source: ReferenceDesigns/w3_802.11/python/wlan_exp/transport/transport_eth_ip_udp_py_broadcast.py

# -*- coding: utf-8 -*-
"""
------------------------------------------------------------------------------
Mango 802.11 Reference Design Experiments Framework 
    - Transport Broadcast Ethernet IP/UDP Python Socket Implementation
------------------------------------------------------------------------------
License:   Copyright 2019 Mango Communications, Inc. All rights reserved.
           Use and distribution subject to terms in LICENSE.txt
------------------------------------------------------------------------------

This module provides the broadcast Ethernet IP/UDP transport based on the 
python socket class.

Functions:
    TransportEthUdpPyBcast() -- Broadcast Ethernet UDP transport based on 
        python sockets

"""

from . import transport_eth_ip_udp as tp


__all__ = ['TransportEthIpUdpPyBroadcast']


class TransportEthIpUdpPyBroadcast(tp.TransportEthIpUdp):
    """Class for Ethernet IP/UDP Broadcast Transport class using Python libraries.
       
    Attributes:
        See TransportEthIpUdp for attributes
        network_config -- A NetworkConfiguration that describes the transport configuration.
    
    The transport will send packets to the first host interface as the subnet 
    for the broadcast address.
    """
    network_config = None
    
    def __init__(self, network_config=None):
        super(TransportEthIpUdpPyBroadcast, self).__init__()

        if network_config is not None:
            self.network_config = network_config
        else:
            from . import config

            self.network_config = config.NetworkConfiguration()
        
        self.set_default_config()

        
    def set_default_config(self):
        """Set the default configuration of a Broadcast transport."""
        unicast_port   = self.network_config.get_param('unicast_port')
        broadcast_port = self.network_config.get_param('broadcast_port')
        host_id        = self.network_config.get_param('host_id')
        broadcast_addr = self.network_config.get_param('broadcast_address')
        
        # Set default values of the Transport
        self.set_ip_address(broadcast_addr)
        self.set_unicast_port(unicast_port)
        self.set_broadcast_port(broadcast_port)
        self.set_src_id(host_id)
        self.set_dest_id(0xFFFF)
        self.timeout = 1


    def set_ip_address(self, ip_addr):
        """Sets the IP address of the Broadcast transport.
        
        This method will take an IP address of the form W.X.Y.Z and set the
        transport IP address to W.X.Y.255 so that it is a proper broadcast
        address.
        """
        #expr = re.compile('\.')
        #tmp = [int(n) for n in expr.split(ip_addr)]
        tmp = [int(n) for n in ip_addr.split('.')]
        self.ip_address = "{0:d}.{1:d}.{2:d}.255".format(tmp[0], tmp[1], tmp[2])

    
    def send(self, payload, robust=False):
        """Send a broadcast packet over the transport.
        
        Attributes:
            data -- Data to be sent over the socket
        """
        if robust:
            print("WARNING: Not able to send broadcast robust packets.")        
        
        self.hdr.response_not_required()
        self.hdr.set_length(len(payload))
        self.hdr.increment()

        # Assemble the packet from the transport header and payload
        # The wlan_exp C assumes the bytes starting at 'payload' here are u32 aligned
        #  in the full Ethernet packet. The transport header is 10 bytes by design,
        #  which aligns the end of the transport header to a 4-byte boundary when
        #  appended to a 14-byte Ethernet + 20-byte IP + 8-byte UDP header
        # Different padding would be required here if the sizes of the headers 
        #  before the transport header change
        data = bytes(self.hdr.serialize() + payload)        
        
        size = self.sock.sendto(data, (self.ip_address, self.broadcast_port))
        
        if size != len(data):
            print("Only {} of {} bytes of data sent".format(size, len(data)))


    def receive(self, timeout=None):
        """Not used on a broadcast transport"""
        super(TransportEthIpUdpPyBroadcast, self).receive()


# End Class