^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 Westwood+: end-to-end bandwidth estimation for TCP
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 4) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 5) * Angelo Dell'Aera: author of the first version of TCP Westwood+ in Linux 2.4
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 6) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 7) * Support at http://c3lab.poliba.it/index.php/Westwood
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 8) * Main references in literature:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 9) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 10) * - Mascolo S, Casetti, M. Gerla et al.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 11) * "TCP Westwood: bandwidth estimation for TCP" Proc. ACM Mobicom 2001
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 12) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 13) * - A. Grieco, s. Mascolo
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 14) * "Performance evaluation of New Reno, Vegas, Westwood+ TCP" ACM Computer
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 15) * Comm. Review, 2004
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 16) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 17) * - A. Dell'Aera, L. Grieco, S. Mascolo.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 18) * "Linux 2.4 Implementation of Westwood+ TCP with Rate-Halving :
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 19) * A Performance Evaluation Over the Internet" (ICC 2004), Paris, June 2004
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 20) *
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 21) * Westwood+ employs end-to-end bandwidth measurement to set cwnd and
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 22) * ssthresh after packet loss. The probing phase is as the original Reno.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 23) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 24)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 25) #include <linux/mm.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 26) #include <linux/module.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 27) #include <linux/skbuff.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 28) #include <linux/inet_diag.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 29) #include <net/tcp.h>
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 30)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 31) /* TCP Westwood structure */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 32) struct westwood {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 33) u32 bw_ns_est; /* first bandwidth estimation..not too smoothed 8) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 34) u32 bw_est; /* bandwidth estimate */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 35) u32 rtt_win_sx; /* here starts a new evaluation... */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 36) u32 bk;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 37) u32 snd_una; /* used for evaluating the number of acked bytes */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 38) u32 cumul_ack;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 39) u32 accounted;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 40) u32 rtt;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 41) u32 rtt_min; /* minimum observed RTT */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 42) u8 first_ack; /* flag which infers that this is the first ack */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 43) u8 reset_rtt_min; /* Reset RTT min to next RTT sample*/
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 44) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 45)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 46) /* TCP Westwood functions and constants */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 47) #define TCP_WESTWOOD_RTT_MIN (HZ/20) /* 50ms */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 48) #define TCP_WESTWOOD_INIT_RTT (20*HZ) /* maybe too conservative?! */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 49)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 50) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 51) * @tcp_westwood_create
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 52) * This function initializes fields used in TCP Westwood+,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 53) * it is called after the initial SYN, so the sequence numbers
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 54) * are correct but new passive connections we have no
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 55) * information about RTTmin at this time so we simply set it to
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 56) * TCP_WESTWOOD_INIT_RTT. This value was chosen to be too conservative
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 57) * since in this way we're sure it will be updated in a consistent
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 58) * way as soon as possible. It will reasonably happen within the first
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 59) * RTT period of the connection lifetime.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 60) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 61) static void tcp_westwood_init(struct sock *sk)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 62) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 63) struct westwood *w = inet_csk_ca(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 64)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 65) w->bk = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 66) w->bw_ns_est = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 67) w->bw_est = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 68) w->accounted = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 69) w->cumul_ack = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 70) w->reset_rtt_min = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 71) w->rtt_min = w->rtt = TCP_WESTWOOD_INIT_RTT;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 72) w->rtt_win_sx = tcp_jiffies32;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 73) w->snd_una = tcp_sk(sk)->snd_una;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 74) w->first_ack = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 75) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 76)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 77) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 78) * @westwood_do_filter
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 79) * Low-pass filter. Implemented using constant coefficients.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 80) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 81) static inline u32 westwood_do_filter(u32 a, u32 b)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 82) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 83) return ((7 * a) + b) >> 3;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 84) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 85)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 86) static void westwood_filter(struct westwood *w, u32 delta)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 87) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 88) /* If the filter is empty fill it with the first sample of bandwidth */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 89) if (w->bw_ns_est == 0 && w->bw_est == 0) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 90) w->bw_ns_est = w->bk / delta;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 91) w->bw_est = w->bw_ns_est;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 92) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 93) w->bw_ns_est = westwood_do_filter(w->bw_ns_est, w->bk / delta);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 94) w->bw_est = westwood_do_filter(w->bw_est, w->bw_ns_est);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 95) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 96) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 97)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 98) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 99) * @westwood_pkts_acked
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 100) * Called after processing group of packets.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 101) * but all westwood needs is the last sample of srtt.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 102) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 103) static void tcp_westwood_pkts_acked(struct sock *sk,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 104) const struct ack_sample *sample)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 105) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 106) struct westwood *w = inet_csk_ca(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 107)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 108) if (sample->rtt_us > 0)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 109) w->rtt = usecs_to_jiffies(sample->rtt_us);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 110) }
^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) * @westwood_update_window
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 114) * It updates RTT evaluation window if it is the right moment to do
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 115) * it. If so it calls filter for evaluating bandwidth.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 116) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 117) static void westwood_update_window(struct sock *sk)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 118) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 119) struct westwood *w = inet_csk_ca(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 120) s32 delta = tcp_jiffies32 - w->rtt_win_sx;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 121)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 122) /* Initialize w->snd_una with the first acked sequence number in order
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 123) * to fix mismatch between tp->snd_una and w->snd_una for the first
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 124) * bandwidth sample
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 125) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 126) if (w->first_ack) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 127) w->snd_una = tcp_sk(sk)->snd_una;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 128) w->first_ack = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 129) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 130)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 131) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 132) * See if a RTT-window has passed.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 133) * Be careful since if RTT is less than
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 134) * 50ms we don't filter but we continue 'building the sample'.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 135) * This minimum limit was chosen since an estimation on small
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 136) * time intervals is better to avoid...
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 137) * Obviously on a LAN we reasonably will always have
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 138) * right_bound = left_bound + WESTWOOD_RTT_MIN
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 139) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 140) if (w->rtt && delta > max_t(u32, w->rtt, TCP_WESTWOOD_RTT_MIN)) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 141) westwood_filter(w, delta);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 142)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 143) w->bk = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 144) w->rtt_win_sx = tcp_jiffies32;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 145) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 146) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 147)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 148) static inline void update_rtt_min(struct westwood *w)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 149) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 150) if (w->reset_rtt_min) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 151) w->rtt_min = w->rtt;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 152) w->reset_rtt_min = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 153) } else
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 154) w->rtt_min = min(w->rtt, w->rtt_min);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 155) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 156)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 157) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 158) * @westwood_fast_bw
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 159) * It is called when we are in fast path. In particular it is called when
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 160) * header prediction is successful. In such case in fact update is
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 161) * straight forward and doesn't need any particular care.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 162) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 163) static inline void westwood_fast_bw(struct sock *sk)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 164) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 165) const struct tcp_sock *tp = tcp_sk(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 166) struct westwood *w = inet_csk_ca(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 167)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 168) westwood_update_window(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 169)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 170) w->bk += tp->snd_una - w->snd_una;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 171) w->snd_una = tp->snd_una;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 172) update_rtt_min(w);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 173) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 174)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 175) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 176) * @westwood_acked_count
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 177) * This function evaluates cumul_ack for evaluating bk in case of
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 178) * delayed or partial acks.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 179) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 180) static inline u32 westwood_acked_count(struct sock *sk)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 181) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 182) const struct tcp_sock *tp = tcp_sk(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 183) struct westwood *w = inet_csk_ca(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 184)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 185) w->cumul_ack = tp->snd_una - w->snd_una;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 186)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 187) /* If cumul_ack is 0 this is a dupack since it's not moving
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 188) * tp->snd_una.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 189) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 190) if (!w->cumul_ack) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 191) w->accounted += tp->mss_cache;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 192) w->cumul_ack = tp->mss_cache;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 193) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 194)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 195) if (w->cumul_ack > tp->mss_cache) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 196) /* Partial or delayed ack */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 197) if (w->accounted >= w->cumul_ack) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 198) w->accounted -= w->cumul_ack;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 199) w->cumul_ack = tp->mss_cache;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 200) } else {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 201) w->cumul_ack -= w->accounted;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 202) w->accounted = 0;
^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)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 206) w->snd_una = tp->snd_una;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 207)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 208) return w->cumul_ack;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 209) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 210)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 211) /*
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 212) * TCP Westwood
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 213) * Here limit is evaluated as Bw estimation*RTTmin (for obtaining it
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 214) * in packets we use mss_cache). Rttmin is guaranteed to be >= 2
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 215) * so avoids ever returning 0.
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 216) */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 217) static u32 tcp_westwood_bw_rttmin(const struct sock *sk)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 218) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 219) const struct tcp_sock *tp = tcp_sk(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 220) const struct westwood *w = inet_csk_ca(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 221)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 222) return max_t(u32, (w->bw_est * w->rtt_min) / tp->mss_cache, 2);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 223) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 224)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 225) static void tcp_westwood_ack(struct sock *sk, u32 ack_flags)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 226) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 227) if (ack_flags & CA_ACK_SLOWPATH) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 228) struct westwood *w = inet_csk_ca(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 229)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 230) westwood_update_window(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 231) w->bk += westwood_acked_count(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 232)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 233) update_rtt_min(w);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 234) return;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 235) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 236)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 237) westwood_fast_bw(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 238) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 239)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 240) static void tcp_westwood_event(struct sock *sk, enum tcp_ca_event event)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 241) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 242) struct tcp_sock *tp = tcp_sk(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 243) struct westwood *w = inet_csk_ca(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 244)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 245) switch (event) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 246) case CA_EVENT_COMPLETE_CWR:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 247) tp->snd_cwnd = tp->snd_ssthresh = tcp_westwood_bw_rttmin(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 248) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 249) case CA_EVENT_LOSS:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 250) tp->snd_ssthresh = tcp_westwood_bw_rttmin(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 251) /* Update RTT_min when next ack arrives */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 252) w->reset_rtt_min = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 253) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 254) default:
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 255) /* don't care */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 256) break;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 257) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 258) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 259)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 260) /* Extract info for Tcp socket info provided via netlink. */
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 261) static size_t tcp_westwood_info(struct sock *sk, u32 ext, int *attr,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 262) union tcp_cc_info *info)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 263) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 264) const struct westwood *ca = inet_csk_ca(sk);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 265)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 266) if (ext & (1 << (INET_DIAG_VEGASINFO - 1))) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 267) info->vegas.tcpv_enabled = 1;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 268) info->vegas.tcpv_rttcnt = 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 269) info->vegas.tcpv_rtt = jiffies_to_usecs(ca->rtt);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 270) info->vegas.tcpv_minrtt = jiffies_to_usecs(ca->rtt_min);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 271)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 272) *attr = INET_DIAG_VEGASINFO;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 273) return sizeof(struct tcpvegas_info);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 274) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 275) return 0;
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 276) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 277)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 278) static struct tcp_congestion_ops tcp_westwood __read_mostly = {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 279) .init = tcp_westwood_init,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 280) .ssthresh = tcp_reno_ssthresh,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 281) .cong_avoid = tcp_reno_cong_avoid,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 282) .undo_cwnd = tcp_reno_undo_cwnd,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 283) .cwnd_event = tcp_westwood_event,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 284) .in_ack_event = tcp_westwood_ack,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 285) .get_info = tcp_westwood_info,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 286) .pkts_acked = tcp_westwood_pkts_acked,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 287)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 288) .owner = THIS_MODULE,
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 289) .name = "westwood"
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 290) };
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 291)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 292) static int __init tcp_westwood_register(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 293) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 294) BUILD_BUG_ON(sizeof(struct westwood) > ICSK_CA_PRIV_SIZE);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 295) return tcp_register_congestion_control(&tcp_westwood);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 296) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 297)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 298) static void __exit tcp_westwood_unregister(void)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 299) {
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 300) tcp_unregister_congestion_control(&tcp_westwood);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 301) }
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 302)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 303) module_init(tcp_westwood_register);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 304) module_exit(tcp_westwood_unregister);
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 305)
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 306) MODULE_AUTHOR("Stephen Hemminger, Angelo Dell'Aera");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 307) MODULE_LICENSE("GPL");
^8f3ce5b39 (kx 2023-10-28 12:00:06 +0300 308) MODULE_DESCRIPTION("TCP Westwood+");
Orange Pi5 kernel
Deprecated Linux kernel 5.10.110 for OrangePi 5/5B/5+ boards
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