[Documentation] Added a document to track problems with file transfer protocol extensions, included an e-mail from Peter Rosin on this subject.

git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@3401 3789f03b-4d11-0410-bbf8-ca57d06f2519
diff --git a/doc/ft-protocol-problems.txt b/doc/ft-protocol-problems.txt
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+From: Peter Rosin <peda@lysator.liu.se>

+To: vnc-tight-list@lists.sourceforge.net

+Date: Thu, 25 Sep 2008 10:21:07 +0200

+Message-ID: <48DB49F3.6030609@lysator.liu.se>

+Subject: Problems with timestamps in file transfers.

+

+Hi list!

+

+I'm writing some VNC client software that supports the the file

+transfer extensions described in the rfbtight.tex document in

+the svn repo. However, when I communicate with a TightVNC server

+version 1.3.9 (WinVNC.exe) I get strange data for the modification

+times of the files.

+

+Specifically, in the FileListData message, I have understood

+that directories are encoded as <size ~0, mod-time 0>. For

+regular files I get the expected size, but the mod-time is

+always 0xffffffe7 (-25) which seem totally bogus.

+

+The next problem is more disturbing since you will get interop

+problems if you fix it. In the last FileDownloadData message

+(the one with raw-length = compressed-length = 0), the mod-time

+is transmitted in little-endian byte order (at least my TightVNC

+server does so). Since it's more problems fixing this than

+documenting it, I think this endianness issue should be recorded

+in the rfbtight.tex file.

+

+(However, when you use FileUploadData you should transmit

+  the mod-time in the expected big-endian network byte order.)

+

+Cheers,

+Peter

+

+==================================================================

+