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Commit 712a7221 authored by Willem de Bruijn's avatar Willem de Bruijn Committed by David S. Miller
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net-timestamp: fix missing ACK timestamp 



ACK timestamps are generated in tcp_clean_rtx_queue. The TSO datapath
can break out early, causing the timestamp code to be skipped. Move
the code up before the break.

Reported-by: default avatarDavid S. Miller <davem@davemloft.net>

Also fix a boundary condition: tp->snd_una is the next unacknowledged
byte and between tests inclusive (a <= b <= c), so generate a an ACK
timestamp if (prior_snd_una <= tskey <= tp->snd_una - 1).

Signed-off-by: default avatarWillem de Bruijn <willemb@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent cd094927

net/ipv4/tcp_input.c

+5 −5
Original line number Diff line number Diff line
@@ -3050,10 +3050,15 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets, 
	first_ackt.v64 = 0;



	while ((skb = tcp_write_queue_head(sk)) && skb != tcp_send_head(sk)) {

		struct skb_shared_info *shinfo = skb_shinfo(skb);

		struct tcp_skb_cb *scb = TCP_SKB_CB(skb);

		u8 sacked = scb->sacked;

		u32 acked_pcount;



		if (unlikely(shinfo->tx_flags & SKBTX_ACK_TSTAMP) &&

		    between(shinfo->tskey, prior_snd_una, tp->snd_una - 1))

			__skb_tstamp_tx(skb, NULL, sk, SCM_TSTAMP_ACK);



		/* Determine how many packets and what bytes were acked, tso and else */

		if (after(scb->end_seq, tp->snd_una)) {

			if (tcp_skb_pcount(skb) == 1 ||
@@ -3107,11 +3112,6 @@ static int tcp_clean_rtx_queue(struct sock *sk, int prior_fackets, 
			tp->retrans_stamp = 0;

		}



		if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_ACK_TSTAMP) &&

		    between(skb_shinfo(skb)->tskey, prior_snd_una,

			    tp->snd_una + 1))

			__skb_tstamp_tx(skb, NULL, sk, SCM_TSTAMP_ACK);



		if (!fully_acked)

			break;