diff options
| author | David S. Miller <davem@davemloft.net> | 2023-10-23 09:35:02 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2023-10-23 09:35:02 +0100 |
| commit | bdf24b4bdfa59b124f9d0ff837f8d35a908da3b8 (patch) | |
| tree | be82eb8c966ea4a7efa7cd6ed0df9d8968ed9f5d /net/ipv4/tcp_minisocks.c | |
| parent | 35c1b273206346c4178928b1121675dc143e61d2 (diff) | |
| parent | a77a0f5c7f23a8a4981a2a3ff47baa91ceaf1f53 (diff) | |
Merge branch 'tcp-ts-usec-resolution'
Eric Dumazet says:
====================
tcp: add optional usec resolution to TCP TS
As discussed in various public places in 2016, Google adopted
usec resolution in RFC 7323 TS values, at Van Jacobson suggestion.
Goals were :
1) better observability of delays in networking stacks/fabrics.
2) better disambiguation of events based on TSval/ecr values.
3) building block for congestion control modules needing usec resolution.
Back then we implemented a schem based on private SYN options
to safely negotiate the feature.
For upstream submission, we chose to use a much simpler route
attribute because this feature is probably going to be used
in private networks.
ip route add 10/8 ... features tcp_usec_ts
References:
https://www.ietf.org/proceedings/97/slides/slides-97-tcpm-tcp-options-for-low-latency-00.pdf
https://datatracker.ietf.org/doc/draft-wang-tcpm-low-latency-opt/
First two patches are fixing old minor bugs and might be taken
by stable teams (thanks to appropriate Fixes: tags)
====================
Acked-by: Neal Cardwell <ncardwell@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/tcp_minisocks.c')
| -rw-r--r-- | net/ipv4/tcp_minisocks.c | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/net/ipv4/tcp_minisocks.c b/net/ipv4/tcp_minisocks.c index 3f87611077ef..ace806c5bd0c 100644 --- a/net/ipv4/tcp_minisocks.c +++ b/net/ipv4/tcp_minisocks.c @@ -300,6 +300,7 @@ void tcp_time_wait(struct sock *sk, int state, int timeo) tcptw->tw_ts_recent = tp->rx_opt.ts_recent; tcptw->tw_ts_recent_stamp = tp->rx_opt.ts_recent_stamp; tcptw->tw_ts_offset = tp->tsoffset; + tw->tw_usec_ts = tp->tcp_usec_ts; tcptw->tw_last_oow_ack_time = 0; tcptw->tw_tx_delay = tp->tcp_tx_delay; tw->tw_txhash = sk->sk_txhash; @@ -554,21 +555,29 @@ struct sock *tcp_create_openreq_child(const struct sock *sk, newtp->max_window = newtp->snd_wnd; if (newtp->rx_opt.tstamp_ok) { + newtp->tcp_usec_ts = treq->req_usec_ts; newtp->rx_opt.ts_recent = READ_ONCE(req->ts_recent); newtp->rx_opt.ts_recent_stamp = ktime_get_seconds(); newtp->tcp_header_len = sizeof(struct tcphdr) + TCPOLEN_TSTAMP_ALIGNED; } else { + newtp->tcp_usec_ts = 0; newtp->rx_opt.ts_recent_stamp = 0; newtp->tcp_header_len = sizeof(struct tcphdr); } if (req->num_timeout) { - newtp->undo_marker = treq->snt_isn; - newtp->retrans_stamp = div_u64(treq->snt_synack, - USEC_PER_SEC / TCP_TS_HZ); newtp->total_rto = req->num_timeout; - newtp->total_rto_recoveries = 1; - newtp->total_rto_time = tcp_time_stamp_raw() - + newtp->undo_marker = treq->snt_isn; + if (newtp->tcp_usec_ts) { + newtp->retrans_stamp = treq->snt_synack; + newtp->total_rto_time = (u32)(tcp_clock_us() - + newtp->retrans_stamp) / USEC_PER_MSEC; + } else { + newtp->retrans_stamp = div_u64(treq->snt_synack, + USEC_PER_SEC / TCP_TS_HZ); + newtp->total_rto_time = tcp_clock_ms() - newtp->retrans_stamp; + } + newtp->total_rto_recoveries = 1; } newtp->tsoffset = treq->ts_off; #ifdef CONFIG_TCP_MD5SIG |