use correct name in dns header, fixes blacklisting

pass http bind address to handler so we can forward blocked domains to our http
server. Should change this to use a custom CLI flag so users can have more control
over this.

blocklists_test.go

@@ -86,7 +86,7 @@ func TestFetchBlockList(t *testing.T) {
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			got, err := FetchBlockList(tt.source)
+			got, err := CreateBlockList(tt.source)
 			if (err != nil) != tt.wantErr {
 				t.Errorf("FetchBlockList() error = %v, wantErr %v", err, tt.wantErr)
 				return

dns.go

@@ -13,22 +13,24 @@ import (
 )
 
 type dnsHandler struct {
-	Config    Configuration
-	logger    *log.Logger
-	Resolver  DNSResolver
-	Blocklist BlocklistManager
-	Cache     DNSCacher
+	Config     Configuration
+	httpBindIP net.IP
+	logger     *log.Logger
+	Resolver   DNSResolver
+	Blocklist  BlocklistManager
+	Cache      DNSCacher
 }
 
 //NewDNSHandler creates a new DNS server handler
-func NewDNSHandler(cache DNSCacher, blocklist BlocklistManager, r DNSResolver, cfg Configuration) (dns.Handler, error) {
+func NewDNSHandler(httpBindIP string, cache DNSCacher, blocklist BlocklistManager, r DNSResolver, cfg Configuration) (dns.Handler, error) {
 	l := log.New(os.Stdout, "[DNS Server] ", log.LUTC|log.Lmicroseconds|log.Lshortfile)
 	return &dnsHandler{
-		logger:    l,
-		Resolver:  r,
-		Config:    cfg,
-		Blocklist: blocklist,
-		Cache:     cache,
+		logger:     l,
+		httpBindIP: net.ParseIP(httpBindIP),
+		Resolver:   r,
+		Config:     cfg,
+		Blocklist:  blocklist,
+		Cache:      cache,
 	}, nil
 }
 
@@ -36,13 +38,14 @@ func (h *dnsHandler) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
 	var msg dns.Msg
 	msg.Authoritative = true
 	msg.RecursionAvailable = true
+	msg.Answer = []dns.RR{}
 	msg.SetReply(r)
 
 	for _, question := range r.Question {
 		rawDomain := question.Name
 		domain := rawDomain[:len(rawDomain)-1]
 		header := dns.RR_Header{
-			Name:   domain,
+			Name:   rawDomain,
 			Rrtype: question.Qtype,
 			Class:  dns.ClassINET,
 			Ttl:    60,
@@ -65,7 +68,7 @@ func (h *dnsHandler) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
 			}
 		} else if list, block := h.Blocklist.IsBlacklisted(domain); block {
 			h.logger.Printf("blocked dns query for '%s' from list '%s'", domain, list)
-			msg.Answer = append(msg.Answer, &dns.A{Hdr: header, A: net.ParseIP("127.0.0.1")})
+			msg.Answer = append(msg.Answer, &dns.A{Hdr: header, A: h.httpBindIP})
 		} else if cacheAnswers, ok := h.Cache.Get(domain); ok && len(cacheAnswers) > 0 {
 			msg.Answer = append(msg.Answer, cacheAnswers...)
 		} else {
@@ -81,7 +84,9 @@ func (h *dnsHandler) ServeDNS(w dns.ResponseWriter, r *dns.Msg) {
 		}
 	}
 
-	w.WriteMsg(&msg)
+	if err := w.WriteMsg(&msg); err != nil {
+		h.logger.Printf("could not write msg: %v", err)
+	}
 }
 
 func shouldBlock(bls []Blocklist, domain string) (string, bool) {

main.go

@@ -13,8 +13,8 @@ import (
 
 var (
 	configFilePath = flag.String("config", "./config.json", "config file path")
-	httpAddress    = flag.String("bind-http", "127.0.0.1", "interface to bind the HTTP server to")
-	dnsAddress     = flag.String("bind-dns", "127.0.0.1", "interface to bind the DNS server to")
+	httpAddress    = flag.String("bind-http", "127.0.0.1", "interface to bind the HTTP server to (0.0.0.0 for all)")
+	dnsAddress     = flag.String("bind-dns", "127.0.0.1", "interface to bind the DNS server to (0.0.0.0 for all)")
 )
 
 func main() {
@@ -47,7 +47,7 @@ func main() {
 		ips = append(ips, net.ParseIP(strIP))
 	}
 
-	handler, err := NewDNSHandler(&memoryDNSCacher{TTL: time.Minute}, domainBlacklist, DNSResolver(ips), *cfg)
+	handler, err := NewDNSHandler(*httpAddress, &memoryDNSCacher{TTL: time.Minute}, domainBlacklist, DNSResolver(ips), *cfg)
 	if err != nil {
 		log.Fatal(err)
 	}