目前我做测试想做一个特殊的转发,A 代码运行在公网监听两个端口,一个是用户请求;另一个是 B 代码的请求连接。A 接受到请求后将用户的请求转发到 B ,目前表象一直卡在了 B 回传回去的问题上(没有对 B 请求成功是否验证),请问各位大佬,这个如何操作
A 代码如下
package main
import (
"fmt"
"io"
"net"
"sync"
)
var (
bConnMu sync.Mutex
bConn net.Conn
)
func handleUserRequest(userConn net.Conn) {
defer func() {
userConn.Close()
fmt.Println("User connection closed")
}()
fmt.Println("Received user request")
bConnMu.Lock()
if bConn == nil {
bConnMu.Unlock()
fmt.Println("No connection to B machine")
fmt.Fprintln(userConn, "No connection to B machine")
return
}
bConnMu.Unlock()
fmt.Println("Forwarding request to B machine")
// 将用户请求转发给 B 机器
err := forwardRequest(userConn, bConn)
if err != nil {
fmt.Println("Error forwarding request to B machine:", err)
return
}
fmt.Println("User request completed")
}
func forwardRequest(userConn, bConn net.Conn) error {
done := make(chan error, 1)
// 将用户请求转发给 B 机器
go func() {
_, err := io.Copy(bConn, userConn)
if err != nil {
fmt.Println("Error forwarding request to B machine:", err)
} else {
fmt.Println("Finished forwarding request to B machine")
}
done <- err
}()
// 将 B 机器的响应转发给用户
go func() {
_, err := io.Copy(userConn, bConn)
if err != nil {
fmt.Println("Error forwarding response to user:", err)
} else {
fmt.Println("Finished forwarding response to user")
}
done <- err
}()
err := <-done
if err != nil {
return err
}
err = <-done
return err
}
func handleBConnection(conn net.Conn) {
fmt.Println("B machine connected")
bConnMu.Lock()
if bConn != nil {
bConn.Close()
fmt.Println("Closed previous connection to B machine")
}
bConn = conn
bConnMu.Unlock()
// 监听 B 机器的断开连接
_, err := io.Copy(io.Discard, conn)
if err != nil {
fmt.Println("B machine disconnected with error:", err)
} else {
fmt.Println("B machine disconnected")
}
bConnMu.Lock()
if bConn == conn {
bConn = nil
fmt.Println("Removed connection to B machine")
}
bConnMu.Unlock()
conn.Close()
}
func main11() {
// 启动监听用户代理请求的 goroutine
fmt.Println("A machine listening for user requests on :12345")
go func() {
listener, err := net.Listen("tcp", ":12345")
if err != nil {
fmt.Println("Failed to listen for user requests:", err)
return
}
defer listener.Close()
for {
conn, err := listener.Accept()
if err != nil {
fmt.Println("Failed to accept user request:", err)
continue
}
go handleUserRequest(conn)
}
}()
// 启动监听 B 机器连接的 goroutine
fmt.Println("A machine listening for B machine connection on :12346")
listener, err := net.Listen("tcp", ":12346")
if err != nil {
fmt.Println("Failed to listen for B machine connection:", err)
return
}
defer listener.Close()
for {
conn, err := listener.Accept()
if err != nil {
fmt.Println("Failed to accept B machine connection:", err)
continue
}
go handleBConnection(conn)
}
}
B 代码如下
package main
import (
"bufio"
"fmt"
"io"
"log"
"net"
"net/http"
"time"
)
func handleTunnel(conn net.Conn) {
defer func() {
conn.Close()
fmt.Println("Tunnel connection closed")
}()
fmt.Println("Handling new tunnel connection")
reader := bufio.NewReader(conn)
for {
conn.SetReadDeadline(time.Now().Add(30 * time.Second))
request, err := http.ReadRequest(reader)
if err != nil {
if err == io.EOF {
fmt.Println("A machine closed the connection")
return
}
fmt.Println("Error reading request:", err)
return
}
fmt.Printf("Received request from A machine: %s %s\n", request.Method, request.URL)
if request.Method == http.MethodConnect {
fmt.Printf("Processing CONNECT request: %s\n", request.URL.Host)
targetConn, err := net.DialTimeout("tcp", request.URL.Host, 10*time.Second)
if err != nil {
log.Printf("Error connecting to target: %v\n", err)
// 修改这里来手动发送 HTTP 响应
conn.Write([]byte("HTTP/1.1 503 Service Unavailable\r\n\r\n"))
return
}
conn.Write([]byte("HTTP/1.1 200 Connection Established\r\n\r\n"))
// 设置通道同步 goroutines
done := make(chan struct{})
// 开启 goroutine 处理从 client 到目标主机的流量
go func() {
io.Copy(targetConn, conn) // 假设 conn 是从 net.Listen 获取的连接
close(done)
}()
// 开启 goroutine 处理从目标主机到 client 的流量
go func() {
io.Copy(conn, targetConn)
close(done)
}()
// 等待至少一个方向的流完成
<-done
targetConn.Close()
conn.Close()
} else {
fmt.Printf("Processing normal request: %s\n", request.URL)
// 处理普通请求
targetConn, err := net.DialTimeout("tcp", request.Host, 10*time.Second)
if err != nil {
fmt.Println("Error connecting to target host:", err)
conn.Write([]byte("HTTP/1.1 503 Service Unavailable\r\n\r\n"))
continue
}
defer func() {
targetConn.Close()
fmt.Printf("Target connection to %s closed\n", request.Host)
}()
fmt.Println("Connected to target host:", request.Host)
// 将请求转发给目标主机
err = request.Write(targetConn)
if err != nil {
fmt.Println("Error forwarding request to target host:", err)
conn.Write([]byte("HTTP/1.1 503 Service Unavailable\r\n\r\n"))
continue
}
fmt.Println("Forwarded request to target host")
// 将目标主机的响应转发给 A 机器
response, err := http.ReadResponse(bufio.NewReader(targetConn), request)
if err != nil {
fmt.Println("Error reading response from target host:", err)
conn.Write([]byte("HTTP/1.1 503 Service Unavailable\r\n\r\n"))
continue
}
fmt.Println("Read response from target host")
err = response.Write(conn)
if err != nil {
fmt.Println("Error forwarding response to A machine:", err)
continue
}
fmt.Println("Forwarded response to A machine")
}
}
}
func connectToA() {
for {
fmt.Println("Attempting to connect to A machine")
conn, err := net.Dial("tcp", "A 机器地址:12346")
if err != nil {
fmt.Println("Failed to connect to A machine:", err)
time.Sleep(5 * time.Second)
continue
}
fmt.Println("Connected to A machine")
// 发送心跳包
go func() {
for {
_, err := conn.Write([]byte("ping"))
if err != nil {
fmt.Println("Failed to send heartbeat:", err)
conn.Close()
return
}
time.Sleep(5 * time.Second)
}
}()
handleTunnel(conn)
}
}
func main() {
go connectToA()
select {} // 阻塞主线程
}
1
mango88 154 天前
// 监听 B 机器的断开连接
_, err := io.Copy(io.Discard, conn) 这里占用了 socket 的输入流 |
2
lifei6671 154 天前 2
你这代码写的槽点太多了。首先你要理解,
1 、读写 net.Conn 必须独占不能共享。 2 、go 启动的协程必须有退出的时机,否则就会协程泄漏。 3 、chan 是不能多次 close 的,否则会 panic 。 4 、等待多个协程退出后继续执行,建议使用 sync.WaitGroup |
3
xxxccc 154 天前
感觉你想要写一个 tcp proxy ,简单看了下代码,有很多奇怪的地方。建议你先让 chatgpt 帮你写一个 golang 的 tcp proxy
|
4
lt0136 154 天前
梳理一下你的需求:
B 的作用是 HTTP 代理,A 的作用是公网转发请求到 B 这个不需要自己写啊,B 启动一个的 HTTP 代理( squid ),再用内网穿透工具比如 frp 之类的把 B 的代理端口映射到 A 就好了 |
6
gochat 153 天前
1 ,A minimalist port forward tool By Java
https://github.com/LockGit/portforward 2 ,实现 socks5 代理来访问看上去不能访问的资源 https://github.com/LockGit/Go?tab=readme-ov-file#%E5%AE%9E%E7%8E%B0socks5%E4%BB%A3%E7%90%86%E6%9D%A5%E8%AE%BF%E9%97%AE%E7%9C%8B%E4%B8%8A%E5%8E%BB%E4%B8%8D%E8%83%BD%E8%AE%BF%E9%97%AE%E7%9A%84%E8%B5%84%E6%BA%90 这 2 个你都可以参考 |