FIB Interpose Source

The interpose source allows the source/provider to insert/interpose
a DPO in the forwarding chain of the FIB entry ahead of the forwarding
provided by the next best source. For example if the API source (i.e
the 'control plane') has provided an adjacency for forwarding, then
an interpose source (e.g. a monitoring service) couold interpose a
replicatte DPO to copy the traffic to another location AND forward
using the API's adjacency.
To use the interose feature an existing source (i.e FIB_SOURCE_PLUGIN_HI)
cn specifiy as a flag FIB_ENTRY_FLAG_INTERPOSE and provide a DPO to
interpose. One might also consider using interpose in conjunction with
FIB_ENTRY_FLAG_COVER_INHERIT to ensure the interpose object affects
all prefixes in the sub-tree.

Change-Id: I8b2737b985f8f7c08123406d0491881def347b52
Signed-off-by: Neale Ranns <nranns@cisco.com>

1 files changed, 55 insertions, 13 deletions

diff --git a/src/vnet/fib/fib_entry_src.h b/src/vnet/fib/fib_entry_src.h
index 57840d555ee..61740201eb7 100644
--- a/src/vnet/fib/fib_entry_src.h
+++ b/src/vnet/fib/fib_entry_src.h
@@ -173,6 +173,26 @@ typedef const void* (*fib_entry_src_get_data_t)(fib_entry_src_t *src,
                                                 const fib_entry_t *fib_entry);
 
 /**
+ * Contribute forwarding to interpose inthe chain
+ */
+typedef const dpo_id_t* (*fib_entry_src_contribute_interpose_t)(const fib_entry_src_t *src,
+                                                         const fib_entry_t *fib_entry);
+
+/**
+ * The fib entry flags for this source are changing
+ */
+typedef void (*fib_entry_src_flag_change_t)(fib_entry_src_t *src,
+                                            const fib_entry_t *fib_entry,
+                                            fib_entry_flag_t new_flags);
+
+/**
+ * The fib entry flags for this source are changing
+ */
+typedef void (*fib_entry_src_copy_t)(const fib_entry_src_t *orig_src,
+                                     const fib_entry_t *fib_entry,
+                                     fib_entry_src_t *copy_src);
+
+/**
  * Virtual function table each FIB entry source will register
  */
 typedef struct fib_entry_src_vft_t_ {
@@ -193,21 +213,48 @@ typedef struct fib_entry_src_vft_t_ {
     fib_entry_src_fwd_update_t fesv_fwd_update;
     fib_entry_src_get_data_t fesv_get_data;
     fib_entry_src_set_data_t fesv_set_data;
+    fib_entry_src_contribute_interpose_t fesv_contribute_interpose;
+    fib_entry_src_flag_change_t fesv_flags_change;
+    fib_entry_src_copy_t fesv_copy;
 } fib_entry_src_vft_t;
 
 #define FOR_EACH_SRC_ADDED(_entry, _src, _source, action)	\
 {								\
-    vec_foreach(_src, _entry->fe_srcs)				\
+    vec_foreach(_src, (_entry)->fe_srcs)                        \
     {								\
 	if (_src->fes_flags & FIB_ENTRY_SRC_FLAG_ADDED) {	\
-	    _source = _src->fes_src;				\
-	    do {						\
-		action;						\
-	    } while(0);						\
+	    _source = (_src)->fes_src;				\
+            action;						\
 	}							\
     }								\
 }
 
+#define FIB_ENTRY_SRC_VFT_INVOKE(esrc, func, args)  \
+{                                                   \
+    const fib_entry_src_vft_t *_vft;                \
+    _vft = fib_entry_src_get_vft(esrc);             \
+    if (_vft->func)                                 \
+        _vft->func args;                            \
+}
+
+#define FIB_ENTRY_SRC_VFT_INVOKE_AND_RETURN(esrc, func, args)  \
+{                                                   \
+    const fib_entry_src_vft_t *_vft;                \
+    _vft = fib_entry_src_get_vft(esrc);             \
+    if (_vft->func)                                 \
+        return (_vft->func args);                   \
+}
+
+#define FIB_ENTRY_SRC_VFT_EXISTS(esrc, func)        \
+{                                                   \
+    const fib_entry_src_vft_t *_vft;                \
+    _vft = fib_entry_src_get_vft(esrc);             \
+    (_vft->func);                                   \
+}
+
+extern const fib_entry_src_vft_t*fib_entry_src_get_vft(
+    const fib_entry_src_t *esrc);
+
 extern u8* fib_entry_src_format(fib_entry_t *entry,
 				fib_source_t source,
 				u8* s);
@@ -215,19 +262,13 @@ extern u8* fib_entry_src_format(fib_entry_t *entry,
 extern void fib_entry_src_register(fib_source_t source,
 				   const fib_entry_src_vft_t *vft);
 
-extern void fib_entry_src_action_init(fib_entry_t *entry,
-				      fib_source_t source);
-
-extern void fib_entry_src_action_deinit(fib_entry_t *fib_entry,
-					fib_source_t source);
-
 extern fib_entry_src_cover_res_t fib_entry_src_action_cover_change(
     fib_entry_t *entry,
-    fib_source_t source);
+    fib_entry_src_t *esrc);
 
 extern fib_entry_src_cover_res_t fib_entry_src_action_cover_update(
     fib_entry_t *fib_entry,
-    fib_source_t source);
+    fib_entry_src_t *esrc);
 
 extern void fib_entry_src_action_activate(fib_entry_t *fib_entry,
 					  fib_source_t source);
@@ -304,6 +345,7 @@ extern void fib_entry_source_change(fib_entry_t *fib_entry,
 extern void fib_entry_src_default_register(void);
 extern void fib_entry_src_rr_register(void);
 extern void fib_entry_src_interface_register(void);
+extern void fib_entry_src_interpose_register(void);
 extern void fib_entry_src_default_route_register(void);
 extern void fib_entry_src_special_register(void);
 extern void fib_entry_src_api_register(void);