https://github.com/defuse/dnsfs

Host files with DNS
https://github.com/defuse/dnsfs

Last synced: about 1 year ago
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Host files with DNS

• Host: GitHub
• URL: https://github.com/defuse/dnsfs
• Owner: defuse
• Created: 2014-03-30T16:50:01.000Z (about 12 years ago)
• Default Branch: master
• Last Pushed: 2016-03-01T16:48:54.000Z (over 10 years ago)
• Last Synced: 2025-02-03T14:52:02.286Z (over 1 year ago)
• Language: Ruby
• Size: 543 KB
• Stars: 32
• Watchers: 5
• Forks: 5
• Open Issues: 1
• Metadata Files:
  • Readme: README.md

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README

          
dnsfs

=====

This is a script for hosting and downloading a static set of files over DNS

*without using a custom DNS server*. If you give `dnsfs.rb` a path to

a directory, it will create BIND-compatible TXT entries for hosting the files

inside. If you give `dnsfs.rb` a domain name, it will show you the list of

hosted files and ask which one you want to download.

How fast is it? I downloaded a 568K file from my nameserver in 293 seconds... so

about 1981 bytes/second. Of course it depends on the RTT, and it can probably be

sped up a lot by sending requests in parallel (this script doesn't).

NOTE: I'm pretty sure something like this has been done before... I just wanted

to write it myself and couldn't find the reference. Please let me know of

similar things!

**Related Work**

- http://www.aldeid.com/wiki/File-transfer-via-DNS

Examples

========

Downloading

-----------

Note: Intermediate nameservers may cache your requests. Please be respectful and

query the authoratative nameserver directly using the `--nameserver` option!

    $ ruby dnsfs.rb --download --nameserver dnsfs.defuse.ca dnsfs.defuse.ca

    1. manifesto.txt (size: 3880 bytes)

    2. longcat.jpg (size: 580516 bytes)

    Which one?

    1

    .....................

    File written to /tmp/manifesto.txt.

Generating

----------

    $ ruby dnsfs.rb --generate test

    f1info.dnsfs IN TXT "Name: foo.txt / Size: 31"

    f1p1.dnsfs IN TXT "VGhpcyBpcyAKYSBmaWxlCm5hbWVkCmZvby50eHQhCg=="

    f1p2.dnsfs IN TXT "~EOF~"

    f2info.dnsfs IN TXT "Name: bar.txt / Size: 558"

    f2p1.dnsfs IN TXT "VGhpcyBpcyAKYSBmaWxlCm5hbWVkCmJhci50eHQhClRoaXMgaXMgCmEgZmlsZQpuYW1lZApiYXIudHh0IQpUaGlzIGlzIAphIGZpbGUKbmFtZWQKYmFyLnR4dCEKVGhpcyBpcyAKYSBmaWxlCm5hbWVkCmJhci50eHQhClRoaXMgaXMgCmEgZmlsZQpuYW1lZApiYXIudHh0IQpUaGlzIGlzIAphIGZpbGUKbmFtZWQKYmFyLnR4dCEKVGhp"

    f2p2.dnsfs IN TXT "cyBpcyAKYSBmaWxlCm5hbWVkCmJhci50eHQhClRoaXMgaXMgCmEgZmlsZQpuYW1lZApiYXIudHh0IQpUaGlzIGlzIAphIGZpbGUKbmFtZWQKYmFyLnR4dCEKVGhpcyBpcyAKYSBmaWxlCm5hbWVkCmJhci50eHQhClRoaXMgaXMgCmEgZmlsZQpuYW1lZApiYXIudHh0IQpUaGlzIGlzIAphIGZpbGUKbmFtZWQKYmFyLnR4dCEKVGhpcyBp"

    f2p3.dnsfs IN TXT "cyAKYSBmaWxlCm5hbWVkCmJhci50eHQhClRoaXMgaXMgCmEgZmlsZQpuYW1lZApiYXIudHh0IQpUaGlzIGlzIAphIGZpbGUKbmFtZWQKYmFyLnR4dCEKVGhpcyBpcyAKYSBmaWxlCm5hbWVkCmJhci50eHQhClRoaXMgaXMgCmEgZmlsZQpuYW1lZApiYXIudHh0IQpUaGlzIGlzIAphIGZpbGUKbmFtZWQKYmFyLnR4dCEK"

    f2p4.dnsfs IN TXT "~EOF~"

    f3info.dnsfs IN TXT "~EOL~"

Downloading Without Ruby

------------------------

The naming convention makes it easy to download a file with a standard `/bin/sh`

command:

    for i in `seq 21`; do host -t TXT f1p$i.dnsfs.defuse.ca|cut -d '"' -f 2|base64 --decode; done|less

Alternatively, using `dig`:

    for i in `seq 21`; do dig f1p$i.dnsfs.defuse.ca TXT|grep TXT|grep '"'|cut -d '"' -f 2|base64 --decode; done|less

All you have to do is replace `f1` with the file number you want and `seq 21`

with the number of parts in the file (the ceiling of the file size divided by

189).

How It Works

============

For each file K in 1..N, there are a set of TXT entries:

- fKinfo: File K's name and size.

- fN+1info: End of list marker: `~EOL~`

- fKpP: Part *P* of file *K* base64-encoded. Last one is `~EOF~`.