I found a serious performance bug in packet schedulers using hrtimers.

sch_htb and sch_fq are definitely impacted by this problem.

We constantly rearm high resolution timers if some packets are throttled
in one (or more) class, and other packets are flying through qdisc on
another (non throttled) class.

hrtimer_start() does not have the mod_timer() trick of doing nothing if
expires value does not change :

	if (timer_pending(timer) &&
            timer->expires == expires)
                return 1;

This issue is particularly visible when multiple cpus can queue/dequeue
packets on the same qdisc, as hrtimer code has to lock a remote base.

I used following fix :

1) Change htb to use qdisc_watchdog_schedule_ns() instead of open-coding
it.

2) Cache watchdog prior expiration. hrtimer might provide this, but I
prefer to not rely on some hrtimer internal.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We saw the following extra refcount release on veth device:

  kernel: [7957821.463992] unregister_netdevice: waiting for mesos50284 to become free. Usage count = -1

Since we heavily use mirred action to redirect packets to veth, I think
this is caused by the following race condition:

CPU0:
tcf_mirred_release(): (in RCU callback)
	struct net_device *dev = rcu_dereference_protected(m->tcfm_dev, 1);

CPU1:
mirred_device_event():
        spin_lock_bh(&mirred_list_lock);
        list_for_each_entry(m, &mirred_list, tcfm_list) {
                if (rcu_access_pointer(m->tcfm_dev) == dev) {
                        dev_put(dev);
                        /* Note : no rcu grace period necessary, as
                         * net_device are already rcu protected.
                         */
                        RCU_INIT_POINTER(m->tcfm_dev, NULL);
                }
        }
        spin_unlock_bh(&mirred_list_lock);

CPU0:
tcf_mirred_release():
        spin_lock_bh(&mirred_list_lock);
        list_del(&m->tcfm_list);
        spin_unlock_bh(&mirred_list_lock);
        if (dev)               // <======== Stil refers to the old m->tcfm_dev
                dev_put(dev);  // <======== dev_put() is called on it again

The action init code path is good because it is impossible to modify
an action that is being removed.

So, fix this by moving everything under the spinlock.

Fixes: 2ee22a90 ("net_sched: act_mirred: remove spinlock in fast path")
Fixes: 6bd00b85 ("act_mirred: fix a race condition on mirred_list")
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Acked-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

memory_usage must be decreased in dequeue_func(), not in
fq_codel_dequeue(), otherwise packets dropped by Codel algo
are missing this decrease.

Also we need to clear memory_usage in fq_codel_reset()

Fixes: 95b58430 ("fq_codel: add memory limitation per queue")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Introduce a new command in ndo_setup_tc() for hardware offloaded
filters, to call the NIC driver, and make it update the statistics.
This will be done before dumping the filter and its statistics.
Signed-off-by: NAmir Vadai <amirva@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Implement the stats_update callback that will be called by NIC drivers
for hardware offloaded filters.
Signed-off-by: NAmir Vadai <amirva@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

On devices that support TC U32 offloads, this flag enables a filter to be
added only to HW. skip-sw and skip-hw are mutually exclusive flags. By
default without any flags, the filter is added to both HW and SW, but no
error checks are done in case of failure to add to HW. With skip-sw,
failure to add to HW is treated as an error.

Here is a sample script that adds 2 filters, one with skip-sw and the other
with skip-hw flag.

   # add ingress qdisc
   tc qdisc add dev p4p1 ingress

   # enable hw tc offload.
   ethtool -K p4p1 hw-tc-offload on

   # add u32 filter with skip-sw flag.
   tc filter add dev p4p1 parent ffff: protocol ip prio 99 \
      handle 800:0:1 u32 ht 800: flowid 800:1 \
      skip-sw \
      match ip src 192.168.1.0/24 \
      action drop

   # add u32 filter with skip-hw flag.
   tc filter add dev p4p1 parent ffff: protocol ip prio 99 \
      handle 800:0:2 u32 ht 800: flowid 800:2 \
      skip-hw \
      match ip src 192.168.2.0/24 \
      action drop
Signed-off-by: NSridhar Samudrala <sridhar.samudrala@intel.com>
Acked-by: NJohn Fastabend <john.r.fastabend@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The process below was broken and is fixed with this patch.

//add an ife action and give it an instance id of 1
sudo tc actions add action ife encode \
type 0xDEAD allow mark dst 02:15:15:15:15:15 index 1

//create a filter which binds to ife action id 1
sudo tc filter add dev $DEV parent ffff: protocol ip prio 1 u32\
match ip dst 17.0.0.1/32 flowid 1:11 action ife index 1

Message before fix was:
RTNETLINK answers: Invalid argument
We have an error talking to the kernel
Signed-off-by: NJamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The process below was broken and is fixed with this patch.

//add a skbedit action and give it an instance id of 1
sudo tc actions add action skbedit mark 10 index 1
//create a filter which binds to skbedit action id 1
sudo tc filter add dev $DEV parent ffff: protocol ip prio 1 u32\
match ip dst 17.0.0.1/32 flowid 1:10 action skbedit index 1

Message before fix was:
RTNETLINK answers: Invalid argument
We have an error talking to the kernel
Signed-off-by: NJamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The process below was broken and is fixed with this patch.

//add a simple action and give it an instance id of 1
sudo tc actions add action simple sdata "foobar" index 1
//create a filter which binds to simple action id 1
sudo tc filter add dev $DEV parent ffff: protocol ip prio 1 u32\
match ip dst 17.0.0.1/32 flowid 1:10 action simple index 1

Message before fix was:
RTNETLINK answers: Invalid argument
We have an error talking to the kernel
Signed-off-by: NJamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The process below was broken and is fixed with this patch.

//add an mirred action and give it an instance id of 1
sudo tc actions add action mirred egress mirror dev $MDEV  index 1
//create a filter which binds to mirred action id 1
sudo tc filter add dev $DEV parent ffff: protocol ip prio 1 u32\
match ip dst 17.0.0.1/32 flowid 1:10 action mirred index 1

Message before bug fix was:
RTNETLINK answers: Invalid argument
We have an error talking to the kernel
Signed-off-by: NJamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This was broken and is fixed with this patch.

//add an ipt action and give it an instance id of 1
sudo tc actions add action ipt -j mark --set-mark 2 index 1
//create a filter which binds to ipt action id 1
sudo tc filter add dev $DEV parent ffff: protocol ip prio 1 u32\
match ip dst 17.0.0.1/32 flowid 1:10 action ipt index 1

Message before bug fix was:
RTNETLINK answers: Invalid argument
We have an error talking to the kernel
Signed-off-by: NJamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Late vlan action binding was broken and is fixed with this patch.

//add a vlan action to pop and give it an instance id of 1
sudo tc actions add action vlan pop index 1
//create filter which binds to vlan action id 1
sudo tc filter add dev $DEV parent ffff: protocol ip prio 1 u32 \
match ip dst 17.0.0.1/32 flowid 1:1 action vlan index 1

current message(before bug fix) was:
RTNETLINK answers: Invalid argument
We have an error talking to the kernel
Signed-off-by: NJamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

On small embedded routers, one wants to control maximal amount of
memory used by fq_codel, instead of controlling number of packets or
bytes, since GRO/TSO make these not practical.

Assuming skb->truesize is accurate, we have to keep track of
skb->truesize sum for skbs in queue.

This patch adds a new TCA_FQ_CODEL_MEMORY_LIMIT attribute.

I chose a default value of 32 MBytes, which looks reasonable even
for heavy duty usages. (Prior fq_codel users should not be hurt
when they upgrade their kernels)

Two fields are added to tc_fq_codel_qd_stats to report :
 - Current memory usage
 - Number of drops caused by memory limits

# tc qd replace dev eth1 root est 1sec 4sec fq_codel memory_limit 4M
..
# tc -s -d qd sh dev eth1
qdisc fq_codel 8008: root refcnt 257 limit 10240p flows 1024
 quantum 1514 target 5.0ms interval 100.0ms memory_limit 4Mb ecn
 Sent 2083566791363 bytes 1376214889 pkt (dropped 4994406, overlimits 0
requeues 21705223)
 rate 9841Mbit 812549pps backlog 3906120b 376p requeues 21705223
  maxpacket 68130 drop_overlimit 4994406 new_flow_count 28855414
  ecn_mark 0 memory_used 4190048 drop_overmemory 4994406
  new_flows_len 1 old_flows_len 177
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Dave Täht <dave.taht@gmail.com>
Cc: Sebastian Möller <moeller0@gmx.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

allow cls_bpf and act_bpf programs access skb->data and skb->data_end pointers.
The bpf helpers that change skb->data need to update data_end pointer as well.
The verifier checks that programs always reload data, data_end pointers
after calls to such bpf helpers.
We cannot add 'data_end' pointer to struct qdisc_skb_cb directly,
since it's embedded as-is by infiniband ipoib, so wrapper struct is needed.
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

previous patches removed all direct accesses to dev->trans_start,
so change the netif_trans_update helper to update trans_start of
netdev queue 0 instead and then remove trans_start from struct net_device.

AFAICS a lot of the netif_trans_update() invocations are now useless
because they occur in ndo_start_xmit and driver doesn't set LLTX
(i.e. stack already took care of the update).

As I can't test any of them it seems better to just leave them alone.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Replace all trans_start updates with netif_trans_update helper.
change was done via spatch:

struct net_device *d;
@@
- d->trans_start = jiffies
+ netif_trans_update(d)

Compile tested only.

Cc: user-mode-linux-devel@lists.sourceforge.net
Cc: linux-xtensa@linux-xtensa.org
Cc: linux1394-devel@lists.sourceforge.net
Cc: linux-rdma@vger.kernel.org
Cc: netdev@vger.kernel.org
Cc: MPT-FusionLinux.pdl@broadcom.com
Cc: linux-scsi@vger.kernel.org
Cc: linux-can@vger.kernel.org
Cc: linux-parisc@vger.kernel.org
Cc: linux-omap@vger.kernel.org
Cc: linux-hams@vger.kernel.org
Cc: linux-usb@vger.kernel.org
Cc: linux-wireless@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: devel@driverdev.osuosl.org
Cc: b.a.t.m.a.n@lists.open-mesh.org
Cc: linux-bluetooth@vger.kernel.org
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Acked-by: NFelipe Balbi <felipe.balbi@linux.intel.com>
Acked-by: NMugunthan V N <mugunthanvnm@ti.com>
Acked-by: NAntonio Quartulli <a@unstable.cc>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In presence of inelastic flows and stress, we can call
fq_codel_drop() for every packet entering fq_codel qdisc.

fq_codel_drop() is quite expensive, as it does a linear scan
of 4 KB of memory to find a fat flow.
Once found, it drops the oldest packet of this flow.

Instead of dropping a single packet, try to drop 50% of the backlog
of this fat flow, with a configurable limit of 64 packets per round.

TCA_FQ_CODEL_DROP_BATCH_SIZE is the new attribute to make this
limit configurable.

With this strategy the 4 KB search is amortized to a single cache line
per drop [1], so fq_codel_drop() no longer appears at the top of kernel
profile in presence of few inelastic flows.

[1] Assuming a 64byte cache line, and 1024 buckets
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: NDave Taht <dave.taht@gmail.com>
Cc: Jonathan Morton <chromatix99@gmail.com>
Acked-by: NJesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Dave Taht
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This was recently reported to me, and reproduced on the latest net kernel,
when attempting to run netperf from a host that had a netem qdisc attached
to the egress interface:

[  788.073771] ---------------------[ cut here ]---------------------------
[  788.096716] WARNING: at net/core/dev.c:2253 skb_warn_bad_offload+0xcd/0xda()
[  788.129521] bnx2: caps=(0x00000001801949b3, 0x0000000000000000) len=2962
data_len=0 gso_size=1448 gso_type=1 ip_summed=3
[  788.182150] Modules linked in: sch_netem kvm_amd kvm crc32_pclmul ipmi_ssif
ghash_clmulni_intel sp5100_tco amd64_edac_mod aesni_intel lrw gf128mul
glue_helper ablk_helper edac_mce_amd cryptd pcspkr sg edac_core hpilo ipmi_si
i2c_piix4 k10temp fam15h_power hpwdt ipmi_msghandler shpchp acpi_power_meter
pcc_cpufreq nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs libcrc32c
sd_mod crc_t10dif crct10dif_generic mgag200 syscopyarea sysfillrect sysimgblt
i2c_algo_bit drm_kms_helper ahci ata_generic pata_acpi ttm libahci
crct10dif_pclmul pata_atiixp tg3 libata crct10dif_common drm crc32c_intel ptp
serio_raw bnx2 r8169 hpsa pps_core i2c_core mii dm_mirror dm_region_hash dm_log
dm_mod
[  788.465294] CPU: 16 PID: 0 Comm: swapper/16 Tainted: G        W
------------   3.10.0-327.el7.x86_64 #1
[  788.511521] Hardware name: HP ProLiant DL385p Gen8, BIOS A28 12/17/2012
[  788.542260]  ffff880437c036b8 f7afc56532a53db9 ffff880437c03670
ffffffff816351f1
[  788.576332]  ffff880437c036a8 ffffffff8107b200 ffff880633e74200
ffff880231674000
[  788.611943]  0000000000000001 0000000000000003 0000000000000000
ffff880437c03710
[  788.647241] Call Trace:
[  788.658817]  <IRQ>  [<ffffffff816351f1>] dump_stack+0x19/0x1b
[  788.686193]  [<ffffffff8107b200>] warn_slowpath_common+0x70/0xb0
[  788.713803]  [<ffffffff8107b29c>] warn_slowpath_fmt+0x5c/0x80
[  788.741314]  [<ffffffff812f92f3>] ? ___ratelimit+0x93/0x100
[  788.767018]  [<ffffffff81637f49>] skb_warn_bad_offload+0xcd/0xda
[  788.796117]  [<ffffffff8152950c>] skb_checksum_help+0x17c/0x190
[  788.823392]  [<ffffffffa01463a1>] netem_enqueue+0x741/0x7c0 [sch_netem]
[  788.854487]  [<ffffffff8152cb58>] dev_queue_xmit+0x2a8/0x570
[  788.880870]  [<ffffffff8156ae1d>] ip_finish_output+0x53d/0x7d0
...

The problem occurs because netem is not prepared to handle GSO packets (as it
uses skb_checksum_help in its enqueue path, which cannot manipulate these
frames).

The solution I think is to simply segment the skb in a simmilar fashion to the
way we do in __dev_queue_xmit (via validate_xmit_skb), with some minor changes.
When we decide to corrupt an skb, if the frame is GSO, we segment it, corrupt
the first segment, and enqueue the remaining ones.

tested successfully by myself on the latest net kernel, to which this applies
Signed-off-by: NNeil Horman <nhorman@tuxdriver.com>
CC: Jamal Hadi Salim <jhs@mojatatu.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: netem@lists.linux-foundation.org
CC: eric.dumazet@gmail.com
CC: stephen@networkplumber.org
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

No more users in the tree, remove NETDEV_TX_LOCKED support.
Adds another hole in softnet_stats struct, but better than keeping
the unused collision counter around.
Signed-off-by: NFlorian Westphal <fw@strlen.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It was impossible to include codel.h for the
purpose of having access to codel_params or
codel_vars structure definitions and using them
for embedding in other more complex structures.

This splits allows codel.h itself to be treated
like any other header file while codel_qdisc.h and
codel_impl.h contain function definitions with
logic that was previously in codel.h.

This copies over copyrights and doesn't involve
code changes other than adding a few additional
include directives to net/sched/sch*codel.c.
Signed-off-by: NMichal Kazior <michal.kazior@tieto.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This strips out qdisc specific bits from the code
and makes it slightly more reusable. Codel will be
used by wireless/mac80211 in the future.
Signed-off-by: NMichal Kazior <michal.kazior@tieto.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

A failure in validate_xmit_skb_list() triggered an unconditional call
to dev_requeue_skb with skb=NULL. This slowly grows the queue
discipline's qlen count until all traffic through the queue stops.

We take the optimistic approach and continue running the queue after a
failure since it is unknown if later packets also will fail in the
validate path.

Fixes: 55a93b3e ("qdisc: validate skb without holding lock")
Signed-off-by: NLars Persson <larper@axis.com>
Acked-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The meta_type_ops structures are never modified, so declare them as const.

Done with the help of Coccinelle.
Signed-off-by: NJulia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There are two issues with the current code. First one is that we need
to set res->class to 0 in case we use non-default classid matching.

This is important for the case where cls_bpf was initially set up with
an optional binding to a default class with tcf_bind_filter(), where
the underlying qdisc implements bind_tcf() that fills res->class and
tests for it later on when doing the classification. Convention for
these cases is that after tc_classify() was called, such qdiscs (atm,
drr, qfq, cbq, hfsc, htb) first test class, and if 0, then they lookup
based on classid.

Second, there's a bug with da mode, where res->classid is only assigned
a 16 bit minor, but it needs to expand to the full 32 bit major/minor
combination instead, therefore we need to expand with the bound major.
This is fine as classes belonging to a classful qdisc must share the
same major.

Fixes: 045efa82 ("cls_bpf: introduce integrated actions")
Signed-off-by: NDaniel Borkmann <daniel@iogearbox.net>
Acked-by: NAlexei Starovoitov <ast@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Cast pointer to unsigned long instead of u64, to fix compilation warning
on 32 bit arch, spotted by 0day build.

Fixes: 5b33f488 ("net/flower: Introduce hardware offload support")
Signed-off-by: NAmir Vadai <amir@vadai.me>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This patch is based on a patch made by John Fastabend.
It adds support for offloading cls_flower.
when NETIF_F_HW_TC is on:
  flags = 0       => Rule will be processed twice - by hardware, and if
                     still relevant, by software.
  flags = SKIP_HW => Rull will be processed by software only

If hardware fail/not capabale to apply the rule, operation will NOT
fail. Filter will be processed by SW only.
Acked-by: NJiri Pirko <jiri@mellanox.com>
Suggested-by: NJohn Fastabend <john.r.fastabend@intel.com>
Signed-off-by: NAmir Vadai <amir@vadai.me>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This fix is for dsmark similar to commit 3557619f
("net_sched: prio: use qdisc_dequeue_peeked")
and makes use of qdisc_dequeue_peeked() instead of direct dequeue() call.

First time, wrr peeks dsmark, which will then peek into sfq.
sfq dequeues an skb and it's stored in sch->gso_skb.
Next time, wrr tries to dequeue from dsmark, which will call sfq dequeue
directly. This results skipping the previously peeked skb.

So changed dsmark dequeue to call qdisc_dequeue_peeked() instead to use
peeked skb if exists.
Signed-off-by: NKyeong Yoo <kyeong.yoo@alliedtelesis.co.nz>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Before calling the destroy() or target() callbacks, the family parameter
field has to be initialized. Otherwise at least the LOG target will
refuse to work and upon removal oops the kernel.

Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NPhil Sutter <phil@nwl.cc>
Acked-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Acked-by: NJamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Some devices declare a high number of TX queues, then set a much
lower real_num_tx_queues

This cause setups using fq_codel, sfq or fq as the default qdisc to consume
more memory than really needed.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

  CC [M]  net/sched/sch_mqprio.o
net/sched/sch_mqprio.c: In function ?mqprio_init?:
net/sched/sch_mqprio.c:145: error: unknown field ?tc? specified in initializer
net/sched/sch_mqprio.c:145: warning: missing braces around initializer
net/sched/sch_mqprio.c:145: warning: (near initialization for ?tc.<anonymous>?)
make[2]: *** [net/sched/sch_mqprio.o] Error 1
make[1]: *** [net/sched] Error 2
make: *** [net] Error 2

Several people reported this, surround the unnamed union
member initialization with braces to fix.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

After commit 52bd2d62 ("net: better skb->sender_cpu and skb->napi_id cohabitation")
skb_sender_cpu_clear() becomes empty and can be removed.

Cc: Eric Dumazet <edumazet@google.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

    Example usage:
    Set the skb priority using skbedit then allow it to be encoded

    sudo tc qdisc add dev $ETH root handle 1: prio
    sudo tc filter add dev $ETH parent 1: protocol ip prio 10 \
    u32 match ip protocol 1 0xff flowid 1:2 \
    action skbedit prio 17 \
    action ife encode \
    allow prio \
    dst 02:15:15:15:15:15

    Note: You dont need the skbedit action if you are already encoding the
    skb priority earlier. A zero skb priority will not be sent

    Alternative hard code static priority of decimal 33 (unlike skbedit)
    then mark of 0x12 every time the filter matches

    sudo $TC filter add dev $ETH parent 1: protocol ip prio 10 \
    u32 match ip protocol 1 0xff flowid 1:2 \
    action ife encode \
    type 0xDEAD \
    use prio 33 \
    use mark 0x12 \
    dst 02:15:15:15:15:15
Signed-off-by: NJamal Hadi Salim <jhs@mojatatu.com>
Acked-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Example usage:
Set the skb using skbedit then allow it to be encoded

sudo tc qdisc add dev $ETH root handle 1: prio
sudo tc filter add dev $ETH parent 1: protocol ip prio 10 \
u32 match ip protocol 1 0xff flowid 1:2 \
action skbedit mark 17 \
action ife encode \
allow mark \
dst 02:15:15:15:15:15

Note: You dont need the skbedit action if you are already encoding the
skb mark earlier. A zero skb mark, when seen, will not be encoded.

Alternative hard code static mark of 0x12 every time the filter matches

sudo $TC filter add dev $ETH parent 1: protocol ip prio 10 \
u32 match ip protocol 1 0xff flowid 1:2 \
action ife encode \
type 0xDEAD \
use mark 0x12 \
dst 02:15:15:15:15:15
Signed-off-by: NJamal Hadi Salim <jhs@mojatatu.com>
Acked-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This action allows for a sending side to encapsulate arbitrary metadata
which is decapsulated by the receiving end.
The sender runs in encoding mode and the receiver in decode mode.
Both sender and receiver must specify the same ethertype.
At some point we hope to have a registered ethertype and we'll
then provide a default so the user doesnt have to specify it.
For now we enforce the user specify it.

Lets show example usage where we encode icmp from a sender towards
a receiver with an skbmark of 17; both sender and receiver use
ethertype of 0xdead to interop.

YYYY: Lets start with Receiver-side policy config:
xxx: add an ingress qdisc
sudo tc qdisc add dev $ETH ingress

xxx: any packets with ethertype 0xdead will be subjected to ife decoding
xxx: we then restart the classification so we can match on icmp at prio 3
sudo $TC filter add dev $ETH parent ffff: prio 2 protocol 0xdead \
u32 match u32 0 0 flowid 1:1 \
action ife decode reclassify

xxx: on restarting the classification from above if it was an icmp
xxx: packet, then match it here and continue to the next rule at prio 4
xxx: which will match based on skb mark of 17
sudo tc filter add dev $ETH parent ffff: prio 3 protocol ip \
u32 match ip protocol 1 0xff flowid 1:1 \
action continue

xxx: match on skbmark of 0x11 (decimal 17) and accept
sudo tc filter add dev $ETH parent ffff: prio 4 protocol ip \
handle 0x11 fw flowid 1:1 \
action ok

xxx: Lets show the decoding policy
sudo tc -s filter ls dev $ETH parent ffff: protocol 0xdead
xxx:
filter pref 2 u32
filter pref 2 u32 fh 800: ht divisor 1
filter pref 2 u32 fh 800::800 order 2048 key ht 800 bkt 0 flowid 1:1  (rule hit 0 success 0)
  match 00000000/00000000 at 0 (success 0 )
        action order 1: ife decode action reclassify
         index 1 ref 1 bind 1 installed 14 sec used 14 sec
         type: 0x0
         Metadata: allow mark allow hash allow prio allow qmap
        Action statistics:
        Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
        backlog 0b 0p requeues 0
xxx:
Observe that above lists all metadatum it can decode. Typically these
submodules will already be compiled into a monolithic kernel or
loaded as modules

YYYY: Lets show the sender side now ..

xxx: Add an egress qdisc on the sender netdev
sudo tc qdisc add dev $ETH root handle 1: prio
xxx:
xxx: Match all icmp packets to 192.168.122.237/24, then
xxx: tag the packet with skb mark of decimal 17, then
xxx: Encode it with:
xxx:	ethertype 0xdead
xxx:	add skb->mark to whitelist of metadatum to send
xxx:	rewrite target dst MAC address to 02:15:15:15:15:15
xxx:
sudo $TC filter add dev $ETH parent 1: protocol ip prio 10  u32 \
match ip dst 192.168.122.237/24 \
match ip protocol 1 0xff \
flowid 1:2 \
action skbedit mark 17 \
action ife encode \
type 0xDEAD \
allow mark \
dst 02:15:15:15:15:15

xxx: Lets show the encoding policy
sudo tc -s filter ls dev $ETH parent 1: protocol ip
xxx:
filter pref 10 u32
filter pref 10 u32 fh 800: ht divisor 1
filter pref 10 u32 fh 800::800 order 2048 key ht 800 bkt 0 flowid 1:2  (rule hit 0 success 0)
  match c0a87aed/ffffffff at 16 (success 0 )
  match 00010000/00ff0000 at 8 (success 0 )

	action order 1:  skbedit mark 17
	 index 6 ref 1 bind 1
 	Action statistics:
	Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
	backlog 0b 0p requeues 0

	action order 2: ife encode action pipe
	 index 3 ref 1 bind 1
	 dst MAC: 02:15:15:15:15:15 type: 0xDEAD
 	 Metadata: allow mark
 	Action statistics:
	Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
	backlog 0b 0p requeues 0
xxx:

test by sending ping from sender to destination
Signed-off-by: NJamal Hadi Salim <jhs@mojatatu.com>
Acked-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In the initial implementation the only way to stop a rule from being
inserted into the hardware table was via the device feature flag.
However this doesn't work well when working on an end host system
where packets are expect to hit both the hardware and software
datapaths.

For example we can imagine a rule that will match an IP address and
increment a field. If we install this rule in both hardware and
software we may increment the field twice. To date we have only
added support for the drop action so we have been able to ignore
these cases. But as we extend the action support we will hit this
example plus more such cases. Arguably these are not even corner
cases in many working systems these cases will be common.

To avoid forcing the driver to always abort (i.e. the above example)
this patch adds a flag to add a rule in software only. A careful
user can use this flag to build software and hardware datapaths
that work together. One example we have found particularly useful
is to use hardware resources to set the skb->mark on the skb when
the match may be expensive to run in software but a mark lookup
in a hash table is cheap. The idea here is hardware can do in one
lookup what the u32 classifier may need to traverse multiple lists
and hash tables to compute. The flag is only passed down on inserts.
On deletion to avoid stale references in hardware we always try
to remove a rule if it exists.

The flags field is part of the classifier specific options. Although
it is tempting to lift this into the generic structure doing this
proves difficult do to how the tc netlink attributes are implemented
along with how the dump/change routines are called. There is also
precedence for putting seemingly generic pieces in the specific
classifier options such as TCA_U32_POLICE, TCA_U32_ACT, etc. So
although not ideal I've left FLAGS in the u32 options as well as it
simplifies the code greatly and user space has already learned how
to manage these bits ala 'tc' tool.

Another thing if trying to update a rule we require the flags to
be unchanged. This is to force user space, software u32 and
the hardware u32 to keep in sync. Thanks to Simon Horman for
catching this case.
Signed-off-by: NJohn Fastabend <john.r.fastabend@intel.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The offload decision was originally very basic and tied to if the dev
implemented the appropriate ndo op hook. The next step is to allow
the user to more flexibly define if any paticular rule should be
offloaded or not. In order to have this logic in one function lift
the current check into a helper routine tc_should_offload().
Signed-off-by: NJohn Fastabend <john.r.fastabend@intel.com>
Acked-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Similarly, we need to update backlog too when we update qlen.

Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: NCong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>