Orange Pi5 kernel

^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   1) // SPDX-License-Identifier: GPL-2.0-only
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   2) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   3)  * TCP Illinois congestion control.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   4)  * Home page:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   5)  *	http://www.ews.uiuc.edu/~shaoliu/tcpillinois/index.html
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   6)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   7)  * The algorithm is described in:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   8)  * "TCP-Illinois: A Loss and Delay-Based Congestion Control Algorithm
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300   9)  *  for High-Speed Networks"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  10)  * http://tamerbasar.csl.illinois.edu/LiuBasarSrikantPerfEvalArtJun2008.pdf
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  11)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  12)  * Implemented from description in paper and ns-2 simulation.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  13)  * Copyright (C) 2007 Stephen Hemminger <shemminger@linux-foundation.org>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  14)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  15) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  16) #include <linux/module.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  17) #include <linux/skbuff.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  18) #include <linux/inet_diag.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  19) #include <asm/div64.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  20) #include <net/tcp.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  21) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  22) #define ALPHA_SHIFT	7
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  23) #define ALPHA_SCALE	(1u<<ALPHA_SHIFT)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  24) #define ALPHA_MIN	((3*ALPHA_SCALE)/10)	/* ~0.3 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  25) #define ALPHA_MAX	(10*ALPHA_SCALE)	/* 10.0 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  26) #define ALPHA_BASE	ALPHA_SCALE		/* 1.0 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  27) #define RTT_MAX		(U32_MAX / ALPHA_MAX)	/* 3.3 secs */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  28) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  29) #define BETA_SHIFT	6
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  30) #define BETA_SCALE	(1u<<BETA_SHIFT)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  31) #define BETA_MIN	(BETA_SCALE/8)		/* 0.125 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  32) #define BETA_MAX	(BETA_SCALE/2)		/* 0.5 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  33) #define BETA_BASE	BETA_MAX
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  34) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  35) static int win_thresh __read_mostly = 15;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  36) module_param(win_thresh, int, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  37) MODULE_PARM_DESC(win_thresh, "Window threshold for starting adaptive sizing");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  38) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  39) static int theta __read_mostly = 5;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  40) module_param(theta, int, 0);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  41) MODULE_PARM_DESC(theta, "# of fast RTT's before full growth");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  42) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  43) /* TCP Illinois Parameters */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  44) struct illinois {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  45) 	u64	sum_rtt;	/* sum of rtt's measured within last rtt */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  46) 	u16	cnt_rtt;	/* # of rtts measured within last rtt */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  47) 	u32	base_rtt;	/* min of all rtt in usec */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  48) 	u32	max_rtt;	/* max of all rtt in usec */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  49) 	u32	end_seq;	/* right edge of current RTT */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  50) 	u32	alpha;		/* Additive increase */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  51) 	u32	beta;		/* Muliplicative decrease */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  52) 	u16	acked;		/* # packets acked by current ACK */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  53) 	u8	rtt_above;	/* average rtt has gone above threshold */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  54) 	u8	rtt_low;	/* # of rtts measurements below threshold */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  55) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  56) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  57) static void rtt_reset(struct sock *sk)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  58) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  59) 	struct tcp_sock *tp = tcp_sk(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  60) 	struct illinois *ca = inet_csk_ca(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  61) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  62) 	ca->end_seq = tp->snd_nxt;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  63) 	ca->cnt_rtt = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  64) 	ca->sum_rtt = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  65) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  66) 	/* TODO: age max_rtt? */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  67) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  68) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  69) static void tcp_illinois_init(struct sock *sk)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  70) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  71) 	struct illinois *ca = inet_csk_ca(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  72) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  73) 	ca->alpha = ALPHA_MAX;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  74) 	ca->beta = BETA_BASE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  75) 	ca->base_rtt = 0x7fffffff;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  76) 	ca->max_rtt = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  77) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  78) 	ca->acked = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  79) 	ca->rtt_low = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  80) 	ca->rtt_above = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  81) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  82) 	rtt_reset(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  83) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  84) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  85) /* Measure RTT for each ack. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  86) static void tcp_illinois_acked(struct sock *sk, const struct ack_sample *sample)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  87) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  88) 	struct illinois *ca = inet_csk_ca(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  89) 	s32 rtt_us = sample->rtt_us;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  90) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  91) 	ca->acked = sample->pkts_acked;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  92) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  93) 	/* dup ack, no rtt sample */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  94) 	if (rtt_us < 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  95) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  96) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  97) 	/* ignore bogus values, this prevents wraparound in alpha math */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  98) 	if (rtt_us > RTT_MAX)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300  99) 		rtt_us = RTT_MAX;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) 	/* keep track of minimum RTT seen so far */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) 	if (ca->base_rtt > rtt_us)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) 		ca->base_rtt = rtt_us;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) 	/* and max */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) 	if (ca->max_rtt < rtt_us)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107) 		ca->max_rtt = rtt_us;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) 	++ca->cnt_rtt;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) 	ca->sum_rtt += rtt_us;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 111) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 112) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 113) /* Maximum queuing delay */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) static inline u32 max_delay(const struct illinois *ca)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) 	return ca->max_rtt - ca->base_rtt;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) /* Average queuing delay */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) static inline u32 avg_delay(const struct illinois *ca)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) 	u64 t = ca->sum_rtt;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) 	do_div(t, ca->cnt_rtt);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) 	return t - ca->base_rtt;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129)  * Compute value of alpha used for additive increase.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130)  * If small window then use 1.0, equivalent to Reno.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132)  * For larger windows, adjust based on average delay.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133)  * A. If average delay is at minimum (we are uncongested),
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134)  *    then use large alpha (10.0) to increase faster.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135)  * B. If average delay is at maximum (getting congested)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136)  *    then use small alpha (0.3)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138)  * The result is a convex window growth curve.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) static u32 alpha(struct illinois *ca, u32 da, u32 dm)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142) 	u32 d1 = dm / 100;	/* Low threshold */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) 	if (da <= d1) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) 		/* If never got out of low delay zone, then use max */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) 		if (!ca->rtt_above)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147) 			return ALPHA_MAX;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) 		/* Wait for 5 good RTT's before allowing alpha to go alpha max.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) 		 * This prevents one good RTT from causing sudden window increase.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) 		 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) 		if (++ca->rtt_low < theta)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) 			return ca->alpha;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) 		ca->rtt_low = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156) 		ca->rtt_above = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) 		return ALPHA_MAX;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) 	ca->rtt_above = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) 	 * Based on:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) 	 *      (dm - d1) amin amax
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) 	 * k1 = -------------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167) 	 *         amax - amin
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169) 	 *       (dm - d1) amin
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) 	 * k2 = ----------------  - d1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) 	 *        amax - amin
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) 	 *             k1
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174) 	 * alpha = ----------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) 	 *          k2 + da
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) 	dm -= d1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) 	da -= d1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) 	return (dm * ALPHA_MAX) /
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) 		(dm + (da  * (ALPHA_MAX - ALPHA_MIN)) / ALPHA_MIN);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185)  * Beta used for multiplicative decrease.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186)  * For small window sizes returns same value as Reno (0.5)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187)  *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188)  * If delay is small (10% of max) then beta = 1/8
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189)  * If delay is up to 80% of max then beta = 1/2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190)  * In between is a linear function
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) static u32 beta(u32 da, u32 dm)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194) 	u32 d2, d3;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) 	d2 = dm / 10;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) 	if (da <= d2)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) 		return BETA_MIN;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) 	d3 = (8 * dm) / 10;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) 	if (da >= d3 || d3 <= d2)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) 		return BETA_MAX;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 203) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 204) 	/*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 205) 	 * Based on:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207) 	 *       bmin d3 - bmax d2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) 	 * k3 = -------------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) 	 *         d3 - d2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) 	 *       bmax - bmin
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) 	 * k4 = -------------
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) 	 *         d3 - d2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) 	 *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) 	 * b = k3 + k4 da
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) 	 */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) 	return (BETA_MIN * d3 - BETA_MAX * d2 + (BETA_MAX - BETA_MIN) * da)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) 		/ (d3 - d2);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221) /* Update alpha and beta values once per RTT */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) static void update_params(struct sock *sk)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224) 	struct tcp_sock *tp = tcp_sk(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) 	struct illinois *ca = inet_csk_ca(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) 	if (tp->snd_cwnd < win_thresh) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) 		ca->alpha = ALPHA_BASE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229) 		ca->beta = BETA_BASE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) 	} else if (ca->cnt_rtt > 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) 		u32 dm = max_delay(ca);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232) 		u32 da = avg_delay(ca);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) 		ca->alpha = alpha(ca, da, dm);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) 		ca->beta = beta(da, dm);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) 	rtt_reset(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242)  * In case of loss, reset to default values
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244) static void tcp_illinois_state(struct sock *sk, u8 new_state)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) 	struct illinois *ca = inet_csk_ca(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) 	if (new_state == TCP_CA_Loss) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) 		ca->alpha = ALPHA_BASE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) 		ca->beta = BETA_BASE;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) 		ca->rtt_low = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) 		ca->rtt_above = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) 		rtt_reset(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258)  * Increase window in response to successful acknowledgment.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259)  */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) static void tcp_illinois_cong_avoid(struct sock *sk, u32 ack, u32 acked)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) 	struct tcp_sock *tp = tcp_sk(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) 	struct illinois *ca = inet_csk_ca(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265) 	if (after(ack, ca->end_seq))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) 		update_params(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) 	/* RFC2861 only increase cwnd if fully utilized */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) 	if (!tcp_is_cwnd_limited(sk))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) 		return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) 	/* In slow start */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) 	if (tcp_in_slow_start(tp))
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) 		tcp_slow_start(tp, acked);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) 	else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277) 		u32 delta;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) 		/* snd_cwnd_cnt is # of packets since last cwnd increment */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) 		tp->snd_cwnd_cnt += ca->acked;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) 		ca->acked = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) 		/* This is close approximation of:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) 		 * tp->snd_cwnd += alpha/tp->snd_cwnd
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) 		*/
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) 		delta = (tp->snd_cwnd_cnt * ca->alpha) >> ALPHA_SHIFT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287) 		if (delta >= tp->snd_cwnd) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) 			tp->snd_cwnd = min(tp->snd_cwnd + delta / tp->snd_cwnd,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) 					   (u32)tp->snd_cwnd_clamp);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) 			tp->snd_cwnd_cnt = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) static u32 tcp_illinois_ssthresh(struct sock *sk)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297) 	struct tcp_sock *tp = tcp_sk(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) 	struct illinois *ca = inet_csk_ca(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) 	/* Multiplicative decrease */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) 	return max(tp->snd_cwnd - ((tp->snd_cwnd * ca->beta) >> BETA_SHIFT), 2U);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) /* Extract info for Tcp socket info provided via netlink. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305) static size_t tcp_illinois_info(struct sock *sk, u32 ext, int *attr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) 				union tcp_cc_info *info)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) 	const struct illinois *ca = inet_csk_ca(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 309) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 310) 	if (ext & (1 << (INET_DIAG_VEGASINFO - 1))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 311) 		info->vegas.tcpv_enabled = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 312) 		info->vegas.tcpv_rttcnt = ca->cnt_rtt;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 313) 		info->vegas.tcpv_minrtt = ca->base_rtt;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 314) 		info->vegas.tcpv_rtt = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 315) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 316) 		if (info->vegas.tcpv_rttcnt > 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 317) 			u64 t = ca->sum_rtt;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 318) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 319) 			do_div(t, info->vegas.tcpv_rttcnt);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 320) 			info->vegas.tcpv_rtt = t;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 321) 		}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 322) 		*attr = INET_DIAG_VEGASINFO;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 323) 		return sizeof(struct tcpvegas_info);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 324) 	}
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 325) 	return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 326) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 327) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 328) static struct tcp_congestion_ops tcp_illinois __read_mostly = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 329) 	.init		= tcp_illinois_init,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 330) 	.ssthresh	= tcp_illinois_ssthresh,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 331) 	.undo_cwnd	= tcp_reno_undo_cwnd,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 332) 	.cong_avoid	= tcp_illinois_cong_avoid,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 333) 	.set_state	= tcp_illinois_state,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 334) 	.get_info	= tcp_illinois_info,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 335) 	.pkts_acked	= tcp_illinois_acked,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 336) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 337) 	.owner		= THIS_MODULE,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 338) 	.name		= "illinois",
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 339) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 340) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 341) static int __init tcp_illinois_register(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 342) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 343) 	BUILD_BUG_ON(sizeof(struct illinois) > ICSK_CA_PRIV_SIZE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 344) 	return tcp_register_congestion_control(&tcp_illinois);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 345) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 346) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 347) static void __exit tcp_illinois_unregister(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 348) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 349) 	tcp_unregister_congestion_control(&tcp_illinois);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 350) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 351) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 352) module_init(tcp_illinois_register);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 353) module_exit(tcp_illinois_unregister);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 354) 
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 355) MODULE_AUTHOR("Stephen Hemminger, Shao Liu");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 356) MODULE_LICENSE("GPL");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 357) MODULE_DESCRIPTION("TCP Illinois");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 358) MODULE_VERSION("1.0");