lib: Add Aggregate Table and Aggregate_node

Add a abstraction for `struct route_node` and `struct route_table`
such that we can have an aggregate route_node and table.  This
is because only bgp/rfapi and ripng use the aggregate data pointer
in `struct route_node`.  For full route tables other routing
protocols and tables are paying a 8 byte overhead per node.
A full bgp table ends up being ~1.2 million routes in bgp
and zebra.  This is not an insiginificant amount of data.

So create the data structures for this replacement, but
do not replace the aggregate pointer yet.  This is because
later commits will convert rfapi and ripng over to this
new data, and finally we'll move the aggregate pointer.

Signed-off-by: Donald Sharp <sharpd@cumulusnetworks.com>

lib/agg_table.c

@@ -0,0 +1,59 @@
+/*
+ * Aggregate Route
+ * Copyright (C) 2018 Cumulus Networks, Inc.
+ *               Donald Sharp
+ *
+ * FRR is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * FRR is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; see the file COPYING; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#include "zebra.h"
+
+#include "agg_table.h"
+
+
+static struct route_node *agg_node_create(route_table_delegate_t *delegate,
+					  struct route_table *table)
+{
+	struct agg_node *node;
+
+	node = XCALLOC(MTYPE_TMP, sizeof(struct agg_node));
+
+	return agg_node_to_rnode(node);
+}
+
+static void agg_node_destroy(route_table_delegate_t *delegate,
+			     struct route_table *table, struct route_node *node)
+
+{
+	struct agg_node *anode = agg_node_from_rnode(node);
+
+	XFREE(MTYPE_TMP, anode);
+}
+
+route_table_delegate_t agg_table_delegate = {
+	.create_node = agg_node_create,
+	.destroy_node = agg_node_destroy,
+};
+
+extern struct agg_table *agg_table_init(void)
+{
+	struct agg_table *at;
+
+	at = XCALLOC(MTYPE_TMP, sizeof(struct agg_table));
+
+	at->route_table = route_table_init_with_delegate(&agg_table_delegate);
+	at->route_table->info = at;
+
+	return at;
+}

lib/agg_table.h

@@ -0,0 +1,151 @@
+/*
+ * agg_table - Aggregate Table Header
+ * Copyright (C) 2018 Cumulus Networks, Inc.
+ *               Donald Sharp
+ *
+ * FRR is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2, or (at your option) any
+ * later version.
+ *
+ * FRR is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; see the file COPYING; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+#ifndef __AGG_TABLE_H__
+#define __AGG_TABLE_H__
+
+#include "prefix.h"
+#include "table.h"
+
+struct agg_table {
+	struct route_table *route_table;
+
+	void *info;
+};
+
+struct agg_node {
+	/*
+	 * Caution these must be the very first fields
+	 * @see agg_node_to_rnode
+	 * @see agg_node_from_rnode
+	 */
+	ROUTE_NODE_FIELDS
+
+};
+
+static inline struct route_node *agg_node_to_rnode(struct agg_node *node)
+{
+	return (struct route_node *)node;
+}
+
+static inline struct agg_node *agg_node_from_rnode(struct route_node *node)
+{
+	return (struct agg_node *)node;
+}
+
+static inline struct agg_node *agg_lock_node(struct agg_node *node)
+{
+	return (struct agg_node *)route_lock_node(agg_node_to_rnode(node));
+}
+
+static inline void agg_unlock_node(struct agg_node *node)
+{
+	return route_unlock_node(agg_node_to_rnode(node));
+}
+
+static inline void agg_set_table_info(struct agg_table *atable, void *data)
+{
+       atable->info = data;
+}
+
+static inline void *agg_get_table_info(struct agg_table *atable)
+{
+       return atable->info;
+}
+
+static inline struct agg_node *agg_route_top(struct agg_table *table)
+{
+	return agg_node_from_rnode(route_top(table->route_table));
+}
+
+static inline struct agg_node *agg_route_next(struct agg_node *node)
+{
+	return agg_node_from_rnode(route_next(agg_node_to_rnode(node)));
+}
+
+static inline struct agg_node *agg_node_get(struct agg_table *table,
+					    struct prefix *p)
+{
+	return agg_node_from_rnode(route_node_get(table->route_table, p));
+}
+
+static inline struct agg_node *
+agg_node_lookup(const struct agg_table *const table, struct prefix *p)
+{
+	return agg_node_from_rnode(route_node_lookup(table->route_table, p));
+}
+
+static inline struct agg_node *agg_route_next_until(struct agg_node *node,
+						    struct agg_node *limit)
+{
+	struct route_node *rnode;
+
+	rnode = route_next_until(agg_node_to_rnode(node),
+				agg_node_to_rnode(limit));
+
+	return agg_node_from_rnode(rnode);
+}
+
+static inline struct agg_node *agg_node_match(struct agg_table *table,
+					      struct prefix *p)
+{
+	return agg_node_from_rnode(route_node_match(table->route_table, p));
+}
+
+static inline struct agg_node *agg_node_parent(struct agg_node *node)
+{
+	struct route_node *rn = agg_node_to_rnode(node);
+
+	return agg_node_from_rnode(rn->parent);
+}
+
+static inline struct agg_node *agg_node_left(struct agg_node *node)
+{
+	struct route_node *rn = agg_node_to_rnode(node);
+
+	return agg_node_from_rnode(rn->l_left);
+}
+
+static inline struct agg_node *agg_node_right(struct agg_node *node)
+{
+	struct route_node *rn = agg_node_to_rnode(node);
+
+	return agg_node_from_rnode(rn->l_right);
+}
+
+extern struct agg_table *agg_table_init(void);
+
+static inline void agg_table_finish(struct agg_table *atable)
+{
+	route_table_finish(atable->route_table);
+	atable->route_table = NULL;
+
+	XFREE(MTYPE_TMP, atable);
+}
+
+static inline struct agg_node *agg_route_table_top(struct agg_node *node)
+{
+	return (struct agg_node *)route_top(node->table);
+}
+
+static inline struct agg_table *agg_get_table(struct agg_node *node)
+{
+	return (struct agg_table *)node->table->info;
+}
+#endif

lib/subdir.am

@@ -6,6 +6,7 @@ lib_libfrr_la_LDFLAGS = -version-info 0:0:0
 lib_libfrr_la_LIBADD = @LIBCAP@
 
 lib_libfrr_la_SOURCES = \
+	lib/agg_table.c \
 	lib/bfd.c \
 	lib/buffer.c \
 	lib/checksum.c \
@@ -89,6 +90,7 @@ lib/nexthop_group_clippy.c: $(CLIPPY_DEPS)
 lib/nexthop_group.lo: lib/nexthop_group_clippy.c
 
 pkginclude_HEADERS += \
+	lib/agg_table.h \
 	lib/bfd.h \
 	lib/bitfield.h \
 	lib/buffer.h \