dont close until they close themself

config.go

@@ -15,6 +15,8 @@ type Config struct {
 	TLSInsecure bool
 	Limiter     *rate.Limiter
 	DNS         string
+	TCPProxy    string
+	TCPProxyTLS bool
 }
 
 func NewConfig() *Config {
@@ -23,9 +25,11 @@ func NewConfig() *Config {
 	as.Append(args.INT, "p", "port to listen on", 61113)
 	as.Append(args.INT, "kbps", "kilobytes per sec limit", -1)
 	as.Append(args.BOOL, "tls-insecure", "permit tls insecure", false)
+	as.Append(args.BOOL, "tcp-proxy-tls", "tcp proxy uses tls", true)
 	as.Append(args.DURATION, "t", "timeout", time.Minute)
 
 	as.Append(args.STRING, "dns", "dns ip:port", "1.1.1.1:53")
+	as.Append(args.STRING, "tcp-proxy", "host:port to tcp proxy to instead", "")
 
 	if err := as.Parse(); err != nil {
 		panic(err)
@@ -43,5 +47,7 @@ func NewConfig() *Config {
 		TLSInsecure: as.GetBool("tls-insecure"),
 		Limiter:     limiter,
 		DNS:         as.GetString("dns"),
+		TCPProxy:    as.GetString("tcp-proxy"),
+		TCPProxyTLS: as.GetBool("tcp-proxy-tls"),
 	}
 }

go.mod

@@ -7,6 +7,10 @@ require (
 	local/args v0.0.0-00010101000000-000000000000
 )
 
-require gopkg.in/yaml.v2 v2.4.0 // indirect
+require (
+	github.com/armon/go-socks5 v0.0.0-20160902184237-e75332964ef5 // indirect
+	golang.org/x/net v0.9.0 // indirect
+	gopkg.in/yaml.v2 v2.4.0 // indirect
+)
 
 replace local/args => ../../local/args

go.sum

@@ -1,3 +1,7 @@
+github.com/armon/go-socks5 v0.0.0-20160902184237-e75332964ef5 h1:0CwZNZbxp69SHPdPJAN/hZIm0C4OItdklCFmMRWYpio=
+github.com/armon/go-socks5 v0.0.0-20160902184237-e75332964ef5/go.mod h1:wHh0iHkYZB8zMSxRWpUBQtwG5a7fFgvEO+odwuTv2gs=
+golang.org/x/net v0.9.0 h1:aWJ/m6xSmxWBx+V0XRHTlrYrPG56jKsLdTFmsSsCzOM=
+golang.org/x/net v0.9.0/go.mod h1:d48xBJpPfHeWQsugry2m+kC02ZBRGRgulfHnEXEuWns=
 golang.org/x/time v0.0.0-20220722155302-e5dcc9cfc0b9 h1:ftMN5LMiBFjbzleLqtoBZk7KdJwhuybIU+FckUHgoyQ=
 golang.org/x/time v0.0.0-20220722155302-e5dcc9cfc0b9/go.mod h1:tRJNPiyCQ0inRvYxbN9jk5I+vvW/OXSQhTDSoE431IQ=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=

main.go

@@ -7,10 +7,17 @@ import (
 
 func main() {
 	config := NewConfig()
-	server := NewServer(config)
-
 	log.Printf("config: %+v", *config)
+
+	if config.TCPProxy != "" {
+		server := NewTCPServer(config)
+		if err := server.Listen(); err != nil {
+			panic(err)
+		}
+	} else {
+		server := NewServer(config)
 		if err := http.ListenAndServe(config.Listen, server); err != nil {
 			panic(err)
 		}
+	}
 }

server.go

@@ -10,6 +10,7 @@ import (
 	"net"
 	"net/http"
 	"strings"
+	"sync"
 	"time"
 
 	"golang.org/x/time/rate"
@@ -20,7 +21,22 @@ type Server struct {
 	resolver     *net.Resolver
 	limiter      *rate.Limiter
 	Timeout      time.Duration
-	dnsCache  map[string]string
+	dnsCacheLock sync.Mutex
+	dnsCache     map[string]dns
+}
+
+type dns struct {
+	result string
+	err    error
+	ts     time.Time
+}
+
+func (dns dns) ok() bool {
+	dur := time.Minute * 10
+	if dns.err != nil {
+		dur = time.Minute * 1
+	}
+	return time.Since(dns.ts) < dur
 }
 
 func NewServer(c *Config) *Server {
@@ -28,11 +44,11 @@ func NewServer(c *Config) *Server {
 		PreferGo: true,
 		Dial: func(ctx context.Context, network, addr string) (net.Conn, error) {
 			d := net.Dialer{Timeout: c.Timeout}
-			return d.DialContext(ctx, network, c.DNS)
-		},
+			if c.DNS != "" {
+				addr = c.DNS
 			}
-	if c.DNS == "" {
-		resolver = &net.Resolver{}
+			return d.DialContext(ctx, network, addr)
+		},
 	}
 	transport := &http.Transport{}
 	transport.TLSClientConfig = &tls.Config{
@@ -43,7 +59,7 @@ func NewServer(c *Config) *Server {
 		Transport: transport,
 		Timeout:   c.Timeout,
 		resolver:  resolver,
-		dnsCache:  map[string]string{},
+		dnsCache:  map[string]dns{},
 	}
 	transport.DialContext = func(ctx context.Context, network, addr string) (net.Conn, error) {
 		addr, err := s.dig(ctx, addr)
@@ -84,12 +100,18 @@ func (s *Server) Connect(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	dest, err := net.DialTimeout("tcp", host, s.Timeout)
+	network := "tcp"
+	if n := strings.Count(host, ":"); n > 3 {
+		network = "tcp6"
+	}
+	dest, err := net.DialTimeout(network, host, s.Timeout)
 	if err != nil {
 		s.Error(r, w, fmt.Errorf("error dialing w timeout %s=>%s: %w", r.Host, host, err))
 		return
 	}
 
+	w.WriteHeader(http.StatusOK)
+
 	client, _, err := hijacker.Hijack()
 	if err != nil {
 		s.Error(r, w, err)
@@ -134,8 +156,10 @@ func (s *Server) dig(ctx context.Context, host string) (string, error) {
 	search := host
 	search = strings.TrimPrefix(search, "https://")
 	search = strings.TrimPrefix(search, "http://")
-	if v, ok := s.dnsCache[host]; ok {
-		return v, nil
+	s.dnsCacheLock.Lock()
+	defer s.dnsCacheLock.Unlock()
+	if v, ok := s.dnsCache[host]; ok && v.ok() {
+		return v.result, v.err
 	}
 	port := ""
 	if splithost, splitport, err := net.SplitHostPort(host); err == nil {
@@ -143,14 +167,13 @@ func (s *Server) dig(ctx context.Context, host string) (string, error) {
 		port = ":" + splitport
 	}
 	ip, err := s.resolver.LookupHost(ctx, search)
-	if err != nil {
+	result := ""
+	if len(ip) > 0 {
+		result = strings.TrimPrefix(ip[0], "//") + port
+	}
+	s.dnsCache[host] = dns{result: result, err: err, ts: time.Now()}
+	if err != nil || result == "" {
 		return "", fmt.Errorf("failed to dns lookup %s: %v", search, err)
 	}
-	if len(ip) == 0 {
-		return "", errors.New("name does not resolve")
-	}
-	result := strings.TrimPrefix(ip[0], "//") + port
-	s.dnsCache[host] = result
-	//log.Printf("dug %s => %s => %s", host, search, result)
 	return result, nil
 }

tcp.go

@@ -0,0 +1,61 @@
+package main
+
+import (
+	"crypto/tls"
+	"io"
+	"log"
+	"net"
+)
+
+type TCP struct {
+	config *Config
+}
+
+func NewTCPServer(c *Config) TCP {
+	return TCP{config: c}
+}
+
+func (tcp TCP) Listen() error {
+	ln, err := net.Listen("tcp", tcp.config.Listen)
+	if err != nil {
+		return err
+	}
+	defer ln.Close()
+
+	log.Println("accepting tcp on", tcp.config.Listen)
+	for {
+		conn, err := ln.Accept()
+		if err != nil {
+			return err
+		}
+		go func() {
+			defer conn.Close()
+
+			conn2, err := func() (net.Conn, error) {
+				if tcp.config.TCPProxyTLS {
+					return tls.Dial("tcp", tcp.config.TCPProxy, &tls.Config{})
+				}
+				return net.Dial("tcp", tcp.config.TCPProxy)
+			}()
+			if err != nil {
+				log.Println(err)
+				return
+			}
+			defer conn2.Close()
+
+			errc := make(chan error)
+			go func() {
+				_, err := io.Copy(conn, conn2)
+				errc <- err
+			}()
+			go func() {
+				_, err := io.Copy(conn2, conn)
+				errc <- err
+			}()
+			for i := 0; i < 2; i++ {
+				<-errc
+			}
+			close(errc)
+		}()
+	}
+}