Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit b103cf34 authored by Julian Anastasov's avatar Julian Anastasov Committed by David S. Miller
Browse files

tcp: fix TCP_DEFER_ACCEPT retrans calculation 



Fix TCP_DEFER_ACCEPT conversion between seconds and
retransmission to match the TCP SYN-ACK retransmission periods
because the time is converted to such retransmissions. The old
algorithm selects one more retransmission in some cases. Allow
up to 255 retransmissions.

Signed-off-by: default avatarJulian Anastasov <ja@ssi.bg>
Acked-by: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0c3d79bc

net/ipv4/tcp.c

+43 −12
Original line number Diff line number Diff line
@@ -326,6 +326,43 @@ void tcp_enter_memory_pressure(struct sock *sk) 


EXPORT_SYMBOL(tcp_enter_memory_pressure);



/* Convert seconds to retransmits based on initial and max timeout */

static u8 secs_to_retrans(int seconds, int timeout, int rto_max)

{

	u8 res = 0;



	if (seconds > 0) {

		int period = timeout;



		res = 1;

		while (seconds > period && res < 255) {

			res++;

			timeout <<= 1;

			if (timeout > rto_max)

				timeout = rto_max;

			period += timeout;

		}

	}

	return res;

}



/* Convert retransmits to seconds based on initial and max timeout */

static int retrans_to_secs(u8 retrans, int timeout, int rto_max)

{

	int period = 0;



	if (retrans > 0) {

		period = timeout;

		while (--retrans) {

			timeout <<= 1;

			if (timeout > rto_max)

				timeout = rto_max;

			period += timeout;

		}

	}

	return period;

}



/*

 *	Wait for a TCP event.

 *
@@ -2163,16 +2200,10 @@ static int do_tcp_setsockopt(struct sock *sk, int level, 
		break;



	case TCP_DEFER_ACCEPT:

		icsk->icsk_accept_queue.rskq_defer_accept = 0;

		if (val > 0) {

			/* Translate value in seconds to number of

			 * retransmits */

			while (icsk->icsk_accept_queue.rskq_defer_accept < 32 &&

			       val > ((TCP_TIMEOUT_INIT / HZ) <<

				       icsk->icsk_accept_queue.rskq_defer_accept))

				icsk->icsk_accept_queue.rskq_defer_accept++;

			icsk->icsk_accept_queue.rskq_defer_accept++;

		}

		/* Translate value in seconds to number of retransmits */

		icsk->icsk_accept_queue.rskq_defer_accept =

			secs_to_retrans(val, TCP_TIMEOUT_INIT / HZ,

					TCP_RTO_MAX / HZ);

		break;



	case TCP_WINDOW_CLAMP:
@@ -2353,8 +2384,8 @@ static int do_tcp_getsockopt(struct sock *sk, int level, 
			val = (val ? : sysctl_tcp_fin_timeout) / HZ;

		break;

	case TCP_DEFER_ACCEPT:

		val = !icsk->icsk_accept_queue.rskq_defer_accept ? 0 :

			((TCP_TIMEOUT_INIT / HZ) << (icsk->icsk_accept_queue.rskq_defer_accept - 1));

		val = retrans_to_secs(icsk->icsk_accept_queue.rskq_defer_accept,

				      TCP_TIMEOUT_INIT / HZ, TCP_RTO_MAX / HZ);

		break;

	case TCP_WINDOW_CLAMP:

		val = tp->window_clamp;