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SSH tunnelling in Golang
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package main | |
import ( | |
"log" | |
"bufio" | |
"time" | |
"os" | |
"fmt" | |
"io" | |
"net" | |
"golang.org/x/crypto/ssh" | |
"golang.org/x/crypto/ssh/agent" | |
) | |
type Endpoint struct { | |
Host string | |
Port int | |
} | |
func (endpoint *Endpoint) String() string { | |
return fmt.Sprintf("%s:%d", endpoint.Host, endpoint.Port) | |
} | |
type SSHtunnel struct { | |
Local *Endpoint | |
Server *Endpoint | |
Remote *Endpoint | |
Config *ssh.ClientConfig | |
} | |
func (tunnel *SSHtunnel) Start() error { | |
listener, err := net.Listen("tcp", tunnel.Local.String()) | |
if err != nil { | |
return err | |
} | |
defer listener.Close() | |
for { | |
conn, err := listener.Accept() | |
if err != nil { | |
return err | |
} | |
go tunnel.forward(conn) | |
} | |
} | |
func (tunnel *SSHtunnel) forward(localConn net.Conn) { | |
serverConn, err := ssh.Dial("tcp", tunnel.Server.String(), tunnel.Config) | |
if err != nil { | |
fmt.Printf("Server dial error: %s\n", err) | |
return | |
} | |
remoteConn, err := serverConn.Dial("tcp", tunnel.Remote.String()) | |
if err != nil { | |
fmt.Printf("Remote dial error: %s\n", err) | |
return | |
} | |
copyConn:=func(writer, reader net.Conn) { | |
defer writer.Close() | |
defer reader.Close() | |
_, err:= io.Copy(writer, reader) | |
if err != nil { | |
fmt.Printf("io.Copy error: %s", err) | |
} | |
} | |
go copyConn(localConn, remoteConn) | |
go copyConn(remoteConn, localConn) | |
} | |
func SSHAgent() ssh.AuthMethod { | |
if sshAgent, err := net.Dial("unix", os.Getenv("SSH_AUTH_SOCK")); err == nil { | |
return ssh.PublicKeysCallback(agent.NewClient(sshAgent).Signers) | |
} | |
return nil | |
} | |
func main() { | |
localEndpoint := &Endpoint{ | |
Host: "localhost", | |
Port: 9000, | |
} | |
serverEndpoint := &Endpoint{ | |
Host: "example.com", | |
Port: 22, | |
} | |
remoteEndpoint := &Endpoint{ | |
Host: "localhost", | |
Port: 8080, | |
} | |
sshConfig := &ssh.ClientConfig{ | |
User: "vcap", | |
Auth: []ssh.AuthMethod{ | |
SSHAgent(), | |
}, | |
} | |
tunnel := &SSHtunnel{ | |
Config: sshConfig, | |
Local: localEndpoint, | |
Server: serverEndpoint, | |
Remote: remoteEndpoint, | |
} | |
tunnel.Start() | |
} |
I updated the copyConn
to close the connections when the function finishes its job. Thanks for the feedback.
Svett, thanks for the sample code. Under which license, if any, is this released?
MIT
work for me
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yeah, this was a huge bug for me, now is fixed here elliotchance/sshtunnel#1