fedeb08b6a
This change is based on the nexthop objects landed in D24232.
The change introduces the concept of nexthop groups.
Each group contains the collection of nexthops with their
relative weights and a dataplane-optimized structure to enable
efficient nexthop selection.
Simular to the nexthops, nexthop groups are immutable. Dataplane part
gets compiled during group creation and is basically an array of
nexthop pointers, compiled w.r.t their weights.
With this change, `rt_nhop` field of `struct rtentry` contains either
nexthop or nexthop group. They are distinguished by the presense of
NHF_MULTIPATH flag.
All dataplane lookup functions returns pointer to the nexthop object,
leaving nexhop groups details inside routing subsystem.
User-visible changes:
The change is intended to be backward-compatible: all non-mpath operations
should work as before with ROUTE_MPATH and net.route.multipath=1.
All routes now comes with weight, default weight is 1, maximum is 2^24-1.
Current maximum multipath group width is statically set to 64.
This will become sysctl-tunable in the followup changes.
Using functionality:
* Recompile kernel with ROUTE_MPATH
* set net.route.multipath to 1
route add -6 2001:db8::/32 2001:db8::2 -weight 10
route add -6 2001:db8::/32 2001:db8::3 -weight 20
netstat -6On
Nexthop groups data
Internet6:
GrpIdx NhIdx Weight Slots Gateway Netif Refcnt
1 ------- ------- ------- --------------------------------------- --------- 1
13 10 1 2001:db8::2 vlan2
14 20 2 2001:db8::3 vlan2
Next steps:
* Land outbound hashing for locally-originated routes ( D26523 ).
* Fix net/bird multipath (net/frr seems to work fine)
* Add ROUTE_MPATH to GENERIC
* Set net.route.multipath=1 by default
Tested by: olivier
Reviewed by: glebius
Relnotes: yes
Differential Revision: https://reviews.freebsd.org/D26449
73 lines
2.9 KiB
C
73 lines
2.9 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 2020 Alexander V. Chernikov
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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/*
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* This header file contains private definitions for the nexthop groups.
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*
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* Header is not intended to be included by the code external to the
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* routing subsystem.
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*/
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#ifndef _NET_ROUTE_NHGRP_VAR_H_
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#define _NET_ROUTE_NHGRP_VAR_H_
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/* nhgrp hash definition */
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/* produce hash value for an object */
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#define mpath_hash_obj(_obj) (hash_nhgrp(_obj))
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/* compare two objects */
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#define mpath_cmp(_one, _two) (cmp_nhgrp(_one, _two))
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/* next object accessor */
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#define mpath_next(_obj) (_obj)->nhg_priv_next
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struct nhgrp_priv {
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uint32_t nhg_idx;
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uint8_t nhg_nh_count; /* number of items in nh_weights */
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uint8_t nhg_spare[3];
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u_int nhg_refcount; /* use refcount */
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u_int nhg_linked; /* refcount(9), == 2 if linked to the list */
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struct nh_control *nh_control; /* parent control structure */
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struct nhgrp_priv *nhg_priv_next;
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struct nhgrp_object *nhg;
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struct epoch_context nhg_epoch_ctx; /* epoch data for nhop */
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struct weightened_nhop nhg_nh_weights[0];
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};
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#define _NHGRP_PRIV(_src) (&(_src)->nhops[(_src)->nhg_size])
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#define NHGRP_PRIV(_src) ((struct nhgrp_priv *)_NHGRP_PRIV(_src))
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#define NHGRP_PRIV_CONST(_src) ((const struct nhgrp_priv *)_NHGRP_PRIV(_src))
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/* nhgrp.c */
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bool nhgrp_ctl_alloc_default(struct nh_control *ctl, int malloc_flags);
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struct nhgrp_priv *find_nhgrp(struct nh_control *ctl, const struct nhgrp_priv *key);
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int link_nhgrp(struct nh_control *ctl, struct nhgrp_priv *grp_priv);
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struct nhgrp_priv *unlink_nhgrp(struct nh_control *ctl, struct nhgrp_priv *key);
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#endif
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