feat: add dedicated WebSocket service for subdomain ping

go.mod

@@ -9,4 +9,7 @@ require (
 	golang.org/x/net v0.33.0
 )
 
-require golang.org/x/sys v0.29.0 // indirect
+require (
+	github.com/gorilla/websocket v1.5.3 // indirect
+	golang.org/x/sys v0.29.0 // indirect
+)

go.sum

@@ -2,6 +2,8 @@ github.com/a-h/templ v0.3.833 h1:L/KOk/0VvVTBegtE0fp2RJQiBm7/52Zxv5fqlEHiQUU=
 github.com/a-h/templ v0.3.833/go.mod h1:cAu4AiZhtJfBjMY0HASlyzvkrtjnHWPeEsyGK2YYmfk=
 github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
 github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
+github.com/gorilla/websocket v1.5.3 h1:saDtZ6Pbx/0u+bgYQ3q96pZgCzfhKXGPqt7kZ72aNNg=
+github.com/gorilla/websocket v1.5.3/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
 github.com/joho/godotenv v1.5.1 h1:7eLL/+HRGLY0ldzfGMeQkb7vMd0as4CfYvUVzLqw0N0=
 github.com/joho/godotenv v1.5.1/go.mod h1:f4LDr5Voq0i2e/R5DDNOoa2zzDfwtkZa6DnEwAbqwq4=
 golang.org/x/crypto v0.32.0 h1:euUpcYgM8WcP71gNpTqQCn6rC2t6ULUPiOzfWaXVVfc=

server/http.go

@@ -7,11 +7,57 @@ import (
 	"fmt"
 	"log"
 	"net"
+	"net/http"
 	"strings"
 	"tunnel_pls/session"
 	"tunnel_pls/utils"
+
+	"github.com/gorilla/websocket"
 )
 
+var upgrader = websocket.Upgrader{
+	ReadBufferSize:  1024,
+	WriteBufferSize: 1024,
+}
+
+type connResponseWriter struct {
+	conn   net.Conn
+	header http.Header
+	wrote  bool
+}
+
+func (w *connResponseWriter) Header() http.Header {
+	if w.header == nil {
+		w.header = make(http.Header)
+	}
+	return w.header
+}
+
+func (w *connResponseWriter) WriteHeader(statusCode int) {
+	if w.wrote {
+		return
+	}
+	w.wrote = true
+	fmt.Fprintf(w.conn, "HTTP/1.1 %d %s\r\n", statusCode, http.StatusText(statusCode))
+	w.header.Write(w.conn)
+	fmt.Fprint(w.conn, "\r\n")
+}
+
+func (w *connResponseWriter) Write(b []byte) (int, error) {
+	if !w.wrote {
+		w.WriteHeader(http.StatusOK)
+	}
+	return w.conn.Write(b)
+}
+
+func (w *connResponseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
+	rw := bufio.NewReadWriter(
+		bufio.NewReader(w.conn),
+		bufio.NewWriter(w.conn),
+	)
+	return w.conn, rw, nil
+}
+
 var redirectTLS = false
 
 func NewHTTPServer() error {
@@ -72,6 +118,40 @@ func Handler(conn net.Conn) {
 		return
 	}
 
+	if slug == "ping" {
+		req, err := http.ReadRequest(reader)
+		if err != nil {
+			log.Println("failed to parse HTTP request:", err)
+			return
+		}
+		rw := &connResponseWriter{conn: conn}
+
+		wsConn, err := upgrader.Upgrade(rw, req, nil)
+		if err != nil {
+			if !strings.Contains(err.Error(), "the client is not using the websocket protocol") {
+				log.Println("Upgrade failed:", err)
+			}
+			err := conn.Close()
+			if err != nil {
+				log.Println("failed to close connection:", err)
+				return
+			}
+			return
+		}
+
+		err = wsConn.WriteMessage(websocket.TextMessage, []byte("pong"))
+		if err != nil {
+			log.Println("failed to write pong:", err)
+			return
+		}
+		err = wsConn.Close()
+		if err != nil {
+			log.Println("websocket close failed :", err)
+			return
+		}
+		return
+	}
+
 	sshSession, ok := session.Clients[slug]
 	if !ok {
 		conn.Write([]byte("HTTP/1.1 400 Bad Request\r\n\r\n"))

server/https.go

@@ -6,9 +6,12 @@ import (
 	"errors"
 	"log"
 	"net"
+	"net/http"
 	"strings"
 	"tunnel_pls/session"
 	"tunnel_pls/utils"
+
+	"github.com/gorilla/websocket"
 )
 
 func NewHTTPSServer() error {
@@ -62,6 +65,40 @@ func HandlerTLS(conn net.Conn) {
 	}
 	slug := host[0]
 
+	if slug == "ping" {
+		req, err := http.ReadRequest(reader)
+		if err != nil {
+			log.Println("failed to parse HTTP request:", err)
+			return
+		}
+		rw := &connResponseWriter{conn: conn}
+
+		wsConn, err := upgrader.Upgrade(rw, req, nil)
+		if err != nil {
+			if !strings.Contains(err.Error(), "the client is not using the websocket protocol") {
+				log.Println("Upgrade failed:", err)
+			}
+			err := conn.Close()
+			if err != nil {
+				log.Println("failed to close connection:", err)
+				return
+			}
+			return
+		}
+
+		err = wsConn.WriteMessage(websocket.TextMessage, []byte("pong"))
+		if err != nil {
+			log.Println("failed to write pong:", err)
+			return
+		}
+		err = wsConn.Close()
+		if err != nil {
+			log.Println("websocket close failed :", err)
+			return
+		}
+		return
+	}
+
 	sshSession, ok := session.Clients[slug]
 	if !ok {
 		conn.Write([]byte("HTTP/1.1 400 Bad Request\r\n\r\n"))

session/handler.go

@@ -16,8 +16,9 @@ import (
 	"time"
 	portUtil "tunnel_pls/internal/port"
 
-	"golang.org/x/crypto/ssh"
 	"tunnel_pls/utils"
+
+	"golang.org/x/crypto/ssh"
 )
 
 type SessionStatus string
@@ -28,6 +29,10 @@ const (
 	SETUP        SessionStatus = "SETUP"
 )
 
+var forbiddenSlug = []string{
+	"ping",
+}
+
 type UserConnection struct {
 	Reader io.Reader
 	Writer net.Conn
@@ -409,12 +414,21 @@ func (s *Session) handleSlugEditMode(connection ssh.Channel, inSlugEditMode *boo
 	}
 }
 
+func isForbiddenSlug(slug string) bool {
+	for _, s := range forbiddenSlug {
+		if slug == s {
+			return true
+		}
+	}
+	return false
+}
+
 func (s *Session) handleSlugSave(connection ssh.Channel, inSlugEditMode *bool, editSlug *string, commandBuffer *bytes.Buffer) {
 	isValid := isValidSlug(*editSlug)
 
 	connection.Write([]byte("\033[H\033[2J"))
 
-	if isValid {
+	if !isValid {
 		oldSlug := s.Slug
 		newSlug := *editSlug
 
@@ -426,6 +440,11 @@ func (s *Session) handleSlugSave(connection ssh.Channel, inSlugEditMode *bool, e
 		connection.Write([]byte("\r\n\r\n✅ SUBDOMAIN UPDATED ✅\r\n\r\n"))
 		connection.Write([]byte("Your new address is: " + newSlug + "." + utils.Getenv("domain") + "\r\n\r\n"))
 		connection.Write([]byte("Press any key to continue...\r\n"))
+	} else if isForbiddenSlug(*editSlug) {
+		connection.Write([]byte("\r\n\r\n❌ FORBIDDEN SUBDOMAIN ❌\r\n\r\n"))
+		connection.Write([]byte("This subdomain is not allowed.\r\n"))
+		connection.Write([]byte("Please try a different subdomain.\r\n\r\n"))
+		connection.Write([]byte("Press any key to continue...\r\n"))
 	} else {
 		connection.Write([]byte("\r\n\r\n❌ INVALID SUBDOMAIN ❌\r\n\r\n"))
 		connection.Write([]byte("Use only lowercase letters, numbers, and hyphens.\r\n"))