func ExampleNewServerConn() {
// An SSH server is represented by a ServerConfig, which holds
// certificate details and handles authentication of ServerConns.
config := &ssh.ServerConfig{
PasswordCallback: func(c ssh.ConnMetadata, pass []byte) (*ssh.Permissions, error) {
// Should use constant-time compare (or better, salt+hash) in
// a production setting.
if c.User() == "testuser" && string(pass) == "tiger" {
return nil, nil
}
return nil, fmt.Errorf("password rejected for %q", c.User())
},
}
privateBytes, err := ioutil.ReadFile("id_rsa")
if err != nil {
panic("Failed to load private key")
}
private, err := ssh.ParsePrivateKey(privateBytes)
if err != nil {
panic("Failed to parse private key")
}
config.AddHostKey(private)
// Once a ServerConfig has been configured, connections can be
// accepted.
listener, err := net.Listen("tcp", "0.0.0.0:2022")
if err != nil {
panic("failed to listen for connection")
}
nConn, err := listener.Accept()
if err != nil {
panic("failed to accept incoming connection")
}
// Before use, a handshake must be performed on the incoming
// net.Conn.
_, chans, reqs, err := ssh.NewServerConn(nConn, config)
if err != nil {
panic("failed to handshake")
}
// The incoming Request channel must be serviced.
go ssh.DiscardRequests(reqs)
// Service the incoming Channel channel.
for newChannel := range chans {
// Channels have a type, depending on the application level
// protocol intended. In the case of a shell, the type is
// "session" and ServerShell may be used to present a simple
// terminal interface.
if newChannel.ChannelType() != "session" {
newChannel.Reject(ssh.UnknownChannelType, "unknown channel type")
continue
}
channel, requests, err := newChannel.Accept()
if err != nil {
panic("could not accept channel.")
}
// Sessions have out-of-band requests such as "shell",
// "pty-req" and "env". Here we handle only the
// "shell" request.
go func(in <-chan *ssh.Request) {
for req := range in {
ok := false
switch req.Type {
case "shell":
ok = true
if len(req.Payload) > 0 {
// We don't accept any
// commands, only the
// default shell.
ok = false
}
}
req.Reply(ok, nil)
}
}(requests)
term := terminal.NewTerminal(channel, "> ")
go func() {
defer channel.Close()
for {
line, err := term.ReadLine()
if err != nil {
break
}
fmt.Println(line)
}
}()
}
}
func newServerShell(ch Channel, in <-chan *Request, prompt string) *terminal.Terminal {
term := terminal.NewTerminal(ch, prompt)
go handleTerminalRequests(in)
return term
}
func (app *h2i) Main() error {
cfg := &tls.Config{
ServerName: app.host,
NextProtos: strings.Split(*flagNextProto, ","),
InsecureSkipVerify: *flagInsecure,
}
hostAndPort := withPort(app.host)
log.Printf("Connecting to %s ...", hostAndPort)
tc, err := tls.Dial("tcp", hostAndPort, cfg)
if err != nil {
return fmt.Errorf("Error dialing %s: %v", withPort(app.host), err)
}
log.Printf("Connected to %v", tc.RemoteAddr())
defer tc.Close()
if err := tc.Handshake(); err != nil {
return fmt.Errorf("TLS handshake: %v", err)
}
if !*flagInsecure {
if err := tc.VerifyHostname(app.host); err != nil {
return fmt.Errorf("VerifyHostname: %v", err)
}
}
state := tc.ConnectionState()
log.Printf("Negotiated protocol %q", state.NegotiatedProtocol)
if !state.NegotiatedProtocolIsMutual || state.NegotiatedProtocol == "" {
return fmt.Errorf("Could not negotiate protocol mutually")
}
if _, err := io.WriteString(tc, http2.ClientPreface); err != nil {
return err
}
app.framer = http2.NewFramer(tc, tc)
oldState, err := terminal.MakeRaw(0)
if err != nil {
return err
}
defer terminal.Restore(0, oldState)
var screen = struct {
io.Reader
io.Writer
}{os.Stdin, os.Stdout}
app.term = terminal.NewTerminal(screen, "h2i> ")
lastWord := regexp.MustCompile(`.+\W(\w+)$`)
app.term.AutoCompleteCallback = func(line string, pos int, key rune) (newLine string, newPos int, ok bool) {
if key != '\t' {
return
}
if pos != len(line) {
// TODO: we're being lazy for now, only supporting tab completion at the end.
return
}
// Auto-complete for the command itself.
if !strings.Contains(line, " ") {
var name string
name, _, ok = lookupCommand(line)
if !ok {
return
}
return name, len(name), true
}
_, c, ok := lookupCommand(line[:strings.IndexByte(line, ' ')])
if !ok || c.complete == nil {
return
}
if strings.HasSuffix(line, " ") {
app.logf("%s", strings.Join(c.complete(), " "))
return line, pos, true
}
m := lastWord.FindStringSubmatch(line)
if m == nil {
return line, len(line), true
}
soFar := m[1]
var match []string
for _, cand := range c.complete() {
if len(soFar) > len(cand) || !strings.EqualFold(cand[:len(soFar)], soFar) {
continue
}
match = append(match, cand)
}
if len(match) == 0 {
return
}
if len(match) > 1 {
// TODO: auto-complete any common prefix
app.logf("%s", strings.Join(match, " "))
return line, pos, true
}
newLine = line[:len(line)-len(soFar)] + match[0]
return newLine, len(newLine), true
}
errc := make(chan error, 2)
go func() { errc <- app.readFrames() }()
go func() { errc <- app.readConsole() }()
return <-errc
}