liteeth/test/model/mac.py

#
# This file is part of LiteEth.
#
# Copyright (c) 2015-2017 Florent Kermarrec <florent@enjoy-digital.fr>
# SPDX-License-Identifier: BSD-2-Clause

import math
import binascii

from litex.soc.interconnect.stream_sim import *

from liteeth.common import *

# Helpers ------------------------------------------------------------------------------------------

def print_mac(s):
    print_with_prefix(s, "[MAC]")

preamble = split_bytes(eth_preamble, 8, "little")

def crc32(l):
    crc = []
    crc_bytes = split_bytes(binascii.crc32(bytes(l)), 4, "little")
    for byte in crc_bytes:
        crc.append(int(byte))
    return crc

# MAC Packet ---------------------------------------------------------------------------------------

class MACPacket(Packet):
    def __init__(self, init=[]):
        Packet.__init__(self, init)
        self.preamble_error = False
        self.crc_error      = False

    def check_remove_preamble(self):
        if comp(self[0:8], preamble):
            for i in range(8):
                self.pop(0)
            return False
        else:
            return True

    def check_remove_crc(self):
        if comp(self[-4:], crc32(self[:-4])):
            for i in range(4):
                self.pop()
            return False
        else:
            return True

    def decode_remove_header(self):
        header = []
        for byte in self[:mac_header.length]:
            header.append(self.pop(0))
        for k, v in sorted(mac_header.fields.items()):
            setattr(self, k, get_field_data(v, header))

    def decode(self):
        self.preamble_error = self.check_remove_preamble()
        self.crc_error = self.check_remove_crc()
        if self.crc_error or self.preamble_error:
            raise ValueError  # XXX handle this properly
        else:
            self.decode_remove_header()

    def encode_header(self):
        header = 0
        for k, v in sorted(mac_header.fields.items()):
            value = merge_bytes(split_bytes(getattr(self, k),
                                            math.ceil(v.width/8)),
                                            "little")
            header += (value << v.offset+(v.byte*8))
        for d in split_bytes(header, mac_header.length):
            self.insert(0, d)

    def insert_crc(self):
        for d in crc32(self):
            self.append(d)

    def insert_preamble(self):
        for d in reversed(preamble):
            self.insert(0, d)

    def encode(self):
        self.encode_header()
        self.insert_crc()
        self.insert_preamble()

    def __repr__(self):
        r = "--------\n"
        for k in sorted(mac_header.fields.keys()):
            r += k + " : 0x{:0x}\n".format(getattr(self, k))
        r += "payload: "
        for d in self:
            r += "{:02x}".format(d)
        return r

# MAC ----------------------------------------------------------------------------------------------

class MAC(Module):
    def __init__(self, phy, debug=False, loopback=False):
        self.phy          = phy
        self.debug        = debug
        self.loopback     = loopback
        self.rx_packet    = MACPacket()

        self.ip_callback  = None
        self.arp_callback = None

        phy.set_mac_callback(self.callback)

    def set_ip_callback(self, callback):
        self.ip_callback = callback

    def set_arp_callback(self, callback):
        self.arp_callback = callback

    def send(self, packet):
        if self.debug:
            print_mac(">>>>>>>>")
            print_mac(packet)
        packet.encode()
        self.phy.send(packet)

    def callback(self, datas):
        packet = MACPacket(datas)
        packet.decode()
        if self.debug:
            print_mac("<<<<<<<<")
            print_mac(packet)
        if self.loopback:
            self.send(packet)
        else:
            if packet.ethernet_type == ethernet_type_ip:
                if self.ip_callback is not None:
                    self.ip_callback(packet)
            elif packet.ethernet_type == ethernet_type_arp:
                if self.arp_callback is not None:
                    self.arp_callback(packet)
            else:
                raise ValueError  # XXX handle this properly