litex/liteeth/test/model/ip.py

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import math
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from liteeth.common import *
from liteeth.test.common import *
from liteeth.test.model import mac
def print_ip(s):
print_with_prefix(s, "[IP]")
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def carry_around_add(a, b):
c = a + b
return (c & 0xffff) + (c >> 16)
def checksum(msg):
s = 0
for i in range(0, len(msg), 2):
w = msg[i] + (msg[i+1] << 8)
s = carry_around_add(s, w)
return ~s & 0xffff
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# IP model
class IPPacket(Packet):
def __init__(self, init=[]):
Packet.__init__(self, init)
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def get_checksum(self):
return self[10] | (self[11] << 8)
def check_checksum(self):
return checksum(self[:ipv4_header_len]) == 0
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def decode(self):
header = []
for byte in self[:ipv4_header_len]:
header.append(self.pop(0))
for k, v in sorted(ipv4_header.items()):
setattr(self, k, get_field_data(v, header))
def encode(self):
header = 0
for k, v in sorted(ipv4_header.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, ipv4_header_len):
self.insert(0, d)
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def insert_checksum(self):
self[10] = 0
self[11] = 0
c = checksum(self[:ipv4_header_len])
self[10] = c & 0xff
self[11] = (c >> 8) & 0xff
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def __repr__(self):
r = "--------\n"
for k in sorted(ipv4_header.keys()):
r += k + " : 0x%x" %getattr(self,k) + "\n"
r += "payload: "
for d in self:
r += "%02x" %d
return r
class IP(Module):
def __init__(self, mac, mac_address, ip_address, debug=False, loopback=False):
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self.mac = mac
self.mac_address = mac_address
self.ip_address = ip_address
self.debug = debug
self.loopback = loopback
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self.rx_packet = IPPacket()
self.table = {}
self.request_pending = False
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self.udp_callback = None
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self.icmp_callback = None
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self.mac.set_ip_callback(self.callback)
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def set_udp_callback(self, callback):
self.udp_callback = callback
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def set_icmp_callback(self, callback):
self.icmp_callback = callback
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def send(self, packet):
packet.encode()
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packet.insert_checksum()
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if self.debug:
print_ip(">>>>>>>>")
print_ip(packet)
mac_packet = mac.MACPacket(packet)
mac_packet.target_mac = 0x12345678abcd # XXX
mac_packet.sender_mac = self.mac_address
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mac_packet.ethernet_type = ethernet_type_ip
self.mac.send(mac_packet)
def callback(self, packet):
packet = IPPacket(packet)
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if not packet.check_checksum():
received = packet.get_checksum()
packet.insert_checksum()
expected = packet.get_checksum()
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raise ValueError("Checksum error received %04x / expected %04x" %(received, expected))
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packet.decode()
if self.debug:
print_ip("<<<<<<<<")
print_ip(packet)
if self.loopback:
self.send(packet)
else:
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if packet.version != 0x4:
raise ValueError
if packet.ihl != 0x5:
raise ValueError
self.process(packet)
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def process(self, packet):
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if packet.protocol == udp_protocol:
if self.udp_callback is not None:
self.udp_callback(packet)
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elif packet.protocol == icmp_protocol:
if self.icmp_callback is not None:
self.icmp_callback(packet)
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if __name__ == "__main__":
from liteeth.test.model.dumps import *
from liteeth.test.model.mac import *
errors = 0
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# UDP packet
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packet = MACPacket(udp)
packet.decode_remove_header()
#print(packet)
packet = IPPacket(packet)
# check decoding
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errors += not packet.check_checksum()
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packet.decode()
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#print(packet)
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errors += verify_packet(packet, {})
# check encoding
packet.encode()
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packet.insert_checksum()
errors += not packet.check_checksum()
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packet.decode()
#print(packet)
errors += verify_packet(packet, {})
print("ip errors " + str(errors))