Package org.littleshoot.proxy.impl

Class ProxyToServerConnection

java.lang.Object

io.netty.channel.ChannelHandlerAdapter

io.netty.channel.ChannelInboundHandlerAdapter

io.netty.channel.SimpleChannelInboundHandler<Object>

org.littleshoot.proxy.impl.ProxyConnection<HttpResponse>

org.littleshoot.proxy.impl.ProxyToServerConnection

All Implemented Interfaces:

ChannelHandler, ChannelInboundHandler

@Sharable
public class ProxyToServerConnection
extends ProxyConnection<HttpResponse>

Represents a connection from our proxy to a server on the web. ProxyConnections are reused fairly liberally, and can go from disconnected to connected, back to disconnected and so on.

Connecting a ProxyToServerConnection can involve more than just connecting the underlying Channel. In particular, the connection may use encryption (i.e. TLS) and it may also establish an HTTP CONNECT tunnel. The various steps involved in fully establishing a connection are encapsulated in the property connectionFlow, which is initialized in initializeConnectionFlow().

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
private class	ProxyToServerConnection.HeadAwareHttpResponseDecoder	Responses to HEAD requests aren't supposed to have content, but Netty doesn't know that any given response is to a HEAD request, so it needs to be told that there's no content so that it doesn't hang waiting for it.

Nested classes/interfaces inherited from class org.littleshoot.proxy.impl.ProxyConnection

ProxyConnection.BytesReadMonitor, ProxyConnection.BytesWrittenMonitor, ProxyConnection.RequestReadMonitor, ProxyConnection.RequestWrittenMonitor, ProxyConnection.ResponseReadMonitor, ProxyConnection.ResponseWrittenMonitor

Nested classes/interfaces inherited from interface io.netty.channel.ChannelHandler

ChannelHandler.Sharable

Field Summary

Fields

Modifier and Type	Field	Description
private final Queue<ChainedProxy>	availableChainedProxies
private final ProxyConnection<HttpResponse>.BytesReadMonitor	bytesReadMonitor
private final ProxyConnection<HttpResponse>.BytesWrittenMonitor	bytesWrittenMonitor
private ChainedProxy	chainedProxy
private ChainedProxyType	chainedProxyType
private final ClientToProxyConnection	clientConnection
private final ConnectionFlowStep	ConnectChannel	Opens the socket connection.
private ConnectionFlow	connectionFlow	Encapsulates the flow for establishing a connection, which can vary depending on how things are configured.
private final Object	connectLock	While we're in the process of connecting, it's possible that we'll receive a new message to write.
private HttpFilters	currentFilters	The filters to apply to response/chunks received from server.
private HttpRequest	currentHttpRequest	Keeps track of HttpRequests that have been issued so that we can associate them with responses that we get back
private HttpResponse	currentHttpResponse	While we're doing a chunked transfer, this keeps track of the initial HttpResponse object for our transfer (which is useful for its headers).
private boolean	disableSni	Disables SNI when initializing connection flow in initializeConnectionFlow().
private static final String	HTTP_DECODER_NAME
private static final String	HTTP_ENCODER_NAME
private static final String	HTTP_PROXY_ENCODER_NAME
private static final String	HTTP_REQUEST_WRITTEN_MONITOR_NAME
private static final String	HTTP_RESPONSE_READ_MONITOR_NAME
private final ConnectionFlowStep	HTTPCONNECTWithChainedProxy	Writes the HTTP CONNECT to the server and waits for a 200 response.
private HttpRequest	initialRequest	This is the initial request received prior to connecting.
private InetSocketAddress	localAddress
private static final String	MAIN_HANDLER_NAME
private static final int	MINIMUM_RECV_BUFFER_SIZE_BYTES	Minimum size of the adaptive recv buffer when throttling is enabled.
private final ConnectionFlowStep	MitmEncryptClientChannel	Encrypts the client channel based on our server SSLSession.
private String	password
private InetSocketAddress	remoteAddress
private io.netty.resolver.AddressResolverGroup<?>	remoteAddressResolver
private final ProxyConnection.RequestWrittenMonitor	requestWrittenMonitor
private final ProxyConnection<HttpResponse>.ResponseReadMonitor	responseReadMonitor
private final ProxyToServerConnection	serverConnection
private final String	serverHostAndPort
private static final String	SOCKS_DECODER_NAME
private static final String	SOCKS_ENCODER_NAME
private final ConnectionFlowStep	SOCKS4CONNECTWithChainedProxy	Establishes a SOCKS4 connection.
private final ConnectionFlowStep	SOCKS5CONNECTRequestWithChainedProxy	Establishes a SOCKS5 connection after SOCKS5InitialRequest and (optionally) SOCKS5SendPasswordCredentials have completed.
private final ConnectionFlowStep	SOCKS5InitialRequest	Initiates a SOCKS5 connection.
private final ConnectionFlowStep	SOCKS5SendPasswordCredentials	Sends SOCKS5 password credentials after SOCKS5InitialRequest has completed.
private final GlobalTrafficShapingHandler	trafficHandler	Limits bandwidth when throttling is enabled.
private TransportProtocol	transportProtocol
private String	username

Fields inherited from class org.littleshoot.proxy.impl.ProxyConnection

channel, ctx, lastReadTime, LOG, proxyServer, runsAsSslClient, sslEngine, StartTunneling, tunneling

Constructor Summary

Constructors

Modifier	Constructor	Description
private	ProxyToServerConnection(DefaultHttpProxyServer proxyServer, ClientToProxyConnection clientConnection, String serverHostAndPort, ChainedProxy chainedProxy, Queue<ChainedProxy> availableChainedProxies, HttpFilters initialFilters, GlobalTrafficShapingHandler globalTrafficShapingHandler)

Method Summary

Modifier and Type	Method	Description
private void	addFirstOrReplaceHandler(String name, ChannelHandler handler)
static InetSocketAddress	addressFor(String hostAndPort, DefaultHttpProxyServer proxyServer)	Build an InetSocketAddress for the given hostAndPort.
protected void	becameSaturated()	Callback that's invoked if this connection becomes saturated.
protected void	becameWritable()	Callback that's invoked when this connection becomes writeable again.
protected void	become(ConnectionState newState)	Updates the current state to the given value.
private void	connectAndWrite(HttpRequest initialRequest)	Configures the connection to the upstream server and begins the ConnectionFlow.
protected boolean	connectionFailed(Throwable cause)	Called when the connection to the server or upstream chained proxy fails.
(package private) void	connectionSucceeded(boolean shouldForwardInitialRequest)	Do all the stuff that needs to be done after our ConnectionFlow has succeeded.
(package private) static ProxyToServerConnection	create(DefaultHttpProxyServer proxyServer, ClientToProxyConnection clientConnection, String serverHostAndPort, HttpFilters initialFilters, HttpRequest initialHttpRequest, GlobalTrafficShapingHandler globalTrafficShapingHandler)	Create a new ProxyToServerConnection.
protected void	disconnected()	This method is called as soon as the underlying Channel becomes disconnected.
protected void	exceptionCaught(Throwable cause)	Override this to handle exceptions that occurred during asynchronous processing on the Channel.
ChainedProxy	getChainedProxy()
InetSocketAddress	getChainedProxyAddress()
ChainedProxyType	getChainedProxyType()
protected HttpFilters	getHttpFiltersFromProxyServer(HttpRequest httpRequest)	Request the ProxyServer for Filters.
HttpRequest	getInitialRequest()
InetSocketAddress	getRemoteAddress()
String	getServerHostAndPort()
TransportProtocol	getTransportProtocol()
boolean	hasUpstreamChainedProxy()
private void	initChannelPipeline(ChannelPipeline pipeline, HttpRequest httpRequest)	Initialize our ChannelPipeline to connect the upstream server.
private void	initializeConnectionFlow()	This method initializes our ConnectionFlow based on however this connection has been configured.
protected void	read(Object msg)	Read is invoked automatically by Netty as messages arrive on the socket.
protected void	readHAProxyMessage(HAProxyMessage msg)	Read an HAProxyMessage
protected void	readHTTPChunk(HttpContent chunk)	Implement this to handle reading a chunk in a chunked transfer.
protected ConnectionState	readHTTPInitial(HttpResponse httpResponse)	Implement this to handle reading the initial object (e.g.
protected void	readRaw(ByteBuf buf)	Implement this to handle reading a raw buffer as they are used in HTTP tunneling.
private void	rememberCurrentResponse(HttpResponse response)	Keeps track of the current HttpResponse so that we can associate its headers with future related chunks for this same transfer.
private void	removeHandlerIfPresent(String name)
private void	resetConnectionForRetry()	Convenience method to prepare to retry this connection.
private void	resetInitialRequest()
private void	respondWith(HttpObject httpObject)	Respond to the client with the given HttpObject.
private void	setupConnectionParameters()	Set up our connection parameters based on server address and chained proxies.
(package private) void	switchToWebSocketProtocol()
protected void	timedOut()	This method is called when the underlying Channel times out due to an idle timeout.
private static InetSocketAddress	unresolvedAddressFor(String hostAndPort)	Similar to addressFor(String, DefaultHttpProxyServer) except that it does not resolve the address.
(package private) ChannelFuture	write(Object msg)	This method is called by users of the ProxyConnection to send stuff out over the socket.
(package private) void	write(Object msg, HttpFilters filters)	Like write(Object) and also sets the current filters to the given value.
protected ChannelFuture	writeHttp(HttpObject httpObject)	Writes HttpObjects to the connection asynchronously.

Methods inherited from class org.littleshoot.proxy.impl.ProxyConnection

aggregateContentForFiltering, channelActive, channelInactive, channelRead0, channelRegistered, channelUnregistered, channelWritabilityChanged, connected, disconnect, doWrite, encrypt, encrypt, EncryptChannel, exceptionCaught, getCurrentState, getLOG, getSslEngine, is, isConnecting, isSaturated, isTunneling, removeHandlerIfPresent, resumeReading, stopReading, userEventTriggered, writeRaw, writeToChannel

Methods inherited from class io.netty.channel.SimpleChannelInboundHandler

acceptInboundMessage, channelRead

Methods inherited from class io.netty.channel.ChannelInboundHandlerAdapter

channelReadComplete

Methods inherited from class io.netty.channel.ChannelHandlerAdapter

ensureNotSharable, handlerAdded, handlerRemoved, isSharable

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface io.netty.channel.ChannelHandler

handlerAdded, handlerRemoved

Field Details

HTTP_ENCODER_NAME

private static final String HTTP_ENCODER_NAME

See Also:

• Constant Field Values

HTTP_DECODER_NAME

private static final String HTTP_DECODER_NAME

See Also:

• Constant Field Values

HTTP_PROXY_ENCODER_NAME

private static final String HTTP_PROXY_ENCODER_NAME

See Also:

• Constant Field Values

HTTP_REQUEST_WRITTEN_MONITOR_NAME

private static final String HTTP_REQUEST_WRITTEN_MONITOR_NAME

See Also:

• Constant Field Values

HTTP_RESPONSE_READ_MONITOR_NAME

private static final String HTTP_RESPONSE_READ_MONITOR_NAME

See Also:

• Constant Field Values

SOCKS_ENCODER_NAME

private static final String SOCKS_ENCODER_NAME

See Also:

• Constant Field Values

SOCKS_DECODER_NAME

private static final String SOCKS_DECODER_NAME

See Also:

• Constant Field Values

MAIN_HANDLER_NAME

private static final String MAIN_HANDLER_NAME

See Also:

• Constant Field Values

clientConnection

private final ClientToProxyConnection clientConnection

serverConnection

private final ProxyToServerConnection serverConnection

transportProtocol

private volatile TransportProtocol transportProtocol

chainedProxyType

private volatile ChainedProxyType chainedProxyType

remoteAddress

private volatile InetSocketAddress remoteAddress

localAddress

private volatile InetSocketAddress localAddress

remoteAddressResolver

private volatile io.netty.resolver.AddressResolverGroup<?> remoteAddressResolver

username

private volatile String username

password

private volatile String password

serverHostAndPort

private final String serverHostAndPort

chainedProxy

private volatile ChainedProxy chainedProxy

availableChainedProxies

private final Queue<ChainedProxy> availableChainedProxies

currentFilters

private volatile HttpFilters currentFilters

The filters to apply to response/chunks received from server.

connectionFlow

private volatile ConnectionFlow connectionFlow

Encapsulates the flow for establishing a connection, which can vary depending on how things are configured.

disableSni

private volatile boolean disableSni

Disables SNI when initializing connection flow in initializeConnectionFlow(). This value is set to true when retrying a connection without SNI to work around Java's SNI handling issue (see connectionFailed(Throwable)).

connectLock

private final Object connectLock

While we're in the process of connecting, it's possible that we'll receive a new message to write. This lock helps us synchronize and wait for the connection to be established before writing the next message.

initialRequest

private volatile HttpRequest initialRequest

This is the initial request received prior to connecting. We keep track of it so that we can process it after connection finishes.

currentHttpRequest

private volatile HttpRequest currentHttpRequest

Keeps track of HttpRequests that have been issued so that we can associate them with responses that we get back

currentHttpResponse

private volatile HttpResponse currentHttpResponse

While we're doing a chunked transfer, this keeps track of the initial HttpResponse object for our transfer (which is useful for its headers).

trafficHandler

private final GlobalTrafficShapingHandler trafficHandler

Limits bandwidth when throttling is enabled.

MINIMUM_RECV_BUFFER_SIZE_BYTES

private static final int MINIMUM_RECV_BUFFER_SIZE_BYTES

Minimum size of the adaptive recv buffer when throttling is enabled.

See Also:

• Constant Field Values

ConnectChannel

private final ConnectionFlowStep ConnectChannel

Opens the socket connection.

HTTPCONNECTWithChainedProxy

private final ConnectionFlowStep HTTPCONNECTWithChainedProxy

Writes the HTTP CONNECT to the server and waits for a 200 response.

SOCKS4CONNECTWithChainedProxy

private final ConnectionFlowStep SOCKS4CONNECTWithChainedProxy

Establishes a SOCKS4 connection.

SOCKS5InitialRequest

private final ConnectionFlowStep SOCKS5InitialRequest

Initiates a SOCKS5 connection.

SOCKS5SendPasswordCredentials

private final ConnectionFlowStep SOCKS5SendPasswordCredentials

Sends SOCKS5 password credentials after SOCKS5InitialRequest has completed.

SOCKS5CONNECTRequestWithChainedProxy

private final ConnectionFlowStep SOCKS5CONNECTRequestWithChainedProxy

Establishes a SOCKS5 connection after SOCKS5InitialRequest and (optionally) SOCKS5SendPasswordCredentials have completed.

MitmEncryptClientChannel

private final ConnectionFlowStep MitmEncryptClientChannel

Encrypts the client channel based on our server SSLSession.

This does not wait for the handshake to finish so that we can go on and respond to the CONNECT request.

bytesReadMonitor

private final ProxyConnection<HttpResponse>.BytesReadMonitor bytesReadMonitor

responseReadMonitor

private final ProxyConnection<HttpResponse>.ResponseReadMonitor responseReadMonitor

bytesWrittenMonitor

private final ProxyConnection<HttpResponse>.BytesWrittenMonitor bytesWrittenMonitor

requestWrittenMonitor

private final ProxyConnection.RequestWrittenMonitor requestWrittenMonitor

Constructor Details

ProxyToServerConnection

private ProxyToServerConnection(DefaultHttpProxyServer proxyServer,
 ClientToProxyConnection clientConnection,
 String serverHostAndPort,
 ChainedProxy chainedProxy,
 Queue<ChainedProxy> availableChainedProxies,
 HttpFilters initialFilters,
 GlobalTrafficShapingHandler globalTrafficShapingHandler)
                         throws UnknownHostException

Throws:

UnknownHostException

Method Details

create

static ProxyToServerConnection create(DefaultHttpProxyServer proxyServer,
 ClientToProxyConnection clientConnection,
 String serverHostAndPort,
 HttpFilters initialFilters,
 HttpRequest initialHttpRequest,
 GlobalTrafficShapingHandler globalTrafficShapingHandler)
                               throws UnknownHostException

Create a new ProxyToServerConnection.

Throws:

UnknownHostException

read

protected void read(Object msg)

Description copied from class: ProxyConnection

Read is invoked automatically by Netty as messages arrive on the socket.

Overrides:

read in class ProxyConnection<HttpResponse>

readHAProxyMessage

protected void readHAProxyMessage(HAProxyMessage msg)

Description copied from class: ProxyConnection

Read an HAProxyMessage

Specified by:

readHAProxyMessage in class ProxyConnection<HttpResponse>

Parameters:

msg - HAProxyMessage

readHTTPInitial

protected ConnectionState readHTTPInitial(HttpResponse httpResponse)

Description copied from class: ProxyConnection

Implement this to handle reading the initial object (e.g. HttpRequest or HttpResponse).

Specified by:

readHTTPInitial in class ProxyConnection<HttpResponse>

readHTTPChunk

protected void readHTTPChunk(HttpContent chunk)

Description copied from class: ProxyConnection

Implement this to handle reading a chunk in a chunked transfer.

Specified by:

readHTTPChunk in class ProxyConnection<HttpResponse>

readRaw

protected void readRaw(ByteBuf buf)

Description copied from class: ProxyConnection

Implement this to handle reading a raw buffer as they are used in HTTP tunneling.

Specified by:

readRaw in class ProxyConnection<HttpResponse>

write

void write(Object msg,
 HttpFilters filters)

Like write(Object) and also sets the current filters to the given value.

write

ChannelFuture write(Object msg)

Description copied from class: ProxyConnection

This method is called by users of the ProxyConnection to send stuff out over the socket.

Overrides:

write in class ProxyConnection<HttpResponse>

writeHttp

protected ChannelFuture writeHttp(HttpObject httpObject)

Description copied from class: ProxyConnection

Writes HttpObjects to the connection asynchronously.

Overrides:

writeHttp in class ProxyConnection<HttpResponse>

become

protected void become(ConnectionState newState)

Description copied from class: ProxyConnection

Updates the current state to the given value.

Overrides:

become in class ProxyConnection<HttpResponse>

becameSaturated

protected void becameSaturated()

Description copied from class: ProxyConnection

Callback that's invoked if this connection becomes saturated.

Overrides:

becameSaturated in class ProxyConnection<HttpResponse>

becameWritable

protected void becameWritable()

Description copied from class: ProxyConnection

Callback that's invoked when this connection becomes writeable again.

Overrides:

becameWritable in class ProxyConnection<HttpResponse>

timedOut

protected void timedOut()

Description copied from class: ProxyConnection

This method is called when the underlying Channel times out due to an idle timeout.

Overrides:

timedOut in class ProxyConnection<HttpResponse>

disconnected

protected void disconnected()

Description copied from class: ProxyConnection

This method is called as soon as the underlying Channel becomes disconnected.

Overrides:

disconnected in class ProxyConnection<HttpResponse>

exceptionCaught

protected void exceptionCaught(Throwable cause)

Description copied from class: ProxyConnection

Override this to handle exceptions that occurred during asynchronous processing on the Channel.

Overrides:

exceptionCaught in class ProxyConnection<HttpResponse>

getTransportProtocol

public TransportProtocol getTransportProtocol()

getChainedProxyType

public ChainedProxyType getChainedProxyType()

getRemoteAddress

public InetSocketAddress getRemoteAddress()

getServerHostAndPort

public String getServerHostAndPort()

hasUpstreamChainedProxy

public boolean hasUpstreamChainedProxy()

getChainedProxyAddress

public InetSocketAddress getChainedProxyAddress()

getChainedProxy

public ChainedProxy getChainedProxy()

getInitialRequest

public HttpRequest getInitialRequest()

getHttpFiltersFromProxyServer

protected HttpFilters getHttpFiltersFromProxyServer(HttpRequest httpRequest)

Description copied from class: ProxyConnection

Request the ProxyServer for Filters. By default, no-op filters are returned by DefaultHttpProxyServer. Subclasses of ProxyConnection can change this behaviour.

Overrides:

getHttpFiltersFromProxyServer in class ProxyConnection<HttpResponse>

Parameters:

httpRequest - Filter attached to the give HttpRequest (if any)

rememberCurrentResponse

private void rememberCurrentResponse(HttpResponse response)

Keeps track of the current HttpResponse so that we can associate its headers with future related chunks for this same transfer.

respondWith

private void respondWith(HttpObject httpObject)

Respond to the client with the given HttpObject.

connectAndWrite

private void connectAndWrite(HttpRequest initialRequest)

Configures the connection to the upstream server and begins the ConnectionFlow.

Parameters:

initialRequest - the current HTTP request being handled

initializeConnectionFlow

private void initializeConnectionFlow()

This method initializes our ConnectionFlow based on however this connection has been configured. If the disableSni value is true, this method will not pass peer information to the MitmManager when handling CONNECTs.

addFirstOrReplaceHandler

private void addFirstOrReplaceHandler(String name,
 ChannelHandler handler)

removeHandlerIfPresent

private void removeHandlerIfPresent(String name)

connectionFailed

protected boolean connectionFailed(Throwable cause)
                            throws UnknownHostException

Called when the connection to the server or upstream chained proxy fails. This method may return true to indicate that the connection should be retried. If returning true, this method must set up the connection itself.

Parameters:

cause - the reason that our attempt to connect failed (can be null)

Returns:

true if we are trying to fall back to another connection

Throws:

UnknownHostException

resetConnectionForRetry

private void resetConnectionForRetry()
                              throws UnknownHostException

Convenience method to prepare to retry this connection. Closes the connection's channel and sets up the connection again using setupConnectionParameters().

Throws:

UnknownHostException - when setupConnectionParameters() is unable to resolve the hostname

setupConnectionParameters

private void setupConnectionParameters()
                                throws UnknownHostException

Set up our connection parameters based on server address and chained proxies.

Throws:

UnknownHostException - when unable to resolve the hostname to an IP address

initChannelPipeline

private void initChannelPipeline(ChannelPipeline pipeline,
 HttpRequest httpRequest)

Initialize our ChannelPipeline to connect the upstream server. LittleProxy acts as a client here. A ChannelPipeline invokes the read (Inbound) handlers in ascending ordering of the list and then the write (Outbound) handlers in descending ordering. Regarding the Javadoc of HttpObjectAggregator it's needed to have the HttpResponseEncoder or HttpRequestEncoder before the HttpObjectAggregator in the ChannelPipeline.

connectionSucceeded

void connectionSucceeded(boolean shouldForwardInitialRequest)

Do all the stuff that needs to be done after our ConnectionFlow has succeeded.

Parameters:

shouldForwardInitialRequest - whether or not we should forward the initial HttpRequest to the server after the connection has been established.

resetInitialRequest

private void resetInitialRequest()

addressFor

public static InetSocketAddress addressFor(String hostAndPort,
 DefaultHttpProxyServer proxyServer)
                                    throws UnknownHostException

Build an InetSocketAddress for the given hostAndPort.

Parameters:

hostAndPort - String representation of the host and port

proxyServer - the current DefaultHttpProxyServer

Returns:

a resolved InetSocketAddress for the specified hostAndPort

Throws:

UnknownHostException - if hostAndPort could not be resolved, or if the input string could not be parsed into a host and port.

unresolvedAddressFor

private static InetSocketAddress unresolvedAddressFor(String hostAndPort)

Similar to addressFor(String, DefaultHttpProxyServer) except that it does not resolve the address.

Parameters:

hostAndPort - the host and port to parse.

Returns:

an unresolved InetSocketAddress.

switchToWebSocketProtocol

void switchToWebSocketProtocol()