Dynamically compute ip feature subgraph order

This change-set enables plugins to add themselves to the ip4/ip6
feature subgraphs without having to modify core vpp engine code
at all. Add VNET_IP4/IP6_UNICAST/MULTICAST_FEATURE_INIT macros
which express the required ordering constraints, and off you go.

Along the way, added an implementation of Warshall's algorithm to
vppinfra; to compute the positive transitive closure of a relation. In
this case, the relation is "feature A runs before feature B."

With that in hand, ip_feature_init_cast(...) computes a partial order
across the set of configured feature subgraph nodes.

In unit-testing, we discovered VPP-145 - ip4/6 inacl wiped out
vnet_buffer(b)->ip>current_config_index, which exists in main. So, we
fixed that by moving b->trace_index, adding b->current_config_index,
and removing the ip opaque union current_config_index.

Change-Id: Iff132116f66413dc6b31ac3377198c7a32d51f48
Signed-off-by: Dave Barach <dave@barachs.net>

1 files changed, 3 insertions, 3 deletions

diff --git a/vnet/vnet/l2tp/l2tp.c b/vnet/vnet/l2tp/l2tp.c
index 7dfbe156c46..db4b4f5a29b 100644
--- a/vnet/vnet/l2tp/l2tp.c
+++ b/vnet/vnet/l2tp/l2tp.c
@@ -577,12 +577,12 @@ int l2tpv3_interface_enable_disable (vnet_main_t * vnm,
   ip_config_main_t * rx_cm = &lm->rx_config_mains[VNET_UNICAST];
   u32 ci;
   ip6_l2tpv3_config_t config;
-  ip6_rx_feature_type_t type;
+  u32 feature_index;
 
   if (pool_is_free_index (vnm->interface_main.sw_interfaces, sw_if_index))
     return VNET_API_ERROR_INVALID_SW_IF_INDEX;
 
-  type = IP6_RX_FEATURE_L2TPV3;
+  feature_index = im->ip6_unicast_rx_feature_ipsec;
 
   ci = rx_cm->config_index_by_sw_if_index[sw_if_index];
   ci = (enable_disable
@@ -590,7 +590,7 @@ int l2tpv3_interface_enable_disable (vnet_main_t * vnm,
         : vnet_config_del_feature)
     (vlib_get_main(), &rx_cm->config_main,
      ci,
-     type,
+     feature_index,
      &config,
      sizeof (config));
   rx_cm->config_index_by_sw_if_index[sw_if_index] = ci;