refactor: convert structs to interfaces and rename accessors

- Convert struct types to interfaces - Rename getter and setter methods - Add Close method to server interface - Merge handler functionality into session file - Handle lifecycle.Connection().Wait() - fix panic on nil connection in SSH server
2026-01-16 15:17:33 +07:00
parent dbdf8094fa
commit 19135ceb42
5 changed files with 325 additions and 373 deletions
@@ -1,10 +1,17 @@
 package session

 import (
+	"bytes"
+	"encoding/binary"
+	"errors"
 	"fmt"
+	"io"
 	"log"
+	"net"
 	"time"
 	"tunnel_pls/internal/config"
+	portUtil "tunnel_pls/internal/port"
+	"tunnel_pls/internal/random"
 	"tunnel_pls/session/forwarder"
 	"tunnel_pls/session/interaction"
 	"tunnel_pls/session/lifecycle"
@@ -45,6 +52,8 @@ type session struct {
 	registry    Registry
 }

+var blockedReservedPorts = []uint16{1080, 1433, 1521, 1900, 2049, 3306, 3389, 5432, 5900, 6379, 8080, 8443, 9000, 9200, 27017}
+
 func New(conn *ssh.ServerConn, initialReq <-chan *ssh.Request, sshChan <-chan ssh.NewChannel, sessionRegistry Registry, user string) Session {
 	slugManager := slug.New()
 	forwarderManager := forwarder.New(slugManager)
@@ -151,7 +160,10 @@ func (s *session) Start() error {
 	s.HandleTCPIPForward(tcpipReq)
 	s.interaction.Start()

-	s.lifecycle.Connection().Wait()
+	if err := s.lifecycle.Connection().Wait(); err != nil && !errors.Is(err, io.EOF) && !errors.Is(err, net.ErrClosed) {
+		log.Printf("ssh connection closed with error: %v", err)
+	}
+
 	if err := s.lifecycle.Close(); err != nil {
 		log.Printf("failed to close session: %v", err)
 		return err
@@ -179,3 +191,239 @@ func (s *session) waitForTCPIPForward() *ssh.Request {
 		return nil
 	}
 }
+
+func (s *session) HandleGlobalRequest(GlobalRequest <-chan *ssh.Request) {
+	for req := range GlobalRequest {
+		switch req.Type {
+		case "shell", "pty-req":
+			err := req.Reply(true, nil)
+			if err != nil {
+				log.Println("Failed to reply to request:", err)
+				return
+			}
+		case "window-change":
+			p := req.Payload
+			if len(p) < 16 {
+				log.Println("invalid window-change payload")
+				err := req.Reply(false, nil)
+				if err != nil {
+					log.Println("Failed to reply to request:", err)
+					return
+				}
+				return
+			}
+			cols := binary.BigEndian.Uint32(p[0:4])
+			rows := binary.BigEndian.Uint32(p[4:8])
+
+			s.interaction.SetWH(int(cols), int(rows))
+
+			err := req.Reply(true, nil)
+			if err != nil {
+				log.Println("Failed to reply to request:", err)
+				return
+			}
+		default:
+			log.Println("Unknown request type:", req.Type)
+			err := req.Reply(false, nil)
+			if err != nil {
+				log.Println("Failed to reply to request:", err)
+				return
+			}
+		}
+	}
+}
+
+func (s *session) HandleTCPIPForward(req *ssh.Request) {
+	log.Println("Port forwarding request detected")
+
+	fail := func(msg string) {
+		log.Println(msg)
+		if err := req.Reply(false, nil); err != nil {
+			log.Println("Failed to reply to request:", err)
+			return
+		}
+		if err := s.lifecycle.Close(); err != nil {
+			log.Printf("failed to close session: %v", err)
+		}
+	}
+
+	reader := bytes.NewReader(req.Payload)
+
+	addr, err := readSSHString(reader)
+	if err != nil {
+		fail(fmt.Sprintf("Failed to read address from payload: %v", err))
+		return
+	}
+
+	var rawPortToBind uint32
+	if err = binary.Read(reader, binary.BigEndian, &rawPortToBind); err != nil {
+		fail(fmt.Sprintf("Failed to read port from payload: %v", err))
+		return
+	}
+
+	if rawPortToBind > 65535 {
+		fail(fmt.Sprintf("Port %d is larger than allowed port of 65535", rawPortToBind))
+		return
+	}
+
+	portToBind := uint16(rawPortToBind)
+	if isBlockedPort(portToBind) {
+		fail(fmt.Sprintf("Port %d is blocked or restricted", portToBind))
+		return
+	}
+
+	switch portToBind {
+	case 80, 443:
+		s.HandleHTTPForward(req, portToBind)
+	default:
+		s.HandleTCPForward(req, addr, portToBind)
+	}
+}
+
+func (s *session) HandleHTTPForward(req *ssh.Request, portToBind uint16) {
+	fail := func(msg string, key *types.SessionKey) {
+		log.Println(msg)
+		if key != nil {
+			s.registry.Remove(*key)
+		}
+		if err := req.Reply(false, nil); err != nil {
+			log.Println("Failed to reply to request:", err)
+		}
+	}
+
+	randomString := random.GenerateRandomString(20)
+	key := types.SessionKey{Id: randomString, Type: types.HTTP}
+	if !s.registry.Register(key, s) {
+		fail(fmt.Sprintf("Failed to register client with slug: %s", randomString), nil)
+		return
+	}
+
+	buf := new(bytes.Buffer)
+	err := binary.Write(buf, binary.BigEndian, uint32(portToBind))
+	if err != nil {
+		fail(fmt.Sprintf("Failed to write port to buffer: %v", err), &key)
+		return
+	}
+	log.Printf("HTTP forwarding approved on port: %d", portToBind)
+
+	err = req.Reply(true, buf.Bytes())
+	if err != nil {
+		fail(fmt.Sprintf("Failed to reply to request: %v", err), &key)
+		return
+	}
+
+	s.forwarder.SetType(types.HTTP)
+	s.forwarder.SetForwardedPort(portToBind)
+	s.slug.Set(randomString)
+	s.lifecycle.SetStatus(types.RUNNING)
+}
+
+func (s *session) HandleTCPForward(req *ssh.Request, addr string, portToBind uint16) {
+	fail := func(msg string) {
+		log.Println(msg)
+		if err := req.Reply(false, nil); err != nil {
+			log.Println("Failed to reply to request:", err)
+			return
+		}
+		if err := s.lifecycle.Close(); err != nil {
+			log.Printf("failed to close session: %v", err)
+		}
+	}
+
+	cleanup := func(msg string, port uint16, listener net.Listener, key *types.SessionKey) {
+		log.Println(msg)
+		if key != nil {
+			s.registry.Remove(*key)
+		}
+		if port != 0 {
+			if setErr := portUtil.Default.SetPortStatus(port, false); setErr != nil {
+				log.Printf("Failed to reset port status: %v", setErr)
+			}
+		}
+		if listener != nil {
+			if closeErr := listener.Close(); closeErr != nil {
+				log.Printf("Failed to close listener: %v", closeErr)
+			}
+		}
+		if err := req.Reply(false, nil); err != nil {
+			log.Println("Failed to reply to request:", err)
+		}
+		_ = s.lifecycle.Close()
+	}
+
+	if portToBind == 0 {
+		unassigned, ok := portUtil.Default.GetUnassignedPort()
+		if !ok {
+			fail("No available port")
+			return
+		}
+		portToBind = unassigned
+	}
+
+	if claimed := portUtil.Default.ClaimPort(portToBind); !claimed {
+		fail(fmt.Sprintf("Port %d is already in use or restricted", portToBind))
+		return
+	}
+
+	log.Printf("Requested forwarding on %s:%d", addr, portToBind)
+	listener, err := net.Listen("tcp", fmt.Sprintf("0.0.0.0:%d", portToBind))
+	if err != nil {
+		cleanup(fmt.Sprintf("Port %d is already in use or restricted", portToBind), portToBind, nil, nil)
+		return
+	}
+
+	key := types.SessionKey{Id: fmt.Sprintf("%d", portToBind), Type: types.TCP}
+
+	if !s.registry.Register(key, s) {
+		cleanup(fmt.Sprintf("Failed to register TCP client with id: %s", key.Id), portToBind, listener, nil)
+		return
+	}
+
+	buf := new(bytes.Buffer)
+	err = binary.Write(buf, binary.BigEndian, uint32(portToBind))
+	if err != nil {
+		cleanup(fmt.Sprintf("Failed to write port to buffer: %v", err), portToBind, listener, &key)
+		return
+	}
+
+	log.Printf("TCP forwarding approved on port: %d", portToBind)
+	err = req.Reply(true, buf.Bytes())
+	if err != nil {
+		cleanup(fmt.Sprintf("Failed to reply to request: %v", err), portToBind, listener, &key)
+		return
+	}
+
+	s.forwarder.SetType(types.TCP)
+	s.forwarder.SetListener(listener)
+	s.forwarder.SetForwardedPort(portToBind)
+	s.slug.Set(key.Id)
+	s.lifecycle.SetStatus(types.RUNNING)
+	go s.forwarder.AcceptTCPConnections()
+}
+
+func readSSHString(reader *bytes.Reader) (string, error) {
+	var length uint32
+	if err := binary.Read(reader, binary.BigEndian, &length); err != nil {
+		return "", err
+	}
+	strBytes := make([]byte, length)
+	if _, err := reader.Read(strBytes); err != nil {
+		return "", err
+	}
+	return string(strBytes), nil
+}
+
+func isBlockedPort(port uint16) bool {
+	if port == 80 || port == 443 {
+		return false
+	}
+	if port < 1024 && port != 0 {
+		return true
+	}
+	for _, p := range blockedReservedPorts {
+		if p == port {
+			return true
+		}
+	}
+	return false
+}