net: cleanup unsigned to unsigned int
[linux-2.6-block.git] / net / dccp / ccids / ccid3.c
CommitLineData
7c657876 1/*
954c2db8 2 * Copyright (c) 2007 The University of Aberdeen, Scotland, UK
b2f41ff4
IM
3 * Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
4 * Copyright (c) 2005-7 Ian McDonald <ian.mcdonald@jandi.co.nz>
7c657876
ACM
5 *
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/
7c657876
ACM
10 *
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 */
7c657876
ACM
35#include "../dccp.h"
36#include "ccid3.h"
37
76fd1e87
GR
38#include <asm/unaligned.h>
39
56724aa4 40#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
eb939922 41static bool ccid3_debug;
56724aa4 42#define ccid3_pr_debug(format, a...) DCCP_PR_DEBUG(ccid3_debug, format, ##a)
7c657876
ACM
43#else
44#define ccid3_pr_debug(format, a...)
45#endif
46
9bf17475
GR
47/*
48 * Transmitter Half-Connection Routines
49 */
410e27a4
GR
50#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
51static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state)
52{
36cbd3dc 53 static const char *const ccid3_state_names[] = {
410e27a4
GR
54 [TFRC_SSTATE_NO_SENT] = "NO_SENT",
55 [TFRC_SSTATE_NO_FBACK] = "NO_FBACK",
56 [TFRC_SSTATE_FBACK] = "FBACK",
410e27a4
GR
57 };
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{
996ccf49
GR
66 struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
67 enum ccid3_hc_tx_states oldstate = hc->tx_state;
410e27a4
GR
68
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);
996ccf49 73 hc->tx_state = state;
410e27a4 74}
7c657876 75
a21f9f96 76/*
6c08b2cf
GR
77 * Compute the initial sending rate X_init in the manner of RFC 3390:
78 *
410e27a4 79 * X_init = min(4 * s, max(2 * s, 4380 bytes)) / RTT
6c08b2cf 80 *
410e27a4
GR
81 * 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.
a21f9f96
GR
83 * 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{
996ccf49
GR
87 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);
a21f9f96 89
996ccf49 90 return scaled_div(w_init << 6, hc->tx_rtt);
a21f9f96
GR
91}
92
20cbd3e1
GR
93/**
94 * ccid3_update_send_interval - Calculate new t_ipi = s / X_inst
95 * This respects the granularity of X_inst (64 * bytes/second).
17893bc1 96 */
996ccf49 97static void ccid3_update_send_interval(struct ccid3_hc_tx_sock *hc)
7c657876 98{
996ccf49 99 hc->tx_t_ipi = scaled_div32(((u64)hc->tx_s) << 6, hc->tx_x);
410e27a4 100
793734b5 101 DCCP_BUG_ON(hc->tx_t_ipi == 0);
20cbd3e1 102 ccid3_pr_debug("t_ipi=%u, s=%u, X=%u\n", hc->tx_t_ipi,
95c96174 103 hc->tx_s, (unsigned int)(hc->tx_x >> 6));
7c657876 104}
aa97efd9 105
996ccf49 106static u32 ccid3_hc_tx_idle_rtt(struct ccid3_hc_tx_sock *hc, ktime_t now)
a5358fdc 107{
996ccf49 108 u32 delta = ktime_us_delta(now, hc->tx_t_last_win_count);
a5358fdc 109
996ccf49 110 return delta / hc->tx_rtt;
a5358fdc
GR
111}
112
aa97efd9
GR
113/**
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.
5c3fbb6a 117 *
1a21e49a
GR
118 * 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 *
1a21e49a 122 */
aa97efd9 123static void ccid3_hc_tx_update_x(struct sock *sk, ktime_t *stamp)
7c657876 124{
996ccf49
GR
125 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;
52515e77 128 ktime_t now = stamp ? *stamp : ktime_get_real();
7c657876 129
0c150efb
GR
130 /*
131 * Handle IDLE periods: do not reduce below RFC3390 initial sending rate
a5358fdc
GR
132 * 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.
0c150efb
GR
134 * For consistency with X and X_recv, min_rate is also scaled by 2^6.
135 */
996ccf49 136 if (ccid3_hc_tx_idle_rtt(hc, now) >= 2) {
0c150efb 137 min_rate = rfc3390_initial_rate(sk);
996ccf49 138 min_rate = max(min_rate, 2 * hc->tx_x_recv);
0c150efb
GR
139 }
140
996ccf49 141 if (hc->tx_p > 0) {
1a21e49a 142
996ccf49
GR
143 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);
a79ef76f 145
996ccf49 146 } else if (ktime_us_delta(now, hc->tx_t_ld) - (s64)hc->tx_rtt >= 0) {
ac198ea8 147
996ccf49
GR
148 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;
ff586298 152 }
b6ee3d4a 153
996ccf49 154 if (hc->tx_x != old_x) {
1761f7d7 155 ccid3_pr_debug("X_prev=%u, X_now=%u, X_calc=%u, "
95c96174
ED
156 "X_recv=%u\n", (unsigned int)(old_x >> 6),
157 (unsigned int)(hc->tx_x >> 6), hc->tx_x_calc,
158 (unsigned int)(hc->tx_x_recv >> 6));
8699be7d 159
996ccf49 160 ccid3_update_send_interval(hc);
8699be7d 161 }
7c657876
ACM
162}
163
78ad713d 164/*
410e27a4
GR
165 * Track the mean packet size `s' (cf. RFC 4342, 5.3 and RFC 3448, 4.1)
166 * @len: DCCP packet payload size in bytes
78ad713d 167 */
996ccf49 168static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hc, int len)
78ad713d 169{
996ccf49 170 const u16 old_s = hc->tx_s;
410e27a4 171
996ccf49 172 hc->tx_s = tfrc_ewma(hc->tx_s, len, 9);
410e27a4 173
996ccf49
GR
174 if (hc->tx_s != old_s)
175 ccid3_update_send_interval(hc);
78ad713d
GR
176}
177
9f8681db 178/*
8109b02b 179 * Update Window Counter using the algorithm from [RFC 4342, 8.1].
825de27d 180 * As elsewhere, RTT > 0 is assumed by using dccp_sample_rtt().
9f8681db 181 */
996ccf49 182static inline void ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock *hc,
8132da4d 183 ktime_t now)
9f8681db 184{
996ccf49
GR
185 u32 delta = ktime_us_delta(now, hc->tx_t_last_win_count),
186 quarter_rtts = (4 * delta) / hc->tx_rtt;
9f8681db
GR
187
188 if (quarter_rtts > 0) {
996ccf49
GR
189 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 */
9f8681db
GR
192 }
193}
194
7c657876
ACM
195static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
196{
197 struct sock *sk = (struct sock *)data;
996ccf49 198 struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
2a1fda6f 199 unsigned long t_nfb = USEC_PER_SEC / 5;
7c657876
ACM
200
201 bh_lock_sock(sk);
202 if (sock_owned_by_user(sk)) {
203 /* Try again later. */
204 /* XXX: set some sensible MIB */
48e03eee 205 goto restart_timer;
7c657876
ACM
206 }
207
b1383380 208 ccid3_pr_debug("%s(%p, state=%s) - entry\n", dccp_role(sk), sk,
996ccf49 209 ccid3_tx_state_name(hc->tx_state));
a9672411 210
80763dfb
GR
211 /* Ignore and do not restart after leaving the established state */
212 if ((1 << sk->sk_state) & ~(DCCPF_OPEN | DCCPF_PARTOPEN))
213 goto out;
214
215 /* Reset feedback state to "no feedback received" */
996ccf49 216 if (hc->tx_state == TFRC_SSTATE_FBACK)
410e27a4 217 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
d0995e6a 218
52515e77
GR
219 /*
220 * Determine new allowed sending rate X as per draft rfc3448bis-00, 4.4
67b67e36 221 * RTO is 0 if and only if no feedback has been received yet.
52515e77 222 */
67b67e36 223 if (hc->tx_t_rto == 0 || hc->tx_p == 0) {
52515e77
GR
224
225 /* halve send rate directly */
996ccf49
GR
226 hc->tx_x = max(hc->tx_x / 2,
227 (((__u64)hc->tx_s) << 6) / TFRC_T_MBI);
228 ccid3_update_send_interval(hc);
52515e77 229 } else {
1f2333ae 230 /*
52515e77 231 * Modify the cached value of X_recv
0c150efb 232 *
52515e77 233 * If (X_calc > 2 * X_recv)
0c150efb
GR
234 * X_recv = max(X_recv / 2, s / (2 * t_mbi));
235 * Else
236 * X_recv = X_calc / 4;
237 *
238 * Note that X_recv is scaled by 2^6 while X_calc is not
1f2333ae 239 */
996ccf49
GR
240 if (hc->tx_x_calc > (hc->tx_x_recv >> 5))
241 hc->tx_x_recv =
242 max(hc->tx_x_recv / 2,
243 (((__u64)hc->tx_s) << 6) / (2*TFRC_T_MBI));
52515e77 244 else {
996ccf49
GR
245 hc->tx_x_recv = hc->tx_x_calc;
246 hc->tx_x_recv <<= 4;
7c657876 247 }
aa97efd9 248 ccid3_hc_tx_update_x(sk, NULL);
7c657876 249 }
52515e77 250 ccid3_pr_debug("Reduced X to %llu/64 bytes/sec\n",
996ccf49 251 (unsigned long long)hc->tx_x);
52515e77
GR
252
253 /*
254 * Set new timeout for the nofeedback timer.
255 * See comments in packet_recv() regarding the value of t_RTO.
256 */
67b67e36 257 if (unlikely(hc->tx_t_rto == 0)) /* no feedback received yet */
52515e77
GR
258 t_nfb = TFRC_INITIAL_TIMEOUT;
259 else
996ccf49 260 t_nfb = max(hc->tx_t_rto, 2 * hc->tx_t_ipi);
7c657876 261
48e03eee 262restart_timer:
996ccf49 263 sk_reset_timer(sk, &hc->tx_no_feedback_timer,
c9eaf173 264 jiffies + usecs_to_jiffies(t_nfb));
7c657876
ACM
265out:
266 bh_unlock_sock(sk);
267 sock_put(sk);
268}
269
fe84f414
GR
270/**
271 * ccid3_hc_tx_send_packet - Delay-based dequeueing of TX packets
272 * @skb: next packet candidate to send on @sk
273 * This function uses the convention of ccid_packet_dequeue_eval() and
274 * returns a millisecond-delay value between 0 and t_mbi = 64000 msec.
7da7f456 275 */
6b57c93d 276static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
7c657876
ACM
277{
278 struct dccp_sock *dp = dccp_sk(sk);
996ccf49 279 struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
8132da4d
GR
280 ktime_t now = ktime_get_real();
281 s64 delay;
7c657876 282
7c657876 283 /*
da335baf
GR
284 * This function is called only for Data and DataAck packets. Sending
285 * zero-sized Data(Ack)s is theoretically possible, but for congestion
286 * control this case is pathological - ignore it.
7c657876 287 */
6b57c93d 288 if (unlikely(skb->len == 0))
da335baf 289 return -EBADMSG;
7c657876 290
80763dfb 291 if (hc->tx_state == TFRC_SSTATE_NO_SENT) {
996ccf49
GR
292 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;
90feeb95
GR
296
297 /* Set t_0 for initial packet */
996ccf49 298 hc->tx_t_nom = now;
410e27a4 299
996ccf49 300 hc->tx_s = skb->len;
30833ffe 301
30833ffe
GR
302 /*
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);
996ccf49
GR
309 hc->tx_rtt = dp->dccps_syn_rtt;
310 hc->tx_x = rfc3390_initial_rate(sk);
311 hc->tx_t_ld = now;
30833ffe 312 } else {
3294f202
GR
313 /*
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 */
996ccf49
GR
319 hc->tx_rtt = DCCP_FALLBACK_RTT;
320 hc->tx_x = hc->tx_s;
321 hc->tx_x <<= 6;
30833ffe 322 }
996ccf49 323 ccid3_update_send_interval(hc);
30833ffe 324
410e27a4 325 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
80763dfb
GR
326
327 } else {
996ccf49 328 delay = ktime_us_delta(hc->tx_t_nom, now);
8699be7d 329 ccid3_pr_debug("delay=%ld\n", (long)delay);
91cf5a17 330 /*
20cbd3e1 331 * Scheduling of packet transmissions (RFC 5348, 8.3)
91cf5a17
GR
332 *
333 * if (t_now > t_nom - delta)
334 * // send the packet now
335 * else
336 * // send the packet in (t_nom - t_now) milliseconds.
337 */
20cbd3e1
GR
338 if (delay >= TFRC_T_DELTA)
339 return (u32)delay / USEC_PER_MSEC;
9f8681db 340
996ccf49 341 ccid3_hc_tx_update_win_count(hc, now);
7c657876
ACM
342 }
343
7da7f456
GR
344 /* prepare to send now (add options etc.) */
345 dp->dccps_hc_tx_insert_options = 1;
996ccf49 346 DCCP_SKB_CB(skb)->dccpd_ccval = hc->tx_last_win_count;
e312d100
GR
347
348 /* set the nominal send time for the next following packet */
996ccf49 349 hc->tx_t_nom = ktime_add_us(hc->tx_t_nom, hc->tx_t_ipi);
fe84f414 350 return CCID_PACKET_SEND_AT_ONCE;
7c657876
ACM
351}
352
baf9e782 353static void ccid3_hc_tx_packet_sent(struct sock *sk, unsigned int len)
7c657876 354{
996ccf49 355 struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
7c657876 356
996ccf49 357 ccid3_hc_tx_update_s(hc, len);
7c657876 358
996ccf49 359 if (tfrc_tx_hist_add(&hc->tx_hist, dccp_sk(sk)->dccps_gss))
c5a1ae9a 360 DCCP_CRIT("packet history - out of memory!");
7c657876
ACM
361}
362
363static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
364{
996ccf49 365 struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
d2c72630 366 struct tfrc_tx_hist_entry *acked;
0740d49c 367 ktime_t now;
2a1fda6f 368 unsigned long t_nfb;
536bb20b 369 u32 r_sample;
1f2333ae 370
7c657876
ACM
371 /* we are only interested in ACKs */
372 if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
373 DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
374 return;
d2c72630
GR
375 /*
376 * Locate the acknowledged packet in the TX history.
377 *
378 * Returning "entry not found" here can for instance happen when
379 * - the host has not sent out anything (e.g. a passive server),
380 * - the Ack is outdated (packet with higher Ack number was received),
381 * - it is a bogus Ack (for a packet not sent on this connection).
382 */
383 acked = tfrc_tx_hist_find_entry(hc->tx_hist, dccp_hdr_ack_seq(skb));
384 if (acked == NULL)
5bd370a6 385 return;
d2c72630
GR
386 /* For the sake of RTT sampling, ignore/remove all older entries */
387 tfrc_tx_hist_purge(&acked->next);
388
389 /* Update the moving average for the RTT estimate (RFC 3448, 4.3) */
390 now = ktime_get_real();
391 r_sample = dccp_sample_rtt(sk, ktime_us_delta(now, acked->stamp));
392 hc->tx_rtt = tfrc_ewma(hc->tx_rtt, r_sample, 9);
63b3a73b 393
d8d1252f
GR
394 /*
395 * Update allowed sending rate X as per draft rfc3448bis-00, 4.2/3
396 */
996ccf49 397 if (hc->tx_state == TFRC_SSTATE_NO_FBACK) {
410e27a4 398 ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
5c3fbb6a 399
996ccf49 400 if (hc->tx_t_rto == 0) {
d8d1252f
GR
401 /*
402 * Initial feedback packet: Larger Initial Windows (4.2)
403 */
996ccf49
GR
404 hc->tx_x = rfc3390_initial_rate(sk);
405 hc->tx_t_ld = now;
a79ef76f 406
996ccf49 407 ccid3_update_send_interval(hc);
7c657876 408
d8d1252f 409 goto done_computing_x;
996ccf49 410 } else if (hc->tx_p == 0) {
d8d1252f
GR
411 /*
412 * First feedback after nofeedback timer expiry (4.3)
413 */
414 goto done_computing_x;
415 }
416 }
7c657876 417
d8d1252f 418 /* Update sending rate (step 4 of [RFC 3448, 4.3]) */
996ccf49
GR
419 if (hc->tx_p > 0)
420 hc->tx_x_calc = tfrc_calc_x(hc->tx_s, hc->tx_rtt, hc->tx_p);
d8d1252f 421 ccid3_hc_tx_update_x(sk, &now);
7c657876 422
d8d1252f
GR
423done_computing_x:
424 ccid3_pr_debug("%s(%p), RTT=%uus (sample=%uus), s=%u, "
5bd370a6 425 "p=%u, X_calc=%u, X_recv=%u, X=%u\n",
996ccf49
GR
426 dccp_role(sk), sk, hc->tx_rtt, r_sample,
427 hc->tx_s, hc->tx_p, hc->tx_x_calc,
95c96174
ED
428 (unsigned int)(hc->tx_x_recv >> 6),
429 (unsigned int)(hc->tx_x >> 6));
7c657876 430
5bd370a6 431 /* unschedule no feedback timer */
996ccf49 432 sk_stop_timer(sk, &hc->tx_no_feedback_timer);
7c657876 433
5bd370a6
GR
434 /*
435 * As we have calculated new ipi, delta, t_nom it is possible
436 * that we now can send a packet, so wake up dccp_wait_for_ccid
437 */
438 sk->sk_write_space(sk);
8c60f3fa 439
5bd370a6 440 /*
89858ad1
GR
441 * Update timeout interval for the nofeedback timer. In order to control
442 * rate halving on networks with very low RTTs (<= 1 ms), use per-route
443 * tunable RTAX_RTO_MIN value as the lower bound.
5bd370a6 444 */
89858ad1
GR
445 hc->tx_t_rto = max_t(u32, 4 * hc->tx_rtt,
446 USEC_PER_SEC/HZ * tcp_rto_min(sk));
5bd370a6
GR
447 /*
448 * Schedule no feedback timer to expire in
449 * max(t_RTO, 2 * s/X) = max(t_RTO, 2 * t_ipi)
450 */
996ccf49 451 t_nfb = max(hc->tx_t_rto, 2 * hc->tx_t_ipi);
7c657876 452
5bd370a6
GR
453 ccid3_pr_debug("%s(%p), Scheduled no feedback timer to "
454 "expire in %lu jiffies (%luus)\n",
388d5e99 455 dccp_role(sk), sk, usecs_to_jiffies(t_nfb), t_nfb);
a9672411 456
996ccf49 457 sk_reset_timer(sk, &hc->tx_no_feedback_timer,
5bd370a6 458 jiffies + usecs_to_jiffies(t_nfb));
7c657876
ACM
459}
460
4874c131
GR
461static int ccid3_hc_tx_parse_options(struct sock *sk, u8 packet_type,
462 u8 option, u8 *optval, u8 optlen)
7c657876 463{
996ccf49 464 struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
76fd1e87 465 __be32 opt_val;
7c657876 466
410e27a4 467 switch (option) {
37efb03f 468 case TFRC_OPT_RECEIVE_RATE:
410e27a4 469 case TFRC_OPT_LOSS_EVENT_RATE:
4874c131
GR
470 /* Must be ignored on Data packets, cf. RFC 4342 8.3 and 8.5 */
471 if (packet_type == DCCP_PKT_DATA)
472 break;
473 if (unlikely(optlen != 4)) {
37efb03f 474 DCCP_WARN("%s(%p), invalid len %d for %u\n",
4874c131 475 dccp_role(sk), sk, optlen, option);
37efb03f 476 return -EINVAL;
7c657876 477 }
4874c131 478 opt_val = ntohl(get_unaligned((__be32 *)optval));
37efb03f
GR
479
480 if (option == TFRC_OPT_RECEIVE_RATE) {
536bb20b
GR
481 /* Receive Rate is kept in units of 64 bytes/second */
482 hc->tx_x_recv = opt_val;
483 hc->tx_x_recv <<= 6;
484
410e27a4 485 ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n",
37efb03f
GR
486 dccp_role(sk), sk, opt_val);
487 } else {
536bb20b
GR
488 /* Update the fixpoint Loss Event Rate fraction */
489 hc->tx_p = tfrc_invert_loss_event_rate(opt_val);
490
37efb03f
GR
491 ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n",
492 dccp_role(sk), sk, opt_val);
410e27a4 493 }
7c657876 494 }
37efb03f 495 return 0;
7c657876
ACM
496}
497
91f0ebf7 498static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
7c657876 499{
996ccf49 500 struct ccid3_hc_tx_sock *hc = ccid_priv(ccid);
7c657876 501
996ccf49
GR
502 hc->tx_state = TFRC_SSTATE_NO_SENT;
503 hc->tx_hist = NULL;
504 setup_timer(&hc->tx_no_feedback_timer,
410e27a4 505 ccid3_hc_tx_no_feedback_timer, (unsigned long)sk);
7c657876
ACM
506 return 0;
507}
508
509static void ccid3_hc_tx_exit(struct sock *sk)
510{
996ccf49 511 struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
7c657876 512
996ccf49 513 sk_stop_timer(sk, &hc->tx_no_feedback_timer);
996ccf49 514 tfrc_tx_hist_purge(&hc->tx_hist);
7c657876
ACM
515}
516
9bf17475
GR
517static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info)
518{
51c22bb5
GR
519 info->tcpi_rto = ccid3_hc_tx_sk(sk)->tx_t_rto;
520 info->tcpi_rtt = ccid3_hc_tx_sk(sk)->tx_rtt;
9bf17475
GR
521}
522
523static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
524 u32 __user *optval, int __user *optlen)
525{
51c22bb5 526 const struct ccid3_hc_tx_sock *hc = ccid3_hc_tx_sk(sk);
67b67e36 527 struct tfrc_tx_info tfrc;
9bf17475
GR
528 const void *val;
529
9bf17475
GR
530 switch (optname) {
531 case DCCP_SOCKOPT_CCID_TX_INFO:
67b67e36 532 if (len < sizeof(tfrc))
9bf17475 533 return -EINVAL;
67b67e36
GR
534 tfrc.tfrctx_x = hc->tx_x;
535 tfrc.tfrctx_x_recv = hc->tx_x_recv;
536 tfrc.tfrctx_x_calc = hc->tx_x_calc;
537 tfrc.tfrctx_rtt = hc->tx_rtt;
538 tfrc.tfrctx_p = hc->tx_p;
539 tfrc.tfrctx_rto = hc->tx_t_rto;
540 tfrc.tfrctx_ipi = hc->tx_t_ipi;
541 len = sizeof(tfrc);
542 val = &tfrc;
9bf17475
GR
543 break;
544 default:
545 return -ENOPROTOOPT;
546 }
547
548 if (put_user(len, optlen) || copy_to_user(optval, val, len))
549 return -EFAULT;
550
551 return 0;
552}
553
7c657876 554/*
9bf17475 555 * Receiver Half-Connection Routines
7c657876 556 */
410e27a4
GR
557
558/* CCID3 feedback types */
559enum ccid3_fback_type {
560 CCID3_FBACK_NONE = 0,
561 CCID3_FBACK_INITIAL,
562 CCID3_FBACK_PERIODIC,
563 CCID3_FBACK_PARAM_CHANGE
564};
565
566#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
567static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
568{
36cbd3dc 569 static const char *const ccid3_rx_state_names[] = {
410e27a4
GR
570 [TFRC_RSTATE_NO_DATA] = "NO_DATA",
571 [TFRC_RSTATE_DATA] = "DATA",
410e27a4
GR
572 };
573
574 return ccid3_rx_state_names[state];
575}
576#endif
577
578static void ccid3_hc_rx_set_state(struct sock *sk,
579 enum ccid3_hc_rx_states state)
580{
996ccf49
GR
581 struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
582 enum ccid3_hc_rx_states oldstate = hc->rx_state;
410e27a4
GR
583
584 ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
585 dccp_role(sk), sk, ccid3_rx_state_name(oldstate),
586 ccid3_rx_state_name(state));
587 WARN_ON(state == oldstate);
996ccf49 588 hc->rx_state = state;
410e27a4
GR
589}
590
b84a2189
ACM
591static void ccid3_hc_rx_send_feedback(struct sock *sk,
592 const struct sk_buff *skb,
593 enum ccid3_fback_type fbtype)
7c657876 594{
996ccf49 595 struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
410e27a4 596 struct dccp_sock *dp = dccp_sk(sk);
80763dfb 597 ktime_t now = ktime_get_real();
410e27a4
GR
598 s64 delta = 0;
599
b84a2189
ACM
600 switch (fbtype) {
601 case CCID3_FBACK_INITIAL:
996ccf49
GR
602 hc->rx_x_recv = 0;
603 hc->rx_pinv = ~0U; /* see RFC 4342, 8.5 */
7c657876 604 break;
b84a2189
ACM
605 case CCID3_FBACK_PARAM_CHANGE:
606 /*
607 * When parameters change (new loss or p > p_prev), we do not
608 * have a reliable estimate for R_m of [RFC 3448, 6.2] and so
410e27a4
GR
609 * need to reuse the previous value of X_recv. However, when
610 * X_recv was 0 (due to early loss), this would kill X down to
611 * s/t_mbi (i.e. one packet in 64 seconds).
612 * To avoid such drastic reduction, we approximate X_recv as
613 * the number of bytes since last feedback.
614 * This is a safe fallback, since X is bounded above by X_calc.
b84a2189 615 */
996ccf49 616 if (hc->rx_x_recv > 0)
410e27a4
GR
617 break;
618 /* fall through */
b84a2189 619 case CCID3_FBACK_PERIODIC:
996ccf49 620 delta = ktime_us_delta(now, hc->rx_tstamp_last_feedback);
410e27a4
GR
621 if (delta <= 0)
622 DCCP_BUG("delta (%ld) <= 0", (long)delta);
623 else
996ccf49 624 hc->rx_x_recv = scaled_div32(hc->rx_bytes_recv, delta);
7c657876 625 break;
b84a2189 626 default:
7c657876
ACM
627 return;
628 }
629
410e27a4 630 ccid3_pr_debug("Interval %ldusec, X_recv=%u, 1/p=%u\n", (long)delta,
996ccf49 631 hc->rx_x_recv, hc->rx_pinv);
7c657876 632
996ccf49
GR
633 hc->rx_tstamp_last_feedback = now;
634 hc->rx_last_counter = dccp_hdr(skb)->dccph_ccval;
635 hc->rx_bytes_recv = 0;
68c89ee5 636
410e27a4
GR
637 dp->dccps_hc_rx_insert_options = 1;
638 dccp_send_ack(sk);
7c657876
ACM
639}
640
2d0817d1 641static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
7c657876 642{
51c22bb5 643 const struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
60fe62e7 644 __be32 x_recv, pinv;
7c657876 645
59d203f9 646 if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
2d0817d1 647 return 0;
7c657876 648
4fded33b 649 if (dccp_packet_without_ack(skb))
2d0817d1
ACM
650 return 0;
651
996ccf49
GR
652 x_recv = htonl(hc->rx_x_recv);
653 pinv = htonl(hc->rx_pinv);
2d0817d1 654
a7d13fbf 655 if (dccp_insert_option(skb, TFRC_OPT_LOSS_EVENT_RATE,
8109b02b 656 &pinv, sizeof(pinv)) ||
a7d13fbf 657 dccp_insert_option(skb, TFRC_OPT_RECEIVE_RATE,
8109b02b 658 &x_recv, sizeof(x_recv)))
2d0817d1
ACM
659 return -1;
660
661 return 0;
7c657876
ACM
662}
663
aa1b1ff0
GR
664/**
665 * ccid3_first_li - Implements [RFC 5348, 6.3.1]
954c2db8
GR
666 *
667 * Determine the length of the first loss interval via inverse lookup.
668 * Assume that X_recv can be computed by the throughput equation
669 * s
670 * X_recv = --------
671 * R * fval
672 * Find some p such that f(p) = fval; return 1/p (scaled).
673 */
674static u32 ccid3_first_li(struct sock *sk)
675{
996ccf49 676 struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
410e27a4 677 u32 x_recv, p, delta;
954c2db8
GR
678 u64 fval;
679
996ccf49 680 if (hc->rx_rtt == 0) {
410e27a4 681 DCCP_WARN("No RTT estimate available, using fallback RTT\n");
996ccf49 682 hc->rx_rtt = DCCP_FALLBACK_RTT;
410e27a4 683 }
d20ed95f 684
996ccf49
GR
685 delta = ktime_to_us(net_timedelta(hc->rx_tstamp_last_feedback));
686 x_recv = scaled_div32(hc->rx_bytes_recv, delta);
410e27a4
GR
687 if (x_recv == 0) { /* would also trigger divide-by-zero */
688 DCCP_WARN("X_recv==0\n");
67b67e36 689 if (hc->rx_x_recv == 0) {
410e27a4
GR
690 DCCP_BUG("stored value of X_recv is zero");
691 return ~0U;
692 }
67b67e36 693 x_recv = hc->rx_x_recv;
410e27a4 694 }
954c2db8 695
996ccf49 696 fval = scaled_div(hc->rx_s, hc->rx_rtt);
410e27a4 697 fval = scaled_div32(fval, x_recv);
954c2db8
GR
698 p = tfrc_calc_x_reverse_lookup(fval);
699
700 ccid3_pr_debug("%s(%p), receive rate=%u bytes/s, implied "
701 "loss rate=%u\n", dccp_role(sk), sk, x_recv, p);
702
410e27a4 703 return p == 0 ? ~0U : scaled_div(1, p);
954c2db8
GR
704}
705
b84a2189 706static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
7c657876 707{
996ccf49 708 struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
410e27a4 709 enum ccid3_fback_type do_feedback = CCID3_FBACK_NONE;
5b5d0e70 710 const u64 ndp = dccp_sk(sk)->dccps_options_received.dccpor_ndp;
b84a2189
ACM
711 const bool is_data_packet = dccp_data_packet(skb);
712
996ccf49 713 if (unlikely(hc->rx_state == TFRC_RSTATE_NO_DATA)) {
410e27a4
GR
714 if (is_data_packet) {
715 const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4;
716 do_feedback = CCID3_FBACK_INITIAL;
717 ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA);
996ccf49 718 hc->rx_s = payload;
410e27a4 719 /*
388d5e99 720 * Not necessary to update rx_bytes_recv here,
410e27a4
GR
721 * since X_recv = 0 for the first feedback packet (cf.
722 * RFC 3448, 6.3) -- gerrit
723 */
724 }
725 goto update_records;
726 }
727
996ccf49 728 if (tfrc_rx_hist_duplicate(&hc->rx_hist, skb))
410e27a4
GR
729 return; /* done receiving */
730
731 if (is_data_packet) {
732 const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4;
733 /*
734 * Update moving-average of s and the sum of received payload bytes
735 */
996ccf49
GR
736 hc->rx_s = tfrc_ewma(hc->rx_s, payload, 9);
737 hc->rx_bytes_recv += payload;
410e27a4
GR
738 }
739
d20ed95f
GR
740 /*
741 * Perform loss detection and handle pending losses
742 */
996ccf49 743 if (tfrc_rx_handle_loss(&hc->rx_hist, &hc->rx_li_hist,
410e27a4
GR
744 skb, ndp, ccid3_first_li, sk)) {
745 do_feedback = CCID3_FBACK_PARAM_CHANGE;
746 goto done_receiving;
747 }
748
996ccf49 749 if (tfrc_rx_hist_loss_pending(&hc->rx_hist))
410e27a4
GR
750 return; /* done receiving */
751
88e97a93 752 /*
410e27a4 753 * Handle data packets: RTT sampling and monitoring p
88e97a93 754 */
410e27a4
GR
755 if (unlikely(!is_data_packet))
756 goto update_records;
757
996ccf49
GR
758 if (!tfrc_lh_is_initialised(&hc->rx_li_hist)) {
759 const u32 sample = tfrc_rx_hist_sample_rtt(&hc->rx_hist, skb);
410e27a4
GR
760 /*
761 * Empty loss history: no loss so far, hence p stays 0.
762 * Sample RTT values, since an RTT estimate is required for the
763 * computation of p when the first loss occurs; RFC 3448, 6.3.1.
764 */
765 if (sample != 0)
996ccf49 766 hc->rx_rtt = tfrc_ewma(hc->rx_rtt, sample, 9);
410e27a4 767
996ccf49 768 } else if (tfrc_lh_update_i_mean(&hc->rx_li_hist, skb)) {
410e27a4
GR
769 /*
770 * Step (3) of [RFC 3448, 6.1]: Recompute I_mean and, if I_mean
771 * has decreased (resp. p has increased), send feedback now.
772 */
773 do_feedback = CCID3_FBACK_PARAM_CHANGE;
774 }
775
b84a2189
ACM
776 /*
777 * Check if the periodic once-per-RTT feedback is due; RFC 4342, 10.3
778 */
996ccf49 779 if (SUB16(dccp_hdr(skb)->dccph_ccval, hc->rx_last_counter) > 3)
410e27a4
GR
780 do_feedback = CCID3_FBACK_PERIODIC;
781
782update_records:
996ccf49 783 tfrc_rx_hist_add_packet(&hc->rx_hist, skb, ndp);
410e27a4
GR
784
785done_receiving:
786 if (do_feedback)
787 ccid3_hc_rx_send_feedback(sk, skb, do_feedback);
7c657876
ACM
788}
789
91f0ebf7 790static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
7c657876 791{
996ccf49 792 struct ccid3_hc_rx_sock *hc = ccid_priv(ccid);
7c657876 793
996ccf49
GR
794 hc->rx_state = TFRC_RSTATE_NO_DATA;
795 tfrc_lh_init(&hc->rx_li_hist);
796 return tfrc_rx_hist_alloc(&hc->rx_hist);
7c657876
ACM
797}
798
799static void ccid3_hc_rx_exit(struct sock *sk)
800{
996ccf49 801 struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
7c657876 802
996ccf49
GR
803 tfrc_rx_hist_purge(&hc->rx_hist);
804 tfrc_lh_cleanup(&hc->rx_li_hist);
7c657876
ACM
805}
806
2babe1f6
ACM
807static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
808{
51c22bb5 809 info->tcpi_ca_state = ccid3_hc_rx_sk(sk)->rx_state;
8109b02b 810 info->tcpi_options |= TCPI_OPT_TIMESTAMPS;
51c22bb5 811 info->tcpi_rcv_rtt = ccid3_hc_rx_sk(sk)->rx_rtt;
2babe1f6
ACM
812}
813
88f964db
ACM
814static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len,
815 u32 __user *optval, int __user *optlen)
816{
51c22bb5 817 const struct ccid3_hc_rx_sock *hc = ccid3_hc_rx_sk(sk);
8e138e79 818 struct tfrc_rx_info rx_info;
88f964db 819 const void *val;
c9eaf173 820
88f964db
ACM
821 switch (optname) {
822 case DCCP_SOCKOPT_CCID_RX_INFO:
8e138e79 823 if (len < sizeof(rx_info))
88f964db 824 return -EINVAL;
996ccf49
GR
825 rx_info.tfrcrx_x_recv = hc->rx_x_recv;
826 rx_info.tfrcrx_rtt = hc->rx_rtt;
792e6d33 827 rx_info.tfrcrx_p = tfrc_invert_loss_event_rate(hc->rx_pinv);
8e138e79
GR
828 len = sizeof(rx_info);
829 val = &rx_info;
88f964db
ACM
830 break;
831 default:
832 return -ENOPROTOOPT;
833 }
834
835 if (put_user(len, optlen) || copy_to_user(optval, val, len))
836 return -EFAULT;
837
838 return 0;
839}
840
ddebc973 841struct ccid_operations ccid3_ops = {
3dd9a7c3 842 .ccid_id = DCCPC_CCID3,
84a97b0a 843 .ccid_name = "TCP-Friendly Rate Control",
91f0ebf7 844 .ccid_hc_tx_obj_size = sizeof(struct ccid3_hc_tx_sock),
7c657876
ACM
845 .ccid_hc_tx_init = ccid3_hc_tx_init,
846 .ccid_hc_tx_exit = ccid3_hc_tx_exit,
847 .ccid_hc_tx_send_packet = ccid3_hc_tx_send_packet,
848 .ccid_hc_tx_packet_sent = ccid3_hc_tx_packet_sent,
849 .ccid_hc_tx_packet_recv = ccid3_hc_tx_packet_recv,
7c657876 850 .ccid_hc_tx_parse_options = ccid3_hc_tx_parse_options,
91f0ebf7 851 .ccid_hc_rx_obj_size = sizeof(struct ccid3_hc_rx_sock),
7c657876
ACM
852 .ccid_hc_rx_init = ccid3_hc_rx_init,
853 .ccid_hc_rx_exit = ccid3_hc_rx_exit,
854 .ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options,
855 .ccid_hc_rx_packet_recv = ccid3_hc_rx_packet_recv,
2babe1f6
ACM
856 .ccid_hc_rx_get_info = ccid3_hc_rx_get_info,
857 .ccid_hc_tx_get_info = ccid3_hc_tx_get_info,
88f964db
ACM
858 .ccid_hc_rx_getsockopt = ccid3_hc_rx_getsockopt,
859 .ccid_hc_tx_getsockopt = ccid3_hc_tx_getsockopt,
7c657876 860};
8109b02b 861
56724aa4 862#ifdef CONFIG_IP_DCCP_CCID3_DEBUG
43264991 863module_param(ccid3_debug, bool, 0644);
ddebc973 864MODULE_PARM_DESC(ccid3_debug, "Enable CCID-3 debug messages");
56724aa4 865#endif