provided that the entire resulting derived work is distributed
under the terms of a permission notice identical to this one.
- $Id: CONNECTIVITY,v 1.1.2.9 2002/06/21 10:11:10 guus Exp $
-
-1. Problem
+ $Id: CONNECTIVITY,v 1.1.2.10 2002/09/15 22:19:37 guus Exp $
+
+1. Synchronisation
+==================
+
+Each tinc daemon has zero or more connections to other tinc daemons. It will
+try to keep it's own information synchronised with the other tinc daemons. If
+one of it's peers sends information, the tinc daemon will check if it is new
+information. If so, it will update it's own information and forward the new
+information to all the other peers.
+
+This scheme will make sure that after a short amount of time all tinc daemons
+share the same information. It will also almost completely prevent information
+from looping, because "new" information that is already known is ignored and
+not forwarded any further. However, since information can also be deleted
+there's the possibility of a looping sequence of add/delete messages. This is
+resolved by additionaly adding a unique identifier to each broadcasted message.
+Messages are dropped if the same message with that identifier has already been
+seen.
+
+2. Routing
==========
-We have a set of nodes (A, B, C, ...) that are part of the same VPN. They need
-to connect to eachother and form a single graph that satisfies the tree
-property.
-
-There is the possibility that loops are formed, the offending connections must
-be eliminated.
-
-Suppose we start with two smaller graphs that want to form a single larger
-graph. Both graphs consist of three nodes:
-
- A-----B-----C
-
-
-
- D-----E-----F
-
-It is very well possible that A wants to connect to D, and F wants to connect
-to C, both at the same time. The following loop will occur:
-
- A-----B-----C
- | ^
- | |
- v |
- D-----E-----F
-
-The situation described here is totally symmetric, there is no preference to
-one connection over the other. The problem of resolving the loop, maintaining
-consistency and stability is therefore not a trivial one.
-
-What happens when A---D and C---F are connected to eachother? They exchange
-lists of known hosts. A knows of B and C, and D knows of E and F. The protocol
-defines ADD_HOST messages, from now on we will say that "node X sends and
-ADD_HOST(Y) to Z".
-
-There are two possible scenarios: either both A---D and C---F finish
-authentication at the same time, or A---D finishes first, so that ADD_HOST
-messages will reach C and F before they finish authentication.
-
-1.1 A---D finishes first
-------------------------
-
-After A---D authentication finishes the following actions are taken:
-
- 1 A sends ADD_HOST(B) to D
- A sends ADD_HOST(C) to D
- D sends ADD_HOST(E) to A
- D sends ADD_HOST(F) to A
-
- 2 A sends ADD_HOST(D) to B
- A receives ADD_HOST(E) from D:
- A sends ADD_HOST(E) to B
- A receives ADD_HOST(F) from D:
- A sends ADD_HOST(F) to B
- D sends ADD_HOST(A) to E
- D receives ADD_HOST(B) from A:
- D sends ADD_HOST(B) to E
- D receives ADD_HOST(C) from A:
- D sends ADD_HOST(C) to E
-
- 3 B receives ADD_HOST(D) from A,
- B sends ADD_HOST(D) to C
- B receives ADD_HOST(E) from A:
- B sends ADD_HOST(E) to C
- B receives ADD_HOST(F) from A:
- B sends ADD_HOST(F) to C
- E receives ADD_HOST(A) from D:
- E sends ADD_HOST(A) to F
- E receives ADD_HOST(B) from D:
- E sends ADD_HOST(B) to F
- E receives ADD_HOST(C) from D:
- E sends ADD_HOST(C) to F
-
- 4 C receives ADD_HOST(D) from B.
- C receives ADD_HOST(E) from B.
- C receives ADD_HOST(F) from B.
- F receives ADD_HOST(A) from E.
- F receives ADD_HOST(B) from E.
- F receives ADD_HOST(C) from E.
-
-Then C---F authentication finishes, the following actions are taken:
-
- 1 C notes that F is already known:
- Connection is closed.
- F notes that C is already known:
- Connection is closed.
-
-1.2 Both A---D and C---F finish at the same time.
--------------------------------------------------
-
- 1 A sends ADD_HOST(B) to D
- A sends ADD_HOST(C) to D
- D sends ADD_HOST(E) to A
- D sends ADD_HOST(F) to A
-
- C sends ADD_HOST(A) to F
- C sends ADD_HOST(B) to F
- F sends ADD_HOST(D) to C
- F sends ADD_HOST(E) to C
-
- 2 A sends ADD_HOST(D) to B
- A receives ADD_HOST(E) from D:
- A sends ADD_HOST(E) to B
- A receives ADD_HOST(F) from D:
- A sends ADD_HOST(F) to B
- D sends ADD_HOST(A) to E
- D receives ADD_HOST(B) from A:
- D sends ADD_HOST(B) to E
- D receives ADD_HOST(C) from A:
- D sends ADD_HOST(C) to E
-
- C sends ADD_HOST(F) to B
- C receives ADD_HOST(D) from F:
- A sends ADD_HOST(D) to B
- C receives ADD_HOST(E) from F:
- A sends ADD_HOST(E) to B
- F sends ADD_HOSTS(C) to E
- F receives ADD_HOST(A) from C:
- D sends ADD_HOST(A) to E
- F receives ADD_HOST(B) from C:
- D sends ADD_HOST(B) to E
-
- 3 B receives ADD_HOST(D) from A,
- B sends ADD_HOST(D) to C
- B receives ADD_HOST(E) from A:
- B sends ADD_HOST(E) to C
- B receives ADD_HOST(F) from A:
- B sends ADD_HOST(F) to C
- E receives ADD_HOST(A) from D:
- E sends ADD_HOST(A) to F
- E receives ADD_HOST(B) from D:
- E sends ADD_HOST(B) to F
- E receives ADD_HOST(C) from D:
- E sends ADD_HOST(C) to F
-
- B receives ADD_HOST(F) from C, and notes that is is already known:
- <insert solution here>
- B receives ADD_HOST(D) from C, and notes that is is already known:
- <insert solution here>
- B receives ADD_HOST(E) from C, and notes that is is already known:
- <insert solution here>
- E receives ADD_HOST(C) from F, and notes that is is already known:
- <insert solution here>
- E receives ADD_HOST(A) from F, and notes that is is already known:
- <insert solution here>
- E receives ADD_HOST(B) from F, and notes that is is already known:
- <insert solution here>
-
- 4 A receives ADD_HOST(D) from B, and notes that it is already known:
- <insert solution here>
- A receives ADD_HOST(E) from B, and notes that it is already known:
- <insert solution here>
- A receives ADD_HOST(F) from B, and notes that it is already known:
- <insert solution here>
- F receives ADD_HOST(A) from E, and notes that it is already known:
- <insert solution here>
- F receives ADD_HOST(B) from E, and notes that it is already known:
- <insert solution here>
- F receives ADD_HOST(B) from E, and notes that it is already known:
- <insert solution here>
-
- ...
-
-1.2.1 Augmenting ADD_HOST
--------------------------
-
-A solution would be to augment ADD_HOST with an extra parameter, the nexthop of
-the added host:
-
- 3 B receives ADD_HOST(D,A) from A,
- B sends ADD_HOST(D,A) to C
- B receives ADD_HOST(E,D) from A:
- B sends ADD_HOST(E,D) to C
- B receives ADD_HOST(F,E) from A:
- B sends ADD_HOST(F,E) to C
- E receives ADD_HOST(A,D) from D:
- E sends ADD_HOST(A,D) to F
- E receives ADD_HOST(B,A) from D:
- E sends ADD_HOST(B,A) to F
- E receives ADD_HOST(C,B) from D:
- E sends ADD_HOST(C,B) to F
-
- B receives ADD_HOST(F,C) from C, and notes that F is already known:
- <insert solution here>
- B receives ADD_HOST(D,E) from C, and notes that D is already known:
- <insert solution here>
- B receives ADD_HOST(E,F) from C, and notes that E is already known:
- <insert solution here>
- E receives ADD_HOST(C,F) from F, and notes that C is already known:
- <insert solution here>
- E receives ADD_HOST(A,B) from F, and notes that A is already known:
- <insert solution here>
- E receives ADD_HOST(B,C) from F, and notes that B is already known:
- <insert solution here>
-
-So, B and E have to make a choice. Which ADD_HOST is going to win? Fortunately,
-since the ADD_HOST messages are augmented, they have an extra piece of
-information they can use to decide in a deterministic way which one is going to
-win. For example, B got ADD_HOST(F,E) and ADD_HOST(F,C). Since "E" > "C", it
-could let ADD_HOST(F,E) win.
-
- B receives ADD_HOST(F,C) from C, and notes that F is already known:
- since "C" < "E", B ignores ADD_HOST(F,E)
- B sends ADD_HOST(F,C) to A
- ...
- E receives ADD_HOST(C,F) from F, and notes that C is already known:
- since "F" > "B", E removes the ADD_HOST(C,B) in favour of the new one
- E sends ADD_HOST(C,F) to D
-
- 4 A receives ADD_HOST(F,E) from B, and notes that F is already known:
- since "E" < "D", A ignores ADD_HOST(F,D).
- ...
- D receives ADD_HOST(C,F) from E, and notes that C is already known:
- since "F" > "B", D removes the ADD_HOST(C,B),
- closes the connection with C, in favour of the new one.
-
-Ok, time to forget this crap.
-
-1.2.2
------
-
-The problem with the current ADD/DEL_HOST technique is that each host only
-knows the general direction in which to send packets for the other hosts. It
-really doesn't know much about the true topology of the network, only about
-it's direct neighbours. With so little information each host cannot make a
-certain decision which it knows for sure all the others will decide too.
-
-Let's do something totally different. Instead of notifying every host of the
-addition of a new host, which is represented by a vertex in a graph, lets send
-out notifications of new connections, which are the edges in a graph. This is
-rather cheap, since our graphs are (almost) spanning trees, there is
-approximately one edge for each vertex in the graph, so we don't need to send
-more messages. Furthermore, an edge is characterized by two vertices, so we
-only send a fixed amount of extra information. The size/complexity of the
-problem therefore does not increase much.
-
-What is the advantage of notifying each vertex of new edges instead of new
-vertices? Well, all the vertices now know exactly which connections are made
-between each host. This was not known with the former schemes.
-
-Ok back to our problem:
-
- A-----B-----C
-
-
-
- D-----E-----F
-
-Edges are undirected, and are characterised by the vertices it connects, sorted
-alphabetically, so the edges in the two graphs are:
-
-(A,B), (B,C), (D,E) and (E,F).
-
-So again we have that A wants to connect to D, and F wants to connect to C,
-both at the same time. The following loop will occur:
-
- A-----B-----C
- | ^
- | |
- v |
- D-----E-----F
-
-Instead of sending ADD_HOSTs, lets assume the hosts send ADD_EDGEs. So, after
-making the connections:
-
- 1 A sends ADD_EDGE(A,D) to B
- A sends ADD_EDGE(A,B) to D
- A sends ADD_EDGE(B,C) to D
- D sends ADD_EDGE(A,D) to E
- D sends ADD_EDGE(D,E) to A
- D sends ADD_EDGE(E,F) to A
-
- C sends ADD_EDGE(C,F) to B
- C sends ADD_EDGE(A,B) to F
- C sends ADD_EDGE(B,C) to F
- F sends ADD_EDGE(C,F) to E
- F sends ADD_EDGE(D,E) to C
- F sends ADD_EDGE(E,F) to C
-
- 2 B receives ADD_EDGE(A,D) from A:
- B sends ADD_EDGE(A,D) to C
- B receives ADD_EDGE(D,E) from A:
- B sends ADD_EDGE(D,E) to C
- B receives ADD_EDGE(E,F) from A:
- B sends ADD_EDGE(E,F) to C
- ...
-
- B receives ADD_EDGE(C,F) from C, notes that both C and F are already known,
- but that the edge (C,F) was not known, so a loop has been created:
- <resolve loop here>
-
-Ok, how to resolve the loop? Remeber, we want to do that in such a way that it
-is consistent with the way all the other hosts resolve the loop. Here is the
-things B does when it notices that a loop is going to be formed:
-
- B performs a Breadth First Search from the first element of the list of all
- known hosts sorted alfabetically, in this case A, and thereby finds a
- spanning tree. (This might later be changed into a minimum spanning tree
- alhorithm, but the key point here is that all hosts do this with exactly the
- same starting parameters.) All known edges that are not in the spanning tree
- are marked inactive.
-
-An edge marked inactive does not mean anything, unless this edge is connected
-to B itself. In that case, B will stop sending messages over that edge. B might
-consider closing this edge, but this is not really needed. Keeping it means no
-DEL_EDGE has to be sent for it, and if another edge is removed (which will
-quite certainly split the graph if it's a spanning tree), this edge might be
-reactivated, without the need of sending a new ADD_EDGE for it. On the other
-hand, we mustn't keep to many inactive edges, because we want to keep the
-number of known edges linear to the number of hosts (otherwise the size of the
-problem will grow quadratically).
-
-So, since B didn't deactivate one of it's own edges, it forwards the
-ADD_EDGE(C,F) to A, which also does a BFS, and so on, until it reaches F. F of
-course also does a BFS, notes that is is one of it's own edges. It deactivates
-the edge (C,F), and consequently will not forward the ADD_EDGE(C,F) to C
-anymore. In the mean time, C got messages from B which will make C do the same.
-
-Ok, suppose a DEL_EDGE was sent, and it means an inactive edge has to be
-reactivated. The vertices connected by that edge must exchange their entire
-knowledge of edges again, because in the mean time other messages could have
-been sent, which were not properly forwarded. Take this example:
-
- X C-----D
- | | |
- | | |
- v | |
- A-----B- - -E
+Every node tells it's peers to which other peers it is connected. This way
+every node will eventually know every connection every node has on the VPN.
+Each node will use graph algorithms to determine if other nodes are reachable or not and
+what the best route is to other nodes.
-The edge (B,E) is inactive. X is trying to make a new connection with A. A
-sends an ADD_EDGE(A,X) to B, which forwards it to C. At that time, the
-connection between C and D goes down, so C sends a DEL_EDGE(C,D) to B, and D
-sends a DEL_EDGE(C,D) to E. If we just allow (B,E) to be reactivated again
-without anything else, then E and D will never have received the ADD_EDGE(A,X).
-So, B and E have to exchange edges again, and propagate them to the hosts they
-already know.
+Because all nodes share the same information, using a deterministic algorithm
+each node will calculate the same minimum spanning tree for the entire VPN.
+The MST will be used to send broadcast VPN packets.
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
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
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.
provided that the entire resulting derived work is distributed
under the terms of a permission notice identical to this one.
- $Id: SECURITY2,v 1.1.2.3 2002/06/21 10:11:10 guus Exp $
+ $Id: SECURITY2,v 1.1.2.4 2002/09/15 22:19:37 guus Exp $
Proposed new authentication scheme
----------------------------------
After the correct challenge replies are recieved, both ends have proved
their identity. Further information is exchanged.
-client ACK 655 12.23.34.45 123 0
- | | | +-> options
- | | +----> estimated weight
- | +------------> IP address of server as seen by client
- +--------------------> UDP port of client
-
-server ACK 655 21.32.43.54 321 0
- | | | +-> options
- | | +----> estimated weight
- | +------------> IP address of client as seen by server
- +--------------------> UDP port of server
+client ACK 655 123 0
+ | | +-> options
+ | +----> estimated weight
+ +--------> listening port of client
+
+server ACK 655 321 0
+ | | +-> options
+ | +----> estimated weight
+ +--------> listening port of server
--------------------------------------------------------------------------
This new scheme has several improvements, both in efficiency and security.
# but for ethertap and FreeBSD this is tap0, tap1, tap2 etcetera,
# for Solaris and OpenBSD it is tun0, tun1, etcetera.
-# Set hardware ethernet address (required!)
+# Set hardware ethernet address, needed on Linux when in router mode
ifconfig $INTERFACE hw ether fe:fd:0:0:0:0
# Give it the right ip and netmask. Remember, the subnet of the
# tap device must be larger than that of the individual Subnets
# as defined in the host configuration file!
-ifconfig $INTERFACE 192.168.1.1 netmask 255.255.0.0 -arp
+ifconfig $INTERFACE 192.168.1.1 netmask 255.255.0.0
+
+# Disable ARP, needed on Linux when in router mode
+ifconfig $INTERFACE -arp
# The tap device tinc will use. Required.
# Default is /dev/tap0 for ethertap or FreeBSD,
# /dev/tun0 for Solaris and OpenBSD,
-# and /dev/misc/net/tun for Linux tun/tap device.
-Device = /dev/misc/net/tun
+# and /dev/net/tun for Linux tun/tap device.
+Device = /dev/net/tun
# The file in which the private key for this host is stored. Required.
PrivateKeyFile = /etc/tinc/example/rsa_key.priv
.Nm tinc
won't try to connect to other daemons at all,
and will instead just listen for incoming connections.
-.It Va Device Li = Ar device Po /dev/tap0 or /dev/misc/net/tun Pc
+.It Va Device Li = Ar device Po /dev/tap0 or /dev/net/tun Pc
The virtual network device to use.
.Nm tinc
will automatically detect what kind of device it is.
\input texinfo @c -*-texinfo-*-
-@c $Id: tinc.texi,v 1.8.4.31 2002/07/16 13:18:27 guus Exp $
+@c $Id: tinc.texi,v 1.8.4.32 2002/09/15 22:19:37 guus Exp $
@c %**start of header
@setfilename tinc.info
@settitle tinc Manual
<ivo@@o2w.nl>, Guus Sliepen <guus@@sliepen.eu.org> and
Wessel Dankers <wsl@@nl.linux.org>.
-$Id: tinc.texi,v 1.8.4.31 2002/07/16 13:18:27 guus Exp $
+$Id: tinc.texi,v 1.8.4.32 2002/09/15 22:19:37 guus Exp $
Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
<ivo@@o2w.nl>, Guus Sliepen <guus@@sliepen.eu.org> and
Wessel Dankers <wsl@@nl.linux.org>.
-$Id: tinc.texi,v 1.8.4.31 2002/07/16 13:18:27 guus Exp $
+$Id: tinc.texi,v 1.8.4.32 2002/09/15 22:19:37 guus Exp $
Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
@cindex requirements
@cindex libraries
Before you can configure or build tinc, you need to have the OpenSSL
-library installed on your system. If you try to configure tinc without
-having installed it, configure will give you an error message, and stop.
+and zlib libraries installed on your system. If you try to configure tinc without
+having them installed, configure will give you an error message, and stop.
@menu
* OpenSSL::
tinc comes in a convenient autoconf/automake package, which you can just
treat the same as any other package. Which is just untar it, type
-`configure' and then `make'.
+`./configure' and then `make'.
More detailed instructions are in the file @file{INSTALL}, which is
included in the source distribution.
If you use Linux, and you run the new 2.4 kernel using the devfs filesystem,
then the tun/tap device will probably be automatically generated as
-@file{/dev/misc/net/tun}.
+@file{/dev/net/tun}.
Unlike the ethertap device, you do not need multiple device files if
you are planning to run multiple tinc daemons.
@section How connections work
When tinc starts up, it parses the command-line options and then
-reads in the configuration file.
-If it sees a `ConnectTo' value pointing to another tinc daemon in the file,
-it will try to connect to that other one.
+reads in the configuration file tinc.conf.
+If it sees one or more `ConnectTo' values pointing to other tinc daemons in that file,
+it will try to connect to those other daemons.
Whether this succeeds or not and whether `ConnectTo' is specified or not,
tinc will listen for incoming connection from other deamons.
If you did specify a `ConnectTo' value and the other side is not responding,
This means that once started, tinc will stay running until you tell it to stop,
and failures to connect to other tinc daemons will not stop your tinc daemon
for trying again later.
-This means you don't have to intervene if there are any network problems.
+This means you don't have to intervene if there are temporary network problems.
@cindex client
@cindex server
There is no real distinction between a server and a client in tinc.
If you wish, you can view a tinc daemon without a `ConnectTo' value as a server,
and one which does specify such a value as a client.
-It does not matter if two tinc daemons have a `ConnectTo' value pointing to eachother however.
+It does not matter if two tinc daemons have a `ConnectTo' value pointing to each other however.
@c ==================================================================
and will instead just listen for incoming connections.
@cindex Device
-@item @strong{Device = <device>} (/dev/tap0 or /dev/misc/net/tun)
+@item @strong{Device = <device>} (/dev/tap0 or /dev/net/tun)
The virtual network device to use. Note that you can only use one device per
daemon. See also @ref{Device files}.
@cindex Port
@item Port = <port> (655)
-Connect to the upstream host (given with the ConnectTo directive) on
-port port. port may be given in decimal (default), octal (when preceded
-by a single zero) o hexadecimal (prefixed with 0x). port is the port
-number for both the UDP and the TCP (meta) connections.
+This is the port this tinc daemon listens on.
+You can use decimal portnumbers or symbolic names (as listed in /etc/services).
@cindex PublicKey
@item PublicKey = <key> [obsolete]
@example
Name = BranchD
ConnectTo = BranchC
-Device = /dev/misc/net/tun
+Device = /dev/net/tun
PrivateKeyFile = /etc/tinc/company/rsa_key.priv
@end example
Besides the settings in the configuration file, tinc also accepts some
command line options.
-This list is a longer version of that in the manpage. The latter is
-generated automatically, so may be more up-to-date.
-
@cindex command line
@cindex runtime options
@cindex options
Don't fork and detach.
This will also disable the automatic restart mechanism for fatal errors.
+@item -L, --mlock
+Lock tinc into main memory.
+This will prevent sensitive data like shared private keys to be written to the system swap files/partitions.
+
@item --version
Output version information and exit.
@item You forgot to compile `Netlink device emulation' in the kernel.
@end itemize
-@item Can't write to /dev/misc/net/tun: No such device
+@item Can't write to /dev/net/tun: No such device
@itemize
@item You forgot to `modprobe tun'.
@item Network doesn't work, syslog shows only packets of length 46
-@cindex arp
-@example
-Jan 1 12:00:00 host tinc.net[1234]: Read packet of length 46 from tap device
-Jan 1 12:00:00 host tinc.net[1234]: Trying to look up 0.0.192.168 in connection list failed!
-@end example
-@itemize
-@item Add the `ifconfig $INTERFACE -arp' to tinc-up.
-@end itemize
-
@item Network address and prefix length do not match!
@itemize
@itemize
@item You must specify the complete pathname.
Specifying a relative path does not make sense here. tinc changes its
-directory to / when starting (to avoid keeping a mount point busy); and
-even if we built in a default directory to look for these files, the key
-files are bound to be in a different directory.
+directory to / when starting (to avoid keeping a mount point busy).
@end itemize
@end table
Since the latter modes only depend on the link layer information,
any protocol that runs over Ethernet is supported (for instance IPX and Appletalk).
-After the destination has been determined, a sequence number will be added to the packet.
-The packet will then be encrypted and a message authentication
-code will be appended.
+After the destination has been determined,
+the packet will be compressed (optionally),
+a sequence number will be added to the packet,
+the packet will then be encrypted
+and a message authentication code will be appended.
@cindex encapsulating
@cindex UDP
address must match that of the virtual network interface.
If tinc is in it's default routing mode, ARP does not work, so the correct destination MAC cannot be set
by the sending daemons.
-tinc solves this by always overwriting the
-destination MAC address with fe:fd:0:0:0:0. That is also the reason why you must
-set the MAC address of your tap interface to that address.
+tinc solves this by letting the receiving end detect the MAC address
+and overwriting the destination MAC address of the received packet.
+However, the MAC address of the network interface at the receiver might not always be known to tinc.
+That is the reason why you should set the MAC address of your tap interface to that address
+when in routing mode.
+
+In switch or hub modes ARP does work so the sender already knows the correct destination MAC address.
+In those modes every interface should have a unique MAC address, so make sure they are not the same.
@c ==================================================================
@node The meta-connection, , The UDP tunnel, The connection
@subsection The meta-connection
-Having only an UDP connection available is not enough. Though suitable
+Having only a UDP connection available is not enough. Though suitable
for transmitting data, we want to be able to reliably send other
information, such as routing and session key information to somebody.
side. Each request has a unique number and several parameters. All
requests are represented in the standard ASCII character set. It is
possible to use tools such as telnet or netcat to connect to a tinc
-daemon and to read and write requests by hand, provided that one
+daemon started with the --bypass-security option
+and to read and write requests by hand, provided that one
understands the numeric codes sent.
The authentication scheme is described in @ref{Authentication protocol}. After a
@example
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
--------------------------------------------------------------------------
@end example
+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.
+
@cindex DEL_EDGE
+@cindex DEL_SUBNET
+@example
+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
+------------------------------------------------------------------
+@end example
+
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.
+@cindex REQ_KEY
+@cindex ANS_KEY
+@cindex KEY_CHANGED
+@example
+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
+--------------------------------------------------------------------------
+@end example
+
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
other daemon. Instead, if a daemon needs a key it sends a request for it
via the meta connection of the nearest hop in the direction of the
-destination. If any hop on the way has already learned the key, it will
-act as a proxy and forward its copy back to the requester.
+destination.
-@cindex REQ_KEY
-@cindex ANS_KEY
-@cindex KEY_CHANGED
+@cindex PING
+@cindex PONG
@example
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
--------------------------------------------------------------------------
@end example
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.
-@cindex PING
-@cindex PONG
-@example
-daemon message
---------------------------------------------------------------------------
-origin PING
-dest. PONG
---------------------------------------------------------------------------
-@end example
-
This basically covers what is sent over the meta connection by
tinc.
After the correct challenge replies are received, both ends have proved
their identity. Further information is exchanged.
-client ACK 655 12.23.34.45 123 0
- | | | +-> options
- | | +----> estimated weight
- | +------------> IP address of server as seen by client
- +--------------------> UDP port of client
-
-server ACK 655 21.32.43.54 321 0
- | | | +-> options
- | | +----> estimated weight
- | +------------> IP address of client as seen by server
- +--------------------> UDP port of server
+client ACK 655 123 0
+ | | +-> options
+ | +----> estimated weight
+ +--------> listening port of client
+
+server ACK 655 321 0
+ | | +-> options
+ | +----> estimated weight
+ +--------> listening port of server
--------------------------------------------------------------------------
@end example
Encrypted with symmetric cipher
@end example
-So, the entire VPN packet is encrypted using a symmetric cipher. A 32 bits
-sequence number is added in front of the actual VPN packet, to act as a unique
+So, the entire VPN packet is encrypted using a symmetric cipher, including a 32 bits
+sequence number that is added in front of the actual VPN packet, to act as a unique
IV for each packet and to prevent replay attacks. A message authentication code
is added to the UDP packet to prevent alteration of packets. By default the
first 4 bytes of the digest are used for this, but this can be changed using
this server is located in the Netherlands.
@cindex IRC
-We have an IRC channel on the Open Projects IRC network. Connect to
-@uref{http://openprojects.nu/services/irc.html, irc.openprojects.net},
+We have an IRC channel on the FreeNode IRC network. Connect to
+@uref{http://www.freenode.net/, irc.freenode.net}
and join channel #tinc.
@table @asis
@item Ivo Timmermans (zarq) (@email{ivo@@o2w.nl})
-Main coder/hacker and maintainer of the package.
-
@item Guus Sliepen (guus) (@email{guus@@sliepen.eu.org})
-Originator of it all, co-author.
-
-@item Wessel Dankers (Ubiq) (@email{wsl@@nl.linux.org})
-For the name `tinc' and various suggestions.
-
@end table
We have received a lot of valuable input from users. With their help,
.It Fl D, -no-detach
Don't fork and detach.
This will also disable the automatic restart mechanism for fatal errors.
+.It Fl L, -mlock
+Lock tinc into main memory.
+This will prevent sensitive data like shared private keys to be written to the system swap files/partitions.
.It Fl -version
Output version information and exit.
.El
projects / oweals / tinc.git / commitdiff