ssh: fixed an issue for unreachable addrs (fix #324)

README.md

@@ -449,14 +449,14 @@ glider -config CONFIG_PATH
       -v /etc/localtime:/etc/localtime:ro \
       nadoo/glider -config=/etc/glider/glider.conf
     ```
-  - run watchtower (if you need auto update for glider)
+  - run watchtower if you need auto update
     ```
     docker run -d --name watchtower --restart=always \
       -v /var/run/docker.sock:/var/run/docker.sock \
       containrrr/watchtower --interval 21600 --cleanup \
       glider
     ```
-  - open udp ports (if you need udp nat fullcone)
+  - open udp ports if you need udp nat fullcone
     ```
     iptables -I INPUT -p udp -m udp --dport 1024:65535 -j ACCEPT
     ```

go.mod

@@ -7,12 +7,12 @@ require (
 	github.com/dgryski/go-camellia v0.0.0-20191119043421-69a8a13fb23d
 	github.com/dgryski/go-idea v0.0.0-20170306091226-d2fb45a411fb
 	github.com/dgryski/go-rc2 v0.0.0-20150621095337-8a9021637152
-	github.com/insomniacslk/dhcp v0.0.0-20220405050111-12fbdcb11b41
+	github.com/insomniacslk/dhcp v0.0.0-20220504074936-1ca156eafb9f
 	github.com/nadoo/conflag v0.3.1
 	github.com/nadoo/ipset v0.5.0
 	github.com/xtaci/kcp-go/v5 v5.6.1
 	golang.org/x/crypto v0.0.0-20220427172511-eb4f295cb31f
-	golang.org/x/sys v0.0.0-20220502124256-b6088ccd6cba
+	golang.org/x/sys v0.0.0-20220503163025-988cb79eb6c6
 )
 
 require (

go.sum

@@ -39,8 +39,8 @@ github.com/google/go-cmp v0.5.6/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/
 github.com/google/go-cmp v0.5.7/go.mod h1:n+brtR0CgQNWTVd5ZUFpTBC8YFBDLK/h/bpaJ8/DtOE=
 github.com/gopherjs/gopherjs v0.0.0-20181017120253-0766667cb4d1/go.mod h1:wJfORRmW1u3UXTncJ5qlYoELFm8eSnnEO6hX4iZ3EWY=
 github.com/hugelgupf/socketpair v0.0.0-20190730060125-05d35a94e714/go.mod h1:2Goc3h8EklBH5mspfHFxBnEoURQCGzQQH1ga9Myjvis=
-github.com/insomniacslk/dhcp v0.0.0-20220405050111-12fbdcb11b41 h1:Yg3n3AI7GoHnWt7dyjsLPU+TEuZfPAg0OdiA3MJUV6I=
+github.com/insomniacslk/dhcp v0.0.0-20220504074936-1ca156eafb9f h1:l1QCwn715k8nYkj4Ql50rzEog3WnMdrd4YYMMwemxEo=
-github.com/insomniacslk/dhcp v0.0.0-20220405050111-12fbdcb11b41/go.mod h1:h+MxyHxRg9NH3terB1nfRIUaQEcI0XOVkdR9LNBlp8E=
+github.com/insomniacslk/dhcp v0.0.0-20220504074936-1ca156eafb9f/go.mod h1:h+MxyHxRg9NH3terB1nfRIUaQEcI0XOVkdR9LNBlp8E=
 github.com/josharian/native v1.0.0 h1:Ts/E8zCSEsG17dUqv7joXJFybuMLjQfWE04tsBODTxk=
 github.com/josharian/native v1.0.0/go.mod h1:7X/raswPFr05uY3HiLlYeyQntB6OO7E/d2Cu7qoaN2w=
 github.com/jsimonetti/rtnetlink v0.0.0-20190606172950-9527aa82566a/go.mod h1:Oz+70psSo5OFh8DBl0Zv2ACw7Esh6pPUphlvZG9x7uw=
@@ -164,8 +164,8 @@ golang.org/x/sys v0.0.0-20201101102859-da207088b7d1/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20210525143221-35b2ab0089ea/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20210927094055-39ccf1dd6fa6/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220209214540-3681064d5158/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20220502124256-b6088ccd6cba h1:AyHWHCBVlIYI5rgEM3o+1PLd0sLPcIAoaUckGQMaWtw=
+golang.org/x/sys v0.0.0-20220503163025-988cb79eb6c6 h1:nonptSpoQ4vQjyraW20DXPAglgQfVnM9ZC6MmNLMR60=
-golang.org/x/sys v0.0.0-20220502124256-b6088ccd6cba/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220503163025-988cb79eb6c6/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211 h1:JGgROgKl9N8DuW20oFS5gxc+lE67/N3FcwmBPMe7ArY=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=

proxy/ssh/ssh.go

@@ -1,6 +1,7 @@
 package ssh
 
 import (
+	"errors"
 	"net"
 	"net/url"
 	"os"
@@ -20,7 +21,8 @@ type SSH struct {
 	proxy  proxy.Proxy
 	addr   string
 
-	mu     sync.Mutex
+	mu     sync.RWMutex
+	once   sync.Once
 	conn   net.Conn
 	client *ssh.Client
 	config *ssh.ClientConfig
@@ -103,20 +105,14 @@ func (s *SSH) Addr() string {
 
 // Dial connects to the address addr on the network net via the proxy.
 func (s *SSH) Dial(network, addr string) (net.Conn, error) {
-	s.mu.Lock()
+	s.once.Do(func() { go s.keepConn() })
-	defer s.mu.Unlock()
 
-	if s.client != nil {
+	s.mu.RLock()
-		if c, err := s.dial(network, addr); err == nil {
+	defer s.mu.RUnlock()
-			return c, nil
+
-		}
+	if s.client == nil {
-		s.conn.Close()
+		return nil, errors.New("ssh client is nil")
 	}
-
-	if err := s.initConn(); err != nil {
-		return nil, err
-	}
-
 	return s.dial(network, addr)
 }
 
@@ -127,27 +123,48 @@ func (s *SSH) dial(network, addr string) (net.Conn, error) {
 	return c, err
 }
 
-func (s *SSH) initConn() error {
+func (s *SSH) connect() error {
+	s.mu.Lock()
+	defer s.mu.Unlock()
+
+	log.F("[ssh] trying connecting to %s", s.addr)
 	c, err := s.dialer.Dial("tcp", s.addr)
 	if err != nil {
-		log.F("[ssh]: dial to %s error: %s", s.addr, err)
+		log.F("[ssh] dial connection to %s error: %s", s.addr, err)
 		return err
 	}
 
 	c.SetDeadline(time.Now().Add(s.config.Timeout))
-	sshConn, sshChan, sshReq, err := ssh.NewClientConn(c, s.addr, s.config)
+	conn, ch, req, err := ssh.NewClientConn(c, s.addr, s.config)
 	if err != nil {
-		log.F("[ssh]: initial connection to %s error: %s", s.addr, err)
+		log.F("[ssh] initial connection to %s error: %s", s.addr, err)
 		c.Close()
 		return err
 	}
 	c.SetDeadline(time.Time{})
 
 	s.conn = c
-	s.client = ssh.NewClient(sshConn, sshChan, sshReq)
+	s.client = ssh.NewClient(conn, ch, req)
 	return nil
 }
 
+func (s *SSH) keepConn() {
+	sleep := time.Second
+	for {
+		if err := s.connect(); err != nil {
+			sleep *= 2
+			if sleep > time.Second*60 {
+				sleep = time.Second * 60
+			}
+			time.Sleep(sleep)
+			continue
+		}
+		sleep = time.Second
+		s.client.Conn.Wait()
+		s.conn.Close()
+	}
+}
+
 // DialUDP connects to the given address via the proxy.
 func (s *SSH) DialUDP(network, addr string) (pc net.PacketConn, err error) {
 	return nil, proxy.ErrNotSupported