From 25018c9b15dec5fc0781b48c7fa65ffa1a49adb9 Mon Sep 17 00:00:00 2001
From: Erik Ekman <yarrick@kryo.se>
Date: Sun, 7 Dec 2008 09:41:06 +0000
Subject: [PATCH] updated docs

---
 doc/proto_00000403.txt | 88 ++++++++++++++----------------------------
 1 file changed, 29 insertions(+), 59 deletions(-)

diff --git a/doc/proto_00000403.txt b/doc/proto_00000403.txt
index fa8b0b3..f1dbad9 100644
--- a/doc/proto_00000403.txt
+++ b/doc/proto_00000403.txt
@@ -1,98 +1,68 @@
 Detailed specification of protocol in version 00000403
 ======================================================
 
-This protocol varies a lot from earlier ones and will
-hopefully give cleaner code and enable more features.
-
-Common header:
-
- 7654 3210
-+----+----+
-|CCCC|UUUU|
-+----+----+
-
-CCCC = Command
-UUUU = User id
-
-Commands:
-0: Version
-1: Login
-2: Case check
-3: Codec switch
-4: Data
-5: Ping
-6: -
-7: -
-8: -
-9: -
-A: -Reserved- (So header byte will never encode to a v)
-B: -
-C: -
-D: - 
-E: -
-F: -
-
 CMC = 2 byte Cache Miss Counter, increased every time it is used
 
 Version:
 Client sends:
-	Command = 0x0, User = 0xF
-	Data is 4 bytes big endian protocol version
-	Ends with CMC
+	First byte v or V
+	Rest encoded with base32:
+	4 bytes big endian protocol version
+	CMC
 Server replies:
-	Command = 0x0, User = userid
-	Then 4 chars, followed by big endian int:
+	4 chars:
 		VACK (version ok), followed by login challenge
 		VNAK (version differs), followed by server protocol version
 		VFUL (server has no free slots), followed by max users
+	4 byte value: means login challenge/server protocol version/max users
+	1 byte userid of the new user, or any byte if not VACK
 	
 Login:
-Command = 0x1, User = userid from version reply
 Client sends:
+	First byte l or L
+	Rest encoded with base32:
+	1 byte userid
 	16 bytes MD5 hash of: (first 32 bytes of password) xor (8 repetitions of login challenge)
-	Ends with CMC
+	CMC
 Server replies:
-	4 chars, then maybe three ints
-	LACK serverip clientip mtu means login accepted
 	LNAK means not accepted
+	x.x.x.x-y.y.y.y-mtu means accepted (server ip, client ip, mtu)
 
 Case check:
-Command = 0x2, User = userid from version reply
 Client sends: 
+	First byte z or Z
 	Lots of data that should not be decoded
 Server replies:
 	The requested domain copied raw
 
 Switch codec:
-Command = 0x03, User = userid
 Client sends:
-	One byte, with value 5 or 6, representing number of bits per byte in encoding
+	First byte s or S
+	One byte ASCII digit, meaning userid
+	One byte ASCII digit, with value 5 or 6, representing number of bits per byte in encoding
 Server sends:
-	Name of codec if accepted. After this all upstream packets must be encoded with the new codec.
-	BADCODEC if not accepted. Client must then revert to Base64
+	Name of codec if accepted. After this all upstream data packets must be encoded with the new codec.
+	BADCODEC if not accepted. Client must then revert to Base32
 
 Data:
-Command = 0x04, User = userid
 Data header:
-	 76543210 7 6 543210
-	+--------+-+-+------+
-	|SSSSSSSS|L|C|FFFFFF|
-	+--------+-+-+------+
+	 321 0 
+	+---+-+
+	|UUU|L|
+	+---+-+
 
-SSSSSSSS = Packet sequence number
+UUU = Userid
 L = Last fragment in packet flag
-C = Compression used flag
-FFFFFF = Fragment index in packet
 
-The data header is used both by the server and the client, followed by a fragment.
-Packet and fragment numbers are used to detect retransmits by dns relay.
-When a fragment arrives with L bit set, the packet should be pushed to the tun device.
-If the C bit is set, it should be decompressed before sent to tun device.
+First 4 bits coded as hex in ASCII. 
+Followed by data encoded with the chosen codec.
 
 Ping:
 Command = 0x04, User = userid
 Client sends:
 	Only a CMC
-Server replies:
-	With a Data packet or 0 bytes.
 
+The server responses 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 a packet to send, data length is set and the data is a full raw
+unencoded ip packet, prefixed with 32 bits tun data.