liteeth/test/model/icmp.py

#
# This file is part of LiteEth.
#
# Copyright (c) 2015-2019 Florent Kermarrec <florent@enjoy-digital.fr>
# SPDX-License-Identifier: BSD-2-Clause

import math

from litex.soc.interconnect.stream_sim import *

from liteeth.common import *

from test.model import ip

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

def print_icmp(s):
    print_with_prefix(s, "[ICMP]")


# ICMP Packet --------------------------------------------------------------------------------------

class ICMPPacket(Packet):
    def __init__(self, init=[]):
        Packet.__init__(self, init)

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

    def encode(self):
        header = 0
        for k, v in sorted(icmp_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, icmp_header.length):
            self.insert(0, d)

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

# ICMP ---------------------------------------------------------------------------------------------

class ICMP(Module):
    def __init__(self, ip, ip_address, debug=False):
        self.ip         = ip
        self.ip_address = ip_address
        self.debug      = debug
        self.tx_packets = []
        self.tx_packet  = ICMPPacket()
        self.rx_packet  = ICMPPacket()

        self.ip.set_icmp_callback(self.callback)

    def send(self, packet):
        packet.encode()
        if self.debug:
            print_icmp(">>>>>>>>")
            print_icmp(packet)
        ip_packet = ip.IPPacket(packet)
        ip_packet.version         = 0x4
        ip_packet.ihl             = 0x5
        ip_packet.total_length    = len(packet) + ip_packet.ihl
        ip_packet.identification  = 0
        ip_packet.flags           = 0
        ip_packet.fragment_offset = 0
        ip_packet.ttl             = 0x80
        ip_packet.sender_ip       = self.ip_address
        ip_packet.target_ip       = 0x12345678  # XXX
        ip_packet.checksum        = 0
        ip_packet.protocol        = icmp_protocol
        self.ip.send(ip_packet)

    def callback(self, packet):
        packet = ICMPPacket(packet)
        packet.decode()
        if self.debug:
            print_icmp("<<<<<<<<")
            print_icmp(packet)
        self.process(packet)

    def process(self, packet):
        pass