crypto/tls: check in support code.

This support code helps in generating the handshake scripts
which are used for testing.

R=rsc, ality
CC=golang-dev
https://golang.org/cl/3680041

src/pkg/crypto/tls/handshake_server_test.go

@@ -189,10 +189,11 @@ var testPrivateKey = &rsa.PrivateKey{
 }
 
 // Script of interaction with gnutls implementation.
-// The values for this test are obtained by building a test binary (gotest)
-// and then running 6.out -serve to start a server and then
-// gnutls-cli --insecure --debug 100 -p 10443 localhost
-// to dump a session.
+// The values for this test are obtained by building and running in server mode:
+//   % gotest -match "TestRunServer" -serve
+// and then:
+//   % gnutls-cli --insecure --debug 100 -p 10443 localhost > /tmp/log 2>&1
+//   % python parse-gnutls-cli-debug-log.py < /tmp/log
 var rc4ServerScript = [][]byte{
 	{
 		0x16, 0x03, 0x02, 0x00, 0x7f, 0x01, 0x00, 0x00,

src/pkg/crypto/tls/parse-gnutls-cli-debug-log.py

+# Copyright 2010 The Go Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style
+# license that can be found in the LICENSE file.
+
+# This code is used to parse the debug log from gnutls-cli and generate a
+# script of the handshake. This script is included in handshake_server_test.go.
+# See the comments there for details.
+
+import sys
+
+blocks = []
+
+READ = 1
+WRITE = 2
+
+currentBlockType = 0
+currentBlock = []
+for line in sys.stdin.readlines():
+        line = line[:-1]
+        if line.startswith("|<7>| WRITE: "):
+                if currentBlockType != WRITE:
+                        if len(currentBlock) > 0:
+                                blocks.append(currentBlock)
+                        currentBlock = []
+                        currentBlockType = WRITE
+        elif line.startswith("|<7>| READ: "):
+                if currentBlockType != READ:
+                        if len(currentBlock) > 0:
+                                blocks.append(currentBlock)
+                        currentBlock = []
+                        currentBlockType = READ
+        elif line.startswith("|<7>| 0"):
+                line = line[13:]
+                line = line.strip()
+                bs = line.split()
+                for b in bs:
+                        currentBlock.append(int(b, 16))
+
+if len(currentBlock) > 0:
+        blocks.append(currentBlock)
+
+for block in blocks:
+        sys.stdout.write("\t{\n")
+
+        i = 0
+        for b in block:
+                if i % 8 == 0:
+                        sys.stdout.write("\t\t")
+                sys.stdout.write("0x%02x," % b)
+                if i % 8 == 7:
+                        sys.stdout.write("\n")
+                else:
+                        sys.stdout.write(" ")
+                i += 1
+        sys.stdout.write("\n\t},\n\n")