NAT44: improve expired sessions reuse (VPP-1503)

Change-Id: Iab506f127136c94a641df31ded108016de26260b
Signed-off-by: Matus Fabian <matfabia@cisco.com>
diff --git a/test/test_nat.py b/test/test_nat.py
index 524301f..cf5cc63 100644
--- a/test/test_nat.py
+++ b/test/test_nat.py
@@ -5658,7 +5658,7 @@
 
         pkts = []
         for i in range(0, max_sessions):
-            src = "10.10.%u.%u" % ((i & 0xFF00) >> 8, i & 0xFF)
+            src = "10.11.%u.%u" % ((i & 0xFF00) >> 8, i & 0xFF)
             p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
                  IP(src=src, dst=self.pg1.remote_ip4) /
                  ICMP(id=1026, type='echo-request'))
@@ -5683,8 +5683,6 @@
                                                   is_inside=0)
         self.vapi.nat_set_timeouts(tcp_transitory=5)
 
-        nat44_config = self.vapi.nat_show_config()
-
         self.initiate_tcp_session(self.pg0, self.pg1)
         p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
              IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
@@ -5695,18 +5693,6 @@
         self.pg_start()
         self.pg1.get_capture(1)
 
-        pkts_num = nat44_config.max_translations_per_user - 1
-        pkts = []
-        for i in range(0, pkts_num):
-            p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
-                 IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
-                 UDP(sport=1025 + i, dport=53))
-            pkts.append(p)
-        self.pg0.add_stream(pkts)
-        self.pg_enable_capture(self.pg_interfaces)
-        self.pg_start()
-        self.pg1.get_capture(pkts_num)
-
         sleep(6)
 
         p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
@@ -5722,8 +5708,7 @@
         users = self.vapi.nat44_user_dump()
         self.assertEqual(len(users), 1)
         self.assertEqual(users[0].ip_address, self.pg0.remote_ip4n)
-        self.assertEqual(users[0].nsessions,
-                         nat44_config.max_translations_per_user)
+        self.assertEqual(users[0].nsessions, 1)
 
     @unittest.skipUnless(running_extended_tests(), "part of extended tests")
     def test_session_limit_per_user(self):