UDP part TODO and TCP header length edit

raw_python/lib/Tcp.py

@@ -154,7 +154,7 @@ def create_tcp_feilds(self):
         self.tcp_ack_seq = self.ack
 
         # ---- [ Header Length ]
-        self.tcp_hdr_len = 80
+        self.tcp_hdr_len = 20
 
         # ---- [ TCP Flags ]
         f = self.flags
@@ -184,3 +184,4 @@ def create_tcp_feilds(self):
         self.tcp_urg_ptr = 0
 
         return
+

raw_python/lib/Udp.py

@@ -34,3 +34,109 @@
 
 
 # TODO: complete this
+
+import socket
+import struct
+
+from ..samples import utils
+
+UDP_STRUCTURE_FMT = '!HHHH'
+
+class UDPPacket:
+    def __init__(self,
+                 dport=80,
+                 sport=65535,
+                 dst='127.0.0.1',
+                 src=utils.get_ip(),  # '192.168.1.101',
+                 data=''
+                 ):
+        self.dport = dport
+        self.sport = sport
+        self.src_ip = src
+        self.dst_ip = dst
+        self.data = data
+        self.raw = None
+        self.create_udp_feilds()
+        self.assemble_udp_feilds()
+        # self.calculate_chksum()
+        # self.reassemble_udp_feilds()
+
+    def assemble_udp_feilds(self):
+        self.raw = struct.pack('!HHHH',  # Data Structure Representation
+                               self.sport,  # Source Port
+                               self.dport,  # Destination Port
+                               self.udp_len,  # Total Length
+                               self.udp_chksum,  # UDP
+                             )
+
+        self.calculate_chksum()  # Call Calculate CheckSum
+        return
+
+    def reassemble_udp_feilds(self):
+        self.raw = struct.pack(UDP_STRUCTURE_FMT,
+                               self.udp_src,
+                               self.udp_dst,
+                               self.udp_len,
+                               socket.htons(self.udp_chksum)
+                               )
+        return
+
+    def calculate_chksum(self):
+        src_addr = socket.inet_aton(self.src_ip)
+        dest_addr = socket.inet_aton(self.dst_ip)
+        placeholder = 0
+        protocol = socket.IPPROTO_UDP
+        self.udp_len = len(self.raw) + len(self.data)
+
+        psh = struct.pack('!4s4sBBH',
+                          src_addr,
+                          dest_addr,
+                          placeholder,
+                          protocol,
+                          self.udp_len
+                          )
+
+        psh = ''.join([psh, self.raw, self.data])
+
+        self.udp_chksum = self.chksum(psh)
+
+        self.reassemble_udp_feilds()
+
+        return
+
+    def chksum(self, msg):
+        s = 0  # Binary Sum
+
+        # loop taking 2 characters at a time
+        for i in range(0, len(msg), 2):
+            if (i + 1) < len(msg):
+                a = ord(msg[i])
+                b = ord(msg[i + 1])
+                s = s + (a + (b << 8))
+            elif (i + 1) == len(msg):
+                s += ord(msg[i])
+            else:
+                raise Exception("Something Wrong here")
+
+        s = (s >> 16) + (s & 0xffff)
+        # One's Complement
+        s = s + (s >> 16)
+        s = ~s & 0xffff
+
+        return s
+
+    def create_udp_feilds(self):
+
+        # ---- [ Source Port ]
+        self.udp_src = self.sport
+
+        # ---- [ Destination Port ]
+        self.udp_dst = self.dport
+
+        # ---- [ Header Length ]
+        self.udp_len = 16
+
+        # ---- [ UDP CheckSum ]
+        self.udp_chksum = 0
+
+        return

traceroute.py

@@ -0,0 +1,60 @@
+import ping
+import socket
+import time
+
+def main():
+    ttl = 1
+    tries = 3
+    arrived = False
+    ipfound = False
+
+    # create socket
+    s = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_ICMP)
+
+    # take Input
+    addr = input("Enter Domain Name : ") or "www.sustc.edu.cn"
+    print('traceroute {0} ({1})'.format(addr, socket.gethostbyname(addr)))
+    print("No. Address         rtts")
+
+
+    while not arrived:
+        s.setsockopt(socket.SOL_IP, socket.IP_TTL, ttl)
+
+        for i in range(0, tries):
+            # Request sent
+            ID = ping.single_ping_request(s, addr)
+
+            rtt, reply, icmp_reply = ping.catch_ping_reply(s, ID, time.time())
+            #print(rtt)
+
+            if reply:
+                reply['length'] = reply['Total Length'] - 20  # sub header
+
+            if i == 0:
+                print(str(ttl) , end=" ")
+
+            if reply == None:
+                print('*    ', end=" ")
+                continue
+
+            if socket.gethostbyname(addr) == reply["Source Address"]:
+                #print("arrived")
+                arrived = True
+
+            if i == 0 or ipfound == False:
+                print(str(reply["Source Address"]), end="   ")
+                ipfound = True
+
+            print(('{0:.2f} ms    '.format(rtt*1000)), end=" ")
+
+        print("")
+        ttl += 1
+        ipfound = False
+
+    # close socket
+    s.close()
+    return
+
+
+if __name__ == '__main__':
+    main()