nat: NAT44 ED api fix and improvement

Backward compatibility fix returns erroneous behavior that lets user
add internally unused inside interface for the purpose
of complying with the old add/dump/details API behavior.
Change introduced in https://gerrit.fd.io/r/c/vpp/+/32951 removed
extra inside interface that wasn't required or any how used by the
output feature. This patch also changed outside interface flags to
inside & outside. This fix returns the old behavior by imitating
the old behavior through dummy registratoin data.

Added new API calls nat44_ed_add_del_output_interface
and nat44_ed_output_interface_get/details as a
replacement of old API's. New API introduces
simplified and cleaner way of configuring outside
feature without requirement of config flags.

Type: improvement
Signed-off-by: Filip Varga <fivarga@cisco.com>
Change-Id: I7a170f7325727c04da5e2e3ffbe3f02179531284

3 files changed, 178 insertions, 14 deletions

diff --git a/src/plugins/nat/nat44-ed/nat44_ed.api b/src/plugins/nat/nat44-ed/nat44_ed.api
index bff00b809e0..36637b26246 100644
--- a/src/plugins/nat/nat44-ed/nat44_ed.api
+++ b/src/plugins/nat/nat44-ed/nat44_ed.api
@@ -729,6 +729,7 @@ define nat44_interface_details {
     @param sw_if_index - software index of the interface
 */
 autoreply define nat44_interface_add_del_output_feature {
+  option deprecated;
   u32 client_index;
   u32 context;
   bool is_add;
@@ -741,6 +742,7 @@ autoreply define nat44_interface_add_del_output_feature {
     @param context - sender context, to match reply w/ request
 */
 define nat44_interface_output_feature_dump {
+  option deprecated;
   u32 client_index;
   u32 context;
 };
@@ -752,11 +754,51 @@ define nat44_interface_output_feature_dump {
     @param sw_if_index - software index of the interface
 */
 define nat44_interface_output_feature_details {
+  option deprecated;
   u32 context;
   vl_api_nat_config_flags_t flags;
   vl_api_interface_index_t sw_if_index;
 };
 
+/** \brief add/del NAT output interface (postrouting
+           in2out translation)
+    @param client_index - opaque cookie to identify the sender
+    @param context - sender context, to match reply w/ request
+    @param is_add - true if add, false if delete
+    @param sw_if_index - software index of the interface
+*/
+autoendian autoreply define nat44_ed_add_del_output_interface {
+  u32 client_index;
+  u32 context;
+  bool is_add;
+  vl_api_interface_index_t sw_if_index;
+};
+
+service {
+  rpc nat44_ed_output_interface_get returns nat44_ed_output_interface_get_reply
+    stream nat44_ed_output_interface_details;
+};
+
+define nat44_ed_output_interface_get
+{
+  u32 client_index;
+  u32 context;
+  u32 cursor;
+};
+
+define nat44_ed_output_interface_get_reply
+{
+  u32 context;
+  i32 retval;
+  u32 cursor;
+};
+
+define nat44_ed_output_interface_details
+{
+  u32 context;
+  vl_api_interface_index_t sw_if_index;
+};
+
 /** \brief Add/delete NAT44 static mapping
     @param client_index - opaque cookie to identify the sender
     @param context - sender context, to match reply w/ request
diff --git a/src/plugins/nat/nat44-ed/nat44_ed.h b/src/plugins/nat/nat44-ed/nat44_ed.h
index f8cd9a06bea..e2f5810f9b0 100644
--- a/src/plugins/nat/nat44-ed/nat44_ed.h
+++ b/src/plugins/nat/nat44-ed/nat44_ed.h
@@ -540,6 +540,8 @@ typedef struct snat_main_s
   /* Interface pool */
   snat_interface_t *interfaces;
   snat_interface_t *output_feature_interfaces;
+  // broken api backward compatibility
+  snat_interface_t *output_feature_dummy_interfaces;
 
   /* Vector of outside addresses */
   snat_address_t *addresses;
diff --git a/src/plugins/nat/nat44-ed/nat44_ed_api.c b/src/plugins/nat/nat44-ed/nat44_ed_api.c
index d4de4823025..ad00d11052b 100644
--- a/src/plugins/nat/nat44-ed/nat44_ed_api.c
+++ b/src/plugins/nat/nat44-ed/nat44_ed_api.c
@@ -426,9 +426,50 @@ vl_api_nat44_interface_dump_t_handler (vl_api_nat44_interface_dump_t * mp)
     return;
 
   pool_foreach (i, sm->interfaces)
-   {
-    send_nat44_interface_details(i, reg, mp->context);
-  }
+    {
+      send_nat44_interface_details (i, reg, mp->context);
+    }
+}
+
+static_always_inline int
+add_del_dummy_output_interface (u32 sw_if_index, u8 is_inside, u8 is_add)
+{
+  snat_main_t *sm = &snat_main;
+  snat_interface_t *i;
+  int rv = 1;
+
+  pool_foreach (i, sm->output_feature_dummy_interfaces)
+    {
+      if (i->sw_if_index == sw_if_index)
+	{
+	  if (!is_add)
+	    {
+	      pool_put (sm->output_feature_dummy_interfaces, i);
+	      rv = 0;
+	    }
+	  goto done;
+	}
+    }
+
+  if (is_add)
+    {
+      pool_get (sm->output_feature_dummy_interfaces, i);
+      i->sw_if_index = sw_if_index;
+
+      if (is_inside)
+	{
+	  i->flags |= NAT_INTERFACE_FLAG_IS_INSIDE;
+	}
+      else
+	{
+	  i->flags |= NAT_INTERFACE_FLAG_IS_OUTSIDE;
+	}
+
+      rv = 0;
+    }
+
+done:
+  return rv;
 }
 
 static void
@@ -444,13 +485,20 @@ static void
 
   sw_if_index = ntohl (mp->sw_if_index);
 
-  if (mp->is_add)
-    {
-      rv = nat44_ed_add_output_interface (sw_if_index);
-    }
-  else
+  // register all interfaces in the dummy structure
+  rv = add_del_dummy_output_interface (
+    sw_if_index, mp->flags & NAT_API_IS_INSIDE, mp->is_add);
+
+  if (!(mp->flags & NAT_API_IS_INSIDE))
     {
-      rv = nat44_ed_del_output_interface (sw_if_index);
+      if (mp->is_add)
+	{
+	  rv = nat44_ed_add_output_interface (sw_if_index);
+	}
+      else
+	{
+	  rv = nat44_ed_del_output_interface (sw_if_index);
+	}
     }
 
   BAD_SW_IF_INDEX_LABEL;
@@ -473,7 +521,9 @@ send_nat44_interface_output_feature_details (snat_interface_t * i,
   rmp->context = context;
 
   if (nat44_ed_is_interface_inside (i))
-    rmp->flags |= NAT_API_IS_INSIDE;
+    {
+      rmp->flags |= NAT_API_IS_INSIDE;
+    }
 
   vl_api_send_msg (reg, (u8 *) rmp);
 }
@@ -490,10 +540,80 @@ static void
   if (!reg)
     return;
 
-  pool_foreach (i, sm->output_feature_interfaces)
-   {
-     send_nat44_interface_output_feature_details (i, reg, mp->context);
-  }
+  pool_foreach (i, sm->output_feature_dummy_interfaces)
+    {
+      send_nat44_interface_output_feature_details (i, reg, mp->context);
+    }
+}
+
+static void
+vl_api_nat44_ed_add_del_output_interface_t_handler (
+  vl_api_nat44_ed_add_del_output_interface_t *mp)
+{
+  vl_api_nat44_ed_add_del_output_interface_reply_t *rmp;
+  snat_main_t *sm = &snat_main;
+  u32 sw_if_index;
+  int rv = 0;
+
+  VALIDATE_SW_IF_INDEX (mp);
+
+  sw_if_index = ntohl (mp->sw_if_index);
+
+  if (mp->is_add)
+    {
+      rv = nat44_ed_add_output_interface (sw_if_index);
+    }
+  else
+    {
+      rv = nat44_ed_del_output_interface (sw_if_index);
+    }
+
+  BAD_SW_IF_INDEX_LABEL;
+  REPLY_MACRO (VL_API_NAT44_ED_ADD_DEL_OUTPUT_INTERFACE_REPLY);
+}
+
+#define vl_endianfun
+#include <nat/nat44-ed/nat44_ed.api.h>
+#undef vl_endianfun
+static void
+send_nat44_ed_output_interface_details (u32 index, vl_api_registration_t *rp,
+					u32 context)
+{
+  snat_main_t *sm = &snat_main;
+  vl_api_nat44_ed_output_interface_details_t *rmp;
+  snat_interface_t *i =
+    pool_elt_at_index (sm->output_feature_interfaces, index);
+
+  /* Make sure every field is initiated (or don't skip the clib_memset()) */
+  REPLY_MACRO_DETAILS4 (
+    VL_API_NAT44_ED_OUTPUT_INTERFACE_DETAILS, rp, context, ({
+      rmp->sw_if_index = i->sw_if_index;
+
+      /* Endian hack until apigen registers _details
+       * endian functions */
+      vl_api_nat44_ed_output_interface_details_t_endian (rmp);
+      rmp->_vl_msg_id = htons (rmp->_vl_msg_id);
+      rmp->context = htonl (rmp->context);
+    }));
+}
+
+static void
+vl_api_nat44_ed_output_interface_get_t_handler (
+  vl_api_nat44_ed_output_interface_get_t *mp)
+{
+  vl_api_nat44_ed_output_interface_get_reply_t *rmp;
+  snat_main_t *sm = &snat_main;
+  i32 rv = 0;
+
+  if (pool_elts (sm->output_feature_interfaces) == 0)
+    {
+      REPLY_MACRO (VL_API_NAT44_ED_OUTPUT_INTERFACE_GET_REPLY);
+      return;
+    }
+
+  REPLY_AND_DETAILS_MACRO (
+    VL_API_NAT44_ED_OUTPUT_INTERFACE_GET_REPLY, sm->output_feature_interfaces,
+    ({ send_nat44_ed_output_interface_details (cursor, rp, mp->context); }));
 }
 
 static void