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2020-04-30docs: networking: convert timestamping.txt to ReSTMauro Carvalho Chehab
- add SPDX header; - add a document title; - adjust titles and chapters, adding proper markups; - mark code blocks and literals as such; - adjust identation, whitespaces and blank lines where needed; - add to networking/index.rst. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-06-14docs: ptp.txt: convert to ReST and move to driver-apiMauro Carvalho Chehab
The conversion is trivial: just adjust title markups. In order to avoid conflicts, let's add an :orphan: tag to it, to be removed when this file gets added to the driver-api book. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Acked-by: Richard Cochran <richardcochran@gmail.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2019-02-03socket: Update timestamping DocumentationDeepa Dinamani
With the new y2038 safe timestamping options added, update the documentation to reflect the changes. Signed-off-by: Deepa Dinamani <deepa.kernel@gmail.com> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-01-17Documentation: timestamping: correct path to net_tstamp.hJakub Kicinski
net_tstamp.h is an UAPI header, so it was moved under include/uapi. Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-07-11net: Fix minor code bug in timestamping.txtAhmad Fatoum
Passing (void*)val instead of &val would make a pointer out of an integer and cause sock_setsockopt to -EFAULT. See tools/testing/selftests/networking/timestamping/timestamping.c for a working example. Cc: David S. Miller <davem@davemloft.net> Cc: netdev@vger.kernel.org Signed-off-by: Ahmad Fatoum <ahmad@a3f.at> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-21net: allow simultaneous SW and HW transmit timestampingMiroslav Lichvar
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 <richardcochran@gmail.com> CC: Willem de Bruijn <willemb@google.com> Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-21net: fix documentation of struct scm_timestampingMiroslav Lichvar
The scm_timestamping struct may return multiple non-zero fields, e.g. when both software and hardware RX timestamping is enabled, or when the SO_TIMESTAMP(NS) option is combined with SCM_TIMESTAMPING and a false software timestamp is generated in the recvmsg() call in order to always return a SCM_TIMESTAMP(NS) message. CC: Richard Cochran <richardcochran@gmail.com> CC: Willem de Bruijn <willemb@google.com> Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2017-05-21net: add new control message for incoming HW-timestamped packetsMiroslav Lichvar
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 <richardcochran@gmail.com> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-11-30tcp: SOF_TIMESTAMPING_OPT_STATS option for SO_TIMESTAMPINGFrancis Yan
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 <francisyyan@gmail.com> Signed-off-by: Yuchung Cheng <ycheng@google.com> Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Acked-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-04sock: document timestamping via cmsg in DocumentationSoheil Hassas Yeganeh
Update docs and add code snippet for using cmsg for timestamping. Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2015-07-17clarify implementation of ethtool's get_ts_info opJacob Keller
This patch adds some clarification about the intended way to implement both SIOCSHWTSTAMP and ethtool's get_ts_info. The HWTSTAMP API has several Rx filters which are very specific, as well as more general filters. The specific filters really only exist to support some broken hardware which can't fully implement the generic filters. This patch adds clarification that it is okay to support the specific filters in SIOCSHWTSTAMP by upscaling them to the generic filters. In addition, update the header for ethtool_ts_info to specify that drivers ought to only report the filters they support without upscaling in this manner. Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> Acked-by: Richard Cochran <richardcochran@gmail.com> Tested-by: Phil Schmitt <phillip.j.schmitt@intel.com> Reviewed-by: Aaron Brown <aaron.f.brown@intel.com> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
2015-02-02net-timestamp: no-payload optionWillem de Bruijn
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 <willemb@google.com> ---- Changes (rfc -> v1) - add documentation - remove unnecessary skb->len test (thanks to Richard Cochran) Signed-off-by: David S. Miller <davem@davemloft.net>
2014-12-08net-timestamp: expand documentation and testWillem de Bruijn
Documentation: expand explanation of timestamp counter Test: new: flag -I requests and prints PKTINFO new: flag -x prints payload (possibly truncated) fix: remove pretty print that breaks common flag '-l 1' Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-12-08net-timestamp: allow reading recv cmsg on errqueue with origin tstampWillem de Bruijn
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 <willemb@google.com> ---- 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 <davem@davemloft.net>
2014-11-25net-timestamp: Fix a documentation typoAndrew Lutomirski
SOF_TIMESTAMPING_OPT_ID puts the id in ee_data, not ee_info. Cc: Willem de Bruijn <willemb@google.com> Signed-off-by: Andy Lutomirski <luto@amacapital.net> Acked-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-01net-timestamp: expand documentationWillem de Bruijn
Expand Documentation/networking/timestamping.txt with new interfaces and bytestream timestamping. Also minor cleanup of the other text. Import txtimestamp.c test of the new features. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-07-29net: remove deprecated syststamp timestampWillem de Bruijn
The SO_TIMESTAMPING API defines three types of timestamps: software, hardware in raw format (hwtstamp) and hardware converted to system format (syststamp). The last has been deprecated in favor of combining hwtstamp with a PTP clock driver. There are no active users in the kernel. The option was device driver dependent. If set, but without hardware support, the correct behavior is to return zero in the relevant field in the SCM_TIMESTAMPING ancillary message. Without device drivers implementing the option, this field is effectively always zero. Remove the internal plumbing to dissuage new drivers from implementing the feature. Keep the SOF_TIMESTAMPING_SYS_HARDWARE flag, however, to avoid breaking existing applications that request the timestamp. Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-07-15net-timestamp: document deprecated syststampWillem de Bruijn
The SO_TIMESTAMPING API defines option SOF_TIMESTAMPING_SYS_HW. This feature is deprecated. It should not be implemented by new device drivers. Existing drivers do not implement it, either -- with one exception. Driver developers are encouraged to expose the NIC hw clock as a PTP HW clock source, instead, and synchronize system time to the HW source. The control flag cannot be removed due to being part of the ABI, nor can the structure scm_timestamping that is returned. Due to the one legacy driver, the internal datapath and structure are not removed. This patch only clearly marks the interface as deprecated. Device drivers should always return a syststamp value of zero. Signed-off-by: Willem de Bruijn <willemb@google.com> ---- We can consider adding a WARN_ON_ONCE in__sock_recv_timestamp if non-zero syststamp is encountered Acked-by: Richard Cochran <richardcochran@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-18doc: update driver TX algorithm in timestamping.txtJakub Kicinski
Since cd4d8fdad1f1 ("net: kernel panic in dev_hard_start_xmit: remove faulty software TX time stamping") dev_hard_start_xmit() will not provide software timestamps. It's a responsibility of the drivers to call skb_tx_timestamp() at the right time. Cc: linux-doc@vger.kernel.org Signed-off-by: Jakub Kicinski <kubakici@wp.pl> Signed-off-by: David S. Miller <davem@davemloft.net>
2014-03-06net: Improve SO_TIMESTAMPING documentation and fix a minor code bugAndrew Lutomirski
The original documentation was very unclear. The code fix is presumably related to the formerly unclear documentation: SOCK_TIMESTAMPING_RX_SOFTWARE has no effect on __sock_recv_timestamp's behavior, so calling __sock_recv_ts_and_drops from sock_recv_ts_and_drops if only SOCK_TIMESTAMPING_RX_SOFTWARE is set is pointless. This should have no user-observable effect. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Acked-by: Richard Cochran <richardcochran@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2013-11-19net_tstamp: Add SIOCGHWTSTAMP ioctl to match SIOCSHWTSTAMPBen Hutchings
SIOCSHWTSTAMP returns the real configuration to the application using it, but there is currently no way for any other application to find out the configuration non-destructively. Add a new ioctl for this, making it unprivileged. Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
2010-08-19net: simplify flags for tx timestampingOliver Hartkopp
This patch removes the abstraction introduced by the union skb_shared_tx in the shared skb data. The access of the different union elements at several places led to some confusion about accessing the shared tx_flags e.g. in skb_orphan_try(). http://marc.info/?l=linux-netdev&m=128084897415886&w=2 Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2010-04-07net: corrected documentation for hardware time stampingPatrick Loschmidt
The current documentation for hardware time stamping does not correctly specify the available kernel functions since the implementation was changed later on. Signed-off-by: Patrick Loschmidt <Patrick.Loschmidt@oeaw.ac.at> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-02-15ip: support for TX timestamps on UDP and RAW socketsPatrick Ohly
Instructions for time stamping outgoing packets are take from the socket layer and later copied into the new skb. Signed-off-by: Patrick Ohly <patrick.ohly@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2009-02-15net: new user space API for time stamping of incoming and outgoing packetsPatrick Ohly
User space can request hardware and/or software time stamping. Reporting of the result(s) via a new control message is enabled separately for each field in the message because some of the fields may require additional computation and thus cause overhead. User space can tell the different kinds of time stamps apart and choose what suits its needs. When a TX timestamp operation is requested, the TX skb will be cloned and the clone will be time stamped (in hardware or software) and added to the socket error queue of the skb, if the skb has a socket associated with it. The actual TX timestamp will reach userspace as a RX timestamp on the cloned packet. If timestamping is requested and no timestamping is done in the device driver (potentially this may use hardware timestamping), it will be done in software after the device's start_hard_xmit routine. Signed-off-by: Patrick Ohly <patrick.ohly@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>