+ sessions = self.vapi.nat44_user_session_dump(self.pg0.remote_ip4, 0)
+ self.assertEqual(len(sessions) - start_sessnum, 1)
+
+ stats = self.statistics.get_counter(
+ '/err/nat44-ed-out2in/drops due to TCP in transitory timeout')
+ out2in_drops = stats[0]
+ stats = self.statistics.get_counter(
+ '/err/nat44-ed-in2out/drops due to TCP in transitory timeout')
+ in2out_drops = stats[0]
+
+ # extra FIN packet out -> in - this should be dropped
+ p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
+ IP(src=self.pg1.remote_ip4, dst=self.nat_addr) /
+ TCP(sport=self.tcp_external_port, dport=self.tcp_port_out,
+ flags="FA", seq=300, ack=101))
+
+ self.pg1.add_stream(p)
+ self.pg_enable_capture(self.pg_interfaces)
+ self.pg_start()
+ self.pg0.assert_nothing_captured()
+
+ # extra ACK packet in -> out - this should be dropped
+ p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+ IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
+ TCP(sport=self.tcp_port_in, dport=self.tcp_external_port,
+ flags="A", seq=101, ack=301))
+ self.pg0.add_stream(p)
+ self.pg_enable_capture(self.pg_interfaces)
+ self.pg_start()
+ self.pg1.assert_nothing_captured()
+
+ stats = self.statistics.get_counter(
+ '/err/nat44-ed-out2in/drops due to TCP in transitory timeout')
+ self.assertEqual(stats[0] - out2in_drops, 1)
+ stats = self.statistics.get_counter(
+ '/err/nat44-ed-in2out/drops due to TCP in transitory timeout')
+ self.assertEqual(stats[0] - in2out_drops, 1)
+
+ self.sleep(3)
+ # extra ACK packet in -> out - this will cause session to be wiped
+ p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
+ IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
+ TCP(sport=self.tcp_port_in, dport=self.tcp_external_port,
+ flags="A", seq=101, ack=301))
+ self.pg0.add_stream(p)
+ self.pg_enable_capture(self.pg_interfaces)
+ self.pg_start()
+ self.pg1.assert_nothing_captured()
+ sessions = self.vapi.nat44_user_session_dump(self.pg0.remote_ip4, 0)