network.py 文件源码

def make_header(self, source_ip, destination_ip, data_len, transport_protocol_len, transport_protocol, ttl=64):
        srcip = inet_aton(source_ip)       # Source port
        dstip = inet_aton(destination_ip)  # Destination port
        ver = 4       # IP protocol version
        ihl = 5       # Internet Header Length
        dscp_ecn = 0  # Differentiated Services Code Point and Explicit Congestion Notification

        tlen = data_len + transport_protocol_len + 20  # Packet length
        ident = htons(randint(1, 65535))  # Identification
        flg_frgoff = 0  # Flags and fragmentation offset
        ptcl = transport_protocol  # Protocol
        chksm = 0  # Checksum

        ip_header = pack("!" "2B" "3H" "2B" "H" "4s" "4s",
                         (ver << 4) + ihl, dscp_ecn, tlen, ident,
                         flg_frgoff, ttl, ptcl, chksm, srcip, dstip)
        chksm = self.checksum(ip_header)
        return pack("!" "2B" "3H" "2B" "H" "4s" "4s",
                    (ver << 4) + ihl, dscp_ecn, tlen, ident,
                    flg_frgoff, ttl, ptcl, chksm, srcip, dstip)