This commit is contained in:
Evan Reichard 2025-09-19 16:35:38 -04:00
parent 84ea3802b8
commit 0223d35b34
4 changed files with 413 additions and 270 deletions

6
.golangci.toml Normal file
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@ -0,0 +1,6 @@
#:schema https://golangci-lint.run/jsonschema/golangci.jsonschema.json
version = "2"
[[linters.exclusions.rules]]
linters = [ "errcheck" ]
source = "^\\s*defer\\s+"

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@ -1,44 +1,34 @@
package cmd
import (
"bytes"
"fmt"
"io"
"log"
"net/http"
"net"
"sync"
"github.com/gorilla/websocket"
"github.com/spf13/cobra"
)
type TunnelRequest struct {
ID string `json:"id"`
Method string `json:"method"`
URL string `json:"url"`
Headers map[string]string `json:"headers"`
Body []byte `json:"body"`
}
type TunnelResponse struct {
ID string `json:"id"`
StatusCode int `json:"status_code"`
Headers map[string]string `json:"headers"`
Body []byte `json:"body"`
type TunnelMessage struct {
Type string `json:"type"`
StreamID string `json:"stream_id"`
Data []byte `json:"data,omitempty"`
}
var serverAddr string
var linkCmd = &cobra.Command{
Use: "link <vhost_location> <local_port>",
Use: "link <vhost_location> <host:port>",
Short: "Create a tunnel link",
Args: cobra.ExactArgs(2),
Run: func(cmd *cobra.Command, args []string) {
vhostLoc := args[0]
localPort := args[1]
hostPort := args[1]
fmt.Printf("Creating tunnel: %s -> localhost:%s\n", vhostLoc, localPort)
fmt.Printf("Creating TCP tunnel: %s -> %s\n", vhostLoc, hostPort)
if err := startTunnel(vhostLoc, localPort); err != nil {
if err := startTCPTunnel(vhostLoc, hostPort); err != nil {
log.Fatal("Failed to start tunnel:", err)
}
},
@ -48,8 +38,7 @@ func init() {
linkCmd.Flags().StringVarP(&serverAddr, "server", "s", "localhost:8080", "Conduit server address")
}
func startTunnel(vhost, localPort string) error {
// Connect to WebSocket
func startTCPTunnel(vhost, hostPort string) error {
wsURL := fmt.Sprintf("ws://%s/_conduit/tunnel?vhost=%s", serverAddr, vhost)
conn, _, err := websocket.DefaultDialer.Dial(wsURL, nil)
if err != nil {
@ -57,80 +46,86 @@ func startTunnel(vhost, localPort string) error {
}
defer conn.Close()
fmt.Printf("Tunnel active! %s.example.com -> localhost:%s\n", vhost, localPort)
fmt.Printf("TCP Tunnel active! %s.example.com -> %s\n", vhost, hostPort)
// Handle incoming requests
// Track active connections
connections := make(map[string]net.Conn)
var connMutex sync.RWMutex
// Handle messages from server
for {
var req TunnelRequest
if err := conn.ReadJSON(&req); err != nil {
log.Printf("Error reading request: %v", err)
var msg TunnelMessage
err := conn.ReadJSON(&msg)
if err != nil {
log.Printf("Error reading from tunnel: %v", err)
break
}
go handleTunnelRequest(conn, &req, localPort)
switch msg.Type {
case "data":
connMutex.RLock()
localConn, exists := connections[msg.StreamID]
connMutex.RUnlock()
if !exists {
// New connection
localConn, err = net.Dial("tcp", hostPort)
if err != nil {
log.Printf("Failed to connect to %s: %v", hostPort, err)
continue
}
connMutex.Lock()
connections[msg.StreamID] = localConn
connMutex.Unlock()
// Start reading from local connection
go func(streamID string, lConn net.Conn) {
defer func() {
connMutex.Lock()
delete(connections, streamID)
connMutex.Unlock()
lConn.Close()
}()
buffer := make([]byte, 4096)
for {
n, err := lConn.Read(buffer)
if err != nil {
break
}
response := TunnelMessage{
Type: "data",
StreamID: streamID,
Data: buffer[:n],
}
if err := conn.WriteJSON(response); err != nil {
break
}
}
}(msg.StreamID, localConn)
}
// Write data to local connection
if _, err := localConn.Write(msg.Data); err != nil {
log.Printf("Error writing to local connection: %v", err)
localConn.Close()
connMutex.Lock()
delete(connections, msg.StreamID)
connMutex.Unlock()
}
case "close":
connMutex.Lock()
if localConn, exists := connections[msg.StreamID]; exists {
localConn.Close()
delete(connections, msg.StreamID)
}
connMutex.Unlock()
}
}
return nil
}
func handleTunnelRequest(conn *websocket.Conn, req *TunnelRequest, localPort string) {
// Make request to local service
localURL := fmt.Sprintf("http://localhost:%s%s", localPort, req.URL)
httpReq, err := http.NewRequest(req.Method, localURL, bytes.NewReader(req.Body))
if err != nil {
sendErrorResponse(conn, req.ID, 500, "Failed to create request")
return
}
// Set headers
for k, v := range req.Headers {
httpReq.Header.Set(k, v)
}
// Make the request
client := &http.Client{}
resp, err := client.Do(httpReq)
if err != nil {
sendErrorResponse(conn, req.ID, 502, "Failed to reach local service")
return
}
defer resp.Body.Close()
// Read response body
body, err := io.ReadAll(resp.Body)
if err != nil {
sendErrorResponse(conn, req.ID, 500, "Failed to read response")
return
}
// Convert response headers
headers := make(map[string]string)
for k, v := range resp.Header {
if len(v) > 0 {
headers[k] = v[0]
}
}
// Send response back
tunnelResp := &TunnelResponse{
ID: req.ID,
StatusCode: resp.StatusCode,
Headers: headers,
Body: body,
}
if err := conn.WriteJSON(tunnelResp); err != nil {
log.Printf("Error sending response: %v", err)
}
}
func sendErrorResponse(conn *websocket.Conn, reqID string, statusCode int, message string) {
resp := &TunnelResponse{
ID: reqID,
StatusCode: statusCode,
Headers: map[string]string{"Content-Type": "text/plain"},
Body: []byte(message),
}
conn.WriteJSON(resp)
}

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@ -1,9 +1,11 @@
package server
import (
"bufio"
"bytes"
"fmt"
"io"
"log"
"net"
"net/http"
"strings"
"sync"
@ -13,25 +15,15 @@ import (
)
type TunnelConnection struct {
conn *websocket.Conn
*websocket.Conn
vhost string
responses map[string]chan *TunnelResponse
mu sync.RWMutex
streams map[string]chan []byte // StreamID -> data channel
}
type TunnelRequest struct {
ID string `json:"id"`
Method string `json:"method"`
URL string `json:"url"`
Headers map[string]string `json:"headers"`
Body []byte `json:"body"`
}
type TunnelResponse struct {
ID string `json:"id"`
StatusCode int `json:"status_code"`
Headers map[string]string `json:"headers"`
Body []byte `json:"body"`
type TunnelMessage struct {
Type string `json:"type"`
StreamID string `json:"stream_id"`
Data []byte `json:"data,omitempty"`
}
type Server struct {
@ -52,175 +44,24 @@ func NewServer() *Server {
}
func (s *Server) Start(addr string) error {
http.HandleFunc("/", s.handleRequest)
http.HandleFunc("/_conduit/tunnel", s.handleTunnel)
http.HandleFunc("/_conduit/status", s.handleStatus)
// Raw TCP listener instead of http.ListenAndServe
listener, err := net.Listen("tcp", addr)
if err != nil {
return err
}
defer listener.Close()
log.Printf("Conduit server listening on %s", addr)
return http.ListenAndServe(addr, nil)
}
func (s *Server) handleRequest(w http.ResponseWriter, r *http.Request) {
host := r.Host
subdomain := s.extractSubdomain(host)
if subdomain == "" {
http.Error(w, "Invalid host", http.StatusBadRequest)
return
}
s.mu.RLock()
tunnel, exists := s.tunnels[subdomain]
s.mu.RUnlock()
if !exists {
http.Error(w, "Tunnel not found", http.StatusNotFound)
return
}
// Create unique request ID
reqID := fmt.Sprintf("%d", time.Now().UnixNano())
// Read request body
body, err := io.ReadAll(r.Body)
if err != nil {
http.Error(w, "Failed to read request body", http.StatusBadRequest)
return
}
defer r.Body.Close()
// Convert headers
headers := make(map[string]string)
for k, v := range r.Header {
if len(v) > 0 {
headers[k] = v[0]
}
}
// Create response channel for this request
respChan := make(chan *TunnelResponse, 1)
tunnel.mu.Lock()
tunnel.responses[reqID] = respChan
tunnel.mu.Unlock()
// Clean up response channel when done
defer func() {
tunnel.mu.Lock()
delete(tunnel.responses, reqID)
tunnel.mu.Unlock()
}()
tunnelReq := &TunnelRequest{
ID: reqID,
Method: r.Method,
URL: r.URL.String(),
Headers: headers,
Body: body,
}
// Send request to tunnel
if err := tunnel.conn.WriteJSON(tunnelReq); err != nil {
log.Printf("Error sending request to tunnel: %v", err)
http.Error(w, "Tunnel communication error", http.StatusServiceUnavailable)
return
}
// Wait for response
select {
case resp := <-respChan:
// Write response headers
for k, v := range resp.Headers {
w.Header().Set(k, v)
}
w.WriteHeader(resp.StatusCode)
w.Write(resp.Body)
case <-time.After(30 * time.Second):
http.Error(w, "Tunnel timeout", http.StatusGatewayTimeout)
}
}
func (s *Server) handleTunnel(w http.ResponseWriter, r *http.Request) {
vhost := r.URL.Query().Get("vhost")
if vhost == "" {
http.Error(w, "Missing vhost parameter", http.StatusBadRequest)
return
}
conn, err := s.upgrader.Upgrade(w, r, nil)
if err != nil {
log.Printf("WebSocket upgrade failed: %v", err)
return
}
tunnel := &TunnelConnection{
conn: conn,
vhost: vhost,
responses: make(map[string]chan *TunnelResponse),
}
s.mu.Lock()
s.tunnels[vhost] = tunnel
s.mu.Unlock()
log.Printf("Tunnel established: %s", vhost)
// Handle tunnel communication
s.handleTunnelConnection(tunnel)
}
func (s *Server) handleTunnelConnection(tunnel *TunnelConnection) {
defer func() {
s.mu.Lock()
delete(s.tunnels, tunnel.vhost)
s.mu.Unlock()
tunnel.conn.Close()
log.Printf("Tunnel closed: %s", tunnel.vhost)
}()
// Handle incoming responses from client
for {
var resp TunnelResponse
if err := tunnel.conn.ReadJSON(&resp); err != nil {
log.Printf("Error reading response from tunnel %s: %v", tunnel.vhost, err)
return
conn, err := listener.Accept()
if err != nil {
log.Printf("Error accepting connection: %v", err)
continue
}
// Find the response channel for this request
tunnel.mu.RLock()
respChan, exists := tunnel.responses[resp.ID]
tunnel.mu.RUnlock()
if exists {
select {
case respChan <- &resp:
// Response delivered
default:
log.Printf("Response channel full for request %s", resp.ID)
go s.handleRawConnection(conn)
}
} else {
log.Printf("No response channel found for request %s", resp.ID)
}
}
}
func (s *Server) handleStatus(w http.ResponseWriter, r *http.Request) {
s.mu.RLock()
defer s.mu.RUnlock()
w.Header().Set("Content-Type", "application/json")
fmt.Fprintf(w, `{"tunnels": %d, "active": [`, len(s.tunnels))
first := true
for vhost := range s.tunnels {
if !first {
fmt.Fprint(w, ",")
}
fmt.Fprintf(w, `{"vhost":"%s"}`, vhost)
first = false
}
fmt.Fprint(w, "]}")
}
func (s *Server) extractSubdomain(host string) string {
@ -235,3 +76,259 @@ func (s *Server) extractSubdomain(host string) string {
return ""
}
func (s *Server) handleStatus(conn net.Conn) {
s.mu.RLock()
count := len(s.tunnels)
s.mu.RUnlock()
response := fmt.Sprintf(
"HTTP/1.1 200 OK\r\n"+
"Content-Type: application/json\r\n"+
"Content-Length: %d\r\n\r\n"+
`{"tunnels": %d}`,
len(fmt.Sprintf(`{"tunnels": %d}`, count)), count)
conn.Write([]byte(response))
}
func (s *Server) extractHostFromHTTP(data []byte) string {
// Simple HTTP header parsing
lines := strings.Split(string(data), "\r\n")
for _, line := range lines {
if strings.HasPrefix(strings.ToLower(line), "host:") {
parts := strings.SplitN(line, ":", 2)
if len(parts) == 2 {
return strings.TrimSpace(parts[1])
}
}
}
return ""
}
func (s *Server) proxyRawConnection(clientConn net.Conn, tunnelConn *TunnelConnection, initialData []byte) {
defer clientConn.Close()
// Generate a unique stream ID for this connection
streamID := fmt.Sprintf("stream_%d", time.Now().UnixNano())
// Send initial data with stream ID
msg := TunnelMessage{
Type: "data",
StreamID: streamID,
Data: initialData,
}
if err := tunnelConn.WriteJSON(msg); err != nil {
log.Printf("Error sending initial data: %v", err)
return
}
// Create a channel for this stream's responses
responseChan := make(chan []byte, 100)
// Register this stream
s.mu.Lock()
if tunnelConn.streams == nil {
tunnelConn.streams = make(map[string]chan []byte)
}
tunnelConn.streams[streamID] = responseChan
s.mu.Unlock()
// Clean up when done
defer func() {
s.mu.Lock()
delete(tunnelConn.streams, streamID)
close(responseChan)
s.mu.Unlock()
// Send close message
closeMsg := TunnelMessage{
Type: "close",
StreamID: streamID,
}
tunnelConn.WriteJSON(closeMsg)
}()
// Handle client -> tunnel
go func() {
buffer := make([]byte, 4096)
for {
n, err := clientConn.Read(buffer)
if err != nil {
return
}
msg := TunnelMessage{
Type: "data",
StreamID: streamID,
Data: buffer[:n],
}
if err := tunnelConn.WriteJSON(msg); err != nil {
return
}
}
}()
// Handle tunnel -> client (read from response channel)
for data := range responseChan {
if _, err := clientConn.Write(data); err != nil {
break
}
}
}
func (s *Server) handleRawConnection(conn net.Conn) {
defer conn.Close()
// Read enough to get the Host header
buffer := make([]byte, 4096)
n, err := conn.Read(buffer)
if err != nil {
return
}
// Extract host
host := s.extractHostFromHTTP(buffer[:n])
subdomain := s.extractSubdomain(host)
// If we have a registered tunnel for this subdomain, relay it
if subdomain != "" {
s.mu.RLock()
tunnelConn, exists := s.tunnels[subdomain]
s.mu.RUnlock()
if exists {
log.Printf("Relaying %s to tunnel", subdomain)
s.proxyRawConnection(conn, tunnelConn, buffer[:n])
return
}
}
// Otherwise, handle as control server (recreate HTTP request and use net/http)
s.handleAsHTTP(conn, buffer[:n])
}
func (s *Server) handleAsHTTP(conn net.Conn, initialData []byte) {
// Create a fake HTTP request from the raw data
reader := bufio.NewReader(bytes.NewReader(initialData))
req, err := http.ReadRequest(reader)
if err != nil {
conn.Write([]byte("HTTP/1.1 400 Bad Request\r\n\r\n"))
return
}
// Handle control endpoints
if req.URL.Path == "/_conduit/tunnel" {
s.handleTunnelUpgrade(conn, req)
} else if req.URL.Path == "/_conduit/status" {
s.handleStatus(conn)
} else {
conn.Write([]byte("HTTP/1.1 404 Not Found\r\n\r\n"))
}
}
func (s *Server) handleTunnelMessages(tunnel *TunnelConnection) {
for {
var msg TunnelMessage
err := tunnel.ReadJSON(&msg)
if err != nil {
break
}
// Route message to appropriate stream
if msg.Type == "data" && msg.StreamID != "" {
s.mu.RLock()
if streamChan, exists := tunnel.streams[msg.StreamID]; exists {
select {
case streamChan <- msg.Data:
case <-time.After(time.Second):
log.Printf("Stream %s channel full, dropping data", msg.StreamID)
}
}
s.mu.RUnlock()
}
}
}
func (s *Server) handleTunnelUpgrade(conn net.Conn, req *http.Request) {
vhost := req.URL.Query().Get("vhost")
if vhost == "" {
conn.Write([]byte("HTTP/1.1 400 Bad Request\r\n\r\nMissing vhost parameter"))
return
}
// Create a fake ResponseWriter that writes to our raw connection
fakeWriter := &fakeResponseWriter{conn: conn}
// Use the upgrader
wsConn, err := s.upgrader.Upgrade(fakeWriter, req, nil)
if err != nil {
log.Printf("WebSocket upgrade failed: %v", err)
return
}
// Create TunnelConnection
tunnel := &TunnelConnection{
Conn: wsConn,
vhost: vhost,
streams: make(map[string]chan []byte),
}
s.mu.Lock()
s.tunnels[vhost] = tunnel
s.mu.Unlock()
log.Printf("Tunnel established: %s", vhost)
// Keep connection alive and handle cleanup
defer func() {
s.mu.Lock()
delete(s.tunnels, vhost)
s.mu.Unlock()
wsConn.Close()
log.Printf("Tunnel closed: %s", vhost)
}()
// Handle tunnel messages
s.handleTunnelMessages(tunnel)
}
type fakeResponseWriter struct {
conn net.Conn
header http.Header
}
func (f *fakeResponseWriter) Header() http.Header {
if f.header == nil {
f.header = make(http.Header)
}
return f.header
}
func (f *fakeResponseWriter) Write(data []byte) (int, error) {
return f.conn.Write(data)
}
func (f *fakeResponseWriter) WriteHeader(statusCode int) {
// Write HTTP status line
status := fmt.Sprintf("HTTP/1.1 %d %s\r\n", statusCode, http.StatusText(statusCode))
f.conn.Write([]byte(status))
// Write headers
for key, values := range f.header {
for _, value := range values {
f.conn.Write([]byte(fmt.Sprintf("%s: %s\r\n", key, value)))
}
}
// End headers
f.conn.Write([]byte("\r\n"))
}
// Implement http.Hijacker
func (f *fakeResponseWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
// Return the raw connection and create a ReadWriter for it
rw := bufio.NewReadWriter(bufio.NewReader(f.conn), bufio.NewWriter(f.conn))
return f.conn, rw, nil
}

45
server/tunnel.go Normal file
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@ -0,0 +1,45 @@
package server
import (
"bufio"
"fmt"
"net"
"net/http"
)
type tunnelWriter struct {
conn net.Conn
header http.Header
}
func (f *tunnelWriter) Header() http.Header {
if f.header == nil {
f.header = make(http.Header)
}
return f.header
}
func (f *tunnelWriter) Write(data []byte) (int, error) {
return f.conn.Write(data)
}
func (f *tunnelWriter) WriteHeader(statusCode int) {
// Write HTTP status line
status := fmt.Sprintf("HTTP/1.1 %d %s\r\n", statusCode, http.StatusText(statusCode))
f.conn.Write([]byte(status))
// Write headers
for key, values := range f.header {
for _, value := range values {
f.conn.Write([]byte(fmt.Sprintf("%s: %s\r\n", key, value)))
}
}
// End headers
f.conn.Write([]byte("\r\n"))
}
func (f *tunnelWriter) Hijack() (net.Conn, *bufio.ReadWriter, error) {
rw := bufio.NewReadWriter(bufio.NewReader(f.conn), bufio.NewWriter(f.conn))
return f.conn, rw, nil
}