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Commit 484dd59a authored by jo2-holdsworth's avatar jo2-holdsworth
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task 2 and 3

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with 46 additions and 136 deletions
udp.py
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− 136
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......@@ -12,9 +12,46 @@ async def main():
message = await websocket.recv()
udp = decodePacket(message)
printUDPPacket(udp)
compute_checksum(udp['Source Port'],udp['Dest Port'],udp['Server Sent'][8:(len(udp['Server Sent'])+8)],udp['Data Length'])
compute_checksum(udp['Source Port'],udp['Dest Port'],udp['Server Sent'][8:(len(udp['Server Sent'])+8)])
#print(f"calculated checksum: {int(compute_checksum(2,1,b'AB'),2)}")
print(bin(udp['Checksum']))
async def mainSend():
uri = "ws://localhost:5612"
async with websockets.connect(uri) as websocket:
await recv_and_decode_packet(websocket)
while True:
await send_packet(websocket, 0, 542, b'1111')
await recv_and_decode_packet(websocket)
time.sleep(1)
async def recv_and_decode_packet(websocket):
message = await websocket.recv()
print("here")
print(decodePacket(message))
async def send_packet(websocket, sourcePort, destPort, payload):
print(type(payload))
checkSum = compute_checksum(sourcePort, destPort, payload)
print(checkSum)
destPort = destPort.to_bytes(2, 'little')
sourcePort = sourcePort.to_bytes(2, 'little')
length = 8 + len(payload)
length = length.to_bytes(2, 'little')
checkSum = checkSum.to_bytes(2, 'little')
print(f"length : {length}")
packet = sourcePort + destPort + length + checkSum + payload
print(destPort + sourcePort)
packet = base64.b64encode(packet)
await websocket.send(packet)
def decodePacket(response):
decoded = {}
decoded['Base64'] = response
......@@ -33,15 +70,15 @@ def printUDPPacket(dict):
for key, value in dict.items():
print(f"{key}: {value}")
def compute_checksum(sourcePort, destPort, payload, length):
def compute_checksum(sourcePort, destPort, payload):
print(sourcePort)
print(destPort)
print(payload)
print(length)
sourcePort = sourcePort.to_bytes(2, 'little')
destPort = destPort.to_bytes(2, 'little')
length = length.to_bytes(2, 'little')
length = (len(payload)+8).to_bytes(2, 'little')
calc = sourcePort + destPort + length + bytes(2) + payload
......@@ -57,147 +94,20 @@ def compute_checksum(sourcePort, destPort, payload, length):
tmp = (calc[i] << 8) + calc[i+1]
sum += tmp
sum = (sum << 16) + (sum & 0xFF)
sum = (sum >> 16) + (sum & 0xFFFF)
sum = ~sum & 0xFFFF
sum = int(format(sum,'b'),2)
return sum
return ~sum
# payload = bytearray(payload)
print(type(payload))
# if (len(payload) % 2) != 0:
# print("0")
# payload.append(bytes())
x = 0
i = 0
print(len(payload))
j = (len(payload) // 2)*2
print(j)
while i < j:
x = format(payload[i],"b")
for n in range(0,8 - len(x)): #n note used
x = "0" + x
y = format(payload[i+1],"b")
for n in range(0,8 - len(y)):
y = "0" + y
z = x + y
z = "0b" + z
print(f"x: {x}")
print(f"y: {y}")
print(f"z: {z}")
calc = calc + int(z,2)
print(f"int of z: {int(z,2)}")
print(f"calc after calc: {calc}")
i += 2
if len(payload) % 2 != 0:
print(f"i: {i}")
x = format(payload[i],"b")
for f in range(0,8 - len(x)):
x = "0" + x
print(f"payload: {payload[i]}")
y = "00000000"
z = x + y
print(x)
print(z)
z = "0b" + z
calc = calc + int(z,2)
# while i <= len(payload):
# x = format(payload[i],"b")
# for n in range(0,8 - len(x)): #n note used
# x = "0" + x
# y = format(payload[i+1],"b")
# for n in range(0,8 - len(z)):
# z = "0" + z
# z = x + y
# z = "0b" + z
# calc = calc + int(z,2)
# print(calc)
# i += 2
# else:
# print("heres")
# j = (len(payload) // 2)*2
# print(j)
# while i < j:
# x = format(payload[i],"b")
# for n in range(0,8 - len(x)): #n note used
# print("hereres")
# x = "0" + x
# y = format(payload[i+1],"b")
# print(f"y: {y}")
# for n in range(0,8 - len(y)):
# print("okkk")
# y = "0" + y
# z = x + y
# print(f"length of z: {len(z)}")
# z = "0b" + z
# calc = calc + int(z,2)
# print(calc)
# i += 2
# print(f"i: {i}")
# x = format(payload[i],"b")
# for f in range(0,8 - len(x)):
# x = "0" + x
# print(f"payload: {payload[i]}")
# y = "00000000"
# z = y + x
# print(x)
# print(z)
# z = "0b" + z
# calc = calc + int(z,2)
# for byte in payload:
# x = + 1
# print(type(byte))
# z = format(byte,"b")
# calcPayload += z
# calcPayload = "0b" + calcPayload
# if x % 2 != 0:
# calcPayload +="00000000"
# print("here")
print(f"before calc: {calc}")
print(format(calc,"b"))
flipped = ""
calc = calc & 0xFFFF
print(type(calc))
calc = format(calc, "b")
print(f"after calc1: {calc}")
for f in range(0,16 - len(calc)):
calc = "0" + calc
print(f"after calc2: {calc}")
print(int(calc,2))
# print(format(calc,"b"))
# calcPayload = bin(calc)
for bit in calc:
if bit == "1":
flipped += "0"
elif bit == "0":
flipped += "1"
# flipped += bit
print(flipped)
print(int(flipped,2))
#mod odd number then add 8 0's
async def recv_message(websocket):
message = json.loads(await websocket.recv())
return message['payload']
# 0000 0000 0111 0010
# 1111 1101 1111 0111
# 0000 0010 0000 1000
# 0111 0110 0110 0101
# 0111 0110 0110 0101
# 1101 1111 0000 101
# 1101 1111 0000 101
# 0110 1111 1000 0101
#1001 0000 0111 1010
# 0111 0010 0000 0000
#0011 1011 1100 1011
# 1100 0100 0011 0100
if __name__ == "__main__":
print("Echo client")
# while 1:
asyncio.run(main())
asyncio.run(mainSend())
time.sleep(10)
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