17931287dSThomas Gleixner // SPDX-License-Identifier: GPL-2.0-or-later 27c657876SArnaldo Carvalho de Melo /* 3954c2db8SGerrit Renker * Copyright (c) 2007 The University of Aberdeen, Scotland, UK 4b2f41ff4SIan McDonald * Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand. 5b2f41ff4SIan McDonald * Copyright (c) 2005-7 Ian McDonald <ian.mcdonald@jandi.co.nz> 67c657876SArnaldo Carvalho de Melo * 77c657876SArnaldo Carvalho de Melo * An implementation of the DCCP protocol 87c657876SArnaldo Carvalho de Melo * 97c657876SArnaldo Carvalho de Melo * This code has been developed by the University of Waikato WAND 10266f3128SAlexander A. Klimov * research group. For further information please see https://www.wand.net.nz/ 117c657876SArnaldo Carvalho de Melo * 127c657876SArnaldo Carvalho de Melo * This code also uses code from Lulea University, rereleased as GPL by its 137c657876SArnaldo Carvalho de Melo * authors: 147c657876SArnaldo Carvalho de Melo * Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon 157c657876SArnaldo Carvalho de Melo * 167c657876SArnaldo Carvalho de Melo * Changes to meet Linux coding standards, to make it meet latest ccid3 draft 177c657876SArnaldo Carvalho de Melo * and to make it work as a loadable module in the DCCP stack written by 187c657876SArnaldo Carvalho de Melo * Arnaldo Carvalho de Melo <acme@conectiva.com.br>. 197c657876SArnaldo Carvalho de Melo * 207c657876SArnaldo Carvalho de Melo * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br> 217c657876SArnaldo Carvalho de Melo */ 227c657876SArnaldo Carvalho de Melo #include "../dccp.h" 237c657876SArnaldo Carvalho de Melo #include "ccid3.h" 247c657876SArnaldo Carvalho de Melo 2576fd1e87SGerrit Renker #include <asm/unaligned.h> 2676fd1e87SGerrit Renker 2756724aa4SGerrit Renker #ifdef CONFIG_IP_DCCP_CCID3_DEBUG 28eb939922SRusty Russell static bool ccid3_debug; 2956724aa4SGerrit Renker #define ccid3_pr_debug(format, a...) DCCP_PR_DEBUG(ccid3_debug, format, ##a) 307c657876SArnaldo Carvalho de Melo #else 317c657876SArnaldo Carvalho de Melo #define ccid3_pr_debug(format, a...) 327c657876SArnaldo Carvalho de Melo #endif 337c657876SArnaldo Carvalho de Melo 349bf17475SGerrit Renker /* 359bf17475SGerrit Renker * Transmitter Half-Connection Routines 369bf17475SGerrit Renker */ 37410e27a4SGerrit Renker #ifdef CONFIG_IP_DCCP_CCID3_DEBUG 38410e27a4SGerrit Renker static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state) 39410e27a4SGerrit Renker { 4036cbd3dcSJan Engelhardt static const char *const ccid3_state_names[] = { 41410e27a4SGerrit Renker [TFRC_SSTATE_NO_SENT] = "NO_SENT", 42410e27a4SGerrit Renker [TFRC_SSTATE_NO_FBACK] = "NO_FBACK", 43410e27a4SGerrit Renker [TFRC_SSTATE_FBACK] = "FBACK", 44410e27a4SGerrit Renker }; 45410e27a4SGerrit Renker 46410e27a4SGerrit Renker return ccid3_state_names[state]; 47410e27a4SGerrit Renker } 48410e27a4SGerrit Renker #endif 49410e27a4SGerrit Renker 50410e27a4SGerrit Renker static void ccid3_hc_tx_set_state(struct sock *sk, 51410e27a4SGerrit Renker enum ccid3_hc_tx_states state) 52410e27a4SGerrit Renker { 53996ccf49SGerrit Renker struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); 54996ccf49SGerrit Renker enum ccid3_hc_tx_states oldstate = hc->tx_state; 55410e27a4SGerrit Renker 56410e27a4SGerrit Renker ccid3_pr_debug("%s(%p) %-8.8s -> %s\n", 57410e27a4SGerrit Renker dccp_role(sk), sk, ccid3_tx_state_name(oldstate), 58410e27a4SGerrit Renker ccid3_tx_state_name(state)); 59410e27a4SGerrit Renker WARN_ON(state == oldstate); 60996ccf49SGerrit Renker hc->tx_state = state; 61410e27a4SGerrit Renker } 627c657876SArnaldo Carvalho de Melo 6317893bc1SGerrit Renker /* 646c08b2cfSGerrit Renker * Compute the initial sending rate X_init in the manner of RFC 3390: 656c08b2cfSGerrit Renker * 66410e27a4SGerrit Renker * X_init = min(4 * s, max(2 * s, 4380 bytes)) / RTT 676c08b2cfSGerrit Renker * 68410e27a4SGerrit Renker * Note that RFC 3390 uses MSS, RFC 4342 refers to RFC 3390, and rfc3448bis 69410e27a4SGerrit Renker * (rev-02) clarifies the use of RFC 3390 with regard to the above formula. 70a21f9f96SGerrit Renker * For consistency with other parts of the code, X_init is scaled by 2^6. 71a21f9f96SGerrit Renker */ 72a21f9f96SGerrit Renker static inline u64 rfc3390_initial_rate(struct sock *sk) 73a21f9f96SGerrit Renker { 74996ccf49SGerrit Renker const struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); 75996ccf49SGerrit Renker const __u32 w_init = clamp_t(__u32, 4380U, 2 * hc->tx_s, 4 * hc->tx_s); 76a21f9f96SGerrit Renker 77996ccf49SGerrit Renker return scaled_div(w_init << 6, hc->tx_rtt); 78a21f9f96SGerrit Renker } 79a21f9f96SGerrit Renker 8020cbd3e1SGerrit Renker /** 8120cbd3e1SGerrit Renker * ccid3_update_send_interval - Calculate new t_ipi = s / X_inst 8220cbd3e1SGerrit Renker * This respects the granularity of X_inst (64 * bytes/second). 8317893bc1SGerrit Renker */ 84996ccf49SGerrit Renker static void ccid3_update_send_interval(struct ccid3_hc_tx_sock *hc) 857c657876SArnaldo Carvalho de Melo { 86996ccf49SGerrit Renker hc->tx_t_ipi = scaled_div32(((u64)hc->tx_s) << 6, hc->tx_x); 87410e27a4SGerrit Renker 88793734b5SGerrit Renker DCCP_BUG_ON(hc->tx_t_ipi == 0); 8920cbd3e1SGerrit Renker ccid3_pr_debug("t_ipi=%u, s=%u, X=%u\n", hc->tx_t_ipi, 9095c96174SEric Dumazet hc->tx_s, (unsigned int)(hc->tx_x >> 6)); 917c657876SArnaldo Carvalho de Melo } 92aa97efd9SGerrit Renker 93996ccf49SGerrit Renker static u32 ccid3_hc_tx_idle_rtt(struct ccid3_hc_tx_sock *hc, ktime_t now) 94a5358fdcSGerrit Renker { 95996ccf49SGerrit Renker u32 delta = ktime_us_delta(now, hc->tx_t_last_win_count); 96a5358fdcSGerrit Renker 97996ccf49SGerrit Renker return delta / hc->tx_rtt; 98a5358fdcSGerrit Renker } 99a5358fdcSGerrit Renker 100aa97efd9SGerrit Renker /** 101aa97efd9SGerrit Renker * ccid3_hc_tx_update_x - Update allowed sending rate X 102aa97efd9SGerrit Renker * @stamp: most recent time if available - can be left NULL. 1032c53040fSBen Hutchings * 104aa97efd9SGerrit Renker * This function tracks draft rfc3448bis, check there for latest details. 1055c3fbb6aSGerrit Renker * 1061a21e49aSGerrit Renker * Note: X and X_recv are both stored in units of 64 * bytes/second, to support 1071a21e49aSGerrit Renker * fine-grained resolution of sending rates. This requires scaling by 2^6 1081a21e49aSGerrit Renker * throughout the code. Only X_calc is unscaled (in bytes/second). 1091a21e49aSGerrit Renker * 1107c657876SArnaldo Carvalho de Melo */ 111aa97efd9SGerrit Renker static void ccid3_hc_tx_update_x(struct sock *sk, ktime_t *stamp) 1127c657876SArnaldo Carvalho de Melo { 113996ccf49SGerrit Renker struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); 114996ccf49SGerrit Renker __u64 min_rate = 2 * hc->tx_x_recv; 115996ccf49SGerrit Renker const __u64 old_x = hc->tx_x; 116aa97efd9SGerrit Renker ktime_t now = stamp ? *stamp : ktime_get_real(); 1177c657876SArnaldo Carvalho de Melo 1180c150efbSGerrit Renker /* 1190c150efbSGerrit Renker * Handle IDLE periods: do not reduce below RFC3390 initial sending rate 120a5358fdcSGerrit Renker * when idling [RFC 4342, 5.1]. Definition of idling is from rfc3448bis: 121a5358fdcSGerrit Renker * a sender is idle if it has not sent anything over a 2-RTT-period. 1220c150efbSGerrit Renker * For consistency with X and X_recv, min_rate is also scaled by 2^6. 1230c150efbSGerrit Renker */ 124996ccf49SGerrit Renker if (ccid3_hc_tx_idle_rtt(hc, now) >= 2) { 1250c150efbSGerrit Renker min_rate = rfc3390_initial_rate(sk); 126996ccf49SGerrit Renker min_rate = max(min_rate, 2 * hc->tx_x_recv); 1270c150efbSGerrit Renker } 1280c150efbSGerrit Renker 129996ccf49SGerrit Renker if (hc->tx_p > 0) { 1301a21e49aSGerrit Renker 131996ccf49SGerrit Renker hc->tx_x = min(((__u64)hc->tx_x_calc) << 6, min_rate); 132996ccf49SGerrit Renker hc->tx_x = max(hc->tx_x, (((__u64)hc->tx_s) << 6) / TFRC_T_MBI); 133b6ee3d4aSArnaldo Carvalho de Melo 134996ccf49SGerrit Renker } else if (ktime_us_delta(now, hc->tx_t_ld) - (s64)hc->tx_rtt >= 0) { 1351a21e49aSGerrit Renker 136996ccf49SGerrit Renker hc->tx_x = min(2 * hc->tx_x, min_rate); 137996ccf49SGerrit Renker hc->tx_x = max(hc->tx_x, 138996ccf49SGerrit Renker scaled_div(((__u64)hc->tx_s) << 6, hc->tx_rtt)); 139996ccf49SGerrit Renker hc->tx_t_ld = now; 140ac198ea8SArnaldo Carvalho de Melo } 141a79ef76fSGerrit Renker 142996ccf49SGerrit Renker if (hc->tx_x != old_x) { 1431761f7d7SGerrit Renker ccid3_pr_debug("X_prev=%u, X_now=%u, X_calc=%u, " 14495c96174SEric Dumazet "X_recv=%u\n", (unsigned int)(old_x >> 6), 14595c96174SEric Dumazet (unsigned int)(hc->tx_x >> 6), hc->tx_x_calc, 14695c96174SEric Dumazet (unsigned int)(hc->tx_x_recv >> 6)); 1478699be7dSIan McDonald 148996ccf49SGerrit Renker ccid3_update_send_interval(hc); 1497c657876SArnaldo Carvalho de Melo } 1508699be7dSIan McDonald } 1517c657876SArnaldo Carvalho de Melo 1522c53040fSBen Hutchings /** 1532c53040fSBen Hutchings * ccid3_hc_tx_update_s - Track the mean packet size `s' 154410e27a4SGerrit Renker * @len: DCCP packet payload size in bytes 1552c53040fSBen Hutchings * 1562c53040fSBen Hutchings * cf. RFC 4342, 5.3 and RFC 3448, 4.1 15778ad713dSGerrit Renker */ 158996ccf49SGerrit Renker static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hc, int len) 15978ad713dSGerrit Renker { 160996ccf49SGerrit Renker const u16 old_s = hc->tx_s; 161410e27a4SGerrit Renker 162996ccf49SGerrit Renker hc->tx_s = tfrc_ewma(hc->tx_s, len, 9); 163410e27a4SGerrit Renker 164996ccf49SGerrit Renker if (hc->tx_s != old_s) 165996ccf49SGerrit Renker ccid3_update_send_interval(hc); 16678ad713dSGerrit Renker } 16778ad713dSGerrit Renker 1689f8681dbSGerrit Renker /* 1699f8681dbSGerrit Renker * Update Window Counter using the algorithm from [RFC 4342, 8.1]. 170825de27dSGerrit Renker * As elsewhere, RTT > 0 is assumed by using dccp_sample_rtt(). 1719f8681dbSGerrit Renker */ 172996ccf49SGerrit Renker static inline void ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock *hc, 1738132da4dSGerrit Renker ktime_t now) 1749f8681dbSGerrit Renker { 175996ccf49SGerrit Renker u32 delta = ktime_us_delta(now, hc->tx_t_last_win_count), 176996ccf49SGerrit Renker quarter_rtts = (4 * delta) / hc->tx_rtt; 1779f8681dbSGerrit Renker 1789f8681dbSGerrit Renker if (quarter_rtts > 0) { 179996ccf49SGerrit Renker hc->tx_t_last_win_count = now; 180996ccf49SGerrit Renker hc->tx_last_win_count += min(quarter_rtts, 5U); 181996ccf49SGerrit Renker hc->tx_last_win_count &= 0xF; /* mod 16 */ 1829f8681dbSGerrit Renker } 1839f8681dbSGerrit Renker } 1849f8681dbSGerrit Renker 185839a6094SKees Cook static void ccid3_hc_tx_no_feedback_timer(struct timer_list *t) 1867c657876SArnaldo Carvalho de Melo { 187839a6094SKees Cook struct ccid3_hc_tx_sock *hc = from_timer(hc, t, tx_no_feedback_timer); 188839a6094SKees Cook struct sock *sk = hc->sk; 1892a1fda6fSGerrit Renker unsigned long t_nfb = USEC_PER_SEC / 5; 1907c657876SArnaldo Carvalho de Melo 1917c657876SArnaldo Carvalho de Melo bh_lock_sock(sk); 1927c657876SArnaldo Carvalho de Melo if (sock_owned_by_user(sk)) { 1937c657876SArnaldo Carvalho de Melo /* Try again later. */ 1947c657876SArnaldo Carvalho de Melo /* XXX: set some sensible MIB */ 19548e03eeeSGerrit Renker goto restart_timer; 1967c657876SArnaldo Carvalho de Melo } 1977c657876SArnaldo Carvalho de Melo 198410e27a4SGerrit Renker ccid3_pr_debug("%s(%p, state=%s) - entry\n", dccp_role(sk), sk, 199996ccf49SGerrit Renker ccid3_tx_state_name(hc->tx_state)); 2007c657876SArnaldo Carvalho de Melo 20180763dfbSGerrit Renker /* Ignore and do not restart after leaving the established state */ 20280763dfbSGerrit Renker if ((1 << sk->sk_state) & ~(DCCPF_OPEN | DCCPF_PARTOPEN)) 20380763dfbSGerrit Renker goto out; 20480763dfbSGerrit Renker 20580763dfbSGerrit Renker /* Reset feedback state to "no feedback received" */ 206996ccf49SGerrit Renker if (hc->tx_state == TFRC_SSTATE_FBACK) 207410e27a4SGerrit Renker ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK); 208d0995e6aSGerrit Renker 20952515e77SGerrit Renker /* 21052515e77SGerrit Renker * Determine new allowed sending rate X as per draft rfc3448bis-00, 4.4 21167b67e36SGerrit Renker * RTO is 0 if and only if no feedback has been received yet. 21252515e77SGerrit Renker */ 21367b67e36SGerrit Renker if (hc->tx_t_rto == 0 || hc->tx_p == 0) { 21452515e77SGerrit Renker 21552515e77SGerrit Renker /* halve send rate directly */ 216996ccf49SGerrit Renker hc->tx_x = max(hc->tx_x / 2, 217996ccf49SGerrit Renker (((__u64)hc->tx_s) << 6) / TFRC_T_MBI); 218996ccf49SGerrit Renker ccid3_update_send_interval(hc); 21952515e77SGerrit Renker } else { 2201f2333aeSArnaldo Carvalho de Melo /* 22152515e77SGerrit Renker * Modify the cached value of X_recv 222ff586298SGerrit Renker * 22352515e77SGerrit Renker * If (X_calc > 2 * X_recv) 2247c657876SArnaldo Carvalho de Melo * X_recv = max(X_recv / 2, s / (2 * t_mbi)); 2257c657876SArnaldo Carvalho de Melo * Else 2267c657876SArnaldo Carvalho de Melo * X_recv = X_calc / 4; 2271a21e49aSGerrit Renker * 2281a21e49aSGerrit Renker * Note that X_recv is scaled by 2^6 while X_calc is not 2297c657876SArnaldo Carvalho de Melo */ 230996ccf49SGerrit Renker if (hc->tx_x_calc > (hc->tx_x_recv >> 5)) 231996ccf49SGerrit Renker hc->tx_x_recv = 232996ccf49SGerrit Renker max(hc->tx_x_recv / 2, 233996ccf49SGerrit Renker (((__u64)hc->tx_s) << 6) / (2*TFRC_T_MBI)); 23452515e77SGerrit Renker else { 235996ccf49SGerrit Renker hc->tx_x_recv = hc->tx_x_calc; 236996ccf49SGerrit Renker hc->tx_x_recv <<= 4; 2379e8efc82SGerrit Renker } 238aa97efd9SGerrit Renker ccid3_hc_tx_update_x(sk, NULL); 23952515e77SGerrit Renker } 24052515e77SGerrit Renker ccid3_pr_debug("Reduced X to %llu/64 bytes/sec\n", 241996ccf49SGerrit Renker (unsigned long long)hc->tx_x); 24252515e77SGerrit Renker 2436b5e633aSArnaldo Carvalho de Melo /* 24452515e77SGerrit Renker * Set new timeout for the nofeedback timer. 2458a508ac2SGerrit Renker * See comments in packet_recv() regarding the value of t_RTO. 2466b5e633aSArnaldo Carvalho de Melo */ 24767b67e36SGerrit Renker if (unlikely(hc->tx_t_rto == 0)) /* no feedback received yet */ 24852515e77SGerrit Renker t_nfb = TFRC_INITIAL_TIMEOUT; 24952515e77SGerrit Renker else 250996ccf49SGerrit Renker t_nfb = max(hc->tx_t_rto, 2 * hc->tx_t_ipi); 2517c657876SArnaldo Carvalho de Melo 25248e03eeeSGerrit Renker restart_timer: 253996ccf49SGerrit Renker sk_reset_timer(sk, &hc->tx_no_feedback_timer, 2542a1fda6fSGerrit Renker jiffies + usecs_to_jiffies(t_nfb)); 2557c657876SArnaldo Carvalho de Melo out: 2567c657876SArnaldo Carvalho de Melo bh_unlock_sock(sk); 2577c657876SArnaldo Carvalho de Melo sock_put(sk); 2587c657876SArnaldo Carvalho de Melo } 2597c657876SArnaldo Carvalho de Melo 260fe84f414SGerrit Renker /** 261fe84f414SGerrit Renker * ccid3_hc_tx_send_packet - Delay-based dequeueing of TX packets 262fe84f414SGerrit Renker * @skb: next packet candidate to send on @sk 2632c53040fSBen Hutchings * 264fe84f414SGerrit Renker * This function uses the convention of ccid_packet_dequeue_eval() and 265fe84f414SGerrit Renker * returns a millisecond-delay value between 0 and t_mbi = 64000 msec. 2667da7f456SGerrit Renker */ 2676b57c93dSGerrit Renker static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb) 2687c657876SArnaldo Carvalho de Melo { 2697c657876SArnaldo Carvalho de Melo struct dccp_sock *dp = dccp_sk(sk); 270996ccf49SGerrit Renker struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); 2718132da4dSGerrit Renker ktime_t now = ktime_get_real(); 2728132da4dSGerrit Renker s64 delay; 2737c657876SArnaldo Carvalho de Melo 2747c657876SArnaldo Carvalho de Melo /* 275da335bafSGerrit Renker * This function is called only for Data and DataAck packets. Sending 276da335bafSGerrit Renker * zero-sized Data(Ack)s is theoretically possible, but for congestion 277da335bafSGerrit Renker * control this case is pathological - ignore it. 2787c657876SArnaldo Carvalho de Melo */ 2796b57c93dSGerrit Renker if (unlikely(skb->len == 0)) 280da335bafSGerrit Renker return -EBADMSG; 2817c657876SArnaldo Carvalho de Melo 28280763dfbSGerrit Renker if (hc->tx_state == TFRC_SSTATE_NO_SENT) { 283996ccf49SGerrit Renker sk_reset_timer(sk, &hc->tx_no_feedback_timer, (jiffies + 2848109b02bSArnaldo Carvalho de Melo usecs_to_jiffies(TFRC_INITIAL_TIMEOUT))); 285996ccf49SGerrit Renker hc->tx_last_win_count = 0; 286996ccf49SGerrit Renker hc->tx_t_last_win_count = now; 28790feeb95SGerrit Renker 28890feeb95SGerrit Renker /* Set t_0 for initial packet */ 289996ccf49SGerrit Renker hc->tx_t_nom = now; 290410e27a4SGerrit Renker 291996ccf49SGerrit Renker hc->tx_s = skb->len; 29230833ffeSGerrit Renker 29330833ffeSGerrit Renker /* 29430833ffeSGerrit Renker * Use initial RTT sample when available: recommended by erratum 29530833ffeSGerrit Renker * to RFC 4342. This implements the initialisation procedure of 29630833ffeSGerrit Renker * draft rfc3448bis, section 4.2. Remember, X is scaled by 2^6. 29730833ffeSGerrit Renker */ 29830833ffeSGerrit Renker if (dp->dccps_syn_rtt) { 29930833ffeSGerrit Renker ccid3_pr_debug("SYN RTT = %uus\n", dp->dccps_syn_rtt); 300996ccf49SGerrit Renker hc->tx_rtt = dp->dccps_syn_rtt; 301996ccf49SGerrit Renker hc->tx_x = rfc3390_initial_rate(sk); 302996ccf49SGerrit Renker hc->tx_t_ld = now; 30330833ffeSGerrit Renker } else { 3043294f202SGerrit Renker /* 3053294f202SGerrit Renker * Sender does not have RTT sample: 3063294f202SGerrit Renker * - set fallback RTT (RFC 4340, 3.4) since a RTT value 3073294f202SGerrit Renker * is needed in several parts (e.g. window counter); 3083294f202SGerrit Renker * - set sending rate X_pps = 1pps as per RFC 3448, 4.2. 3093294f202SGerrit Renker */ 310996ccf49SGerrit Renker hc->tx_rtt = DCCP_FALLBACK_RTT; 311996ccf49SGerrit Renker hc->tx_x = hc->tx_s; 312996ccf49SGerrit Renker hc->tx_x <<= 6; 31330833ffeSGerrit Renker } 314996ccf49SGerrit Renker ccid3_update_send_interval(hc); 31530833ffeSGerrit Renker 316410e27a4SGerrit Renker ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK); 31780763dfbSGerrit Renker 31880763dfbSGerrit Renker } else { 319996ccf49SGerrit Renker delay = ktime_us_delta(hc->tx_t_nom, now); 3208699be7dSIan McDonald ccid3_pr_debug("delay=%ld\n", (long)delay); 32191cf5a17SGerrit Renker /* 32220cbd3e1SGerrit Renker * Scheduling of packet transmissions (RFC 5348, 8.3) 32391cf5a17SGerrit Renker * 32491cf5a17SGerrit Renker * if (t_now > t_nom - delta) 32591cf5a17SGerrit Renker * // send the packet now 32691cf5a17SGerrit Renker * else 32791cf5a17SGerrit Renker * // send the packet in (t_nom - t_now) milliseconds. 32891cf5a17SGerrit Renker */ 32920cbd3e1SGerrit Renker if (delay >= TFRC_T_DELTA) 33020cbd3e1SGerrit Renker return (u32)delay / USEC_PER_MSEC; 3319f8681dbSGerrit Renker 332996ccf49SGerrit Renker ccid3_hc_tx_update_win_count(hc, now); 3337c657876SArnaldo Carvalho de Melo } 3347c657876SArnaldo Carvalho de Melo 3357da7f456SGerrit Renker /* prepare to send now (add options etc.) */ 336507d37cfSArnaldo Carvalho de Melo dp->dccps_hc_tx_insert_options = 1; 337996ccf49SGerrit Renker DCCP_SKB_CB(skb)->dccpd_ccval = hc->tx_last_win_count; 338e312d100SGerrit Renker 339e312d100SGerrit Renker /* set the nominal send time for the next following packet */ 340996ccf49SGerrit Renker hc->tx_t_nom = ktime_add_us(hc->tx_t_nom, hc->tx_t_ipi); 341fe84f414SGerrit Renker return CCID_PACKET_SEND_AT_ONCE; 3427c657876SArnaldo Carvalho de Melo } 3437c657876SArnaldo Carvalho de Melo 344baf9e782SGerrit Renker static void ccid3_hc_tx_packet_sent(struct sock *sk, unsigned int len) 3457c657876SArnaldo Carvalho de Melo { 346996ccf49SGerrit Renker struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); 3477c657876SArnaldo Carvalho de Melo 348996ccf49SGerrit Renker ccid3_hc_tx_update_s(hc, len); 34978ad713dSGerrit Renker 350996ccf49SGerrit Renker if (tfrc_tx_hist_add(&hc->tx_hist, dccp_sk(sk)->dccps_gss)) 351c5a1ae9aSGerrit Renker DCCP_CRIT("packet history - out of memory!"); 3527c657876SArnaldo Carvalho de Melo } 3537c657876SArnaldo Carvalho de Melo 3547c657876SArnaldo Carvalho de Melo static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) 3557c657876SArnaldo Carvalho de Melo { 356996ccf49SGerrit Renker struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); 357d2c72630SGerrit Renker struct tfrc_tx_hist_entry *acked; 3580740d49cSArnaldo Carvalho de Melo ktime_t now; 3592a1fda6fSGerrit Renker unsigned long t_nfb; 360536bb20bSGerrit Renker u32 r_sample; 3611f2333aeSArnaldo Carvalho de Melo 3627c657876SArnaldo Carvalho de Melo /* we are only interested in ACKs */ 3637c657876SArnaldo Carvalho de Melo if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK || 3647c657876SArnaldo Carvalho de Melo DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK)) 3657c657876SArnaldo Carvalho de Melo return; 366d2c72630SGerrit Renker /* 367d2c72630SGerrit Renker * Locate the acknowledged packet in the TX history. 368d2c72630SGerrit Renker * 369d2c72630SGerrit Renker * Returning "entry not found" here can for instance happen when 370d2c72630SGerrit Renker * - the host has not sent out anything (e.g. a passive server), 371d2c72630SGerrit Renker * - the Ack is outdated (packet with higher Ack number was received), 372d2c72630SGerrit Renker * - it is a bogus Ack (for a packet not sent on this connection). 373d2c72630SGerrit Renker */ 374d2c72630SGerrit Renker acked = tfrc_tx_hist_find_entry(hc->tx_hist, dccp_hdr_ack_seq(skb)); 375d2c72630SGerrit Renker if (acked == NULL) 376410e27a4SGerrit Renker return; 377d2c72630SGerrit Renker /* For the sake of RTT sampling, ignore/remove all older entries */ 378d2c72630SGerrit Renker tfrc_tx_hist_purge(&acked->next); 379d2c72630SGerrit Renker 380d2c72630SGerrit Renker /* Update the moving average for the RTT estimate (RFC 3448, 4.3) */ 381d2c72630SGerrit Renker now = ktime_get_real(); 382d2c72630SGerrit Renker r_sample = dccp_sample_rtt(sk, ktime_us_delta(now, acked->stamp)); 383d2c72630SGerrit Renker hc->tx_rtt = tfrc_ewma(hc->tx_rtt, r_sample, 9); 384410e27a4SGerrit Renker 3851a21e49aSGerrit Renker /* 386d8d1252fSGerrit Renker * Update allowed sending rate X as per draft rfc3448bis-00, 4.2/3 387d8d1252fSGerrit Renker */ 388996ccf49SGerrit Renker if (hc->tx_state == TFRC_SSTATE_NO_FBACK) { 389410e27a4SGerrit Renker ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK); 390d8d1252fSGerrit Renker 391996ccf49SGerrit Renker if (hc->tx_t_rto == 0) { 392d8d1252fSGerrit Renker /* 393d8d1252fSGerrit Renker * Initial feedback packet: Larger Initial Windows (4.2) 3941a21e49aSGerrit Renker */ 395996ccf49SGerrit Renker hc->tx_x = rfc3390_initial_rate(sk); 396996ccf49SGerrit Renker hc->tx_t_ld = now; 397a79ef76fSGerrit Renker 398996ccf49SGerrit Renker ccid3_update_send_interval(hc); 3995c3fbb6aSGerrit Renker 400d8d1252fSGerrit Renker goto done_computing_x; 401996ccf49SGerrit Renker } else if (hc->tx_p == 0) { 402d8d1252fSGerrit Renker /* 403d8d1252fSGerrit Renker * First feedback after nofeedback timer expiry (4.3) 404d8d1252fSGerrit Renker */ 405d8d1252fSGerrit Renker goto done_computing_x; 406d8d1252fSGerrit Renker } 407d8d1252fSGerrit Renker } 4085c3fbb6aSGerrit Renker 409ff586298SGerrit Renker /* Update sending rate (step 4 of [RFC 3448, 4.3]) */ 410996ccf49SGerrit Renker if (hc->tx_p > 0) 411996ccf49SGerrit Renker hc->tx_x_calc = tfrc_calc_x(hc->tx_s, hc->tx_rtt, hc->tx_p); 412aa97efd9SGerrit Renker ccid3_hc_tx_update_x(sk, &now); 4137c657876SArnaldo Carvalho de Melo 414d8d1252fSGerrit Renker done_computing_x: 4157dfee1a9SGerrit Renker ccid3_pr_debug("%s(%p), RTT=%uus (sample=%uus), s=%u, " 4168109b02bSArnaldo Carvalho de Melo "p=%u, X_calc=%u, X_recv=%u, X=%u\n", 417996ccf49SGerrit Renker dccp_role(sk), sk, hc->tx_rtt, r_sample, 418996ccf49SGerrit Renker hc->tx_s, hc->tx_p, hc->tx_x_calc, 41995c96174SEric Dumazet (unsigned int)(hc->tx_x_recv >> 6), 42095c96174SEric Dumazet (unsigned int)(hc->tx_x >> 6)); 4217c657876SArnaldo Carvalho de Melo 4227c657876SArnaldo Carvalho de Melo /* unschedule no feedback timer */ 423996ccf49SGerrit Renker sk_stop_timer(sk, &hc->tx_no_feedback_timer); 4247c657876SArnaldo Carvalho de Melo 425c530cfb1SArnaldo Carvalho de Melo /* 4268109b02bSArnaldo Carvalho de Melo * As we have calculated new ipi, delta, t_nom it is possible 4278109b02bSArnaldo Carvalho de Melo * that we now can send a packet, so wake up dccp_wait_for_ccid 428c530cfb1SArnaldo Carvalho de Melo */ 429c530cfb1SArnaldo Carvalho de Melo sk->sk_write_space(sk); 4308c60f3faSArnaldo Carvalho de Melo 4318a508ac2SGerrit Renker /* 43289858ad1SGerrit Renker * Update timeout interval for the nofeedback timer. In order to control 43389858ad1SGerrit Renker * rate halving on networks with very low RTTs (<= 1 ms), use per-route 43489858ad1SGerrit Renker * tunable RTAX_RTO_MIN value as the lower bound. 4358a508ac2SGerrit Renker */ 43689858ad1SGerrit Renker hc->tx_t_rto = max_t(u32, 4 * hc->tx_rtt, 43789858ad1SGerrit Renker USEC_PER_SEC/HZ * tcp_rto_min(sk)); 4381f2333aeSArnaldo Carvalho de Melo /* 4391f2333aeSArnaldo Carvalho de Melo * Schedule no feedback timer to expire in 4408a508ac2SGerrit Renker * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi) 4411f2333aeSArnaldo Carvalho de Melo */ 442996ccf49SGerrit Renker t_nfb = max(hc->tx_t_rto, 2 * hc->tx_t_ipi); 4437c657876SArnaldo Carvalho de Melo 444a9672411SGerrit Renker ccid3_pr_debug("%s(%p), Scheduled no feedback timer to " 4458109b02bSArnaldo Carvalho de Melo "expire in %lu jiffies (%luus)\n", 446388d5e99SGerrit Renker dccp_role(sk), sk, usecs_to_jiffies(t_nfb), t_nfb); 4477c657876SArnaldo Carvalho de Melo 448996ccf49SGerrit Renker sk_reset_timer(sk, &hc->tx_no_feedback_timer, 4492a1fda6fSGerrit Renker jiffies + usecs_to_jiffies(t_nfb)); 4507c657876SArnaldo Carvalho de Melo } 4517c657876SArnaldo Carvalho de Melo 4524874c131SGerrit Renker static int ccid3_hc_tx_parse_options(struct sock *sk, u8 packet_type, 4534874c131SGerrit Renker u8 option, u8 *optval, u8 optlen) 4547c657876SArnaldo Carvalho de Melo { 455996ccf49SGerrit Renker struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); 45676fd1e87SGerrit Renker __be32 opt_val; 4577c657876SArnaldo Carvalho de Melo 4587c657876SArnaldo Carvalho de Melo switch (option) { 45937efb03fSGerrit Renker case TFRC_OPT_RECEIVE_RATE: 4607c657876SArnaldo Carvalho de Melo case TFRC_OPT_LOSS_EVENT_RATE: 4614874c131SGerrit Renker /* Must be ignored on Data packets, cf. RFC 4342 8.3 and 8.5 */ 4624874c131SGerrit Renker if (packet_type == DCCP_PKT_DATA) 4634874c131SGerrit Renker break; 4644874c131SGerrit Renker if (unlikely(optlen != 4)) { 46537efb03fSGerrit Renker DCCP_WARN("%s(%p), invalid len %d for %u\n", 4664874c131SGerrit Renker dccp_role(sk), sk, optlen, option); 46737efb03fSGerrit Renker return -EINVAL; 46847a61e7bSGerrit Renker } 4694874c131SGerrit Renker opt_val = ntohl(get_unaligned((__be32 *)optval)); 470410e27a4SGerrit Renker 47137efb03fSGerrit Renker if (option == TFRC_OPT_RECEIVE_RATE) { 472536bb20bSGerrit Renker /* Receive Rate is kept in units of 64 bytes/second */ 473536bb20bSGerrit Renker hc->tx_x_recv = opt_val; 474536bb20bSGerrit Renker hc->tx_x_recv <<= 6; 475536bb20bSGerrit Renker 47637efb03fSGerrit Renker ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n", 47737efb03fSGerrit Renker dccp_role(sk), sk, opt_val); 47837efb03fSGerrit Renker } else { 479536bb20bSGerrit Renker /* Update the fixpoint Loss Event Rate fraction */ 480536bb20bSGerrit Renker hc->tx_p = tfrc_invert_loss_event_rate(opt_val); 481536bb20bSGerrit Renker 48237efb03fSGerrit Renker ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n", 48337efb03fSGerrit Renker dccp_role(sk), sk, opt_val); 48437efb03fSGerrit Renker } 48537efb03fSGerrit Renker } 48637efb03fSGerrit Renker return 0; 4877c657876SArnaldo Carvalho de Melo } 4887c657876SArnaldo Carvalho de Melo 48991f0ebf7SArnaldo Carvalho de Melo static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk) 4907c657876SArnaldo Carvalho de Melo { 491996ccf49SGerrit Renker struct ccid3_hc_tx_sock *hc = ccid_priv(ccid); 4927c657876SArnaldo Carvalho de Melo 493996ccf49SGerrit Renker hc->tx_state = TFRC_SSTATE_NO_SENT; 494996ccf49SGerrit Renker hc->tx_hist = NULL; 495839a6094SKees Cook hc->sk = sk; 496839a6094SKees Cook timer_setup(&hc->tx_no_feedback_timer, 497839a6094SKees Cook ccid3_hc_tx_no_feedback_timer, 0); 4987c657876SArnaldo Carvalho de Melo return 0; 4997c657876SArnaldo Carvalho de Melo } 5007c657876SArnaldo Carvalho de Melo 5017c657876SArnaldo Carvalho de Melo static void ccid3_hc_tx_exit(struct sock *sk) 5027c657876SArnaldo Carvalho de Melo { 503996ccf49SGerrit Renker struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); 5047c657876SArnaldo Carvalho de Melo 505996ccf49SGerrit Renker sk_stop_timer(sk, &hc->tx_no_feedback_timer); 506996ccf49SGerrit Renker tfrc_tx_hist_purge(&hc->tx_hist); 5077c657876SArnaldo Carvalho de Melo } 5087c657876SArnaldo Carvalho de Melo 5099bf17475SGerrit Renker static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info) 5109bf17475SGerrit Renker { 51151c22bb5SGerrit Renker info->tcpi_rto = ccid3_hc_tx_sk(sk)->tx_t_rto; 51251c22bb5SGerrit Renker info->tcpi_rtt = ccid3_hc_tx_sk(sk)->tx_rtt; 5139bf17475SGerrit Renker } 5149bf17475SGerrit Renker 5159bf17475SGerrit Renker static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len, 5169bf17475SGerrit Renker u32 __user *optval, int __user *optlen) 5179bf17475SGerrit Renker { 51851c22bb5SGerrit Renker const struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); 51967b67e36SGerrit Renker struct tfrc_tx_info tfrc; 5209bf17475SGerrit Renker const void *val; 5219bf17475SGerrit Renker 5229bf17475SGerrit Renker switch (optname) { 5239bf17475SGerrit Renker case DCCP_SOCKOPT_CCID_TX_INFO: 52467b67e36SGerrit Renker if (len < sizeof(tfrc)) 5259bf17475SGerrit Renker return -EINVAL; 5267b07f8ebSMathias Krause memset(&tfrc, 0, sizeof(tfrc)); 52767b67e36SGerrit Renker tfrc.tfrctx_x = hc->tx_x; 52867b67e36SGerrit Renker tfrc.tfrctx_x_recv = hc->tx_x_recv; 52967b67e36SGerrit Renker tfrc.tfrctx_x_calc = hc->tx_x_calc; 53067b67e36SGerrit Renker tfrc.tfrctx_rtt = hc->tx_rtt; 53167b67e36SGerrit Renker tfrc.tfrctx_p = hc->tx_p; 53267b67e36SGerrit Renker tfrc.tfrctx_rto = hc->tx_t_rto; 53367b67e36SGerrit Renker tfrc.tfrctx_ipi = hc->tx_t_ipi; 53467b67e36SGerrit Renker len = sizeof(tfrc); 53567b67e36SGerrit Renker val = &tfrc; 5369bf17475SGerrit Renker break; 5379bf17475SGerrit Renker default: 5389bf17475SGerrit Renker return -ENOPROTOOPT; 5399bf17475SGerrit Renker } 5409bf17475SGerrit Renker 5419bf17475SGerrit Renker if (put_user(len, optlen) || copy_to_user(optval, val, len)) 5429bf17475SGerrit Renker return -EFAULT; 5439bf17475SGerrit Renker 5449bf17475SGerrit Renker return 0; 5459bf17475SGerrit Renker } 5469bf17475SGerrit Renker 5479bf17475SGerrit Renker /* 5489bf17475SGerrit Renker * Receiver Half-Connection Routines 5499bf17475SGerrit Renker */ 550410e27a4SGerrit Renker 551410e27a4SGerrit Renker /* CCID3 feedback types */ 552410e27a4SGerrit Renker enum ccid3_fback_type { 553410e27a4SGerrit Renker CCID3_FBACK_NONE = 0, 554410e27a4SGerrit Renker CCID3_FBACK_INITIAL, 555410e27a4SGerrit Renker CCID3_FBACK_PERIODIC, 556410e27a4SGerrit Renker CCID3_FBACK_PARAM_CHANGE 557410e27a4SGerrit Renker }; 558410e27a4SGerrit Renker 559410e27a4SGerrit Renker #ifdef CONFIG_IP_DCCP_CCID3_DEBUG 560410e27a4SGerrit Renker static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state) 561410e27a4SGerrit Renker { 56236cbd3dcSJan Engelhardt static const char *const ccid3_rx_state_names[] = { 563410e27a4SGerrit Renker [TFRC_RSTATE_NO_DATA] = "NO_DATA", 564410e27a4SGerrit Renker [TFRC_RSTATE_DATA] = "DATA", 565410e27a4SGerrit Renker }; 566410e27a4SGerrit Renker 567410e27a4SGerrit Renker return ccid3_rx_state_names[state]; 568410e27a4SGerrit Renker } 569410e27a4SGerrit Renker #endif 570410e27a4SGerrit Renker 571410e27a4SGerrit Renker static void ccid3_hc_rx_set_state(struct sock *sk, 572410e27a4SGerrit Renker enum ccid3_hc_rx_states state) 573410e27a4SGerrit Renker { 574996ccf49SGerrit Renker struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk); 575996ccf49SGerrit Renker enum ccid3_hc_rx_states oldstate = hc->rx_state; 576410e27a4SGerrit Renker 577410e27a4SGerrit Renker ccid3_pr_debug("%s(%p) %-8.8s -> %s\n", 578410e27a4SGerrit Renker dccp_role(sk), sk, ccid3_rx_state_name(oldstate), 579410e27a4SGerrit Renker ccid3_rx_state_name(state)); 580410e27a4SGerrit Renker WARN_ON(state == oldstate); 581996ccf49SGerrit Renker hc->rx_state = state; 582410e27a4SGerrit Renker } 583410e27a4SGerrit Renker 584b84a2189SArnaldo Carvalho de Melo static void ccid3_hc_rx_send_feedback(struct sock *sk, 585b84a2189SArnaldo Carvalho de Melo const struct sk_buff *skb, 586b84a2189SArnaldo Carvalho de Melo enum ccid3_fback_type fbtype) 5877c657876SArnaldo Carvalho de Melo { 588996ccf49SGerrit Renker struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk); 589410e27a4SGerrit Renker struct dccp_sock *dp = dccp_sk(sk); 5900ce4e70fSEric Dumazet ktime_t now = ktime_get(); 591410e27a4SGerrit Renker s64 delta = 0; 592410e27a4SGerrit Renker 593b84a2189SArnaldo Carvalho de Melo switch (fbtype) { 594b84a2189SArnaldo Carvalho de Melo case CCID3_FBACK_INITIAL: 595996ccf49SGerrit Renker hc->rx_x_recv = 0; 596996ccf49SGerrit Renker hc->rx_pinv = ~0U; /* see RFC 4342, 8.5 */ 5977c657876SArnaldo Carvalho de Melo break; 598b84a2189SArnaldo Carvalho de Melo case CCID3_FBACK_PARAM_CHANGE: 599b84a2189SArnaldo Carvalho de Melo /* 600b84a2189SArnaldo Carvalho de Melo * When parameters change (new loss or p > p_prev), we do not 601b84a2189SArnaldo Carvalho de Melo * have a reliable estimate for R_m of [RFC 3448, 6.2] and so 602410e27a4SGerrit Renker * need to reuse the previous value of X_recv. However, when 603410e27a4SGerrit Renker * X_recv was 0 (due to early loss), this would kill X down to 604410e27a4SGerrit Renker * s/t_mbi (i.e. one packet in 64 seconds). 605410e27a4SGerrit Renker * To avoid such drastic reduction, we approximate X_recv as 606410e27a4SGerrit Renker * the number of bytes since last feedback. 607410e27a4SGerrit Renker * This is a safe fallback, since X is bounded above by X_calc. 608b84a2189SArnaldo Carvalho de Melo */ 609996ccf49SGerrit Renker if (hc->rx_x_recv > 0) 610b84a2189SArnaldo Carvalho de Melo break; 611df561f66SGustavo A. R. Silva fallthrough; 612b84a2189SArnaldo Carvalho de Melo case CCID3_FBACK_PERIODIC: 613996ccf49SGerrit Renker delta = ktime_us_delta(now, hc->rx_tstamp_last_feedback); 614410e27a4SGerrit Renker if (delta <= 0) 61574174fe5SEric Dumazet delta = 1; 616996ccf49SGerrit Renker hc->rx_x_recv = scaled_div32(hc->rx_bytes_recv, delta); 6177c657876SArnaldo Carvalho de Melo break; 618b84a2189SArnaldo Carvalho de Melo default: 6197c657876SArnaldo Carvalho de Melo return; 6207c657876SArnaldo Carvalho de Melo } 6217c657876SArnaldo Carvalho de Melo 6220ce4e70fSEric Dumazet ccid3_pr_debug("Interval %lldusec, X_recv=%u, 1/p=%u\n", delta, 623996ccf49SGerrit Renker hc->rx_x_recv, hc->rx_pinv); 6247c657876SArnaldo Carvalho de Melo 625996ccf49SGerrit Renker hc->rx_tstamp_last_feedback = now; 626996ccf49SGerrit Renker hc->rx_last_counter = dccp_hdr(skb)->dccph_ccval; 627996ccf49SGerrit Renker hc->rx_bytes_recv = 0; 628410e27a4SGerrit Renker 629410e27a4SGerrit Renker dp->dccps_hc_rx_insert_options = 1; 6307c657876SArnaldo Carvalho de Melo dccp_send_ack(sk); 6317c657876SArnaldo Carvalho de Melo } 6327c657876SArnaldo Carvalho de Melo 6332d0817d1SArnaldo Carvalho de Melo static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb) 6347c657876SArnaldo Carvalho de Melo { 63551c22bb5SGerrit Renker const struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk); 63660fe62e7SAndrea Bittau __be32 x_recv, pinv; 6377c657876SArnaldo Carvalho de Melo 63859d203f9SArnaldo Carvalho de Melo if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN)) 6392d0817d1SArnaldo Carvalho de Melo return 0; 6407c657876SArnaldo Carvalho de Melo 6414fded33bSArnaldo Carvalho de Melo if (dccp_packet_without_ack(skb)) 6422d0817d1SArnaldo Carvalho de Melo return 0; 6434fded33bSArnaldo Carvalho de Melo 644996ccf49SGerrit Renker x_recv = htonl(hc->rx_x_recv); 645996ccf49SGerrit Renker pinv = htonl(hc->rx_pinv); 6462d0817d1SArnaldo Carvalho de Melo 647a7d13fbfSGerrit Renker if (dccp_insert_option(skb, TFRC_OPT_LOSS_EVENT_RATE, 6482d0817d1SArnaldo Carvalho de Melo &pinv, sizeof(pinv)) || 649a7d13fbfSGerrit Renker dccp_insert_option(skb, TFRC_OPT_RECEIVE_RATE, 6502d0817d1SArnaldo Carvalho de Melo &x_recv, sizeof(x_recv))) 6512d0817d1SArnaldo Carvalho de Melo return -1; 6522d0817d1SArnaldo Carvalho de Melo 6532d0817d1SArnaldo Carvalho de Melo return 0; 6547c657876SArnaldo Carvalho de Melo } 6557c657876SArnaldo Carvalho de Melo 656aa1b1ff0SGerrit Renker /** 657aa1b1ff0SGerrit Renker * ccid3_first_li - Implements [RFC 5348, 6.3.1] 658954c2db8SGerrit Renker * 659954c2db8SGerrit Renker * Determine the length of the first loss interval via inverse lookup. 660954c2db8SGerrit Renker * Assume that X_recv can be computed by the throughput equation 661954c2db8SGerrit Renker * s 662954c2db8SGerrit Renker * X_recv = -------- 663954c2db8SGerrit Renker * R * fval 664954c2db8SGerrit Renker * Find some p such that f(p) = fval; return 1/p (scaled). 665954c2db8SGerrit Renker */ 666954c2db8SGerrit Renker static u32 ccid3_first_li(struct sock *sk) 667954c2db8SGerrit Renker { 668996ccf49SGerrit Renker struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk); 6690ce4e70fSEric Dumazet u32 x_recv, p; 6700ce4e70fSEric Dumazet s64 delta; 671954c2db8SGerrit Renker u64 fval; 672954c2db8SGerrit Renker 673996ccf49SGerrit Renker if (hc->rx_rtt == 0) { 674410e27a4SGerrit Renker DCCP_WARN("No RTT estimate available, using fallback RTT\n"); 675996ccf49SGerrit Renker hc->rx_rtt = DCCP_FALLBACK_RTT; 676410e27a4SGerrit Renker } 677d20ed95fSGerrit Renker 6780ce4e70fSEric Dumazet delta = ktime_us_delta(ktime_get(), hc->rx_tstamp_last_feedback); 6790ce4e70fSEric Dumazet if (delta <= 0) 6800ce4e70fSEric Dumazet delta = 1; 681996ccf49SGerrit Renker x_recv = scaled_div32(hc->rx_bytes_recv, delta); 682410e27a4SGerrit Renker if (x_recv == 0) { /* would also trigger divide-by-zero */ 683410e27a4SGerrit Renker DCCP_WARN("X_recv==0\n"); 68467b67e36SGerrit Renker if (hc->rx_x_recv == 0) { 685410e27a4SGerrit Renker DCCP_BUG("stored value of X_recv is zero"); 686410e27a4SGerrit Renker return ~0U; 687410e27a4SGerrit Renker } 68867b67e36SGerrit Renker x_recv = hc->rx_x_recv; 689410e27a4SGerrit Renker } 690954c2db8SGerrit Renker 691996ccf49SGerrit Renker fval = scaled_div(hc->rx_s, hc->rx_rtt); 692410e27a4SGerrit Renker fval = scaled_div32(fval, x_recv); 693954c2db8SGerrit Renker p = tfrc_calc_x_reverse_lookup(fval); 694954c2db8SGerrit Renker 695954c2db8SGerrit Renker ccid3_pr_debug("%s(%p), receive rate=%u bytes/s, implied " 696954c2db8SGerrit Renker "loss rate=%u\n", dccp_role(sk), sk, x_recv, p); 697954c2db8SGerrit Renker 698410e27a4SGerrit Renker return p == 0 ? ~0U : scaled_div(1, p); 699954c2db8SGerrit Renker } 700954c2db8SGerrit Renker 7017c657876SArnaldo Carvalho de Melo static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) 7027c657876SArnaldo Carvalho de Melo { 703996ccf49SGerrit Renker struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk); 704410e27a4SGerrit Renker enum ccid3_fback_type do_feedback = CCID3_FBACK_NONE; 7055b5d0e70SGerrit Renker const u64 ndp = dccp_sk(sk)->dccps_options_received.dccpor_ndp; 706b84a2189SArnaldo Carvalho de Melo const bool is_data_packet = dccp_data_packet(skb); 7071f2333aeSArnaldo Carvalho de Melo 708996ccf49SGerrit Renker if (unlikely(hc->rx_state == TFRC_RSTATE_NO_DATA)) { 709410e27a4SGerrit Renker if (is_data_packet) { 710410e27a4SGerrit Renker const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4; 711410e27a4SGerrit Renker do_feedback = CCID3_FBACK_INITIAL; 712410e27a4SGerrit Renker ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA); 713996ccf49SGerrit Renker hc->rx_s = payload; 714410e27a4SGerrit Renker /* 715388d5e99SGerrit Renker * Not necessary to update rx_bytes_recv here, 716410e27a4SGerrit Renker * since X_recv = 0 for the first feedback packet (cf. 717410e27a4SGerrit Renker * RFC 3448, 6.3) -- gerrit 718410e27a4SGerrit Renker */ 719410e27a4SGerrit Renker } 720410e27a4SGerrit Renker goto update_records; 721410e27a4SGerrit Renker } 722410e27a4SGerrit Renker 723996ccf49SGerrit Renker if (tfrc_rx_hist_duplicate(&hc->rx_hist, skb)) 724410e27a4SGerrit Renker return; /* done receiving */ 725410e27a4SGerrit Renker 726410e27a4SGerrit Renker if (is_data_packet) { 727410e27a4SGerrit Renker const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4; 728410e27a4SGerrit Renker /* 729410e27a4SGerrit Renker * Update moving-average of s and the sum of received payload bytes 730410e27a4SGerrit Renker */ 731996ccf49SGerrit Renker hc->rx_s = tfrc_ewma(hc->rx_s, payload, 9); 732996ccf49SGerrit Renker hc->rx_bytes_recv += payload; 733410e27a4SGerrit Renker } 734410e27a4SGerrit Renker 735d20ed95fSGerrit Renker /* 736d20ed95fSGerrit Renker * Perform loss detection and handle pending losses 737d20ed95fSGerrit Renker */ 738996ccf49SGerrit Renker if (tfrc_rx_handle_loss(&hc->rx_hist, &hc->rx_li_hist, 739410e27a4SGerrit Renker skb, ndp, ccid3_first_li, sk)) { 740410e27a4SGerrit Renker do_feedback = CCID3_FBACK_PARAM_CHANGE; 741410e27a4SGerrit Renker goto done_receiving; 742410e27a4SGerrit Renker } 743410e27a4SGerrit Renker 744996ccf49SGerrit Renker if (tfrc_rx_hist_loss_pending(&hc->rx_hist)) 745410e27a4SGerrit Renker return; /* done receiving */ 746410e27a4SGerrit Renker 74788e97a93SGerrit Renker /* 748410e27a4SGerrit Renker * Handle data packets: RTT sampling and monitoring p 74988e97a93SGerrit Renker */ 750410e27a4SGerrit Renker if (unlikely(!is_data_packet)) 751410e27a4SGerrit Renker goto update_records; 752410e27a4SGerrit Renker 753996ccf49SGerrit Renker if (!tfrc_lh_is_initialised(&hc->rx_li_hist)) { 754996ccf49SGerrit Renker const u32 sample = tfrc_rx_hist_sample_rtt(&hc->rx_hist, skb); 755410e27a4SGerrit Renker /* 756410e27a4SGerrit Renker * Empty loss history: no loss so far, hence p stays 0. 757410e27a4SGerrit Renker * Sample RTT values, since an RTT estimate is required for the 758410e27a4SGerrit Renker * computation of p when the first loss occurs; RFC 3448, 6.3.1. 759410e27a4SGerrit Renker */ 760410e27a4SGerrit Renker if (sample != 0) 761996ccf49SGerrit Renker hc->rx_rtt = tfrc_ewma(hc->rx_rtt, sample, 9); 762410e27a4SGerrit Renker 763996ccf49SGerrit Renker } else if (tfrc_lh_update_i_mean(&hc->rx_li_hist, skb)) { 764410e27a4SGerrit Renker /* 765410e27a4SGerrit Renker * Step (3) of [RFC 3448, 6.1]: Recompute I_mean and, if I_mean 766410e27a4SGerrit Renker * has decreased (resp. p has increased), send feedback now. 767410e27a4SGerrit Renker */ 768410e27a4SGerrit Renker do_feedback = CCID3_FBACK_PARAM_CHANGE; 769410e27a4SGerrit Renker } 770410e27a4SGerrit Renker 771b84a2189SArnaldo Carvalho de Melo /* 772b84a2189SArnaldo Carvalho de Melo * Check if the periodic once-per-RTT feedback is due; RFC 4342, 10.3 773b84a2189SArnaldo Carvalho de Melo */ 774996ccf49SGerrit Renker if (SUB16(dccp_hdr(skb)->dccph_ccval, hc->rx_last_counter) > 3) 775410e27a4SGerrit Renker do_feedback = CCID3_FBACK_PERIODIC; 776410e27a4SGerrit Renker 777410e27a4SGerrit Renker update_records: 778996ccf49SGerrit Renker tfrc_rx_hist_add_packet(&hc->rx_hist, skb, ndp); 779410e27a4SGerrit Renker 780410e27a4SGerrit Renker done_receiving: 781410e27a4SGerrit Renker if (do_feedback) 782410e27a4SGerrit Renker ccid3_hc_rx_send_feedback(sk, skb, do_feedback); 7837c657876SArnaldo Carvalho de Melo } 7847c657876SArnaldo Carvalho de Melo 78591f0ebf7SArnaldo Carvalho de Melo static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk) 7867c657876SArnaldo Carvalho de Melo { 787996ccf49SGerrit Renker struct ccid3_hc_rx_sock *hc = ccid_priv(ccid); 7887c657876SArnaldo Carvalho de Melo 789996ccf49SGerrit Renker hc->rx_state = TFRC_RSTATE_NO_DATA; 790996ccf49SGerrit Renker tfrc_lh_init(&hc->rx_li_hist); 791996ccf49SGerrit Renker return tfrc_rx_hist_alloc(&hc->rx_hist); 7927c657876SArnaldo Carvalho de Melo } 7937c657876SArnaldo Carvalho de Melo 7947c657876SArnaldo Carvalho de Melo static void ccid3_hc_rx_exit(struct sock *sk) 7957c657876SArnaldo Carvalho de Melo { 796996ccf49SGerrit Renker struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk); 7977c657876SArnaldo Carvalho de Melo 798996ccf49SGerrit Renker tfrc_rx_hist_purge(&hc->rx_hist); 799996ccf49SGerrit Renker tfrc_lh_cleanup(&hc->rx_li_hist); 8007c657876SArnaldo Carvalho de Melo } 8017c657876SArnaldo Carvalho de Melo 8022babe1f6SArnaldo Carvalho de Melo static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info) 8032babe1f6SArnaldo Carvalho de Melo { 80451c22bb5SGerrit Renker info->tcpi_ca_state = ccid3_hc_rx_sk(sk)->rx_state; 8052babe1f6SArnaldo Carvalho de Melo info->tcpi_options |= TCPI_OPT_TIMESTAMPS; 80651c22bb5SGerrit Renker info->tcpi_rcv_rtt = ccid3_hc_rx_sk(sk)->rx_rtt; 8072babe1f6SArnaldo Carvalho de Melo } 8082babe1f6SArnaldo Carvalho de Melo 80988f964dbSArnaldo Carvalho de Melo static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len, 81088f964dbSArnaldo Carvalho de Melo u32 __user *optval, int __user *optlen) 81188f964dbSArnaldo Carvalho de Melo { 81251c22bb5SGerrit Renker const struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk); 8138e138e79SGerrit Renker struct tfrc_rx_info rx_info; 81488f964dbSArnaldo Carvalho de Melo const void *val; 81588f964dbSArnaldo Carvalho de Melo 81688f964dbSArnaldo Carvalho de Melo switch (optname) { 81788f964dbSArnaldo Carvalho de Melo case DCCP_SOCKOPT_CCID_RX_INFO: 8188e138e79SGerrit Renker if (len < sizeof(rx_info)) 81988f964dbSArnaldo Carvalho de Melo return -EINVAL; 820996ccf49SGerrit Renker rx_info.tfrcrx_x_recv = hc->rx_x_recv; 821996ccf49SGerrit Renker rx_info.tfrcrx_rtt = hc->rx_rtt; 822792e6d33SGerrit Renker rx_info.tfrcrx_p = tfrc_invert_loss_event_rate(hc->rx_pinv); 8238e138e79SGerrit Renker len = sizeof(rx_info); 8248e138e79SGerrit Renker val = &rx_info; 82588f964dbSArnaldo Carvalho de Melo break; 82688f964dbSArnaldo Carvalho de Melo default: 82788f964dbSArnaldo Carvalho de Melo return -ENOPROTOOPT; 82888f964dbSArnaldo Carvalho de Melo } 82988f964dbSArnaldo Carvalho de Melo 83088f964dbSArnaldo Carvalho de Melo if (put_user(len, optlen) || copy_to_user(optval, val, len)) 83188f964dbSArnaldo Carvalho de Melo return -EFAULT; 83288f964dbSArnaldo Carvalho de Melo 83388f964dbSArnaldo Carvalho de Melo return 0; 83488f964dbSArnaldo Carvalho de Melo } 83588f964dbSArnaldo Carvalho de Melo 836ddebc973SGerrit Renker struct ccid_operations ccid3_ops = { 8373dd9a7c3SIan McDonald .ccid_id = DCCPC_CCID3, 83884a97b0aSGerrit Renker .ccid_name = "TCP-Friendly Rate Control", 83991f0ebf7SArnaldo Carvalho de Melo .ccid_hc_tx_obj_size = sizeof(struct ccid3_hc_tx_sock), 8407c657876SArnaldo Carvalho de Melo .ccid_hc_tx_init = ccid3_hc_tx_init, 8417c657876SArnaldo Carvalho de Melo .ccid_hc_tx_exit = ccid3_hc_tx_exit, 8427c657876SArnaldo Carvalho de Melo .ccid_hc_tx_send_packet = ccid3_hc_tx_send_packet, 8437c657876SArnaldo Carvalho de Melo .ccid_hc_tx_packet_sent = ccid3_hc_tx_packet_sent, 8447c657876SArnaldo Carvalho de Melo .ccid_hc_tx_packet_recv = ccid3_hc_tx_packet_recv, 8457c657876SArnaldo Carvalho de Melo .ccid_hc_tx_parse_options = ccid3_hc_tx_parse_options, 84691f0ebf7SArnaldo Carvalho de Melo .ccid_hc_rx_obj_size = sizeof(struct ccid3_hc_rx_sock), 8477c657876SArnaldo Carvalho de Melo .ccid_hc_rx_init = ccid3_hc_rx_init, 8487c657876SArnaldo Carvalho de Melo .ccid_hc_rx_exit = ccid3_hc_rx_exit, 8497c657876SArnaldo Carvalho de Melo .ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options, 8507c657876SArnaldo Carvalho de Melo .ccid_hc_rx_packet_recv = ccid3_hc_rx_packet_recv, 8512babe1f6SArnaldo Carvalho de Melo .ccid_hc_rx_get_info = ccid3_hc_rx_get_info, 8522babe1f6SArnaldo Carvalho de Melo .ccid_hc_tx_get_info = ccid3_hc_tx_get_info, 85388f964dbSArnaldo Carvalho de Melo .ccid_hc_rx_getsockopt = ccid3_hc_rx_getsockopt, 85488f964dbSArnaldo Carvalho de Melo .ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt, 8557c657876SArnaldo Carvalho de Melo }; 8567c657876SArnaldo Carvalho de Melo 85756724aa4SGerrit Renker #ifdef CONFIG_IP_DCCP_CCID3_DEBUG 85843264991SGerrit Renker module_param(ccid3_debug, bool, 0644); 859ddebc973SGerrit Renker MODULE_PARM_DESC(ccid3_debug, "Enable CCID-3 debug messages"); 86056724aa4SGerrit Renker #endif 861