Initial commit, PoC quality

dns.go

@@ -0,0 +1,104 @@
+package main
+
+import (
+	"fmt"
+	"github.com/miekg/dns"
+	"time"
+)
+
+func readQuery(m *dns.Msg) {
+	for _, que := range m.Question {
+		if rr, rc, err := answer(que); err == nil {
+			m.MsgHdr.Rcode = rc
+			for _, r := range rr {
+				m.Answer = append(m.Answer, r)
+			}
+		}
+	}
+}
+
+func answerTXT(q dns.Question) ([]dns.RR, int, error) {
+	var ra []dns.RR
+	var rcode int = dns.RcodeNameError
+	var domain string = q.Name
+
+	atxt, err := DB.GetByDomain(domain)
+	if err != nil {
+		log.Errorf("Error while trying to get record [%v]", err)
+		return ra, dns.RcodeNameError, err
+	}
+	for _, v := range atxt {
+		if len(v.Value) > 0 {
+			r := new(dns.TXT)
+			r.Hdr = dns.RR_Header{Name: domain, Rrtype: dns.TypeTXT, Class: dns.ClassINET, Ttl: 1}
+			r.Txt = append(r.Txt, v.Value)
+			ra = append(ra, r)
+			rcode = dns.RcodeSuccess
+		}
+	}
+	log.Debugf("Answering TXT question for domain [%s]", domain)
+	return ra, rcode, nil
+}
+
+func answer(q dns.Question) ([]dns.RR, int, error) {
+	if q.Qtype == dns.TypeTXT {
+		return answerTXT(q)
+	}
+	var r []dns.RR
+	var rcode int = dns.RcodeSuccess
+	var domain string = q.Name
+	var rtype uint16 = q.Qtype
+	r, ok := RR.Records[rtype][domain]
+	if !ok {
+		rcode = dns.RcodeNameError
+	}
+	log.Debugf("Answering [%s] question for domain [%s] with rcode [%s]", dns.TypeToString[rtype], domain, dns.RcodeToString[rcode])
+	return r, rcode, nil
+}
+
+func handleRequest(w dns.ResponseWriter, r *dns.Msg) {
+	m := new(dns.Msg)
+	m.SetReply(r)
+
+	if r.Opcode == dns.OpcodeQuery {
+		readQuery(m)
+	}
+
+	w.WriteMsg(m)
+}
+
+// Parse config records
+func (r *Records) Parse(recs []string) {
+	rrmap := make(map[uint16]map[string][]dns.RR)
+	for _, v := range recs {
+		rr, err := dns.NewRR(v)
+		if err != nil {
+			log.Errorf("Could not parse RR from config: [%v] for RR: [%s]", err, v)
+			continue
+		}
+		// Add parsed RR to the list
+		rrmap = AppendRR(rrmap, rr)
+	}
+	// Create serial
+	serial := time.Now().Format("2006010215")
+	// Add SOA
+	SOAstring := fmt.Sprintf("%s. SOA %s. %s. %s 28800 7200 604800 86400", DnsConf.General.Domain, DnsConf.General.Nsname, DnsConf.General.Nsadmin, serial)
+	soarr, err := dns.NewRR(SOAstring)
+	if err != nil {
+		log.Errorf("Error [%v] while trying to add SOA record: [%s]", err, SOAstring)
+	} else {
+		rrmap = AppendRR(rrmap, soarr)
+	}
+	r.Records = rrmap
+}
+
+func AppendRR(rrmap map[uint16]map[string][]dns.RR, rr dns.RR) map[uint16]map[string][]dns.RR {
+	_, ok := rrmap[rr.Header().Rrtype]
+	if !ok {
+		newrr := make(map[string][]dns.RR)
+		rrmap[rr.Header().Rrtype] = newrr
+	}
+	rrmap[rr.Header().Rrtype][rr.Header().Name] = append(rrmap[rr.Header().Rrtype][rr.Header().Name], rr)
+	log.Debugf("Adding new record of type [%s] for domain [%s]", dns.TypeToString[rr.Header().Rrtype], rr.Header().Name)
+	return rrmap
+}