1 files changed, 96 insertions, 0 deletions
diff --git a/common/socks5/args.go b/common/socks5/args.go
new file mode 100644
index 0000000..d9ea099
--- /dev/null
+++ b/common/socks5/args.go
@@ -0,0 +1,96 @@
+/*
+ * 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 socks5
+
+import (
+	"fmt"
+	"git.torproject.org/pluggable-transports/goptlib.git"
+)
+
+// parseClientParameters takes a client parameter string formatted according to
+// "Passing PT-specific parameters to a client PT" in the pluggable transport
+// specification, and returns it as a goptlib Args structure.
+//
+// This is functionally identical to the equivalently named goptlib routine.
+func parseClientParameters(argStr string) (args pt.Args, err error) {
+	args = make(pt.Args)
+	if len(argStr) == 0 {
+		return
+	}
+
+	var key string
+	var acc []byte
+	prevIsEscape := false
+	for idx, ch := range []byte(argStr) {
+		switch ch {
+		case '\\':
+			prevIsEscape = !prevIsEscape
+			if prevIsEscape {
+				continue
+			}
+		case '=':
+			if !prevIsEscape {
+				if key != "" {
+					break
+				}
+				if len(acc) == 0 {
+					return nil, fmt.Errorf("unexpected '=' at %d", idx)
+				}
+				key = string(acc)
+				acc = nil
+				continue
+			}
+		case ';':
+			if !prevIsEscape {
+				if key == "" || idx == len(argStr)-1 {
+					return nil, fmt.Errorf("unexpected ';' at %d", idx)
+				}
+				args.Add(key, string(acc))
+				key = ""
+				acc = nil
+				continue
+			}
+		default:
+			if prevIsEscape {
+				return nil, fmt.Errorf("unexpected '\\' at %d", idx-1)
+			}
+		}
+		prevIsEscape = false
+		acc = append(acc, ch)
+	}
+	if prevIsEscape {
+		return nil, fmt.Errorf("underminated escape character")
+	}
+	// Handle the final k,v pair if any.
+	if key == "" {
+		return nil, fmt.Errorf("final key with no value")
+	}
+	args.Add(key, string(acc))
+
+	return args, nil
+}