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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",
57 [TFRC_SSTATE_TERM] = "TERM",
58 };
59
60 return ccid3_state_names[state];
61}
62#endif
63
64static void ccid3_hc_tx_set_state(struct sock *sk,
65 enum ccid3_hc_tx_states state)
66{
Gerrit Renker996ccf42009-10-05 00:53:13 +000067 struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
68 enum ccid3_hc_tx_states oldstate = hc->tx_state;
Gerrit Renker410e27a2008-09-09 13:27:22 +020069
70 ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
71 dccp_role(sk), sk, ccid3_tx_state_name(oldstate),
72 ccid3_tx_state_name(state));
73 WARN_ON(state == oldstate);
Gerrit Renker996ccf42009-10-05 00:53:13 +000074 hc->tx_state = state;
Gerrit Renker410e27a2008-09-09 13:27:22 +020075}
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070076
Gerrit Renker17893bc2006-11-27 20:31:33 -020077/*
Gerrit Renker6c08b2c2007-11-20 17:33:17 -020078 * Compute the initial sending rate X_init in the manner of RFC 3390:
79 *
Gerrit Renker410e27a2008-09-09 13:27:22 +020080 * X_init = min(4 * s, max(2 * s, 4380 bytes)) / RTT
Gerrit Renker6c08b2c2007-11-20 17:33:17 -020081 *
Gerrit Renker410e27a2008-09-09 13:27:22 +020082 * Note that RFC 3390 uses MSS, RFC 4342 refers to RFC 3390, and rfc3448bis
83 * (rev-02) clarifies the use of RFC 3390 with regard to the above formula.
Gerrit Renkera21f9f92007-03-20 15:12:10 -030084 * For consistency with other parts of the code, X_init is scaled by 2^6.
85 */
86static inline u64 rfc3390_initial_rate(struct sock *sk)
87{
Gerrit Renker996ccf42009-10-05 00:53:13 +000088 const struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
89 const __u32 w_init = clamp_t(__u32, 4380U, 2 * hc->tx_s, 4 * hc->tx_s);
Gerrit Renkera21f9f92007-03-20 15:12:10 -030090
Gerrit Renker996ccf42009-10-05 00:53:13 +000091 return scaled_div(w_init << 6, hc->tx_rtt);
Gerrit Renkera21f9f92007-03-20 15:12:10 -030092}
93
Gerrit Renker20cbd3e2010-09-14 20:16:59 +020094/**
95 * ccid3_update_send_interval - Calculate new t_ipi = s / X_inst
96 * This respects the granularity of X_inst (64 * bytes/second).
Gerrit Renker17893bc2006-11-27 20:31:33 -020097 */
Gerrit Renker996ccf42009-10-05 00:53:13 +000098static void ccid3_update_send_interval(struct ccid3_hc_tx_sock *hc)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -070099{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000100 hc->tx_t_ipi = scaled_div32(((u64)hc->tx_s) << 6, hc->tx_x);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200101
Gerrit Renker20cbd3e2010-09-14 20:16:59 +0200102 ccid3_pr_debug("t_ipi=%u, s=%u, X=%u\n", hc->tx_t_ipi,
103 hc->tx_s, (unsigned)(hc->tx_x >> 6));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700104}
Gerrit Renkeraa97efd2007-09-25 22:39:16 -0700105
Gerrit Renker996ccf42009-10-05 00:53:13 +0000106static u32 ccid3_hc_tx_idle_rtt(struct ccid3_hc_tx_sock *hc, ktime_t now)
Gerrit Renkera5358fd2007-11-20 18:01:59 -0200107{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000108 u32 delta = ktime_us_delta(now, hc->tx_t_last_win_count);
Gerrit Renkera5358fd2007-11-20 18:01:59 -0200109
Gerrit Renker996ccf42009-10-05 00:53:13 +0000110 return delta / hc->tx_rtt;
Gerrit Renkera5358fd2007-11-20 18:01:59 -0200111}
112
Gerrit Renkeraa97efd2007-09-25 22:39:16 -0700113/**
114 * ccid3_hc_tx_update_x - Update allowed sending rate X
115 * @stamp: most recent time if available - can be left NULL.
116 * This function tracks draft rfc3448bis, check there for latest details.
Gerrit Renker5c3fbb62006-12-03 14:50:56 -0200117 *
Gerrit Renker1a21e492006-12-10 00:02:12 -0200118 * Note: X and X_recv are both stored in units of 64 * bytes/second, to support
119 * fine-grained resolution of sending rates. This requires scaling by 2^6
120 * throughout the code. Only X_calc is unscaled (in bytes/second).
121 *
Gerrit Renker1a21e492006-12-10 00:02:12 -0200122 */
Gerrit Renkeraa97efd2007-09-25 22:39:16 -0700123static void ccid3_hc_tx_update_x(struct sock *sk, ktime_t *stamp)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700124{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000125 struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
126 __u64 min_rate = 2 * hc->tx_x_recv;
127 const __u64 old_x = hc->tx_x;
Gerrit Renker52515e72007-12-17 12:57:43 -0200128 ktime_t now = stamp ? *stamp : ktime_get_real();
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700129
Gerrit Renker0c150ef2007-03-20 15:19:07 -0300130 /*
131 * Handle IDLE periods: do not reduce below RFC3390 initial sending rate
Gerrit Renkera5358fd2007-11-20 18:01:59 -0200132 * when idling [RFC 4342, 5.1]. Definition of idling is from rfc3448bis:
133 * a sender is idle if it has not sent anything over a 2-RTT-period.
Gerrit Renker0c150ef2007-03-20 15:19:07 -0300134 * For consistency with X and X_recv, min_rate is also scaled by 2^6.
135 */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000136 if (ccid3_hc_tx_idle_rtt(hc, now) >= 2) {
Gerrit Renker0c150ef2007-03-20 15:19:07 -0300137 min_rate = rfc3390_initial_rate(sk);
Gerrit Renker996ccf42009-10-05 00:53:13 +0000138 min_rate = max(min_rate, 2 * hc->tx_x_recv);
Gerrit Renker0c150ef2007-03-20 15:19:07 -0300139 }
140
Gerrit Renker996ccf42009-10-05 00:53:13 +0000141 if (hc->tx_p > 0) {
Gerrit Renker1a21e492006-12-10 00:02:12 -0200142
Gerrit Renker996ccf42009-10-05 00:53:13 +0000143 hc->tx_x = min(((__u64)hc->tx_x_calc) << 6, min_rate);
144 hc->tx_x = max(hc->tx_x, (((__u64)hc->tx_s) << 6) / TFRC_T_MBI);
Arnaldo Carvalho de Melob6ee3d42005-08-27 18:18:18 -0300145
Gerrit Renker996ccf42009-10-05 00:53:13 +0000146 } else if (ktime_us_delta(now, hc->tx_t_ld) - (s64)hc->tx_rtt >= 0) {
Gerrit Renker1a21e492006-12-10 00:02:12 -0200147
Gerrit Renker996ccf42009-10-05 00:53:13 +0000148 hc->tx_x = min(2 * hc->tx_x, min_rate);
149 hc->tx_x = max(hc->tx_x,
150 scaled_div(((__u64)hc->tx_s) << 6, hc->tx_rtt));
151 hc->tx_t_ld = now;
Gerrit Renkerff586292006-12-10 00:00:14 -0200152 }
Gerrit Renkera79ef762006-11-28 19:51:42 -0200153
Gerrit Renker996ccf42009-10-05 00:53:13 +0000154 if (hc->tx_x != old_x) {
Gerrit Renker1761f7d2007-03-20 15:04:30 -0300155 ccid3_pr_debug("X_prev=%u, X_now=%u, X_calc=%u, "
156 "X_recv=%u\n", (unsigned)(old_x >> 6),
Gerrit Renker996ccf42009-10-05 00:53:13 +0000157 (unsigned)(hc->tx_x >> 6), hc->tx_x_calc,
158 (unsigned)(hc->tx_x_recv >> 6));
Ian McDonald8699be72007-03-20 14:49:20 -0300159
Gerrit Renker996ccf42009-10-05 00:53:13 +0000160 ccid3_update_send_interval(hc);
Ian McDonald8699be72007-03-20 14:49:20 -0300161 }
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700162}
163
Gerrit Renker78ad7132006-11-28 19:22:33 -0200164/*
Gerrit Renker410e27a2008-09-09 13:27:22 +0200165 * Track the mean packet size `s' (cf. RFC 4342, 5.3 and RFC 3448, 4.1)
166 * @len: DCCP packet payload size in bytes
Gerrit Renker78ad7132006-11-28 19:22:33 -0200167 */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000168static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hc, int len)
Gerrit Renker78ad7132006-11-28 19:22:33 -0200169{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000170 const u16 old_s = hc->tx_s;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200171
Gerrit Renker996ccf42009-10-05 00:53:13 +0000172 hc->tx_s = tfrc_ewma(hc->tx_s, len, 9);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200173
Gerrit Renker996ccf42009-10-05 00:53:13 +0000174 if (hc->tx_s != old_s)
175 ccid3_update_send_interval(hc);
Gerrit Renker78ad7132006-11-28 19:22:33 -0200176}
177
Gerrit Renker9f8681d2006-12-10 00:07:37 -0200178/*
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200179 * Update Window Counter using the algorithm from [RFC 4342, 8.1].
Gerrit Renker825de272008-05-27 06:33:54 -0700180 * As elsewhere, RTT > 0 is assumed by using dccp_sample_rtt().
Gerrit Renker9f8681d2006-12-10 00:07:37 -0200181 */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000182static inline void ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock *hc,
Gerrit Renker8132da42007-06-16 13:34:02 -0300183 ktime_t now)
Gerrit Renker9f8681d2006-12-10 00:07:37 -0200184{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000185 u32 delta = ktime_us_delta(now, hc->tx_t_last_win_count),
186 quarter_rtts = (4 * delta) / hc->tx_rtt;
Gerrit Renker9f8681d2006-12-10 00:07:37 -0200187
188 if (quarter_rtts > 0) {
Gerrit Renker996ccf42009-10-05 00:53:13 +0000189 hc->tx_t_last_win_count = now;
190 hc->tx_last_win_count += min(quarter_rtts, 5U);
191 hc->tx_last_win_count &= 0xF; /* mod 16 */
Gerrit Renker9f8681d2006-12-10 00:07:37 -0200192 }
193}
194
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700195static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
196{
197 struct sock *sk = (struct sock *)data;
Gerrit Renker996ccf42009-10-05 00:53:13 +0000198 struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
Gerrit Renker2a1fda62006-11-28 18:34:34 -0200199 unsigned long t_nfb = USEC_PER_SEC / 5;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700200
201 bh_lock_sock(sk);
202 if (sock_owned_by_user(sk)) {
203 /* Try again later. */
204 /* XXX: set some sensible MIB */
Gerrit Renker48e03ee2006-11-27 20:29:27 -0200205 goto restart_timer;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700206 }
207
Frans Popb1383382010-03-24 07:57:28 +0000208 ccid3_pr_debug("%s(%p, state=%s) - entry\n", dccp_role(sk), sk,
Gerrit Renker996ccf42009-10-05 00:53:13 +0000209 ccid3_tx_state_name(hc->tx_state));
Gerrit Renkera9672412006-12-10 00:14:12 -0200210
Gerrit Renker996ccf42009-10-05 00:53:13 +0000211 if (hc->tx_state == TFRC_SSTATE_FBACK)
Gerrit Renker410e27a2008-09-09 13:27:22 +0200212 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
Gerrit Renker996ccf42009-10-05 00:53:13 +0000213 else if (hc->tx_state != TFRC_SSTATE_NO_FBACK)
Gerrit Renkerd0995e62008-09-04 07:30:19 +0200214 goto out;
215
Gerrit Renker52515e72007-12-17 12:57:43 -0200216 /*
217 * Determine new allowed sending rate X as per draft rfc3448bis-00, 4.4
Gerrit Renker67b67e32010-08-22 19:41:36 +0000218 * RTO is 0 if and only if no feedback has been received yet.
Gerrit Renker52515e72007-12-17 12:57:43 -0200219 */
Gerrit Renker67b67e32010-08-22 19:41:36 +0000220 if (hc->tx_t_rto == 0 || hc->tx_p == 0) {
Gerrit Renker52515e72007-12-17 12:57:43 -0200221
222 /* halve send rate directly */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000223 hc->tx_x = max(hc->tx_x / 2,
224 (((__u64)hc->tx_s) << 6) / TFRC_T_MBI);
225 ccid3_update_send_interval(hc);
Gerrit Renker52515e72007-12-17 12:57:43 -0200226 } else {
Arnaldo Carvalho de Melo1f2333a2005-08-27 03:51:58 -0300227 /*
Gerrit Renker52515e72007-12-17 12:57:43 -0200228 * Modify the cached value of X_recv
Gerrit Renker0c150ef2007-03-20 15:19:07 -0300229 *
Gerrit Renker52515e72007-12-17 12:57:43 -0200230 * If (X_calc > 2 * X_recv)
Gerrit Renker0c150ef2007-03-20 15:19:07 -0300231 * X_recv = max(X_recv / 2, s / (2 * t_mbi));
232 * Else
233 * X_recv = X_calc / 4;
234 *
235 * Note that X_recv is scaled by 2^6 while X_calc is not
Arnaldo Carvalho de Melo1f2333a2005-08-27 03:51:58 -0300236 */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000237 BUG_ON(hc->tx_p && !hc->tx_x_calc);
Gerrit Renkera79ef762006-11-28 19:51:42 -0200238
Gerrit Renker996ccf42009-10-05 00:53:13 +0000239 if (hc->tx_x_calc > (hc->tx_x_recv >> 5))
240 hc->tx_x_recv =
241 max(hc->tx_x_recv / 2,
242 (((__u64)hc->tx_s) << 6) / (2*TFRC_T_MBI));
Gerrit Renker52515e72007-12-17 12:57:43 -0200243 else {
Gerrit Renker996ccf42009-10-05 00:53:13 +0000244 hc->tx_x_recv = hc->tx_x_calc;
245 hc->tx_x_recv <<= 4;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700246 }
Gerrit Renkeraa97efd2007-09-25 22:39:16 -0700247 ccid3_hc_tx_update_x(sk, NULL);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700248 }
Gerrit Renker52515e72007-12-17 12:57:43 -0200249 ccid3_pr_debug("Reduced X to %llu/64 bytes/sec\n",
Gerrit Renker996ccf42009-10-05 00:53:13 +0000250 (unsigned long long)hc->tx_x);
Gerrit Renker52515e72007-12-17 12:57:43 -0200251
252 /*
253 * Set new timeout for the nofeedback timer.
254 * See comments in packet_recv() regarding the value of t_RTO.
255 */
Gerrit Renker67b67e32010-08-22 19:41:36 +0000256 if (unlikely(hc->tx_t_rto == 0)) /* no feedback received yet */
Gerrit Renker52515e72007-12-17 12:57:43 -0200257 t_nfb = TFRC_INITIAL_TIMEOUT;
258 else
Gerrit Renker996ccf42009-10-05 00:53:13 +0000259 t_nfb = max(hc->tx_t_rto, 2 * hc->tx_t_ipi);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700260
Gerrit Renker48e03ee2006-11-27 20:29:27 -0200261restart_timer:
Gerrit Renker996ccf42009-10-05 00:53:13 +0000262 sk_reset_timer(sk, &hc->tx_no_feedback_timer,
YOSHIFUJI Hideakic9eaf172007-02-09 23:24:38 +0900263 jiffies + usecs_to_jiffies(t_nfb));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700264out:
265 bh_unlock_sock(sk);
266 sock_put(sk);
267}
268
Gerrit Renker410e27a2008-09-09 13:27:22 +0200269/*
270 * returns
271 * > 0: delay (in msecs) that should pass before actually sending
272 * = 0: can send immediately
273 * < 0: error condition; do not send packet
Gerrit Renker7da7f452006-11-27 12:26:03 -0200274 */
Gerrit Renker6b57c932006-11-28 19:55:06 -0200275static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700276{
277 struct dccp_sock *dp = dccp_sk(sk);
Gerrit Renker996ccf42009-10-05 00:53:13 +0000278 struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
Gerrit Renker8132da42007-06-16 13:34:02 -0300279 ktime_t now = ktime_get_real();
280 s64 delay;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700281
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700282 /*
Gerrit Renkerda335ba2006-11-27 12:26:57 -0200283 * This function is called only for Data and DataAck packets. Sending
284 * zero-sized Data(Ack)s is theoretically possible, but for congestion
285 * control this case is pathological - ignore it.
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700286 */
Gerrit Renker6b57c932006-11-28 19:55:06 -0200287 if (unlikely(skb->len == 0))
Gerrit Renkerda335ba2006-11-27 12:26:57 -0200288 return -EBADMSG;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700289
Gerrit Renker996ccf42009-10-05 00:53:13 +0000290 switch (hc->tx_state) {
Gerrit Renker410e27a2008-09-09 13:27:22 +0200291 case TFRC_SSTATE_NO_SENT:
Gerrit Renker996ccf42009-10-05 00:53:13 +0000292 sk_reset_timer(sk, &hc->tx_no_feedback_timer, (jiffies +
293 usecs_to_jiffies(TFRC_INITIAL_TIMEOUT)));
294 hc->tx_last_win_count = 0;
295 hc->tx_t_last_win_count = now;
Gerrit Renker90feeb92006-11-27 12:13:38 -0200296
297 /* Set t_0 for initial packet */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000298 hc->tx_t_nom = now;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200299
Gerrit Renker996ccf42009-10-05 00:53:13 +0000300 hc->tx_s = skb->len;
Gerrit Renker30833ff2007-03-20 15:31:56 -0300301
Gerrit Renker30833ff2007-03-20 15:31:56 -0300302 /*
303 * Use initial RTT sample when available: recommended by erratum
304 * to RFC 4342. This implements the initialisation procedure of
305 * draft rfc3448bis, section 4.2. Remember, X is scaled by 2^6.
306 */
307 if (dp->dccps_syn_rtt) {
308 ccid3_pr_debug("SYN RTT = %uus\n", dp->dccps_syn_rtt);
Gerrit Renker996ccf42009-10-05 00:53:13 +0000309 hc->tx_rtt = dp->dccps_syn_rtt;
310 hc->tx_x = rfc3390_initial_rate(sk);
311 hc->tx_t_ld = now;
Gerrit Renker30833ff2007-03-20 15:31:56 -0300312 } else {
Gerrit Renker3294f202008-06-11 11:19:09 +0100313 /*
314 * Sender does not have RTT sample:
315 * - set fallback RTT (RFC 4340, 3.4) since a RTT value
316 * is needed in several parts (e.g. window counter);
317 * - set sending rate X_pps = 1pps as per RFC 3448, 4.2.
318 */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000319 hc->tx_rtt = DCCP_FALLBACK_RTT;
320 hc->tx_x = hc->tx_s;
321 hc->tx_x <<= 6;
Gerrit Renker30833ff2007-03-20 15:31:56 -0300322 }
Gerrit Renker996ccf42009-10-05 00:53:13 +0000323 ccid3_update_send_interval(hc);
Gerrit Renker30833ff2007-03-20 15:31:56 -0300324
Gerrit Renker410e27a2008-09-09 13:27:22 +0200325 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
326 break;
327 case TFRC_SSTATE_NO_FBACK:
328 case TFRC_SSTATE_FBACK:
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);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200343 break;
344 case TFRC_SSTATE_TERM:
345 DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
346 return -EINVAL;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700347 }
348
Gerrit Renker7da7f452006-11-27 12:26:03 -0200349 /* prepare to send now (add options etc.) */
350 dp->dccps_hc_tx_insert_options = 1;
Gerrit Renker996ccf42009-10-05 00:53:13 +0000351 DCCP_SKB_CB(skb)->dccpd_ccval = hc->tx_last_win_count;
Gerrit Renkere312d102006-12-10 00:08:09 -0200352
353 /* set the nominal send time for the next following packet */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000354 hc->tx_t_nom = ktime_add_us(hc->tx_t_nom, hc->tx_t_ipi);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200355 return 0;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700356}
357
Gerrit Renker410e27a2008-09-09 13:27:22 +0200358static void ccid3_hc_tx_packet_sent(struct sock *sk, int more,
359 unsigned int len)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700360{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000361 struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700362
Gerrit Renker996ccf42009-10-05 00:53:13 +0000363 ccid3_hc_tx_update_s(hc, len);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700364
Gerrit Renker996ccf42009-10-05 00:53:13 +0000365 if (tfrc_tx_hist_add(&hc->tx_hist, dccp_sk(sk)->dccps_gss))
Gerrit Renkerc5a1ae92006-12-10 00:09:21 -0200366 DCCP_CRIT("packet history - out of memory!");
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700367}
368
369static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
370{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000371 struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
Gerrit Renker67b67e32010-08-22 19:41:36 +0000372 struct ccid3_options_received *opt_recv = &hc->tx_options_received;
Gerrit Renkerd2c72632010-09-14 20:18:00 +0200373 struct tfrc_tx_hist_entry *acked;
Arnaldo Carvalho de Melo0740d492007-08-19 17:18:13 -0700374 ktime_t now;
Gerrit Renker2a1fda62006-11-28 18:34:34 -0200375 unsigned long t_nfb;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200376 u32 pinv, r_sample;
Arnaldo Carvalho de Melo1f2333a2005-08-27 03:51:58 -0300377
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700378 /* we are only interested in ACKs */
379 if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
380 DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
381 return;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200382 /* ... and only in the established state */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000383 if (hc->tx_state != TFRC_SSTATE_FBACK &&
384 hc->tx_state != TFRC_SSTATE_NO_FBACK)
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200385 return;
Gerrit Renker63b3a732008-09-04 07:30:19 +0200386
Gerrit Renkerd2c72632010-09-14 20:18:00 +0200387 /*
388 * Locate the acknowledged packet in the TX history.
389 *
390 * Returning "entry not found" here can for instance happen when
391 * - the host has not sent out anything (e.g. a passive server),
392 * - the Ack is outdated (packet with higher Ack number was received),
393 * - it is a bogus Ack (for a packet not sent on this connection).
394 */
395 acked = tfrc_tx_hist_find_entry(hc->tx_hist, dccp_hdr_ack_seq(skb));
396 if (acked == NULL)
Gerrit Renker410e27a2008-09-09 13:27:22 +0200397 return;
Gerrit Renkerd2c72632010-09-14 20:18:00 +0200398 /* For the sake of RTT sampling, ignore/remove all older entries */
399 tfrc_tx_hist_purge(&acked->next);
400
401 /* Update the moving average for the RTT estimate (RFC 3448, 4.3) */
402 now = ktime_get_real();
403 r_sample = dccp_sample_rtt(sk, ktime_us_delta(now, acked->stamp));
404 hc->tx_rtt = tfrc_ewma(hc->tx_rtt, r_sample, 9);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200405
406 /* Update receive rate in units of 64 * bytes/second */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000407 hc->tx_x_recv = opt_recv->ccid3or_receive_rate;
408 hc->tx_x_recv <<= 6;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200409
410 /* Update loss event rate (which is scaled by 1e6) */
411 pinv = opt_recv->ccid3or_loss_event_rate;
412 if (pinv == ~0U || pinv == 0) /* see RFC 4342, 8.5 */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000413 hc->tx_p = 0;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200414 else /* can not exceed 100% */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000415 hc->tx_p = scaled_div(1, pinv);
Gerrit Renkerd2c72632010-09-14 20:18:00 +0200416
Gerrit Renkerd8d12522007-12-17 12:48:47 -0200417 /*
418 * Update allowed sending rate X as per draft rfc3448bis-00, 4.2/3
419 */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000420 if (hc->tx_state == TFRC_SSTATE_NO_FBACK) {
Gerrit Renker410e27a2008-09-09 13:27:22 +0200421 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200422
Gerrit Renker996ccf42009-10-05 00:53:13 +0000423 if (hc->tx_t_rto == 0) {
Gerrit Renkerd8d12522007-12-17 12:48:47 -0200424 /*
425 * Initial feedback packet: Larger Initial Windows (4.2)
426 */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000427 hc->tx_x = rfc3390_initial_rate(sk);
428 hc->tx_t_ld = now;
Gerrit Renkerd8d12522007-12-17 12:48:47 -0200429
Gerrit Renker996ccf42009-10-05 00:53:13 +0000430 ccid3_update_send_interval(hc);
Gerrit Renkerd8d12522007-12-17 12:48:47 -0200431
432 goto done_computing_x;
Gerrit Renker996ccf42009-10-05 00:53:13 +0000433 } else if (hc->tx_p == 0) {
Gerrit Renkerd8d12522007-12-17 12:48:47 -0200434 /*
435 * First feedback after nofeedback timer expiry (4.3)
436 */
437 goto done_computing_x;
438 }
439 }
440
441 /* Update sending rate (step 4 of [RFC 3448, 4.3]) */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000442 if (hc->tx_p > 0)
443 hc->tx_x_calc = tfrc_calc_x(hc->tx_s, hc->tx_rtt, hc->tx_p);
Gerrit Renkerd8d12522007-12-17 12:48:47 -0200444 ccid3_hc_tx_update_x(sk, &now);
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200445
Gerrit Renkerd8d12522007-12-17 12:48:47 -0200446done_computing_x:
447 ccid3_pr_debug("%s(%p), RTT=%uus (sample=%uus), s=%u, "
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200448 "p=%u, X_calc=%u, X_recv=%u, X=%u\n",
Gerrit Renker996ccf42009-10-05 00:53:13 +0000449 dccp_role(sk), sk, hc->tx_rtt, r_sample,
450 hc->tx_s, hc->tx_p, hc->tx_x_calc,
451 (unsigned)(hc->tx_x_recv >> 6),
452 (unsigned)(hc->tx_x >> 6));
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200453
454 /* unschedule no feedback timer */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000455 sk_stop_timer(sk, &hc->tx_no_feedback_timer);
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200456
457 /*
458 * As we have calculated new ipi, delta, t_nom it is possible
459 * that we now can send a packet, so wake up dccp_wait_for_ccid
460 */
461 sk->sk_write_space(sk);
462
463 /*
Gerrit Renker89858ad2010-08-29 19:23:14 +0000464 * Update timeout interval for the nofeedback timer. In order to control
465 * rate halving on networks with very low RTTs (<= 1 ms), use per-route
466 * tunable RTAX_RTO_MIN value as the lower bound.
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200467 */
Gerrit Renker89858ad2010-08-29 19:23:14 +0000468 hc->tx_t_rto = max_t(u32, 4 * hc->tx_rtt,
469 USEC_PER_SEC/HZ * tcp_rto_min(sk));
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200470 /*
471 * Schedule no feedback timer to expire in
472 * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
473 */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000474 t_nfb = max(hc->tx_t_rto, 2 * hc->tx_t_ipi);
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200475
476 ccid3_pr_debug("%s(%p), Scheduled no feedback timer to "
477 "expire in %lu jiffies (%luus)\n",
Gerrit Renker388d5e92009-10-05 00:53:11 +0000478 dccp_role(sk), sk, usecs_to_jiffies(t_nfb), t_nfb);
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200479
Gerrit Renker996ccf42009-10-05 00:53:13 +0000480 sk_reset_timer(sk, &hc->tx_no_feedback_timer,
Gerrit Renker5bd370a2007-12-17 10:25:06 -0200481 jiffies + usecs_to_jiffies(t_nfb));
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700482}
483
Gerrit Renker410e27a2008-09-09 13:27:22 +0200484static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
485 unsigned char len, u16 idx,
486 unsigned char *value)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700487{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000488 struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
Gerrit Renker67b67e32010-08-22 19:41:36 +0000489 struct ccid3_options_received *opt_recv = &hc->tx_options_received;
Gerrit Renker76fd1e82007-10-24 10:46:58 -0200490 __be32 opt_val;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700491
Gerrit Renker410e27a2008-09-09 13:27:22 +0200492 switch (option) {
Gerrit Renker37efb032010-09-14 20:21:29 +0200493 case TFRC_OPT_RECEIVE_RATE:
Gerrit Renker410e27a2008-09-09 13:27:22 +0200494 case TFRC_OPT_LOSS_EVENT_RATE:
495 if (unlikely(len != 4)) {
Gerrit Renker37efb032010-09-14 20:21:29 +0200496 DCCP_WARN("%s(%p), invalid len %d for %u\n",
497 dccp_role(sk), sk, len, option);
498 return -EINVAL;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200499 }
Gerrit Renker37efb032010-09-14 20:21:29 +0200500 opt_val = ntohl(get_unaligned((__be32 *)value));
Gerrit Renker410e27a2008-09-09 13:27:22 +0200501
Gerrit Renker37efb032010-09-14 20:21:29 +0200502 if (option == TFRC_OPT_RECEIVE_RATE) {
503 opt_recv->ccid3or_receive_rate = opt_val;
504 ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n",
505 dccp_role(sk), sk, opt_val);
506 } else {
507 opt_recv->ccid3or_loss_event_rate = opt_val;
508 ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n",
509 dccp_role(sk), sk, opt_val);
510 }
511 }
512 return 0;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700513}
514
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800515static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700516{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000517 struct ccid3_hc_tx_sock *hc = ccid_priv(ccid);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700518
Gerrit Renker996ccf42009-10-05 00:53:13 +0000519 hc->tx_state = TFRC_SSTATE_NO_SENT;
520 hc->tx_hist = NULL;
521 setup_timer(&hc->tx_no_feedback_timer,
Gerrit Renker410e27a2008-09-09 13:27:22 +0200522 ccid3_hc_tx_no_feedback_timer, (unsigned long)sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700523 return 0;
524}
525
526static void ccid3_hc_tx_exit(struct sock *sk)
527{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000528 struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700529
Gerrit Renker410e27a2008-09-09 13:27:22 +0200530 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM);
Gerrit Renker996ccf42009-10-05 00:53:13 +0000531 sk_stop_timer(sk, &hc->tx_no_feedback_timer);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200532
Gerrit Renker996ccf42009-10-05 00:53:13 +0000533 tfrc_tx_hist_purge(&hc->tx_hist);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700534}
535
Gerrit Renker9bf17472007-03-20 13:11:24 -0300536static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info)
537{
Gerrit Renker51c22bb2010-08-22 19:41:37 +0000538 info->tcpi_rto = ccid3_hc_tx_sk(sk)->tx_t_rto;
539 info->tcpi_rtt = ccid3_hc_tx_sk(sk)->tx_rtt;
Gerrit Renker9bf17472007-03-20 13:11:24 -0300540}
541
542static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
543 u32 __user *optval, int __user *optlen)
544{
Gerrit Renker51c22bb2010-08-22 19:41:37 +0000545 const struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
Gerrit Renker67b67e32010-08-22 19:41:36 +0000546 struct tfrc_tx_info tfrc;
Gerrit Renker9bf17472007-03-20 13:11:24 -0300547 const void *val;
548
Gerrit Renker9bf17472007-03-20 13:11:24 -0300549 switch (optname) {
550 case DCCP_SOCKOPT_CCID_TX_INFO:
Gerrit Renker67b67e32010-08-22 19:41:36 +0000551 if (len < sizeof(tfrc))
Gerrit Renker9bf17472007-03-20 13:11:24 -0300552 return -EINVAL;
Gerrit Renker67b67e32010-08-22 19:41:36 +0000553 tfrc.tfrctx_x = hc->tx_x;
554 tfrc.tfrctx_x_recv = hc->tx_x_recv;
555 tfrc.tfrctx_x_calc = hc->tx_x_calc;
556 tfrc.tfrctx_rtt = hc->tx_rtt;
557 tfrc.tfrctx_p = hc->tx_p;
558 tfrc.tfrctx_rto = hc->tx_t_rto;
559 tfrc.tfrctx_ipi = hc->tx_t_ipi;
560 len = sizeof(tfrc);
561 val = &tfrc;
Gerrit Renker9bf17472007-03-20 13:11:24 -0300562 break;
563 default:
564 return -ENOPROTOOPT;
565 }
566
567 if (put_user(len, optlen) || copy_to_user(optval, val, len))
568 return -EFAULT;
569
570 return 0;
571}
572
573/*
574 * Receiver Half-Connection Routines
575 */
Gerrit Renker410e27a2008-09-09 13:27:22 +0200576
577/* CCID3 feedback types */
578enum ccid3_fback_type {
579 CCID3_FBACK_NONE = 0,
580 CCID3_FBACK_INITIAL,
581 CCID3_FBACK_PERIODIC,
582 CCID3_FBACK_PARAM_CHANGE
583};
584
585#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
586static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
587{
Jan Engelhardt36cbd3d2009-08-05 10:42:58 -0700588 static const char *const ccid3_rx_state_names[] = {
Gerrit Renker410e27a2008-09-09 13:27:22 +0200589 [TFRC_RSTATE_NO_DATA] = "NO_DATA",
590 [TFRC_RSTATE_DATA] = "DATA",
591 [TFRC_RSTATE_TERM] = "TERM",
592 };
593
594 return ccid3_rx_state_names[state];
595}
596#endif
597
598static void ccid3_hc_rx_set_state(struct sock *sk,
599 enum ccid3_hc_rx_states state)
600{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000601 struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
602 enum ccid3_hc_rx_states oldstate = hc->rx_state;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200603
604 ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
605 dccp_role(sk), sk, ccid3_rx_state_name(oldstate),
606 ccid3_rx_state_name(state));
607 WARN_ON(state == oldstate);
Gerrit Renker996ccf42009-10-05 00:53:13 +0000608 hc->rx_state = state;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200609}
610
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200611static void ccid3_hc_rx_send_feedback(struct sock *sk,
612 const struct sk_buff *skb,
613 enum ccid3_fback_type fbtype)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700614{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000615 struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200616 struct dccp_sock *dp = dccp_sk(sk);
617 ktime_t now;
618 s64 delta = 0;
619
Gerrit Renker996ccf42009-10-05 00:53:13 +0000620 if (unlikely(hc->rx_state == TFRC_RSTATE_TERM))
Gerrit Renker410e27a2008-09-09 13:27:22 +0200621 return;
622
623 now = ktime_get_real();
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700624
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200625 switch (fbtype) {
626 case CCID3_FBACK_INITIAL:
Gerrit Renker996ccf42009-10-05 00:53:13 +0000627 hc->rx_x_recv = 0;
628 hc->rx_pinv = ~0U; /* see RFC 4342, 8.5 */
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700629 break;
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200630 case CCID3_FBACK_PARAM_CHANGE:
631 /*
632 * When parameters change (new loss or p > p_prev), we do not
633 * have a reliable estimate for R_m of [RFC 3448, 6.2] and so
Gerrit Renker410e27a2008-09-09 13:27:22 +0200634 * need to reuse the previous value of X_recv. However, when
635 * X_recv was 0 (due to early loss), this would kill X down to
636 * s/t_mbi (i.e. one packet in 64 seconds).
637 * To avoid such drastic reduction, we approximate X_recv as
638 * the number of bytes since last feedback.
639 * This is a safe fallback, since X is bounded above by X_calc.
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200640 */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000641 if (hc->rx_x_recv > 0)
Gerrit Renker410e27a2008-09-09 13:27:22 +0200642 break;
643 /* fall through */
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200644 case CCID3_FBACK_PERIODIC:
Gerrit Renker996ccf42009-10-05 00:53:13 +0000645 delta = ktime_us_delta(now, hc->rx_tstamp_last_feedback);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200646 if (delta <= 0)
647 DCCP_BUG("delta (%ld) <= 0", (long)delta);
648 else
Gerrit Renker996ccf42009-10-05 00:53:13 +0000649 hc->rx_x_recv = scaled_div32(hc->rx_bytes_recv, delta);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700650 break;
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200651 default:
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700652 return;
653 }
654
Gerrit Renker410e27a2008-09-09 13:27:22 +0200655 ccid3_pr_debug("Interval %ldusec, X_recv=%u, 1/p=%u\n", (long)delta,
Gerrit Renker996ccf42009-10-05 00:53:13 +0000656 hc->rx_x_recv, hc->rx_pinv);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700657
Gerrit Renker996ccf42009-10-05 00:53:13 +0000658 hc->rx_tstamp_last_feedback = now;
659 hc->rx_last_counter = dccp_hdr(skb)->dccph_ccval;
660 hc->rx_bytes_recv = 0;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200661
662 dp->dccps_hc_rx_insert_options = 1;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700663 dccp_send_ack(sk);
664}
665
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -0800666static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700667{
Gerrit Renker51c22bb2010-08-22 19:41:37 +0000668 const struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
Andrea Bittau60fe62e2006-03-20 19:23:32 -0800669 __be32 x_recv, pinv;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700670
Arnaldo Carvalho de Melo59d203f2005-09-09 20:01:25 -0300671 if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -0800672 return 0;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700673
Arnaldo Carvalho de Melo4fded332005-08-23 21:51:59 -0700674 if (dccp_packet_without_ack(skb))
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -0800675 return 0;
676
Gerrit Renker996ccf42009-10-05 00:53:13 +0000677 x_recv = htonl(hc->rx_x_recv);
678 pinv = htonl(hc->rx_pinv);
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -0800679
Gerrit Renkera7d13fb2010-06-22 01:14:34 +0000680 if (dccp_insert_option(skb, TFRC_OPT_LOSS_EVENT_RATE,
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200681 &pinv, sizeof(pinv)) ||
Gerrit Renkera7d13fb2010-06-22 01:14:34 +0000682 dccp_insert_option(skb, TFRC_OPT_RECEIVE_RATE,
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200683 &x_recv, sizeof(x_recv)))
Arnaldo Carvalho de Melo2d0817d2006-03-20 22:32:06 -0800684 return -1;
685
686 return 0;
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700687}
688
Gerrit Renkeraa1b1ff2009-09-12 07:47:01 +0000689/**
690 * ccid3_first_li - Implements [RFC 5348, 6.3.1]
Gerrit Renker954c2db2007-12-12 14:06:14 -0200691 *
692 * Determine the length of the first loss interval via inverse lookup.
693 * Assume that X_recv can be computed by the throughput equation
694 * s
695 * X_recv = --------
696 * R * fval
697 * Find some p such that f(p) = fval; return 1/p (scaled).
698 */
699static u32 ccid3_first_li(struct sock *sk)
700{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000701 struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200702 u32 x_recv, p, delta;
Gerrit Renker954c2db2007-12-12 14:06:14 -0200703 u64 fval;
704
Gerrit Renker996ccf42009-10-05 00:53:13 +0000705 if (hc->rx_rtt == 0) {
Gerrit Renker410e27a2008-09-09 13:27:22 +0200706 DCCP_WARN("No RTT estimate available, using fallback RTT\n");
Gerrit Renker996ccf42009-10-05 00:53:13 +0000707 hc->rx_rtt = DCCP_FALLBACK_RTT;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200708 }
Gerrit Renkerd20ed952008-09-04 07:30:19 +0200709
Gerrit Renker996ccf42009-10-05 00:53:13 +0000710 delta = ktime_to_us(net_timedelta(hc->rx_tstamp_last_feedback));
711 x_recv = scaled_div32(hc->rx_bytes_recv, delta);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200712 if (x_recv == 0) { /* would also trigger divide-by-zero */
713 DCCP_WARN("X_recv==0\n");
Gerrit Renker67b67e32010-08-22 19:41:36 +0000714 if (hc->rx_x_recv == 0) {
Gerrit Renker410e27a2008-09-09 13:27:22 +0200715 DCCP_BUG("stored value of X_recv is zero");
716 return ~0U;
717 }
Gerrit Renker67b67e32010-08-22 19:41:36 +0000718 x_recv = hc->rx_x_recv;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200719 }
Gerrit Renker954c2db2007-12-12 14:06:14 -0200720
Gerrit Renker996ccf42009-10-05 00:53:13 +0000721 fval = scaled_div(hc->rx_s, hc->rx_rtt);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200722 fval = scaled_div32(fval, x_recv);
Gerrit Renker954c2db2007-12-12 14:06:14 -0200723 p = tfrc_calc_x_reverse_lookup(fval);
724
725 ccid3_pr_debug("%s(%p), receive rate=%u bytes/s, implied "
726 "loss rate=%u\n", dccp_role(sk), sk, x_recv, p);
727
Gerrit Renker410e27a2008-09-09 13:27:22 +0200728 return p == 0 ? ~0U : scaled_div(1, p);
Gerrit Renker954c2db2007-12-12 14:06:14 -0200729}
730
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700731static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
732{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000733 struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200734 enum ccid3_fback_type do_feedback = CCID3_FBACK_NONE;
Gerrit Renker5b5d0e72008-07-13 11:51:40 +0100735 const u64 ndp = dccp_sk(sk)->dccps_options_received.dccpor_ndp;
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200736 const bool is_data_packet = dccp_data_packet(skb);
Arnaldo Carvalho de Melo1f2333a2005-08-27 03:51:58 -0300737
Gerrit Renker996ccf42009-10-05 00:53:13 +0000738 if (unlikely(hc->rx_state == TFRC_RSTATE_NO_DATA)) {
Gerrit Renker410e27a2008-09-09 13:27:22 +0200739 if (is_data_packet) {
740 const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4;
741 do_feedback = CCID3_FBACK_INITIAL;
742 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA);
Gerrit Renker996ccf42009-10-05 00:53:13 +0000743 hc->rx_s = payload;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200744 /*
Gerrit Renker388d5e92009-10-05 00:53:11 +0000745 * Not necessary to update rx_bytes_recv here,
Gerrit Renker410e27a2008-09-09 13:27:22 +0200746 * since X_recv = 0 for the first feedback packet (cf.
747 * RFC 3448, 6.3) -- gerrit
748 */
749 }
750 goto update_records;
751 }
752
Gerrit Renker996ccf42009-10-05 00:53:13 +0000753 if (tfrc_rx_hist_duplicate(&hc->rx_hist, skb))
Gerrit Renker410e27a2008-09-09 13:27:22 +0200754 return; /* done receiving */
755
756 if (is_data_packet) {
757 const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4;
758 /*
759 * Update moving-average of s and the sum of received payload bytes
760 */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000761 hc->rx_s = tfrc_ewma(hc->rx_s, payload, 9);
762 hc->rx_bytes_recv += payload;
Gerrit Renker410e27a2008-09-09 13:27:22 +0200763 }
764
Gerrit Renkerd20ed952008-09-04 07:30:19 +0200765 /*
766 * Perform loss detection and handle pending losses
767 */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000768 if (tfrc_rx_handle_loss(&hc->rx_hist, &hc->rx_li_hist,
Gerrit Renker410e27a2008-09-09 13:27:22 +0200769 skb, ndp, ccid3_first_li, sk)) {
770 do_feedback = CCID3_FBACK_PARAM_CHANGE;
771 goto done_receiving;
772 }
773
Gerrit Renker996ccf42009-10-05 00:53:13 +0000774 if (tfrc_rx_hist_loss_pending(&hc->rx_hist))
Gerrit Renker410e27a2008-09-09 13:27:22 +0200775 return; /* done receiving */
776
Gerrit Renker88e97a92008-09-04 07:30:19 +0200777 /*
Gerrit Renker410e27a2008-09-09 13:27:22 +0200778 * Handle data packets: RTT sampling and monitoring p
Gerrit Renker88e97a92008-09-04 07:30:19 +0200779 */
Gerrit Renker410e27a2008-09-09 13:27:22 +0200780 if (unlikely(!is_data_packet))
781 goto update_records;
782
Gerrit Renker996ccf42009-10-05 00:53:13 +0000783 if (!tfrc_lh_is_initialised(&hc->rx_li_hist)) {
784 const u32 sample = tfrc_rx_hist_sample_rtt(&hc->rx_hist, skb);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200785 /*
786 * Empty loss history: no loss so far, hence p stays 0.
787 * Sample RTT values, since an RTT estimate is required for the
788 * computation of p when the first loss occurs; RFC 3448, 6.3.1.
789 */
790 if (sample != 0)
Gerrit Renker996ccf42009-10-05 00:53:13 +0000791 hc->rx_rtt = tfrc_ewma(hc->rx_rtt, sample, 9);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200792
Gerrit Renker996ccf42009-10-05 00:53:13 +0000793 } else if (tfrc_lh_update_i_mean(&hc->rx_li_hist, skb)) {
Gerrit Renker410e27a2008-09-09 13:27:22 +0200794 /*
795 * Step (3) of [RFC 3448, 6.1]: Recompute I_mean and, if I_mean
796 * has decreased (resp. p has increased), send feedback now.
797 */
798 do_feedback = CCID3_FBACK_PARAM_CHANGE;
799 }
800
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200801 /*
Arnaldo Carvalho de Melob84a2182007-12-06 13:18:11 -0200802 * Check if the periodic once-per-RTT feedback is due; RFC 4342, 10.3
803 */
Gerrit Renker996ccf42009-10-05 00:53:13 +0000804 if (SUB16(dccp_hdr(skb)->dccph_ccval, hc->rx_last_counter) > 3)
Gerrit Renker410e27a2008-09-09 13:27:22 +0200805 do_feedback = CCID3_FBACK_PERIODIC;
806
807update_records:
Gerrit Renker996ccf42009-10-05 00:53:13 +0000808 tfrc_rx_hist_add_packet(&hc->rx_hist, skb, ndp);
Gerrit Renker410e27a2008-09-09 13:27:22 +0200809
810done_receiving:
811 if (do_feedback)
812 ccid3_hc_rx_send_feedback(sk, skb, do_feedback);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700813}
814
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800815static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700816{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000817 struct ccid3_hc_rx_sock *hc = ccid_priv(ccid);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700818
Gerrit Renker996ccf42009-10-05 00:53:13 +0000819 hc->rx_state = TFRC_RSTATE_NO_DATA;
820 tfrc_lh_init(&hc->rx_li_hist);
821 return tfrc_rx_hist_alloc(&hc->rx_hist);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700822}
823
824static void ccid3_hc_rx_exit(struct sock *sk)
825{
Gerrit Renker996ccf42009-10-05 00:53:13 +0000826 struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700827
Gerrit Renker410e27a2008-09-09 13:27:22 +0200828 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM);
829
Gerrit Renker996ccf42009-10-05 00:53:13 +0000830 tfrc_rx_hist_purge(&hc->rx_hist);
831 tfrc_lh_cleanup(&hc->rx_li_hist);
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700832}
833
Arnaldo Carvalho de Melo2babe1f2005-08-23 21:52:35 -0700834static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
835{
Gerrit Renker51c22bb2010-08-22 19:41:37 +0000836 info->tcpi_ca_state = ccid3_hc_rx_sk(sk)->rx_state;
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200837 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
Gerrit Renker51c22bb2010-08-22 19:41:37 +0000838 info->tcpi_rcv_rtt = ccid3_hc_rx_sk(sk)->rx_rtt;
Arnaldo Carvalho de Melo2babe1f2005-08-23 21:52:35 -0700839}
840
Arnaldo Carvalho de Melo88f964d2005-09-18 00:19:32 -0700841static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len,
842 u32 __user *optval, int __user *optlen)
843{
Gerrit Renker51c22bb2010-08-22 19:41:37 +0000844 const struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
Gerrit Renker8e138e72007-12-17 10:07:44 -0200845 struct tfrc_rx_info rx_info;
Arnaldo Carvalho de Melo88f964d2005-09-18 00:19:32 -0700846 const void *val;
YOSHIFUJI Hideakic9eaf172007-02-09 23:24:38 +0900847
Arnaldo Carvalho de Melo88f964d2005-09-18 00:19:32 -0700848 switch (optname) {
849 case DCCP_SOCKOPT_CCID_RX_INFO:
Gerrit Renker8e138e72007-12-17 10:07:44 -0200850 if (len < sizeof(rx_info))
Arnaldo Carvalho de Melo88f964d2005-09-18 00:19:32 -0700851 return -EINVAL;
Gerrit Renker996ccf42009-10-05 00:53:13 +0000852 rx_info.tfrcrx_x_recv = hc->rx_x_recv;
853 rx_info.tfrcrx_rtt = hc->rx_rtt;
854 rx_info.tfrcrx_p = hc->rx_pinv == 0 ? ~0U :
855 scaled_div(1, hc->rx_pinv);
Gerrit Renker8e138e72007-12-17 10:07:44 -0200856 len = sizeof(rx_info);
857 val = &rx_info;
Arnaldo Carvalho de Melo88f964d2005-09-18 00:19:32 -0700858 break;
859 default:
860 return -ENOPROTOOPT;
861 }
862
863 if (put_user(len, optlen) || copy_to_user(optval, val, len))
864 return -EFAULT;
865
866 return 0;
867}
868
Gerrit Renkerddebc972009-01-04 21:42:53 -0800869struct ccid_operations ccid3_ops = {
Ian McDonald3dd9a7c2006-09-22 14:26:44 +1200870 .ccid_id = DCCPC_CCID3,
Gerrit Renker84a97b02007-12-13 23:33:25 -0200871 .ccid_name = "TCP-Friendly Rate Control",
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800872 .ccid_hc_tx_obj_size = sizeof(struct ccid3_hc_tx_sock),
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700873 .ccid_hc_tx_init = ccid3_hc_tx_init,
874 .ccid_hc_tx_exit = ccid3_hc_tx_exit,
875 .ccid_hc_tx_send_packet = ccid3_hc_tx_send_packet,
876 .ccid_hc_tx_packet_sent = ccid3_hc_tx_packet_sent,
877 .ccid_hc_tx_packet_recv = ccid3_hc_tx_packet_recv,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700878 .ccid_hc_tx_parse_options = ccid3_hc_tx_parse_options,
Arnaldo Carvalho de Melo91f0ebf2006-03-20 19:21:44 -0800879 .ccid_hc_rx_obj_size = sizeof(struct ccid3_hc_rx_sock),
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700880 .ccid_hc_rx_init = ccid3_hc_rx_init,
881 .ccid_hc_rx_exit = ccid3_hc_rx_exit,
882 .ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options,
883 .ccid_hc_rx_packet_recv = ccid3_hc_rx_packet_recv,
Arnaldo Carvalho de Melo2babe1f2005-08-23 21:52:35 -0700884 .ccid_hc_rx_get_info = ccid3_hc_rx_get_info,
885 .ccid_hc_tx_get_info = ccid3_hc_tx_get_info,
Arnaldo Carvalho de Melo88f964d2005-09-18 00:19:32 -0700886 .ccid_hc_rx_getsockopt = ccid3_hc_rx_getsockopt,
887 .ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt,
Arnaldo Carvalho de Melo7c657872005-08-09 20:14:34 -0700888};
Arnaldo Carvalho de Melo8109b022006-12-10 16:01:18 -0200889
Gerrit Renker56724aa2006-11-20 18:28:09 -0200890#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
Gerrit Renker43264992008-08-23 13:28:27 +0200891module_param(ccid3_debug, bool, 0644);
Gerrit Renkerddebc972009-01-04 21:42:53 -0800892MODULE_PARM_DESC(ccid3_debug, "Enable CCID-3 debug messages");
Gerrit Renker56724aa2006-11-20 18:28:09 -0200893#endif