def generate_TTF(all_links):
''' Takes a list of sts.debugger_entities.Link objects (directed) '''
ttf = tf.TF(of.HS_FORMAT())
for link in all_links:
uniq_from_port = of.get_uniq_port_id(link.start_switch_impl, link.start_port)
uniq_to_port = of.get_uniq_port_id(link.end_switch_impl, link.end_port)
rule = tf.TF.create_standard_rule([uniq_from_port], None,[uniq_to_port], None, None)
ttf.add_link_rule(rule)
print "TTF: %s" % str(ttf)
return ttf
def compute_omega(NTF, TTF, edge_links, reverse_map={}, test_packet=None):
omega = {}
# TODO: need to model host end of link, or does switch end suffice?
edge_ports = map(lambda access_link: get_uniq_port_id(access_link.switch, access_link.switch_port), edge_links)
print "edge_ports: %s" % ports_to_hex(edge_ports)
for start_port in edge_ports:
port_omega = compute_single_omega(NTF, TTF, start_port, edge_ports, reverse_map, test_packet)
omega = dict(omega.items() + port_omega.items())
return omega
def compute_single_omega(NTF, TTF, start_port, edge_ports, reverse_map={}, test_packet=None):
if type(start_port) != int:
start_port = get_uniq_port_id(start_port.switch, start_port.switch_port)
if type(edge_ports) != list:
edge_ports = list(edge_ports)
if type(edge_ports[0]) != int:
edge_ports = map(lambda access_link: get_uniq_port_id(access_link.switch, access_link.switch_port), edge_ports)
print "port %s is being checked" % hex(start_port)
propagation = []
port_omega = {}
# put all-x test packet in propagation graph
test_pkt = test_packet
if test_pkt == None:
test_pkt = get_all_x(NTF)
p_node = {}
p_node["hdr"] = test_pkt
p_node["port"] = start_port
p_node["visits"] = []
p_node["hs_history"] = []
propagation.append(p_node)
while len(propagation) > 0:
# get the next node in propagation graph and apply it to NTF and TTF
print " -- Propagation has length: %d --" % len(propagation)
tmp_propag = []
for p_node in propagation:
print "Checking port: %s hdr: %s" % (port_to_hex(p_node["port"]), str(p_node["hdr"]))
# hp is "header port"
next_hps = NTF.T(p_node["hdr"],p_node["port"])
for (next_h,next_ps) in next_hps:
for next_p in next_ps:
sys.stdout.write(" next_hp: %s -> %s" % (port_to_hex(next_p),str(next_h)))
# Note: right now, we encode packet drops as a lack of a leave in the propogation graph
# TODO: not in (not edge ports) would work better
if next_p in edge_ports:
# We've reached our final destination!
# ASSUMPTION: no edge port will send it back out into the network...
# use the inverse T trick to get original headerspace which led us here
original_headers = find_loop_original_header(NTF,TTF,p_node)
for original_header in original_headers:
key = (original_header, start_port)
if not key in port_omega:
# TODO: python default value for hash?
port_omega[key] = []
port_omega[key].append((next_h, next_p))
linked = TTF.T(next_h,next_p)
if not linked:
sys.stdout.write("\n")
for (linked_h,linked_ports) in linked:
for linked_p in linked_ports:
print " -> %s" % (port_to_hex(linked_p))
new_p_node = {}
new_p_node["hdr"] = linked_h
new_p_node["port"] = linked_p
new_p_node["visits"] = list(p_node["visits"])
new_p_node["visits"].append(p_node["port"])
new_p_node["hs_history"] = list(p_node["hs_history"])
new_p_node["hs_history"].append(p_node["hdr"])
if linked_p in new_p_node["visits"]:
print "WARNING: detected a loop - branch aborted: \nHeaderSpace: %s\n Visited Ports: %s\nLast Port %s "%(\
new_p_node["hdr"],ports_to_hex(new_p_node["visits"]),hex(new_p_node["port"]))
return port_omega
else:
tmp_propag.append(new_p_node)
propagation = tmp_propag
return port_omega
