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#!/usr/bin/python
import socket
import select
import sys
import os
def tcpbug(listenaddr, destaddr, outputfd):
listen = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
listen.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
listen.bind(listenaddr)
listen.listen(1)
client, addr = listen.accept()
server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
server.connect(destaddr)
cwbuf = swbuf = outbuf = ''
while client or server or outbuf:
readset = []
if client:
readset.append(client)
if server:
readset.append(server)
writeset = []
if cwbuf and client:
writeset.append(client)
if swbuf and server:
writeset.append(server)
if outbuf:
writeset.append(outputfd)
readset, writeset, e = select.select(readset, writeset, [])
if client in readset:
data = client.recv(2000)
if data:
swbuf = swbuf + data
outbuf = outbuf + 'C%d\n%s' % (len(data), data)
else:
client = None
if server in readset:
data = server.recv(2000)
if data:
cwbuf = cwbuf + data
outbuf = outbuf + 'S%d\n%s' % (len(data), data)
else:
server = None
if client in writeset:
n = client.send(cwbuf)
cwbuf = cwbuf[n:]
if server in writeset:
n = server.send(swbuf)
swbuf = swbuf[n:]
if outputfd in writeset:
n = os.write(outputfd, outbuf)
outbuf = outbuf[n:]
if client and not cwbuf and not server:
client.close()
client = None
if server and not swbuf and not client:
server.close()
server = None
def main():
try:
lport = int(sys.argv[1])
dhost = sys.argv[2]
dport = int(sys.argv[3])
except (IndexError, ValueError):
sys.stderr.write('Usage: %s listenport desthost destport\n'
% sys.argv[0])
exit(1)
tcpbug(('', lport), (dhost, dport), 1)
if __name__ == '__main__':
main()
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