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feat: add gh-actions support

This commit is contained in:
Louis Brunner 2021-09-07 20:12:37 +01:00
parent cef21c7bc3
commit ec0945c1ed
3 changed files with 149 additions and 4 deletions

67
.github/workflows/build.yml vendored Normal file
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@ -0,0 +1,67 @@
name: Build
on: [push, pull_request]
jobs:
test:
strategy:
matrix:
go-version: [1.17.x]
os: [ubuntu-latest]
runs-on: ${{ matrix.os }}
steps:
- name: Install Go
uses: actions/setup-go@v2
with:
go-version: ${{ matrix.go-version }}
- uses: actions/checkout@v2
- uses: actions/cache@v2
with:
path: ~/go/pkg/mod
key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}
restore-keys: |
${{ runner.os }}-go-
- name: Vet
run: go vet ./...
- name: Test
run: go test -v ./...
- name: Build
run: go build -v ./...
build:
needs: test
strategy:
matrix:
include:
- arch: arm
arm: 5
- arch: arm
arm: 6
- arch: arm
arm: 7
- arch: arm64
- arch: amd64
- arch: 386
runs-on: ubuntu-latest
steps:
- name: Install Go
uses: actions/setup-go@v2
with:
go-version: 1.17.x
- uses: actions/checkout@v2
- uses: actions/cache@v2
with:
path: ~/go/pkg/mod
key: ${{ runner.os }}-go-${{ hashFiles('**/go.sum') }}
restore-keys: |
${{ runner.os }}-go-
- name: Build
run: go build -v ./...
env:
GOOS: linux
GOARCH: ${{ matrix.arch }}
GOARM: ${{ matrix.arm }}
- uses: actions/upload-artifact@v1
with:
name: avahi2dns-linux-${{ matrix.arch }}${{ matrix.arm }}
path: avahi2dns

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@ -1,2 +1,82 @@
# avahi2dns
# avahi2dns [![Build](https://github.com/LouisBrunner/avahi2dns/actions/workflows/build.yml/badge.svg)](https://github.com/LouisBrunner/avahi2dns/actions/workflows/build.yml)
Small DNS server which interface with avahi (perfect for Alpine Linux and musl)
## Building
Requires go 1.16 or later
```
go build
```
## Usage
```shell
$ ./avahi2dns -h
Usage: avahi2dns [--domains DOMAINS] [--addr ADDR] [--port PORT] [--debug]
Options:
--domains DOMAINS, -d DOMAINS
comma-separated list of domains to resolve
--addr ADDR, -a ADDR address to bind on [default: localhost]
--port PORT, -p PORT port to bind on [default: 53]
--debug, -v also include debug information [default: false]
--help, -h display this help and exit
```
### Examples
By default the server will bind to port 53 on localhost (not accessible outside the computer) and resolve any domain with the following extensions: `home`, `internal`, `intranet`, `lan`, `local`, `private`, `test`
```shell
$ sudo ./avahi2dns
INFO[0000] starting DNS server addr="localhost:53"
...
```
Settings can be changed through command-line arguments or environment variables:
```shell
$ ./avahi2dns -p 5454 -a '0.0.0.0' -d 'local,home'
or
$ BIND='0.0.0.0' PORT=5454 ./avahi2dns -d 'local,home'
```
You can also use the debug flag if you need more information about what the server is doing (probably overkill):
```shell
$ ./avahi2dns -v -p 5454
DEBU[0000]avahi2dns/server.go:14 main.runServer() connection to dbus...
DEBU[0000]avahi2dns/server.go:21 main.runServer() connection to avahi through dbus...
DEBU[0000]avahi2dns/server.go:37 main.runServer() adding dns handler domain=home
...
```
## Using with Alpine and Docker on Linux
Linux DNS-resolution is done by the standard library (through functions like `getaddrinfo` or `gethostbyname`), unfortunately `musl` used by Alpine Linux doesn't support mdns out-of-the-box.
However you can easily add this lookup through `avahi2dns`:
```shell
$ sudo ./avahi2dns &
INFO[0000] starting DNS server addr="localhost:53"
$ docker run --rm --entrypoint ash --net=host alpine -c 'apk add iputils && echo "nameserver 127.0.0.1" >> /etc/resolv.conf && ping your-name-host.local'
fetch https://dl-cdn.alpinelinux.org/alpine/v3.14/main/armv7/APKINDEX.tar.gz
fetch https://dl-cdn.alpinelinux.org/alpine/v3.14/community/armv7/APKINDEX.tar.gz
(1/2) Installing libcap (2.50-r0)
(2/2) Installing iputils (20210202-r0)
Executing busybox-1.33.1-r3.trigger
OK: 4 MiB in 16 packages
INFO[0006] forwarding query to avahi component=main name=your-name-host.local. protocol=0 type=A
INFO[0006] forwarding query to avahi component=main name=your-name-host.local. protocol=1 type=AAAA
PING your-name-host.local (172.16.16.2) 56(84) bytes of data.
64 bytes from 172.16.16.2 (172.16.16.2): icmp_seq=1 ttl=64 time=0.456 ms
64 bytes from 172.16.16.2 (172.16.16.2): icmp_seq=2 ttl=64 time=0.426 ms
64 bytes from 172.16.16.2 (172.16.16.2): icmp_seq=3 ttl=64 time=0.429 ms
64 bytes from 172.16.16.2 (172.16.16.2): icmp_seq=4 ttl=64 time=0.418 ms
```
Note: this requires your Docker container to use `--net=host` instead of the default `--net=bridge`, but that it might be possible without using the latest Docker distributions
Note: `avahi2dns` is run as a background job for the sake of demonstration, you should really run it through `systemd` or similar

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@ -2,7 +2,6 @@ package main
import (
"fmt"
"log"
"github.com/holoplot/go-avahi"
"github.com/miekg/dns"
@ -15,7 +14,7 @@ func createDNSReply(logger *logrus.Entry, aserver *avahi.Server, r *dns.Msg) *dn
switch r.Opcode {
case dns.OpcodeQuery:
for _, q := range m.Question {
for _, q := range r.Question {
switch q.Qtype {
case dns.TypeA:
rr, err := avahiToRecord(logger, aserver, q.Name, avahi.ProtoInet, "A")
@ -55,7 +54,6 @@ func avahiToRecord(logger *logrus.Entry, aserver *avahi.Server, name string, pro
if err != nil {
return nil, fmt.Errorf("avahi resolve failure: %w", err)
}
log.Println("ResolveHostName:", hn)
rr, err := dns.NewRR(fmt.Sprintf("%s %s %s", name, recordType, hn.Address))
if err != nil {
return nil, fmt.Errorf("failured to create record: %w", err)