我因 python TCP 打孔而被拒绝连接

Posted 2023-04-15

【中文标题】我因 python TCP 打孔而被拒绝连接

【英文标题】：I got connection refused for python TCP HolePunching

【发布时间】：2021-02-24 12:37:50

【问题描述】：

这是服务器端的代码：

#!/usr/bin/env python
import sys
import logging
import socket
import struct
import fcntl
import os
from util import *


logger = logging.getLogger()
clients = 


def main(host='**client public ip**', port=3443):
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    s.bind((host, port))
    s.listen(1)
    s.settimeout(30)

    while True:
        try:
            conn, addr = s.accept()
        except socket.timeout:
            continue

        logger.info('connection address: %s', addr)
        data = recv_msg(conn)
        priv_addr = msg_to_addr(data)
        send_msg(conn, addr_to_msg(addr))
        data = recv_msg(conn)
        data_addr = msg_to_addr(data)
        if data_addr == addr:
            logger.info('client reply matches')
            clients[addr] = Client(conn, addr, priv_addr)
        else:
            logger.info('client reply did not match')
            conn.close()

        logger.info('server - received data: %s', data)

        if len(clients) == 2:
            (addr1, c1), (addr2, c2) = clients.items()
            logger.info('server - send client info to: %s', c1.pub)
            send_msg(c1.conn, c2.peer_msg())
            logger.info('server - send client info to: %s', c2.pub)
            send_msg(c2.conn, c1.peer_msg())
            clients.pop(addr1)
            clients.pop(addr2)

    conn.close()


if __name__ == '__main__':
    logging.basicConfig(level=logging.INFO, format='%(asctime)s - %(message)s')
    main(*addr_from_args(sys.argv))

这是客户端：

#!/usr/bin/env python
import sys
import logging
import socket
import struct
from threading import Event, Thread
from util import *


logger = logging.getLogger('client')
logging.basicConfig(level=logging.INFO, format='%(asctime)s - %(message)s')
STOP = Event()


def accept(port):
    logger.info("accept %s", port)
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
    s.bind(('**server's public ip**', port))
    s.listen(1)
    s.settimeout(5)
    while not STOP.is_set():
        try:
            conn, addr = s.accept()
        except socket.timeout:
            continue
        else:
            logger.info("Accept %s connected!", port)
            # STOP.set()


def connect(local_addr, addr):
    logger.info("connect from %s to %s", local_addr, addr)
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
    s.bind(local_addr)
    while not STOP.is_set():
        try:
            s.connect(addr)
        except socket.error:
            continue
        # except Exception as exc:
        #     logger.exception("unexpected exception encountered")
        #     break
        else:
            logger.info("connected from %s to %s success!", local_addr, addr)
            # STOP.set()


def main(host='**client's local ip**', port=3443):
    sa = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    sa.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    sa.connect((host, port))
    priv_addr = sa.getsockname()

    send_msg(sa, addr_to_msg(priv_addr))
    data = recv_msg(sa)
    logger.info("client %s %s - received data: %s", priv_addr[0], priv_addr[1], data)
    pub_addr = msg_to_addr(data)
    send_msg(sa, addr_to_msg(pub_addr))

    data = recv_msg(sa)
    pubdata, privdata = data.split(b'|')
    client_pub_addr = msg_to_addr(pubdata)
    client_priv_addr = msg_to_addr(privdata)
    logger.info(
        "client public is %s and private is %s, peer public is %s private is %s",
        pub_addr, priv_addr, client_pub_addr, client_priv_addr,
    )

    threads = 
        '0_accept': Thread(target=accept, args=(priv_addr[1],)),
        '1_accept': Thread(target=accept, args=(client_pub_addr[1],)),
        '2_connect': Thread(target=connect, args=(priv_addr, client_pub_addr,)),
        '3_connect': Thread(target=connect, args=(priv_addr, client_priv_addr,)),
    
    for name in sorted(threads.keys()):
        logger.info('start thread %s', name)
        threads[name].start()

    while threads:
        keys = list(threads.keys())
        for name in keys:
            try:
                threads[name].join(1)
            except TimeoutError:
                continue
            if not threads[name].is_alive():
                threads.pop(name)


if __name__ == '__main__':
    logging.basicConfig(level=logging.INFO, message='%(asctime)s %(message)s')
    main(*addr_from_args(sys.argv))

这是 util.py 代码：

import struct
from collections import namedtuple

def addr_from_args(args, host='**server's local ip**', port=9999):
    if len(args) >= 3:
        host, port = args[1], int(args[2])
    elif len(args) == 2:
        host, port = host, int(args[1])
    else:
        host, port = host, port
    return host, port


def msg_to_addr(data):
    ip, port = data.decode('utf-8').strip().split(':')
    return (ip, int(port))


def addr_to_msg(addr):
    return ':'.format(addr[0], str(addr[1])).encode('utf-8')


def send_msg(sock, msg):
    # Prefix each message with a 4-byte length (network byte order)
    msg = struct.pack('>I', len(msg)) + msg
    sock.sendall(msg)


def recvall(sock, n):
    # Helper function to recv n bytes or return None if EOF is hit
    data = b''
    while len(data) < n:
        packet = sock.recv(n - len(data))
        if not packet:
            return None
        data += packet
    return data


def recv_msg(sock):
    # Read message length and unpack it into an integer
    raw_msglen = recvall(sock, 4)
    if not raw_msglen:
        return None
    msglen = struct.unpack('>I', raw_msglen)[0]
    # Read the message data
    return recvall(sock, msglen)


class Client(namedtuple('Client', 'conn, pub, priv')):

    def peer_msg(self):
        return addr_to_msg(self.pub) + b'|' + addr_to_msg(self.priv)

这是错误：

Traceback (most recent call last):
  File "tcpclient.py", line 96, in <module>
    main(*addr_from_args(sys.argv))
  File "tcpclient.py", line 55, in main
    sa.connect((host, port))
ConnectionRefusedError: [Errno 111] Connection refused

它在同一个网络中工作，但在不同的网络中不行！ 为了添加更多详细信息，我想说我们有一个客户端和一个想要相互通信的服务器，客户端和服务器都在 nat 后面，服务器有 webserver，客户端想去 webserver 但由于 nat 问题它不能。所以我们正在尝试建立一个打孔点对点连接，以使客户端能够看到网络服务器。 我们不能接受任何类型的 ip 静态或商业网络服务或 isp 或任何人所说的。 这段代码有什么问题？

【参考方案1】：

在 util.py 中 ip 应该是公开的而不是私有的

import struct
from collections import namedtuple

def addr_from_args(args, host='**server's ip public**', port=9999):
    if len(args) >= 3:
        host, port = args[1], int(args[2])
    elif len(args) == 2:
        host, port = host, int(args[1])
    else:
        host, port = host, port
    return host, port


def msg_to_addr(data):
    ip, port = data.decode('utf-8').strip().split(':')
    return (ip, int(port))


def addr_to_msg(addr):
    return ':'.format(addr[0], str(addr[1])).encode('utf-8')


def send_msg(sock, msg):
    # Prefix each message with a 4-byte length (network byte order)
    msg = struct.pack('>I', len(msg)) + msg
    sock.sendall(msg)


def recvall(sock, n):
    # Helper function to recv n bytes or return None if EOF is hit
    data = b''
    while len(data) < n:
        packet = sock.recv(n - len(data))
        if not packet:
            return None
        data += packet
    return data


def recv_msg(sock):
    # Read message length and unpack it into an integer
    raw_msglen = recvall(sock, 4)
    if not raw_msglen:
        return None
    msglen = struct.unpack('>I', raw_msglen)[0]
    # Read the message data
    return recvall(sock, msglen)


class Client(namedtuple('Client', 'conn, pub, priv')):

    def peer_msg(self):
        return addr_to_msg(self.pub) + b'|' + addr_to_msg(self.priv)