nat: static mappings in flow hash

Put static mappings in flow hash, drop existing hash tables used for
static mappings. Drop refcount variables and use hash table as a single
point of truth. Allow creating a static mapping conflicting with dynamic
mapping, which will take precedence after dynamic mapping is freed, so
that the existing flow can finish transferring data.

Type: fix
Signed-off-by: Klement Sekera <ksekera@cisco.com>
Change-Id: Ieeba691d83a83887d0a0baccd5f3832f66126096

1 files changed, 229 insertions, 0 deletions

diff --git a/test/test_nat44_ed_output.py b/test/test_nat44_ed_output.py
new file mode 100644
index 00000000000..ea5c14e7064
--- /dev/null
+++ b/test/test_nat44_ed_output.py
@@ -0,0 +1,229 @@
+#!/usr/bin/env python3
+"""NAT44 ED output-feature tests"""
+
+import random
+import unittest
+from scapy.layers.inet import ICMP, Ether, IP, TCP
+from scapy.packet import Raw
+from scapy.data import IP_PROTOS
+from framework import VppTestCase, VppTestRunner
+from vpp_papi import VppEnum
+
+
+def get_nat44_ed_in2out_worker_index(ip, vpp_worker_count):
+    if 0 == vpp_worker_count:
+        return 0
+    numeric = socket.inet_aton(ip)
+    numeric = struct.unpack("!L", numeric)[0]
+    numeric = socket.htonl(numeric)
+    h = numeric + (numeric >> 8) + (numeric >> 16) + (numeric >> 24)
+    return 1 + h % vpp_worker_count
+
+
+class TestNAT44EDOutput(VppTestCase):
+    """ NAT44 ED output feature Test Case """
+    max_sessions = 1024
+
+    @classmethod
+    def setUpClass(cls):
+        super().setUpClass()
+        cls.create_pg_interfaces(range(2))
+        cls.interfaces = list(cls.pg_interfaces)
+
+    @classmethod
+    def tearDownClass(cls):
+        super().tearDownClass()
+
+    def setUp(self):
+        super().setUp()
+        for i in self.interfaces:
+            i.admin_up()
+            i.config_ip4()
+            i.resolve_arp()
+        self.vapi.nat44_ed_plugin_enable_disable(sessions=self.max_sessions,
+                                                 enable=1)
+
+    def tearDown(self):
+        if not self.vpp_dead:
+            self.logger.debug(self.vapi.cli("show nat44 sessions"))
+        super().tearDown()
+        if not self.vpp_dead:
+            for i in self.pg_interfaces:
+                i.unconfig_ip4()
+                i.admin_down()
+            self.vapi.nat44_ed_plugin_enable_disable(enable=0)
+
+    def test_static_dynamic(self):
+        """ Create static mapping which matches existing dynamic mapping """
+
+        old_timeouts = self.vapi.nat_get_timeouts()
+        new_transitory = 2
+        self.vapi.nat_set_timeouts(
+            udp=old_timeouts.udp,
+            tcp_established=old_timeouts.tcp_established,
+            icmp=old_timeouts.icmp,
+            tcp_transitory=new_transitory)
+
+        local_host = self.pg0.remote_ip4
+        remote_host = self.pg1.remote_ip4
+        nat_intf = self.pg1
+        outside_addr = nat_intf.local_ip4
+
+        self.vapi.nat44_add_del_address_range(first_ip_address=outside_addr,
+                                              last_ip_address=outside_addr,
+                                              vrf_id=0xffffffff,
+                                              is_add=1,
+                                              flags=0)
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            is_add=1)
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=VppEnum.vl_api_nat_config_flags_t.NAT_IS_INSIDE, is_add=1)
+        self.vapi.nat44_interface_add_del_output_feature(
+            is_add=1,
+            sw_if_index=self.pg1.sw_if_index)
+
+        thread_index = get_nat44_ed_in2out_worker_index(
+            local_host, self.vpp_worker_count)
+        port_per_thread = int((0xffff-1024) / max(1, self.vpp_worker_count))
+        local_sport = 1024 + random.randint(1, port_per_thread)
+        if self.vpp_worker_count > 0:
+            local_sport += port_per_thread * (thread_index - 1)
+
+        remote_dport = 10000
+
+        pg0 = self.pg0
+        pg1 = self.pg1
+
+        # first setup a dynamic TCP session
+
+        # SYN packet in->out
+        p = (Ether(src=pg0.remote_mac, dst=pg0.local_mac) /
+             IP(src=local_host, dst=remote_host) /
+             TCP(sport=local_sport, dport=remote_dport, flags="S"))
+        p = self.send_and_expect(pg0, [p], pg1)[0]
+
+        self.assertEqual(p[IP].src, outside_addr)
+        self.assertEqual(p[TCP].sport, local_sport)
+        outside_port = p[TCP].sport
+
+        # SYN+ACK packet out->in
+        p = (Ether(src=pg1.remote_mac, dst=pg1.local_mac) /
+             IP(src=remote_host, dst=outside_addr) /
+             TCP(sport=remote_dport, dport=outside_port, flags="SA"))
+        self.send_and_expect(pg1, [p], pg0)
+
+        # ACK packet in->out
+        p = (Ether(src=pg0.remote_mac, dst=pg0.local_mac) /
+             IP(src=local_host, dst=remote_host) /
+             TCP(sport=local_sport, dport=remote_dport, flags="A"))
+        self.send_and_expect(pg0, [p], pg1)
+
+        # now we have a session up, create a conflicting static mapping
+        self.vapi.nat44_add_del_static_mapping(
+            is_add=1,
+            local_ip_address=local_host,
+            external_ip_address=outside_addr,
+            external_sw_if_index=0xffffffff,
+            local_port=local_sport,
+            external_port=outside_port,
+            protocol=IP_PROTOS.tcp,
+            flags=VppEnum.vl_api_nat_config_flags_t.NAT_IS_OUT2IN_ONLY)
+
+        sessions = self.vapi.nat44_user_session_dump(local_host, 0)
+        self.assertEqual(1, len(sessions))
+
+        # now send some more data over existing session - it should pass
+
+        # in->out
+        p = (Ether(src=pg0.remote_mac, dst=pg0.local_mac) /
+             IP(src=local_host, dst=remote_host) /
+             TCP(sport=local_sport, dport=remote_dport) /
+             Raw("zippity zap"))
+        self.send_and_expect(pg0, [p], pg1)
+
+        # out->in
+        p = (Ether(src=pg1.remote_mac, dst=pg1.local_mac) /
+             IP(src=remote_host, dst=outside_addr) /
+             TCP(sport=remote_dport, dport=outside_port) /
+             Raw("flippity flop"))
+        self.send_and_expect(pg1, [p], pg0)
+
+        # now close the session
+
+        # FIN packet in -> out
+        p = (Ether(src=pg0.remote_mac, dst=pg0.local_mac) /
+             IP(src=local_host, dst=remote_host) /
+             TCP(sport=local_sport, dport=remote_dport, flags="FA", seq=100,
+                 ack=300))
+        self.send_and_expect(pg0, [p], pg1)
+
+        # FIN+ACK packet out -> in
+        p = (Ether(src=pg1.remote_mac, dst=pg1.local_mac) /
+             IP(src=remote_host, dst=outside_addr) /
+             TCP(sport=remote_dport, dport=outside_port, flags="FA", seq=300,
+                 ack=101))
+        self.send_and_expect(pg1, [p], pg0)
+
+        # ACK packet in -> out
+        p = (Ether(src=pg0.remote_mac, dst=pg0.local_mac) /
+             IP(src=local_host, dst=remote_host) /
+             TCP(sport=local_sport, dport=remote_dport, flags="A", seq=101,
+                 ack=301))
+        self.send_and_expect(pg0, [p], pg1)
+
+        # session now in transitory timeout
+        # try SYN packet in->out - should be dropped
+        p = (Ether(src=pg0.remote_mac, dst=pg0.local_mac) /
+             IP(src=local_host, dst=remote_host) /
+             TCP(sport=local_sport, dport=remote_dport, flags="S"))
+        pg0.add_stream(p)
+        self.pg_enable_capture()
+        self.pg_start()
+
+        self.sleep(new_transitory, "wait for transitory timeout")
+        pg0.assert_nothing_captured(0)
+
+        # session should still exist
+        sessions = self.vapi.nat44_user_session_dump(pg0.remote_ip4, 0)
+        self.assertEqual(1, len(sessions))
+
+        # send FIN+ACK packet in->out - will cause session to be wiped
+        # but won't create a new session
+        p = (Ether(src=pg0.remote_mac, dst=pg0.local_mac) /
+             IP(src=local_host, dst=remote_host) /
+             TCP(sport=local_sport, dport=remote_dport, flags="FA", seq=300,
+                 ack=101))
+        pg1.add_stream(p)
+        self.pg_enable_capture()
+        self.pg_start()
+        pg0.assert_nothing_captured(0)
+
+        sessions = self.vapi.nat44_user_session_dump(pg0.remote_ip4, 0)
+        self.assertEqual(0, len(sessions))
+
+        # create a new session and make sure the outside port is remapped
+        # SYN packet in->out
+
+        p = (Ether(src=pg0.remote_mac, dst=pg0.local_mac) /
+             IP(src=local_host, dst=remote_host) /
+             TCP(sport=local_sport, dport=remote_dport, flags="S"))
+        p = self.send_and_expect(pg0, [p], pg1)[0]
+
+        self.assertEqual(p[IP].src, outside_addr)
+        self.assertNotEqual(p[TCP].sport, local_sport)
+
+        # make sure static mapping works and creates a new session
+        # SYN packet out->in
+        p = (Ether(src=pg1.remote_mac, dst=pg1.local_mac) /
+             IP(src=remote_host, dst=outside_addr) /
+             TCP(sport=remote_dport, dport=outside_port, flags="S"))
+        self.send_and_expect(pg1, [p], pg0)
+
+        sessions = self.vapi.nat44_user_session_dump(pg0.remote_ip4, 0)
+        self.assertEqual(2, len(sessions))
+
+
+if __name__ == '__main__':
+    unittest.main(testRunner=VppTestRunner)