Python implements methods for port transponders

This article illustrates how python implements port transponders. Share with you for your reference. The details are as follows:

The following python code implements a port repeater that supports udp port forwarding

Because the work requires a port transponder and requires support for TCP and UDP protocols. I searched the Internet for a long time, but nothing interested me. So he wrote one for himself. The repeater is based on an example from the python cookbook that only supports TCP. I've added support for UDP, which isn't very well written, but it works!

The portmap.py code is as follows:

#-* -coding: UTF-8 -* -

'''

Created on 2012-5-8

@author: qh

'''

import time,socket,threading

def log(strLog):

    strs=time.strftime("%Y-%m-%d %H:%M:%S")

    print strs+"->"+strLog

class pipethread(threading.Thread):

    '''

    classdocs

    '''

    def __init__(self,source,sink):

        '''

        Constructor

        '''

        threading.Thread.__init__(self)

        self.source=source

        self.sink=sink

        log("New Pipe create:%s->%s" % (self.source.getpeername(),self.sink.getpeername()))

    def run(self):

        while True:

            try:

                data=self.source.recv(1024)

                if not data: break

                self.sink.send(data)

            except Exception ,ex:

                log("redirect error:"+str(ex))

                break

        self.source.close()

        self.sink.close()

class portmap(threading.Thread):

    def __init__(self,port,newhost,newport,local_ip=''):

        threading.Thread.__init__(self)

        self.newhost=newhost

        self.newport=newport

        self.port=port

        self.local_ip=local_ip

        self.sock=None

        self.sock=socket.socket(socket.AF_INET,socket.SOCK_STREAM)

        self.sock.bind((self.local_ip,port))

        self.sock.listen(5)

        log("start listen protocol:%s,port:%d " % ('tcp',port))

    def run(self):

        while True:

            fwd=None

            newsock=None

            newsock,address=self.sock.accept()

            log("new connection->protocol:%s,local port:%d,remote address:%s" % ('tcp',self.port,address[0]))

            fwd=socket.socket(socket.AF_INET,socket.SOCK_STREAM)

            try:

                fwd.connect((self.newhost,self.newport))

            except Exception ,ex:

                log("connet newhost error:"+str(ex))

                break

            p1=pipethread(newsock,fwd,self.protocol)

            p1.start()

            p2=pipethread(fwd,newsock,self.protocol)

            p2.start()

class pipethreadUDP(threading.Thread):

    def __init__(self,connection,connectionTable,table_lock):

        threading.Thread.__init__(self)

        self.connection=connection

        self.connectionTable=connectionTable

        self.table_lock=table_lock

        log('new thread for new connction')

    def run(self):

        while True:

            try:

                data,addr=self.connection['socket'].recvfrom(4096)

                #log('recv from addr"%s' % str(addr))

            except Exception ,ex:

                log("recvfrom error:"+str(ex))

                break

            try:

                self.connection['lock'].acquire()

                self.connection['Serversocket'].sendto(data,self.connection['address'])

                #log('sendto address:%s' % str(self.connection['address']))

            except Exception ,ex:

                log("sendto error:"+str(ex))

                break

            finally:self.connection['lock'].release()

            self.connection['time']=time.time()

        self.connection['socket'].close()

        log("thread exit for: %s" % str(self.connection['address']))

        self.table_lock.acquire()

        self.connectionTable.pop(self.connection['address'])

        self.table_lock.release()

        log('Release udp connection for timeout:%s' % str(self.connection['address']))

class portmapUDP(threading.Thread):

    def __init__(self,port,newhost,newport,local_ip=''):

        threading.Thread.__init__(self)

        self.newhost=newhost

        self.newport=newport

        self.port=port

        self.local_ip=local_ip

        self.sock=socket.socket(socket.AF_INET,socket.SOCK_DGRAM)

        self.sock.bind((self.local_ip,port))

        self.connetcTable={}

        self.port_lock=threading.Lock()

        self.table_lock=threading.Lock()

        self.timeout=300

        #ScanUDP(self.connetcTable,self.table_lock).start()

        log('udp port redirect run->local_ip:%s,local_port:%d,remote_ip:%s,remote_port:%d' % (local_ip,port,newhost,newport))

    def run(self):

        while True:

            data,addr=self.sock.recvfrom(4096)

            connection=None

            newsock=None

            self.table_lock.acquire()

            connection=self.connetcTable.get(addr)

            newconn=False

            if connection is None:

                connection={}

                connection['address']=addr

                newsock=socket.socket(socket.AF_INET,socket.SOCK_DGRAM)

                newsock.settimeout(self.timeout)

                connection['socket']=newsock

                connection['lock']=self.port_lock

                connection['Serversocket']=self.sock

                connection['time']=time.time()

                newconn=True

                log('new connection:%s' % str(addr))

            self.table_lock.release()

            try:

                connection['socket'].sendto(data,(self.newhost,self.newport))

            except Exception ,ex:

                log("sendto error:"+str(ex))

                #break

            if newconn:

                self.connetcTable[addr]=connection

                t1=pipethreadUDP(connection,self.connetcTable,self.table_lock)

                t1.start()

        log('main thread exit')

        for key in self.connetcTable.keys():

            self.connetcTable[key]['socket'].close()

if __name__=='__main__':

    myp=portmapUDP(10061,'10.0.1.29',161)

    myp.start()

    #myp.__stop()

I hope this article has helped you with your Python programming.