mirror of
https://github.com/yarrick/iodine.git
synced 2024-11-25 15:41:26 +00:00
158 lines
4.6 KiB
Plaintext
158 lines
4.6 KiB
Plaintext
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
|
|
|
|
Version:
|
|
Client sends:
|
|
First byte v or V
|
|
Rest encoded with base32:
|
|
4 bytes big endian protocol version
|
|
CMC
|
|
Server replies:
|
|
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:
|
|
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)
|
|
CMC
|
|
Server replies:
|
|
LNAK means not accepted
|
|
x.x.x.x-y.y.y.y-mtu-netmask means accepted (server ip, client ip, mtu, netmask bits)
|
|
|
|
IP Request:
|
|
Client sends:
|
|
First byte i or I
|
|
5 bits coded as Base32 char, meaning userid
|
|
CMC
|
|
Server replies
|
|
BADIP if bad userid, or
|
|
I and then 4 bytes network order external IP address of iodined server
|
|
|
|
Case check:
|
|
Client sends:
|
|
First byte z or Z
|
|
Lots of data that should not be decoded
|
|
Server replies:
|
|
The requested domain copied raw
|
|
|
|
Switch codec:
|
|
Client sends:
|
|
First byte s or S
|
|
5 bits coded as Base32 char, meaning userid
|
|
5 bits coded as Base32 char, with value 5 or 6, representing number of raw
|
|
bits per encoded byte
|
|
CMC
|
|
Server sends:
|
|
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
|
|
BADLEN if length of query is too short
|
|
|
|
Probe downstream fragment size:
|
|
Client sends:
|
|
First byte r or R
|
|
15 bits coded as 3 Base32 chars: UUUUF FFFFF FFFFF
|
|
meaning 4 bits userid, 11 bits fragment size
|
|
Then follows a long random query which contents does not matter
|
|
Server sends:
|
|
Requested number of bytes as a response. The first two bytes contains
|
|
the requested length. Rest of message can be any data.
|
|
BADFRAG if requested length not accepted.
|
|
|
|
Set downstream fragment size:
|
|
Client sends:
|
|
First byte n or N
|
|
Rest encoded with base32:
|
|
1 byte userid
|
|
2 bytes new downstream fragment size
|
|
CMC
|
|
Server sends:
|
|
2 bytes new downstream fragment size. After this all downstream
|
|
payloads will be max (fragsize + 2) bytes long.
|
|
BADFRAG if not accepted.
|
|
|
|
Data:
|
|
Upstream data header:
|
|
3210 432 10 43 210 4321 0
|
|
+----+---+--+--+---+----+-+
|
|
|UUUU|SSS|FF|FF|DDD|GGGG|L|
|
|
+----+---+--+--+---+----+-+
|
|
|
|
Downstream data header:
|
|
7 654 3210 765 4321 0
|
|
+-+---+----+---+----+-+
|
|
|C|SSS|FFFF|DDD|GGGG|L|
|
|
+-+---+----+---+----+-+
|
|
|
|
UUUU = Userid
|
|
L = Last fragment in packet flag
|
|
SS = Upstream packet sequence number
|
|
FFFF = Upstream fragment number
|
|
DDD = Downstream packet sequence number
|
|
GGGG = Downstream fragment number
|
|
C = Compression enabled for downstream packet
|
|
|
|
Upstream data packet starts with 1 byte ASCII hex coded user byte, then 3 bytes
|
|
Base32 encoded header, then comes the payload data, encoded with chosen codec.
|
|
|
|
Downstream data starts with 2 byte header. Then payload data, which may be
|
|
compressed.
|
|
|
|
Ping:
|
|
Client sends:
|
|
First byte p or P
|
|
Rest encoded with Base32:
|
|
1 byte with 4 bits userid
|
|
1 byte with:
|
|
3 bits downstream seqno
|
|
4 bits downstream fragment
|
|
CMC
|
|
|
|
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.
|
|
|