Binding CXF Client source IP address

Question

I have a CXF client that connects to a Web Service. This client is installed in a machine tha has two IP addresses in the same network (for example 172.16.1.101 and 172.16.1.102).

How can I configure the CXF client to use a specific source IP address, so that the server sees the requests coming from that specific IP address and not the other?

If I had access to the Socket, I would do something like:

Socket s = new Socket(); 
s.bind(new InetSocketAddress("172.16.1.102", 0));  //this Ip address is the one I need to specify
s.connect(new InetSocketAddress("google.com", 80));

Is it possible to configure the Sockets created by CXF so I can specify the source IP address?

EDIT: I need to specify the source IP address because between the client and the web server there is a firewall that has rules for one of the IP addresses (connections coming from the other IP address are blocked).

Answer 1

CXF client uses java.net.URLConnection to connect to a service. The URLConnection can be configured to select a local IP address in this way (see How can I specify the local address on a java.net.URLConnection?)

URL url = new URL(yourUrlHere);
Proxy proxy = new Proxy(Proxy.Type.DIRECT, 
    new InetSocketAddress( 
        InetAddress.getByAddress(
            new byte[]{your, ip, interface, here}), yourTcpPortHere));
URLConnection conn = url.openConnection(proxy);

I have inspected the code of artifacts cxf-rt-rs-client and cxf-rt-transports-http to see how CXF is creating the connection. In ProxyFactory is the code to create the Proxy object needed for the UrlConnection

private Proxy createProxy(final HTTPClientPolicy policy) {
    return new Proxy(Proxy.Type.valueOf(policy.getProxyServerType().toString()),
                     new InetSocketAddress(policy.getProxyServer(),
                                           policy.getProxyServerPort()));
}

As you can see, there is no way to configure the IP address, so i am afraid that the answer to the question is you can not configure source IP address with CXF

But, I think it would not be difficult to modify the source code to allow setting the source IP address

HTTPClientPolicy

Add the following code to org.apache.cxf.transports.http.configuration.HTTPClientPolicy at cxf-rt-transports-http

public class HTTPClientPolicy {
    protected byte[] sourceIPAddress;
    protected int port;

    public boolean isSetSourceIPAddress(){
        return (this.sourceIPAddress != null);
    }

ProxyFactory

Modify the following code to org.apache.cxf.transport.http.ProxyFactory at cxf-rt-transports-http

 //added || policy.isSetSourceIPAddress()
 //getProxy() calls finally to createProxy
 public Proxy createProxy(HTTPClientPolicy policy, URI currentUrl) {
    if (policy != null) {
        // Maybe the user has provided some proxy information
        if (policy.isSetProxyServer() || policy.isSetSourceIPAddress())
            && !StringUtils.isEmpty(policy.getProxyServer())) {
            return getProxy(policy, currentUrl.getHost());
        } else {
            // There is a policy but no Proxy configuration,
            // fallback on the system proxy configuration
            return getSystemProxy(currentUrl.getHost());
        }
    } else {
        // Use system proxy configuration
        return getSystemProxy(currentUrl.getHost());
    }
}

//Added condition to set the source IP address (is set)
//Will work also with a proxy
private Proxy createProxy(final HTTPClientPolicy policy) {
    if (policy.isSetSourceIPAddress()){
        Proxy proxy = new Proxy(Proxy.Type.DIRECT, 
            new InetSocketAddress( 
                InetAddress.getByAddress(
                    policy.getSourceIPAddress(), policy.getPort()));
    } else {
        return new Proxy(Proxy.Type.valueOf(policy.getProxyServerType().toString()),
                     new InetSocketAddress(policy.getProxyServer(),
                                           policy.getProxyServerPort()));
    }                
}

Usage

Client client = ClientProxy.getClient(service);
HTTPConduit http = (HTTPConduit) client.getConduit();
HTTPClientPolicy httpClientPolicy = new HTTPClientPolicy();
httpClientPolicy.setSourceIPAddress(new byte[]{your, ip, interface, here}));
httpClientPolicy.setPort(yourTcpPortHere);
http.setClient(httpClientPolicy);

Answer 2

A custom URLStreamHandlerFactory works.

Example:

        ...
        URL.setURLStreamHandlerFactory(new URLStreamHandlerFactory() {
            @Override
            public URLStreamHandler createURLStreamHandler(String protocol) {
                if (protocol.equals("http")) {
                    return new HttpHandler();
                } else if (protocol.equals("https")) {
                    return new sun.net.www.protocol.https.Handler();
                }
                return null;
            }
        });
        ...

private class HttpHandler extends java.net.URLStreamHandler {

    protected int getDefaultPort() {
        return 80;
    }

    @Override
    protected URLConnection openConnection(URL u) throws IOException {
        return openConnection(u, (Proxy) null);
    }

    @Override
    protected URLConnection openConnection(URL u, Proxy p) throws IOException {
        return new HttpURLConnection(u, p) {

            @Override
            protected HttpClient getNewHttpClient(URL url, Proxy p, int connectTimeout)
                    throws IOException {
                return new HttpClient(url, (String) null, -1, true, connectTimeout) {

                    @Override
                    protected Socket createSocket() throws IOException {
                        Socket s = new Socket();

                        s.bind(new InetSocketAddress(InetAddress.getByName("1.2.3.4"),
                                0)); // yours IP here

                        return s;
                    }

                };
            }

            @Override
            protected HttpClient getNewHttpClient(URL url, Proxy p, int connectTimeout,
                    boolean useCache) throws IOException {
                return getNewHttpClient(url, p, connectTimeout);
            }

        };
    }
}

For HTTPS also usable a custom SSLSocketFactory

HttpsURLConnection.setDefaultSSLSocketFactory(...);