xref: /linux/net/dccp/ccids/ccid3.c (revision 14b42963f64b98ab61fa9723c03d71aa5ef4f862)
1 /*
2  *  net/dccp/ccids/ccid3.c
3  *
4  *  Copyright (c) 2005 The University of Waikato, Hamilton, New Zealand.
5  *  Copyright (c) 2005-6 Ian McDonald <imcdnzl@gmail.com>
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 
37 #include "../ccid.h"
38 #include "../dccp.h"
39 #include "lib/packet_history.h"
40 #include "lib/loss_interval.h"
41 #include "lib/tfrc.h"
42 #include "ccid3.h"
43 
44 /*
45  * Reason for maths here is to avoid 32 bit overflow when a is big.
46  * With this we get close to the limit.
47  */
48 static u32 usecs_div(const u32 a, const u32 b)
49 {
50 	const u32 div = a < (UINT_MAX / (USEC_PER_SEC /    10)) ?    10 :
51 			a < (UINT_MAX / (USEC_PER_SEC /    50)) ?    50 :
52 			a < (UINT_MAX / (USEC_PER_SEC /   100)) ?   100 :
53 			a < (UINT_MAX / (USEC_PER_SEC /   500)) ?   500 :
54 			a < (UINT_MAX / (USEC_PER_SEC /  1000)) ?  1000 :
55 			a < (UINT_MAX / (USEC_PER_SEC /  5000)) ?  5000 :
56 			a < (UINT_MAX / (USEC_PER_SEC / 10000)) ? 10000 :
57 			a < (UINT_MAX / (USEC_PER_SEC / 50000)) ? 50000 :
58 								 100000;
59 	const u32 tmp = a * (USEC_PER_SEC / div);
60 	return (b >= 2 * div) ? tmp / (b / div) : tmp;
61 }
62 
63 static int ccid3_debug;
64 
65 #ifdef CCID3_DEBUG
66 #define ccid3_pr_debug(format, a...) \
67 	do { if (ccid3_debug) \
68 		printk(KERN_DEBUG "%s: " format, __FUNCTION__, ##a); \
69 	} while (0)
70 #else
71 #define ccid3_pr_debug(format, a...)
72 #endif
73 
74 static struct dccp_tx_hist *ccid3_tx_hist;
75 static struct dccp_rx_hist *ccid3_rx_hist;
76 static struct dccp_li_hist *ccid3_li_hist;
77 
78 /* TFRC sender states */
79 enum ccid3_hc_tx_states {
80        	TFRC_SSTATE_NO_SENT = 1,
81 	TFRC_SSTATE_NO_FBACK,
82 	TFRC_SSTATE_FBACK,
83 	TFRC_SSTATE_TERM,
84 };
85 
86 #ifdef CCID3_DEBUG
87 static const char *ccid3_tx_state_name(enum ccid3_hc_tx_states state)
88 {
89 	static char *ccid3_state_names[] = {
90 	[TFRC_SSTATE_NO_SENT]  = "NO_SENT",
91 	[TFRC_SSTATE_NO_FBACK] = "NO_FBACK",
92 	[TFRC_SSTATE_FBACK]    = "FBACK",
93 	[TFRC_SSTATE_TERM]     = "TERM",
94 	};
95 
96 	return ccid3_state_names[state];
97 }
98 #endif
99 
100 static void ccid3_hc_tx_set_state(struct sock *sk,
101 				  enum ccid3_hc_tx_states state)
102 {
103 	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
104 	enum ccid3_hc_tx_states oldstate = hctx->ccid3hctx_state;
105 
106 	ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
107 		       dccp_role(sk), sk, ccid3_tx_state_name(oldstate),
108 		       ccid3_tx_state_name(state));
109 	WARN_ON(state == oldstate);
110 	hctx->ccid3hctx_state = state;
111 }
112 
113 /* Calculate new t_ipi (inter packet interval) by t_ipi = s / X_inst */
114 static inline void ccid3_calc_new_t_ipi(struct ccid3_hc_tx_sock *hctx)
115 {
116 	/*
117 	 * If no feedback spec says t_ipi is 1 second (set elsewhere and then
118 	 * doubles after every no feedback timer (separate function)
119 	 */
120 	if (hctx->ccid3hctx_state != TFRC_SSTATE_NO_FBACK)
121 		hctx->ccid3hctx_t_ipi = usecs_div(hctx->ccid3hctx_s,
122 						  hctx->ccid3hctx_x);
123 }
124 
125 /* Calculate new delta by delta = min(t_ipi / 2, t_gran / 2) */
126 static inline void ccid3_calc_new_delta(struct ccid3_hc_tx_sock *hctx)
127 {
128 	hctx->ccid3hctx_delta = min_t(u32, hctx->ccid3hctx_t_ipi / 2,
129 					   TFRC_OPSYS_HALF_TIME_GRAN);
130 }
131 
132 /*
133  * Update X by
134  *    If (p > 0)
135  *       x_calc = calcX(s, R, p);
136  *       X = max(min(X_calc, 2 * X_recv), s / t_mbi);
137  *    Else
138  *       If (now - tld >= R)
139  *          X = max(min(2 * X, 2 * X_recv), s / R);
140  *          tld = now;
141  */
142 static void ccid3_hc_tx_update_x(struct sock *sk)
143 {
144 	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
145 
146 	/* To avoid large error in calcX */
147 	if (hctx->ccid3hctx_p >= TFRC_SMALLEST_P) {
148 		hctx->ccid3hctx_x_calc = tfrc_calc_x(hctx->ccid3hctx_s,
149 						     hctx->ccid3hctx_rtt,
150 						     hctx->ccid3hctx_p);
151 		hctx->ccid3hctx_x = max_t(u32, min_t(u32, hctx->ccid3hctx_x_calc,
152 							  2 * hctx->ccid3hctx_x_recv),
153 					       (hctx->ccid3hctx_s /
154 					        TFRC_MAX_BACK_OFF_TIME));
155 	} else {
156 		struct timeval now;
157 
158 		dccp_timestamp(sk, &now);
159 	       	if (timeval_delta(&now, &hctx->ccid3hctx_t_ld) >=
160 		    hctx->ccid3hctx_rtt) {
161 			hctx->ccid3hctx_x = max_t(u32, min_t(u32, hctx->ccid3hctx_x_recv,
162 								  hctx->ccid3hctx_x) * 2,
163 						       usecs_div(hctx->ccid3hctx_s,
164 							       	 hctx->ccid3hctx_rtt));
165 			hctx->ccid3hctx_t_ld = now;
166 		}
167 	}
168 }
169 
170 static void ccid3_hc_tx_no_feedback_timer(unsigned long data)
171 {
172 	struct sock *sk = (struct sock *)data;
173 	unsigned long next_tmout = 0;
174 	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
175 
176 	bh_lock_sock(sk);
177 	if (sock_owned_by_user(sk)) {
178 		/* Try again later. */
179 		/* XXX: set some sensible MIB */
180 		sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
181 			       jiffies + HZ / 5);
182 		goto out;
183 	}
184 
185 	ccid3_pr_debug("%s, sk=%p, state=%s\n", dccp_role(sk), sk,
186 		       ccid3_tx_state_name(hctx->ccid3hctx_state));
187 
188 	switch (hctx->ccid3hctx_state) {
189 	case TFRC_SSTATE_TERM:
190 		goto out;
191 	case TFRC_SSTATE_NO_FBACK:
192 		/* Halve send rate */
193 		hctx->ccid3hctx_x /= 2;
194 		if (hctx->ccid3hctx_x < (hctx->ccid3hctx_s /
195 					 TFRC_MAX_BACK_OFF_TIME))
196 			hctx->ccid3hctx_x = (hctx->ccid3hctx_s /
197 					     TFRC_MAX_BACK_OFF_TIME);
198 
199 		ccid3_pr_debug("%s, sk=%p, state=%s, updated tx rate to %d "
200 			       "bytes/s\n",
201 			       dccp_role(sk), sk,
202 			       ccid3_tx_state_name(hctx->ccid3hctx_state),
203 			       hctx->ccid3hctx_x);
204 		next_tmout = max_t(u32, 2 * usecs_div(hctx->ccid3hctx_s,
205 						      hctx->ccid3hctx_x),
206 					TFRC_INITIAL_TIMEOUT);
207 		/*
208 		 * FIXME - not sure above calculation is correct. See section
209 		 * 5 of CCID3 11 should adjust tx_t_ipi and double that to
210 		 * achieve it really
211 		 */
212 		break;
213 	case TFRC_SSTATE_FBACK:
214 		/*
215 		 * Check if IDLE since last timeout and recv rate is less than
216 		 * 4 packets per RTT
217 		 */
218 		if (!hctx->ccid3hctx_idle ||
219 		    (hctx->ccid3hctx_x_recv >=
220 		     4 * usecs_div(hctx->ccid3hctx_s, hctx->ccid3hctx_rtt))) {
221 			ccid3_pr_debug("%s, sk=%p, state=%s, not idle\n",
222 				       dccp_role(sk), sk,
223 				       ccid3_tx_state_name(hctx->ccid3hctx_state));
224 			/* Halve sending rate */
225 
226 			/*  If (X_calc > 2 * X_recv)
227 			 *    X_recv = max(X_recv / 2, s / (2 * t_mbi));
228 			 *  Else
229 			 *    X_recv = X_calc / 4;
230 			 */
231 			BUG_ON(hctx->ccid3hctx_p >= TFRC_SMALLEST_P &&
232 			       hctx->ccid3hctx_x_calc == 0);
233 
234 			/* check also if p is zero -> x_calc is infinity? */
235 			if (hctx->ccid3hctx_p < TFRC_SMALLEST_P ||
236 			    hctx->ccid3hctx_x_calc > 2 * hctx->ccid3hctx_x_recv)
237 				hctx->ccid3hctx_x_recv = max_t(u32, hctx->ccid3hctx_x_recv / 2,
238 								    hctx->ccid3hctx_s / (2 * TFRC_MAX_BACK_OFF_TIME));
239 			else
240 				hctx->ccid3hctx_x_recv = hctx->ccid3hctx_x_calc / 4;
241 
242 			/* Update sending rate */
243 			ccid3_hc_tx_update_x(sk);
244 		}
245 		/*
246 		 * Schedule no feedback timer to expire in
247 		 * max(4 * R, 2 * s / X)
248 		 */
249 		next_tmout = max_t(u32, hctx->ccid3hctx_t_rto,
250 					2 * usecs_div(hctx->ccid3hctx_s,
251 						      hctx->ccid3hctx_x));
252 		break;
253 	default:
254 		printk(KERN_CRIT "%s: %s, sk=%p, Illegal state (%d)!\n",
255 		       __FUNCTION__, dccp_role(sk), sk, hctx->ccid3hctx_state);
256 		dump_stack();
257 		goto out;
258 	}
259 
260 	sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
261 		      jiffies + max_t(u32, 1, usecs_to_jiffies(next_tmout)));
262 	hctx->ccid3hctx_idle = 1;
263 out:
264 	bh_unlock_sock(sk);
265 	sock_put(sk);
266 }
267 
268 static int ccid3_hc_tx_send_packet(struct sock *sk,
269 				   struct sk_buff *skb, int len)
270 {
271 	struct dccp_sock *dp = dccp_sk(sk);
272 	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
273 	struct dccp_tx_hist_entry *new_packet;
274 	struct timeval now;
275 	long delay;
276 	int rc = -ENOTCONN;
277 
278 	BUG_ON(hctx == NULL || hctx->ccid3hctx_state == TFRC_SSTATE_TERM);
279 
280 	/* Check if pure ACK or Terminating*/
281 	/*
282 	 * XXX: We only call this function for DATA and DATAACK, on, these
283 	 * packets can have zero length, but why the comment about "pure ACK"?
284 	 */
285 	if (unlikely(len == 0))
286 		goto out;
287 
288 	/* See if last packet allocated was not sent */
289 	new_packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist);
290 	if (new_packet == NULL || new_packet->dccphtx_sent) {
291 		new_packet = dccp_tx_hist_entry_new(ccid3_tx_hist,
292 						    SLAB_ATOMIC);
293 
294 		rc = -ENOBUFS;
295 		if (unlikely(new_packet == NULL)) {
296 			LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, not enough "
297 				       "mem to add to history, send refused\n",
298 				       __FUNCTION__, dccp_role(sk), sk);
299 			goto out;
300 		}
301 
302 		dccp_tx_hist_add_entry(&hctx->ccid3hctx_hist, new_packet);
303 	}
304 
305 	dccp_timestamp(sk, &now);
306 
307 	switch (hctx->ccid3hctx_state) {
308 	case TFRC_SSTATE_NO_SENT:
309 		sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
310 			       jiffies + usecs_to_jiffies(TFRC_INITIAL_TIMEOUT));
311 		hctx->ccid3hctx_last_win_count	 = 0;
312 		hctx->ccid3hctx_t_last_win_count = now;
313 		ccid3_hc_tx_set_state(sk, TFRC_SSTATE_NO_FBACK);
314 		hctx->ccid3hctx_t_ipi = TFRC_INITIAL_IPI;
315 
316 		/* Set nominal send time for initial packet */
317 		hctx->ccid3hctx_t_nom = now;
318 		timeval_add_usecs(&hctx->ccid3hctx_t_nom,
319 				  hctx->ccid3hctx_t_ipi);
320 		ccid3_calc_new_delta(hctx);
321 		rc = 0;
322 		break;
323 	case TFRC_SSTATE_NO_FBACK:
324 	case TFRC_SSTATE_FBACK:
325 		delay = (timeval_delta(&now, &hctx->ccid3hctx_t_nom) -
326 		         hctx->ccid3hctx_delta);
327 		delay /= -1000;
328 		/* divide by -1000 is to convert to ms and get sign right */
329 		rc = delay > 0 ? delay : 0;
330 		break;
331 	default:
332 		printk(KERN_CRIT "%s: %s, sk=%p, Illegal state (%d)!\n",
333 		       __FUNCTION__, dccp_role(sk), sk, hctx->ccid3hctx_state);
334 		dump_stack();
335 		rc = -EINVAL;
336 		break;
337 	}
338 
339 	/* Can we send? if so add options and add to packet history */
340 	if (rc == 0) {
341 		dp->dccps_hc_tx_insert_options = 1;
342 		new_packet->dccphtx_ccval =
343 			DCCP_SKB_CB(skb)->dccpd_ccval =
344 				hctx->ccid3hctx_last_win_count;
345 	}
346 out:
347 	return rc;
348 }
349 
350 static void ccid3_hc_tx_packet_sent(struct sock *sk, int more, int len)
351 {
352 	const struct dccp_sock *dp = dccp_sk(sk);
353 	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
354 	struct timeval now;
355 
356 	BUG_ON(hctx == NULL || hctx->ccid3hctx_state == TFRC_SSTATE_TERM);
357 
358 	dccp_timestamp(sk, &now);
359 
360 	/* check if we have sent a data packet */
361 	if (len > 0) {
362 		unsigned long quarter_rtt;
363 		struct dccp_tx_hist_entry *packet;
364 
365 		packet = dccp_tx_hist_head(&hctx->ccid3hctx_hist);
366 		if (unlikely(packet == NULL)) {
367 			LIMIT_NETDEBUG(KERN_WARNING "%s: packet doesn't "
368 				       "exists in history!\n", __FUNCTION__);
369 			return;
370 		}
371 		if (unlikely(packet->dccphtx_sent)) {
372 			LIMIT_NETDEBUG(KERN_WARNING "%s: no unsent packet in "
373 				       "history!\n", __FUNCTION__);
374 			return;
375 		}
376 		packet->dccphtx_tstamp = now;
377 		packet->dccphtx_seqno  = dp->dccps_gss;
378 		/*
379 		 * Check if win_count have changed
380 		 * Algorithm in "8.1. Window Counter Valuer" in
381 		 * draft-ietf-dccp-ccid3-11.txt
382 		 */
383 		quarter_rtt = timeval_delta(&now, &hctx->ccid3hctx_t_last_win_count);
384 		if (likely(hctx->ccid3hctx_rtt > 8))
385 			quarter_rtt /= hctx->ccid3hctx_rtt / 4;
386 
387 		if (quarter_rtt > 0) {
388 			hctx->ccid3hctx_t_last_win_count = now;
389 			hctx->ccid3hctx_last_win_count	 = (hctx->ccid3hctx_last_win_count +
390 							    min_t(unsigned long, quarter_rtt, 5)) % 16;
391 			ccid3_pr_debug("%s, sk=%p, window changed from "
392 				       "%u to %u!\n",
393 				       dccp_role(sk), sk,
394 				       packet->dccphtx_ccval,
395 				       hctx->ccid3hctx_last_win_count);
396 		}
397 
398 		hctx->ccid3hctx_idle = 0;
399 		packet->dccphtx_rtt  = hctx->ccid3hctx_rtt;
400 		packet->dccphtx_sent = 1;
401 	} else
402 		ccid3_pr_debug("%s, sk=%p, seqno=%llu NOT inserted!\n",
403 			       dccp_role(sk), sk, dp->dccps_gss);
404 
405 	switch (hctx->ccid3hctx_state) {
406 	case TFRC_SSTATE_NO_SENT:
407 		/* if first wasn't pure ack */
408 		if (len != 0)
409 			printk(KERN_CRIT "%s: %s, First packet sent is noted "
410 					 "as a data packet\n",
411 			       __FUNCTION__, dccp_role(sk));
412 		return;
413 	case TFRC_SSTATE_NO_FBACK:
414 	case TFRC_SSTATE_FBACK:
415 		if (len > 0) {
416 			hctx->ccid3hctx_t_nom = now;
417 			ccid3_calc_new_t_ipi(hctx);
418 			ccid3_calc_new_delta(hctx);
419 			timeval_add_usecs(&hctx->ccid3hctx_t_nom,
420 					  hctx->ccid3hctx_t_ipi);
421 		}
422 		break;
423 	default:
424 		printk(KERN_CRIT "%s: %s, sk=%p, Illegal state (%d)!\n",
425 		       __FUNCTION__, dccp_role(sk), sk, hctx->ccid3hctx_state);
426 		dump_stack();
427 		break;
428 	}
429 }
430 
431 static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb)
432 {
433 	const struct dccp_sock *dp = dccp_sk(sk);
434 	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
435 	struct ccid3_options_received *opt_recv;
436 	struct dccp_tx_hist_entry *packet;
437 	struct timeval now;
438 	unsigned long next_tmout;
439 	u32 t_elapsed;
440 	u32 pinv;
441 	u32 x_recv;
442 	u32 r_sample;
443 
444 	BUG_ON(hctx == NULL || hctx->ccid3hctx_state == TFRC_SSTATE_TERM);
445 
446 	/* we are only interested in ACKs */
447 	if (!(DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK ||
448 	      DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_DATAACK))
449 		return;
450 
451 	opt_recv = &hctx->ccid3hctx_options_received;
452 
453 	t_elapsed = dp->dccps_options_received.dccpor_elapsed_time * 10;
454 	x_recv = opt_recv->ccid3or_receive_rate;
455 	pinv = opt_recv->ccid3or_loss_event_rate;
456 
457 	switch (hctx->ccid3hctx_state) {
458 	case TFRC_SSTATE_NO_SENT:
459 		/* FIXME: what to do here? */
460 		return;
461 	case TFRC_SSTATE_NO_FBACK:
462 	case TFRC_SSTATE_FBACK:
463 		/* Calculate new round trip sample by
464 		 * R_sample = (now - t_recvdata) - t_delay */
465 		/* get t_recvdata from history */
466 		packet = dccp_tx_hist_find_entry(&hctx->ccid3hctx_hist,
467 						 DCCP_SKB_CB(skb)->dccpd_ack_seq);
468 		if (unlikely(packet == NULL)) {
469 			LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, seqno "
470 				       "%llu(%s) does't exist in history!\n",
471 				       __FUNCTION__, dccp_role(sk), sk,
472 			    (unsigned long long)DCCP_SKB_CB(skb)->dccpd_ack_seq,
473 				dccp_packet_name(DCCP_SKB_CB(skb)->dccpd_type));
474 			return;
475 		}
476 
477 		/* Update RTT */
478 		dccp_timestamp(sk, &now);
479 		r_sample = timeval_delta(&now, &packet->dccphtx_tstamp);
480 		if (unlikely(r_sample <= t_elapsed))
481 			LIMIT_NETDEBUG(KERN_WARNING "%s: r_sample=%uus, "
482 				       "t_elapsed=%uus\n",
483 				       __FUNCTION__, r_sample, t_elapsed);
484 		else
485 			r_sample -= t_elapsed;
486 
487 		/* Update RTT estimate by
488 		 * If (No feedback recv)
489 		 *    R = R_sample;
490 		 * Else
491 		 *    R = q * R + (1 - q) * R_sample;
492 		 *
493 		 * q is a constant, RFC 3448 recomments 0.9
494 		 */
495 		if (hctx->ccid3hctx_state == TFRC_SSTATE_NO_FBACK) {
496 			ccid3_hc_tx_set_state(sk, TFRC_SSTATE_FBACK);
497 			hctx->ccid3hctx_rtt = r_sample;
498 		} else
499 			hctx->ccid3hctx_rtt = (hctx->ccid3hctx_rtt * 9) / 10 +
500 					      r_sample / 10;
501 
502 		ccid3_pr_debug("%s, sk=%p, New RTT estimate=%uus, "
503 			       "r_sample=%us\n", dccp_role(sk), sk,
504 			       hctx->ccid3hctx_rtt, r_sample);
505 
506 		/* Update timeout interval */
507 		hctx->ccid3hctx_t_rto = max_t(u32, 4 * hctx->ccid3hctx_rtt,
508 					      USEC_PER_SEC);
509 
510 		/* Update receive rate */
511 		hctx->ccid3hctx_x_recv = x_recv;/* X_recv in bytes per sec */
512 
513 		/* Update loss event rate */
514 		if (pinv == ~0 || pinv == 0)
515 			hctx->ccid3hctx_p = 0;
516 		else {
517 			hctx->ccid3hctx_p = 1000000 / pinv;
518 
519 			if (hctx->ccid3hctx_p < TFRC_SMALLEST_P) {
520 				hctx->ccid3hctx_p = TFRC_SMALLEST_P;
521 				ccid3_pr_debug("%s, sk=%p, Smallest p used!\n",
522 					       dccp_role(sk), sk);
523 			}
524 		}
525 
526 		/* unschedule no feedback timer */
527 		sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
528 
529 		/* Update sending rate */
530 		ccid3_hc_tx_update_x(sk);
531 
532 		/* Update next send time */
533 		timeval_sub_usecs(&hctx->ccid3hctx_t_nom,
534 				  hctx->ccid3hctx_t_ipi);
535 		ccid3_calc_new_t_ipi(hctx);
536 		timeval_add_usecs(&hctx->ccid3hctx_t_nom,
537 				  hctx->ccid3hctx_t_ipi);
538 		ccid3_calc_new_delta(hctx);
539 
540 		/* remove all packets older than the one acked from history */
541 		dccp_tx_hist_purge_older(ccid3_tx_hist,
542 					 &hctx->ccid3hctx_hist, packet);
543 		/*
544 		 * As we have calculated new ipi, delta, t_nom it is possible that
545 		 * we now can send a packet, so wake up dccp_wait_for_ccids.
546 		 */
547 		sk->sk_write_space(sk);
548 
549 		/*
550 		 * Schedule no feedback timer to expire in
551 		 * max(4 * R, 2 * s / X)
552 		 */
553 		next_tmout = max(hctx->ccid3hctx_t_rto,
554 				 2 * usecs_div(hctx->ccid3hctx_s,
555 					       hctx->ccid3hctx_x));
556 
557 		ccid3_pr_debug("%s, sk=%p, Scheduled no feedback timer to "
558 			       "expire in %lu jiffies (%luus)\n",
559 			       dccp_role(sk), sk,
560 			       usecs_to_jiffies(next_tmout), next_tmout);
561 
562 		sk_reset_timer(sk, &hctx->ccid3hctx_no_feedback_timer,
563 			       jiffies + max_t(u32, 1, usecs_to_jiffies(next_tmout)));
564 
565 		/* set idle flag */
566 		hctx->ccid3hctx_idle = 1;
567 		break;
568 	default:
569 		printk(KERN_CRIT "%s: %s, sk=%p, Illegal state (%d)!\n",
570 		       __FUNCTION__, dccp_role(sk), sk, hctx->ccid3hctx_state);
571 		dump_stack();
572 		break;
573 	}
574 }
575 
576 static int ccid3_hc_tx_insert_options(struct sock *sk, struct sk_buff *skb)
577 {
578 	const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
579 
580 	BUG_ON(hctx == NULL);
581 
582 	if (sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN)
583 		DCCP_SKB_CB(skb)->dccpd_ccval = hctx->ccid3hctx_last_win_count;
584 	return 0;
585 }
586 
587 static int ccid3_hc_tx_parse_options(struct sock *sk, unsigned char option,
588 				     unsigned char len, u16 idx,
589 				     unsigned char *value)
590 {
591 	int rc = 0;
592 	const struct dccp_sock *dp = dccp_sk(sk);
593 	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
594 	struct ccid3_options_received *opt_recv;
595 
596 	BUG_ON(hctx == NULL);
597 
598 	opt_recv = &hctx->ccid3hctx_options_received;
599 
600 	if (opt_recv->ccid3or_seqno != dp->dccps_gsr) {
601 		opt_recv->ccid3or_seqno		     = dp->dccps_gsr;
602 		opt_recv->ccid3or_loss_event_rate    = ~0;
603 		opt_recv->ccid3or_loss_intervals_idx = 0;
604 		opt_recv->ccid3or_loss_intervals_len = 0;
605 		opt_recv->ccid3or_receive_rate	     = 0;
606 	}
607 
608 	switch (option) {
609 	case TFRC_OPT_LOSS_EVENT_RATE:
610 		if (unlikely(len != 4)) {
611 			LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, invalid "
612 				       "len for TFRC_OPT_LOSS_EVENT_RATE\n",
613 				       __FUNCTION__, dccp_role(sk), sk);
614 			rc = -EINVAL;
615 		} else {
616 			opt_recv->ccid3or_loss_event_rate = ntohl(*(__be32 *)value);
617 			ccid3_pr_debug("%s, sk=%p, LOSS_EVENT_RATE=%u\n",
618 				       dccp_role(sk), sk,
619 				       opt_recv->ccid3or_loss_event_rate);
620 		}
621 		break;
622 	case TFRC_OPT_LOSS_INTERVALS:
623 		opt_recv->ccid3or_loss_intervals_idx = idx;
624 		opt_recv->ccid3or_loss_intervals_len = len;
625 		ccid3_pr_debug("%s, sk=%p, LOSS_INTERVALS=(%u, %u)\n",
626 			       dccp_role(sk), sk,
627 			       opt_recv->ccid3or_loss_intervals_idx,
628 			       opt_recv->ccid3or_loss_intervals_len);
629 		break;
630 	case TFRC_OPT_RECEIVE_RATE:
631 		if (unlikely(len != 4)) {
632 			LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, invalid "
633 				       "len for TFRC_OPT_RECEIVE_RATE\n",
634 				       __FUNCTION__, dccp_role(sk), sk);
635 			rc = -EINVAL;
636 		} else {
637 			opt_recv->ccid3or_receive_rate = ntohl(*(__be32 *)value);
638 			ccid3_pr_debug("%s, sk=%p, RECEIVE_RATE=%u\n",
639 				       dccp_role(sk), sk,
640 				       opt_recv->ccid3or_receive_rate);
641 		}
642 		break;
643 	}
644 
645 	return rc;
646 }
647 
648 static int ccid3_hc_tx_init(struct ccid *ccid, struct sock *sk)
649 {
650 	struct dccp_sock *dp = dccp_sk(sk);
651 	struct ccid3_hc_tx_sock *hctx = ccid_priv(ccid);
652 
653 	if (dp->dccps_packet_size >= TFRC_MIN_PACKET_SIZE &&
654 	    dp->dccps_packet_size <= TFRC_MAX_PACKET_SIZE)
655 		hctx->ccid3hctx_s = dp->dccps_packet_size;
656 	else
657 		hctx->ccid3hctx_s = TFRC_STD_PACKET_SIZE;
658 
659 	/* Set transmission rate to 1 packet per second */
660 	hctx->ccid3hctx_x     = hctx->ccid3hctx_s;
661 	hctx->ccid3hctx_t_rto = USEC_PER_SEC;
662 	hctx->ccid3hctx_state = TFRC_SSTATE_NO_SENT;
663 	INIT_LIST_HEAD(&hctx->ccid3hctx_hist);
664 
665 	hctx->ccid3hctx_no_feedback_timer.function = ccid3_hc_tx_no_feedback_timer;
666 	hctx->ccid3hctx_no_feedback_timer.data     = (unsigned long)sk;
667 	init_timer(&hctx->ccid3hctx_no_feedback_timer);
668 
669 	return 0;
670 }
671 
672 static void ccid3_hc_tx_exit(struct sock *sk)
673 {
674 	struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
675 
676 	BUG_ON(hctx == NULL);
677 
678 	ccid3_hc_tx_set_state(sk, TFRC_SSTATE_TERM);
679 	sk_stop_timer(sk, &hctx->ccid3hctx_no_feedback_timer);
680 
681 	/* Empty packet history */
682 	dccp_tx_hist_purge(ccid3_tx_hist, &hctx->ccid3hctx_hist);
683 }
684 
685 /*
686  * RX Half Connection methods
687  */
688 
689 /* TFRC receiver states */
690 enum ccid3_hc_rx_states {
691        	TFRC_RSTATE_NO_DATA = 1,
692 	TFRC_RSTATE_DATA,
693 	TFRC_RSTATE_TERM    = 127,
694 };
695 
696 #ifdef CCID3_DEBUG
697 static const char *ccid3_rx_state_name(enum ccid3_hc_rx_states state)
698 {
699 	static char *ccid3_rx_state_names[] = {
700 	[TFRC_RSTATE_NO_DATA] = "NO_DATA",
701 	[TFRC_RSTATE_DATA]    = "DATA",
702 	[TFRC_RSTATE_TERM]    = "TERM",
703 	};
704 
705 	return ccid3_rx_state_names[state];
706 }
707 #endif
708 
709 static void ccid3_hc_rx_set_state(struct sock *sk,
710 				  enum ccid3_hc_rx_states state)
711 {
712 	struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
713 	enum ccid3_hc_rx_states oldstate = hcrx->ccid3hcrx_state;
714 
715 	ccid3_pr_debug("%s(%p) %-8.8s -> %s\n",
716 		       dccp_role(sk), sk, ccid3_rx_state_name(oldstate),
717 		       ccid3_rx_state_name(state));
718 	WARN_ON(state == oldstate);
719 	hcrx->ccid3hcrx_state = state;
720 }
721 
722 static void ccid3_hc_rx_send_feedback(struct sock *sk)
723 {
724 	struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
725 	struct dccp_sock *dp = dccp_sk(sk);
726 	struct dccp_rx_hist_entry *packet;
727 	struct timeval now;
728 
729 	ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk);
730 
731 	dccp_timestamp(sk, &now);
732 
733 	switch (hcrx->ccid3hcrx_state) {
734 	case TFRC_RSTATE_NO_DATA:
735 		hcrx->ccid3hcrx_x_recv = 0;
736 		break;
737 	case TFRC_RSTATE_DATA: {
738 		const u32 delta = timeval_delta(&now,
739 					&hcrx->ccid3hcrx_tstamp_last_feedback);
740 		hcrx->ccid3hcrx_x_recv = usecs_div(hcrx->ccid3hcrx_bytes_recv,
741 						   delta);
742 	}
743 		break;
744 	default:
745 		printk(KERN_CRIT "%s: %s, sk=%p, Illegal state (%d)!\n",
746 		       __FUNCTION__, dccp_role(sk), sk, hcrx->ccid3hcrx_state);
747 		dump_stack();
748 		return;
749 	}
750 
751 	packet = dccp_rx_hist_find_data_packet(&hcrx->ccid3hcrx_hist);
752 	if (unlikely(packet == NULL)) {
753 		LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, no data packet "
754 			       "in history!\n",
755 			       __FUNCTION__, dccp_role(sk), sk);
756 		return;
757 	}
758 
759 	hcrx->ccid3hcrx_tstamp_last_feedback = now;
760 	hcrx->ccid3hcrx_last_counter	     = packet->dccphrx_ccval;
761 	hcrx->ccid3hcrx_seqno_last_counter   = packet->dccphrx_seqno;
762 	hcrx->ccid3hcrx_bytes_recv	     = 0;
763 
764 	/* Convert to multiples of 10us */
765 	hcrx->ccid3hcrx_elapsed_time =
766 			timeval_delta(&now, &packet->dccphrx_tstamp) / 10;
767 	if (hcrx->ccid3hcrx_p == 0)
768 		hcrx->ccid3hcrx_pinv = ~0;
769 	else
770 		hcrx->ccid3hcrx_pinv = 1000000 / hcrx->ccid3hcrx_p;
771 	dp->dccps_hc_rx_insert_options = 1;
772 	dccp_send_ack(sk);
773 }
774 
775 static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
776 {
777 	const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
778 	__be32 x_recv, pinv;
779 
780 	BUG_ON(hcrx == NULL);
781 
782 	if (!(sk->sk_state == DCCP_OPEN || sk->sk_state == DCCP_PARTOPEN))
783 		return 0;
784 
785 	DCCP_SKB_CB(skb)->dccpd_ccval = hcrx->ccid3hcrx_last_counter;
786 
787 	if (dccp_packet_without_ack(skb))
788 		return 0;
789 
790 	x_recv = htonl(hcrx->ccid3hcrx_x_recv);
791 	pinv   = htonl(hcrx->ccid3hcrx_pinv);
792 
793 	if ((hcrx->ccid3hcrx_elapsed_time != 0 &&
794 	     dccp_insert_option_elapsed_time(sk, skb,
795 					     hcrx->ccid3hcrx_elapsed_time)) ||
796 	    dccp_insert_option_timestamp(sk, skb) ||
797 	    dccp_insert_option(sk, skb, TFRC_OPT_LOSS_EVENT_RATE,
798 		    	       &pinv, sizeof(pinv)) ||
799 	    dccp_insert_option(sk, skb, TFRC_OPT_RECEIVE_RATE,
800 		    	       &x_recv, sizeof(x_recv)))
801 		return -1;
802 
803 	return 0;
804 }
805 
806 /* calculate first loss interval
807  *
808  * returns estimated loss interval in usecs */
809 
810 static u32 ccid3_hc_rx_calc_first_li(struct sock *sk)
811 {
812 	struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
813 	struct dccp_rx_hist_entry *entry, *next, *tail = NULL;
814 	u32 rtt, delta, x_recv, fval, p, tmp2;
815 	struct timeval tstamp = { 0, };
816 	int interval = 0;
817 	int win_count = 0;
818 	int step = 0;
819 	u64 tmp1;
820 
821 	list_for_each_entry_safe(entry, next, &hcrx->ccid3hcrx_hist,
822 				 dccphrx_node) {
823 		if (dccp_rx_hist_entry_data_packet(entry)) {
824 			tail = entry;
825 
826 			switch (step) {
827 			case 0:
828 				tstamp	  = entry->dccphrx_tstamp;
829 				win_count = entry->dccphrx_ccval;
830 				step = 1;
831 				break;
832 			case 1:
833 				interval = win_count - entry->dccphrx_ccval;
834 				if (interval < 0)
835 					interval += TFRC_WIN_COUNT_LIMIT;
836 				if (interval > 4)
837 					goto found;
838 				break;
839 			}
840 		}
841 	}
842 
843 	if (unlikely(step == 0)) {
844 		LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, packet history "
845 			       "contains no data packets!\n",
846 			       __FUNCTION__, dccp_role(sk), sk);
847 		return ~0;
848 	}
849 
850 	if (unlikely(interval == 0)) {
851 		LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, Could not find a "
852 			       "win_count interval > 0. Defaulting to 1\n",
853 			       __FUNCTION__, dccp_role(sk), sk);
854 		interval = 1;
855 	}
856 found:
857 	rtt = timeval_delta(&tstamp, &tail->dccphrx_tstamp) * 4 / interval;
858 	ccid3_pr_debug("%s, sk=%p, approximated RTT to %uus\n",
859 		       dccp_role(sk), sk, rtt);
860 	if (rtt == 0)
861 		rtt = 1;
862 
863 	dccp_timestamp(sk, &tstamp);
864 	delta = timeval_delta(&tstamp, &hcrx->ccid3hcrx_tstamp_last_feedback);
865 	x_recv = usecs_div(hcrx->ccid3hcrx_bytes_recv, delta);
866 
867 	tmp1 = (u64)x_recv * (u64)rtt;
868 	do_div(tmp1,10000000);
869 	tmp2 = (u32)tmp1;
870 	fval = (hcrx->ccid3hcrx_s * 100000) / tmp2;
871 	/* do not alter order above or you will get overflow on 32 bit */
872 	p = tfrc_calc_x_reverse_lookup(fval);
873 	ccid3_pr_debug("%s, sk=%p, receive rate=%u bytes/s, implied "
874 		       "loss rate=%u\n", dccp_role(sk), sk, x_recv, p);
875 
876 	if (p == 0)
877 		return ~0;
878 	else
879 		return 1000000 / p;
880 }
881 
882 static void ccid3_hc_rx_update_li(struct sock *sk, u64 seq_loss, u8 win_loss)
883 {
884 	struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
885 
886 	if (seq_loss != DCCP_MAX_SEQNO + 1 &&
887 	    list_empty(&hcrx->ccid3hcrx_li_hist)) {
888 		struct dccp_li_hist_entry *li_tail;
889 
890 		li_tail = dccp_li_hist_interval_new(ccid3_li_hist,
891 						    &hcrx->ccid3hcrx_li_hist,
892 						    seq_loss, win_loss);
893 		if (li_tail == NULL)
894 			return;
895 		li_tail->dccplih_interval = ccid3_hc_rx_calc_first_li(sk);
896 	} else
897 		    LIMIT_NETDEBUG(KERN_WARNING "%s: FIXME: find end of "
898 				   "interval\n", __FUNCTION__);
899 }
900 
901 static void ccid3_hc_rx_detect_loss(struct sock *sk)
902 {
903 	struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
904 	u8 win_loss;
905 	const u64 seq_loss = dccp_rx_hist_detect_loss(&hcrx->ccid3hcrx_hist,
906 						      &hcrx->ccid3hcrx_li_hist,
907 						      &win_loss);
908 
909 	ccid3_hc_rx_update_li(sk, seq_loss, win_loss);
910 }
911 
912 static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
913 {
914 	struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
915 	const struct dccp_options_received *opt_recv;
916 	struct dccp_rx_hist_entry *packet;
917 	struct timeval now;
918 	u8 win_count;
919 	u32 p_prev, r_sample, t_elapsed;
920 	int ins;
921 
922 	BUG_ON(hcrx == NULL ||
923 	       !(hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA ||
924 		 hcrx->ccid3hcrx_state == TFRC_RSTATE_DATA));
925 
926 	opt_recv = &dccp_sk(sk)->dccps_options_received;
927 
928 	switch (DCCP_SKB_CB(skb)->dccpd_type) {
929 	case DCCP_PKT_ACK:
930 		if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
931 			return;
932 	case DCCP_PKT_DATAACK:
933 		if (opt_recv->dccpor_timestamp_echo == 0)
934 			break;
935 		p_prev = hcrx->ccid3hcrx_rtt;
936 		dccp_timestamp(sk, &now);
937 		timeval_sub_usecs(&now, opt_recv->dccpor_timestamp_echo * 10);
938 		r_sample = timeval_usecs(&now);
939 		t_elapsed = opt_recv->dccpor_elapsed_time * 10;
940 
941 		if (unlikely(r_sample <= t_elapsed))
942 			LIMIT_NETDEBUG(KERN_WARNING "%s: r_sample=%uus, "
943 				       "t_elapsed=%uus\n",
944 				       __FUNCTION__, r_sample, t_elapsed);
945 		else
946 			r_sample -= t_elapsed;
947 
948 		if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
949 			hcrx->ccid3hcrx_rtt = r_sample;
950 		else
951 			hcrx->ccid3hcrx_rtt = (hcrx->ccid3hcrx_rtt * 9) / 10 +
952 					      r_sample / 10;
953 
954 		if (p_prev != hcrx->ccid3hcrx_rtt)
955 			ccid3_pr_debug("%s, New RTT=%luus, elapsed time=%u\n",
956 				       dccp_role(sk), hcrx->ccid3hcrx_rtt,
957 				       opt_recv->dccpor_elapsed_time);
958 		break;
959 	case DCCP_PKT_DATA:
960 		break;
961 	default: /* We're not interested in other packet types, move along */
962 		return;
963 	}
964 
965 	packet = dccp_rx_hist_entry_new(ccid3_rx_hist, sk, opt_recv->dccpor_ndp,
966 					skb, SLAB_ATOMIC);
967 	if (unlikely(packet == NULL)) {
968 		LIMIT_NETDEBUG(KERN_WARNING "%s: %s, sk=%p, Not enough mem to "
969 				"add rx packet to history, consider it lost!\n",
970 			       __FUNCTION__, dccp_role(sk), sk);
971 		return;
972 	}
973 
974 	win_count = packet->dccphrx_ccval;
975 
976 	ins = dccp_rx_hist_add_packet(ccid3_rx_hist, &hcrx->ccid3hcrx_hist,
977 				      &hcrx->ccid3hcrx_li_hist, packet);
978 
979 	if (DCCP_SKB_CB(skb)->dccpd_type == DCCP_PKT_ACK)
980 		return;
981 
982 	switch (hcrx->ccid3hcrx_state) {
983 	case TFRC_RSTATE_NO_DATA:
984 		ccid3_pr_debug("%s, sk=%p(%s), skb=%p, sending initial "
985 			       "feedback\n",
986 			       dccp_role(sk), sk,
987 			       dccp_state_name(sk->sk_state), skb);
988 		ccid3_hc_rx_send_feedback(sk);
989 		ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA);
990 		return;
991 	case TFRC_RSTATE_DATA:
992 		hcrx->ccid3hcrx_bytes_recv += skb->len -
993 					      dccp_hdr(skb)->dccph_doff * 4;
994 		if (ins != 0)
995 			break;
996 
997 		dccp_timestamp(sk, &now);
998 		if (timeval_delta(&now, &hcrx->ccid3hcrx_tstamp_last_ack) >=
999 		    hcrx->ccid3hcrx_rtt) {
1000 			hcrx->ccid3hcrx_tstamp_last_ack = now;
1001 			ccid3_hc_rx_send_feedback(sk);
1002 		}
1003 		return;
1004 	default:
1005 		printk(KERN_CRIT "%s: %s, sk=%p, Illegal state (%d)!\n",
1006 		       __FUNCTION__, dccp_role(sk), sk, hcrx->ccid3hcrx_state);
1007 		dump_stack();
1008 		return;
1009 	}
1010 
1011 	/* Dealing with packet loss */
1012 	ccid3_pr_debug("%s, sk=%p(%s), data loss! Reacting...\n",
1013 		       dccp_role(sk), sk, dccp_state_name(sk->sk_state));
1014 
1015 	ccid3_hc_rx_detect_loss(sk);
1016 	p_prev = hcrx->ccid3hcrx_p;
1017 
1018 	/* Calculate loss event rate */
1019 	if (!list_empty(&hcrx->ccid3hcrx_li_hist)) {
1020 		u32 i_mean = dccp_li_hist_calc_i_mean(&hcrx->ccid3hcrx_li_hist);
1021 
1022 		/* Scaling up by 1000000 as fixed decimal */
1023 		if (i_mean != 0)
1024 			hcrx->ccid3hcrx_p = 1000000 / i_mean;
1025 	}
1026 
1027 	if (hcrx->ccid3hcrx_p > p_prev) {
1028 		ccid3_hc_rx_send_feedback(sk);
1029 		return;
1030 	}
1031 }
1032 
1033 static int ccid3_hc_rx_init(struct ccid *ccid, struct sock *sk)
1034 {
1035 	struct dccp_sock *dp = dccp_sk(sk);
1036 	struct ccid3_hc_rx_sock *hcrx = ccid_priv(ccid);
1037 
1038 	ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk);
1039 
1040 	if (dp->dccps_packet_size >= TFRC_MIN_PACKET_SIZE &&
1041 	    dp->dccps_packet_size <= TFRC_MAX_PACKET_SIZE)
1042 		hcrx->ccid3hcrx_s = dp->dccps_packet_size;
1043 	else
1044 		hcrx->ccid3hcrx_s = TFRC_STD_PACKET_SIZE;
1045 
1046 	hcrx->ccid3hcrx_state = TFRC_RSTATE_NO_DATA;
1047 	INIT_LIST_HEAD(&hcrx->ccid3hcrx_hist);
1048 	INIT_LIST_HEAD(&hcrx->ccid3hcrx_li_hist);
1049 	dccp_timestamp(sk, &hcrx->ccid3hcrx_tstamp_last_ack);
1050 	hcrx->ccid3hcrx_tstamp_last_feedback = hcrx->ccid3hcrx_tstamp_last_ack;
1051 	hcrx->ccid3hcrx_rtt = 5000; /* XXX 5ms for now... */
1052 	return 0;
1053 }
1054 
1055 static void ccid3_hc_rx_exit(struct sock *sk)
1056 {
1057 	struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1058 
1059 	BUG_ON(hcrx == NULL);
1060 
1061 	ccid3_hc_rx_set_state(sk, TFRC_RSTATE_TERM);
1062 
1063 	/* Empty packet history */
1064 	dccp_rx_hist_purge(ccid3_rx_hist, &hcrx->ccid3hcrx_hist);
1065 
1066 	/* Empty loss interval history */
1067 	dccp_li_hist_purge(ccid3_li_hist, &hcrx->ccid3hcrx_li_hist);
1068 }
1069 
1070 static void ccid3_hc_rx_get_info(struct sock *sk, struct tcp_info *info)
1071 {
1072 	const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1073 
1074 	/* Listen socks doesn't have a private CCID block */
1075 	if (sk->sk_state == DCCP_LISTEN)
1076 		return;
1077 
1078 	BUG_ON(hcrx == NULL);
1079 
1080 	info->tcpi_ca_state	= hcrx->ccid3hcrx_state;
1081 	info->tcpi_options	|= TCPI_OPT_TIMESTAMPS;
1082 	info->tcpi_rcv_rtt	= hcrx->ccid3hcrx_rtt;
1083 }
1084 
1085 static void ccid3_hc_tx_get_info(struct sock *sk, struct tcp_info *info)
1086 {
1087 	const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
1088 
1089 	/* Listen socks doesn't have a private CCID block */
1090 	if (sk->sk_state == DCCP_LISTEN)
1091 		return;
1092 
1093 	BUG_ON(hctx == NULL);
1094 
1095 	info->tcpi_rto = hctx->ccid3hctx_t_rto;
1096 	info->tcpi_rtt = hctx->ccid3hctx_rtt;
1097 }
1098 
1099 static int ccid3_hc_rx_getsockopt(struct sock *sk, const int optname, int len,
1100 				  u32 __user *optval, int __user *optlen)
1101 {
1102 	const struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
1103 	const void *val;
1104 
1105 	/* Listen socks doesn't have a private CCID block */
1106 	if (sk->sk_state == DCCP_LISTEN)
1107 		return -EINVAL;
1108 
1109 	switch (optname) {
1110 	case DCCP_SOCKOPT_CCID_RX_INFO:
1111 		if (len < sizeof(hcrx->ccid3hcrx_tfrc))
1112 			return -EINVAL;
1113 		len = sizeof(hcrx->ccid3hcrx_tfrc);
1114 		val = &hcrx->ccid3hcrx_tfrc;
1115 		break;
1116 	default:
1117 		return -ENOPROTOOPT;
1118 	}
1119 
1120 	if (put_user(len, optlen) || copy_to_user(optval, val, len))
1121 		return -EFAULT;
1122 
1123 	return 0;
1124 }
1125 
1126 static int ccid3_hc_tx_getsockopt(struct sock *sk, const int optname, int len,
1127 				  u32 __user *optval, int __user *optlen)
1128 {
1129 	const struct ccid3_hc_tx_sock *hctx = ccid3_hc_tx_sk(sk);
1130 	const void *val;
1131 
1132 	/* Listen socks doesn't have a private CCID block */
1133 	if (sk->sk_state == DCCP_LISTEN)
1134 		return -EINVAL;
1135 
1136 	switch (optname) {
1137 	case DCCP_SOCKOPT_CCID_TX_INFO:
1138 		if (len < sizeof(hctx->ccid3hctx_tfrc))
1139 			return -EINVAL;
1140 		len = sizeof(hctx->ccid3hctx_tfrc);
1141 		val = &hctx->ccid3hctx_tfrc;
1142 		break;
1143 	default:
1144 		return -ENOPROTOOPT;
1145 	}
1146 
1147 	if (put_user(len, optlen) || copy_to_user(optval, val, len))
1148 		return -EFAULT;
1149 
1150 	return 0;
1151 }
1152 
1153 static struct ccid_operations ccid3 = {
1154 	.ccid_id		   = 3,
1155 	.ccid_name		   = "ccid3",
1156 	.ccid_owner		   = THIS_MODULE,
1157 	.ccid_hc_tx_obj_size	   = sizeof(struct ccid3_hc_tx_sock),
1158 	.ccid_hc_tx_init	   = ccid3_hc_tx_init,
1159 	.ccid_hc_tx_exit	   = ccid3_hc_tx_exit,
1160 	.ccid_hc_tx_send_packet	   = ccid3_hc_tx_send_packet,
1161 	.ccid_hc_tx_packet_sent	   = ccid3_hc_tx_packet_sent,
1162 	.ccid_hc_tx_packet_recv	   = ccid3_hc_tx_packet_recv,
1163 	.ccid_hc_tx_insert_options = ccid3_hc_tx_insert_options,
1164 	.ccid_hc_tx_parse_options  = ccid3_hc_tx_parse_options,
1165 	.ccid_hc_rx_obj_size	   = sizeof(struct ccid3_hc_rx_sock),
1166 	.ccid_hc_rx_init	   = ccid3_hc_rx_init,
1167 	.ccid_hc_rx_exit	   = ccid3_hc_rx_exit,
1168 	.ccid_hc_rx_insert_options = ccid3_hc_rx_insert_options,
1169 	.ccid_hc_rx_packet_recv	   = ccid3_hc_rx_packet_recv,
1170 	.ccid_hc_rx_get_info	   = ccid3_hc_rx_get_info,
1171 	.ccid_hc_tx_get_info	   = ccid3_hc_tx_get_info,
1172 	.ccid_hc_rx_getsockopt	   = ccid3_hc_rx_getsockopt,
1173 	.ccid_hc_tx_getsockopt	   = ccid3_hc_tx_getsockopt,
1174 };
1175 
1176 module_param(ccid3_debug, int, 0444);
1177 MODULE_PARM_DESC(ccid3_debug, "Enable debug messages");
1178 
1179 static __init int ccid3_module_init(void)
1180 {
1181 	int rc = -ENOBUFS;
1182 
1183 	ccid3_rx_hist = dccp_rx_hist_new("ccid3");
1184 	if (ccid3_rx_hist == NULL)
1185 		goto out;
1186 
1187 	ccid3_tx_hist = dccp_tx_hist_new("ccid3");
1188 	if (ccid3_tx_hist == NULL)
1189 		goto out_free_rx;
1190 
1191 	ccid3_li_hist = dccp_li_hist_new("ccid3");
1192 	if (ccid3_li_hist == NULL)
1193 		goto out_free_tx;
1194 
1195 	rc = ccid_register(&ccid3);
1196 	if (rc != 0)
1197 		goto out_free_loss_interval_history;
1198 out:
1199 	return rc;
1200 
1201 out_free_loss_interval_history:
1202 	dccp_li_hist_delete(ccid3_li_hist);
1203 	ccid3_li_hist = NULL;
1204 out_free_tx:
1205 	dccp_tx_hist_delete(ccid3_tx_hist);
1206 	ccid3_tx_hist = NULL;
1207 out_free_rx:
1208 	dccp_rx_hist_delete(ccid3_rx_hist);
1209 	ccid3_rx_hist = NULL;
1210 	goto out;
1211 }
1212 module_init(ccid3_module_init);
1213 
1214 static __exit void ccid3_module_exit(void)
1215 {
1216 	ccid_unregister(&ccid3);
1217 
1218 	if (ccid3_tx_hist != NULL) {
1219 		dccp_tx_hist_delete(ccid3_tx_hist);
1220 		ccid3_tx_hist = NULL;
1221 	}
1222 	if (ccid3_rx_hist != NULL) {
1223 		dccp_rx_hist_delete(ccid3_rx_hist);
1224 		ccid3_rx_hist = NULL;
1225 	}
1226 	if (ccid3_li_hist != NULL) {
1227 		dccp_li_hist_delete(ccid3_li_hist);
1228 		ccid3_li_hist = NULL;
1229 	}
1230 }
1231 module_exit(ccid3_module_exit);
1232 
1233 MODULE_AUTHOR("Ian McDonald <iam4@cs.waikato.ac.nz>, "
1234 	      "Arnaldo Carvalho de Melo <acme@ghostprotocols.net>");
1235 MODULE_DESCRIPTION("DCCP TFRC CCID3 CCID");
1236 MODULE_LICENSE("GPL");
1237 MODULE_ALIAS("net-dccp-ccid-3");
1238