Merge pull request #1 from vinted/feature/initial_release

dns-parking: inital release

README.md

@@ -1,2 +1,5 @@
 # dns-parking
 Service for parking DNS records
+
+Service sends predefined SOA or NS replies to any domain request.
+See config.json file for configuration options.

cmd/dns-parking/main.go

@@ -0,0 +1,23 @@
+package main
+
+import (
+	"flag"
+	"github.com/vinted/dns-parking/pkg/config"
+	"github.com/vinted/dns-parking/pkg/dns"
+	"log"
+)
+
+func main() {
+	var (
+		configFile    string
+		listenAddress string
+	)
+	flag.StringVar(&configFile, "configFile", "/etc/dns-parking/config.json", "Path to config file.")
+	flag.StringVar(&listenAddress, "listenAddress", "0.0.0.0:53", "Address to bind to.")
+	flag.Parse()
+	err := config.Init(configFile)
+	if err != nil {
+		log.Fatalf("Failed to read configuration. %v", err)
+	}
+	dns.Start(listenAddress)
+}

config.json

@@ -0,0 +1,12 @@
+{
+  "SOARname": "domains.parking.com",
+  "SOASerial": "2023121801",
+  "SOARefresh": "86400",
+  "SOARetry": "7200",
+  "SOAExpire": "3600000",
+  "SOATTL": "3600",
+  "NS": [
+    "ns1.parking.com",
+    "ns2.parking.com"
+  ]
+}

go.mod

@@ -0,0 +1,18 @@
+module github.com/vinted/dns-parking
+
+go 1.21.0
+
+require github.com/miekg/dns v1.1.57
+
+require (
+	github.com/yuin/goldmark v1.4.13 // indirect
+	golang.org/x/crypto v0.14.0 // indirect
+	golang.org/x/mod v0.12.0 // indirect
+	golang.org/x/net v0.17.0 // indirect
+	golang.org/x/sync v0.4.0 // indirect
+	golang.org/x/sys v0.13.0 // indirect
+	golang.org/x/term v0.13.0 // indirect
+	golang.org/x/text v0.13.0 // indirect
+	golang.org/x/tools v0.13.0 // indirect
+	golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7 // indirect
+)

go.sum

@@ -0,0 +1,16 @@
+github.com/miekg/dns v1.1.57 h1:Jzi7ApEIzwEPLHWRcafCN9LZSBbqQpxjt/wpgvg7wcM=
+github.com/miekg/dns v1.1.57/go.mod h1:uqRjCRUuEAA6qsOiJvDd+CFo/vW+y5WR6SNmHE55hZk=
+github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
+golang.org/x/crypto v0.14.0/go.mod h1:MVFd36DqK4CsrnJYDkBA3VC4m2GkXAM0PvzMCn4JQf4=
+golang.org/x/mod v0.12.0 h1:rmsUpXtvNzj340zd98LZ4KntptpfRHwpFOHG188oHXc=
+golang.org/x/mod v0.12.0/go.mod h1:iBbtSCu2XBx23ZKBPSOrRkjjQPZFPuis4dIYUhu/chs=
+golang.org/x/net v0.17.0 h1:pVaXccu2ozPjCXewfr1S7xza/zcXTity9cCdXQYSjIM=
+golang.org/x/net v0.17.0/go.mod h1:NxSsAGuq816PNPmqtQdLE42eU2Fs7NoRIZrHJAlaCOE=
+golang.org/x/sync v0.4.0/go.mod h1:FU7BRWz2tNW+3quACPkgCx/L+uEAv1htQ0V83Z9Rj+Y=
+golang.org/x/sys v0.13.0 h1:Af8nKPmuFypiUBjVoU9V20FiaFXOcuZI21p0ycVYYGE=
+golang.org/x/sys v0.13.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/term v0.13.0/go.mod h1:LTmsnFJwVN6bCy1rVCoS+qHT1HhALEFxKncY3WNNh4U=
+golang.org/x/text v0.13.0/go.mod h1:TvPlkZtksWOMsz7fbANvkp4WM8x/WCo/om8BMLbz+aE=
+golang.org/x/tools v0.13.0 h1:Iey4qkscZuv0VvIt8E0neZjtPVQFSc870HQ448QgEmQ=
+golang.org/x/tools v0.13.0/go.mod h1:HvlwmtVNQAhOuCjW7xxvovg8wbNq7LwfXh/k7wXUl58=
+golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=

pkg/config/config.go

@@ -0,0 +1,44 @@
+package config
+
+import (
+	"encoding/json"
+	"log"
+	"os"
+)
+
+type Cfg struct {
+	SOARname   string
+	SOASerial  string
+	SOARefresh string
+	SOARetry   string
+	SOAExpire  string
+	SOATTL     string
+	NS         []string
+}
+
+var (
+	Config     *Cfg
+	ConfigFile string
+)
+
+func Init(configFile string) error {
+	ConfigFile = configFile
+	content := []byte(`{}`)
+	_, err := os.Stat(ConfigFile)
+	if !os.IsNotExist(err) {
+		content, err = os.ReadFile(ConfigFile)
+		if err != nil {
+			return err
+		}
+	}
+	if len(content) == 0 {
+		content = []byte(`{}`)
+	}
+	err = json.Unmarshal(content, &Config)
+	if err != nil {
+		return err
+	}
+
+	log.Printf("Finished reading config.")
+	return nil
+}

pkg/dns/dns.go

@@ -0,0 +1,57 @@
+package dns
+
+import (
+	"fmt"
+	"github.com/miekg/dns"
+	"github.com/vinted/dns-parking/pkg/config"
+	"log"
+)
+
+func parseQuery(m *dns.Msg) {
+	cfg := *config.Config
+	for _, q := range m.Question {
+		switch q.Qtype {
+		case dns.TypeSOA:
+			log.Printf("SOA for %s\n", q.Name)
+			rr, err := dns.NewRR(fmt.Sprintf("%s %s IN SOA %s. %s. %s %s %s %s %s", q.Name, cfg.SOARefresh, cfg.NS[0], cfg.SOARname, cfg.SOASerial, cfg.SOARefresh, cfg.SOARetry, cfg.SOAExpire, cfg.SOATTL))
+			if err == nil {
+				m.Answer = append(m.Answer, rr)
+			} else {
+				log.Printf("Error sending SOA record: %s\n", err)
+			}
+		case dns.TypeNS:
+			log.Printf("NS for %s\n", q.Name)
+			for _, ns := range config.Config.NS {
+				rr, err := dns.NewRR(fmt.Sprintf("%s %s IN NS %s.", q.Name, config.Config.SOATTL, ns))
+				if err == nil {
+					m.Answer = append(m.Answer, rr)
+				} else {
+					log.Printf("Error sending NS record: %s\n", err)
+				}
+			}
+		}
+	}
+}
+
+func handleDnsRequest(w dns.ResponseWriter, r *dns.Msg) {
+	m := new(dns.Msg)
+	m.SetReply(r)
+	m.Compress = false
+
+	switch r.Opcode {
+	case dns.OpcodeQuery:
+		parseQuery(m)
+	}
+	w.WriteMsg(m)
+}
+
+func Start(listenAddress string) {
+	dns.HandleFunc(".", handleDnsRequest)
+	server := &dns.Server{Addr: listenAddress, Net: "udp"}
+	log.Printf("Server started at %s\n", listenAddress)
+	err := server.ListenAndServe()
+	defer server.Shutdown()
+	if err != nil {
+		log.Fatalf("Failed to start server: %s\n ", err.Error())
+	}
+}