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Add support for specifying IP version #332

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88 changes: 80 additions & 8 deletions src/main/java/com/trilead/ssh2/Connection.java
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Original file line number Diff line number Diff line change
Expand Up @@ -46,6 +46,16 @@

public class Connection implements AutoCloseable
{
/**
* Allow the caller to restrict the IP version of the connection to
* be established.
*/
public enum IpVersion {
IPV4_AND_IPV6, ///< Allow both IPV4 and IPv6, the default.
IPV4_ONLY, ///< Require that the connection be over IPv4 only.
IPV6_ONLY ///< Require that the connection be over IPv6 only.
}

/**
* The identifier presented to the SSH-2 server.
*/
Expand Down Expand Up @@ -564,30 +574,74 @@ private void close(Throwable t, boolean hard)

/**
* Same as
* {@link #connect(ServerHostKeyVerifier, int, int) connect(null, 0, 0)}.
* {@link #connect(ServerHostKeyVerifier, int, int, IpVersion) connect(null, 0, 0, IpVersion.IPV4_AND_IPV6)}.
*
* @return see comments for the
* {@link #connect(ServerHostKeyVerifier, int, int) connect(ServerHostKeyVerifier, int, int)}
* {@link #connect(ServerHostKeyVerifier, int, int, IpVersion) connect(ServerHostKeyVerifier, int, int, IpVersion)}
* method.
* @throws IOException
*/
public synchronized ConnectionInfo connect() throws IOException
{
return connect(null, 0, 0);
return connect(null, 0, 0, IpVersion.IPV4_AND_IPV6);
}

/**
* Same as
* {@link #connect(ServerHostKeyVerifier, int, int, IpVersion) connect(null, 0, 0, ipVersion)}.
*
* @return see comments for the
* {@link #connect(ServerHostKeyVerifier, int, int, IpVersion) connect(ServerHostKeyVerifier, int, int, IpVersion)}
* method.
* @throws IOException
*/
public synchronized ConnectionInfo connect(IpVersion ipVersion) throws IOException
{
return connect(null, 0, 0, ipVersion);
}


/**
* Same as
* {@link #connect(ServerHostKeyVerifier, int, int) connect(verifier, 0, 0)}.
* {@link #connect(ServerHostKeyVerifier, int, int, IpVersion) connect(verifier, 0, 0, IpVersion.IPV4_AND_IPV6)}.
*
* @return see comments for the
* {@link #connect(ServerHostKeyVerifier, int, int) connect(ServerHostKeyVerifier, int, int)}
* {@link #connect(ServerHostKeyVerifier, int, int, IpVersion) connect(ServerHostKeyVerifier, int, int, IpVersion)}
* method.
* @throws IOException
*/
public synchronized ConnectionInfo connect(ServerHostKeyVerifier verifier) throws IOException
{
return connect(verifier, 0, 0);
return connect(verifier, 0, 0, IpVersion.IPV4_AND_IPV6);
}

/**
* Same as
* {@link #connect(ServerHostKeyVerifier, int, int, IpVersion) connect(verifier, 0, 0, ipVersion)}.
*
* @return see comments for the
* {@link #connect(ServerHostKeyVerifier, int, int, IpVersion) connect(ServerHostKeyVerifier, int, int, IpVersion)}
* method.
* @throws IOException
*/
public synchronized ConnectionInfo connect(ServerHostKeyVerifier verifier, IpVersion ipVersion) throws IOException
{
return connect(verifier, 0, 0, ipVersion);
}

/**
* Same as
* {@link #connect(ServerHostKeyVerifier, int, int, IpVersion) connect(verifier, connectTimeout, kexTimeout, IpVersion.IPV4_AND_IPV6)}.
*
* @return see comments for the
* {@link #connect(ServerHostKeyVerifier, int, int, IpVersion) connect(ServerHostKeyVerifier, int, int, IpVersion)}
* method.
* @throws IOException
*/
public synchronized ConnectionInfo connect(ServerHostKeyVerifier verifier, int connectTimeout, int kexTimeout)
throws IOException
{
return connect(verifier, connectTimeout, kexTimeout, IpVersion.IPV4_AND_IPV6);
}

/**
Expand Down Expand Up @@ -649,6 +703,11 @@ public synchronized ConnectionInfo connect(ServerHostKeyVerifier verifier) throw
* but it will only have an effect after the
* <code>verifier</code> returns.
*
* @param ipVersion
* Specify whether the connection should be restricted to one of
* IPv4 or IPv6, with a default of allowing both. See
* {@link IpVersion}.
*
* @return A {@link ConnectionInfo} object containing the details of the
* established connection.
*
Expand All @@ -672,7 +731,7 @@ public synchronized ConnectionInfo connect(ServerHostKeyVerifier verifier) throw
* proxy is buggy and does not return a proper HTTP response,
* then a normal IOException is thrown instead.
*/
public synchronized ConnectionInfo connect(ServerHostKeyVerifier verifier, int connectTimeout, int kexTimeout)
public synchronized ConnectionInfo connect(ServerHostKeyVerifier verifier, int connectTimeout, int kexTimeout, IpVersion ipVersion)
throws IOException
{
final class TimeoutState
Expand Down Expand Up @@ -745,9 +804,22 @@ public void run()
token = TimeoutService.addTimeoutHandler(timeoutHorizont, timeoutHandler);
}

TransportManager.IpVersion tmIpVersion;
if (ipVersion == IpVersion.IPV4_ONLY)
{
tmIpVersion = TransportManager.IpVersion.IPV4_ONLY;
}
else if (ipVersion == IpVersion.IPV6_ONLY) {
tmIpVersion = TransportManager.IpVersion.IPV6_ONLY;
}
else // Assume (ipVersion == IpVersion.IPV4_AND_IPV6), the default.
{
tmIpVersion = TransportManager.IpVersion.IPV4_AND_IPV6;
}

try
{
tm.initialize(cryptoWishList, verifier, dhgexpara, connectTimeout, getOrCreateSecureRND(), proxyData);
tm.initialize(cryptoWishList, verifier, dhgexpara, connectTimeout, tmIpVersion, getOrCreateSecureRND(), proxyData);
}
catch (SocketTimeoutException se)
{
Expand Down
52 changes: 46 additions & 6 deletions src/main/java/com/trilead/ssh2/transport/TransportManager.java
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,7 @@
import com.trilead.ssh2.ExtensionInfo;
import com.trilead.ssh2.packets.PacketExtInfo;
import java.io.IOException;
import java.net.Inet6Address;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import java.net.Socket;
Expand Down Expand Up @@ -49,6 +50,16 @@
*/
public class TransportManager
{
/**
* Allow the caller to restrict the IP version of the connection to
* be established.
*/
public enum IpVersion {
IPV4_AND_IPV6, ///< Allow both IPV4 and IPv6, the default.
IPV4_ONLY, ///< Require that the connection be over IPv4 only.
IPV6_ONLY ///< Require that the connection be over IPv6 only.
}

private static final Logger log = Logger.getLogger(TransportManager.class);

class HandlerEntry
Expand Down Expand Up @@ -265,30 +276,59 @@ public void close(Throwable cause, boolean useDisconnectPacket)
}
}

private void establishConnection(ProxyData proxyData, int connectTimeout) throws IOException
private static InetAddress getIPv4Address(InetAddress[] addresses) {
for (InetAddress address : addresses) {
if (! (address instanceof Inet6Address)) {
return address;
}
}
return null;
}
private static Inet6Address getIPv6Address(InetAddress[] addresses) {
for (InetAddress address : addresses) {
if (address instanceof Inet6Address) {
return (Inet6Address) address;
}
}
return null;
}

private void establishConnection(ProxyData proxyData, int connectTimeout, IpVersion ipVersion) throws IOException
{
if (proxyData == null)
sock = connectDirect(hostname, port, connectTimeout);
sock = connectDirect(hostname, port, connectTimeout, ipVersion);
else
sock = proxyData.openConnection(hostname, port, connectTimeout);
}

private static Socket connectDirect(String hostname, int port, int connectTimeout)
private static Socket connectDirect(String hostname, int port, int connectTimeout, IpVersion ipVersion)
throws IOException
{
Socket sock = new Socket();
InetAddress addr = InetAddress.getByName(hostname);
InetAddress addr;
if (ipVersion == IpVersion.IPV4_ONLY)
{
addr = getIPv4Address(InetAddress.getAllByName(hostname));
}
else if (ipVersion == IpVersion.IPV6_ONLY)
{
addr = getIPv6Address(InetAddress.getAllByName(hostname));
}
else // Assume (ipVersion == IpVersion.IPV4_AND_IPV6), the default.
{
addr = InetAddress.getByName(hostname);
}
sock.connect(new InetSocketAddress(addr, port), connectTimeout);
sock.setSoTimeout(0);
return sock;
}

public void initialize(CryptoWishList cwl, ServerHostKeyVerifier verifier, DHGexParameters dhgex,
int connectTimeout, SecureRandom rnd, ProxyData proxyData) throws IOException
int connectTimeout, IpVersion ipVersion, SecureRandom rnd, ProxyData proxyData) throws IOException
{
/* First, establish the TCP connection to the SSH-2 server */

establishConnection(proxyData, connectTimeout);
establishConnection(proxyData, connectTimeout, ipVersion);

/* Parse the server line and say hello - important: this information is later needed for the
* key exchange (to stop man-in-the-middle attacks) - that is why we wrap it into an object
Expand Down
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