[6320] | 1 | # -*- coding: utf-8 -*- |
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| 2 | """ |
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| 3 | ------------------------------------------------------------------------------ |
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| 4 | Mango 802.11 Reference Design Experiments Framework |
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| 5 | - Transport Unicast Ethernet IP/UDP Python Socket Implementation |
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| 6 | ------------------------------------------------------------------------------ |
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| 7 | License: Copyright 2019 Mango Communications, Inc. All rights reserved. |
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| 8 | Use and distribution subject to terms in LICENSE.txt |
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| 9 | ------------------------------------------------------------------------------ |
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| 10 | |
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| 11 | This module provides the unicast Ethernet IP/UDP transport based on the python |
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| 12 | socket class. |
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| 13 | |
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| 14 | Functions: |
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| 15 | TransportEthIpUdpPy() -- Unicast Ethernet UDP transport based on python |
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| 16 | sockets |
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| 17 | |
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| 18 | """ |
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| 19 | |
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| 20 | import re |
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| 21 | import time |
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| 22 | import socket |
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| 23 | |
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| 24 | from . import transport_eth_ip_udp as tp |
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| 25 | from . import exception as ex |
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| 26 | |
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| 27 | |
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| 28 | __all__ = ['TransportEthIpUdpPy'] |
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| 29 | |
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| 30 | |
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| 31 | class TransportEthIpUdpPy(tp.TransportEthIpUdp): |
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| 32 | """Class for Ethernet IP/UDP Transport class using Python libraries. |
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| 33 | |
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| 34 | Attributes: |
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| 35 | See TransportEthIpUdp for all attributes |
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| 36 | """ |
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| 37 | def __init__(self): |
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| 38 | super(TransportEthIpUdpPy, self).__init__() |
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| 39 | |
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| 40 | |
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| 41 | def send(self, payload, robust=True): |
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| 42 | """Send a message over the transport. |
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| 43 | |
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| 44 | Args: |
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| 45 | payload (bytes): Data to be sent over the socket |
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| 46 | robust (bool): Is a response required |
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| 47 | """ |
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| 48 | |
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| 49 | if robust: |
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| 50 | self.hdr.response_required() |
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| 51 | else: |
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| 52 | self.hdr.response_not_required() |
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| 53 | |
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| 54 | self.hdr.set_length(len(payload)) |
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| 55 | self.hdr.increment() |
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| 56 | |
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| 57 | # Assemble the packet from the transport header and payload |
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| 58 | # The wlan_exp C assumes the bytes starting at 'payload' here are u32 aligned |
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| 59 | # in the full Ethernet packet. The transport header is 10 bytes by design, |
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| 60 | # which aligns the end of the transport header to a 4-byte boundary when |
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| 61 | # appended to a 14-byte Ethernet + 20-byte IP + 8-byte UDP header |
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| 62 | # Different padding would be required here if the sizes of the headers |
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| 63 | # before the transport header change |
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| 64 | data = bytes(self.hdr.serialize() + payload) |
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| 65 | |
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| 66 | size = self.sock.sendto(data, (self.ip_address, self.unicast_port)) |
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| 67 | |
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| 68 | if size != len(data): |
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| 69 | print("Only {} of {} bytes of data sent".format(size, len(data))) |
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| 70 | |
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| 71 | |
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| 72 | def receive(self, timeout=None): |
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| 73 | """Return a response from the transport. |
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| 74 | |
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| 75 | Args: |
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| 76 | timeout (float): Time (in float seconds) to wait before raising |
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| 77 | an execption. If no value is specified, then it will use the |
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| 78 | default transport timeout (self.timeout) |
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| 79 | |
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| 80 | This function will block until a response is received or a timeout |
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| 81 | occurs. If a timeout occurs, it will raise a TransportError exception. |
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| 82 | """ |
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| 83 | reply = b'' |
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| 84 | |
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| 85 | if timeout is None: |
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| 86 | timeout = self.timeout |
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| 87 | else: |
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| 88 | timeout += self.timeout # Extend timeout to not run in to race conditions |
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| 89 | |
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| 90 | received_resp = 0 |
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| 91 | start_time = time.time() |
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| 92 | |
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| 93 | while received_resp == 0: |
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| 94 | recv_data = [] |
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| 95 | |
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| 96 | try: |
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| 97 | # Call the lowl-level socket recvfrom |
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| 98 | # Second return value is recv_addr, not used here |
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| 99 | # Size arg is set to larger than largest packet |
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| 100 | (recv_data, _) = self.sock.recvfrom(10000) |
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| 101 | |
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| 102 | except socket.error as err: |
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| 103 | expr = re.compile("timed out") |
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| 104 | if not expr.match(str(err)): |
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| 105 | print("Failed to receive UDP packet.\nError message:\n{}".format(err)) |
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| 106 | |
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| 107 | if len(recv_data) > 0: |
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| 108 | hdr_len = self.hdr.sizeof() |
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| 109 | # print("Received pkt from", recv_addr) |
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| 110 | if (self.hdr.is_reply(recv_data[0:hdr_len])): |
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| 111 | reply = recv_data[hdr_len:] |
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| 112 | received_resp = 1 |
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| 113 | |
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| 114 | if ((time.time() - start_time) > timeout ) and (received_resp == 0): |
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| 115 | raise ex.TransportError(self, "Transport receive timed out.") |
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| 116 | |
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| 117 | return reply |
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| 118 | |
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| 119 | |
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| 120 | def receive_nb(self): |
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| 121 | """Return a response from the transport. |
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| 122 | |
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| 123 | This function will not block and should be called in a polling loop |
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| 124 | until a response is received. |
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| 125 | """ |
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| 126 | reply = b'' |
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| 127 | recv_data = [] |
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| 128 | |
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| 129 | try: |
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| 130 | # Call the lowl-level socket recvfrom |
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| 131 | # Second return value is recv_addr, not used here |
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| 132 | # Size arg is set to larger than largest packet |
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| 133 | (recv_data, _) = self.sock.recvfrom(10000) |
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| 134 | except socket.error as err: |
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| 135 | expr = re.compile("timed out") |
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| 136 | if not expr.match(str(err)): |
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| 137 | print("Failed to receive UDP packet.\nError message:\n{}".format(err)) |
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| 138 | |
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| 139 | if len(recv_data) > 0: |
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| 140 | hdr_len = self.hdr.sizeof() |
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| 141 | if (self.hdr.is_reply(recv_data[0:hdr_len])): |
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| 142 | reply = recv_data[hdr_len:] |
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| 143 | |
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| 144 | return reply |
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| 145 | |
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| 146 | |
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| 147 | # End Class |
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