// SPDX-License-Identifier: GPL-2.0-only /* * TCP Illinois congestion control. * Home page: * http://www.ews.uiuc.edu/~shaoliu/tcpillinois/index.html * * The algorithm is described in: * "TCP-Illinois: A Loss and Delay-Based Congestion Control Algorithm * for High-Speed Networks" * http://tamerbasar.csl.illinois.edu/LiuBasarSrikantPerfEvalArtJun2008.pdf * * Implemented from description in paper and ns-2 simulation. * Copyright (C) 2007 Stephen Hemminger <[email protected]> */ #include <linux/module.h> #include <linux/skbuff.h> #include <linux/inet_diag.h> #include <asm/div64.h> #include <net/tcp.h> #define ALPHA_SHIFT … #define ALPHA_SCALE … #define ALPHA_MIN … #define ALPHA_MAX … #define ALPHA_BASE … #define RTT_MAX … #define BETA_SHIFT … #define BETA_SCALE … #define BETA_MIN … #define BETA_MAX … #define BETA_BASE … static int win_thresh __read_mostly = …; module_param(win_thresh, int, 0); MODULE_PARM_DESC(…) …; static int theta __read_mostly = …; module_param(theta, int, 0); MODULE_PARM_DESC(…) …; /* TCP Illinois Parameters */ struct illinois { … }; static void rtt_reset(struct sock *sk) { … } static void tcp_illinois_init(struct sock *sk) { … } /* Measure RTT for each ack. */ static void tcp_illinois_acked(struct sock *sk, const struct ack_sample *sample) { … } /* Maximum queuing delay */ static inline u32 max_delay(const struct illinois *ca) { … } /* Average queuing delay */ static inline u32 avg_delay(const struct illinois *ca) { … } /* * Compute value of alpha used for additive increase. * If small window then use 1.0, equivalent to Reno. * * For larger windows, adjust based on average delay. * A. If average delay is at minimum (we are uncongested), * then use large alpha (10.0) to increase faster. * B. If average delay is at maximum (getting congested) * then use small alpha (0.3) * * The result is a convex window growth curve. */ static u32 alpha(struct illinois *ca, u32 da, u32 dm) { … } /* * Beta used for multiplicative decrease. * For small window sizes returns same value as Reno (0.5) * * If delay is small (10% of max) then beta = 1/8 * If delay is up to 80% of max then beta = 1/2 * In between is a linear function */ static u32 beta(u32 da, u32 dm) { … } /* Update alpha and beta values once per RTT */ static void update_params(struct sock *sk) { … } /* * In case of loss, reset to default values */ static void tcp_illinois_state(struct sock *sk, u8 new_state) { … } /* * Increase window in response to successful acknowledgment. */ static void tcp_illinois_cong_avoid(struct sock *sk, u32 ack, u32 acked) { … } static u32 tcp_illinois_ssthresh(struct sock *sk) { … } /* Extract info for Tcp socket info provided via netlink. */ static size_t tcp_illinois_info(struct sock *sk, u32 ext, int *attr, union tcp_cc_info *info) { … } static struct tcp_congestion_ops tcp_illinois __read_mostly = …; static int __init tcp_illinois_register(void) { … } static void __exit tcp_illinois_unregister(void) { … } module_init(…) …; module_exit(tcp_illinois_unregister); MODULE_AUTHOR(…) …; MODULE_LICENSE(…) …; MODULE_DESCRIPTION(…) …; MODULE_VERSION(…) …;
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