fib: Don't use [midchain] adjacencies to change an interface's feature arc

Type: fix

Using the adjacency to modify the interface's feature arc doesn't work, since there are potentially more than one adj per-interface.
Instead have the interface, when it is created, register what the end node of the feature arc is. This end node is then also used as the interface's tx node (i.e. it is used as the adjacency's next-node).

rename adj-midhcain-tx as 'tunnel-output', that's a bit more intuitive.

There's also a fix in config string handling to:
 1- prevent false sharing of strings when the end node of the arc is different.
 2- call registered listeners when the end node is changed

For IPSec the consequences are that one cannot provide per-adjacency behaviour using different end-nodes - this was previously done for the no-SA and an SA with no protection. These cases are no handled in the esp-encrypt node.

Signed-off-by: Neale Ranns <neale@graphiant.com>
Change-Id: If3a83d03a3000f28820d9a9cb4101d244803d084

2 files changed, 63 insertions, 1 deletions

diff --git a/src/vnet/feature/feature.c b/src/vnet/feature/feature.c
index c93f586c349..1750612783b 100644
--- a/src/vnet/feature/feature.c
+++ b/src/vnet/feature/feature.c
@@ -293,9 +293,10 @@ vnet_feature_enable_disable_with_index (u8 arc_index, u32 feature_index,
   fm->sw_if_index_has_features[arc_index] =
     clib_bitmap_set (fm->sw_if_index_has_features[arc_index], sw_if_index,
 		     (feature_count > 0));
+  fm->feature_count_by_sw_if_index[arc_index][sw_if_index] = feature_count;
+
   vnet_feature_reg_invoke (sw_if_index, arc_index, (feature_count > 0));
 
-  fm->feature_count_by_sw_if_index[arc_index][sw_if_index] = feature_count;
   return 0;
 }
 
@@ -375,6 +376,52 @@ vnet_feature_is_enabled (const char *arc_name, const char *feature_node_name,
   return 0;
 }
 
+u32
+vnet_feature_get_end_node (u8 arc_index, u32 sw_if_index)
+{
+  vnet_feature_main_t *fm = &feature_main;
+  vnet_feature_config_main_t *cm;
+  u32 ci;
+
+  if (arc_index == (u8) ~0)
+    return VNET_API_ERROR_INVALID_VALUE;
+
+  cm = &fm->feature_config_mains[arc_index];
+  vec_validate_init_empty (cm->config_index_by_sw_if_index, sw_if_index, ~0);
+  ci = cm->config_index_by_sw_if_index[sw_if_index];
+
+  return (vnet_config_get_end_node (vlib_get_main (), &cm->config_main, ci));
+}
+
+u32
+vnet_feature_reset_end_node (u8 arc_index, u32 sw_if_index)
+{
+  vnet_feature_main_t *fm = &feature_main;
+  vnet_feature_config_main_t *cm;
+  u32 ci;
+
+  cm = &fm->feature_config_mains[arc_index];
+  vec_validate_init_empty (cm->config_index_by_sw_if_index, sw_if_index, ~0);
+  ci = cm->config_index_by_sw_if_index[sw_if_index];
+
+  ci = vnet_config_reset_end_node (vlib_get_main (), &cm->config_main, ci);
+
+  if (ci != ~0)
+    cm->config_index_by_sw_if_index[sw_if_index] = ci;
+
+  i16 feature_count;
+
+  if (NULL == fm->feature_count_by_sw_if_index ||
+      vec_len (fm->feature_count_by_sw_if_index) <= arc_index ||
+      vec_len (fm->feature_count_by_sw_if_index[arc_index]) <= sw_if_index)
+    feature_count = 0;
+  else
+    feature_count = fm->feature_count_by_sw_if_index[arc_index][sw_if_index];
+
+  vnet_feature_reg_invoke (sw_if_index, arc_index, (feature_count > 0));
+
+  return ci;
+}
 
 u32
 vnet_feature_modify_end_node (u8 arc_index,
@@ -400,6 +447,17 @@ vnet_feature_modify_end_node (u8 arc_index,
   if (ci != ~0)
     cm->config_index_by_sw_if_index[sw_if_index] = ci;
 
+  i16 feature_count;
+
+  if (NULL == fm->feature_count_by_sw_if_index ||
+      vec_len (fm->feature_count_by_sw_if_index) <= arc_index ||
+      vec_len (fm->feature_count_by_sw_if_index[arc_index]) <= sw_if_index)
+    feature_count = 0;
+  else
+    feature_count = fm->feature_count_by_sw_if_index[arc_index][sw_if_index];
+
+  vnet_feature_reg_invoke (sw_if_index, arc_index, (feature_count > 0));
+
   return ci;
 }
 
diff --git a/src/vnet/feature/feature.h b/src/vnet/feature/feature.h
index 9aa32182ef6..a8235d3d9ee 100644
--- a/src/vnet/feature/feature.h
+++ b/src/vnet/feature/feature.h
@@ -222,6 +222,10 @@ vnet_feature_enable_disable (const char *arc_name, const char *node_name,
 u32
 vnet_feature_modify_end_node (u8 arc_index, u32 sw_if_index, u32 node_index);
 
+u32 vnet_feature_get_end_node (u8 arc_index, u32 sw_if_index);
+
+u32 vnet_feature_reset_end_node (u8 arc_index, u32 sw_if_index);
+
 static_always_inline u32
 vnet_get_feature_count (u8 arc, u32 sw_if_index)
 {