lib/nexthop_group.h

   1 /*
   2  * Nexthop Group structure definition.
   3  * Copyright (C) 2018 Cumulus Networks, Inc.
   4  *                    Donald Sharp
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the Free
   8  * Software Foundation; either version 2 of the License, or (at your option)
   9  * any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  14  * more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program; see the file COPYING; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #ifndef __NEXTHOP_GROUP__
  22 #define __NEXTHOP_GROUP__
  23
  24 /*
  25  * What is a nexthop group?
  26  *
  27  * A nexthop group is a collection of nexthops that make up
  28  * the ECMP path for the route.
  29  *
  30  * This module provides a proper abstraction to this idea.
  31  */
  32 struct nexthop_group {
  33         struct nexthop *nexthop;
  34 };
  35
  36 void nexthop_group_init(void);
  37
  38 void nexthop_add(struct nexthop **target, struct nexthop *nexthop);
  39 void copy_nexthops(struct nexthop **tnh, struct nexthop *nh,
  40                    struct nexthop *rparent);
  41
  42 /* The following for loop allows to iterate over the nexthop
  43  * structure of routes.
  44  *
  45  * head:      The pointer to the first nexthop in the chain.
  46  *
  47  * nexthop:   The pointer to the current nexthop, either in the
  48  *            top-level chain or in a resolved chain.
  49  */
  50 #define ALL_NEXTHOPS(head, nhop)                                        \
  51         (nhop) = (head.nexthop);                                        \
  52         (nhop);                                                         \
  53         (nhop) = nexthop_next(nhop)
  54 #endif