Commit 2fd66ffb authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

tcp: introduce tcp_skb_timestamp_us() helper 



There are few places where TCP reads skb->skb_mstamp expecting
a value in usec unit.

skb->tstamp (aka skb->skb_mstamp) will soon store CLOCK_TAI nsec value.

Add tcp_skb_timestamp_us() to provide proper conversion when needed.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 72b0094f

include/net/tcp.h

+7 −1
Original line number Diff line number Diff line
@@ -774,6 +774,12 @@ static inline u32 tcp_skb_timestamp(const struct sk_buff *skb) 
	return div_u64(skb->skb_mstamp, USEC_PER_SEC / TCP_TS_HZ);

}



/* provide the departure time in us unit */

static inline u64 tcp_skb_timestamp_us(const struct sk_buff *skb)

{

	return skb->skb_mstamp;

}





#define tcp_flag_byte(th) (((u_int8_t *)th)[13])
@@ -1940,7 +1946,7 @@ static inline s64 tcp_rto_delta_us(const struct sock *sk) 
{

	const struct sk_buff *skb = tcp_rtx_queue_head(sk);

	u32 rto = inet_csk(sk)->icsk_rto;

	u64 rto_time_stamp_us = skb->skb_mstamp + jiffies_to_usecs(rto);

	u64 rto_time_stamp_us = tcp_skb_timestamp_us(skb) + jiffies_to_usecs(rto);



	return rto_time_stamp_us - tcp_sk(sk)->tcp_mstamp;

}

net/ipv4/tcp_input.c

+6 −5
Original line number Diff line number Diff line
@@ -1305,7 +1305,7 @@ static bool tcp_shifted_skb(struct sock *sk, struct sk_buff *prev, 
	 */

	tcp_sacktag_one(sk, state, TCP_SKB_CB(skb)->sacked,

			start_seq, end_seq, dup_sack, pcount,

			skb->skb_mstamp);

			tcp_skb_timestamp_us(skb));

	tcp_rate_skb_delivered(sk, skb, state->rate);



	if (skb == tp->lost_skb_hint)
@@ -1580,7 +1580,7 @@ static struct sk_buff *tcp_sacktag_walk(struct sk_buff *skb, struct sock *sk, 
						TCP_SKB_CB(skb)->end_seq,

						dup_sack,

						tcp_skb_pcount(skb),

						skb->skb_mstamp);

						tcp_skb_timestamp_us(skb));

			tcp_rate_skb_delivered(sk, skb, state->rate);

			if (TCP_SKB_CB(skb)->sacked & TCPCB_SACKED_ACKED)

				list_del_init(&skb->tcp_tsorted_anchor);
@@ -3103,7 +3103,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, u32 prior_fack, 
				tp->retrans_out -= acked_pcount;

			flag |= FLAG_RETRANS_DATA_ACKED;

		} else if (!(sacked & TCPCB_SACKED_ACKED)) {

			last_ackt = skb->skb_mstamp;

			last_ackt = tcp_skb_timestamp_us(skb);

			WARN_ON_ONCE(last_ackt == 0);

			if (!first_ackt)

				first_ackt = last_ackt;
@@ -3121,7 +3121,7 @@ static int tcp_clean_rtx_queue(struct sock *sk, u32 prior_fack, 
			tp->delivered += acked_pcount;

			if (!tcp_skb_spurious_retrans(tp, skb))

				tcp_rack_advance(tp, sacked, scb->end_seq,

						 skb->skb_mstamp);

						 tcp_skb_timestamp_us(skb));

		}

		if (sacked & TCPCB_LOST)

			tp->lost_out -= acked_pcount;
@@ -3215,7 +3215,8 @@ static int tcp_clean_rtx_queue(struct sock *sk, u32 prior_fack, 
			tp->lost_cnt_hint -= min(tp->lost_cnt_hint, delta);

		}

	} else if (skb && rtt_update && sack_rtt_us >= 0 &&

		   sack_rtt_us > tcp_stamp_us_delta(tp->tcp_mstamp, skb->skb_mstamp)) {

		   sack_rtt_us > tcp_stamp_us_delta(tp->tcp_mstamp,

						    tcp_skb_timestamp_us(skb))) {

		/* Do not re-arm RTO if the sack RTT is measured from data sent

		 * after when the head was last (re)transmitted. Otherwise the

		 * timeout may continue to extend in loss recovery.

net/ipv4/tcp_ipv4.c

+1 −1
Original line number Diff line number Diff line
@@ -544,7 +544,7 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info) 
		BUG_ON(!skb);



		tcp_mstamp_refresh(tp);

		delta_us = (u32)(tp->tcp_mstamp - skb->skb_mstamp);

		delta_us = (u32)(tp->tcp_mstamp - tcp_skb_timestamp_us(skb));

		remaining = icsk->icsk_rto -

			    usecs_to_jiffies(delta_us);

net/ipv4/tcp_output.c

+1 −1
Original line number Diff line number Diff line
@@ -1966,7 +1966,7 @@ static bool tcp_tso_should_defer(struct sock *sk, struct sk_buff *skb, 
	head = tcp_rtx_queue_head(sk);

	if (!head)

		goto send_now;

	age = tcp_stamp_us_delta(tp->tcp_mstamp, head->skb_mstamp);

	age = tcp_stamp_us_delta(tp->tcp_mstamp, tcp_skb_timestamp_us(head));

	/* If next ACK is likely to come too late (half srtt), do not defer */

	if (age < (tp->srtt_us >> 4))

		goto send_now;

net/ipv4/tcp_rate.c

+8 −7
Original line number Diff line number Diff line
@@ -55,8 +55,10 @@ void tcp_rate_skb_sent(struct sock *sk, struct sk_buff *skb) 
	  * bandwidth estimate.

	  */

	if (!tp->packets_out) {

		tp->first_tx_mstamp  = skb->skb_mstamp;

		tp->delivered_mstamp = skb->skb_mstamp;

		u64 tstamp_us = tcp_skb_timestamp_us(skb);



		tp->first_tx_mstamp  = tstamp_us;

		tp->delivered_mstamp = tstamp_us;

	}



	TCP_SKB_CB(skb)->tx.first_tx_mstamp	= tp->first_tx_mstamp;
@@ -88,13 +90,12 @@ void tcp_rate_skb_delivered(struct sock *sk, struct sk_buff *skb, 
		rs->is_app_limited   = scb->tx.is_app_limited;

		rs->is_retrans	     = scb->sacked & TCPCB_RETRANS;



		/* Record send time of most recently ACKed packet: */

		tp->first_tx_mstamp  = tcp_skb_timestamp_us(skb);

		/* Find the duration of the "send phase" of this window: */

		rs->interval_us      = tcp_stamp_us_delta(

						skb->skb_mstamp,

		rs->interval_us = tcp_stamp_us_delta(tp->first_tx_mstamp,

						     scb->tx.first_tx_mstamp);



		/* Record send time of most recently ACKed packet: */

		tp->first_tx_mstamp  = skb->skb_mstamp;

	}

	/* Mark off the skb delivered once it's sacked to avoid being

	 * used again when it's cumulatively acked. For acked packets

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