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Update documentation.

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Guus Sliepen 2002-09-15 22:19:38 +00:00
parent bf3a118988
commit 1dcbdf48eb
8 changed files with 212 additions and 486 deletions
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doc/PROTOCOL
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@ -12,7 +12,7 @@ This is the protocol documentation for tinc, a Virtual Private Network daemon.
provided that the entire resulting derived work is distributed
under the terms of a permission notice identical to this one.
$Id: PROTOCOL,v 1.1.2.7 2002/06/21 10:11:10 guus Exp $
$Id: PROTOCOL,v 1.1.2.8 2002/09/15 22:19:37 guus Exp $
1. Protocols used in tinc
@ -69,24 +69,62 @@ synchronised.
daemon message
--------------------------------------------------------------------------
origin ADD_EDGE node1 12.23.34.45 655 node2 21.32.43.54 655 222 0
| | | \___________________/ | +-> options
| | | | +----> weight
| | | +----------------> see below
| | +--> UDP port
| +----------> real address
+------------------> name of node on one side of the edge
origin ADD_EDGE node1 node2 21.32.43.54 655 222 0
| | | | | +-> options
| | | | +----> weight
| | | +--------> UDP port of node2
| | +----------------> real address of node2
| +-------------------------> name of destination node
+-------------------------------> name of source node
origin ADD_SUBNET node 192.168.1.0/24
| | +--> prefixlength
| +--------> IPv4 network address
| +--------> network address
+------------------> owner of this subnet
--------------------------------------------------------------------------
The ADD_EDGE messages are to inform other tinc daemons that a connection between
two nodes exist. The address of the destination node is available so that
VPN packets can be sent directly to that node.
The ADD_SUBNET messages inform other tinc daemons that certain subnets belong
to certain nodes. tinc will use it to determine to which node a VPN packet has
to be sent.
message
------------------------------------------------------------------
DEL_EDGE node1 node2
| +----> name of destination node
+----------> name of source node
DEL_SUBNET node 192.168.1.0/24
| | +--> prefixlength
| +--------> network address
+------------------> owner of this subnet
------------------------------------------------------------------
In case a connection between two daemons is closed or broken, DEL_EDGE messages
are sent to inform the other daemons of that fact. Each daemon will calculate a
new route to the the daemons, or mark them unreachable if there isn't any.
message
------------------------------------------------------------------
REQ_KEY origin destination
| +--> name of the tinc daemon it wants the key from
+----------> name of the daemon that wants the key
ANS_KEY origin destination 4ae0b0a82d6e0078 91 64 4
| | \______________/ | | +--> MAC length
| | | | +-----> digest algorithm
| | | +--------> cipher algorithm
| | +--> 128 bits key
| +--> name of the daemon that wants the key
+----------> name of the daemon that uses this key
KEY_CHANGED origin
+--> daemon that has changed it's packet key
--------------------------------------------------------------------------
The keys used to encrypt VPN packets are not sent out directly. This is
because it would generate a lot of traffic on VPNs with many daemons, and
chances are that not every tinc daemon will ever send a packet to every
@ -97,33 +135,17 @@ act as a proxy and forward its copy back to the requestor.
daemon message
--------------------------------------------------------------------------
daemon REQ_KEY origin destination
| +--> name of the tinc daemon it wants the key from
+----------> name of the daemon that wants the key
daemon ANS_KEY origin destination 4ae0b0a82d6e0078 91 64 4
| | \______________/ | | +--> MAC length
| | | | +-----> digest algorithm
| | | +--------> cipher algorithm
| | +--> 128 bits key
| +--> name of the daemon that wants the key
+----------> name of the daemon that uses this key
daemon KEY_CHANGED origin
+--> daemon that has changed it's packet key
origin PING
dest. PONG
--------------------------------------------------------------------------
There is also a mechanism to check if hosts are still alive. Since network
failures or a crash can cause a daemon to be killed without properly
shutting down the TCP connection, this is necessary to keep an up to date
connection list. Pings are sent at regular intervals, except when there
is also some other traffic.
daemon message
--------------------------------------------------------------------------
origin PING
dest. PONG
--------------------------------------------------------------------------
is also some other traffic. A little bit of salt (random data) is added
with each PING and PONG message, to make sure that long sequences of PING/PONG
messages without any other traffic won't result in known plaintext.
This basically covers everything that is sent over the meta connection by
tinc.