godns

GODNS

A simple and fast dns cache server written by go. fork from kenshinx/godns.

Similar to dnsmasq, but supports some difference features:

• Keep hosts records in redis and the local file /etc/hosts
• Auto-Reloads when hosts configuration is changed. (Yes, dnsmasq needs to be reloaded)

Installation & Running

1. Install

   $ go get github.com/kenshinx/godns

2. Build

   $ cd $GOPATH/src/github.com/kenshinx/godns $ go build -o godns

3. Running

   $ sudo ./godns -c ./etc/godns.conf

4. Test

   $ dig www.github.com @127.0.0.1

   $ dig @101.4.1.17 wiki.bjca
   
   ; <<>> DiG 9.10.6 <<>> @101.4.1.17 wiki.bjca
   ; (1 server found)
   ;; global options: +cmd
   ;; Got answer:
   ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 1578
   ;; flags: qr rd; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 0
   ;; WARNING: recursion requested but not available
   
   ;; QUESTION SECTION:
   ;wiki.bjca.			IN	A
   
   ;; ANSWER SECTION:
   wiki.bjca.		600	IN	A	192.168.131.51
   
   ;; Query time: 4 msec
   ;; SERVER: 101.4.1.17#53(101.4.1.17)
   ;; WHEN: Mon Jul 25 16:36:20 CST 2022
   ;; MSG SIZE  rcvd: 52
   

Use godns

$ sudo vi /etc/resolv.conf
nameserver #the ip of godns running

Configuration

All the configuration in godns.conf is a TOML format config file. More about Toml :https://github.com/mojombo/toml

resolv.conf

Upstream server can be configured by changing file from somewhere other than "/etc/resolv.conf"

[resolv]
resolv-file = "/etc/resolv.conf"

If multiple namerservers are set in resolv.conf, the upsteam server will try in a top to bottom order

server-list-file

Domain-specific nameservers configuration, formatting keep compatible with Dnsmasq.

server=/google.com/8.8.8.8

More cases please refererence dnsmasq-china-list

cache

Only the local memory storage backend is currently implemented. The redis backend is in the todo list

[cache]
backend = "memory"
expire = 600  # default expire time 10 minutes
maxcount = 100000

hosts

Force resolve domain to assigned ip, support two types hosts configuration:

• locale hosts file
• remote redis hosts

hosts file

can be assigned at godns.conf,default : /etc/hosts

[hosts]
host-file = "/etc/hosts"

Hosts file format is described in linux man pages. More than that , *. wildcard is supported additional.

redis hosts

This is a special requirment in our system. Must maintain a global hosts configuration, and support update the host records from other remote server. Therefore, while "redis-hosts" be enabled, will query the redis db when each dns request is reached.

The hosts record is organized with redis hash map. and the key of the map is configured.

[hosts]
redis-key = "godns:hosts"

Insert hosts records into redis

redis > hset godns:hosts www.test.com 1.1.1.1

Compared with file-backend records, redis-backend hosts support multiple A entries.

redis > hset godns:hosts www.test.com 1.1.1.1,2.2.2.2

Benchmark

Debug close

$ go test -bench=.

testing: warning: no tests to run
PASS
BenchmarkDig-8     50000             57945 ns/op
ok      _/usr/home/keqiang/godns        3.259s

The result : 15342 queries/per second

The test environment:

CentOS release 6.4

• CPU: Intel Xeon 2.40GHZ 4 cores

• MEM: 46G

Web console

Joke: A web console for godns

https://github.com/kenshinx/joke

screenshot

Deployment

Deployment in productive supervisord highly recommended.

[program:godns]
command=/usr/local/bin/godns -c /etc/godns.conf
autostart=true
autorestart=true
user=root
stdout_logfile_maxbytes = 50MB
stdoiut_logfile_backups = 20
stdout_logfile = /var/log/godns.log

TODO

• The redis cache backend
• Update ttl

LICENSE

godns is under the MIT license. See the LICENSE file for details.

demo

% dig a.cn @127.0.0.1 -p5301

; <<>> DiG 9.10.6 <<>> a.cn @127.0.0.1 -p5301
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 64638
;; flags: qr rd; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 0
;; WARNING: recursion requested but not available

;; QUESTION SECTION:
;a.cn.                          IN      A

;; ANSWER SECTION:
a.cn.                   600     IN      A       192.168.1.1
a.cn.                   600     IN      A       192.168.1.2

;; Query time: 0 msec
;; SERVER: 127.0.0.1#5301(127.0.0.1)
;; WHEN: Mon Sep 19 13:07:32 CST 2022
;; MSG SIZE  rcvd: 62

bingoobjca@bingoobjcadeMacBook-Pro godns %