main.py

#!/usr/bin/python3
import os, re, signal, sys
import rest_service as service
import view
from exceptions import GoBack, InvalidNodeId
from lxml import etree
import libxml2
import ipaddress
from dijkstar import Graph, find_path


## Signal handler
def ctrl_c_handler(sig, frame):
    close()

## Controller data transformations M->V
## Purge and modify data from the model to provide it to the view.
def _clean_namespaces(xml):
	xml = re.sub(' xmlns="[^"]+"', '', xml)
	xml = re.sub(' xmlns:a="[^"]+"', '', xml)
	return xml

def _retrieve_topology(xml):
	xml = _clean_namespaces(xml)
	
	view_tree = etree.Element("nodes")
	context = libxml2.parseDoc(xml)
	# Store representation of nodes and links received from model
	m_nodes = context.xpathEval("/network-topology/topology/node")
	m_links = context.xpathEval("/network-topology/topology/link")

	_clean_graph()

	for n in m_nodes:
		node_id = str(libxml2.parseDoc(str(n)).xpathEval('/node/node-id/text()')[0])
		if node_id[0:4] == "host":
			node_ip = str(libxml2.parseDoc(str(n)).xpathEval('/node/addresses/ip/text()')[0])
			_add_node(node_id, node_ip)
		else:
			_add_node(node_id, "")

	for l in m_links:
		aux = str(libxml2.parseDoc(str(l)).xpathEval('/link/link-id/text()')[0])
		# A pair of port ids => for hosts matches with id, for switch it does not
		lsrc = str(libxml2.parseDoc(str(l)).xpathEval('/link/source/source-tp/text()')[0])
		ldst = str(libxml2.parseDoc(str(l)).xpathEval('/link/destination/dest-tp/text()')[0])
		src_ref, dst_ref = _get_node_pos(lsrc), _get_node_pos(ldst)
		_add_link(src_ref, dst_ref)

	_build_graph()

	if not flows_ready:
		_init_flows()
		_init_flows_ports()
		enable_all()

def _get_node_flows_view_xml(xml):
	xml = _clean_namespaces(xml)
	return xml


####

## Controller logic
## Perform actions on controller variables
def _clean_graph():
	graph = Graph()
	nodes = []
	links = []

def _add_node(node_id, node_ip):
	nodes.append((node_id, node_ip))

def _get_node_pos(node_ref):
	# Get index i of next element i,v in nodes wich value v matches node_ref
	try:
		return nodes.index(next(i for i in nodes if node_ref.find(i[0]) != -1 or node_ref == i[1] ))
	except:
		pass

def _add_link(node1_ref, node2_ref):
	links.append((node1_ref, node2_ref))

def _build_graph():
	for l in links:
		graph.add_edge(l[0],l[1],1)

def _get_path(ref1, ref2):
	id1 = _get_node_pos(ref1)
	id2 = _get_node_pos(ref2)
	return find_path(graph, id1, id2)

####


## MVC communications
## Call service functions, model-view transformations and controller logic functions
def _is_ip(string):
	try:
		ipaddress.IPv4Address(string)
		print("IPv4 detected")
		True
	except ipaddress.AddressValueError:
		print("Node id detected")
		False

def _is_switch(identifier):
	return not identifier[:4] == "host"

def _is_error(func, *args, **kw):
    try:
        func(*args, **kw)
        return False
    except Exception:
        return True

def _remove_duplicateds(links):
	nodups= []
	for i in range(len(links)-1):
		if not (links[i][1],links[i][0]) in nodups:
			nodups.append((links[i][0],links[i][1]))
	return nodups


def _get_flows_ids(xml):
	xml = _clean_namespaces(xml)

	context = libxml2.parseDoc(xml)
	# Store representation of nodes and links received from model
	ids = [str(i) for i in libxml2.parseDoc(str(xml)).xpathEval('/table/flow/id/text()')]
	return ids

def _get_first_ports_refs(xml):
	xml = _clean_namespaces(xml)

	context = libxml2.parseDoc(xml)
	# Store representation of ports received from model
	ids = [str(i).split(":")[-1] for i in libxml2.parseDoc(str(xml)).xpathEval('/node/node-connector/id/text()')]
	clean_ids = [i for i in ids if not _is_error(int,i)]
	return clean_ids

def _get_ports_refs(node_ref):
	if node_ref in flows:
		return  [k for k,v in flows[node_ref].items()]
	else:
		raise InvalidNodeId


def _get_flow_id_for_port(xml, port_ref):
	xml = _clean_namespaces(xml)
	context = libxml2.parseDoc(xml)
	# Store representation of nodes and links received from model
	flows = context.xpathEval("/table/flow")
	for f in flows:
		if str(libxml2.parseDoc(str(f)).xpathEval('/flow/flow-name/text()')[0]) == ("block_port_"+ port_ref):
			return str(libxml2.parseDoc(str(f)).xpathEval('/flow/id/text()')[0])
	return -1

def _get_port_with(node_ref, neighbor_ref, xml):
	context = libxml2.parseDoc(xml)
	links = context.xpathEval("/network-topology/topology/link")

	for l in links:
		if str(libxml2.parseDoc(str(l)).xpathEval('/link/source/source-node/text()')[0]) == node_ref and str(libxml2.parseDoc(str(l)).xpathEval('/link/destination/dest-node/text()')[0]) == neighbor_ref:
			return str(libxml2.parseDoc(str(l)).xpathEval('/link/source/source-tp/text()')[0])

def _set_node_port_mode(node_ref, port_ref, mode="enabled"):
	node_flows = flows[node_ref]
	if port_ref in node_flows:
		node_flows[port_ref] = mode
		if mode == "enabled":
			service.enable_port(node_ref, port_ref)
			print("Enabled " + node_ref + ":" + port_ref )
		else:
			service.disable_port(node_ref, port_ref)
			print("Disabled " + node_ref + ":" + port_ref )
	else:
		print("Invalid port.")

def _init_flows():
	for n in nodes:
		if _is_switch(n[0]):
			flows[n[0]] = {}
	flows_ready = True

def _init_flows_ports():
	for n in nodes:
		if _is_switch(n[0]):
			response = service.get_all_for(n[0])
			if response[0] == "ok":
				ports = _get_first_ports_refs(response[1])
				for p in ports:
					flows[n[0]][p] = "enabled"


def _show_flows_for_node(node_ref):
	print("Flows for node " + node_ref)
	if (node_ref,'') in nodes:
		for port,state in flows[node_ref].items():
			print(port + " : " + state)
	else:
		print("No valid node with that id.")


def show_topo():
	response = service.get_topo()
	_retrieve_topology(response[1])
	view.clean()
	view.show_hosts(nodes)
	view.show_links(_remove_duplicateds(links), nodes)

def show_node_flows():
	print("(Node id) ", end= '')
	node_id = input("> ")
	_show_flows_for_node(node_id)

def enable_all():
	view.clean()
	if nodes==[]:
		print("No nodes detected. Have you 'shown network topology' ?")
		back()
	else:
		for n in (n for n in nodes if _is_switch(n[0])):
			node_ref = n[0]	
			for key,val in flows[node_ref].items():
				if val == "disabled":
					_set_node_port_mode(node_ref, key, "enabled")
		print("All flows enabled")

def block_all():
	view.clean()
	if nodes==[]:
		print("No nodes detected. Have you 'shown network topology' ?")
		back()
	else:
		for n in (n for n in nodes if _is_switch(n[0])):
			node_ref = n[0]
			for key,val in flows[node_ref].items():
				if val == "enabled":
					_set_node_port_mode(node_ref, key, "disabled")
		print("All flows disabled")

def enable_port(node_ref=None, port_ref=None):
	if nodes==[]:
		print("No nodes detected. Have you 'shown network topology' ?")
		back()
	else:
		if node_ref == None:
			view.clean()
			print("(Node (switch) id) ", end='')
			node_ref = input("> ")
			try:
				ports = _get_ports_refs(node_ref)
				print("(Port id) " + str(ports) , end='')
				port_ref = input(" > ")
			except InvalidNodeId:
				print("Invalid node id.")
		if node_ref in flows:
			if flows[node_ref][port_ref] == "disabled":
				_set_node_port_mode(node_ref, port_ref, "enabled")
			else:
				print("Port already enabled.")
		else:
			print("This is not a topology switch")
			
		



def block_port(node_ref=None, port_ref=None):

	if nodes==[]:
		print("No nodes detected. Have you 'shown network topology' ?")
		back()
	else:
		if node_ref == None:
			view.clean()
			print("(Node (switch) id) ", end='')
			node_ref = input("> ")
			try:
				ports = _get_ports_refs(node_ref)
				print("(Port id) " + str(ports) , end='')
				port_ref = input(" > ")
				if node_ref in flows:
					if flows[node_ref][port_ref] == "enabled":
						_set_node_port_mode(node_ref, port_ref, "disabled")
					else:
						print("Port already disabled.")
				else:
					print("This is not a topology switch")
			except InvalidNodeId:
				print("Invalid node id.")

def enable_path():
	view.clean()
	if nodes==[]:
		print("No nodes detected. Have you 'shown network topology' ?")
		back()
	else:
		print("(Node 1 id | ip ) ", end='')
		node1_ref = input("> ")
		print("(Node 2 id | ip ) ", end='')
		node2_ref = input("> ")

		path = _get_path(node1_ref, node2_ref)
		response = service.get_topo()
		if response[0] == "ok":
			xml = _clean_namespaces(response[1])
			# Iterate over path.nodes (list of positions on nodes)
			for i in range(len(path.nodes)-1):
				# path.nodes[i] is the position in nodes of the i-th node of the path
				if _is_switch(nodes[path.nodes[i]][0]):
					port = _get_port_with(nodes[path.nodes[i]][0], nodes[path.nodes[i-1]][0], xml)
					enable_port(nodes[path.nodes[i]][0], port.split(":")[-1])
					port = _get_port_with(nodes[path.nodes[i]][0], nodes[path.nodes[i+1]][0], xml)
					enable_port(nodes[path.nodes[i]][0], port.split(":")[-1])

		else:
			print("Error! Could not retrieve needed topology.")
####
def back():
	view.clean()
	raise GoBack()

def close():
	view.clean()
	print("\nClosing application ...")
	sys.exit(0)

# Enable nodes menu
def enable_block_menu():
	print("\nEnable/Block nodes menu.")
	print("[0] Go back.")
	print("[1] Enable all flows.")
	print("[2] Block all flows.")
	print("[3] Enable a switch port.")
	print("[4] Block a switch port.")
	print("[5] Enable switch ports in a path.")
	return(input("> "))
	

# Enable nodes loop
def enable_block_loop():
	actions = {
		0: back,
		1: enable_all,
		2: block_all,
		3: enable_port,
		4: block_port,
		5: enable_path
	}
	while True:
		try:
			val = enable_block_menu()
			os.system("clear")
			actions[int(val)]()
		except KeyError as e:
			os.system("clear")
			print("Error! Invalid option \"", val, "\"")
		except GoBack:
			break
# Application menu
def main_menu():
	print("\nMain menu.")
	print("[0] Close application.")
	print("[1] Show network topology.")
	print("[2] Show flows for node.")
	print("[3] Block/Enable nodes ...")
	return input("> ")

# Application loop
def main_loop():
	# Map used to implement switch case
	actions = {
		0: close,
		1: show_topo,
		2: show_node_flows,
		3: enable_block_loop,
	}
	while True:
		try:
			val = main_menu()
			view.clean()
			actions[int(val)]()
		except KeyError as e:
			view.clean()
			print("Error! Invalid option \"", val, "\"")


try:
	# Initialization
	signal.signal(signal.SIGINT, ctrl_c_handler) # Register handler

	graph = Graph()
	nodes = []
	links = []
	flows = {}
	flows_ready = False

	# Display Wellcome
	os.system("clear")

	print("Wellcome to odl-multicast!")

	main_loop()

	close()
# Unhandled exceptions terminate application
except Exception as e:
	print(e)
	print("\nError!", e.__class__.__name__, "Exception occurred.")
	print("Terminating ...")
	sys.exit(1)