Mention updated config files.

[rsync.git] / csprotocol.txt

diff --git a/csprotocol.txt b/csprotocol.txt
index b41c20fb0eb19a52e76fbf8566287a8dbf63e555..7ba09ab02ebbf32b4734d4a174010b95034bbc9b 100644 (file)
--- a/csprotocol.txt
+++ b/csprotocol.txt
@@ -3,42 +3,58 @@ basically a summary of clientserver.c and authenticate.c.
 
  -- Martin Pool <mbp@samba.org>
 
-$Id$
-
-
-
 
 This is the protocol used for rsync --daemon; i.e. connections to port
 873 rather than invocations over a remote shell.
 
-When the server accepts a connection, it prints a greeting
+When the server accepts a connection, it prints a newline-terminated
+greeting line:
 
-  @RSYNCD: <version>
+  @RSYNCD: <version>.<subprotocol> <digest1> <digestN>
 
-where <version> is the numeric version; currently 24.  It follows this
-with a free text message-of-the-day.  It expects to see a similar
-greeting back from the client.
+The <version> is the numeric version (see PROTOCOL_VERSION in rsync.h)
+The <subprotocol> is the numeric subprotocol version (which is 0 for a
+final protocol version, as the SUBPROTOCOL_VERSION define discusses).
+The <digestN> names are the authentication digest algorithms that the
+daemon supports, listed in order of preference.
+
+An rsync prior to 3.2.7 omits the digest names.  An rsync prior to 3.0.0
+also omits the period and the <subprotocol> value.  Since a final
+protocol has a subprotocol value of 0, a missing subprotocol value is
+assumed to be 0 for any protocol prior to 30.  It is considered a fatal
+error for protocol 30 and above to omit it.  It is considered a fatal
+error for protocol 32 and above to omit the digest name list (currently
+31 is the newest protocol).
+
+The daemon expects to see a similar greeting line back from the client.
+Once received, the daemon follows the opening line with a free-format
+text message-of-the-day (if any is defined).
 
 The server is now in the connected state.  The client can either send
-the command
+the command:
 
   #list
 
-to get a listing of modules, or the name of a module.  After this, the
+(to get a listing of modules) or the name of a module.  After this, the
 connection is now bound to a particular module.  Access per host for
 this module is now checked, as is per-module connection limits.
 
-If authentication is required to use this module, the server will say
+If authentication is required to use this module, the server will say:
 
   @RSYNCD: AUTHREQD <challenge>
 
 where <challenge> is a random string of base64 characters.  The client
-must respond with
+must respond with:
 
   <user> <response>
 
-where <user> is the username they claim to be, and <response> is the
-base64 form of the MD4 hash of challenge+password.
+The <user> is the username they claim to be. The <response> is the
+base64 form of the digest hash of the challenge+password string. The
+chosen digest method is the most preferred client method that is also in
+the server's list.  If no digest list was explicitly provided, the side
+expecting a list assumes the other side provided either the single name
+"md5" (for a negotiated protocol 30 or 31), or the single name "md4"
+(for an older protocol).
 
 At this point the server applies all remaining constraints before
 handing control to the client, including switching uid/gid, setting up
@@ -72,3 +88,23 @@ stay tuned (or write it yourself!).
 
 
 
+------------
+Protocol version changes
+
+31     (2013-09-28, 3.1.0)
+
+       Initial release of protocol 31 had no changes.  Rsync 3.2.7
+       introduced the suffixed list of digest names on the greeting
+       line.  The presence of the list is allowed even if the greeting
+       indicates an older protocol version number.
+
+30     (2007-10-04, 3.0.0pre1)
+
+       The use of a ".<subprotocol>" number was added to
+       @RSYNCD: <version>.<subprotocol>
+
+25     (2001-08-20, 2.4.7pre2) 
+
+       Send an explicit "@RSYNC EXIT" command at the end of the
+       module listing.  We never intentionally end the transmission
+       by just closing the socket anymore.