Add web proxy for control interface

Add web application exposing Control Interface over web. All of SET, GET
and TRAP are fully supported.

Notice: TRAP is converted into 'Server-sent events' according to RFC
6202, see also https://www.w3.org/TR/eventsource/ - this requires
corresponding client.

Due to use of special prefix modified version of python
eventsource-client is necessary ATM.

Change-Id: I87d40c80061f8b3d02d656ab8cadabbfb871b461
Related: OS#1646

1 files changed, 147 insertions, 0 deletions

diff --git a/openbsc/contrib/ctrl2sse.py b/openbsc/contrib/ctrl2sse.py
new file mode 100755
index 000000000..8b630ecfd
--- /dev/null
+++ b/openbsc/contrib/ctrl2sse.py
@@ -0,0 +1,147 @@
+#!/usr/bin/python2
+
+mod_license = '''
+/*
+ * Copyright (C) 2016 sysmocom s.f.m.c. GmbH
+ *
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+'''
+
+import sys, argparse, random, logging, tornado.ioloop, tornado.web, tornado.tcpclient, tornado.httpclient, eventsource, bsc_control
+from eventsource import listener, request
+
+'''
+N. B: this is not an example of building proper REST API or building secure web application.
+It's only purpose is to illustrate conversion of Osmocom's Control Interface to web-friendly API.
+Exposing this to Internet while connected to production network might lead to all sorts of mischief and mayhem
+from NSA' TAO breaking into your network to zombie apocalypse. Do NOT do that.
+'''
+
+token = None
+stream = None
+url = None
+
+'''
+Returns json according to following schema - see http://json-schema.org/documentation.html for details:
+{
+        "title": "Ctrl Schema",
+        "type": "object",
+        "properties": {
+                "variable": {
+                        "type": "string"
+                },
+                "varlue": {
+                        "type": "string"
+                }
+        },
+        "required": ["interface", "variable", "value"]
+}
+Example validation from command-line:
+json validate --schema-file=schema.json --document-file=data.json
+The interface is represented as string because it might look different for IPv4 vs v6.
+'''
+
+def read_header(data):
+	t_length = bsc_control.ipa_ctrl_header(data)
+	if (t_length):
+		stream.read_bytes(t_length - 1, callback = read_trap)
+	else:
+		print >> sys.stderr, "protocol error: length missing in %s!" % data
+
+@tornado.gen.coroutine
+def read_trap(data):
+	(t, z, v, p) = data.split()
+	if (t != 'TRAP' or int(z) != 0):
+		print >> sys.stderr, "protocol error: TRAP != %s or 0! = %d" % (t, int(z))
+	else:
+		yield tornado.httpclient.AsyncHTTPClient().fetch(tornado.httpclient.HTTPRequest(url = "%s/%s/%s" % (url, "ping", token),
+												method = 'POST',
+												headers = {'Content-Type': 'application/json'},
+												body = tornado.escape.json_encode({ 'variable' : v, 'value' : p })))
+		stream.read_bytes(4, callback = read_header)
+
+@tornado.gen.coroutine
+def trap_setup(host, port, target_host, target_port, tk):
+	global stream
+	global url
+	global token
+	token = tk
+	url = "http://%s:%s/sse" % (host, port)
+	stream = yield tornado.tcpclient.TCPClient().connect(target_host, target_port)
+	stream.read_bytes(4, callback = read_header)
+
+def get_v(s, v):
+	return { 'variable' : v, 'value' : bsc_control.get_var(s, tornado.escape.native_str(v)) }
+
+class CtrlHandler(tornado.web.RequestHandler):
+	def initialize(self):
+		self.skt = bsc_control.connect(self.settings['ctrl_host'], self.settings['ctrl_port'])
+
+	def get(self, v):
+		self.write(get_v(self.skt, v))
+
+	def post(self):
+		self.write(get_v(self.skt, self.get_argument("variable")))
+
+class SetCtrl(CtrlHandler):
+	def get(self, var, val):
+		bsc_control.set_var(self.skt, tornado.escape.native_str(var), tornado.escape.native_str(val))
+		super(SetCtrl, self).get(tornado.escape.native_str(var))
+
+	def post(self):
+		bsc_control.set_var(self.skt, tornado.escape.native_str(self.get_argument("variable")), tornado.escape.native_str(self.get_argument("value")))
+		super(SetCtrl, self).post()
+
+class Slash(tornado.web.RequestHandler):
+	def get(self):
+		self.write('<html><head><title>%s</title></head><body>Using Tornado framework v%s'
+				'<form action="/get" method="POST">'
+					'<input type="text" name="variable">'
+					'<input type="submit" value="GET">'
+				'</form>'
+				'<form action="/set" method="POST">'
+					'<input type="text" name="variable">'
+					'<input type="text" name="value">'
+					'<input type="submit" value="SET">'
+				'</form>'
+				'</body></html>' % ("Osmocom Control Interface Proxy", tornado.version))
+
+if __name__ == '__main__':
+	p = argparse.ArgumentParser(description='Osmocom Control Interface proxy.')
+	p.add_argument('-c', '--control-port', type = int, default = 4252, help = "Target Control Interface port")
+	p.add_argument('-a', '--control-host', default = 'localhost', help = "Target Control Interface adress")
+	p.add_argument('-b', '--host', default = 'localhost', help = "Adress to bind proxy's web interface")
+	p.add_argument('-p', '--port', type = int, default = 6969, help = "Port to bind proxy's web interface")
+	p.add_argument('-d', '--debug', action='store_true', help = "Activate debugging (default off)")
+	p.add_argument('-t', '--token', default = 'osmocom', help = "Token to be used by SSE client in URL e. g. http://127.0.0.1:8888/poll/osmocom where 'osmocom' is default token value")
+	p.add_argument('-k', '--keepalive', type = int, default = 5000, help = "Timeout betwwen keepalive messages, in milliseconds, defaults to 5000")
+	args = p.parse_args()
+	random.seed()
+	tornado.netutil.Resolver.configure('tornado.netutil.ThreadedResolver') # Use non-blocking resolver
+	logging.basicConfig()
+	application = tornado.web.Application([
+		(r"/", Slash),
+		(r"/get", CtrlHandler),
+		(r"/get/(.*)", CtrlHandler),
+		(r"/set", SetCtrl),
+		(r"/set/(.*)/(.*)", SetCtrl),
+		(r"/sse/(.*)/(.*)", listener.EventSourceHandler, dict(event_class = listener.JSONIdEvent, keepalive = args.keepalive)),
+	], debug = args.debug, ctrl_host = args.control_host, ctrl_port = args.control_port)
+	application.listen(address = args.host, port = args.port)
+	trap_setup(args.host, args.port, application.settings['ctrl_host'], application.settings['ctrl_port'], args.token)
+	tornado.ioloop.IOLoop.instance().start()