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 [TFRC_SSTATE_TERM] = "TERM", 607c657876SArnaldo Carvalho de Melo }; 617c657876SArnaldo Carvalho de Melo 627c657876SArnaldo Carvalho de Melo return ccid3_state_names[state]; 637c657876SArnaldo Carvalho de Melo } 647c657876SArnaldo Carvalho de Melo #endif 657c657876SArnaldo Carvalho de Melo 66c25a18baSArnaldo Carvalho de Melo static void ccid3_hc_tx_set_state(struct sock *sk, 671f2333aeSArnaldo Carvalho de Melo enum ccid3_hc_tx_states state) 687c657876SArnaldo Carvalho de Melo { 6959725dc2SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 70842d1ef1SGerrit Renker enum ccid3_hc_tx_states oldstate = hctx->state; 717c657876SArnaldo Carvalho de Melo 727c657876SArnaldo Carvalho de Melo ccid3_pr_debug("%s(%p) %-8.8s -> %s\n", 731f2333aeSArnaldo Carvalho de Melo dccp_role(sk), sk, ccid3_tx_state_name(oldstate), 741f2333aeSArnaldo Carvalho de Melo ccid3_tx_state_name(state)); 757c657876SArnaldo Carvalho de Melo WARN_ON(state == oldstate); 76842d1ef1SGerrit Renker hctx->state = state; 777c657876SArnaldo Carvalho de Melo } 787c657876SArnaldo Carvalho de Melo 7917893bc1SGerrit Renker /* 806c08b2cfSGerrit Renker * Compute the initial sending rate X_init in the manner of RFC 3390: 816c08b2cfSGerrit Renker * 826c08b2cfSGerrit Renker * X_init = min(4 * s, max(2 * s, 4380 bytes)) / RTT 836c08b2cfSGerrit Renker * 846c08b2cfSGerrit Renker * Note that RFC 3390 uses MSS, RFC 4342 refers to RFC 3390, and rfc3448bis 856c08b2cfSGerrit Renker * (rev-02) clarifies the use of RFC 3390 with regard to the above formula. 86a21f9f96SGerrit Renker * For consistency with other parts of the code, X_init is scaled by 2^6. 87a21f9f96SGerrit Renker */ 88a21f9f96SGerrit Renker static inline u64 rfc3390_initial_rate(struct sock *sk) 89a21f9f96SGerrit Renker { 906c08b2cfSGerrit Renker const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 91842d1ef1SGerrit Renker const __u32 w_init = clamp_t(__u32, 4380U, 2 * hctx->s, 4 * hctx->s); 92a21f9f96SGerrit Renker 93842d1ef1SGerrit Renker return scaled_div(w_init << 6, hctx->rtt); 94a21f9f96SGerrit Renker } 95a21f9f96SGerrit Renker 96de6f2b59SGerrit Renker /** 97de6f2b59SGerrit Renker * ccid3_update_send_interval - Calculate new t_ipi = s / X_inst 98de6f2b59SGerrit Renker * This respects the granularity of X_inst (64 * bytes/second). 9917893bc1SGerrit Renker */ 100c4e18dadSIlpo Järvinen static void ccid3_update_send_interval(struct ccid3_hc_tx_sock *hctx) 1017c657876SArnaldo Carvalho de Melo { 102842d1ef1SGerrit Renker hctx->t_ipi = scaled_div32(((u64)hctx->s) << 6, hctx->x); 10317893bc1SGerrit Renker 104de6f2b59SGerrit Renker ccid3_pr_debug("t_ipi=%u, s=%u, X=%u\n", hctx->t_ipi, 105de6f2b59SGerrit Renker hctx->s, (unsigned)(hctx->x >> 6)); 1067c657876SArnaldo Carvalho de Melo } 107aa97efd9SGerrit Renker 108a5358fdcSGerrit Renker static u32 ccid3_hc_tx_idle_rtt(struct ccid3_hc_tx_sock *hctx, ktime_t now) 109a5358fdcSGerrit Renker { 110842d1ef1SGerrit Renker u32 delta = ktime_us_delta(now, hctx->t_last_win_count); 111a5358fdcSGerrit Renker 112842d1ef1SGerrit Renker return delta / hctx->rtt; 113a5358fdcSGerrit Renker } 114a5358fdcSGerrit Renker 115aa97efd9SGerrit Renker /** 116aa97efd9SGerrit Renker * ccid3_hc_tx_update_x - Update allowed sending rate X 117aa97efd9SGerrit Renker * @stamp: most recent time if available - can be left NULL. 118aa97efd9SGerrit Renker * This function tracks draft rfc3448bis, check there for latest details. 1195c3fbb6aSGerrit Renker * 1201a21e49aSGerrit Renker * Note: X and X_recv are both stored in units of 64 * bytes/second, to support 1211a21e49aSGerrit Renker * fine-grained resolution of sending rates. This requires scaling by 2^6 1221a21e49aSGerrit Renker * throughout the code. Only X_calc is unscaled (in bytes/second). 1231a21e49aSGerrit Renker * 1247c657876SArnaldo Carvalho de Melo */ 125aa97efd9SGerrit Renker static void ccid3_hc_tx_update_x(struct sock *sk, ktime_t *stamp) 1267c657876SArnaldo Carvalho de Melo { 12759725dc2SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 128842d1ef1SGerrit Renker u64 min_rate = 2 * hctx->x_recv; 129842d1ef1SGerrit Renker const u64 old_x = hctx->x; 130aa97efd9SGerrit Renker ktime_t now = stamp ? *stamp : ktime_get_real(); 1317c657876SArnaldo Carvalho de Melo 1320c150efbSGerrit Renker /* 1330c150efbSGerrit Renker * Handle IDLE periods: do not reduce below RFC3390 initial sending rate 134a5358fdcSGerrit Renker * when idling [RFC 4342, 5.1]. Definition of idling is from rfc3448bis: 135a5358fdcSGerrit Renker * a sender is idle if it has not sent anything over a 2-RTT-period. 1360c150efbSGerrit Renker * For consistency with X and X_recv, min_rate is also scaled by 2^6. 1370c150efbSGerrit Renker */ 138a5358fdcSGerrit Renker if (ccid3_hc_tx_idle_rtt(hctx, now) >= 2) { 1390c150efbSGerrit Renker min_rate = rfc3390_initial_rate(sk); 140842d1ef1SGerrit Renker min_rate = max(min_rate, 2 * hctx->x_recv); 1410c150efbSGerrit Renker } 1420c150efbSGerrit Renker 143842d1ef1SGerrit Renker if (hctx->p > 0) { 1441a21e49aSGerrit Renker 145842d1ef1SGerrit Renker hctx->x = min(((u64)hctx->x_calc) << 6, min_rate); 146842d1ef1SGerrit Renker hctx->x = max(hctx->x, (((u64)hctx->s) << 6) / TFRC_T_MBI); 147b6ee3d4aSArnaldo Carvalho de Melo 148842d1ef1SGerrit Renker } else if (ktime_us_delta(now, hctx->t_ld) - (s64)hctx->rtt >= 0) { 1491a21e49aSGerrit Renker 150842d1ef1SGerrit Renker hctx->x = min(2 * hctx->x, min_rate); 151842d1ef1SGerrit Renker hctx->x = max(hctx->x, 152842d1ef1SGerrit Renker scaled_div(((u64)hctx->s) << 6, hctx->rtt)); 153842d1ef1SGerrit Renker hctx->t_ld = now; 154ac198ea8SArnaldo Carvalho de Melo } 155a79ef76fSGerrit Renker 156842d1ef1SGerrit Renker if (hctx->x != old_x) { 1571761f7d7SGerrit Renker ccid3_pr_debug("X_prev=%u, X_now=%u, X_calc=%u, " 1581761f7d7SGerrit Renker "X_recv=%u\n", (unsigned)(old_x >> 6), 159842d1ef1SGerrit Renker (unsigned)(hctx->x >> 6), hctx->x_calc, 160842d1ef1SGerrit Renker (unsigned)(hctx->x_recv >> 6)); 1618699be7dSIan McDonald 1621266adeeSGerrit Renker ccid3_update_send_interval(hctx); 1637c657876SArnaldo Carvalho de Melo } 1648699be7dSIan McDonald } 1657c657876SArnaldo Carvalho de Melo 16678ad713dSGerrit Renker /* 16778ad713dSGerrit Renker * Track the mean packet size `s' (cf. RFC 4342, 5.3 and RFC 3448, 4.1) 16878ad713dSGerrit Renker * @len: DCCP packet payload size in bytes 16978ad713dSGerrit Renker */ 17078ad713dSGerrit Renker static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hctx, int len) 17178ad713dSGerrit Renker { 172842d1ef1SGerrit Renker const u16 old_s = hctx->s; 1731266adeeSGerrit Renker 174842d1ef1SGerrit Renker hctx->s = tfrc_ewma(hctx->s, len, 9); 1751266adeeSGerrit Renker 176842d1ef1SGerrit Renker if (hctx->s != old_s) 1771266adeeSGerrit Renker ccid3_update_send_interval(hctx); 17878ad713dSGerrit Renker } 17978ad713dSGerrit Renker 1809f8681dbSGerrit Renker /* 1819f8681dbSGerrit Renker * Update Window Counter using the algorithm from [RFC 4342, 8.1]. 182825de27dSGerrit Renker * As elsewhere, RTT > 0 is assumed by using dccp_sample_rtt(). 1839f8681dbSGerrit Renker */ 1849f8681dbSGerrit Renker static inline void ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock *hctx, 1858132da4dSGerrit Renker ktime_t now) 1869f8681dbSGerrit Renker { 187842d1ef1SGerrit Renker u32 delta = ktime_us_delta(now, hctx->t_last_win_count), 188842d1ef1SGerrit Renker quarter_rtts = (4 * delta) / hctx->rtt; 1899f8681dbSGerrit Renker 1909f8681dbSGerrit Renker if (quarter_rtts > 0) { 191842d1ef1SGerrit Renker hctx->t_last_win_count = now; 192842d1ef1SGerrit Renker hctx->last_win_count += min(quarter_rtts, 5U); 193842d1ef1SGerrit Renker hctx->last_win_count &= 0xF; /* mod 16 */ 1949f8681dbSGerrit Renker } 1959f8681dbSGerrit Renker } 1969f8681dbSGerrit Renker 1977c657876SArnaldo Carvalho de Melo static void ccid3_hc_tx_no_feedback_timer(unsigned long data) 1987c657876SArnaldo Carvalho de Melo { 1997c657876SArnaldo Carvalho de Melo struct sock *sk = (struct sock *)data; 20059725dc2SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 2012a1fda6fSGerrit Renker unsigned long t_nfb = USEC_PER_SEC / 5; 2027c657876SArnaldo Carvalho de Melo 2037c657876SArnaldo Carvalho de Melo bh_lock_sock(sk); 2047c657876SArnaldo Carvalho de Melo if (sock_owned_by_user(sk)) { 2057c657876SArnaldo Carvalho de Melo /* Try again later. */ 2067c657876SArnaldo Carvalho de Melo /* XXX: set some sensible MIB */ 20748e03eeeSGerrit Renker goto restart_timer; 2087c657876SArnaldo Carvalho de Melo } 2097c657876SArnaldo Carvalho de Melo 210a9672411SGerrit Renker ccid3_pr_debug("%s(%p, state=%s) - entry \n", dccp_role(sk), sk, 211842d1ef1SGerrit Renker ccid3_tx_state_name(hctx->state)); 2127c657876SArnaldo Carvalho de Melo 213842d1ef1SGerrit Renker if (hctx->state == TFRC_SSTATE_FBACK) 21452515e77SGerrit Renker ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK); 215842d1ef1SGerrit Renker else if (hctx->state != TFRC_SSTATE_NO_FBACK) 21652515e77SGerrit Renker goto out; 21752515e77SGerrit Renker 21852515e77SGerrit Renker /* 21952515e77SGerrit Renker * Determine new allowed sending rate X as per draft rfc3448bis-00, 4.4 220842d1ef1SGerrit Renker * RTO is 0 if and only if no feedback has been received yet. 22152515e77SGerrit Renker */ 222842d1ef1SGerrit Renker if (hctx->t_rto == 0 || hctx->p == 0) { 22352515e77SGerrit Renker 22452515e77SGerrit Renker /* halve send rate directly */ 225842d1ef1SGerrit Renker hctx->x = max(hctx->x / 2, (((u64)hctx->s) << 6) / TFRC_T_MBI); 2261266adeeSGerrit Renker ccid3_update_send_interval(hctx); 22752515e77SGerrit Renker } else { 2281f2333aeSArnaldo Carvalho de Melo /* 22952515e77SGerrit Renker * Modify the cached value of X_recv 230ff586298SGerrit Renker * 23152515e77SGerrit Renker * If (X_calc > 2 * X_recv) 2327c657876SArnaldo Carvalho de Melo * X_recv = max(X_recv / 2, s / (2 * t_mbi)); 2337c657876SArnaldo Carvalho de Melo * Else 2347c657876SArnaldo Carvalho de Melo * X_recv = X_calc / 4; 2351a21e49aSGerrit Renker * 2361a21e49aSGerrit Renker * Note that X_recv is scaled by 2^6 while X_calc is not 2377c657876SArnaldo Carvalho de Melo */ 238842d1ef1SGerrit Renker BUG_ON(hctx->p && !hctx->x_calc); 2397c657876SArnaldo Carvalho de Melo 240842d1ef1SGerrit Renker if (hctx->x_calc > (hctx->x_recv >> 5)) 241842d1ef1SGerrit Renker hctx->x_recv = 242842d1ef1SGerrit Renker max(hctx->x_recv / 2, 243842d1ef1SGerrit Renker (((__u64)hctx->s) << 6) / (2 * TFRC_T_MBI)); 24452515e77SGerrit Renker else { 245842d1ef1SGerrit Renker hctx->x_recv = hctx->x_calc; 246842d1ef1SGerrit Renker hctx->x_recv <<= 4; 2479e8efc82SGerrit Renker } 248aa97efd9SGerrit Renker ccid3_hc_tx_update_x(sk, NULL); 24952515e77SGerrit Renker } 25052515e77SGerrit Renker ccid3_pr_debug("Reduced X to %llu/64 bytes/sec\n", 251842d1ef1SGerrit Renker (unsigned long long)hctx->x); 25252515e77SGerrit Renker 2536b5e633aSArnaldo Carvalho de Melo /* 25452515e77SGerrit Renker * Set new timeout for the nofeedback timer. 2558a508ac2SGerrit Renker * See comments in packet_recv() regarding the value of t_RTO. 2566b5e633aSArnaldo Carvalho de Melo */ 257842d1ef1SGerrit Renker if (unlikely(hctx->t_rto == 0)) /* no feedback received yet */ 25852515e77SGerrit Renker t_nfb = TFRC_INITIAL_TIMEOUT; 25952515e77SGerrit Renker else 260842d1ef1SGerrit Renker t_nfb = max(hctx->t_rto, 2 * hctx->t_ipi); 2617c657876SArnaldo Carvalho de Melo 26248e03eeeSGerrit Renker restart_timer: 263842d1ef1SGerrit Renker sk_reset_timer(sk, &hctx->no_feedback_timer, 2642a1fda6fSGerrit Renker jiffies + usecs_to_jiffies(t_nfb)); 2657c657876SArnaldo Carvalho de Melo out: 2667c657876SArnaldo Carvalho de Melo bh_unlock_sock(sk); 2677c657876SArnaldo Carvalho de Melo sock_put(sk); 2687c657876SArnaldo Carvalho de Melo } 2697c657876SArnaldo Carvalho de Melo 2707da7f456SGerrit Renker /* 2717da7f456SGerrit Renker * returns 2727da7f456SGerrit Renker * > 0: delay (in msecs) that should pass before actually sending 2737da7f456SGerrit Renker * = 0: can send immediately 2747da7f456SGerrit Renker * < 0: error condition; do not send packet 2757da7f456SGerrit Renker */ 2766b57c93dSGerrit Renker static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb) 2777c657876SArnaldo Carvalho de Melo { 2787c657876SArnaldo Carvalho de Melo struct dccp_sock *dp = dccp_sk(sk); 27959725dc2SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 2808132da4dSGerrit Renker ktime_t now = ktime_get_real(); 2818132da4dSGerrit Renker s64 delay; 2827c657876SArnaldo Carvalho de Melo 2837c657876SArnaldo Carvalho de Melo /* 284da335bafSGerrit Renker * This function is called only for Data and DataAck packets. Sending 285da335bafSGerrit Renker * zero-sized Data(Ack)s is theoretically possible, but for congestion 286da335bafSGerrit Renker * control this case is pathological - ignore it. 2877c657876SArnaldo Carvalho de Melo */ 2886b57c93dSGerrit Renker if (unlikely(skb->len == 0)) 289da335bafSGerrit Renker return -EBADMSG; 2907c657876SArnaldo Carvalho de Melo 291842d1ef1SGerrit Renker switch (hctx->state) { 2927c657876SArnaldo Carvalho de Melo case TFRC_SSTATE_NO_SENT: 293842d1ef1SGerrit Renker sk_reset_timer(sk, &hctx->no_feedback_timer, (jiffies + 2948109b02bSArnaldo Carvalho de Melo usecs_to_jiffies(TFRC_INITIAL_TIMEOUT))); 295842d1ef1SGerrit Renker hctx->last_win_count = 0; 296842d1ef1SGerrit Renker hctx->t_last_win_count = now; 29790feeb95SGerrit Renker 29890feeb95SGerrit Renker /* Set t_0 for initial packet */ 299842d1ef1SGerrit Renker hctx->t_nom = now; 30030833ffeSGerrit Renker 301842d1ef1SGerrit Renker hctx->s = skb->len; 30230833ffeSGerrit Renker 30330833ffeSGerrit Renker /* 30430833ffeSGerrit Renker * Use initial RTT sample when available: recommended by erratum 30530833ffeSGerrit Renker * to RFC 4342. This implements the initialisation procedure of 30630833ffeSGerrit Renker * draft rfc3448bis, section 4.2. Remember, X is scaled by 2^6. 30730833ffeSGerrit Renker */ 30830833ffeSGerrit Renker if (dp->dccps_syn_rtt) { 30930833ffeSGerrit Renker ccid3_pr_debug("SYN RTT = %uus\n", dp->dccps_syn_rtt); 310842d1ef1SGerrit Renker hctx->rtt = dp->dccps_syn_rtt; 311842d1ef1SGerrit Renker hctx->x = rfc3390_initial_rate(sk); 312842d1ef1SGerrit Renker hctx->t_ld = now; 31330833ffeSGerrit Renker } else { 3143294f202SGerrit Renker /* 3153294f202SGerrit Renker * Sender does not have RTT sample: 3163294f202SGerrit Renker * - set fallback RTT (RFC 4340, 3.4) since a RTT value 3173294f202SGerrit Renker * is needed in several parts (e.g. window counter); 3183294f202SGerrit Renker * - set sending rate X_pps = 1pps as per RFC 3448, 4.2. 3193294f202SGerrit Renker */ 320842d1ef1SGerrit Renker hctx->rtt = DCCP_FALLBACK_RTT; 321842d1ef1SGerrit Renker hctx->x = hctx->s; 322842d1ef1SGerrit Renker hctx->x <<= 6; 32330833ffeSGerrit Renker } 32430833ffeSGerrit Renker ccid3_update_send_interval(hctx); 32530833ffeSGerrit Renker 32630833ffeSGerrit Renker ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK); 3277c657876SArnaldo Carvalho de Melo break; 3287c657876SArnaldo Carvalho de Melo case TFRC_SSTATE_NO_FBACK: 3297c657876SArnaldo Carvalho de Melo case TFRC_SSTATE_FBACK: 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 break; 34559348b19SGerrit Renker case TFRC_SSTATE_TERM: 346a9672411SGerrit Renker DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk); 3477da7f456SGerrit Renker return -EINVAL; 3487c657876SArnaldo Carvalho de Melo } 3497c657876SArnaldo Carvalho de Melo 3507da7f456SGerrit Renker /* prepare to send now (add options etc.) */ 351507d37cfSArnaldo Carvalho de Melo dp->dccps_hc_tx_insert_options = 1; 352842d1ef1SGerrit Renker DCCP_SKB_CB(skb)->dccpd_ccval = hctx->last_win_count; 353e312d100SGerrit Renker 354e312d100SGerrit Renker /* set the nominal send time for the next following packet */ 355842d1ef1SGerrit Renker hctx->t_nom = ktime_add_us(hctx->t_nom, hctx->t_ipi); 3567da7f456SGerrit Renker return 0; 3577c657876SArnaldo Carvalho de Melo } 3587c657876SArnaldo Carvalho de Melo 3598109b02bSArnaldo Carvalho de Melo static void ccid3_hc_tx_packet_sent(struct sock *sk, int more, 3608109b02bSArnaldo Carvalho de Melo unsigned int len) 3617c657876SArnaldo Carvalho de Melo { 36259725dc2SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 3637c657876SArnaldo Carvalho de Melo 36478ad713dSGerrit Renker ccid3_hc_tx_update_s(hctx, len); 36578ad713dSGerrit Renker 366842d1ef1SGerrit Renker if (tfrc_tx_hist_add(&hctx->hist, dccp_sk(sk)->dccps_gss)) 367c5a1ae9aSGerrit Renker DCCP_CRIT("packet history - out of memory!"); 3687c657876SArnaldo Carvalho de Melo } 3697c657876SArnaldo Carvalho de Melo 3707c657876SArnaldo Carvalho de Melo static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) 3717c657876SArnaldo Carvalho de Melo { 37259725dc2SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 373842d1ef1SGerrit Renker struct ccid3_options_received *opt_recv = &hctx->options_received; 37463b3a73bSGerrit Renker struct tfrc_tx_hist_entry *acked; 3750740d49cSArnaldo Carvalho de Melo ktime_t now; 3762a1fda6fSGerrit Renker unsigned long t_nfb; 3777dfee1a9SGerrit Renker u32 pinv, r_sample; 3781f2333aeSArnaldo Carvalho de Melo 3797c657876SArnaldo Carvalho de Melo /* we are only interested in ACKs */ 3807c657876SArnaldo Carvalho de Melo if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK || 3817c657876SArnaldo Carvalho de Melo DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK)) 3827c657876SArnaldo Carvalho de Melo return; 3835bd370a6SGerrit Renker /* ... and only in the established state */ 384842d1ef1SGerrit Renker if (hctx->state != TFRC_SSTATE_FBACK && 385842d1ef1SGerrit Renker hctx->state != TFRC_SSTATE_NO_FBACK) 3865bd370a6SGerrit Renker return; 3877c657876SArnaldo Carvalho de Melo 38863b3a73bSGerrit Renker /* 38963b3a73bSGerrit Renker * Locate the acknowledged packet in the TX history. 39063b3a73bSGerrit Renker * 39163b3a73bSGerrit Renker * Returning "entry not found" here can for instance happen when 39263b3a73bSGerrit Renker * - the host has not sent out anything (e.g. a passive server), 39363b3a73bSGerrit Renker * - the Ack is outdated (packet with higher Ack number was received), 39463b3a73bSGerrit Renker * - it is a bogus Ack (for a packet not sent on this connection). 39563b3a73bSGerrit Renker */ 39663b3a73bSGerrit Renker acked = tfrc_tx_hist_find_entry(hctx->hist, dccp_hdr_ack_seq(skb)); 39763b3a73bSGerrit Renker if (acked == NULL) 3987c657876SArnaldo Carvalho de Melo return; 39963b3a73bSGerrit Renker /* For the sake of RTT sampling, ignore/remove all older entries */ 40063b3a73bSGerrit Renker tfrc_tx_hist_purge(&acked->next); 40163b3a73bSGerrit Renker 40263b3a73bSGerrit Renker /* Update the moving average for the RTT estimate (RFC 3448, 4.3) */ 40363b3a73bSGerrit Renker now = ktime_get_real(); 40463b3a73bSGerrit Renker r_sample = dccp_sample_rtt(sk, ktime_us_delta(now, acked->stamp)); 40563b3a73bSGerrit Renker hctx->rtt = tfrc_ewma(hctx->rtt, r_sample, 9); 4067c657876SArnaldo Carvalho de Melo 4071a21e49aSGerrit Renker /* Update receive rate in units of 64 * bytes/second */ 408842d1ef1SGerrit Renker hctx->x_recv = opt_recv->ccid3or_receive_rate; 409842d1ef1SGerrit Renker hctx->x_recv <<= 6; 4105c3fbb6aSGerrit Renker 4115bd370a6SGerrit Renker /* Update loss event rate (which is scaled by 1e6) */ 4125c3fbb6aSGerrit Renker pinv = opt_recv->ccid3or_loss_event_rate; 41345393a66SGerrit Renker if (pinv == ~0U || pinv == 0) /* see RFC 4342, 8.5 */ 414842d1ef1SGerrit Renker hctx->p = 0; 41545393a66SGerrit Renker else /* can not exceed 100% */ 416842d1ef1SGerrit Renker hctx->p = scaled_div(1, pinv); 41763b3a73bSGerrit Renker 4181a21e49aSGerrit Renker /* 419d8d1252fSGerrit Renker * Update allowed sending rate X as per draft rfc3448bis-00, 4.2/3 420d8d1252fSGerrit Renker */ 421842d1ef1SGerrit Renker if (hctx->state == TFRC_SSTATE_NO_FBACK) { 422d8d1252fSGerrit Renker ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK); 423d8d1252fSGerrit Renker 424842d1ef1SGerrit Renker if (hctx->t_rto == 0) { 425d8d1252fSGerrit Renker /* 426d8d1252fSGerrit Renker * Initial feedback packet: Larger Initial Windows (4.2) 4271a21e49aSGerrit Renker */ 428842d1ef1SGerrit Renker hctx->x = rfc3390_initial_rate(sk); 429842d1ef1SGerrit Renker hctx->t_ld = now; 430a79ef76fSGerrit Renker 4311266adeeSGerrit Renker ccid3_update_send_interval(hctx); 4325c3fbb6aSGerrit Renker 433d8d1252fSGerrit Renker goto done_computing_x; 434842d1ef1SGerrit Renker } else if (hctx->p == 0) { 435d8d1252fSGerrit Renker /* 436d8d1252fSGerrit Renker * First feedback after nofeedback timer expiry (4.3) 437d8d1252fSGerrit Renker */ 438d8d1252fSGerrit Renker goto done_computing_x; 439d8d1252fSGerrit Renker } 440d8d1252fSGerrit Renker } 4415c3fbb6aSGerrit Renker 442ff586298SGerrit Renker /* Update sending rate (step 4 of [RFC 3448, 4.3]) */ 443842d1ef1SGerrit Renker if (hctx->p > 0) 444842d1ef1SGerrit Renker hctx->x_calc = tfrc_calc_x(hctx->s, hctx->rtt, hctx->p); 445aa97efd9SGerrit Renker ccid3_hc_tx_update_x(sk, &now); 4467c657876SArnaldo Carvalho de Melo 447d8d1252fSGerrit Renker done_computing_x: 4487dfee1a9SGerrit Renker ccid3_pr_debug("%s(%p), RTT=%uus (sample=%uus), s=%u, " 4498109b02bSArnaldo Carvalho de Melo "p=%u, X_calc=%u, X_recv=%u, X=%u\n", 450842d1ef1SGerrit Renker dccp_role(sk), sk, hctx->rtt, r_sample, 451842d1ef1SGerrit Renker hctx->s, hctx->p, hctx->x_calc, 452842d1ef1SGerrit Renker (unsigned)(hctx->x_recv >> 6), 453842d1ef1SGerrit Renker (unsigned)(hctx->x >> 6)); 4547c657876SArnaldo Carvalho de Melo 4557c657876SArnaldo Carvalho de Melo /* unschedule no feedback timer */ 456842d1ef1SGerrit Renker sk_stop_timer(sk, &hctx->no_feedback_timer); 4577c657876SArnaldo Carvalho de Melo 458c530cfb1SArnaldo Carvalho de Melo /* 4598109b02bSArnaldo Carvalho de Melo * As we have calculated new ipi, delta, t_nom it is possible 4608109b02bSArnaldo Carvalho de Melo * that we now can send a packet, so wake up dccp_wait_for_ccid 461c530cfb1SArnaldo Carvalho de Melo */ 462c530cfb1SArnaldo Carvalho de Melo sk->sk_write_space(sk); 4638c60f3faSArnaldo Carvalho de Melo 4648a508ac2SGerrit Renker /* 4658a508ac2SGerrit Renker * Update timeout interval for the nofeedback timer. 4668a508ac2SGerrit Renker * We use a configuration option to increase the lower bound. 4678109b02bSArnaldo Carvalho de Melo * This can help avoid triggering the nofeedback timer too 4688109b02bSArnaldo Carvalho de Melo * often ('spinning') on LANs with small RTTs. 4698a508ac2SGerrit Renker */ 470842d1ef1SGerrit Renker hctx->t_rto = max_t(u32, 4 * hctx->rtt, (CONFIG_IP_DCCP_CCID3_RTO * 4715bd370a6SGerrit Renker (USEC_PER_SEC / 1000))); 4721f2333aeSArnaldo Carvalho de Melo /* 4731f2333aeSArnaldo Carvalho de Melo * Schedule no feedback timer to expire in 4748a508ac2SGerrit Renker * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi) 4751f2333aeSArnaldo Carvalho de Melo */ 476842d1ef1SGerrit Renker t_nfb = max(hctx->t_rto, 2 * hctx->t_ipi); 4777c657876SArnaldo Carvalho de Melo 478a9672411SGerrit Renker ccid3_pr_debug("%s(%p), Scheduled no feedback timer to " 4798109b02bSArnaldo Carvalho de Melo "expire in %lu jiffies (%luus)\n", 480842d1ef1SGerrit Renker dccp_role(sk), sk, usecs_to_jiffies(t_nfb), t_nfb); 4817c657876SArnaldo Carvalho de Melo 482842d1ef1SGerrit Renker sk_reset_timer(sk, &hctx->no_feedback_timer, 4832a1fda6fSGerrit Renker jiffies + usecs_to_jiffies(t_nfb)); 4847c657876SArnaldo Carvalho de Melo } 4857c657876SArnaldo Carvalho de Melo 4863306c781SGerrit Renker static int ccid3_hc_tx_parse_options(struct sock *sk, u8 packet_type, 4873306c781SGerrit Renker u8 option, u8 *optval, u8 optlen) 4887c657876SArnaldo Carvalho de Melo { 48959725dc2SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 490842d1ef1SGerrit Renker struct ccid3_options_received *opt_recv = &hctx->options_received; 49176fd1e87SGerrit Renker __be32 opt_val; 4927c657876SArnaldo Carvalho de Melo 4937c657876SArnaldo Carvalho de Melo switch (option) { 49447a61e7bSGerrit Renker case TFRC_OPT_RECEIVE_RATE: 4957c657876SArnaldo Carvalho de Melo case TFRC_OPT_LOSS_EVENT_RATE: 4963306c781SGerrit Renker /* Must be ignored on Data packets, cf. RFC 4342 8.3 and 8.5 */ 4973306c781SGerrit Renker if (packet_type == DCCP_PKT_DATA) 4983306c781SGerrit Renker break; 4993306c781SGerrit Renker if (unlikely(optlen != 4)) { 50047a61e7bSGerrit Renker DCCP_WARN("%s(%p), invalid len %d for %u\n", 5013306c781SGerrit Renker dccp_role(sk), sk, optlen, option); 50247a61e7bSGerrit Renker return -EINVAL; 5037c657876SArnaldo Carvalho de Melo } 5043306c781SGerrit Renker opt_val = ntohl(get_unaligned((__be32 *)optval)); 5057c657876SArnaldo Carvalho de Melo 50647a61e7bSGerrit Renker if (option == TFRC_OPT_RECEIVE_RATE) { 50747a61e7bSGerrit Renker opt_recv->ccid3or_receive_rate = opt_val; 50847a61e7bSGerrit Renker ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n", 50947a61e7bSGerrit Renker dccp_role(sk), sk, opt_val); 51047a61e7bSGerrit Renker } else { 51147a61e7bSGerrit Renker opt_recv->ccid3or_loss_event_rate = opt_val; 51247a61e7bSGerrit Renker ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n", 51347a61e7bSGerrit Renker dccp_role(sk), sk, opt_val); 51447a61e7bSGerrit Renker } 51547a61e7bSGerrit Renker } 51647a61e7bSGerrit Renker return 0; 5177c657876SArnaldo Carvalho de Melo } 5187c657876SArnaldo Carvalho de Melo 51991f0ebf7SArnaldo Carvalho de Melo static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk) 5207c657876SArnaldo Carvalho de Melo { 52191f0ebf7SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid_priv(ccid); 5227c657876SArnaldo Carvalho de Melo 523842d1ef1SGerrit Renker hctx->state = TFRC_SSTATE_NO_SENT; 524842d1ef1SGerrit Renker hctx->hist = NULL; 525842d1ef1SGerrit Renker setup_timer(&hctx->no_feedback_timer, 526b24b8a24SPavel Emelyanov ccid3_hc_tx_no_feedback_timer, (unsigned long)sk); 5277c657876SArnaldo Carvalho de Melo return 0; 5287c657876SArnaldo Carvalho de Melo } 5297c657876SArnaldo Carvalho de Melo 5307c657876SArnaldo Carvalho de Melo static void ccid3_hc_tx_exit(struct sock *sk) 5317c657876SArnaldo Carvalho de Melo { 53259725dc2SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 5337c657876SArnaldo Carvalho de Melo 5347c657876SArnaldo Carvalho de Melo ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM); 535842d1ef1SGerrit Renker sk_stop_timer(sk, &hctx->no_feedback_timer); 5367c657876SArnaldo Carvalho de Melo 537842d1ef1SGerrit Renker tfrc_tx_hist_purge(&hctx->hist); 5387c657876SArnaldo Carvalho de Melo } 5397c657876SArnaldo Carvalho de Melo 5409bf17475SGerrit Renker static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info) 5419bf17475SGerrit Renker { 542b2e317f4SGerrit Renker info->tcpi_rto = ccid3_hc_tx_sk(sk)->t_rto; 543b2e317f4SGerrit Renker info->tcpi_rtt = ccid3_hc_tx_sk(sk)->rtt; 5449bf17475SGerrit Renker } 5459bf17475SGerrit Renker 5469bf17475SGerrit Renker static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len, 5479bf17475SGerrit Renker u32 __user *optval, int __user *optlen) 5489bf17475SGerrit Renker { 549b2e317f4SGerrit Renker const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 550842d1ef1SGerrit Renker struct tfrc_tx_info tfrc; 5519bf17475SGerrit Renker const void *val; 5529bf17475SGerrit Renker 5539bf17475SGerrit Renker switch (optname) { 5549bf17475SGerrit Renker case DCCP_SOCKOPT_CCID_TX_INFO: 555842d1ef1SGerrit Renker if (len < sizeof(tfrc)) 5569bf17475SGerrit Renker return -EINVAL; 557842d1ef1SGerrit Renker tfrc.tfrctx_x = hctx->x; 558842d1ef1SGerrit Renker tfrc.tfrctx_x_recv = hctx->x_recv; 559842d1ef1SGerrit Renker tfrc.tfrctx_x_calc = hctx->x_calc; 560842d1ef1SGerrit Renker tfrc.tfrctx_rtt = hctx->rtt; 561842d1ef1SGerrit Renker tfrc.tfrctx_p = hctx->p; 562842d1ef1SGerrit Renker tfrc.tfrctx_rto = hctx->t_rto; 563842d1ef1SGerrit Renker tfrc.tfrctx_ipi = hctx->t_ipi; 564842d1ef1SGerrit Renker len = sizeof(tfrc); 565842d1ef1SGerrit Renker val = &tfrc; 5669bf17475SGerrit Renker break; 5679bf17475SGerrit Renker default: 5689bf17475SGerrit Renker return -ENOPROTOOPT; 5699bf17475SGerrit Renker } 5709bf17475SGerrit Renker 5719bf17475SGerrit Renker if (put_user(len, optlen) || copy_to_user(optval, val, len)) 5729bf17475SGerrit Renker return -EFAULT; 5739bf17475SGerrit Renker 5749bf17475SGerrit Renker return 0; 5759bf17475SGerrit Renker } 5769bf17475SGerrit Renker 5779bf17475SGerrit Renker /* 5789bf17475SGerrit Renker * Receiver Half-Connection Routines 5799bf17475SGerrit Renker */ 580b84a2189SArnaldo Carvalho de Melo 581b84a2189SArnaldo Carvalho de Melo /* CCID3 feedback types */ 582b84a2189SArnaldo Carvalho de Melo enum ccid3_fback_type { 583b84a2189SArnaldo Carvalho de Melo CCID3_FBACK_NONE = 0, 584b84a2189SArnaldo Carvalho de Melo CCID3_FBACK_INITIAL, 585b84a2189SArnaldo Carvalho de Melo CCID3_FBACK_PERIODIC, 586b84a2189SArnaldo Carvalho de Melo CCID3_FBACK_PARAM_CHANGE 587b84a2189SArnaldo Carvalho de Melo }; 588b84a2189SArnaldo Carvalho de Melo 58956724aa4SGerrit Renker #ifdef CONFIG_IP_DCCP_CCID3_DEBUG 5907c657876SArnaldo Carvalho de Melo static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state) 5917c657876SArnaldo Carvalho de Melo { 5927c657876SArnaldo Carvalho de Melo static char *ccid3_rx_state_names[] = { 5937c657876SArnaldo Carvalho de Melo [TFRC_RSTATE_NO_DATA] = "NO_DATA", 5947c657876SArnaldo Carvalho de Melo [TFRC_RSTATE_DATA] = "DATA", 5957c657876SArnaldo Carvalho de Melo [TFRC_RSTATE_TERM] = "TERM", 5967c657876SArnaldo Carvalho de Melo }; 5977c657876SArnaldo Carvalho de Melo 5987c657876SArnaldo Carvalho de Melo return ccid3_rx_state_names[state]; 5997c657876SArnaldo Carvalho de Melo } 6007c657876SArnaldo Carvalho de Melo #endif 6017c657876SArnaldo Carvalho de Melo 602c25a18baSArnaldo Carvalho de Melo static void ccid3_hc_rx_set_state(struct sock *sk, 6031f2333aeSArnaldo Carvalho de Melo enum ccid3_hc_rx_states state) 6047c657876SArnaldo Carvalho de Melo { 60559725dc2SArnaldo Carvalho de Melo struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 606842d1ef1SGerrit Renker enum ccid3_hc_rx_states oldstate = hcrx->state; 6077c657876SArnaldo Carvalho de Melo 6087c657876SArnaldo Carvalho de Melo ccid3_pr_debug("%s(%p) %-8.8s -> %s\n", 6091f2333aeSArnaldo Carvalho de Melo dccp_role(sk), sk, ccid3_rx_state_name(oldstate), 6101f2333aeSArnaldo Carvalho de Melo ccid3_rx_state_name(state)); 6117c657876SArnaldo Carvalho de Melo WARN_ON(state == oldstate); 612842d1ef1SGerrit Renker hcrx->state = state; 6137c657876SArnaldo Carvalho de Melo } 6147c657876SArnaldo Carvalho de Melo 615b84a2189SArnaldo Carvalho de Melo static void ccid3_hc_rx_send_feedback(struct sock *sk, 616b84a2189SArnaldo Carvalho de Melo const struct sk_buff *skb, 617b84a2189SArnaldo Carvalho de Melo enum ccid3_fback_type fbtype) 6187c657876SArnaldo Carvalho de Melo { 61959725dc2SArnaldo Carvalho de Melo struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 6207c657876SArnaldo Carvalho de Melo struct dccp_sock *dp = dccp_sk(sk); 621e7c23357SArnaldo Carvalho de Melo ktime_t now; 622b84a2189SArnaldo Carvalho de Melo s64 delta = 0; 6237c657876SArnaldo Carvalho de Melo 624842d1ef1SGerrit Renker if (unlikely(hcrx->state == TFRC_RSTATE_TERM)) 625b84a2189SArnaldo Carvalho de Melo return; 626b84a2189SArnaldo Carvalho de Melo 627e7a81c6dSArnaldo Carvalho de Melo now = ktime_get_real(); 628b6ee3d4aSArnaldo Carvalho de Melo 629b84a2189SArnaldo Carvalho de Melo switch (fbtype) { 630b84a2189SArnaldo Carvalho de Melo case CCID3_FBACK_INITIAL: 631842d1ef1SGerrit Renker hcrx->x_recv = 0; 632842d1ef1SGerrit Renker hcrx->p_inverse = ~0U; /* see RFC 4342, 8.5 */ 6337c657876SArnaldo Carvalho de Melo break; 634b84a2189SArnaldo Carvalho de Melo case CCID3_FBACK_PARAM_CHANGE: 635b84a2189SArnaldo Carvalho de Melo /* 636b84a2189SArnaldo Carvalho de Melo * When parameters change (new loss or p > p_prev), we do not 637b84a2189SArnaldo Carvalho de Melo * have a reliable estimate for R_m of [RFC 3448, 6.2] and so 638b84a2189SArnaldo Carvalho de Melo * need to reuse the previous value of X_recv. However, when 639b84a2189SArnaldo Carvalho de Melo * X_recv was 0 (due to early loss), this would kill X down to 640b84a2189SArnaldo Carvalho de Melo * s/t_mbi (i.e. one packet in 64 seconds). 641b84a2189SArnaldo Carvalho de Melo * To avoid such drastic reduction, we approximate X_recv as 642b84a2189SArnaldo Carvalho de Melo * the number of bytes since last feedback. 643b84a2189SArnaldo Carvalho de Melo * This is a safe fallback, since X is bounded above by X_calc. 644b84a2189SArnaldo Carvalho de Melo */ 645842d1ef1SGerrit Renker if (hcrx->x_recv > 0) 646b84a2189SArnaldo Carvalho de Melo break; 647b84a2189SArnaldo Carvalho de Melo /* fall through */ 648b84a2189SArnaldo Carvalho de Melo case CCID3_FBACK_PERIODIC: 649842d1ef1SGerrit Renker delta = ktime_us_delta(now, hcrx->tstamp_last_feedback); 650b84a2189SArnaldo Carvalho de Melo if (delta <= 0) 651b84a2189SArnaldo Carvalho de Melo DCCP_BUG("delta (%ld) <= 0", (long)delta); 652b84a2189SArnaldo Carvalho de Melo else 653842d1ef1SGerrit Renker hcrx->x_recv = scaled_div32(hcrx->bytes_recv, delta); 6547c657876SArnaldo Carvalho de Melo break; 655b84a2189SArnaldo Carvalho de Melo default: 6567c657876SArnaldo Carvalho de Melo return; 6577c657876SArnaldo Carvalho de Melo } 6587c657876SArnaldo Carvalho de Melo 659842d1ef1SGerrit Renker ccid3_pr_debug("Interval %ldusec, X_recv=%u, 1/p=%u\n", 660842d1ef1SGerrit Renker (long)delta, hcrx->x_recv, hcrx->p_inverse); 6617c657876SArnaldo Carvalho de Melo 662842d1ef1SGerrit Renker hcrx->tstamp_last_feedback = now; 663842d1ef1SGerrit Renker hcrx->last_counter = dccp_hdr(skb)->dccph_ccval; 664842d1ef1SGerrit Renker hcrx->bytes_recv = 0; 6657c657876SArnaldo Carvalho de Melo 666507d37cfSArnaldo Carvalho de Melo dp->dccps_hc_rx_insert_options = 1; 6677c657876SArnaldo Carvalho de Melo dccp_send_ack(sk); 6687c657876SArnaldo Carvalho de Melo } 6697c657876SArnaldo Carvalho de Melo 6702d0817d1SArnaldo Carvalho de Melo static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb) 6717c657876SArnaldo Carvalho de Melo { 672b2e317f4SGerrit Renker const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 67360fe62e7SAndrea Bittau __be32 x_recv, pinv; 6747c657876SArnaldo Carvalho de Melo 67559d203f9SArnaldo Carvalho de Melo if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN)) 6762d0817d1SArnaldo Carvalho de Melo return 0; 6777c657876SArnaldo Carvalho de Melo 6784fded33bSArnaldo Carvalho de Melo if (dccp_packet_without_ack(skb)) 6792d0817d1SArnaldo Carvalho de Melo return 0; 6804fded33bSArnaldo Carvalho de Melo 681842d1ef1SGerrit Renker x_recv = htonl(hcrx->x_recv); 682842d1ef1SGerrit Renker pinv = htonl(hcrx->p_inverse); 6832d0817d1SArnaldo Carvalho de Melo 684385ac2e3SGerrit Renker if (dccp_insert_option(sk, skb, TFRC_OPT_LOSS_EVENT_RATE, 6852d0817d1SArnaldo Carvalho de Melo &pinv, sizeof(pinv)) || 6864fded33bSArnaldo Carvalho de Melo dccp_insert_option(sk, skb, TFRC_OPT_RECEIVE_RATE, 6872d0817d1SArnaldo Carvalho de Melo &x_recv, sizeof(x_recv))) 6882d0817d1SArnaldo Carvalho de Melo return -1; 6892d0817d1SArnaldo Carvalho de Melo 6902d0817d1SArnaldo Carvalho de Melo return 0; 6917c657876SArnaldo Carvalho de Melo } 6927c657876SArnaldo Carvalho de Melo 693954c2db8SGerrit Renker /** ccid3_first_li - Implements [RFC 3448, 6.3.1] 694954c2db8SGerrit Renker * 695954c2db8SGerrit Renker * Determine the length of the first loss interval via inverse lookup. 696954c2db8SGerrit Renker * Assume that X_recv can be computed by the throughput equation 697954c2db8SGerrit Renker * s 698954c2db8SGerrit Renker * X_recv = -------- 699954c2db8SGerrit Renker * R * fval 700954c2db8SGerrit Renker * Find some p such that f(p) = fval; return 1/p (scaled). 701954c2db8SGerrit Renker */ 702954c2db8SGerrit Renker static u32 ccid3_first_li(struct sock *sk) 703954c2db8SGerrit Renker { 704954c2db8SGerrit Renker struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 705954c2db8SGerrit Renker u32 x_recv, p, delta; 706954c2db8SGerrit Renker u64 fval; 707954c2db8SGerrit Renker 708842d1ef1SGerrit Renker if (hcrx->rtt == 0) { 709954c2db8SGerrit Renker DCCP_WARN("No RTT estimate available, using fallback RTT\n"); 710842d1ef1SGerrit Renker hcrx->rtt = DCCP_FALLBACK_RTT; 711954c2db8SGerrit Renker } 712954c2db8SGerrit Renker 713842d1ef1SGerrit Renker delta = ktime_to_us(net_timedelta(hcrx->tstamp_last_feedback)); 714842d1ef1SGerrit Renker x_recv = scaled_div32(hcrx->bytes_recv, delta); 715954c2db8SGerrit Renker if (x_recv == 0) { /* would also trigger divide-by-zero */ 716954c2db8SGerrit Renker DCCP_WARN("X_recv==0\n"); 717842d1ef1SGerrit Renker if (hcrx->x_recv == 0) { 718954c2db8SGerrit Renker DCCP_BUG("stored value of X_recv is zero"); 719954c2db8SGerrit Renker return ~0U; 720954c2db8SGerrit Renker } 721842d1ef1SGerrit Renker x_recv = hcrx->x_recv; 722954c2db8SGerrit Renker } 723954c2db8SGerrit Renker 724842d1ef1SGerrit Renker fval = scaled_div(hcrx->s, hcrx->rtt); 725954c2db8SGerrit Renker fval = scaled_div32(fval, x_recv); 726954c2db8SGerrit Renker p = tfrc_calc_x_reverse_lookup(fval); 727954c2db8SGerrit Renker 728954c2db8SGerrit Renker ccid3_pr_debug("%s(%p), receive rate=%u bytes/s, implied " 729954c2db8SGerrit Renker "loss rate=%u\n", dccp_role(sk), sk, x_recv, p); 730954c2db8SGerrit Renker 731954c2db8SGerrit Renker return p == 0 ? ~0U : scaled_div(1, p); 732954c2db8SGerrit Renker } 733954c2db8SGerrit Renker 7347c657876SArnaldo Carvalho de Melo static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) 7357c657876SArnaldo Carvalho de Melo { 73659725dc2SArnaldo Carvalho de Melo struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 737b84a2189SArnaldo Carvalho de Melo enum ccid3_fback_type do_feedback = CCID3_FBACK_NONE; 7385b5d0e70SGerrit Renker const u64 ndp = dccp_sk(sk)->dccps_options_received.dccpor_ndp; 739b84a2189SArnaldo Carvalho de Melo const bool is_data_packet = dccp_data_packet(skb); 7401f2333aeSArnaldo Carvalho de Melo 741842d1ef1SGerrit Renker if (unlikely(hcrx->state == TFRC_RSTATE_NO_DATA)) { 742b84a2189SArnaldo Carvalho de Melo if (is_data_packet) { 743b84a2189SArnaldo Carvalho de Melo const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4; 744b84a2189SArnaldo Carvalho de Melo do_feedback = CCID3_FBACK_INITIAL; 7457c657876SArnaldo Carvalho de Melo ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA); 746842d1ef1SGerrit Renker hcrx->s = payload; 747b84a2189SArnaldo Carvalho de Melo /* 748842d1ef1SGerrit Renker * Not necessary to update bytes_recv here, 749b84a2189SArnaldo Carvalho de Melo * since X_recv = 0 for the first feedback packet (cf. 750b84a2189SArnaldo Carvalho de Melo * RFC 3448, 6.3) -- gerrit 751b84a2189SArnaldo Carvalho de Melo */ 7527c657876SArnaldo Carvalho de Melo } 753b84a2189SArnaldo Carvalho de Melo goto update_records; 7547c657876SArnaldo Carvalho de Melo } 7557c657876SArnaldo Carvalho de Melo 756842d1ef1SGerrit Renker if (tfrc_rx_hist_duplicate(&hcrx->hist, skb)) 757b84a2189SArnaldo Carvalho de Melo return; /* done receiving */ 7587c657876SArnaldo Carvalho de Melo 759b84a2189SArnaldo Carvalho de Melo if (is_data_packet) { 760b84a2189SArnaldo Carvalho de Melo const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4; 761b84a2189SArnaldo Carvalho de Melo /* 762b84a2189SArnaldo Carvalho de Melo * Update moving-average of s and the sum of received payload bytes 763b84a2189SArnaldo Carvalho de Melo */ 764842d1ef1SGerrit Renker hcrx->s = tfrc_ewma(hcrx->s, payload, 9); 765842d1ef1SGerrit Renker hcrx->bytes_recv += payload; 7667c657876SArnaldo Carvalho de Melo } 767b84a2189SArnaldo Carvalho de Melo 768b84a2189SArnaldo Carvalho de Melo /* 769b552c623SGerrit Renker * Perform loss detection and handle pending losses 770b84a2189SArnaldo Carvalho de Melo */ 771842d1ef1SGerrit Renker if (tfrc_rx_handle_loss(&hcrx->hist, &hcrx->li_hist, 772954c2db8SGerrit Renker skb, ndp, ccid3_first_li, sk)) { 773954c2db8SGerrit Renker do_feedback = CCID3_FBACK_PARAM_CHANGE; 774954c2db8SGerrit Renker goto done_receiving; 775954c2db8SGerrit Renker } 776954c2db8SGerrit Renker 777842d1ef1SGerrit Renker if (tfrc_rx_hist_loss_pending(&hcrx->hist)) 778b552c623SGerrit Renker return; /* done receiving */ 779b84a2189SArnaldo Carvalho de Melo 780b84a2189SArnaldo Carvalho de Melo /* 781b84a2189SArnaldo Carvalho de Melo * Handle data packets: RTT sampling and monitoring p 782b84a2189SArnaldo Carvalho de Melo */ 783b84a2189SArnaldo Carvalho de Melo if (unlikely(!is_data_packet)) 784b84a2189SArnaldo Carvalho de Melo goto update_records; 785b84a2189SArnaldo Carvalho de Melo 786842d1ef1SGerrit Renker if (!tfrc_lh_is_initialised(&hcrx->li_hist)) { 787842d1ef1SGerrit Renker const u32 sample = tfrc_rx_hist_sample_rtt(&hcrx->hist, skb); 788b84a2189SArnaldo Carvalho de Melo /* 789b84a2189SArnaldo Carvalho de Melo * Empty loss history: no loss so far, hence p stays 0. 790b84a2189SArnaldo Carvalho de Melo * Sample RTT values, since an RTT estimate is required for the 791b84a2189SArnaldo Carvalho de Melo * computation of p when the first loss occurs; RFC 3448, 6.3.1. 792b84a2189SArnaldo Carvalho de Melo */ 793b84a2189SArnaldo Carvalho de Melo if (sample != 0) 794842d1ef1SGerrit Renker hcrx->rtt = tfrc_ewma(hcrx->rtt, sample, 9); 795954c2db8SGerrit Renker 796842d1ef1SGerrit Renker } else if (tfrc_lh_update_i_mean(&hcrx->li_hist, skb)) { 797954c2db8SGerrit Renker /* 798954c2db8SGerrit Renker * Step (3) of [RFC 3448, 6.1]: Recompute I_mean and, if I_mean 799954c2db8SGerrit Renker * has decreased (resp. p has increased), send feedback now. 800954c2db8SGerrit Renker */ 801954c2db8SGerrit Renker do_feedback = CCID3_FBACK_PARAM_CHANGE; 802b84a2189SArnaldo Carvalho de Melo } 803b84a2189SArnaldo Carvalho de Melo 804b84a2189SArnaldo Carvalho de Melo /* 805b84a2189SArnaldo Carvalho de Melo * Check if the periodic once-per-RTT feedback is due; RFC 4342, 10.3 806b84a2189SArnaldo Carvalho de Melo */ 807842d1ef1SGerrit Renker if (SUB16(dccp_hdr(skb)->dccph_ccval, hcrx->last_counter) > 3) 808b84a2189SArnaldo Carvalho de Melo do_feedback = CCID3_FBACK_PERIODIC; 809b84a2189SArnaldo Carvalho de Melo 810b84a2189SArnaldo Carvalho de Melo update_records: 811842d1ef1SGerrit Renker tfrc_rx_hist_add_packet(&hcrx->hist, skb, ndp); 812b84a2189SArnaldo Carvalho de Melo 813954c2db8SGerrit Renker done_receiving: 814b84a2189SArnaldo Carvalho de Melo if (do_feedback) 815b84a2189SArnaldo Carvalho de Melo ccid3_hc_rx_send_feedback(sk, skb, do_feedback); 8167c657876SArnaldo Carvalho de Melo } 8177c657876SArnaldo Carvalho de Melo 81891f0ebf7SArnaldo Carvalho de Melo static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk) 8197c657876SArnaldo Carvalho de Melo { 82091f0ebf7SArnaldo Carvalho de Melo struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid); 8217c657876SArnaldo Carvalho de Melo 822842d1ef1SGerrit Renker hcrx->state = TFRC_RSTATE_NO_DATA; 823842d1ef1SGerrit Renker tfrc_lh_init(&hcrx->li_hist); 824842d1ef1SGerrit Renker return tfrc_rx_hist_alloc(&hcrx->hist); 8257c657876SArnaldo Carvalho de Melo } 8267c657876SArnaldo Carvalho de Melo 8277c657876SArnaldo Carvalho de Melo static void ccid3_hc_rx_exit(struct sock *sk) 8287c657876SArnaldo Carvalho de Melo { 82959725dc2SArnaldo Carvalho de Melo struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 8307c657876SArnaldo Carvalho de Melo 8317c657876SArnaldo Carvalho de Melo ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM); 8327c657876SArnaldo Carvalho de Melo 833842d1ef1SGerrit Renker tfrc_rx_hist_purge(&hcrx->hist); 834842d1ef1SGerrit Renker tfrc_lh_cleanup(&hcrx->li_hist); 8357c657876SArnaldo Carvalho de Melo } 8367c657876SArnaldo Carvalho de Melo 8372babe1f6SArnaldo Carvalho de Melo static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info) 8382babe1f6SArnaldo Carvalho de Melo { 839b2e317f4SGerrit Renker info->tcpi_ca_state = ccid3_hc_rx_sk(sk)->state; 8402babe1f6SArnaldo Carvalho de Melo info->tcpi_options |= TCPI_OPT_TIMESTAMPS; 841b2e317f4SGerrit Renker info->tcpi_rcv_rtt = ccid3_hc_rx_sk(sk)->rtt; 8422babe1f6SArnaldo Carvalho de Melo } 8432babe1f6SArnaldo Carvalho de Melo 84488f964dbSArnaldo Carvalho de Melo static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len, 84588f964dbSArnaldo Carvalho de Melo u32 __user *optval, int __user *optlen) 84688f964dbSArnaldo Carvalho de Melo { 847b2e317f4SGerrit Renker const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 8488e138e79SGerrit Renker struct tfrc_rx_info rx_info; 84988f964dbSArnaldo Carvalho de Melo const void *val; 85088f964dbSArnaldo Carvalho de Melo 85188f964dbSArnaldo Carvalho de Melo switch (optname) { 85288f964dbSArnaldo Carvalho de Melo case DCCP_SOCKOPT_CCID_RX_INFO: 8538e138e79SGerrit Renker if (len < sizeof(rx_info)) 85488f964dbSArnaldo Carvalho de Melo return -EINVAL; 855842d1ef1SGerrit Renker rx_info.tfrcrx_x_recv = hcrx->x_recv; 856842d1ef1SGerrit Renker rx_info.tfrcrx_rtt = hcrx->rtt; 857842d1ef1SGerrit Renker rx_info.tfrcrx_p = hcrx->p_inverse == 0 ? ~0U : 858842d1ef1SGerrit Renker scaled_div(1, hcrx->p_inverse); 8598e138e79SGerrit Renker len = sizeof(rx_info); 8608e138e79SGerrit Renker val = &rx_info; 86188f964dbSArnaldo Carvalho de Melo break; 86288f964dbSArnaldo Carvalho de Melo default: 86388f964dbSArnaldo Carvalho de Melo return -ENOPROTOOPT; 86488f964dbSArnaldo Carvalho de Melo } 86588f964dbSArnaldo Carvalho de Melo 86688f964dbSArnaldo Carvalho de Melo if (put_user(len, optlen) || copy_to_user(optval, val, len)) 86788f964dbSArnaldo Carvalho de Melo return -EFAULT; 86888f964dbSArnaldo Carvalho de Melo 86988f964dbSArnaldo Carvalho de Melo return 0; 87088f964dbSArnaldo Carvalho de Melo } 87188f964dbSArnaldo Carvalho de Melo 87291f0ebf7SArnaldo Carvalho de Melo static struct ccid_operations ccid3 = { 8733dd9a7c3SIan McDonald .ccid_id = DCCPC_CCID3, 87484a97b0aSGerrit Renker .ccid_name = "TCP-Friendly Rate Control", 8757c657876SArnaldo Carvalho de Melo .ccid_owner = THIS_MODULE, 87691f0ebf7SArnaldo Carvalho de Melo .ccid_hc_tx_obj_size = sizeof(struct ccid3_hc_tx_sock), 8777c657876SArnaldo Carvalho de Melo .ccid_hc_tx_init = ccid3_hc_tx_init, 8787c657876SArnaldo Carvalho de Melo .ccid_hc_tx_exit = ccid3_hc_tx_exit, 8797c657876SArnaldo Carvalho de Melo .ccid_hc_tx_send_packet = ccid3_hc_tx_send_packet, 8807c657876SArnaldo Carvalho de Melo .ccid_hc_tx_packet_sent = ccid3_hc_tx_packet_sent, 8817c657876SArnaldo Carvalho de Melo .ccid_hc_tx_packet_recv = ccid3_hc_tx_packet_recv, 8827c657876SArnaldo Carvalho de Melo .ccid_hc_tx_parse_options = ccid3_hc_tx_parse_options, 88391f0ebf7SArnaldo Carvalho de Melo .ccid_hc_rx_obj_size = sizeof(struct ccid3_hc_rx_sock), 8847c657876SArnaldo Carvalho de Melo .ccid_hc_rx_init = ccid3_hc_rx_init, 8857c657876SArnaldo Carvalho de Melo .ccid_hc_rx_exit = ccid3_hc_rx_exit, 8867c657876SArnaldo Carvalho de Melo .ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options, 8877c657876SArnaldo Carvalho de Melo .ccid_hc_rx_packet_recv = ccid3_hc_rx_packet_recv, 8882babe1f6SArnaldo Carvalho de Melo .ccid_hc_rx_get_info = ccid3_hc_rx_get_info, 8892babe1f6SArnaldo Carvalho de Melo .ccid_hc_tx_get_info = ccid3_hc_tx_get_info, 89088f964dbSArnaldo Carvalho de Melo .ccid_hc_rx_getsockopt = ccid3_hc_rx_getsockopt, 89188f964dbSArnaldo Carvalho de Melo .ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt, 8927c657876SArnaldo Carvalho de Melo }; 8937c657876SArnaldo Carvalho de Melo 89456724aa4SGerrit Renker #ifdef CONFIG_IP_DCCP_CCID3_DEBUG 89543264991SGerrit Renker module_param(ccid3_debug, bool, 0644); 8967c657876SArnaldo Carvalho de Melo MODULE_PARM_DESC(ccid3_debug, "Enable debug messages"); 89756724aa4SGerrit Renker #endif 8987c657876SArnaldo Carvalho de Melo 8997c657876SArnaldo Carvalho de Melo static __init int ccid3_module_init(void) 9007c657876SArnaldo Carvalho de Melo { 90134a9e7eaSArnaldo Carvalho de Melo return ccid_register(&ccid3); 9027c657876SArnaldo Carvalho de Melo } 9037c657876SArnaldo Carvalho de Melo module_init(ccid3_module_init); 9047c657876SArnaldo Carvalho de Melo 9057c657876SArnaldo Carvalho de Melo static __exit void ccid3_module_exit(void) 9067c657876SArnaldo Carvalho de Melo { 9077c657876SArnaldo Carvalho de Melo ccid_unregister(&ccid3); 9087c657876SArnaldo Carvalho de Melo } 9097c657876SArnaldo Carvalho de Melo module_exit(ccid3_module_exit); 9107c657876SArnaldo Carvalho de Melo 911e6bccd35SIan McDonald MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>, " 9121f2333aeSArnaldo Carvalho de Melo "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>"); 9137c657876SArnaldo Carvalho de Melo MODULE_DESCRIPTION("DCCP TFRC CCID3 CCID"); 9147c657876SArnaldo Carvalho de Melo MODULE_LICENSE("GPL"); 9157c657876SArnaldo Carvalho de Melo MODULE_ALIAS("net-dccp-ccid-3"); 916