Reorganize source tree to use single autotools instance

Change-Id: I7b51f88292e057c6443b12224486f2d0c9f8ae23
Signed-off-by: Damjan Marion <damarion@cisco.com>

1 files changed, 301 insertions, 0 deletions

diff --git a/src/vnet/feature/registration.c b/src/vnet/feature/registration.c
new file mode 100644
index 00000000000..1deeeef904c
--- /dev/null
+++ b/src/vnet/feature/registration.c
@@ -0,0 +1,301 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <vnet/vnet.h>
+#include <vnet/ip/ip.h>
+#include <vnet/mpls/mpls.h>
+
+/**
+ * @file
+ * @brief Feature Subgraph Ordering.
+
+    Dynamically compute feature subgraph ordering by performing a
+    topological sort across a set of "feature A before feature B" and
+    "feature C after feature B" constraints.
+
+    Use the topological sort result to set up vnet_config_main_t's for
+    use at runtime.
+
+    Feature subgraph arcs are simple enough. They start at specific
+    fixed nodes, and end at specific fixed nodes.  In between, a
+    per-interface current feature configuration dictates which
+    additional nodes each packet visits. Each so-called feature node
+    can [of course] drop any specific packet.
+
+    See ip4_forward.c, ip6_forward.c in this directory to see the
+    current rx-unicast, rx-multicast, and tx feature subgraph arc
+    definitions.
+
+    Let's say that we wish to add a new feature to the ip4 unicast
+    feature subgraph arc, which needs to run before @c ip4-lookup.  In
+    either base code or a plugin,
+    <CODE><PRE>
+    \#include <vnet/feature/feature.h>
+    </PRE></CODE>
+
+    and add the new feature as shown:
+
+    <CODE><PRE>
+    VNET_FEATURE_INIT (ip4_lookup, static) =
+    {
+      .arch_name = "ip4-unicast",
+      .node_name = "my-ip4-unicast-feature",
+      .runs_before = VLIB_FEATURES ("ip4-lookup")
+    };
+    </PRE></CODE>
+
+    Here's the standard coding pattern to enable / disable
+    @c my-ip4-unicast-feature on an interface:
+
+    <CODE><PRE>
+
+    sw_if_index = <interface-handle>
+    vnet_feature_enable_disable ("ip4-unicast", "my-ip4-unicast-feature",
+                                 sw_if_index, 1 );
+    </PRE></CODE>
+
+    Here's how to obtain the correct next node index in packet
+    processing code, aka in the implementation of @c my-ip4-unicast-feature:
+
+    <CODE><PRE>
+    vnet_feature_next (sw_if_index0, &next0, b0);
+
+    </PRE></CODE>
+
+    Nodes are free to drop or otherwise redirect packets. Packets
+    which "pass" should be enqueued via the next0 arc computed by
+    vnet_feature_next.
+*/
+
+
+static int
+comma_split (u8 * s, u8 ** a, u8 ** b)
+{
+  *a = s;
+
+  while (*s && *s != ',')
+    s++;
+
+  if (*s == ',')
+    *s = 0;
+  else
+    return 1;
+
+  *b = (u8 *) (s + 1);
+  return 0;
+}
+
+/**
+ * @brief Initialize a feature graph arc
+ * @param vm vlib main structure pointer
+ * @param vcm vnet config main structure pointer
+ * @param feature_start_nodes names of start-nodes which use this
+ *	  feature graph arc
+ * @param num_feature_start_nodes number of start-nodes
+ * @param first_reg first element in
+ *        [an __attribute__((constructor)) function built, or
+ *        otherwise created] singly-linked list of feature registrations
+ * @param [out] in_feature_nodes returned vector of
+ *        topologically-sorted feature node names, for use in
+ *        show commands
+ * @returns 0 on success, otherwise an error message. Errors
+ *        are fatal since they invariably involve mistyped node-names, or
+ *        genuinely missing node-names
+ */
+clib_error_t *
+vnet_feature_arc_init (vlib_main_t * vm,
+		       vnet_config_main_t * vcm,
+		       char **feature_start_nodes,
+		       int num_feature_start_nodes,
+		       vnet_feature_registration_t * first_reg,
+		       char ***in_feature_nodes)
+{
+  uword *index_by_name;
+  uword *reg_by_index;
+  u8 **node_names = 0;
+  u8 *node_name;
+  char **these_constraints;
+  char *this_constraint_c;
+  u8 **constraints = 0;
+  u8 *constraint_tuple;
+  u8 *this_constraint;
+  u8 **orig, **closure;
+  uword *p;
+  int i, j, k;
+  u8 *a_name, *b_name;
+  int a_index, b_index;
+  int n_features;
+  u32 *result = 0;
+  vnet_feature_registration_t *this_reg = 0;
+  char **feature_nodes = 0;
+  hash_pair_t *hp;
+  u8 **keys_to_delete = 0;
+
+  index_by_name = hash_create_string (0, sizeof (uword));
+  reg_by_index = hash_create (0, sizeof (uword));
+
+  this_reg = first_reg;
+
+  /* pass 1, collect feature node names, construct a before b pairs */
+  while (this_reg)
+    {
+      node_name = format (0, "%s%c", this_reg->node_name, 0);
+      hash_set (reg_by_index, vec_len (node_names), (uword) this_reg);
+
+      hash_set_mem (index_by_name, node_name, vec_len (node_names));
+
+      vec_add1 (node_names, node_name);
+
+      these_constraints = this_reg->runs_before;
+      while (these_constraints && these_constraints[0])
+	{
+	  this_constraint_c = these_constraints[0];
+
+	  constraint_tuple = format (0, "%s,%s%c", node_name,
+				     this_constraint_c, 0);
+	  vec_add1 (constraints, constraint_tuple);
+	  these_constraints++;
+	}
+
+      these_constraints = this_reg->runs_after;
+      while (these_constraints && these_constraints[0])
+	{
+	  this_constraint_c = these_constraints[0];
+
+	  constraint_tuple = format (0, "%s,%s%c",
+				     this_constraint_c, node_name, 0);
+	  vec_add1 (constraints, constraint_tuple);
+	  these_constraints++;
+	}
+
+      this_reg = this_reg->next;
+    }
+
+  n_features = vec_len (node_names);
+  orig = clib_ptclosure_alloc (n_features);
+
+  for (i = 0; i < vec_len (constraints); i++)
+    {
+      this_constraint = constraints[i];
+
+      if (comma_split (this_constraint, &a_name, &b_name))
+	return clib_error_return (0, "comma_split failed!");
+
+      p = hash_get_mem (index_by_name, a_name);
+      /*
+       * Note: the next two errors mean that something is
+       * b0rked. As in: if you code "A depends on B," and you forget
+       * to define a FEATURE_INIT macro for B, you lose.
+       * Nonexistent graph nodes are tolerated.
+       */
+      if (p == 0)
+	return clib_error_return (0, "feature node '%s' not found", a_name);
+      a_index = p[0];
+
+      p = hash_get_mem (index_by_name, b_name);
+      if (p == 0)
+	return clib_error_return (0, "feature node '%s' not found", b_name);
+      b_index = p[0];
+
+      /* add a before b to the original set of constraints */
+      orig[a_index][b_index] = 1;
+      vec_free (this_constraint);
+    }
+
+  /* Compute the positive transitive closure of the original constraints */
+  closure = clib_ptclosure (orig);
+
+  /* Compute a partial order across feature nodes, if one exists. */
+again:
+  for (i = 0; i < n_features; i++)
+    {
+      for (j = 0; j < n_features; j++)
+	{
+	  if (closure[i][j])
+	    goto item_constrained;
+	}
+      /* Item i can be output */
+      vec_add1 (result, i);
+      {
+	for (k = 0; k < n_features; k++)
+	  closure[k][i] = 0;
+	/*
+	 * Add a "Magic" a before a constraint.
+	 * This means we'll never output it again
+	 */
+	closure[i][i] = 1;
+	goto again;
+      }
+    item_constrained:
+      ;
+    }
+
+  /* see if we got a partial order... */
+  if (vec_len (result) != n_features)
+    return clib_error_return (0, "%d feature_init_cast no partial order!");
+
+  /*
+   * We win.
+   * Bind the index variables, and output the feature node name vector
+   * using the partial order we just computed. Result is in stack
+   * order, because the entry with the fewest constraints (e.g. none)
+   * is output first, etc.
+   */
+
+  for (i = n_features - 1; i >= 0; i--)
+    {
+      p = hash_get (reg_by_index, result[i]);
+      ASSERT (p != 0);
+      this_reg = (vnet_feature_registration_t *) p[0];
+      if (this_reg->feature_index_ptr)
+	*this_reg->feature_index_ptr = n_features - (i + 1);
+      this_reg->feature_index = n_features - (i + 1);
+      vec_add1 (feature_nodes, this_reg->node_name);
+    }
+
+  /* Set up the config infrastructure */
+  vnet_config_init (vm, vcm,
+		    feature_start_nodes,
+		    num_feature_start_nodes,
+		    feature_nodes, vec_len (feature_nodes));
+
+  /* Save a copy for show command */
+  *in_feature_nodes = feature_nodes;
+
+  /* Finally, clean up all the shit we allocated */
+  /* *INDENT-OFF* */
+  hash_foreach_pair (hp, index_by_name,
+  ({
+    vec_add1 (keys_to_delete, (u8 *)hp->key);
+  }));
+  /* *INDENT-ON* */
+  hash_free (index_by_name);
+  for (i = 0; i < vec_len (keys_to_delete); i++)
+    vec_free (keys_to_delete[i]);
+  vec_free (keys_to_delete);
+  hash_free (reg_by_index);
+  vec_free (result);
+  clib_ptclosure_free (orig);
+  clib_ptclosure_free (closure);
+  return 0;
+}
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */