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, 40 insertions, 0 deletions

diff --git a/src/vnet/adj/adj_nbr.c b/src/vnet/adj/adj_nbr.c
index 8524c6c83ae..293badefd7d 100644
--- a/src/vnet/adj/adj_nbr.c
+++ b/src/vnet/adj/adj_nbr.c
@@ -105,6 +105,46 @@ adj_nbr_remove (adj_index_t ai,
     }
 }
 
+typedef struct adj_nbr_get_n_adjs_walk_ctx_t_
+{
+    vnet_link_t linkt;
+    u32 count;
+} adj_nbr_get_n_adjs_walk_ctx_t;
+
+static adj_walk_rc_t
+adj_nbr_get_n_adjs_walk (adj_index_t ai,
+                         void *data)
+{
+    adj_nbr_get_n_adjs_walk_ctx_t *ctx = data;
+    const ip_adjacency_t *adj;
+
+    adj = adj_get(ai);
+
+    if (ctx->linkt == adj->ia_link)
+        ctx->count++;
+
+    return (ADJ_WALK_RC_CONTINUE);
+}
+
+u32
+adj_nbr_get_n_adjs (vnet_link_t link_type, u32 sw_if_index)
+{
+    adj_nbr_get_n_adjs_walk_ctx_t ctx = {
+        .linkt = link_type,
+    };
+    fib_protocol_t fproto;
+
+    FOR_EACH_FIB_IP_PROTOCOL(fproto)
+    {
+        adj_nbr_walk (sw_if_index,
+                      fproto,
+                      adj_nbr_get_n_adjs_walk,
+                      &ctx);
+    }
+
+    return (ctx.count);
+}
+
 adj_index_t
 adj_nbr_find (fib_protocol_t nh_proto,
 	      vnet_link_t link_type,