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增加http代理的功能
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dushixiang committed Nov 18, 2020
1 parent 897b86e commit 2727e9a
Showing 1 changed file with 91 additions and 12 deletions.
103 changes: 91 additions & 12 deletions 4dnat.go
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Original file line number Diff line number Diff line change
@@ -1,16 +1,19 @@
package main

import (
"crypto/tls"
"io"
"log"
"net"
"net/http"
"os"
"strings"
"sync"
"time"
)

const RetryInterval int = 5
const Timeout int = 10

func init() {
log.SetPrefix("[4dnat] ")
Expand All @@ -32,6 +35,8 @@ func main() {
forward(args[2], args[3])
case "-agent", "-a":
agent(args[2], args[3])
case "-proxy", "-p":
proxy(args[2], args[3], args)
default:
printHelp()
}
Expand All @@ -42,6 +47,7 @@ func printHelp() {
println(` "-forward listenPort targetAddress" example: "-forward 10000 127.0.0.1:22"`)
println(` "-listen listenPort0 listenPort1" example: "-listen 10000 10001"`)
println(` "-agent targetAddress0 targetAddress1" example: "-agent 127.0.0.1:10000 127.0.0.1:22"`)
println(` "-proxy protocol listenAddress" example: "-proxy http 1080", "-proxy https 1080 server.pem server.key"`)
}

func printBanner() {
Expand All @@ -57,7 +63,7 @@ func printBanner() {

func copyIO(src, dest net.Conn, wg *sync.WaitGroup) {
defer src.Close()
log.Printf("[#] [%s->%s] ==> [%s->%s]\n", src.RemoteAddr().String(), src.LocalAddr().String(), dest.LocalAddr().String(), dest.RemoteAddr().String())
log.Printf("[*] [%s->%s] ==> [%s->%s]\n", src.RemoteAddr().String(), src.LocalAddr().String(), dest.LocalAddr().String(), dest.RemoteAddr().String())
_, _ = io.Copy(src, dest)
log.Printf("[-] [%s->%s] closed.\n", src.RemoteAddr().String(), src.LocalAddr().String())
wg.Done()
Expand All @@ -66,7 +72,7 @@ func copyIO(src, dest net.Conn, wg *sync.WaitGroup) {
func listener(listenPort0, listenPort1 string) {
ln0 := listen(listenPort0)
ln1 := listen(listenPort1)
log.Printf("[#] listen port on: [%s %s],[%s %s]\n", ln0.Addr().Network(), ln0.Addr().String(), ln1.Addr().Network(), ln1.Addr().String())
log.Printf("[*] listen port on: [%s %s],[%s %s]\n", ln0.Addr().Network(), ln0.Addr().String(), ln1.Addr().Network(), ln1.Addr().String())

for true {
cc := make(chan net.Conn, 2)
Expand All @@ -81,7 +87,7 @@ func listener(listenPort0, listenPort1 string) {

func forward(listenPort string, targetAddress string) {
ln := listen(listenPort)
log.Printf("[#] listen on: [%s %s] forward to: [%s]\n", ln.Addr().Network(), ln.Addr().String(), targetAddress)
log.Printf("[*] listen on: [%s %s] forward to: [%s]\n", ln.Addr().Network(), ln.Addr().String(), targetAddress)
for true {
cc := make(chan net.Conn, 2)

Expand All @@ -95,7 +101,7 @@ func forward(listenPort string, targetAddress string) {
}

func agent(targetAddress0 string, targetAddress1 string) {
log.Printf("[#] agent with: [%s %s]\n", targetAddress0, targetAddress1)
log.Printf("[*] agent with: [%s %s]\n", targetAddress0, targetAddress1)
for {
cc := make(chan net.Conn, 2)

Expand All @@ -117,28 +123,28 @@ func mutualCopyIO(conn0, conn1 net.Conn) {

func dial(cc chan net.Conn, targetAddress string) {
for true {
conn, err := net.Dial("tcp", targetAddress)
conn, err := net.DialTimeout("tcp", targetAddress, time.Duration(Timeout)*time.Second)
if err != nil {
log.Printf("[x] connect [%s] error [%s].\n", targetAddress, err.Error())
log.Printf("[#] retry to connect: [%s] after [%d] second\n", targetAddress, RetryInterval)
log.Printf("[x] connect [%s] error [%s]\n", targetAddress, err.Error())
log.Printf("[*] retry to connect: [%s] after [%d] second\n", targetAddress, RetryInterval)
time.Sleep(time.Duration(RetryInterval) * time.Second)
continue
}
log.Printf("[+] [%s->%s] connected to target.\n", conn.LocalAddr().String(), targetAddress)
log.Printf("[+] [%s->%s] connected to target\n", conn.LocalAddr().String(), targetAddress)
cc <- conn
break
}
}

func accept(cc chan net.Conn, ln net.Listener) {
for true {
log.Printf("[#] waiting for client to connect [%s %s]\n", ln.Addr().Network(), ln.Addr().String())
log.Printf("[*] waiting for client to connect [%s %s]\n", ln.Addr().Network(), ln.Addr().String())
c, err := ln.Accept()
if err != nil {
log.Printf("[x] accept error [%s].\n", err.Error())
log.Printf("[x] accept error [%s]\n", err.Error())
continue
}
log.Printf("[+] [%s<-%s] new client connected.\n", c.LocalAddr().String(), c.RemoteAddr().String())
log.Printf("[+] [%s<-%s] new client connected\n", c.LocalAddr().String(), c.RemoteAddr().String())
cc <- c
break
}
Expand All @@ -150,8 +156,81 @@ func listen(listenPort string) net.Listener {
}
ln, err := net.Listen("tcp", listenPort)
if err != nil {
log.Printf("[x] listen error [%s].\n", err.Error())
log.Printf("[x] listen error [%s]\n", err.Error())
os.Exit(0)
}
return ln
}

func proxy(protocol, listenAddress string, args []string) {
if protocol != "http" && protocol != "https" {
log.Fatal("protocol must be either http or https")
}

if !strings.Contains(listenAddress, ":") {
listenAddress = "0.0.0.0:" + listenAddress
}

server := &http.Server{
Addr: listenAddress,
Handler: http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if r.Method == http.MethodConnect {
handleWebSocket(w, r)
} else {
handleHttp(w, r)
}
}),
TLSNextProto: make(map[string]func(*http.Server, *tls.Conn, http.Handler)),
}

if protocol == "https" {
if len(args) < 6 {
printHelp()
os.Exit(0)
}
certFile := args[5]
keyFile := args[6]
log.Printf("[*] https proxy listen on: [%s] with cert: [%s] and key: [%s]", listenAddress, certFile, keyFile)
log.Fatal(server.ListenAndServeTLS(certFile, keyFile))
} else {
log.Printf("[*] http proxy listen on: [%s]", listenAddress)
log.Fatal(server.ListenAndServe())
}
}

func handleWebSocket(w http.ResponseWriter, r *http.Request) {
remoteConn, err := net.DialTimeout("tcp", r.Host, time.Duration(Timeout)*time.Second)
if err != nil {
http.Error(w, err.Error(), http.StatusServiceUnavailable)
return
}
w.WriteHeader(http.StatusOK)
hijacker, ok := w.(http.Hijacker)
if !ok {
http.Error(w, "hijack not supported", http.StatusInternalServerError)
return
}
centralConn, _, err := hijacker.Hijack()
if err != nil {
http.Error(w, err.Error(), http.StatusServiceUnavailable)
}

go mutualCopyIO(remoteConn, centralConn)
}

func handleHttp(w http.ResponseWriter, req *http.Request) {
resp, err := http.DefaultTransport.RoundTrip(req)
if err != nil {
http.Error(w, err.Error(), http.StatusServiceUnavailable)
return
}
defer resp.Body.Close()

for k, vv := range resp.Header {
for _, v := range vv {
w.Header().Add(k, v)
}
}
w.WriteHeader(resp.StatusCode)
_, _ = io.Copy(w, resp.Body)
}

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