allow setting forward IP address for blocked domains

dns.go

@@ -13,24 +13,24 @@ import (
 )
 
 type dnsHandler struct {
-	Config     Configuration
-	httpBindIP net.IP
-	logger     *log.Logger
-	Resolver   DNSResolver
-	Blocklist  BlocklistManager
-	Cache      DNSCacher
+	Config         Configuration
+	blockForwardIP net.IP
+	logger         *log.Logger
+	Resolver       DNSResolver
+	Blocklist      BlocklistManager
+	Cache          DNSCacher
 }
 
 //NewDNSHandler creates a new DNS server handler
-func NewDNSHandler(httpBindIP string, cache DNSCacher, blocklist BlocklistManager, r DNSResolver, cfg Configuration) (dns.Handler, error) {
+func NewDNSHandler(blockForwardIP 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,
-		httpBindIP: net.ParseIP(httpBindIP),
-		Resolver:   r,
-		Config:     cfg,
-		Blocklist:  blocklist,
-		Cache:      cache,
+		logger:         l,
+		blockForwardIP: net.ParseIP(blockForwardIP),
+		Resolver:       r,
+		Config:         cfg,
+		Blocklist:      blocklist,
+		Cache:          cache,
 	}, nil
 }
 
@@ -68,7 +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: h.httpBindIP})
+			msg.Answer = append(msg.Answer, &dns.A{Hdr: header, A: h.blockForwardIP})
 		} else if cacheAnswers, ok := h.Cache.Get(domain); ok && len(cacheAnswers) > 0 {
 			msg.Answer = append(msg.Answer, cacheAnswers...)
 		} else {

main.go

@@ -12,9 +12,10 @@ 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 (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)")
+	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 (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)")
+	blockForwardAddr = flag.String("block-forward-ip", "127.0.0.1", "IP address to forward blocked traffic to. Preferably has https running.")
 )
 
 func main() {
@@ -47,7 +48,7 @@ func main() {
 		ips = append(ips, net.ParseIP(strIP))
 	}
 
-	handler, err := NewDNSHandler(*httpAddress, &memoryDNSCacher{TTL: time.Minute}, domainBlacklist, DNSResolver(ips), *cfg)
+	handler, err := NewDNSHandler(*blockForwardAddr, &memoryDNSCacher{TTL: time.Minute}, domainBlacklist, DNSResolver(ips), *cfg)
 	if err != nil {
 		log.Fatal(err)
 	}