On Mon, Apr 18, 2016 at 6:46 PM, Martin KaFai Lau <ka...@fb.com> wrote: > When a tcp skb is sliced into two smaller skbs (e.g. in > tcp_fragment() and tso_fragment()), it does not carry > the txstamp_ack bit to the newly created skb if it is needed. > The end result is a timestamping event (SCM_TSTAMP_ACK) will > be missing from the sk->sk_error_queue. > > This patch carries this bit to the new skb2 (if needed) > in tcp_fragment_tstamp(). > > BPF Output Before: > ~~~~~~ > <No output due to missing SCM_TSTAMP_ACK timestamp> > > BPF Output After: > ~~~~~~ > <...>-2050 [000] d.s. 100.928763: : ee_data:14599 > > Packetdrill Script: > ~~~~~~ > +0 `sysctl -q -w net.ipv4.tcp_min_tso_segs=10` > +0 `sysctl -q -w net.ipv4.tcp_no_metrics_save=1` > +0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3 > +0 setsockopt(3, SOL_SOCKET, SO_REUSEADDR, [1], 4) = 0 > +0 bind(3, ..., ...) = 0 > +0 listen(3, 1) = 0 > > 0.100 < S 0:0(0) win 32792 <mss 1460,sackOK,nop,nop,nop,wscale 7> > 0.100 > S. 0:0(0) ack 1 <mss 1460,nop,nop,sackOK,nop,wscale 7> > 0.200 < . 1:1(0) ack 1 win 257 > 0.200 accept(3, ..., ...) = 4 > +0 setsockopt(4, SOL_TCP, TCP_NODELAY, [1], 4) = 0 > > +0 setsockopt(4, SOL_SOCKET, 37, [2688], 4) = 0 > 0.200 write(4, ..., 14600) = 14600 > +0 setsockopt(4, SOL_SOCKET, 37, [2176], 4) = 0 > > 0.200 > . 1:7301(7300) ack 1 > 0.200 > P. 7301:14601(7300) ack 1 > > 0.300 < . 1:1(0) ack 14601 win 257 > > 0.300 close(4) = 0 > 0.300 > F. 14601:14601(0) ack 1 > 0.400 < F. 1:1(0) ack 16062 win 257 > 0.400 > . 14602:14602(0) ack 2 > > Signed-off-by: Martin KaFai Lau <ka...@fb.com> > Cc: Eric Dumazet <eduma...@google.com> > Cc: Neal Cardwell <ncardw...@google.com> > Cc: Soheil Hassas Yeganeh <soheil.k...@gmail.com> Cc: Soheil Hassas Yeganeh <soh...@google.com> Acked-by: Soheil Hassas Yeganeh <soh...@google.com>
> Cc: Willem de Bruijn <will...@google.com> > Cc: Yuchung Cheng <ych...@google.com> > --- > net/ipv4/tcp_output.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c > index 6451b83..0527ce9 100644 > --- a/net/ipv4/tcp_output.c > +++ b/net/ipv4/tcp_output.c > @@ -1123,6 +1123,8 @@ static void tcp_fragment_tstamp(struct sk_buff *skb, > struct sk_buff *skb2) > shinfo->tx_flags &= ~tsflags; > shinfo2->tx_flags |= tsflags; > swap(shinfo->tskey, shinfo2->tskey); > + TCP_SKB_CB(skb2)->txstamp_ack = TCP_SKB_CB(skb)->txstamp_ack; > + TCP_SKB_CB(skb)->txstamp_ack = 0; > } > } Thanks for the fixes! I was going to submit similar patches. :-) Could you please submit the timestamping patches separately as non RFCs? Thanks! > -- > 2.5.1 >
