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Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -07001/*
Gerrit Renker954c2db2007-12-12 14:06:14 -02002 * Copyright (c) 2007 The University of Aberdeen, Scotland, UK
Ian McDonaldb2f41ff2007-05-28 12:23:29 -03003 * Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
4 * Copyright (c) 2005-7 Ian McDonald <ian.mcdonald@jandi.co.nz>
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -07005 *
6 * An implementation of the DCCP protocol
7 *
8 * This code has been developed by the University of Waikato WAND
9 * research group. For further information please see http://www.wand.net.nz/
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070010 *
11 * This code also uses code from Lulea University, rereleased as GPL by its
12 * authors:
13 * Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
14 *
15 * Changes to meet Linux coding standards, to make it meet latest ccid3 draft
16 * and to make it work as a loadable module in the DCCP stack written by
17 * Arnaldo Carvalho de Melo <acme@conectiva.com.br>.
18 *
19 * Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
20 *
21 * This program is free software; you can redistribute it and/or modify
22 * it under the terms of the GNU General Public License as published by
23 * the Free Software Foundation; either version 2 of the License, or
24 * (at your option) any later version.
25 *
26 * This program is distributed in the hope that it will be useful,
27 * but WITHOUT ANY WARRANTY; without even the implied warranty of
28 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
29 * GNU General Public License for more details.
30 *
31 * You should have received a copy of the GNU General Public License
32 * along with this program; if not, write to the Free Software
33 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
34 */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070035#include "../dccp.h"
36#include "ccid3.h"
37
Gerrit Renker76fd1e82007-10-24 10:46:58 -020038#include <asm/unaligned.h>
39
Gerrit Renker56724aa2006-11-20 18:28:09 -020040#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
41static int ccid3_debug;
42#define ccid3_pr_debug(format, a...) DCCP_PR_DEBUG(ccid3_debug, format, ##a)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070043#else
44#define ccid3_pr_debug(format, a...)
45#endif
46
Gerrit Renker9bf17472007-03-20 13:11:24 -030047/*
48 * Transmitter Half-Connection Routines
49 */
Gerrit Renker410e27a2008-09-09 13:27:22 +020050#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
51static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state)
52{
Jan Engelhardt36cbd3d2009-08-05 10:42:58 -070053 static const char *const ccid3_state_names[] = {
Gerrit Renker410e27a2008-09-09 13:27:22 +020054 [TFRC_SSTATE_NO_SENT] = "NO_SENT",
55 [TFRC_SSTATE_NO_FBACK] = "NO_FBACK",
56 [TFRC_SSTATE_FBACK] = "FBACK",
Gerrit Renker410e27a2008-09-09 13:27:22 +020057 };
58
59 return ccid3_state_names[state];
60}
61#endif
62
63static void ccid3_hc_tx_set_state(struct sock *sk,
64 enum ccid3_hc_tx_states state)
65{
Gerrit Renker996ccf42009-10-05 00:53:13 +000066 struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
67 enum ccid3_hc_tx_states oldstate = hc->tx_state;
Gerrit Renker410e27a2008-09-09 13:27:22 +020068
69 ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
70 dccp_role(sk), sk, ccid3_tx_state_name(oldstate),
71 ccid3_tx_state_name(state));
72 WARN_ON(state == oldstate);
Gerrit Renker996ccf42009-10-05 00:53:13 +000073 hc->tx_state = state;
Gerrit Renker410e27a2008-09-09 13:27:22 +020074}
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070075
Gerrit Renker17893bc2006-11-27 20:31:33 -020076/*
Gerrit Renker6c08b2c2007-11-20 17:33:17 -020077 * Compute the initial sending rate X_init in the manner of RFC 3390:
78 *
Gerrit Renker410e27a2008-09-09 13:27:22 +020079 * X_init = min(4 * s, max(2 * s, 4380 bytes)) / RTT
Gerrit Renker6c08b2c2007-11-20 17:33:17 -020080 *
Gerrit Renker410e27a2008-09-09 13:27:22 +020081 * Note that RFC 3390 uses MSS, RFC 4342 refers to RFC 3390, and rfc3448bis
82 * (rev-02) clarifies the use of RFC 3390 with regard to the above formula.
Gerrit Renkera21f9f92007-03-20 15:12:10 -030083 * For consistency with other parts of the code, X_init is scaled by 2^6.
84 */
85static inline u64 rfc3390_initial_rate(struct sock *sk)
86{
Gerrit Renker996ccf42009-10-05 00:53:13 +000087 const struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
88 const __u32 w_init = clamp_t(__u32, 4380U, 2 * hc->tx_s, 4 * hc->tx_s);
Gerrit Renkera21f9f92007-03-20 15:12:10 -030089
Gerrit Renker996ccf42009-10-05 00:53:13 +000090 return scaled_div(w_init << 6, hc->tx_rtt);
Gerrit Renkera21f9f92007-03-20 15:12:10 -030091}
92
Gerrit Renker20cbd3e2010-09-14 20:16:59 +020093/**
94 * ccid3_update_send_interval - Calculate new t_ipi = s / X_inst
95 * This respects the granularity of X_inst (64 * bytes/second).
Gerrit Renker17893bc2006-11-27 20:31:33 -020096 */
Gerrit Renker996ccf42009-10-05 00:53:13 +000097static void ccid3_update_send_interval(struct ccid3_hc_tx_sock *hc)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070098{
Gerrit Renker996ccf42009-10-05 00:53:13 +000099 hc->tx_t_ipi = scaled_div32(((u64)hc->tx_s) << 6, hc->tx_x);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200100
Gerrit Renker20cbd3e2010-09-14 20:16:59 +0200101 ccid3_pr_debug("t_ipi=%u, s=%u, X=%u\n", hc->tx_t_ipi,
102 hc->tx_s, (unsigned)(hc->tx_x >> 6));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700103}
Gerrit Renkeraa97efd2007-09-25 22:39:16 -0700104
Gerrit Renker996ccf42009-10-05 00:53:13 +0000105static u32 ccid3_hc_tx_idle_rtt(struct ccid3_hc_tx_sock *hc, ktime_t now)
Gerrit Renkera5358fd2007-11-20 18:01:59 -0200106{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000107 u32 delta = ktime_us_delta(now, hc->tx_t_last_win_count);
Gerrit Renkera5358fd2007-11-20 18:01:59 -0200108
Gerrit Renker996ccf42009-10-05 00:53:13 +0000109 return delta / hc->tx_rtt;
Gerrit Renkera5358fd2007-11-20 18:01:59 -0200110}
111
Gerrit Renkeraa97efd2007-09-25 22:39:16 -0700112/**
113 * ccid3_hc_tx_update_x - Update allowed sending rate X
114 * @stamp: most recent time if available - can be left NULL.
115 * This function tracks draft rfc3448bis, check there for latest details.
Gerrit Renker5c3fbb62006-12-03 14:50:56 -0200116 *
Gerrit Renker1a21e492006-12-10 00:02:12 -0200117 * Note: X and X_recv are both stored in units of 64 * bytes/second, to support
118 * fine-grained resolution of sending rates. This requires scaling by 2^6
119 * throughout the code. Only X_calc is unscaled (in bytes/second).
120 *
Gerrit Renker1a21e492006-12-10 00:02:12 -0200121 */
Gerrit Renkeraa97efd2007-09-25 22:39:16 -0700122static void ccid3_hc_tx_update_x(struct sock *sk, ktime_t *stamp)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700123{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000124 struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
125 __u64 min_rate = 2 * hc->tx_x_recv;
126 const __u64 old_x = hc->tx_x;
Gerrit Renker52515e72007-12-17 12:57:43 -0200127 ktime_t now = stamp ? *stamp : ktime_get_real();
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700128
Gerrit Renker0c150ef2007-03-20 15:19:07 -0300129 /*
130 * Handle IDLE periods: do not reduce below RFC3390 initial sending rate
Gerrit Renkera5358fd2007-11-20 18:01:59 -0200131 * when idling [RFC 4342, 5.1]. Definition of idling is from rfc3448bis:
132 * a sender is idle if it has not sent anything over a 2-RTT-period.
Gerrit Renker0c150ef2007-03-20 15:19:07 -0300133 * For consistency with X and X_recv, min_rate is also scaled by 2^6.
134 */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000135 if (ccid3_hc_tx_idle_rtt(hc, now) >= 2) {
Gerrit Renker0c150ef2007-03-20 15:19:07 -0300136 min_rate = rfc3390_initial_rate(sk);
Gerrit Renker996ccf42009-10-05 00:53:13 +0000137 min_rate = max(min_rate, 2 * hc->tx_x_recv);
Gerrit Renker0c150ef2007-03-20 15:19:07 -0300138 }
139
Gerrit Renker996ccf42009-10-05 00:53:13 +0000140 if (hc->tx_p > 0) {
Gerrit Renker1a21e492006-12-10 00:02:12 -0200141
Gerrit Renker996ccf42009-10-05 00:53:13 +0000142 hc->tx_x = min(((__u64)hc->tx_x_calc) << 6, min_rate);
143 hc->tx_x = max(hc->tx_x, (((__u64)hc->tx_s) << 6) / TFRC_T_MBI);
Arnaldo Carvalho de Melob6ee3d42005-08-27 18:18:18 -0300144
Gerrit Renker996ccf42009-10-05 00:53:13 +0000145 } else if (ktime_us_delta(now, hc->tx_t_ld) - (s64)hc->tx_rtt >= 0) {
Gerrit Renker1a21e492006-12-10 00:02:12 -0200146
Gerrit Renker996ccf42009-10-05 00:53:13 +0000147 hc->tx_x = min(2 * hc->tx_x, min_rate);
148 hc->tx_x = max(hc->tx_x,
149 scaled_div(((__u64)hc->tx_s) << 6, hc->tx_rtt));
150 hc->tx_t_ld = now;
Gerrit Renkerff586292006-12-10 00:00:14 -0200151 }
Gerrit Renkera79ef762006-11-28 19:51:42 -0200152
Gerrit Renker996ccf42009-10-05 00:53:13 +0000153 if (hc->tx_x != old_x) {
Gerrit Renker1761f7d2007-03-20 15:04:30 -0300154 ccid3_pr_debug("X_prev=%u, X_now=%u, X_calc=%u, "
155 "X_recv=%u\n", (unsigned)(old_x >> 6),
Gerrit Renker996ccf42009-10-05 00:53:13 +0000156 (unsigned)(hc->tx_x >> 6), hc->tx_x_calc,
157 (unsigned)(hc->tx_x_recv >> 6));
Ian McDonald8699be72007-03-20 14:49:20 -0300158
Gerrit Renker996ccf42009-10-05 00:53:13 +0000159 ccid3_update_send_interval(hc);
Ian McDonald8699be72007-03-20 14:49:20 -0300160 }
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700161}
162
Gerrit Renker78ad7132006-11-28 19:22:33 -0200163/*
Gerrit Renker410e27a2008-09-09 13:27:22 +0200164 * Track the mean packet size `s' (cf. RFC 4342, 5.3 and RFC 3448, 4.1)
165 * @len: DCCP packet payload size in bytes
Gerrit Renker78ad7132006-11-28 19:22:33 -0200166 */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000167static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hc, int len)
Gerrit Renker78ad7132006-11-28 19:22:33 -0200168{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000169 const u16 old_s = hc->tx_s;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200170
Gerrit Renker996ccf42009-10-05 00:53:13 +0000171 hc->tx_s = tfrc_ewma(hc->tx_s, len, 9);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200172
Gerrit Renker996ccf42009-10-05 00:53:13 +0000173 if (hc->tx_s != old_s)
174 ccid3_update_send_interval(hc);
Gerrit Renker78ad7132006-11-28 19:22:33 -0200175}
176
Gerrit Renker9f8681d2006-12-10 00:07:37 -0200177/*
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200178 * Update Window Counter using the algorithm from [RFC 4342, 8.1].
Gerrit Renker825de272008-05-27 06:33:54 -0700179 * As elsewhere, RTT > 0 is assumed by using dccp_sample_rtt().
Gerrit Renker9f8681d2006-12-10 00:07:37 -0200180 */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000181static inline void ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock *hc,
Gerrit Renker8132da42007-06-16 13:34:02 -0300182 ktime_t now)
Gerrit Renker9f8681d2006-12-10 00:07:37 -0200183{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000184 u32 delta = ktime_us_delta(now, hc->tx_t_last_win_count),
185 quarter_rtts = (4 * delta) / hc->tx_rtt;
Gerrit Renker9f8681d2006-12-10 00:07:37 -0200186
187 if (quarter_rtts > 0) {
Gerrit Renker996ccf42009-10-05 00:53:13 +0000188 hc->tx_t_last_win_count = now;
189 hc->tx_last_win_count += min(quarter_rtts, 5U);
190 hc->tx_last_win_count &= 0xF; /* mod 16 */
Gerrit Renker9f8681d2006-12-10 00:07:37 -0200191 }
192}
193
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700194static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
195{
196 struct sock *sk = (struct sock *)data;
Gerrit Renker996ccf42009-10-05 00:53:13 +0000197 struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
Gerrit Renker2a1fda62006-11-28 18:34:34 -0200198 unsigned long t_nfb = USEC_PER_SEC / 5;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700199
200 bh_lock_sock(sk);
201 if (sock_owned_by_user(sk)) {
202 /* Try again later. */
203 /* XXX: set some sensible MIB */
Gerrit Renker48e03ee2006-11-27 20:29:27 -0200204 goto restart_timer;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700205 }
206
Frans Popb1383382010-03-24 07:57:28 +0000207 ccid3_pr_debug("%s(%p, state=%s) - entry\n", dccp_role(sk), sk,
Gerrit Renker996ccf42009-10-05 00:53:13 +0000208 ccid3_tx_state_name(hc->tx_state));
Gerrit Renkera9672412006-12-10 00:14:12 -0200209
Gerrit Renker80763dfb2010-09-19 20:08:24 +0200210 /* Ignore and do not restart after leaving the established state */
211 if ((1 << sk->sk_state) & ~(DCCPF_OPEN | DCCPF_PARTOPEN))
212 goto out;
213
214 /* Reset feedback state to "no feedback received" */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000215 if (hc->tx_state == TFRC_SSTATE_FBACK)
Gerrit Renker410e27a2008-09-09 13:27:22 +0200216 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
Gerrit Renkerd0995e62008-09-04 07:30:19 +0200217
Gerrit Renker52515e72007-12-17 12:57:43 -0200218 /*
219 * Determine new allowed sending rate X as per draft rfc3448bis-00, 4.4
Gerrit Renker67b67e32010-08-22 19:41:36 +0000220 * RTO is 0 if and only if no feedback has been received yet.
Gerrit Renker52515e72007-12-17 12:57:43 -0200221 */
Gerrit Renker67b67e32010-08-22 19:41:36 +0000222 if (hc->tx_t_rto == 0 || hc->tx_p == 0) {
Gerrit Renker52515e72007-12-17 12:57:43 -0200223
224 /* halve send rate directly */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000225 hc->tx_x = max(hc->tx_x / 2,
226 (((__u64)hc->tx_s) << 6) / TFRC_T_MBI);
227 ccid3_update_send_interval(hc);
Gerrit Renker52515e72007-12-17 12:57:43 -0200228 } else {
Arnaldo Carvalho de Melo1f2333a2005-08-27 03:51:58 -0300229 /*
Gerrit Renker52515e72007-12-17 12:57:43 -0200230 * Modify the cached value of X_recv
Gerrit Renker0c150ef2007-03-20 15:19:07 -0300231 *
Gerrit Renker52515e72007-12-17 12:57:43 -0200232 * If (X_calc > 2 * X_recv)
Gerrit Renker0c150ef2007-03-20 15:19:07 -0300233 * X_recv = max(X_recv / 2, s / (2 * t_mbi));
234 * Else
235 * X_recv = X_calc / 4;
236 *
237 * Note that X_recv is scaled by 2^6 while X_calc is not
Arnaldo Carvalho de Melo1f2333a2005-08-27 03:51:58 -0300238 */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000239 BUG_ON(hc->tx_p && !hc->tx_x_calc);
Gerrit Renkera79ef762006-11-28 19:51:42 -0200240
Gerrit Renker996ccf42009-10-05 00:53:13 +0000241 if (hc->tx_x_calc > (hc->tx_x_recv >> 5))
242 hc->tx_x_recv =
243 max(hc->tx_x_recv / 2,
244 (((__u64)hc->tx_s) << 6) / (2*TFRC_T_MBI));
Gerrit Renker52515e72007-12-17 12:57:43 -0200245 else {
Gerrit Renker996ccf42009-10-05 00:53:13 +0000246 hc->tx_x_recv = hc->tx_x_calc;
247 hc->tx_x_recv <<= 4;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700248 }
Gerrit Renkeraa97efd2007-09-25 22:39:16 -0700249 ccid3_hc_tx_update_x(sk, NULL);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700250 }
Gerrit Renker52515e72007-12-17 12:57:43 -0200251 ccid3_pr_debug("Reduced X to %llu/64 bytes/sec\n",
Gerrit Renker996ccf42009-10-05 00:53:13 +0000252 (unsigned long long)hc->tx_x);
Gerrit Renker52515e72007-12-17 12:57:43 -0200253
254 /*
255 * Set new timeout for the nofeedback timer.
256 * See comments in packet_recv() regarding the value of t_RTO.
257 */
Gerrit Renker67b67e32010-08-22 19:41:36 +0000258 if (unlikely(hc->tx_t_rto == 0)) /* no feedback received yet */
Gerrit Renker52515e72007-12-17 12:57:43 -0200259 t_nfb = TFRC_INITIAL_TIMEOUT;
260 else
Gerrit Renker996ccf42009-10-05 00:53:13 +0000261 t_nfb = max(hc->tx_t_rto, 2 * hc->tx_t_ipi);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700262
Gerrit Renker48e03ee2006-11-27 20:29:27 -0200263restart_timer:
Gerrit Renker996ccf42009-10-05 00:53:13 +0000264 sk_reset_timer(sk, &hc->tx_no_feedback_timer,
YOSHIFUJI Hideakic9eaf172007-02-09 23:24:38 +0900265 jiffies + usecs_to_jiffies(t_nfb));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700266out:
267 bh_unlock_sock(sk);
268 sock_put(sk);
269}
270
Gerrit Renkerfe84f412010-10-27 19:16:25 +0000271/**
272 * ccid3_hc_tx_send_packet - Delay-based dequeueing of TX packets
273 * @skb: next packet candidate to send on @sk
274 * This function uses the convention of ccid_packet_dequeue_eval() and
275 * returns a millisecond-delay value between 0 and t_mbi = 64000 msec.
Gerrit Renker7da7f452006-11-27 12:26:03 -0200276 */
Gerrit Renker6b57c932006-11-28 19:55:06 -0200277static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700278{
279 struct dccp_sock *dp = dccp_sk(sk);
Gerrit Renker996ccf42009-10-05 00:53:13 +0000280 struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
Gerrit Renker8132da42007-06-16 13:34:02 -0300281 ktime_t now = ktime_get_real();
282 s64 delay;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700283
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700284 /*
Gerrit Renkerda335ba2006-11-27 12:26:57 -0200285 * This function is called only for Data and DataAck packets. Sending
286 * zero-sized Data(Ack)s is theoretically possible, but for congestion
287 * control this case is pathological - ignore it.
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700288 */
Gerrit Renker6b57c932006-11-28 19:55:06 -0200289 if (unlikely(skb->len == 0))
Gerrit Renkerda335ba2006-11-27 12:26:57 -0200290 return -EBADMSG;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700291
Gerrit Renker80763dfb2010-09-19 20:08:24 +0200292 if (hc->tx_state == TFRC_SSTATE_NO_SENT) {
Gerrit Renker996ccf42009-10-05 00:53:13 +0000293 sk_reset_timer(sk, &hc->tx_no_feedback_timer, (jiffies +
294 usecs_to_jiffies(TFRC_INITIAL_TIMEOUT)));
295 hc->tx_last_win_count = 0;
296 hc->tx_t_last_win_count = now;
Gerrit Renker90feeb92006-11-27 12:13:38 -0200297
298 /* Set t_0 for initial packet */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000299 hc->tx_t_nom = now;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200300
Gerrit Renker996ccf42009-10-05 00:53:13 +0000301 hc->tx_s = skb->len;
Gerrit Renker30833ff2007-03-20 15:31:56 -0300302
Gerrit Renker30833ff2007-03-20 15:31:56 -0300303 /*
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 Renker996ccf42009-10-05 00:53:13 +0000310 hc->tx_rtt = dp->dccps_syn_rtt;
311 hc->tx_x = rfc3390_initial_rate(sk);
312 hc->tx_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 Renker996ccf42009-10-05 00:53:13 +0000320 hc->tx_rtt = DCCP_FALLBACK_RTT;
321 hc->tx_x = hc->tx_s;
322 hc->tx_x <<= 6;
Gerrit Renker30833ff2007-03-20 15:31:56 -0300323 }
Gerrit Renker996ccf42009-10-05 00:53:13 +0000324 ccid3_update_send_interval(hc);
Gerrit Renker30833ff2007-03-20 15:31:56 -0300325
Gerrit Renker410e27a2008-09-09 13:27:22 +0200326 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
Gerrit Renker80763dfb2010-09-19 20:08:24 +0200327
328 } else {
Gerrit Renker996ccf42009-10-05 00:53:13 +0000329 delay = ktime_us_delta(hc->tx_t_nom, now);
Ian McDonald8699be72007-03-20 14:49:20 -0300330 ccid3_pr_debug("delay=%ld\n", (long)delay);
Gerrit Renker91cf5a12006-11-27 12:25:10 -0200331 /*
Gerrit Renker20cbd3e2010-09-14 20:16:59 +0200332 * Scheduling of packet transmissions (RFC 5348, 8.3)
Gerrit Renker91cf5a12006-11-27 12:25:10 -0200333 *
334 * if (t_now > t_nom - delta)
335 * // send the packet now
336 * else
337 * // send the packet in (t_nom - t_now) milliseconds.
338 */
Gerrit Renker20cbd3e2010-09-14 20:16:59 +0200339 if (delay >= TFRC_T_DELTA)
340 return (u32)delay / USEC_PER_MSEC;
Gerrit Renker9f8681d2006-12-10 00:07:37 -0200341
Gerrit Renker996ccf42009-10-05 00:53:13 +0000342 ccid3_hc_tx_update_win_count(hc, now);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700343 }
344
Gerrit Renker7da7f452006-11-27 12:26:03 -0200345 /* prepare to send now (add options etc.) */
346 dp->dccps_hc_tx_insert_options = 1;
Gerrit Renker996ccf42009-10-05 00:53:13 +0000347 DCCP_SKB_CB(skb)->dccpd_ccval = hc->tx_last_win_count;
Gerrit Renkere312d102006-12-10 00:08:09 -0200348
349 /* set the nominal send time for the next following packet */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000350 hc->tx_t_nom = ktime_add_us(hc->tx_t_nom, hc->tx_t_ipi);
Gerrit Renkerfe84f412010-10-27 19:16:25 +0000351 return CCID_PACKET_SEND_AT_ONCE;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700352}
353
Gerrit Renkerbaf9e782010-10-11 20:37:38 +0200354static void ccid3_hc_tx_packet_sent(struct sock *sk, unsigned int len)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700355{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000356 struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700357
Gerrit Renker996ccf42009-10-05 00:53:13 +0000358 ccid3_hc_tx_update_s(hc, len);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700359
Gerrit Renker996ccf42009-10-05 00:53:13 +0000360 if (tfrc_tx_hist_add(&hc->tx_hist, dccp_sk(sk)->dccps_gss))
Gerrit Renkerc5a1ae92006-12-10 00:09:21 -0200361 DCCP_CRIT("packet history - out of memory!");
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700362}
363
364static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
365{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000366 struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
Gerrit Renkerd2c72632010-09-14 20:18:00 +0200367 struct tfrc_tx_hist_entry *acked;
Arnaldo Carvalho de Melo0740d492007-08-19 17:18:13 -0700368 ktime_t now;
Gerrit Renker2a1fda62006-11-28 18:34:34 -0200369 unsigned long t_nfb;
Gerrit Renker536bb202010-09-19 20:14:23 +0200370 u32 r_sample;
Arnaldo Carvalho de Melo1f2333a2005-08-27 03:51:58 -0300371
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700372 /* we are only interested in ACKs */
373 if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
374 DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
375 return;
Gerrit Renkerd2c72632010-09-14 20:18:00 +0200376 /*
377 * Locate the acknowledged packet in the TX history.
378 *
379 * Returning "entry not found" here can for instance happen when
380 * - the host has not sent out anything (e.g. a passive server),
381 * - the Ack is outdated (packet with higher Ack number was received),
382 * - it is a bogus Ack (for a packet not sent on this connection).
383 */
384 acked = tfrc_tx_hist_find_entry(hc->tx_hist, dccp_hdr_ack_seq(skb));
385 if (acked == NULL)
Gerrit Renker410e27a2008-09-09 13:27:22 +0200386 return;
Gerrit Renkerd2c72632010-09-14 20:18:00 +0200387 /* For the sake of RTT sampling, ignore/remove all older entries */
388 tfrc_tx_hist_purge(&acked->next);
389
390 /* Update the moving average for the RTT estimate (RFC 3448, 4.3) */
391 now = ktime_get_real();
392 r_sample = dccp_sample_rtt(sk, ktime_us_delta(now, acked->stamp));
393 hc->tx_rtt = tfrc_ewma(hc->tx_rtt, r_sample, 9);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200394
Gerrit Renkerd8d12522007-12-17 12:48:47 -0200395 /*
396 * Update allowed sending rate X as per draft rfc3448bis-00, 4.2/3
397 */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000398 if (hc->tx_state == TFRC_SSTATE_NO_FBACK) {
Gerrit Renker410e27a2008-09-09 13:27:22 +0200399 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200400
Gerrit Renker996ccf42009-10-05 00:53:13 +0000401 if (hc->tx_t_rto == 0) {
Gerrit Renkerd8d12522007-12-17 12:48:47 -0200402 /*
403 * Initial feedback packet: Larger Initial Windows (4.2)
404 */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000405 hc->tx_x = rfc3390_initial_rate(sk);
406 hc->tx_t_ld = now;
Gerrit Renkerd8d12522007-12-17 12:48:47 -0200407
Gerrit Renker996ccf42009-10-05 00:53:13 +0000408 ccid3_update_send_interval(hc);
Gerrit Renkerd8d12522007-12-17 12:48:47 -0200409
410 goto done_computing_x;
Gerrit Renker996ccf42009-10-05 00:53:13 +0000411 } else if (hc->tx_p == 0) {
Gerrit Renkerd8d12522007-12-17 12:48:47 -0200412 /*
413 * First feedback after nofeedback timer expiry (4.3)
414 */
415 goto done_computing_x;
416 }
417 }
418
419 /* Update sending rate (step 4 of [RFC 3448, 4.3]) */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000420 if (hc->tx_p > 0)
421 hc->tx_x_calc = tfrc_calc_x(hc->tx_s, hc->tx_rtt, hc->tx_p);
Gerrit Renkerd8d12522007-12-17 12:48:47 -0200422 ccid3_hc_tx_update_x(sk, &now);
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200423
Gerrit Renkerd8d12522007-12-17 12:48:47 -0200424done_computing_x:
425 ccid3_pr_debug("%s(%p), RTT=%uus (sample=%uus), s=%u, "
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200426 "p=%u, X_calc=%u, X_recv=%u, X=%u\n",
Gerrit Renker996ccf42009-10-05 00:53:13 +0000427 dccp_role(sk), sk, hc->tx_rtt, r_sample,
428 hc->tx_s, hc->tx_p, hc->tx_x_calc,
429 (unsigned)(hc->tx_x_recv >> 6),
430 (unsigned)(hc->tx_x >> 6));
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200431
432 /* unschedule no feedback timer */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000433 sk_stop_timer(sk, &hc->tx_no_feedback_timer);
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200434
435 /*
436 * As we have calculated new ipi, delta, t_nom it is possible
437 * that we now can send a packet, so wake up dccp_wait_for_ccid
438 */
439 sk->sk_write_space(sk);
440
441 /*
Gerrit Renker89858ad2010-08-29 19:23:14 +0000442 * Update timeout interval for the nofeedback timer. In order to control
443 * rate halving on networks with very low RTTs (<= 1 ms), use per-route
444 * tunable RTAX_RTO_MIN value as the lower bound.
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200445 */
Gerrit Renker89858ad2010-08-29 19:23:14 +0000446 hc->tx_t_rto = max_t(u32, 4 * hc->tx_rtt,
447 USEC_PER_SEC/HZ * tcp_rto_min(sk));
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200448 /*
449 * Schedule no feedback timer to expire in
450 * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
451 */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000452 t_nfb = max(hc->tx_t_rto, 2 * hc->tx_t_ipi);
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200453
454 ccid3_pr_debug("%s(%p), Scheduled no feedback timer to "
455 "expire in %lu jiffies (%luus)\n",
Gerrit Renker388d5e92009-10-05 00:53:11 +0000456 dccp_role(sk), sk, usecs_to_jiffies(t_nfb), t_nfb);
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200457
Gerrit Renker996ccf42009-10-05 00:53:13 +0000458 sk_reset_timer(sk, &hc->tx_no_feedback_timer,
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200459 jiffies + usecs_to_jiffies(t_nfb));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700460}
461
Gerrit Renker4874c132010-09-19 20:06:50 +0200462static int ccid3_hc_tx_parse_options(struct sock *sk, u8 packet_type,
463 u8 option, u8 *optval, u8 optlen)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700464{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000465 struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
Gerrit Renker76fd1e82007-10-24 10:46:58 -0200466 __be32 opt_val;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700467
Gerrit Renker410e27a2008-09-09 13:27:22 +0200468 switch (option) {
Gerrit Renker37efb032010-09-14 20:21:29 +0200469 case TFRC_OPT_RECEIVE_RATE:
Gerrit Renker410e27a2008-09-09 13:27:22 +0200470 case TFRC_OPT_LOSS_EVENT_RATE:
Gerrit Renker4874c132010-09-19 20:06:50 +0200471 /* Must be ignored on Data packets, cf. RFC 4342 8.3 and 8.5 */
472 if (packet_type == DCCP_PKT_DATA)
473 break;
474 if (unlikely(optlen != 4)) {
Gerrit Renker37efb032010-09-14 20:21:29 +0200475 DCCP_WARN("%s(%p), invalid len %d for %u\n",
Gerrit Renker4874c132010-09-19 20:06:50 +0200476 dccp_role(sk), sk, optlen, option);
Gerrit Renker37efb032010-09-14 20:21:29 +0200477 return -EINVAL;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200478 }
Gerrit Renker4874c132010-09-19 20:06:50 +0200479 opt_val = ntohl(get_unaligned((__be32 *)optval));
Gerrit Renker410e27a2008-09-09 13:27:22 +0200480
Gerrit Renker37efb032010-09-14 20:21:29 +0200481 if (option == TFRC_OPT_RECEIVE_RATE) {
Gerrit Renker536bb202010-09-19 20:14:23 +0200482 /* Receive Rate is kept in units of 64 bytes/second */
483 hc->tx_x_recv = opt_val;
484 hc->tx_x_recv <<= 6;
485
Gerrit Renker37efb032010-09-14 20:21:29 +0200486 ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n",
487 dccp_role(sk), sk, opt_val);
488 } else {
Gerrit Renker536bb202010-09-19 20:14:23 +0200489 /* Update the fixpoint Loss Event Rate fraction */
490 hc->tx_p = tfrc_invert_loss_event_rate(opt_val);
491
Gerrit Renker37efb032010-09-14 20:21:29 +0200492 ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n",
493 dccp_role(sk), sk, opt_val);
494 }
495 }
496 return 0;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700497}
498
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800499static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700500{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000501 struct ccid3_hc_tx_sock *hc = ccid_priv(ccid);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700502
Gerrit Renker996ccf42009-10-05 00:53:13 +0000503 hc->tx_state = TFRC_SSTATE_NO_SENT;
504 hc->tx_hist = NULL;
505 setup_timer(&hc->tx_no_feedback_timer,
Gerrit Renker410e27a2008-09-09 13:27:22 +0200506 ccid3_hc_tx_no_feedback_timer, (unsigned long)sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700507 return 0;
508}
509
510static void ccid3_hc_tx_exit(struct sock *sk)
511{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000512 struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700513
Gerrit Renker996ccf42009-10-05 00:53:13 +0000514 sk_stop_timer(sk, &hc->tx_no_feedback_timer);
Gerrit Renker996ccf42009-10-05 00:53:13 +0000515 tfrc_tx_hist_purge(&hc->tx_hist);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700516}
517
Gerrit Renker9bf17472007-03-20 13:11:24 -0300518static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info)
519{
Gerrit Renker51c22bb2010-08-22 19:41:37 +0000520 info->tcpi_rto = ccid3_hc_tx_sk(sk)->tx_t_rto;
521 info->tcpi_rtt = ccid3_hc_tx_sk(sk)->tx_rtt;
Gerrit Renker9bf17472007-03-20 13:11:24 -0300522}
523
524static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
525 u32 __user *optval, int __user *optlen)
526{
Gerrit Renker51c22bb2010-08-22 19:41:37 +0000527 const struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
Gerrit Renker67b67e32010-08-22 19:41:36 +0000528 struct tfrc_tx_info tfrc;
Gerrit Renker9bf17472007-03-20 13:11:24 -0300529 const void *val;
530
Gerrit Renker9bf17472007-03-20 13:11:24 -0300531 switch (optname) {
532 case DCCP_SOCKOPT_CCID_TX_INFO:
Gerrit Renker67b67e32010-08-22 19:41:36 +0000533 if (len < sizeof(tfrc))
Gerrit Renker9bf17472007-03-20 13:11:24 -0300534 return -EINVAL;
Gerrit Renker67b67e32010-08-22 19:41:36 +0000535 tfrc.tfrctx_x = hc->tx_x;
536 tfrc.tfrctx_x_recv = hc->tx_x_recv;
537 tfrc.tfrctx_x_calc = hc->tx_x_calc;
538 tfrc.tfrctx_rtt = hc->tx_rtt;
539 tfrc.tfrctx_p = hc->tx_p;
540 tfrc.tfrctx_rto = hc->tx_t_rto;
541 tfrc.tfrctx_ipi = hc->tx_t_ipi;
542 len = sizeof(tfrc);
543 val = &tfrc;
Gerrit Renker9bf17472007-03-20 13:11:24 -0300544 break;
545 default:
546 return -ENOPROTOOPT;
547 }
548
549 if (put_user(len, optlen) || copy_to_user(optval, val, len))
550 return -EFAULT;
551
552 return 0;
553}
554
555/*
556 * Receiver Half-Connection Routines
557 */
Gerrit Renker410e27a2008-09-09 13:27:22 +0200558
559/* CCID3 feedback types */
560enum ccid3_fback_type {
561 CCID3_FBACK_NONE = 0,
562 CCID3_FBACK_INITIAL,
563 CCID3_FBACK_PERIODIC,
564 CCID3_FBACK_PARAM_CHANGE
565};
566
567#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
568static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
569{
Jan Engelhardt36cbd3d2009-08-05 10:42:58 -0700570 static const char *const ccid3_rx_state_names[] = {
Gerrit Renker410e27a2008-09-09 13:27:22 +0200571 [TFRC_RSTATE_NO_DATA] = "NO_DATA",
572 [TFRC_RSTATE_DATA] = "DATA",
Gerrit Renker410e27a2008-09-09 13:27:22 +0200573 };
574
575 return ccid3_rx_state_names[state];
576}
577#endif
578
579static void ccid3_hc_rx_set_state(struct sock *sk,
580 enum ccid3_hc_rx_states state)
581{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000582 struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
583 enum ccid3_hc_rx_states oldstate = hc->rx_state;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200584
585 ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
586 dccp_role(sk), sk, ccid3_rx_state_name(oldstate),
587 ccid3_rx_state_name(state));
588 WARN_ON(state == oldstate);
Gerrit Renker996ccf42009-10-05 00:53:13 +0000589 hc->rx_state = state;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200590}
591
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200592static void ccid3_hc_rx_send_feedback(struct sock *sk,
593 const struct sk_buff *skb,
594 enum ccid3_fback_type fbtype)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700595{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000596 struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200597 struct dccp_sock *dp = dccp_sk(sk);
Gerrit Renker80763dfb2010-09-19 20:08:24 +0200598 ktime_t now = ktime_get_real();
Gerrit Renker410e27a2008-09-09 13:27:22 +0200599 s64 delta = 0;
600
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200601 switch (fbtype) {
602 case CCID3_FBACK_INITIAL:
Gerrit Renker996ccf42009-10-05 00:53:13 +0000603 hc->rx_x_recv = 0;
604 hc->rx_pinv = ~0U; /* see RFC 4342, 8.5 */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700605 break;
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200606 case CCID3_FBACK_PARAM_CHANGE:
607 /*
608 * When parameters change (new loss or p > p_prev), we do not
609 * have a reliable estimate for R_m of [RFC 3448, 6.2] and so
Gerrit Renker410e27a2008-09-09 13:27:22 +0200610 * need to reuse the previous value of X_recv. However, when
611 * X_recv was 0 (due to early loss), this would kill X down to
612 * s/t_mbi (i.e. one packet in 64 seconds).
613 * To avoid such drastic reduction, we approximate X_recv as
614 * the number of bytes since last feedback.
615 * This is a safe fallback, since X is bounded above by X_calc.
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200616 */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000617 if (hc->rx_x_recv > 0)
Gerrit Renker410e27a2008-09-09 13:27:22 +0200618 break;
619 /* fall through */
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200620 case CCID3_FBACK_PERIODIC:
Gerrit Renker996ccf42009-10-05 00:53:13 +0000621 delta = ktime_us_delta(now, hc->rx_tstamp_last_feedback);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200622 if (delta <= 0)
623 DCCP_BUG("delta (%ld) <= 0", (long)delta);
624 else
Gerrit Renker996ccf42009-10-05 00:53:13 +0000625 hc->rx_x_recv = scaled_div32(hc->rx_bytes_recv, delta);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700626 break;
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200627 default:
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700628 return;
629 }
630
Gerrit Renker410e27a2008-09-09 13:27:22 +0200631 ccid3_pr_debug("Interval %ldusec, X_recv=%u, 1/p=%u\n", (long)delta,
Gerrit Renker996ccf42009-10-05 00:53:13 +0000632 hc->rx_x_recv, hc->rx_pinv);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700633
Gerrit Renker996ccf42009-10-05 00:53:13 +0000634 hc->rx_tstamp_last_feedback = now;
635 hc->rx_last_counter = dccp_hdr(skb)->dccph_ccval;
636 hc->rx_bytes_recv = 0;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200637
638 dp->dccps_hc_rx_insert_options = 1;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700639 dccp_send_ack(sk);
640}
641
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -0800642static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700643{
Gerrit Renker51c22bb2010-08-22 19:41:37 +0000644 const struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
Andrea Bittau60fe62e2006-03-20 19:23:32 -0800645 __be32 x_recv, pinv;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700646
Arnaldo Carvalho de Melo59d203f2005-09-09 20:01:25 -0300647 if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -0800648 return 0;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700649
Arnaldo Carvalho de Melo4fded332005-08-23 21:51:59 -0700650 if (dccp_packet_without_ack(skb))
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -0800651 return 0;
652
Gerrit Renker996ccf42009-10-05 00:53:13 +0000653 x_recv = htonl(hc->rx_x_recv);
654 pinv = htonl(hc->rx_pinv);
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -0800655
Gerrit Renkera7d13fb2010-06-22 01:14:34 +0000656 if (dccp_insert_option(skb, TFRC_OPT_LOSS_EVENT_RATE,
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200657 &pinv, sizeof(pinv)) ||
Gerrit Renkera7d13fb2010-06-22 01:14:34 +0000658 dccp_insert_option(skb, TFRC_OPT_RECEIVE_RATE,
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200659 &x_recv, sizeof(x_recv)))
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -0800660 return -1;
661
662 return 0;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700663}
664
Gerrit Renkeraa1b1ff2009-09-12 07:47:01 +0000665/**
666 * ccid3_first_li - Implements [RFC 5348, 6.3.1]
Gerrit Renker954c2db2007-12-12 14:06:14 -0200667 *
668 * Determine the length of the first loss interval via inverse lookup.
669 * Assume that X_recv can be computed by the throughput equation
670 * s
671 * X_recv = --------
672 * R * fval
673 * Find some p such that f(p) = fval; return 1/p (scaled).
674 */
675static u32 ccid3_first_li(struct sock *sk)
676{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000677 struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200678 u32 x_recv, p, delta;
Gerrit Renker954c2db2007-12-12 14:06:14 -0200679 u64 fval;
680
Gerrit Renker996ccf42009-10-05 00:53:13 +0000681 if (hc->rx_rtt == 0) {
Gerrit Renker410e27a2008-09-09 13:27:22 +0200682 DCCP_WARN("No RTT estimate available, using fallback RTT\n");
Gerrit Renker996ccf42009-10-05 00:53:13 +0000683 hc->rx_rtt = DCCP_FALLBACK_RTT;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200684 }
Gerrit Renkerd20ed952008-09-04 07:30:19 +0200685
Gerrit Renker996ccf42009-10-05 00:53:13 +0000686 delta = ktime_to_us(net_timedelta(hc->rx_tstamp_last_feedback));
687 x_recv = scaled_div32(hc->rx_bytes_recv, delta);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200688 if (x_recv == 0) { /* would also trigger divide-by-zero */
689 DCCP_WARN("X_recv==0\n");
Gerrit Renker67b67e32010-08-22 19:41:36 +0000690 if (hc->rx_x_recv == 0) {
Gerrit Renker410e27a2008-09-09 13:27:22 +0200691 DCCP_BUG("stored value of X_recv is zero");
692 return ~0U;
693 }
Gerrit Renker67b67e32010-08-22 19:41:36 +0000694 x_recv = hc->rx_x_recv;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200695 }
Gerrit Renker954c2db2007-12-12 14:06:14 -0200696
Gerrit Renker996ccf42009-10-05 00:53:13 +0000697 fval = scaled_div(hc->rx_s, hc->rx_rtt);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200698 fval = scaled_div32(fval, x_recv);
Gerrit Renker954c2db2007-12-12 14:06:14 -0200699 p = tfrc_calc_x_reverse_lookup(fval);
700
701 ccid3_pr_debug("%s(%p), receive rate=%u bytes/s, implied "
702 "loss rate=%u\n", dccp_role(sk), sk, x_recv, p);
703
Gerrit Renker410e27a2008-09-09 13:27:22 +0200704 return p == 0 ? ~0U : scaled_div(1, p);
Gerrit Renker954c2db2007-12-12 14:06:14 -0200705}
706
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700707static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
708{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000709 struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200710 enum ccid3_fback_type do_feedback = CCID3_FBACK_NONE;
Gerrit Renker5b5d0e72008-07-13 11:51:40 +0100711 const u64 ndp = dccp_sk(sk)->dccps_options_received.dccpor_ndp;
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200712 const bool is_data_packet = dccp_data_packet(skb);
Arnaldo Carvalho de Melo1f2333a2005-08-27 03:51:58 -0300713
Gerrit Renker996ccf42009-10-05 00:53:13 +0000714 if (unlikely(hc->rx_state == TFRC_RSTATE_NO_DATA)) {
Gerrit Renker410e27a2008-09-09 13:27:22 +0200715 if (is_data_packet) {
716 const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4;
717 do_feedback = CCID3_FBACK_INITIAL;
718 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA);
Gerrit Renker996ccf42009-10-05 00:53:13 +0000719 hc->rx_s = payload;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200720 /*
Gerrit Renker388d5e92009-10-05 00:53:11 +0000721 * Not necessary to update rx_bytes_recv here,
Gerrit Renker410e27a2008-09-09 13:27:22 +0200722 * since X_recv = 0 for the first feedback packet (cf.
723 * RFC 3448, 6.3) -- gerrit
724 */
725 }
726 goto update_records;
727 }
728
Gerrit Renker996ccf42009-10-05 00:53:13 +0000729 if (tfrc_rx_hist_duplicate(&hc->rx_hist, skb))
Gerrit Renker410e27a2008-09-09 13:27:22 +0200730 return; /* done receiving */
731
732 if (is_data_packet) {
733 const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4;
734 /*
735 * Update moving-average of s and the sum of received payload bytes
736 */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000737 hc->rx_s = tfrc_ewma(hc->rx_s, payload, 9);
738 hc->rx_bytes_recv += payload;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200739 }
740
Gerrit Renkerd20ed952008-09-04 07:30:19 +0200741 /*
742 * Perform loss detection and handle pending losses
743 */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000744 if (tfrc_rx_handle_loss(&hc->rx_hist, &hc->rx_li_hist,
Gerrit Renker410e27a2008-09-09 13:27:22 +0200745 skb, ndp, ccid3_first_li, sk)) {
746 do_feedback = CCID3_FBACK_PARAM_CHANGE;
747 goto done_receiving;
748 }
749
Gerrit Renker996ccf42009-10-05 00:53:13 +0000750 if (tfrc_rx_hist_loss_pending(&hc->rx_hist))
Gerrit Renker410e27a2008-09-09 13:27:22 +0200751 return; /* done receiving */
752
Gerrit Renker88e97a92008-09-04 07:30:19 +0200753 /*
Gerrit Renker410e27a2008-09-09 13:27:22 +0200754 * Handle data packets: RTT sampling and monitoring p
Gerrit Renker88e97a92008-09-04 07:30:19 +0200755 */
Gerrit Renker410e27a2008-09-09 13:27:22 +0200756 if (unlikely(!is_data_packet))
757 goto update_records;
758
Gerrit Renker996ccf42009-10-05 00:53:13 +0000759 if (!tfrc_lh_is_initialised(&hc->rx_li_hist)) {
760 const u32 sample = tfrc_rx_hist_sample_rtt(&hc->rx_hist, skb);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200761 /*
762 * Empty loss history: no loss so far, hence p stays 0.
763 * Sample RTT values, since an RTT estimate is required for the
764 * computation of p when the first loss occurs; RFC 3448, 6.3.1.
765 */
766 if (sample != 0)
Gerrit Renker996ccf42009-10-05 00:53:13 +0000767 hc->rx_rtt = tfrc_ewma(hc->rx_rtt, sample, 9);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200768
Gerrit Renker996ccf42009-10-05 00:53:13 +0000769 } else if (tfrc_lh_update_i_mean(&hc->rx_li_hist, skb)) {
Gerrit Renker410e27a2008-09-09 13:27:22 +0200770 /*
771 * Step (3) of [RFC 3448, 6.1]: Recompute I_mean and, if I_mean
772 * has decreased (resp. p has increased), send feedback now.
773 */
774 do_feedback = CCID3_FBACK_PARAM_CHANGE;
775 }
776
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200777 /*
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200778 * Check if the periodic once-per-RTT feedback is due; RFC 4342, 10.3
779 */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000780 if (SUB16(dccp_hdr(skb)->dccph_ccval, hc->rx_last_counter) > 3)
Gerrit Renker410e27a2008-09-09 13:27:22 +0200781 do_feedback = CCID3_FBACK_PERIODIC;
782
783update_records:
Gerrit Renker996ccf42009-10-05 00:53:13 +0000784 tfrc_rx_hist_add_packet(&hc->rx_hist, skb, ndp);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200785
786done_receiving:
787 if (do_feedback)
788 ccid3_hc_rx_send_feedback(sk, skb, do_feedback);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700789}
790
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800791static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700792{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000793 struct ccid3_hc_rx_sock *hc = ccid_priv(ccid);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700794
Gerrit Renker996ccf42009-10-05 00:53:13 +0000795 hc->rx_state = TFRC_RSTATE_NO_DATA;
796 tfrc_lh_init(&hc->rx_li_hist);
797 return tfrc_rx_hist_alloc(&hc->rx_hist);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700798}
799
800static void ccid3_hc_rx_exit(struct sock *sk)
801{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000802 struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700803
Gerrit Renker996ccf42009-10-05 00:53:13 +0000804 tfrc_rx_hist_purge(&hc->rx_hist);
805 tfrc_lh_cleanup(&hc->rx_li_hist);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700806}
807
Arnaldo Carvalho de Melo2babe1f2005-08-23 21:52:35 -0700808static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
809{
Gerrit Renker51c22bb2010-08-22 19:41:37 +0000810 info->tcpi_ca_state = ccid3_hc_rx_sk(sk)->rx_state;
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200811 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
Gerrit Renker51c22bb2010-08-22 19:41:37 +0000812 info->tcpi_rcv_rtt = ccid3_hc_rx_sk(sk)->rx_rtt;
Arnaldo Carvalho de Melo2babe1f2005-08-23 21:52:35 -0700813}
814
Arnaldo Carvalho de Melo88f964d2005-09-18 00:19:32 -0700815static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len,
816 u32 __user *optval, int __user *optlen)
817{
Gerrit Renker51c22bb2010-08-22 19:41:37 +0000818 const struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
Gerrit Renker8e138e72007-12-17 10:07:44 -0200819 struct tfrc_rx_info rx_info;
Arnaldo Carvalho de Melo88f964d2005-09-18 00:19:32 -0700820 const void *val;
YOSHIFUJI Hideakic9eaf172007-02-09 23:24:38 +0900821
Arnaldo Carvalho de Melo88f964d2005-09-18 00:19:32 -0700822 switch (optname) {
823 case DCCP_SOCKOPT_CCID_RX_INFO:
Gerrit Renker8e138e72007-12-17 10:07:44 -0200824 if (len < sizeof(rx_info))
Arnaldo Carvalho de Melo88f964d2005-09-18 00:19:32 -0700825 return -EINVAL;
Gerrit Renker996ccf42009-10-05 00:53:13 +0000826 rx_info.tfrcrx_x_recv = hc->rx_x_recv;
827 rx_info.tfrcrx_rtt = hc->rx_rtt;
Gerrit Renker792e6d32010-09-19 20:10:52 +0200828 rx_info.tfrcrx_p = tfrc_invert_loss_event_rate(hc->rx_pinv);
Gerrit Renker8e138e72007-12-17 10:07:44 -0200829 len = sizeof(rx_info);
830 val = &rx_info;
Arnaldo Carvalho de Melo88f964d2005-09-18 00:19:32 -0700831 break;
832 default:
833 return -ENOPROTOOPT;
834 }
835
836 if (put_user(len, optlen) || copy_to_user(optval, val, len))
837 return -EFAULT;
838
839 return 0;
840}
841
Gerrit Renkerddebc972009-01-04 21:42:53 -0800842struct ccid_operations ccid3_ops = {
Ian McDonald3dd9a7c2006-09-22 14:26:44 +1200843 .ccid_id = DCCPC_CCID3,
Gerrit Renker84a97b02007-12-13 23:33:25 -0200844 .ccid_name = "TCP-Friendly Rate Control",
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800845 .ccid_hc_tx_obj_size = sizeof(struct ccid3_hc_tx_sock),
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700846 .ccid_hc_tx_init = ccid3_hc_tx_init,
847 .ccid_hc_tx_exit = ccid3_hc_tx_exit,
848 .ccid_hc_tx_send_packet = ccid3_hc_tx_send_packet,
849 .ccid_hc_tx_packet_sent = ccid3_hc_tx_packet_sent,
850 .ccid_hc_tx_packet_recv = ccid3_hc_tx_packet_recv,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700851 .ccid_hc_tx_parse_options = ccid3_hc_tx_parse_options,
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800852 .ccid_hc_rx_obj_size = sizeof(struct ccid3_hc_rx_sock),
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700853 .ccid_hc_rx_init = ccid3_hc_rx_init,
854 .ccid_hc_rx_exit = ccid3_hc_rx_exit,
855 .ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options,
856 .ccid_hc_rx_packet_recv = ccid3_hc_rx_packet_recv,
Arnaldo Carvalho de Melo2babe1f2005-08-23 21:52:35 -0700857 .ccid_hc_rx_get_info = ccid3_hc_rx_get_info,
858 .ccid_hc_tx_get_info = ccid3_hc_tx_get_info,
Arnaldo Carvalho de Melo88f964d2005-09-18 00:19:32 -0700859 .ccid_hc_rx_getsockopt = ccid3_hc_rx_getsockopt,
860 .ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700861};
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200862
Gerrit Renker56724aa2006-11-20 18:28:09 -0200863#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
Gerrit Renker43264992008-08-23 13:28:27 +0200864module_param(ccid3_debug, bool, 0644);
Gerrit Renkerddebc972009-01-04 21:42:53 -0800865MODULE_PARM_DESC(ccid3_debug, "Enable CCID-3 debug messages");
Gerrit Renker56724aa2006-11-20 18:28:09 -0200866#endif