nat: fix LRU blocked by inactive session

This fixes a situation where long-lived inactive session blocks LRU
list. Solution is to have multiple LRU lists based on session type.
This helps because session timeout is same for all sessions of same
type.

Type: fix

Signed-off-by: Klement Sekera <ksekera@cisco.com>
Change-Id: I5e54b2aab73b23911d6518d42e8c3f166c69a38c

1 files changed, 105 insertions, 0 deletions

diff --git a/src/plugins/nat/test/test_nat.py b/src/plugins/nat/test/test_nat.py
index a8e2af763d0..2ba7a9b78f3 100644
--- a/src/plugins/nat/test/test_nat.py
+++ b/src/plugins/nat/test/test_nat.py
@@ -7059,6 +7059,111 @@ class TestNAT44EndpointDependent(MethodHolder):
         self.logger.info(self.vapi.cli("show nat timeouts"))
 
 
+class TestNAT44EndpointDependent2(MethodHolder):
+    """ Endpoint-Dependent mapping and filtering extra test cases """
+
+    translation_buckets = 5
+
+    @classmethod
+    def setUpConstants(cls):
+        super(TestNAT44EndpointDependent2, cls).setUpConstants()
+        cls.vpp_cmdline.extend([
+            "nat", "{", "endpoint-dependent",
+            "translation hash buckets %d" % cls.translation_buckets,
+            "}"
+        ])
+
+    @classmethod
+    def setUpClass(cls):
+        super(TestNAT44EndpointDependent2, cls).setUpClass()
+        cls.vapi.cli("set log class nat level debug")
+
+        cls.nat_addr = '10.0.0.3'
+
+        cls.create_pg_interfaces(range(2))
+
+        for i in cls.pg_interfaces:
+            i.admin_up()
+            i.config_ip4()
+            i.resolve_arp()
+
+    def setUp(self):
+        super(TestNAT44EndpointDependent2, self).setUp()
+        self.vapi.nat_set_timeouts(
+            udp=1, tcp_established=7440, tcp_transitory=30, icmp=1)
+        self.nat44_add_address(self.nat_addr)
+        flags = self.config_flags.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index, flags=flags, is_add=1)
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg1.sw_if_index, is_add=1)
+
+    @classmethod
+    def tearDownClass(cls):
+        super(TestNAT44EndpointDependent2, cls).tearDownClass()
+
+    def init_tcp_session(self, in_if, out_if, sport, ext_dport):
+        # SYN packet in->out
+        p = (Ether(src=in_if.remote_mac, dst=in_if.local_mac) /
+             IP(src=in_if.remote_ip4, dst=out_if.remote_ip4) /
+             TCP(sport=sport, dport=ext_dport, flags="S"))
+        in_if.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = out_if.get_capture(1)
+        p = capture[0]
+        tcp_port_out = p[TCP].sport
+
+        # SYN + ACK packet out->in
+        p = (Ether(src=out_if.remote_mac, dst=out_if.local_mac) /
+             IP(src=out_if.remote_ip4, dst=self.nat_addr) /
+             TCP(sport=ext_dport, dport=tcp_port_out, flags="SA"))
+        out_if.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        in_if.get_capture(1)
+
+        # ACK packet in->out
+        p = (Ether(src=in_if.remote_mac, dst=in_if.local_mac) /
+             IP(src=in_if.remote_ip4, dst=out_if.remote_ip4) /
+             TCP(sport=sport, dport=ext_dport, flags="A"))
+        in_if.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        out_if.get_capture(1)
+
+        return tcp_port_out
+
+    def test_lru_cleanup(self):
+        """ LRU cleanup algorithm """
+        tcp_port_out = self.init_tcp_session(self.pg0, self.pg1, 2000, 80)
+        max_translations = 10 * self.translation_buckets
+        pkts = []
+        for i in range(0, max_translations - 1):
+            p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
+                 IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4, ttl=64) /
+                 UDP(sport=7000+i, dport=80))
+            pkts.append(p)
+
+        self.pg0.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        self.pg1.get_capture(len(pkts))
+        self.sleep(1.5, "wait for timeouts")
+
+        pkts = []
+        for i in range(0, max_translations - 1):
+            p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
+                 IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4, ttl=64) /
+                 ICMP(id=8000+i, type='echo-request'))
+            pkts.append(p)
+
+        self.pg0.add_stream(pkts)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        self.pg1.get_capture(len(pkts))
+
+
 class TestNAT44Out2InDPO(MethodHolder):
     """ NAT44 Test Cases using out2in DPO """