netsleuth/tests/test_icmp_win_parse.py

84 lines
2.8 KiB
Python

from __future__ import annotations
import struct
import pytest
from netcheck.probes.icmp_win import (
IP_DEST_HOST_UNREACHABLE,
IP_REQ_TIMED_OUT,
IP_SUCCESS,
IP_TTL_EXPIRED_TRANSIT,
classify_status,
parse_echo_reply,
)
def make_reply(address: str, status: int, rtt: int, ttl: int, pointer_size: int = 8) -> bytes:
# ICMP_ECHO_REPLY: IPAddr(4) Status(4) RoundTripTime(4) DataSize(2) Reserved(2)
# then a pointer (Data), then IP_OPTION_INFORMATION { Ttl Tos Flags OptionsSize }
# followed by another pointer. Both pointers are alignment-padded to their width.
packed = struct.pack("<4B", *(int(o) for o in address.split(".")))
head = packed + struct.pack("<IIHH", status, rtt, 32, 0)
head += b"\x00" * (pointer_size - (len(head) % pointer_size) if len(head) % pointer_size else 0)
head += b"\x00" * pointer_size
head += struct.pack("<4B", ttl, 0, 0, 0)
head += b"\x00" * (pointer_size - 4 if pointer_size > 4 else 0)
head += b"\x00" * pointer_size
return head
def test_parses_a_successful_reply_on_64_bit():
reply = parse_echo_reply(make_reply("1.1.1.1", IP_SUCCESS, 12, 57), pointer_size=8)
assert reply.address == "1.1.1.1"
assert reply.status == IP_SUCCESS
assert reply.rtt_ms == 12.0
assert reply.ttl == 57
def test_parses_a_successful_reply_on_32_bit():
reply = parse_echo_reply(make_reply("8.8.4.4", IP_SUCCESS, 9, 120, pointer_size=4), pointer_size=4)
assert reply.address == "8.8.4.4"
assert reply.rtt_ms == 9.0
assert reply.ttl == 120
def test_address_bytes_are_read_in_network_order():
reply = parse_echo_reply(make_reply("192.168.1.34", IP_SUCCESS, 1, 64))
assert reply.address == "192.168.1.34"
def test_a_ttl_expired_reply_keeps_the_intermediate_router_address():
reply = parse_echo_reply(make_reply("10.64.0.1", IP_TTL_EXPIRED_TRANSIT, 8, 253))
assert reply.address == "10.64.0.1"
assert reply.status == IP_TTL_EXPIRED_TRANSIT
assert reply.rtt_ms == 8.0
def test_a_timed_out_reply_has_no_address_and_no_rtt():
reply = parse_echo_reply(make_reply("0.0.0.0", IP_REQ_TIMED_OUT, 0, 0))
assert reply.address is None
assert reply.rtt_ms is None
assert reply.status == IP_REQ_TIMED_OUT
def test_a_truncated_buffer_is_reported_as_an_error_not_an_exception():
reply = parse_echo_reply(b"\x01\x02")
assert reply.address is None
assert reply.rtt_ms is None
assert reply.status == -1
@pytest.mark.parametrize(
("status", "expected"),
[
(IP_SUCCESS, "ok"),
(IP_TTL_EXPIRED_TRANSIT, "ttl_expired"),
(IP_REQ_TIMED_OUT, "timeout"),
(IP_DEST_HOST_UNREACHABLE, "unreachable"),
(-1, "error"),
(11050, "error"),
],
)
def test_status_classification(status, expected):
assert classify_status(status) == expected