def create_session(packet_log):
listener = MockListener()
syn = packet_log[0]
listener.source_port = syn.sport - 1
conn = TCPSocket(listener)
conn.connect(syn.payload.dst, syn.dport)
# Change the sequence number so that we can test it
conn.seq = syn.seq
return listener, conn
def create_session(packet_log):
"""
Helper function to create a client session from a PCAP log. Sets up the
sequence numbers to match with the sequence numbers in the PCAP.
"""
listener = MockListener()
syn = packet_log[0]
listener.source_port = syn.sport - 1
conn = TCPSocket(listener)
conn.connect(syn.payload.dst, syn.dport)
# Change the sequence number so that we can test it
conn.seq = syn.seq
return listener, conn
def test_sends_reset():
"""The connection should send a RST packet when it's closed."""
listener = MockListener()
packet_log = rdpcap("test/inputs/tiniest-session.pcap")
listener, conn = create_session(packet_log)
conn._close()
syn_ack = packet_log[1]
listener.dispatch(syn_ack)
last_packet = listener.received_packets[-1]
assert last_packet.sprintf("%TCP.flags%") == "R"
def test_reset():
listener = MockListener()
packet_log = rdpcap("test/inputs/tiniest-session.pcap")
listener, conn = create_session(packet_log)
syn_ack = packet_log[1]
listener.dispatch(syn_ack)
reset = syn_ack.copy()
reset.payload.payload.flags = "R"
reset.seq += 1
listener.dispatch(reset)
assert conn.state == "CLOSED"
def test_bind_handshake():
packet_log = rdpcap("test/inputs/tiniest-session.pcap")
syn, syn_ack, ack, client_fin_ack, server_fin_ack, client_ack = packet_log
listener = MockListener()
conn = TCPSocket(listener)
conn.seq = syn_ack.seq
conn.bind(syn.payload.dst, syn.dport)
listener.dispatch(syn)
listener.dispatch(ack)
assert len(listener.received_packets) == 1
assert conn.state == "ESTABLISHED"
check_mostly_same(listener.received_packets[0], syn_ack)
def test_bind_handshake():
"""
We can do a handshake when we're the server (someone else initiates the
SYN).
"""
packet_log = rdpcap("test/inputs/tiniest-session.pcap")
syn, syn_ack, ack, client_fin_ack, server_fin_ack, client_ack = packet_log
listener = MockListener()
conn = TCPSocket(listener)
conn.seq = syn_ack.seq
conn.bind(syn.payload.dst, syn.dport)
listener.dispatch(syn)
listener.dispatch(ack)
assert len(listener.received_packets) == 1
assert conn.state == "ESTABLISHED"
check_mostly_same(listener.received_packets[0], syn_ack)
def test_syn():
"""When we connect, we should send a SYN."""
listener = MockListener()
conn = TCPSocket(listener)
conn.connect("localhost", 80)
assert conn.state == "SYN-SENT"
pkts = listener.received_packets
assert len(pkts) == 1
assert pkts[0].sprintf("%TCP.flags%") == "S"
def test_handshake_client():
listener = MockListener()
conn = TCPSocket(listener)
conn.connect("localhost", 80)
initial_seq = conn.seq
tcp_packet = TCP(dport=conn.src_port, flags="SA", seq=100, ack=initial_seq + 1)
syn_ack = Ether() / IP(dst=conn.src_ip) / tcp_packet
listener.dispatch(syn_ack)
assert conn.seq == initial_seq + 1
assert conn.state == "ESTABLISHED"
# We should have sent exactly two packets
# Check that they look okay
pkts = listener.received_packets
assert len(pkts) == 2
syn, ack = pkts
assert ack.seq == syn.seq + 1
assert syn.sprintf("%TCP.flags%") == "S"
assert ack.sprintf("%TCP.flags%") == "A"
def test_tiny_session_server():
"""
Test the whole tiny session, from a server POV.
"""
packet_log = rdpcap("test/inputs/tiniest-session.pcap")
syn, syn_ack = packet_log[:2]
listener = MockListener()
conn = TCPSocket(listener)
conn.seq = syn_ack.seq
conn.bind(syn.payload.dst, syn.dport)
check_replay(listener, conn, packet_log)
def test_closes_on_reset():
"""The connection should close when it receives a RST packet"""
listener = MockListener()
packet_log = rdpcap("test/inputs/tiniest-session.pcap")
listener, conn = create_session(packet_log)
syn_ack = packet_log[1]
listener.dispatch(syn_ack)
reset = syn_ack.copy()
reset.payload.payload.flags = "R"
reset.seq += 1
listener.dispatch(reset)
assert conn.state == "CLOSED"
