[PATCH net-next 0/3] l2tp: sanitise MTU handling on sessions

[Guillaume Nault <g.nault@alphalink.fr>]

Most of the code handling sessions' MTU has no effect. The ->mtu field
in struct l2tp_session might be used at session creation time, but
neither PPP nor Ethernet pseudo-wires take updates into account.

L2TP sessions don't have a concept of MTU, which is the reason why
->mtu is mostly ignored. MTU should remain a network device thing.
Therefore this patch set does not try to propagate/update ->mtu to/from
the device. That would complicate the code unnecessarily. Instead this
field and the associated ioctl commands and netlink attributes are
removed.

Patch #1 defines l2tp_tunnel_dst_mtu() in order to simplify the
following patches. Then patches #2 and #3 remove MTU handling from PPP
and Ethernet pseudo-wires respectively.

Guillaume Nault (3):
  l2tp: define l2tp_tunnel_dst_mtu()
  l2tp: simplify MTU handling in l2tp_ppp
  l2tp: ignore L2TP_ATTR_MTU

 include/uapi/linux/l2tp.h |  2 +-
 net/l2tp/l2tp_core.c      |  1 -
 net/l2tp/l2tp_core.h      | 20 +++++++++--
 net/l2tp/l2tp_debugfs.c   |  3 +-
 net/l2tp/l2tp_eth.c       | 25 +++++--------
 net/l2tp/l2tp_netlink.c   |  9 +----
 net/l2tp/l2tp_ppp.c       | 74 ++++++++++-----------------------------
 7 files changed, 47 insertions(+), 87 deletions(-)

-- 
2.18.0