X-Git-Url: http://www.average.org/gitweb/?p=pdns-pipe-nmc.git;a=blobdiff_plain;f=README.md;h=bac7d26f51eb6a86d4e33f7b1cd7a40d9e52e03d;hp=f5a89d1cbc22708810812beeeea30333aa5bcd06;hb=2a8260d971420eacf29c50fc0136627c05f69470;hpb=5d961f6ab5d028c79dbd84ef7e8e02db55c25e4f diff --git a/README.md b/README.md index f5a89d1..bac7d26 100644 --- a/README.md +++ b/README.md @@ -1,46 +1,152 @@ % Namecoin pipe backend for PowerDNS +There exists a project named +[nmcontrol](https://github.com/namecoin/nmcontrol) to create an +all-in-one tool that can, among other things, act as a DNS server +for the `.bit` zone. There is also a tool, +[NamecoinToBind](https://github.com/namecoin/NamecoinToBind), +for offline conversion of namecoin data into BIND zone file. + +Unlike those, this project is a single-purpose tool acting as a (real +time) bridge between [Namecoin](http://namecoin.info/) and DNS. +It is implemented as a `pipe backend` to +[PowerDNS](https://www.powerdns.com/), which provides stable DNS +frontend, and has simple backend interface. + +## Building + +The program is built as a single executable to be run by PowerDns's +pipe backend. It is written in [Haskell](http://www.haskell.org/). +There is no `cabal` configuration at the moment, so to build it, +simply run + +``` +ghc --make pdns-pipe-nmc ``` -Copyright (c) 2014 Eugene Crosser -This software is provided 'as-is', without any express or implied -warranty. In no event will the authors be held liable for any damages -arising from the use of this software. +and install any missing packages it complains about. -Permission is granted to anyone to use this software for any purpose, -including commercial applications, and to alter it and redistribute it -freely, subject to the following restrictions: +## Installing - 1. The origin of this software must not be misrepresented; you must - not claim that you wrote the original software. If you use this - software in a product, an acknowledgment in the product documentation - would be appreciated but is not required. +In the powerdns configuration, you want to specify `master=yes`. +Enable `pipe` backend by setting `launch=pipe`. +Wherever your pdns package keeps the backend configurations, set +this for the pipe backend: - 2. Altered source versions must be plainly marked as such, and must - not be misrepresented as being the original software. +``` +pipe-command=/path/to/pdns-pipe-nmc +pipe-timeout=10000 +pipe-regex=.bit;.*$ +pipebackend-abi-version=1 ## all versions supported, but extra data ignored +``` - 3. This notice may not be removed or altered from any source - distribution. +Copy `pdns-pipe-nmc` to the place that you've set up as `pipe-command`. +Copy your namecoin cofig file to `/etc/namecoin.conf` and make sure it +is readable by the userid specified in the powerdns config. Entries +recognized in the `/etc/namecoin.conf` file (with default values) are: + +``` +rpcuser= +rpcpassword= +rpchost=localhost +rpcport=8336 ``` ------------------------------------------------------------------------- +They are the parameters needed to contact the `namecoind` server over +its JsonRPC interface. With default installation on `localhost`, you +will only need to specify `rpcpassword`. + +Configure your resolvers to use the PowerDns instance for queries in +the `.bit` zone. This is left as an exercise to the reader. + +## Security Considerations + +Namecoin per se has excellent non-repudiation characteristics. But +once you've converted the data into (non-DNSSEC-protected) DNS +format, all bets are off. If you intend to query your powerdns +instance over public Internet, remember that nothing prevents evil +hackers or ruthless governments from tampering with your queries +and powerdns responses. There are two possible approaches to +mitigation of this problem: + +* Run namecoind and powerdns as close to the consumer as +possible: on the same host, or at least on the same network, and +keep it guarded. +* I did not try it, but it should be possible to use PowerDNS +[Front-signing](http://doc.powerdns.com/html/dnssec-modes.html#dnssec-frontserver), +so the communication will happen over DNSSEC protocol without the +need to keep the signatures in the zone data itself. You probably +would need to create signing key for the PowerDNS instance, and add +the corresponding public key as "trusted" into the configuration of +your resolvers. + +## Status + +Alpha. It is insufficiently tested, and there are loose ends in the +functionality. For example, version in the `SOA` record is bogus. +Some of the the problems are due to incomplete and/or imprecise +[definition of the domain data format](https://wiki.namecoin.info/index.php?title=Domain_Name_Specification) +on the wiki. That said, I am using it to access some of the `.bit` websites +and did not notice anomalies so far. + +Try at your risk. + +## Unsolved problems + +The biggest problem by far is generating meaningful `SOA` records. DNS +infrastructure (including PowerDNS implementation) relies on the "generation" +field of the `SOA` RR when it makes decision to invalidate the cache. So, +if there is zone data in the DNS cache, and a DNS server needs to respond +to a request about an object from that zone, it first checks if the TTL +has expired. If it has not, the server takes the data from the cache. If +it has expired, the server asks the "authoritative source" (which is in +our case the dnamecoin daemon) for the SOA record and compares the +generation count in the received response with the number kept in the +cache. If the "authoritative" SOA does not have a greater generation +count than the cached SOA, DNS server **does not** refresh its cache, +presuming that the data there is still valid. + +So, it is important that the generation count in the SOA record is +incremented every time when the domain object, or any of the object that +it "include"-s or to which it "delegate"-s is changed. + +At present, there is no machanism for that. In most cases, simply +summing the number of entries in `name_history`-s of all domain object +involved in resolution would work, but this approach would produce +wrong result when an "import" entry is removed from a domain, because +in such case the sum would decrease. It would also not notice the +changes in an object "include"-ed in a subdomain, unless complete +recursive resolution of the subdomain tree is enforced for when +SOA record is requested. That would invalidate the reason to have +caching in the first place. + +One possible workaround would be to use some derivative of absolute +time, such as the number of hours elapsed since the epoch, for the +SOA generation count. + +At the time of this writing, `pdns-pipe-nmc` simply reports zero as +the SOA generation count. This leads to stale results until `pdnsd` +is restarted. + +## Getting the Software + +Check the [project homepage](http://www.average.org/pdns-pipe-nmc/). + +### Source + +Git [clone](git://git.average.org/git/pdns-pipe-nmc.git) or +[browse](http://www.average.org/gitweb/?p=pdns-pipe-nmc.git;a=summary), +or use [github mirror](https://github.com/crosser/pdns-pipe-nmc). -## Namecoin pipe backend for PowerDNS +### Binary Executable -There exists a [project](https://github.com/namecoin/nmcontrol) to -create an all-in-one tool that can, among other things, act as a DNS -server for the `.bit` zone. There is also a -[tool](https://github.com/namecoin/NamecoinToBind) for offline -conversion of namecoin data into BIND zone file. +There is a binary built for x86_64 Linux with glibc6: -Unlike that, this project is a single-purpose tool acting as a (real -time) bridge between [Namecoin](https://namecoin.org/) and DNS. -[PowerDNS](https://www.powerdns.com/) provides a stable DNS frontend, -with an easy to implement backend interface, which is used in this -project. +| Executable file | PGP | +|----------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------| +| [pdns-pipe-nmc.linux-glibc6.x86_64.2014-04-20.git-e9bd43f](pdns-pipe-nmc.linux-glibc6.x86_64.2014-04-20.git-e9bd43f) | [sig](pdns-pipe-nmc.linux-glibc6.x86_64.2014-04-20.git-e9bd43f.sig) | -# Status +## Author -Alpha. It does not handle `SRV` records at all, does not support -`delegate` (not to mention `import`), provides bogus version in the -`SOA` record, and is largely untested. Try at your risk. +Eugene Crosser \ +