Wire in go.net/proxy, enabling SOCKS5 via TOR_PT_PROXY.

With tor patched to support 8402, obfs4 bootstraps via a SOCKSv5 proxy
now.  Other schemes will bail with a PROXY-ERROR, as the go.net/proxy
package does not support them, and I have not gotten around to writing
dialers for them yet (next on my TODO list).

Part of issue #7.

1 files changed, 51 insertions, 0 deletions

diff --git a/obfs4proxy/proxy_extras.go b/obfs4proxy/proxy_extras.go
new file mode 100644
index 0000000..27b638b
--- /dev/null
+++ b/obfs4proxy/proxy_extras.go
@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2014, 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 main
+
+import (
+	"net/url"
+
+	"code.google.com/p/go.net/proxy"
+
+	"github.com/yawning/obfs4"
+)
+
+// getProxyDialer is a trival wrapper around the go.net/proxy package to avoid
+// having it as a dependency for anything else.
+func getProxyDialer(uri *url.URL) (obfs4.DialFn, error) {
+	if uri == nil {
+		return proxy.Direct.Dial, nil
+	}
+
+	dialer, err := proxy.FromURL(uri, proxy.Direct)
+	if err != nil {
+		return nil, err
+	}
+
+	return dialer.Dial, nil
+}