Crypto ssh how to read the stdout pipe end?

songtianyi · June 27, 2017, 10:44am

Oh my lord. The bytes read from StdoutPipe is not line by line!

[line]   inspect skinny
  inspect esmtp

[line]   inspect sqlnet

[line]   inspect sunrpc
  inspect tftp

[line]   inspect sip
  inspect xdmcp

[line] policy-map type inspect dns migrated_dns_map_2
 parameters

[line]   message-length maximum client auto
  message-length maximum 512
  no tcp-inspection
!
service-policy global_policy global
prompt hostname context
no call-home reporting anonymous
call-home
 profile CiscoTAC-1
  no active
  destination address http https://tools.cisco.com/its/service/oddce/services/DDCEService
  destination address email callhome@cisco.com
  destination transport-method http
  subscribe-to-alert-group diagnostic
  subscribe-to-alert-group environment
  subscribe-to-alert-group inventory periodic monthly
  subscribe-to-alert-group configuration periodic monthly
  subscribe-to-alert-group telemetry periodic daily
 profile License
  destination address http https://tools.cisco.com/its/service/oddce/services/DDCEService

[line]   destination transport-method http
Cryptochecksum:f615c78cc7913affb2f486489897b63e
: end

9dadcd0b-75f4-4a71-8a95-6f08c18d761c(config)#

Last line which end with prompt matched the prompt pattern, so this line was ignored by the code pasted above.

9dadcd0b-75f4-4a71-8a95-6f08c18d761c(config)#

nathankerr · June 27, 2017, 10:48am

If you need to read lines, use bufio.Scanner.

songtianyi · June 27, 2017, 10:49am

Ok, i will try.

songtianyi · June 28, 2017, 2:57am

How to disable echoing?

var (
    modes = cssh.TerminalModes{
        cssh.ECHO:          0,     // disable echoing
        cssh.TTY_OP_ISPEED: 14400, // input speed = 14.4kbaud
        cssh.TTY_OP_OSPEED: 14400, // output speed = 14.4kbaud
    }
)
if err := session.RequestPty("xterm", 0, 0, modes); err != nil {
    return nil, err
}

Set TerminalModes is helpless. The output read from StdoutPipe contains what we written to StdinPipe

dfc · June 28, 2017, 7:24am

Stop requesting a Pty, that is what is causing the remote end to think you are human and doing unhelpful things like pagination and echo.

dfc · June 28, 2017, 7:26am

With that said, we’ve already established that the cisco remote side is not really a shell so maybe it doesn’t behave like we hope.

You might have to filter out your input when it is returned to you.

I know there are lots of these types of programs wirtten in python and Perl, I’d recommend reading their source to understand how they worked around the unfriendly cisco console

ipcjk · July 5, 2017, 9:33am

I wrote and use this (mlxsh) almost all time in managing my Brocade routers. May also work for your Cisco if login is comparable. Take a look at the function readTill:

github.com

ipcjk/mlxsh/blob/master/netironDevice/netiron.go#L182




	switch b.Router.PromptMode {
	case "sshEnabled":
		if targetMode == "sshConfig" {
			b.ConfigureTerminalMode()
		} else {
			if err := b.Router.Write(b.RTC, "exit\n"); err != nil {
				return err
			}
		}
	case "sshConfig":
		if targetMode == "sshEnabled" {
			if err := b.Router.Write(b.RTC, "end\n"); err != nil {
				return err
			}
		} else {
			if err := b.Router.Write(b.RTC, "end\n"); err != nil {
				return err
			}
			if err := b.Router.Write(b.RTC, "exit\n"); err != nil {
				return err

Jörg

system · October 3, 2017, 9:38am

This topic was automatically closed 90 days after the last reply. New replies are no longer allowed.