17c657876SArnaldo Carvalho de Melo /* 27c657876SArnaldo Carvalho de Melo * net/dccp/ccids/ccid3.c 37c657876SArnaldo Carvalho de Melo * 4954c2db8SGerrit Renker * Copyright (c) 2007 The University of Aberdeen, Scotland, UK 5b2f41ff4SIan McDonald * Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand. 6b2f41ff4SIan McDonald * Copyright (c) 2005-7 Ian McDonald <ian.mcdonald@jandi.co.nz> 77c657876SArnaldo Carvalho de Melo * 87c657876SArnaldo Carvalho de Melo * An implementation of the DCCP protocol 97c657876SArnaldo Carvalho de Melo * 107c657876SArnaldo Carvalho de Melo * This code has been developed by the University of Waikato WAND 117c657876SArnaldo Carvalho de Melo * research group. For further information please see http://www.wand.net.nz/ 127c657876SArnaldo Carvalho de Melo * 137c657876SArnaldo Carvalho de Melo * This code also uses code from Lulea University, rereleased as GPL by its 147c657876SArnaldo Carvalho de Melo * authors: 157c657876SArnaldo Carvalho de Melo * Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon 167c657876SArnaldo Carvalho de Melo * 177c657876SArnaldo Carvalho de Melo * Changes to meet Linux coding standards, to make it meet latest ccid3 draft 187c657876SArnaldo Carvalho de Melo * and to make it work as a loadable module in the DCCP stack written by 197c657876SArnaldo Carvalho de Melo * Arnaldo Carvalho de Melo <acme@conectiva.com.br>. 207c657876SArnaldo Carvalho de Melo * 217c657876SArnaldo Carvalho de Melo * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br> 227c657876SArnaldo Carvalho de Melo * 237c657876SArnaldo Carvalho de Melo * This program is free software; you can redistribute it and/or modify 247c657876SArnaldo Carvalho de Melo * it under the terms of the GNU General Public License as published by 257c657876SArnaldo Carvalho de Melo * the Free Software Foundation; either version 2 of the License, or 267c657876SArnaldo Carvalho de Melo * (at your option) any later version. 277c657876SArnaldo Carvalho de Melo * 287c657876SArnaldo Carvalho de Melo * This program is distributed in the hope that it will be useful, 297c657876SArnaldo Carvalho de Melo * but WITHOUT ANY WARRANTY; without even the implied warranty of 307c657876SArnaldo Carvalho de Melo * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 317c657876SArnaldo Carvalho de Melo * GNU General Public License for more details. 327c657876SArnaldo Carvalho de Melo * 337c657876SArnaldo Carvalho de Melo * You should have received a copy of the GNU General Public License 347c657876SArnaldo Carvalho de Melo * along with this program; if not, write to the Free Software 357c657876SArnaldo Carvalho de Melo * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 367c657876SArnaldo Carvalho de Melo */ 377c657876SArnaldo Carvalho de Melo #include "../dccp.h" 387c657876SArnaldo Carvalho de Melo #include "ccid3.h" 397c657876SArnaldo Carvalho de Melo 4076fd1e87SGerrit Renker #include <asm/unaligned.h> 4176fd1e87SGerrit Renker 4256724aa4SGerrit Renker #ifdef CONFIG_IP_DCCP_CCID3_DEBUG 4356724aa4SGerrit Renker static int ccid3_debug; 4456724aa4SGerrit Renker #define ccid3_pr_debug(format, a...) DCCP_PR_DEBUG(ccid3_debug, format, ##a) 457c657876SArnaldo Carvalho de Melo #else 467c657876SArnaldo Carvalho de Melo #define ccid3_pr_debug(format, a...) 477c657876SArnaldo Carvalho de Melo #endif 487c657876SArnaldo Carvalho de Melo 499bf17475SGerrit Renker /* 509bf17475SGerrit Renker * Transmitter Half-Connection Routines 519bf17475SGerrit Renker */ 5256724aa4SGerrit Renker #ifdef CONFIG_IP_DCCP_CCID3_DEBUG 537c657876SArnaldo Carvalho de Melo static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state) 547c657876SArnaldo Carvalho de Melo { 557c657876SArnaldo Carvalho de Melo static char *ccid3_state_names[] = { 567c657876SArnaldo Carvalho de Melo [TFRC_SSTATE_NO_SENT] = "NO_SENT", 577c657876SArnaldo Carvalho de Melo [TFRC_SSTATE_NO_FBACK] = "NO_FBACK", 587c657876SArnaldo Carvalho de Melo [TFRC_SSTATE_FBACK] = "FBACK", 597c657876SArnaldo Carvalho de Melo }; 607c657876SArnaldo Carvalho de Melo 617c657876SArnaldo Carvalho de Melo return ccid3_state_names[state]; 627c657876SArnaldo Carvalho de Melo } 637c657876SArnaldo Carvalho de Melo #endif 647c657876SArnaldo Carvalho de Melo 65c25a18baSArnaldo Carvalho de Melo static void ccid3_hc_tx_set_state(struct sock *sk, 661f2333aeSArnaldo Carvalho de Melo enum ccid3_hc_tx_states state) 677c657876SArnaldo Carvalho de Melo { 6859725dc2SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 69842d1ef1SGerrit Renker enum ccid3_hc_tx_states oldstate = hctx->state; 707c657876SArnaldo Carvalho de Melo 717c657876SArnaldo Carvalho de Melo ccid3_pr_debug("%s(%p) %-8.8s -> %s\n", 721f2333aeSArnaldo Carvalho de Melo dccp_role(sk), sk, ccid3_tx_state_name(oldstate), 731f2333aeSArnaldo Carvalho de Melo ccid3_tx_state_name(state)); 747c657876SArnaldo Carvalho de Melo WARN_ON(state == oldstate); 75842d1ef1SGerrit Renker hctx->state = state; 767c657876SArnaldo Carvalho de Melo } 777c657876SArnaldo Carvalho de Melo 7817893bc1SGerrit Renker /* 796c08b2cfSGerrit Renker * Compute the initial sending rate X_init in the manner of RFC 3390: 806c08b2cfSGerrit Renker * 816c08b2cfSGerrit Renker * X_init = min(4 * s, max(2 * s, 4380 bytes)) / RTT 826c08b2cfSGerrit Renker * 836c08b2cfSGerrit Renker * Note that RFC 3390 uses MSS, RFC 4342 refers to RFC 3390, and rfc3448bis 846c08b2cfSGerrit Renker * (rev-02) clarifies the use of RFC 3390 with regard to the above formula. 85a21f9f96SGerrit Renker * For consistency with other parts of the code, X_init is scaled by 2^6. 86a21f9f96SGerrit Renker */ 87a21f9f96SGerrit Renker static inline u64 rfc3390_initial_rate(struct sock *sk) 88a21f9f96SGerrit Renker { 896c08b2cfSGerrit Renker const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 90842d1ef1SGerrit Renker const __u32 w_init = clamp_t(__u32, 4380U, 2 * hctx->s, 4 * hctx->s); 91a21f9f96SGerrit Renker 92842d1ef1SGerrit Renker return scaled_div(w_init << 6, hctx->rtt); 93a21f9f96SGerrit Renker } 94a21f9f96SGerrit Renker 95de6f2b59SGerrit Renker /** 96de6f2b59SGerrit Renker * ccid3_update_send_interval - Calculate new t_ipi = s / X_inst 97de6f2b59SGerrit Renker * This respects the granularity of X_inst (64 * bytes/second). 9817893bc1SGerrit Renker */ 99c4e18dadSIlpo Järvinen static void ccid3_update_send_interval(struct ccid3_hc_tx_sock *hctx) 1007c657876SArnaldo Carvalho de Melo { 101842d1ef1SGerrit Renker hctx->t_ipi = scaled_div32(((u64)hctx->s) << 6, hctx->x); 10217893bc1SGerrit Renker 103de6f2b59SGerrit Renker ccid3_pr_debug("t_ipi=%u, s=%u, X=%u\n", hctx->t_ipi, 104de6f2b59SGerrit Renker hctx->s, (unsigned)(hctx->x >> 6)); 1057c657876SArnaldo Carvalho de Melo } 106aa97efd9SGerrit Renker 107a5358fdcSGerrit Renker static u32 ccid3_hc_tx_idle_rtt(struct ccid3_hc_tx_sock *hctx, ktime_t now) 108a5358fdcSGerrit Renker { 109842d1ef1SGerrit Renker u32 delta = ktime_us_delta(now, hctx->t_last_win_count); 110a5358fdcSGerrit Renker 111842d1ef1SGerrit Renker return delta / hctx->rtt; 112a5358fdcSGerrit Renker } 113a5358fdcSGerrit Renker 114aa97efd9SGerrit Renker /** 115aa97efd9SGerrit Renker * ccid3_hc_tx_update_x - Update allowed sending rate X 116aa97efd9SGerrit Renker * @stamp: most recent time if available - can be left NULL. 117aa97efd9SGerrit Renker * This function tracks draft rfc3448bis, check there for latest details. 1185c3fbb6aSGerrit Renker * 1191a21e49aSGerrit Renker * Note: X and X_recv are both stored in units of 64 * bytes/second, to support 1201a21e49aSGerrit Renker * fine-grained resolution of sending rates. This requires scaling by 2^6 1211a21e49aSGerrit Renker * throughout the code. Only X_calc is unscaled (in bytes/second). 1221a21e49aSGerrit Renker * 1237c657876SArnaldo Carvalho de Melo */ 124aa97efd9SGerrit Renker static void ccid3_hc_tx_update_x(struct sock *sk, ktime_t *stamp) 1257c657876SArnaldo Carvalho de Melo { 12659725dc2SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 127842d1ef1SGerrit Renker u64 min_rate = 2 * hctx->x_recv; 128842d1ef1SGerrit Renker const u64 old_x = hctx->x; 129aa97efd9SGerrit Renker ktime_t now = stamp ? *stamp : ktime_get_real(); 1307c657876SArnaldo Carvalho de Melo 1310c150efbSGerrit Renker /* 1320c150efbSGerrit Renker * Handle IDLE periods: do not reduce below RFC3390 initial sending rate 133a5358fdcSGerrit Renker * when idling [RFC 4342, 5.1]. Definition of idling is from rfc3448bis: 134a5358fdcSGerrit Renker * a sender is idle if it has not sent anything over a 2-RTT-period. 1350c150efbSGerrit Renker * For consistency with X and X_recv, min_rate is also scaled by 2^6. 1360c150efbSGerrit Renker */ 137a5358fdcSGerrit Renker if (ccid3_hc_tx_idle_rtt(hctx, now) >= 2) { 1380c150efbSGerrit Renker min_rate = rfc3390_initial_rate(sk); 139842d1ef1SGerrit Renker min_rate = max(min_rate, 2 * hctx->x_recv); 1400c150efbSGerrit Renker } 1410c150efbSGerrit Renker 142842d1ef1SGerrit Renker if (hctx->p > 0) { 1431a21e49aSGerrit Renker 144842d1ef1SGerrit Renker hctx->x = min(((u64)hctx->x_calc) << 6, min_rate); 145842d1ef1SGerrit Renker hctx->x = max(hctx->x, (((u64)hctx->s) << 6) / TFRC_T_MBI); 146b6ee3d4aSArnaldo Carvalho de Melo 147842d1ef1SGerrit Renker } else if (ktime_us_delta(now, hctx->t_ld) - (s64)hctx->rtt >= 0) { 1481a21e49aSGerrit Renker 149842d1ef1SGerrit Renker hctx->x = min(2 * hctx->x, min_rate); 150842d1ef1SGerrit Renker hctx->x = max(hctx->x, 151842d1ef1SGerrit Renker scaled_div(((u64)hctx->s) << 6, hctx->rtt)); 152842d1ef1SGerrit Renker hctx->t_ld = now; 153ac198ea8SArnaldo Carvalho de Melo } 154a79ef76fSGerrit Renker 155842d1ef1SGerrit Renker if (hctx->x != old_x) { 1561761f7d7SGerrit Renker ccid3_pr_debug("X_prev=%u, X_now=%u, X_calc=%u, " 1571761f7d7SGerrit Renker "X_recv=%u\n", (unsigned)(old_x >> 6), 158842d1ef1SGerrit Renker (unsigned)(hctx->x >> 6), hctx->x_calc, 159842d1ef1SGerrit Renker (unsigned)(hctx->x_recv >> 6)); 1608699be7dSIan McDonald 1611266adeeSGerrit Renker ccid3_update_send_interval(hctx); 1627c657876SArnaldo Carvalho de Melo } 1638699be7dSIan McDonald } 1647c657876SArnaldo Carvalho de Melo 16578ad713dSGerrit Renker /* 16678ad713dSGerrit Renker * Track the mean packet size `s' (cf. RFC 4342, 5.3 and RFC 3448, 4.1) 16778ad713dSGerrit Renker * @len: DCCP packet payload size in bytes 16878ad713dSGerrit Renker */ 16978ad713dSGerrit Renker static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hctx, int len) 17078ad713dSGerrit Renker { 171842d1ef1SGerrit Renker const u16 old_s = hctx->s; 1721266adeeSGerrit Renker 173842d1ef1SGerrit Renker hctx->s = tfrc_ewma(hctx->s, len, 9); 1741266adeeSGerrit Renker 175842d1ef1SGerrit Renker if (hctx->s != old_s) 1761266adeeSGerrit Renker ccid3_update_send_interval(hctx); 17778ad713dSGerrit Renker } 17878ad713dSGerrit Renker 1799f8681dbSGerrit Renker /* 1809f8681dbSGerrit Renker * Update Window Counter using the algorithm from [RFC 4342, 8.1]. 181825de27dSGerrit Renker * As elsewhere, RTT > 0 is assumed by using dccp_sample_rtt(). 1829f8681dbSGerrit Renker */ 1839f8681dbSGerrit Renker static inline void ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock *hctx, 1848132da4dSGerrit Renker ktime_t now) 1859f8681dbSGerrit Renker { 186842d1ef1SGerrit Renker u32 delta = ktime_us_delta(now, hctx->t_last_win_count), 187842d1ef1SGerrit Renker quarter_rtts = (4 * delta) / hctx->rtt; 1889f8681dbSGerrit Renker 1899f8681dbSGerrit Renker if (quarter_rtts > 0) { 190842d1ef1SGerrit Renker hctx->t_last_win_count = now; 191842d1ef1SGerrit Renker hctx->last_win_count += min(quarter_rtts, 5U); 192842d1ef1SGerrit Renker hctx->last_win_count &= 0xF; /* mod 16 */ 1939f8681dbSGerrit Renker } 1949f8681dbSGerrit Renker } 1959f8681dbSGerrit Renker 1967c657876SArnaldo Carvalho de Melo static void ccid3_hc_tx_no_feedback_timer(unsigned long data) 1977c657876SArnaldo Carvalho de Melo { 1987c657876SArnaldo Carvalho de Melo struct sock *sk = (struct sock *)data; 19959725dc2SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 2002a1fda6fSGerrit Renker unsigned long t_nfb = USEC_PER_SEC / 5; 2017c657876SArnaldo Carvalho de Melo 2027c657876SArnaldo Carvalho de Melo bh_lock_sock(sk); 2037c657876SArnaldo Carvalho de Melo if (sock_owned_by_user(sk)) { 2047c657876SArnaldo Carvalho de Melo /* Try again later. */ 2057c657876SArnaldo Carvalho de Melo /* XXX: set some sensible MIB */ 20648e03eeeSGerrit Renker goto restart_timer; 2077c657876SArnaldo Carvalho de Melo } 2087c657876SArnaldo Carvalho de Melo 209a9672411SGerrit Renker ccid3_pr_debug("%s(%p, state=%s) - entry \n", dccp_role(sk), sk, 210842d1ef1SGerrit Renker ccid3_tx_state_name(hctx->state)); 2117c657876SArnaldo Carvalho de Melo 212d0995e6aSGerrit Renker /* Ignore and do not restart after leaving the established state */ 213d0995e6aSGerrit Renker if ((1 << sk->sk_state) & ~(DCCPF_OPEN | DCCPF_PARTOPEN)) 214d0995e6aSGerrit Renker goto out; 215d0995e6aSGerrit Renker 216d0995e6aSGerrit Renker /* Reset feedback state to "no feedback received" */ 217842d1ef1SGerrit Renker if (hctx->state == TFRC_SSTATE_FBACK) 21852515e77SGerrit Renker ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK); 21952515e77SGerrit Renker 22052515e77SGerrit Renker /* 22152515e77SGerrit Renker * Determine new allowed sending rate X as per draft rfc3448bis-00, 4.4 222842d1ef1SGerrit Renker * RTO is 0 if and only if no feedback has been received yet. 22352515e77SGerrit Renker */ 224842d1ef1SGerrit Renker if (hctx->t_rto == 0 || hctx->p == 0) { 22552515e77SGerrit Renker 22652515e77SGerrit Renker /* halve send rate directly */ 227842d1ef1SGerrit Renker hctx->x = max(hctx->x / 2, (((u64)hctx->s) << 6) / TFRC_T_MBI); 2281266adeeSGerrit Renker ccid3_update_send_interval(hctx); 22952515e77SGerrit Renker } else { 2301f2333aeSArnaldo Carvalho de Melo /* 23152515e77SGerrit Renker * Modify the cached value of X_recv 232ff586298SGerrit Renker * 23352515e77SGerrit Renker * If (X_calc > 2 * X_recv) 2347c657876SArnaldo Carvalho de Melo * X_recv = max(X_recv / 2, s / (2 * t_mbi)); 2357c657876SArnaldo Carvalho de Melo * Else 2367c657876SArnaldo Carvalho de Melo * X_recv = X_calc / 4; 2371a21e49aSGerrit Renker * 2381a21e49aSGerrit Renker * Note that X_recv is scaled by 2^6 while X_calc is not 2397c657876SArnaldo Carvalho de Melo */ 240842d1ef1SGerrit Renker BUG_ON(hctx->p && !hctx->x_calc); 2417c657876SArnaldo Carvalho de Melo 242842d1ef1SGerrit Renker if (hctx->x_calc > (hctx->x_recv >> 5)) 243842d1ef1SGerrit Renker hctx->x_recv = 244842d1ef1SGerrit Renker max(hctx->x_recv / 2, 245842d1ef1SGerrit Renker (((__u64)hctx->s) << 6) / (2 * TFRC_T_MBI)); 24652515e77SGerrit Renker else { 247842d1ef1SGerrit Renker hctx->x_recv = hctx->x_calc; 248842d1ef1SGerrit Renker hctx->x_recv <<= 4; 2499e8efc82SGerrit Renker } 250aa97efd9SGerrit Renker ccid3_hc_tx_update_x(sk, NULL); 25152515e77SGerrit Renker } 25252515e77SGerrit Renker ccid3_pr_debug("Reduced X to %llu/64 bytes/sec\n", 253842d1ef1SGerrit Renker (unsigned long long)hctx->x); 25452515e77SGerrit Renker 2556b5e633aSArnaldo Carvalho de Melo /* 25652515e77SGerrit Renker * Set new timeout for the nofeedback timer. 2578a508ac2SGerrit Renker * See comments in packet_recv() regarding the value of t_RTO. 2586b5e633aSArnaldo Carvalho de Melo */ 259842d1ef1SGerrit Renker if (unlikely(hctx->t_rto == 0)) /* no feedback received yet */ 26052515e77SGerrit Renker t_nfb = TFRC_INITIAL_TIMEOUT; 26152515e77SGerrit Renker else 262842d1ef1SGerrit Renker t_nfb = max(hctx->t_rto, 2 * hctx->t_ipi); 2637c657876SArnaldo Carvalho de Melo 26448e03eeeSGerrit Renker restart_timer: 265842d1ef1SGerrit Renker sk_reset_timer(sk, &hctx->no_feedback_timer, 2662a1fda6fSGerrit Renker jiffies + usecs_to_jiffies(t_nfb)); 2677c657876SArnaldo Carvalho de Melo out: 2687c657876SArnaldo Carvalho de Melo bh_unlock_sock(sk); 2697c657876SArnaldo Carvalho de Melo sock_put(sk); 2707c657876SArnaldo Carvalho de Melo } 2717c657876SArnaldo Carvalho de Melo 272f4a66ca4SGerrit Renker /** 273f4a66ca4SGerrit Renker * ccid3_hc_tx_send_packet - Delay-based dequeueing of TX packets 274f4a66ca4SGerrit Renker * @skb: next packet candidate to send on @sk 275f4a66ca4SGerrit Renker * This function uses the convention of ccid_packet_dequeue_eval() and 276f4a66ca4SGerrit Renker * returns a millisecond-delay value between 0 and t_mbi = 64000 msec. 2777da7f456SGerrit Renker */ 2786b57c93dSGerrit Renker static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb) 2797c657876SArnaldo Carvalho de Melo { 2807c657876SArnaldo Carvalho de Melo struct dccp_sock *dp = dccp_sk(sk); 28159725dc2SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 2828132da4dSGerrit Renker ktime_t now = ktime_get_real(); 2838132da4dSGerrit Renker s64 delay; 2847c657876SArnaldo Carvalho de Melo 2857c657876SArnaldo Carvalho de Melo /* 286da335bafSGerrit Renker * This function is called only for Data and DataAck packets. Sending 287da335bafSGerrit Renker * zero-sized Data(Ack)s is theoretically possible, but for congestion 288da335bafSGerrit Renker * control this case is pathological - ignore it. 2897c657876SArnaldo Carvalho de Melo */ 2906b57c93dSGerrit Renker if (unlikely(skb->len == 0)) 291da335bafSGerrit Renker return -EBADMSG; 2927c657876SArnaldo Carvalho de Melo 293d0995e6aSGerrit Renker if (hctx->state == TFRC_SSTATE_NO_SENT) { 294842d1ef1SGerrit Renker sk_reset_timer(sk, &hctx->no_feedback_timer, (jiffies + 2958109b02bSArnaldo Carvalho de Melo usecs_to_jiffies(TFRC_INITIAL_TIMEOUT))); 296842d1ef1SGerrit Renker hctx->last_win_count = 0; 297842d1ef1SGerrit Renker hctx->t_last_win_count = now; 29890feeb95SGerrit Renker 29990feeb95SGerrit Renker /* Set t_0 for initial packet */ 300842d1ef1SGerrit Renker hctx->t_nom = now; 30130833ffeSGerrit Renker 302842d1ef1SGerrit Renker hctx->s = skb->len; 30330833ffeSGerrit Renker 30430833ffeSGerrit Renker /* 30530833ffeSGerrit Renker * Use initial RTT sample when available: recommended by erratum 30630833ffeSGerrit Renker * to RFC 4342. This implements the initialisation procedure of 30730833ffeSGerrit Renker * draft rfc3448bis, section 4.2. Remember, X is scaled by 2^6. 30830833ffeSGerrit Renker */ 30930833ffeSGerrit Renker if (dp->dccps_syn_rtt) { 31030833ffeSGerrit Renker ccid3_pr_debug("SYN RTT = %uus\n", dp->dccps_syn_rtt); 311842d1ef1SGerrit Renker hctx->rtt = dp->dccps_syn_rtt; 312842d1ef1SGerrit Renker hctx->x = rfc3390_initial_rate(sk); 313842d1ef1SGerrit Renker hctx->t_ld = now; 31430833ffeSGerrit Renker } else { 3153294f202SGerrit Renker /* 3163294f202SGerrit Renker * Sender does not have RTT sample: 3173294f202SGerrit Renker * - set fallback RTT (RFC 4340, 3.4) since a RTT value 3183294f202SGerrit Renker * is needed in several parts (e.g. window counter); 3193294f202SGerrit Renker * - set sending rate X_pps = 1pps as per RFC 3448, 4.2. 3203294f202SGerrit Renker */ 321842d1ef1SGerrit Renker hctx->rtt = DCCP_FALLBACK_RTT; 322842d1ef1SGerrit Renker hctx->x = hctx->s; 323842d1ef1SGerrit Renker hctx->x <<= 6; 32430833ffeSGerrit Renker } 32530833ffeSGerrit Renker ccid3_update_send_interval(hctx); 32630833ffeSGerrit Renker 32730833ffeSGerrit Renker ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK); 328d0995e6aSGerrit Renker 329d0995e6aSGerrit Renker } else { 330842d1ef1SGerrit Renker delay = ktime_us_delta(hctx->t_nom, now); 3318699be7dSIan McDonald ccid3_pr_debug("delay=%ld\n", (long)delay); 33291cf5a17SGerrit Renker /* 33391cf5a17SGerrit Renker * Scheduling of packet transmissions [RFC 3448, 4.6] 33491cf5a17SGerrit Renker * 33591cf5a17SGerrit Renker * if (t_now > t_nom - delta) 33691cf5a17SGerrit Renker * // send the packet now 33791cf5a17SGerrit Renker * else 33891cf5a17SGerrit Renker * // send the packet in (t_nom - t_now) milliseconds. 33991cf5a17SGerrit Renker */ 340de6f2b59SGerrit Renker if (delay >= TFRC_T_DELTA) 341de6f2b59SGerrit Renker return (u32)delay / USEC_PER_MSEC; 3429f8681dbSGerrit Renker 3438132da4dSGerrit Renker ccid3_hc_tx_update_win_count(hctx, now); 3447c657876SArnaldo Carvalho de Melo } 3457c657876SArnaldo Carvalho de Melo 3467da7f456SGerrit Renker /* prepare to send now (add options etc.) */ 347507d37cfSArnaldo Carvalho de Melo dp->dccps_hc_tx_insert_options = 1; 348842d1ef1SGerrit Renker DCCP_SKB_CB(skb)->dccpd_ccval = hctx->last_win_count; 349e312d100SGerrit Renker 350e312d100SGerrit Renker /* set the nominal send time for the next following packet */ 351842d1ef1SGerrit Renker hctx->t_nom = ktime_add_us(hctx->t_nom, hctx->t_ipi); 352f4a66ca4SGerrit Renker return CCID_PACKET_SEND_AT_ONCE; 3537c657876SArnaldo Carvalho de Melo } 3547c657876SArnaldo Carvalho de Melo 355c506d91dSGerrit Renker static void ccid3_hc_tx_packet_sent(struct sock *sk, unsigned int len) 3567c657876SArnaldo Carvalho de Melo { 35759725dc2SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 3587c657876SArnaldo Carvalho de Melo 35978ad713dSGerrit Renker ccid3_hc_tx_update_s(hctx, len); 36078ad713dSGerrit Renker 361842d1ef1SGerrit Renker if (tfrc_tx_hist_add(&hctx->hist, dccp_sk(sk)->dccps_gss)) 362c5a1ae9aSGerrit Renker DCCP_CRIT("packet history - out of memory!"); 3637c657876SArnaldo Carvalho de Melo } 3647c657876SArnaldo Carvalho de Melo 3657c657876SArnaldo Carvalho de Melo static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) 3667c657876SArnaldo Carvalho de Melo { 36759725dc2SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 36863b3a73bSGerrit Renker struct tfrc_tx_hist_entry *acked; 3690740d49cSArnaldo Carvalho de Melo ktime_t now; 3702a1fda6fSGerrit Renker unsigned long t_nfb; 371ce177ae2SGerrit Renker u32 r_sample; 3721f2333aeSArnaldo Carvalho de Melo 3737c657876SArnaldo Carvalho de Melo /* we are only interested in ACKs */ 3747c657876SArnaldo Carvalho de Melo if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK || 3757c657876SArnaldo Carvalho de Melo DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK)) 3767c657876SArnaldo Carvalho de Melo return; 37763b3a73bSGerrit Renker /* 37863b3a73bSGerrit Renker * Locate the acknowledged packet in the TX history. 37963b3a73bSGerrit Renker * 38063b3a73bSGerrit Renker * Returning "entry not found" here can for instance happen when 38163b3a73bSGerrit Renker * - the host has not sent out anything (e.g. a passive server), 38263b3a73bSGerrit Renker * - the Ack is outdated (packet with higher Ack number was received), 38363b3a73bSGerrit Renker * - it is a bogus Ack (for a packet not sent on this connection). 38463b3a73bSGerrit Renker */ 38563b3a73bSGerrit Renker acked = tfrc_tx_hist_find_entry(hctx->hist, dccp_hdr_ack_seq(skb)); 38663b3a73bSGerrit Renker if (acked == NULL) 3877c657876SArnaldo Carvalho de Melo return; 38863b3a73bSGerrit Renker /* For the sake of RTT sampling, ignore/remove all older entries */ 38963b3a73bSGerrit Renker tfrc_tx_hist_purge(&acked->next); 39063b3a73bSGerrit Renker 39163b3a73bSGerrit Renker /* Update the moving average for the RTT estimate (RFC 3448, 4.3) */ 39263b3a73bSGerrit Renker now = ktime_get_real(); 39363b3a73bSGerrit Renker r_sample = dccp_sample_rtt(sk, ktime_us_delta(now, acked->stamp)); 39463b3a73bSGerrit Renker hctx->rtt = tfrc_ewma(hctx->rtt, r_sample, 9); 3957c657876SArnaldo Carvalho de Melo 3961a21e49aSGerrit Renker /* 397d8d1252fSGerrit Renker * Update allowed sending rate X as per draft rfc3448bis-00, 4.2/3 398d8d1252fSGerrit Renker */ 399842d1ef1SGerrit Renker if (hctx->state == TFRC_SSTATE_NO_FBACK) { 400d8d1252fSGerrit Renker ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK); 401d8d1252fSGerrit Renker 402842d1ef1SGerrit Renker if (hctx->t_rto == 0) { 403d8d1252fSGerrit Renker /* 404d8d1252fSGerrit Renker * Initial feedback packet: Larger Initial Windows (4.2) 4051a21e49aSGerrit Renker */ 406842d1ef1SGerrit Renker hctx->x = rfc3390_initial_rate(sk); 407842d1ef1SGerrit Renker hctx->t_ld = now; 408a79ef76fSGerrit Renker 4091266adeeSGerrit Renker ccid3_update_send_interval(hctx); 4105c3fbb6aSGerrit Renker 411d8d1252fSGerrit Renker goto done_computing_x; 412842d1ef1SGerrit Renker } else if (hctx->p == 0) { 413d8d1252fSGerrit Renker /* 414d8d1252fSGerrit Renker * First feedback after nofeedback timer expiry (4.3) 415d8d1252fSGerrit Renker */ 416d8d1252fSGerrit Renker goto done_computing_x; 417d8d1252fSGerrit Renker } 418d8d1252fSGerrit Renker } 4195c3fbb6aSGerrit Renker 420ff586298SGerrit Renker /* Update sending rate (step 4 of [RFC 3448, 4.3]) */ 421842d1ef1SGerrit Renker if (hctx->p > 0) 422842d1ef1SGerrit Renker hctx->x_calc = tfrc_calc_x(hctx->s, hctx->rtt, hctx->p); 423aa97efd9SGerrit Renker ccid3_hc_tx_update_x(sk, &now); 4247c657876SArnaldo Carvalho de Melo 425d8d1252fSGerrit Renker done_computing_x: 4267dfee1a9SGerrit Renker ccid3_pr_debug("%s(%p), RTT=%uus (sample=%uus), s=%u, " 4278109b02bSArnaldo Carvalho de Melo "p=%u, X_calc=%u, X_recv=%u, X=%u\n", 428842d1ef1SGerrit Renker dccp_role(sk), sk, hctx->rtt, r_sample, 429842d1ef1SGerrit Renker hctx->s, hctx->p, hctx->x_calc, 430842d1ef1SGerrit Renker (unsigned)(hctx->x_recv >> 6), 431842d1ef1SGerrit Renker (unsigned)(hctx->x >> 6)); 4327c657876SArnaldo Carvalho de Melo 4337c657876SArnaldo Carvalho de Melo /* unschedule no feedback timer */ 434842d1ef1SGerrit Renker sk_stop_timer(sk, &hctx->no_feedback_timer); 4357c657876SArnaldo Carvalho de Melo 436c530cfb1SArnaldo Carvalho de Melo /* 4378109b02bSArnaldo Carvalho de Melo * As we have calculated new ipi, delta, t_nom it is possible 4388109b02bSArnaldo Carvalho de Melo * that we now can send a packet, so wake up dccp_wait_for_ccid 439c530cfb1SArnaldo Carvalho de Melo */ 440c530cfb1SArnaldo Carvalho de Melo sk->sk_write_space(sk); 4418c60f3faSArnaldo Carvalho de Melo 4428a508ac2SGerrit Renker /* 4438a508ac2SGerrit Renker * Update timeout interval for the nofeedback timer. 4448a508ac2SGerrit Renker * We use a configuration option to increase the lower bound. 4458109b02bSArnaldo Carvalho de Melo * This can help avoid triggering the nofeedback timer too 4468109b02bSArnaldo Carvalho de Melo * often ('spinning') on LANs with small RTTs. 4478a508ac2SGerrit Renker */ 448842d1ef1SGerrit Renker hctx->t_rto = max_t(u32, 4 * hctx->rtt, (CONFIG_IP_DCCP_CCID3_RTO * 4495bd370a6SGerrit Renker (USEC_PER_SEC / 1000))); 4501f2333aeSArnaldo Carvalho de Melo /* 4511f2333aeSArnaldo Carvalho de Melo * Schedule no feedback timer to expire in 4528a508ac2SGerrit Renker * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi) 4531f2333aeSArnaldo Carvalho de Melo */ 454842d1ef1SGerrit Renker t_nfb = max(hctx->t_rto, 2 * hctx->t_ipi); 4557c657876SArnaldo Carvalho de Melo 456a9672411SGerrit Renker ccid3_pr_debug("%s(%p), Scheduled no feedback timer to " 4578109b02bSArnaldo Carvalho de Melo "expire in %lu jiffies (%luus)\n", 458842d1ef1SGerrit Renker dccp_role(sk), sk, usecs_to_jiffies(t_nfb), t_nfb); 4597c657876SArnaldo Carvalho de Melo 460842d1ef1SGerrit Renker sk_reset_timer(sk, &hctx->no_feedback_timer, 4612a1fda6fSGerrit Renker jiffies + usecs_to_jiffies(t_nfb)); 4627c657876SArnaldo Carvalho de Melo } 4637c657876SArnaldo Carvalho de Melo 4643306c781SGerrit Renker static int ccid3_hc_tx_parse_options(struct sock *sk, u8 packet_type, 4653306c781SGerrit Renker u8 option, u8 *optval, u8 optlen) 4667c657876SArnaldo Carvalho de Melo { 46759725dc2SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 46876fd1e87SGerrit Renker __be32 opt_val; 4697c657876SArnaldo Carvalho de Melo 4707c657876SArnaldo Carvalho de Melo switch (option) { 47147a61e7bSGerrit Renker case TFRC_OPT_RECEIVE_RATE: 4727c657876SArnaldo Carvalho de Melo case TFRC_OPT_LOSS_EVENT_RATE: 4733306c781SGerrit Renker /* Must be ignored on Data packets, cf. RFC 4342 8.3 and 8.5 */ 4743306c781SGerrit Renker if (packet_type == DCCP_PKT_DATA) 4753306c781SGerrit Renker break; 4763306c781SGerrit Renker if (unlikely(optlen != 4)) { 47747a61e7bSGerrit Renker DCCP_WARN("%s(%p), invalid len %d for %u\n", 4783306c781SGerrit Renker dccp_role(sk), sk, optlen, option); 47947a61e7bSGerrit Renker return -EINVAL; 4807c657876SArnaldo Carvalho de Melo } 4813306c781SGerrit Renker opt_val = ntohl(get_unaligned((__be32 *)optval)); 4827c657876SArnaldo Carvalho de Melo 48347a61e7bSGerrit Renker if (option == TFRC_OPT_RECEIVE_RATE) { 484ce177ae2SGerrit Renker /* Receive Rate is kept in units of 64 bytes/second */ 485ce177ae2SGerrit Renker hctx->x_recv = opt_val; 486ce177ae2SGerrit Renker hctx->x_recv <<= 6; 487ce177ae2SGerrit Renker 48847a61e7bSGerrit Renker ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n", 48947a61e7bSGerrit Renker dccp_role(sk), sk, opt_val); 49047a61e7bSGerrit Renker } else { 491ce177ae2SGerrit Renker /* Update the fixpoint Loss Event Rate fraction */ 492ce177ae2SGerrit Renker hctx->p = tfrc_invert_loss_event_rate(opt_val); 493ce177ae2SGerrit Renker 49447a61e7bSGerrit Renker ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n", 49547a61e7bSGerrit Renker dccp_role(sk), sk, opt_val); 49647a61e7bSGerrit Renker } 49747a61e7bSGerrit Renker } 49847a61e7bSGerrit Renker return 0; 4997c657876SArnaldo Carvalho de Melo } 5007c657876SArnaldo Carvalho de Melo 50191f0ebf7SArnaldo Carvalho de Melo static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk) 5027c657876SArnaldo Carvalho de Melo { 50391f0ebf7SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid_priv(ccid); 5047c657876SArnaldo Carvalho de Melo 505842d1ef1SGerrit Renker hctx->state = TFRC_SSTATE_NO_SENT; 506842d1ef1SGerrit Renker hctx->hist = NULL; 507842d1ef1SGerrit Renker setup_timer(&hctx->no_feedback_timer, 508b24b8a24SPavel Emelyanov ccid3_hc_tx_no_feedback_timer, (unsigned long)sk); 5097c657876SArnaldo Carvalho de Melo return 0; 5107c657876SArnaldo Carvalho de Melo } 5117c657876SArnaldo Carvalho de Melo 5127c657876SArnaldo Carvalho de Melo static void ccid3_hc_tx_exit(struct sock *sk) 5137c657876SArnaldo Carvalho de Melo { 51459725dc2SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 5157c657876SArnaldo Carvalho de Melo 516842d1ef1SGerrit Renker sk_stop_timer(sk, &hctx->no_feedback_timer); 517842d1ef1SGerrit Renker tfrc_tx_hist_purge(&hctx->hist); 5187c657876SArnaldo Carvalho de Melo } 5197c657876SArnaldo Carvalho de Melo 5209bf17475SGerrit Renker static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info) 5219bf17475SGerrit Renker { 522b2e317f4SGerrit Renker info->tcpi_rto = ccid3_hc_tx_sk(sk)->t_rto; 523b2e317f4SGerrit Renker info->tcpi_rtt = ccid3_hc_tx_sk(sk)->rtt; 5249bf17475SGerrit Renker } 5259bf17475SGerrit Renker 5269bf17475SGerrit Renker static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len, 5279bf17475SGerrit Renker u32 __user *optval, int __user *optlen) 5289bf17475SGerrit Renker { 529b2e317f4SGerrit Renker const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 530842d1ef1SGerrit Renker struct tfrc_tx_info tfrc; 5319bf17475SGerrit Renker const void *val; 5329bf17475SGerrit Renker 5339bf17475SGerrit Renker switch (optname) { 5349bf17475SGerrit Renker case DCCP_SOCKOPT_CCID_TX_INFO: 535842d1ef1SGerrit Renker if (len < sizeof(tfrc)) 5369bf17475SGerrit Renker return -EINVAL; 537842d1ef1SGerrit Renker tfrc.tfrctx_x = hctx->x; 538842d1ef1SGerrit Renker tfrc.tfrctx_x_recv = hctx->x_recv; 539842d1ef1SGerrit Renker tfrc.tfrctx_x_calc = hctx->x_calc; 540842d1ef1SGerrit Renker tfrc.tfrctx_rtt = hctx->rtt; 541842d1ef1SGerrit Renker tfrc.tfrctx_p = hctx->p; 542842d1ef1SGerrit Renker tfrc.tfrctx_rto = hctx->t_rto; 543842d1ef1SGerrit Renker tfrc.tfrctx_ipi = hctx->t_ipi; 544842d1ef1SGerrit Renker len = sizeof(tfrc); 545842d1ef1SGerrit Renker val = &tfrc; 5469bf17475SGerrit Renker break; 5479bf17475SGerrit Renker default: 5489bf17475SGerrit Renker return -ENOPROTOOPT; 5499bf17475SGerrit Renker } 5509bf17475SGerrit Renker 5519bf17475SGerrit Renker if (put_user(len, optlen) || copy_to_user(optval, val, len)) 5529bf17475SGerrit Renker return -EFAULT; 5539bf17475SGerrit Renker 5549bf17475SGerrit Renker return 0; 5559bf17475SGerrit Renker } 5569bf17475SGerrit Renker 5579bf17475SGerrit Renker /* 5589bf17475SGerrit Renker * Receiver Half-Connection Routines 5599bf17475SGerrit Renker */ 560b84a2189SArnaldo Carvalho de Melo 561b84a2189SArnaldo Carvalho de Melo /* CCID3 feedback types */ 562b84a2189SArnaldo Carvalho de Melo enum ccid3_fback_type { 563b84a2189SArnaldo Carvalho de Melo CCID3_FBACK_NONE = 0, 564b84a2189SArnaldo Carvalho de Melo CCID3_FBACK_INITIAL, 565b84a2189SArnaldo Carvalho de Melo CCID3_FBACK_PERIODIC, 566b84a2189SArnaldo Carvalho de Melo CCID3_FBACK_PARAM_CHANGE 567b84a2189SArnaldo Carvalho de Melo }; 568b84a2189SArnaldo Carvalho de Melo 56956724aa4SGerrit Renker #ifdef CONFIG_IP_DCCP_CCID3_DEBUG 5707c657876SArnaldo Carvalho de Melo static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state) 5717c657876SArnaldo Carvalho de Melo { 5727c657876SArnaldo Carvalho de Melo static char *ccid3_rx_state_names[] = { 5737c657876SArnaldo Carvalho de Melo [TFRC_RSTATE_NO_DATA] = "NO_DATA", 5747c657876SArnaldo Carvalho de Melo [TFRC_RSTATE_DATA] = "DATA", 5757c657876SArnaldo Carvalho de Melo }; 5767c657876SArnaldo Carvalho de Melo 5777c657876SArnaldo Carvalho de Melo return ccid3_rx_state_names[state]; 5787c657876SArnaldo Carvalho de Melo } 5797c657876SArnaldo Carvalho de Melo #endif 5807c657876SArnaldo Carvalho de Melo 581c25a18baSArnaldo Carvalho de Melo static void ccid3_hc_rx_set_state(struct sock *sk, 5821f2333aeSArnaldo Carvalho de Melo enum ccid3_hc_rx_states state) 5837c657876SArnaldo Carvalho de Melo { 58459725dc2SArnaldo Carvalho de Melo struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 585842d1ef1SGerrit Renker enum ccid3_hc_rx_states oldstate = hcrx->state; 5867c657876SArnaldo Carvalho de Melo 5877c657876SArnaldo Carvalho de Melo ccid3_pr_debug("%s(%p) %-8.8s -> %s\n", 5881f2333aeSArnaldo Carvalho de Melo dccp_role(sk), sk, ccid3_rx_state_name(oldstate), 5891f2333aeSArnaldo Carvalho de Melo ccid3_rx_state_name(state)); 5907c657876SArnaldo Carvalho de Melo WARN_ON(state == oldstate); 591842d1ef1SGerrit Renker hcrx->state = state; 5927c657876SArnaldo Carvalho de Melo } 5937c657876SArnaldo Carvalho de Melo 594b84a2189SArnaldo Carvalho de Melo static void ccid3_hc_rx_send_feedback(struct sock *sk, 595b84a2189SArnaldo Carvalho de Melo const struct sk_buff *skb, 596b84a2189SArnaldo Carvalho de Melo enum ccid3_fback_type fbtype) 5977c657876SArnaldo Carvalho de Melo { 59859725dc2SArnaldo Carvalho de Melo struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 5997c657876SArnaldo Carvalho de Melo struct dccp_sock *dp = dccp_sk(sk); 600d0995e6aSGerrit Renker ktime_t now = ktime_get_real(); 601b84a2189SArnaldo Carvalho de Melo s64 delta = 0; 6027c657876SArnaldo Carvalho de Melo 603b84a2189SArnaldo Carvalho de Melo switch (fbtype) { 604b84a2189SArnaldo Carvalho de Melo case CCID3_FBACK_INITIAL: 605842d1ef1SGerrit Renker hcrx->x_recv = 0; 606842d1ef1SGerrit Renker hcrx->p_inverse = ~0U; /* see RFC 4342, 8.5 */ 6077c657876SArnaldo Carvalho de Melo break; 608b84a2189SArnaldo Carvalho de Melo case CCID3_FBACK_PARAM_CHANGE: 609b84a2189SArnaldo Carvalho de Melo /* 610b84a2189SArnaldo Carvalho de Melo * When parameters change (new loss or p > p_prev), we do not 611b84a2189SArnaldo Carvalho de Melo * have a reliable estimate for R_m of [RFC 3448, 6.2] and so 612b84a2189SArnaldo Carvalho de Melo * need to reuse the previous value of X_recv. However, when 613b84a2189SArnaldo Carvalho de Melo * X_recv was 0 (due to early loss), this would kill X down to 614b84a2189SArnaldo Carvalho de Melo * s/t_mbi (i.e. one packet in 64 seconds). 615b84a2189SArnaldo Carvalho de Melo * To avoid such drastic reduction, we approximate X_recv as 616b84a2189SArnaldo Carvalho de Melo * the number of bytes since last feedback. 617b84a2189SArnaldo Carvalho de Melo * This is a safe fallback, since X is bounded above by X_calc. 618b84a2189SArnaldo Carvalho de Melo */ 619842d1ef1SGerrit Renker if (hcrx->x_recv > 0) 620b84a2189SArnaldo Carvalho de Melo break; 621b84a2189SArnaldo Carvalho de Melo /* fall through */ 622b84a2189SArnaldo Carvalho de Melo case CCID3_FBACK_PERIODIC: 623842d1ef1SGerrit Renker delta = ktime_us_delta(now, hcrx->tstamp_last_feedback); 624b84a2189SArnaldo Carvalho de Melo if (delta <= 0) 625b84a2189SArnaldo Carvalho de Melo DCCP_BUG("delta (%ld) <= 0", (long)delta); 626b84a2189SArnaldo Carvalho de Melo else 627842d1ef1SGerrit Renker hcrx->x_recv = scaled_div32(hcrx->bytes_recv, delta); 6287c657876SArnaldo Carvalho de Melo break; 629b84a2189SArnaldo Carvalho de Melo default: 6307c657876SArnaldo Carvalho de Melo return; 6317c657876SArnaldo Carvalho de Melo } 6327c657876SArnaldo Carvalho de Melo 633842d1ef1SGerrit Renker ccid3_pr_debug("Interval %ldusec, X_recv=%u, 1/p=%u\n", 634842d1ef1SGerrit Renker (long)delta, hcrx->x_recv, hcrx->p_inverse); 6357c657876SArnaldo Carvalho de Melo 636842d1ef1SGerrit Renker hcrx->tstamp_last_feedback = now; 637842d1ef1SGerrit Renker hcrx->last_counter = dccp_hdr(skb)->dccph_ccval; 638842d1ef1SGerrit Renker hcrx->bytes_recv = 0; 6397c657876SArnaldo Carvalho de Melo 640507d37cfSArnaldo Carvalho de Melo dp->dccps_hc_rx_insert_options = 1; 6417c657876SArnaldo Carvalho de Melo dccp_send_ack(sk); 6427c657876SArnaldo Carvalho de Melo } 6437c657876SArnaldo Carvalho de Melo 6442d0817d1SArnaldo Carvalho de Melo static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb) 6457c657876SArnaldo Carvalho de Melo { 646b2e317f4SGerrit Renker const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 64760fe62e7SAndrea Bittau __be32 x_recv, pinv; 6487c657876SArnaldo Carvalho de Melo 64959d203f9SArnaldo Carvalho de Melo if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN)) 6502d0817d1SArnaldo Carvalho de Melo return 0; 6517c657876SArnaldo Carvalho de Melo 6524fded33bSArnaldo Carvalho de Melo if (dccp_packet_without_ack(skb)) 6532d0817d1SArnaldo Carvalho de Melo return 0; 6544fded33bSArnaldo Carvalho de Melo 655842d1ef1SGerrit Renker x_recv = htonl(hcrx->x_recv); 656842d1ef1SGerrit Renker pinv = htonl(hcrx->p_inverse); 6572d0817d1SArnaldo Carvalho de Melo 658385ac2e3SGerrit Renker if (dccp_insert_option(sk, skb, TFRC_OPT_LOSS_EVENT_RATE, 6592d0817d1SArnaldo Carvalho de Melo &pinv, sizeof(pinv)) || 6604fded33bSArnaldo Carvalho de Melo dccp_insert_option(sk, skb, TFRC_OPT_RECEIVE_RATE, 6612d0817d1SArnaldo Carvalho de Melo &x_recv, sizeof(x_recv))) 6622d0817d1SArnaldo Carvalho de Melo return -1; 6632d0817d1SArnaldo Carvalho de Melo 6642d0817d1SArnaldo Carvalho de Melo return 0; 6657c657876SArnaldo Carvalho de Melo } 6667c657876SArnaldo Carvalho de Melo 667954c2db8SGerrit Renker /** ccid3_first_li - Implements [RFC 3448, 6.3.1] 668954c2db8SGerrit Renker * 669954c2db8SGerrit Renker * Determine the length of the first loss interval via inverse lookup. 670954c2db8SGerrit Renker * Assume that X_recv can be computed by the throughput equation 671954c2db8SGerrit Renker * s 672954c2db8SGerrit Renker * X_recv = -------- 673954c2db8SGerrit Renker * R * fval 674954c2db8SGerrit Renker * Find some p such that f(p) = fval; return 1/p (scaled). 675954c2db8SGerrit Renker */ 676954c2db8SGerrit Renker static u32 ccid3_first_li(struct sock *sk) 677954c2db8SGerrit Renker { 678954c2db8SGerrit Renker struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 679954c2db8SGerrit Renker u32 x_recv, p, delta; 680954c2db8SGerrit Renker u64 fval; 681954c2db8SGerrit Renker 682842d1ef1SGerrit Renker if (hcrx->rtt == 0) { 683954c2db8SGerrit Renker DCCP_WARN("No RTT estimate available, using fallback RTT\n"); 684842d1ef1SGerrit Renker hcrx->rtt = DCCP_FALLBACK_RTT; 685954c2db8SGerrit Renker } 686954c2db8SGerrit Renker 687842d1ef1SGerrit Renker delta = ktime_to_us(net_timedelta(hcrx->tstamp_last_feedback)); 688842d1ef1SGerrit Renker x_recv = scaled_div32(hcrx->bytes_recv, delta); 689954c2db8SGerrit Renker if (x_recv == 0) { /* would also trigger divide-by-zero */ 690954c2db8SGerrit Renker DCCP_WARN("X_recv==0\n"); 691842d1ef1SGerrit Renker if (hcrx->x_recv == 0) { 692954c2db8SGerrit Renker DCCP_BUG("stored value of X_recv is zero"); 693954c2db8SGerrit Renker return ~0U; 694954c2db8SGerrit Renker } 695842d1ef1SGerrit Renker x_recv = hcrx->x_recv; 696954c2db8SGerrit Renker } 697954c2db8SGerrit Renker 698842d1ef1SGerrit Renker fval = scaled_div(hcrx->s, hcrx->rtt); 699954c2db8SGerrit Renker fval = scaled_div32(fval, x_recv); 700954c2db8SGerrit Renker p = tfrc_calc_x_reverse_lookup(fval); 701954c2db8SGerrit Renker 702954c2db8SGerrit Renker ccid3_pr_debug("%s(%p), receive rate=%u bytes/s, implied " 703954c2db8SGerrit Renker "loss rate=%u\n", dccp_role(sk), sk, x_recv, p); 704954c2db8SGerrit Renker 705954c2db8SGerrit Renker return p == 0 ? ~0U : scaled_div(1, p); 706954c2db8SGerrit Renker } 707954c2db8SGerrit Renker 7087c657876SArnaldo Carvalho de Melo static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) 7097c657876SArnaldo Carvalho de Melo { 71059725dc2SArnaldo Carvalho de Melo struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 711b84a2189SArnaldo Carvalho de Melo enum ccid3_fback_type do_feedback = CCID3_FBACK_NONE; 7125b5d0e70SGerrit Renker const u64 ndp = dccp_sk(sk)->dccps_options_received.dccpor_ndp; 713b84a2189SArnaldo Carvalho de Melo const bool is_data_packet = dccp_data_packet(skb); 7141f2333aeSArnaldo Carvalho de Melo 715842d1ef1SGerrit Renker if (unlikely(hcrx->state == TFRC_RSTATE_NO_DATA)) { 716b84a2189SArnaldo Carvalho de Melo if (is_data_packet) { 717b84a2189SArnaldo Carvalho de Melo const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4; 718b84a2189SArnaldo Carvalho de Melo do_feedback = CCID3_FBACK_INITIAL; 7197c657876SArnaldo Carvalho de Melo ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA); 720842d1ef1SGerrit Renker hcrx->s = payload; 721b84a2189SArnaldo Carvalho de Melo /* 722842d1ef1SGerrit Renker * Not necessary to update bytes_recv here, 723b84a2189SArnaldo Carvalho de Melo * since X_recv = 0 for the first feedback packet (cf. 724b84a2189SArnaldo Carvalho de Melo * RFC 3448, 6.3) -- gerrit 725b84a2189SArnaldo Carvalho de Melo */ 7267c657876SArnaldo Carvalho de Melo } 727b84a2189SArnaldo Carvalho de Melo goto update_records; 7287c657876SArnaldo Carvalho de Melo } 7297c657876SArnaldo Carvalho de Melo 730842d1ef1SGerrit Renker if (tfrc_rx_hist_duplicate(&hcrx->hist, skb)) 731b84a2189SArnaldo Carvalho de Melo return; /* done receiving */ 7327c657876SArnaldo Carvalho de Melo 733b84a2189SArnaldo Carvalho de Melo if (is_data_packet) { 734b84a2189SArnaldo Carvalho de Melo const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4; 735b84a2189SArnaldo Carvalho de Melo /* 736b84a2189SArnaldo Carvalho de Melo * Update moving-average of s and the sum of received payload bytes 737b84a2189SArnaldo Carvalho de Melo */ 738842d1ef1SGerrit Renker hcrx->s = tfrc_ewma(hcrx->s, payload, 9); 739842d1ef1SGerrit Renker hcrx->bytes_recv += payload; 7407c657876SArnaldo Carvalho de Melo } 741b84a2189SArnaldo Carvalho de Melo 742b84a2189SArnaldo Carvalho de Melo /* 743b552c623SGerrit Renker * Perform loss detection and handle pending losses 744b84a2189SArnaldo Carvalho de Melo */ 745842d1ef1SGerrit Renker if (tfrc_rx_handle_loss(&hcrx->hist, &hcrx->li_hist, 746954c2db8SGerrit Renker skb, ndp, ccid3_first_li, sk)) { 747954c2db8SGerrit Renker do_feedback = CCID3_FBACK_PARAM_CHANGE; 748954c2db8SGerrit Renker goto done_receiving; 749954c2db8SGerrit Renker } 750954c2db8SGerrit Renker 751842d1ef1SGerrit Renker if (tfrc_rx_hist_loss_pending(&hcrx->hist)) 752b552c623SGerrit Renker return; /* done receiving */ 753b84a2189SArnaldo Carvalho de Melo 754b84a2189SArnaldo Carvalho de Melo /* 755b84a2189SArnaldo Carvalho de Melo * Handle data packets: RTT sampling and monitoring p 756b84a2189SArnaldo Carvalho de Melo */ 757b84a2189SArnaldo Carvalho de Melo if (unlikely(!is_data_packet)) 758b84a2189SArnaldo Carvalho de Melo goto update_records; 759b84a2189SArnaldo Carvalho de Melo 760842d1ef1SGerrit Renker if (!tfrc_lh_is_initialised(&hcrx->li_hist)) { 761842d1ef1SGerrit Renker const u32 sample = tfrc_rx_hist_sample_rtt(&hcrx->hist, skb); 762b84a2189SArnaldo Carvalho de Melo /* 763b84a2189SArnaldo Carvalho de Melo * Empty loss history: no loss so far, hence p stays 0. 764b84a2189SArnaldo Carvalho de Melo * Sample RTT values, since an RTT estimate is required for the 765b84a2189SArnaldo Carvalho de Melo * computation of p when the first loss occurs; RFC 3448, 6.3.1. 766b84a2189SArnaldo Carvalho de Melo */ 767b84a2189SArnaldo Carvalho de Melo if (sample != 0) 768842d1ef1SGerrit Renker hcrx->rtt = tfrc_ewma(hcrx->rtt, sample, 9); 769954c2db8SGerrit Renker 770842d1ef1SGerrit Renker } else if (tfrc_lh_update_i_mean(&hcrx->li_hist, skb)) { 771954c2db8SGerrit Renker /* 772954c2db8SGerrit Renker * Step (3) of [RFC 3448, 6.1]: Recompute I_mean and, if I_mean 773954c2db8SGerrit Renker * has decreased (resp. p has increased), send feedback now. 774954c2db8SGerrit Renker */ 775954c2db8SGerrit Renker do_feedback = CCID3_FBACK_PARAM_CHANGE; 776b84a2189SArnaldo Carvalho de Melo } 777b84a2189SArnaldo Carvalho de Melo 778b84a2189SArnaldo Carvalho de Melo /* 779b84a2189SArnaldo Carvalho de Melo * Check if the periodic once-per-RTT feedback is due; RFC 4342, 10.3 780b84a2189SArnaldo Carvalho de Melo */ 781842d1ef1SGerrit Renker if (SUB16(dccp_hdr(skb)->dccph_ccval, hcrx->last_counter) > 3) 782b84a2189SArnaldo Carvalho de Melo do_feedback = CCID3_FBACK_PERIODIC; 783b84a2189SArnaldo Carvalho de Melo 784b84a2189SArnaldo Carvalho de Melo update_records: 785842d1ef1SGerrit Renker tfrc_rx_hist_add_packet(&hcrx->hist, skb, ndp); 786b84a2189SArnaldo Carvalho de Melo 787954c2db8SGerrit Renker done_receiving: 788b84a2189SArnaldo Carvalho de Melo if (do_feedback) 789b84a2189SArnaldo Carvalho de Melo ccid3_hc_rx_send_feedback(sk, skb, do_feedback); 7907c657876SArnaldo Carvalho de Melo } 7917c657876SArnaldo Carvalho de Melo 79291f0ebf7SArnaldo Carvalho de Melo static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk) 7937c657876SArnaldo Carvalho de Melo { 79491f0ebf7SArnaldo Carvalho de Melo struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid); 7957c657876SArnaldo Carvalho de Melo 796842d1ef1SGerrit Renker hcrx->state = TFRC_RSTATE_NO_DATA; 797842d1ef1SGerrit Renker tfrc_lh_init(&hcrx->li_hist); 798842d1ef1SGerrit Renker return tfrc_rx_hist_alloc(&hcrx->hist); 7997c657876SArnaldo Carvalho de Melo } 8007c657876SArnaldo Carvalho de Melo 8017c657876SArnaldo Carvalho de Melo static void ccid3_hc_rx_exit(struct sock *sk) 8027c657876SArnaldo Carvalho de Melo { 80359725dc2SArnaldo Carvalho de Melo struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 8047c657876SArnaldo Carvalho de Melo 805842d1ef1SGerrit Renker tfrc_rx_hist_purge(&hcrx->hist); 806842d1ef1SGerrit Renker tfrc_lh_cleanup(&hcrx->li_hist); 8077c657876SArnaldo Carvalho de Melo } 8087c657876SArnaldo Carvalho de Melo 8092babe1f6SArnaldo Carvalho de Melo static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info) 8102babe1f6SArnaldo Carvalho de Melo { 811b2e317f4SGerrit Renker info->tcpi_ca_state = ccid3_hc_rx_sk(sk)->state; 8122babe1f6SArnaldo Carvalho de Melo info->tcpi_options |= TCPI_OPT_TIMESTAMPS; 813b2e317f4SGerrit Renker info->tcpi_rcv_rtt = ccid3_hc_rx_sk(sk)->rtt; 8142babe1f6SArnaldo Carvalho de Melo } 8152babe1f6SArnaldo Carvalho de Melo 81688f964dbSArnaldo Carvalho de Melo static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len, 81788f964dbSArnaldo Carvalho de Melo u32 __user *optval, int __user *optlen) 81888f964dbSArnaldo Carvalho de Melo { 819b2e317f4SGerrit Renker const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 8208e138e79SGerrit Renker struct tfrc_rx_info rx_info; 82188f964dbSArnaldo Carvalho de Melo const void *val; 82288f964dbSArnaldo Carvalho de Melo 82388f964dbSArnaldo Carvalho de Melo switch (optname) { 82488f964dbSArnaldo Carvalho de Melo case DCCP_SOCKOPT_CCID_RX_INFO: 8258e138e79SGerrit Renker if (len < sizeof(rx_info)) 82688f964dbSArnaldo Carvalho de Melo return -EINVAL; 827842d1ef1SGerrit Renker rx_info.tfrcrx_x_recv = hcrx->x_recv; 828842d1ef1SGerrit Renker rx_info.tfrcrx_rtt = hcrx->rtt; 829535c55dfSGerrit Renker rx_info.tfrcrx_p = tfrc_invert_loss_event_rate(hcrx->p_inverse); 8308e138e79SGerrit Renker len = sizeof(rx_info); 8318e138e79SGerrit Renker val = &rx_info; 83288f964dbSArnaldo Carvalho de Melo break; 83388f964dbSArnaldo Carvalho de Melo default: 83488f964dbSArnaldo Carvalho de Melo return -ENOPROTOOPT; 83588f964dbSArnaldo Carvalho de Melo } 83688f964dbSArnaldo Carvalho de Melo 83788f964dbSArnaldo Carvalho de Melo if (put_user(len, optlen) || copy_to_user(optval, val, len)) 83888f964dbSArnaldo Carvalho de Melo return -EFAULT; 83988f964dbSArnaldo Carvalho de Melo 84088f964dbSArnaldo Carvalho de Melo return 0; 84188f964dbSArnaldo Carvalho de Melo } 84288f964dbSArnaldo Carvalho de Melo 84391f0ebf7SArnaldo Carvalho de Melo static struct ccid_operations ccid3 = { 8443dd9a7c3SIan McDonald .ccid_id = DCCPC_CCID3, 84584a97b0aSGerrit Renker .ccid_name = "TCP-Friendly Rate Control", 8467c657876SArnaldo Carvalho de Melo .ccid_owner = THIS_MODULE, 84791f0ebf7SArnaldo Carvalho de Melo .ccid_hc_tx_obj_size = sizeof(struct ccid3_hc_tx_sock), 8487c657876SArnaldo Carvalho de Melo .ccid_hc_tx_init = ccid3_hc_tx_init, 8497c657876SArnaldo Carvalho de Melo .ccid_hc_tx_exit = ccid3_hc_tx_exit, 8507c657876SArnaldo Carvalho de Melo .ccid_hc_tx_send_packet = ccid3_hc_tx_send_packet, 8517c657876SArnaldo Carvalho de Melo .ccid_hc_tx_packet_sent = ccid3_hc_tx_packet_sent, 8527c657876SArnaldo Carvalho de Melo .ccid_hc_tx_packet_recv = ccid3_hc_tx_packet_recv, 8537c657876SArnaldo Carvalho de Melo .ccid_hc_tx_parse_options = ccid3_hc_tx_parse_options, 85491f0ebf7SArnaldo Carvalho de Melo .ccid_hc_rx_obj_size = sizeof(struct ccid3_hc_rx_sock), 8557c657876SArnaldo Carvalho de Melo .ccid_hc_rx_init = ccid3_hc_rx_init, 8567c657876SArnaldo Carvalho de Melo .ccid_hc_rx_exit = ccid3_hc_rx_exit, 8577c657876SArnaldo Carvalho de Melo .ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options, 8587c657876SArnaldo Carvalho de Melo .ccid_hc_rx_packet_recv = ccid3_hc_rx_packet_recv, 8592babe1f6SArnaldo Carvalho de Melo .ccid_hc_rx_get_info = ccid3_hc_rx_get_info, 8602babe1f6SArnaldo Carvalho de Melo .ccid_hc_tx_get_info = ccid3_hc_tx_get_info, 86188f964dbSArnaldo Carvalho de Melo .ccid_hc_rx_getsockopt = ccid3_hc_rx_getsockopt, 86288f964dbSArnaldo Carvalho de Melo .ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt, 8637c657876SArnaldo Carvalho de Melo }; 8647c657876SArnaldo Carvalho de Melo 86556724aa4SGerrit Renker #ifdef CONFIG_IP_DCCP_CCID3_DEBUG 86643264991SGerrit Renker module_param(ccid3_debug, bool, 0644); 8677c657876SArnaldo Carvalho de Melo MODULE_PARM_DESC(ccid3_debug, "Enable debug messages"); 86856724aa4SGerrit Renker #endif 8697c657876SArnaldo Carvalho de Melo 8707c657876SArnaldo Carvalho de Melo static __init int ccid3_module_init(void) 8717c657876SArnaldo Carvalho de Melo { 87234a9e7eaSArnaldo Carvalho de Melo return ccid_register(&ccid3); 8737c657876SArnaldo Carvalho de Melo } 8747c657876SArnaldo Carvalho de Melo module_init(ccid3_module_init); 8757c657876SArnaldo Carvalho de Melo 8767c657876SArnaldo Carvalho de Melo static __exit void ccid3_module_exit(void) 8777c657876SArnaldo Carvalho de Melo { 8787c657876SArnaldo Carvalho de Melo ccid_unregister(&ccid3); 8797c657876SArnaldo Carvalho de Melo } 8807c657876SArnaldo Carvalho de Melo module_exit(ccid3_module_exit); 8817c657876SArnaldo Carvalho de Melo 882e6bccd35SIan McDonald MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>, " 8831f2333aeSArnaldo Carvalho de Melo "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>"); 8847c657876SArnaldo Carvalho de Melo MODULE_DESCRIPTION("DCCP TFRC CCID3 CCID"); 8857c657876SArnaldo Carvalho de Melo MODULE_LICENSE("GPL"); 8867c657876SArnaldo Carvalho de Melo MODULE_ALIAS("net-dccp-ccid-3"); 887