NAT44: asymmetrical load balancing static mapping rule (VPP-1132)

Add option to NAT44 load balancing static mapping API/CLI to make rule asymmetrical (rule match only in out2in direction).

Change-Id: I325ecef5591e4bf44ce4469a24d44fe56c3bb2e9
Signed-off-by: Matus Fabian <matfabia@cisco.com>

5 files changed, 38 insertions, 22 deletions

diff --git a/src/plugins/nat/in2out.c b/src/plugins/nat/in2out.c
index 5f2f43f7f81..0b87ba47812 100755
--- a/src/plugins/nat/in2out.c
+++ b/src/plugins/nat/in2out.c
@@ -1467,7 +1467,7 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
                     {
                       s0 = snat_in2out_lb(sm, b0, ip0, rx_fib_index0,
                                           thread_index, now, vm, node);
-                      if (!s0)
+                      if (!s0 && !sm->forwarding_enabled)
                         next0 = SNAT_IN2OUT_NEXT_DROP;
                       goto trace00;
                     }
@@ -1646,7 +1646,7 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
                     {
                       s1 = snat_in2out_lb(sm, b1, ip1, rx_fib_index1,
                                           thread_index, now, vm, node);
-                      if (!s1)
+                      if (!s1 && !sm->forwarding_enabled)
                         next1 = SNAT_IN2OUT_NEXT_DROP;
                       goto trace01;
                     }
@@ -1858,7 +1858,7 @@ snat_in2out_node_fn_inline (vlib_main_t * vm,
                     {
                       s0 = snat_in2out_lb(sm, b0, ip0, rx_fib_index0,
                                           thread_index, now, vm, node);
-                      if (!s0)
+                      if (!s0 && !sm->forwarding_enabled)
                         next0 = SNAT_IN2OUT_NEXT_DROP;
                       goto trace0;
                     }
diff --git a/src/plugins/nat/nat.api b/src/plugins/nat/nat.api
index 6ebe4e37933..78f34509b69 100644
--- a/src/plugins/nat/nat.api
+++ b/src/plugins/nat/nat.api
@@ -13,7 +13,7 @@
  * limitations under the License.
  */
 
-vl_api_version 2.1.0
+vl_api_version 2.2.0
 
 /**
  * @file nat.api
@@ -567,6 +567,7 @@ autoreply manual_endian define nat44_add_del_lb_static_mapping {
   u8 protocol;
   u32 vrf_id;
   u8 twice_nat;
+  u8 out2in_only;
   u8 local_num;
   vl_api_nat44_lb_addr_port_t locals[local_num];
 };
@@ -583,6 +584,7 @@ manual_endian define nat44_lb_static_mapping_details {
   u8 protocol;
   u32 vrf_id;
   u8 twice_nat;
+  u8 out2in_only;
   u8 local_num;
   vl_api_nat44_lb_addr_port_t locals[local_num];
 };
diff --git a/src/plugins/nat/nat.c b/src/plugins/nat/nat.c
index 90515acc5b6..99c5f63cf12 100644
--- a/src/plugins/nat/nat.c
+++ b/src/plugins/nat/nat.c
@@ -973,7 +973,7 @@ int snat_add_static_mapping(ip4_address_t l_addr, ip4_address_t e_addr,
 int nat44_add_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
                                      snat_protocol_t proto, u32 vrf_id,
                                      nat44_lb_addr_port_t *locals, u8 is_add,
-                                     u8 twice_nat)
+                                     u8 twice_nat, u8 out2in_only)
 {
   snat_main_t * sm = &snat_main;
   snat_static_mapping_t *m;
@@ -1014,7 +1014,7 @@ int nat44_add_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
 
       /* Find external address in allocated addresses and reserve port for
          address and port pair mapping when dynamic translations enabled */
-      if (!sm->static_mapping_only)
+      if (!(sm->static_mapping_only || out2in_only))
         {
           for (i = 0; i < vec_len (sm->addresses); i++)
             {
@@ -1058,6 +1058,7 @@ int nat44_add_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
       m->external_port = e_port;
       m->proto = proto;
       m->twice_nat = twice_nat;
+      m->out2in_only = out2in_only;
 
       m_key.addr = m->external_addr;
       m_key.port = m->external_port;
@@ -1095,10 +1096,13 @@ int nat44_add_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
       for (i = 0; i < vec_len (locals); i++)
         {
           m_key.addr = locals[i].addr;
-          m_key.port = locals[i].port;
-          kv.key = m_key.as_u64;
-          kv.value = m - sm->static_mappings;
-          clib_bihash_add_del_8_8(&sm->static_mapping_by_local, &kv, 1);
+          if (!out2in_only)
+            {
+              m_key.port = locals[i].port;
+              kv.key = m_key.as_u64;
+              kv.value = m - sm->static_mappings;
+              clib_bihash_add_del_8_8(&sm->static_mapping_by_local, &kv, 1);
+            }
           locals[i].prefix = (i == 0) ? locals[i].probability :\
             (locals[i - 1].prefix + locals[i].probability);
           vec_add1 (m->locals, locals[i]);
@@ -1121,7 +1125,7 @@ int nat44_add_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
       fib_table_unlock (m->fib_index, FIB_PROTOCOL_IP4, FIB_SOURCE_PLUGIN_HI);
 
       /* Free external address port */
-      if (!sm->static_mapping_only)
+      if (!(sm->static_mapping_only || out2in_only))
         {
           for (i = 0; i < vec_len (sm->addresses); i++)
             {
@@ -1173,13 +1177,16 @@ int nat44_add_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
       vec_foreach (local, m->locals)
         {
           m_key.addr = local->addr;
-          m_key.port = local->port;
-          m_key.fib_index = m->fib_index;
-          kv.key = m_key.as_u64;
-          if (clib_bihash_add_del_8_8(&sm->static_mapping_by_local, &kv, 0))
+          if (!out2in_only)
             {
-              clib_warning ("static_mapping_by_local key del failed");
-              return VNET_API_ERROR_UNSPECIFIED;
+              m_key.port = local->port;
+              m_key.fib_index = m->fib_index;
+              kv.key = m_key.as_u64;
+              if (clib_bihash_add_del_8_8(&sm->static_mapping_by_local, &kv, 0))
+                {
+                  clib_warning ("static_mapping_by_local key del failed");
+                  return VNET_API_ERROR_UNSPECIFIED;
+                }
             }
 
           m_key.port = clib_host_to_net_u16 (local->port);
@@ -2509,6 +2516,7 @@ add_lb_static_mapping_command_fn (vlib_main_t * vm,
   u8 proto_set = 0;
   nat44_lb_addr_port_t *locals = 0, local;
   u8 twice_nat = 0;
+  u8 out2in_only = 0;
 
   /* Get a line of input. */
   if (!unformat_user (input, unformat_line_input, line_input))
@@ -2535,6 +2543,8 @@ add_lb_static_mapping_command_fn (vlib_main_t * vm,
         proto_set = 1;
       else if (unformat (line_input, "twice-nat"))
         twice_nat = 1;
+      else if (unformat (line_input, "out2in-only"))
+        out2in_only = 1;
       else if (unformat (line_input, "del"))
         is_add = 0;
       else
@@ -2558,7 +2568,7 @@ add_lb_static_mapping_command_fn (vlib_main_t * vm,
     }
 
   rv = nat44_add_del_lb_static_mapping (e_addr, (u16) e_port, proto, vrf_id,
-                                        locals, is_add, twice_nat);
+                                        locals, is_add, twice_nat, out2in_only);
 
   switch (rv)
     {
@@ -2591,7 +2601,7 @@ VLIB_CLI_COMMAND (add_lb_static_mapping_command, static) = {
   .short_help =
     "nat44 add load-balancing static mapping protocol tcp|udp "
     "external <addr>:<port> local <addr>:<port> probability <n> [twice-nat] "
-    "[vrf <table-id>] [del]",
+    "[vrf <table-id>] [out2in-only] [del]",
 };
 
 static clib_error_t *
diff --git a/src/plugins/nat/nat.h b/src/plugins/nat/nat.h
index 614668d8421..ff7888a9128 100644
--- a/src/plugins/nat/nat.h
+++ b/src/plugins/nat/nat.h
@@ -217,6 +217,7 @@ typedef struct {
   u16 external_port;
   u8 addr_only;
   u8 twice_nat;
+  u8 out2in_only;
   u32 vrf_id;
   u32 fib_index;
   snat_protocol_t proto;
@@ -557,7 +558,7 @@ u8 * format_snat_protocol(u8 * s, va_list * args);
 int nat44_add_del_lb_static_mapping (ip4_address_t e_addr, u16 e_port,
                                      snat_protocol_t proto, u32 vrf_id,
                                      nat44_lb_addr_port_t *locals, u8 is_add,
-                                     u8 twice_nat);
+                                     u8 twice_nat, u8 out2in_only);
 int nat44_del_session (snat_main_t *sm, ip4_address_t *addr, u16 port,
                        snat_protocol_t proto, u32 vrf_id, int is_in);
 void nat_free_session_data (snat_main_t * sm, snat_session_t * s,
diff --git a/src/plugins/nat/nat_api.c b/src/plugins/nat/nat_api.c
index d9f8bbd41be..dc9fc5d9a6d 100644
--- a/src/plugins/nat/nat_api.c
+++ b/src/plugins/nat/nat_api.c
@@ -1238,7 +1238,8 @@ static void
     nat44_add_del_lb_static_mapping (e_addr,
 				     clib_net_to_host_u16 (mp->external_port),
 				     proto, clib_net_to_host_u32 (mp->vrf_id),
-				     locals, mp->is_add, mp->twice_nat);
+				     locals, mp->is_add, mp->twice_nat,
+				     mp->out2in_only);
 
   vec_free (locals);
 
@@ -1251,7 +1252,8 @@ static void *vl_api_nat44_add_del_lb_static_mapping_t_print
   u8 *s;
 
   s = format (0, "SCRIPT: nat44_add_del_lb_static_mapping ");
-  s = format (s, "is_add %d twice_nat %d", mp->is_add, mp->twice_nat);
+  s = format (s, "is_add %d twice_nat %d out2in_only ",
+	      mp->is_add, mp->twice_nat, mp->out2in_only);
 
   FINISH;
 }
@@ -1278,6 +1280,7 @@ send_nat44_lb_static_mapping_details (snat_static_mapping_t * m,
   rmp->vrf_id = ntohl (m->vrf_id);
   rmp->context = context;
   rmp->twice_nat = m->twice_nat;
+  rmp->out2in_only = m->out2in_only;
 
   locals = (vl_api_nat44_lb_addr_port_t *) rmp->locals;
   vec_foreach (ap, m->locals)