linux/net/bridge
Hangbin Liu bd085ef678 net: add bool confirm_neigh parameter for dst_ops.update_pmtu
The MTU update code is supposed to be invoked in response to real
networking events that update the PMTU. In IPv6 PMTU update function
__ip6_rt_update_pmtu() we called dst_confirm_neigh() to update neighbor
confirmed time.

But for tunnel code, it will call pmtu before xmit, like:
  - tnl_update_pmtu()
    - skb_dst_update_pmtu()
      - ip6_rt_update_pmtu()
        - __ip6_rt_update_pmtu()
          - dst_confirm_neigh()

If the tunnel remote dst mac address changed and we still do the neigh
confirm, we will not be able to update neigh cache and ping6 remote
will failed.

So for this ip_tunnel_xmit() case, _EVEN_ if the MTU is changed, we
should not be invoking dst_confirm_neigh() as we have no evidence
of successful two-way communication at this point.

On the other hand it is also important to keep the neigh reachability fresh
for TCP flows, so we cannot remove this dst_confirm_neigh() call.

To fix the issue, we have to add a new bool parameter for dst_ops.update_pmtu
to choose whether we should do neigh update or not. I will add the parameter
in this patch and set all the callers to true to comply with the previous
way, and fix the tunnel code one by one on later patches.

v5: No change.
v4: No change.
v3: Do not remove dst_confirm_neigh, but add a new bool parameter in
    dst_ops.update_pmtu to control whether we should do neighbor confirm.
    Also split the big patch to small ones for each area.
v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu.

Suggested-by: David Miller <davem@davemloft.net>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2019-12-24 22:28:54 -08:00
..
netfilter bridge: ebtables: don't crash when using dnat target in output chains 2019-11-04 20:58:34 +01:00
br_arp_nd_proxy.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
br_device.c net: bridge: deny dev_set_mac_address() when unregistering 2019-12-03 11:21:20 -08:00
br_fdb.c net: bridge: fdb: eliminate extra port state tests from fast-path 2019-11-04 11:15:27 -08:00
br_forward.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
br_if.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
br_input.c net: bridge: fdb: eliminate extra port state tests from fast-path 2019-11-04 11:15:27 -08:00
br_ioctl.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
br_mdb.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net 2019-09-15 14:17:27 +02:00
br_multicast.c net: bridge: mdb: allow add/delete for host-joined groups 2019-08-17 12:36:57 -07:00
br_netfilter_hooks.c netfilter: bridge: make sure to pull arp header in br_nf_forward_arp() 2019-12-09 13:14:06 +01:00
br_netfilter_ipv6.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2019-06-25 01:32:59 +02:00
br_netlink_tunnel.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
br_netlink.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
br_nf_core.c net: add bool confirm_neigh parameter for dst_ops.update_pmtu 2019-12-24 22:28:54 -08:00
br_private_stp.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
br_private_tunnel.h treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
br_private.h net: bridge: fdb: eliminate extra port state tests from fast-path 2019-11-04 11:15:27 -08:00
br_stp_bpdu.c net: bridge: stp: don't cache eth dest pointer before skb pull 2019-07-02 11:53:03 -07:00
br_stp_if.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
br_stp_timer.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
br_stp.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
br_switchdev.c net: bridge: fdb: convert offloaded to use bitops 2019-10-29 18:12:49 -07:00
br_sysfs_br.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
br_sysfs_if.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
br_vlan_tunnel.c treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152 2019-05-30 11:26:32 -07:00
br_vlan.c net: bridge: Populate the pvid flag in br_vlan_get_info 2019-08-31 13:21:19 -07:00
br.c treewide: Use sizeof_field() macro 2019-12-09 10:36:44 -08:00
Kconfig treewide: Add SPDX license identifier - Makefile/Kconfig 2019-05-21 10:50:46 +02:00
Makefile Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2017-11-04 09:26:51 +09:00