17c657876SArnaldo Carvalho de Melo /* 2954c2db8SGerrit Renker * Copyright (c) 2007 The University of Aberdeen, Scotland, UK 3b2f41ff4SIan McDonald * Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand. 4b2f41ff4SIan McDonald * Copyright (c) 2005-7 Ian McDonald <ian.mcdonald@jandi.co.nz> 57c657876SArnaldo Carvalho de Melo * 67c657876SArnaldo Carvalho de Melo * An implementation of the DCCP protocol 77c657876SArnaldo Carvalho de Melo * 87c657876SArnaldo Carvalho de Melo * This code has been developed by the University of Waikato WAND 97c657876SArnaldo Carvalho de Melo * research group. For further information please see http://www.wand.net.nz/ 107c657876SArnaldo Carvalho de Melo * 117c657876SArnaldo Carvalho de Melo * This code also uses code from Lulea University, rereleased as GPL by its 127c657876SArnaldo Carvalho de Melo * authors: 137c657876SArnaldo Carvalho de Melo * Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon 147c657876SArnaldo Carvalho de Melo * 157c657876SArnaldo Carvalho de Melo * Changes to meet Linux coding standards, to make it meet latest ccid3 draft 167c657876SArnaldo Carvalho de Melo * and to make it work as a loadable module in the DCCP stack written by 177c657876SArnaldo Carvalho de Melo * Arnaldo Carvalho de Melo <acme@conectiva.com.br>. 187c657876SArnaldo Carvalho de Melo * 197c657876SArnaldo Carvalho de Melo * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br> 207c657876SArnaldo Carvalho de Melo * 217c657876SArnaldo Carvalho de Melo * This program is free software; you can redistribute it and/or modify 227c657876SArnaldo Carvalho de Melo * it under the terms of the GNU General Public License as published by 237c657876SArnaldo Carvalho de Melo * the Free Software Foundation; either version 2 of the License, or 247c657876SArnaldo Carvalho de Melo * (at your option) any later version. 257c657876SArnaldo Carvalho de Melo * 267c657876SArnaldo Carvalho de Melo * This program is distributed in the hope that it will be useful, 277c657876SArnaldo Carvalho de Melo * but WITHOUT ANY WARRANTY; without even the implied warranty of 287c657876SArnaldo Carvalho de Melo * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 297c657876SArnaldo Carvalho de Melo * GNU General Public License for more details. 307c657876SArnaldo Carvalho de Melo * 317c657876SArnaldo Carvalho de Melo * You should have received a copy of the GNU General Public License 327c657876SArnaldo Carvalho de Melo * along with this program; if not, write to the Free Software 337c657876SArnaldo Carvalho de Melo * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 347c657876SArnaldo Carvalho de Melo */ 357c657876SArnaldo Carvalho de Melo #include "../dccp.h" 367c657876SArnaldo Carvalho de Melo #include "ccid3.h" 377c657876SArnaldo Carvalho de Melo 3876fd1e87SGerrit Renker #include <asm/unaligned.h> 3976fd1e87SGerrit Renker 4056724aa4SGerrit Renker #ifdef CONFIG_IP_DCCP_CCID3_DEBUG 4156724aa4SGerrit Renker static int ccid3_debug; 4256724aa4SGerrit Renker #define ccid3_pr_debug(format, a...) DCCP_PR_DEBUG(ccid3_debug, format, ##a) 437c657876SArnaldo Carvalho de Melo #else 447c657876SArnaldo Carvalho de Melo #define ccid3_pr_debug(format, a...) 457c657876SArnaldo Carvalho de Melo #endif 467c657876SArnaldo Carvalho de Melo 479bf17475SGerrit Renker /* 489bf17475SGerrit Renker * Transmitter Half-Connection Routines 499bf17475SGerrit Renker */ 50410e27a4SGerrit Renker #ifdef CONFIG_IP_DCCP_CCID3_DEBUG 51410e27a4SGerrit Renker static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state) 52410e27a4SGerrit Renker { 5336cbd3dcSJan Engelhardt static const char *const ccid3_state_names[] = { 54410e27a4SGerrit Renker [TFRC_SSTATE_NO_SENT] = "NO_SENT", 55410e27a4SGerrit Renker [TFRC_SSTATE_NO_FBACK] = "NO_FBACK", 56410e27a4SGerrit Renker [TFRC_SSTATE_FBACK] = "FBACK", 57410e27a4SGerrit Renker [TFRC_SSTATE_TERM] = "TERM", 58410e27a4SGerrit Renker }; 59410e27a4SGerrit Renker 60410e27a4SGerrit Renker return ccid3_state_names[state]; 61410e27a4SGerrit Renker } 62410e27a4SGerrit Renker #endif 63410e27a4SGerrit Renker 64410e27a4SGerrit Renker static void ccid3_hc_tx_set_state(struct sock *sk, 65410e27a4SGerrit Renker enum ccid3_hc_tx_states state) 66410e27a4SGerrit Renker { 67996ccf49SGerrit Renker struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); 68996ccf49SGerrit Renker enum ccid3_hc_tx_states oldstate = hc->tx_state; 69410e27a4SGerrit Renker 70410e27a4SGerrit Renker ccid3_pr_debug("%s(%p) %-8.8s -> %s\n", 71410e27a4SGerrit Renker dccp_role(sk), sk, ccid3_tx_state_name(oldstate), 72410e27a4SGerrit Renker ccid3_tx_state_name(state)); 73410e27a4SGerrit Renker WARN_ON(state == oldstate); 74996ccf49SGerrit Renker hc->tx_state = state; 75410e27a4SGerrit Renker } 767c657876SArnaldo Carvalho de Melo 7717893bc1SGerrit Renker /* 786c08b2cfSGerrit Renker * Compute the initial sending rate X_init in the manner of RFC 3390: 796c08b2cfSGerrit Renker * 80410e27a4SGerrit Renker * X_init = min(4 * s, max(2 * s, 4380 bytes)) / RTT 816c08b2cfSGerrit Renker * 82410e27a4SGerrit Renker * Note that RFC 3390 uses MSS, RFC 4342 refers to RFC 3390, and rfc3448bis 83410e27a4SGerrit Renker * (rev-02) clarifies the use of RFC 3390 with regard to the above formula. 84a21f9f96SGerrit Renker * For consistency with other parts of the code, X_init is scaled by 2^6. 85a21f9f96SGerrit Renker */ 86a21f9f96SGerrit Renker static inline u64 rfc3390_initial_rate(struct sock *sk) 87a21f9f96SGerrit Renker { 88996ccf49SGerrit Renker const struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); 89996ccf49SGerrit Renker const __u32 w_init = clamp_t(__u32, 4380U, 2 * hc->tx_s, 4 * hc->tx_s); 90a21f9f96SGerrit Renker 91996ccf49SGerrit Renker return scaled_div(w_init << 6, hc->tx_rtt); 92a21f9f96SGerrit Renker } 93a21f9f96SGerrit Renker 9420cbd3e1SGerrit Renker /** 9520cbd3e1SGerrit Renker * ccid3_update_send_interval - Calculate new t_ipi = s / X_inst 9620cbd3e1SGerrit Renker * This respects the granularity of X_inst (64 * bytes/second). 9717893bc1SGerrit Renker */ 98996ccf49SGerrit Renker static void ccid3_update_send_interval(struct ccid3_hc_tx_sock *hc) 997c657876SArnaldo Carvalho de Melo { 100996ccf49SGerrit Renker hc->tx_t_ipi = scaled_div32(((u64)hc->tx_s) << 6, hc->tx_x); 101410e27a4SGerrit Renker 10220cbd3e1SGerrit Renker ccid3_pr_debug("t_ipi=%u, s=%u, X=%u\n", hc->tx_t_ipi, 10320cbd3e1SGerrit Renker hc->tx_s, (unsigned)(hc->tx_x >> 6)); 1047c657876SArnaldo Carvalho de Melo } 105aa97efd9SGerrit Renker 106996ccf49SGerrit Renker static u32 ccid3_hc_tx_idle_rtt(struct ccid3_hc_tx_sock *hc, ktime_t now) 107a5358fdcSGerrit Renker { 108996ccf49SGerrit Renker u32 delta = ktime_us_delta(now, hc->tx_t_last_win_count); 109a5358fdcSGerrit Renker 110996ccf49SGerrit Renker return delta / hc->tx_rtt; 111a5358fdcSGerrit Renker } 112a5358fdcSGerrit Renker 113aa97efd9SGerrit Renker /** 114aa97efd9SGerrit Renker * ccid3_hc_tx_update_x - Update allowed sending rate X 115aa97efd9SGerrit Renker * @stamp: most recent time if available - can be left NULL. 116aa97efd9SGerrit Renker * This function tracks draft rfc3448bis, check there for latest details. 1175c3fbb6aSGerrit Renker * 1181a21e49aSGerrit Renker * Note: X and X_recv are both stored in units of 64 * bytes/second, to support 1191a21e49aSGerrit Renker * fine-grained resolution of sending rates. This requires scaling by 2^6 1201a21e49aSGerrit Renker * throughout the code. Only X_calc is unscaled (in bytes/second). 1211a21e49aSGerrit Renker * 1227c657876SArnaldo Carvalho de Melo */ 123aa97efd9SGerrit Renker static void ccid3_hc_tx_update_x(struct sock *sk, ktime_t *stamp) 1247c657876SArnaldo Carvalho de Melo { 125996ccf49SGerrit Renker struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); 126996ccf49SGerrit Renker __u64 min_rate = 2 * hc->tx_x_recv; 127996ccf49SGerrit Renker const __u64 old_x = hc->tx_x; 128aa97efd9SGerrit Renker ktime_t now = stamp ? *stamp : ktime_get_real(); 1297c657876SArnaldo Carvalho de Melo 1300c150efbSGerrit Renker /* 1310c150efbSGerrit Renker * Handle IDLE periods: do not reduce below RFC3390 initial sending rate 132a5358fdcSGerrit Renker * when idling [RFC 4342, 5.1]. Definition of idling is from rfc3448bis: 133a5358fdcSGerrit Renker * a sender is idle if it has not sent anything over a 2-RTT-period. 1340c150efbSGerrit Renker * For consistency with X and X_recv, min_rate is also scaled by 2^6. 1350c150efbSGerrit Renker */ 136996ccf49SGerrit Renker if (ccid3_hc_tx_idle_rtt(hc, now) >= 2) { 1370c150efbSGerrit Renker min_rate = rfc3390_initial_rate(sk); 138996ccf49SGerrit Renker min_rate = max(min_rate, 2 * hc->tx_x_recv); 1390c150efbSGerrit Renker } 1400c150efbSGerrit Renker 141996ccf49SGerrit Renker if (hc->tx_p > 0) { 1421a21e49aSGerrit Renker 143996ccf49SGerrit Renker hc->tx_x = min(((__u64)hc->tx_x_calc) << 6, min_rate); 144996ccf49SGerrit Renker hc->tx_x = max(hc->tx_x, (((__u64)hc->tx_s) << 6) / TFRC_T_MBI); 145b6ee3d4aSArnaldo Carvalho de Melo 146996ccf49SGerrit Renker } else if (ktime_us_delta(now, hc->tx_t_ld) - (s64)hc->tx_rtt >= 0) { 1471a21e49aSGerrit Renker 148996ccf49SGerrit Renker hc->tx_x = min(2 * hc->tx_x, min_rate); 149996ccf49SGerrit Renker hc->tx_x = max(hc->tx_x, 150996ccf49SGerrit Renker scaled_div(((__u64)hc->tx_s) << 6, hc->tx_rtt)); 151996ccf49SGerrit Renker hc->tx_t_ld = now; 152ac198ea8SArnaldo Carvalho de Melo } 153a79ef76fSGerrit Renker 154996ccf49SGerrit Renker if (hc->tx_x != old_x) { 1551761f7d7SGerrit Renker ccid3_pr_debug("X_prev=%u, X_now=%u, X_calc=%u, " 1561761f7d7SGerrit Renker "X_recv=%u\n", (unsigned)(old_x >> 6), 157996ccf49SGerrit Renker (unsigned)(hc->tx_x >> 6), hc->tx_x_calc, 158996ccf49SGerrit Renker (unsigned)(hc->tx_x_recv >> 6)); 1598699be7dSIan McDonald 160996ccf49SGerrit Renker ccid3_update_send_interval(hc); 1617c657876SArnaldo Carvalho de Melo } 1628699be7dSIan McDonald } 1637c657876SArnaldo Carvalho de Melo 16478ad713dSGerrit Renker /* 165410e27a4SGerrit Renker * Track the mean packet size `s' (cf. RFC 4342, 5.3 and RFC 3448, 4.1) 166410e27a4SGerrit Renker * @len: DCCP packet payload size in bytes 16778ad713dSGerrit Renker */ 168996ccf49SGerrit Renker static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hc, int len) 16978ad713dSGerrit Renker { 170996ccf49SGerrit Renker const u16 old_s = hc->tx_s; 171410e27a4SGerrit Renker 172996ccf49SGerrit Renker hc->tx_s = tfrc_ewma(hc->tx_s, len, 9); 173410e27a4SGerrit Renker 174996ccf49SGerrit Renker if (hc->tx_s != old_s) 175996ccf49SGerrit Renker ccid3_update_send_interval(hc); 17678ad713dSGerrit Renker } 17778ad713dSGerrit Renker 1789f8681dbSGerrit Renker /* 1799f8681dbSGerrit Renker * Update Window Counter using the algorithm from [RFC 4342, 8.1]. 180825de27dSGerrit Renker * As elsewhere, RTT > 0 is assumed by using dccp_sample_rtt(). 1819f8681dbSGerrit Renker */ 182996ccf49SGerrit Renker static inline void ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock *hc, 1838132da4dSGerrit Renker ktime_t now) 1849f8681dbSGerrit Renker { 185996ccf49SGerrit Renker u32 delta = ktime_us_delta(now, hc->tx_t_last_win_count), 186996ccf49SGerrit Renker quarter_rtts = (4 * delta) / hc->tx_rtt; 1879f8681dbSGerrit Renker 1889f8681dbSGerrit Renker if (quarter_rtts > 0) { 189996ccf49SGerrit Renker hc->tx_t_last_win_count = now; 190996ccf49SGerrit Renker hc->tx_last_win_count += min(quarter_rtts, 5U); 191996ccf49SGerrit Renker hc->tx_last_win_count &= 0xF; /* mod 16 */ 1929f8681dbSGerrit Renker } 1939f8681dbSGerrit Renker } 1949f8681dbSGerrit Renker 1957c657876SArnaldo Carvalho de Melo static void ccid3_hc_tx_no_feedback_timer(unsigned long data) 1967c657876SArnaldo Carvalho de Melo { 1977c657876SArnaldo Carvalho de Melo struct sock *sk = (struct sock *)data; 198996ccf49SGerrit Renker struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); 1992a1fda6fSGerrit Renker unsigned long t_nfb = USEC_PER_SEC / 5; 2007c657876SArnaldo Carvalho de Melo 2017c657876SArnaldo Carvalho de Melo bh_lock_sock(sk); 2027c657876SArnaldo Carvalho de Melo if (sock_owned_by_user(sk)) { 2037c657876SArnaldo Carvalho de Melo /* Try again later. */ 2047c657876SArnaldo Carvalho de Melo /* XXX: set some sensible MIB */ 20548e03eeeSGerrit Renker goto restart_timer; 2067c657876SArnaldo Carvalho de Melo } 2077c657876SArnaldo Carvalho de Melo 208410e27a4SGerrit Renker ccid3_pr_debug("%s(%p, state=%s) - entry\n", dccp_role(sk), sk, 209996ccf49SGerrit Renker ccid3_tx_state_name(hc->tx_state)); 2107c657876SArnaldo Carvalho de Melo 211996ccf49SGerrit Renker if (hc->tx_state == TFRC_SSTATE_FBACK) 212410e27a4SGerrit Renker ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK); 213996ccf49SGerrit Renker else if (hc->tx_state != TFRC_SSTATE_NO_FBACK) 214d0995e6aSGerrit Renker goto out; 215d0995e6aSGerrit Renker 21652515e77SGerrit Renker /* 21752515e77SGerrit Renker * Determine new allowed sending rate X as per draft rfc3448bis-00, 4.4 21867b67e36SGerrit Renker * RTO is 0 if and only if no feedback has been received yet. 21952515e77SGerrit Renker */ 22067b67e36SGerrit Renker if (hc->tx_t_rto == 0 || hc->tx_p == 0) { 22152515e77SGerrit Renker 22252515e77SGerrit Renker /* halve send rate directly */ 223996ccf49SGerrit Renker hc->tx_x = max(hc->tx_x / 2, 224996ccf49SGerrit Renker (((__u64)hc->tx_s) << 6) / TFRC_T_MBI); 225996ccf49SGerrit Renker ccid3_update_send_interval(hc); 22652515e77SGerrit Renker } else { 2271f2333aeSArnaldo Carvalho de Melo /* 22852515e77SGerrit Renker * Modify the cached value of X_recv 229ff586298SGerrit Renker * 23052515e77SGerrit Renker * If (X_calc > 2 * X_recv) 2317c657876SArnaldo Carvalho de Melo * X_recv = max(X_recv / 2, s / (2 * t_mbi)); 2327c657876SArnaldo Carvalho de Melo * Else 2337c657876SArnaldo Carvalho de Melo * X_recv = X_calc / 4; 2341a21e49aSGerrit Renker * 2351a21e49aSGerrit Renker * Note that X_recv is scaled by 2^6 while X_calc is not 2367c657876SArnaldo Carvalho de Melo */ 237996ccf49SGerrit Renker BUG_ON(hc->tx_p && !hc->tx_x_calc); 2387c657876SArnaldo Carvalho de Melo 239996ccf49SGerrit Renker if (hc->tx_x_calc > (hc->tx_x_recv >> 5)) 240996ccf49SGerrit Renker hc->tx_x_recv = 241996ccf49SGerrit Renker max(hc->tx_x_recv / 2, 242996ccf49SGerrit Renker (((__u64)hc->tx_s) << 6) / (2*TFRC_T_MBI)); 24352515e77SGerrit Renker else { 244996ccf49SGerrit Renker hc->tx_x_recv = hc->tx_x_calc; 245996ccf49SGerrit Renker hc->tx_x_recv <<= 4; 2469e8efc82SGerrit Renker } 247aa97efd9SGerrit Renker ccid3_hc_tx_update_x(sk, NULL); 24852515e77SGerrit Renker } 24952515e77SGerrit Renker ccid3_pr_debug("Reduced X to %llu/64 bytes/sec\n", 250996ccf49SGerrit Renker (unsigned long long)hc->tx_x); 25152515e77SGerrit Renker 2526b5e633aSArnaldo Carvalho de Melo /* 25352515e77SGerrit Renker * Set new timeout for the nofeedback timer. 2548a508ac2SGerrit Renker * See comments in packet_recv() regarding the value of t_RTO. 2556b5e633aSArnaldo Carvalho de Melo */ 25667b67e36SGerrit Renker if (unlikely(hc->tx_t_rto == 0)) /* no feedback received yet */ 25752515e77SGerrit Renker t_nfb = TFRC_INITIAL_TIMEOUT; 25852515e77SGerrit Renker else 259996ccf49SGerrit Renker t_nfb = max(hc->tx_t_rto, 2 * hc->tx_t_ipi); 2607c657876SArnaldo Carvalho de Melo 26148e03eeeSGerrit Renker restart_timer: 262996ccf49SGerrit Renker sk_reset_timer(sk, &hc->tx_no_feedback_timer, 2632a1fda6fSGerrit Renker jiffies + usecs_to_jiffies(t_nfb)); 2647c657876SArnaldo Carvalho de Melo out: 2657c657876SArnaldo Carvalho de Melo bh_unlock_sock(sk); 2667c657876SArnaldo Carvalho de Melo sock_put(sk); 2677c657876SArnaldo Carvalho de Melo } 2687c657876SArnaldo Carvalho de Melo 269410e27a4SGerrit Renker /* 270410e27a4SGerrit Renker * returns 271410e27a4SGerrit Renker * > 0: delay (in msecs) that should pass before actually sending 272410e27a4SGerrit Renker * = 0: can send immediately 273410e27a4SGerrit Renker * < 0: error condition; do not send packet 2747da7f456SGerrit Renker */ 2756b57c93dSGerrit Renker static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb) 2767c657876SArnaldo Carvalho de Melo { 2777c657876SArnaldo Carvalho de Melo struct dccp_sock *dp = dccp_sk(sk); 278996ccf49SGerrit Renker struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); 2798132da4dSGerrit Renker ktime_t now = ktime_get_real(); 2808132da4dSGerrit Renker s64 delay; 2817c657876SArnaldo Carvalho de Melo 2827c657876SArnaldo Carvalho de Melo /* 283da335bafSGerrit Renker * This function is called only for Data and DataAck packets. Sending 284da335bafSGerrit Renker * zero-sized Data(Ack)s is theoretically possible, but for congestion 285da335bafSGerrit Renker * control this case is pathological - ignore it. 2867c657876SArnaldo Carvalho de Melo */ 2876b57c93dSGerrit Renker if (unlikely(skb->len == 0)) 288da335bafSGerrit Renker return -EBADMSG; 2897c657876SArnaldo Carvalho de Melo 290996ccf49SGerrit Renker switch (hc->tx_state) { 291410e27a4SGerrit Renker case TFRC_SSTATE_NO_SENT: 292996ccf49SGerrit Renker sk_reset_timer(sk, &hc->tx_no_feedback_timer, (jiffies + 2938109b02bSArnaldo Carvalho de Melo usecs_to_jiffies(TFRC_INITIAL_TIMEOUT))); 294996ccf49SGerrit Renker hc->tx_last_win_count = 0; 295996ccf49SGerrit Renker hc->tx_t_last_win_count = now; 29690feeb95SGerrit Renker 29790feeb95SGerrit Renker /* Set t_0 for initial packet */ 298996ccf49SGerrit Renker hc->tx_t_nom = now; 299410e27a4SGerrit Renker 300996ccf49SGerrit Renker hc->tx_s = skb->len; 30130833ffeSGerrit Renker 30230833ffeSGerrit Renker /* 30330833ffeSGerrit Renker * Use initial RTT sample when available: recommended by erratum 30430833ffeSGerrit Renker * to RFC 4342. This implements the initialisation procedure of 30530833ffeSGerrit Renker * draft rfc3448bis, section 4.2. Remember, X is scaled by 2^6. 30630833ffeSGerrit Renker */ 30730833ffeSGerrit Renker if (dp->dccps_syn_rtt) { 30830833ffeSGerrit Renker ccid3_pr_debug("SYN RTT = %uus\n", dp->dccps_syn_rtt); 309996ccf49SGerrit Renker hc->tx_rtt = dp->dccps_syn_rtt; 310996ccf49SGerrit Renker hc->tx_x = rfc3390_initial_rate(sk); 311996ccf49SGerrit Renker hc->tx_t_ld = now; 31230833ffeSGerrit Renker } else { 3133294f202SGerrit Renker /* 3143294f202SGerrit Renker * Sender does not have RTT sample: 3153294f202SGerrit Renker * - set fallback RTT (RFC 4340, 3.4) since a RTT value 3163294f202SGerrit Renker * is needed in several parts (e.g. window counter); 3173294f202SGerrit Renker * - set sending rate X_pps = 1pps as per RFC 3448, 4.2. 3183294f202SGerrit Renker */ 319996ccf49SGerrit Renker hc->tx_rtt = DCCP_FALLBACK_RTT; 320996ccf49SGerrit Renker hc->tx_x = hc->tx_s; 321996ccf49SGerrit Renker hc->tx_x <<= 6; 32230833ffeSGerrit Renker } 323996ccf49SGerrit Renker ccid3_update_send_interval(hc); 32430833ffeSGerrit Renker 325410e27a4SGerrit Renker ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK); 326410e27a4SGerrit Renker break; 327410e27a4SGerrit Renker case TFRC_SSTATE_NO_FBACK: 328410e27a4SGerrit Renker case TFRC_SSTATE_FBACK: 329996ccf49SGerrit Renker delay = ktime_us_delta(hc->tx_t_nom, now); 3308699be7dSIan McDonald ccid3_pr_debug("delay=%ld\n", (long)delay); 33191cf5a17SGerrit Renker /* 33220cbd3e1SGerrit Renker * Scheduling of packet transmissions (RFC 5348, 8.3) 33391cf5a17SGerrit Renker * 33491cf5a17SGerrit Renker * if (t_now > t_nom - delta) 33591cf5a17SGerrit Renker * // send the packet now 33691cf5a17SGerrit Renker * else 33791cf5a17SGerrit Renker * // send the packet in (t_nom - t_now) milliseconds. 33891cf5a17SGerrit Renker */ 33920cbd3e1SGerrit Renker if (delay >= TFRC_T_DELTA) 34020cbd3e1SGerrit Renker return (u32)delay / USEC_PER_MSEC; 3419f8681dbSGerrit Renker 342996ccf49SGerrit Renker ccid3_hc_tx_update_win_count(hc, now); 343410e27a4SGerrit Renker break; 344410e27a4SGerrit Renker case TFRC_SSTATE_TERM: 345410e27a4SGerrit Renker DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk); 346410e27a4SGerrit Renker return -EINVAL; 3477c657876SArnaldo Carvalho de Melo } 3487c657876SArnaldo Carvalho de Melo 3497da7f456SGerrit Renker /* prepare to send now (add options etc.) */ 350507d37cfSArnaldo Carvalho de Melo dp->dccps_hc_tx_insert_options = 1; 351996ccf49SGerrit Renker DCCP_SKB_CB(skb)->dccpd_ccval = hc->tx_last_win_count; 352e312d100SGerrit Renker 353e312d100SGerrit Renker /* set the nominal send time for the next following packet */ 354996ccf49SGerrit Renker hc->tx_t_nom = ktime_add_us(hc->tx_t_nom, hc->tx_t_ipi); 355410e27a4SGerrit Renker return 0; 3567c657876SArnaldo Carvalho de Melo } 3577c657876SArnaldo Carvalho de Melo 358410e27a4SGerrit Renker static void ccid3_hc_tx_packet_sent(struct sock *sk, int more, 359410e27a4SGerrit Renker unsigned int len) 3607c657876SArnaldo Carvalho de Melo { 361996ccf49SGerrit Renker struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); 3627c657876SArnaldo Carvalho de Melo 363996ccf49SGerrit Renker ccid3_hc_tx_update_s(hc, len); 36478ad713dSGerrit Renker 365996ccf49SGerrit Renker if (tfrc_tx_hist_add(&hc->tx_hist, dccp_sk(sk)->dccps_gss)) 366c5a1ae9aSGerrit Renker DCCP_CRIT("packet history - out of memory!"); 3677c657876SArnaldo Carvalho de Melo } 3687c657876SArnaldo Carvalho de Melo 3697c657876SArnaldo Carvalho de Melo static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) 3707c657876SArnaldo Carvalho de Melo { 371996ccf49SGerrit Renker struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); 37267b67e36SGerrit Renker struct ccid3_options_received *opt_recv = &hc->tx_options_received; 373d2c72630SGerrit Renker struct tfrc_tx_hist_entry *acked; 3740740d49cSArnaldo Carvalho de Melo ktime_t now; 3752a1fda6fSGerrit Renker unsigned long t_nfb; 376410e27a4SGerrit Renker u32 pinv, r_sample; 3771f2333aeSArnaldo Carvalho de Melo 3787c657876SArnaldo Carvalho de Melo /* we are only interested in ACKs */ 3797c657876SArnaldo Carvalho de Melo if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK || 3807c657876SArnaldo Carvalho de Melo DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK)) 3817c657876SArnaldo Carvalho de Melo return; 382410e27a4SGerrit Renker /* ... and only in the established state */ 383996ccf49SGerrit Renker if (hc->tx_state != TFRC_SSTATE_FBACK && 384996ccf49SGerrit Renker hc->tx_state != TFRC_SSTATE_NO_FBACK) 3857c657876SArnaldo Carvalho de Melo return; 38663b3a73bSGerrit Renker 387d2c72630SGerrit Renker /* 388d2c72630SGerrit Renker * Locate the acknowledged packet in the TX history. 389d2c72630SGerrit Renker * 390d2c72630SGerrit Renker * Returning "entry not found" here can for instance happen when 391d2c72630SGerrit Renker * - the host has not sent out anything (e.g. a passive server), 392d2c72630SGerrit Renker * - the Ack is outdated (packet with higher Ack number was received), 393d2c72630SGerrit Renker * - it is a bogus Ack (for a packet not sent on this connection). 394d2c72630SGerrit Renker */ 395d2c72630SGerrit Renker acked = tfrc_tx_hist_find_entry(hc->tx_hist, dccp_hdr_ack_seq(skb)); 396d2c72630SGerrit Renker if (acked == NULL) 397410e27a4SGerrit Renker return; 398d2c72630SGerrit Renker /* For the sake of RTT sampling, ignore/remove all older entries */ 399d2c72630SGerrit Renker tfrc_tx_hist_purge(&acked->next); 400d2c72630SGerrit Renker 401d2c72630SGerrit Renker /* Update the moving average for the RTT estimate (RFC 3448, 4.3) */ 402d2c72630SGerrit Renker now = ktime_get_real(); 403d2c72630SGerrit Renker r_sample = dccp_sample_rtt(sk, ktime_us_delta(now, acked->stamp)); 404d2c72630SGerrit Renker hc->tx_rtt = tfrc_ewma(hc->tx_rtt, r_sample, 9); 405410e27a4SGerrit Renker 406410e27a4SGerrit Renker /* Update receive rate in units of 64 * bytes/second */ 407996ccf49SGerrit Renker hc->tx_x_recv = opt_recv->ccid3or_receive_rate; 408996ccf49SGerrit Renker hc->tx_x_recv <<= 6; 409410e27a4SGerrit Renker 410410e27a4SGerrit Renker /* Update loss event rate (which is scaled by 1e6) */ 411410e27a4SGerrit Renker pinv = opt_recv->ccid3or_loss_event_rate; 412410e27a4SGerrit Renker if (pinv == ~0U || pinv == 0) /* see RFC 4342, 8.5 */ 413996ccf49SGerrit Renker hc->tx_p = 0; 414410e27a4SGerrit Renker else /* can not exceed 100% */ 415996ccf49SGerrit Renker hc->tx_p = scaled_div(1, pinv); 416d2c72630SGerrit Renker 4171a21e49aSGerrit Renker /* 418d8d1252fSGerrit Renker * Update allowed sending rate X as per draft rfc3448bis-00, 4.2/3 419d8d1252fSGerrit Renker */ 420996ccf49SGerrit Renker if (hc->tx_state == TFRC_SSTATE_NO_FBACK) { 421410e27a4SGerrit Renker ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK); 422d8d1252fSGerrit Renker 423996ccf49SGerrit Renker if (hc->tx_t_rto == 0) { 424d8d1252fSGerrit Renker /* 425d8d1252fSGerrit Renker * Initial feedback packet: Larger Initial Windows (4.2) 4261a21e49aSGerrit Renker */ 427996ccf49SGerrit Renker hc->tx_x = rfc3390_initial_rate(sk); 428996ccf49SGerrit Renker hc->tx_t_ld = now; 429a79ef76fSGerrit Renker 430996ccf49SGerrit Renker ccid3_update_send_interval(hc); 4315c3fbb6aSGerrit Renker 432d8d1252fSGerrit Renker goto done_computing_x; 433996ccf49SGerrit Renker } else if (hc->tx_p == 0) { 434d8d1252fSGerrit Renker /* 435d8d1252fSGerrit Renker * First feedback after nofeedback timer expiry (4.3) 436d8d1252fSGerrit Renker */ 437d8d1252fSGerrit Renker goto done_computing_x; 438d8d1252fSGerrit Renker } 439d8d1252fSGerrit Renker } 4405c3fbb6aSGerrit Renker 441ff586298SGerrit Renker /* Update sending rate (step 4 of [RFC 3448, 4.3]) */ 442996ccf49SGerrit Renker if (hc->tx_p > 0) 443996ccf49SGerrit Renker hc->tx_x_calc = tfrc_calc_x(hc->tx_s, hc->tx_rtt, hc->tx_p); 444aa97efd9SGerrit Renker ccid3_hc_tx_update_x(sk, &now); 4457c657876SArnaldo Carvalho de Melo 446d8d1252fSGerrit Renker done_computing_x: 4477dfee1a9SGerrit Renker ccid3_pr_debug("%s(%p), RTT=%uus (sample=%uus), s=%u, " 4488109b02bSArnaldo Carvalho de Melo "p=%u, X_calc=%u, X_recv=%u, X=%u\n", 449996ccf49SGerrit Renker dccp_role(sk), sk, hc->tx_rtt, r_sample, 450996ccf49SGerrit Renker hc->tx_s, hc->tx_p, hc->tx_x_calc, 451996ccf49SGerrit Renker (unsigned)(hc->tx_x_recv >> 6), 452996ccf49SGerrit Renker (unsigned)(hc->tx_x >> 6)); 4537c657876SArnaldo Carvalho de Melo 4547c657876SArnaldo Carvalho de Melo /* unschedule no feedback timer */ 455996ccf49SGerrit Renker sk_stop_timer(sk, &hc->tx_no_feedback_timer); 4567c657876SArnaldo Carvalho de Melo 457c530cfb1SArnaldo Carvalho de Melo /* 4588109b02bSArnaldo Carvalho de Melo * As we have calculated new ipi, delta, t_nom it is possible 4598109b02bSArnaldo Carvalho de Melo * that we now can send a packet, so wake up dccp_wait_for_ccid 460c530cfb1SArnaldo Carvalho de Melo */ 461c530cfb1SArnaldo Carvalho de Melo sk->sk_write_space(sk); 4628c60f3faSArnaldo Carvalho de Melo 4638a508ac2SGerrit Renker /* 46489858ad1SGerrit Renker * Update timeout interval for the nofeedback timer. In order to control 46589858ad1SGerrit Renker * rate halving on networks with very low RTTs (<= 1 ms), use per-route 46689858ad1SGerrit Renker * tunable RTAX_RTO_MIN value as the lower bound. 4678a508ac2SGerrit Renker */ 46889858ad1SGerrit Renker hc->tx_t_rto = max_t(u32, 4 * hc->tx_rtt, 46989858ad1SGerrit Renker USEC_PER_SEC/HZ * tcp_rto_min(sk)); 4701f2333aeSArnaldo Carvalho de Melo /* 4711f2333aeSArnaldo Carvalho de Melo * Schedule no feedback timer to expire in 4728a508ac2SGerrit Renker * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi) 4731f2333aeSArnaldo Carvalho de Melo */ 474996ccf49SGerrit Renker t_nfb = max(hc->tx_t_rto, 2 * hc->tx_t_ipi); 4757c657876SArnaldo Carvalho de Melo 476a9672411SGerrit Renker ccid3_pr_debug("%s(%p), Scheduled no feedback timer to " 4778109b02bSArnaldo Carvalho de Melo "expire in %lu jiffies (%luus)\n", 478388d5e99SGerrit Renker dccp_role(sk), sk, usecs_to_jiffies(t_nfb), t_nfb); 4797c657876SArnaldo Carvalho de Melo 480996ccf49SGerrit Renker sk_reset_timer(sk, &hc->tx_no_feedback_timer, 4812a1fda6fSGerrit Renker jiffies + usecs_to_jiffies(t_nfb)); 4827c657876SArnaldo Carvalho de Melo } 4837c657876SArnaldo Carvalho de Melo 484410e27a4SGerrit Renker static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option, 485410e27a4SGerrit Renker unsigned char len, u16 idx, 486410e27a4SGerrit Renker unsigned char *value) 4877c657876SArnaldo Carvalho de Melo { 488996ccf49SGerrit Renker struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); 48967b67e36SGerrit Renker struct ccid3_options_received *opt_recv = &hc->tx_options_received; 49076fd1e87SGerrit Renker __be32 opt_val; 4917c657876SArnaldo Carvalho de Melo 4927c657876SArnaldo Carvalho de Melo switch (option) { 49337efb03fSGerrit Renker case TFRC_OPT_RECEIVE_RATE: 4947c657876SArnaldo Carvalho de Melo case TFRC_OPT_LOSS_EVENT_RATE: 495410e27a4SGerrit Renker if (unlikely(len != 4)) { 49637efb03fSGerrit Renker DCCP_WARN("%s(%p), invalid len %d for %u\n", 49737efb03fSGerrit Renker dccp_role(sk), sk, len, option); 49837efb03fSGerrit Renker return -EINVAL; 49947a61e7bSGerrit Renker } 50037efb03fSGerrit Renker opt_val = ntohl(get_unaligned((__be32 *)value)); 501410e27a4SGerrit Renker 50237efb03fSGerrit Renker if (option == TFRC_OPT_RECEIVE_RATE) { 50337efb03fSGerrit Renker opt_recv->ccid3or_receive_rate = opt_val; 50437efb03fSGerrit Renker ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n", 50537efb03fSGerrit Renker dccp_role(sk), sk, opt_val); 50637efb03fSGerrit Renker } else { 50737efb03fSGerrit Renker opt_recv->ccid3or_loss_event_rate = opt_val; 50837efb03fSGerrit Renker ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n", 50937efb03fSGerrit Renker dccp_role(sk), sk, opt_val); 51037efb03fSGerrit Renker } 51137efb03fSGerrit Renker } 51237efb03fSGerrit Renker return 0; 5137c657876SArnaldo Carvalho de Melo } 5147c657876SArnaldo Carvalho de Melo 51591f0ebf7SArnaldo Carvalho de Melo static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk) 5167c657876SArnaldo Carvalho de Melo { 517996ccf49SGerrit Renker struct ccid3_hc_tx_sock *hc = ccid_priv(ccid); 5187c657876SArnaldo Carvalho de Melo 519996ccf49SGerrit Renker hc->tx_state = TFRC_SSTATE_NO_SENT; 520996ccf49SGerrit Renker hc->tx_hist = NULL; 521996ccf49SGerrit Renker setup_timer(&hc->tx_no_feedback_timer, 522b24b8a24SPavel Emelyanov ccid3_hc_tx_no_feedback_timer, (unsigned long)sk); 5237c657876SArnaldo Carvalho de Melo return 0; 5247c657876SArnaldo Carvalho de Melo } 5257c657876SArnaldo Carvalho de Melo 5267c657876SArnaldo Carvalho de Melo static void ccid3_hc_tx_exit(struct sock *sk) 5277c657876SArnaldo Carvalho de Melo { 528996ccf49SGerrit Renker struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); 5297c657876SArnaldo Carvalho de Melo 530410e27a4SGerrit Renker ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM); 531996ccf49SGerrit Renker sk_stop_timer(sk, &hc->tx_no_feedback_timer); 532410e27a4SGerrit Renker 533996ccf49SGerrit Renker tfrc_tx_hist_purge(&hc->tx_hist); 5347c657876SArnaldo Carvalho de Melo } 5357c657876SArnaldo Carvalho de Melo 5369bf17475SGerrit Renker static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info) 5379bf17475SGerrit Renker { 53851c22bb5SGerrit Renker info->tcpi_rto = ccid3_hc_tx_sk(sk)->tx_t_rto; 53951c22bb5SGerrit Renker info->tcpi_rtt = ccid3_hc_tx_sk(sk)->tx_rtt; 5409bf17475SGerrit Renker } 5419bf17475SGerrit Renker 5429bf17475SGerrit Renker static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len, 5439bf17475SGerrit Renker u32 __user *optval, int __user *optlen) 5449bf17475SGerrit Renker { 54551c22bb5SGerrit Renker const struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk); 54667b67e36SGerrit Renker struct tfrc_tx_info tfrc; 5479bf17475SGerrit Renker const void *val; 5489bf17475SGerrit Renker 5499bf17475SGerrit Renker switch (optname) { 5509bf17475SGerrit Renker case DCCP_SOCKOPT_CCID_TX_INFO: 55167b67e36SGerrit Renker if (len < sizeof(tfrc)) 5529bf17475SGerrit Renker return -EINVAL; 55367b67e36SGerrit Renker tfrc.tfrctx_x = hc->tx_x; 55467b67e36SGerrit Renker tfrc.tfrctx_x_recv = hc->tx_x_recv; 55567b67e36SGerrit Renker tfrc.tfrctx_x_calc = hc->tx_x_calc; 55667b67e36SGerrit Renker tfrc.tfrctx_rtt = hc->tx_rtt; 55767b67e36SGerrit Renker tfrc.tfrctx_p = hc->tx_p; 55867b67e36SGerrit Renker tfrc.tfrctx_rto = hc->tx_t_rto; 55967b67e36SGerrit Renker tfrc.tfrctx_ipi = hc->tx_t_ipi; 56067b67e36SGerrit Renker len = sizeof(tfrc); 56167b67e36SGerrit Renker val = &tfrc; 5629bf17475SGerrit Renker break; 5639bf17475SGerrit Renker default: 5649bf17475SGerrit Renker return -ENOPROTOOPT; 5659bf17475SGerrit Renker } 5669bf17475SGerrit Renker 5679bf17475SGerrit Renker if (put_user(len, optlen) || copy_to_user(optval, val, len)) 5689bf17475SGerrit Renker return -EFAULT; 5699bf17475SGerrit Renker 5709bf17475SGerrit Renker return 0; 5719bf17475SGerrit Renker } 5729bf17475SGerrit Renker 5739bf17475SGerrit Renker /* 5749bf17475SGerrit Renker * Receiver Half-Connection Routines 5759bf17475SGerrit Renker */ 576410e27a4SGerrit Renker 577410e27a4SGerrit Renker /* CCID3 feedback types */ 578410e27a4SGerrit Renker enum ccid3_fback_type { 579410e27a4SGerrit Renker CCID3_FBACK_NONE = 0, 580410e27a4SGerrit Renker CCID3_FBACK_INITIAL, 581410e27a4SGerrit Renker CCID3_FBACK_PERIODIC, 582410e27a4SGerrit Renker CCID3_FBACK_PARAM_CHANGE 583410e27a4SGerrit Renker }; 584410e27a4SGerrit Renker 585410e27a4SGerrit Renker #ifdef CONFIG_IP_DCCP_CCID3_DEBUG 586410e27a4SGerrit Renker static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state) 587410e27a4SGerrit Renker { 58836cbd3dcSJan Engelhardt static const char *const ccid3_rx_state_names[] = { 589410e27a4SGerrit Renker [TFRC_RSTATE_NO_DATA] = "NO_DATA", 590410e27a4SGerrit Renker [TFRC_RSTATE_DATA] = "DATA", 591410e27a4SGerrit Renker [TFRC_RSTATE_TERM] = "TERM", 592410e27a4SGerrit Renker }; 593410e27a4SGerrit Renker 594410e27a4SGerrit Renker return ccid3_rx_state_names[state]; 595410e27a4SGerrit Renker } 596410e27a4SGerrit Renker #endif 597410e27a4SGerrit Renker 598410e27a4SGerrit Renker static void ccid3_hc_rx_set_state(struct sock *sk, 599410e27a4SGerrit Renker enum ccid3_hc_rx_states state) 600410e27a4SGerrit Renker { 601996ccf49SGerrit Renker struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk); 602996ccf49SGerrit Renker enum ccid3_hc_rx_states oldstate = hc->rx_state; 603410e27a4SGerrit Renker 604410e27a4SGerrit Renker ccid3_pr_debug("%s(%p) %-8.8s -> %s\n", 605410e27a4SGerrit Renker dccp_role(sk), sk, ccid3_rx_state_name(oldstate), 606410e27a4SGerrit Renker ccid3_rx_state_name(state)); 607410e27a4SGerrit Renker WARN_ON(state == oldstate); 608996ccf49SGerrit Renker hc->rx_state = state; 609410e27a4SGerrit Renker } 610410e27a4SGerrit Renker 611b84a2189SArnaldo Carvalho de Melo static void ccid3_hc_rx_send_feedback(struct sock *sk, 612b84a2189SArnaldo Carvalho de Melo const struct sk_buff *skb, 613b84a2189SArnaldo Carvalho de Melo enum ccid3_fback_type fbtype) 6147c657876SArnaldo Carvalho de Melo { 615996ccf49SGerrit Renker struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk); 616410e27a4SGerrit Renker struct dccp_sock *dp = dccp_sk(sk); 617410e27a4SGerrit Renker ktime_t now; 618410e27a4SGerrit Renker s64 delta = 0; 619410e27a4SGerrit Renker 620996ccf49SGerrit Renker if (unlikely(hc->rx_state == TFRC_RSTATE_TERM)) 621410e27a4SGerrit Renker return; 622410e27a4SGerrit Renker 623410e27a4SGerrit Renker now = ktime_get_real(); 6247c657876SArnaldo Carvalho de Melo 625b84a2189SArnaldo Carvalho de Melo switch (fbtype) { 626b84a2189SArnaldo Carvalho de Melo case CCID3_FBACK_INITIAL: 627996ccf49SGerrit Renker hc->rx_x_recv = 0; 628996ccf49SGerrit Renker hc->rx_pinv = ~0U; /* see RFC 4342, 8.5 */ 6297c657876SArnaldo Carvalho de Melo break; 630b84a2189SArnaldo Carvalho de Melo case CCID3_FBACK_PARAM_CHANGE: 631b84a2189SArnaldo Carvalho de Melo /* 632b84a2189SArnaldo Carvalho de Melo * When parameters change (new loss or p > p_prev), we do not 633b84a2189SArnaldo Carvalho de Melo * have a reliable estimate for R_m of [RFC 3448, 6.2] and so 634410e27a4SGerrit Renker * need to reuse the previous value of X_recv. However, when 635410e27a4SGerrit Renker * X_recv was 0 (due to early loss), this would kill X down to 636410e27a4SGerrit Renker * s/t_mbi (i.e. one packet in 64 seconds). 637410e27a4SGerrit Renker * To avoid such drastic reduction, we approximate X_recv as 638410e27a4SGerrit Renker * the number of bytes since last feedback. 639410e27a4SGerrit Renker * This is a safe fallback, since X is bounded above by X_calc. 640b84a2189SArnaldo Carvalho de Melo */ 641996ccf49SGerrit Renker if (hc->rx_x_recv > 0) 642b84a2189SArnaldo Carvalho de Melo break; 643410e27a4SGerrit Renker /* fall through */ 644b84a2189SArnaldo Carvalho de Melo case CCID3_FBACK_PERIODIC: 645996ccf49SGerrit Renker delta = ktime_us_delta(now, hc->rx_tstamp_last_feedback); 646410e27a4SGerrit Renker if (delta <= 0) 647410e27a4SGerrit Renker DCCP_BUG("delta (%ld) <= 0", (long)delta); 648410e27a4SGerrit Renker else 649996ccf49SGerrit Renker hc->rx_x_recv = scaled_div32(hc->rx_bytes_recv, delta); 6507c657876SArnaldo Carvalho de Melo break; 651b84a2189SArnaldo Carvalho de Melo default: 6527c657876SArnaldo Carvalho de Melo return; 6537c657876SArnaldo Carvalho de Melo } 6547c657876SArnaldo Carvalho de Melo 655410e27a4SGerrit Renker ccid3_pr_debug("Interval %ldusec, X_recv=%u, 1/p=%u\n", (long)delta, 656996ccf49SGerrit Renker hc->rx_x_recv, hc->rx_pinv); 6577c657876SArnaldo Carvalho de Melo 658996ccf49SGerrit Renker hc->rx_tstamp_last_feedback = now; 659996ccf49SGerrit Renker hc->rx_last_counter = dccp_hdr(skb)->dccph_ccval; 660996ccf49SGerrit Renker hc->rx_bytes_recv = 0; 661410e27a4SGerrit Renker 662410e27a4SGerrit Renker dp->dccps_hc_rx_insert_options = 1; 6637c657876SArnaldo Carvalho de Melo dccp_send_ack(sk); 6647c657876SArnaldo Carvalho de Melo } 6657c657876SArnaldo Carvalho de Melo 6662d0817d1SArnaldo Carvalho de Melo static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb) 6677c657876SArnaldo Carvalho de Melo { 66851c22bb5SGerrit Renker const struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk); 66960fe62e7SAndrea Bittau __be32 x_recv, pinv; 6707c657876SArnaldo Carvalho de Melo 67159d203f9SArnaldo Carvalho de Melo if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN)) 6722d0817d1SArnaldo Carvalho de Melo return 0; 6737c657876SArnaldo Carvalho de Melo 6744fded33bSArnaldo Carvalho de Melo if (dccp_packet_without_ack(skb)) 6752d0817d1SArnaldo Carvalho de Melo return 0; 6764fded33bSArnaldo Carvalho de Melo 677996ccf49SGerrit Renker x_recv = htonl(hc->rx_x_recv); 678996ccf49SGerrit Renker pinv = htonl(hc->rx_pinv); 6792d0817d1SArnaldo Carvalho de Melo 680a7d13fbfSGerrit Renker if (dccp_insert_option(skb, TFRC_OPT_LOSS_EVENT_RATE, 6812d0817d1SArnaldo Carvalho de Melo &pinv, sizeof(pinv)) || 682a7d13fbfSGerrit Renker dccp_insert_option(skb, TFRC_OPT_RECEIVE_RATE, 6832d0817d1SArnaldo Carvalho de Melo &x_recv, sizeof(x_recv))) 6842d0817d1SArnaldo Carvalho de Melo return -1; 6852d0817d1SArnaldo Carvalho de Melo 6862d0817d1SArnaldo Carvalho de Melo return 0; 6877c657876SArnaldo Carvalho de Melo } 6887c657876SArnaldo Carvalho de Melo 689aa1b1ff0SGerrit Renker /** 690aa1b1ff0SGerrit Renker * ccid3_first_li - Implements [RFC 5348, 6.3.1] 691954c2db8SGerrit Renker * 692954c2db8SGerrit Renker * Determine the length of the first loss interval via inverse lookup. 693954c2db8SGerrit Renker * Assume that X_recv can be computed by the throughput equation 694954c2db8SGerrit Renker * s 695954c2db8SGerrit Renker * X_recv = -------- 696954c2db8SGerrit Renker * R * fval 697954c2db8SGerrit Renker * Find some p such that f(p) = fval; return 1/p (scaled). 698954c2db8SGerrit Renker */ 699954c2db8SGerrit Renker static u32 ccid3_first_li(struct sock *sk) 700954c2db8SGerrit Renker { 701996ccf49SGerrit Renker struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk); 702410e27a4SGerrit Renker u32 x_recv, p, delta; 703954c2db8SGerrit Renker u64 fval; 704954c2db8SGerrit Renker 705996ccf49SGerrit Renker if (hc->rx_rtt == 0) { 706410e27a4SGerrit Renker DCCP_WARN("No RTT estimate available, using fallback RTT\n"); 707996ccf49SGerrit Renker hc->rx_rtt = DCCP_FALLBACK_RTT; 708410e27a4SGerrit Renker } 709d20ed95fSGerrit Renker 710996ccf49SGerrit Renker delta = ktime_to_us(net_timedelta(hc->rx_tstamp_last_feedback)); 711996ccf49SGerrit Renker x_recv = scaled_div32(hc->rx_bytes_recv, delta); 712410e27a4SGerrit Renker if (x_recv == 0) { /* would also trigger divide-by-zero */ 713410e27a4SGerrit Renker DCCP_WARN("X_recv==0\n"); 71467b67e36SGerrit Renker if (hc->rx_x_recv == 0) { 715410e27a4SGerrit Renker DCCP_BUG("stored value of X_recv is zero"); 716410e27a4SGerrit Renker return ~0U; 717410e27a4SGerrit Renker } 71867b67e36SGerrit Renker x_recv = hc->rx_x_recv; 719410e27a4SGerrit Renker } 720954c2db8SGerrit Renker 721996ccf49SGerrit Renker fval = scaled_div(hc->rx_s, hc->rx_rtt); 722410e27a4SGerrit Renker fval = scaled_div32(fval, x_recv); 723954c2db8SGerrit Renker p = tfrc_calc_x_reverse_lookup(fval); 724954c2db8SGerrit Renker 725954c2db8SGerrit Renker ccid3_pr_debug("%s(%p), receive rate=%u bytes/s, implied " 726954c2db8SGerrit Renker "loss rate=%u\n", dccp_role(sk), sk, x_recv, p); 727954c2db8SGerrit Renker 728410e27a4SGerrit Renker return p == 0 ? ~0U : scaled_div(1, p); 729954c2db8SGerrit Renker } 730954c2db8SGerrit Renker 7317c657876SArnaldo Carvalho de Melo static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) 7327c657876SArnaldo Carvalho de Melo { 733996ccf49SGerrit Renker struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk); 734410e27a4SGerrit Renker enum ccid3_fback_type do_feedback = CCID3_FBACK_NONE; 7355b5d0e70SGerrit Renker const u64 ndp = dccp_sk(sk)->dccps_options_received.dccpor_ndp; 736b84a2189SArnaldo Carvalho de Melo const bool is_data_packet = dccp_data_packet(skb); 7371f2333aeSArnaldo Carvalho de Melo 738996ccf49SGerrit Renker if (unlikely(hc->rx_state == TFRC_RSTATE_NO_DATA)) { 739410e27a4SGerrit Renker if (is_data_packet) { 740410e27a4SGerrit Renker const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4; 741410e27a4SGerrit Renker do_feedback = CCID3_FBACK_INITIAL; 742410e27a4SGerrit Renker ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA); 743996ccf49SGerrit Renker hc->rx_s = payload; 744410e27a4SGerrit Renker /* 745388d5e99SGerrit Renker * Not necessary to update rx_bytes_recv here, 746410e27a4SGerrit Renker * since X_recv = 0 for the first feedback packet (cf. 747410e27a4SGerrit Renker * RFC 3448, 6.3) -- gerrit 748410e27a4SGerrit Renker */ 749410e27a4SGerrit Renker } 750410e27a4SGerrit Renker goto update_records; 751410e27a4SGerrit Renker } 752410e27a4SGerrit Renker 753996ccf49SGerrit Renker if (tfrc_rx_hist_duplicate(&hc->rx_hist, skb)) 754410e27a4SGerrit Renker return; /* done receiving */ 755410e27a4SGerrit Renker 756410e27a4SGerrit Renker if (is_data_packet) { 757410e27a4SGerrit Renker const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4; 758410e27a4SGerrit Renker /* 759410e27a4SGerrit Renker * Update moving-average of s and the sum of received payload bytes 760410e27a4SGerrit Renker */ 761996ccf49SGerrit Renker hc->rx_s = tfrc_ewma(hc->rx_s, payload, 9); 762996ccf49SGerrit Renker hc->rx_bytes_recv += payload; 763410e27a4SGerrit Renker } 764410e27a4SGerrit Renker 765d20ed95fSGerrit Renker /* 766d20ed95fSGerrit Renker * Perform loss detection and handle pending losses 767d20ed95fSGerrit Renker */ 768996ccf49SGerrit Renker if (tfrc_rx_handle_loss(&hc->rx_hist, &hc->rx_li_hist, 769410e27a4SGerrit Renker skb, ndp, ccid3_first_li, sk)) { 770410e27a4SGerrit Renker do_feedback = CCID3_FBACK_PARAM_CHANGE; 771410e27a4SGerrit Renker goto done_receiving; 772410e27a4SGerrit Renker } 773410e27a4SGerrit Renker 774996ccf49SGerrit Renker if (tfrc_rx_hist_loss_pending(&hc->rx_hist)) 775410e27a4SGerrit Renker return; /* done receiving */ 776410e27a4SGerrit Renker 77788e97a93SGerrit Renker /* 778410e27a4SGerrit Renker * Handle data packets: RTT sampling and monitoring p 77988e97a93SGerrit Renker */ 780410e27a4SGerrit Renker if (unlikely(!is_data_packet)) 781410e27a4SGerrit Renker goto update_records; 782410e27a4SGerrit Renker 783996ccf49SGerrit Renker if (!tfrc_lh_is_initialised(&hc->rx_li_hist)) { 784996ccf49SGerrit Renker const u32 sample = tfrc_rx_hist_sample_rtt(&hc->rx_hist, skb); 785410e27a4SGerrit Renker /* 786410e27a4SGerrit Renker * Empty loss history: no loss so far, hence p stays 0. 787410e27a4SGerrit Renker * Sample RTT values, since an RTT estimate is required for the 788410e27a4SGerrit Renker * computation of p when the first loss occurs; RFC 3448, 6.3.1. 789410e27a4SGerrit Renker */ 790410e27a4SGerrit Renker if (sample != 0) 791996ccf49SGerrit Renker hc->rx_rtt = tfrc_ewma(hc->rx_rtt, sample, 9); 792410e27a4SGerrit Renker 793996ccf49SGerrit Renker } else if (tfrc_lh_update_i_mean(&hc->rx_li_hist, skb)) { 794410e27a4SGerrit Renker /* 795410e27a4SGerrit Renker * Step (3) of [RFC 3448, 6.1]: Recompute I_mean and, if I_mean 796410e27a4SGerrit Renker * has decreased (resp. p has increased), send feedback now. 797410e27a4SGerrit Renker */ 798410e27a4SGerrit Renker do_feedback = CCID3_FBACK_PARAM_CHANGE; 799410e27a4SGerrit Renker } 800410e27a4SGerrit Renker 801b84a2189SArnaldo Carvalho de Melo /* 802b84a2189SArnaldo Carvalho de Melo * Check if the periodic once-per-RTT feedback is due; RFC 4342, 10.3 803b84a2189SArnaldo Carvalho de Melo */ 804996ccf49SGerrit Renker if (SUB16(dccp_hdr(skb)->dccph_ccval, hc->rx_last_counter) > 3) 805410e27a4SGerrit Renker do_feedback = CCID3_FBACK_PERIODIC; 806410e27a4SGerrit Renker 807410e27a4SGerrit Renker update_records: 808996ccf49SGerrit Renker tfrc_rx_hist_add_packet(&hc->rx_hist, skb, ndp); 809410e27a4SGerrit Renker 810410e27a4SGerrit Renker done_receiving: 811410e27a4SGerrit Renker if (do_feedback) 812410e27a4SGerrit Renker ccid3_hc_rx_send_feedback(sk, skb, do_feedback); 8137c657876SArnaldo Carvalho de Melo } 8147c657876SArnaldo Carvalho de Melo 81591f0ebf7SArnaldo Carvalho de Melo static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk) 8167c657876SArnaldo Carvalho de Melo { 817996ccf49SGerrit Renker struct ccid3_hc_rx_sock *hc = ccid_priv(ccid); 8187c657876SArnaldo Carvalho de Melo 819996ccf49SGerrit Renker hc->rx_state = TFRC_RSTATE_NO_DATA; 820996ccf49SGerrit Renker tfrc_lh_init(&hc->rx_li_hist); 821996ccf49SGerrit Renker return tfrc_rx_hist_alloc(&hc->rx_hist); 8227c657876SArnaldo Carvalho de Melo } 8237c657876SArnaldo Carvalho de Melo 8247c657876SArnaldo Carvalho de Melo static void ccid3_hc_rx_exit(struct sock *sk) 8257c657876SArnaldo Carvalho de Melo { 826996ccf49SGerrit Renker struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk); 8277c657876SArnaldo Carvalho de Melo 828410e27a4SGerrit Renker ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM); 829410e27a4SGerrit Renker 830996ccf49SGerrit Renker tfrc_rx_hist_purge(&hc->rx_hist); 831996ccf49SGerrit Renker tfrc_lh_cleanup(&hc->rx_li_hist); 8327c657876SArnaldo Carvalho de Melo } 8337c657876SArnaldo Carvalho de Melo 8342babe1f6SArnaldo Carvalho de Melo static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info) 8352babe1f6SArnaldo Carvalho de Melo { 83651c22bb5SGerrit Renker info->tcpi_ca_state = ccid3_hc_rx_sk(sk)->rx_state; 8372babe1f6SArnaldo Carvalho de Melo info->tcpi_options |= TCPI_OPT_TIMESTAMPS; 83851c22bb5SGerrit Renker info->tcpi_rcv_rtt = ccid3_hc_rx_sk(sk)->rx_rtt; 8392babe1f6SArnaldo Carvalho de Melo } 8402babe1f6SArnaldo Carvalho de Melo 84188f964dbSArnaldo Carvalho de Melo static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len, 84288f964dbSArnaldo Carvalho de Melo u32 __user *optval, int __user *optlen) 84388f964dbSArnaldo Carvalho de Melo { 84451c22bb5SGerrit Renker const struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk); 8458e138e79SGerrit Renker struct tfrc_rx_info rx_info; 84688f964dbSArnaldo Carvalho de Melo const void *val; 84788f964dbSArnaldo Carvalho de Melo 84888f964dbSArnaldo Carvalho de Melo switch (optname) { 84988f964dbSArnaldo Carvalho de Melo case DCCP_SOCKOPT_CCID_RX_INFO: 8508e138e79SGerrit Renker if (len < sizeof(rx_info)) 85188f964dbSArnaldo Carvalho de Melo return -EINVAL; 852996ccf49SGerrit Renker rx_info.tfrcrx_x_recv = hc->rx_x_recv; 853996ccf49SGerrit Renker rx_info.tfrcrx_rtt = hc->rx_rtt; 854996ccf49SGerrit Renker rx_info.tfrcrx_p = hc->rx_pinv == 0 ? ~0U : 855996ccf49SGerrit Renker scaled_div(1, hc->rx_pinv); 8568e138e79SGerrit Renker len = sizeof(rx_info); 8578e138e79SGerrit Renker val = &rx_info; 85888f964dbSArnaldo Carvalho de Melo break; 85988f964dbSArnaldo Carvalho de Melo default: 86088f964dbSArnaldo Carvalho de Melo return -ENOPROTOOPT; 86188f964dbSArnaldo Carvalho de Melo } 86288f964dbSArnaldo Carvalho de Melo 86388f964dbSArnaldo Carvalho de Melo if (put_user(len, optlen) || copy_to_user(optval, val, len)) 86488f964dbSArnaldo Carvalho de Melo return -EFAULT; 86588f964dbSArnaldo Carvalho de Melo 86688f964dbSArnaldo Carvalho de Melo return 0; 86788f964dbSArnaldo Carvalho de Melo } 86888f964dbSArnaldo Carvalho de Melo 869ddebc973SGerrit Renker struct ccid_operations ccid3_ops = { 8703dd9a7c3SIan McDonald .ccid_id = DCCPC_CCID3, 87184a97b0aSGerrit Renker .ccid_name = "TCP-Friendly Rate Control", 87291f0ebf7SArnaldo Carvalho de Melo .ccid_hc_tx_obj_size = sizeof(struct ccid3_hc_tx_sock), 8737c657876SArnaldo Carvalho de Melo .ccid_hc_tx_init = ccid3_hc_tx_init, 8747c657876SArnaldo Carvalho de Melo .ccid_hc_tx_exit = ccid3_hc_tx_exit, 8757c657876SArnaldo Carvalho de Melo .ccid_hc_tx_send_packet = ccid3_hc_tx_send_packet, 8767c657876SArnaldo Carvalho de Melo .ccid_hc_tx_packet_sent = ccid3_hc_tx_packet_sent, 8777c657876SArnaldo Carvalho de Melo .ccid_hc_tx_packet_recv = ccid3_hc_tx_packet_recv, 8787c657876SArnaldo Carvalho de Melo .ccid_hc_tx_parse_options = ccid3_hc_tx_parse_options, 87991f0ebf7SArnaldo Carvalho de Melo .ccid_hc_rx_obj_size = sizeof(struct ccid3_hc_rx_sock), 8807c657876SArnaldo Carvalho de Melo .ccid_hc_rx_init = ccid3_hc_rx_init, 8817c657876SArnaldo Carvalho de Melo .ccid_hc_rx_exit = ccid3_hc_rx_exit, 8827c657876SArnaldo Carvalho de Melo .ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options, 8837c657876SArnaldo Carvalho de Melo .ccid_hc_rx_packet_recv = ccid3_hc_rx_packet_recv, 8842babe1f6SArnaldo Carvalho de Melo .ccid_hc_rx_get_info = ccid3_hc_rx_get_info, 8852babe1f6SArnaldo Carvalho de Melo .ccid_hc_tx_get_info = ccid3_hc_tx_get_info, 88688f964dbSArnaldo Carvalho de Melo .ccid_hc_rx_getsockopt = ccid3_hc_rx_getsockopt, 88788f964dbSArnaldo Carvalho de Melo .ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt, 8887c657876SArnaldo Carvalho de Melo }; 8897c657876SArnaldo Carvalho de Melo 89056724aa4SGerrit Renker #ifdef CONFIG_IP_DCCP_CCID3_DEBUG 89143264991SGerrit Renker module_param(ccid3_debug, bool, 0644); 892ddebc973SGerrit Renker MODULE_PARM_DESC(ccid3_debug, "Enable CCID-3 debug messages"); 89356724aa4SGerrit Renker #endif 894