diff options
Diffstat (limited to 'test/test_nat.py')
| -rw-r--r-- | test/test_nat.py | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/test/test_nat.py b/test/test_nat.py index 5baadd89863..a705bd98fc0 100644 --- a/test/test_nat.py +++ b/test/test_nat.py @@ -139,6 +139,7 @@ class MethodHolder(VppTestCase): self.verify_no_nat44_user() self.vapi.nat_set_timeouts() self.vapi.nat_set_addr_and_port_alloc_alg() + self.vapi.nat_set_mss_clamping() def nat44_add_static_mapping(self, local_ip, external_ip='0.0.0.0', local_port=0, external_port=0, vrf_id=0, @@ -1002,6 +1003,21 @@ class MethodHolder(VppTestCase): # sourceIPv4Address self.assertEqual(src_addr, record[8]) + def verify_mss_value(self, pkt, mss): + """ + Verify TCP MSS value + + :param pkt: + :param mss: + """ + if not pkt.haslayer(IP) or not pkt.haslayer(TCP): + raise TypeError("Not a TCP/IP packet") + + for option in pkt[TCP].options: + if option[0] == 'MSS': + self.assertEqual(option[1], mss) + self.assert_tcp_checksum_valid(pkt) + class TestNAT44(MethodHolder): """ NAT44 Test Cases """ @@ -3295,6 +3311,42 @@ class TestNAT44(MethodHolder): nsessions = nsessions + user.nsessions self.assertLess(nsessions, 2 * max_sessions) + def test_mss_clamping(self): + """ TCP MSS clamping """ + self.nat44_add_address(self.nat_addr) + self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index) + self.vapi.nat44_interface_add_del_feature(self.pg1.sw_if_index, + is_inside=0) + + 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="S", options=[('MSS', 1400)])) + + self.vapi.nat_set_mss_clamping(enable=1, mss_value=1000) + self.pg0.add_stream(p) + self.pg_enable_capture(self.pg_interfaces) + self.pg_start() + capture = self.pg1.get_capture(1) + # Negotiated MSS value greater than configured - changed + self.verify_mss_value(capture[0], 1000) + + self.vapi.nat_set_mss_clamping(enable=0) + self.pg0.add_stream(p) + self.pg_enable_capture(self.pg_interfaces) + self.pg_start() + capture = self.pg1.get_capture(1) + # MSS clamping disabled - negotiated MSS unchanged + self.verify_mss_value(capture[0], 1400) + + self.vapi.nat_set_mss_clamping(enable=1, mss_value=1500) + self.pg0.add_stream(p) + self.pg_enable_capture(self.pg_interfaces) + self.pg_start() + capture = self.pg1.get_capture(1) + # Negotiated MSS value smaller than configured - unchanged + self.verify_mss_value(capture[0], 1400) + def tearDown(self): super(TestNAT44, self).tearDown() if not self.vpp_dead: |