No description
7939ee1283
This adds a new mechanism by which tinc can determine if a node is reachable via UDP. The new mechanism is currently redundant with the PMTU discovery mechanism - that will be fixed in a future commit. Conceptually, the UDP discovery mechanism works similarly to PMTU discovery: it sends UDP probes (of minmtu size, to make sure the tunnel is fully usable), and assumes UDP is usable if it gets replies. It assumes UDP is broken if too much time has passed since the last reply. The big difference with the current PMTU discovery mechanism, however, is that UDP discovery probes are only triggered as part of the packet TX path (through try_tx()). This is quite interesting, because it means tinc will never send UDP pings more often than normal packets, and most importantly, it will automatically stop sending pings as soon as packets stop flowing, thereby nicely reducing network chatter. Of course, there are small drawbacks in some edge cases: for example, if a node only sends one packet every minute to another node, these packets will only be sent over TCP, because the interval between packets is too long for tinc to maintain the UDP tunnel. I consider this a feature, not a bug: I believe it is appropriate to use TCP in scenarios where traffic is negligible, so that we don't pollute the network with pings just to maintain a UDP tunnel that's seeing negligible usage. |
||
|---|---|---|
| bash_completion.d | ||
| doc | ||
| gui | ||
| m4 | ||
| src | ||
| test | ||
| .gitignore | ||
| AUTHORS | ||
| configure.ac | ||
| COPYING | ||
| COPYING.README | ||
| Makefile.am | ||
| NEWS | ||
| README | ||
| README.android | ||
| README.git | ||
| THANKS | ||
This is the README file for tinc version 1.1pre11. Installation instructions may be found in the INSTALL file. tinc is Copyright (C) 1998-2014 by: Ivo Timmermans, Guus Sliepen <guus@tinc-vpn.org>, and others. For a complete list of authors see the AUTHORS file. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. See the file COPYING for more details. This is a pre-release --------------------- Please note that this is NOT a stable release. Until version 1.1.0 is released, please use one of the 1.0.x versions if you need a stable version of tinc. Although tinc 1.1 will be protocol compatible with tinc 1.0.x, the functionality of the tinc program may still change, and the control socket protocol is not fixed yet. Security statement ------------------ This version uses an experimental and unfinished cryptographic protocol. Use it at your own risk. Compatibility ------------- Version 1.1pre11 is compatible with 1.0pre8, 1.0 and later, but not with older versions of tinc. When the ExperimentalProtocol option is used, tinc is still compatible with 1.0.X and 1.1pre11 itself, but not with any other 1.1preX version. Requirements ------------ In order to compile tinc, you will need a GNU C compiler environment. Please ensure you have the latest stable versions of all the required libraries: - OpenSSL (http://www.openssl.org/) version 1.0.0 or later, with support for elliptic curve cryptography (ECC) and Galois counter mode (GCM) enabled. The following libraries are used by default, but can be disabled if necessary: - zlib (http://www.gzip.org/zlib/) - lzo (http://www.oberhumer.com/opensource/lzo/) - ncurses (http://invisible-island.net/ncurses/) - readline (ftp://ftp.gnu.org/pub/gnu/readline/) Features -------- Tinc is a peer-to-peer VPN daemon that supports VPNs with an arbitrary number of nodes. Instead of configuring tunnels, you give tinc the location and public key of a few nodes in the VPN. After making the initial connections to those nodes, tinc will learn about all other nodes on the VPN, and will make connections automatically. When direct connections are not possible, data will be forwarded by intermediate nodes. By default, nodes authenticate each other using 2048 bit RSA (or 521 bit ECDSA*) keys. Traffic is encrypted using Blowfish in CBC mode (or AES-256 in GCM mode*), authenticated using HMAC-SHA1 (or GCM*), and is protected against replay attacks. *) When using the ExperimentalProtocol option. Tinc fully supports IPv6. Tinc can operate in several routing modes. In the default mode, "router", every node is associated with one or more IPv4 and/or IPv6 Subnets. The other two modes, "switch" and "hub", let the tinc daemons work together to form a virtual Ethernet network switch or hub. Normally, when started tinc will detach and run in the background. In a native Windows environment this means tinc will intall itself as a service, which will restart after reboots. To prevent tinc from detaching or running as a service, use the -D option. The status of the VPN can be queried using the "tinc" command, which connects to a running tinc daemon via a control connection. The same tool also makes it easy to start and stop tinc, and to change its configuration.