new feature: assign a random port if remote_port is 0 in type tcp and

udp

server/dashboard.go

@@ -32,7 +32,7 @@ var (
 	httpServerWriteTimeout = 10 * time.Second
 )
 
-func RunDashboardServer(addr string, port int64) (err error) {
+func RunDashboardServer(addr string, port int) (err error) {
 	// url router
 	router := httprouter.New()
 

server/dashboard_api.go

@@ -36,8 +36,8 @@ type ServerInfoResp struct {
 	GeneralResponse
 
 	Version          string `json:"version"`
-	VhostHttpPort    int64  `json:"vhost_http_port"`
-	VhostHttpsPort   int64  `json:"vhost_https_port"`
+	VhostHttpPort    int    `json:"vhost_http_port"`
+	VhostHttpsPort   int    `json:"vhost_https_port"`
 	AuthTimeout      int64  `json:"auth_timeout"`
 	SubdomainHost    string `json:"subdomain_host"`
 	MaxPoolCount     int64  `json:"max_pool_count"`

server/ports.go

@@ -0,0 +1,180 @@
+package server
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"sync"
+	"time"
+)
+
+const (
+	MinPort                    = 1025
+	MaxPort                    = 65535
+	MaxPortReservedDuration    = time.Duration(24) * time.Hour
+	CleanReservedPortsInterval = time.Hour
+)
+
+var (
+	ErrPortAlreadyUsed = errors.New("port already used")
+	ErrPortNotAllowed  = errors.New("port not allowed")
+	ErrPortUnAvailable = errors.New("port unavailable")
+	ErrNoAvailablePort = errors.New("no available port")
+)
+
+type PortCtx struct {
+	ProxyName  string
+	Port       int
+	Closed     bool
+	UpdateTime time.Time
+}
+
+type PortManager struct {
+	reservedPorts map[string]*PortCtx
+	usedPorts     map[int]*PortCtx
+	freePorts     map[int]struct{}
+
+	bindAddr string
+	netType  string
+	mu       sync.Mutex
+}
+
+func NewPortManager(netType string, bindAddr string, allowPorts map[int]struct{}) *PortManager {
+	pm := &PortManager{
+		reservedPorts: make(map[string]*PortCtx),
+		usedPorts:     make(map[int]*PortCtx),
+		freePorts:     make(map[int]struct{}),
+		bindAddr:      bindAddr,
+		netType:       netType,
+	}
+	if len(allowPorts) > 0 {
+		for port, _ := range allowPorts {
+			pm.freePorts[port] = struct{}{}
+		}
+	} else {
+		for i := MinPort; i <= MaxPort; i++ {
+			pm.freePorts[i] = struct{}{}
+		}
+	}
+	go pm.cleanReservedPortsWorker()
+	return pm
+}
+
+func (pm *PortManager) Acquire(name string, port int) (realPort int, err error) {
+	portCtx := &PortCtx{
+		ProxyName:  name,
+		Closed:     false,
+		UpdateTime: time.Now(),
+	}
+
+	var ok bool
+
+	pm.mu.Lock()
+	defer func() {
+		if err == nil {
+			portCtx.Port = realPort
+		}
+		pm.mu.Unlock()
+	}()
+
+	// check reserved ports first
+	if port == 0 {
+		if ctx, ok := pm.reservedPorts[name]; ok {
+			if pm.isPortAvailable(ctx.Port) {
+				realPort = ctx.Port
+				pm.usedPorts[realPort] = portCtx
+				pm.reservedPorts[name] = portCtx
+				delete(pm.freePorts, realPort)
+				return
+			}
+		}
+	}
+
+	if port == 0 {
+		// get random port
+		count := 0
+		maxTryTimes := 5
+		for k, _ := range pm.freePorts {
+			count++
+			if count > maxTryTimes {
+				break
+			}
+			if pm.isPortAvailable(k) {
+				realPort = k
+				pm.usedPorts[realPort] = portCtx
+				pm.reservedPorts[name] = portCtx
+				delete(pm.freePorts, realPort)
+				break
+			}
+		}
+		if realPort == 0 {
+			err = ErrNoAvailablePort
+		}
+	} else {
+		// specified port
+		if _, ok = pm.freePorts[port]; ok {
+			if pm.isPortAvailable(port) {
+				realPort = port
+				pm.usedPorts[realPort] = portCtx
+				pm.reservedPorts[name] = portCtx
+				delete(pm.freePorts, realPort)
+			} else {
+				err = ErrPortUnAvailable
+			}
+		} else {
+			if _, ok = pm.usedPorts[port]; ok {
+				err = ErrPortAlreadyUsed
+			} else {
+				err = ErrPortNotAllowed
+			}
+		}
+	}
+	return
+}
+
+func (pm *PortManager) isPortAvailable(port int) bool {
+	if pm.netType == "udp" {
+		addr, err := net.ResolveUDPAddr("udp", fmt.Sprintf("%s:%d", pm.bindAddr, port))
+		if err != nil {
+			return false
+		}
+		l, err := net.ListenUDP("udp", addr)
+		if err != nil {
+			return false
+		}
+		l.Close()
+		return true
+	} else {
+		l, err := net.Listen(pm.netType, fmt.Sprintf("%s:%d", pm.bindAddr, port))
+		if err != nil {
+			return false
+		}
+		l.Close()
+		return true
+	}
+}
+
+func (pm *PortManager) Release(port int) {
+	pm.mu.Lock()
+	defer pm.mu.Unlock()
+	if ctx, ok := pm.usedPorts[port]; ok {
+		pm.freePorts[port] = struct{}{}
+		delete(pm.usedPorts, port)
+		ctx.Closed = true
+		ctx.UpdateTime = time.Now()
+	}
+}
+
+// Release reserved port if it isn't used in last 24 hours.
+func (pm *PortManager) cleanReservedPortsWorker() {
+	for {
+		time.Sleep(CleanReservedPortsInterval)
+		pm.mu.Lock()
+		for name, ctx := range pm.reservedPorts {
+			if ctx.Closed && time.Since(ctx.UpdateTime) > MaxPortReservedDuration {
+				delete(pm.reservedPorts, name)
+			}
+		}
+		pm.mu.Unlock()
+	}
+}

server/proxy.go

@@ -165,11 +165,24 @@ func NewProxy(ctl *Control, pxyConf config.ProxyConf) (pxy Proxy, err error) {
 type TcpProxy struct {
 	BaseProxy
 	cfg *config.TcpProxyConf
+
+	realPort int
 }
 
 func (pxy *TcpProxy) Run() (remoteAddr string, err error) {
-	remoteAddr = fmt.Sprintf(":%d", pxy.cfg.RemotePort)
-	listener, errRet := frpNet.ListenTcp(config.ServerCommonCfg.ProxyBindAddr, pxy.cfg.RemotePort)
+	pxy.realPort, err = pxy.ctl.svr.tcpPortManager.Acquire(pxy.name, pxy.cfg.RemotePort)
+	if err != nil {
+		return
+	}
+	defer func() {
+		if err != nil {
+			pxy.ctl.svr.tcpPortManager.Release(pxy.realPort)
+		}
+	}()
+
+	remoteAddr = fmt.Sprintf(":%d", pxy.realPort)
+	pxy.cfg.RemotePort = pxy.realPort
+	listener, errRet := frpNet.ListenTcp(config.ServerCommonCfg.ProxyBindAddr, pxy.realPort)
 	if errRet != nil {
 		err = errRet
 		return
@@ -188,6 +201,7 @@ func (pxy *TcpProxy) GetConf() config.ProxyConf {
 
 func (pxy *TcpProxy) Close() {
 	pxy.BaseProxy.Close()
+	pxy.ctl.svr.tcpPortManager.Release(pxy.realPort)
 }
 
 type HttpProxy struct {
@@ -412,6 +426,8 @@ type UdpProxy struct {
 	BaseProxy
 	cfg *config.UdpProxyConf
 
+	realPort int
+
 	// udpConn is the listener of udp packages
 	udpConn *net.UDPConn
 
@@ -432,8 +448,19 @@ type UdpProxy struct {
 }
 
 func (pxy *UdpProxy) Run() (remoteAddr string, err error) {
-	remoteAddr = fmt.Sprintf(":%d", pxy.cfg.RemotePort)
-	addr, errRet := net.ResolveUDPAddr("udp", fmt.Sprintf("%s:%d", config.ServerCommonCfg.ProxyBindAddr, pxy.cfg.RemotePort))
+	pxy.realPort, err = pxy.ctl.svr.udpPortManager.Acquire(pxy.name, pxy.cfg.RemotePort)
+	if err != nil {
+		return
+	}
+	defer func() {
+		if err != nil {
+			pxy.ctl.svr.udpPortManager.Release(pxy.realPort)
+		}
+	}()
+
+	remoteAddr = fmt.Sprintf(":%d", pxy.realPort)
+	pxy.cfg.RemotePort = pxy.realPort
+	addr, errRet := net.ResolveUDPAddr("udp", fmt.Sprintf("%s:%d", config.ServerCommonCfg.ProxyBindAddr, pxy.realPort))
 	if errRet != nil {
 		err = errRet
 		return
@@ -581,6 +608,7 @@ func (pxy *UdpProxy) Close() {
 		close(pxy.readCh)
 		close(pxy.sendCh)
 	}
+	pxy.ctl.svr.udpPortManager.Release(pxy.realPort)
 }
 
 // HandleUserTcpConnection is used for incoming tcp user connections.

server/service.go

@@ -60,17 +60,25 @@ type Service struct {
 	// Manage all visitor listeners.
 	visitorManager *VisitorManager
 
+	// Manage all tcp ports.
+	tcpPortManager *PortManager
+
+	// Manage all udp ports.
+	udpPortManager *PortManager
+
 	// Controller for nat hole connections.
 	natHoleController *NatHoleController
 }
 
 func NewService() (svr *Service, err error) {
+	cfg := config.ServerCommonCfg
 	svr = &Service{
 		ctlManager:     NewControlManager(),
 		pxyManager:     NewProxyManager(),
 		visitorManager: NewVisitorManager(),
+		tcpPortManager: NewPortManager("tcp", cfg.ProxyBindAddr, cfg.PrivilegeAllowPorts),
+		udpPortManager: NewPortManager("udp", cfg.ProxyBindAddr, cfg.PrivilegeAllowPorts),
 	}
-	cfg := config.ServerCommonCfg
 
 	// Init assets.
 	err = assets.Load(cfg.AssetsDir)