def getTCPPacket(self):
"""
构造TCP数据包
:return:
"""
try:
ip_packet = IP()
ip_packet.version = int(self.entries[8].get())
ip_packet.ihl = int(self.entries[9].get())
ip_packet.tos = int(self.entries[10].get())
ip_packet.id = int(self.entries[11].get())
# ip_packet.flags = int(self.entries[12].get())
ip_packet.frag = int(self.entries[13].get())
ip_packet.ttl = int(self.entries[14].get())
# ip_packet.chksum = self.entries[15].get()
ip_packet.src = self.entries[16].get()
ip_packet.dst = self.entries[17].get()
tcp_packet = TCP()
tcp_packet.sport = int(self.entries[0].get())
tcp_packet.dport = int(self.entries[1].get())
tcp_packet.seq = int(self.entries[2].get())
tcp_packet.ack = int(self.entries[3].get())
tcp_packet.dataofs = int(self.entries[4].get())
tcp_packet.flags = int(self.entries[5].get())
tcp_packet.window = int(self.entries[6].get())
# tcp_packet.chksum = self.entries[7].get()
# scapy自动计算IP、TCP校验和
# 获得数据包的二进制值
pkg_raw = raw(ip_packet / tcp_packet)
tcp_packet_raw = pkg_raw[20:]
# 构造数据包，自动计算校验和
scapy_chksum_IP = IP(pkg_raw).chksum
scapy_chksum_tcp = TCP(tcp_packet_raw).chksum
print("scapy自动计算的TCP校验和为：%04x" % scapy_chksum_tcp)
# 手动计算TCP校验和
tcp_packet.chksum = 0
packet = ip_packet / tcp_packet
tcp_raw = raw(packet)[20:]
self_chksum = in4_chksum(socket.IPPROTO_TCP, packet[IP], tcp_raw)
print("手动计算的TCP校验和为：%04x" % self_chksum)
if self_chksum == scapy_chksum_tcp:
print("TCP验证和正确")
else:
print("TCP验证和不正确")
tcp_packet.chksum = scapy_chksum_tcp
self.entries[7].delete(0, END)
self.entries[7].insert(0, hex(scapy_chksum_tcp))
self.entries[15].delete(0, END)
self.entries[15].insert(0, hex(scapy_chksum_IP))
tcp_packet.show()
self.resultText.insert('end', tcp_packet.summary() + '\n')
self.resultText.insert('end', str(tcp_packet) + '\n')
return Ether() / ip_packet / tcp_packet
except Exception as e:
print(e.with_traceback())
finally:
pass
def fsend(self, payload, seq=None, ack=None, tcp=None, flags=None):
"""
fsend(payload, seq=None, ack=None, tcp=None, flags=None)
send a packet without be connected
NOTE: will break the seq and ack numbers if you're currently connected
:param payload: payload to be sent
:param seq: specify new seq number
:param ack: specify new ack number
:param tcp: specify tcp segment of the packet
:param flags: specify tcp flags
"""
ip = IP(src=self.src, dst=self.dst)
tcp = tcp
if tcp is None:
tcp = TCP(sport=self.sport, dport=self.dport)
tcp.seq = seq
tcp.ack = ack
tcp.flags = flags
send(ip / tcp / payload)