From 611205be681322883a4d73dd00fcb13c4352fe53 Mon Sep 17 00:00:00 2001
From: Yawning Angel <yawning@torproject.org>
Date: Thu, 29 Oct 2015 17:29:21 +0000
Subject: Add the "meek_lite" transport, which does what one would expect.

This is a meek client only implementation, with the following
differences with dcf's `meek-client`:

 - It is named `meek_lite` to differentiate it from the real thing.
 - It does not support using an external helper to normalize TLS
   signatures, so adversaries can look for someone using the Go
   TLS library to do HTTP.
 - It does the right thing with TOR_PT_PROXY, even when a helper is
   not present.

Most of the credit goes to dcf, who's code I librerally cribbed and
stole.  It is intended primarily as a "better than nothina" option
for enviornments that do not or can not presently use an external
Firefox helper.
---
 transports/meeklite/base.go | 89 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 89 insertions(+)
 create mode 100644 transports/meeklite/base.go

(limited to 'transports/meeklite/base.go')

diff --git a/transports/meeklite/base.go b/transports/meeklite/base.go
new file mode 100644
index 0000000..2a4cf80
--- /dev/null
+++ b/transports/meeklite/base.go
@@ -0,0 +1,89 @@
+/*
+ * Copyright (c) 2015, Yawning Angel <yawning at torproject dot org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  * Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *
+ *  * Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+// Package meeklite provides an implementation of the Meek circumvention
+// protocol.  Only a client implementation is provided, and no effort is
+// made to normalize the TLS fingerprint.
+//
+// It borrows quite liberally from the real meek-client code.
+package meeklite
+
+import (
+	"fmt"
+	"net"
+
+	"git.torproject.org/pluggable-transports/goptlib.git"
+	"git.torproject.org/pluggable-transports/obfs4.git/transports/base"
+)
+
+const transportName = "meek_lite"
+
+// Transport is the Meek implementation of the base.Transport interface.
+type Transport struct{}
+
+// Name returns the name of the Meek transport protocol.
+func (t *Transport) Name() string {
+	return transportName
+}
+
+// ClientFactory returns a new meekClientFactory instance.
+func (t *Transport) ClientFactory(stateDir string) (base.ClientFactory, error) {
+	cf := &meekClientFactory{transport: t}
+	return cf, nil
+}
+
+// ServerFactory will one day return a new meekServerFactory instance.
+func (t *Transport) ServerFactory(stateDir string, args *pt.Args) (base.ServerFactory, error) {
+	// TODO: Fill this in eventually, though for servers people should
+	// just use the real thing.
+	return nil, fmt.Errorf("server not supported")
+}
+
+type meekClientFactory struct {
+	transport base.Transport
+}
+
+func (cf *meekClientFactory) Transport() base.Transport {
+	return cf.transport
+}
+
+func (cf *meekClientFactory) ParseArgs(args *pt.Args) (interface{}, error) {
+	return newClientArgs(args)
+}
+
+func (cf *meekClientFactory) Dial(network, addr string, dialFn base.DialFunc, args interface{}) (net.Conn, error) {
+	// Validate args before opening outgoing connection.
+	ca, ok := args.(*meekClientArgs)
+	if !ok {
+		return nil, fmt.Errorf("invalid argument type for args")
+	}
+
+	return newMeekConn(network, addr, dialFn, ca)
+}
+
+var _ base.ClientFactory = (*meekClientFactory)(nil)
+var _ base.Transport = (*Transport)(nil)
-- 
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