From 1ee7b787ed4c4a2d5de49ffb1f689bc4a3e75bbe Mon Sep 17 00:00:00 2001
From: Philip Trauner <philip.trauner@aol.com>
Date: Sat, 8 Oct 2016 21:53:02 +0200
Subject: [PATCH] Initial network discovery prototype

---
 Shared/Disc0very.py | 96 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 96 insertions(+)
 create mode 100644 Shared/Disc0very.py

diff --git a/Shared/Disc0very.py b/Shared/Disc0very.py
new file mode 100644
index 0000000..769aff9
--- /dev/null
+++ b/Shared/Disc0very.py
@@ -0,0 +1,96 @@
+from socket import *
+from random import getrandbits
+from time import time
+from time import sleep
+import Utils
+import Logging
+from _thread import start_new_thread
+
+HEY = "HEY".encode()
+IDENT_SEED_LENGTH = 64
+WHAT = "WHAT".encode()
+
+
+class MissingInterfaceError(TypeError):
+	def __init__(self):
+		super(TypeError, self).__init__("platform requires interface parameter.")	
+
+
+class Disc0very:
+	def __init__(self, port, interface="eth0", max_peers=32):
+		self.port = port
+		self.ident = getrandbits(max_peers * 2)
+		self.sock = socket(AF_INET, SOCK_DGRAM)
+		self.sock.setsockopt(SOL_SOCKET, SO_REUSEADDR, 1)
+		self.sock.setsockopt(SOL_SOCKET, SO_BROADCAST, 1)
+		self.sock.bind(("", self.port))
+		self.discovering = False
+		self.enlisting = False
+		
+
+
+
+	def discover(self, time_out=2):
+		if not self.enlisting:
+			self.discovering = True
+			self.sock.setblocking(False)
+			self.sock.sendto(HEY, ('255.255.255.255', self.port))
+			end_time = time() + time_out
+			servers = []
+			while time() < end_time:
+				try:
+					data = self.sock.recv(512)
+					if data != HEY:
+						servers.append(data)
+				except BlockingIOError:
+					sleep(0.2)
+			self.discovering = False
+			if len(servers) == 0:
+				return None
+			elif len(servers) > 1:
+				self.sock.sendto(WHAT, ('255.255.255.255', self.port))
+			else:
+				return servers[0]
+		
+
+	def enlist(self, interface, blocking=False):
+		if not self.discovering:
+			if blocking:
+				self.__enlist(interface)
+			else:
+				start_new_thread(self.__enlist, (interface, ))
+
+
+	# Interface should always be provided when using a Wallaby
+	# because wlan0 and wlan1 have an IP address assigned
+	def __enlist(self, interface=None):
+		self.enlisting = True
+		self.sock.setblocking(True)
+		ip_address = Utils.get_ip_address(interface)
+		data = ""
+		while True:
+			try:
+				data = self.sock.recv(512)
+			except BlockingIOError:
+				sleep(0.1)
+			if data == HEY:
+				self.sock.sendto(ip_address.encode(), ('255.255.255.255', self.port))
+			elif data == WHAT:
+				Logging.error("Apparently more than one server is running. "
+					"Investigating...")
+			 	# Discover and if other server is found shutdown
+
+
+def start():
+	print("starting")
+
+
+if __name__ == "__main__":
+	from time import sleep
+	disc0very = Disc0very(3077)
+	server = disc0very.discover()
+	if not server:
+		print("enlisted")
+		disc0very.enlist(None, blocking=True)
+	else:
+		print(server)
\ No newline at end of file