| #! /usr/local/python |
| |
| # Minimal interface to the Internet telnet protocol. |
| # |
| # It refuses all telnet options and does not recognize any of the other |
| # telnet commands, but can still be used to connect in line-by-line mode. |
| # It's also useful to play with a number of other services, |
| # like time, finger, smtp and even ftp. |
| # |
| # Usage: telnet host [port] |
| # |
| # The port may be a service name or a decimal port number; |
| # it defaults to 'telnet'. |
| |
| |
| import sys, posix, time |
| from socket import * |
| |
| BUFSIZE = 1024 |
| |
| # Telnet protocol characters |
| |
| IAC = chr(255) # Interpret as command |
| DONT = chr(254) |
| DO = chr(253) |
| WONT = chr(252) |
| WILL = chr(251) |
| |
| def main(): |
| host = sys.argv[1] |
| try: |
| hostaddr = gethostbyname(host) |
| except error: |
| sys.stderr.write(sys.argv[1] + ': bad host name\n') |
| sys.exit(2) |
| # |
| if len(sys.argv) > 2: |
| servname = sys.argv[2] |
| else: |
| servname = 'telnet' |
| # |
| if '0' <= servname[:1] <= '9': |
| port = eval(servname) |
| else: |
| try: |
| port = getservbyname(servname, 'tcp') |
| except error: |
| sys.stderr.write(servname + ': bad tcp service name\n') |
| sys.exit(2) |
| # |
| s = socket(AF_INET, SOCK_STREAM) |
| # |
| try: |
| s.connect(host, port) |
| except error, msg: |
| sys.stderr.write('connect failed: ' + `msg` + '\n') |
| sys.exit(1) |
| # |
| pid = posix.fork() |
| # |
| if pid == 0: |
| # child -- read stdin, write socket |
| while 1: |
| line = sys.stdin.readline() |
| s.send(line) |
| else: |
| # parent -- read socket, write stdout |
| iac = 0 # Interpret next char as command |
| opt = '' # Interpret next char as option |
| while 1: |
| data = s.recv(BUFSIZE) |
| if not data: |
| # EOF; kill child and exit |
| sys.stderr.write( '(Closed by remote host)\n') |
| posix.kill(pid, 9) |
| sys.exit(1) |
| cleandata = '' |
| for c in data: |
| if opt: |
| print ord(c) |
| s.send(opt + c) |
| opt = '' |
| elif iac: |
| iac = 0 |
| if c == IAC: |
| cleandata = cleandata + c |
| elif c in (DO, DONT): |
| if c == DO: print '(DO)', |
| else: print '(DONT)', |
| opt = IAC + WONT |
| elif c in (WILL, WONT): |
| if c == WILL: print '(WILL)', |
| else: print '(WONT)', |
| opt = IAC + DONT |
| else: |
| print '(command)', ord(c) |
| elif c == IAC: |
| iac = 1 |
| print '(IAC)', |
| else: |
| cleandata = cleandata + c |
| sys.stdout.write(cleandata) |
| sys.stdout.flush() |
| |
| |
| try: |
| main() |
| except KeyboardInterrupt: |
| pass |