Added support for AAAA records to DNS cache for IPv6 addressing.

sgfw/dns.go

@@ -5,6 +5,7 @@ import (
 	"strings"
 	"sync"
 	"time"
+	"encoding/binary"
 
 //	"github.com/subgraph/go-nfnetlink"
 	"github.com/google/gopacket/layers"
@@ -64,7 +65,7 @@ func (dc *dnsCache) processDNS(pkt *nfqueue.NFQPacket) {
 		return
 	}
 	q := dns.question[0]
-	if q.Qtype == dnsTypeA {
+	if q.Qtype == dnsTypeA || q.Qtype == dnsTypeAAAA {
 		srcip, _ := getPacketIPAddrs(pkt)
 		pinfo := getEmptyPInfo()
 		if !isNSTrusted(srcip) {
@@ -76,7 +77,7 @@ func (dc *dnsCache) processDNS(pkt *nfqueue.NFQPacket) {
 			}
 		}
 //log.Notice("XXX: PROCESS LOOKUP -> ", pinfo)
-		dc.processRecordA(q.Name, dns.answer, pinfo.Pid)
+		dc.processRecordAddress(q.Name, dns.answer, pinfo.Pid)
 		return
 	}
 	log.Infof("Unhandled DNS message: %v", dns)
@@ -106,13 +107,29 @@ func procDeathCallback(pid int, param interface{}) {
 	}
 }
 
-func (dc *dnsCache) processRecordA(name string, answers []dnsRR, pid int) {
+func (dc *dnsCache) processRecordAddress(name string, answers []dnsRR, pid int) {
 	dc.lock.Lock()
 	defer dc.lock.Unlock()
 	for _, rr := range answers {
+		var aBytes []byte = nil
 		switch rec := rr.(type) {
 		case *dnsRR_A:
-			ip := net.IPv4(byte(rec.A>>24), byte(rec.A>>16), byte(rec.A>>8), byte(rec.A)).String()
+			var ipA [4]byte
+			aBytes = ipA[:]
+			binary.BigEndian.PutUint32(aBytes, rec.A)
+		case *dnsRR_AAAA:
+			aBytes = rec.AAAA[:]
+		case *dnsRR_CNAME:
+			// Not that exotic; just ignore it
+		default:
+			log.Warningf("Unexpected RR type in answer section of A response: %v", rec)
+		}
+
+		if aBytes == nil {
+			continue
+		}
+
+		ip := net.IP(aBytes).String()
 		if strings.HasSuffix(name, ".") {
 			name = name[:len(name)-1]
 		}
@@ -145,13 +162,6 @@ func (dc *dnsCache) processRecordA(name string, answers []dnsRR, pid int) {
 		if !FirewallConfig.LogRedact {
 			log.Infof("Adding %s: %s", name, ip)
 		}
-		case *dnsRR_AAAA:
-			log.Warning("AAAA record read from DNS; not supported.")
-		case *dnsRR_CNAME:
-			// Not that exotic; just ignore it
-		default:
-			log.Warningf("Unexpected RR type in answer section of A response: %v", rec)
-		}
 	}
 }