def discover_existing_mcastport(ring1, timeout = 10):
console_log.debug("Sniffing for packets to %s on %s (%s)" % (ring1.mcastaddr, ring1.name, ring1.ipv4_address))
console_log.debug("Sniffing for packets to %s on %s" % (ring1.mcastaddr, ring1.name))
networking.subscribe_multicast(ring1)
cap = networking.start_cap(ring1,
timeout / 10,
"ip multicast and dst host %s and not src host %s" % (ring1.mcastaddr,
ring1.ipv4_address))
# Stop the talker thread if it is running.
_stop_talker_thread()
ring1_original_mcast_port = ring1.mcastport
def recv_packets(header, data):
ring1.mcastport = networking.get_dport_from_packet(data)
console_log.debug("Sniffed multicast traffic on %d" % ring1.mcastport)
try:
packet_count = 0
start_time = time.time()
while packet_count < 1 and time.time() < start_time + timeout:
try:
packet_count += cap.dispatch(1, recv_packets)
except Exception, e:
raise RuntimeError("Error reading from the network: %s" %
str(e))
# If we haven't seen anything yet, make sure we are blathering...
if packet_count < 1:
_start_talker_thread(ring1)
console_log.debug("Finished after %d seconds, sniffed: %d" % (time.time() - start_time, packet_count))
def find_unused_port(ring0, timeout=10, batch_count=10000):
from random import choice
dest_addr = ring0.mcastaddr
port_min = 32767
port_max = 65535
ports = range(port_min, port_max, 2)
portrange_str = "%s-%s" % (port_min, port_max)
firewall_control.add_rule(
0, "tcp", "find unused port", persist=False, address=ring0.mcastaddr
)
try:
networking.subscribe_multicast(ring0)
console_log.info(
"Sniffing for packets to %s on %s within port range %s"
% (dest_addr, ring0.name, portrange_str)
)
cap = networking.start_cap(
ring0,
timeout,
"host %s and udp and portrange %s" % (dest_addr, portrange_str),
)
def recv_packets(header, data):
tgt_port = networking.get_dport_from_packet(data)
try:
ports.remove(tgt_port)
except ValueError:
# already removed
pass
packet_count = 0
start = time.time()
while time.time() - start < timeout:
try:
packet_count += cap.dispatch(batch_count, recv_packets)
except Exception as e:
raise RuntimeError("Error reading from the network: %s" % str(e))
console_log.info(
"Finished after %d seconds, sniffed: %d"
% (time.time() - start, packet_count)
)
finally:
firewall_control.remove_rule(
0, "tcp", "find unused port", persist=False, address=ring0.mcastaddr
)
return choice(ports)
def run(self):
self.log.debug("Talker thread running")
sock = networking.subscribe_multicast(self.interface)
while not self._stop.is_set():
sock.sendto("%d\n\0" % self.interface.mcastport,
(self.interface.mcastaddr, self.interface.mcastport))
self._stop.wait(0.25)
