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| 1 | +#!/usr/bin/python |
| 2 | + |
| 3 | +import socket |
| 4 | +import select |
| 5 | +import sys |
| 6 | +import os |
| 7 | + |
| 8 | +def tcpbug(listenaddr, destaddr, outputfd): |
| 9 | + listen = socket.socket(socket.AF_INET, socket.SOCK_STREAM) |
| 10 | + listen.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) |
| 11 | + listen.bind(listenaddr) |
| 12 | + listen.listen(1) |
| 13 | + |
| 14 | + client, addr = listen.accept() |
| 15 | + |
| 16 | + server = socket.socket(socket.AF_INET, socket.SOCK_STREAM) |
| 17 | + server.connect(destaddr) |
| 18 | + |
| 19 | + cwbuf = swbuf = outbuf = '' |
| 20 | + |
| 21 | + while client or server or outbuf: |
| 22 | + readset = [] |
| 23 | + if client: |
| 24 | + readset.append(client) |
| 25 | + if server: |
| 26 | + readset.append(server) |
| 27 | + |
| 28 | + writeset = [] |
| 29 | + if cwbuf and client: |
| 30 | + writeset.append(client) |
| 31 | + if swbuf and server: |
| 32 | + writeset.append(server) |
| 33 | + if outbuf: |
| 34 | + writeset.append(outputfd) |
| 35 | + |
| 36 | + readset, writeset, e = select.select(readset, writeset, []) |
| 37 | + |
| 38 | + if client in readset: |
| 39 | + data = client.recv(2000) |
| 40 | + if data: |
| 41 | + swbuf = swbuf + data |
| 42 | + outbuf = outbuf + 'C%d\n%s' % (len(data), data) |
| 43 | + else: |
| 44 | + client = None |
| 45 | + |
| 46 | + if server in readset: |
| 47 | + data = server.recv(2000) |
| 48 | + if data: |
| 49 | + cwbuf = cwbuf + data |
| 50 | + outbuf = outbuf + 'S%d\n%s' % (len(data), data) |
| 51 | + else: |
| 52 | + server = None |
| 53 | + |
| 54 | + if client in writeset: |
| 55 | + n = client.send(cwbuf) |
| 56 | + cwbuf = cwbuf[n:] |
| 57 | + |
| 58 | + if server in writeset: |
| 59 | + n = server.send(swbuf) |
| 60 | + swbuf = swbuf[n:] |
| 61 | + |
| 62 | + if outputfd in writeset: |
| 63 | + n = os.write(outputfd, outbuf) |
| 64 | + outbuf = outbuf[n:] |
| 65 | + |
| 66 | + if client and not cwbuf and not server: |
| 67 | + client.close() |
| 68 | + client = None |
| 69 | + |
| 70 | + if server and not swbuf and not client: |
| 71 | + server.close() |
| 72 | + server = None |
| 73 | + |
| 74 | +def main(): |
| 75 | + try: |
| 76 | + lport = int(sys.argv[1]) |
| 77 | + dhost = sys.argv[2] |
| 78 | + dport = int(sys.argv[3]) |
| 79 | + except (IndexError, ValueError): |
| 80 | + sys.stderr.write('Usage: %s listenport desthost destport\n' |
| 81 | + % sys.argv[0]) |
| 82 | + exit(1) |
| 83 | + |
| 84 | + tcpbug(('', lport), (dhost, dport), 1) |
| 85 | + |
| 86 | +if __name__ == '__main__': |
| 87 | + main() |
| 88 | + |
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