linux/net/core
Daniel Borkmann d67b9cd28c xdp: refine xdp api with regards to generic xdp
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 b5cdae3291 ("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 b5cdae3291
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 <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-11 21:30:57 -04:00
..
datagram.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2017-05-02 16:40:27 -07:00
dev_addr_lists.c
dev_ioctl.c
dev.c xdp: refine xdp api with regards to generic xdp 2017-05-11 21:30:57 -04:00
devlink.c net/devlink: Add E-Switch encapsulation control 2017-04-22 20:26:37 +03:00
drop_monitor.c drop_monitor: use setup_timer 2017-03-12 23:47:16 -07:00
dst_cache.c net: dst_cache_per_cpu_dst_set() can be static 2016-03-18 17:45:08 -04:00
dst.c net: pending_confirm is not used anymore 2017-02-07 13:07:47 -05:00
ethtool.c net: Add ESP offload features 2017-04-14 10:05:36 +02:00
fib_rules.c fib_rules: fix error return code 2017-04-27 16:35:57 -04:00
filter.c bpf: restore skb->sk before pskb_trim() call 2017-04-30 22:23:16 -04:00
flow_dissector.c flow_dissector: add mpls support (v2) 2017-04-24 14:30:46 -04:00
flow.c flowcache: more "unsigned int" 2017-04-03 19:04:48 -07:00
gen_estimator.c Replace <asm/uaccess.h> with <linux/uaccess.h> globally 2016-12-24 11:46:01 -08:00
gen_stats.c net_sched: gen_estimator: complete rewrite of rate estimators 2016-12-05 15:21:59 -05:00
gro_cells.c net: Generic XDP 2017-04-25 13:33:49 -04:00
hwbm.c net: hwbm: Fix unbalanced spinlock in error case 2016-05-25 12:35:09 -07:00
link_watch.c dev: introduce dev_get_iflink() 2015-04-02 14:04:59 -04:00
lwt_bpf.c netlink: pass extended ACK struct to parsing functions 2017-04-13 13:58:22 -04:00
lwtunnel.c lwtunnel: fix error path in lwtunnel_fill_encap() 2017-04-30 22:41:29 -04:00
Makefile gro_cells: move to net/core/gro_cells.c 2017-02-08 14:38:18 -05:00
neighbour.c net: rtnetlink: plumb extended ack to doit function 2017-04-17 15:35:38 -04:00
net_namespace.c net: Initialise init_net.count to 1 2017-04-30 22:32:16 -04:00
net-procfs.c net: remove NETDEV_TX_LOCKED support 2016-04-26 15:53:05 -04:00
net-sysfs.c net: use net->count to check whether a netns is alive or not 2017-03-13 16:02:27 -07:00
net-sysfs.h
net-traces.c net: IPv6 fib lookup tracepoint 2015-11-22 11:54:10 -05:00
netclassid_cgroup.c cgroup, net_cls: iterate the fds of only the tasks which are being migrated 2017-03-22 10:32:46 -07:00
netevent.c netevent: remove automatic variable in register_netevent_notifier() 2015-05-31 00:03:21 -07:00
netpoll.c netpoll: Check for skb->queue_mapping 2017-04-21 15:45:19 -04:00
netprio_cgroup.c net: break include loop netdevice.h, dsa.h, devlink.h 2017-03-28 22:46:04 -07:00
pktgen.c net-tc: convert tc_verd to integer bitfields 2017-01-08 20:58:52 -05:00
ptp_classifier.c ptp: Change ptp_class to a proper bitmask 2015-11-03 11:08:22 -05:00
request_sock.c ipv4: Namespaceify tcp_max_syn_backlog knob 2016-12-29 11:38:31 -05:00
rtnetlink.c xdp: refine xdp api with regards to generic xdp 2017-05-11 21:30:57 -04:00
scm.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/user.h> 2017-03-02 08:42:29 +01:00
secure_seq.c tcp: randomize timestamps on syncookies 2017-05-05 12:00:11 -04:00
skbuff.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2017-05-02 16:40:27 -07:00
sock_diag.c netlink: extended ACK reporting 2017-04-13 13:58:20 -04:00
sock_reuseport.c soreuseport: use "unsigned int" in __reuseport_alloc() 2017-04-03 19:06:38 -07:00
sock.c treewide: convert PF_MEMALLOC manipulations to new helpers 2017-05-08 17:15:15 -07:00
stream.c sched/headers: Prepare for new header dependencies before moving code to <linux/sched/signal.h> 2017-03-02 08:42:29 +01:00
sysctl_net_core.c Replace 2 jiffies with sysctl netdev_budget_usecs to enable softirq tuning 2017-04-21 13:22:34 -04:00
timestamping.c net: skb_defer_rx_timestamp should check for phydev before setting up classify 2015-07-09 14:17:15 -07:00
tso.c net: tso: add support for IPv6 2015-10-26 22:24:22 -07:00
utils.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2017-05-02 16:40:27 -07:00