traceparse: bsd/macos parser with multipath hops and annotations

src/netcheck/traceparse.py

@@ -110,3 +110,40 @@ def parse_windows(text: str) -> list[TraceHop]:
             rdns = None
         hops.append(finalize_hop(TraceHop(ttl=ttl, ip=ip, reverse_dns=rdns, probes=probes)))
     return hops
+
+
+_BSD_CONTINUATION_RE = re.compile(r"^\s+\S")
+
+
+def parse_darwin(text: str) -> list[TraceHop]:
+    hops: list[TraceHop] = []
+    for line in text.splitlines():
+        match = _HOP_LINE_RE.match(line)
+        if match:
+            ttl, body = int(match.group(1)), match.group(2)
+            rdns, ip = _unix_host_and_ip(body)
+            hops.append(
+                TraceHop(
+                    ttl=ttl,
+                    ip=ip,
+                    reverse_dns=rdns,
+                    probes=_unix_probes(body),
+                    annotations=_unix_annotations(body),
+                )
+            )
+            continue
+        if not hops or not _BSD_CONTINUATION_RE.match(line):
+            continue
+        # BSD prints one continuation line per probe that came back from a
+        # different router than the hop's first probe.
+        hop = hops[-1]
+        _, extra_ip = _unix_host_and_ip(line)
+        hop.probes.extend(_unix_probes(line))
+        if extra_ip and extra_ip != hop.ip:
+            marker = f"alt:{extra_ip}"
+            if marker not in hop.annotations:
+                hop.annotations.append(marker)
+        for token in _unix_annotations(line):
+            if token not in hop.annotations:
+                hop.annotations.append(token)
+    return [finalize_hop(hop) for hop in hops]

tests/fixtures/traceroute/darwin/bsd_basic.txt

@@ -0,0 +1,6 @@
+traceroute to one.one.one.one (1.1.1.1), 64 hops max, 52 byte packets
+ 1  192.168.1.1 (192.168.1.1)  2.145 ms  1.902 ms  1.870 ms
+ 2  10.64.0.1 (10.64.0.1)  9.001 ms  8.940 ms  8.870 ms
+ 3  * * *
+ 4  ae-1.r01.ams.example.net (77.88.1.5)  12.400 ms  12.100 ms  12.220 ms
+ 5  one.one.one.one (1.1.1.1)  13.900 ms  13.700 ms  13.610 ms

tests/fixtures/traceroute/darwin/bsd_multipath.txt

@@ -0,0 +1,8 @@
+traceroute to 203.0.113.9 (203.0.113.9), 64 hops max, 52 byte packets
+ 1  192.168.1.1 (192.168.1.1)  2.100 ms  1.900 ms  1.850 ms
+ 2  10.64.0.1 (10.64.0.1)  9.001 ms
+    10.64.0.5 (10.64.0.5)  9.220 ms
+    10.64.0.1 (10.64.0.1)  8.870 ms
+ 3  * 11.200 ms *
+ 4  border.example.net (198.51.100.7)  15.100 ms !H  15.200 ms  15.050 ms
+ 5  filtered.example.net (198.51.100.9)  16.000 ms !X  16.100 ms !X  16.200 ms !X

tests/test_traceparse.py

@@ -141,3 +141,45 @@ def test_windows_destination_unreachable_hop_keeps_its_ip(trace_fixture):
 
 def test_windows_parser_tolerates_empty_input():
     assert parse_windows("") == []
+
+
+from netcheck.traceparse import parse_darwin
+
+
+def test_darwin_basic_hops_match_the_gnu_shape(trace_fixture):
+    hops = parse_darwin(trace_fixture("darwin", "bsd_basic.txt"))
+    assert [h.ttl for h in hops] == [1, 2, 3, 4, 5]
+    assert hops[0].ip == "192.168.1.1"
+    assert hops[0].reverse_dns is None
+    assert hops[3].reverse_dns == "ae-1.r01.ams.example.net"
+    assert hops[2].probes == [None, None, None]
+
+
+def test_darwin_merges_continuation_lines_into_one_hop(trace_fixture):
+    hops = parse_darwin(trace_fixture("darwin", "bsd_multipath.txt"))
+    assert [h.ttl for h in hops] == [1, 2, 3, 4, 5]
+    hop = hops[1]
+    assert hop.probes == [9.001, 9.22, 8.87]
+    assert hop.ip == "10.64.0.1"
+
+
+def test_darwin_records_alternate_addresses_for_a_multipath_hop(trace_fixture):
+    hops = parse_darwin(trace_fixture("darwin", "bsd_multipath.txt"))
+    assert "alt:10.64.0.5" in hops[1].annotations
+    assert "alt:10.64.0.1" not in hops[1].annotations
+
+
+def test_darwin_keeps_bsd_only_annotations(trace_fixture):
+    hops = parse_darwin(trace_fixture("darwin", "bsd_multipath.txt"))
+    assert hops[3].annotations == ["!H"]
+    assert hops[4].annotations == ["!X"]
+
+
+def test_darwin_partial_timeout_hop_keeps_positions(trace_fixture):
+    hops = parse_darwin(trace_fixture("darwin", "bsd_multipath.txt"))
+    assert hops[2].probes == [None, 11.2, None]
+    assert hops[2].loss_pct == pytest.approx(66.667)
+
+
+def test_darwin_parser_tolerates_empty_input():
+    assert parse_darwin("") == []