def Post_Msg(cli):
os.system('clear')
tweet = raw_input('\tEnter your tweet: ')
send_sock.sendall(ip_checksum('Post Tweet') + 'Post Tweet')
send_sock.sendall(cli + ': ' + tweet)
menu(cli)
return
def Offline_Msg(cli):
os.system('clear')
has_answered = False
while not has_answered:
send_sock.sendall(ip_checksum("Offline_messages_request") + 'Offline_messages_request')
try:
message = send_sock.recv(4096)
except timeout:
print '\tTimeout - Sever busy'
continue
else:
has_answered = True
ret = json.loads(message)
MsgList = ret["msglist"]
print '\n\t********************'
print '\n\t' + cli + ' List of Messages:'
print '\n\t'
if MsgList == 'No Messages Received':
print MsgList
else:
for i in range(0, len(MsgList)):
print MsgList[i]
print '\n'
menu(cli)
return
def checksum_valid(chk, seq, header, data):
checksum = pack('IH' + str(len(data)) + 's', seq, header, data)
if ip_checksum(checksum) == chk:
return True
else:
return False
def read_choice(cli):
print '\n\t****************************'
choice = int(raw_input('\n\tPick a menu option: '))
print '\n\t****************************'
if choice == 1:
Offline_Msg(cli)
elif choice == 2:
Edit_Sub(cli)
elif choice == 3:
Post_Msg(cli)
elif choice == 4:
print '\n\t***GoodBye***\n\tLogging You Out'
has_received = False
while not has_received:
send_sock.sendall(ip_checksum('Logging Out') + 'Logging Out')
reply = send_sock.recv(4096)
if reply == 'success':
has_received = True
send_sock.close()
elif choice == 5:
Hashtag_Search(cli)
elif choice == 6:
See_followers(cli)
elif choice == 7:
Send_Msgs(cli)
elif choice == 8:
Del_Friend_Msgs(cli)
elif choice == 9:
Del_All_Msgs(cli)
def checksum_valid(chk, seq, header, data):
checksum = pack('IH'+str(len(data))+'s', seq, header, data)
if ip_checksum(checksum) == chk:
return True
else:
return False
def chkpckt(pckt):
pckt_seq = pckt[0:1]
pckt_chksum = pckt[1:3]
pckt_msg = pckt[3:]
if pckt_chksum == ip_checksum(pckt_msg):
return (True, pckt_seq, pckt_msg)
else:
return (False, pckt_seq, pckt_msg)
def mkpkt(seqNum, data):
global isCorrupt
chksum = ip_checksum(str(data))
if isCorrupt == 1 and data == 1:
isCorrupt = 0
chksum = 'corrupted'
pkt = str(seqNum) + str(data) + chksum
return pkt
def login_verification():
msg_count = 0
while True:
connection, address = recv_sock.accept()
message = connection.recv(4096)
checksum = message[:2]
if not ip_checksum(message[2:]) == message[:2]:
continue
else:
s = message[2:]
temp = []
temp = s.split(':')
if len(temp) == 2:
name, password = temp[0], temp[1]
found = False
for cli in cli_list:
if cli == [name, password]:
found = True
break
if not found:
connection.sendall(ip_checksum('Invalid') + 'Invalid')
print '\n\t' + name + ' Connection attempt failed\n'
else:
print '\n\t' + name + ' Successfully Logged in\n'
connection.sendall(ip_checksum('Valid') + 'Valid')
connections[user_id(name)].append(connection)
recv_sock.listen(1)
live_sock, address = recv_sock.accept()
connections[user_id(name)].append(live_sock)
print len(connections[user_id(name)])
print '\t' + name + ' Live socket connected'
#recv_sock.listen(5)
t = threading.Thread(target = user_handler, args=(name, connection,))
t.daemon = True
threads.append(t)
t.start()
recv_sock.close()
def Del_All_Msgs(cli):
os.system('clear')
send_sock.sendall(ip_checksum('Del_All_Msgs') + 'Del_All_Msgs')
has_succeeded = False
while not has_succeeded:
reply = send_sock.recv(4096)
if reply == 'success':
has_succeeded = True
menu(cli)
return
def makepkt(num, data):
global iscorrupt
if iscorrupt == 1 and data == 1:
iscorrupt = 0
checksum = 'corrupted'
else:
checksum = ip_checksum(str(data))
packet = str(num) + str(data) + checksum
return packet
def makepkt(num, data):
global iscorrupt
if iscorrupt == 1 and data == 2:
iscorrupt = 0
checksum = 'corrupted'
print "packet " + str(data) + "is corrupted, sending "
else:
checksum = ip_checksum(str(data))
packet = str(num) + str(data) + checksum
return packet
def make_packet(seq_num, message):
"""
Creates a packet using the sequence number and data provided.
Calculates checksum of data add concatenates it with data.
Returns a single string containing sequence number, data, and
checksum, in that order.
"""
tmp = str(seq_num) + message
checksum = ip_checksum(tmp)
final_packet = tmp + checksum
return final_packet
def sendwithcheck(sock, msg, to):
checksum = ip_checksum(msg)
tosend = checksum+msg
rand = random.randint(1, 20)
if rand >= 1 and rand <= 5:
print("Dropped")
return
rand_sleep()
sock.sendto(tosend, to)
def sendwithcheck(sock, msg, to):
checksum = ip_checksum(msg)
tosend = checksum + msg
rand = random.randint(1, 20)
if rand >= 1 and rand <= 5:
print("Dropped")
return
rand_sleep()
sock.sendto(tosend, to)
def authenticate():
os.system('clear')
print '\t***************************'
cli_name = raw_input('\tUsername: '******'\tPassword: '******'\t***************************'
print '\n\t****Waiting for server to authenticate your login****\n'
authentication = cli_name
authentication += ':' + cli_pwd
ans_received = False
while not ans_received:
send_sock.sendall(ip_checksum(authentication) + authentication)
try:
message = send_sock.recv(4096)
except timeout:
print 'Timeout occured -- Server Busy'
continue
else:
if not message[:2] == ip_checksum(message[2:]):
continue #resend the authentication to server
else:
ans_received = True
if message[2:] == 'Valid':
os.system('clear')
print '\n\tSuccessful Login!! -- Welcome ' + cli_name
live_sock = socket(AF_INET, SOCK_STREAM)
live_sock.connect(dest)
t = threading.Thread(target = tweets_and_msgs_handler, args=(cli_name, live_sock, ))
t.daemon = True
t.start()
menu(cli_name)
elif message[2:] == 'Invalid':
print '\n\tError: Name or Password entered is invalid -- Try again'
authenticate()
send_sock.close()
def corrupt(packet):
"""
Checks if packet was corrupted during transmission. Calculates
checksum and compares it to the one included in the packet.
Returns true if data is corrupted, false otherwise.
"""
data = packet[:len(packet) - 2]
checksum = packet[len(packet) - 2:]
calculated_check = ip_checksum(data)
if checksum != calculated_check:
return True
return False
def tick(self): # Progress all games for game in self.db.ongoing_games: if game.ongoing : game.tick() else : self.db.ongoing_games.remove(game) #Receive data from client. readable, writable, exceptional = select.select([self.s], [], [], 0); d = None self.data = "" self.reply = "" if readable: d = self.s.recvfrom(1024) data = d[0] self.addr = d[1] self.source = str(d[1]) # print 'Handled player request' elif not self.data_q.empty(): d = self.data_q.get(False) # print 'Host packet contents : ' + d self.route_msg(d) return else: return # Take apart packet self.ack = data[4] msg = data[5:-2] chksum = data[-2:] ''' print 'OK... \n' + \ 'Source Port : ' + self.source + '\n' \ 'Ack : ' + self.ack + '\n' + \ 'Data : ' + msg + '\n'# + \ # 'Checksum : [' + chksum + ']'; ''' # print 'This checksum : [' + ip_checksum(msg) + ']' if ip_checksum(msg) == chksum: # Not corrupt # print 'Routing message to correct control code.' self.route_msg(msg) self.ack = '0' if (self.ack == '0') else '1' else: self.ack = '1' if (self.ack == '1') else '0' #print 'Denying packet for 7.5 seconds...' #time.sleep(7.5); reply = 'ACK' + self.ack + '\n' + str(self.data); # print 'Sending reply : ' + reply self.s.sendto(reply, (self.addr[0], self.addr[1]));
def Edit_Sub(cli):
os.system('clear')
print("""\n
\t1. Add Subscription
\t2. Delete Subscription
""")
choice = int(raw_input('\n\tEnter Your Choice: '))
if choice == 1:
send_sock.sendall(ip_checksum('Subscribe') + 'Subscribe')
friend = raw_input('\n\tEnter Friend to Subscribe to: ')
has_succeeded = False
while not has_succeeded:
send_sock.sendall(cli+friend)
reply = send_sock.recv(4096)
if reply == 'success':
has_succeeded = True
elif choice == 2:
send_sock.sendall(ip_checksum('Unsubscribe') + 'Unsubscribe')
reply = send_sock.recv(4096)
list = json.loads(reply)
sublist = list["list"]
if sublist == 'No followers':
print '\tNo user to Unsubscribe from'
else:
for l in sublist:
print l
friend = raw_input('\n\tEnter Friend to Unsubcribe from: ')
has_succeeded = False
while not has_succeeded:
send_sock.sendall(cli+friend)
reply = send_sock.recv(4096)
if reply == 'success':
has_succeeded = True
menu(cli)
return
def Del_Friend_Msgs(cli):
os.system('clear')
send_sock.sendall(ip_checksum('Del_Friend_Msgs') + 'Del_Friend_Msgs')
friend = raw_input("\tEnter friend whose messages to delete: ")
has_succeeded = False
while not has_succeeded:
send_sock.sendall(cli + ':' + friend)
reply = send_sock.recv(4096)
if reply == 'success':
has_succeeded = True
menu(cli)
return
def See_followers(cli):
os.system('clear')
send_sock.sendall(ip_checksum('See Followers') + 'See Followers')
reply = send_sock.recv(4096)
msg = json.loads(reply)
subList = msg["subList"]
print '\n\t' + cli + ' List of Followers: '
if subList == 'No Followers':
print subList
else:
for i in range(0, len(subList)):
print subList[i]
print '\n'
menu(cli)
return
def Hashtag_Search(cli):
os.system('clear')
send_sock.sendall(ip_checksum('Hashtag Search') + 'Hashtag Search')
hashtag = raw_input('\tEnter the hashtag to search for: ')
send_sock.sendall(hashtag)
reply = send_sock.recv(4096)
msg = json.loads(reply)
hashList = msg["hashList"]
print '\n\t' + cli + ' List of tweets containing ' + hashtag + ':'
if hashList == 'No Tweets Found':
print hashList
else:
for i in range(0, len(hashList)):
print hashList[i]
print '\n'
menu(cli)
return
def Send_Msgs(cli):
os.system('clear')
send_sock.sendall(ip_checksum('Send Message') + 'Send Message')
destinator = raw_input('\n\tEnter destinator: ')
msg = raw_input('\tEnter Message: ')
while len(msg) > 140:
print '\n\tMessage longer than 140 characters -- try again'
msg = raw_input('\tEnter Message: ')
has_succeeded = False
while not has_succeeded:
send_sock.sendall(destinator + cli + ': ' + msg)
reply = send_sock.recv(4096)
if reply == 'success':
has_succeeded = True
menu(cli)
return
def checksum_cmp (received_content, received_checksum):
#casting checksum to str by itself is not the same when casting it to str via tuple...
#when checksum is in tuple and is cast into a string, they are the same
check = ip_checksum(received_content)
tuple_pkt = (0,0, check)
tuple_pkt_str = str(tuple_pkt)
splice_tuple_pkt = string.split(tuple_pkt_str, ',')
j = 0
for i in splice_tuple_pkt:
i = string.strip(i, '(')
i = string.strip(i, ')')
i = string.strip (i) #by default it removes whitespace
i = string.strip (i, '\'')
splice_tuple_pkt[j] = i
j = j + 1
if splice_tuple_pkt[2] == received_checksum:
return 1
else:
return 0
print('Socket bind complete')
expecting_seq = 0
#now keep talking with the client
while 1:
# receive data from client (data, addr)
msg, addr = s.recvfrom(1024)
#msg = msg.decode('utf-8')
checksum = msg[:2]
seq = msg[2]
cont = msg[3:]
if not msg:
break
if ip_checksum(cont) == checksum:
sendwithcheck(s, "ACK" + seq, addr)
if seq == str(expecting_seq):
print('Message[' + addr[0] + ':' + str(addr[1]) + '] - ' + cont)
expecting_seq = 1 - expecting_seq
#reply = 'OK...' + data
#s.sendto(reply.encode('utf-8') , addr)
else:
neg_seq = str(1 - expecting_seq)
sendwithcheck(s, "ACK" + neg_seq, addr)
s.close()
# use it in this way
#https://www.bogotobogo.com/python/Multithread/python_multithreading_subclassing_Timer_Object.php
# create dgram udp socket
try:
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
except socket.error:
print 'Failed to create socket'
sys.exit()
host = 'localhost'
port = 8888
seqnum = 0 # sequence number
msg = raw_input('Enter message to send : ')
chks = str(ip_checksum(msg)) #convert checksum return value to string
data = (str(seqnum) + chks + msg)
s.sendto(data, (host, port))
while (1):
msg = raw_input('Enter message to send : ')
#chks = str(ip_checksum(msg)) #convert checksum return value to string
#data = (str(seqnum) + chks + msg) #all 3 values are strings and merged together
try:
# Set the whole string
# s.sendto(msg, (host, port))
# s.sendto(data, (host, port))
# receive data from client (data, addr)
d = s.recvfrom(1024)
PKT = 1 #packet number
N = 4 #window size
TIMEOUT = 10 #timeout time
try:
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
except socket.error:
print 'Failed to create socket'
sys.exit()
while 1:
msg = raw_input('Enter message to send : ')
# msg = msgList[count]
# old_msg = msg
# count+=1
checksum = ip_checksum(msg) #get checksum of message
# if msg[0:1] == 'C' and flag==0:
# checksum = checksum + "c"
# flag = 1
msg = str(PKT).zfill(3) + str(
checksum) + msg #new message: 00PKT+CHKSM+MSG
pkt_curr = pkt_struct(PKT,
msg) #set current: packet with packet number and msg
pkt_list.append(pkt_curr)
PKT += 1 #increment packet number
try: #try to send packet
if (pkt_curr.num < BASE + N):
pkt_curr.send_pkt(s) #s.sendto(pkt_curr.msg, (HOST, PORT))
#pkt_curr.time_sent = time.time()
inputs = [s]
old_msg = ''
resend = 0
count = 1
while(1) :
try :
while(1) :
if nextseqnum >= base + windowSize :
break
if nextseqnum > 9 :
break
msg = str(msgList[nextseqnum])
s.settimeout(3)
d = ip_checksum(msg)
msg_d = d + msg
msg_seq_d = str(nextseqnum) + msg_d
# check corrupted msg
# msg_d = 'll' + msg
if nextseqnum < base + windowSize :
print 'sending... ' + msg_seq_d
s.sendto(msg_seq_d, (host, port))
nextseqnum = nextseqnum + 1
else :
break
# receive data from client (data, addr)
try:
data = s.recvfrom(1024)
#receive data from client(data,addr)
d=s.recvfrom(1024)
data=d[0]
addr=d[1]
rc_seqnum=data[0]
get_checksum=data[1:3]
rc_msg=data[3:]
print 'Message['+addr[0]+':'+str(addr[1])+']-'+rc_msg
if ( rc_msg==''):
status=0
continue
reply_msg='OK...' +rc_msg
if ( rc_seqnum==str(expectedseqnum) and get_checksum==ip_checksum(rc_msg) ):
expectedseqnum=(expectedseqnum+1)%10
snd_seqnum=str(expectedseqnum)
snd_checksum=ip_checksum(reply_msg)
reply=rc_seqnum+snd_seqnum+snd_checksum+reply_msg
s.sendto(reply,addr)
print 'expected number is '+str(expectedseqnum)
else:
snd_seqnum=str(expectedseqnum)
snd_checksum=ip_checksum('')
if expectedseqnum==0:
ACK=9
else:
ACK=expectedseqnum-1
reply=str(ACK)+snd_seqnum+snd_checksum+''
s.sendto(reply,addr)
signal.signal(signal.SIGALRM, timer_for_ack)
signal.setitimer(signal.ITIMER_REAL, 0.01, 0.01)
winhead = 0
while not sendOver:
wincur = wintail + 1
if wincur >= winSize and winhead != wincur and wincur%winSize == winhead%winSize:
continue
data = msg_to_send()
header = int('1111111100000000', 2)
cs = pack('IH' + str(len(data)) + 's', seqno, header, data)
checksum = ip_checksum(cs)
packet = pack('I2sH' + str(len(data)) + 's', seqno, checksum, header, data)
if wincur < winSize:
winPkts.append(packet)
tickers.append(TIMEOUT)
else:
winPkts[wincur % winSize] = packet
tickers[wincur % winSize] = TIMEOUT
print "Sending P" + str(seqno) + ", timer started"
if CORRUPT > random.random():
error_data = "01234567012345678012345678012345678"
packet = pack('I2sH' + str(len(error_data)) + 's', seqno, checksum, header, error_data)
print('Socket bind complete')
expecting_seq = 0
#now keep talking with the client
while 1:
# receive data from client (data, addr)
msg, addr = s.recvfrom(1024)
#msg = msg.decode('utf-8')
checksum = msg[:2]
seq = msg[2]
cont = msg[3:]
if not msg:
break
if ip_checksum(cont) == checksum:
sendwithcheck(s, "ACK" + seq, addr)
if seq == str(expecting_seq):
print('Message[' + addr[0] + ':' + str(addr[1]) + '] - ' + cont)
expecting_seq = 1 - expecting_seq
#reply = 'OK...' + data
#s.sendto(reply.encode('utf-8') , addr)
else:
neg_seq = str(1 - expecting_seq)
sendwithcheck(s, "ACK" + neg_seq, addr)
s.close()
inputs=[s]
outputs=[]
timeout=10
while(1):
input_msg=raw_input('Enter message to send : ')
try :
status='a'
length=2
while(len(input_msg)>0):
#Set the whole string
snd_msg=input_msg[0:length]
print 'Send message : '+snd_msg
d=ip_checksum(snd_msg)
snd_status=status
send_msg=snd_status+d+snd_msg
s.sendto(send_msg,(host,port))
readable,writable,exceptional=select.select(inputs,outputs,inputs,timeout)
for s in readable:
#receive data from client (data, addr)
d=s.recvfrom(1024)
reply=d[0]
addr=d[1]
rc_status=reply[0]
get_checksum=reply[1:3]
reply_msg=reply[3:]
print 'Server reply : '+reply_msg
def makeack(s, seq, msg):
ack = seq + ip_checksum(msg) + msg
return ack
s.bind(("", PORT))
except socket.error, msg :
print 'Bind failed. Error Code: ' + str(msg[0]) + ' Message ' + msg[1]
sys.exit()
print 'Socket bind complete'
while 1:
d = s.recvfrom(1024)
data = d[0]
addr = d[1]
if not data:
break
if data[1:3] != ip_checksum(data[3:]):
continue
ACK = data[0]
reply = str(ACK) + data[3:]
s.sendto(reply, addr)
if ACK != str(PKT):
print 'DUPLICATE'
else:
PKT = 0 if PKT else 1
print 'Message[' + addr[0] + ':' + str(addr[1]) + '] - ' + data.strip()
#COUNT += 1
#if COUNT % 3 == 0:
# sleep(5)
outputs=[]
timeout=10
cwnd=4
base=0
nextseqnum=0
while(1):
input_msg=raw_input('Enter message to send : ')
try :
length=2
begin=0
end=2
while(len(input_msg[0:]) <base or len(input_msg[begin:])>0 ):
while(len(input_msg[begin:])>0 and nextseqnum<base+cwnd):
snd_msg=input_msg[begin:end]
d=ip_checksum(snd_msg)
snd_seqnum=str(nextseqnum % 10)
send_msg=snd_seqnum+d+snd_msg
s.sendto(send_msg,(host,port))
print 'Send message : '+snd_msg+', sndseqnum :' +snd_seqnum
nextseqnum=nextseqnum+1
print 'nextseqnum is '+str(nextseqnum)+', base+cwnd is '+str(base+cwnd)
sleep(1)
begin=nextseqnum*length
if(len(input_msg[nextseqnum*length:])<length):
end=begin+len(input_msg[nextseqnum*length:])
else:
end=(nextseqnum+1)*length
print 'Socket bind complete'
inputs = [s]
outputs = []
#ackstatus to return the package 0/1 if received
currAck = 0
testCase = 0
#now keep talking with the client
while 1:
d = s.recvfrom(1024)
data = d[0]
addr = d[1]
#set the checksum from from the data recieved
checksum = ip_checksum(data[1:-2])
if not data:
break
#Wrong ACK
if (data[0] != str(currAck)):
print 'Duplicate Packet'
continue
#Corrupted checksum
if (data != (str(currAck) + data[1:-2] + checksum)) and (
data != (str(not ACKstatus) + data[1:-2] + checkSum)):
print 'Corrupt'
continue
#check the test, set a timeout
if testCase == 1:
PKT = 1 #packet number
N = 4 #window size
TIMEOUT = 10 #timeout time
try:
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
except socket.error:
print 'Failed to create socket'
sys.exit()
while 1:
msg = raw_input('Enter message to send : jk hardcoded so it doesnt matter ')
msg = msgList[count]
old_msg = msg
count+=1
checksum = ip_checksum(msg) #get checksum of message
if msg[0:1] == 'C' and flag==0:
checksum = checksum + "X"
flag = 1
msg = str(PKT).zfill(3) + str(checksum) + msg #new message: 00PKT+CHKSM+MSG
pkt_curr = pkt_struct(PKT, msg) #set current: packet with packet number and msg
pkt_list.append(pkt_curr)
PKT += 1 #increment packet number
try: #try to send packet
if (pkt_curr.num < BASE + N):
pkt_curr.send_pkt(s) #s.sendto(msg, (HOST, PORT)) #gotta send the corrupted msg (not original)
#pkt_curr.time_sent = time.time()
inputs = [s]
outputs = []
while 1:
msg = raw_input("Press anykey to send packets")
try:
reset()
for i in range(2):
if base == nextseqnum:
timerStart(base, windowsize)
while 1:
d = s.recvfrom(1024)
reply = d[0]
ACK = int(reply[0])
ACKCheckSum = reply[1:]
CheckSum = ip_checksum(str(ACK))
if ACKCheckSum == CheckSum:
base = ACK + 1
if base == nextseqnum:
timer.cancel()
break
else:
timer.cancel()
timer = threading.Timer(2, timerStart,
[base, windowsize])
timer.start()
except socket.error, msg:
print 'Error code: ' + str(msg[0]) + 'Message ' + msg[1]
sys.exit()
inputs = [s] #socket
outputs = []
timeout = 0 #when timeout is 0, it basically polls
readable, writeable, expectional = select.select(inputs, outputs, inputs, timeout)
for temp_socket in readable:
received_data = temp_socket.recvfrom(1024)
received_packet = received_data[0]
address = received_data[1]
print 'Received packet: ', received_packet
packet_sequence_number, packet_data, packet_checksum = extract_data(received_packet)
#print packet_sequence_number, packet_data, packet_checksum
#check if packet has sequence number 1 or 0
#if 1 then we send an ACK1 back because there was a packet loss and
#the sender requires this ACK to make progress. Otherwise, the sender is 'stuck'
if packet_sequence_number == '1':
checksum = ip_checksum ('ACK1')
packet_to_send = make_packet ('1', 'ACK1', checksum)
#send packet
s.sendto(str(packet_to_send), address)
elif packet_sequence_number == '0' and checksum_cmp(packet_data, packet_checksum):
# we have already extracted the data
'''
This is were we would forward the data up the internet protocl stack to
the application layer or any intermediate agent between the transport and
application layer.
'''
#send ACK0 to sender
checksum = ip_checksum ('ACK0')
packet_to_send = make_packet('0', 'ACK0', checksum)
#send packet
s.sendto(str(packet_to_send), address)
#initialize thread list of size 4
threadList = [None] * windowSize
#initialize ack list of size 8
ackList = [error] * maxSeqNum
for i in range(base, base + windowSize):
timerStart(nextSeqNum, threadList, i)
nextSeqNum = nextSeqNum + 1
while 1:
d = s.recvfrom(1024)
reply = d[0]
ackNum = int(reply[0])
ackChksum = reply[1:]
chksum = ip_checksum(str(ackNum))
#check if ACK is corrupt
if ackChksum == chksum:
ackList[ackNum] = ackNum
#ACK received correctly so cancel timer
index = ackNum % 4
threadList[index].cancel()
print 'ACK ' + str(ackNum) + ' received'
if base == maxSeqNum - 1:
break
#check if next packet sent is in sender window
#base + windowSize is packet number
s.bind(("", PORT))
except socket.error, msg :
print 'Bind failed. Error Code: ' + str(msg[0]) + ' Message ' + msg[1]
sys.exit()
print 'Socket bind complete'
while 1:
d = s.recvfrom(1024)
data = d[0]
addr = d[1]
if not data:
break
if data[3:5] != ip_checksum(data[5:]):
continue
RCVPKT = int(data[0:3])
ACK = RCVPKT
#if not the packet we are waiting for re-ack previous packet
if RCVPKT != PKT: #not the right packet, send ACK of older packet
ACK = PKT - 1 #resend the previous PKT
print 'UNEXPECTED RCVPKT'
#packet we are waiting for, send next pkt
else:
PKT += 1
reply = str(ACK).zfill(3) + data[3:]
s.sendto(reply, addr)
print 'Message[' + addr[0] + ':' + str(addr[1]) + '] - ' + data.strip()
while 1:
msg = raw_input('press enter to send')
try:
reset()
thelist = [None] * 10000
acklist = [NACK] * maxseqnum
for i in range(base, base + windowsize):
timerStart(nextseqnum, thelist, i)
nextseqnum = nextseqnum + 1
while 1:
d = s.recvfrom(1024)
reply = d[0]
Num = int(reply[0])
check = (reply[1:])
CheckSum = ip_checksum(str(Num))
print 'received ack' + str(Num)
if CheckSum == check:
acklist[Num] = Num
index = Num
thelist[index].cancel()
if base == maxseqnum - 1:
break
if base == Num and nextseqnum < maxseqnum:
index = nextseqnum
timerStart(nextseqnum, thelist, index)
nextseqnum = nextseqnum + 1
base = getbase(acklist, base, windowsize)
else:
old_msg = ''
resend = 0
count =0
while(1) :
if base == 10 :
break
elif nextseqnum < base + windowSize :
msg = str(pktList[nextseqnum])
try :
s.settimeout(3)
if msg == '2' :
if count == 0:
d = ip_checksum(msg+'1')
msg_d = d + msg
msg_seq_d = str(nextseqnum) + msg_d
count = count + 1
else:
d = ip_checksum(msg)
msg_d = d + msg
msg_seq_d = str(nextseqnum) + msg_d
else :
d = ip_checksum(msg)
msg_d = d + msg
msg_seq_d = str(nextseqnum) + msg_d
if nextseqnum < base + windowSize :
print 'sending... PKT' + msg_seq_d[3:]
s.sendto(msg_seq_d, (host, port))
def makepckt(msg):
global seq_num
pckt = seq_num + ip_checksum(msg) + msg
return pckt
#now keep talking with the client
while 1:
inputs = [s]
outputs = []
timeout = 5
readable,writable,exceptional = select.select(inputs,outputs,inputs,timeout)
for tempSocket in readable:
temp = tempSocket.recvfrom(1024)
reply = temp[0]
addr = temp[1]
ack = reply[0:1]
msg_sum = reply[1:2]
msg = reply[3:len(reply)]
msg_chksum = ip_checksum(msg)
if msg_sum == msg_chksum:
message = 'received ack ' + reply[0:1]
s.sendto(message, (HOST, PORT))
else :
print 'packet corrupted'
#s.sendto(reply , addr)
s.close()
# print "Resending msg " + str(msg0[0]) + ": " + str(msg0[1:-2])
# print "Resending msg " + str(msg1[0]) + ": " + str(msg1[1:-2])
# print "Resending msg " + str(msg2[0]) + ": " + str(msg2[1:-2])
# print "Resending msg " + str(msg3[0]) + ": " + str(msg3[1:-2])
# x = threading.Thread(target = recv_thread, args=(base,))
# x.start()
# x.join(TIMEOUT)
# index = index + 4
# nextseqnum = index % (N * 2 + 1)
# base = base +1
msg = str(nextseqnum) + messages[index] + str(
ip_checksum(messages[index]))
s.sendto(msg, (host, port))
print "Sending msg " + str(msg[0]) + ": " + str(msg[1:-2])
x = threading.Thread(target=recv_thread, args=(base, ))
x.start()
x.join(TIMEOUT)
while x.isAlive():
for r in range(base, base + 3):
msg = str(r % (N * 2 + 1)) + messages[r] + str(
ip_checksum(messages[r]))
s.sendto(msg, (host, port))
print "Sending msg " + str(msg[0]) + ": " + str(msg[1:-2])
x = threading.Thread(target=recv_thread, args=(base, ))
def user_handler(name, connection):
user = user_id(name)
send_offline_tweets(name)
while True:
#connection, address = recv_sock.accept()
message = connection.recv(4096)
print '\tclient request: ' + name + ' ' + message[2:]
if not message:
break
elif message[:2] == ip_checksum(message[2:]):
if message[2:] == 'Offline_messages_request':
user = user_id(name)
if len(MsgList[user]) == 0:
msg = json.dumps({"msglist" :'No Messages Received'})
else:
msg = json.dumps({"msglist" :MsgList[user]})
connection.sendall(msg)
elif message[2:] == 'Send Message':
message = connection.recv(4096)
hdr = message[:2]
if len(connections[user_id(hdr)]) == 0:
MsgList[user_id(hdr)].append(message[2:])
else:
connections[user_id(hdr)][1].sendall('live_msg' + message[2:])
connection.sendall('success')
elif message[2:] == 'Post Tweet':
tweet = connection.recv(4096)
tweetList.append(tweet)
for j in range(0, len(connections)):
st = 'c' + str(j)
if st in subList[user_id(name)]:
if len(connections[j]) == 0:
off_list_tweets[j].append(tweet)
else:
connections[j][1].sendall('live_twt'+tweet)
elif message[2:] == 'Del_Friend_Msgs':
message = connection.recv(4096)
temp = []
temp = message.split(':')
user = temp[0]
friend = temp[1]
a = user_id(name)
lst = MsgList[a]
for l in lst:
if l[:2] == friend:
MsgList[a].remove(l)
connection.sendall('success')
elif message[2:] == 'Del_All_Msgs':
a = user_id(name)
lst = MsgList[a]
for l in lst:
MsgList[a].remove(l)
connection.sendall('success')
elif message[2:] == 'Subscribe':
msg = connection.recv(4096)
friend = msg[2:]
me = msg[:2]
subList[user_id(friend)].append(me)
connection.sendall('success')
elif message[2:] == 'Unsubscribe':
unsub = []
for i in range(0, len(subList)):
if name in subList[i]:
unsub.append('c'+str(i))
if len(unsub) == 0:
msg = json.dumps({"list" : 'No followers'})
connection.sendall(msg)
else:
msg = json.dumps({"list" : unsub})
connection.sendall(msg)
msg = connection.recv(4096)
friend = msg[2:]
me = msg[:2]
subList[user_id(friend)].remove(me)
connection.sendall('success')
elif message[2:] == 'See Followers':
if len(subList[user_id(name)]) == 0:
msg = json.dumps({"subList" : 'No Followers'})
else:
msg = json.dumps({"subList" : subList[user_id(name)]})
connection.sendall(msg)
elif message[2:] == 'Hashtag Search':
msg = connection.recv(4096)
hashList = []
for i in range(0, len(tweetList)):
if msg in tweetList[i]:
hashList.append(tweetList[i])
if len(hashList) == 0:
msg = json.dumps({"hashList" : 'No Tweets Found'})
else:
msg = json.dumps({"hashList" : hashList})
connection.sendall(msg)
elif message[2:] == 'Logging Out':
connection.sendall('success')
connection.close()
for c in connections[user_id(name)]:
connections[user_id(name)].remove(c)
return
return
def udt_send(self, flag):
checksum = ip_checksum(self.data)
sndpkt = self.make_pkt(flag, checksum)
self.s.sendto(sndpkt, (self.host, self.destport))
print('Resending timed-out packet ' + str(n) + '\n')
s.sendto(msg, (host, port))
timer = threading.Timer(3.0, pkt_timer)
# Create dgram udp socket
# Client is sender
# Packet # counter
n = 0
# Set up initial packet
# Scenario 1: Packets 0-2
print('\nSending 3 packets normally:\n')
msg = 'packet ' + str(n)
check_sum = ip_checksum(msg)
msg += ';' + str(ord(check_sum[0]) + ord(check_sum[1]))
s.sendto(msg, (host, port))
while(n < 9):
# msg = raw_input('Enter message to send: ')
# print('check_sum ' + str(ord(check_sum[0])) + '; pt 2: ' + str(ord(check_sum[1])))
try:
if n == 6:
timer.start()
# Receive data from client (data, addr)
d = s.recvfrom(1024)
reply = d[0]
addr = d[1]
timeout_test = True
# now keep talking with the client
while 1:
# receive data from client (data, addr)
data, addr = s.recvfrom(1024)
checksum = data[:2]
seq = data[2]
pkt = data[3:]
if not data:
break
# print(str(ip_checksum(pkt) == checksum))
if ip_checksum(pkt) == checksum and seq == str(expect_seq):
print('recv: Good Data Sending ACK' + str(seq))
print('recv pkt: ' + str(pkt))
# Test timeout on message 4
if str(pkt) == 'Message 4':
time.sleep(5)
s.sendto(str(seq), addr)
expect_seq = 1 - expect_seq
else:
# Check seq and send according ACK
if seq == str(expect_seq):
print('recv: Bad Checksum Not Sending')
else:
print('recv: Bad Seq Sending ACK' + str(1 - expect_seq))
s.sendto(str(1 - expect_seq), addr)
s.close()
print "Failed to create client socket"
sys.exit()
host = 'localhost'
port = 8888
i = 0
s.settimeout(2)
while(1):
flag2 = True
flag = True
msg = raw_input('Enter message to send: ')
ackNum = 999
while flag2:
try :
d = ip_checksum(msg)
if i % 2 == 0:
ackNum = 0
if flag:
tmp = str(ackNum) + "," + str(msg) + "," + "-1"
else:
tmp = str(ackNum) + "," + str(msg) + "," + d
elif i % 2 == 1:
ackNum = 1
if flag:
tmp = str(ackNum) + "," + str(msg) + "," + "-1"
else:
tmp = str(ackNum) + "," + str(msg) + "," + d
sendMessage(tmp, host, port, s)
s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
print "Socket created"
except socket.error:
print "Failed to create client socket"
sys.exit()
try:
s.bind((HOST, PORT))
print "Bind socket Created"
except socket.error, msg:
print "Failed to bind"
sys.exit()
#temp variable to save the last ack sent
tmpAck = -1
while 1:
d = s.recvfrom(1024)
data = d[0]
addr = d[1]
x = data.split(",")
if x[2] != ip_checksum(x[1]):
print "Packet was lost"
reply = str(tmpAck)
else:
if x[0] == "0" or x[0] == "1":
reply = str(x[0])
tmpAck = x[0]
s.sendto(reply, addr)
break
# Split input into data and checksum
#print('data = ' + str(data))
data = data.split(';', 1)
#print('data[1] = ' + data[1])
checksum_exp = int(data[1])
data = data[0]
print('Message[' + addr[0] + ':' + str(addr[1]) + '] - ' + data.strip())
#print('checksum_exp = ' + str(checksum_exp))
#print('checksum_exp type = ' + str(type(checksum_exp)))
#print('data = ' + data)
checksum_actual = ip_checksum(data)
checksum_actual = ord(checksum_actual[0]) + ord(checksum_actual[1])
#print('checksum_actual = ' + str(checksum_actual))
#print('checksum_actual type = ' + str(type(checksum_actual)))
if not corrupted_sent and data == 'packet 4':
checksum_actual += 1
corrupted_sent = True
if checksum_exp != checksum_actual:
reply = 'CORRUPTED: ' + data
print(reply)
print('\tchecksum_exp = ' + str(checksum_exp))
print('\tchecksum_actual = ' + str(checksum_actual))
else:
sys.exit()
# Bind socket to local host and port
try:
s.bind((HOST, PORT))
except socket.error, msg:
print 'Bind failed. Error Code : ' + str(msg[0]) + ' Message ' + msg[1]
sys.exit()
print 'Socket bind complete'
# Variables
ExpectedSeqNum = 0
N = 4
msg = "ACK" + str(ExpectedSeqNum)
check = ip_checksum(msg)
packet = str(ExpectedSeqNum) + str(len(msg)) + msg + check
rcvpkts = []
base = 0
#now keep talking with the client
while 1:
# receive data from client (data, addr)
d = s.recvfrom(1024)
packet = d[0]
SeqNum = int(packet[0])
datalength = int(packet[1])
data = packet[2:datalength + 2]
check = packet[datalength + 2:]
addr = d[1]
print 'Failed to create socket. Error Code : ' + str(
msg[0]) + ' Message ' + msg[1]
sys.exit()
# Bind socket to local host and port
try:
s.bind((HOST, PORT))
except socket.error, msg:
print 'Bind failed. Error Code : ' + str(msg[0]) + ' Message ' + msg[1]
sys.exit()
print 'Socket bind complete'
ExpectedSeqNum = 0
msg = "ACK" + str(ExpectedSeqNum)
check = ip_checksum(msg)
packet = str(ExpectedSeqNum) + str(len(msg)) + msg + check
#now keep talking with the client
while 1:
# receive data from client (data, addr)
d = s.recvfrom(1024)
packet = d[0]
SeqNum = int(packet[0])
datalength = int(packet[1])
data = packet[2:datalength + 2]
check = packet[datalength + 2:]
addr = d[1]
if not data:
break
print 'Timed Out: Retry sending Packet' + str(SeqNum)
msg = 'Hello ' + str(SeqNum)
check = ip_checksum(msg)
packet = str(SeqNum) + str(len(msg)) + msg + check
s.sendto(packet, (host, port))
Corrupt = raw_input("Do you want there to be a corrupt packet?(Y or N)")
while (1):
progress = raw_input("Press Enter to send more packets")
for i in range(0, j):
t = threading.Timer(2.0, Timeout)
msg = 'Hello ' + str(SeqNum)
if i == 1 and Corrupt == 'Y':
check = str(1) + ip_checksum(msg)
else:
check = ip_checksum(msg)
packet = str(SeqNum) + str(len(msg)) + msg + check
try:
#Send the whole string
t.start()
s.sendto(packet, (host, port))
d = s.recvfrom(1024)
packet = d[0]
AckNum = int(packet[0])
replylength = int(packet[1])
reply = packet[2:replylength + 2]
check = packet[replylength + 2:]
addr = d[1]
print 'Bind failed. Error Code : ' + str(msg[0]) + ' Message ' + msg[1]
sys.exit()
print 'Socket bind complete'
seq_num = '100' # bogus initial value
while 1:
d = s.recvfrom(1024)
data = d[0]
addr = d[1]
if not data:
break
prev_sn = seq_num
seq_num = data[0]
if data[-2:] != ip_checksum(data[1:-2]):
print 'Packet corrupted'
else:
reply = 'ACK' + str(seq_num)
# Add for scenario 3: time.sleep(8)
s.sendto(reply, addr)
if seq_num != prev_sn:
print 'Message[' + addr[0] + ':' + str(
addr[1]) + '] - ' + data.strip()[1:-2]
else:
print 'Duplicate detected'
s.close()
def Timeout():
print 'Timed Out: Retry sending Packet' + str(SeqNum)
msg = 'Hello ' + str(SeqNum)
check = ip_checksum(msg)
packet = str(SeqNum) + str(len(msg)) + msg + check
s.sendto(packet, (host, port))
print 'Bind failed. Error Code : ' + str(msg[0]) + ' Message ' + msg[1]
sys.exit()
print 'Socket bind complete'
#states for GBN receiver
states = ['wait']
states_list = list(enumerate(states))
current_state = states_list[0]
delay_ack1 = 0
#packet1_corrput = 0
expected_seq_num = 0
msg = 'ACK' + str (expected_seq_num)
checksum = ip_checksum(msg)
#create packet
packet_to_send = make_packet(str(expected_seq_num), msg, checksum)
#related variables for select
inputs = [s] #socket
outputs = []
timeout = 0 #when timeout is 0, it basically polls
readable = []
writeable = []
expectional =[]
#now keep talking with the client
while 1:
if current_state == states_list[0]:
readable, writeable, expectional = select.select(inputs, outputs, inputs, timeout)
while(1) :
seq = 0
try :
while True:
msg = raw_input('Enter message to send(Q for quit): ')
if msg == 'Q' or msg == 'q':
sys.exit()
ack_received = False
while not ack_received:
#Set the whole string
tosend = ip_checksum(msg) + str(seq) + msg
rand = random.randint(1, 20)
if rand >= 1 and rand <= 5:
print("Corrupted")
tosend = corrupt(tosend)
s.sendto(tosend, (host, port))
# receive data from client (data, addr)
try:
reply, addr = s.recvfrom(1024)
except socket.timeout:
print('Timeout')
else:
