3 files changed, 145 insertions(+), 1 deletions(-)

M README.md
A nanobnc.py
M ntalk.tcl

@@ 26,6 26,11 @@ the connection is done entirely over $sok, so set that to whatever.
 if you want to include e.g. tcltls, go ahead. the config file is saved
 to/read from ~/.config/ntalk/cscript.tcl.
 
+there is a `connect` proc available to the config, that automatically sets up the socket
+with the right encoding and line endings. it is called the same as `socket`. it is
+provided to make interacting with nanobnc.py easier. its use is not mandatory, ntalk will
+ensure the socket is setup right later.
+
 right click on any sixel in the chatlog, and you can save it under a custom name.
 saved sixels can be accessed through the "sixels" option in the top menu.
 slashes are interpreted, so naming one e.g. "faces / :D" will create a submenu called "faces".


@@ 61,6 66,35 @@ consists of the following scripts:
 - `9talk/motd addr`: checks for the most recent MOTD of $addr, and echos it. the most recent MOTD and last-seen message id are stored in $home/lib/9talk/$addr.motd and $home/lib/9talk/$addr.id, respectively.
 
 
+## `nanobnc.py`: simple nanochat bouncer
+
+this script should be run behind a connection broker, like socat. it assumes a client is
+attached to stdio. run it like:
+
+```
+socat TCP-LISTEN:22344,fork EXEC:'python nanobnc.py <password> [timeout]'
+```
+
+timeout is in seconds. it defaults to 1800, 30 minutes.
+
+when a client connects, it should send a line of the form `<addr> <port> <password>`. if
+the password matches the one passed as an argument, the script will connect to the
+upstream nanochat server at addr:port. data is blindly copied between the client and the
+upstream, until either the client and server are idle for timeout seconds, or until the
+client sends QUIT, at which point the script gracefully disconnects from the upstream
+server, and exits
+
+to use this with ntalk, replace the `set sok ...` line in your config with the following:
+
+```
+set sok [connect <bnc addr> <bnc port>]
+puts $sok "<upstream addr> <upstream port> <password>"
+```
+
+as this script is essentially an open TCP proxy, be very careful with your choice of
+password, and with who you allow to access the server. 
+
+
 ## `scrollbackup.sh`: simple backup script
 
 just sends HIST and QUIT and logs it to a file whose name indicates

@@ 0,0 1,104 @@
+#!/usr/bin/env python
+
+import socket
+import threading
+from sys import exit, argv, stderr, stdout, stdin
+from signal import alarm, signal, SIGALRM
+
+argv0 = 'nanobnc.py'
+sok = None
+
+def usage():
+	print(f'usage: {argv0} passphrase [timeout]')
+	exit(1)
+
+def handle_args():
+	global argv0, argv
+	if len(argv) > 0:
+		argv0 = argv[0]
+		argv = argv[1:]
+	if len(argv) not in (1, 2):
+		usage()
+
+	passphrase = argv[0]
+	if len(argv) == 1:
+		timeout = 1800
+	else:
+		timeout = int(argv[1])
+
+	return passphrase, timeout
+
+def handle_req(passphrase):
+	req = input().split(maxsplit=2)
+	if len(req) != 3:
+		print('bad # of connection args')
+		exit(3)
+	host, port, pw = req
+
+	if pw != passphrase:
+		print('bad passphrase')
+		print(f'bad passphrase trying to connect to {host}:{port}', file=stderr)
+		exit(4)
+
+	try:
+		port = int(port)
+	except:
+		print('bad port')
+		exit(3)
+
+	return host, port
+
+def shutdown():
+	if sok is not None:
+		try:
+			sok.sendall(b'QUIT\n')
+			sok.shutdown(socket.SHUT_RDWR)
+		except:
+			pass
+
+def onalarm(sig, stk):
+	try:
+		print('timeout!')
+		stdout.flush()
+	except:
+		pass
+	try:
+		print('timeout!', file=stderr)
+		stderr.flush()
+	except:
+		pass
+
+	shutdown()
+	exit(2)
+
+signal(SIGALRM, onalarm)
+
+passphrase, timeout = handle_args()
+alarm(timeout)
+host, port = handle_req(passphrase)
+
+try:
+	sok = socket.create_connection((host, port))
+except Exception as e:
+	print(f'connection failed: {e}')
+	exit(5)
+
+def toserver():
+	while (s := stdin.readline()) != '':
+		if s == 'QUIT\n':
+			break
+		sok.sendall(s.encode())
+	shutdown()
+	exit(0)
+
+def toclient():
+	fp = sok.makefile('r', encoding='ascii', errors='ignore')
+	while (s := fp.readline()) != '':
+		stdout.write(s)
+		stdout.flush()
+	shutdown()
+	exit(0)
+
+t = threading.Thread(target=toclient)
+t.start()
+toserver()

@@ 502,6 502,12 @@ bind .buffer <Button-3> {
 
 ### SERVER MANAGEMENT ###
 
+proc connect {addr port} {
+	set sok [socket $addr $port]
+	fconfigure $sok -translation lf -blocking false -encoding iso8859-1
+	return $sok
+}
+
 proc gencscript {{server localhost} {port 44322}} {
 	set server [list $server]
 	set port [list $port]


@@ 516,7 522,7 @@ proc gencscript {{server localhost} {port 44322}} {
 set server $server
 set port $port
 }]
-	append ret {set sok [socket $server $port]}
+	append ret {set sok [connect $server $port]}
 	return [string trim $ret]
 }