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Commit f24b9be5 authored by Willem de Bruijn's avatar Willem de Bruijn Committed by David S. Miller
Browse files

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: default avatarWillem de Bruijn <willemb@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent a2b81b35

include/linux/skbuff.h

+3 −0
Original line number Diff line number Diff line
@@ -249,6 +249,9 @@ enum { 
	SKBTX_SHARED_FRAG = 1 << 5,

};



#define SKBTX_ANY_SW_TSTAMP	SKBTX_SW_TSTAMP

#define SKBTX_ANY_TSTAMP	(SKBTX_HW_TSTAMP | SKBTX_ANY_SW_TSTAMP)



/*

 * The callback notifies userspace to release buffers when skb DMA is done in

 * lower device, the skb last reference should be 0 when calling this.

include/net/sock.h

+3 −1
Original line number Diff line number Diff line
@@ -2169,7 +2169,9 @@ sock_recv_timestamp(struct msghdr *msg, struct sock *sk, struct sk_buff *skb) 
	 */

	if (sock_flag(sk, SOCK_RCVTSTAMP) ||

	    sock_flag(sk, SOCK_TIMESTAMPING_RX_SOFTWARE) ||

	    (kt.tv64 && sock_flag(sk, SOCK_TIMESTAMPING_SOFTWARE)) ||

	    (kt.tv64 &&

	     (sock_flag(sk, SOCK_TIMESTAMPING_SOFTWARE) ||

	      skb_shinfo(skb)->tx_flags & SKBTX_ANY_SW_TSTAMP)) ||

	    (hwtstamps->hwtstamp.tv64 &&

	     sock_flag(sk, SOCK_TIMESTAMPING_RAW_HARDWARE)))

		__sock_recv_timestamp(msg, sk, skb);

include/uapi/linux/errqueue.h

+18 −0
Original line number Diff line number Diff line
@@ -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 */

net/core/skbuff.c

+1 −0
Original line number Diff line number Diff line
@@ -3521,6 +3521,7 @@ void skb_tstamp_tx(struct sk_buff *orig_skb, 
	memset(serr, 0, sizeof(*serr));

	serr->ee.ee_errno = ENOMSG;

	serr->ee.ee_origin = SO_EE_ORIGIN_TIMESTAMPING;

	serr->ee.ee_info = SCM_TSTAMP_SND;



	err = sock_queue_err_skb(sk, skb);

net/socket.c

+11 −9
Original line number Diff line number Diff line
@@ -106,6 +106,7 @@ 
#include <linux/sockios.h>

#include <linux/atalk.h>

#include <net/busy_poll.h>

#include <linux/errqueue.h>



#ifdef CONFIG_NET_RX_BUSY_POLL

unsigned int sysctl_net_busy_read __read_mostly;
@@ -697,7 +698,7 @@ void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk, 
	struct sk_buff *skb)

{

	int need_software_tstamp = sock_flag(sk, SOCK_RCVTSTAMP);

	struct timespec ts[3];

	struct scm_timestamping tss;

	int empty = 1;

	struct skb_shared_hwtstamps *shhwtstamps =

		skb_hwtstamps(skb);
@@ -714,24 +715,25 @@ void __sock_recv_timestamp(struct msghdr *msg, struct sock *sk, 
			put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMP,

				 sizeof(tv), &tv);

		} else {

			skb_get_timestampns(skb, &ts[0]);

			struct timespec ts;

			skb_get_timestampns(skb, &ts);

			put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMPNS,

				 sizeof(ts[0]), &ts[0]);

				 sizeof(ts), &ts);

		}

	}





	memset(ts, 0, sizeof(ts));

	if (sock_flag(sk, SOCK_TIMESTAMPING_SOFTWARE) &&

	    ktime_to_timespec_cond(skb->tstamp, ts + 0))

	memset(&tss, 0, sizeof(tss));

	if ((sock_flag(sk, SOCK_TIMESTAMPING_SOFTWARE) ||

	     skb_shinfo(skb)->tx_flags & SKBTX_ANY_SW_TSTAMP) &&

	    ktime_to_timespec_cond(skb->tstamp, tss.ts + 0))

		empty = 0;

	if (shhwtstamps &&

	    sock_flag(sk, SOCK_TIMESTAMPING_RAW_HARDWARE) &&

	    ktime_to_timespec_cond(shhwtstamps->hwtstamp, ts + 2))

	    ktime_to_timespec_cond(shhwtstamps->hwtstamp, tss.ts + 2))

		empty = 0;

	if (!empty)

		put_cmsg(msg, SOL_SOCKET,

			 SCM_TIMESTAMPING, sizeof(ts), &ts);

			 SCM_TIMESTAMPING, sizeof(tss), &tss);

}

EXPORT_SYMBOL_GPL(__sock_recv_timestamp);