DNS, Config, Auth, Web (leer)

dns/dns.go

@@ -0,0 +1,84 @@
+package dns
+
+import (
+	"fmt"
+	"log"
+	"strconv"
+	"sync"
+
+	"github.com/MarekWojt/gertdns/config"
+	"github.com/miekg/dns"
+)
+
+type domain struct {
+	Root  string
+	Mutv4 sync.RWMutex
+	Mutv6 sync.RWMutex
+	Ipv4  map[string]string
+	Ipv6  map[string]string
+}
+
+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()
+			if ip != "" {
+				rr, err := dns.NewRR(fmt.Sprintf("%s A %s", q.Name, ip))
+				if err == nil {
+					m.Answer = append(m.Answer, rr)
+				}
+			}
+		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()
+			if ip != "" {
+				rr, err := dns.NewRR(fmt.Sprintf("%s AAAA %s", q.Name, ip))
+				if err == nil {
+					m.Answer = append(m.Answer, rr)
+				}
+			}
+		}
+	}
+}
+
+func handleDnsRequest(currentDomain *domain) func(w dns.ResponseWriter, r *dns.Msg) {
+	return func(w dns.ResponseWriter, r *dns.Msg) {
+		m := new(dns.Msg)
+		m.SetReply(r)
+		m.Compress = false
+
+		switch r.Opcode {
+		case dns.OpcodeQuery:
+			parseQuery(m, currentDomain)
+		}
+
+		w.WriteMsg(m)
+	}
+}
+
+func Run() error {
+	// attach request handler func
+	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)
+	err := server.ListenAndServe()
+	if err != nil {
+		server.Shutdown()
+		return err
+	}
+
+	return nil
+}