From f24b9be5957b38bb420b838115040dc2031b7d0c Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Mon, 4 Aug 2014 22:11:45 -0400 Subject: net-timestamp: extend SCM_TIMESTAMPING ancillary data struct Applications that request kernel tx timestamps with SO_TIMESTAMPING read timestamps as recvmsg() ancillary data. The response is defined implicitly as timespec[3]. 1) define struct scm_timestamping explicitly and 2) add support for new tstamp types. On tx, scm_timestamping always accompanies a sock_extended_err. Define previously unused field ee_info to signal the type of ts[0]. Introduce SCM_TSTAMP_SND to define the existing behavior. The reception path is not modified. On rx, no struct similar to sock_extended_err is passed along with SCM_TIMESTAMPING. Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller --- include/uapi/linux/errqueue.h | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) (limited to 'include/uapi') diff --git a/include/uapi/linux/errqueue.h b/include/uapi/linux/errqueue.h index aacd4fb7102a..accee72cae7c 100644 --- a/include/uapi/linux/errqueue.h +++ b/include/uapi/linux/errqueue.h @@ -22,5 +22,23 @@ struct sock_extended_err { #define SO_EE_OFFENDER(ee) ((struct sockaddr*)((ee)+1)) +/** + * struct scm_timestamping - timestamps exposed through cmsg + * + * The timestamping interfaces SO_TIMESTAMPING, MSG_TSTAMP_* + * communicate network timestamps by passing this struct in a cmsg with + * recvmsg(). See Documentation/networking/timestamping.txt for details. + */ +struct scm_timestamping { + struct timespec ts[3]; +}; + +/* The type of scm_timestamping, passed in sock_extended_err ee_info. + * This defines the type of ts[0]. For SCM_TSTAMP_SND only, if ts[0] + * is zero, then this is a hardware timestamp and recorded in ts[2]. + */ +enum { + SCM_TSTAMP_SND, /* driver passed skb to NIC, or HW */ +}; #endif /* _UAPI_LINUX_ERRQUEUE_H */ -- cgit v1.2.2 From 09c2d251b70723650ba47e83571ff49281320f7c Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Mon, 4 Aug 2014 22:11:47 -0400 Subject: net-timestamp: add key to disambiguate concurrent datagrams Datagrams timestamped on transmission can coexist in the kernel stack and be reordered in packet scheduling. When reading looped datagrams from the socket error queue it is not always possible to unique correlate looped data with original send() call (for application level retransmits). Even if possible, it may be expensive and complex, requiring packet inspection. Introduce a data-independent ID mechanism to associate timestamps with send calls. Pass an ID alongside the timestamp in field ee_data of sock_extended_err. The ID is a simple 32 bit unsigned int that is associated with the socket and incremented on each send() call for which software tx timestamp generation is enabled. The feature is enabled only if SOF_TIMESTAMPING_OPT_ID is set, to avoid changing ee_data for existing applications that expect it 0. The counter is reset each time the flag is reenabled. Reenabling does not change the ID of already submitted data. It is possible to receive out of order IDs if the timestamp stream is not quiesced first. Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller --- include/uapi/linux/net_tstamp.h | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'include/uapi') diff --git a/include/uapi/linux/net_tstamp.h b/include/uapi/linux/net_tstamp.h index f53879c0f590..1e861d2e1a31 100644 --- a/include/uapi/linux/net_tstamp.h +++ b/include/uapi/linux/net_tstamp.h @@ -20,9 +20,11 @@ enum { SOF_TIMESTAMPING_SOFTWARE = (1<<4), SOF_TIMESTAMPING_SYS_HARDWARE = (1<<5), SOF_TIMESTAMPING_RAW_HARDWARE = (1<<6), - SOF_TIMESTAMPING_MASK = - (SOF_TIMESTAMPING_RAW_HARDWARE - 1) | - SOF_TIMESTAMPING_RAW_HARDWARE + SOF_TIMESTAMPING_OPT_ID = (1<<7), + + SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_OPT_ID, + SOF_TIMESTAMPING_MASK = (SOF_TIMESTAMPING_LAST - 1) | + SOF_TIMESTAMPING_LAST }; /** -- cgit v1.2.2 From e7fd2885385157d46c85f282fc6d7d297db43e1f Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Mon, 4 Aug 2014 22:11:48 -0400 Subject: net-timestamp: SCHED timestamp on entering packet scheduler Kernel transmit latency is often incurred in the packet scheduler. Introduce a new timestamp on transmission just before entering the scheduler. When data travels through multiple devices (bonding, tunneling, ...) each device will export an individual timestamp. Signed-off-by: Willem de Bruijn Signed-off-by: David S. Miller --- include/uapi/linux/errqueue.h | 1 + include/uapi/linux/net_tstamp.h | 3 ++- 2 files changed, 3 insertions(+), 1 deletion(-) (limited to 'include/uapi') diff --git a/include/uapi/linux/errqueue.h b/include/uapi/linux/errqueue.h index accee72cae7c..17437cf297b7 100644 --- a/include/uapi/linux/errqueue.h +++ b/include/uapi/linux/errqueue.h @@ -39,6 +39,7 @@ struct scm_timestamping { */ enum { SCM_TSTAMP_SND, /* driver passed skb to NIC, or HW */ + SCM_TSTAMP_SCHED, /* data entered the packet scheduler */ }; #endif /* _UAPI_LINUX_ERRQUEUE_H */ diff --git a/include/uapi/linux/net_tstamp.h b/include/uapi/linux/net_tstamp.h index 1e861d2e1a31..60733845fcdd 100644 --- a/include/uapi/linux/net_tstamp.h +++ b/include/uapi/linux/net_tstamp.h @@ -21,8 +21,9 @@ enum { SOF_TIMESTAMPING_SYS_HARDWARE = (1<<5), SOF_TIMESTAMPING_RAW_HARDWARE = (1<<6), SOF_TIMESTAMPING_OPT_ID = (1<<7), + SOF_TIMESTAMPING_TX_SCHED = (1<<8), - SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_OPT_ID, + SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_TX_SCHED, SOF_TIMESTAMPING_MASK = (SOF_TIMESTAMPING_LAST - 1) | SOF_TIMESTAMPING_LAST }; -- cgit v1.2.2 From e1c8a607b28190cd09a271508aa3025d3c2f312e Mon Sep 17 00:00:00 2001 From: Willem de Bruijn Date: Mon, 4 Aug 2014 22:11:50 -0400 Subject: 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 Signed-off-by: David S. Miller --- include/uapi/linux/errqueue.h | 1 + include/uapi/linux/net_tstamp.h | 3 ++- 2 files changed, 3 insertions(+), 1 deletion(-) (limited to 'include/uapi') diff --git a/include/uapi/linux/errqueue.h b/include/uapi/linux/errqueue.h index 17437cf297b7..07bdce1f444a 100644 --- a/include/uapi/linux/errqueue.h +++ b/include/uapi/linux/errqueue.h @@ -40,6 +40,7 @@ struct scm_timestamping { enum { SCM_TSTAMP_SND, /* driver passed skb to NIC, or HW */ SCM_TSTAMP_SCHED, /* data entered the packet scheduler */ + SCM_TSTAMP_ACK, /* data acknowledged by peer */ }; #endif /* _UAPI_LINUX_ERRQUEUE_H */ diff --git a/include/uapi/linux/net_tstamp.h b/include/uapi/linux/net_tstamp.h index 60733845fcdd..ff354021bb69 100644 --- a/include/uapi/linux/net_tstamp.h +++ b/include/uapi/linux/net_tstamp.h @@ -22,8 +22,9 @@ enum { SOF_TIMESTAMPING_RAW_HARDWARE = (1<<6), SOF_TIMESTAMPING_OPT_ID = (1<<7), SOF_TIMESTAMPING_TX_SCHED = (1<<8), + SOF_TIMESTAMPING_TX_ACK = (1<<9), - SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_TX_SCHED, + SOF_TIMESTAMPING_LAST = SOF_TIMESTAMPING_TX_ACK, SOF_TIMESTAMPING_MASK = (SOF_TIMESTAMPING_LAST - 1) | SOF_TIMESTAMPING_LAST }; -- cgit v1.2.2