Disallow access from IP addresses

main.go

@@ -12,6 +12,7 @@ import (
 	"os"
 	"regexp"
 	"runtime"
+	"strings"
 	"sync/atomic"
 	"syscall"
 	"time"
@@ -251,6 +252,12 @@ func root(w http.ResponseWriter, req *http.Request) {
 // CustomHandler wraps the default promhttp.Handler with custom logic
 func metricsHandler() http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
+		// To prevent accessing from the bare IP address
+		if req.Host == "" || net.ParseIP(strings.Split(req.Host, ":")[0]) != nil {
+			w.WriteHeader(444)
+			return
+		}
+
 		metrics.Uptime.Set(float64(time.Duration(time.Since(programInit).Seconds())))
 		promhttp.Handler().ServeHTTP(w, req)
 	})
@@ -296,10 +303,30 @@ func requestPerMinute() {
 	}
 }
 
-func beforeAll(next http.HandlerFunc) http.HandlerFunc {
+func beforeMisc(next http.HandlerFunc) http.HandlerFunc {
 	return func(w http.ResponseWriter, req *http.Request) {
 		defer panicHandler(w)
 
+		// To prevent accessing from the bare IP address
+		if req.Host == "" || net.ParseIP(strings.Split(req.Host, ":")[0]) != nil {
+			w.WriteHeader(444)
+			return
+		}
+
+		next(w, req)
+	}
+}
+
+func beforeProxy(next http.HandlerFunc) http.HandlerFunc {
+	return func(w http.ResponseWriter, req *http.Request) {
+		defer panicHandler(w)
+
+		// To prevent accessing from the bare IP address
+		if req.Host == "" || net.ParseIP(strings.Split(req.Host, ":")[0]) != nil {
+			w.WriteHeader(444)
+			return
+		}
+
 		if h3s {
 			w.Header().Set("Alt-Svc", "h3=\":8443\"; ma=86400")
 		}
@@ -378,9 +405,10 @@ func main() {
 
 	mux := http.NewServeMux()
 
-	mux.HandleFunc("/", root)
-	mux.HandleFunc("/health", health)
-	mux.HandleFunc("/stats", stats)
+	// MISC ROUTES
+	mux.HandleFunc("/", beforeMisc(root))
+	mux.HandleFunc("/health", beforeMisc(health))
+	mux.HandleFunc("/stats", beforeMisc(stats))
 
 	prometheus.MustRegister(metrics.Uptime)
 	prometheus.MustRegister(metrics.ActiveConnections)
@@ -396,13 +424,14 @@ func main() {
 
 	mux.Handle("/metrics", metricsHandler())
 
-	mux.HandleFunc("/videoplayback", beforeAll(videoplayback))
-	mux.HandleFunc("/vi/", beforeAll(vi))
-	mux.HandleFunc("/vi_webp/", beforeAll(vi))
-	mux.HandleFunc("/sb/", beforeAll(vi))
-	mux.HandleFunc("/ggpht/", beforeAll(ggpht))
-	mux.HandleFunc("/a/", beforeAll(ggpht))
-	mux.HandleFunc("/ytc/", beforeAll(ggpht))
+	// PROXY ROUTES
+	mux.HandleFunc("/videoplayback", beforeProxy(videoplayback))
+	mux.HandleFunc("/vi/", beforeProxy(vi))
+	mux.HandleFunc("/vi_webp/", beforeProxy(vi))
+	mux.HandleFunc("/sb/", beforeProxy(vi))
+	mux.HandleFunc("/ggpht/", beforeProxy(ggpht))
+	mux.HandleFunc("/a/", beforeProxy(ggpht))
+	mux.HandleFunc("/ytc/", beforeProxy(ggpht))
 
 	go requestPerSecond()
 	go requestPerMinute()