#!/usr/bin/ruby

# dumb telnet client
# Author: Yoann Guillot 2009
# License: WtfPLv2

require 'socket'

class Telnet
	attr_accessor :s

	def initialize(host, port=23)
		@s = TCPSocket.open(host, port)
	end

	# reads from the socket until nothing is available for timeout seconds
	# interprets & reject telnet negotiation messages
	def read(timeout=0.4)
		buf = ''
		while IO.select([@s], nil, nil, timeout) and buf.length < 512
			case c = @s.read(1)[0]
			when 255	# telnet msg
				case c = @s.read(1)[0]
				when 253, 251	# want/will use option
					c = @s.read(1)[0]
					puts "telnetneg: refusing #{c}" if $DEBUG
					@s.write [255, 252, c].pack('C*')
				else
					puts "telnetneg: unk msg #{c}" if $VERBOSE
				end
			when 0x80..0xff
				puts "telnetneg: unk #{c}" if $VERBOSE
			else
				buf << c
			end
		end
		buf
	end

	def write(s) @s.write s end

	def puts(*s) s.each { |s_| write s_.chomp + "\r\n" } end

	# calls puts() and read()
	def cmd(*s) puts(*s) ; read end
end

if __FILE__ == $0
require 'optparse'

# default options
opts = { :host => '192.168.1.1', :port => 23, :login => 'root', :pass => 'root', :cmd => [] }

# 1st arg: [login[:pass]@]host[:port]
if ARGV.first =~ /^(?:(.*?)(?::(.*?))?@)?([a-zA-Z0-9].*?)(?::(.*?))?$/
	opts[:login] = $1 if $1
	opts[:pass] = $2 if $2
	opts[:host] = $3
	opts[:port] = $4 if $4
end

# parse options
OptionParser.new { |opt|
	opt.on('-h h', '--host h') { |h| opts[:host] = h }
	opt.on('-p p', '--port p') { |p| opts[:port] = p }
	opt.on('-l l', '--login l') { |l| opts[:login] = l }
	opt.on('-P p', '--pass p') { |p| opts[:pass] = p }
	opt.on('-c cmd', '--cmd c') { |c| opts[:cmd] << c }
}.parse!(ARGV)

p opts if $DEBUG

$stdout.sync = true

# connect
t = Telnet.new(opts[:host], opts[:port])
# login
cx = t.cmd(opts[:login]) + t.cmd(opts[:pass])
print cx if $VERBOSE
# send cmdline commands
opts[:cmd].each { |c| print t.cmd(c) }
# keyboard interact
loop do
	next if not IO.select([$stdin, t.s], nil, nil, 4)
	print t.read(0)
	if IO.select([$stdin], nil, nil, 0)
		c = $stdin.gets
		print t.cmd(c)
	end
end
end