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 */ 527c657876SArnaldo Carvalho de Melo 5317893bc1SGerrit Renker /* 546c08b2cfSGerrit Renker * Compute the initial sending rate X_init in the manner of RFC 3390: 556c08b2cfSGerrit Renker * 566c08b2cfSGerrit Renker * X_init = min(4 * s, max(2 * s, 4380 bytes)) / RTT 576c08b2cfSGerrit Renker * 586c08b2cfSGerrit Renker * Note that RFC 3390 uses MSS, RFC 4342 refers to RFC 3390, and rfc3448bis 596c08b2cfSGerrit Renker * (rev-02) clarifies the use of RFC 3390 with regard to the above formula. 60a21f9f96SGerrit Renker * For consistency with other parts of the code, X_init is scaled by 2^6. 61a21f9f96SGerrit Renker */ 62a21f9f96SGerrit Renker static inline u64 rfc3390_initial_rate(struct sock *sk) 63a21f9f96SGerrit Renker { 646c08b2cfSGerrit Renker const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 65842d1ef1SGerrit Renker const __u32 w_init = clamp_t(__u32, 4380U, 2 * hctx->s, 4 * hctx->s); 66a21f9f96SGerrit Renker 67842d1ef1SGerrit Renker return scaled_div(w_init << 6, hctx->rtt); 68a21f9f96SGerrit Renker } 69a21f9f96SGerrit Renker 70de6f2b59SGerrit Renker /** 71de6f2b59SGerrit Renker * ccid3_update_send_interval - Calculate new t_ipi = s / X_inst 72de6f2b59SGerrit Renker * This respects the granularity of X_inst (64 * bytes/second). 7317893bc1SGerrit Renker */ 74c4e18dadSIlpo Järvinen static void ccid3_update_send_interval(struct ccid3_hc_tx_sock *hctx) 757c657876SArnaldo Carvalho de Melo { 76842d1ef1SGerrit Renker hctx->t_ipi = scaled_div32(((u64)hctx->s) << 6, hctx->x); 7717893bc1SGerrit Renker 78de6f2b59SGerrit Renker ccid3_pr_debug("t_ipi=%u, s=%u, X=%u\n", hctx->t_ipi, 79de6f2b59SGerrit Renker hctx->s, (unsigned)(hctx->x >> 6)); 807c657876SArnaldo Carvalho de Melo } 81aa97efd9SGerrit Renker 82a5358fdcSGerrit Renker static u32 ccid3_hc_tx_idle_rtt(struct ccid3_hc_tx_sock *hctx, ktime_t now) 83a5358fdcSGerrit Renker { 84842d1ef1SGerrit Renker u32 delta = ktime_us_delta(now, hctx->t_last_win_count); 85a5358fdcSGerrit Renker 86842d1ef1SGerrit Renker return delta / hctx->rtt; 87a5358fdcSGerrit Renker } 88a5358fdcSGerrit Renker 89aa97efd9SGerrit Renker /** 90aa97efd9SGerrit Renker * ccid3_hc_tx_update_x - Update allowed sending rate X 91aa97efd9SGerrit Renker * @stamp: most recent time if available - can be left NULL. 92aa97efd9SGerrit Renker * This function tracks draft rfc3448bis, check there for latest details. 935c3fbb6aSGerrit Renker * 941a21e49aSGerrit Renker * Note: X and X_recv are both stored in units of 64 * bytes/second, to support 951a21e49aSGerrit Renker * fine-grained resolution of sending rates. This requires scaling by 2^6 961a21e49aSGerrit Renker * throughout the code. Only X_calc is unscaled (in bytes/second). 971a21e49aSGerrit Renker * 987c657876SArnaldo Carvalho de Melo */ 99aa97efd9SGerrit Renker static void ccid3_hc_tx_update_x(struct sock *sk, ktime_t *stamp) 1007c657876SArnaldo Carvalho de Melo { 10159725dc2SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 102842d1ef1SGerrit Renker u64 min_rate = 2 * hctx->x_recv; 103842d1ef1SGerrit Renker const u64 old_x = hctx->x; 104aa97efd9SGerrit Renker ktime_t now = stamp ? *stamp : ktime_get_real(); 1057c657876SArnaldo Carvalho de Melo 1060c150efbSGerrit Renker /* 1070c150efbSGerrit Renker * Handle IDLE periods: do not reduce below RFC3390 initial sending rate 108a5358fdcSGerrit Renker * when idling [RFC 4342, 5.1]. Definition of idling is from rfc3448bis: 109a5358fdcSGerrit Renker * a sender is idle if it has not sent anything over a 2-RTT-period. 1100c150efbSGerrit Renker * For consistency with X and X_recv, min_rate is also scaled by 2^6. 1110c150efbSGerrit Renker */ 112a5358fdcSGerrit Renker if (ccid3_hc_tx_idle_rtt(hctx, now) >= 2) { 1130c150efbSGerrit Renker min_rate = rfc3390_initial_rate(sk); 114842d1ef1SGerrit Renker min_rate = max(min_rate, 2 * hctx->x_recv); 1150c150efbSGerrit Renker } 1160c150efbSGerrit Renker 117842d1ef1SGerrit Renker if (hctx->p > 0) { 1181a21e49aSGerrit Renker 119842d1ef1SGerrit Renker hctx->x = min(((u64)hctx->x_calc) << 6, min_rate); 120842d1ef1SGerrit Renker hctx->x = max(hctx->x, (((u64)hctx->s) << 6) / TFRC_T_MBI); 121b6ee3d4aSArnaldo Carvalho de Melo 122842d1ef1SGerrit Renker } else if (ktime_us_delta(now, hctx->t_ld) - (s64)hctx->rtt >= 0) { 1231a21e49aSGerrit Renker 124842d1ef1SGerrit Renker hctx->x = min(2 * hctx->x, min_rate); 125842d1ef1SGerrit Renker hctx->x = max(hctx->x, 126842d1ef1SGerrit Renker scaled_div(((u64)hctx->s) << 6, hctx->rtt)); 127842d1ef1SGerrit Renker hctx->t_ld = now; 128ac198ea8SArnaldo Carvalho de Melo } 129a79ef76fSGerrit Renker 130842d1ef1SGerrit Renker if (hctx->x != old_x) { 1311761f7d7SGerrit Renker ccid3_pr_debug("X_prev=%u, X_now=%u, X_calc=%u, " 1321761f7d7SGerrit Renker "X_recv=%u\n", (unsigned)(old_x >> 6), 133842d1ef1SGerrit Renker (unsigned)(hctx->x >> 6), hctx->x_calc, 134842d1ef1SGerrit Renker (unsigned)(hctx->x_recv >> 6)); 1358699be7dSIan McDonald 1361266adeeSGerrit Renker ccid3_update_send_interval(hctx); 1377c657876SArnaldo Carvalho de Melo } 1388699be7dSIan McDonald } 1397c657876SArnaldo Carvalho de Melo 14078ad713dSGerrit Renker /* 14178ad713dSGerrit Renker * Track the mean packet size `s' (cf. RFC 4342, 5.3 and RFC 3448, 4.1) 14278ad713dSGerrit Renker * @len: DCCP packet payload size in bytes 14378ad713dSGerrit Renker */ 14478ad713dSGerrit Renker static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hctx, int len) 14578ad713dSGerrit Renker { 146842d1ef1SGerrit Renker const u16 old_s = hctx->s; 1471266adeeSGerrit Renker 148842d1ef1SGerrit Renker hctx->s = tfrc_ewma(hctx->s, len, 9); 1491266adeeSGerrit Renker 150842d1ef1SGerrit Renker if (hctx->s != old_s) 1511266adeeSGerrit Renker ccid3_update_send_interval(hctx); 15278ad713dSGerrit Renker } 15378ad713dSGerrit Renker 1549f8681dbSGerrit Renker /* 1559f8681dbSGerrit Renker * Update Window Counter using the algorithm from [RFC 4342, 8.1]. 156825de27dSGerrit Renker * As elsewhere, RTT > 0 is assumed by using dccp_sample_rtt(). 1579f8681dbSGerrit Renker */ 1589f8681dbSGerrit Renker static inline void ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock *hctx, 1598132da4dSGerrit Renker ktime_t now) 1609f8681dbSGerrit Renker { 161842d1ef1SGerrit Renker u32 delta = ktime_us_delta(now, hctx->t_last_win_count), 162842d1ef1SGerrit Renker quarter_rtts = (4 * delta) / hctx->rtt; 1639f8681dbSGerrit Renker 1649f8681dbSGerrit Renker if (quarter_rtts > 0) { 165842d1ef1SGerrit Renker hctx->t_last_win_count = now; 166842d1ef1SGerrit Renker hctx->last_win_count += min(quarter_rtts, 5U); 167842d1ef1SGerrit Renker hctx->last_win_count &= 0xF; /* mod 16 */ 1689f8681dbSGerrit Renker } 1699f8681dbSGerrit Renker } 1709f8681dbSGerrit Renker 1717c657876SArnaldo Carvalho de Melo static void ccid3_hc_tx_no_feedback_timer(unsigned long data) 1727c657876SArnaldo Carvalho de Melo { 1737c657876SArnaldo Carvalho de Melo struct sock *sk = (struct sock *)data; 17459725dc2SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 1752a1fda6fSGerrit Renker unsigned long t_nfb = USEC_PER_SEC / 5; 1767c657876SArnaldo Carvalho de Melo 1777c657876SArnaldo Carvalho de Melo bh_lock_sock(sk); 1787c657876SArnaldo Carvalho de Melo if (sock_owned_by_user(sk)) { 1797c657876SArnaldo Carvalho de Melo /* Try again later. */ 1807c657876SArnaldo Carvalho de Melo /* XXX: set some sensible MIB */ 18148e03eeeSGerrit Renker goto restart_timer; 1827c657876SArnaldo Carvalho de Melo } 1837c657876SArnaldo Carvalho de Melo 184d0c05fe4SGerrit Renker ccid3_pr_debug("%s(%p) entry with%s feedback\n", dccp_role(sk), sk, 185d0c05fe4SGerrit Renker hctx->feedback ? "" : "out"); 1867c657876SArnaldo Carvalho de Melo 187d0995e6aSGerrit Renker /* Ignore and do not restart after leaving the established state */ 188d0995e6aSGerrit Renker if ((1 << sk->sk_state) & ~(DCCPF_OPEN | DCCPF_PARTOPEN)) 189d0995e6aSGerrit Renker goto out; 190d0995e6aSGerrit Renker 191d0995e6aSGerrit Renker /* Reset feedback state to "no feedback received" */ 192d0c05fe4SGerrit Renker hctx->feedback = false; 19352515e77SGerrit Renker 19452515e77SGerrit Renker /* 19552515e77SGerrit Renker * Determine new allowed sending rate X as per draft rfc3448bis-00, 4.4 196842d1ef1SGerrit Renker * RTO is 0 if and only if no feedback has been received yet. 19752515e77SGerrit Renker */ 198842d1ef1SGerrit Renker if (hctx->t_rto == 0 || hctx->p == 0) { 19952515e77SGerrit Renker 20052515e77SGerrit Renker /* halve send rate directly */ 201842d1ef1SGerrit Renker hctx->x = max(hctx->x / 2, (((u64)hctx->s) << 6) / TFRC_T_MBI); 2021266adeeSGerrit Renker ccid3_update_send_interval(hctx); 20352515e77SGerrit Renker } else { 2041f2333aeSArnaldo Carvalho de Melo /* 20552515e77SGerrit Renker * Modify the cached value of X_recv 206ff586298SGerrit Renker * 20752515e77SGerrit Renker * If (X_calc > 2 * X_recv) 2087c657876SArnaldo Carvalho de Melo * X_recv = max(X_recv / 2, s / (2 * t_mbi)); 2097c657876SArnaldo Carvalho de Melo * Else 2107c657876SArnaldo Carvalho de Melo * X_recv = X_calc / 4; 2111a21e49aSGerrit Renker * 2121a21e49aSGerrit Renker * Note that X_recv is scaled by 2^6 while X_calc is not 2137c657876SArnaldo Carvalho de Melo */ 214842d1ef1SGerrit Renker BUG_ON(hctx->p && !hctx->x_calc); 2157c657876SArnaldo Carvalho de Melo 216842d1ef1SGerrit Renker if (hctx->x_calc > (hctx->x_recv >> 5)) 217842d1ef1SGerrit Renker hctx->x_recv = 218842d1ef1SGerrit Renker max(hctx->x_recv / 2, 219842d1ef1SGerrit Renker (((__u64)hctx->s) << 6) / (2 * TFRC_T_MBI)); 22052515e77SGerrit Renker else { 221842d1ef1SGerrit Renker hctx->x_recv = hctx->x_calc; 222842d1ef1SGerrit Renker hctx->x_recv <<= 4; 2239e8efc82SGerrit Renker } 224aa97efd9SGerrit Renker ccid3_hc_tx_update_x(sk, NULL); 22552515e77SGerrit Renker } 22652515e77SGerrit Renker ccid3_pr_debug("Reduced X to %llu/64 bytes/sec\n", 227842d1ef1SGerrit Renker (unsigned long long)hctx->x); 22852515e77SGerrit Renker 2296b5e633aSArnaldo Carvalho de Melo /* 23052515e77SGerrit Renker * Set new timeout for the nofeedback timer. 2318a508ac2SGerrit Renker * See comments in packet_recv() regarding the value of t_RTO. 2326b5e633aSArnaldo Carvalho de Melo */ 233842d1ef1SGerrit Renker if (unlikely(hctx->t_rto == 0)) /* no feedback received yet */ 23452515e77SGerrit Renker t_nfb = TFRC_INITIAL_TIMEOUT; 23552515e77SGerrit Renker else 236842d1ef1SGerrit Renker t_nfb = max(hctx->t_rto, 2 * hctx->t_ipi); 2377c657876SArnaldo Carvalho de Melo 23848e03eeeSGerrit Renker restart_timer: 239842d1ef1SGerrit Renker sk_reset_timer(sk, &hctx->no_feedback_timer, 2402a1fda6fSGerrit Renker jiffies + usecs_to_jiffies(t_nfb)); 2417c657876SArnaldo Carvalho de Melo out: 2427c657876SArnaldo Carvalho de Melo bh_unlock_sock(sk); 2437c657876SArnaldo Carvalho de Melo sock_put(sk); 2447c657876SArnaldo Carvalho de Melo } 2457c657876SArnaldo Carvalho de Melo 246f4a66ca4SGerrit Renker /** 247f4a66ca4SGerrit Renker * ccid3_hc_tx_send_packet - Delay-based dequeueing of TX packets 248f4a66ca4SGerrit Renker * @skb: next packet candidate to send on @sk 249f4a66ca4SGerrit Renker * This function uses the convention of ccid_packet_dequeue_eval() and 250f4a66ca4SGerrit Renker * returns a millisecond-delay value between 0 and t_mbi = 64000 msec. 2517da7f456SGerrit Renker */ 2526b57c93dSGerrit Renker static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb) 2537c657876SArnaldo Carvalho de Melo { 2547c657876SArnaldo Carvalho de Melo struct dccp_sock *dp = dccp_sk(sk); 25559725dc2SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 2568132da4dSGerrit Renker ktime_t now = ktime_get_real(); 2578132da4dSGerrit Renker s64 delay; 2587c657876SArnaldo Carvalho de Melo 2597c657876SArnaldo Carvalho de Melo /* 260da335bafSGerrit Renker * This function is called only for Data and DataAck packets. Sending 261da335bafSGerrit Renker * zero-sized Data(Ack)s is theoretically possible, but for congestion 262da335bafSGerrit Renker * control this case is pathological - ignore it. 2637c657876SArnaldo Carvalho de Melo */ 2646b57c93dSGerrit Renker if (unlikely(skb->len == 0)) 265da335bafSGerrit Renker return -EBADMSG; 2667c657876SArnaldo Carvalho de Melo 267d0c05fe4SGerrit Renker if (hctx->s == 0) { 268842d1ef1SGerrit Renker sk_reset_timer(sk, &hctx->no_feedback_timer, (jiffies + 2698109b02bSArnaldo Carvalho de Melo usecs_to_jiffies(TFRC_INITIAL_TIMEOUT))); 270842d1ef1SGerrit Renker hctx->last_win_count = 0; 271842d1ef1SGerrit Renker hctx->t_last_win_count = now; 27290feeb95SGerrit Renker 27390feeb95SGerrit Renker /* Set t_0 for initial packet */ 274842d1ef1SGerrit Renker hctx->t_nom = now; 27530833ffeSGerrit Renker 276842d1ef1SGerrit Renker hctx->s = skb->len; 27730833ffeSGerrit Renker 27830833ffeSGerrit Renker /* 27930833ffeSGerrit Renker * Use initial RTT sample when available: recommended by erratum 28030833ffeSGerrit Renker * to RFC 4342. This implements the initialisation procedure of 28130833ffeSGerrit Renker * draft rfc3448bis, section 4.2. Remember, X is scaled by 2^6. 28230833ffeSGerrit Renker */ 28330833ffeSGerrit Renker if (dp->dccps_syn_rtt) { 28430833ffeSGerrit Renker ccid3_pr_debug("SYN RTT = %uus\n", dp->dccps_syn_rtt); 285842d1ef1SGerrit Renker hctx->rtt = dp->dccps_syn_rtt; 286842d1ef1SGerrit Renker hctx->x = rfc3390_initial_rate(sk); 287842d1ef1SGerrit Renker hctx->t_ld = now; 28830833ffeSGerrit Renker } else { 2893294f202SGerrit Renker /* 2903294f202SGerrit Renker * Sender does not have RTT sample: 2913294f202SGerrit Renker * - set fallback RTT (RFC 4340, 3.4) since a RTT value 2923294f202SGerrit Renker * is needed in several parts (e.g. window counter); 2933294f202SGerrit Renker * - set sending rate X_pps = 1pps as per RFC 3448, 4.2. 2943294f202SGerrit Renker */ 295842d1ef1SGerrit Renker hctx->rtt = DCCP_FALLBACK_RTT; 296842d1ef1SGerrit Renker hctx->x = hctx->s; 297842d1ef1SGerrit Renker hctx->x <<= 6; 29830833ffeSGerrit Renker } 29930833ffeSGerrit Renker ccid3_update_send_interval(hctx); 30030833ffeSGerrit Renker 301d0995e6aSGerrit Renker } else { 302842d1ef1SGerrit Renker delay = ktime_us_delta(hctx->t_nom, now); 3038699be7dSIan McDonald ccid3_pr_debug("delay=%ld\n", (long)delay); 30491cf5a17SGerrit Renker /* 30591cf5a17SGerrit Renker * Scheduling of packet transmissions [RFC 3448, 4.6] 30691cf5a17SGerrit Renker * 30791cf5a17SGerrit Renker * if (t_now > t_nom - delta) 30891cf5a17SGerrit Renker * // send the packet now 30991cf5a17SGerrit Renker * else 31091cf5a17SGerrit Renker * // send the packet in (t_nom - t_now) milliseconds. 31191cf5a17SGerrit Renker */ 312de6f2b59SGerrit Renker if (delay >= TFRC_T_DELTA) 313de6f2b59SGerrit Renker return (u32)delay / USEC_PER_MSEC; 3149f8681dbSGerrit Renker 3158132da4dSGerrit Renker ccid3_hc_tx_update_win_count(hctx, now); 3167c657876SArnaldo Carvalho de Melo } 3177c657876SArnaldo Carvalho de Melo 3187da7f456SGerrit Renker /* prepare to send now (add options etc.) */ 319507d37cfSArnaldo Carvalho de Melo dp->dccps_hc_tx_insert_options = 1; 320842d1ef1SGerrit Renker DCCP_SKB_CB(skb)->dccpd_ccval = hctx->last_win_count; 321e312d100SGerrit Renker 322e312d100SGerrit Renker /* set the nominal send time for the next following packet */ 323842d1ef1SGerrit Renker hctx->t_nom = ktime_add_us(hctx->t_nom, hctx->t_ipi); 324f4a66ca4SGerrit Renker return CCID_PACKET_SEND_AT_ONCE; 3257c657876SArnaldo Carvalho de Melo } 3267c657876SArnaldo Carvalho de Melo 327c506d91dSGerrit Renker static void ccid3_hc_tx_packet_sent(struct sock *sk, unsigned int len) 3287c657876SArnaldo Carvalho de Melo { 32959725dc2SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 3307c657876SArnaldo Carvalho de Melo 33178ad713dSGerrit Renker ccid3_hc_tx_update_s(hctx, len); 33278ad713dSGerrit Renker 333842d1ef1SGerrit Renker if (tfrc_tx_hist_add(&hctx->hist, dccp_sk(sk)->dccps_gss)) 334c5a1ae9aSGerrit Renker DCCP_CRIT("packet history - out of memory!"); 3357c657876SArnaldo Carvalho de Melo } 3367c657876SArnaldo Carvalho de Melo 3377c657876SArnaldo Carvalho de Melo static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) 3387c657876SArnaldo Carvalho de Melo { 33959725dc2SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 34063b3a73bSGerrit Renker struct tfrc_tx_hist_entry *acked; 3410740d49cSArnaldo Carvalho de Melo ktime_t now; 3422a1fda6fSGerrit Renker unsigned long t_nfb; 343ce177ae2SGerrit Renker u32 r_sample; 3441f2333aeSArnaldo Carvalho de Melo 3457c657876SArnaldo Carvalho de Melo /* we are only interested in ACKs */ 3467c657876SArnaldo Carvalho de Melo if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK || 3477c657876SArnaldo Carvalho de Melo DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK)) 3487c657876SArnaldo Carvalho de Melo return; 34963b3a73bSGerrit Renker /* 35063b3a73bSGerrit Renker * Locate the acknowledged packet in the TX history. 35163b3a73bSGerrit Renker * 35263b3a73bSGerrit Renker * Returning "entry not found" here can for instance happen when 35363b3a73bSGerrit Renker * - the host has not sent out anything (e.g. a passive server), 35463b3a73bSGerrit Renker * - the Ack is outdated (packet with higher Ack number was received), 35563b3a73bSGerrit Renker * - it is a bogus Ack (for a packet not sent on this connection). 35663b3a73bSGerrit Renker */ 35763b3a73bSGerrit Renker acked = tfrc_tx_hist_find_entry(hctx->hist, dccp_hdr_ack_seq(skb)); 35863b3a73bSGerrit Renker if (acked == NULL) 3597c657876SArnaldo Carvalho de Melo return; 36063b3a73bSGerrit Renker /* For the sake of RTT sampling, ignore/remove all older entries */ 36163b3a73bSGerrit Renker tfrc_tx_hist_purge(&acked->next); 36263b3a73bSGerrit Renker 36363b3a73bSGerrit Renker /* Update the moving average for the RTT estimate (RFC 3448, 4.3) */ 36463b3a73bSGerrit Renker now = ktime_get_real(); 36563b3a73bSGerrit Renker r_sample = dccp_sample_rtt(sk, ktime_us_delta(now, acked->stamp)); 36663b3a73bSGerrit Renker hctx->rtt = tfrc_ewma(hctx->rtt, r_sample, 9); 3677c657876SArnaldo Carvalho de Melo 3681a21e49aSGerrit Renker /* 369d8d1252fSGerrit Renker * Update allowed sending rate X as per draft rfc3448bis-00, 4.2/3 370d8d1252fSGerrit Renker */ 371d0c05fe4SGerrit Renker if (!hctx->feedback) { 372d0c05fe4SGerrit Renker hctx->feedback = true; 373d8d1252fSGerrit Renker 374842d1ef1SGerrit Renker if (hctx->t_rto == 0) { 375d8d1252fSGerrit Renker /* 376d8d1252fSGerrit Renker * Initial feedback packet: Larger Initial Windows (4.2) 3771a21e49aSGerrit Renker */ 378842d1ef1SGerrit Renker hctx->x = rfc3390_initial_rate(sk); 379842d1ef1SGerrit Renker hctx->t_ld = now; 380a79ef76fSGerrit Renker 3811266adeeSGerrit Renker ccid3_update_send_interval(hctx); 3825c3fbb6aSGerrit Renker 383d8d1252fSGerrit Renker goto done_computing_x; 384842d1ef1SGerrit Renker } else if (hctx->p == 0) { 385d8d1252fSGerrit Renker /* 386d8d1252fSGerrit Renker * First feedback after nofeedback timer expiry (4.3) 387d8d1252fSGerrit Renker */ 388d8d1252fSGerrit Renker goto done_computing_x; 389d8d1252fSGerrit Renker } 390d8d1252fSGerrit Renker } 3915c3fbb6aSGerrit Renker 392ff586298SGerrit Renker /* Update sending rate (step 4 of [RFC 3448, 4.3]) */ 393842d1ef1SGerrit Renker if (hctx->p > 0) 394842d1ef1SGerrit Renker hctx->x_calc = tfrc_calc_x(hctx->s, hctx->rtt, hctx->p); 395aa97efd9SGerrit Renker ccid3_hc_tx_update_x(sk, &now); 3967c657876SArnaldo Carvalho de Melo 397d8d1252fSGerrit Renker done_computing_x: 3987dfee1a9SGerrit Renker ccid3_pr_debug("%s(%p), RTT=%uus (sample=%uus), s=%u, " 3998109b02bSArnaldo Carvalho de Melo "p=%u, X_calc=%u, X_recv=%u, X=%u\n", 400842d1ef1SGerrit Renker dccp_role(sk), sk, hctx->rtt, r_sample, 401842d1ef1SGerrit Renker hctx->s, hctx->p, hctx->x_calc, 402842d1ef1SGerrit Renker (unsigned)(hctx->x_recv >> 6), 403842d1ef1SGerrit Renker (unsigned)(hctx->x >> 6)); 4047c657876SArnaldo Carvalho de Melo 4057c657876SArnaldo Carvalho de Melo /* unschedule no feedback timer */ 406842d1ef1SGerrit Renker sk_stop_timer(sk, &hctx->no_feedback_timer); 4077c657876SArnaldo Carvalho de Melo 408c530cfb1SArnaldo Carvalho de Melo /* 4098109b02bSArnaldo Carvalho de Melo * As we have calculated new ipi, delta, t_nom it is possible 4108109b02bSArnaldo Carvalho de Melo * that we now can send a packet, so wake up dccp_wait_for_ccid 411c530cfb1SArnaldo Carvalho de Melo */ 412c530cfb1SArnaldo Carvalho de Melo sk->sk_write_space(sk); 4138c60f3faSArnaldo Carvalho de Melo 4148a508ac2SGerrit Renker /* 4158a508ac2SGerrit Renker * Update timeout interval for the nofeedback timer. 4168a508ac2SGerrit Renker * We use a configuration option to increase the lower bound. 4178109b02bSArnaldo Carvalho de Melo * This can help avoid triggering the nofeedback timer too 4188109b02bSArnaldo Carvalho de Melo * often ('spinning') on LANs with small RTTs. 4198a508ac2SGerrit Renker */ 420842d1ef1SGerrit Renker hctx->t_rto = max_t(u32, 4 * hctx->rtt, (CONFIG_IP_DCCP_CCID3_RTO * 4215bd370a6SGerrit Renker (USEC_PER_SEC / 1000))); 4221f2333aeSArnaldo Carvalho de Melo /* 4231f2333aeSArnaldo Carvalho de Melo * Schedule no feedback timer to expire in 4248a508ac2SGerrit Renker * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi) 4251f2333aeSArnaldo Carvalho de Melo */ 426842d1ef1SGerrit Renker t_nfb = max(hctx->t_rto, 2 * hctx->t_ipi); 4277c657876SArnaldo Carvalho de Melo 428a9672411SGerrit Renker ccid3_pr_debug("%s(%p), Scheduled no feedback timer to " 4298109b02bSArnaldo Carvalho de Melo "expire in %lu jiffies (%luus)\n", 430842d1ef1SGerrit Renker dccp_role(sk), sk, usecs_to_jiffies(t_nfb), t_nfb); 4317c657876SArnaldo Carvalho de Melo 432842d1ef1SGerrit Renker sk_reset_timer(sk, &hctx->no_feedback_timer, 4332a1fda6fSGerrit Renker jiffies + usecs_to_jiffies(t_nfb)); 4347c657876SArnaldo Carvalho de Melo } 4357c657876SArnaldo Carvalho de Melo 4363306c781SGerrit Renker static int ccid3_hc_tx_parse_options(struct sock *sk, u8 packet_type, 4373306c781SGerrit Renker u8 option, u8 *optval, u8 optlen) 4387c657876SArnaldo Carvalho de Melo { 43959725dc2SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 44076fd1e87SGerrit Renker __be32 opt_val; 4417c657876SArnaldo Carvalho de Melo 4427c657876SArnaldo Carvalho de Melo switch (option) { 44347a61e7bSGerrit Renker case TFRC_OPT_RECEIVE_RATE: 4447c657876SArnaldo Carvalho de Melo case TFRC_OPT_LOSS_EVENT_RATE: 4453306c781SGerrit Renker /* Must be ignored on Data packets, cf. RFC 4342 8.3 and 8.5 */ 4463306c781SGerrit Renker if (packet_type == DCCP_PKT_DATA) 4473306c781SGerrit Renker break; 4483306c781SGerrit Renker if (unlikely(optlen != 4)) { 44947a61e7bSGerrit Renker DCCP_WARN("%s(%p), invalid len %d for %u\n", 4503306c781SGerrit Renker dccp_role(sk), sk, optlen, option); 45147a61e7bSGerrit Renker return -EINVAL; 4527c657876SArnaldo Carvalho de Melo } 4533306c781SGerrit Renker opt_val = ntohl(get_unaligned((__be32 *)optval)); 4547c657876SArnaldo Carvalho de Melo 45547a61e7bSGerrit Renker if (option == TFRC_OPT_RECEIVE_RATE) { 456ce177ae2SGerrit Renker /* Receive Rate is kept in units of 64 bytes/second */ 457ce177ae2SGerrit Renker hctx->x_recv = opt_val; 458ce177ae2SGerrit Renker hctx->x_recv <<= 6; 459ce177ae2SGerrit Renker 46047a61e7bSGerrit Renker ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n", 46147a61e7bSGerrit Renker dccp_role(sk), sk, opt_val); 46247a61e7bSGerrit Renker } else { 463ce177ae2SGerrit Renker /* Update the fixpoint Loss Event Rate fraction */ 464ce177ae2SGerrit Renker hctx->p = tfrc_invert_loss_event_rate(opt_val); 465ce177ae2SGerrit Renker 46647a61e7bSGerrit Renker ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n", 46747a61e7bSGerrit Renker dccp_role(sk), sk, opt_val); 46847a61e7bSGerrit Renker } 46947a61e7bSGerrit Renker } 47047a61e7bSGerrit Renker return 0; 4717c657876SArnaldo Carvalho de Melo } 4727c657876SArnaldo Carvalho de Melo 47391f0ebf7SArnaldo Carvalho de Melo static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk) 4747c657876SArnaldo Carvalho de Melo { 47591f0ebf7SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid_priv(ccid); 4767c657876SArnaldo Carvalho de Melo 477842d1ef1SGerrit Renker hctx->hist = NULL; 478842d1ef1SGerrit Renker setup_timer(&hctx->no_feedback_timer, 479b24b8a24SPavel Emelyanov ccid3_hc_tx_no_feedback_timer, (unsigned long)sk); 4807c657876SArnaldo Carvalho de Melo return 0; 4817c657876SArnaldo Carvalho de Melo } 4827c657876SArnaldo Carvalho de Melo 4837c657876SArnaldo Carvalho de Melo static void ccid3_hc_tx_exit(struct sock *sk) 4847c657876SArnaldo Carvalho de Melo { 48559725dc2SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 4867c657876SArnaldo Carvalho de Melo 487842d1ef1SGerrit Renker sk_stop_timer(sk, &hctx->no_feedback_timer); 488842d1ef1SGerrit Renker tfrc_tx_hist_purge(&hctx->hist); 4897c657876SArnaldo Carvalho de Melo } 4907c657876SArnaldo Carvalho de Melo 4919bf17475SGerrit Renker static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info) 4929bf17475SGerrit Renker { 493b2e317f4SGerrit Renker info->tcpi_rto = ccid3_hc_tx_sk(sk)->t_rto; 494b2e317f4SGerrit Renker info->tcpi_rtt = ccid3_hc_tx_sk(sk)->rtt; 4959bf17475SGerrit Renker } 4969bf17475SGerrit Renker 4979bf17475SGerrit Renker static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len, 4989bf17475SGerrit Renker u32 __user *optval, int __user *optlen) 4999bf17475SGerrit Renker { 500b2e317f4SGerrit Renker const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 501842d1ef1SGerrit Renker struct tfrc_tx_info tfrc; 5029bf17475SGerrit Renker const void *val; 5039bf17475SGerrit Renker 5049bf17475SGerrit Renker switch (optname) { 5059bf17475SGerrit Renker case DCCP_SOCKOPT_CCID_TX_INFO: 506842d1ef1SGerrit Renker if (len < sizeof(tfrc)) 5079bf17475SGerrit Renker return -EINVAL; 508842d1ef1SGerrit Renker tfrc.tfrctx_x = hctx->x; 509842d1ef1SGerrit Renker tfrc.tfrctx_x_recv = hctx->x_recv; 510842d1ef1SGerrit Renker tfrc.tfrctx_x_calc = hctx->x_calc; 511842d1ef1SGerrit Renker tfrc.tfrctx_rtt = hctx->rtt; 512842d1ef1SGerrit Renker tfrc.tfrctx_p = hctx->p; 513842d1ef1SGerrit Renker tfrc.tfrctx_rto = hctx->t_rto; 514842d1ef1SGerrit Renker tfrc.tfrctx_ipi = hctx->t_ipi; 515842d1ef1SGerrit Renker len = sizeof(tfrc); 516842d1ef1SGerrit Renker val = &tfrc; 5179bf17475SGerrit Renker break; 5189bf17475SGerrit Renker default: 5199bf17475SGerrit Renker return -ENOPROTOOPT; 5209bf17475SGerrit Renker } 5219bf17475SGerrit Renker 5229bf17475SGerrit Renker if (put_user(len, optlen) || copy_to_user(optval, val, len)) 5239bf17475SGerrit Renker return -EFAULT; 5249bf17475SGerrit Renker 5259bf17475SGerrit Renker return 0; 5269bf17475SGerrit Renker } 5279bf17475SGerrit Renker 5289bf17475SGerrit Renker /* 5299bf17475SGerrit Renker * Receiver Half-Connection Routines 5309bf17475SGerrit Renker */ 531b84a2189SArnaldo Carvalho de Melo static void ccid3_hc_rx_send_feedback(struct sock *sk, 532b84a2189SArnaldo Carvalho de Melo const struct sk_buff *skb, 533b84a2189SArnaldo Carvalho de Melo enum ccid3_fback_type fbtype) 5347c657876SArnaldo Carvalho de Melo { 53559725dc2SArnaldo Carvalho de Melo struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 5367c657876SArnaldo Carvalho de Melo struct dccp_sock *dp = dccp_sk(sk); 537d0995e6aSGerrit Renker ktime_t now = ktime_get_real(); 538b84a2189SArnaldo Carvalho de Melo s64 delta = 0; 5397c657876SArnaldo Carvalho de Melo 540b84a2189SArnaldo Carvalho de Melo switch (fbtype) { 541b84a2189SArnaldo Carvalho de Melo case CCID3_FBACK_INITIAL: 542842d1ef1SGerrit Renker hcrx->x_recv = 0; 543842d1ef1SGerrit Renker hcrx->p_inverse = ~0U; /* see RFC 4342, 8.5 */ 5447c657876SArnaldo Carvalho de Melo break; 545b84a2189SArnaldo Carvalho de Melo case CCID3_FBACK_PARAM_CHANGE: 5462f3e3bbaSGerrit Renker if (unlikely(hcrx->feedback == CCID3_FBACK_NONE)) { 547d20ed95fSGerrit Renker /* 548d20ed95fSGerrit Renker * rfc3448bis-06, 6.3.1: First packet(s) lost or marked 549d20ed95fSGerrit Renker * FIXME: in rfc3448bis the receiver returns X_recv=0 550d20ed95fSGerrit Renker * here as it normally would in the first feedback packet. 551d20ed95fSGerrit Renker * However this is not possible yet, since the code still 552d20ed95fSGerrit Renker * uses RFC 3448, i.e. 553d20ed95fSGerrit Renker * If (p > 0) 554d20ed95fSGerrit Renker * Calculate X_calc using the TCP throughput equation. 555d20ed95fSGerrit Renker * X = max(min(X_calc, 2*X_recv), s/t_mbi); 556d20ed95fSGerrit Renker * would bring X down to s/t_mbi. That is why we return 557d20ed95fSGerrit Renker * X_recv according to rfc3448bis-06 for the moment. 558d20ed95fSGerrit Renker */ 55934a081beSGerrit Renker u32 rtt = hcrx->rtt ? : DCCP_FALLBACK_RTT, 56034a081beSGerrit Renker s = tfrc_rx_hist_packet_size(&hcrx->hist); 561d20ed95fSGerrit Renker 562d20ed95fSGerrit Renker hcrx->x_recv = scaled_div32(s, 2 * rtt); 563d20ed95fSGerrit Renker break; 564d20ed95fSGerrit Renker } 565b84a2189SArnaldo Carvalho de Melo /* 566b84a2189SArnaldo Carvalho de Melo * When parameters change (new loss or p > p_prev), we do not 567b84a2189SArnaldo Carvalho de Melo * have a reliable estimate for R_m of [RFC 3448, 6.2] and so 568b84a2189SArnaldo Carvalho de Melo * need to reuse the previous value of X_recv. However, when 569b84a2189SArnaldo Carvalho de Melo * X_recv was 0 (due to early loss), this would kill X down to 570b84a2189SArnaldo Carvalho de Melo * s/t_mbi (i.e. one packet in 64 seconds). 571b84a2189SArnaldo Carvalho de Melo * To avoid such drastic reduction, we approximate X_recv as 572b84a2189SArnaldo Carvalho de Melo * the number of bytes since last feedback. 573b84a2189SArnaldo Carvalho de Melo * This is a safe fallback, since X is bounded above by X_calc. 574b84a2189SArnaldo Carvalho de Melo */ 575842d1ef1SGerrit Renker if (hcrx->x_recv > 0) 576b84a2189SArnaldo Carvalho de Melo break; 577b84a2189SArnaldo Carvalho de Melo /* fall through */ 578b84a2189SArnaldo Carvalho de Melo case CCID3_FBACK_PERIODIC: 579842d1ef1SGerrit Renker delta = ktime_us_delta(now, hcrx->tstamp_last_feedback); 580b84a2189SArnaldo Carvalho de Melo if (delta <= 0) 581b84a2189SArnaldo Carvalho de Melo DCCP_BUG("delta (%ld) <= 0", (long)delta); 582b84a2189SArnaldo Carvalho de Melo else 58334a081beSGerrit Renker hcrx->x_recv = scaled_div32(hcrx->hist.bytes_recvd, delta); 5847c657876SArnaldo Carvalho de Melo break; 585b84a2189SArnaldo Carvalho de Melo default: 5867c657876SArnaldo Carvalho de Melo return; 5877c657876SArnaldo Carvalho de Melo } 5887c657876SArnaldo Carvalho de Melo 589842d1ef1SGerrit Renker ccid3_pr_debug("Interval %ldusec, X_recv=%u, 1/p=%u\n", 590842d1ef1SGerrit Renker (long)delta, hcrx->x_recv, hcrx->p_inverse); 5917c657876SArnaldo Carvalho de Melo 592842d1ef1SGerrit Renker hcrx->tstamp_last_feedback = now; 593842d1ef1SGerrit Renker hcrx->last_counter = dccp_hdr(skb)->dccph_ccval; 59434a081beSGerrit Renker hcrx->hist.bytes_recvd = 0; 5952f3e3bbaSGerrit Renker hcrx->feedback = fbtype; 5967c657876SArnaldo Carvalho de Melo 597507d37cfSArnaldo Carvalho de Melo dp->dccps_hc_rx_insert_options = 1; 5987c657876SArnaldo Carvalho de Melo dccp_send_ack(sk); 5997c657876SArnaldo Carvalho de Melo } 6007c657876SArnaldo Carvalho de Melo 6012d0817d1SArnaldo Carvalho de Melo static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb) 6027c657876SArnaldo Carvalho de Melo { 603b2e317f4SGerrit Renker const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 60460fe62e7SAndrea Bittau __be32 x_recv, pinv; 6057c657876SArnaldo Carvalho de Melo 60659d203f9SArnaldo Carvalho de Melo if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN)) 6072d0817d1SArnaldo Carvalho de Melo return 0; 6087c657876SArnaldo Carvalho de Melo 6094fded33bSArnaldo Carvalho de Melo if (dccp_packet_without_ack(skb)) 6102d0817d1SArnaldo Carvalho de Melo return 0; 6114fded33bSArnaldo Carvalho de Melo 612842d1ef1SGerrit Renker x_recv = htonl(hcrx->x_recv); 613842d1ef1SGerrit Renker pinv = htonl(hcrx->p_inverse); 6142d0817d1SArnaldo Carvalho de Melo 615385ac2e3SGerrit Renker if (dccp_insert_option(sk, skb, TFRC_OPT_LOSS_EVENT_RATE, 6162d0817d1SArnaldo Carvalho de Melo &pinv, sizeof(pinv)) || 6174fded33bSArnaldo Carvalho de Melo dccp_insert_option(sk, skb, TFRC_OPT_RECEIVE_RATE, 6182d0817d1SArnaldo Carvalho de Melo &x_recv, sizeof(x_recv))) 6192d0817d1SArnaldo Carvalho de Melo return -1; 6202d0817d1SArnaldo Carvalho de Melo 6212d0817d1SArnaldo Carvalho de Melo return 0; 6227c657876SArnaldo Carvalho de Melo } 6237c657876SArnaldo Carvalho de Melo 624954c2db8SGerrit Renker /** ccid3_first_li - Implements [RFC 3448, 6.3.1] 625954c2db8SGerrit Renker * 626954c2db8SGerrit Renker * Determine the length of the first loss interval via inverse lookup. 627954c2db8SGerrit Renker * Assume that X_recv can be computed by the throughput equation 628954c2db8SGerrit Renker * s 629954c2db8SGerrit Renker * X_recv = -------- 630954c2db8SGerrit Renker * R * fval 631954c2db8SGerrit Renker * Find some p such that f(p) = fval; return 1/p (scaled). 632954c2db8SGerrit Renker */ 633954c2db8SGerrit Renker static u32 ccid3_first_li(struct sock *sk) 634954c2db8SGerrit Renker { 635954c2db8SGerrit Renker struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 63634a081beSGerrit Renker u32 x_recv, p, delta, 63734a081beSGerrit Renker s = tfrc_rx_hist_packet_size(&hcrx->hist); 638954c2db8SGerrit Renker u64 fval; 639954c2db8SGerrit Renker 640d20ed95fSGerrit Renker /* 641d20ed95fSGerrit Renker * rfc3448bis-06, 6.3.1: First data packet(s) are marked or lost. Set p 642d20ed95fSGerrit Renker * to give the equivalent of X_target = s/(2*R). Thus fval = 2 and so p 643d20ed95fSGerrit Renker * is about 20.64%. This yields an interval length of 4.84 (rounded up). 644d20ed95fSGerrit Renker */ 6452f3e3bbaSGerrit Renker if (unlikely(hcrx->feedback == CCID3_FBACK_NONE)) 646d20ed95fSGerrit Renker return 5; 647d20ed95fSGerrit Renker 648842d1ef1SGerrit Renker if (hcrx->rtt == 0) { 649954c2db8SGerrit Renker DCCP_WARN("No RTT estimate available, using fallback RTT\n"); 650842d1ef1SGerrit Renker hcrx->rtt = DCCP_FALLBACK_RTT; 651954c2db8SGerrit Renker } 652954c2db8SGerrit Renker 653842d1ef1SGerrit Renker delta = ktime_to_us(net_timedelta(hcrx->tstamp_last_feedback)); 65434a081beSGerrit Renker x_recv = scaled_div32(hcrx->hist.bytes_recvd, delta); 655954c2db8SGerrit Renker if (x_recv == 0) { /* would also trigger divide-by-zero */ 656954c2db8SGerrit Renker DCCP_WARN("X_recv==0\n"); 657842d1ef1SGerrit Renker if (hcrx->x_recv == 0) { 658954c2db8SGerrit Renker DCCP_BUG("stored value of X_recv is zero"); 659954c2db8SGerrit Renker return ~0U; 660954c2db8SGerrit Renker } 661842d1ef1SGerrit Renker x_recv = hcrx->x_recv; 662954c2db8SGerrit Renker } 663954c2db8SGerrit Renker 66434a081beSGerrit Renker fval = scaled_div32(scaled_div(s, hcrx->rtt), x_recv); 665954c2db8SGerrit Renker p = tfrc_calc_x_reverse_lookup(fval); 666954c2db8SGerrit Renker 667954c2db8SGerrit Renker ccid3_pr_debug("%s(%p), receive rate=%u bytes/s, implied " 668954c2db8SGerrit Renker "loss rate=%u\n", dccp_role(sk), sk, x_recv, p); 669954c2db8SGerrit Renker 670954c2db8SGerrit Renker return p == 0 ? ~0U : scaled_div(1, p); 671954c2db8SGerrit Renker } 672954c2db8SGerrit Renker 6737c657876SArnaldo Carvalho de Melo static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) 6747c657876SArnaldo Carvalho de Melo { 67559725dc2SArnaldo Carvalho de Melo struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 676b84a2189SArnaldo Carvalho de Melo enum ccid3_fback_type do_feedback = CCID3_FBACK_NONE; 6775b5d0e70SGerrit Renker const u64 ndp = dccp_sk(sk)->dccps_options_received.dccpor_ndp; 678b84a2189SArnaldo Carvalho de Melo const bool is_data_packet = dccp_data_packet(skb); 6791f2333aeSArnaldo Carvalho de Melo 680d20ed95fSGerrit Renker /* 681d20ed95fSGerrit Renker * Perform loss detection and handle pending losses 682d20ed95fSGerrit Renker */ 683d20ed95fSGerrit Renker if (tfrc_rx_handle_loss(&hcrx->hist, &hcrx->li_hist, 684d20ed95fSGerrit Renker skb, ndp, ccid3_first_li, sk)) { 685d20ed95fSGerrit Renker do_feedback = CCID3_FBACK_PARAM_CHANGE; 686d20ed95fSGerrit Renker goto done_receiving; 687d20ed95fSGerrit Renker } 688d20ed95fSGerrit Renker 6892f3e3bbaSGerrit Renker if (unlikely(hcrx->feedback == CCID3_FBACK_NONE)) { 6902f3e3bbaSGerrit Renker if (is_data_packet) 691b84a2189SArnaldo Carvalho de Melo do_feedback = CCID3_FBACK_INITIAL; 692b84a2189SArnaldo Carvalho de Melo goto update_records; 6937c657876SArnaldo Carvalho de Melo } 6947c657876SArnaldo Carvalho de Melo 695842d1ef1SGerrit Renker if (tfrc_rx_hist_loss_pending(&hcrx->hist)) 696b552c623SGerrit Renker return; /* done receiving */ 697b84a2189SArnaldo Carvalho de Melo 698b84a2189SArnaldo Carvalho de Melo /* 699b84a2189SArnaldo Carvalho de Melo * Handle data packets: RTT sampling and monitoring p 700b84a2189SArnaldo Carvalho de Melo */ 701b84a2189SArnaldo Carvalho de Melo if (unlikely(!is_data_packet)) 702b84a2189SArnaldo Carvalho de Melo goto update_records; 703b84a2189SArnaldo Carvalho de Melo 704842d1ef1SGerrit Renker if (!tfrc_lh_is_initialised(&hcrx->li_hist)) { 705842d1ef1SGerrit Renker const u32 sample = tfrc_rx_hist_sample_rtt(&hcrx->hist, skb); 706b84a2189SArnaldo Carvalho de Melo /* 707b84a2189SArnaldo Carvalho de Melo * Empty loss history: no loss so far, hence p stays 0. 708b84a2189SArnaldo Carvalho de Melo * Sample RTT values, since an RTT estimate is required for the 709b84a2189SArnaldo Carvalho de Melo * computation of p when the first loss occurs; RFC 3448, 6.3.1. 710b84a2189SArnaldo Carvalho de Melo */ 711b84a2189SArnaldo Carvalho de Melo if (sample != 0) 712842d1ef1SGerrit Renker hcrx->rtt = tfrc_ewma(hcrx->rtt, sample, 9); 713b84a2189SArnaldo Carvalho de Melo } 714b84a2189SArnaldo Carvalho de Melo /* 715b84a2189SArnaldo Carvalho de Melo * Check if the periodic once-per-RTT feedback is due; RFC 4342, 10.3 716b84a2189SArnaldo Carvalho de Melo */ 717842d1ef1SGerrit Renker if (SUB16(dccp_hdr(skb)->dccph_ccval, hcrx->last_counter) > 3) 718b84a2189SArnaldo Carvalho de Melo do_feedback = CCID3_FBACK_PERIODIC; 719b84a2189SArnaldo Carvalho de Melo 720b84a2189SArnaldo Carvalho de Melo update_records: 721842d1ef1SGerrit Renker tfrc_rx_hist_add_packet(&hcrx->hist, skb, ndp); 722b84a2189SArnaldo Carvalho de Melo 723954c2db8SGerrit Renker done_receiving: 724b84a2189SArnaldo Carvalho de Melo if (do_feedback) 725b84a2189SArnaldo Carvalho de Melo ccid3_hc_rx_send_feedback(sk, skb, do_feedback); 7267c657876SArnaldo Carvalho de Melo } 7277c657876SArnaldo Carvalho de Melo 72891f0ebf7SArnaldo Carvalho de Melo static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk) 7297c657876SArnaldo Carvalho de Melo { 73091f0ebf7SArnaldo Carvalho de Melo struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid); 7317c657876SArnaldo Carvalho de Melo 732842d1ef1SGerrit Renker tfrc_lh_init(&hcrx->li_hist); 73324b8d343SGerrit Renker return tfrc_rx_hist_init(&hcrx->hist, sk); 7347c657876SArnaldo Carvalho de Melo } 7357c657876SArnaldo Carvalho de Melo 7367c657876SArnaldo Carvalho de Melo static void ccid3_hc_rx_exit(struct sock *sk) 7377c657876SArnaldo Carvalho de Melo { 73859725dc2SArnaldo Carvalho de Melo struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 7397c657876SArnaldo Carvalho de Melo 740842d1ef1SGerrit Renker tfrc_rx_hist_purge(&hcrx->hist); 741842d1ef1SGerrit Renker tfrc_lh_cleanup(&hcrx->li_hist); 7427c657876SArnaldo Carvalho de Melo } 7437c657876SArnaldo Carvalho de Melo 7442babe1f6SArnaldo Carvalho de Melo static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info) 7452babe1f6SArnaldo Carvalho de Melo { 7462babe1f6SArnaldo Carvalho de Melo info->tcpi_options |= TCPI_OPT_TIMESTAMPS; 747b2e317f4SGerrit Renker info->tcpi_rcv_rtt = ccid3_hc_rx_sk(sk)->rtt; 7482babe1f6SArnaldo Carvalho de Melo } 7492babe1f6SArnaldo Carvalho de Melo 75088f964dbSArnaldo Carvalho de Melo static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len, 75188f964dbSArnaldo Carvalho de Melo u32 __user *optval, int __user *optlen) 75288f964dbSArnaldo Carvalho de Melo { 753b2e317f4SGerrit Renker const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 7548e138e79SGerrit Renker struct tfrc_rx_info rx_info; 75588f964dbSArnaldo Carvalho de Melo const void *val; 75688f964dbSArnaldo Carvalho de Melo 75788f964dbSArnaldo Carvalho de Melo switch (optname) { 75888f964dbSArnaldo Carvalho de Melo case DCCP_SOCKOPT_CCID_RX_INFO: 7598e138e79SGerrit Renker if (len < sizeof(rx_info)) 76088f964dbSArnaldo Carvalho de Melo return -EINVAL; 761842d1ef1SGerrit Renker rx_info.tfrcrx_x_recv = hcrx->x_recv; 762842d1ef1SGerrit Renker rx_info.tfrcrx_rtt = hcrx->rtt; 763535c55dfSGerrit Renker rx_info.tfrcrx_p = tfrc_invert_loss_event_rate(hcrx->p_inverse); 7648e138e79SGerrit Renker len = sizeof(rx_info); 7658e138e79SGerrit Renker val = &rx_info; 76688f964dbSArnaldo Carvalho de Melo break; 76788f964dbSArnaldo Carvalho de Melo default: 76888f964dbSArnaldo Carvalho de Melo return -ENOPROTOOPT; 76988f964dbSArnaldo Carvalho de Melo } 77088f964dbSArnaldo Carvalho de Melo 77188f964dbSArnaldo Carvalho de Melo if (put_user(len, optlen) || copy_to_user(optval, val, len)) 77288f964dbSArnaldo Carvalho de Melo return -EFAULT; 77388f964dbSArnaldo Carvalho de Melo 77488f964dbSArnaldo Carvalho de Melo return 0; 77588f964dbSArnaldo Carvalho de Melo } 77688f964dbSArnaldo Carvalho de Melo 77791f0ebf7SArnaldo Carvalho de Melo static struct ccid_operations ccid3 = { 7783dd9a7c3SIan McDonald .ccid_id = DCCPC_CCID3, 77984a97b0aSGerrit Renker .ccid_name = "TCP-Friendly Rate Control", 7807c657876SArnaldo Carvalho de Melo .ccid_owner = THIS_MODULE, 78191f0ebf7SArnaldo Carvalho de Melo .ccid_hc_tx_obj_size = sizeof(struct ccid3_hc_tx_sock), 7827c657876SArnaldo Carvalho de Melo .ccid_hc_tx_init = ccid3_hc_tx_init, 7837c657876SArnaldo Carvalho de Melo .ccid_hc_tx_exit = ccid3_hc_tx_exit, 7847c657876SArnaldo Carvalho de Melo .ccid_hc_tx_send_packet = ccid3_hc_tx_send_packet, 7857c657876SArnaldo Carvalho de Melo .ccid_hc_tx_packet_sent = ccid3_hc_tx_packet_sent, 7867c657876SArnaldo Carvalho de Melo .ccid_hc_tx_packet_recv = ccid3_hc_tx_packet_recv, 7877c657876SArnaldo Carvalho de Melo .ccid_hc_tx_parse_options = ccid3_hc_tx_parse_options, 78891f0ebf7SArnaldo Carvalho de Melo .ccid_hc_rx_obj_size = sizeof(struct ccid3_hc_rx_sock), 7897c657876SArnaldo Carvalho de Melo .ccid_hc_rx_init = ccid3_hc_rx_init, 7907c657876SArnaldo Carvalho de Melo .ccid_hc_rx_exit = ccid3_hc_rx_exit, 7917c657876SArnaldo Carvalho de Melo .ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options, 7927c657876SArnaldo Carvalho de Melo .ccid_hc_rx_packet_recv = ccid3_hc_rx_packet_recv, 7932babe1f6SArnaldo Carvalho de Melo .ccid_hc_rx_get_info = ccid3_hc_rx_get_info, 7942babe1f6SArnaldo Carvalho de Melo .ccid_hc_tx_get_info = ccid3_hc_tx_get_info, 79588f964dbSArnaldo Carvalho de Melo .ccid_hc_rx_getsockopt = ccid3_hc_rx_getsockopt, 79688f964dbSArnaldo Carvalho de Melo .ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt, 7977c657876SArnaldo Carvalho de Melo }; 7987c657876SArnaldo Carvalho de Melo 79956724aa4SGerrit Renker #ifdef CONFIG_IP_DCCP_CCID3_DEBUG 80043264991SGerrit Renker module_param(ccid3_debug, bool, 0644); 8017c657876SArnaldo Carvalho de Melo MODULE_PARM_DESC(ccid3_debug, "Enable debug messages"); 80256724aa4SGerrit Renker #endif 8037c657876SArnaldo Carvalho de Melo 8047c657876SArnaldo Carvalho de Melo static __init int ccid3_module_init(void) 8057c657876SArnaldo Carvalho de Melo { 806f76fd327SGerrit Renker struct timespec tp; 807f76fd327SGerrit Renker 808f76fd327SGerrit Renker /* 809f76fd327SGerrit Renker * Without a fine-grained clock resolution, RTTs/X_recv are not sampled 810f76fd327SGerrit Renker * correctly and feedback is sent either too early or too late. 811f76fd327SGerrit Renker */ 812f76fd327SGerrit Renker hrtimer_get_res(CLOCK_MONOTONIC, &tp); 813f76fd327SGerrit Renker if (tp.tv_sec || tp.tv_nsec > DCCP_TIME_RESOLUTION * NSEC_PER_USEC) { 814f76fd327SGerrit Renker printk(KERN_ERR "%s: Timer too coarse (%ld usec), need %u-usec" 815f76fd327SGerrit Renker " resolution - check your clocksource.\n", __func__, 816f76fd327SGerrit Renker tp.tv_nsec/NSEC_PER_USEC, DCCP_TIME_RESOLUTION); 817f76fd327SGerrit Renker return -ESOCKTNOSUPPORT; 818f76fd327SGerrit Renker } 81934a9e7eaSArnaldo Carvalho de Melo return ccid_register(&ccid3); 8207c657876SArnaldo Carvalho de Melo } 8217c657876SArnaldo Carvalho de Melo module_init(ccid3_module_init); 8227c657876SArnaldo Carvalho de Melo 8237c657876SArnaldo Carvalho de Melo static __exit void ccid3_module_exit(void) 8247c657876SArnaldo Carvalho de Melo { 8257c657876SArnaldo Carvalho de Melo ccid_unregister(&ccid3); 8267c657876SArnaldo Carvalho de Melo } 8277c657876SArnaldo Carvalho de Melo module_exit(ccid3_module_exit); 8287c657876SArnaldo Carvalho de Melo 829e6bccd35SIan McDonald MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>, " 8301f2333aeSArnaldo Carvalho de Melo "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>"); 8317c657876SArnaldo Carvalho de Melo MODULE_DESCRIPTION("DCCP TFRC CCID3 CCID"); 8327c657876SArnaldo Carvalho de Melo MODULE_LICENSE("GPL"); 8337c657876SArnaldo Carvalho de Melo MODULE_ALIAS("net-dccp-ccid-3"); 834