forked from Mirror/frr
lib: add second-level route_table for srcdest
IPv6 srcdest routes need to be keyed by both destination and source prefix. Since the lookup order is destination first, the simplest thing to do here is to add a second route_table to destination entries, which then contain source entries. Sadly, the result is somewhat confusing since a route_node might now be either a source node or a destination node. There are helper functions to get source and destination prefix from a given route node (which can be either a destination or a source route). The following bits have been added by Christian Franke <chris@opensourcerouting.org>: - make srcdest routing table reusable by moving it into lib - make the srcdest routing table structure more opaque - implement a srcdest routing table iterator - fix a refcounting issue in src_node_lookup - match route_node_lookup behavior with srcdest_rnode_lookup - add accessor for the route_node table and table_info - add string formatter srcdest_rnode2str Signed-off-by: David Lamparter <equinox@opensourcerouting.org> Signed-off-by: Christian Franke <chris@opensourcerouting.org> [v3: adapted for cmaster-next as of 2016-12-05]
This commit is contained in:
David Lamparter
Christian Franke
parent
61cdc88971
commit
0964ad9cec
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@ -27,6 +27,7 @@ libzebra_la_SOURCES = \
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qobj.c wheel.c \
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event_counter.c \
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grammar_sandbox.c \
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srcdest_table.c \
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strlcpy.c \
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strlcat.c
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@ -48,7 +49,8 @@ pkginclude_HEADERS = \
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fifo.h memory_vty.h mpls.h imsg.h openbsd-queue.h openbsd-tree.h \
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skiplist.h qobj.h wheel.h \
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event_counter.h \
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monotime.h
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monotime.h \
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srcdest_table.h
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noinst_HEADERS = \
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plist_int.h
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312
lib/srcdest_table.c
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312
lib/srcdest_table.c
Normal file
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@ -0,0 +1,312 @@
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/*
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* SRC-DEST Routing Table
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*
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* Copyright (C) 2017 by David Lamparter & Christian Franke,
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* Open Source Routing / NetDEF Inc.
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*
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* This file is part of FreeRangeRouting (FRR)
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*
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* FRR is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2, or (at your option) any
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* later version.
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*
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* FRR is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with FRR; see the file COPYING. If not, write to the Free
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* Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
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* 02111-1307, USA.
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*/
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#include <zebra.h>
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#include "srcdest_table.h"
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#include "memory.h"
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#include "prefix.h"
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#include "table.h"
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DEFINE_MTYPE_STATIC(LIB, ROUTE_SRC_NODE, "Route source node")
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/* ----- functions to manage rnodes _with_ srcdest table ----- */
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struct srcdest_rnode
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{
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/* must be first in structure for casting to/from route_node */
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ROUTE_NODE_FIELDS;
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struct route_table *src_table;
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};
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static struct srcdest_rnode *
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srcdest_rnode_from_rnode (struct route_node *rn)
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{
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assert (rnode_is_dstnode (rn));
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return (struct srcdest_rnode *) rn;
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}
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static struct route_node *
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srcdest_rnode_to_rnode (struct srcdest_rnode *srn)
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{
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return (struct route_node *) srn;
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}
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static struct route_node *
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srcdest_rnode_create (route_table_delegate_t *delegate,
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struct route_table *table)
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{
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struct srcdest_rnode *srn;
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srn = XCALLOC (MTYPE_ROUTE_NODE, sizeof (struct srcdest_rnode));
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return srcdest_rnode_to_rnode(srn);
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}
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static void
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srcdest_rnode_destroy (route_table_delegate_t *delegate,
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struct route_table *table, struct route_node *rn)
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{
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struct srcdest_rnode *srn = srcdest_rnode_from_rnode(rn);
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struct route_table *src_table;
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/* Clear route node's src_table here already, otherwise the
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* deletion of the last node in the src_table will trigger
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* another call to route_table_finish for the src_table.
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*
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* (Compare with srcdest_srcnode_destroy)
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*/
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src_table = srn->src_table;
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srn->src_table = NULL;
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route_table_finish(src_table);
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XFREE (MTYPE_ROUTE_NODE, rn);
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}
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route_table_delegate_t _srcdest_dstnode_delegate = {
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.create_node = srcdest_rnode_create,
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.destroy_node = srcdest_rnode_destroy
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};
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/* ----- functions to manage rnodes _in_ srcdest table ----- */
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/* node creation / deletion for srcdest source prefix nodes.
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* the route_node isn't actually different from the normal route_node,
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* but the cleanup is special to free the table (and possibly the
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* destination prefix's route_node) */
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static struct route_node *
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srcdest_srcnode_create (route_table_delegate_t *delegate,
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struct route_table *table)
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{
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return XCALLOC (MTYPE_ROUTE_SRC_NODE, sizeof (struct route_node));
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}
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static void
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srcdest_srcnode_destroy (route_table_delegate_t *delegate,
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struct route_table *table, struct route_node *rn)
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{
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struct srcdest_rnode *srn;
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XFREE (MTYPE_ROUTE_SRC_NODE, rn);
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srn = table->info;
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if (srn->src_table && route_table_count (srn->src_table) == 0)
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{
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/* deleting the route_table from inside destroy_node is ONLY
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* permitted IF table->count is 0! see lib/table.c route_node_delete()
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* for details */
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route_table_finish (srn->src_table);
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srn->src_table = NULL;
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/* drop the ref we're holding in srcdest_node_get(). there might be
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* non-srcdest routes, so the route_node may still exist. hence, it's
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* important to clear src_table above. */
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route_unlock_node (srcdest_rnode_to_rnode (srn));
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}
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}
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route_table_delegate_t _srcdest_srcnode_delegate = {
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.create_node = srcdest_srcnode_create,
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.destroy_node = srcdest_srcnode_destroy
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};
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/* NB: read comments in code for refcounting before using! */
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static struct route_node *
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srcdest_srcnode_get (struct route_node *rn, struct prefix_ipv6 *src_p)
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{
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struct srcdest_rnode *srn;
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if (!src_p || src_p->prefixlen == 0)
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return rn;
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srn = srcdest_rnode_from_rnode (rn);
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if (!srn->src_table)
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{
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/* this won't use srcdest_rnode, we're already on the source here */
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srn->src_table = route_table_init_with_delegate (&_srcdest_srcnode_delegate);
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srn->src_table->info = srn;
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/* there is no route_unlock_node on the original rn here.
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* The reference is kept for the src_table. */
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}
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else
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{
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/* only keep 1 reference for the src_table, makes the refcounting
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* more similar to the non-srcdest case. Either way after return from
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* function, the only reference held is the one on the return value.
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*
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* We can safely drop our reference here because src_table is holding
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* another reference, so this won't free rn */
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route_unlock_node (rn);
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}
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return route_node_get (srn->src_table, (struct prefix *)src_p);
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}
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static struct route_node *
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srcdest_srcnode_lookup (struct route_node *rn, struct prefix_ipv6 *src_p)
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{
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struct srcdest_rnode *srn;
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if (!rn || !src_p || src_p->prefixlen == 0)
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return rn;
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/* We got this rn from a lookup, so its refcnt was incremented. As we won't
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* return return rn from any point beyond here, we should decrement its refcnt.
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*/
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route_unlock_node (rn);
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srn = srcdest_rnode_from_rnode (rn);
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if (!srn->src_table)
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return NULL;
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return route_node_lookup (srn->src_table, (struct prefix *)src_p);
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}
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/* ----- exported functions ----- */
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struct route_table *
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srcdest_table_init(void)
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{
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return route_table_init_with_delegate(&_srcdest_dstnode_delegate);
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}
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struct route_node *
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srcdest_route_next(struct route_node *rn)
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{
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struct route_node *next, *parent;
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/* For a non src-dest node, just return route_next */
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if (!(rnode_is_dstnode(rn) || rnode_is_srcnode(rn)))
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return route_next(rn);
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if (rnode_is_dstnode(rn))
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{
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/* This means the route_node is part of the top hierarchy
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* and refers to a destination prefix. */
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struct srcdest_rnode *srn = srcdest_rnode_from_rnode(rn);
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if (srn->src_table)
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next = route_top(srn->src_table);
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else
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next = NULL;
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if (next)
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{
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/* There is a source prefix. Return the node for it */
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route_unlock_node(rn);
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return next;
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}
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else
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{
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/* There is no source prefix, just continue as usual */
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return route_next(rn);
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}
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}
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/* This part handles the case of iterating source nodes. */
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parent = route_lock_node(rn->table->info);
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next = route_next(rn);
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if (next)
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{
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/* There is another source node, continue in the source table */
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route_unlock_node(parent);
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return next;
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}
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else
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{
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/* The source table is complete, continue in the parent table */
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return route_next(parent);
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}
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}
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struct route_node *
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srcdest_rnode_get (struct route_table *table, union prefix46ptr dst_pu,
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struct prefix_ipv6 *src_p)
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{
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struct prefix_ipv6 *dst_p = dst_pu.p6;
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struct route_node *rn;
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rn = route_node_get (table, (struct prefix *) dst_p);
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return srcdest_srcnode_get (rn, src_p);
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}
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struct route_node *
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srcdest_rnode_lookup (struct route_table *table, union prefix46ptr dst_pu,
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struct prefix_ipv6 *src_p)
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{
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struct prefix_ipv6 *dst_p = dst_pu.p6;
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struct route_node *rn;
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struct route_node *srn;
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rn = route_node_lookup_maynull (table, (struct prefix *) dst_p);
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srn = srcdest_srcnode_lookup (rn, src_p);
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if (rn != NULL && rn == srn && !rn->info)
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{
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/* Match the behavior of route_node_lookup and don't return an
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* empty route-node for a dest-route */
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route_unlock_node(rn);
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return NULL;
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}
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return srn;
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}
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void
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srcdest_rnode_prefixes (struct route_node *rn, struct prefix **p,
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struct prefix **src_p)
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{
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if (rnode_is_srcnode (rn))
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{
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struct route_node *dst_rn = rn->table->info;
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if (p)
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*p = &dst_rn->p;
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if (src_p)
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*src_p = &rn->p;
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}
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else
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{
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if (p)
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*p = &rn->p;
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if (src_p)
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*src_p = NULL;
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}
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}
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const char *
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srcdest_rnode2str (struct route_node *rn, char *str, int size)
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{
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struct prefix *dst_p, *src_p;
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char dst_buf[PREFIX_STRLEN], src_buf[PREFIX_STRLEN];
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srcdest_rnode_prefixes(rn, &dst_p, &src_p);
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snprintf(str, size, "%s%s%s",
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prefix2str(dst_p, dst_buf, sizeof(dst_buf)),
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(src_p && src_p->prefixlen) ? " from " : "",
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(src_p && src_p->prefixlen) ? prefix2str(src_p, src_buf,
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sizeof(src_buf))
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: "");
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return str;
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}
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101
lib/srcdest_table.h
Normal file
101
lib/srcdest_table.h
Normal file
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@ -0,0 +1,101 @@
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/*
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* SRC-DEST Routing Table
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*
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* Copyright (C) 2017 by David Lamparter & Christian Franke,
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* Open Source Routing / NetDEF Inc.
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*
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* This file is part of FreeRangeRouting (FRR)
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*
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* FRR is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2, or (at your option) any
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* later version.
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*
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* FRR is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with FRR; see the file COPYING. If not, write to the Free
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* Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA
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* 02111-1307, USA.
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*/
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#ifndef _ZEBRA_SRC_DEST_TABLE_H
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#define _ZEBRA_SRC_DEST_TABLE_H
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/* old/IPv4/non-srcdest:
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* table -> route_node .info -> [obj]
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*
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* new/IPv6/srcdest:
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* table -...-> srcdest_rnode [prefix = dest] .info -> [obj]
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* .src_table ->
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* srcdest table -...-> route_node [prefix = src] .info -> [obj]
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*
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* non-srcdest routes (src = ::/0) are treated just like before, their
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* information being directly there in the info pointer.
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*
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* srcdest routes are found by looking up destination first, then looking
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* up the source in the "src_table". src_table contains normal route_nodes,
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* whose prefix is the _source_ prefix.
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*
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* NB: info can be NULL on the destination rnode, if there are only srcdest
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* routes for a particular destination prefix.
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*/
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#include "prefix.h"
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#include "table.h"
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#define SRCDEST2STR_BUFFER (2*PREFIX2STR_BUFFER + sizeof(" from "))
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/* extended route node for IPv6 srcdest routing */
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struct srcdest_rnode;
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extern route_table_delegate_t _srcdest_dstnode_delegate;
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extern route_table_delegate_t _srcdest_srcnode_delegate;
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extern struct route_table *srcdest_table_init(void);
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extern struct route_node *srcdest_rnode_get(struct route_table *table,
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union prefix46ptr dst_pu,
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struct prefix_ipv6 *src_p);
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extern struct route_node *srcdest_rnode_lookup(struct route_table *table,
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union prefix46ptr dst_pu,
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struct prefix_ipv6 *src_p);
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extern void srcdest_rnode_prefixes (struct route_node *rn, struct prefix **p,
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struct prefix **src_p);
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extern const char *srcdest_rnode2str(struct route_node *rn, char *str, int size);
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extern struct route_node *srcdest_route_next(struct route_node *rn);
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static inline int
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rnode_is_dstnode (struct route_node *rn)
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{
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return rn->table->delegate == &_srcdest_dstnode_delegate;
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}
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static inline int
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rnode_is_srcnode (struct route_node *rn)
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{
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return rn->table->delegate == &_srcdest_srcnode_delegate;
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}
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static inline struct route_table *
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srcdest_rnode_table (struct route_node *rn)
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{
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if (rnode_is_srcnode (rn))
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{
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struct route_node *dst_rn = rn->table->info;
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return dst_rn->table;
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}
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else
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{
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return rn->table;
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}
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}
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static inline void *
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srcdest_rnode_table_info (struct route_node *rn)
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{
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return srcdest_rnode_table(rn)->info;
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}
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#endif /* _ZEBRA_SRC_DEST_TABLE_H */
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10
lib/table.c
10
lib/table.c
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@ -28,7 +28,7 @@
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#include "sockunion.h"
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DEFINE_MTYPE( LIB, ROUTE_TABLE, "Route table")
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DEFINE_MTYPE_STATIC(LIB, ROUTE_NODE, "Route node")
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DEFINE_MTYPE( LIB, ROUTE_NODE, "Route node")
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static void route_node_delete (struct route_node *);
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static void route_table_free (struct route_table *);
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@ -400,6 +400,14 @@ route_node_delete (struct route_node *node)
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node->table->count--;
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/* WARNING: FRAGILE CODE!
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* route_node_free may have the side effect of free'ing the entire table.
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* this is permitted only if table->count got decremented to zero above,
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||||
* because in that case parent will also be NULL, so that we won't try to
|
||||
* delete a now-stale parent below.
|
||||
*
|
||||
* cf. srcdest_srcnode_destroy() in zebra/zebra_rib.c */
|
||||
|
||||
route_node_free (node->table, node);
|
||||
|
||||
/* If parent node is stub then delete it also. */
|
||||
|
|
|
|||
|
|
@ -25,6 +25,7 @@
|
|||
|
||||
#include "memory.h"
|
||||
DECLARE_MTYPE(ROUTE_TABLE)
|
||||
DECLARE_MTYPE(ROUTE_NODE)
|
||||
|
||||
/*
|
||||
* Forward declarations.
|
||||
|
|
|
|||
Loading…
Reference in a new issue