ip: add VNET_IP_TABLE_ADD_DEL_FUNCTION

vrf table may be dynamically added or deleted. When the table is deleted,
clients who use the corresponding vrf table may need a callback to
do the clean up. The mechanism added here is cloned from
VNET_SW_INTERFACE_ADD_DEL_FUNCTION.

Type: improvement

Signed-off-by: Steven Luong <sluong@cisco.com>
Change-Id: I08635c715cd7361a6c359b90890dd3545b0da94c

4 files changed, 137 insertions, 0 deletions

diff --git a/src/vnet/CMakeLists.txt b/src/vnet/CMakeLists.txt
index e4182186e60..7757301c73a 100644
--- a/src/vnet/CMakeLists.txt
+++ b/src/vnet/CMakeLists.txt
@@ -489,6 +489,7 @@ list(APPEND VNET_HEADERS
   ip/ip6_hop_by_hop_packet.h
   ip/ip6_packet.h
   ip/ip.h
+  ip/ip_table.h
   ip/ip_interface.h
   ip/ip_packet.h
   ip/ip_source_and_port_range_check.h
diff --git a/src/vnet/ip/ip_api.c b/src/vnet/ip/ip_api.c
index b976eaeaa6b..d26480670b3 100644
--- a/src/vnet/ip/ip_api.c
+++ b/src/vnet/ip/ip_api.c
@@ -46,6 +46,7 @@
 #include <vnet/ip/reass/ip4_full_reass.h>
 #include <vnet/ip/reass/ip6_sv_reass.h>
 #include <vnet/ip/reass/ip6_full_reass.h>
+#include <vnet/ip/ip_table.h>
 
 #include <vnet/vnet_msg_enum.h>
 
@@ -452,10 +453,37 @@ vl_api_ip_punt_redirect_t_handler (vl_api_ip_punt_redirect_t * mp,
   REPLY_MACRO (VL_API_IP_PUNT_REDIRECT_REPLY);
 }
 
+static clib_error_t *
+call_elf_section_ip_table_callbacks (vnet_main_t * vnm, u32 table_id,
+				     u32 flags,
+				     _vnet_ip_table_function_list_elt_t **
+				     elts)
+{
+  _vnet_ip_table_function_list_elt_t *elt;
+  vnet_ip_table_function_priority_t prio;
+  clib_error_t *error = 0;
+
+  for (prio = VNET_IP_TABLE_FUNC_PRIORITY_LOW;
+       prio <= VNET_IP_TABLE_FUNC_PRIORITY_HIGH; prio++)
+    {
+      elt = elts[prio];
+
+      while (elt)
+	{
+	  error = elt->fp (vnm, table_id, flags);
+	  if (error)
+	    return error;
+	  elt = elt->next_ip_table_function;
+	}
+    }
+  return error;
+}
+
 void
 ip_table_delete (fib_protocol_t fproto, u32 table_id, u8 is_api)
 {
   u32 fib_index, mfib_index;
+  vnet_main_t *vnm = vnet_get_main ();
 
   /*
    * ignore action on the default table - this is always present
@@ -474,6 +502,10 @@ ip_table_delete (fib_protocol_t fproto, u32 table_id, u8 is_api)
       fib_index = fib_table_find (fproto, table_id);
       mfib_index = mfib_table_find (fproto, table_id);
 
+      if ((~0 != fib_index) || (~0 != mfib_index))
+	call_elf_section_ip_table_callbacks (vnm, table_id, 0 /* is_add */ ,
+					     vnm->ip_table_add_del_functions);
+
       if (~0 != fib_index)
 	{
 	  fib_table_unlock (fib_index, fproto,
@@ -635,6 +667,7 @@ ip_table_create (fib_protocol_t fproto,
 		 u32 table_id, u8 is_api, const u8 * name)
 {
   u32 fib_index, mfib_index;
+  vnet_main_t *vnm = vnet_get_main ();
 
   /*
    * ignore action on the default table - this is always present
@@ -667,6 +700,10 @@ ip_table_create (fib_protocol_t fproto,
 						      MFIB_SOURCE_API :
 						      MFIB_SOURCE_CLI), name);
 	}
+
+      if ((~0 == fib_index) || (~0 == mfib_index))
+	call_elf_section_ip_table_callbacks (vnm, table_id, 1 /* is_add */ ,
+					     vnm->ip_table_add_del_functions);
     }
 }
 
diff --git a/src/vnet/ip/ip_table.h b/src/vnet/ip/ip_table.h
new file mode 100644
index 00000000000..1f75c15be26
--- /dev/null
+++ b/src/vnet/ip/ip_table.h
@@ -0,0 +1,95 @@
+/*
+ * Copyright (c) 2020 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef included_ip_table_h
+#define included_ip_table_h
+
+#include <vlib/vlib.h>
+
+/* ip table add delete callback */
+typedef struct _vnet_ip_table_function_list_elt
+{
+  struct _vnet_ip_table_function_list_elt *next_ip_table_function;
+  clib_error_t *(*fp) (struct vnet_main_t * vnm, u32 table_id, u32 flags);
+} _vnet_ip_table_function_list_elt_t;
+
+typedef enum vnet_ip_table_function_priority_t_
+{
+  VNET_IP_TABLE_FUNC_PRIORITY_LOW,
+  VNET_IP_TABLE_FUNC_PRIORITY_HIGH,
+} vnet_ip_table_function_priority_t;
+#define VNET_IP_TABLE_FUNC_N_PRIO ((vnet_ip_table_function_priority_t)VNET_IP_TABLE_FUNC_PRIORITY_HIGH+1)
+
+#ifndef CLIB_MARCH_VARIANT
+#define _VNET_IP_TABLE_FUNCTION_DECL_PRIO(f,tag,p)                    \
+                                                                        \
+static void __vnet_ip_table_function_init_##tag##_##f (void)           \
+    __attribute__((__constructor__)) ;                                  \
+                                                                        \
+static void __vnet_ip_table_function_init_##tag##_##f (void)           \
+{                                                                       \
+ vnet_main_t * vnm = vnet_get_main();                                   \
+ static _vnet_ip_table_function_list_elt_t init_function;              \
+ init_function.next_ip_table_function = vnm->tag##_functions[p];       \
+ vnm->tag##_functions[p] = &init_function;                              \
+ init_function.fp = (void *) &f;                                        \
+}                                                                       \
+static void __vnet_ip_table_function_deinit_##tag##_##f (void)         \
+    __attribute__((__destructor__)) ;                                   \
+                                                                        \
+static void __vnet_ip_table_function_deinit_##tag##_##f (void)         \
+{                                                                       \
+ vnet_main_t * vnm = vnet_get_main();                                   \
+ _vnet_ip_table_function_list_elt_t *next;                             \
+ if (vnm->tag##_functions[p]->fp == f)                                  \
+    {                                                                   \
+      vnm->tag##_functions[p] =                                         \
+        vnm->tag##_functions[p]->next_ip_table_function;               \
+      return;                                                           \
+    }                                                                   \
+  next = vnm->tag##_functions[p];                                       \
+  while (next->next_ip_table_function)                                 \
+    {                                                                   \
+      if (next->next_ip_table_function->fp == f)                       \
+        {                                                               \
+          next->next_ip_table_function =                               \
+            next->next_ip_table_function->next_ip_table_function;     \
+          return;                                                       \
+        }                                                               \
+      next = next->next_ip_table_function;                             \
+    }                                                                   \
+}
+#else
+/* create unused pointer to silence compiler warnings and get whole
+   function optimized out */
+#define _VNET_IP_TABLE_FUNCTION_DECL_PRIO(f,tag,p)                    \
+static __clib_unused void * __clib_unused_##f = f;
+#endif
+
+#define _VNET_IP_TABLE_FUNCTION_DECL(f,tag)                            \
+  _VNET_IP_TABLE_FUNCTION_DECL_PRIO(f,tag,VNET_ITF_FUNC_PRIORITY_LOW)
+
+#define VNET_IP_TABLE_ADD_DEL_FUNCTION(f)			\
+  _VNET_IP_TABLE_FUNCTION_DECL(f,ip_table_add_del)
+
+#endif /* included_ip_table_h */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */
diff --git a/src/vnet/vnet.h b/src/vnet/vnet.h
index 3b20f71917b..42f7333feb5 100644
--- a/src/vnet/vnet.h
+++ b/src/vnet/vnet.h
@@ -47,6 +47,7 @@
 #include <vnet/config.h>
 #include <vnet/interface.h>
 #include <vnet/api_errno.h>
+#include <vnet/ip/ip_table.h>
 
 typedef struct vnet_main_t
 {
@@ -71,6 +72,9 @@ typedef struct vnet_main_t
 
   uword *interface_tag_by_sw_if_index;
 
+    _vnet_ip_table_function_list_elt_t
+    * ip_table_add_del_functions[VNET_ITF_FUNC_N_PRIO];
+
   /*
    * Last "api" error, preserved so we can issue reasonable diagnostics
    * at or near the top of the food chain