refactor: restructure project architecture

internal/config/config.go

@@ -0,0 +1,35 @@
+package config
+
+import (
+	"log"
+	"os"
+	"strconv"
+
+	"github.com/joho/godotenv"
+)
+
+func init() {
+	if _, err := os.Stat(".env"); err == nil {
+		if err := godotenv.Load(".env"); err != nil {
+			log.Printf("Warning: Failed to load .env file: %s", err)
+		}
+	}
+}
+
+func Getenv(key, defaultValue string) string {
+	val := os.Getenv(key)
+	if val == "" {
+		val = defaultValue
+	}
+
+	return val
+}
+
+func GetBufferSize() int {
+	sizeStr := Getenv("BUFFER_SIZE", "32768")
+	size, err := strconv.Atoi(sizeStr)
+	if err != nil || size < 4096 || size > 1048576 {
+		return 32768
+	}
+	return size
+}

internal/key/key.go

@@ -0,0 +1,67 @@
+package key
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/x509"
+	"encoding/pem"
+	"log"
+	"os"
+	"path/filepath"
+
+	"golang.org/x/crypto/ssh"
+)
+
+func GenerateSSHKeyIfNotExist(keyPath string) error {
+	if _, err := os.Stat(keyPath); err == nil {
+		log.Printf("SSH key already exists at %s", keyPath)
+		return nil
+	}
+
+	log.Printf("SSH key not found at %s, generating new key pair...", keyPath)
+
+	privateKey, err := rsa.GenerateKey(rand.Reader, 4096)
+	if err != nil {
+		return err
+	}
+
+	privateKeyPEM := &pem.Block{
+		Type:  "RSA PRIVATE KEY",
+		Bytes: x509.MarshalPKCS1PrivateKey(privateKey),
+	}
+
+	dir := filepath.Dir(keyPath)
+	if err := os.MkdirAll(dir, 0700); err != nil {
+		return err
+	}
+
+	privateKeyFile, err := os.OpenFile(keyPath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
+	if err != nil {
+		return err
+	}
+	defer privateKeyFile.Close()
+
+	if err := pem.Encode(privateKeyFile, privateKeyPEM); err != nil {
+		return err
+	}
+
+	publicKey, err := ssh.NewPublicKey(&privateKey.PublicKey)
+	if err != nil {
+		return err
+	}
+
+	pubKeyPath := keyPath + ".pub"
+	pubKeyFile, err := os.OpenFile(pubKeyPath, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
+	if err != nil {
+		return err
+	}
+	defer pubKeyFile.Close()
+
+	_, err = pubKeyFile.Write(ssh.MarshalAuthorizedKey(publicKey))
+	if err != nil {
+		return err
+	}
+
+	log.Printf("SSH key pair generated successfully at %s and %s", keyPath, pubKeyPath)
+	return nil
+}

internal/port/port.go

@@ -6,7 +6,7 @@ import (
 	"strconv"
 	"strings"
 	"sync"
-	"tunnel_pls/utils"
+	"tunnel_pls/internal/config"
 )
 
 type Manager interface {
@@ -28,7 +28,7 @@ var Default Manager = &manager{
 }
 
 func init() {
-	rawRange := utils.Getenv("ALLOWED_PORTS", "")
+	rawRange := config.Getenv("ALLOWED_PORTS", "")
 	if rawRange == "" {
 		return
 	}

internal/random/random.go

@@ -0,0 +1,18 @@
+package random
+
+import (
+	mathrand "math/rand"
+	"strings"
+	"time"
+)
+
+func GenerateRandomString(length int) string {
+	const charset = "abcdefghijklmnopqrstuvwxyz"
+	seededRand := mathrand.New(mathrand.NewSource(time.Now().UnixNano() + int64(mathrand.Intn(9999))))
+	var result strings.Builder
+	for i := 0; i < length; i++ {
+		randomIndex := seededRand.Intn(len(charset))
+		result.WriteString(string(charset[randomIndex]))
+	}
+	return result.String()
+}