Packet extraction failures over register-based MMIO are silent, and
difficult to pinpoint. Add an error message to remedy this.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Automated tools complain that felix_check_xtr_pkt() has logic to drain
the CPU queue on the reception of a PTP packet over Ethernet, yet it
returns an uninitialized error code in the case where the CPU queue was
empty.

This is not likely to happen (/possible if hardware works correctly),
but it isn't a fatal condition either. The PTP packet will be dequeued
from the CPU queue when the next PTP packet arrives. So initialize "err"
to 0 for the case where nothing was dequeued during this iteration.
Reported-by: kernel test robot <lkp@intel.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The DSA ->port_rxtstamp() function is never called for PTP_CLASS_NONE:

dsa_skb_defer_rx_timestamp:

	if (type == PTP_CLASS_NONE)
		return false;

	if (likely(ds->ops->port_rxtstamp))
		return ds->ops->port_rxtstamp(ds, p->dp->index, skb, type);

So practically, the argument is unused, so remove it.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This assignment is redundant, since ocelot->npi has already been set to
-1 by felix_npi_port_deinit(). Call path:

felix_change_tag_protocol
-> felix_del_tag_protocol(DSA_TAG_PROTO_OCELOT)
   -> felix_teardown_tag_npi
      -> felix_npi_port_deinit
-> felix_set_tag_protocol(DSA_TAG_PROTO_OCELOT_8021Q)
   -> felix_setup_tag_8021q
      -> felix_8021q_cpu_port_init
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Hardcoding these IP protocol numbers in is2_entry_set() obscures the
purpose of the code, so replace the magic numbers with the definitions
from linux/in.h.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Simplify ocelot_vcap_block_remove_filter by using list_for_each_entry
instead of list_for_each.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Stephen reported the following warning messages from smc-sysctl.rst

Documentation/networking/smc-sysctl.rst:3: WARNING: Title overline
too short.
Documentation/networking/smc-sysctl.rst: WARNING: document isn't
included in any toctree

Fix the title overline and add smc-sysctl entry into
Documentation/networking/index.rst

Fixes: 12bbb0d1 ("net/smc: add sysctl for autocorking")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Dust Li <dust.li@linux.alibaba.com>
Link: https://lore.kernel.org/r/20220303113527.62047-1-dust.li@linux.alibaba.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Fix following coccicheck warning:
drivers/net/ethernet/marvell/mv643xx_eth.c:1664:35-36: WARNING opportunity for min()
Signed-off-by: Haowen Bai <baihaowen88@gmail.com>
Link: https://lore.kernel.org/r/1646271529-7659-1-git-send-email-baihaowen88@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

net/batman-adv/hard-interface.c
  commit 690bb6fb ("batman-adv: Request iflink once in batadv-on-batadv check")
  commit 6ee3c393 ("batman-adv: Demote batadv-on-batadv skip error message")
https://lore.kernel.org/all/20220302163049.101957-1-sw@simonwunderlich.de/

net/smc/af_smc.c
  commit 4d08b7b5 ("net/smc: Fix cleanup when register ULP fails")
  commit 462791bb ("net/smc: add sysctl interface for SMC")
https://lore.kernel.org/all/20220302112209.355def40@canb.auug.org.au/Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Pull networking fixes from Jakub Kicinski:
 "Including fixes from can, xfrm, wifi, bluetooth, and netfilter.

  Lots of various size fixes, the length of the tag speaks for itself.
  Most of the 5.17-relevant stuff comes from xfrm, wifi and bt trees
  which had been lagging as you pointed out previously. But there's also
  a larger than we'd like portion of fixes for bugs from previous
  releases.

  Three more fixes still under discussion, including and xfrm revert for
  uAPI error.

  Current release - regressions:

   - iwlwifi: don't advertise TWT support, prevent FW crash

   - xfrm: fix the if_id check in changelink

   - xen/netfront: destroy queues before real_num_tx_queues is zeroed

   - bluetooth: fix not checking MGMT cmd pending queue, make scanning
     work again

  Current release - new code bugs:

   - mptcp: make SIOCOUTQ accurate for fallback socket

   - bluetooth: access skb->len after null check

   - bluetooth: hci_sync: fix not using conn_timeout

   - smc: fix cleanup when register ULP fails

   - dsa: restore error path of dsa_tree_change_tag_proto

   - iwlwifi: fix build error for IWLMEI

   - iwlwifi: mvm: propagate error from request_ownership to the user

  Previous releases - regressions:

   - xfrm: fix pMTU regression when reported pMTU is too small

   - xfrm: fix TCP MSS calculation when pMTU is close to 1280

   - bluetooth: fix bt_skb_sendmmsg not allocating partial chunks

   - ipv6: ensure we call ipv6_mc_down() at most once, prevent leaks

   - ipv6: prevent leaks in igmp6 when input queues get full

   - fix up skbs delta_truesize in UDP GRO frag_list

   - eth: e1000e: fix possible HW unit hang after an s0ix exit

   - eth: e1000e: correct NVM checksum verification flow

   - ptp: ocp: fix large time adjustments

  Previous releases - always broken:

   - tcp: make tcp_read_sock() more robust in presence of urgent data

   - xfrm: distinguishing SAs and SPs by if_id in xfrm_migrate

   - xfrm: fix xfrm_migrate issues when address family changes

   - dcb: flush lingering app table entries for unregistered devices

   - smc: fix unexpected SMC_CLC_DECL_ERR_REGRMB error

   - mac80211: fix EAPoL rekey fail in 802.3 rx path

   - mac80211: fix forwarded mesh frames AC & queue selection

   - netfilter: nf_queue: fix socket access races and bugs

   - batman-adv: fix ToCToU iflink problems and check the result belongs
     to the expected net namespace

   - can: gs_usb, etas_es58x: fix opened_channel_cnt's accounting

   - can: rcar_canfd: register the CAN device when fully ready

   - eth: igb, igc: phy: drop premature return leaking HW semaphore

   - eth: ixgbe: xsk: change !netif_carrier_ok() handling in
     ixgbe_xmit_zc(), prevent live lock when link goes down

   - eth: stmmac: only enable DMA interrupts when ready

   - eth: sparx5: move vlan checks before any changes are made

   - eth: iavf: fix races around init, removal, resets and vlan ops

   - ibmvnic: more reset flow fixes

  Misc:

   - eth: fix return value of __setup handlers"

* tag 'net-5.17-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (92 commits)
  ipv6: fix skb drops in igmp6_event_query() and igmp6_event_report()
  net: dsa: make dsa_tree_change_tag_proto actually unwind the tag proto change
  ixgbe: xsk: change !netif_carrier_ok() handling in ixgbe_xmit_zc()
  selftests: mlxsw: resource_scale: Fix return value
  selftests: mlxsw: tc_police_scale: Make test more robust
  net: dcb: disable softirqs in dcbnl_flush_dev()
  bnx2: Fix an error message
  sfc: extend the locking on mcdi->seqno
  net/smc: fix unexpected SMC_CLC_DECL_ERR_REGRMB error cause by server
  net/smc: fix unexpected SMC_CLC_DECL_ERR_REGRMB error generated by client
  net: arcnet: com20020: Fix null-ptr-deref in com20020pci_probe()
  tcp: make tcp_read_sock() more robust
  bpf, sockmap: Do not ignore orig_len parameter
  net: ipa: add an interconnect dependency
  net: fix up skbs delta_truesize in UDP GRO frag_list
  iwlwifi: mvm: return value for request_ownership
  nl80211: Update bss channel on channel switch for P2P_CLIENT
  iwlwifi: fix build error for IWLMEI
  ptp: ocp: Add ptp_ocp_adjtime_coarse for large adjustments
  batman-adv: Don't expect inter-netns unique iflink indices
  ...

Pull MIPS fixes from Thomas Bogendoerfer:

 - Fix memory detection for MT7621 devices

 - Fix setnocoherentio kernel option

 - Fix warning when CONFIG_SCHED_CORE is enabled

* tag 'mips-fixes-5.17_4' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
  MIPS: ralink: mt7621: use bitwise NOT instead of logical
  mips: setup: fix setnocoherentio() boolean setting
  MIPS: smp: fill in sibling and core maps earlier
  MIPS: ralink: mt7621: do memory detection on KSEG1

Pull auxdisplay fixes from Miguel Ojeda:
 "A few lcd2s fixes from Andy Shevchenko"

* tag 'auxdisplay-for-linus-v5.17-rc7' of git://github.com/ojeda/linux:
  auxdisplay: lcd2s: Use proper API to free the instance of charlcd object
  auxdisplay: lcd2s: Fix memory leak in ->remove()
  auxdisplay: lcd2s: Fix lcd2s_redefine_char() feature

While investigating on why a synchronize_net() has been added recently
in ipv6_mc_down(), I found that igmp6_event_query() and igmp6_event_report()
might drop skbs in some cases.

Discussion about removing synchronize_net() from ipv6_mc_down()
will happen in a different thread.

Fixes: f185de28 ("mld: add new workqueues for process mld events")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Taehee Yoo <ap420073@gmail.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20220303173728.937869-1-eric.dumazet@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

The blamed commit said one thing but did another. It explains that we
should restore the "return err" to the original "goto out_unwind_tagger",
but instead it replaced it with "goto out_unlock".

When DSA_NOTIFIER_TAG_PROTO fails after the first switch of a
multi-switch tree, the switches would end up not using the same tagging
protocol.

Fixes: 0b0e2ff1 ("net: dsa: restore error path of dsa_tree_change_tag_proto")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20220303154249.1854436-1-vladimir.oltean@nxp.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Commit c685c69f ("ixgbe: don't do any AF_XDP zero-copy transmit if
netif is not OK") addressed the ring transient state when
MEM_TYPE_XSK_BUFF_POOL was being configured which in turn caused the
interface to through down/up. Maurice reported that when carrier is not
ok and xsk_pool is present on ring pair, ksoftirqd will consume 100% CPU
cycles due to the constant NAPI rescheduling as ixgbe_poll() states that
there is still some work to be done.

To fix this, do not set work_done to false for a !netif_carrier_ok().

Fixes: c685c69f ("ixgbe: don't do any AF_XDP zero-copy transmit if netif is not OK")
Reported-by: Maurice Baijens <maurice.baijens@ellips.com>
Tested-by: Maurice Baijens <maurice.baijens@ellips.com>
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
Tested-by: Sandeep Penigalapati <sandeep.penigalapati@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Ido Schimmel says:

====================
selftests: mlxsw: A couple of fixes

Patch #1 fixes a breakage due to a change in iproute2 output. The real
problem is not iproute2, but the fact that the check was not strict
enough. Fixed by using JSON output instead. Targeting at net so that the
test will pass as part of old and new kernels regardless of iproute2
version.

Patch #2 fixes an issue uncovered by the first one.
====================

Link: https://lore.kernel.org/r/20220302161447.217447-1-idosch@nvidia.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

The test runs several test cases and is supposed to return an error in
case at least one of them failed.

Currently, the check of the return value of each test case is in the
wrong place, which can result in the wrong return value. For example:

 # TESTS='tc_police' ./resource_scale.sh
 TEST: 'tc_police' [default] 968                                     [FAIL]
         tc police offload count failed
 Error: mlxsw_spectrum: Failed to allocate policer index.
 We have an error talking to the kernel
 Command failed /tmp/tmp.i7Oc5HwmXY:969
 TEST: 'tc_police' [default] overflow 969                            [ OK ]
 ...
 TEST: 'tc_police' [ipv4_max] overflow 969                           [ OK ]

 $ echo $?
 0

Fix this by moving the check to be done after each test case.

Fixes: 059b18e2 ("selftests: mlxsw: Return correct error code in resource scale test")
Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

The test adds tc filters and checks how many of them were offloaded by
grepping for 'in_hw'.

iproute2 commit f4cd4f127047 ("tc: add skip_hw and skip_sw to control
action offload") added offload indication to tc actions, producing the
following output:

 $ tc filter show dev swp2 ingress
 ...
 filter protocol ipv6 pref 1000 flower chain 0 handle 0x7c0
   eth_type ipv6
   dst_ip 2001:db8:1::7bf
   skip_sw
   in_hw in_hw_count 1
         action order 1:  police 0x7c0 rate 10Mbit burst 100Kb mtu 2Kb action drop overhead 0b
         ref 1 bind 1
         not_in_hw
         used_hw_stats immediate

The current grep expression matches on both 'in_hw' and 'not_in_hw',
resulting in incorrect results.

Fix that by using JSON output instead.

Fixes: 5061e773 ("selftests: mlxsw: Add scale test for tc-police")
Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

Ido Schimmel points out that since commit 52cff74e ("dcbnl : Disable
software interrupts before taking dcb_lock"), the DCB API can be called
by drivers from softirq context.

One such in-tree example is the chelsio cxgb4 driver:
dcb_rpl
-> cxgb4_dcb_handle_fw_update
   -> dcb_ieee_setapp

If the firmware for this driver happened to send an event which resulted
in a call to dcb_ieee_setapp() at the exact same time as another
DCB-enabled interface was unregistering on the same CPU, the softirq
would deadlock, because the interrupted process was already holding the
dcb_lock in dcbnl_flush_dev().

Fix this unlikely event by using spin_lock_bh() in dcbnl_flush_dev() as
in the rest of the dcbnl code.

Fixes: 91b0383f ("net: dcb: flush lingering app table entries for unregistered devices")
Reported-by: Ido Schimmel <idosch@idosch.org>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20220302193939.1368823-1-vladimir.oltean@nxp.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Fix an error message and report the correct failing function.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

Jonathan Lemon says:

====================
ptp: ocp: TOD and monitoring updates

Add a series of patches for monitoring the status of the
driver and adjusting TOD handling, especially around leap seconds.

Add documentation for the new sysfs nodes.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Add documentation for the tod_correction, clock_status_drift,
and clock_status_offset nodes.
Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

utc_tai_offset is used to correct IRIG, DCF and NMEA outputs and is
set during initialisation but is not corrected during leap second
announce event.  Add watchdog code to control this correction.
Signed-off-by: Vadim Fedorenko <vadfed@fb.com>
Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

TOD correction register is used to compensate for leap seconds in
different domains.  Export it as an attribute with write access.
Signed-off-by: Vadim Fedorenko <vadfed@fb.com>
Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Monitoring of clock variance could be done through checking
the offset and the drift updates that are applied to atomic
clocks.  Expose these values as attributes for the timecard.
Signed-off-by: Vadim Fedorenko <vadfed@fb.com>
Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

TOD information is currently displayed only on module load,
which doesn't provide updated information as the system runs.

Create a debug file which provides the current TOD status information,
and move the information display there.
Signed-off-by: Vadim Fedorenko <vadfed@fb.com>
Signed-off-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Martin KaFai Lau says:

====================
Preserve mono delivery time (EDT) in skb->tstamp

skb->tstamp was first used as the (rcv) timestamp.
The major usage is to report it to the user (e.g. SO_TIMESTAMP).

Later, skb->tstamp is also set as the (future) delivery_time (e.g. EDT in TCP)
during egress and used by the qdisc (e.g. sch_fq) to make decision on when
the skb can be passed to the dev.

Currently, there is no way to tell skb->tstamp having the (rcv) timestamp
or the delivery_time, so it is always reset to 0 whenever forwarded
between egress and ingress.

While it makes sense to always clear the (rcv) timestamp in skb->tstamp
to avoid confusing sch_fq that expects the delivery_time, it is a
performance issue [0] to clear the delivery_time if the skb finally
egress to a fq@phy-dev.

This set is to keep the mono delivery time and make it available to
the final egress interface.  Please see individual patch for
the details.

[0] (slide 22): https://linuxplumbersconf.org/event/11/contributions/953/attachments/867/1658/LPC_2021_BPF_Datapath_Extensions.pdf

v6:
- Add kdoc and use non-UAPI type in patch 6 (Jakub)

v5:
netdev:
- Patch 3 in v4 is broken down into smaller patches 3, 4, and 5 in v5
- The mono_delivery_time bit clearing in __skb_tstamp_tx() is
  done in __net_timestamp() instead.  This is patch 4 in v5.
- Missed a skb_clear_delivery_time() for the 'skip_classify' case
  in dev.c in v4.  That is fixed in patch 5 in v5 for correctness.
  The skb_clear_delivery_time() will be moved to a later
  stage in Patch 10, so it was an intermediate error in v4.
- Added delivery time handling for nfnetlink_{log, queue}.c in patch 9 (Daniel)
- Added delivery time handling in the IPv6 IOAM hop-by-hop option which has
  an experimental IANA assigned value 49 in patch 8
- Added delivery time handling in nf_conntrack for the ipv6 defrag case
  in patch 7
- Removed unlikely() from testing skb->mono_delivery_time (Daniel)

bpf:
- Remove the skb->tstamp dance in ingress.  Depends on bpf insn
  rewrite to return 0 if skb->tstamp has delivery time in patch 11.
  It is to backward compatible with the existing tc-bpf@ingress in
  patch 11.
- bpf_set_delivery_time() will also allow dtime == 0 and
  dtime_type == BPF_SKB_DELIVERY_TIME_NONE as argument
  in patch 12.

v4:
netdev:
- Push the skb_clear_delivery_time() from
  ip_local_deliver() and ip6_input() to
  ip_local_deliver_finish() and ip6_input_finish()
  to accommodate the ipvs forward path.
  This is the notable change in v4 at the netdev side.

    - Patch 3/8 first does the skb_clear_delivery_time() after
      sch_handle_ingress() in dev.c and this will make the
      tc-bpf forward path work via the bpf_redirect_*() helper.

    - The next patch 4/8 (new in v4) will then postpone the
      skb_clear_delivery_time() from dev.c to
      the ip_local_deliver_finish() and ip6_input_finish() after
      taking care of the tstamp usage in the ip defrag case.
      This will make the kernel forward path also work, e.g.
      the ip[6]_forward().

- Fixed a case v3 which missed setting the skb->mono_delivery_time bit
  when sending TCP rst/ack in some cases (e.g. from a ctl_sk).
  That case happens at ip_send_unicast_reply() and
  tcp_v6_send_response().  It is fixed in patch 1/8 (and
  then patch 3/8) in v4.

bpf:
- Adding __sk_buff->delivery_time_type instead of adding
  __sk_buff->mono_delivery_time as in v3.  The tc-bpf can stay with
  one __sk_buff->tstamp instead of having two 'time' fields
  while one is 0 and another is not.
  tc-bpf can use the new __sk_buff->delivery_time_type to tell
  what is stored in __sk_buff->tstamp.
- bpf_skb_set_delivery_time() helper is added to set
  __sk_buff->tstamp from non mono delivery_time to
  mono delivery_time
- Most of the convert_ctx_access() bpf insn rewrite in v3
  is gone, so no new rewrite added for __sk_buff->tstamp.
  The only rewrite added is for reading the new
  __sk_buff->delivery_time_type.
- Added selftests, test_tc_dtime.c

v3:
- Feedback from v2 is using shinfo(skb)->tx_flags could be racy.
- Considered to reuse a few bits in skb->tstamp to represent
  different semantics, other than more code churns, it will break
  the bpf usecase which currently can write and then read back
  the skb->tstamp.
- Went back to v1 idea on adding a bit to skb and address the
  feedbacks on v1:
- Added one bit skb->mono_delivery_time to flag that
  the skb->tstamp has the mono delivery_time (EDT), instead
  of adding a bit to flag if the skb->tstamp has been forwarded or not.
- Instead of resetting the delivery_time back to the (rcv) timestamp
  during recvmsg syscall which may be too late and not useful,
  the delivery_time reset in v3 happens earlier once the stack
  knows that the skb will be delivered locally.
- Handled the tapping@ingress case by af_packet
- No need to change the (rcv) timestamp to mono clock base as in v1.
  The added one bit to flag skb->mono_delivery_time is enough
  to keep the EDT delivery_time during forward.
- Added logic to the bpf side to make the existing bpf
  running at ingress can still get the (rcv) timestamp
  when reading the __sk_buff->tstamp.  New __sk_buff->mono_delivery_time
  is also added.  Test is still needed to test this piece.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

This patch adds tests on forwarding the delivery_time for
the following cases
- tcp/udp + ip4/ip6 + bpf_redirect_neigh
- tcp/udp + ip4/ip6 + ip[6]_forward
- bpf_skb_set_delivery_time
- The old rcv timestamp expectation on tc-bpf@ingress
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

* __sk_buff->delivery_time_type:
This patch adds __sk_buff->delivery_time_type.  It tells if the
delivery_time is stored in __sk_buff->tstamp or not.

It will be most useful for ingress to tell if the __sk_buff->tstamp
has the (rcv) timestamp or delivery_time.  If delivery_time_type
is 0 (BPF_SKB_DELIVERY_TIME_NONE), it has the (rcv) timestamp.

Two non-zero types are defined for the delivery_time_type,
BPF_SKB_DELIVERY_TIME_MONO and BPF_SKB_DELIVERY_TIME_UNSPEC.  For UNSPEC,
it can only happen in egress because only mono delivery_time can be
forwarded to ingress now.  The clock of UNSPEC delivery_time
can be deduced from the skb->sk->sk_clockid which is how
the sch_etf doing it also.

* Provide forwarded delivery_time to tc-bpf@ingress:
With the help of the new delivery_time_type, the tc-bpf has a way
to tell if the __sk_buff->tstamp has the (rcv) timestamp or
the delivery_time.  During bpf load time, the verifier will learn if
the bpf prog has accessed the new __sk_buff->delivery_time_type.
If it does, it means the tc-bpf@ingress is expecting the
skb->tstamp could have the delivery_time.  The kernel will then
read the skb->tstamp as-is during bpf insn rewrite without
checking the skb->mono_delivery_time.  This is done by adding a
new prog->delivery_time_access bit.  The same goes for
writing skb->tstamp.

* bpf_skb_set_delivery_time():
The bpf_skb_set_delivery_time() helper is added to allow setting both
delivery_time and the delivery_time_type at the same time.  If the
tc-bpf does not need to change the delivery_time_type, it can directly
write to the __sk_buff->tstamp as the existing tc-bpf has already been
doing.  It will be most useful at ingress to change the
__sk_buff->tstamp from the (rcv) timestamp to
a mono delivery_time and then bpf_redirect_*().

bpf only has mono clock helper (bpf_ktime_get_ns), and
the current known use case is the mono EDT for fq, and
only mono delivery time can be kept during forward now,
so bpf_skb_set_delivery_time() only supports setting
BPF_SKB_DELIVERY_TIME_MONO.  It can be extended later when use cases
come up and the forwarding path also supports other clock bases.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The current tc-bpf@ingress reads and writes the __sk_buff->tstamp
as a (rcv) timestamp which currently could either be 0 (not available)
or ktime_get_real().  This patch is to backward compatible with the
(rcv) timestamp expectation at ingress.  If the skb->tstamp has
the delivery_time, the bpf insn rewrite will read 0 for tc-bpf
running at ingress as it is not available.  When writing at ingress,
it will also clear the skb->mono_delivery_time bit.

/* BPF_READ: a = __sk_buff->tstamp */
if (!skb->tc_at_ingress || !skb->mono_delivery_time)
	a = skb->tstamp;
else
	a = 0

/* BPF_WRITE: __sk_buff->tstamp = a */
if (skb->tc_at_ingress)
	skb->mono_delivery_time = 0;
skb->tstamp = a;

[ A note on the BPF_CGROUP_INET_INGRESS which can also access
  skb->tstamp.  At that point, the skb is delivered locally
  and skb_clear_delivery_time() has already been done,
  so the skb->tstamp will only have the (rcv) timestamp. ]

If the tc-bpf@egress writes 0 to skb->tstamp, the skb->mono_delivery_time
has to be cleared also.  It could be done together during
convert_ctx_access().  However, the latter patch will also expose
the skb->mono_delivery_time bit as __sk_buff->delivery_time_type.
Changing the delivery_time_type in the background may surprise
the user, e.g. the 2nd read on __sk_buff->delivery_time_type
may need a READ_ONCE() to avoid compiler optimization.  Thus,
in expecting the needs in the latter patch, this patch does a
check on !skb->tstamp after running the tc-bpf and clears the
skb->mono_delivery_time bit if needed.  The earlier discussion
on v4 [0].

The bpf insn rewrite requires the skb's mono_delivery_time bit and
tc_at_ingress bit.  They are moved up in sk_buff so that bpf rewrite
can be done at a fixed offset.  tc_skip_classify is moved together with
tc_at_ingress.  To get one bit for mono_delivery_time, csum_not_inet is
moved down and this bit is currently used by sctp.

[0]: https://lore.kernel.org/bpf/20220217015043.khqwqklx45c4m4se@kafai-mbp.dhcp.thefacebook.com/Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The previous patches handled the delivery_time in the ingress path
before the routing decision is made.  This patch can postpone clearing
delivery_time in a skb until knowing it is delivered locally and also
set the (rcv) timestamp if needed.  This patch moves the
skb_clear_delivery_time() from dev.c to ip_local_deliver_finish()
and ip6_input_finish().
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

If skb has the (rcv) timestamp available, nfnetlink_{log, queue}.c
logs/outputs it to the userspace.  When the locally generated skb is
looping from egress to ingress over a virtual interface (e.g. veth,
loopback...),  skb->tstamp may have the delivery time before it is
known that will be delivered locally and received by another sk.  Like
handling the delivery time in network tapping,  use ktime_get_real() to
get the (rcv) timestamp.  The earlier added helper skb_tstamp_cond() is
used to do this.  false is passed to the second 'cond' arg such
that doing ktime_get_real() or not only depends on the
netstamp_needed_key static key.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

IOAM is a hop-by-hop option with a temporary iana allocation (49).
Since it is hop-by-hop, it is done before the input routing decision.
One of the traced data field is the (rcv) timestamp.

When the locally generated skb is looping from egress to ingress over
a virtual interface (e.g. veth, loopback...), skb->tstamp may have the
delivery time before it is known that it will be delivered locally
and received by another sk.

Like handling the network tapping (tcpdump) in the earlier patch,
this patch gets the timestamp if needed without over-writing the
delivery_time in the skb->tstamp.  skb_tstamp_cond() is added to do the
ktime_get_real() with an extra cond arg to check on top of the
netstamp_needed_key static key.  skb_tstamp_cond() will also be used in
a latter patch and it needs the netstamp_needed_key check.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

A latter patch will postpone the delivery_time clearing until the stack
knows the skb is being delivered locally (i.e. calling
skb_clear_delivery_time() at ip_local_deliver_finish() for IPv4
and at ip6_input_finish() for IPv6).  That will allow other kernel
forwarding path (e.g. ip[6]_forward) to keep the delivery_time also.

A very similar IPv6 defrag codes have been duplicated in
multiple places: regular IPv6, nf_conntrack, and 6lowpan.

Unlike the IPv4 defrag which is done before ip_local_deliver_finish(),
the regular IPv6 defrag is done after ip6_input_finish().
Thus, no change should be needed in the regular IPv6 defrag
logic because skb_clear_delivery_time() should have been called.

6lowpan also does not need special handling on delivery_time
because it is a non-inet packet_type.

However, cf_conntrack has a case in NF_INET_PRE_ROUTING that needs
to do the IPv6 defrag earlier.  Thus, it needs to save the
mono_delivery_time bit in the inet_frag_queue which is similar
to how it is handled in the previous patch for the IPv4 defrag.

This patch chooses to do it consistently and stores the mono_delivery_time
in the inet_frag_queue for all cases such that it will be easier
for the future refactoring effort on the IPv6 reasm code.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

A latter patch will postpone the delivery_time clearing until the stack
knows the skb is being delivered locally.  That will allow other kernel
forwarding path (e.g. ip[6]_forward) to keep the delivery_time also.

An earlier attempt was to do skb_clear_delivery_time() in
ip_local_deliver() and ip6_input().  The discussion [0] requested
to move it one step later into ip_local_deliver_finish()
and ip6_input_finish() so that the delivery_time can be kept
for the ip_vs forwarding path also.

To do that, this patch also needs to take care of the (rcv) timestamp
usecase in ip_is_fragment().  It needs to expect delivery_time in
the skb->tstamp, so it needs to save the mono_delivery_time bit in
inet_frag_queue such that the delivery_time (if any) can be restored
in the final defragmented skb.

[Note that it will only happen when the locally generated skb is looping
 from egress to ingress over a virtual interface (e.g. veth, loopback...),
 skb->tstamp may have the delivery time before it is known that it will
 be delivered locally and received by another sk.]

[0]: https://lore.kernel.org/netdev/ca728d81-80e8-3767-d5e-d44f6ad96e43@ssi.bg/Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

The previous patches handled the delivery_time before sch_handle_ingress().

This patch can now set the skb->mono_delivery_time to flag the skb->tstamp
is used as the mono delivery_time (EDT) instead of the (rcv) timestamp
and also clear it with skb_clear_delivery_time() after
sch_handle_ingress().  This will make the bpf_redirect_*()
to keep the mono delivery_time and used by a qdisc (fq) of
the egress-ing interface.

A latter patch will postpone the skb_clear_delivery_time() until the
stack learns that the skb is being delivered locally and that will
make other kernel forwarding paths (ip[6]_forward) able to keep
the delivery_time also.  Thus, like the previous patches on using
the skb->mono_delivery_time bit, calling skb_clear_delivery_time()
is not limited within the CONFIG_NET_INGRESS to avoid too many code
churns among this set.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

In __skb_tstamp_tx(), it may clone the egress skb and queues the clone to
the sk_error_queue.  The outgoing skb may have the mono delivery_time
while the (rcv) timestamp is expected for the clone, so the
skb->mono_delivery_time bit needs to be cleared from the clone.

This patch adds the skb->mono_delivery_time clearing to the existing
__net_timestamp() and use it in __skb_tstamp_tx().
The __net_timestamp() fast path usage in dev.c is changed to directly
call ktime_get_real() since the mono_delivery_time bit is not set at
that point.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

A latter patch will set the skb->mono_delivery_time to flag the skb->tstamp
is used as the mono delivery_time (EDT) instead of the (rcv) timestamp.
skb_clear_tstamp() will then keep this delivery_time during forwarding.

This patch is to make the network tapping (with af_packet) to handle
the delivery_time stored in skb->tstamp.

Regardless of tapping at the ingress or egress,  the tapped skb is
received by the af_packet socket, so it is ingress to the af_packet
socket and it expects the (rcv) timestamp.

When tapping at egress, dev_queue_xmit_nit() is used.  It has already
expected skb->tstamp may have delivery_time,  so it does
skb_clone()+net_timestamp_set() to ensure the cloned skb has
the (rcv) timestamp before passing to the af_packet sk.
This patch only adds to clear the skb->mono_delivery_time
bit in net_timestamp_set().

When tapping at ingress, it currently expects the skb->tstamp is either 0
or the (rcv) timestamp.  Meaning, the tapping at ingress path
has already expected the skb->tstamp could be 0 and it will get
the (rcv) timestamp by ktime_get_real() when needed.

There are two cases for tapping at ingress:

One case is af_packet queues the skb to its sk_receive_queue.
The skb is either not shared or new clone created.  The newly
added skb_clear_delivery_time() is called to clear the
delivery_time (if any) and set the (rcv) timestamp if
needed before the skb is queued to the sk_receive_queue.

Another case, the ingress skb is directly copied to the rx_ring
and tpacket_get_timestamp() is used to get the (rcv) timestamp.
The newly added skb_tstamp() is used in tpacket_get_timestamp()
to check the skb->mono_delivery_time bit before returning skb->tstamp.
As mentioned earlier, the tapping@ingress has already expected
the skb may not have the (rcv) timestamp (because no sk has asked
for it) and has handled this case by directly calling ktime_get_real().
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Right now, skb->tstamp is reset to 0 whenever the skb is forwarded.

If skb->tstamp has the mono delivery_time, clearing it can hurt
the performance when it finally transmits out to fq@phy-dev.

The earlier patch added a skb->mono_delivery_time bit to
flag the skb->tstamp carrying the mono delivery_time.

This patch adds skb_clear_tstamp() helper which keeps
the mono delivery_time and clears everything else.

The delivery_time clearing will be postponed until the stack knows the
skb will be delivered locally.  It will be done in a latter patch.
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

skb->tstamp was first used as the (rcv) timestamp.
The major usage is to report it to the user (e.g. SO_TIMESTAMP).

Later, skb->tstamp is also set as the (future) delivery_time (e.g. EDT in TCP)
during egress and used by the qdisc (e.g. sch_fq) to make decision on when
the skb can be passed to the dev.

Currently, there is no way to tell skb->tstamp having the (rcv) timestamp
or the delivery_time, so it is always reset to 0 whenever forwarded
between egress and ingress.

While it makes sense to always clear the (rcv) timestamp in skb->tstamp
to avoid confusing sch_fq that expects the delivery_time, it is a
performance issue [0] to clear the delivery_time if the skb finally
egress to a fq@phy-dev.  For example, when forwarding from egress to
ingress and then finally back to egress:

            tcp-sender => veth@netns => veth@hostns => fq@eth0@hostns
                                     ^              ^
                                     reset          rest

This patch adds one bit skb->mono_delivery_time to flag the skb->tstamp
is storing the mono delivery_time (EDT) instead of the (rcv) timestamp.

The current use case is to keep the TCP mono delivery_time (EDT) and
to be used with sch_fq.  A latter patch will also allow tc-bpf@ingress
to read and change the mono delivery_time.

In the future, another bit (e.g. skb->user_delivery_time) can be added
for the SCM_TXTIME where the clock base is tracked by sk->sk_clockid.

[ This patch is a prep work.  The following patches will
  get the other parts of the stack ready first.  Then another patch
  after that will finally set the skb->mono_delivery_time. ]

skb_set_delivery_time() function is added.  It is used by the tcp_output.c
and during ip[6] fragmentation to assign the delivery_time to
the skb->tstamp and also set the skb->mono_delivery_time.

A note on the change in ip_send_unicast_reply() in ip_output.c.
It is only used by TCP to send reset/ack out of a ctl_sk.
Like the new skb_set_delivery_time(), this patch sets
the skb->mono_delivery_time to 0 for now as a place
holder.  It will be enabled in a latter patch.
A similar case in tcp_ipv6 can be done with
skb_set_delivery_time() in tcp_v6_send_response().

[0] (slide 22): https://linuxplumbersconf.org/event/11/contributions/953/attachments/867/1658/LPC_2021_BPF_Datapath_Extensions.pdfSigned-off-by: Martin KaFai Lau <kafai@fb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>