linux-toradex.git/include/uapi/linux/if_link.h, branch v4.12

xdp: refine xdp api with regards to generic xdp

2017-05-12T01:30:57+00:00

While working on the iproute2 generic XDP frontend, I noticed that
as of right now it's possible to have native *and* generic XDP
programs loaded both at the same time for the case when a driver
supports native XDP.

The intended model for generic XDP from b5cdae3291f7 ("net: Generic
XDP") is, however, that only one out of the two can be present at
once which is also indicated as such in the XDP netlink dump part.
The main rationale for generic XDP is to ease accessibility (in
case a driver does not yet have XDP support) and to generically
provide a semantical model as an example for driver developers
wanting to add XDP support. The generic XDP option for an XDP
aware driver can still be useful for comparing and testing both
implementations.

However, it is not intended to have a second XDP processing stage
or layer with exactly the same functionality of the first native
stage. Only reason could be to have a partial fallback for future
XDP features that are not supported yet in the native implementation
and we probably also shouldn't strive for such fallback and instead
encourage native feature support in the first place. Given there's
currently no such fallback issue or use case, lets not go there yet
if we don't need to.

Therefore, change semantics for loading XDP and bail out if the
user tries to load a generic XDP program when a native one is
present and vice versa. Another alternative to bailing out would
be to handle the transition from one flavor to another gracefully,
but that would require to bring the device down, exchange both
types of programs, and bring it up again in order to avoid a tiny
window where a packet could hit both hooks. Given this complicates
the logic for just a debugging feature in the native case, I went
with the simpler variant.

For the dump, remove IFLA_XDP_FLAGS that was added with b5cdae3291f7
and reuse IFLA_XDP_ATTACHED for indicating the mode. Dumping all
or just a subset of flags that were used for loading the XDP prog
is suboptimal in the long run since not all flags are useful for
dumping and if we start to reuse the same flag definitions for
load and dump, then we'll waste bit space. What we really just
want is to dump the mode for now.

Current IFLA_XDP_ATTACHED semantics are: nothing was installed (0),
a program is running at the native driver layer (1). Thus, add a
mode that says that a program is running at generic XDP layer (2).
Applications will handle this fine in that older binaries will
just indicate that something is attached at XDP layer, effectively
this is similar to IFLA_XDP_FLAGS attr that we would have had
modulo the redundancy.

Signed-off-by: Daniel Borkmann 
Acked-by: Alexei Starovoitov 
Signed-off-by: David S. Miller

xdp: add flag to enforce driver mode

2017-05-12T01:30:57+00:00

After commit b5cdae3291f7 ("net: Generic XDP") we automatically fall
back to a generic XDP variant if the driver does not support native
XDP. Allow for an option where the user can specify that always the
native XDP variant should be selected and in case it's not supported
by a driver, just bail out.

Signed-off-by: Daniel Borkmann 
Acked-by: Alexei Starovoitov 
Signed-off-by: David S. Miller

bridge: add per-port broadcast flood flag

2017-04-27T20:34:29+00:00

Support for l2 multicast flood control was added in commit b6cb5ac8331b
("net: bridge: add per-port multicast flood flag"). It allows broadcast
as it was introduced specifically for unknown multicast flood control.
But as broadcast is a special case of multicast, this may also need to
be disabled. For this purpose, introduce a flag to disable the flooding
of received l2 broadcasts. This approach is backwards compatible and
provides flexibility in filtering for the desired packet types.

Cc: Nikolay Aleksandrov 
Signed-off-by: Mike Manning 
Reviewed-by: Nikolay Aleksandrov 
Signed-off-by: David S. Miller

net: Generic XDP

2017-04-25T17:33:49+00:00

This provides a generic SKB based non-optimized XDP path which is used
if either the driver lacks a specific XDP implementation, or the user
requests it via a new IFLA_XDP_FLAGS value named XDP_FLAGS_SKB_MODE.

It is arguable that perhaps I should have required something like
this as part of the initial XDP feature merge.

I believe this is critical for two reasons:

1) Accessibility.  More people can play with XDP with less
   dependencies.  Yes I know we have XDP support in virtio_net, but
   that just creates another depedency for learning how to use this
   facility.

   I wrote this to make life easier for the XDP newbies.

2) As a model for what the expected semantics are.  If there is a pure
   generic core implementation, it serves as a semantic example for
   driver folks adding XDP support.

One thing I have not tried to address here is the issue of
XDP_PACKET_HEADROOM, thanks to Daniel for spotting that.  It seems
incredibly expensive to do a skb_cow(skb, XDP_PACKET_HEADROOM) or
whatever even if the XDP program doesn't try to push headers at all.
I think we really need the verifier to somehow propagate whether
certain XDP helpers are used or not.

v5:
 - Handle both negative and positive offset after running prog
 - Fix mac length in XDP_TX case (Alexei)
 - Use rcu_dereference_protected() in free_netdev (kbuild test robot)

v4:
 - Fix MAC header adjustmnet before calling prog (David Ahern)
 - Disable LRO when generic XDP is installed (Michael Chan)
 - Bypass qdisc et al. on XDP_TX and record the event (Alexei)
 - Do not perform generic XDP on reinjected packets (DaveM)

v3:
 - Make sure XDP program sees packet at MAC header, push back MAC
   header if we do XDP_TX.  (Alexei)
 - Elide GRO when generic XDP is in use.  (Alexei)
 - Add XDP_FLAG_SKB_MODE flag which the user can use to request generic
   XDP even if the driver has an XDP implementation.  (Alexei)
 - Report whether SKB mode is in use in rtnl_xdp_fill() via XDP_FLAGS
   attribute.  (Daniel)

v2:
 - Add some "fall through" comments in switch statements based
   upon feedback from Andrew Lunn
 - Use RCU for generic xdp_prog, thanks to Johannes Berg.

Tested-by: Andy Gospodarek 
Tested-by: Jesper Dangaard Brouer 
Tested-by: David Ahern 
Signed-off-by: David S. Miller

Revert "rtnl: Add support for netdev event to link messages"

2017-04-09T21:45:21+00:00

This reverts commit def12888c161e6fec0702e5ec9c3962846e3a21d.

As per discussion between Roopa Prabhu and David Ahern, it is
advisable that we instead have the code collect the setlink triggered
events into a bitmask emitted in the IFLA_EVENT netlink attribute.

Signed-off-by: David S. Miller

rtnl: Add support for netdev event to link messages

2017-04-05T15:14:14+00:00

When netdev events happen, a rtnetlink_event() handler will send
messages for every event in it's white list.  These messages contain
current information about a particular device, but they do not include
the iformation about which event just happened.  The consumer of
the message has to try to infer this information.  In some cases
(ex: NETDEV_NOTIFY_PEERS), that is not possible.

This patch adds a new extension to RTM_NEWLINK message called IFLA_EVENT
that would have an encoding of the which event triggered this
message.  This would allow the the message consumer to easily determine
if it is interested in a particular event or not.

Signed-off-by: Vladislav Yasevich 
Signed-off-by: David S. Miller

gtp: support SGSN-side tunnels

2017-03-26T03:11:19+00:00

The GTP-tunnel driver is explicitly GGSN-side as it searches for PDP
contexts based on the incoming packets _destination_ address.  If we
want to place ourselves on the SGSN side of the  tunnel, then we want
to be identifying PDP contexts based on _source_ address.

Let it be noted that in a "real" configuration this module would never
be used:  the SGSN normally does not see IP packets as input.  The
justification for this functionality is for PGW load-testing applications
where the input to the SGSN is locally generally IP traffic.

This patch adds a "role" argument at GTP-link creation time to specify
whether we are on the GGSN or SGSN side of the tunnel; this flag is then
used to determine which part of the IP packet to use in determining
the PDP context.

Signed-off-by: Jonas Bonn 
Acked-by: Pablo Neira Ayuso 
Acked-by: Harald Welte 
Signed-off-by: David S. Miller

bridge: uapi: add per vlan tunnel info

2017-02-03T20:21:21+00:00

New nested netlink attribute to associate tunnel info per vlan.
This is used by bridge driver to send tunnel metadata to
bridge ports in vlan tunnel mode. This patch also adds new per
port flag IFLA_BRPORT_VLAN_TUNNEL to enable vlan tunnel mode.
off by default.

One example use for this is a vxlan bridging gateway or vtep
which maps vlans to vn-segments (or vnis). User can configure
per-vlan tunnel information which the bridge driver can use
to bridge vlan into the corresponding vn-segment.

Signed-off-by: Roopa Prabhu 
Signed-off-by: David S. Miller

bridge: multicast to unicast

2017-01-24T17:39:52+00:00

Implements an optional, per bridge port flag and feature to deliver
multicast packets to any host on the according port via unicast
individually. This is done by copying the packet per host and
changing the multicast destination MAC to a unicast one accordingly.

multicast-to-unicast works on top of the multicast snooping feature of
the bridge. Which means unicast copies are only delivered to hosts which
are interested in it and signalized this via IGMP/MLD reports
previously.

This feature is intended for interface types which have a more reliable
and/or efficient way to deliver unicast packets than broadcast ones
(e.g. wifi).

However, it should only be enabled on interfaces where no IGMPv2/MLDv1
report suppression takes place. This feature is disabled by default.

The initial patch and idea is from Felix Fietkau.

Signed-off-by: Felix Fietkau 
[linus.luessing@c0d3.blue: various bug + style fixes, commit message]
Signed-off-by: Linus Lüssing 
Reviewed-by: Nikolay Aleksandrov 
Signed-off-by: David S. Miller

net: AF-specific RTM_GETSTATS attributes

2017-01-17T19:38:43+00:00

Add the functionality for including address-family-specific per-link
stats in RTM_GETSTATS messages. This is done through adding a new
IFLA_STATS_AF_SPEC attribute under which address family attributes are
nested and then the AF-specific attributes can be further nested. This
follows the model of IFLA_AF_SPEC on RTM_*LINK messages and it has the
advantage of presenting an easily extended hierarchy. The rtnl_af_ops
structure is extended to provide AFs with the opportunity to fill and
provide the size of their stats attributes.

One alternative would have been to provide AFs with the ability to add
attributes directly into the RTM_GETSTATS message without a nested
hierarchy. I discounted this approach as it increases the rate at
which the 32 attribute number space is used up and it makes
implementation a little more tricky for stats dump resuming (at the
moment the order in which attributes are added to the message has to
match the numeric order of the attributes).

Another alternative would have been to register per-AF RTM_GETSTATS
handlers. I discounted this approach as I perceived a common use-case
to be getting all the stats for an interface and this approach would
necessitate multiple requests/dumps to retrieve them all.

Signed-off-by: Robert Shearman 
Acked-by: Roopa Prabhu 
Signed-off-by: David S. Miller