Start LCP auto-creation

This first preparation moves lcp_itf_phy_add() to lcpng_if_sync.c
and renames it lcp_itf_interface_add_del().

It does all the pre-flight checks to validate that a new device, given
by sw_if_index, can have a LIP created:
- must be a sub-int
- must have a sw_sup_if_index, which itself has a LIP

However, I realize that I cannot create an interface from within an
interface add callback, so I'll have to schedule the child LIP to be
created by a process, after the callback returns.

I'll do that in the next commit.

lcpng_if_sync.c

@@ -447,3 +447,48 @@ lcp_itf_ip6_add_del_interface_addr (ip6_main_t *im, uword opaque,
       close (curr_ns_fd);
     }
 }
+
+static clib_error_t *
+lcp_itf_interface_add_del (vnet_main_t *vnm, u32 sw_if_index, u32 is_create)
+{
+  const vnet_sw_interface_t *sw;
+  const lcp_itf_pair_t *sup_lip;
+  uword is_sub;
+
+  is_sub = vnet_sw_interface_is_sub (vnm, sw_if_index);
+  LCP_ITF_PAIR_DBG ("interface_%s: [%u] sw %U is_sub %u",
+		    is_create ? "add" : "del", sw_if_index,
+		    format_vnet_sw_if_index_name, vnet_get_main (),
+		    sw_if_index, is_sub);
+
+  sw = vnet_get_sw_interface_or_null (vnm, sw_if_index);
+  if (!sw)
+    return NULL;
+  if (!is_sub)
+    return NULL;
+
+  LCP_ITF_PAIR_DBG ("interface_%s: sw %U parent %U", is_create ? "add" : "del",
+		    format_vnet_sw_if_index_name, vnet_get_main (),
+		    sw->sw_if_index, format_vnet_sw_if_index_name,
+		    vnet_get_main (), sw->sup_sw_if_index);
+
+  // If the parent has a LIP and we're in auto-create, create a LIP for this
+  // child
+  sup_lip = lcp_itf_pair_get (lcp_itf_pair_find_by_phy (sw->sup_sw_if_index));
+  if (!sup_lip)
+    return NULL;
+
+  LCP_ITF_PAIR_INFO (
+    "interface_%s: %U has parent %U, enqueueing creation of LCP",
+    is_create ? "add" : "del", format_vnet_sw_if_index_name, vnet_get_main (),
+    sw->sw_if_index, format_lcp_itf_pair, sup_lip);
+
+  // We cannot create the interface here, because the previous interface for
+  // which this is a callback hasn't returned yet.
+  // lcp_itf_pair_create(sw->sw_if_index, (u8 *)"foo", LCP_ITF_HOST_TAP,
+  // sup_lip->lip_namespace, NULL);
+
+  return NULL;
+}
+
+VNET_SW_INTERFACE_ADD_DEL_FUNCTION (lcp_itf_interface_add_del);

lcpng_interface.c

@@ -1075,52 +1075,6 @@ lcp_itf_pair_replace_end (void)
   return (0);
 }
 
-static clib_error_t *
-lcp_itf_phy_add (vnet_main_t *vnm, u32 sw_if_index, u32 is_create)
-{
-  vnet_hw_interface_t *hi;
-  index_t lipi;
-  uword is_sub;
-
-  is_sub = vnet_sw_interface_is_sub (vnm, sw_if_index);
-  LCP_ITF_PAIR_INFO ("phy_%s: phy:%U is_sub:%u", is_create?"add":"del",
-		     format_vnet_sw_if_index_name, vnet_get_main (), sw_if_index,
-		     is_sub);
-  if (is_sub) {
-    vnet_sw_interface_t *si;
-    si = vnet_get_sw_interface_or_null (vnm, sw_if_index);
-    LCP_ITF_PAIR_INFO ("phy_%s: si:%U parent:%U", is_create?"add":"del",
-		     format_vnet_sw_if_index_name, vnet_get_main (), si->sw_if_index,
-		     format_vnet_sw_if_index_name, vnet_get_main (), si->sup_sw_if_index
-		     );
-  }
-
-  hi = vnet_get_hw_interface_or_null (vnm, sw_if_index);
-  if (hi) {
-    LCP_ITF_PAIR_INFO ("phy_%s: hi:%U is_sub:%u", is_create?"add":"del",
-		     format_vnet_sw_if_index_name, vnet_get_main (), hi->sw_if_index,
-		     is_sub);
-  }
-
-  lipi = lcp_itf_pair_find_by_phy (sw_if_index);
-  if (lipi != INDEX_INVALID) {
-    lcp_itf_pair_t *lip;
-    vnet_sw_interface_t *si;
-
-    lip = lcp_itf_pair_get (lipi);
-    si = vnet_get_sw_interface_or_null (vnm, lip->lip_host_sw_if_index);
-    if (!si) {
-      LCP_ITF_PAIR_INFO ("phy_%s: si:%U is_sub:%u", is_create?"add":"del",
-		     format_vnet_sw_if_index_name, vnet_get_main (), si->sw_if_index,
-		     is_sub);
-    }
-  }
-
-  return NULL;
-}
-
-VNET_SW_INTERFACE_ADD_DEL_FUNCTION (lcp_itf_phy_add);
-
 static clib_error_t *
 lcp_itf_pair_init (vlib_main_t *vm)
 {