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); 37363b3a73bSGerrit Renker struct tfrc_tx_hist_entry *acked; 3740740d49cSArnaldo Carvalho de Melo ktime_t now; 3752a1fda6fSGerrit Renker unsigned long t_nfb; 376ce177ae2SGerrit Renker u32 r_sample; 3771f2333aeSArnaldo Carvalho de Melo 3787c657876SArnaldo Carvalho de Melo /* we are only interested in ACKs */ 3797c657876SArnaldo Carvalho de Melo if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK || 3807c657876SArnaldo Carvalho de Melo DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK)) 3817c657876SArnaldo Carvalho de Melo return; 3825bd370a6SGerrit Renker /* ... and only in the established state */ 383842d1ef1SGerrit Renker if (hctx->state != TFRC_SSTATE_FBACK && 384842d1ef1SGerrit Renker hctx->state != TFRC_SSTATE_NO_FBACK) 3855bd370a6SGerrit Renker return; 3867c657876SArnaldo Carvalho de Melo 38763b3a73bSGerrit Renker /* 38863b3a73bSGerrit Renker * Locate the acknowledged packet in the TX history. 38963b3a73bSGerrit Renker * 39063b3a73bSGerrit Renker * Returning "entry not found" here can for instance happen when 39163b3a73bSGerrit Renker * - the host has not sent out anything (e.g. a passive server), 39263b3a73bSGerrit Renker * - the Ack is outdated (packet with higher Ack number was received), 39363b3a73bSGerrit Renker * - it is a bogus Ack (for a packet not sent on this connection). 39463b3a73bSGerrit Renker */ 39563b3a73bSGerrit Renker acked = tfrc_tx_hist_find_entry(hctx->hist, dccp_hdr_ack_seq(skb)); 39663b3a73bSGerrit Renker if (acked == NULL) 3977c657876SArnaldo Carvalho de Melo return; 39863b3a73bSGerrit Renker /* For the sake of RTT sampling, ignore/remove all older entries */ 39963b3a73bSGerrit Renker tfrc_tx_hist_purge(&acked->next); 40063b3a73bSGerrit Renker 40163b3a73bSGerrit Renker /* Update the moving average for the RTT estimate (RFC 3448, 4.3) */ 40263b3a73bSGerrit Renker now = ktime_get_real(); 40363b3a73bSGerrit Renker r_sample = dccp_sample_rtt(sk, ktime_us_delta(now, acked->stamp)); 40463b3a73bSGerrit Renker hctx->rtt = tfrc_ewma(hctx->rtt, r_sample, 9); 4057c657876SArnaldo Carvalho de Melo 4061a21e49aSGerrit Renker /* 407d8d1252fSGerrit Renker * Update allowed sending rate X as per draft rfc3448bis-00, 4.2/3 408d8d1252fSGerrit Renker */ 409842d1ef1SGerrit Renker if (hctx->state == TFRC_SSTATE_NO_FBACK) { 410d8d1252fSGerrit Renker ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK); 411d8d1252fSGerrit Renker 412842d1ef1SGerrit Renker if (hctx->t_rto == 0) { 413d8d1252fSGerrit Renker /* 414d8d1252fSGerrit Renker * Initial feedback packet: Larger Initial Windows (4.2) 4151a21e49aSGerrit Renker */ 416842d1ef1SGerrit Renker hctx->x = rfc3390_initial_rate(sk); 417842d1ef1SGerrit Renker hctx->t_ld = now; 418a79ef76fSGerrit Renker 4191266adeeSGerrit Renker ccid3_update_send_interval(hctx); 4205c3fbb6aSGerrit Renker 421d8d1252fSGerrit Renker goto done_computing_x; 422842d1ef1SGerrit Renker } else if (hctx->p == 0) { 423d8d1252fSGerrit Renker /* 424d8d1252fSGerrit Renker * First feedback after nofeedback timer expiry (4.3) 425d8d1252fSGerrit Renker */ 426d8d1252fSGerrit Renker goto done_computing_x; 427d8d1252fSGerrit Renker } 428d8d1252fSGerrit Renker } 4295c3fbb6aSGerrit Renker 430ff586298SGerrit Renker /* Update sending rate (step 4 of [RFC 3448, 4.3]) */ 431842d1ef1SGerrit Renker if (hctx->p > 0) 432842d1ef1SGerrit Renker hctx->x_calc = tfrc_calc_x(hctx->s, hctx->rtt, hctx->p); 433aa97efd9SGerrit Renker ccid3_hc_tx_update_x(sk, &now); 4347c657876SArnaldo Carvalho de Melo 435d8d1252fSGerrit Renker done_computing_x: 4367dfee1a9SGerrit Renker ccid3_pr_debug("%s(%p), RTT=%uus (sample=%uus), s=%u, " 4378109b02bSArnaldo Carvalho de Melo "p=%u, X_calc=%u, X_recv=%u, X=%u\n", 438842d1ef1SGerrit Renker dccp_role(sk), sk, hctx->rtt, r_sample, 439842d1ef1SGerrit Renker hctx->s, hctx->p, hctx->x_calc, 440842d1ef1SGerrit Renker (unsigned)(hctx->x_recv >> 6), 441842d1ef1SGerrit Renker (unsigned)(hctx->x >> 6)); 4427c657876SArnaldo Carvalho de Melo 4437c657876SArnaldo Carvalho de Melo /* unschedule no feedback timer */ 444842d1ef1SGerrit Renker sk_stop_timer(sk, &hctx->no_feedback_timer); 4457c657876SArnaldo Carvalho de Melo 446c530cfb1SArnaldo Carvalho de Melo /* 4478109b02bSArnaldo Carvalho de Melo * As we have calculated new ipi, delta, t_nom it is possible 4488109b02bSArnaldo Carvalho de Melo * that we now can send a packet, so wake up dccp_wait_for_ccid 449c530cfb1SArnaldo Carvalho de Melo */ 450c530cfb1SArnaldo Carvalho de Melo sk->sk_write_space(sk); 4518c60f3faSArnaldo Carvalho de Melo 4528a508ac2SGerrit Renker /* 4538a508ac2SGerrit Renker * Update timeout interval for the nofeedback timer. 4548a508ac2SGerrit Renker * We use a configuration option to increase the lower bound. 4558109b02bSArnaldo Carvalho de Melo * This can help avoid triggering the nofeedback timer too 4568109b02bSArnaldo Carvalho de Melo * often ('spinning') on LANs with small RTTs. 4578a508ac2SGerrit Renker */ 458842d1ef1SGerrit Renker hctx->t_rto = max_t(u32, 4 * hctx->rtt, (CONFIG_IP_DCCP_CCID3_RTO * 4595bd370a6SGerrit Renker (USEC_PER_SEC / 1000))); 4601f2333aeSArnaldo Carvalho de Melo /* 4611f2333aeSArnaldo Carvalho de Melo * Schedule no feedback timer to expire in 4628a508ac2SGerrit Renker * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi) 4631f2333aeSArnaldo Carvalho de Melo */ 464842d1ef1SGerrit Renker t_nfb = max(hctx->t_rto, 2 * hctx->t_ipi); 4657c657876SArnaldo Carvalho de Melo 466a9672411SGerrit Renker ccid3_pr_debug("%s(%p), Scheduled no feedback timer to " 4678109b02bSArnaldo Carvalho de Melo "expire in %lu jiffies (%luus)\n", 468842d1ef1SGerrit Renker dccp_role(sk), sk, usecs_to_jiffies(t_nfb), t_nfb); 4697c657876SArnaldo Carvalho de Melo 470842d1ef1SGerrit Renker sk_reset_timer(sk, &hctx->no_feedback_timer, 4712a1fda6fSGerrit Renker jiffies + usecs_to_jiffies(t_nfb)); 4727c657876SArnaldo Carvalho de Melo } 4737c657876SArnaldo Carvalho de Melo 4743306c781SGerrit Renker static int ccid3_hc_tx_parse_options(struct sock *sk, u8 packet_type, 4753306c781SGerrit Renker u8 option, u8 *optval, u8 optlen) 4767c657876SArnaldo Carvalho de Melo { 47759725dc2SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 47876fd1e87SGerrit Renker __be32 opt_val; 4797c657876SArnaldo Carvalho de Melo 4807c657876SArnaldo Carvalho de Melo switch (option) { 48147a61e7bSGerrit Renker case TFRC_OPT_RECEIVE_RATE: 4827c657876SArnaldo Carvalho de Melo case TFRC_OPT_LOSS_EVENT_RATE: 4833306c781SGerrit Renker /* Must be ignored on Data packets, cf. RFC 4342 8.3 and 8.5 */ 4843306c781SGerrit Renker if (packet_type == DCCP_PKT_DATA) 4853306c781SGerrit Renker break; 4863306c781SGerrit Renker if (unlikely(optlen != 4)) { 48747a61e7bSGerrit Renker DCCP_WARN("%s(%p), invalid len %d for %u\n", 4883306c781SGerrit Renker dccp_role(sk), sk, optlen, option); 48947a61e7bSGerrit Renker return -EINVAL; 4907c657876SArnaldo Carvalho de Melo } 4913306c781SGerrit Renker opt_val = ntohl(get_unaligned((__be32 *)optval)); 4927c657876SArnaldo Carvalho de Melo 49347a61e7bSGerrit Renker if (option == TFRC_OPT_RECEIVE_RATE) { 494ce177ae2SGerrit Renker /* Receive Rate is kept in units of 64 bytes/second */ 495ce177ae2SGerrit Renker hctx->x_recv = opt_val; 496ce177ae2SGerrit Renker hctx->x_recv <<= 6; 497ce177ae2SGerrit Renker 49847a61e7bSGerrit Renker ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n", 49947a61e7bSGerrit Renker dccp_role(sk), sk, opt_val); 50047a61e7bSGerrit Renker } else { 501ce177ae2SGerrit Renker /* Update the fixpoint Loss Event Rate fraction */ 502ce177ae2SGerrit Renker hctx->p = tfrc_invert_loss_event_rate(opt_val); 503ce177ae2SGerrit Renker 50447a61e7bSGerrit Renker ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n", 50547a61e7bSGerrit Renker dccp_role(sk), sk, opt_val); 50647a61e7bSGerrit Renker } 50747a61e7bSGerrit Renker } 50847a61e7bSGerrit Renker return 0; 5097c657876SArnaldo Carvalho de Melo } 5107c657876SArnaldo Carvalho de Melo 51191f0ebf7SArnaldo Carvalho de Melo static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk) 5127c657876SArnaldo Carvalho de Melo { 51391f0ebf7SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid_priv(ccid); 5147c657876SArnaldo Carvalho de Melo 515842d1ef1SGerrit Renker hctx->state = TFRC_SSTATE_NO_SENT; 516842d1ef1SGerrit Renker hctx->hist = NULL; 517842d1ef1SGerrit Renker setup_timer(&hctx->no_feedback_timer, 518b24b8a24SPavel Emelyanov ccid3_hc_tx_no_feedback_timer, (unsigned long)sk); 5197c657876SArnaldo Carvalho de Melo return 0; 5207c657876SArnaldo Carvalho de Melo } 5217c657876SArnaldo Carvalho de Melo 5227c657876SArnaldo Carvalho de Melo static void ccid3_hc_tx_exit(struct sock *sk) 5237c657876SArnaldo Carvalho de Melo { 52459725dc2SArnaldo Carvalho de Melo struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 5257c657876SArnaldo Carvalho de Melo 5267c657876SArnaldo Carvalho de Melo ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM); 527842d1ef1SGerrit Renker sk_stop_timer(sk, &hctx->no_feedback_timer); 5287c657876SArnaldo Carvalho de Melo 529842d1ef1SGerrit Renker tfrc_tx_hist_purge(&hctx->hist); 5307c657876SArnaldo Carvalho de Melo } 5317c657876SArnaldo Carvalho de Melo 5329bf17475SGerrit Renker static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info) 5339bf17475SGerrit Renker { 534b2e317f4SGerrit Renker info->tcpi_rto = ccid3_hc_tx_sk(sk)->t_rto; 535b2e317f4SGerrit Renker info->tcpi_rtt = ccid3_hc_tx_sk(sk)->rtt; 5369bf17475SGerrit Renker } 5379bf17475SGerrit Renker 5389bf17475SGerrit Renker static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len, 5399bf17475SGerrit Renker u32 __user *optval, int __user *optlen) 5409bf17475SGerrit Renker { 541b2e317f4SGerrit Renker const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk); 542842d1ef1SGerrit Renker struct tfrc_tx_info tfrc; 5439bf17475SGerrit Renker const void *val; 5449bf17475SGerrit Renker 5459bf17475SGerrit Renker switch (optname) { 5469bf17475SGerrit Renker case DCCP_SOCKOPT_CCID_TX_INFO: 547842d1ef1SGerrit Renker if (len < sizeof(tfrc)) 5489bf17475SGerrit Renker return -EINVAL; 549842d1ef1SGerrit Renker tfrc.tfrctx_x = hctx->x; 550842d1ef1SGerrit Renker tfrc.tfrctx_x_recv = hctx->x_recv; 551842d1ef1SGerrit Renker tfrc.tfrctx_x_calc = hctx->x_calc; 552842d1ef1SGerrit Renker tfrc.tfrctx_rtt = hctx->rtt; 553842d1ef1SGerrit Renker tfrc.tfrctx_p = hctx->p; 554842d1ef1SGerrit Renker tfrc.tfrctx_rto = hctx->t_rto; 555842d1ef1SGerrit Renker tfrc.tfrctx_ipi = hctx->t_ipi; 556842d1ef1SGerrit Renker len = sizeof(tfrc); 557842d1ef1SGerrit Renker val = &tfrc; 5589bf17475SGerrit Renker break; 5599bf17475SGerrit Renker default: 5609bf17475SGerrit Renker return -ENOPROTOOPT; 5619bf17475SGerrit Renker } 5629bf17475SGerrit Renker 5639bf17475SGerrit Renker if (put_user(len, optlen) || copy_to_user(optval, val, len)) 5649bf17475SGerrit Renker return -EFAULT; 5659bf17475SGerrit Renker 5669bf17475SGerrit Renker return 0; 5679bf17475SGerrit Renker } 5689bf17475SGerrit Renker 5699bf17475SGerrit Renker /* 5709bf17475SGerrit Renker * Receiver Half-Connection Routines 5719bf17475SGerrit Renker */ 572b84a2189SArnaldo Carvalho de Melo 573b84a2189SArnaldo Carvalho de Melo /* CCID3 feedback types */ 574b84a2189SArnaldo Carvalho de Melo enum ccid3_fback_type { 575b84a2189SArnaldo Carvalho de Melo CCID3_FBACK_NONE = 0, 576b84a2189SArnaldo Carvalho de Melo CCID3_FBACK_INITIAL, 577b84a2189SArnaldo Carvalho de Melo CCID3_FBACK_PERIODIC, 578b84a2189SArnaldo Carvalho de Melo CCID3_FBACK_PARAM_CHANGE 579b84a2189SArnaldo Carvalho de Melo }; 580b84a2189SArnaldo Carvalho de Melo 58156724aa4SGerrit Renker #ifdef CONFIG_IP_DCCP_CCID3_DEBUG 5827c657876SArnaldo Carvalho de Melo static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state) 5837c657876SArnaldo Carvalho de Melo { 5847c657876SArnaldo Carvalho de Melo static char *ccid3_rx_state_names[] = { 5857c657876SArnaldo Carvalho de Melo [TFRC_RSTATE_NO_DATA] = "NO_DATA", 5867c657876SArnaldo Carvalho de Melo [TFRC_RSTATE_DATA] = "DATA", 5877c657876SArnaldo Carvalho de Melo [TFRC_RSTATE_TERM] = "TERM", 5887c657876SArnaldo Carvalho de Melo }; 5897c657876SArnaldo Carvalho de Melo 5907c657876SArnaldo Carvalho de Melo return ccid3_rx_state_names[state]; 5917c657876SArnaldo Carvalho de Melo } 5927c657876SArnaldo Carvalho de Melo #endif 5937c657876SArnaldo Carvalho de Melo 594c25a18baSArnaldo Carvalho de Melo static void ccid3_hc_rx_set_state(struct sock *sk, 5951f2333aeSArnaldo Carvalho de Melo enum ccid3_hc_rx_states state) 5967c657876SArnaldo Carvalho de Melo { 59759725dc2SArnaldo Carvalho de Melo struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 598842d1ef1SGerrit Renker enum ccid3_hc_rx_states oldstate = hcrx->state; 5997c657876SArnaldo Carvalho de Melo 6007c657876SArnaldo Carvalho de Melo ccid3_pr_debug("%s(%p) %-8.8s -> %s\n", 6011f2333aeSArnaldo Carvalho de Melo dccp_role(sk), sk, ccid3_rx_state_name(oldstate), 6021f2333aeSArnaldo Carvalho de Melo ccid3_rx_state_name(state)); 6037c657876SArnaldo Carvalho de Melo WARN_ON(state == oldstate); 604842d1ef1SGerrit Renker hcrx->state = state; 6057c657876SArnaldo Carvalho de Melo } 6067c657876SArnaldo Carvalho de Melo 607b84a2189SArnaldo Carvalho de Melo static void ccid3_hc_rx_send_feedback(struct sock *sk, 608b84a2189SArnaldo Carvalho de Melo const struct sk_buff *skb, 609b84a2189SArnaldo Carvalho de Melo enum ccid3_fback_type fbtype) 6107c657876SArnaldo Carvalho de Melo { 61159725dc2SArnaldo Carvalho de Melo struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 6127c657876SArnaldo Carvalho de Melo struct dccp_sock *dp = dccp_sk(sk); 613e7c23357SArnaldo Carvalho de Melo ktime_t now; 614b84a2189SArnaldo Carvalho de Melo s64 delta = 0; 6157c657876SArnaldo Carvalho de Melo 616842d1ef1SGerrit Renker if (unlikely(hcrx->state == TFRC_RSTATE_TERM)) 617b84a2189SArnaldo Carvalho de Melo return; 618b84a2189SArnaldo Carvalho de Melo 619e7a81c6dSArnaldo Carvalho de Melo now = ktime_get_real(); 620b6ee3d4aSArnaldo Carvalho de Melo 621b84a2189SArnaldo Carvalho de Melo switch (fbtype) { 622b84a2189SArnaldo Carvalho de Melo case CCID3_FBACK_INITIAL: 623842d1ef1SGerrit Renker hcrx->x_recv = 0; 624842d1ef1SGerrit Renker hcrx->p_inverse = ~0U; /* see RFC 4342, 8.5 */ 6257c657876SArnaldo Carvalho de Melo break; 626b84a2189SArnaldo Carvalho de Melo case CCID3_FBACK_PARAM_CHANGE: 627b84a2189SArnaldo Carvalho de Melo /* 628b84a2189SArnaldo Carvalho de Melo * When parameters change (new loss or p > p_prev), we do not 629b84a2189SArnaldo Carvalho de Melo * have a reliable estimate for R_m of [RFC 3448, 6.2] and so 630b84a2189SArnaldo Carvalho de Melo * need to reuse the previous value of X_recv. However, when 631b84a2189SArnaldo Carvalho de Melo * X_recv was 0 (due to early loss), this would kill X down to 632b84a2189SArnaldo Carvalho de Melo * s/t_mbi (i.e. one packet in 64 seconds). 633b84a2189SArnaldo Carvalho de Melo * To avoid such drastic reduction, we approximate X_recv as 634b84a2189SArnaldo Carvalho de Melo * the number of bytes since last feedback. 635b84a2189SArnaldo Carvalho de Melo * This is a safe fallback, since X is bounded above by X_calc. 636b84a2189SArnaldo Carvalho de Melo */ 637842d1ef1SGerrit Renker if (hcrx->x_recv > 0) 638b84a2189SArnaldo Carvalho de Melo break; 639b84a2189SArnaldo Carvalho de Melo /* fall through */ 640b84a2189SArnaldo Carvalho de Melo case CCID3_FBACK_PERIODIC: 641842d1ef1SGerrit Renker delta = ktime_us_delta(now, hcrx->tstamp_last_feedback); 642b84a2189SArnaldo Carvalho de Melo if (delta <= 0) 643b84a2189SArnaldo Carvalho de Melo DCCP_BUG("delta (%ld) <= 0", (long)delta); 644b84a2189SArnaldo Carvalho de Melo else 645842d1ef1SGerrit Renker hcrx->x_recv = scaled_div32(hcrx->bytes_recv, delta); 6467c657876SArnaldo Carvalho de Melo break; 647b84a2189SArnaldo Carvalho de Melo default: 6487c657876SArnaldo Carvalho de Melo return; 6497c657876SArnaldo Carvalho de Melo } 6507c657876SArnaldo Carvalho de Melo 651842d1ef1SGerrit Renker ccid3_pr_debug("Interval %ldusec, X_recv=%u, 1/p=%u\n", 652842d1ef1SGerrit Renker (long)delta, hcrx->x_recv, hcrx->p_inverse); 6537c657876SArnaldo Carvalho de Melo 654842d1ef1SGerrit Renker hcrx->tstamp_last_feedback = now; 655842d1ef1SGerrit Renker hcrx->last_counter = dccp_hdr(skb)->dccph_ccval; 656842d1ef1SGerrit Renker hcrx->bytes_recv = 0; 6577c657876SArnaldo Carvalho de Melo 658507d37cfSArnaldo Carvalho de Melo dp->dccps_hc_rx_insert_options = 1; 6597c657876SArnaldo Carvalho de Melo dccp_send_ack(sk); 6607c657876SArnaldo Carvalho de Melo } 6617c657876SArnaldo Carvalho de Melo 6622d0817d1SArnaldo Carvalho de Melo static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb) 6637c657876SArnaldo Carvalho de Melo { 664b2e317f4SGerrit Renker const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 66560fe62e7SAndrea Bittau __be32 x_recv, pinv; 6667c657876SArnaldo Carvalho de Melo 66759d203f9SArnaldo Carvalho de Melo if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN)) 6682d0817d1SArnaldo Carvalho de Melo return 0; 6697c657876SArnaldo Carvalho de Melo 6704fded33bSArnaldo Carvalho de Melo if (dccp_packet_without_ack(skb)) 6712d0817d1SArnaldo Carvalho de Melo return 0; 6724fded33bSArnaldo Carvalho de Melo 673842d1ef1SGerrit Renker x_recv = htonl(hcrx->x_recv); 674842d1ef1SGerrit Renker pinv = htonl(hcrx->p_inverse); 6752d0817d1SArnaldo Carvalho de Melo 676385ac2e3SGerrit Renker if (dccp_insert_option(sk, skb, TFRC_OPT_LOSS_EVENT_RATE, 6772d0817d1SArnaldo Carvalho de Melo &pinv, sizeof(pinv)) || 6784fded33bSArnaldo Carvalho de Melo dccp_insert_option(sk, skb, TFRC_OPT_RECEIVE_RATE, 6792d0817d1SArnaldo Carvalho de Melo &x_recv, sizeof(x_recv))) 6802d0817d1SArnaldo Carvalho de Melo return -1; 6812d0817d1SArnaldo Carvalho de Melo 6822d0817d1SArnaldo Carvalho de Melo return 0; 6837c657876SArnaldo Carvalho de Melo } 6847c657876SArnaldo Carvalho de Melo 685954c2db8SGerrit Renker /** ccid3_first_li - Implements [RFC 3448, 6.3.1] 686954c2db8SGerrit Renker * 687954c2db8SGerrit Renker * Determine the length of the first loss interval via inverse lookup. 688954c2db8SGerrit Renker * Assume that X_recv can be computed by the throughput equation 689954c2db8SGerrit Renker * s 690954c2db8SGerrit Renker * X_recv = -------- 691954c2db8SGerrit Renker * R * fval 692954c2db8SGerrit Renker * Find some p such that f(p) = fval; return 1/p (scaled). 693954c2db8SGerrit Renker */ 694954c2db8SGerrit Renker static u32 ccid3_first_li(struct sock *sk) 695954c2db8SGerrit Renker { 696954c2db8SGerrit Renker struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 697954c2db8SGerrit Renker u32 x_recv, p, delta; 698954c2db8SGerrit Renker u64 fval; 699954c2db8SGerrit Renker 700842d1ef1SGerrit Renker if (hcrx->rtt == 0) { 701954c2db8SGerrit Renker DCCP_WARN("No RTT estimate available, using fallback RTT\n"); 702842d1ef1SGerrit Renker hcrx->rtt = DCCP_FALLBACK_RTT; 703954c2db8SGerrit Renker } 704954c2db8SGerrit Renker 705842d1ef1SGerrit Renker delta = ktime_to_us(net_timedelta(hcrx->tstamp_last_feedback)); 706842d1ef1SGerrit Renker x_recv = scaled_div32(hcrx->bytes_recv, delta); 707954c2db8SGerrit Renker if (x_recv == 0) { /* would also trigger divide-by-zero */ 708954c2db8SGerrit Renker DCCP_WARN("X_recv==0\n"); 709842d1ef1SGerrit Renker if (hcrx->x_recv == 0) { 710954c2db8SGerrit Renker DCCP_BUG("stored value of X_recv is zero"); 711954c2db8SGerrit Renker return ~0U; 712954c2db8SGerrit Renker } 713842d1ef1SGerrit Renker x_recv = hcrx->x_recv; 714954c2db8SGerrit Renker } 715954c2db8SGerrit Renker 716842d1ef1SGerrit Renker fval = scaled_div(hcrx->s, hcrx->rtt); 717954c2db8SGerrit Renker fval = scaled_div32(fval, x_recv); 718954c2db8SGerrit Renker p = tfrc_calc_x_reverse_lookup(fval); 719954c2db8SGerrit Renker 720954c2db8SGerrit Renker ccid3_pr_debug("%s(%p), receive rate=%u bytes/s, implied " 721954c2db8SGerrit Renker "loss rate=%u\n", dccp_role(sk), sk, x_recv, p); 722954c2db8SGerrit Renker 723954c2db8SGerrit Renker return p == 0 ? ~0U : scaled_div(1, p); 724954c2db8SGerrit Renker } 725954c2db8SGerrit Renker 7267c657876SArnaldo Carvalho de Melo static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) 7277c657876SArnaldo Carvalho de Melo { 72859725dc2SArnaldo Carvalho de Melo struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 729b84a2189SArnaldo Carvalho de Melo enum ccid3_fback_type do_feedback = CCID3_FBACK_NONE; 7305b5d0e70SGerrit Renker const u64 ndp = dccp_sk(sk)->dccps_options_received.dccpor_ndp; 731b84a2189SArnaldo Carvalho de Melo const bool is_data_packet = dccp_data_packet(skb); 7321f2333aeSArnaldo Carvalho de Melo 733842d1ef1SGerrit Renker if (unlikely(hcrx->state == TFRC_RSTATE_NO_DATA)) { 734b84a2189SArnaldo Carvalho de Melo if (is_data_packet) { 735b84a2189SArnaldo Carvalho de Melo const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4; 736b84a2189SArnaldo Carvalho de Melo do_feedback = CCID3_FBACK_INITIAL; 7377c657876SArnaldo Carvalho de Melo ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA); 738842d1ef1SGerrit Renker hcrx->s = payload; 739b84a2189SArnaldo Carvalho de Melo /* 740842d1ef1SGerrit Renker * Not necessary to update bytes_recv here, 741b84a2189SArnaldo Carvalho de Melo * since X_recv = 0 for the first feedback packet (cf. 742b84a2189SArnaldo Carvalho de Melo * RFC 3448, 6.3) -- gerrit 743b84a2189SArnaldo Carvalho de Melo */ 7447c657876SArnaldo Carvalho de Melo } 745b84a2189SArnaldo Carvalho de Melo goto update_records; 7467c657876SArnaldo Carvalho de Melo } 7477c657876SArnaldo Carvalho de Melo 748842d1ef1SGerrit Renker if (tfrc_rx_hist_duplicate(&hcrx->hist, skb)) 749b84a2189SArnaldo Carvalho de Melo return; /* done receiving */ 7507c657876SArnaldo Carvalho de Melo 751b84a2189SArnaldo Carvalho de Melo if (is_data_packet) { 752b84a2189SArnaldo Carvalho de Melo const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4; 753b84a2189SArnaldo Carvalho de Melo /* 754b84a2189SArnaldo Carvalho de Melo * Update moving-average of s and the sum of received payload bytes 755b84a2189SArnaldo Carvalho de Melo */ 756842d1ef1SGerrit Renker hcrx->s = tfrc_ewma(hcrx->s, payload, 9); 757842d1ef1SGerrit Renker hcrx->bytes_recv += payload; 7587c657876SArnaldo Carvalho de Melo } 759b84a2189SArnaldo Carvalho de Melo 760b84a2189SArnaldo Carvalho de Melo /* 761b552c623SGerrit Renker * Perform loss detection and handle pending losses 762b84a2189SArnaldo Carvalho de Melo */ 763842d1ef1SGerrit Renker if (tfrc_rx_handle_loss(&hcrx->hist, &hcrx->li_hist, 764954c2db8SGerrit Renker skb, ndp, ccid3_first_li, sk)) { 765954c2db8SGerrit Renker do_feedback = CCID3_FBACK_PARAM_CHANGE; 766954c2db8SGerrit Renker goto done_receiving; 767954c2db8SGerrit Renker } 768954c2db8SGerrit Renker 769842d1ef1SGerrit Renker if (tfrc_rx_hist_loss_pending(&hcrx->hist)) 770b552c623SGerrit Renker return; /* done receiving */ 771b84a2189SArnaldo Carvalho de Melo 772b84a2189SArnaldo Carvalho de Melo /* 773b84a2189SArnaldo Carvalho de Melo * Handle data packets: RTT sampling and monitoring p 774b84a2189SArnaldo Carvalho de Melo */ 775b84a2189SArnaldo Carvalho de Melo if (unlikely(!is_data_packet)) 776b84a2189SArnaldo Carvalho de Melo goto update_records; 777b84a2189SArnaldo Carvalho de Melo 778842d1ef1SGerrit Renker if (!tfrc_lh_is_initialised(&hcrx->li_hist)) { 779842d1ef1SGerrit Renker const u32 sample = tfrc_rx_hist_sample_rtt(&hcrx->hist, skb); 780b84a2189SArnaldo Carvalho de Melo /* 781b84a2189SArnaldo Carvalho de Melo * Empty loss history: no loss so far, hence p stays 0. 782b84a2189SArnaldo Carvalho de Melo * Sample RTT values, since an RTT estimate is required for the 783b84a2189SArnaldo Carvalho de Melo * computation of p when the first loss occurs; RFC 3448, 6.3.1. 784b84a2189SArnaldo Carvalho de Melo */ 785b84a2189SArnaldo Carvalho de Melo if (sample != 0) 786842d1ef1SGerrit Renker hcrx->rtt = tfrc_ewma(hcrx->rtt, sample, 9); 787954c2db8SGerrit Renker 788842d1ef1SGerrit Renker } else if (tfrc_lh_update_i_mean(&hcrx->li_hist, skb)) { 789954c2db8SGerrit Renker /* 790954c2db8SGerrit Renker * Step (3) of [RFC 3448, 6.1]: Recompute I_mean and, if I_mean 791954c2db8SGerrit Renker * has decreased (resp. p has increased), send feedback now. 792954c2db8SGerrit Renker */ 793954c2db8SGerrit Renker do_feedback = CCID3_FBACK_PARAM_CHANGE; 794b84a2189SArnaldo Carvalho de Melo } 795b84a2189SArnaldo Carvalho de Melo 796b84a2189SArnaldo Carvalho de Melo /* 797b84a2189SArnaldo Carvalho de Melo * Check if the periodic once-per-RTT feedback is due; RFC 4342, 10.3 798b84a2189SArnaldo Carvalho de Melo */ 799842d1ef1SGerrit Renker if (SUB16(dccp_hdr(skb)->dccph_ccval, hcrx->last_counter) > 3) 800b84a2189SArnaldo Carvalho de Melo do_feedback = CCID3_FBACK_PERIODIC; 801b84a2189SArnaldo Carvalho de Melo 802b84a2189SArnaldo Carvalho de Melo update_records: 803842d1ef1SGerrit Renker tfrc_rx_hist_add_packet(&hcrx->hist, skb, ndp); 804b84a2189SArnaldo Carvalho de Melo 805954c2db8SGerrit Renker done_receiving: 806b84a2189SArnaldo Carvalho de Melo if (do_feedback) 807b84a2189SArnaldo Carvalho de Melo ccid3_hc_rx_send_feedback(sk, skb, do_feedback); 8087c657876SArnaldo Carvalho de Melo } 8097c657876SArnaldo Carvalho de Melo 81091f0ebf7SArnaldo Carvalho de Melo static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk) 8117c657876SArnaldo Carvalho de Melo { 81291f0ebf7SArnaldo Carvalho de Melo struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid); 8137c657876SArnaldo Carvalho de Melo 814842d1ef1SGerrit Renker hcrx->state = TFRC_RSTATE_NO_DATA; 815842d1ef1SGerrit Renker tfrc_lh_init(&hcrx->li_hist); 816842d1ef1SGerrit Renker return tfrc_rx_hist_alloc(&hcrx->hist); 8177c657876SArnaldo Carvalho de Melo } 8187c657876SArnaldo Carvalho de Melo 8197c657876SArnaldo Carvalho de Melo static void ccid3_hc_rx_exit(struct sock *sk) 8207c657876SArnaldo Carvalho de Melo { 82159725dc2SArnaldo Carvalho de Melo struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 8227c657876SArnaldo Carvalho de Melo 8237c657876SArnaldo Carvalho de Melo ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM); 8247c657876SArnaldo Carvalho de Melo 825842d1ef1SGerrit Renker tfrc_rx_hist_purge(&hcrx->hist); 826842d1ef1SGerrit Renker tfrc_lh_cleanup(&hcrx->li_hist); 8277c657876SArnaldo Carvalho de Melo } 8287c657876SArnaldo Carvalho de Melo 8292babe1f6SArnaldo Carvalho de Melo static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info) 8302babe1f6SArnaldo Carvalho de Melo { 831b2e317f4SGerrit Renker info->tcpi_ca_state = ccid3_hc_rx_sk(sk)->state; 8322babe1f6SArnaldo Carvalho de Melo info->tcpi_options |= TCPI_OPT_TIMESTAMPS; 833b2e317f4SGerrit Renker info->tcpi_rcv_rtt = ccid3_hc_rx_sk(sk)->rtt; 8342babe1f6SArnaldo Carvalho de Melo } 8352babe1f6SArnaldo Carvalho de Melo 83688f964dbSArnaldo Carvalho de Melo static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len, 83788f964dbSArnaldo Carvalho de Melo u32 __user *optval, int __user *optlen) 83888f964dbSArnaldo Carvalho de Melo { 839b2e317f4SGerrit Renker const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk); 8408e138e79SGerrit Renker struct tfrc_rx_info rx_info; 84188f964dbSArnaldo Carvalho de Melo const void *val; 84288f964dbSArnaldo Carvalho de Melo 84388f964dbSArnaldo Carvalho de Melo switch (optname) { 84488f964dbSArnaldo Carvalho de Melo case DCCP_SOCKOPT_CCID_RX_INFO: 8458e138e79SGerrit Renker if (len < sizeof(rx_info)) 84688f964dbSArnaldo Carvalho de Melo return -EINVAL; 847842d1ef1SGerrit Renker rx_info.tfrcrx_x_recv = hcrx->x_recv; 848842d1ef1SGerrit Renker rx_info.tfrcrx_rtt = hcrx->rtt; 849535c55dfSGerrit Renker rx_info.tfrcrx_p = tfrc_invert_loss_event_rate(hcrx->p_inverse); 8508e138e79SGerrit Renker len = sizeof(rx_info); 8518e138e79SGerrit Renker val = &rx_info; 85288f964dbSArnaldo Carvalho de Melo break; 85388f964dbSArnaldo Carvalho de Melo default: 85488f964dbSArnaldo Carvalho de Melo return -ENOPROTOOPT; 85588f964dbSArnaldo Carvalho de Melo } 85688f964dbSArnaldo Carvalho de Melo 85788f964dbSArnaldo Carvalho de Melo if (put_user(len, optlen) || copy_to_user(optval, val, len)) 85888f964dbSArnaldo Carvalho de Melo return -EFAULT; 85988f964dbSArnaldo Carvalho de Melo 86088f964dbSArnaldo Carvalho de Melo return 0; 86188f964dbSArnaldo Carvalho de Melo } 86288f964dbSArnaldo Carvalho de Melo 86391f0ebf7SArnaldo Carvalho de Melo static struct ccid_operations ccid3 = { 8643dd9a7c3SIan McDonald .ccid_id = DCCPC_CCID3, 86584a97b0aSGerrit Renker .ccid_name = "TCP-Friendly Rate Control", 8667c657876SArnaldo Carvalho de Melo .ccid_owner = THIS_MODULE, 86791f0ebf7SArnaldo Carvalho de Melo .ccid_hc_tx_obj_size = sizeof(struct ccid3_hc_tx_sock), 8687c657876SArnaldo Carvalho de Melo .ccid_hc_tx_init = ccid3_hc_tx_init, 8697c657876SArnaldo Carvalho de Melo .ccid_hc_tx_exit = ccid3_hc_tx_exit, 8707c657876SArnaldo Carvalho de Melo .ccid_hc_tx_send_packet = ccid3_hc_tx_send_packet, 8717c657876SArnaldo Carvalho de Melo .ccid_hc_tx_packet_sent = ccid3_hc_tx_packet_sent, 8727c657876SArnaldo Carvalho de Melo .ccid_hc_tx_packet_recv = ccid3_hc_tx_packet_recv, 8737c657876SArnaldo Carvalho de Melo .ccid_hc_tx_parse_options = ccid3_hc_tx_parse_options, 87491f0ebf7SArnaldo Carvalho de Melo .ccid_hc_rx_obj_size = sizeof(struct ccid3_hc_rx_sock), 8757c657876SArnaldo Carvalho de Melo .ccid_hc_rx_init = ccid3_hc_rx_init, 8767c657876SArnaldo Carvalho de Melo .ccid_hc_rx_exit = ccid3_hc_rx_exit, 8777c657876SArnaldo Carvalho de Melo .ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options, 8787c657876SArnaldo Carvalho de Melo .ccid_hc_rx_packet_recv = ccid3_hc_rx_packet_recv, 8792babe1f6SArnaldo Carvalho de Melo .ccid_hc_rx_get_info = ccid3_hc_rx_get_info, 8802babe1f6SArnaldo Carvalho de Melo .ccid_hc_tx_get_info = ccid3_hc_tx_get_info, 88188f964dbSArnaldo Carvalho de Melo .ccid_hc_rx_getsockopt = ccid3_hc_rx_getsockopt, 88288f964dbSArnaldo Carvalho de Melo .ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt, 8837c657876SArnaldo Carvalho de Melo }; 8847c657876SArnaldo Carvalho de Melo 88556724aa4SGerrit Renker #ifdef CONFIG_IP_DCCP_CCID3_DEBUG 88643264991SGerrit Renker module_param(ccid3_debug, bool, 0644); 8877c657876SArnaldo Carvalho de Melo MODULE_PARM_DESC(ccid3_debug, "Enable debug messages"); 88856724aa4SGerrit Renker #endif 8897c657876SArnaldo Carvalho de Melo 8907c657876SArnaldo Carvalho de Melo static __init int ccid3_module_init(void) 8917c657876SArnaldo Carvalho de Melo { 89234a9e7eaSArnaldo Carvalho de Melo return ccid_register(&ccid3); 8937c657876SArnaldo Carvalho de Melo } 8947c657876SArnaldo Carvalho de Melo module_init(ccid3_module_init); 8957c657876SArnaldo Carvalho de Melo 8967c657876SArnaldo Carvalho de Melo static __exit void ccid3_module_exit(void) 8977c657876SArnaldo Carvalho de Melo { 8987c657876SArnaldo Carvalho de Melo ccid_unregister(&ccid3); 8997c657876SArnaldo Carvalho de Melo } 9007c657876SArnaldo Carvalho de Melo module_exit(ccid3_module_exit); 9017c657876SArnaldo Carvalho de Melo 902e6bccd35SIan McDonald MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>, " 9031f2333aeSArnaldo Carvalho de Melo "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>"); 9047c657876SArnaldo Carvalho de Melo MODULE_DESCRIPTION("DCCP TFRC CCID3 CCID"); 9057c657876SArnaldo Carvalho de Melo MODULE_LICENSE("GPL"); 9067c657876SArnaldo Carvalho de Melo MODULE_ALIAS("net-dccp-ccid-3"); 907