Update changelog and proto docs

CHANGELOG

@@ -16,6 +16,8 @@ CHANGES:
 		does not include localhost.
 	- The client will now exit if configuring IP or MTU fails.
 	- The starting cache miss value is randomized at startup, fixes #65.
+	- Raw UDP mode added. If the iodined server is reachable directly,
+		packets can be sent to it without DNS encoding. Fixes #36.
 
 2009-06-01: 0.5.2 "WifiFree"
 	- Fixed client segfault on OS X, #57

doc/proto_00000501.txt

@@ -3,6 +3,8 @@ Detailed specification of protocol in version 00000501
 
 Note: work in progress!!
 
+======================================================
+1. DNS protocol
 ======================================================
 
 CMC = 2 byte Cache Miss Counter, increased every time it is used
@@ -125,3 +127,31 @@ The server response to Ping and Data packets is a DNS NULL type response:
 If server has nothing to send, data length is 0 bytes.
 If server has something to send, it will send a downstream data packet, 
 prefixed with 2 bytes header as shown above.
+
+
+======================================================
+2. Raw UDP protocol
+======================================================
+
+All Raw UDP protcol messages start with a 3 byte header: 0x10d19e
+This is not the start of a valid DNS message so it is easy to identify.
+The fourth byte contains the command and the user id.
+
+	 7654 3210
+	+----+----+
+	|CCCC|UUUU|
+	+----+----+
+
+Login message (command = 1):
+The header is followed by a MD5 hash with the same password as in the DNS
+login. The client starts the raw mode by sending this message, and uses
+the login challenge +1, and the server responds using the login challenge -1.
+After the login message has been exchanged, both the server and the client
+switch to raw udp mode for the rest of the connection.
+
+Data message (command = 2):
+After the header comes the payload data, which may be compressed.
+
+Ping message (command = 3):
+Sent from client to server and back to keep session open. Has no payload.
+