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

1 files changed, 18 insertions, 64 deletions

diff --git a/src/vnet/adj/adj_midchain.c b/src/vnet/adj/adj_midchain.c
index 9f709ad13be..8e6a940befa 100644
--- a/src/vnet/adj/adj_midchain.c
+++ b/src/vnet/adj/adj_midchain.c
@@ -75,52 +75,37 @@ adj_get_midchain_node (vnet_link_t link)
 }
 
 static u8
-adj_midchain_get_feature_arc_index_for_link_type (const ip_adjacency_t *adj)
+adj_midchain_get_feature_arc_index (const ip_adjacency_t *adj)
 {
-    u8 arc = (u8) ~0;
     switch (adj->ia_link)
     {
     case VNET_LINK_IP4:
-	{
-	    arc = ip4_main.lookup_main.output_feature_arc_index;
-	    break;
-	}
+        return ip4_main.lookup_main.output_feature_arc_index;
     case VNET_LINK_IP6:
-	{
-	    arc = ip6_main.lookup_main.output_feature_arc_index;
-	    break;
-	}
+        return ip6_main.lookup_main.output_feature_arc_index;
     case VNET_LINK_MPLS:
-	{
-	    arc = mpls_main.output_feature_arc_index;
-	    break;
-	}
+        return mpls_main.output_feature_arc_index;
     case VNET_LINK_ETHERNET:
-	{
-	    arc = ethernet_main.output_feature_arc_index;
-	    break;
-	}
+        return ethernet_main.output_feature_arc_index;
     case VNET_LINK_NSH:
-        {
-          arc = nsh_main_placeholder.output_feature_arc_index;
-          break;
-        }
     case VNET_LINK_ARP:
-	ASSERT(0);
 	break;
     }
-
-    ASSERT (arc != (u8) ~0);
-
-    return (arc);
+    ASSERT (0);
+    return (0);
 }
 
 static u32
 adj_nbr_midchain_get_tx_node (ip_adjacency_t *adj)
 {
-    return ((adj->ia_flags & ADJ_FLAG_MIDCHAIN_NO_COUNT) ?
-            adj_midchain_tx_no_count_node.index :
-            adj_midchain_tx_node.index);
+    return (adj_midchain_tx.index);
+}
+
+static u32
+adj_nbr_midchain_get_next_node (ip_adjacency_t *adj)
+{
+    return (vnet_feature_get_end_node(adj_midchain_get_feature_arc_index(adj),
+                                      adj->rewrite_header.sw_if_index));
 }
 
 /**
@@ -131,17 +116,7 @@ adj_nbr_midchain_get_tx_node (ip_adjacency_t *adj)
 void
 adj_midchain_teardown (ip_adjacency_t *adj)
 {
-    vlib_main_t *vm = vlib_get_main();
-
     dpo_reset(&adj->sub_type.midchain.next_dpo);
-
-    vlib_worker_thread_barrier_sync(vm);
-    adj->ia_cfg_index = vnet_feature_modify_end_node(
-        adj_midchain_get_feature_arc_index_for_link_type (adj),
-        adj->rewrite_header.sw_if_index,
-        vlib_get_node_by_name (vlib_get_main(),
-                               (u8*) "interface-output")->index);
-    vlib_worker_thread_barrier_release(vm);
 }
 
 /**
@@ -155,9 +130,7 @@ adj_midchain_setup (adj_index_t adj_index,
                     const void *data,
                     adj_flags_t flags)
 {
-    vlib_main_t *vm = vlib_get_main();
     ip_adjacency_t *adj;
-    u32 tx_node;
 
     ASSERT(ADJ_INDEX_INVALID != adj_index);
 
@@ -181,15 +154,6 @@ adj_midchain_setup (adj_index_t adj_index,
         adj->rewrite_header.flags &= ~VNET_REWRITE_FIXUP_FLOW_HASH;
     }
 
-    tx_node = adj_nbr_midchain_get_tx_node(adj);
-
-    vlib_worker_thread_barrier_sync(vm);
-    adj->ia_cfg_index = vnet_feature_modify_end_node(
-        adj_midchain_get_feature_arc_index_for_link_type (adj),
-        adj->rewrite_header.sw_if_index,
-        tx_node);
-    vlib_worker_thread_barrier_release(vm);
-
     /*
      * stack the midchain on the drop so it's ready to forward in the adj-midchain-tx.
      * The graph arc used/created here is from the midchain-tx node to the
@@ -197,7 +161,7 @@ adj_midchain_setup (adj_index_t adj_index,
      * node are any output features, then the midchain-tx.  from there we
      * need to get to the stacked child's node.
      */
-    dpo_stack_from_node(tx_node,
+    dpo_stack_from_node(adj_nbr_midchain_get_tx_node(adj),
                         &adj->sub_type.midchain.next_dpo,
                         drop_dpo_get(vnet_link_to_dpo_proto(adj->ia_link)));
 }
@@ -238,7 +202,7 @@ adj_nbr_midchain_update_rewrite (adj_index_t adj_index,
     adj_nbr_update_rewrite_internal(adj,
 				    IP_LOOKUP_NEXT_MIDCHAIN,
 				    adj_get_midchain_node(adj->ia_link),
-				    adj_nbr_midchain_get_tx_node(adj),
+				    adj_nbr_midchain_get_next_node(adj),
 				    rewrite);
 }
 
@@ -260,11 +224,6 @@ adj_nbr_midchain_update_next_node (adj_index_t adj_index,
                                                         adj->ia_node_index,
                                                         next_node);
 
-    adj->ia_cfg_index = vnet_feature_modify_end_node(
-        adj_midchain_get_feature_arc_index_for_link_type (adj),
-        adj->rewrite_header.sw_if_index,
-        next_node);
-
     vlib_worker_thread_barrier_release(vm);
 }
 
@@ -284,12 +243,7 @@ adj_nbr_midchain_reset_next_node (adj_index_t adj_index)
     adj->rewrite_header.next_index =
         vlib_node_add_next(vlib_get_main(),
                            adj->ia_node_index,
-                           adj_nbr_midchain_get_tx_node(adj));
-
-    adj->ia_cfg_index = vnet_feature_modify_end_node(
-        adj_midchain_get_feature_arc_index_for_link_type (adj),
-        adj->rewrite_header.sw_if_index,
-        adj_nbr_midchain_get_tx_node(adj));
+                           adj_nbr_midchain_get_next_node(adj));
 
     vlib_worker_thread_barrier_release(vm);
 }