From 4c2a201622839930bfb7ad481d38bd9fccf11d10 Mon Sep 17 00:00:00 2001
From: marek <marek.wojt@web.de>
Date: Sun, 17 Oct 2021 17:03:15 +0200
Subject: [PATCH] Verbesserungen DNS-Server

---
 dns/dns.go | 69 ++++++++++++++++++++++++++++++++++++++----------------
 main.go    |  4 +++-
 2 files changed, 52 insertions(+), 21 deletions(-)

diff --git a/dns/dns.go b/dns/dns.go
index be3f57f..edc0d37 100644
--- a/dns/dns.go
+++ b/dns/dns.go
@@ -11,23 +11,23 @@ import (
 )
 
 type domain struct {
-	Root  string
-	Mutv4 sync.RWMutex
-	Mutv6 sync.RWMutex
-	Ipv4  map[string]string
-	Ipv6  map[string]string
+	root  string
+	mutv4 sync.RWMutex
+	mutv6 sync.RWMutex
+	ipv4  map[string]string
+	ipv6  map[string]string
 }
 
-var Domains = []*domain{}
+var domains = []*domain{}
 
 func parseQuery(m *dns.Msg, currentDomain *domain) {
 	for _, q := range m.Question {
 		switch q.Qtype {
 		case dns.TypeA:
 			log.Printf("Query for A record of %s\n", q.Name)
-			currentDomain.Mutv4.RLock()
-			ip := currentDomain.Ipv4[q.Name]
-			currentDomain.Mutv4.RUnlock()
+			currentDomain.mutv4.RLock()
+			ip := currentDomain.ipv4[q.Name]
+			currentDomain.mutv4.RUnlock()
 			if ip != "" {
 				rr, err := dns.NewRR(fmt.Sprintf("%s A %s", q.Name, ip))
 				if err == nil {
@@ -36,9 +36,9 @@ func parseQuery(m *dns.Msg, currentDomain *domain) {
 			}
 		case dns.TypeAAAA:
 			log.Printf("Query for AAAA record of %s\n", q.Name)
-			currentDomain.Mutv6.RLock()
-			ip := currentDomain.Ipv6[q.Name]
-			currentDomain.Mutv6.RUnlock()
+			currentDomain.mutv6.RLock()
+			ip := currentDomain.ipv6[q.Name]
+			currentDomain.mutv6.RUnlock()
 			if ip != "" {
 				rr, err := dns.NewRR(fmt.Sprintf("%s AAAA %s", q.Name, ip))
 				if err == nil {
@@ -64,21 +64,50 @@ func handleDnsRequest(currentDomain *domain) func(w dns.ResponseWriter, r *dns.M
 	}
 }
 
-func Run() error {
+func Load() {
+	for _, currentDomain := range config.Config.Domains {
+		domains = append(domains, &domain{
+			root: currentDomain,
+		})
+	}
+}
+
+func Run() (*dns.Server, error) {
 	// attach request handler func
-	for _, currentDomain := range Domains {
-		dns.HandleFunc(currentDomain.Root, handleDnsRequest(currentDomain))
+	for _, currentDomain := range domains {
+		dns.HandleFunc(currentDomain.root, handleDnsRequest(currentDomain))
 	}
 
 	// start server
-	port := config.Config.Port
-	server := &dns.Server{Addr: ":" + strconv.Itoa(int(port)), Net: "udp"}
-	log.Printf("Starting DNS at %d\n", port)
+	server := &dns.Server{Addr: ":" + strconv.Itoa(int(config.Config.Port)), Net: "udp"}
+	log.Printf("Starting DNS at %d\n", config.Config.Port)
 	err := server.ListenAndServe()
 	if err != nil {
 		server.Shutdown()
-		return err
+		return server, err
 	}
 
-	return nil
+	return server, nil
+}
+
+func UpdateIpv6(domain string, ipv6 string) {
+	for _, currentDomain := range domains {
+		if dns.IsSubDomain(currentDomain.root, domain) {
+			currentDomain.mutv6.Lock()
+			currentDomain.ipv6[domain] = ipv6
+			currentDomain.mutv6.Unlock()
+			break
+		}
+	}
+}
+
+func UpdateIpv4(domain string, ipv4 string) {
+	for _, currentDomain := range domains {
+		if dns.IsSubDomain(currentDomain.root, domain) {
+			currentDomain.mutv4.Lock()
+			currentDomain.ipv4[domain] = ipv4
+			currentDomain.mutv4.Unlock()
+			break
+		}
+	}
 }
diff --git a/main.go b/main.go
index 7070785..a9685dc 100644
--- a/main.go
+++ b/main.go
@@ -20,8 +20,10 @@ func main() {
 		log.Fatalf("Failed to load configuration: %s\n ", err.Error())
 	}
 
-	err = dns.Run()
+	dns.Load()
+	server, err := dns.Run()
 	if err != nil {
 		log.Fatalf("Failed to start DNS server: %s\n ", err.Error())
 	}
+	defer server.Shutdown()
 }