def printIcmpPacket(self, packet):
pkt = headers.IcmpHeader()
try:
pkt.decode(packet)
print("--------------------------------")
print("ICMP Header")
print("--------------------------------")
print(str(pkt))
except RuntimeError:
print("...cant print icmp, invalid type")
finally:
pass
def test_icmp(self):
"""Check IcmpHeader"""
h1 = headers.IcmpHeader(TestHeaders.EtherIpIcmpHddr[34:])
h2 = headers.IcmpHeader()
offset = h2.decode(TestHeaders.EtherIpIcmpHddr[34:])
self.assertEqual(offset, 64)
self.assertEqual(str(h1), str(h2))
self.assertEqual(
str(h1),
r"""IcmpHeader: type=0 code=0 sum=26887 id=50522 seqNum=2 data=b']\xd1\x98\x7f\x00\x01\xf0F\x08\t\n\x0b\x0c\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !"#$%&\'()*+,-./01234567'"""
)
self.assertEqual(h1.type, 0)
self.assertEqual(h1.code, 0)
self.assertEqual(h1.sum, 26887)
self.assertEqual(h1.id, 50522)
self.assertEqual(h1.seqNum, 2)
self.assertEqual(
h1.data,
b']\xd1\x98\x7f\x00\x01\xf0F\x08\t\n\x0b\x0c\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !"#$%&\'()*+,-./01234567'
)
self.assertEqual(len(h1.data), 56)
h3 = headers.IcmpHeader(
type=0,
code=0,
sum=26887,
id=50522,
seqNum=2,
data=
b']\xd1\x98\x7f\x00\x01\xf0F\x08\t\n\x0b\x0c\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f !"#$%&\'()*+,-./01234567'
)
self.assertEqual(len(h3.encode()), 64)
self.assertEqual(str(h1), str(h3))
self.assertEqual(h3.encode(), TestHeaders.EtherIpIcmpHddr[34:34 + 64])
def handleArpRequest(self): # add more params as needed
'''
IMPLEMENT THIS METHOD
This method should handle sending ARP requests if necessary.
The high-level logic:
if now - req->timeSent > seconds(1)
if req->nTimesSent >= 5:
send icmp host unreachable to source addr of all pkts waiting
on this request
cache.removeRequest(req)
else:
send arp request
req->timeSent = now
req->nTimesSent++
'''
if (time.localtime - self.timeSent) > 1:
if self.nTimesSent >= 5:
pkt = headers.IcmpHeader(code=1)
buf = pkt.encode()
pass
def echoIcmp(self, packet, iface):
print("...Starting echo process")
self.printEthPacket(packet)
ethPkt = headers.EtherHeader()
decodeLength = ethPkt.decode(packet)
temp = ethPkt.dhost
ethPkt.dhost = ethPkt.shost
ethPkt.shost = temp
ipPkt = headers.IpHeader()
ipDecodeLength = ipPkt.decode(packet[decodeLength:])
temp = ipPkt.dst
ipPkt.dst = ipPkt.src
ipPkt.src = temp
pkt = headers.IcmpHeader()
icmpDecode = pkt.decode(packet[decodeLength + ipDecodeLength:])
if len(packet[decodeLength + ipDecodeLength + icmpDecode:]) > 0:
pkt.type = 3
pkt.code = 3
else:
pkt.type = 0
pkt.sum = 0
checksum = utils.checksum(pkt.encode())
pkt.sum = checksum
#print (str(pkt))
#print(ethPkt.shost)
buf = ethPkt.encode() + ipPkt.encode() + pkt.encode(
) + packet[decodeLength + ipDecodeLength + icmpDecode:]
outface = self.findIfaceByMac(ethPkt.shost)
self.printEthPacket(buf)
print("...sending icmp packet through interface: " + str(outface.name))
#self.printEthPacket(buf)
self.sendPacket(buf, outface.name)
def ipProcess(self, packet, iface):
print("...started ipv4 process")
ethPkt = headers.EtherHeader()
decodeLength = ethPkt.decode(packet)
ipPkt = headers.IpHeader()
ipDecode = ipPkt.decode(packet[decodeLength:])
inface = self.findIfaceByIp(ipPkt.dst)
if inface:
self.echoIcmp(packet, inface)
else:
ipPkt.ttl = ipPkt.ttl - 1
ipPkt.sum = 0
checksum = utils.checksum(ipPkt.encode())
ipPkt.sum = checksum
if ipPkt.ttl < 1:
pkt = headers.IcmpHeader()
#icmpDecode = pkt.decode(packet[decodeLength + ipDecode:])
pkt.type = 11
pkt.code = 0
checksum = utils.checksum(pkt.encode())
pkt.sum = checksum
buf = ethPkt.encode() + ipPkt.encode() + pkt.encode(
) + packet[decodeLength + ipDecode:]
outface = self.findIfaceByMac(ethPkt.dhost)
self.sendPacket(buf, outface.name)
if (self.arpCache.lookup(ipPkt.dst) != None):
print("...looking for packet destination: " + str(ipPkt.dst))
print("...return from routing table lookup: " +
str(self.routingTable.lookup(str(ipPkt.dst))))
if (self.routingTable.lookup(str(ipPkt.dst)) != None):
print("...checking queue")
while self.queue:
queuePkt = self.queue.pop(0)
print("--------------------------------")
print("...processing queue packet:")
self.printEthPacket(queuePkt)
tempEth = headers.EtherHeader()
tempDecodeLength = tempEth.decode(queuePkt)
tempIpPkt = headers.IpHeader()
tempIpDecode = tempIpPkt.decode(
queuePkt[tempDecodeLength:])
tempIpPkt.ttl = tempIpPkt.ttl - 1
tempIpPkt.sum = 0
checksum = utils.checksum(tempIpPkt.encode())
tempIpPkt.sum = checksum
inface = self.findIfaceByIp(tempIpPkt.dst)
outface = self.routingTable.lookup(str(tempIpPkt.dst))
#self.printEthPacket(packet)
tempEth.shost = self.findIfaceByName(outface).mac
tempEth.dhost = self.arpCache.lookup(tempIpPkt.dst).mac
outPkt = tempEth.encode() + tempIpPkt.encode(
) + queuePkt[tempDecodeLength + tempIpDecode:]
#print("...out packet: ")
#self.printEthPacket(outPkt)
self.sendPacket(outPkt, outface)
print("...queue is empty")
outface = self.routingTable.lookup(str(ipPkt.dst))
#self.printEthPacket(packet)
ethPkt.shost = self.findIfaceByName(outface).mac
ethPkt.dhost = self.arpCache.lookup(ipPkt.dst).mac
outPkt = ethPkt.encode() + ipPkt.encode(
) + packet[decodeLength + ipDecode:]
#print("...out packet: ")
#self.printEthPacket(outPkt)
self.sendPacket(outPkt, outface)
else:
self.queue.append(packet)
if len(self.queue) > 4:
while self.queue:
queuePkt = self.queue.pop(0)
print("--------------------------------")
print("...processing unreachable host queue packet:")
self.printEthPacket(queuePkt)
tempEth = headers.EtherHeader()
tempDecodeLength = tempEth.decode(queuePkt)
tempEth.dhost = tempEth.shost
tempEth.shost = iface.mac
tempIpPkt = headers.IpHeader()
tempIpDecode = tempIpPkt.decode(
queuePkt[tempDecodeLength:])
tempIpPkt.dst = tempIpPkt.src
tempIpPkt.src = iface.ip
tempIcmp = headers.IcmpHeader()
tempIcmpDecode = tempIcmp.decode(
queuePkt[tempDecodeLength + tempIpDecode:])
tempIcmp.type = 3
tempIcmp.code = 0
tempIcmp.sum = 0
checksum = utils.checksum(tempIcmp.encode())
tempIcmp.sum = checksum
tempIpPkt.sum = 0
checksum = utils.checksum(tempIpPkt.encode())
tempIpPkt.sum = checksum
outface = iface.name
#self.printEthPacket(packet)
outPkt = tempEth.encode() + tempIpPkt.encode(
) + tempIcmp.encode() + queuePkt[tempDecodeLength +
tempIpDecode +
tempIcmpDecode:]
#print("...out packet: ")
#self.printEthPacket(outPkt)
self.printEthPacket(outPkt)
self.sendPacket(outPkt, outface)
else:
for ifc in self.ifaces:
if ifc.name != iface.name:
searchArpPkt = headers.ArpHeader(
hln=6,
pln=4,
op=1,
sha=ifc.mac,
sip=ifc.ip,
tha="FF:FF:FF:FF:FF:FF",
tip=ipPkt.dst)
buf = searchArpPkt.encode()
replyEthPkt = headers.EtherHeader(
shost=ifc.mac,
dhost="FF:FF:FF:FF:FF:FF",
type=2054)
buf = replyEthPkt.encode() + buf
print("--------------------------------")
print("...sending arp request to interface " +
ifc.name)
#self.printEthPacket(buf)
self.sendPacket(buf, ifc.name)
#while True:
# if self.arpCache.lookup(pkt.dst) != None:
# print("...looking for packet destination: " + str(pkt.dst))
# print("...return from routingtable lookup: " + str(self.routingTable.lookup(str(pkt.dst))))
# if(self.routingTable.lookup(str(pkt.dst)) != None):
# outface = self.routingTable.lookup(str(pkt.dst))
# outmac = self.arpCache
# #self.printEthPacket(packet)
# ethPkt.shost = self.findIfaceByName(outface).mac
# ethPkt.dhost = self.arpCache.lookup(pkt.dst).mac
# outPkt = ethPkt.encode() + packet[decodeLength:]
# #print("...out packet: ")
# #self.printEthPacket(outPkt)
# self.sendPacket(outPkt,outface)
# break
#
#
#if self.arpCache.lookup(pkt.dst) == None:
# print ("Adding to cache" + str(self.arpCache.queueRequest(pkt.dst, pkt, iface)))
# self.routingTable.lookup(str(pkt.dst))
#else:
# print("Exists in the cache: " + str(self.arpCache.lookup(pkt.dst)))
pass