spec = new SecretKeySpec(rc4_test_secret, 0, RC4_STREAM_KEY_SIZE_BYTES, RC4_STREAM_ALG );
TransportCipher rc4_cipher = new TransportCipher( RC4_STREAM_CIPHER, Cipher.ENCRYPT_MODE, rc4_test_secret_key_spec );
rc4_cipher = new TransportCipher( RC4_STREAM_CIPHER, Cipher.DECRYPT_MODE, rc4_test_secret_key_spec );
/*
try{
byte[] aes_test_secret = new byte[AES_STREAM_KEY_SIZE_BYTES];
SecretKeySpec aes_test_secret_key_spec = new SecretKeySpec(aes_test_secret, 0, AES_STREAM_KEY_SIZE_BYTES, AES_STREAM_ALG );
AlgorithmParameterSpec spec = new IvParameterSpec( aes_test_secret );
TCPTransportCipher aes_cipher = new TCPTransportCipher( AES_STREAM_CIPHER, Cipher.ENCRYPT_MODE, aes_test_secret_key_spec, spec );
aes_cipher = new TCPTransportCipher( AES_STREAM_CIPHER, Cipher.DECRYPT_MODE, aes_test_secret_key_spec, spec );
aes_ok = true;
}catch( Throwable e ){
Logger.log( new LogEvent(LOGID, "AES Unavailable", e ));
}
*/
crypto_ok = true;
if (Logger.isEnabled()){
Logger.log( new LogEvent(LOGID, "PHE crypto initialised" ));
}
}catch( NoClassDefFoundError e ){
// running without PHE classes, not such a severe error
Logger.log( new LogEvent(LOGID, "PHE crypto disabled as classes unavailable" ));
crypto_ok = false;
}catch( Throwable e ){
Logger.log( new LogEvent(LOGID, "PHE crypto initialisation failed", e ));
crypto_ok = false;
}
return( crypto_ok );
}
}
public static boolean
isCryptoOK()
{
return( cryptoSetup());
}
public static void
addSecretsSupport(
byte[][] secrets )
{
for (int i=0;i<secrets.length;i++){
SHA1Hasher hasher = new SHA1Hasher();
hasher.update( REQ2_IV );
hasher.update( secrets[i] );
byte[] encoded = hasher.getDigest();
synchronized( global_shared_secrets ){
global_shared_secrets.put( new HashWrapper( encoded ), secrets[i] );
}
}
}
public static void
removeSecretsSupport(
byte[][] secrets )
{
for (int i=0;i<secrets.length;i++){
SHA1Hasher hasher = new SHA1Hasher();
hasher.update( REQ2_IV );
hasher.update( secrets[i] );
byte[] encoded = hasher.getDigest();
synchronized( global_shared_secrets ){
global_shared_secrets.remove( new HashWrapper( encoded ));
}
}
}
// private static final byte SUPPORTED_PROTOCOLS = (byte)((aes_ok?CRYPTO_AES:0) | CRYPTO_RC4 | CRYPTO_XOR | CRYPTO_PLAIN );
private static final byte SUPPORTED_PROTOCOLS = (byte)(CRYPTO_RC4 | CRYPTO_PLAIN );
private static byte MIN_CRYPTO;
static{
COConfigurationManager.addAndFireParameterListeners(
new String[]{ "network.transport.encrypted.min_level" },
new ParameterListener()
{
public void
parameterChanged(
String ignore )
{
if ( NetworkManager.REQUIRE_CRYPTO_HANDSHAKE && !isCryptoOK() ){
Logger.log( new LogAlert(true,LogAlert.AT_ERROR,"Connection encryption unavailable, please update your Java version" ));
}
String min = COConfigurationManager.getStringParameter( "network.transport.encrypted.min_level");
if ( min.equals( "XOR" )){
MIN_CRYPTO = CRYPTO_XOR | CRYPTO_RC4 | CRYPTO_AES;
}else if ( min.equals( "RC4" )){
MIN_CRYPTO = CRYPTO_RC4 | CRYPTO_AES;
}else if ( min.equals( "AES" )){
MIN_CRYPTO = CRYPTO_AES;
}else{
MIN_CRYPTO = CRYPTO_PLAIN | CRYPTO_XOR | CRYPTO_RC4 | CRYPTO_AES;
}
MIN_CRYPTO = (byte)(MIN_CRYPTO & SUPPORTED_PROTOCOLS);
}
});
}
private static final int PS_OUTBOUND_1 = 0;
private static final int PS_OUTBOUND_2 = 1;
private static final int PS_OUTBOUND_3 = 2;
private static final int PS_OUTBOUND_4 = 3;
private static final int PS_INBOUND_1 = 10;
private static final int PS_INBOUND_2 = 11;
private static final int PS_INBOUND_3 = 12;
private static final int PS_INBOUND_4 = 13;
public static final byte[] KEYA_IV = "keyA".getBytes();
public static final byte[] KEYB_IV = "keyB".getBytes();
public static final byte[] REQ1_IV = "req1".getBytes();
public static final byte[] REQ2_IV = "req2".getBytes();
public static final byte[] REQ3_IV = "req3".getBytes();
public static final byte[] VC = { 0,0,0,0,0,0,0,0};
private TransportHelper transport;
private ByteBuffer write_buffer;
private ByteBuffer read_buffer;
private ProtocolDecoderAdapter adapter;
private KeyAgreement key_agreement;
private byte[] dh_public_key_bytes;
private byte[] shared_secret;
private byte[] secret_bytes;
private ByteBuffer initial_data_out;
private ByteBuffer initial_data_in;
private TransportCipher write_cipher;
private TransportCipher read_cipher;
private byte[] padding_skip_marker;
private byte my_supported_protocols;
private byte selected_protocol;
private boolean outbound;
private int protocol_state;
private int protocol_substate;
private boolean handshake_complete;
private int bytes_read;
private int bytes_written;
private long last_read_time = SystemTime.getCurrentTime();
private TransportHelperFilter filter;
private boolean delay_outbound_4;
private boolean processing_complete;
private AEMonitor process_mon = new AEMonitor( "ProtocolDecoderPHE:process" );
public
ProtocolDecoderPHE(
TransportHelper _transport,
byte[][] _shared_secrets,
ByteBuffer _header,
ByteBuffer _initial_data,
ProtocolDecoderAdapter _adapter )
throws IOException
{
super( false );
if ( !isCryptoOK()){
throw( new IOException( "PHE crypto broken" ));
}
transport = _transport;
// scattering mode for the first KB, that should include the crypto handshake and part of the bittorrent handshake
transport.setScatteringMode(768+random.nextInt(256));
initial_data_out = _initial_data;
adapter = _adapter;
if ( _shared_secrets == null || _shared_secrets.length == 0 ){
shared_secret = new byte[0];
}else{
if ( _shared_secrets.length == 1 ){
shared_secret = _shared_secrets[0];
}else{
shared_secret = _shared_secrets[random.nextInt( _shared_secrets.length )];
}
// System.out.println( "outbound - using crypto secret " + ByteFormatter.encodeString( shared_secret ));
}
outbound = _header == null;
my_supported_protocols = SUPPORTED_PROTOCOLS;
if ( outbound ){
//if ( !NetworkManager.REQUIRE_CRYPTO_HANDSHAKE ){
// throw( new IOException( "Crypto encoder selected for outbound but crypto not required" ));
//}
// outbound connection, we require a certain minimal level of support
my_supported_protocols = MIN_CRYPTO;
}else{
// incoming. If we require crypto then we use minimum otherwise available
if ( NetworkManager.REQUIRE_CRYPTO_HANDSHAKE ){
my_supported_protocols = MIN_CRYPTO;
}
}
initCrypto();
try{
process_mon.enter();
transport.registerForReadSelects(
new TransportHelper.selectListener()
{
public boolean
selectSuccess(
TransportHelper helper,
Object attachment )
{
return( ProtocolDecoderPHE.this.selectSuccess( helper, attachment, false ));
}
public void
selectFailure(
TransportHelper helper,
Object attachment,
Throwable msg)
{
ProtocolDecoderPHE.this.selectFailure( helper, attachment, msg );
}
},
null );
transport.registerForWriteSelects(
new TransportHelper.selectListener()
{
public boolean
selectSuccess(
TransportHelper helper,
Object attachment )
{
return( ProtocolDecoderPHE.this.selectSuccess( helper, attachment, true ));
}
public void
selectFailure(
TransportHelper helper,
Object attachment,
Throwable msg)
{
ProtocolDecoderPHE.this.selectFailure( helper, attachment, msg );
}
},
null );
transport.pauseWriteSelects();
if ( outbound ){
protocol_state = PS_OUTBOUND_1;
transport.pauseReadSelects();
}else{
protocol_state = PS_INBOUND_1;
read_buffer = ByteBuffer.allocate( dh_public_key_bytes.length );
read_buffer.put( _header );
bytes_read += _header.limit();
}
}finally{
process_mon.exit();
}
process();
}
protected void
initCrypto()
throws IOException
{
try{
KeyPair key_pair = generateDHKeyPair( transport, outbound );
key_agreement = KeyAgreement.getInstance("DH");
key_agreement.init(key_pair.getPrivate());
DHPublicKey dh_public_key = (DHPublicKey)key_pair.getPublic();
BigInteger dh_y = dh_public_key.getY();
dh_public_key_bytes = bigIntegerToBytes( dh_y, DH_SIZE_BYTES );
}catch( Throwable e ){
throw( new IOException( Debug.getNestedExceptionMessage(e)));
}
}
protected void
completeDH(
byte[] buffer )
throws IOException
{
try{
BigInteger other_dh_y = bytesToBigInteger( buffer, 0, DH_SIZE_BYTES );
KeyFactory dh_key_factory = KeyFactory.getInstance("DH");
PublicKey other_public_key = dh_key_factory.generatePublic( new DHPublicKeySpec( other_dh_y, DH_P_BI, DH_G_BI ));
key_agreement.doPhase( other_public_key, true );
secret_bytes = key_agreement.generateSecret();
adapter.gotSecret( secret_bytes );
// System.out.println( "secret = " + ByteFormatter.encodeString( secret_bytes ));
}catch( Throwable e ){
throw( new IOException( Debug.getNestedExceptionMessage(e)));
}
}
protected void
setupCrypto()
throws IOException
{
try{
//"HASH('keyA', S, SKEY)" if you're A
//"HASH('keyB', S, SKEY)" if you're B
SHA1Hasher hasher = new SHA1Hasher();
hasher.update( KEYA_IV );
hasher.update( secret_bytes );
hasher.update( shared_secret );
byte[] a_key = hasher.getDigest();
hasher = new SHA1Hasher();
hasher.update( KEYB_IV );
hasher.update( secret_bytes );
hasher.update( shared_secret );
byte[] b_key = hasher.getDigest();
SecretKeySpec secret_key_spec_a = new SecretKeySpec( a_key, RC4_STREAM_ALG );
SecretKeySpec secret_key_spec_b = new SecretKeySpec( b_key, RC4_STREAM_ALG );
write_cipher = new TransportCipher( RC4_STREAM_CIPHER, Cipher.ENCRYPT_MODE, outbound?secret_key_spec_a:secret_key_spec_b );
read_cipher = new TransportCipher( RC4_STREAM_CIPHER, Cipher.DECRYPT_MODE, outbound?secret_key_spec_b:secret_key_spec_a );
}catch( Throwable e ){
e.printStackTrace();
throw( new IOException( Debug.getNestedExceptionMessage(e)));
}
}
/*
protected void
completeDH(
byte[] buffer )
throws IOException
{
try{
BigInteger other_dh_y = bytesToBigInteger( buffer, 0, DH_SIZE_BYTES );
KeyFactory dh_key_factory = KeyFactory.getInstance("DH");
PublicKey other_public_key = dh_key_factory.generatePublic( new DHPublicKeySpec( other_dh_y, DH_P_BI, DH_G_BI ));
key_agreement.doPhase( other_public_key, true );
byte[] secret_bytes_64 = key_agreement.generateSecret();
// we only want the first 32 bytes of the secret
secret_bytes = new byte[32];
System.arraycopy( secret_bytes_64, 0, secret_bytes, 0, 32 );
sha1_secret_bytes = new SHA1Simple().calculateHash( secret_bytes );
SecretKeySpec secret_key_spec_a = new SecretKeySpec( secret_bytes, 0, RC4_STREAM_KEY_SIZE_BYTES, RC4_STREAM_ALG );
SecretKeySpec secret_key_spec_b = new SecretKeySpec( secret_bytes, 16, RC4_STREAM_KEY_SIZE_BYTES, RC4_STREAM_ALG );
write_cipher = new TCPTransportCipher( RC4_STREAM_CIPHER, Cipher.ENCRYPT_MODE, outbound?secret_key_spec_a:secret_key_spec_b );
read_cipher = new TCPTransportCipher( RC4_STREAM_CIPHER, Cipher.DECRYPT_MODE, outbound?secret_key_spec_b:secret_key_spec_a );
}catch( Throwable e ){
throw( new IOException( Debug.getNestedExceptionMessage(e)));
}
}
*/
protected void
handshakeComplete()
throws IOException
{
if ( selected_protocol == CRYPTO_PLAIN ){
filter = new TransportHelperFilterTransparent( transport, true );
}else if ( selected_protocol == CRYPTO_XOR ){
filter = new TransportHelperFilterStreamXOR( transport, secret_bytes );
}else if ( selected_protocol == CRYPTO_RC4 ){
filter = new TransportHelperFilterStreamCipher(
transport,
read_cipher,
write_cipher );
/*
}else if ( selected_protocol == CRYPTO_AES ){
try{
SecretKeySpec secret_key_spec = new SecretKeySpec( secret_bytes, 32, AES_STREAM_KEY_SIZE_BYTES, AES_STREAM_ALG );
AlgorithmParameterSpec spec = new IvParameterSpec( secret_bytes, 48, AES_STREAM_KEY_SIZE_BYTES );
write_cipher = new TCPTransportCipher( AES_STREAM_CIPHER, Cipher.ENCRYPT_MODE, secret_key_spec, spec );
read_cipher = new TCPTransportCipher( AES_STREAM_CIPHER, Cipher.DECRYPT_MODE, secret_key_spec, spec );
filter = new TCPTransportHelperFilterStreamCipher(
helper,
read_cipher,
write_cipher );
}catch( Throwable e ){
throw( new IOException( "AES crypto init failed: " + Debug.getNestedExceptionMessage(e)));
}
*/
}else{
throw( new IOException( "Invalid selected protocol '" + selected_protocol + "'" ));
}
if ( initial_data_in != null ){
filter = new TransportHelperFilterInserter( filter, initial_data_in );
}
handshake_complete = true;
}
/*
X_1
A->B: Diffie Hellman Ya, PadA
X_2
B->A: Diffie Hellman Yb, PadB
X_3
A->B: HASH('req1', S), HASH('req2', SKEY)^HASH('req3', S), ENCRYPT(VC, crypto_provide, len(PadC), PadC, len(IA)), ENCRYPT(IA)
X_4
B->A: ENCRYPT(VC, crypto_select, len(padD), padD ) // , len(IB)), ENCRYPT(IB)
*/
protected void
process()
throws IOException
{
try{
process_mon.enter();
if ( handshake_complete ){
Debug.out( "Handshake process already completed" );
return;
}
boolean loop = true;
while( loop ){
// System.out.println( this + ":" + (outbound?"out: ":"in : ") + protocol_state + "/" + protocol_substate + ": r " + bytes_read + " - " + read_buffer + ", w " + bytes_written + " - " + write_buffer );
if ( protocol_state == PS_OUTBOUND_1 ){
if ( write_buffer == null ){
// A sends B Ya + Pa
byte[] padding_a = getRandomPadding(getPaddingMax()/2); // note that /2 also used in calculating max initial packet size above
write_buffer = ByteBuffer.allocate( dh_public_key_bytes.length + padding_a.length );
write_buffer.put( dh_public_key_bytes );
write_buffer.put( padding_a );
write_buffer.flip();
}
write( write_buffer );
if ( !write_buffer.hasRemaining()){
write_buffer = null;
protocol_state = PS_INBOUND_2;
}
}else if ( protocol_state == PS_INBOUND_1 ){
// B receives Ya
read( read_buffer );
if ( !read_buffer.hasRemaining()){
read_buffer.flip();
byte[] other_dh_public_key_bytes = new byte[read_buffer.remaining()];
read_buffer.get( other_dh_public_key_bytes );
completeDH( other_dh_public_key_bytes );
read_buffer = null;
protocol_state = PS_OUTBOUND_2;
}
}else if ( protocol_state == PS_OUTBOUND_2 ){
// B->A: Yb PadB
if ( write_buffer == null ){
byte[] padding_b = getRandomPadding( getPaddingMax()/2 );
write_buffer = ByteBuffer.allocate( dh_public_key_bytes.length + padding_b.length );
write_buffer.put( dh_public_key_bytes );
write_buffer.put( padding_b );
write_buffer.flip();
}
write( write_buffer );
if ( !write_buffer.hasRemaining()){
write_buffer = null;
protocol_state = PS_INBOUND_3;
}
}else if ( protocol_state == PS_INBOUND_2 ){
// A receives: Yb
if ( read_buffer == null ){
read_buffer = ByteBuffer.allocate( dh_public_key_bytes.length );
}
read( read_buffer );
if ( !read_buffer.hasRemaining()){
read_buffer.flip();
byte[] other_dh_public_key_bytes = new byte[read_buffer.remaining()];
read_buffer.get( other_dh_public_key_bytes );
completeDH( other_dh_public_key_bytes );
// A initiates SKEY so we can now set up crypto
setupCrypto();
read_buffer = null;
protocol_state = PS_OUTBOUND_3;
}
}else if ( protocol_state == PS_OUTBOUND_3 ){
// A->B: HASH('req1', S), HASH('req2', SKEY)^HASH('req3', S), ENCRYPT(VC, crypto_provide, len(PadC), PadC, len(IA)), ENCRYPT(IA)
if ( write_buffer == null ){
int initial_data_out_len = initial_data_out==null?0:initial_data_out.remaining();
// padding_a here is half of the padding from before
int pad_max = getPaddingMax();
byte[] padding_a = getRandomPadding(pad_max/2);
byte[] padding_c = getZeroPadding(pad_max);
write_buffer = ByteBuffer.allocate( padding_a.length + 20 + 20 + ( VC.length + 4 + 2 + padding_c.length + 2 ) + initial_data_out_len );
write_buffer.put( padding_a );
// HASH('req1', S)
SHA1Hasher hasher = new SHA1Hasher();
hasher.update( REQ1_IV );
hasher.update( secret_bytes );
byte[] sha1 = hasher.getDigest();
write_buffer.put( sha1 );
// HASH('req2', SKEY)^HASH('req3', S)
hasher = new SHA1Hasher();
hasher.update( REQ2_IV );
hasher.update( shared_secret );
byte[] sha1_1 = hasher.getDigest();
hasher = new SHA1Hasher();
hasher.update( REQ3_IV );
hasher.update( secret_bytes );
byte[] sha1_2 = hasher.getDigest();
for (int i=0;i<sha1_1.length;i++){
sha1_1[i] ^= sha1_2[i];
}
write_buffer.put( sha1_1 );
// ENCRYPT(VC, crypto_provide, len(PadC), PadC, len(IA)
write_buffer.put( write_cipher.update( VC ));
write_buffer.put( write_cipher.update( new byte[]{ 0, 0, 0, my_supported_protocols }));
write_buffer.put( write_cipher.update( new byte[]{ (byte)(padding_c.length>>8),(byte)padding_c.length }));
write_buffer.put( write_cipher.update( padding_c ));
write_buffer.put( write_cipher.update( new byte[]{ (byte)(initial_data_out_len>>8),(byte)initial_data_out_len }));
if ( initial_data_out_len > 0 ){
int save_pos = initial_data_out.position();
write_cipher.update( initial_data_out, write_buffer );
// reset in case buffer needs to be used again by caller
initial_data_out.position( save_pos );
initial_data_out = null;
}
write_buffer.flip();
}
write( write_buffer );
if ( !write_buffer.hasRemaining()){
write_buffer = null;
protocol_state = PS_INBOUND_4;
}
}else if ( protocol_state == PS_INBOUND_3 ){
// B receives: HASH('req1', S), HASH('req2', SKEY)^HASH('req3', S), ENCRYPT(VC, crypto_provide, len(PadC), PadC, len(IA)), ENCRYPT(IA)
if ( read_buffer == null ){
read_buffer = ByteBuffer.allocate( 20 + PADDING_MAX );
read_buffer.limit( 20 );
SHA1Hasher hasher = new SHA1Hasher();
hasher.update( REQ1_IV );
hasher.update( secret_bytes );
padding_skip_marker = hasher.getDigest();
protocol_substate = 1;
}
while( true ){
read( read_buffer );
if ( read_buffer.hasRemaining()){
break;
}
if ( protocol_substate == 1 ){
//skip up to HASH('req1', S)
int limit = read_buffer.limit();
read_buffer.position( limit - 20 );
boolean match = true;
for (int i=0;i<20;i++){
if ( read_buffer.get() != padding_skip_marker[i] ){
match = false;
break;
}
}
if ( match ){
read_buffer = ByteBuffer.allocate( 20 + VC.length + 4 + 2 );
protocol_substate = 2;
break;
}else{
if ( limit == read_buffer.capacity()){
throw( new IOException( "PHE skip to SHA1 marker failed" ));
}
read_buffer.limit( limit + 1 );
read_buffer.position( limit );
}
}else if ( protocol_substate == 2 ){
// find SKEY using HASH('req2', SKEY)^HASH('req3', S) , ENCRYPT(VC, crypto_provide, len(PadC),
read_buffer.flip();
final byte[] decode = new byte[20];
read_buffer.get( decode );
SHA1Hasher hasher = new SHA1Hasher();
hasher.update( REQ3_IV );
hasher.update( secret_bytes );
byte[] sha1 = hasher.getDigest();
for (int i=0;i<decode.length;i++){
decode[i] ^= sha1[i];
}
synchronized( global_shared_secrets ){
shared_secret = (byte[])global_shared_secrets.get( new HashWrapper( decode ));
}
if ( shared_secret == null ){
throw( new IOException( "No matching shared secret" ));
}
// System.out.println( "inbound - using crypto secret " + ByteFormatter.encodeString( shared_secret ));
setupCrypto();
byte[] crypted = new byte[VC.length + 4 + 2];
read_buffer.get( crypted );
byte[] plain = read_cipher.update( crypted );
byte other_supported_protocols = plain[VC.length+3];
int common_protocols = my_supported_protocols & other_supported_protocols;
if (( common_protocols & CRYPTO_PLAIN )!= 0 ){
selected_protocol = CRYPTO_PLAIN;
}else if (( common_protocols & CRYPTO_XOR )!= 0 ){
selected_protocol = CRYPTO_XOR;
}else if (( common_protocols & CRYPTO_RC4 )!= 0 ){
selected_protocol = CRYPTO_RC4;
}else if (( common_protocols & CRYPTO_AES )!= 0 ){
selected_protocol = CRYPTO_AES;
}else{
throw( new IOException(
"No crypto protocol in common: mine = " +
Integer.toHexString((byte)my_supported_protocols) + ", theirs = " +
Integer.toHexString((byte)other_supported_protocols)));
}
int padding = (( plain[VC.length+4] & 0xff ) << 8 ) + ( plain[VC.length+5] & 0xff );
if ( padding > PADDING_MAX ){
throw( new IOException( "Invalid padding '" + padding + "'" ));
}
read_buffer = ByteBuffer.allocate( padding + 2 );
// skip the padding
protocol_substate = 3;
}else if ( protocol_substate == 3 ){
// ENCRYPT( len(IA)), { ENCRYPT(IA) }
read_buffer.flip();
byte[] data = new byte[read_buffer.remaining()];
read_buffer.get( data );
data = read_cipher.update( data );
int ia_len = 0xffff & ((( data[data.length-2] & 0xff ) << 8 ) + ( data[data.length-1] & 0xff ));
if ( ia_len > 65535 ){
throw( new IOException( "Invalid IA length '" + ia_len + "'" ));
}
if ( ia_len > 0 ){
read_buffer = ByteBuffer.allocate( ia_len );
// skip the padding
protocol_substate = 4;
}else{
read_buffer = null;
protocol_state = PS_OUTBOUND_4;
break;
}
}else if ( protocol_substate == 4 ){
// ENCRYPT(IA)
read_buffer.flip();
byte[] data = new byte[read_buffer.remaining()];
read_buffer.get( data );
data = read_cipher.update( data );
// hack alert - we can delay the writing of the outbound_4 packet if this is an incoming packet with
// a piggybacked bt handshake as we know that we'll be sending our own handshake back out pretty soon
// and it'll take the delayed data with it. To be more generic we'd need to add a callback to the pattern
// matcher to allow it to decide whether delaying was sensible / or stick a timer on the delayed data
delay_outbound_4 = new String( data ).indexOf( "BitTorrent" ) != -1;
// System.out.println( "Initial Data In: " + new String( data ) + "->delay=" +delay_outbound_4 );
initial_data_in = ByteBuffer.wrap( data );
read_buffer = null;
protocol_state = PS_OUTBOUND_4;
break;
}
}
}else if ( protocol_state == PS_OUTBOUND_4 ){
// B->A: ENCRYPT(VC, crypto_select, len(padD), padD, // len(IB)), ENCRYPT(IB)
if ( write_buffer == null ){
int pad_max = getPaddingMax();
byte[] padding_b = getRandomPadding( pad_max/2 ); // half padding b sent here
byte[] padding_d = getZeroPadding( pad_max );
write_buffer = ByteBuffer.allocate( padding_b.length + VC.length + 4 + 2 + padding_d.length ); // + 2 + initial_data_out.length );
write_buffer.put( padding_b );
write_buffer.put( write_cipher.update( VC ));
write_buffer.put( write_cipher.update( new byte[]{ 0, 0, 0, selected_protocol }));
write_buffer.put( write_cipher.update( new byte[]{ (byte)(padding_d.length>>8),(byte)padding_d.length }));
write_buffer.put( write_cipher.update( padding_d ));
//write_buffer.put( write_cipher.update( new byte[]{ (byte)(initial_data_out.length>>8),(byte)initial_data_out.length }));
//write_buffer.put( write_cipher.update( initial_data_out ));
write_buffer.flip();
}
if ( delay_outbound_4 ){
if ( transport.delayWrite( write_buffer )){
write_buffer = null;
handshakeComplete();
}else{
delay_outbound_4 = false;
}
}
if ( !delay_outbound_4 ){
write( write_buffer );
if ( !write_buffer.hasRemaining()){
write_buffer = null;
handshakeComplete();
}
}
}else if ( protocol_state == PS_INBOUND_4 ){
// B->A: ENCRYPT(VC, crypto_select, len(padD), padD // , len(IB)), ENCRYPT(IB)
if ( read_buffer == null ){
read_buffer = ByteBuffer.allocate( VC.length + PADDING_MAX );
read_buffer.limit( VC.length );
padding_skip_marker = new byte[VC.length];
padding_skip_marker = read_cipher.update( padding_skip_marker );
protocol_substate = 1;
}
while( true ){
read( read_buffer );
if ( read_buffer.hasRemaining()){
break;
}
if ( protocol_substate == 1 ){
//skip up to marker
int limit = read_buffer.limit();
read_buffer.position( limit - VC.length );
boolean match = true;
for (int i=0;i<VC.length;i++){
if ( read_buffer.get() != padding_skip_marker[i] ){
match = false;
break;
}
}
if ( match ){
read_buffer = ByteBuffer.allocate( 4 + 2 );
protocol_substate = 2;
break;
}else{
if ( limit == read_buffer.capacity()){
throw( new IOException( "PHE skip to SHA1 marker failed" ));
}
read_buffer.limit( limit + 1 );
read_buffer.position( limit );
}
}else if ( protocol_substate == 2 ){
// ENCRYPT( crypto_select, len(padD))
read_buffer.flip();
byte[] crypted = new byte[4 + 2];
read_buffer.get( crypted );
byte[] plain = read_cipher.update( crypted );
selected_protocol = plain[3];
if (( selected_protocol & my_supported_protocols ) == 0 ){
throw( new IOException(
"Selected protocol has nothing in common: mine = " +
Integer.toHexString((byte)my_supported_protocols) + ", theirs = " +
Integer.toHexString((byte)selected_protocol)));
}
int pad_len = 0xffff&((( plain[4] & 0xff ) << 8 ) + ( plain[5] & 0xff ));
if ( pad_len > 65535 ){
throw( new IOException( "Invalid pad length '" + pad_len + "'" ));
}
read_buffer = ByteBuffer.allocate( pad_len ); // + 2 );
protocol_substate = 3;
}else if ( protocol_substate == 3 ){
read_buffer.flip();
byte[] data = new byte[read_buffer.remaining()];
read_buffer.get( data );
data = read_cipher.update( data );
handshakeComplete();
read_buffer = null;
break;
/*
int ib_len = 0xffff & ((( data[data.length-2] & 0xff ) << 8 ) + ( data[data.length-1] & 0xff ));
if ( ib_len > 65535 ){
throw( new IOException( "Invalid IB length '" + ib_len + "'" ));
}
read_buffer = ByteBuffer.allocate( ib_len );
protocol_substate = 4;
}else{
read_buffer.flip();
byte[] data = new byte[read_buffer.remaining()];
read_buffer.get( data );
initial_data_in = read_cipher.update( data );
handshakeComplete();
read_buffer = null;
break;
*/
}
}
}
if ( handshake_complete ){
transport.cancelReadSelects();
transport.cancelWriteSelects();
loop = false;
complete();
}else{
if ( read_buffer == null ){
transport.pauseReadSelects();
}else{
transport.resumeReadSelects();
loop = false;
}
if ( write_buffer == null ){
transport.pauseWriteSelects();
}else{
transport.resumeWriteSelects();
loop = false;
}
}
}
}catch( Throwable e ){
failed( e );
if ( e instanceof IOException ){
throw((IOException)e);
}else{
throw( new IOException( Debug.getNestedExceptionMessage(e)));
}
}finally{
process_mon.exit();
}
}
/*
**** OUTBOUND_1
A sends B odd/even byte + Ya + Pa
**** INBOUND_1
B receives Ya
B computes Yb
B computes S and HS
**** OUTBOUND_2
B sends A Yb + HS( "supported methods" + len(Pb)) + Pb
**** INBOUND_2
A receives Yb
A computes S and HS
A receives HS( "supported methods" + len(Pb)) and decrypts using HS
A skips len(Pb) random bytes
**** OUTBOUND_3
A sends SHA1(S) + HS( "selected method" + len(Pc)) + Pc + selectedCrypt( payload )
**** INBOUND_3
B skips Pa bytes until receives SHA1(S)
B decrypts "selected method" + len(Pc) and skips len(Pc) bytes to get to selectedCrypt( payload... )
B sends A selectedCrypt( payload... )
*/
/*
protected void
process()
throws IOException
{
try{
process_mon.enter();
if ( handshake_complete ){
Debug.out( "Handshake process already completed" );
return;
}
boolean loop = true;
while( loop ){
if ( protocol_state == PS_OUTBOUND_1 ){
if ( write_buffer == null ){
// A sends B odd/even Ya + Pa
byte[] padding = getPadding();
write_buffer = ByteBuffer.allocate( dh_public_key_bytes.length + padding.length );
write_buffer.put( dh_public_key_bytes );
write_buffer.put( padding );
write_buffer.flip();
}
write( write_buffer );
if ( !write_buffer.hasRemaining()){
write_buffer = null;
protocol_state = PS_INBOUND_2;
}
}else if ( protocol_state == PS_OUTBOUND_2 ){
// B sends A Yb + HS( "supported methods" + len(Pb)) + Pb
if ( write_buffer == null ){
byte[] padding = getPadding();
write_buffer = ByteBuffer.allocate( dh_public_key_bytes.length + 4 + 2 + padding.length );
write_buffer.put( dh_public_key_bytes );
// 4 bytes for my supported protocols
write_buffer.put( write_cipher.update( new byte[]{ 0, 0, 0, my_supported_protocols }));
write_buffer.put( write_cipher.update( new byte[]{ (byte)(padding.length>>8),(byte)padding.length }));
write_buffer.put( padding );
write_buffer.flip();
}
write( write_buffer );
if ( !write_buffer.hasRemaining()){
write_buffer = null;
protocol_state = PS_INBOUND_3;
}
}else if ( protocol_state == PS_OUTBOUND_3 ){
// A sends SHA1(S) + HS( "selected method" + len(Pc)) + Pc + selectedCrypt( payload )
if ( write_buffer == null ){
byte[] padding = getPadding();
write_buffer = ByteBuffer.allocate( 20 + 4 + 2 + padding.length );
write_buffer.put( sha1_secret_bytes );
write_buffer.put( write_cipher.update( new byte[]{ 0, 0, 0, selected_protocol }));
write_buffer.put( write_cipher.update( new byte[]{ (byte)(padding.length>>8),(byte)padding.length }));
write_buffer.put( padding );
write_buffer.flip();
}
write( write_buffer );
if ( !write_buffer.hasRemaining()){
write_buffer = null;
handshakeComplete();
}
}else if ( protocol_state == PS_INBOUND_1 ){
// B receives marker + Ya
read( read_buffer );
if ( !read_buffer.hasRemaining()){
read_buffer.flip();
byte[] other_dh_public_key_bytes = new byte[read_buffer.remaining()];
read_buffer.get( other_dh_public_key_bytes );
completeDH( other_dh_public_key_bytes );
read_buffer = null;
protocol_state = PS_OUTBOUND_2;
}
}else if ( protocol_state == PS_INBOUND_2 ){
//A receives Yb
//A computes S and HS
//A receives HS( "supported methods" + len(Pb)) and decrypts using HS
//A skips len(Pb) random bytes
if ( read_buffer == null ){
read_buffer = ByteBuffer.allocate( dh_public_key_bytes.length + 6 );
protocol_substate = 1;
}
while( true ){
read( read_buffer );
if ( read_buffer.hasRemaining()){
break;
}
if ( protocol_substate == 1 ){
read_buffer.flip();
byte[] other_dh_public_key_bytes_etc = read_buffer.array();
completeDH( other_dh_public_key_bytes_etc );
byte[] etc = read_cipher.update( other_dh_public_key_bytes_etc, DH_SIZE_BYTES, 6 );
byte other_supported_protocols = etc[3];
int common_protocols = my_supported_protocols & other_supported_protocols;
if (( common_protocols & CRYPTO_PLAIN )!= 0 ){
selected_protocol = CRYPTO_PLAIN;
}else if (( common_protocols & CRYPTO_XOR )!= 0 ){
selected_protocol = CRYPTO_XOR;
}else if (( common_protocols & CRYPTO_RC4 )!= 0 ){
selected_protocol = CRYPTO_RC4;
}else if (( common_protocols & CRYPTO_AES )!= 0 ){
selected_protocol = CRYPTO_AES;
}else{
throw( new IOException(
"No crypto protocol in common: mine = " +
Integer.toHexString((byte)my_supported_protocols) + ", theirs = " +
Integer.toHexString((byte)other_supported_protocols)));
}
int padding = (( etc[4] & 0xff ) << 8 ) + ( etc[5] & 0xff );
if ( padding > PADDING_MAX ){
throw( new IOException( "Invalid padding '" + padding + "'" ));
}
read_buffer = ByteBuffer.allocate( padding );
protocol_substate = 2;
}else{
read_buffer = null;
protocol_state = PS_OUTBOUND_3;
break;
}
}
}else if ( protocol_state == PS_INBOUND_3 ){
// B skips Pa bytes until receives SHA1(S)
// B decrypts "selected method" + len(Pc) and skips len(Pc) bytes
if ( read_buffer == null ){
read_buffer = ByteBuffer.allocate( 20 + PADDING_MAX );
read_buffer.limit( 20 );
protocol_substate = 1;
}
while( true ){
read( read_buffer );
if ( read_buffer.hasRemaining()){
break;
}
if ( protocol_substate == 1 ){
int limit = read_buffer.limit();
read_buffer.position( limit - 20 );
boolean match = true;
for (int i=0;i<20;i++){
if ( read_buffer.get() != sha1_secret_bytes[i] ){
match = false;
break;
}
}
if ( match ){
read_buffer = ByteBuffer.allocate( 6 );
protocol_substate = 2;
break;
}else{
if ( limit == read_buffer.capacity()){
throw( new IOException( "PHE skip to SHA1 marker failed" ));
}
read_buffer.limit( limit + 1 );
read_buffer.position( limit );
}
}else if ( protocol_substate == 2 ){
read_buffer.flip();
byte[] etc = read_cipher.update( read_buffer.array());
selected_protocol = etc[3];
int padding = (( etc[4] & 0xff ) << 8 ) + ( etc[5] & 0xff );
if ( padding > PADDING_MAX ){
throw( new IOException( "Invalid padding '" + padding + "'" ));
}
read_buffer = ByteBuffer.allocate( padding );
protocol_substate = 3;
}else{
read_buffer = null;
handshakeComplete();
break;
}
}
}
if ( handshake_complete ){
read_selector.cancel( channel );
write_selector.cancel( channel );
loop = false;
complete();
}else{
if ( read_buffer == null ){
read_selector.pauseSelects( channel );
}else{
read_selector.resumeSelects ( channel );
loop = false;
}
if ( write_buffer == null ){
write_selector.pauseSelects( channel );
}else{
write_selector.resumeSelects ( channel );
loop = false;
}
}
}
}catch( Throwable e ){
failed( e );
if ( e instanceof IOException ){
throw((IOException)e);
}else{
throw( new IOException( Debug.getNestedExceptionMessage(e)));
}
}finally{
process_mon.exit();
}
}
*/
protected void
read(
ByteBuffer buffer )
throws IOException
{
int len = transport.read( buffer );
//System.out.println( "read:" + this + "/" + protocol_state + "/" + protocol_substate + " -> " + len +"[" + buffer +"]");
if ( len < 0 ){
throw( new IOException( "end of stream on socket read - phe: " + getString()));
}
bytes_read += len;
}
protected void
write(
ByteBuffer buffer )
throws IOException
{
//System.out.println( "write pre:" + this + "/" + protocol_state + "/" + protocol_substate + " - " + buffer );
int len = transport.write( buffer, false );
//System.out.println( "write:" + this + "/" + protocol_state + "/" + protocol_substate + " -> " + len +"[" + buffer +"]");
if ( len < 0 ){
throw( new IOException( "bytes written < 0 " ));
}
bytes_written += len;
}
public boolean
selectSuccess(
TransportHelper transport,
Object attachment,
boolean write_operation )
{
try{
int old_bytes_read = bytes_read;
int old_bytes_written = bytes_written;
process();
if ( write_operation ){
return( bytes_written != old_bytes_written );
}else{
boolean progress = bytes_read != old_bytes_read;
if ( progress ){
last_read_time = SystemTime.getCurrentTime();
}
return( progress );
}
}catch( Throwable e ){
failed( e );
return( false );
}
}
public void
selectFailure(
TransportHelper transport,
Object attachment,
Throwable msg )
{
failed( msg );
}
protected byte[]
bigIntegerToBytes(
BigInteger bi,
int num_bytes )
{
String str = bi.toString(16);
while( str.length() < num_bytes*2 ){
str = "0" + str;
}
return( ByteFormatter.decodeString(str));
}
protected BigInteger
bytesToBigInteger(
byte[] bytes,
int offset,
int len )
{
return( new BigInteger( ByteFormatter.encodeString( bytes, offset, len ), 16 ));
}
protected int
getPaddingMax()
{
if ( transport.minimiseOverheads()){
return( PADDING_MAX_LIMITED );
}else{
return( PADDING_MAX_NORMAL );
}
}
protected static synchronized byte[]
getRandomPadding(
int max_len )
{
byte[] bytes = new byte[ random.nextInt(max_len)];
random.nextBytes(bytes);
return( bytes );
}
protected static synchronized byte[]
getZeroPadding(
int max_len )
{
byte[] bytes = new byte[ random.nextInt(max_len)];
return( bytes );
}
protected static KeyPair
generateDHKeyPair(
TransportHelper transport,
boolean outbound )
throws IOException
{
if ( dh_key_generator == null ){
throw( new IOException( "Crypto not setup" ));
}
synchronized( dh_key_generator ){
if ( !outbound ){
InetSocketAddress is_address = transport.getAddress();
byte[] address = AddressUtils.getAddressBytes( is_address );
int hit_count = generate_bloom.add( address );
long now = SystemTime.getCurrentTime();
// allow up to 10% bloom filter utilisation
if ( generate_bloom.getSize() / generate_bloom.getEntryCount() < 10 ){
generate_bloom = BloomFilterFactory.createAddRemove4Bit(generate_bloom.getSize() + BLOOM_INCREASE );
generate_bloom_create_time = now;
Logger.log( new LogEvent(LOGID, "PHE bloom: size increased to " + generate_bloom.getSize()));
}else if ( now < generate_bloom_create_time || now - generate_bloom_create_time > BLOOM_RECREATE ){
generate_bloom = BloomFilterFactory.createAddRemove4Bit(generate_bloom.getSize());
generate_bloom_create_time = now;
}
if ( hit_count >= 15 ){
Logger.log( new LogEvent(LOGID, "PHE bloom: too many recent connection attempts from " + transport.getAddress()));
throw( new IOException( "Too many recent connection attempts (phe)"));
}
long since_last = now - last_dh_incoming_key_generate;
long delay = 100 - since_last;
// limit key gen operations to 10 a second
if ( delay > 0 && delay < 100 ){
try{
Thread.sleep( delay );
}catch( Throwable e ){
}
}
last_dh_incoming_key_generate = now;
}
KeyPair res = dh_key_generator.generateKeyPair();
return( res );
}
}
protected void
complete()
{
// System.out.println( (outbound?"out: ":"in :") + " complete, r " + bytes_read + ", w " + bytes_written + ", initial data = " + initial_data_in.length + "/" + initial_data_out.length );
processing_complete = true;
transport.setScatteringMode(0);
adapter.decodeComplete( this, initial_data_out );
}
protected void
failed(
Throwable cause )
{
// System.out.println( (outbound?"out: ":"in :") + " failed, " + cause.getMessage());
processing_complete = true;
transport.cancelReadSelects();
transport.cancelWriteSelects();
adapter.decodeFailed( this, cause );
}
public boolean
isComplete(
long now )
{
return( processing_complete );
}
public TransportHelperFilter
getFilter()
{
return( filter );
}
public long
getLastReadTime()
{
long now = SystemTime.getCurrentTime();
if ( last_read_time > now ){
last_read_time = now;
}
return( last_read_time );
}
public String
getString()
{
return( "state=" + protocol_state + ",sub=" + protocol_substate + ",in=" + bytes_read + ",out=" + bytes_written);
}
}