81 lines
2.1 KiB
Python
Executable File
81 lines
2.1 KiB
Python
Executable File
#!/usr/bin/env python3
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import sys
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import pytun
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import struct
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import ipaddress
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import json
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import socket
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class IpHeader:
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def __init__(self, raw):
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self.ver_ihl, \
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self.tos, \
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self.total_length, \
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self.ident, \
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self.flags_fragoffset, \
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self.ttl, \
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self.proto, \
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self.chksum, \
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src, \
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dst, \
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self.opt1, \
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self.opt2, \
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self.pad = struct.unpack('>BBHHHBBHIIHBB', raw)
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self.src = ipaddress.IPv4Address(src)
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self.dst = ipaddress.IPv4Address(dst)
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def main():
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config_filename = sys.argv[1]
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with open(config_filename) as config_file:
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config = json.load(config_file)
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tun_iface = pytun.TunTapDevice()
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print(tun_iface.name)
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tun_iface.addr = config['iface_addr']
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tun_iface.dstaddr = config['iface_dstaddr']
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tun_iface.netmask = config['iface_netmask']
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tun_iface.mtu = config['iface_mtu']
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tun_iface.up()
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addr_and_port = (config['address'], config['port'])
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if config['mode'] == 'client':
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conn = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
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print('connecting to %s, port %s' % addr_and_port)
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conn.connect(addr_and_port)
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print('connected!')
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elif config['mode'] == 'server':
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sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
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print('binding to %s, port %s' % addr_and_port)
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sock.bind(addr_and_port)
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sock.listen(1)
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print('waiting for incoming connection')
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conn, client_addr = sock.accept()
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print('accepted incoming connection from %s' % client_addr[0])
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else:
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raise RuntimeError('invalid mode "%s"' % config['mode'])
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while True:
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buf = tun_iface.read(tun_iface.mtu)
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flags = buf[:2]
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proto = buf[2:4]
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if proto != b'\x08\x00':
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continue
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ip_header = IpHeader(buf[4:28])
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body = buf[28:]
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print(ip_header.src, '→', ip_header.dst, 'len: %d' % ip_header.total_length)
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if __name__ == '__main__':
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main()
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