______  ____________________.
                               /     / /                    |
                              /     . /                     |  R
               ________  ____/___  __/_____   _____         |
         __  __\__    /__\__    /__\__    /__\\__  \__      |  R
          ///   _/   //   _/   //   |/    \\    ._    \     |
          _/    \    \_   \    \_   '     /_    |/    //    |  D
          \_____/_____/___/_____/__________/____/    /_     |
       <---------h7/dS!---- \      . \ -------\\______/     |  A
                             \      \ \                     |
                              \______\ \____________________|

Description

RRDA is a REST API written in Go allowing to perform DNS queries over HTTP, and to get reverse PTR records for both IPv4 and IPv6 addresses. It outputs JSON-encoded DNS responses.

The API allows to specify which name server to query (either recursive or authoritative), and can be used as a foundation to build DNS looking glasses.

RRDA is a recursive acronym for "RRDA REST DNS API".

Requirements

RRDA requires the following Go libraries:

• chi: lightweight, idiomatic and composable router - https://github.com/go-chi/chi
• dns: DNS library in Go - https://github.com/miekg/dns

Installation

Build and install with the go tool, all dependencies will be automatically fetched and compiled:

go build
go install rrda

Usage

By default, RRDA will bind on localhost, port 8080.

USAGE:
  -host string
        Set the server host (default "127.0.0.1")
  -port string
        Set the server port (default "8080")
  -timeout int
        Set the query timeout in ms (default 2000)
  -version
        Display version

Running RRDA at boot time

Systemd unit file

RRDA is bundled with a systemd unit file, see: systemd/rrda.service

Copy the systemd/rrda.service file in /etc/systemd/system and the RRDA binary in /usr/local/sbin.

To launch the daemon at startup, run:

systemctl enable rrda

Making Queries

The following examples assume there is a resolver on localhost listening on port 53.

Getting Resources Records

URL Scheme: http://server:port/resolver:port/domain/querytype

• Example (using an IPv4 resolver): http://127.0.0.1:8080/127.0.0.1:53/example.org/ns
• Example (using an IPv6 resolver): http://127.0.0.1:8080/[::1]:53/example.org/ns

Getting Reverse PTR Records (for both IPv4 and IPv6 addresses)

URL Scheme: http://server:port/resolver:port/x/ip

• Example (IPv4): http://127.0.0.1:8080/127.0.0.1:53/x/193.0.6.139
• Example (IPv6): http://127.0.0.1:8080/127.0.0.1:53/x/2001:67c:2e8:22::c100:68b

Identify a Name Server instance

URL Scheme: http://server:port/resolver:port/id

• Example (using an IPv4 resolver): http://127.0.0.1:8080/127.0.0.1:53/id
• Example (using an IPv6 resolver): http://127.0.0.1:8080/[::1]:53/id

JSONP Support

RRDA supports JSONP callbacks.

• Example: http://127.0.0.1:8080/127.0.0.1:53/example.org/ns?callback=rrda

JSON Output Schema

The output is a JSON object containing the following arrays, representing the appropriate sections of DNS packets:

• question
• answer
• authority (omitted if empty)
• additional (omitted if empty)

Question section

• name
• type
• class

Answer, Authority, Additional sections

• name
• type
• class
• ttl
• rdlength
• rdata

Client Errors

When incorrect user input is entered, the server returns an HTTP 400 Error (Bad Request), along with a JSON-encoded error message.

• Code 401: Input string could not be parsed
• Code 402: Input string is not a well-formed domain name
• Code 403: Input string is not a valid IP address
• Code 404: Invalid DNS query type

Examples

curl http://127.0.0.1:8080/:53/statdns..net/a
{"code":402,"message":"Input string is not a well-formed domain name"}

curl http://127.0.0.1:8080/:53/x/127.0
{"code":403,"message":"Input string is not a valid IP address"}

curl http://127.0.0.1:8080/:53/statdns.net/error
{"code":404,"message":"Invalid DNS query type"}

Server Errors

When the DNS server cannot be reached or returns an error, the server returns an HTTP 500 Error (Internal Server Error), along with a JSON-encoded error message.

• Code 501: DNS server could not be reached
• Code 502: The name server encountered an internal failure while processing this request (SERVFAIL)
• Code 503: Some name that ought to exist, does not exist (NXDOMAIN)
• Code 505: The name server refuses to perform the specified operation for policy or security reasons (REFUSED)

Examples

curl http://127.0.0.1:8080/127.0.0.2:53/statdns.net/a
{"code":501,"message":"DNS server could not be reached"}

curl http://127.0.0.1:8080/:53/lame2.broken-on-purpose.generic-nic.net/soa
{"code":502,"message":"The name server encountered an internal failure while processing this request (SERVFAIL)"}

curl http://127.0.0.1:8080/:53/statdns.nete/a
{"code":503,"message":"Some name that ought to exist, does not exist (NXDOMAIN)"}

curl http://127.0.0.1:8080/:53/lame.broken-on-purpose.generic-nic.net/soa
{"code":505,"message":"The name server refuses to perform the specified operation for policy or security reasons (REFUSED)"}

Sites using RRDA

• StatDNS: Rest DNS API - https://www.statdns.com/api/
• DNS-LG: Multilocation DNS Looking Glass - http://www.dns-lg.com

License

RRDA is released under the BSD 2-Clause license. See LICENSE file for details.

Author

RRDA is developed by Frederic Cambus

• Site: https://www.cambus.net

Resources

Project homepage: https://www.statdns.com

Latest tarball release: https://www.statdns.com/rrda/rrda-1.4.1.tar.gz

GitHub: https://github.com/fcambus/rrda