net-timestamp: COMPLETION timestamp on packet tx completion

Add SOF_TIMESTAMPING_TX_COMPLETION, for requesting a software timestamp
when hardware reports a packet completed.

Completion tstamp is us

net-timestamp: COMPLETION timestamp on packet tx completion

Add SOF_TIMESTAMPING_TX_COMPLETION, for requesting a software timestamp
when hardware reports a packet completed.

Completion tstamp is useful for Bluetooth, as hardware timestamps do not
exist in the HCI specification except for ISO packets, and the hardware
has a queue where packets may wait. In this case the software SND
timestamp only reflects the kernel-side part of the total latency
(usually small) and queue length (usually 0 unless HW buffers
congested), whereas the completion report time is more informative of
the true latency.

It may also be useful in other cases where HW TX timestamps cannot be
obtained and user wants to estimate an upper bound to when the TX
probably happened.

Signed-off-by: Pauli Virtanen <[email protected]>
Reviewed-by: Willem de Bruijn <[email protected]>
Signed-off-by: Luiz Augusto von Dentz <[email protected]>

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net: Add the possibility to support a selected hwtstamp in netdevice

Introduce the description of a hwtstamp provider, mainly defined with a
the hwtstamp source and the phydev pointer.

Add a hwtsta

net: Add the possibility to support a selected hwtstamp in netdevice

Introduce the description of a hwtstamp provider, mainly defined with a
the hwtstamp source and the phydev pointer.

Add a hwtstamp provider description within the netdev structure to
allow saving the hwtstamp we want to use. This prepares for future
support of an ethtool netlink command to select the desired hwtstamp
provider. By default, the old API that does not support hwtstamp
selectability is used, meaning the hwtstamp provider pointer is unset.

Signed-off-by: Kory Maincent <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net-timestamp: introduce SOF_TIMESTAMPING_OPT_RX_FILTER flag

introduce a new flag SOF_TIMESTAMPING_OPT_RX_FILTER in the receive
path. User can set it with SOF_TIMESTAMPING_SOFTWARE to filter
out rx

net-timestamp: introduce SOF_TIMESTAMPING_OPT_RX_FILTER flag

introduce a new flag SOF_TIMESTAMPING_OPT_RX_FILTER in the receive
path. User can set it with SOF_TIMESTAMPING_SOFTWARE to filter
out rx software timestamp report, especially after a process turns on
netstamp_needed_key which can time stamp every incoming skb.

Previously, we found out if an application starts first which turns on
netstamp_needed_key, then another one only passing SOF_TIMESTAMPING_SOFTWARE
could also get rx timestamp. Now we handle this case by introducing this
new flag without breaking users.

Quoting Willem to explain why we need the flag:
"why a process would want to request software timestamp reporting, but
not receive software timestamp generation. The only use I see is when
the application does request
SOF_TIMESTAMPING_SOFTWARE | SOF_TIMESTAMPING_TX_SOFTWARE."

Similarly, this new flag could also be used for hardware case where we
can set it with SOF_TIMESTAMPING_RAW_HARDWARE, then we won't receive
hardware receive timestamp.

Another thing about errqueue in this patch I have a few words to say:
In this case, we need to handle the egress path carefully, or else
reporting the tx timestamp will fail. Egress path and ingress path will
finally call sock_recv_timestamp(). We have to distinguish them.
Errqueue is a good indicator to reflect the flow direction.

Suggested-by: Willem de Bruijn <[email protected]>
Signed-off-by: Jason Xing <[email protected]>
Reviewed-by: Willem de Bruijn <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

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net: partial revert of the "Make timestamping selectable: series

Revert following commits:

commit acec05fb78ab ("net_tstamp: Add TIMESTAMPING SOFTWARE and HARDWARE mask")
commit 11d55be06df0 ("net:

net: partial revert of the "Make timestamping selectable: series

Revert following commits:

commit acec05fb78ab ("net_tstamp: Add TIMESTAMPING SOFTWARE and HARDWARE mask")
commit 11d55be06df0 ("net: ethtool: Add a command to expose current time stamping layer")
commit bb8645b00ced ("netlink: specs: Introduce new netlink command to get current timestamp")
commit d905f9c75329 ("net: ethtool: Add a command to list available time stamping layers")
commit aed5004ee7a0 ("netlink: specs: Introduce new netlink command to list available time stamping layers")
commit 51bdf3165f01 ("net: Replace hwtstamp_source by timestamping layer")
commit 0f7f463d4821 ("net: Change the API of PHY default timestamp to MAC")
commit 091fab122869 ("net: ethtool: ts: Update GET_TS to reply the current selected timestamp")
commit 152c75e1d002 ("net: ethtool: ts: Let the active time stamping layer be selectable")
commit ee60ea6be0d3 ("netlink: specs: Introduce time stamping set command")

They need more time for reviews.

Link: https://lore.kernel.org/all/[email protected]/
Signed-off-by: Jakub Kicinski <[email protected]>

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net: ethtool: Add a command to expose current time stamping layer

Time stamping on network packets may happen either in the MAC or in
the PHY, but not both. In preparation for making the choice
sel

net: ethtool: Add a command to expose current time stamping layer

Time stamping on network packets may happen either in the MAC or in
the PHY, but not both. In preparation for making the choice
selectable, expose both the current layers via ethtool.

In accordance with the kernel implementation as it stands, the current
layer will always read as "phy" when a PHY time stamping device is
present. Future patches will allow changing the current layer
administratively.

Signed-off-by: Kory Maincent <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net_tstamp: Add TIMESTAMPING SOFTWARE and HARDWARE mask

Timestamping software or hardware flags are often used as a group,
therefore adding these masks will easier future use.

I did not use SOF_TIM

net_tstamp: Add TIMESTAMPING SOFTWARE and HARDWARE mask

Timestamping software or hardware flags are often used as a group,
therefore adding these masks will easier future use.

I did not use SOF_TIMESTAMPING_SYS_HARDWARE flag as it is deprecated and
not use at all.

Signed-off-by: Kory Maincent <[email protected]>
Reviewed-by: Willem de Bruijn <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net_tstamp: add SOF_TIMESTAMPING_OPT_ID_TCP

Add an option to initialize SOF_TIMESTAMPING_OPT_ID for TCP from
write_seq sockets instead of snd_una.

This should have been the behavior from the start.

net_tstamp: add SOF_TIMESTAMPING_OPT_ID_TCP

Add an option to initialize SOF_TIMESTAMPING_OPT_ID for TCP from
write_seq sockets instead of snd_una.

This should have been the behavior from the start. Because processes
may now exist that rely on the established behavior, do not change
behavior of the existing option, but add the right behavior with a new
flag. It is encouraged to always set SOF_TIMESTAMPING_OPT_ID_TCP on
stream sockets along with the existing SOF_TIMESTAMPING_OPT_ID.

Intuitively the contract is that the counter is zero after the
setsockopt, so that the next write N results in a notification for
the last byte N - 1.

On idle sockets snd_una == write_seq and this holds for both. But on
sockets with data in transmission, snd_una records the unacked offset
in the stream. This depends on the ACK response from the peer. A
process cannot learn this in a race free manner (ioctl SIOCOUTQ is one
racy approach).

write_seq records the offset at the last byte written by the process.
This is a better starting point. It matches the intuitive contract in
all circumstances, unaffected by external behavior.

The new timestamp flag necessitates increasing sk_tsflags to 32 bits.
Move the field in struct sock to avoid growing the socket (for some
common CONFIG variants). The UAPI interface so_timestamping.flags is
already int, so 32 bits wide.

Reported-by: Sotirios Delimanolis <[email protected]>
Signed-off-by: Willem de Bruijn <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

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net_tstamp: define new flag HWTSTAMP_FLAG_BONDED_PHC_INDEX

As we defined the new hwtstamp_config flag HWTSTAMP_FLAG_BONDED_PHC_INDEX
as enum, it's not easy for userspace program to check if the flag

net_tstamp: define new flag HWTSTAMP_FLAG_BONDED_PHC_INDEX

As we defined the new hwtstamp_config flag HWTSTAMP_FLAG_BONDED_PHC_INDEX
as enum, it's not easy for userspace program to check if the flag is
supported when build.

Let's define the new flag so user space could build it on old kernel with
ifdef check.

Fixes: 9c9211a3fc7a ("net_tstamp: add new flag HWTSTAMP_FLAG_BONDED_PHC_INDEX")
Signed-off-by: Hangbin Liu <[email protected]>
Acked-by: Richard Cochran <[email protected]>
Signed-off-by: Jakub Kicinski <[email protected]>

show more ...

net_tstamp: add new flag HWTSTAMP_FLAG_BONDED_PHC_INDEX

Since commit 94dd016ae538 ("bond: pass get_ts_info and SIOC[SG]HWTSTAMP
ioctl to active device") the user could get bond active interface's
PH

net_tstamp: add new flag HWTSTAMP_FLAG_BONDED_PHC_INDEX

Since commit 94dd016ae538 ("bond: pass get_ts_info and SIOC[SG]HWTSTAMP
ioctl to active device") the user could get bond active interface's
PHC index directly. But when there is a failover, the bond active
interface will change, thus the PHC index is also changed. This may
break the user's program if they did not update the PHC timely.

This patch adds a new hwtstamp_config flag HWTSTAMP_FLAG_BONDED_PHC_INDEX.
When the user wants to get the bond active interface's PHC, they need to
add this flag and be aware the PHC index may be changed.

With the new flag. All flag checks in current drivers are removed. Only
the checking in net_hwtstamp_validate() is kept.

Suggested-by: Jakub Kicinski <[email protected]>
Signed-off-by: Hangbin Liu <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net: sock: extend SO_TIMESTAMPING for PHC binding

Since PTP virtual clock support is added, there can be
several PTP virtual clocks based on one PTP physical
clock for timestamping.

This patch is t

net: sock: extend SO_TIMESTAMPING for PHC binding

Since PTP virtual clock support is added, there can be
several PTP virtual clocks based on one PTP physical
clock for timestamping.

This patch is to extend SO_TIMESTAMPING API to support
PHC (PTP Hardware Clock) binding by adding a new flag
SOF_TIMESTAMPING_BIND_PHC. When PTP virtual clocks are
in use, user space can configure to bind one for
timestamping, but PTP physical clock is not supported
and not needed to bind.

This patch is preparation for timestamp conversion from
raw timestamp to a specific PTP virtual clock time in
core net.

Signed-off-by: Yangbo Lu <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

ethtool: add timestamping related string sets

Add three string sets related to timestamping information:

ETH_SS_SOF_TIMESTAMPING: SOF_TIMESTAMPING_* flags
ETH_SS_TS_TX_TYPES: timestamping

ethtool: add timestamping related string sets

Add three string sets related to timestamping information:

ETH_SS_SOF_TIMESTAMPING: SOF_TIMESTAMPING_* flags
ETH_SS_TS_TX_TYPES: timestamping Tx types
ETH_SS_TS_RX_FILTERS: timestamping Rx filters

These will be used for TIMESTAMP_GET request.

v2: avoid compiler warning ("enumeration value not handled in switch")
in net_hwtstamp_validate()

v3: omit dash in Tx type names ("one-step-*" -> "onestep-*"), suggested by
Richard Cochran

Signed-off-by: Michal Kubecek <[email protected]>
Acked-by: Richard Cochran <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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net: Introduce peer to peer one step PTP time stamping.

The 1588 standard defines one step operation for both Sync and
PDelay_Resp messages. Up until now, hardware with P2P one step has
been rare,

net: Introduce peer to peer one step PTP time stamping.

The 1588 standard defines one step operation for both Sync and
PDelay_Resp messages. Up until now, hardware with P2P one step has
been rare, and kernel support was lacking. This patch adds support of
the mode in anticipation of new hardware developments.

Signed-off-by: Richard Cochran <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net: Use __kernel_clockid_t in uapi net_stamp.h

Herton reports the following error when building a userspace program that
includes net_stamp.h:

In file included from foo.c:2:
/usr/include/linux/n

net: Use __kernel_clockid_t in uapi net_stamp.h

Herton reports the following error when building a userspace program that
includes net_stamp.h:

In file included from foo.c:2:
/usr/include/linux/net_tstamp.h:158:2: error: unknown type name
‘clockid_t’
clockid_t clockid; /* reference clockid */
^~~~~~~~~

Fix it by using __kernel_clockid_t in place of clockid_t.

Fixes: 80b14dee2bea ("net: Add a new socket option for a future transmit time.")
Cc: Timothy Redaelli <[email protected]>
Reported-by: Herton R. Krzesinski <[email protected]>
Signed-off-by: Davide Caratti <[email protected]>
Tested-by: Paolo Abeni <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net: Use __u32 in uapi net_stamp.h

We are not supposed to use u32 in uapi, so change the flags member of
struct sock_txtime from u32 to __u32 instead.

Fixes: 80b14dee2bea ("net: Add a new socket op

net: Use __u32 in uapi net_stamp.h

We are not supposed to use u32 in uapi, so change the flags member of
struct sock_txtime from u32 to __u32 instead.

Fixes: 80b14dee2bea ("net: Add a new socket option for a future transmit time")
Reported-by: Eric Dumazet <[email protected]>
Signed-off-by: Jesus Sanchez-Palencia <[email protected]>
Reviewed-by: Eric Dumazet <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net/sched: Make etf report drops on error_queue

Use the socket error queue for reporting dropped packets if the
socket has enabled that feature through the SO_TXTIME API.

Packets are dropped either

net/sched: Make etf report drops on error_queue

Use the socket error queue for reporting dropped packets if the
socket has enabled that feature through the SO_TXTIME API.

Packets are dropped either on enqueue() if they aren't accepted by the
qdisc or on dequeue() if the system misses their deadline. Those are
reported as different errors so applications can react accordingly.

Userspace can retrieve the errors through the socket error queue and the
corresponding cmsg interfaces. A struct sock_extended_err* is used for
returning the error data, and the packet's timestamp can be retrieved by
adding both ee_data and ee_info fields as e.g.:

((__u64) serr->ee_data << 32) + serr->ee_info

This feature is disabled by default and must be explicitly enabled by
applications. Enabling it can bring some overhead for the Tx cycles
of the application.

Signed-off-by: Jesus Sanchez-Palencia <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net: Add a new socket option for a future transmit time.

This patch introduces SO_TXTIME. User space enables this option in
order to pass a desired future transmit time in a CMSG when calling
sendms

net: Add a new socket option for a future transmit time.

This patch introduces SO_TXTIME. User space enables this option in
order to pass a desired future transmit time in a CMSG when calling
sendmsg(2). The argument to this socket option is a 8-bytes long struct
provided by the uapi header net_tstamp.h defined as:

struct sock_txtime {
clockid_t clockid;
u32 flags;
};

Note that new fields were added to struct sock by filling a 2-bytes
hole found in the struct. For that reason, neither the struct size or
number of cachelines were altered.

Signed-off-by: Richard Cochran <[email protected]>
Signed-off-by: Jesus Sanchez-Palencia <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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License cleanup: add SPDX license identifier to uapi header files with no license

Many user space API headers are missing licensing information, which
makes it hard for compliance tools to determine

License cleanup: add SPDX license identifier to uapi header files with no license

Many user space API headers are missing licensing information, which
makes it hard for compliance tools to determine the correct license.

By default are files without license information under the default
license of the kernel, which is GPLV2. Marking them GPLV2 would exclude
them from being included in non GPLV2 code, which is obviously not
intended. The user space API headers fall under the syscall exception
which is in the kernels COPYING file:

NOTE! This copyright does *not* cover user programs that use kernel
services by normal system calls - this is merely considered normal use
of the kernel, and does *not* fall under the heading of "derived work".

otherwise syscall usage would not be possible.

Update the files which contain no license information with an SPDX
license identifier. The chosen identifier is 'GPL-2.0 WITH
Linux-syscall-note' which is the officially assigned identifier for the
Linux syscall exception. SPDX license identifiers are a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne. See the previous patch in this series for the
methodology of how this patch was researched.

Reviewed-by: Kate Stewart <[email protected]>
Reviewed-by: Philippe Ombredanne <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

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net: allow simultaneous SW and HW transmit timestamping

Add SOF_TIMESTAMPING_OPT_TX_SWHW option to allow an outgoing packet to
be looped to the socket's error queue with a software timestamp even
wh

net: allow simultaneous SW and HW transmit timestamping

Add SOF_TIMESTAMPING_OPT_TX_SWHW option to allow an outgoing packet to
be looped to the socket's error queue with a software timestamp even
when a hardware transmit timestamp is expected to be provided by the
driver.

Applications using this option will receive two separate messages from
the error queue, one with a software timestamp and the other with a
hardware timestamp. As the hardware timestamp is saved to the shared skb
info, which may happen before the first message with software timestamp
is received by the application, the hardware timestamp is copied to the
SCM_TIMESTAMPING control message only when the skb has no software
timestamp or it is an incoming packet.

While changing sw_tx_timestamp(), inline it in skb_tx_timestamp() as
there are no other users.

CC: Richard Cochran <[email protected]>
CC: Willem de Bruijn <[email protected]>
Signed-off-by: Miroslav Lichvar <[email protected]>
Acked-by: Willem de Bruijn <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net: add new control message for incoming HW-timestamped packets

Add SOF_TIMESTAMPING_OPT_PKTINFO option to request a new control message
for incoming packets with hardware timestamps. It contains t

net: add new control message for incoming HW-timestamped packets

Add SOF_TIMESTAMPING_OPT_PKTINFO option to request a new control message
for incoming packets with hardware timestamps. It contains the index of
the real interface which received the packet and the length of the
packet at layer 2.

The index is useful with bonding, bridges and other interfaces, where
IP_PKTINFO doesn't allow applications to determine which PHC made the
timestamp. With the L2 length (and link speed) it is possible to
transpose preamble timestamps to trailer timestamps, which are used in
the NTP protocol.

While this information could be provided by two new socket options
independently from timestamping, it doesn't look like they would be very
useful. With this option any performance impact is limited to hardware
timestamping.

Use dev_get_by_napi_id() to get the device and its index. On kernels
with disabled CONFIG_NET_RX_BUSY_POLL or drivers not using NAPI, a zero
index will be returned in the control message.

CC: Richard Cochran <[email protected]>
Acked-by: Willem de Bruijn <[email protected]>
Signed-off-by: Miroslav Lichvar <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net: define receive timestamp filter for NTP

Add HWTSTAMP_FILTER_NTP_ALL to the hwtstamp_rx_filters enum for
timestamping of NTP packets. There is currently only one driver
(phyter) that could suppo

net: define receive timestamp filter for NTP

Add HWTSTAMP_FILTER_NTP_ALL to the hwtstamp_rx_filters enum for
timestamping of NTP packets. There is currently only one driver
(phyter) that could support it directly.

CC: Richard Cochran <[email protected]>
CC: Willem de Bruijn <[email protected]>
Signed-off-by: Miroslav Lichvar <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

tcp: SOF_TIMESTAMPING_OPT_STATS option for SO_TIMESTAMPING

This patch exports the sender chronograph stats via the socket
SO_TIMESTAMPING channel. Currently we can instrument how long a
particular a

tcp: SOF_TIMESTAMPING_OPT_STATS option for SO_TIMESTAMPING

This patch exports the sender chronograph stats via the socket
SO_TIMESTAMPING channel. Currently we can instrument how long a
particular application unit of data was queued in TCP by tracking
SOF_TIMESTAMPING_TX_SOFTWARE and SOF_TIMESTAMPING_TX_SCHED. Having
these sender chronograph stats exported simultaneously along with
these timestamps allow further breaking down the various sender
limitation. For example, a video server can tell if a particular
chunk of video on a connection takes a long time to deliver because
TCP was experiencing small receive window. It is not possible to
tell before this patch without packet traces.

To prepare these stats, the user needs to set
SOF_TIMESTAMPING_OPT_STATS and SOF_TIMESTAMPING_OPT_TSONLY flags
while requesting other SOF_TIMESTAMPING TX timestamps. When the
timestamps are available in the error queue, the stats are returned
in a separate control message of type SCM_TIMESTAMPING_OPT_STATS,
in a list of TLVs (struct nlattr) of types: TCP_NLA_BUSY_TIME,
TCP_NLA_RWND_LIMITED, TCP_NLA_SNDBUF_LIMITED. Unit is microsecond.

Signed-off-by: Francis Yan <[email protected]>
Signed-off-by: Yuchung Cheng <[email protected]>
Signed-off-by: Soheil Hassas Yeganeh <[email protected]>
Acked-by: Neal Cardwell <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

sock: accept SO_TIMESTAMPING flags in socket cmsg

Accept SO_TIMESTAMPING in control messages of the SOL_SOCKET level
as a basis to accept timestamping requests per write.

This implementation only a

sock: accept SO_TIMESTAMPING flags in socket cmsg

Accept SO_TIMESTAMPING in control messages of the SOL_SOCKET level
as a basis to accept timestamping requests per write.

This implementation only accepts TX recording flags (i.e.,
SOF_TIMESTAMPING_TX_HARDWARE, SOF_TIMESTAMPING_TX_SOFTWARE,
SOF_TIMESTAMPING_TX_SCHED, and SOF_TIMESTAMPING_TX_ACK) in
control messages. Users need to set reporting flags (e.g.,
SOF_TIMESTAMPING_OPT_ID) per socket via socket options.

This commit adds a tsflags field in sockcm_cookie which is
set in __sock_cmsg_send. It only override the SOF_TIMESTAMPING_TX_*
bits in sockcm_cookie.tsflags allowing the control message
to override the recording behavior per write, yet maintaining
the value of other flags.

This patch implements validating the control message and setting
tsflags in struct sockcm_cookie. Next commits in this series will
actually implement timestamping per write for different protocols.

Signed-off-by: Soheil Hassas Yeganeh <[email protected]>
Acked-by: Willem de Bruijn <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

show more ...

net-timestamp: no-payload option

Add timestamping option SOF_TIMESTAMPING_OPT_TSONLY. For transmit
timestamps, this loops timestamps on top of empty packets.

Doing so reduces the pressure on SO_RCV

net-timestamp: no-payload option

Add timestamping option SOF_TIMESTAMPING_OPT_TSONLY. For transmit
timestamps, this loops timestamps on top of empty packets.

Doing so reduces the pressure on SO_RCVBUF. Payload inspection and
cmsg reception (aside from timestamps) are no longer possible. This
works together with a follow on patch that allows administrators to
only allow tx timestamping if it does not loop payload or metadata.

Signed-off-by: Willem de Bruijn <[email protected]>

----

Changes (rfc -> v1)
- add documentation
- remove unnecessary skb->len test (thanks to Richard Cochran)
Signed-off-by: David S. Miller <[email protected]>

show more ...

net-timestamp: allow reading recv cmsg on errqueue with origin tstamp

Allow reading of timestamps and cmsg at the same time on all relevant
socket families. One use is to correlate timestamps with e

net-timestamp: allow reading recv cmsg on errqueue with origin tstamp

Allow reading of timestamps and cmsg at the same time on all relevant
socket families. One use is to correlate timestamps with egress
device, by asking for cmsg IP_PKTINFO.

on AF_INET sockets, call the relevant function (ip_cmsg_recv). To
avoid changing legacy expectations, only do so if the caller sets a
new timestamping flag SOF_TIMESTAMPING_OPT_CMSG.

on AF_INET6 sockets, IPV6_PKTINFO and all other recv cmsg are already
returned for all origins. only change is to set ifindex, which is
not initialized for all error origins.

In both cases, only generate the pktinfo message if an ifindex is
known. This is not the case for ACK timestamps.

The difference between the protocol families is probably a historical
accident as a result of the different conditions for generating cmsg
in the relevant ip(v6)_recv_error function:

ipv4: if (serr->ee.ee_origin == SO_EE_ORIGIN_ICMP) {
ipv6: if (serr->ee.ee_origin != SO_EE_ORIGIN_LOCAL) {

At one time, this was the same test bar for the ICMP/ICMP6
distinction. This is no longer true.

Signed-off-by: Willem de Bruijn <[email protected]>

----

Changes
v1 -> v2
large rewrite
- integrate with existing pktinfo cmsg generation code
- on ipv4: only send with new flag, to maintain legacy behavior
- on ipv6: send at most a single pktinfo cmsg
- on ipv6: initialize fields if not yet initialized

The recv cmsg interfaces are also relevant to the discussion of
whether looping packet headers is problematic. For v6, cmsgs that
identify many headers are already returned. This patch expands
that to v4. If it sounds reasonable, I will follow with patches

1. request timestamps without payload with SOF_TIMESTAMPING_OPT_TSONLY
(http://patchwork.ozlabs.org/patch/366967/)
2. sysctl to conditionally drop all timestamps that have payload or
cmsg from users without CAP_NET_RAW.
Signed-off-by: David S. Miller <[email protected]>

show more ...

net-timestamp: ACK timestamp for bytestreams

Add SOF_TIMESTAMPING_TX_ACK, a request for a tstamp when the last byte
in the send() call is acknowledged. It implements the feature for TCP.

The timest

net-timestamp: ACK timestamp for bytestreams

Add SOF_TIMESTAMPING_TX_ACK, a request for a tstamp when the last byte
in the send() call is acknowledged. It implements the feature for TCP.

The timestamp is generated when the TCP socket cumulative ACK is moved
beyond the tracked seqno for the first time. The feature ignores SACK
and FACK, because those acknowledge the specific byte, but not
necessarily the entire contents of the buffer up to that byte.

Signed-off-by: Willem de Bruijn <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

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