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fix tcp keepalive maxidle calculation
On Wed, Sep 17, 2025 at 12:41:53AM +0200, Alexander Bluhm wrote:
> On Fri, Sep 12, 2025 at 12:25:46AM +0200, Alexander Bluhm wrote:
> > Hi,
> >
> > Here I messed up TCP keepalive variables keepidle and keepintvl.
> >
> > ----------------------------
> > revision 1.82
> > date: 2025/01/16 11:59:20; author: bluhm; state: Exp; lines: +17 -39; commit
> > id: FhSoryD8VCfunQNr;
> > Remove net lock from TCP sysctl for keep alive.
> >
> > Keep copies in seconds for the sysctl and update timer variables
> > atomically when they change. tcp_maxidle was historically calculated
> > in tcp_slowtimo() as the timers were called from there. Better
> > calculate maxidle when needed. tcp_timer_init() is useless, just
> > initialize data. While there make the names consistent.
> >
> > input sthen@; OK mvs@
> > ----------------------------
> >
> > Restore original behavior.
> >
> > ok?
>
> Anyone?
>
ok mvs
> bluhm
>
> Index: netinet/tcp_timer.c
> ===================================================================
> RCS file: /data/mirror/openbsd/cvs/src/sys/netinet/tcp_timer.c,v
> diff -u -p -r1.87 tcp_timer.c
> --- netinet/tcp_timer.c 8 Jul 2025 00:47:41 -0000 1.87
> +++ netinet/tcp_timer.c 16 Sep 2025 22:27:49 -0000
> @@ -472,11 +472,12 @@ tcp_timer_keep(void *arg)
> if ((atomic_load_int(&tcp_always_keepalive) ||
> so->so_options & SO_KEEPALIVE) &&
> tp->t_state <= TCPS_CLOSING) {
> - int keepidle, maxidle;
> + int keepidle, keepintvl, maxidle;
> uint64_t now;
>
> keepidle = atomic_load_int(&tcp_keepidle);
> - maxidle = TCPTV_KEEPCNT * keepidle;
> + keepintvl = atomic_load_int(&tcp_keepintvl);
> + maxidle = TCPTV_KEEPCNT * keepintvl;
> now = tcp_now();
> if ((maxidle > 0) &&
> ((now - tp->t_rcvtime) >= keepidle + maxidle)) {
> @@ -499,7 +500,7 @@ tcp_timer_keep(void *arg)
> tcpstat_inc(tcps_keepprobe);
> tcp_respond(tp, mtod(tp->t_template, caddr_t),
> NULL, tp->rcv_nxt, tp->snd_una - 1, 0, 0, now);
> - TCP_TIMER_ARM(tp, TCPT_KEEP, atomic_load_int(&tcp_keepintvl));
> + TCP_TIMER_ARM(tp, TCPT_KEEP, keepintvl);
> } else
> TCP_TIMER_ARM(tp, TCPT_KEEP, atomic_load_int(&tcp_keepidle));
> if (otp)
> @@ -516,7 +517,7 @@ tcp_timer_2msl(void *arg)
> struct tcpcb *otp = NULL, *tp;
> short ostate;
> uint64_t now;
> - int maxidle;
> + int keepintvl, maxidle;
>
> if (tcp_timer_enter(inp, &so, &tp, TCPT_2MSL))
> goto out;
> @@ -527,11 +528,12 @@ tcp_timer_2msl(void *arg)
> }
> tcp_timer_freesack(tp);
>
> - maxidle = TCPTV_KEEPCNT * atomic_load_int(&tcp_keepidle);
> + keepintvl = atomic_load_int(&tcp_keepintvl);
> + maxidle = TCPTV_KEEPCNT * keepintvl;
> now = tcp_now();
> if (tp->t_state != TCPS_TIME_WAIT &&
> ((maxidle == 0) || ((now - tp->t_rcvtime) <= maxidle)))
> - TCP_TIMER_ARM(tp, TCPT_2MSL, atomic_load_int(&tcp_keepintvl));
> + TCP_TIMER_ARM(tp, TCPT_2MSL, keepintvl);
> else
> tp = tcp_close(tp);
> if (otp)
>
fix tcp keepalive maxidle calculation