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| author | Maciej Żenczykowski <maze@google.com> | 2016-11-04 21:51:54 (GMT) |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-11-09 18:19:32 (GMT) |
| commit | fb56be83e43d0bb0cc9e8c35a6a9cac853231ba2 (patch) | |
| tree | 2df54004541ac2397e6035d9301804b36c3b8ea3 /drivers/net/ethernet | |
| parent | 3023898b7d4aac65987bd2f485cc22390aae6f78 (diff) | |
| download | linux-fb56be83e43d0bb0cc9e8c35a6a9cac853231ba2.tar.xz | |
net-ipv6: on device mtu change do not add mtu to mtu-less routes
Routes can specify an mtu explicitly or inherit the mtu from
the underlying device - this inheritance is implemented in
dst->ops->mtu handlers ip6_mtu() and ip6_blackhole_mtu().
Currently changing the mtu of a device adds mtu explicitly
to routes using that device.
ie.
# ip link set dev lo mtu 65536
# ip -6 route add local 2000::1 dev lo
# ip -6 route get 2000::1
local 2000::1 dev lo table local src ... metric 1024 pref medium
# ip link set dev lo mtu 65535
# ip -6 route get 2000::1
local 2000::1 dev lo table local src ... metric 1024 mtu 65535 pref medium
# ip link set dev lo mtu 65536
# ip -6 route get 2000::1
local 2000::1 dev lo table local src ... metric 1024 mtu 65536 pref medium
# ip -6 route del local 2000::1
After this patch the route entry no longer changes unless it already has an mtu.
There is no need: this inheritance is already done in ip6_mtu()
# ip link set dev lo mtu 65536
# ip -6 route add local 2000::1 dev lo
# ip -6 route add local 2000::2 dev lo mtu 2000
# ip -6 route get 2000::1; ip -6 route get 2000::2
local 2000::1 dev lo table local src ... metric 1024 pref medium
local 2000::2 dev lo table local src ... metric 1024 mtu 2000 pref medium
# ip link set dev lo mtu 65535
# ip -6 route get 2000::1; ip -6 route get 2000::2
local 2000::1 dev lo table local src ... metric 1024 pref medium
local 2000::2 dev lo table local src ... metric 1024 mtu 2000 pref medium
# ip link set dev lo mtu 1501
# ip -6 route get 2000::1; ip -6 route get 2000::2
local 2000::1 dev lo table local src ... metric 1024 pref medium
local 2000::2 dev lo table local src ... metric 1024 mtu 1501 pref medium
# ip link set dev lo mtu 65536
# ip -6 route get 2000::1; ip -6 route get 2000::2
local 2000::1 dev lo table local src ... metric 1024 pref medium
local 2000::2 dev lo table local src ... metric 1024 mtu 65536 pref medium
# ip -6 route del local 2000::1
# ip -6 route del local 2000::2
This is desirable because changing device mtu and then resetting it
to the previous value shouldn't change the user visible routing table.
Signed-off-by: Maciej Żenczykowski <maze@google.com>
CC: Eric Dumazet <edumazet@google.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/ethernet')
0 files changed, 0 insertions, 0 deletions