Commit 2e31396f authored by Willem de Bruijn's avatar Willem de Bruijn Committed by David S. Miller
Browse files

packet: tx timestamping on tpacket ring 



When transmit timestamping is enabled at the socket level, record a
timestamp on packets written to a PACKET_TX_RING. Tx timestamps are
always looped to the application over the socket error queue. Software
timestamps are also written back into the packet frame header in the
packet ring.

Reported-by: default avatarPaul Chavent <paul.chavent@onera.fr>
Signed-off-by: default avatarWillem de Bruijn <willemb@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 92dea7c0

net/core/skbuff.c

+6 −6
Original line number Diff line number Diff line
@@ -3327,12 +3327,8 @@ void skb_tstamp_tx(struct sk_buff *orig_skb, 
	if (!sk)

		return;



	skb = skb_clone(orig_skb, GFP_ATOMIC);

	if (!skb)

		return;



	if (hwtstamps) {

		*skb_hwtstamps(skb) =

		*skb_hwtstamps(orig_skb) =

			*hwtstamps;

	} else {

		/*
@@ -3340,9 +3336,13 @@ void skb_tstamp_tx(struct sk_buff *orig_skb, 
		 * so keep the shared tx_flags and only

		 * store software time stamp

		 */

		skb->tstamp = ktime_get_real();

		orig_skb->tstamp = ktime_get_real();

	}



	skb = skb_clone(orig_skb, GFP_ATOMIC);

	if (!skb)

		return;



	serr = SKB_EXT_ERR(skb);

	memset(serr, 0, sizeof(*serr));

	serr->ee.ee_errno = ENOMSG;

net/packet/af_packet.c

+33 −0
Original line number Diff line number Diff line
@@ -339,6 +339,37 @@ static int __packet_get_status(struct packet_sock *po, void *frame) 
	}

}



static void __packet_set_timestamp(struct packet_sock *po, void *frame,

				   ktime_t tstamp)

{

	union tpacket_uhdr h;

	struct timespec ts;



	if (!ktime_to_timespec_cond(tstamp, &ts) ||

	    !sock_flag(&po->sk, SOCK_TIMESTAMPING_SOFTWARE))

		return;



	h.raw = frame;

	switch (po->tp_version) {

	case TPACKET_V1:

		h.h1->tp_sec = ts.tv_sec;

		h.h1->tp_usec = ts.tv_nsec / NSEC_PER_USEC;

		break;

	case TPACKET_V2:

		h.h2->tp_sec = ts.tv_sec;

		h.h2->tp_nsec = ts.tv_nsec;

		break;

	case TPACKET_V3:

	default:

		WARN(1, "TPACKET version not supported.\n");

		BUG();

	}



	/* one flush is safe, as both fields always lie on the same cacheline */

	flush_dcache_page(pgv_to_page(&h.h1->tp_sec));

	smp_wmb();

}



static void *packet_lookup_frame(struct packet_sock *po,

		struct packet_ring_buffer *rb,

		unsigned int position,
@@ -1877,6 +1908,7 @@ static void tpacket_destruct_skb(struct sk_buff *skb) 
		ph = skb_shinfo(skb)->destructor_arg;

		BUG_ON(atomic_read(&po->tx_ring.pending) == 0);

		atomic_dec(&po->tx_ring.pending);

		__packet_set_timestamp(po, ph, skb->tstamp);

		__packet_set_status(po, ph, TP_STATUS_AVAILABLE);

	}
@@ -1900,6 +1932,7 @@ static int tpacket_fill_skb(struct packet_sock *po, struct sk_buff *skb, 
	skb->dev = dev;

	skb->priority = po->sk.sk_priority;

	skb->mark = po->sk.sk_mark;

	sock_tx_timestamp(&po->sk, &skb_shinfo(skb)->tx_flags);

	skb_shinfo(skb)->destructor_arg = ph.raw;



	switch (po->tp_version) {

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