Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 194 insertions, 0 deletions

diff --git a/net/ipv4/tcp_hybla.c b/net/ipv4/tcp_hybla.c
new file mode 100644
index 000000000..abd7d9180
--- /dev/null
+++ b/net/ipv4/tcp_hybla.c
@@ -0,0 +1,194 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * TCP HYBLA
+ *
+ * TCP-HYBLA Congestion control algorithm, based on:
+ *   C.Caini, R.Firrincieli, "TCP-Hybla: A TCP Enhancement
+ *   for Heterogeneous Networks",
+ *   International Journal on satellite Communications,
+ *				       September 2004
+ *    Daniele Lacamera
+ *    root at danielinux.net
+ */
+
+#include <linux/module.h>
+#include <net/tcp.h>
+
+/* Tcp Hybla structure. */
+struct hybla {
+	bool  hybla_en;
+	u32   snd_cwnd_cents; /* Keeps increment values when it is <1, <<7 */
+	u32   rho;	      /* Rho parameter, integer part  */
+	u32   rho2;	      /* Rho * Rho, integer part */
+	u32   rho_3ls;	      /* Rho parameter, <<3 */
+	u32   rho2_7ls;	      /* Rho^2, <<7	*/
+	u32   minrtt_us;      /* Minimum smoothed round trip time value seen */
+};
+
+/* Hybla reference round trip time (default= 1/40 sec = 25 ms), in ms */
+static int rtt0 = 25;
+module_param(rtt0, int, 0644);
+MODULE_PARM_DESC(rtt0, "reference rout trip time (ms)");
+
+/* This is called to refresh values for hybla parameters */
+static inline void hybla_recalc_param (struct sock *sk)
+{
+	struct hybla *ca = inet_csk_ca(sk);
+
+	ca->rho_3ls = max_t(u32,
+			    tcp_sk(sk)->srtt_us / (rtt0 * USEC_PER_MSEC),
+			    8U);
+	ca->rho = ca->rho_3ls >> 3;
+	ca->rho2_7ls = (ca->rho_3ls * ca->rho_3ls) << 1;
+	ca->rho2 = ca->rho2_7ls >> 7;
+}
+
+static void hybla_init(struct sock *sk)
+{
+	struct tcp_sock *tp = tcp_sk(sk);
+	struct hybla *ca = inet_csk_ca(sk);
+
+	ca->rho = 0;
+	ca->rho2 = 0;
+	ca->rho_3ls = 0;
+	ca->rho2_7ls = 0;
+	ca->snd_cwnd_cents = 0;
+	ca->hybla_en = true;
+	tcp_snd_cwnd_set(tp, 2);
+	tp->snd_cwnd_clamp = 65535;
+
+	/* 1st Rho measurement based on initial srtt */
+	hybla_recalc_param(sk);
+
+	/* set minimum rtt as this is the 1st ever seen */
+	ca->minrtt_us = tp->srtt_us;
+	tcp_snd_cwnd_set(tp, ca->rho);
+}
+
+static void hybla_state(struct sock *sk, u8 ca_state)
+{
+	struct hybla *ca = inet_csk_ca(sk);
+
+	ca->hybla_en = (ca_state == TCP_CA_Open);
+}
+
+static inline u32 hybla_fraction(u32 odds)
+{
+	static const u32 fractions[] = {
+		128, 139, 152, 165, 181, 197, 215, 234,
+	};
+
+	return (odds < ARRAY_SIZE(fractions)) ? fractions[odds] : 128;
+}
+
+/* TCP Hybla main routine.
+ * This is the algorithm behavior:
+ *     o Recalc Hybla parameters if min_rtt has changed
+ *     o Give cwnd a new value based on the model proposed
+ *     o remember increments <1
+ */
+static void hybla_cong_avoid(struct sock *sk, u32 ack, u32 acked)
+{
+	struct tcp_sock *tp = tcp_sk(sk);
+	struct hybla *ca = inet_csk_ca(sk);
+	u32 increment, odd, rho_fractions;
+	int is_slowstart = 0;
+
+	/*  Recalculate rho only if this srtt is the lowest */
+	if (tp->srtt_us < ca->minrtt_us) {
+		hybla_recalc_param(sk);
+		ca->minrtt_us = tp->srtt_us;
+	}
+
+	if (!tcp_is_cwnd_limited(sk))
+		return;
+
+	if (!ca->hybla_en) {
+		tcp_reno_cong_avoid(sk, ack, acked);
+		return;
+	}
+
+	if (ca->rho == 0)
+		hybla_recalc_param(sk);
+
+	rho_fractions = ca->rho_3ls - (ca->rho << 3);
+
+	if (tcp_in_slow_start(tp)) {
+		/*
+		 * slow start
+		 *      INC = 2^RHO - 1
+		 * This is done by splitting the rho parameter
+		 * into 2 parts: an integer part and a fraction part.
+		 * Inrement<<7 is estimated by doing:
+		 *	       [2^(int+fract)]<<7
+		 * that is equal to:
+		 *	       (2^int)	*  [(2^fract) <<7]
+		 * 2^int is straightly computed as 1<<int,
+		 * while we will use hybla_slowstart_fraction_increment() to
+		 * calculate 2^fract in a <<7 value.
+		 */
+		is_slowstart = 1;
+		increment = ((1 << min(ca->rho, 16U)) *
+			hybla_fraction(rho_fractions)) - 128;
+	} else {
+		/*
+		 * congestion avoidance
+		 * INC = RHO^2 / W
+		 * as long as increment is estimated as (rho<<7)/window
+		 * it already is <<7 and we can easily count its fractions.
+		 */
+		increment = ca->rho2_7ls / tcp_snd_cwnd(tp);
+		if (increment < 128)
+			tp->snd_cwnd_cnt++;
+	}
+
+	odd = increment % 128;
+	tcp_snd_cwnd_set(tp, tcp_snd_cwnd(tp) + (increment >> 7));
+	ca->snd_cwnd_cents += odd;
+
+	/* check when fractions goes >=128 and increase cwnd by 1. */
+	while (ca->snd_cwnd_cents >= 128) {
+		tcp_snd_cwnd_set(tp, tcp_snd_cwnd(tp) + 1);
+		ca->snd_cwnd_cents -= 128;
+		tp->snd_cwnd_cnt = 0;
+	}
+	/* check when cwnd has not been incremented for a while */
+	if (increment == 0 && odd == 0 && tp->snd_cwnd_cnt >= tcp_snd_cwnd(tp)) {
+		tcp_snd_cwnd_set(tp, tcp_snd_cwnd(tp) + 1);
+		tp->snd_cwnd_cnt = 0;
+	}
+	/* clamp down slowstart cwnd to ssthresh value. */
+	if (is_slowstart)
+		tcp_snd_cwnd_set(tp, min(tcp_snd_cwnd(tp), tp->snd_ssthresh));
+
+	tcp_snd_cwnd_set(tp, min(tcp_snd_cwnd(tp), tp->snd_cwnd_clamp));
+}
+
+static struct tcp_congestion_ops tcp_hybla __read_mostly = {
+	.init		= hybla_init,
+	.ssthresh	= tcp_reno_ssthresh,
+	.undo_cwnd	= tcp_reno_undo_cwnd,
+	.cong_avoid	= hybla_cong_avoid,
+	.set_state	= hybla_state,
+
+	.owner		= THIS_MODULE,
+	.name		= "hybla"
+};
+
+static int __init hybla_register(void)
+{
+	BUILD_BUG_ON(sizeof(struct hybla) > ICSK_CA_PRIV_SIZE);
+	return tcp_register_congestion_control(&tcp_hybla);
+}
+
+static void __exit hybla_unregister(void)
+{
+	tcp_unregister_congestion_control(&tcp_hybla);
+}
+
+module_init(hybla_register);
+module_exit(hybla_unregister);
+
+MODULE_AUTHOR("Daniele Lacamera");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("TCP Hybla");