juancwu/ccretdns
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allow custom configuration for ports and db path

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This commit is contained in:
jc 2025-12-31 10:48:02 -05:00
commit 191c6dbdb1
5 changed files with 56 additions and 19 deletions
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4
.env.include.example Normal file
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@ -0,0 +1,4 @@
DNS_PORT=53
API_PORT=8888
DB_PATH=./dns_records.db
DEFAULT_TTL=300

1
.gitignore vendored
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@ -1,5 +1,6 @@
.env
.env.*
!.env.include*
*.db

1
go.mod
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@ -3,6 +3,7 @@ module git.juancwu.dev/juancwu/ccretdns
go 1.25.0
require (
github.com/joho/godotenv v1.5.1
github.com/mattn/go-sqlite3 v1.14.32
github.com/miekg/dns v1.1.69
)

2
go.sum
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@ -1,5 +1,7 @@
github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
github.com/joho/godotenv v1.5.1 h1:7eLL/+HRGLY0ldzfGMeQkb7vMd0as4CfYvUVzLqw0N0=
github.com/joho/godotenv v1.5.1/go.mod h1:f4LDr5Voq0i2e/R5DDNOoa2zzDfwtkZa6DnEwAbqwq4=
github.com/mattn/go-sqlite3 v1.14.32 h1:JD12Ag3oLy1zQA+BNn74xRgaBbdhbNIDYvQUEuuErjs=
github.com/mattn/go-sqlite3 v1.14.32/go.mod h1:Uh1q+B4BYcTPb+yiD3kU8Ct7aC0hY9fxUwlHK0RXw+Y=
github.com/miekg/dns v1.1.69 h1:Kb7Y/1Jo+SG+a2GtfoFUfDkG//csdRPwRLkCsxDG9Sc=

65
main.go
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@ -5,21 +5,18 @@ import (
"encoding/json"
"fmt"
"log"
"log/slog"
"net/http"
"os"
"strconv"
"strings"
"time"
"github.com/joho/godotenv"
_ "github.com/mattn/go-sqlite3"
"github.com/miekg/dns"
)
const (
DBPath = "./dns_records.db"
DNSPort = "53"
APIPort = ":8080"
DefaultTTL = 300
)
type RecordRequest struct {
Domain string `json:"domain"`
IP string `json:"ip"`
@ -30,8 +27,9 @@ type UpstreamRequest struct {
Address string `json:"address"`
}
func initDB() *sql.DB {
db, err := sql.Open("sqlite3", DBPath)
func initDB(dbPath string) *sql.DB {
db, err := sql.Open("sqlite3", dbPath)
if err != nil {
log.Fatal(err)
}
@ -62,6 +60,7 @@ func initDB() *sql.DB {
type DNSResolver struct {
db *sql.DB
defaultTTL int
}
func (resolver *DNSResolver) handleDNSRequest(w dns.ResponseWriter, r *dns.Msg) {
@ -75,7 +74,7 @@ func (resolver *DNSResolver) handleDNSRequest(w dns.ResponseWriter, r *dns.Msg)
ip, err := resolver.getRecordFromDB(q.Name)
if err == nil && ip != "" {
log.Printf("[LOCAL] Resolved %s -> %s", q.Name, ip)
rr, err := dns.NewRR(fmt.Sprintf("%s %d A %s", q.Name, DefaultTTL, ip))
rr, err := dns.NewRR(fmt.Sprintf("%s %d A %s", q.Name, resolver.defaultTTL, ip))
if err == nil {
m.Answer = append(m.Answer, rr)
}
@ -136,7 +135,7 @@ func (resolver *DNSResolver) resolveUpstream(r *dns.Msg) (*dns.Msg, error) {
return nil, fmt.Errorf("all upstreams failed")
}
func startAPIServer(db *sql.DB) {
func startAPIServer(db *sql.DB, apiPort string) {
http.HandleFunc("/records", func(w http.ResponseWriter, r *http.Request) {
if r.Method == http.MethodPost {
var req RecordRequest
@ -206,22 +205,52 @@ func startAPIServer(db *sql.DB) {
}
})
log.Printf("API Listening on %s...", APIPort)
log.Fatal(http.ListenAndServe(APIPort, nil))
log.Printf("API Listening on %s...", apiPort)
log.Fatal(http.ListenAndServe(":"+apiPort, nil))
}
func envString(key, def string) string {
value := os.Getenv(key)
if value == "" {
value = def
}
return value
}
func envInt(key string, def int) int {
value, ok := os.LookupEnv(key)
if !ok || value == "" {
return def
}
val, err := strconv.ParseInt(value, 10, 32)
if err != nil {
slog.Warn("config invalid integer, using default", "key", key, "value", value, "default", def)
return def
}
return int(val)
}
func main() {
db := initDB()
godotenv.Load()
var (
dbPath = envString("DB_PATH", "./dns_records.db")
dnsPort = envString("DNS_PORT", "53")
apiPort = envString("API_PORT", "8888")
defaultTTL = envInt("DEFAULT_TTL", 300)
)
db := initDB(dbPath)
defer db.Close()
go startAPIServer(db)
go startAPIServer(db, apiPort)
resolver := &DNSResolver{db: db}
resolver := &DNSResolver{db: db, defaultTTL: defaultTTL}
dns.HandleFunc(".", resolver.handleDNSRequest)
server := &dns.Server{Addr: ":" + DNSPort, Net: "udp"}
log.Printf("DNS Server listening on port %s...", DNSPort)
server := &dns.Server{Addr: ":" + dnsPort, Net: "udp"}
log.Printf("DNS Server listening on port %s...", dnsPort)
if err := server.ListenAndServe(); err != nil {
log.Fatalf("Failed to set up DNS server: %v", err)