def handle_packet(self, incoming_intf, packet):
"""Forwards an IP packet from the simulated topology to the network."""
if len(packet) >= 34 and packet[12:14] == '\x08\x00':
dst_ip = packet[30:34]
if not MAY_FORWARD_TO_PRIVATE_IPS and self.__is_private_address(dst_ip):
logging.debug('%s ignoring IP packet to private address space: %s' % (self.di(), inet_ntoa(dst_ip)))
return
if len(packet) >= 42 and packet[12:14] == '\x08\06' and self.topo.gw_intf_to_first_hop:
pkt = ProtocolHelper.Packet(packet)
if pkt.is_arp_reply() and pkt.dha == self.topo.gw_intf_to_first_hop.mac:
logging.debug('%s: handling ARP reply from first hop to gateway' % self.di())
self.topo.update_arp_translation(pkt.spa, pkt.sha)
return
# forward packet out to the real network
if self.raw_socket:
try:
logging.debug('%s sending packet out to the real world: %s' % (self.di(), pktstr(packet)))
self.topo.stats.note_pkt_from_topo(len(packet))
self.raw_socket.send(packet)
except socket.error:
# this is recoverable - the network may come back up
log_exception(logging.WARN,
'unable to forward packet to the real network')
def start_topology(self, tid, client_ip, user):
"""Handles starting up the specified topology id. Returns a 2-tuple.
The first element is None and the second is a string if an error occurs;
otherwise the first element is the topology."""
try:
topo = DBService.run_and_wait(lambda: Topology(tid, self.raw_socket, client_ip, user))
topo.interactors = [] # list of TI connections to this topo
except TopologyCreationException as e:
return (None, str(e))
except db.Topology.DoesNotExist:
return (None, 'topology %d does not exist' % tid)
except db.IPAssignment.DoesNotExist:
return (None, 'topology %d is missing an IP assignment' % tid)
except db.IPBlockAllocation.DoesNotExist:
return (None, 'topology %d is not allocated any IPs' % tid)
except AddressAllocation.IPError:
return (None, 'not enough IPs to allocate for topology %d' % tid)
except:
msg = 'topology instantiation unexpectedly failed'
log_exception(logging.ERROR, msg)
return (None, msg)
if topo.has_gateway():
self.resolver.register_topology(topo)
with self.topologies_lock:
self.topologies[tid] = topo
self.topologies_changed = True
return (topo, None)
def start_topology(self, tid, client_ip, user):
"""Handles starting up the specified topology id. Returns a 2-tuple.
The first element is None and the second is a string if an error occurs;
otherwise the first element is the topology."""
try:
topo = Topology(tid, self.raw_socket, client_ip, user)
topo.interactors = [] # list of TI connections to this topo
except TopologyCreationException as e:
return (None, str(e))
except db.Topology.DoesNotExist:
return (None, 'topology %d does not exist' % tid)
except db.IPAssignment.DoesNotExist:
return (None, 'topology %d is missing an IP assignment' % tid)
except db.IPBlockAllocation.DoesNotExist:
return (None, 'topology %d is not allocated any IPs' % tid)
except:
msg = 'topology instantiation unexpectedly failed'
log_exception(logging.ERROR, msg)
return (None, msg)
if topo.has_gateway():
self.resolver.register_topology(topo)
with self.topologies_lock:
self.topologies[tid] = topo
self.topologies_changed = True
return (topo, None)
def handle_packet(self, incoming_intf, packet):
"""Forwards an IP packet from the simulated topology to the network."""
if len(packet) >= 34 and packet[12:14] == '\x08\x00':
dst_ip = packet[30:34]
if not MAY_FORWARD_TO_PRIVATE_IPS and self.__is_private_address(dst_ip):
logging.debug('%s ignoring IP packet to private address space: %s' % (self.di(), inet_ntoa(dst_ip)))
return
if len(packet) >= 42 and packet[12:14] == '\x08\06' and self.topo.gw_intf_to_first_hop:
pkt = ProtocolHelper.Packet(packet)
if pkt.is_arp_reply() and pkt.dha == self.topo.gw_intf_to_first_hop.mac:
logging.debug('%s: handling ARP reply from first hop to gateway' % self.di())
self.topo.update_arp_translation(pkt.sha)
return
# forward packet out to the real network
if self.raw_socket:
try:
logging.debug('%s sending packet out to the real world: %s' % (self.di(), pktstr(packet)))
self.topo.stats.note_pkt_from_topo(len(packet))
self.raw_socket.send(packet)
except socket.error:
# this is recoverable - the network may come back up
log_exception(logging.WARN,
'unable to forward packet to the real network')
def __start_raw_socket(self, dev):
"""Starts a socket for sending raw Ethernet frames."""
try:
self.raw_socket = socket.socket(socket.PF_PACKET, socket.SOCK_RAW)
self.raw_socket.bind((dev, 0x9999))
except socket.error as e:
if e.errno == errno.EPERM:
extra = ' (did you forget to run me with root?)'
else:
extra = ''
log_exception(logging.CRITICAL, 'failed to open raw socket' + extra)
sys.exit(-1)
def __start_raw_socket(self, dev):
"""Starts a socket for sending raw Ethernet frames."""
try:
self.raw_socket = socket.socket(socket.PF_PACKET, socket.SOCK_RAW)
self.raw_socket.bind((dev, 0x9999))
except socket.error as e:
if e.errno == errno.EPERM:
extra = ' (did you forget to run me with root?)'
else:
extra = ''
log_exception(logging.CRITICAL, 'failed to open raw socket' + extra)
sys.exit(-1)
def __run_pcap(self, dev):
"""Start listening for packets coming in from the outside world."""
MAX_LEN = 2000 # max size of packet to capture
PROMISCUOUS = 1 # promiscuous mode?
READ_TIMEOUT = 100 # in milliseconds
MAX_PKTS = -1 # number of packets to capture; -1 => no limit
# the method which will be called when a packet is captured
def ph(_, data):
# thread safety: call from the main twisted event loop
reactor.callFromThread(self.handle_packet_from_outside, data)
# start the packet capture
try:
p = open_live(dev, MAX_LEN, PROMISCUOUS, READ_TIMEOUT)
except PcapError:
log_exception(logging.CRITICAL, 'failed to start pcap')
sys.exit(-1)
p.setfilter(PCAP_FILTER)
logging.info("Listening on %s: net=%s, mask=%s, filter=%s" % (dev, p.getnet(), p.getmask(), PCAP_FILTER))
p.loop(MAX_PKTS, ph)
def __run_pcap(self, dev):
"""Start listening for packets coming in from the outside world."""
MAX_LEN = 2000 # max size of packet to capture
PROMISCUOUS = 1 # promiscuous mode?
READ_TIMEOUT = 100 # in milliseconds
MAX_PKTS = -1 # number of packets to capture; -1 => no limit
# the method which will be called when a packet is captured
def ph(_, data):
# thread safety: call from the main twisted event loop
reactor.callFromThread(self.handle_packet_from_outside, data)
# start the packet capture
try:
p = open_live(dev, MAX_LEN, PROMISCUOUS, READ_TIMEOUT)
except PcapError:
log_exception(logging.CRITICAL, 'failed to start pcap')
sys.exit(-1)
p.setfilter(PCAP_FILTER)
logging.info("Listening on %s: net=%s, mask=%s, filter=%s" % (dev, p.getnet(), p.getmask(), PCAP_FILTER))
p.loop(MAX_PKTS, ph)
