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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() | |
| } |
Author
Author
Svett, thanks for the sample code. Under which license, if any, is this released?
MIT
work for me
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I updated the
copyConnto close the connections when the function finishes its job. Thanks for the feedback.