xref: /openbmc/linux/net/dccp/ccids/ccid3.c (revision cc0a910b942d11069d35f52b2c0ed0e229e2fb46)
1 /*
2  *  net/dccp/ccids/ccid3.c
3  *
4  *  Copyright (c) 2005-7 The University of Waikato, Hamilton, New Zealand.
5  *  Copyright (c) 2005-7 Ian McDonald <ian.mcdonald@jandi.co.nz>
6  *
7  *  An implementation of the DCCP protocol
8  *
9  *  This code has been developed by the University of Waikato WAND
10  *  research group. For further information please see http://www.wand.net.nz/
11  *
12  *  This code also uses code from Lulea University, rereleased as GPL by its
13  *  authors:
14  *  Copyright (c) 2003 Nils-Erik Mattsson, Joacim Haggmark, Magnus Erixzon
15  *
16  *  Changes to meet Linux coding standards, to make it meet latest ccid3 draft
17  *  and to make it work as a loadable module in the DCCP stack written by
18  *  Arnaldo Carvalho de Melo <acme@conectiva.com.br>.
19  *
20  *  Copyright (c) 2005 Arnaldo Carvalho de Melo <acme@conectiva.com.br>
21  *
22  *  This program is free software; you can redistribute it and/or modify
23  *  it under the terms of the GNU General Public License as published by
24  *  the Free Software Foundation; either version 2 of the License, or
25  *  (at your option) any later version.
26  *
27  *  This program is distributed in the hope that it will be useful,
28  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
29  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
30  *  GNU General Public License for more details.
31  *
32  *  You should have received a copy of the GNU General Public License
33  *  along with this program; if not, write to the Free Software
34  *  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
35  */
36 #include "../ccid.h"
37 #include "../dccp.h"
38 #include "lib/packet_history.h"
39 #include "lib/loss_interval.h"
40 #include "lib/tfrc.h"
41 #include "ccid3.h"
42 
43 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
44 static int ccid3_debug;
45 #define ccid3_pr_debug(format, a...)	DCCP_PR_DEBUG(ccid3_debug, format, ##a)
46 #else
47 #define ccid3_pr_debug(format, a...)
48 #endif
49 
50 static struct dccp_tx_hist *ccid3_tx_hist;
51 static struct dccp_rx_hist *ccid3_rx_hist;
52 static struct dccp_li_hist *ccid3_li_hist;
53 
54 /*
55  *	Transmitter Half-Connection Routines
56  */
57 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
58 static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state)
59 {
60 	static char *ccid3_state_names[] = {
61 	[TFRC_SSTATE_NO_SENT]  = "NO_SENT",
62 	[TFRC_SSTATE_NO_FBACK] = "NO_FBACK",
63 	[TFRC_SSTATE_FBACK]    = "FBACK",
64 	[TFRC_SSTATE_TERM]     = "TERM",
65 	};
66 
67 	return ccid3_state_names[state];
68 }
69 #endif
70 
71 static void ccid3_hc_tx_set_state(struct sock *sk,
72 				  enum ccid3_hc_tx_states state)
73 {
74 	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
75 	enum ccid3_hc_tx_states oldstate = hctx->ccid3hctx_state;
76 
77 	ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
78 		       dccp_role(sk), sk, ccid3_tx_state_name(oldstate),
79 		       ccid3_tx_state_name(state));
80 	WARN_ON(state == oldstate);
81 	hctx->ccid3hctx_state = state;
82 }
83 
84 /*
85  * Compute the initial sending rate X_init according to RFC 3390:
86  *	w_init   =    min(4 * MSS, max(2 * MSS, 4380 bytes))
87  *	X_init   =    w_init / RTT
88  * For consistency with other parts of the code, X_init is scaled by 2^6.
89  */
90 static inline u64 rfc3390_initial_rate(struct sock *sk)
91 {
92 	const struct dccp_sock *dp = dccp_sk(sk);
93 	const __u32 w_init = min(4 * dp->dccps_mss_cache,
94 				 max(2 * dp->dccps_mss_cache, 4380U));
95 
96 	return scaled_div(w_init << 6, ccid3_hc_tx_sk(sk)->ccid3hctx_rtt);
97 }
98 
99 /*
100  * Recalculate t_ipi and delta (should be called whenever X changes)
101  */
102 static inline void ccid3_update_send_interval(struct ccid3_hc_tx_sock *hctx)
103 {
104 	/* Calculate new t_ipi = s / X_inst (X_inst is in 64 * bytes/second) */
105 	hctx->ccid3hctx_t_ipi = scaled_div32(((u64)hctx->ccid3hctx_s) << 6,
106 					     hctx->ccid3hctx_x);
107 
108 	/* Calculate new delta by delta = min(t_ipi / 2, t_gran / 2) */
109 	hctx->ccid3hctx_delta = min_t(u32, hctx->ccid3hctx_t_ipi / 2,
110 					   TFRC_OPSYS_HALF_TIME_GRAN);
111 
112 	ccid3_pr_debug("t_ipi=%u, delta=%u, s=%u, X=%u\n",
113 		       hctx->ccid3hctx_t_ipi, hctx->ccid3hctx_delta,
114 		       hctx->ccid3hctx_s, (unsigned)(hctx->ccid3hctx_x >> 6));
115 
116 }
117 /*
118  * Update X by
119  *    If (p > 0)
120  *       X_calc = calcX(s, R, p);
121  *       X = max(min(X_calc, 2 * X_recv), s / t_mbi);
122  *    Else
123  *       If (now - tld >= R)
124  *          X = max(min(2 * X, 2 * X_recv), s / R);
125  *          tld = now;
126  *
127  * Note: X and X_recv are both stored in units of 64 * bytes/second, to support
128  *       fine-grained resolution of sending rates. This requires scaling by 2^6
129  *       throughout the code. Only X_calc is unscaled (in bytes/second).
130  *
131  */
132 static void ccid3_hc_tx_update_x(struct sock *sk, struct timeval *now)
133 
134 {
135 	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
136 	__u64 min_rate = 2 * hctx->ccid3hctx_x_recv;
137 	const  __u64 old_x = hctx->ccid3hctx_x;
138 
139 	/*
140 	 * Handle IDLE periods: do not reduce below RFC3390 initial sending rate
141 	 * when idling [RFC 4342, 5.1]. See also draft-ietf-dccp-rfc3448bis.
142 	 * For consistency with X and X_recv, min_rate is also scaled by 2^6.
143 	 */
144 	if (unlikely(hctx->ccid3hctx_idle)) {
145 		min_rate = rfc3390_initial_rate(sk);
146 		min_rate = max(min_rate, 2 * hctx->ccid3hctx_x_recv);
147 	}
148 
149 	if (hctx->ccid3hctx_p > 0) {
150 
151 		hctx->ccid3hctx_x = min(((__u64)hctx->ccid3hctx_x_calc) << 6,
152 					min_rate);
153 		hctx->ccid3hctx_x = max(hctx->ccid3hctx_x,
154 					(((__u64)hctx->ccid3hctx_s) << 6) /
155 								TFRC_T_MBI);
156 
157 	} else if (timeval_delta(now, &hctx->ccid3hctx_t_ld) -
158 			(suseconds_t)hctx->ccid3hctx_rtt >= 0) {
159 
160 		hctx->ccid3hctx_x =
161 			max(min(2 * hctx->ccid3hctx_x, min_rate),
162 			    scaled_div(((__u64)hctx->ccid3hctx_s) << 6,
163 				       hctx->ccid3hctx_rtt));
164 		hctx->ccid3hctx_t_ld = *now;
165 	}
166 
167 	if (hctx->ccid3hctx_x != old_x) {
168 		ccid3_pr_debug("X_prev=%u, X_now=%u, X_calc=%u, "
169 			       "X_recv=%u\n", (unsigned)(old_x >> 6),
170 			       (unsigned)(hctx->ccid3hctx_x >> 6),
171 			       hctx->ccid3hctx_x_calc,
172 			       (unsigned)(hctx->ccid3hctx_x_recv >> 6));
173 
174 		ccid3_update_send_interval(hctx);
175 	}
176 }
177 
178 /*
179  *	Track the mean packet size `s' (cf. RFC 4342, 5.3 and  RFC 3448, 4.1)
180  *	@len: DCCP packet payload size in bytes
181  */
182 static inline void ccid3_hc_tx_update_s(struct ccid3_hc_tx_sock *hctx, int len)
183 {
184 	const u16 old_s = hctx->ccid3hctx_s;
185 
186 	hctx->ccid3hctx_s = old_s == 0 ? len : (9 * old_s + len) / 10;
187 
188 	if (hctx->ccid3hctx_s != old_s)
189 		ccid3_update_send_interval(hctx);
190 }
191 
192 /*
193  *	Update Window Counter using the algorithm from [RFC 4342, 8.1].
194  *	The algorithm is not applicable if RTT < 4 microseconds.
195  */
196 static inline void ccid3_hc_tx_update_win_count(struct ccid3_hc_tx_sock *hctx,
197 						struct timeval *now)
198 {
199 	suseconds_t delta;
200 	u32 quarter_rtts;
201 
202 	if (unlikely(hctx->ccid3hctx_rtt < 4))	/* avoid divide-by-zero */
203 		return;
204 
205 	delta = timeval_delta(now, &hctx->ccid3hctx_t_last_win_count);
206 	DCCP_BUG_ON(delta < 0);
207 
208 	quarter_rtts = (u32)delta / (hctx->ccid3hctx_rtt / 4);
209 
210 	if (quarter_rtts > 0) {
211 		hctx->ccid3hctx_t_last_win_count = *now;
212 		hctx->ccid3hctx_last_win_count	+= min_t(u32, quarter_rtts, 5);
213 		hctx->ccid3hctx_last_win_count	&= 0xF;		/* mod 16 */
214 
215 		ccid3_pr_debug("now at %#X\n", hctx->ccid3hctx_last_win_count);
216 	}
217 }
218 
219 static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
220 {
221 	struct sock *sk = (struct sock *)data;
222 	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
223 	struct timeval now;
224 	unsigned long t_nfb = USEC_PER_SEC / 5;
225 
226 	bh_lock_sock(sk);
227 	if (sock_owned_by_user(sk)) {
228 		/* Try again later. */
229 		/* XXX: set some sensible MIB */
230 		goto restart_timer;
231 	}
232 
233 	ccid3_pr_debug("%s(%p, state=%s) - entry \n", dccp_role(sk), sk,
234 		       ccid3_tx_state_name(hctx->ccid3hctx_state));
235 
236 	hctx->ccid3hctx_idle = 1;
237 
238 	switch (hctx->ccid3hctx_state) {
239 	case TFRC_SSTATE_NO_FBACK:
240 		/* RFC 3448, 4.4: Halve send rate directly */
241 		hctx->ccid3hctx_x = max(hctx->ccid3hctx_x / 2,
242 					(((__u64)hctx->ccid3hctx_s) << 6) /
243 								    TFRC_T_MBI);
244 
245 		ccid3_pr_debug("%s(%p, state=%s), updated tx rate to %u "
246 			       "bytes/s\n", dccp_role(sk), sk,
247 			       ccid3_tx_state_name(hctx->ccid3hctx_state),
248 			       (unsigned)(hctx->ccid3hctx_x >> 6));
249 		/* The value of R is still undefined and so we can not recompute
250 		 * the timout value. Keep initial value as per [RFC 4342, 5]. */
251 		t_nfb = TFRC_INITIAL_TIMEOUT;
252 		ccid3_update_send_interval(hctx);
253 		break;
254 	case TFRC_SSTATE_FBACK:
255 		/*
256 		 *  Modify the cached value of X_recv [RFC 3448, 4.4]
257 		 *
258 		 *  If (p == 0 || X_calc > 2 * X_recv)
259 		 *    X_recv = max(X_recv / 2, s / (2 * t_mbi));
260 		 *  Else
261 		 *    X_recv = X_calc / 4;
262 		 *
263 		 *  Note that X_recv is scaled by 2^6 while X_calc is not
264 		 */
265 		BUG_ON(hctx->ccid3hctx_p && !hctx->ccid3hctx_x_calc);
266 
267 		if (hctx->ccid3hctx_p == 0 ||
268 		    (hctx->ccid3hctx_x_calc > (hctx->ccid3hctx_x_recv >> 5))) {
269 
270 			hctx->ccid3hctx_x_recv =
271 				max(hctx->ccid3hctx_x_recv / 2,
272 				    (((__u64)hctx->ccid3hctx_s) << 6) /
273 							      (2 * TFRC_T_MBI));
274 
275 			if (hctx->ccid3hctx_p == 0)
276 				dccp_timestamp(sk, &now);
277 		} else {
278 			hctx->ccid3hctx_x_recv = hctx->ccid3hctx_x_calc;
279 			hctx->ccid3hctx_x_recv <<= 4;
280 		}
281 		/* Now recalculate X [RFC 3448, 4.3, step (4)] */
282 		ccid3_hc_tx_update_x(sk, &now);
283 		/*
284 		 * Schedule no feedback timer to expire in
285 		 * max(t_RTO, 2 * s/X)  =  max(t_RTO, 2 * t_ipi)
286 		 * See comments in packet_recv() regarding the value of t_RTO.
287 		 */
288 		t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
289 		break;
290 	case TFRC_SSTATE_NO_SENT:
291 		DCCP_BUG("%s(%p) - Illegal state NO_SENT", dccp_role(sk), sk);
292 		/* fall through */
293 	case TFRC_SSTATE_TERM:
294 		goto out;
295 	}
296 
297 restart_timer:
298 	sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
299 			   jiffies + usecs_to_jiffies(t_nfb));
300 out:
301 	bh_unlock_sock(sk);
302 	sock_put(sk);
303 }
304 
305 /*
306  * returns
307  *   > 0: delay (in msecs) that should pass before actually sending
308  *   = 0: can send immediately
309  *   < 0: error condition; do not send packet
310  */
311 static int ccid3_hc_tx_send_packet(struct sock *sk, struct sk_buff *skb)
312 {
313 	struct dccp_sock *dp = dccp_sk(sk);
314 	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
315 	struct timeval now;
316 	suseconds_t delay;
317 
318 	BUG_ON(hctx == NULL);
319 
320 	/*
321 	 * This function is called only for Data and DataAck packets. Sending
322 	 * zero-sized Data(Ack)s is theoretically possible, but for congestion
323 	 * control this case is pathological - ignore it.
324 	 */
325 	if (unlikely(skb->len == 0))
326 		return -EBADMSG;
327 
328 	dccp_timestamp(sk, &now);
329 
330 	switch (hctx->ccid3hctx_state) {
331 	case TFRC_SSTATE_NO_SENT:
332 		sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
333 			       (jiffies +
334 				usecs_to_jiffies(TFRC_INITIAL_TIMEOUT)));
335 		hctx->ccid3hctx_last_win_count	 = 0;
336 		hctx->ccid3hctx_t_last_win_count = now;
337 
338 		/* Set t_0 for initial packet */
339 		hctx->ccid3hctx_t_nom = now;
340 
341 		hctx->ccid3hctx_s = skb->len;
342 
343 		/*
344 		 * Use initial RTT sample when available: recommended by erratum
345 		 * to RFC 4342. This implements the initialisation procedure of
346 		 * draft rfc3448bis, section 4.2. Remember, X is scaled by 2^6.
347 		 */
348 		if (dp->dccps_syn_rtt) {
349 			ccid3_pr_debug("SYN RTT = %uus\n", dp->dccps_syn_rtt);
350 			hctx->ccid3hctx_rtt  = dp->dccps_syn_rtt;
351 			hctx->ccid3hctx_x    = rfc3390_initial_rate(sk);
352 			hctx->ccid3hctx_t_ld = now;
353 		} else {
354 			/* Sender does not have RTT sample: X = MSS/second */
355 			hctx->ccid3hctx_x = dp->dccps_mss_cache;
356 			hctx->ccid3hctx_x <<= 6;
357 		}
358 		ccid3_update_send_interval(hctx);
359 
360 		ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
361 		break;
362 	case TFRC_SSTATE_NO_FBACK:
363 	case TFRC_SSTATE_FBACK:
364 		delay = timeval_delta(&hctx->ccid3hctx_t_nom, &now);
365 		ccid3_pr_debug("delay=%ld\n", (long)delay);
366 		/*
367 		 *	Scheduling of packet transmissions [RFC 3448, 4.6]
368 		 *
369 		 * if (t_now > t_nom - delta)
370 		 *       // send the packet now
371 		 * else
372 		 *       // send the packet in (t_nom - t_now) milliseconds.
373 		 */
374 		if (delay - (suseconds_t)hctx->ccid3hctx_delta >= 0)
375 			return delay / 1000L;
376 
377 		ccid3_hc_tx_update_win_count(hctx, &now);
378 		break;
379 	case TFRC_SSTATE_TERM:
380 		DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
381 		return -EINVAL;
382 	}
383 
384 	/* prepare to send now (add options etc.) */
385 	dp->dccps_hc_tx_insert_options = 1;
386 	DCCP_SKB_CB(skb)->dccpd_ccval = hctx->ccid3hctx_last_win_count;
387 	hctx->ccid3hctx_idle = 0;
388 
389 	/* set the nominal send time for the next following packet */
390 	timeval_add_usecs(&hctx->ccid3hctx_t_nom, hctx->ccid3hctx_t_ipi);
391 
392 	return 0;
393 }
394 
395 static void ccid3_hc_tx_packet_sent(struct sock *sk, int more,
396 				    unsigned int len)
397 {
398 	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
399 	struct timeval now;
400 	struct dccp_tx_hist_entry *packet;
401 
402 	BUG_ON(hctx == NULL);
403 
404 	ccid3_hc_tx_update_s(hctx, len);
405 
406 	packet = dccp_tx_hist_entry_new(ccid3_tx_hist, GFP_ATOMIC);
407 	if (unlikely(packet == NULL)) {
408 		DCCP_CRIT("packet history - out of memory!");
409 		return;
410 	}
411 	dccp_tx_hist_add_entry(&hctx->ccid3hctx_hist, packet);
412 
413 	dccp_timestamp(sk, &now);
414 	packet->dccphtx_tstamp = now;
415 	packet->dccphtx_seqno  = dccp_sk(sk)->dccps_gss;
416 	packet->dccphtx_rtt    = hctx->ccid3hctx_rtt;
417 	packet->dccphtx_sent   = 1;
418 }
419 
420 static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
421 {
422 	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
423 	struct ccid3_options_received *opt_recv;
424 	struct dccp_tx_hist_entry *packet;
425 	struct timeval now;
426 	unsigned long t_nfb;
427 	u32 pinv, r_sample;
428 
429 	BUG_ON(hctx == NULL);
430 
431 	/* we are only interested in ACKs */
432 	if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
433 	      DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
434 		return;
435 
436 	opt_recv = &hctx->ccid3hctx_options_received;
437 
438 	switch (hctx->ccid3hctx_state) {
439 	case TFRC_SSTATE_NO_FBACK:
440 	case TFRC_SSTATE_FBACK:
441 		/* get packet from history to look up t_recvdata */
442 		packet = dccp_tx_hist_find_entry(&hctx->ccid3hctx_hist,
443 					      DCCP_SKB_CB(skb)->dccpd_ack_seq);
444 		if (unlikely(packet == NULL)) {
445 			DCCP_WARN("%s(%p), seqno %llu(%s) doesn't exist "
446 				  "in history!\n",  dccp_role(sk), sk,
447 			    (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
448 				dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type));
449 			return;
450 		}
451 
452 		/* Update receive rate in units of 64 * bytes/second */
453 		hctx->ccid3hctx_x_recv = opt_recv->ccid3or_receive_rate;
454 		hctx->ccid3hctx_x_recv <<= 6;
455 
456 		/* Update loss event rate */
457 		pinv = opt_recv->ccid3or_loss_event_rate;
458 		if (pinv == ~0U || pinv == 0)	       /* see RFC 4342, 8.5   */
459 			hctx->ccid3hctx_p = 0;
460 		else				       /* can not exceed 100% */
461 			hctx->ccid3hctx_p = 1000000 / pinv;
462 
463 		dccp_timestamp(sk, &now);
464 
465 		/*
466 		 * Calculate new round trip sample as per [RFC 3448, 4.3] by
467 		 *	R_sample  =  (now - t_recvdata) - t_elapsed
468 		 */
469 		r_sample = dccp_sample_rtt(sk, &now, &packet->dccphtx_tstamp);
470 
471 		/*
472 		 * Update RTT estimate by
473 		 * If (No feedback recv)
474 		 *    R = R_sample;
475 		 * Else
476 		 *    R = q * R + (1 - q) * R_sample;
477 		 *
478 		 * q is a constant, RFC 3448 recomments 0.9
479 		 */
480 		if (hctx->ccid3hctx_state == TFRC_SSTATE_NO_FBACK) {
481 			/*
482 			 * Larger Initial Windows [RFC 4342, sec. 5]
483 			 */
484 			hctx->ccid3hctx_rtt  = r_sample;
485 			hctx->ccid3hctx_x    = rfc3390_initial_rate(sk);
486 			hctx->ccid3hctx_t_ld = now;
487 
488 			ccid3_update_send_interval(hctx);
489 
490 			ccid3_pr_debug("%s(%p), s=%u, MSS=%u, "
491 				       "R_sample=%uus, X=%u\n", dccp_role(sk),
492 				       sk, hctx->ccid3hctx_s,
493 				       dccp_sk(sk)->dccps_mss_cache, r_sample,
494 				       (unsigned)(hctx->ccid3hctx_x >> 6));
495 
496 			ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
497 		} else {
498 			hctx->ccid3hctx_rtt = (9 * hctx->ccid3hctx_rtt +
499 						   r_sample) / 10;
500 
501 			/* Update sending rate (step 4 of [RFC 3448, 4.3]) */
502 			if (hctx->ccid3hctx_p > 0)
503 				hctx->ccid3hctx_x_calc =
504 					tfrc_calc_x(hctx->ccid3hctx_s,
505 						    hctx->ccid3hctx_rtt,
506 						    hctx->ccid3hctx_p);
507 			ccid3_hc_tx_update_x(sk, &now);
508 
509 			ccid3_pr_debug("%s(%p), RTT=%uus (sample=%uus), s=%u, "
510 				       "p=%u, X_calc=%u, X_recv=%u, X=%u\n",
511 				       dccp_role(sk),
512 				       sk, hctx->ccid3hctx_rtt, r_sample,
513 				       hctx->ccid3hctx_s, hctx->ccid3hctx_p,
514 				       hctx->ccid3hctx_x_calc,
515 				       (unsigned)(hctx->ccid3hctx_x_recv >> 6),
516 				       (unsigned)(hctx->ccid3hctx_x >> 6));
517 		}
518 
519 		/* unschedule no feedback timer */
520 		sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
521 
522 		/* remove all packets older than the one acked from history */
523 		dccp_tx_hist_purge_older(ccid3_tx_hist,
524 					 &hctx->ccid3hctx_hist, packet);
525 		/*
526 		 * As we have calculated new ipi, delta, t_nom it is possible
527 		 * that we now can send a packet, so wake up dccp_wait_for_ccid
528 		 */
529 		sk->sk_write_space(sk);
530 
531 		/*
532 		 * Update timeout interval for the nofeedback timer.
533 		 * We use a configuration option to increase the lower bound.
534 		 * This can help avoid triggering the nofeedback timer too
535 		 * often ('spinning') on LANs with small RTTs.
536 		 */
537 		hctx->ccid3hctx_t_rto = max_t(u32, 4 * hctx->ccid3hctx_rtt,
538 						   CONFIG_IP_DCCP_CCID3_RTO *
539 						   (USEC_PER_SEC/1000));
540 		/*
541 		 * Schedule no feedback timer to expire in
542 		 * max(t_RTO, 2 * s/X)  =  max(t_RTO, 2 * t_ipi)
543 		 */
544 		t_nfb = max(hctx->ccid3hctx_t_rto, 2 * hctx->ccid3hctx_t_ipi);
545 
546 		ccid3_pr_debug("%s(%p), Scheduled no feedback timer to "
547 			       "expire in %lu jiffies (%luus)\n",
548 			       dccp_role(sk),
549 			       sk, usecs_to_jiffies(t_nfb), t_nfb);
550 
551 		sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
552 				   jiffies + usecs_to_jiffies(t_nfb));
553 
554 		/* set idle flag */
555 		hctx->ccid3hctx_idle = 1;
556 		break;
557 	case TFRC_SSTATE_NO_SENT:	/* fall through */
558 	case TFRC_SSTATE_TERM:		/* ignore feedback when closing */
559 		break;
560 	}
561 }
562 
563 static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
564 				     unsigned char len, u16 idx,
565 				     unsigned char *value)
566 {
567 	int rc = 0;
568 	const struct dccp_sock *dp = dccp_sk(sk);
569 	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
570 	struct ccid3_options_received *opt_recv;
571 
572 	BUG_ON(hctx == NULL);
573 
574 	opt_recv = &hctx->ccid3hctx_options_received;
575 
576 	if (opt_recv->ccid3or_seqno != dp->dccps_gsr) {
577 		opt_recv->ccid3or_seqno		     = dp->dccps_gsr;
578 		opt_recv->ccid3or_loss_event_rate    = ~0;
579 		opt_recv->ccid3or_loss_intervals_idx = 0;
580 		opt_recv->ccid3or_loss_intervals_len = 0;
581 		opt_recv->ccid3or_receive_rate	     = 0;
582 	}
583 
584 	switch (option) {
585 	case TFRC_OPT_LOSS_EVENT_RATE:
586 		if (unlikely(len != 4)) {
587 			DCCP_WARN("%s(%p), invalid len %d "
588 				  "for TFRC_OPT_LOSS_EVENT_RATE\n",
589 				  dccp_role(sk), sk, len);
590 			rc = -EINVAL;
591 		} else {
592 			opt_recv->ccid3or_loss_event_rate =
593 						ntohl(*(__be32 *)value);
594 			ccid3_pr_debug("%s(%p), LOSS_EVENT_RATE=%u\n",
595 				       dccp_role(sk), sk,
596 				       opt_recv->ccid3or_loss_event_rate);
597 		}
598 		break;
599 	case TFRC_OPT_LOSS_INTERVALS:
600 		opt_recv->ccid3or_loss_intervals_idx = idx;
601 		opt_recv->ccid3or_loss_intervals_len = len;
602 		ccid3_pr_debug("%s(%p), LOSS_INTERVALS=(%u, %u)\n",
603 			       dccp_role(sk), sk,
604 			       opt_recv->ccid3or_loss_intervals_idx,
605 			       opt_recv->ccid3or_loss_intervals_len);
606 		break;
607 	case TFRC_OPT_RECEIVE_RATE:
608 		if (unlikely(len != 4)) {
609 			DCCP_WARN("%s(%p), invalid len %d "
610 				  "for TFRC_OPT_RECEIVE_RATE\n",
611 				  dccp_role(sk), sk, len);
612 			rc = -EINVAL;
613 		} else {
614 			opt_recv->ccid3or_receive_rate =
615 						ntohl(*(__be32 *)value);
616 			ccid3_pr_debug("%s(%p), RECEIVE_RATE=%u\n",
617 				       dccp_role(sk), sk,
618 				       opt_recv->ccid3or_receive_rate);
619 		}
620 		break;
621 	}
622 
623 	return rc;
624 }
625 
626 static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
627 {
628 	struct ccid3_hc_tx_sock *hctx = ccid_priv(ccid);
629 
630 	hctx->ccid3hctx_s     = 0;
631 	hctx->ccid3hctx_rtt   = 0;
632 	hctx->ccid3hctx_state = TFRC_SSTATE_NO_SENT;
633 	INIT_LIST_HEAD(&hctx->ccid3hctx_hist);
634 
635 	hctx->ccid3hctx_no_feedback_timer.function =
636 				ccid3_hc_tx_no_feedback_timer;
637 	hctx->ccid3hctx_no_feedback_timer.data     = (unsigned long)sk;
638 	init_timer(&hctx->ccid3hctx_no_feedback_timer);
639 
640 	return 0;
641 }
642 
643 static void ccid3_hc_tx_exit(struct sock *sk)
644 {
645 	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
646 
647 	BUG_ON(hctx == NULL);
648 
649 	ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM);
650 	sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
651 
652 	/* Empty packet history */
653 	dccp_tx_hist_purge(ccid3_tx_hist, &hctx->ccid3hctx_hist);
654 }
655 
656 static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info)
657 {
658 	const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
659 
660 	/* Listen socks doesn't have a private CCID block */
661 	if (sk->sk_state == DCCP_LISTEN)
662 		return;
663 
664 	BUG_ON(hctx == NULL);
665 
666 	info->tcpi_rto = hctx->ccid3hctx_t_rto;
667 	info->tcpi_rtt = hctx->ccid3hctx_rtt;
668 }
669 
670 static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
671 				  u32 __user *optval, int __user *optlen)
672 {
673 	const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
674 	const void *val;
675 
676 	/* Listen socks doesn't have a private CCID block */
677 	if (sk->sk_state == DCCP_LISTEN)
678 		return -EINVAL;
679 
680 	switch (optname) {
681 	case DCCP_SOCKOPT_CCID_TX_INFO:
682 		if (len < sizeof(hctx->ccid3hctx_tfrc))
683 			return -EINVAL;
684 		len = sizeof(hctx->ccid3hctx_tfrc);
685 		val = &hctx->ccid3hctx_tfrc;
686 		break;
687 	default:
688 		return -ENOPROTOOPT;
689 	}
690 
691 	if (put_user(len, optlen) || copy_to_user(optval, val, len))
692 		return -EFAULT;
693 
694 	return 0;
695 }
696 
697 /*
698  *	Receiver Half-Connection Routines
699  */
700 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
701 static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
702 {
703 	static char *ccid3_rx_state_names[] = {
704 	[TFRC_RSTATE_NO_DATA] = "NO_DATA",
705 	[TFRC_RSTATE_DATA]    = "DATA",
706 	[TFRC_RSTATE_TERM]    = "TERM",
707 	};
708 
709 	return ccid3_rx_state_names[state];
710 }
711 #endif
712 
713 static void ccid3_hc_rx_set_state(struct sock *sk,
714 				  enum ccid3_hc_rx_states state)
715 {
716 	struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
717 	enum ccid3_hc_rx_states oldstate = hcrx->ccid3hcrx_state;
718 
719 	ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
720 		       dccp_role(sk), sk, ccid3_rx_state_name(oldstate),
721 		       ccid3_rx_state_name(state));
722 	WARN_ON(state == oldstate);
723 	hcrx->ccid3hcrx_state = state;
724 }
725 
726 static inline void ccid3_hc_rx_update_s(struct ccid3_hc_rx_sock *hcrx, int len)
727 {
728 	if (unlikely(len == 0))	/* don't update on empty packets (e.g. ACKs) */
729 		ccid3_pr_debug("Packet payload length is 0 - not updating\n");
730 	else
731 		hcrx->ccid3hcrx_s = hcrx->ccid3hcrx_s == 0 ? len :
732 				    (9 * hcrx->ccid3hcrx_s + len) / 10;
733 }
734 
735 static void ccid3_hc_rx_send_feedback(struct sock *sk)
736 {
737 	struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
738 	struct dccp_sock *dp = dccp_sk(sk);
739 	struct dccp_rx_hist_entry *packet;
740 	struct timeval now;
741 	suseconds_t delta;
742 
743 	ccid3_pr_debug("%s(%p) - entry \n", dccp_role(sk), sk);
744 
745 	dccp_timestamp(sk, &now);
746 
747 	switch (hcrx->ccid3hcrx_state) {
748 	case TFRC_RSTATE_NO_DATA:
749 		hcrx->ccid3hcrx_x_recv = 0;
750 		break;
751 	case TFRC_RSTATE_DATA:
752 		delta = timeval_delta(&now,
753 				      &hcrx->ccid3hcrx_tstamp_last_feedback);
754 		DCCP_BUG_ON(delta < 0);
755 		hcrx->ccid3hcrx_x_recv =
756 			scaled_div32(hcrx->ccid3hcrx_bytes_recv, delta);
757 		break;
758 	case TFRC_RSTATE_TERM:
759 		DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
760 		return;
761 	}
762 
763 	packet = dccp_rx_hist_find_data_packet(&hcrx->ccid3hcrx_hist);
764 	if (unlikely(packet == NULL)) {
765 		DCCP_WARN("%s(%p), no data packet in history!\n",
766 			  dccp_role(sk), sk);
767 		return;
768 	}
769 
770 	hcrx->ccid3hcrx_tstamp_last_feedback = now;
771 	hcrx->ccid3hcrx_ccval_last_counter   = packet->dccphrx_ccval;
772 	hcrx->ccid3hcrx_bytes_recv	     = 0;
773 
774 	/* Elapsed time information [RFC 4340, 13.2] in units of 10 * usecs */
775 	delta = timeval_delta(&now, &packet->dccphrx_tstamp);
776 	DCCP_BUG_ON(delta < 0);
777 	hcrx->ccid3hcrx_elapsed_time = delta / 10;
778 
779 	if (hcrx->ccid3hcrx_p == 0)
780 		hcrx->ccid3hcrx_pinv = ~0U;	/* see RFC 4342, 8.5 */
781 	else if (hcrx->ccid3hcrx_p > 1000000) {
782 		DCCP_WARN("p (%u) > 100%%\n", hcrx->ccid3hcrx_p);
783 		hcrx->ccid3hcrx_pinv = 1;	/* use 100% in this case */
784 	} else
785 		hcrx->ccid3hcrx_pinv = 1000000 / hcrx->ccid3hcrx_p;
786 
787 	dp->dccps_hc_rx_insert_options = 1;
788 	dccp_send_ack(sk);
789 }
790 
791 static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
792 {
793 	const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
794 	__be32 x_recv, pinv;
795 
796 	BUG_ON(hcrx == NULL);
797 
798 	if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
799 		return 0;
800 
801 	DCCP_SKB_CB(skb)->dccpd_ccval = hcrx->ccid3hcrx_ccval_last_counter;
802 
803 	if (dccp_packet_without_ack(skb))
804 		return 0;
805 
806 	x_recv = htonl(hcrx->ccid3hcrx_x_recv);
807 	pinv   = htonl(hcrx->ccid3hcrx_pinv);
808 
809 	if ((hcrx->ccid3hcrx_elapsed_time != 0 &&
810 	     dccp_insert_option_elapsed_time(sk, skb,
811 					     hcrx->ccid3hcrx_elapsed_time)) ||
812 	    dccp_insert_option_timestamp(sk, skb) ||
813 	    dccp_insert_option(sk, skb, TFRC_OPT_LOSS_EVENT_RATE,
814 			       &pinv, sizeof(pinv)) ||
815 	    dccp_insert_option(sk, skb, TFRC_OPT_RECEIVE_RATE,
816 			       &x_recv, sizeof(x_recv)))
817 		return -1;
818 
819 	return 0;
820 }
821 
822 static int ccid3_hc_rx_detect_loss(struct sock *sk,
823 				    struct dccp_rx_hist_entry *packet)
824 {
825 	struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
826 	struct dccp_rx_hist_entry *rx_hist =
827 				dccp_rx_hist_head(&hcrx->ccid3hcrx_hist);
828 	u64 seqno = packet->dccphrx_seqno;
829 	u64 tmp_seqno;
830 	int loss = 0;
831 	u8 ccval;
832 
833 
834 	tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
835 
836 	if (!rx_hist ||
837 	   follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
838 		hcrx->ccid3hcrx_seqno_nonloss = seqno;
839 		hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
840 		goto detect_out;
841 	}
842 
843 
844 	while (dccp_delta_seqno(hcrx->ccid3hcrx_seqno_nonloss, seqno)
845 	   > TFRC_RECV_NUM_LATE_LOSS) {
846 		loss = 1;
847 		dccp_li_update_li(sk, ccid3_li_hist,
848 				  &hcrx->ccid3hcrx_li_hist,
849 				  &hcrx->ccid3hcrx_hist,
850 				  &hcrx->ccid3hcrx_tstamp_last_feedback,
851 				  hcrx->ccid3hcrx_s,
852 				  hcrx->ccid3hcrx_bytes_recv,
853 				  hcrx->ccid3hcrx_x_recv,
854 				  hcrx->ccid3hcrx_seqno_nonloss,
855 				  hcrx->ccid3hcrx_ccval_nonloss);
856 		tmp_seqno = hcrx->ccid3hcrx_seqno_nonloss;
857 		dccp_inc_seqno(&tmp_seqno);
858 		hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
859 		dccp_inc_seqno(&tmp_seqno);
860 		while (dccp_rx_hist_find_entry(&hcrx->ccid3hcrx_hist,
861 		   tmp_seqno, &ccval)) {
862 			hcrx->ccid3hcrx_seqno_nonloss = tmp_seqno;
863 			hcrx->ccid3hcrx_ccval_nonloss = ccval;
864 			dccp_inc_seqno(&tmp_seqno);
865 		}
866 	}
867 
868 	/* FIXME - this code could be simplified with above while */
869 	/* but works at moment */
870 	if (follows48(packet->dccphrx_seqno, hcrx->ccid3hcrx_seqno_nonloss)) {
871 		hcrx->ccid3hcrx_seqno_nonloss = seqno;
872 		hcrx->ccid3hcrx_ccval_nonloss = packet->dccphrx_ccval;
873 	}
874 
875 detect_out:
876 	dccp_rx_hist_add_packet(ccid3_rx_hist, &hcrx->ccid3hcrx_hist,
877 		   &hcrx->ccid3hcrx_li_hist, packet,
878 		   hcrx->ccid3hcrx_seqno_nonloss);
879 	return loss;
880 }
881 
882 static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
883 {
884 	struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
885 	const struct dccp_options_received *opt_recv;
886 	struct dccp_rx_hist_entry *packet;
887 	struct timeval now;
888 	u32 p_prev, r_sample, rtt_prev;
889 	int loss, payload_size;
890 
891 	BUG_ON(hcrx == NULL);
892 
893 	opt_recv = &dccp_sk(sk)->dccps_options_received;
894 
895 	switch (DCCP_SKB_CB(skb)->dccpd_type) {
896 	case DCCP_PKT_ACK:
897 		if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
898 			return;
899 	case DCCP_PKT_DATAACK:
900 		if (opt_recv->dccpor_timestamp_echo == 0)
901 			break;
902 		rtt_prev = hcrx->ccid3hcrx_rtt;
903 		dccp_timestamp(sk, &now);
904 		r_sample = dccp_sample_rtt(sk, &now, NULL);
905 
906 		if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
907 			hcrx->ccid3hcrx_rtt = r_sample;
908 		else
909 			hcrx->ccid3hcrx_rtt = (hcrx->ccid3hcrx_rtt * 9) / 10 +
910 					      r_sample / 10;
911 
912 		if (rtt_prev != hcrx->ccid3hcrx_rtt)
913 			ccid3_pr_debug("%s(%p), New RTT=%uus, elapsed time=%u\n",
914 				       dccp_role(sk), sk, hcrx->ccid3hcrx_rtt,
915 				       opt_recv->dccpor_elapsed_time);
916 		break;
917 	case DCCP_PKT_DATA:
918 		break;
919 	default: /* We're not interested in other packet types, move along */
920 		return;
921 	}
922 
923 	packet = dccp_rx_hist_entry_new(ccid3_rx_hist, sk, opt_recv->dccpor_ndp,
924 					skb, GFP_ATOMIC);
925 	if (unlikely(packet == NULL)) {
926 		DCCP_WARN("%s(%p), Not enough mem to add rx packet "
927 			  "to history, consider it lost!\n", dccp_role(sk), sk);
928 		return;
929 	}
930 
931 	loss = ccid3_hc_rx_detect_loss(sk, packet);
932 
933 	if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK)
934 		return;
935 
936 	payload_size = skb->len - dccp_hdr(skb)->dccph_doff * 4;
937 	ccid3_hc_rx_update_s(hcrx, payload_size);
938 
939 	switch (hcrx->ccid3hcrx_state) {
940 	case TFRC_RSTATE_NO_DATA:
941 		ccid3_pr_debug("%s(%p, state=%s), skb=%p, sending initial "
942 			       "feedback\n", dccp_role(sk), sk,
943 			       dccp_state_name(sk->sk_state), skb);
944 		ccid3_hc_rx_send_feedback(sk);
945 		ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA);
946 		return;
947 	case TFRC_RSTATE_DATA:
948 		hcrx->ccid3hcrx_bytes_recv += payload_size;
949 		if (loss)
950 			break;
951 
952 		dccp_timestamp(sk, &now);
953 		if ((timeval_delta(&now, &hcrx->ccid3hcrx_tstamp_last_ack) -
954 		     (suseconds_t)hcrx->ccid3hcrx_rtt) >= 0) {
955 			hcrx->ccid3hcrx_tstamp_last_ack = now;
956 			ccid3_hc_rx_send_feedback(sk);
957 		}
958 		return;
959 	case TFRC_RSTATE_TERM:
960 		DCCP_BUG("%s(%p) - Illegal state TERM", dccp_role(sk), sk);
961 		return;
962 	}
963 
964 	/* Dealing with packet loss */
965 	ccid3_pr_debug("%s(%p, state=%s), data loss! Reacting...\n",
966 		       dccp_role(sk), sk, dccp_state_name(sk->sk_state));
967 
968 	p_prev = hcrx->ccid3hcrx_p;
969 
970 	/* Calculate loss event rate */
971 	if (!list_empty(&hcrx->ccid3hcrx_li_hist)) {
972 		u32 i_mean = dccp_li_hist_calc_i_mean(&hcrx->ccid3hcrx_li_hist);
973 
974 		/* Scaling up by 1000000 as fixed decimal */
975 		if (i_mean != 0)
976 			hcrx->ccid3hcrx_p = 1000000 / i_mean;
977 	} else
978 		DCCP_BUG("empty loss history");
979 
980 	if (hcrx->ccid3hcrx_p > p_prev) {
981 		ccid3_hc_rx_send_feedback(sk);
982 		return;
983 	}
984 }
985 
986 static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
987 {
988 	struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid);
989 
990 	ccid3_pr_debug("entry\n");
991 
992 	hcrx->ccid3hcrx_state = TFRC_RSTATE_NO_DATA;
993 	INIT_LIST_HEAD(&hcrx->ccid3hcrx_hist);
994 	INIT_LIST_HEAD(&hcrx->ccid3hcrx_li_hist);
995 	dccp_timestamp(sk, &hcrx->ccid3hcrx_tstamp_last_ack);
996 	hcrx->ccid3hcrx_tstamp_last_feedback = hcrx->ccid3hcrx_tstamp_last_ack;
997 	hcrx->ccid3hcrx_s   = 0;
998 	hcrx->ccid3hcrx_rtt = 0;
999 	return 0;
1000 }
1001 
1002 static void ccid3_hc_rx_exit(struct sock *sk)
1003 {
1004 	struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1005 
1006 	BUG_ON(hcrx == NULL);
1007 
1008 	ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM);
1009 
1010 	/* Empty packet history */
1011 	dccp_rx_hist_purge(ccid3_rx_hist, &hcrx->ccid3hcrx_hist);
1012 
1013 	/* Empty loss interval history */
1014 	dccp_li_hist_purge(ccid3_li_hist, &hcrx->ccid3hcrx_li_hist);
1015 }
1016 
1017 static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
1018 {
1019 	const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1020 
1021 	/* Listen socks doesn't have a private CCID block */
1022 	if (sk->sk_state == DCCP_LISTEN)
1023 		return;
1024 
1025 	BUG_ON(hcrx == NULL);
1026 
1027 	info->tcpi_ca_state = hcrx->ccid3hcrx_state;
1028 	info->tcpi_options  |= TCPI_OPT_TIMESTAMPS;
1029 	info->tcpi_rcv_rtt  = hcrx->ccid3hcrx_rtt;
1030 }
1031 
1032 static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len,
1033 				  u32 __user *optval, int __user *optlen)
1034 {
1035 	const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1036 	const void *val;
1037 
1038 	/* Listen socks doesn't have a private CCID block */
1039 	if (sk->sk_state == DCCP_LISTEN)
1040 		return -EINVAL;
1041 
1042 	switch (optname) {
1043 	case DCCP_SOCKOPT_CCID_RX_INFO:
1044 		if (len < sizeof(hcrx->ccid3hcrx_tfrc))
1045 			return -EINVAL;
1046 		len = sizeof(hcrx->ccid3hcrx_tfrc);
1047 		val = &hcrx->ccid3hcrx_tfrc;
1048 		break;
1049 	default:
1050 		return -ENOPROTOOPT;
1051 	}
1052 
1053 	if (put_user(len, optlen) || copy_to_user(optval, val, len))
1054 		return -EFAULT;
1055 
1056 	return 0;
1057 }
1058 
1059 static struct ccid_operations ccid3 = {
1060 	.ccid_id		   = DCCPC_CCID3,
1061 	.ccid_name		   = "ccid3",
1062 	.ccid_owner		   = THIS_MODULE,
1063 	.ccid_hc_tx_obj_size	   = sizeof(struct ccid3_hc_tx_sock),
1064 	.ccid_hc_tx_init	   = ccid3_hc_tx_init,
1065 	.ccid_hc_tx_exit	   = ccid3_hc_tx_exit,
1066 	.ccid_hc_tx_send_packet	   = ccid3_hc_tx_send_packet,
1067 	.ccid_hc_tx_packet_sent	   = ccid3_hc_tx_packet_sent,
1068 	.ccid_hc_tx_packet_recv	   = ccid3_hc_tx_packet_recv,
1069 	.ccid_hc_tx_parse_options  = ccid3_hc_tx_parse_options,
1070 	.ccid_hc_rx_obj_size	   = sizeof(struct ccid3_hc_rx_sock),
1071 	.ccid_hc_rx_init	   = ccid3_hc_rx_init,
1072 	.ccid_hc_rx_exit	   = ccid3_hc_rx_exit,
1073 	.ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options,
1074 	.ccid_hc_rx_packet_recv	   = ccid3_hc_rx_packet_recv,
1075 	.ccid_hc_rx_get_info	   = ccid3_hc_rx_get_info,
1076 	.ccid_hc_tx_get_info	   = ccid3_hc_tx_get_info,
1077 	.ccid_hc_rx_getsockopt	   = ccid3_hc_rx_getsockopt,
1078 	.ccid_hc_tx_getsockopt	   = ccid3_hc_tx_getsockopt,
1079 };
1080 
1081 #ifdef CONFIG_IP_DCCP_CCID3_DEBUG
1082 module_param(ccid3_debug, int, 0444);
1083 MODULE_PARM_DESC(ccid3_debug, "Enable debug messages");
1084 #endif
1085 
1086 static __init int ccid3_module_init(void)
1087 {
1088 	int rc = -ENOBUFS;
1089 
1090 	ccid3_rx_hist = dccp_rx_hist_new("ccid3");
1091 	if (ccid3_rx_hist == NULL)
1092 		goto out;
1093 
1094 	ccid3_tx_hist = dccp_tx_hist_new("ccid3");
1095 	if (ccid3_tx_hist == NULL)
1096 		goto out_free_rx;
1097 
1098 	ccid3_li_hist = dccp_li_hist_new("ccid3");
1099 	if (ccid3_li_hist == NULL)
1100 		goto out_free_tx;
1101 
1102 	rc = ccid_register(&ccid3);
1103 	if (rc != 0)
1104 		goto out_free_loss_interval_history;
1105 out:
1106 	return rc;
1107 
1108 out_free_loss_interval_history:
1109 	dccp_li_hist_delete(ccid3_li_hist);
1110 	ccid3_li_hist = NULL;
1111 out_free_tx:
1112 	dccp_tx_hist_delete(ccid3_tx_hist);
1113 	ccid3_tx_hist = NULL;
1114 out_free_rx:
1115 	dccp_rx_hist_delete(ccid3_rx_hist);
1116 	ccid3_rx_hist = NULL;
1117 	goto out;
1118 }
1119 module_init(ccid3_module_init);
1120 
1121 static __exit void ccid3_module_exit(void)
1122 {
1123 	ccid_unregister(&ccid3);
1124 
1125 	if (ccid3_tx_hist != NULL) {
1126 		dccp_tx_hist_delete(ccid3_tx_hist);
1127 		ccid3_tx_hist = NULL;
1128 	}
1129 	if (ccid3_rx_hist != NULL) {
1130 		dccp_rx_hist_delete(ccid3_rx_hist);
1131 		ccid3_rx_hist = NULL;
1132 	}
1133 	if (ccid3_li_hist != NULL) {
1134 		dccp_li_hist_delete(ccid3_li_hist);
1135 		ccid3_li_hist = NULL;
1136 	}
1137 }
1138 module_exit(ccid3_module_exit);
1139 
1140 MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>, "
1141 	      "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
1142 MODULE_DESCRIPTION("DCCP TFRC CCID3 CCID");
1143 MODULE_LICENSE("GPL");
1144 MODULE_ALIAS("net-dccp-ccid-3");
1145