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Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -07001/*
2 * net/dccp/ccids/ccid3.c
3 *
Gerrit Renker954c2db2007-12-12 14:06:14 -02004 * Copyright (c) 2007 The University of Aberdeen, Scotland, UK
Ian McDonaldb2f41ff2007-05-28 12:23:29 -03005 * Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
6 * Copyright (c) 2005-7 Ian McDonald <ian.mcdonald@jandi.co.nz>
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -07007 *
8 * An implementation of the DCCP protocol
9 *
10 * This code has been developed by the University of Waikato WAND
11 * research group. For further information please see http://www.wand.net.nz/
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070012 *
13 * This code also uses code from Lulea University, rereleased as GPL by its
14 * authors:
15 * Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
16 *
17 * Changes to meet Linux coding standards, to make it meet latest ccid3 draft
18 * and to make it work as a loadable module in the DCCP stack written by
19 * Arnaldo Carvalho de Melo <acme@conectiva.com.br>.
20 *
21 * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
22 *
23 * This program is free software; you can redistribute it and/or modify
24 * it under the terms of the GNU General Public License as published by
25 * the Free Software Foundation; either version 2 of the License, or
26 * (at your option) any later version.
27 *
28 * This program is distributed in the hope that it will be useful,
29 * but WITHOUT ANY WARRANTY; without even the implied warranty of
30 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
31 * GNU General Public License for more details.
32 *
33 * You should have received a copy of the GNU General Public License
34 * along with this program; if not, write to the Free Software
35 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
36 */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070037#include "../dccp.h"
38#include "ccid3.h"
39
Gerrit Renker76fd1e82007-10-24 10:46:58 -020040#include <asm/unaligned.h>
41
Gerrit Renker56724aa2006-11-20 18:28:09 -020042#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
43static int ccid3_debug;
44#define ccid3_pr_debug(format, a...) DCCP_PR_DEBUG(ccid3_debug, format, ##a)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070045#else
46#define ccid3_pr_debug(format, a...)
47#endif
48
Gerrit Renker9bf17472007-03-20 13:11:24 -030049/*
50 * Transmitter Half-Connection Routines
51 */
Gerrit Renker56724aa2006-11-20 18:28:09 -020052#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070053static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state)
54{
55 static char *ccid3_state_names[] = {
56 [TFRC_SSTATE_NO_SENT] = "NO_SENT",
57 [TFRC_SSTATE_NO_FBACK] = "NO_FBACK",
58 [TFRC_SSTATE_FBACK] = "FBACK",
59 [TFRC_SSTATE_TERM] = "TERM",
60 };
61
62 return ccid3_state_names[state];
63}
64#endif
65
Arnaldo Carvalho de Meloc25a18b2006-03-20 21:58:56 -080066static void ccid3_hc_tx_set_state(struct sock *sk,
67 enum ccid3_hc_tx_states state)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070068{
Arnaldo Carvalho de Melo59725dc2005-09-09 02:40:58 -030069 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
Gerrit Renker842d1ef2008-09-04 07:30:19 +020070 enum ccid3_hc_tx_states oldstate = hctx->state;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070071
72 ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
Arnaldo Carvalho de Melo1f2333a2005-08-27 03:51:58 -030073 dccp_role(sk), sk, ccid3_tx_state_name(oldstate),
74 ccid3_tx_state_name(state));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070075 WARN_ON(state == oldstate);
Gerrit Renker842d1ef2008-09-04 07:30:19 +020076 hctx->state = state;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070077}
78
Gerrit Renker17893bc2006-11-27 20:31:33 -020079/*
Gerrit Renker6c08b2c2007-11-20 17:33:17 -020080 * Compute the initial sending rate X_init in the manner of RFC 3390:
81 *
82 * X_init = min(4 * s, max(2 * s, 4380 bytes)) / RTT
83 *
84 * Note that RFC 3390 uses MSS, RFC 4342 refers to RFC 3390, and rfc3448bis
85 * (rev-02) clarifies the use of RFC 3390 with regard to the above formula.
Gerrit Renkera21f9f92007-03-20 15:12:10 -030086 * For consistency with other parts of the code, X_init is scaled by 2^6.
87 */
88static inline u64 rfc3390_initial_rate(struct sock *sk)
89{
Gerrit Renker6c08b2c2007-11-20 17:33:17 -020090 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
Gerrit Renker842d1ef2008-09-04 07:30:19 +020091 const __u32 w_init = clamp_t(__u32, 4380U, 2 * hctx->s, 4 * hctx->s);
Gerrit Renkera21f9f92007-03-20 15:12:10 -030092
Gerrit Renker842d1ef2008-09-04 07:30:19 +020093 return scaled_div(w_init << 6, hctx->rtt);
Gerrit Renkera21f9f92007-03-20 15:12:10 -030094}
95
Gerrit Renkerde6f2b52008-09-04 07:30:19 +020096/**
97 * ccid3_update_send_interval - Calculate new t_ipi = s / X_inst
98 * This respects the granularity of X_inst (64 * bytes/second).
Gerrit Renker17893bc2006-11-27 20:31:33 -020099 */
Ilpo Järvinenc4e18da2008-01-05 23:13:58 -0800100static void ccid3_update_send_interval(struct ccid3_hc_tx_sock *hctx)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700101{
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200102 hctx->t_ipi = scaled_div32(((u64)hctx->s) << 6, hctx->x);
Gerrit Renker17893bc2006-11-27 20:31:33 -0200103
Gerrit Renkerde6f2b52008-09-04 07:30:19 +0200104 ccid3_pr_debug("t_ipi=%u, s=%u, X=%u\n", hctx->t_ipi,
105 hctx->s, (unsigned)(hctx->x >> 6));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700106}
Gerrit Renkeraa97efd2007-09-25 22:39:16 -0700107
Gerrit Renkera5358fd2007-11-20 18:01:59 -0200108static u32 ccid3_hc_tx_idle_rtt(struct ccid3_hc_tx_sock *hctx, ktime_t now)
109{
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200110 u32 delta = ktime_us_delta(now, hctx->t_last_win_count);
Gerrit Renkera5358fd2007-11-20 18:01:59 -0200111
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200112 return delta / hctx->rtt;
Gerrit Renkera5358fd2007-11-20 18:01:59 -0200113}
114
Gerrit Renkeraa97efd2007-09-25 22:39:16 -0700115/**
116 * ccid3_hc_tx_update_x - Update allowed sending rate X
117 * @stamp: most recent time if available - can be left NULL.
118 * This function tracks draft rfc3448bis, check there for latest details.
Gerrit Renker5c3fbb62006-12-03 14:50:56 -0200119 *
Gerrit Renker1a21e492006-12-10 00:02:12 -0200120 * Note: X and X_recv are both stored in units of 64 * bytes/second, to support
121 * fine-grained resolution of sending rates. This requires scaling by 2^6
122 * throughout the code. Only X_calc is unscaled (in bytes/second).
123 *
Gerrit Renker1a21e492006-12-10 00:02:12 -0200124 */
Gerrit Renkeraa97efd2007-09-25 22:39:16 -0700125static void ccid3_hc_tx_update_x(struct sock *sk, ktime_t *stamp)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700126{
Arnaldo Carvalho de Melo59725dc2005-09-09 02:40:58 -0300127 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200128 u64 min_rate = 2 * hctx->x_recv;
129 const u64 old_x = hctx->x;
Gerrit Renker52515e72007-12-17 12:57:43 -0200130 ktime_t now = stamp ? *stamp : ktime_get_real();
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700131
Gerrit Renker0c150ef2007-03-20 15:19:07 -0300132 /*
133 * Handle IDLE periods: do not reduce below RFC3390 initial sending rate
Gerrit Renkera5358fd2007-11-20 18:01:59 -0200134 * when idling [RFC 4342, 5.1]. Definition of idling is from rfc3448bis:
135 * a sender is idle if it has not sent anything over a 2-RTT-period.
Gerrit Renker0c150ef2007-03-20 15:19:07 -0300136 * For consistency with X and X_recv, min_rate is also scaled by 2^6.
137 */
Gerrit Renkera5358fd2007-11-20 18:01:59 -0200138 if (ccid3_hc_tx_idle_rtt(hctx, now) >= 2) {
Gerrit Renker0c150ef2007-03-20 15:19:07 -0300139 min_rate = rfc3390_initial_rate(sk);
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200140 min_rate = max(min_rate, 2 * hctx->x_recv);
Gerrit Renker0c150ef2007-03-20 15:19:07 -0300141 }
142
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200143 if (hctx->p > 0) {
Gerrit Renker1a21e492006-12-10 00:02:12 -0200144
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200145 hctx->x = min(((u64)hctx->x_calc) << 6, min_rate);
146 hctx->x = max(hctx->x, (((u64)hctx->s) << 6) / TFRC_T_MBI);
Arnaldo Carvalho de Melob6ee3d42005-08-27 18:18:18 -0300147
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200148 } else if (ktime_us_delta(now, hctx->t_ld) - (s64)hctx->rtt >= 0) {
Gerrit Renker1a21e492006-12-10 00:02:12 -0200149
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200150 hctx->x = min(2 * hctx->x, min_rate);
151 hctx->x = max(hctx->x,
152 scaled_div(((u64)hctx->s) << 6, hctx->rtt));
153 hctx->t_ld = now;
Gerrit Renkerff586292006-12-10 00:00:14 -0200154 }
Gerrit Renkera79ef762006-11-28 19:51:42 -0200155
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200156 if (hctx->x != old_x) {
Gerrit Renker1761f7d2007-03-20 15:04:30 -0300157 ccid3_pr_debug("X_prev=%u, X_now=%u, X_calc=%u, "
158 "X_recv=%u\n", (unsigned)(old_x >> 6),
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200159 (unsigned)(hctx->x >> 6), hctx->x_calc,
160 (unsigned)(hctx->x_recv >> 6));
Ian McDonald8699be72007-03-20 14:49:20 -0300161
Gerrit Renker1266ade2007-03-20 14:56:11 -0300162 ccid3_update_send_interval(hctx);
Ian McDonald8699be72007-03-20 14:49:20 -0300163 }
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700164}
165
Gerrit Renker78ad7132006-11-28 19:22:33 -0200166/*
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200167 * Track the mean packet size `s' (cf. RFC 4342, 5.3 and RFC 3448, 4.1)
168 * @len: DCCP packet payload size in bytes
Gerrit Renker78ad7132006-11-28 19:22:33 -0200169 */
170static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hctx, int len)
171{
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200172 const u16 old_s = hctx->s;
Gerrit Renker1266ade2007-03-20 14:56:11 -0300173
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200174 hctx->s = tfrc_ewma(hctx->s, len, 9);
Gerrit Renker1266ade2007-03-20 14:56:11 -0300175
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200176 if (hctx->s != old_s)
Gerrit Renker1266ade2007-03-20 14:56:11 -0300177 ccid3_update_send_interval(hctx);
Gerrit Renker78ad7132006-11-28 19:22:33 -0200178}
179
Gerrit Renker9f8681d2006-12-10 00:07:37 -0200180/*
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200181 * Update Window Counter using the algorithm from [RFC 4342, 8.1].
Gerrit Renker825de272008-05-27 06:33:54 -0700182 * As elsewhere, RTT > 0 is assumed by using dccp_sample_rtt().
Gerrit Renker9f8681d2006-12-10 00:07:37 -0200183 */
184static inline void ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock *hctx,
Gerrit Renker8132da42007-06-16 13:34:02 -0300185 ktime_t now)
Gerrit Renker9f8681d2006-12-10 00:07:37 -0200186{
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200187 u32 delta = ktime_us_delta(now, hctx->t_last_win_count),
188 quarter_rtts = (4 * delta) / hctx->rtt;
Gerrit Renker9f8681d2006-12-10 00:07:37 -0200189
190 if (quarter_rtts > 0) {
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200191 hctx->t_last_win_count = now;
192 hctx->last_win_count += min(quarter_rtts, 5U);
193 hctx->last_win_count &= 0xF; /* mod 16 */
Gerrit Renker9f8681d2006-12-10 00:07:37 -0200194 }
195}
196
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700197static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
198{
199 struct sock *sk = (struct sock *)data;
Arnaldo Carvalho de Melo59725dc2005-09-09 02:40:58 -0300200 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
Gerrit Renker2a1fda62006-11-28 18:34:34 -0200201 unsigned long t_nfb = USEC_PER_SEC / 5;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700202
203 bh_lock_sock(sk);
204 if (sock_owned_by_user(sk)) {
205 /* Try again later. */
206 /* XXX: set some sensible MIB */
Gerrit Renker48e03ee2006-11-27 20:29:27 -0200207 goto restart_timer;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700208 }
209
Gerrit Renkera9672412006-12-10 00:14:12 -0200210 ccid3_pr_debug("%s(%p, state=%s) - entry \n", dccp_role(sk), sk,
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200211 ccid3_tx_state_name(hctx->state));
Gerrit Renkera9672412006-12-10 00:14:12 -0200212
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200213 if (hctx->state == TFRC_SSTATE_FBACK)
Gerrit Renker52515e72007-12-17 12:57:43 -0200214 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200215 else if (hctx->state != TFRC_SSTATE_NO_FBACK)
Gerrit Renker52515e72007-12-17 12:57:43 -0200216 goto out;
217
218 /*
219 * Determine new allowed sending rate X as per draft rfc3448bis-00, 4.4
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200220 * RTO is 0 if and only if no feedback has been received yet.
Gerrit Renker52515e72007-12-17 12:57:43 -0200221 */
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200222 if (hctx->t_rto == 0 || hctx->p == 0) {
Gerrit Renker52515e72007-12-17 12:57:43 -0200223
224 /* halve send rate directly */
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200225 hctx->x = max(hctx->x / 2, (((u64)hctx->s) << 6) / TFRC_T_MBI);
Gerrit Renker1266ade2007-03-20 14:56:11 -0300226 ccid3_update_send_interval(hctx);
Gerrit Renker52515e72007-12-17 12:57:43 -0200227 } else {
Arnaldo Carvalho de Melo1f2333a2005-08-27 03:51:58 -0300228 /*
Gerrit Renker52515e72007-12-17 12:57:43 -0200229 * Modify the cached value of X_recv
Gerrit Renker0c150ef2007-03-20 15:19:07 -0300230 *
Gerrit Renker52515e72007-12-17 12:57:43 -0200231 * If (X_calc > 2 * X_recv)
Gerrit Renker0c150ef2007-03-20 15:19:07 -0300232 * X_recv = max(X_recv / 2, s / (2 * t_mbi));
233 * Else
234 * X_recv = X_calc / 4;
235 *
236 * Note that X_recv is scaled by 2^6 while X_calc is not
Arnaldo Carvalho de Melo1f2333a2005-08-27 03:51:58 -0300237 */
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200238 BUG_ON(hctx->p && !hctx->x_calc);
Gerrit Renkera79ef762006-11-28 19:51:42 -0200239
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200240 if (hctx->x_calc > (hctx->x_recv >> 5))
241 hctx->x_recv =
242 max(hctx->x_recv / 2,
243 (((__u64)hctx->s) << 6) / (2 * TFRC_T_MBI));
Gerrit Renker52515e72007-12-17 12:57:43 -0200244 else {
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200245 hctx->x_recv = hctx->x_calc;
246 hctx->x_recv <<= 4;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700247 }
Gerrit Renkeraa97efd2007-09-25 22:39:16 -0700248 ccid3_hc_tx_update_x(sk, NULL);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700249 }
Gerrit Renker52515e72007-12-17 12:57:43 -0200250 ccid3_pr_debug("Reduced X to %llu/64 bytes/sec\n",
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200251 (unsigned long long)hctx->x);
Gerrit Renker52515e72007-12-17 12:57:43 -0200252
253 /*
254 * Set new timeout for the nofeedback timer.
255 * See comments in packet_recv() regarding the value of t_RTO.
256 */
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200257 if (unlikely(hctx->t_rto == 0)) /* no feedback received yet */
Gerrit Renker52515e72007-12-17 12:57:43 -0200258 t_nfb = TFRC_INITIAL_TIMEOUT;
259 else
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200260 t_nfb = max(hctx->t_rto, 2 * hctx->t_ipi);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700261
Gerrit Renker48e03ee2006-11-27 20:29:27 -0200262restart_timer:
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200263 sk_reset_timer(sk, &hctx->no_feedback_timer,
YOSHIFUJI Hideakic9eaf172007-02-09 23:24:38 +0900264 jiffies + usecs_to_jiffies(t_nfb));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700265out:
266 bh_unlock_sock(sk);
267 sock_put(sk);
268}
269
Gerrit Renker7da7f452006-11-27 12:26:03 -0200270/*
271 * returns
272 * > 0: delay (in msecs) that should pass before actually sending
273 * = 0: can send immediately
274 * < 0: error condition; do not send packet
275 */
Gerrit Renker6b57c932006-11-28 19:55:06 -0200276static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700277{
278 struct dccp_sock *dp = dccp_sk(sk);
Arnaldo Carvalho de Melo59725dc2005-09-09 02:40:58 -0300279 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
Gerrit Renker8132da42007-06-16 13:34:02 -0300280 ktime_t now = ktime_get_real();
281 s64 delay;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700282
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700283 /*
Gerrit Renkerda335ba2006-11-27 12:26:57 -0200284 * This function is called only for Data and DataAck packets. Sending
285 * zero-sized Data(Ack)s is theoretically possible, but for congestion
286 * control this case is pathological - ignore it.
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700287 */
Gerrit Renker6b57c932006-11-28 19:55:06 -0200288 if (unlikely(skb->len == 0))
Gerrit Renkerda335ba2006-11-27 12:26:57 -0200289 return -EBADMSG;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700290
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200291 switch (hctx->state) {
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700292 case TFRC_SSTATE_NO_SENT:
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200293 sk_reset_timer(sk, &hctx->no_feedback_timer, (jiffies +
YOSHIFUJI Hideakic9eaf172007-02-09 23:24:38 +0900294 usecs_to_jiffies(TFRC_INITIAL_TIMEOUT)));
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200295 hctx->last_win_count = 0;
296 hctx->t_last_win_count = now;
Gerrit Renker90feeb92006-11-27 12:13:38 -0200297
298 /* Set t_0 for initial packet */
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200299 hctx->t_nom = now;
Gerrit Renker30833ff2007-03-20 15:31:56 -0300300
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200301 hctx->s = skb->len;
Gerrit Renker30833ff2007-03-20 15:31:56 -0300302
303 /*
304 * Use initial RTT sample when available: recommended by erratum
305 * to RFC 4342. This implements the initialisation procedure of
306 * draft rfc3448bis, section 4.2. Remember, X is scaled by 2^6.
307 */
308 if (dp->dccps_syn_rtt) {
309 ccid3_pr_debug("SYN RTT = %uus\n", dp->dccps_syn_rtt);
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200310 hctx->rtt = dp->dccps_syn_rtt;
311 hctx->x = rfc3390_initial_rate(sk);
312 hctx->t_ld = now;
Gerrit Renker30833ff2007-03-20 15:31:56 -0300313 } else {
Gerrit Renker3294f202008-06-11 11:19:09 +0100314 /*
315 * Sender does not have RTT sample:
316 * - set fallback RTT (RFC 4340, 3.4) since a RTT value
317 * is needed in several parts (e.g. window counter);
318 * - set sending rate X_pps = 1pps as per RFC 3448, 4.2.
319 */
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200320 hctx->rtt = DCCP_FALLBACK_RTT;
321 hctx->x = hctx->s;
322 hctx->x <<= 6;
Gerrit Renker30833ff2007-03-20 15:31:56 -0300323 }
324 ccid3_update_send_interval(hctx);
325
326 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700327 break;
328 case TFRC_SSTATE_NO_FBACK:
329 case TFRC_SSTATE_FBACK:
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200330 delay = ktime_us_delta(hctx->t_nom, now);
Ian McDonald8699be72007-03-20 14:49:20 -0300331 ccid3_pr_debug("delay=%ld\n", (long)delay);
Gerrit Renker91cf5a12006-11-27 12:25:10 -0200332 /*
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200333 * Scheduling of packet transmissions [RFC 3448, 4.6]
Gerrit Renker91cf5a12006-11-27 12:25:10 -0200334 *
335 * if (t_now > t_nom - delta)
336 * // send the packet now
337 * else
338 * // send the packet in (t_nom - t_now) milliseconds.
339 */
Gerrit Renkerde6f2b52008-09-04 07:30:19 +0200340 if (delay >= TFRC_T_DELTA)
341 return (u32)delay / USEC_PER_MSEC;
Gerrit Renker9f8681d2006-12-10 00:07:37 -0200342
Gerrit Renker8132da42007-06-16 13:34:02 -0300343 ccid3_hc_tx_update_win_count(hctx, now);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700344 break;
Gerrit Renker59348b12006-11-20 18:39:23 -0200345 case TFRC_SSTATE_TERM:
Gerrit Renkera9672412006-12-10 00:14:12 -0200346 DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
Gerrit Renker7da7f452006-11-27 12:26:03 -0200347 return -EINVAL;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700348 }
349
Gerrit Renker7da7f452006-11-27 12:26:03 -0200350 /* prepare to send now (add options etc.) */
351 dp->dccps_hc_tx_insert_options = 1;
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200352 DCCP_SKB_CB(skb)->dccpd_ccval = hctx->last_win_count;
Gerrit Renkere312d102006-12-10 00:08:09 -0200353
354 /* set the nominal send time for the next following packet */
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200355 hctx->t_nom = ktime_add_us(hctx->t_nom, hctx->t_ipi);
Gerrit Renker7da7f452006-11-27 12:26:03 -0200356 return 0;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700357}
358
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200359static void ccid3_hc_tx_packet_sent(struct sock *sk, int more,
360 unsigned int len)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700361{
Arnaldo Carvalho de Melo59725dc2005-09-09 02:40:58 -0300362 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700363
Gerrit Renker6b57c932006-11-28 19:55:06 -0200364 ccid3_hc_tx_update_s(hctx, len);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700365
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200366 if (tfrc_tx_hist_add(&hctx->hist, dccp_sk(sk)->dccps_gss))
Gerrit Renkerc5a1ae92006-12-10 00:09:21 -0200367 DCCP_CRIT("packet history - out of memory!");
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700368}
369
370static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
371{
Arnaldo Carvalho de Melo59725dc2005-09-09 02:40:58 -0300372 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200373 struct ccid3_options_received *opt_recv = &hctx->options_received;
Gerrit Renker63b3a732008-09-04 07:30:19 +0200374 struct tfrc_tx_hist_entry *acked;
Arnaldo Carvalho de Melo0740d492007-08-19 17:18:13 -0700375 ktime_t now;
Gerrit Renker2a1fda62006-11-28 18:34:34 -0200376 unsigned long t_nfb;
Gerrit Renker7dfee1a2007-03-20 15:24:37 -0300377 u32 pinv, r_sample;
Arnaldo Carvalho de Melo1f2333a2005-08-27 03:51:58 -0300378
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700379 /* we are only interested in ACKs */
380 if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
381 DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
382 return;
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200383 /* ... and only in the established state */
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200384 if (hctx->state != TFRC_SSTATE_FBACK &&
385 hctx->state != TFRC_SSTATE_NO_FBACK)
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200386 return;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700387
Gerrit Renker63b3a732008-09-04 07:30:19 +0200388 /*
389 * Locate the acknowledged packet in the TX history.
390 *
391 * Returning "entry not found" here can for instance happen when
392 * - the host has not sent out anything (e.g. a passive server),
393 * - the Ack is outdated (packet with higher Ack number was received),
394 * - it is a bogus Ack (for a packet not sent on this connection).
395 */
396 acked = tfrc_tx_hist_find_entry(hctx->hist, dccp_hdr_ack_seq(skb));
397 if (acked == NULL)
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200398 return;
Gerrit Renker63b3a732008-09-04 07:30:19 +0200399 /* For the sake of RTT sampling, ignore/remove all older entries */
400 tfrc_tx_hist_purge(&acked->next);
401
402 /* Update the moving average for the RTT estimate (RFC 3448, 4.3) */
403 now = ktime_get_real();
404 r_sample = dccp_sample_rtt(sk, ktime_us_delta(now, acked->stamp));
405 hctx->rtt = tfrc_ewma(hctx->rtt, r_sample, 9);
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200406
407 /* Update receive rate in units of 64 * bytes/second */
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200408 hctx->x_recv = opt_recv->ccid3or_receive_rate;
409 hctx->x_recv <<= 6;
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200410
411 /* Update loss event rate (which is scaled by 1e6) */
412 pinv = opt_recv->ccid3or_loss_event_rate;
413 if (pinv == ~0U || pinv == 0) /* see RFC 4342, 8.5 */
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200414 hctx->p = 0;
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200415 else /* can not exceed 100% */
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200416 hctx->p = scaled_div(1, pinv);
Gerrit Renker63b3a732008-09-04 07:30:19 +0200417
Gerrit Renkerd8d12522007-12-17 12:48:47 -0200418 /*
419 * Update allowed sending rate X as per draft rfc3448bis-00, 4.2/3
420 */
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200421 if (hctx->state == TFRC_SSTATE_NO_FBACK) {
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200422 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200423
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200424 if (hctx->t_rto == 0) {
Gerrit Renkerd8d12522007-12-17 12:48:47 -0200425 /*
426 * Initial feedback packet: Larger Initial Windows (4.2)
427 */
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200428 hctx->x = rfc3390_initial_rate(sk);
429 hctx->t_ld = now;
Gerrit Renkerd8d12522007-12-17 12:48:47 -0200430
431 ccid3_update_send_interval(hctx);
432
433 goto done_computing_x;
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200434 } else if (hctx->p == 0) {
Gerrit Renkerd8d12522007-12-17 12:48:47 -0200435 /*
436 * First feedback after nofeedback timer expiry (4.3)
437 */
438 goto done_computing_x;
439 }
440 }
441
442 /* Update sending rate (step 4 of [RFC 3448, 4.3]) */
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200443 if (hctx->p > 0)
444 hctx->x_calc = tfrc_calc_x(hctx->s, hctx->rtt, hctx->p);
Gerrit Renkerd8d12522007-12-17 12:48:47 -0200445 ccid3_hc_tx_update_x(sk, &now);
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200446
Gerrit Renkerd8d12522007-12-17 12:48:47 -0200447done_computing_x:
448 ccid3_pr_debug("%s(%p), RTT=%uus (sample=%uus), s=%u, "
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200449 "p=%u, X_calc=%u, X_recv=%u, X=%u\n",
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200450 dccp_role(sk), sk, hctx->rtt, r_sample,
451 hctx->s, hctx->p, hctx->x_calc,
452 (unsigned)(hctx->x_recv >> 6),
453 (unsigned)(hctx->x >> 6));
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200454
455 /* unschedule no feedback timer */
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200456 sk_stop_timer(sk, &hctx->no_feedback_timer);
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200457
458 /*
459 * As we have calculated new ipi, delta, t_nom it is possible
460 * that we now can send a packet, so wake up dccp_wait_for_ccid
461 */
462 sk->sk_write_space(sk);
463
464 /*
465 * Update timeout interval for the nofeedback timer.
466 * We use a configuration option to increase the lower bound.
467 * This can help avoid triggering the nofeedback timer too
468 * often ('spinning') on LANs with small RTTs.
469 */
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200470 hctx->t_rto = max_t(u32, 4 * hctx->rtt, (CONFIG_IP_DCCP_CCID3_RTO *
471 (USEC_PER_SEC / 1000)));
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200472 /*
473 * Schedule no feedback timer to expire in
474 * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
475 */
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200476 t_nfb = max(hctx->t_rto, 2 * hctx->t_ipi);
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200477
478 ccid3_pr_debug("%s(%p), Scheduled no feedback timer to "
479 "expire in %lu jiffies (%luus)\n",
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200480 dccp_role(sk), sk, usecs_to_jiffies(t_nfb), t_nfb);
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200481
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200482 sk_reset_timer(sk, &hctx->no_feedback_timer,
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200483 jiffies + usecs_to_jiffies(t_nfb));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700484}
485
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700486static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
Arnaldo Carvalho de Melo1f2333a2005-08-27 03:51:58 -0300487 unsigned char len, u16 idx,
488 unsigned char *value)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700489{
Arnaldo Carvalho de Melo59725dc2005-09-09 02:40:58 -0300490 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200491 struct ccid3_options_received *opt_recv = &hctx->options_received;
Gerrit Renker76fd1e82007-10-24 10:46:58 -0200492 __be32 opt_val;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700493
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700494 switch (option) {
Gerrit Renker47a61e72008-09-04 07:30:19 +0200495 case TFRC_OPT_RECEIVE_RATE:
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700496 case TFRC_OPT_LOSS_EVENT_RATE:
Arnaldo Carvalho de Melo59d203f2005-09-09 20:01:25 -0300497 if (unlikely(len != 4)) {
Gerrit Renker47a61e72008-09-04 07:30:19 +0200498 DCCP_WARN("%s(%p), invalid len %d for %u\n",
499 dccp_role(sk), sk, len, option);
500 return -EINVAL;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700501 }
Gerrit Renker47a61e72008-09-04 07:30:19 +0200502 opt_val = ntohl(get_unaligned((__be32 *)value));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700503
Gerrit Renker47a61e72008-09-04 07:30:19 +0200504 if (option == TFRC_OPT_RECEIVE_RATE) {
505 opt_recv->ccid3or_receive_rate = opt_val;
506 ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n",
507 dccp_role(sk), sk, opt_val);
508 } else {
509 opt_recv->ccid3or_loss_event_rate = opt_val;
510 ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n",
511 dccp_role(sk), sk, opt_val);
512 }
513 }
514 return 0;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700515}
516
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800517static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700518{
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800519 struct ccid3_hc_tx_sock *hctx = ccid_priv(ccid);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700520
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200521 hctx->state = TFRC_SSTATE_NO_SENT;
522 hctx->hist = NULL;
523 setup_timer(&hctx->no_feedback_timer,
524 ccid3_hc_tx_no_feedback_timer, (unsigned long)sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700525 return 0;
526}
527
528static void ccid3_hc_tx_exit(struct sock *sk)
529{
Arnaldo Carvalho de Melo59725dc2005-09-09 02:40:58 -0300530 struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700531
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700532 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM);
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200533 sk_stop_timer(sk, &hctx->no_feedback_timer);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700534
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200535 tfrc_tx_hist_purge(&hctx->hist);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700536}
537
Gerrit Renker9bf17472007-03-20 13:11:24 -0300538static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info)
539{
Gerrit Renkerb2e317f2008-09-04 07:30:19 +0200540 info->tcpi_rto = ccid3_hc_tx_sk(sk)->t_rto;
541 info->tcpi_rtt = ccid3_hc_tx_sk(sk)->rtt;
Gerrit Renker9bf17472007-03-20 13:11:24 -0300542}
543
544static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
545 u32 __user *optval, int __user *optlen)
546{
Gerrit Renkerb2e317f2008-09-04 07:30:19 +0200547 const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200548 struct tfrc_tx_info tfrc;
Gerrit Renker9bf17472007-03-20 13:11:24 -0300549 const void *val;
550
Gerrit Renker9bf17472007-03-20 13:11:24 -0300551 switch (optname) {
552 case DCCP_SOCKOPT_CCID_TX_INFO:
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200553 if (len < sizeof(tfrc))
Gerrit Renker9bf17472007-03-20 13:11:24 -0300554 return -EINVAL;
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200555 tfrc.tfrctx_x = hctx->x;
556 tfrc.tfrctx_x_recv = hctx->x_recv;
557 tfrc.tfrctx_x_calc = hctx->x_calc;
558 tfrc.tfrctx_rtt = hctx->rtt;
559 tfrc.tfrctx_p = hctx->p;
560 tfrc.tfrctx_rto = hctx->t_rto;
561 tfrc.tfrctx_ipi = hctx->t_ipi;
562 len = sizeof(tfrc);
563 val = &tfrc;
Gerrit Renker9bf17472007-03-20 13:11:24 -0300564 break;
565 default:
566 return -ENOPROTOOPT;
567 }
568
569 if (put_user(len, optlen) || copy_to_user(optval, val, len))
570 return -EFAULT;
571
572 return 0;
573}
574
575/*
576 * Receiver Half-Connection Routines
577 */
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200578
579/* CCID3 feedback types */
580enum ccid3_fback_type {
581 CCID3_FBACK_NONE = 0,
582 CCID3_FBACK_INITIAL,
583 CCID3_FBACK_PERIODIC,
584 CCID3_FBACK_PARAM_CHANGE
585};
586
Gerrit Renker56724aa2006-11-20 18:28:09 -0200587#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700588static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
589{
590 static char *ccid3_rx_state_names[] = {
591 [TFRC_RSTATE_NO_DATA] = "NO_DATA",
592 [TFRC_RSTATE_DATA] = "DATA",
593 [TFRC_RSTATE_TERM] = "TERM",
594 };
595
596 return ccid3_rx_state_names[state];
597}
598#endif
599
Arnaldo Carvalho de Meloc25a18b2006-03-20 21:58:56 -0800600static void ccid3_hc_rx_set_state(struct sock *sk,
601 enum ccid3_hc_rx_states state)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700602{
Arnaldo Carvalho de Melo59725dc2005-09-09 02:40:58 -0300603 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200604 enum ccid3_hc_rx_states oldstate = hcrx->state;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700605
606 ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
Arnaldo Carvalho de Melo1f2333a2005-08-27 03:51:58 -0300607 dccp_role(sk), sk, ccid3_rx_state_name(oldstate),
608 ccid3_rx_state_name(state));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700609 WARN_ON(state == oldstate);
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200610 hcrx->state = state;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700611}
612
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200613static void ccid3_hc_rx_send_feedback(struct sock *sk,
614 const struct sk_buff *skb,
615 enum ccid3_fback_type fbtype)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700616{
Arnaldo Carvalho de Melo59725dc2005-09-09 02:40:58 -0300617 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700618 struct dccp_sock *dp = dccp_sk(sk);
Arnaldo Carvalho de Meloe7c23352007-08-19 17:17:51 -0700619 ktime_t now;
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200620 s64 delta = 0;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700621
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200622 if (unlikely(hcrx->state == TFRC_RSTATE_TERM))
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200623 return;
624
Arnaldo Carvalho de Meloe7a81c62007-08-19 17:15:37 -0700625 now = ktime_get_real();
Arnaldo Carvalho de Melob6ee3d42005-08-27 18:18:18 -0300626
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200627 switch (fbtype) {
628 case CCID3_FBACK_INITIAL:
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200629 hcrx->x_recv = 0;
630 hcrx->p_inverse = ~0U; /* see RFC 4342, 8.5 */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700631 break;
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200632 case CCID3_FBACK_PARAM_CHANGE:
633 /*
634 * When parameters change (new loss or p > p_prev), we do not
635 * have a reliable estimate for R_m of [RFC 3448, 6.2] and so
636 * need to reuse the previous value of X_recv. However, when
637 * X_recv was 0 (due to early loss), this would kill X down to
638 * s/t_mbi (i.e. one packet in 64 seconds).
639 * To avoid such drastic reduction, we approximate X_recv as
640 * the number of bytes since last feedback.
641 * This is a safe fallback, since X is bounded above by X_calc.
642 */
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200643 if (hcrx->x_recv > 0)
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200644 break;
645 /* fall through */
646 case CCID3_FBACK_PERIODIC:
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200647 delta = ktime_us_delta(now, hcrx->tstamp_last_feedback);
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200648 if (delta <= 0)
649 DCCP_BUG("delta (%ld) <= 0", (long)delta);
650 else
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200651 hcrx->x_recv = scaled_div32(hcrx->bytes_recv, delta);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700652 break;
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200653 default:
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700654 return;
655 }
656
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200657 ccid3_pr_debug("Interval %ldusec, X_recv=%u, 1/p=%u\n",
658 (long)delta, hcrx->x_recv, hcrx->p_inverse);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700659
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200660 hcrx->tstamp_last_feedback = now;
661 hcrx->last_counter = dccp_hdr(skb)->dccph_ccval;
662 hcrx->bytes_recv = 0;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700663
Arnaldo Carvalho de Melo507d37c2005-09-09 02:30:07 -0300664 dp->dccps_hc_rx_insert_options = 1;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700665 dccp_send_ack(sk);
666}
667
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -0800668static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700669{
Gerrit Renkerb2e317f2008-09-04 07:30:19 +0200670 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
Andrea Bittau60fe62e2006-03-20 19:23:32 -0800671 __be32 x_recv, pinv;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700672
Arnaldo Carvalho de Melo59d203f2005-09-09 20:01:25 -0300673 if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -0800674 return 0;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700675
Arnaldo Carvalho de Melo4fded332005-08-23 21:51:59 -0700676 if (dccp_packet_without_ack(skb))
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -0800677 return 0;
678
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200679 x_recv = htonl(hcrx->x_recv);
680 pinv = htonl(hcrx->p_inverse);
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -0800681
Gerrit Renker385ac2e2007-12-08 16:26:59 -0200682 if (dccp_insert_option(sk, skb, TFRC_OPT_LOSS_EVENT_RATE,
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200683 &pinv, sizeof(pinv)) ||
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -0800684 dccp_insert_option(sk, skb, TFRC_OPT_RECEIVE_RATE,
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200685 &x_recv, sizeof(x_recv)))
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -0800686 return -1;
687
688 return 0;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700689}
690
Gerrit Renker954c2db2007-12-12 14:06:14 -0200691/** ccid3_first_li - Implements [RFC 3448, 6.3.1]
692 *
693 * Determine the length of the first loss interval via inverse lookup.
694 * Assume that X_recv can be computed by the throughput equation
695 * s
696 * X_recv = --------
697 * R * fval
698 * Find some p such that f(p) = fval; return 1/p (scaled).
699 */
700static u32 ccid3_first_li(struct sock *sk)
701{
702 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
703 u32 x_recv, p, delta;
704 u64 fval;
705
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200706 if (hcrx->rtt == 0) {
Gerrit Renker954c2db2007-12-12 14:06:14 -0200707 DCCP_WARN("No RTT estimate available, using fallback RTT\n");
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200708 hcrx->rtt = DCCP_FALLBACK_RTT;
Gerrit Renker954c2db2007-12-12 14:06:14 -0200709 }
710
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200711 delta = ktime_to_us(net_timedelta(hcrx->tstamp_last_feedback));
712 x_recv = scaled_div32(hcrx->bytes_recv, delta);
Gerrit Renker954c2db2007-12-12 14:06:14 -0200713 if (x_recv == 0) { /* would also trigger divide-by-zero */
714 DCCP_WARN("X_recv==0\n");
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200715 if (hcrx->x_recv == 0) {
Gerrit Renker954c2db2007-12-12 14:06:14 -0200716 DCCP_BUG("stored value of X_recv is zero");
717 return ~0U;
718 }
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200719 x_recv = hcrx->x_recv;
Gerrit Renker954c2db2007-12-12 14:06:14 -0200720 }
721
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200722 fval = scaled_div(hcrx->s, hcrx->rtt);
Gerrit Renker954c2db2007-12-12 14:06:14 -0200723 fval = scaled_div32(fval, x_recv);
724 p = tfrc_calc_x_reverse_lookup(fval);
725
726 ccid3_pr_debug("%s(%p), receive rate=%u bytes/s, implied "
727 "loss rate=%u\n", dccp_role(sk), sk, x_recv, p);
728
729 return p == 0 ? ~0U : scaled_div(1, p);
730}
731
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700732static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
733{
Arnaldo Carvalho de Melo59725dc2005-09-09 02:40:58 -0300734 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200735 enum ccid3_fback_type do_feedback = CCID3_FBACK_NONE;
Gerrit Renker5b5d0e72008-07-13 11:51:40 +0100736 const u64 ndp = dccp_sk(sk)->dccps_options_received.dccpor_ndp;
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200737 const bool is_data_packet = dccp_data_packet(skb);
Arnaldo Carvalho de Melo1f2333a2005-08-27 03:51:58 -0300738
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200739 if (unlikely(hcrx->state == TFRC_RSTATE_NO_DATA)) {
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200740 if (is_data_packet) {
741 const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4;
742 do_feedback = CCID3_FBACK_INITIAL;
743 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA);
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200744 hcrx->s = payload;
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200745 /*
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200746 * Not necessary to update bytes_recv here,
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200747 * since X_recv = 0 for the first feedback packet (cf.
748 * RFC 3448, 6.3) -- gerrit
749 */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700750 }
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200751 goto update_records;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700752 }
753
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200754 if (tfrc_rx_hist_duplicate(&hcrx->hist, skb))
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200755 return; /* done receiving */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700756
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200757 if (is_data_packet) {
758 const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4;
759 /*
760 * Update moving-average of s and the sum of received payload bytes
761 */
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200762 hcrx->s = tfrc_ewma(hcrx->s, payload, 9);
763 hcrx->bytes_recv += payload;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700764 }
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200765
766 /*
Gerrit Renkerb552c622008-07-13 11:51:40 +0100767 * Perform loss detection and handle pending losses
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200768 */
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200769 if (tfrc_rx_handle_loss(&hcrx->hist, &hcrx->li_hist,
Gerrit Renkerb552c622008-07-13 11:51:40 +0100770 skb, ndp, ccid3_first_li, sk)) {
Gerrit Renker954c2db2007-12-12 14:06:14 -0200771 do_feedback = CCID3_FBACK_PARAM_CHANGE;
772 goto done_receiving;
773 }
774
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200775 if (tfrc_rx_hist_loss_pending(&hcrx->hist))
Gerrit Renkerb552c622008-07-13 11:51:40 +0100776 return; /* done receiving */
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200777
778 /*
779 * Handle data packets: RTT sampling and monitoring p
780 */
781 if (unlikely(!is_data_packet))
782 goto update_records;
783
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200784 if (!tfrc_lh_is_initialised(&hcrx->li_hist)) {
785 const u32 sample = tfrc_rx_hist_sample_rtt(&hcrx->hist, skb);
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200786 /*
787 * Empty loss history: no loss so far, hence p stays 0.
788 * Sample RTT values, since an RTT estimate is required for the
789 * computation of p when the first loss occurs; RFC 3448, 6.3.1.
790 */
791 if (sample != 0)
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200792 hcrx->rtt = tfrc_ewma(hcrx->rtt, sample, 9);
Gerrit Renker954c2db2007-12-12 14:06:14 -0200793
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200794 } else if (tfrc_lh_update_i_mean(&hcrx->li_hist, skb)) {
Gerrit Renker954c2db2007-12-12 14:06:14 -0200795 /*
796 * Step (3) of [RFC 3448, 6.1]: Recompute I_mean and, if I_mean
797 * has decreased (resp. p has increased), send feedback now.
798 */
799 do_feedback = CCID3_FBACK_PARAM_CHANGE;
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200800 }
801
802 /*
803 * Check if the periodic once-per-RTT feedback is due; RFC 4342, 10.3
804 */
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200805 if (SUB16(dccp_hdr(skb)->dccph_ccval, hcrx->last_counter) > 3)
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200806 do_feedback = CCID3_FBACK_PERIODIC;
807
808update_records:
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200809 tfrc_rx_hist_add_packet(&hcrx->hist, skb, ndp);
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200810
Gerrit Renker954c2db2007-12-12 14:06:14 -0200811done_receiving:
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200812 if (do_feedback)
813 ccid3_hc_rx_send_feedback(sk, skb, do_feedback);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700814}
815
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800816static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700817{
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800818 struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700819
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200820 hcrx->state = TFRC_RSTATE_NO_DATA;
821 tfrc_lh_init(&hcrx->li_hist);
822 return tfrc_rx_hist_alloc(&hcrx->hist);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700823}
824
825static void ccid3_hc_rx_exit(struct sock *sk)
826{
Arnaldo Carvalho de Melo59725dc2005-09-09 02:40:58 -0300827 struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700828
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700829 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM);
830
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200831 tfrc_rx_hist_purge(&hcrx->hist);
832 tfrc_lh_cleanup(&hcrx->li_hist);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700833}
834
Arnaldo Carvalho de Melo2babe1f2005-08-23 21:52:35 -0700835static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
836{
Gerrit Renkerb2e317f2008-09-04 07:30:19 +0200837 info->tcpi_ca_state = ccid3_hc_rx_sk(sk)->state;
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200838 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
Gerrit Renkerb2e317f2008-09-04 07:30:19 +0200839 info->tcpi_rcv_rtt = ccid3_hc_rx_sk(sk)->rtt;
Arnaldo Carvalho de Melo2babe1f2005-08-23 21:52:35 -0700840}
841
Arnaldo Carvalho de Melo88f964d2005-09-18 00:19:32 -0700842static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len,
843 u32 __user *optval, int __user *optlen)
844{
Gerrit Renkerb2e317f2008-09-04 07:30:19 +0200845 const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
Gerrit Renker8e138e72007-12-17 10:07:44 -0200846 struct tfrc_rx_info rx_info;
Arnaldo Carvalho de Melo88f964d2005-09-18 00:19:32 -0700847 const void *val;
YOSHIFUJI Hideakic9eaf172007-02-09 23:24:38 +0900848
Arnaldo Carvalho de Melo88f964d2005-09-18 00:19:32 -0700849 switch (optname) {
850 case DCCP_SOCKOPT_CCID_RX_INFO:
Gerrit Renker8e138e72007-12-17 10:07:44 -0200851 if (len < sizeof(rx_info))
Arnaldo Carvalho de Melo88f964d2005-09-18 00:19:32 -0700852 return -EINVAL;
Gerrit Renker842d1ef2008-09-04 07:30:19 +0200853 rx_info.tfrcrx_x_recv = hcrx->x_recv;
854 rx_info.tfrcrx_rtt = hcrx->rtt;
855 rx_info.tfrcrx_p = hcrx->p_inverse == 0 ? ~0U :
856 scaled_div(1, hcrx->p_inverse);
Gerrit Renker8e138e72007-12-17 10:07:44 -0200857 len = sizeof(rx_info);
858 val = &rx_info;
Arnaldo Carvalho de Melo88f964d2005-09-18 00:19:32 -0700859 break;
860 default:
861 return -ENOPROTOOPT;
862 }
863
864 if (put_user(len, optlen) || copy_to_user(optval, val, len))
865 return -EFAULT;
866
867 return 0;
868}
869
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800870static struct ccid_operations ccid3 = {
Ian McDonald3dd9a7c2006-09-22 14:26:44 +1200871 .ccid_id = DCCPC_CCID3,
Gerrit Renker84a97b02007-12-13 23:33:25 -0200872 .ccid_name = "TCP-Friendly Rate Control",
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700873 .ccid_owner = THIS_MODULE,
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800874 .ccid_hc_tx_obj_size = sizeof(struct ccid3_hc_tx_sock),
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700875 .ccid_hc_tx_init = ccid3_hc_tx_init,
876 .ccid_hc_tx_exit = ccid3_hc_tx_exit,
877 .ccid_hc_tx_send_packet = ccid3_hc_tx_send_packet,
878 .ccid_hc_tx_packet_sent = ccid3_hc_tx_packet_sent,
879 .ccid_hc_tx_packet_recv = ccid3_hc_tx_packet_recv,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700880 .ccid_hc_tx_parse_options = ccid3_hc_tx_parse_options,
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800881 .ccid_hc_rx_obj_size = sizeof(struct ccid3_hc_rx_sock),
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700882 .ccid_hc_rx_init = ccid3_hc_rx_init,
883 .ccid_hc_rx_exit = ccid3_hc_rx_exit,
884 .ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options,
885 .ccid_hc_rx_packet_recv = ccid3_hc_rx_packet_recv,
Arnaldo Carvalho de Melo2babe1f2005-08-23 21:52:35 -0700886 .ccid_hc_rx_get_info = ccid3_hc_rx_get_info,
887 .ccid_hc_tx_get_info = ccid3_hc_tx_get_info,
Arnaldo Carvalho de Melo88f964d2005-09-18 00:19:32 -0700888 .ccid_hc_rx_getsockopt = ccid3_hc_rx_getsockopt,
889 .ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700890};
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200891
Gerrit Renker56724aa2006-11-20 18:28:09 -0200892#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
Gerrit Renker43264992008-08-23 13:28:27 +0200893module_param(ccid3_debug, bool, 0644);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700894MODULE_PARM_DESC(ccid3_debug, "Enable debug messages");
Gerrit Renker56724aa2006-11-20 18:28:09 -0200895#endif
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700896
897static __init int ccid3_module_init(void)
898{
Arnaldo Carvalho de Melo34a9e7e2007-12-06 12:28:13 -0200899 return ccid_register(&ccid3);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700900}
901module_init(ccid3_module_init);
902
903static __exit void ccid3_module_exit(void)
904{
905 ccid_unregister(&ccid3);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700906}
907module_exit(ccid3_module_exit);
908
Ian McDonalde6bccd32006-08-26 19:01:30 -0700909MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>, "
Arnaldo Carvalho de Melo1f2333a2005-08-27 03:51:58 -0300910 "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700911MODULE_DESCRIPTION("DCCP TFRC CCID3 CCID");
912MODULE_LICENSE("GPL");
913MODULE_ALIAS("net-dccp-ccid-3");