From: Vincent Bernat <vincent@bernat.ch>
To: "David S. Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Jonathan Corbet <corbet@lwn.net>,
netdev@vger.kernel.org,
Andy Gospodarek <gospo@cumulusnetworks.com>,
David Ahern <dsahern@gmail.com>
Cc: Vincent Bernat <vincent@bernat.ch>
Subject: [PATCH net-next v1] net: evaluate net.conf.ipvX.all.ignore_routes_with_linkdown
Date: Sat, 17 Oct 2020 14:50:11 +0200 [thread overview]
Message-ID: <20201017125011.2655391-1-vincent@bernat.ch> (raw)
Introduced in 0eeb075fad73, the "ignore_routes_with_linkdown" sysctl
ignores a route whose interface is down. It is provided as a
per-interface sysctl. However, while a "all" variant is exposed, it
was a noop since it was never evaluated. We use the usual "or" logic
for this kind of sysctls.
Tested with:
ip link add type veth # veth0 + veth1
ip link add type veth # veth1 + veth2
ip link set up dev veth0
ip link set up dev veth1 # link-status paired with veth0
ip link set up dev veth2
ip link set up dev veth3 # link-status paired with veth2
# First available path
ip -4 addr add 203.0.113.${uts#H}/24 dev veth0
ip -6 addr add 2001:db8:1::${uts#H}/64 dev veth0
# Second available path
ip -4 addr add 192.0.2.${uts#H}/24 dev veth2
ip -6 addr add 2001:db8:2::${uts#H}/64 dev veth2
# More specific route through first path
ip -4 route add 198.51.100.0/25 via 203.0.113.254 # via veth0
ip -6 route add 2001:db8:3::/56 via 2001:db8:1::ff # via veth0
# Less specific route through second path
ip -4 route add 198.51.100.0/24 via 192.0.2.254 # via veth2
ip -6 route add 2001:db8:3::/48 via 2001:db8:2::ff # via veth2
# H1: enable on "all"
# H2: enable on "veth0"
for v in ipv4 ipv6; do
case $uts in
H1)
sysctl -qw net.${v}.conf.all.ignore_routes_with_linkdown=1
;;
H2)
sysctl -qw net.${v}.conf.veth0.ignore_routes_with_linkdown=1
;;
esac
done
set -xe
# When veth0 is up, best route is through veth0
ip -o route get 198.51.100.1 | grep -Fw veth0
ip -o route get 2001:db8:3::1 | grep -Fw veth0
# When veth0 is down, best route should be through veth2 on H1/H2,
# but on veth0 on H2
ip link set down dev veth1 # down veth0
ip route show
[ $uts != H3 ] || ip -o route get 198.51.100.1 | grep -Fw veth0
[ $uts != H3 ] || ip -o route get 2001:db8:3::1 | grep -Fw veth0
[ $uts = H3 ] || ip -o route get 198.51.100.1 | grep -Fw veth2
[ $uts = H3 ] || ip -o route get 2001:db8:3::1 | grep -Fw veth2
Without this patch, the two last lines would fail on H1 (the one using
the "all" sysctl). With the patch, everything succeeds as expected.
Also document the sysctl in `ip-sysctl.rst`.
Fixes: 0eeb075fad73 ("net: ipv4 sysctl option to ignore routes when nexthop link is down")
Signed-off-by: Vincent Bernat <vincent@bernat.ch>
---
Documentation/networking/ip-sysctl.rst | 3 +++
include/linux/inetdevice.h | 2 +-
2 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst
index 837d51f9e1fa..fb6e4658fd4f 100644
--- a/Documentation/networking/ip-sysctl.rst
+++ b/Documentation/networking/ip-sysctl.rst
@@ -1552,6 +1552,9 @@ igmpv3_unsolicited_report_interval - INTEGER
Default: 1000 (1 seconds)
+ignore_routes_with_linkdown - BOOLEAN
+ Ignore routes whose link is down when performing a FIB lookup.
+
promote_secondaries - BOOLEAN
When a primary IP address is removed from this interface
promote a corresponding secondary IP address instead of
diff --git a/include/linux/inetdevice.h b/include/linux/inetdevice.h
index 3515ca64e638..3bbcddd22df8 100644
--- a/include/linux/inetdevice.h
+++ b/include/linux/inetdevice.h
@@ -126,7 +126,7 @@ static inline void ipv4_devconf_setall(struct in_device *in_dev)
IN_DEV_ORCONF((in_dev), ACCEPT_REDIRECTS)))
#define IN_DEV_IGNORE_ROUTES_WITH_LINKDOWN(in_dev) \
- IN_DEV_CONF_GET((in_dev), IGNORE_ROUTES_WITH_LINKDOWN)
+ IN_DEV_ORCONF((in_dev), IGNORE_ROUTES_WITH_LINKDOWN)
#define IN_DEV_ARPFILTER(in_dev) IN_DEV_ORCONF((in_dev), ARPFILTER)
#define IN_DEV_ARP_ACCEPT(in_dev) IN_DEV_ORCONF((in_dev), ARP_ACCEPT)
--
2.28.0
next reply other threads:[~2020-10-17 13:04 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-17 12:50 Vincent Bernat [this message]
2020-10-20 0:53 ` [PATCH net-next v1] net: evaluate net.conf.ipvX.all.ignore_routes_with_linkdown Jakub Kicinski
2020-10-20 2:56 ` David Ahern
2020-10-20 3:15 ` Jakub Kicinski
2020-10-20 6:20 ` Vincent Bernat
2020-10-20 22:55 ` Jakub Kicinski
2020-10-20 2:57 ` David Ahern
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