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author | Vincent Bernat <vincent@bernat.ch> | 2020-11-07 20:35:13 +0100 |
---|---|---|
committer | Jakub Kicinski <kuba@kernel.org> | 2020-11-11 16:41:30 -0800 |
commit | c0c5a60f0f1311bcf08bbe735122096d6326fb5b (patch) | |
tree | 1a4bdc4a623cf156ba396e5f2746bf967b2f1b86 /Documentation/networking/ip-sysctl.rst | |
parent | c079fe2480e40043aeed7c384b7abd805d169a1e (diff) | |
download | linux-stable-c0c5a60f0f1311bcf08bbe735122096d6326fb5b.tar.gz linux-stable-c0c5a60f0f1311bcf08bbe735122096d6326fb5b.tar.bz2 linux-stable-c0c5a60f0f1311bcf08bbe735122096d6326fb5b.zip |
net: evaluate net.ipvX.conf.all.ignore_routes_with_linkdown
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>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'Documentation/networking/ip-sysctl.rst')
-rw-r--r-- | Documentation/networking/ip-sysctl.rst | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/Documentation/networking/ip-sysctl.rst b/Documentation/networking/ip-sysctl.rst index 2aaf40b2d2cd..dd2b12a32b73 100644 --- a/Documentation/networking/ip-sysctl.rst +++ b/Documentation/networking/ip-sysctl.rst @@ -1554,6 +1554,9 @@ 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 |