Date: Sun, 26 Feb 2023 13:16:02 GMT From: Gordon Bergling <gbe@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: b06338167d64 - main - route.8: Add information about ROUTE_MPATH and FIB_ALGO Message-ID: <202302261316.31QDG2s0077522@gitrepo.freebsd.org>
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The branch main has been updated by gbe: URL: https://cgit.FreeBSD.org/src/commit/?id=b06338167d64507e79e003500002e22fbe583832 commit b06338167d64507e79e003500002e22fbe583832 Author: Gordon Bergling <gbe@FreeBSD.org> AuthorDate: 2023-02-26 13:15:34 +0000 Commit: Gordon Bergling <gbe@FreeBSD.org> CommitDate: 2023-02-26 13:15:34 +0000 route.8: Add information about ROUTE_MPATH and FIB_ALGO Since the kernel options ROUTE_MPATH and FIB_ALGO are enabled per default for a while, it's good to have some user facing documetation about the general functionality of multipath routing and fib lookup algorithms. Reviewed by: pauamma, Jose Luis Duran <jlduran at gmail dot com> MFC after: 5 days Differential Revision: https://reviews.freebsd.org/D38783 --- sbin/route/route.8 | 57 +++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 56 insertions(+), 1 deletion(-) diff --git a/sbin/route/route.8 b/sbin/route/route.8 index 161189e7a9d8..c893ae5ab4b3 100644 --- a/sbin/route/route.8 +++ b/sbin/route/route.8 @@ -28,7 +28,7 @@ .\" @(#)route.8 8.3 (Berkeley) 3/19/94 .\" $FreeBSD$ .\" -.Dd December 15, 2021 +.Dd February 26, 2023 .Dt ROUTE 8 .Os .Sh NAME @@ -405,6 +405,60 @@ and .Dv RTM_CHANGE . As such, only the super-user may modify the routing tables. +.Pp +.Fx provides support for scalable multipath routing. +It is activated by default, but can be turned off by setting the +.Va net.route.multipath +.Xr sysctl 8 +MIB to 0. +.Pp +There are multiple route lookup algorithms available. +They can be configured by setting +.Va net.route.algo.inet.algo +for IPv4 and +.Va net.route.algo.inet6.algo +for IPv6 +.Xr sysctl 8 +MIBs. +.Pp +A list of available algorithms can be obtained by accessing the +following +.Xr sysctl 8 +MIBs +.Va net.route.algo.inet.algo_list +for IPv4 and +.Va net.route.algo.inet6.algo_list +for IPv6. +.Pp +The following algorithms are available: +.Bl -tag -width radix_lockless +.It radix +Base system radix backend. +.It bsearch +Lockless binary search in a special IP array, tailored for a small FIB +with <16 routes. +This algorithm is only available for IPv4. +.It radix_lockless +Lockless immutable radix, re-created on every rtable change, +tailored for a small FIB with <1000 routes. +.It dpdk_lpm +DPDK DIR24-8-based lookups, lockless datastructure, optimized +for a large FIB. +In order to use the dpdk_lpm algorithm one or both of the +following kernel modules must be loaded via +.Xr loader.conf 5 : +.Bl -tag -width dpdk_lpm6.ko -compact +.It dpdk_lpm4.ko +DPDK implementation for IPv4. +.It dpdk_lpm6.ko +DPDK implementation for IPv6. +.El +.El +.Pp +The algorithms are selected automatically based on the size of the routing +table of the system. +They can be changed, but not every algorithm performs best for every +FIB size. .Sh EXIT STATUS .Ex -std .Sh EXAMPLES @@ -484,6 +538,7 @@ The next-hop gateway should be reachable through a different route. .Xr netstat 1 , .Xr netintro 4 , .Xr route 4 , +.Xr loader.conf 5 , .Xr arp 8 , .Xr routed 8 .Sh HISTORY
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