From 01e05e8df5f56d605dfd75456a424527e76a2955 Mon Sep 17 00:00:00 2001
From: radhitya <alif@radhitya.org>
Date: Sat, 13 Jun 2026 12:46:38 +0700
Subject: dns codec, udp server (reuseport, 4096 buffers), tcp server, doh
 listener post get without tls, concurrent, ends0, fuzz)

---
 internal/server/server.go | 147 ++++++++++++++++++++++++----------------------
 1 file changed, 78 insertions(+), 69 deletions(-)

(limited to 'internal/server/server.go')

diff --git a/internal/server/server.go b/internal/server/server.go
index 01bda09..f40648e 100644
--- a/internal/server/server.go
+++ b/internal/server/server.go
@@ -3,50 +3,95 @@ package server
 import (
 	"context"
 	"log/slog"
+	"net/http"
 	"time"
 
 	"github.com/miekg/dns"
 )
 
 type Server struct {
-	addr string
 	logger *slog.Logger
-	inner *dns.Server
+	udp    *dns.Server
+	tcp    *dns.Server
+	doh    *http.Server
 }
 
-func New(addr string, logger *slog.Logger) (*Server, error) {
+func New(udpAddr, tcpAddr, dohAddr string, logger *slog.Logger) (*Server, error) {
 	mux := dns.NewServeMux()
 	mux.HandleFunc(".", handleQuery)
 
-	inner := &dns.Server{
-		Addr: addr,
-		Net: "udp",
-		Handler: mux,
-		UDPSize: 4096,
-		ReadTimeout: 5 * time.Second,
-		WriteTimeout: 5 * time.Second,
+	s := &Server{logger: logger}
+
+	if udpAddr != "" {
+		s.udp = &dns.Server{
+			Addr:         udpAddr,
+			Net:          "udp",
+			Handler:      mux,
+			UDPSize:      4096,
+			ReadTimeout:  5 * time.Second,
+			WriteTimeout: 5 * time.Second,
+			ReusePort:    true,
+		}
 	}
-	return &Server{
-		addr: addr,
-		logger: logger,
-		inner: inner,
-	}, nil
-}
 
+	if tcpAddr != "" {
+		s.tcp = &dns.Server{
+			Addr:         tcpAddr,
+			Net:          "tcp",
+			Handler:      mux,
+			ReadTimeout:  5 * time.Second,
+			WriteTimeout: 5 * time.Second,
+		}
+	}
+
+	if dohAddr != "" {
+		dohMux := http.NewServeMux()
+		dohMux.HandleFunc("/dns-query", s.dohHandler)
+		s.doh = &http.Server{
+			Addr:         dohAddr,
+			Handler:      dohMux,
+			ReadTimeout:  5 * time.Second,
+			WriteTimeout: 5 * time.Second,
+		}
+	}
+	return s, nil
+}
 func (s *Server) Run(ctx context.Context) error {
-	errCh := make(chan error, 1)
-	go func() {
-		s.logger.Info("udp listener active", "addr", s.addr)
-		errCh <- s.inner.ListenAndServe()
-	}()
+	errCh := make(chan error, 3)
+	if s.udp != nil {
+		go func() {
+			s.logger.Info("udp listener active", "addr", s.udp.Addr)
+			errCh <- s.udp.ListenAndServe()
+		}()
+	}
+
+	if s.tcp != nil {
+		go func() {
+			s.logger.Info("tcp listener active", "addr", s.tcp.Addr)
+			errCh <- s.tcp.ListenAndServe()
+		}()
+	}
+
+	if s.doh != nil {
+		go func() {
+			s.logger.Info("doh listener active", "addr", s.doh.Addr)
+			errCh <- s.doh.ListenAndServe()
+		}()
+	}
 
 	select {
 	case <-ctx.Done():
-		shutdownCtx, cancel := context.WithTimeout(context.Background(), 5 *time.Second)
+		shutdownCtx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
 		defer cancel()
-		if err := s.inner.ShutdownContext(shutdownCtx); err != nil {
-			s.logger.Error("graceful shutdown failed", "err", err)
-			return err
+
+		if s.udp != nil {
+			s.udp.ShutdownContext(shutdownCtx)
+		}
+		if s.tcp != nil {
+			s.tcp.ShutdownContext(shutdownCtx)
+		}
+		if s.doh != nil {
+			s.doh.Shutdown(shutdownCtx)
 		}
 		return ctx.Err()
 	case err := <-errCh:
@@ -55,50 +100,14 @@ func (s *Server) Run(ctx context.Context) error {
 }
 
 func (s *Server) Close() error {
-	return s.inner.Shutdown()
-}
-
-func handleQuery(w dns.ResponseWriter, req *dns.Msg) {
-	if len(req.Question) == 0 {
-		m := new(dns.Msg)
-		m.SetRcode(req, dns.RcodeFormatError)
-		_ = w.WriteMsg(m)
-		return
+	if s.udp != nil {
+		s.udp.Shutdown()
 	}
-
-	q := req.Question[0]
-	resp := new(dns.Msg)
-	resp.SetReply(req)
-	resp.Authoritative = false
-
-	if q.Name == "example.com." && q.Qtype == dns.TypeA {
-		resp.Answer = []dns.RR{
-			&dns.A{
-				Hdr: dns.RR_Header{
-					Name: q.Name,
-					Rrtype: dns.TypeA,
-					Class: dns.ClassINET,
-					Ttl: 60,
-				},
-				A: []byte{127,0,0,1},
-			},
-		}
-	} else {
-		resp.Rcode = dns.RcodeNameError
+	if s.tcp != nil {
+		s.tcp.Shutdown()
 	}
-
-	if err := w.WriteMsg(resp); err != nil {
-		slog.Error("write response failed",
-		"err", err,
-		"qname", q.Name,
-		"qtype", dns.TypeToString[q.Qtype],
-	)
-	return
-}
-slog.Info("query served",
-"qname", q.Name,
-"qtype", dns.TypeToString[q.Qtype],
-"rcode", dns.RcodeToString[resp.Rcode],
-"client", w.RemoteAddr().String(),
-)
+	if s.doh != nil {
+		s.doh.Close()
+	}
+	return nil
 }
-- 
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