想用原始套接字发送syn请求，出现一个问题，是因为构建的包的格式有问题吗？

Question

import random
import socket
import struct
import array

def create_socket():
    s = socket.socket(socket.AF_INET, socket.SOCK_RAW, socket.IPPROTO_TCP)
    s.setsockopt(socket.IPPROTO_IP, socket.IP_HDRINCL,1)
    return s

def get_host_ip():
    s=socket.socket(socket.AF_INET,socket.SOCK_DGRAM)
    s.connect(('8.8.8.8',80))
    ip=s.getsockname()[0]
    s.close()
    return ip

def doCksum(packet):
    words = array.array('h', packet)
    sum = 0
    for word in words:
        sum += (word & 0xffff)
    sum = (sum >> 16) + (sum & 0xffff)
    sum += (sum >> 16)
    return (~sum) & 0xffff

def create_ip_header(source_ip, dest_ip):
    # ip 头部选项
    headerlen = 5
    version = 4
    tos = 0
    tot_len = 20 + 20
    id = random.randrange(18000,65535,1)
    frag_off = 0
    ttl = 255
    protocol = socket.IPPROTO_TCP
    check = 10
    saddr = socket.inet_aton ( source_ip )
    daddr = socket.inet_aton ( dest_ip )
    hl_version = (version << 4) + headerlen
    ip_header = struct.pack('BBHHHBBH4s4s', hl_version, tos, tot_len, id, frag_off, ttl, protocol, check, saddr, daddr)

    return ip_header

def create_tcp_syn_header(source_ip, dest_ip, dest_port):
    source = random.randrange(32000,62000,1)
    seq = 0
    ack_seq = 0
    doff = 5
    fin = 0
    syn = 1
    rst = 0
    psh = 0
    ack = 0
    urg = 0
    window = socket.htons(8192)
    check = 0
    urg_ptr = 0
    offset_res = (doff << 4) + 0
    tcp_flags = fin + (syn<<1) + (rst<<2) + (psh<<3) + (ack<<4) + (urg<<5)
    tcp_header = struct.pack('HHLLBBHHH', source, dest_port, seq, ack_seq, offset_res, tcp_flags, window, check, urg_ptr)
    source_address = socket.inet_aton( source_ip )
    dest_address = socket.inet_aton( dest_ip )
    placeholder = 0
    protocol = socket.IPPROTO_TCP
    tcp_length = len(tcp_header)
    psh = struct.pack('4s4sBBH', source_address, dest_address, placeholder, protocol, tcp_length)
    psh = psh + tcp_header
    tcp_checksum = doCksum(psh)
    tcp_header = struct.pack('HHLLBBHHH', source, dest_port, seq, ack_seq, offset_res, tcp_flags, window, tcp_checksum, urg_ptr)
    return tcp_header

source_ip = get_host_ip()
dest_ip = '112.80.248.75'
s = create_socket()
ip_header = create_ip_header(source_ip,dest_ip)
tcp_header = create_tcp_syn_header(source_ip,dest_ip,80)
packet = ip_header + tcp_header
s.sendto(packet,(dest_ip,80))

结果

Answer 1

https://blog.csdn.net/nia305/article/details/81026637