1 files changed, 136 insertions, 0 deletions
diff --git a/tests/pytests/utils.py b/tests/pytests/utils.py
new file mode 100644
index 0000000..4b995d4
--- /dev/null
+++ b/tests/pytests/utils.py
@@ -0,0 +1,136 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+from contextlib import contextmanager
+import random
+import ssl
+import struct
+import time
+
+import dns
+import dns.message
+import pytest
+
+
+# default net.tcp_in_idle is 10s, TCP_DEFER_ACCEPT 3s, some extra for
+# Python handling / edge cases
+MAX_TIMEOUT = 16
+
+
+def receive_answer(sock):
+    answer_total_len = 0
+    data = sock.recv(2)
+    if not data:
+        return None
+    answer_total_len = struct.unpack_from("!H", data)[0]
+
+    answer_received_len = 0
+    data_answer = b''
+    while answer_received_len < answer_total_len:
+        data_chunk = sock.recv(answer_total_len - answer_received_len)
+        if not data_chunk:
+            return None
+        data_answer += data_chunk
+        answer_received_len += len(data_answer)
+
+    return data_answer
+
+
+def receive_parse_answer(sock):
+    data_answer = receive_answer(sock)
+
+    if data_answer is None:
+        raise BrokenPipeError("kresd closed connection")
+
+    msg_answer = dns.message.from_wire(data_answer, one_rr_per_rrset=True)
+    return msg_answer
+
+
+def prepare_wire(
+        qname='localhost.',
+        qtype=dns.rdatatype.A,
+        qclass=dns.rdataclass.IN,
+        msgid=None):
+    """Utility function to generate DNS wire format message"""
+    msg = dns.message.make_query(qname, qtype, qclass, use_edns=True)
+    if msgid is not None:
+        msg.id = msgid
+    return msg.to_wire(), msg.id
+
+
+def prepare_buffer(wire, datalen=None):
+    """Utility function to prepare TCP buffer from DNS message in wire format"""
+    assert isinstance(wire, bytes)
+    if datalen is None:
+        datalen = len(wire)
+    return struct.pack("!H", datalen) + wire
+
+
+def get_msgbuff(qname='localhost.', qtype=dns.rdatatype.A, msgid=None):
+    wire, msgid = prepare_wire(qname, qtype, msgid=msgid)
+    buff = prepare_buffer(wire)
+    return buff, msgid
+
+
+def get_garbage(length):
+    return bytes(random.getrandbits(8) for _ in range(length))
+
+
+def get_prefixed_garbage(length):
+    data = get_garbage(length)
+    return prepare_buffer(data)
+
+
+def try_ping_alive(sock, msgid=None, close=False):
+    try:
+        ping_alive(sock, msgid)
+    except AssertionError:
+        return False
+    finally:
+        if close:
+            sock.close()
+    return True
+
+
+def ping_alive(sock, msgid=None):
+    buff, msgid = get_msgbuff(msgid=msgid)
+    sock.sendall(buff)
+    answer = receive_parse_answer(sock)
+    assert answer.id == msgid
+
+
+@contextmanager
+def expect_kresd_close(rst_ok=False):
+    with pytest.raises(BrokenPipeError):
+        try:
+            time.sleep(0.2)  # give kresd time to close connection with TCP FIN
+            yield
+        except ConnectionResetError as ex:
+            if rst_ok:
+                raise BrokenPipeError from ex
+            pytest.skip("kresd closed connection with TCP RST")
+        pytest.fail("kresd didn't close the connection")
+
+
+def make_ssl_context(insecure=False, verify_location=None, extra_options=None):
+    # set TLS v1.2+
+    context = ssl.SSLContext(ssl.PROTOCOL_TLS)
+    context.options |= ssl.OP_NO_SSLv2
+    context.options |= ssl.OP_NO_SSLv3
+    context.options |= ssl.OP_NO_TLSv1
+    context.options |= ssl.OP_NO_TLSv1_1
+
+    if extra_options is not None:
+        for option in extra_options:
+            context.options |= option
+
+    if insecure:
+        # turn off certificate verification
+        context.check_hostname = False
+        context.verify_mode = ssl.CERT_NONE
+    else:
+        context.verify_mode = ssl.CERT_REQUIRED
+        context.check_hostname = True
+
+        if verify_location is not None:
+            context.load_verify_locations(verify_location)
+
+    return context