tcp: add earliest departure time to SCM_TIMESTAMPING_OPT_STATS

This change adds TCP_NLA_EDT to SCM_TIMESTAMPING_OPT_STATS that reports
the earliest departure time(EDT) of the timestamped skb. By tracking EDT
values of the skb from different timestamps, we can observe when and how
much the value changed. This allows to measure the precise delay
injected on the sender host e.g. by a bpf-base throttler.

Signed-off-by: Yousuk Seung <ysseung@google.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Neal Cardwell <ncardwell@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Acked-by: Yuchung Cheng <ycheng@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Yousuk Seung
2020-07-30 15:44:40 -07:00
committed by David S. Miller
parent c6886957d2
commit 48040793fa
4 changed files with 9 additions and 3 deletions

View File

@@ -4692,7 +4692,7 @@ void __skb_tstamp_tx(struct sk_buff *orig_skb,
if ((sk->sk_tsflags & SOF_TIMESTAMPING_OPT_STATS) &&
sk->sk_protocol == IPPROTO_TCP &&
sk->sk_type == SOCK_STREAM) {
skb = tcp_get_timestamping_opt_stats(sk);
skb = tcp_get_timestamping_opt_stats(sk, orig_skb);
opt_stats = true;
} else
#endif

View File

@@ -3501,10 +3501,12 @@ static size_t tcp_opt_stats_get_size(void)
nla_total_size(sizeof(u32)) + /* TCP_NLA_SRTT */
nla_total_size(sizeof(u16)) + /* TCP_NLA_TIMEOUT_REHASH */
nla_total_size(sizeof(u32)) + /* TCP_NLA_BYTES_NOTSENT */
nla_total_size_64bit(sizeof(u64)) + /* TCP_NLA_EDT */
0;
}
struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk)
struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk,
const struct sk_buff *orig_skb)
{
const struct tcp_sock *tp = tcp_sk(sk);
struct sk_buff *stats;
@@ -3558,6 +3560,8 @@ struct sk_buff *tcp_get_timestamping_opt_stats(const struct sock *sk)
nla_put_u16(stats, TCP_NLA_TIMEOUT_REHASH, tp->timeout_rehash);
nla_put_u32(stats, TCP_NLA_BYTES_NOTSENT,
max_t(int, 0, tp->write_seq - tp->snd_nxt));
nla_put_u64_64bit(stats, TCP_NLA_EDT, orig_skb->skb_mstamp_ns,
TCP_NLA_PAD);
return stats;
}