linux/include
Ido Schimmel 3c71006d15 ipv4: fib_rules: Check if rule is a default rule
Currently, when non-default (custom) FIB rules are used, devices capable
of layer 3 offloading flush their tables and let the kernel do the
forwarding instead.

When these devices' drivers are loaded they register to the FIB
notification chain, which lets them know about the existence of any
custom FIB rules. This is done by sending a RULE_ADD notification based
on the value of 'net->ipv4.fib_has_custom_rules'.

This approach is problematic when VRF offload is taken into account, as
upon the creation of the first VRF netdev, a l3mdev rule is programmed
to direct skbs to the VRF's table.

Instead of merely reading the above value and sending a single RULE_ADD
notification, we should iterate over all the FIB rules and send a
detailed notification for each, thereby allowing offloading drivers to
sanitize the rules they don't support and potentially flush their
tables.

While l3mdev rules are uniquely marked, the default rules are not.
Therefore, when they are being notified they might invoke offloading
drivers to unnecessarily flush their tables.

Solve this by adding an helper to check if a FIB rule is a default rule.
Namely, its selector should match all packets and its action should
point to the local, main or default tables.

As noted by David Ahern, uniquely marking the default rules is
insufficient. When using VRFs, it's common to avoid false hits by moving
the rule for the local table to just before the main table:

Default configuration:
$ ip rule show
0:      from all lookup local
32766:  from all lookup main
32767:  from all lookup default

Common configuration with VRFs:
$ ip rule show
1000:   from all lookup [l3mdev-table]
32765:  from all lookup local
32766:  from all lookup main
32767:  from all lookup default

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-03-16 10:18:33 -07:00
..
acpi
asm-generic mm: convert generic code to 5-level paging 2017-03-09 11:48:47 -08:00
clocksource
crypto net: Work around lockdep limitation in sockets that use sockets 2017-03-09 18:23:27 -08:00
drm sched/headers: Prepare to remove the <linux/mm_types.h> dependency from <linux/sched.h> 2017-03-02 08:42:37 +01:00
dt-bindings scripts/spelling.txt: add "overide" pattern and fix typo instances 2017-03-09 17:01:09 -08:00
keys KEYS: Differentiate uses of rcu_dereference_key() and user_key_payload() 2017-03-02 10:09:00 +11:00
kvm
linux mqprio: Modify mqprio to pass user parameters via ndo_setup_tc. 2017-03-15 15:20:27 -07:00
math-emu
media media fixes for v4.11-rc2 2017-03-09 15:50:56 -08:00
memory
misc
net ipv4: fib_rules: Check if rule is a default rule 2017-03-16 10:18:33 -07:00
pcmcia
ras
rdma sched/headers: Prepare to remove <linux/cred.h> inclusion from <linux/sched.h> 2017-03-02 08:42:31 +01:00
rxrpc
scsi scsi: mpt3sas: Avoid sleeping in interrupt context 2017-03-01 21:52:13 -05:00
soc
sound sched/headers: Prepare to remove spurious <linux/sched.h> inclusion dependencies 2017-03-02 08:42:41 +01:00
target Merge branch 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2017-03-03 10:16:38 -08:00
trace There was some breakage with the changes for jump labels in the 4.11 merge 2017-03-07 09:37:28 -08:00
uapi mqprio: Change handling of hw u8 to allow for multiple hardware offload modes 2017-03-15 15:20:27 -07:00
video
xen Merge branch 'stable/for-linus-4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/swiotlb 2017-03-07 10:23:17 -08:00
Kbuild