NAT44: in2out output feature skip translation for already translated packets (VPP-1156)

Change-Id: I5395245c9e49f741a949ada1f725c34f9379c249
Signed-off-by: Matus Fabian <matfabia@cisco.com>

3 files changed, 173 insertions, 15 deletions

diff --git a/src/plugins/nat/in2out.c b/src/plugins/nat/in2out.c
index a453328c38f..003b1ad3858 100755
--- a/src/plugins/nat/in2out.c
+++ b/src/plugins/nat/in2out.c
@@ -252,6 +252,27 @@ snat_not_translate (snat_main_t * sm, vlib_node_runtime_t *node,
                                  rx_fib_index0);
 }
 
+static inline int
+nat_not_translate_output_feature (snat_main_t * sm, ip4_header_t * ip0,
+                                  u32 proto0, u32 thread_index)
+{
+  udp_header_t * udp0 = ip4_next_header (ip0);
+  snat_session_key_t key0;
+  clib_bihash_kv_8_8_t kv0, value0;
+
+  key0.addr = ip0->src_address;
+  key0.port = udp0->src_port;
+  key0.protocol = proto0;
+  key0.fib_index = sm->outside_fib_index;
+  kv0.key = key0.as_u64;
+
+  if (!clib_bihash_search_8_8 (&sm->per_thread_data[thread_index].out2in, &kv0,
+                              &value0))
+    return 1;
+
+  return 0;
+}
+
 static u32 slow_path (snat_main_t *sm, vlib_buffer_t *b0,
                       ip4_header_t * ip0,
                       u32 rx_fib_index0,
@@ -497,12 +518,23 @@ u32 icmp_match_in2out_slow(snat_main_t *sm, vlib_node_runtime_t *node,
   if (clib_bihash_search_8_8 (&sm->per_thread_data[thread_index].in2out, &kv0,
                               &value0))
     {
-      if (PREDICT_FALSE(snat_not_translate(sm, node, sw_if_index0, ip0,
-          IP_PROTOCOL_ICMP, rx_fib_index0, thread_index) &&
-          vnet_buffer(b0)->sw_if_index[VLIB_TX] == ~0))
+      if (vnet_buffer(b0)->sw_if_index[VLIB_TX] != ~0)
         {
-          dont_translate = 1;
-          goto out;
+          if (PREDICT_FALSE(nat_not_translate_output_feature(sm,
+              ip0, IP_PROTOCOL_ICMP, thread_index)))
+            {
+              dont_translate = 1;
+              goto out;
+            }
+        }
+      else
+        {
+          if (PREDICT_FALSE(snat_not_translate(sm, node, sw_if_index0,
+              ip0, IP_PROTOCOL_ICMP, rx_fib_index0, thread_index)))
+            {
+              dont_translate = 1;
+              goto out;
+            }
         }
 
       if (PREDICT_FALSE(icmp_is_error_message (icmp0)))
@@ -1517,9 +1549,18 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
             {
               if (is_slow_path)
                 {
-                  if (PREDICT_FALSE(snat_not_translate(sm, node, sw_if_index0,
-                      ip0, proto0, rx_fib_index0, thread_index)) && !is_output_feature)
-                    goto trace00;
+                  if (is_output_feature)
+                    {
+                      if (PREDICT_FALSE(nat_not_translate_output_feature(sm,
+                          ip0, proto0, thread_index)))
+                        goto trace00;
+                    }
+                  else
+                    {
+                      if (PREDICT_FALSE(snat_not_translate(sm, node, sw_if_index0,
+                          ip0, proto0, rx_fib_index0, thread_index)))
+                        goto trace00;
+                    }
 
                   next0 = slow_path (sm, b0, ip0, rx_fib_index0, &key0,
                                      &s0, node, next0, thread_index);
@@ -1696,9 +1737,18 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
             {
               if (is_slow_path)
                 {
-                  if (PREDICT_FALSE(snat_not_translate(sm, node, sw_if_index1,
-                      ip1, proto1, rx_fib_index1, thread_index)) && !is_output_feature)
-                    goto trace01;
+                  if (is_output_feature)
+                    {
+                      if (PREDICT_FALSE(nat_not_translate_output_feature(sm,
+                          ip1, proto1, thread_index)))
+                        goto trace00;
+                    }
+                  else
+                    {
+                      if (PREDICT_FALSE(snat_not_translate(sm, node, sw_if_index1,
+                          ip1, proto1, rx_fib_index1, thread_index)))
+                        goto trace01;
+                    }
 
                   next1 = slow_path (sm, b1, ip1, rx_fib_index1, &key1,
                                      &s1, node, next1, thread_index);
@@ -1907,9 +1957,18 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
             {
               if (is_slow_path)
                 {
-                  if (PREDICT_FALSE(snat_not_translate(sm, node, sw_if_index0,
-                      ip0, proto0, rx_fib_index0, thread_index)) && !is_output_feature)
-                    goto trace0;
+                  if (is_output_feature)
+                    {
+                      if (PREDICT_FALSE(nat_not_translate_output_feature(sm,
+                          ip0, proto0, thread_index)))
+                        goto trace0;
+                    }
+                  else
+                    {
+                      if (PREDICT_FALSE(snat_not_translate(sm, node, sw_if_index0,
+                          ip0, proto0, rx_fib_index0, thread_index)))
+                        goto trace0;
+                    }
 
                   next0 = slow_path (sm, b0, ip0, rx_fib_index0, &key0,
                                      &s0, node, next0, thread_index);
diff --git a/src/plugins/nat/nat.c b/src/plugins/nat/nat.c
index 38caae43376..ef740d9d12b 100644
--- a/src/plugins/nat/nat.c
+++ b/src/plugins/nat/nat.c
@@ -774,7 +774,7 @@ int snat_add_static_mapping(ip4_address_t l_addr, ip4_address_t e_addr,
                 }
             }
           /* External address must be allocated */
-          if (!a)
+          if (!a && (l_addr.as_u32 != e_addr.as_u32))
             return VNET_API_ERROR_NO_SUCH_ENTRY;
         }
 
diff --git a/test/test_nat.py b/test/test_nat.py
index 34726ea41b2..e3b44859f61 100644
--- a/test/test_nat.py
+++ b/test/test_nat.py
@@ -3270,6 +3270,105 @@ class TestNAT44(MethodHolder):
             self.logger.error(ppp("Unexpected or invalid packet:", p))
             raise
 
+    def test_output_feature_and_service(self):
+        """ NAT44 interface output feature and services """
+        external_addr = '1.2.3.4'
+        external_port = 80
+        local_port = 8080
+
+        self.vapi.nat44_forwarding_enable_disable(1)
+        self.nat44_add_address(self.nat_addr)
+        self.nat44_add_static_mapping(self.pg0.remote_ip4, external_addr,
+                                      local_port, external_port,
+                                      proto=IP_PROTOS.tcp, out2in_only=1)
+        self.vapi.nat44_interface_add_del_feature(self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_output_feature(self.pg1.sw_if_index,
+                                                         is_inside=0)
+
+        # from client to service
+        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
+             IP(src=self.pg1.remote_ip4, dst=external_addr) /
+             TCP(sport=12345, dport=external_port))
+        self.pg1.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg0.get_capture(1)
+        p = capture[0]
+        server = None
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.dst, self.pg0.remote_ip4)
+            self.assertEqual(tcp.dport, local_port)
+            self.check_tcp_checksum(p)
+            self.check_ip_checksum(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
+
+        # from service back to client
+        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=local_port, dport=12345))
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg1.get_capture(1)
+        p = capture[0]
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.src, external_addr)
+            self.assertEqual(tcp.sport, external_port)
+            self.check_tcp_checksum(p)
+            self.check_ip_checksum(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
+
+        # from local network host to external network
+        ext_port = 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=23456, dport=34567))
+        self.pg0.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg1.get_capture(1)
+        p = capture[0]
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.src, self.nat_addr)
+            self.assertNotEqual(tcp.sport, 23456)
+            ext_port = tcp.sport
+            self.check_tcp_checksum(p)
+            self.check_ip_checksum(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
+
+        # from external network back to local network host
+        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
+             IP(src=self.pg1.remote_ip4, dst=self.nat_addr) /
+             TCP(sport=34567, dport=ext_port))
+        self.pg1.add_stream(p)
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+        capture = self.pg0.get_capture(1)
+        p = capture[0]
+        server = None
+        try:
+            ip = p[IP]
+            tcp = p[TCP]
+            self.assertEqual(ip.dst, self.pg0.remote_ip4)
+            self.assertEqual(tcp.dport, 23456)
+            self.check_tcp_checksum(p)
+            self.check_ip_checksum(p)
+        except:
+            self.logger.error(ppp("Unexpected or invalid packet:", p))
+            raise
+
     def test_one_armed_nat44(self):
         """ One armed NAT44 """
         remote_host = self.pg9.remote_hosts[0]