xref: /freebsd/sys/netpfil/ipfw/dn_aqm_pie.c (revision 3fc36ee018bb836bd1796067cf4ef8683f166ebc)
1 /*
2  * PIE - Proportional Integral controller Enhanced AQM algorithm.
3  *
4  * $FreeBSD$
5  *
6  * Copyright (C) 2016 Centre for Advanced Internet Architectures,
7  *  Swinburne University of Technology, Melbourne, Australia.
8  * Portions of this code were made possible in part by a gift from
9  *  The Comcast Innovation Fund.
10  * Implemented by Rasool Al-Saadi <ralsaadi@swin.edu.au>
11  *
12  * Redistribution and use in source and binary forms, with or without
13  * modification, are permitted provided that the following conditions
14  * are met:
15  * 1. Redistributions of source code must retain the above copyright
16  *    notice, this list of conditions and the following disclaimer.
17  * 2. Redistributions in binary form must reproduce the above copyright
18  *    notice, this list of conditions and the following disclaimer in the
19  *    documentation and/or other materials provided with the distribution.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31  * SUCH DAMAGE.
32  */
33 
34 #include <sys/cdefs.h>
35 #include "opt_inet6.h"
36 
37 #include <sys/param.h>
38 #include <sys/systm.h>
39 #include <sys/malloc.h>
40 #include <sys/mbuf.h>
41 #include <sys/kernel.h>
42 #include <sys/lock.h>
43 #include <sys/module.h>
44 #include <sys/mutex.h>
45 #include <sys/priv.h>
46 #include <sys/proc.h>
47 #include <sys/rwlock.h>
48 #include <sys/socket.h>
49 #include <sys/time.h>
50 #include <sys/sysctl.h>
51 
52 #include <net/if.h>	/* IFNAMSIZ, struct ifaddr, ifq head, lock.h mutex.h */
53 #include <net/netisr.h>
54 #include <net/vnet.h>
55 
56 #include <netinet/in.h>
57 #include <netinet/ip.h>		/* ip_len, ip_off */
58 #include <netinet/ip_var.h>	/* ip_output(), IP_FORWARDING */
59 #include <netinet/ip_fw.h>
60 #include <netinet/ip_dummynet.h>
61 #include <netinet/if_ether.h> /* various ether_* routines */
62 #include <netinet/ip6.h>       /* for ip6_input, ip6_output prototypes */
63 #include <netinet6/ip6_var.h>
64 #include <netpfil/ipfw/dn_heap.h>
65 
66 #ifdef NEW_AQM
67 #include <netpfil/ipfw/ip_fw_private.h>
68 #include <netpfil/ipfw/ip_dn_private.h>
69 #include <netpfil/ipfw/dn_aqm.h>
70 #include <netpfil/ipfw/dn_aqm_pie.h>
71 #include <netpfil/ipfw/dn_sched.h>
72 
73 /* for debugging */
74 #include <sys/syslog.h>
75 
76 static struct dn_aqm pie_desc;
77 
78 /*  PIE defaults
79  * target=15ms, tupdate=15ms, max_burst=150ms,
80  * max_ecnth=0.1, alpha=0.125, beta=1.25,
81  */
82 struct dn_aqm_pie_parms pie_sysctl =
83 	{ 15 * AQM_TIME_1MS,  15 * AQM_TIME_1MS, 150 * AQM_TIME_1MS,
84 	PIE_SCALE/10 , PIE_SCALE * 0.125,  PIE_SCALE * 1.25 ,
85 	PIE_CAPDROP_ENABLED | PIE_DEPRATEEST_ENABLED | PIE_DERAND_ENABLED };
86 
87 static int
88 pie_sysctl_alpha_beta_handler(SYSCTL_HANDLER_ARGS)
89 {
90 	int error;
91 	long  value;
92 
93 	if (!strcmp(oidp->oid_name,"alpha"))
94 		value = pie_sysctl.alpha;
95 	else
96 		value = pie_sysctl.beta;
97 
98 	value = value * 1000 / PIE_SCALE;
99 	error = sysctl_handle_long(oidp, &value, 0, req);
100 	if (error != 0 || req->newptr == NULL)
101 		return (error);
102 	if (value < 1 || value > 7 * PIE_SCALE)
103 		return (EINVAL);
104 	value = (value * PIE_SCALE) / 1000;
105 	if (!strcmp(oidp->oid_name,"alpha"))
106 			pie_sysctl.alpha = value;
107 	else
108 		pie_sysctl.beta = value;
109 	return (0);
110 }
111 
112 static int
113 pie_sysctl_target_tupdate_maxb_handler(SYSCTL_HANDLER_ARGS)
114 {
115 	int error;
116 	long  value;
117 
118 	if (!strcmp(oidp->oid_name,"target"))
119 		value = pie_sysctl.qdelay_ref;
120 	else if (!strcmp(oidp->oid_name,"tupdate"))
121 		value = pie_sysctl.tupdate;
122 	else
123 		value = pie_sysctl.max_burst;
124 
125 	value = value / AQM_TIME_1US;
126 	error = sysctl_handle_long(oidp, &value, 0, req);
127 	if (error != 0 || req->newptr == NULL)
128 		return (error);
129 	if (value < 1 || value > 10 * AQM_TIME_1S)
130 		return (EINVAL);
131 	value = value * AQM_TIME_1US;
132 
133 	if (!strcmp(oidp->oid_name,"target"))
134 		pie_sysctl.qdelay_ref  = value;
135 	else if (!strcmp(oidp->oid_name,"tupdate"))
136 		pie_sysctl.tupdate  = value;
137 	else
138 		pie_sysctl.max_burst = value;
139 	return (0);
140 }
141 
142 static int
143 pie_sysctl_max_ecnth_handler(SYSCTL_HANDLER_ARGS)
144 {
145 	int error;
146 	long  value;
147 
148 	value = pie_sysctl.max_ecnth;
149 	value = value * 1000 / PIE_SCALE;
150 	error = sysctl_handle_long(oidp, &value, 0, req);
151 	if (error != 0 || req->newptr == NULL)
152 		return (error);
153 	if (value < 1 || value > PIE_SCALE)
154 		return (EINVAL);
155 	value = (value * PIE_SCALE) / 1000;
156 	pie_sysctl.max_ecnth = value;
157 	return (0);
158 }
159 
160 /* define PIE sysctl variables */
161 SYSBEGIN(f4)
162 SYSCTL_DECL(_net_inet);
163 SYSCTL_DECL(_net_inet_ip);
164 SYSCTL_DECL(_net_inet_ip_dummynet);
165 static SYSCTL_NODE(_net_inet_ip_dummynet, OID_AUTO,
166 	pie, CTLFLAG_RW, 0, "PIE");
167 
168 #ifdef SYSCTL_NODE
169 SYSCTL_PROC(_net_inet_ip_dummynet_pie, OID_AUTO, target,
170 	CTLTYPE_LONG | CTLFLAG_RW, NULL, 0,
171 	pie_sysctl_target_tupdate_maxb_handler, "L",
172 	"queue target in microsecond");
173 SYSCTL_PROC(_net_inet_ip_dummynet_pie, OID_AUTO, tupdate,
174 	CTLTYPE_LONG | CTLFLAG_RW, NULL, 0,
175 	pie_sysctl_target_tupdate_maxb_handler, "L",
176 	"the frequency of drop probability calculation in microsecond");
177 SYSCTL_PROC(_net_inet_ip_dummynet_pie, OID_AUTO, max_burst,
178 	CTLTYPE_LONG | CTLFLAG_RW, NULL, 0,
179 	pie_sysctl_target_tupdate_maxb_handler, "L",
180 	"Burst allowance interval in microsecond");
181 
182 SYSCTL_PROC(_net_inet_ip_dummynet_pie, OID_AUTO, max_ecnth,
183 	CTLTYPE_LONG | CTLFLAG_RW, NULL, 0,
184 	pie_sysctl_max_ecnth_handler, "L",
185 	"ECN safeguard threshold scaled by 1000");
186 
187 SYSCTL_PROC(_net_inet_ip_dummynet_pie, OID_AUTO, alpha,
188 	CTLTYPE_LONG | CTLFLAG_RW, NULL, 0,
189 	pie_sysctl_alpha_beta_handler, "L",
190 	"PIE alpha scaled by 1000");
191 SYSCTL_PROC(_net_inet_ip_dummynet_pie, OID_AUTO, beta,
192 	CTLTYPE_LONG | CTLFLAG_RW, NULL, 0,
193 	pie_sysctl_alpha_beta_handler, "L",
194 	"beta scaled by 1000");
195 #endif
196 
197 
198 /*
199  * Callout function for drop probability calculation
200  * This function is called over tupdate ms and takes pointer of PIE
201  * status variables as an argument
202   */
203 static void
204 calculate_drop_prob(void *x)
205 {
206 	int64_t p, prob, oldprob;
207 	struct dn_aqm_pie_parms *pprms;
208 	struct pie_status *pst = (struct pie_status *) x;
209 
210 	pprms = pst->parms;
211 	prob = pst->drop_prob;
212 
213 	/* calculate current qdelay */
214 	if (pprms->flags & PIE_DEPRATEEST_ENABLED) {
215 		pst->current_qdelay = ((uint64_t)pst->pq->ni.len_bytes *
216 			pst->avg_dq_time) >> PIE_DQ_THRESHOLD_BITS;
217 	}
218 
219 	/* calculate drop probability */
220 	p = (int64_t)pprms->alpha *
221 		((int64_t)pst->current_qdelay - (int64_t)pprms->qdelay_ref);
222 	p +=(int64_t) pprms->beta *
223 		((int64_t)pst->current_qdelay - (int64_t)pst->qdelay_old);
224 
225 	/* We PIE_MAX_PROB shift by 12-bits to increase the division precision */
226 	p *= (PIE_MAX_PROB << 12) / AQM_TIME_1S;
227 
228 	/* auto-tune drop probability */
229 	if (prob < (PIE_MAX_PROB / 1000000)) /* 0.000001 */
230 		p >>= 11 + PIE_FIX_POINT_BITS + 12;
231 	else if (prob < (PIE_MAX_PROB / 100000)) /* 0.00001 */
232 		p >>= 9 + PIE_FIX_POINT_BITS + 12;
233 	else if (prob < (PIE_MAX_PROB / 10000)) /* 0.0001 */
234 		p >>= 7 + PIE_FIX_POINT_BITS + 12;
235 	else if (prob < (PIE_MAX_PROB / 1000)) /* 0.001 */
236 		p >>= 5 + PIE_FIX_POINT_BITS + 12;
237 	else if (prob < (PIE_MAX_PROB / 100)) /* 0.01 */
238 		p >>= 3 + PIE_FIX_POINT_BITS + 12;
239 	else if (prob < (PIE_MAX_PROB / 10)) /* 0.1 */
240 		p >>= 1 + PIE_FIX_POINT_BITS + 12;
241 	else
242 		p >>= PIE_FIX_POINT_BITS + 12;
243 
244 	oldprob = prob;
245 
246 	/* Cap Drop adjustment */
247 	if ((pprms->flags & PIE_CAPDROP_ENABLED) && prob >= PIE_MAX_PROB / 10
248 		&& p > PIE_MAX_PROB / 50 )
249 			p = PIE_MAX_PROB / 50;
250 
251 	prob = prob + p;
252 
253 	/* decay the drop probability exponentially */
254 	if (pst->current_qdelay == 0 && pst->qdelay_old == 0)
255 		/* 0.98 ~= 1- 1/64 */
256 		prob = prob - (prob >> 6);
257 
258 
259 	/* check for multiplication overflow/underflow */
260 	if (p>0) {
261 		if (prob<oldprob) {
262 			D("overflow");
263 			prob= PIE_MAX_PROB;
264 		}
265 	}
266 	else
267 		if (prob>oldprob) {
268 			prob= 0;
269 			D("underflow");
270 		}
271 
272 	/* make drop probability between 0 and PIE_MAX_PROB*/
273 	if (prob < 0)
274 		prob = 0;
275 	else if (prob > PIE_MAX_PROB)
276 		prob = PIE_MAX_PROB;
277 
278 	pst->drop_prob = prob;
279 
280 	/* store current queue delay value in old queue delay*/
281 	pst->qdelay_old = pst->current_qdelay;
282 
283 	/* update burst allowance */
284 	if ((pst->sflags & PIE_ACTIVE) && pst->burst_allowance>0) {
285 
286 		if (pst->burst_allowance > pprms->tupdate )
287 			pst->burst_allowance -= pprms->tupdate;
288 		else
289 			pst->burst_allowance = 0;
290 	}
291 
292 	/* reschedule calculate_drop_prob function */
293 	if (pst->sflags & PIE_ACTIVE)
294 		callout_reset_sbt(&pst->aqm_pie_callout,
295 			(uint64_t)pprms->tupdate * SBT_1US, 0, calculate_drop_prob, pst, 0);
296 
297 	mtx_unlock(&pst->lock_mtx);
298 }
299 
300 /*
301  * Extract a packet from the head of queue 'q'
302  * Return a packet or NULL if the queue is empty.
303  * If getts is set, also extract packet's timestamp from mtag.
304  */
305 static struct mbuf *
306 pie_extract_head(struct dn_queue *q, aqm_time_t *pkt_ts, int getts)
307 {
308 	struct m_tag *mtag;
309 	struct mbuf *m = q->mq.head;
310 
311 	if (m == NULL)
312 		return m;
313 	q->mq.head = m->m_nextpkt;
314 
315 	/* Update stats */
316 	update_stats(q, -m->m_pkthdr.len, 0);
317 
318 	if (q->ni.length == 0) /* queue is now idle */
319 			q->q_time = dn_cfg.curr_time;
320 
321 	if (getts) {
322 		/* extract packet TS*/
323 		mtag = m_tag_locate(m, MTAG_ABI_COMPAT, DN_AQM_MTAG_TS, NULL);
324 		if (mtag == NULL) {
325 			D("PIE timestamp mtag not found!");
326 			*pkt_ts = 0;
327 		} else {
328 			*pkt_ts = *(aqm_time_t *)(mtag + 1);
329 			m_tag_delete(m,mtag);
330 		}
331 	}
332 	return m;
333 }
334 
335 /*
336  * Initiate PIE  variable and optionally activate it
337  */
338 __inline static void
339 init_activate_pie(struct pie_status *pst, int resettimer)
340 {
341 	struct dn_aqm_pie_parms *pprms;
342 
343 	mtx_lock(&pst->lock_mtx);
344 	pprms = pst->parms;
345 	pst->drop_prob = 0;
346 	pst->qdelay_old = 0;
347 	pst->burst_allowance = pprms->max_burst;
348 	pst->accu_prob = 0;
349 	pst->dq_count = 0;
350 	pst->avg_dq_time = 0;
351 	pst->sflags = PIE_INMEASUREMENT;
352 	pst->measurement_start = AQM_UNOW;
353 
354 	if (resettimer) {
355 		pst->sflags |= PIE_ACTIVE;
356 		callout_reset_sbt(&pst->aqm_pie_callout,
357 			(uint64_t)pprms->tupdate * SBT_1US,
358 			0, calculate_drop_prob, pst, 0);
359 	}
360 	//DX(2, "PIE Activated");
361 	mtx_unlock(&pst->lock_mtx);
362 }
363 
364 /*
365  * Deactivate PIE and stop probe update callout
366  */
367 __inline static void
368 deactivate_pie(struct pie_status *pst)
369 {
370 	mtx_lock(&pst->lock_mtx);
371 	pst->sflags &= ~(PIE_ACTIVE | PIE_INMEASUREMENT);
372 	callout_stop(&pst->aqm_pie_callout);
373 	//D("PIE Deactivated");
374 	mtx_unlock(&pst->lock_mtx);
375 }
376 
377 /*
378  * Dequeue and return a pcaket from queue 'q' or NULL if 'q' is empty.
379  * Also, caculate depature time or queue delay using timestamp
380  */
381 static struct mbuf *
382 aqm_pie_dequeue(struct dn_queue *q)
383 {
384 	struct mbuf *m;
385 	struct dn_flow *ni;	/* stats for scheduler instance */
386 	struct dn_aqm_pie_parms *pprms;
387 	struct pie_status *pst;
388 	aqm_time_t now;
389 	aqm_time_t pkt_ts, dq_time;
390 	int32_t w;
391 
392 	pst  = q->aqm_status;
393 	pprms = pst->parms;
394 	ni = &q->_si->ni;
395 
396 	/*we extarct packet ts only when Departure Rate Estimation dis not used*/
397 	m = pie_extract_head(q, &pkt_ts, !(pprms->flags & PIE_DEPRATEEST_ENABLED));
398 
399 	if (!m || !(pst->sflags & PIE_ACTIVE))
400 		return m;
401 
402 	now = AQM_UNOW;
403 	if (pprms->flags & PIE_DEPRATEEST_ENABLED) {
404 		/* calculate average depature time */
405 		if(pst->sflags & PIE_INMEASUREMENT) {
406 			pst->dq_count += m->m_pkthdr.len;
407 
408 			if (pst->dq_count >= PIE_DQ_THRESHOLD) {
409 				dq_time = now - pst->measurement_start;
410 
411 				/*
412 				 * if we don't have old avg dq_time i.e PIE is (re)initialized,
413 				 * don't use weight to calculate new avg_dq_time
414 				 */
415 				if(pst->avg_dq_time == 0)
416 					pst->avg_dq_time = dq_time;
417 				else {
418 					/*
419 					 * weight = PIE_DQ_THRESHOLD/2^6, but we scaled
420 					 * weight by 2^8. Thus, scaled
421 					 * weight = PIE_DQ_THRESHOLD /2^8
422 					 * */
423 					w = PIE_DQ_THRESHOLD >> 8;
424 					pst->avg_dq_time = (dq_time* w
425 						+ (pst->avg_dq_time * ((1L << 8) - w))) >> 8;
426 					pst->sflags &= ~PIE_INMEASUREMENT;
427 				}
428 			}
429 		}
430 
431 		/*
432 		 * Start new measurment cycle when the queue has
433 		 *  PIE_DQ_THRESHOLD worth of bytes.
434 		 */
435 		if(!(pst->sflags & PIE_INMEASUREMENT) &&
436 			q->ni.len_bytes >= PIE_DQ_THRESHOLD) {
437 			pst->sflags |= PIE_INMEASUREMENT;
438 			pst->measurement_start = now;
439 			pst->dq_count = 0;
440 		}
441 	}
442 	/* Optionally, use packet timestamp to estimate queue delay */
443 	else
444 		pst->current_qdelay = now - pkt_ts;
445 
446 	return m;
447 }
448 
449 /*
450  * Enqueue a packet in q, subject to space and  PIE queue management policy
451  * (whose parameters are in q->fs).
452  * Update stats for the queue and the scheduler.
453  * Return 0 on success, 1 on drop. The packet is consumed anyways.
454  */
455 static int
456 aqm_pie_enqueue(struct dn_queue *q, struct mbuf* m)
457 {
458 	struct dn_fs *f;
459 	uint64_t len;
460 	uint32_t qlen;
461 	struct pie_status *pst;
462 	struct dn_aqm_pie_parms *pprms;
463 	int t;
464 
465 	len = m->m_pkthdr.len;
466 	pst  = q->aqm_status;
467 	if(!pst) {
468 		DX(2, "PIE queue is not initialized\n");
469 		update_stats(q, 0, 1);
470 		FREE_PKT(m);
471 		return 1;
472 	}
473 
474 	f = &(q->fs->fs);
475 	pprms = pst->parms;
476 	t = ENQUE;
477 
478 	/* get current queue length in bytes or packets*/
479 	qlen = (f->flags & DN_QSIZE_BYTES) ?
480 		q->ni.len_bytes : q->ni.length;
481 
482 	/* check for queue size and drop the tail if exceed queue limit*/
483 	if (qlen >= f->qsize)
484 		t = DROP;
485 	/* drop/mark the packet when PIE is active and burst time elapsed */
486 	else if ((pst->sflags & PIE_ACTIVE) && pst->burst_allowance==0
487 			&& drop_early(pst, q->ni.len_bytes) == DROP) {
488 				/*
489 				 * if drop_prob over ECN threshold, drop the packet
490 				 * otherwise mark and enqueue it.
491 				 */
492 				if ((pprms->flags & PIE_ECN_ENABLED) && pst->drop_prob <
493 					(pprms->max_ecnth << (PIE_PROB_BITS - PIE_FIX_POINT_BITS))
494 					&& ecn_mark(m))
495 					t = ENQUE;
496 				else
497 					t = DROP;
498 	}
499 
500 	/* Turn PIE on when 1/3 of the queue is full */
501 	if (!(pst->sflags & PIE_ACTIVE) && qlen >= pst->one_third_q_size) {
502 		init_activate_pie(pst, 1);
503 	}
504 
505 	/*  Reset burst tolerance and optinally turn PIE off*/
506 	if ((pst->sflags & PIE_ACTIVE) && pst->drop_prob == 0 &&
507 		pst->current_qdelay < (pprms->qdelay_ref >> 1) &&
508 		pst->qdelay_old < (pprms->qdelay_ref >> 1)) {
509 
510 			pst->burst_allowance = pprms->max_burst;
511 			if ((pprms->flags & PIE_ON_OFF_MODE_ENABLED) && qlen<=0)
512 				deactivate_pie(pst);
513 	}
514 
515 	/* Timestamp the packet if Departure Rate Estimation is disabled */
516 	if (t != DROP && !(pprms->flags & PIE_DEPRATEEST_ENABLED)) {
517 		/* Add TS to mbuf as a TAG */
518 		struct m_tag *mtag;
519 		mtag = m_tag_locate(m, MTAG_ABI_COMPAT, DN_AQM_MTAG_TS, NULL);
520 		if (mtag == NULL)
521 			mtag = m_tag_alloc(MTAG_ABI_COMPAT, DN_AQM_MTAG_TS,
522 				sizeof(aqm_time_t), M_NOWAIT);
523 		if (mtag == NULL) {
524 			m_freem(m);
525 			t = DROP;
526 		}
527 		*(aqm_time_t *)(mtag + 1) = AQM_UNOW;
528 		m_tag_prepend(m, mtag);
529 	}
530 
531 	if (t != DROP) {
532 		mq_append(&q->mq, m);
533 		update_stats(q, len, 0);
534 		return (0);
535 	} else {
536 		update_stats(q, 0, 1);
537 
538 		/* reset accu_prob after packet drop */
539 		pst->accu_prob = 0;
540 		FREE_PKT(m);
541 		return 1;
542 	}
543 	return 0;
544 }
545 
546 /*
547  * initialize PIE for queue 'q'
548  * First allocate memory for PIE status.
549  */
550 static int
551 aqm_pie_init(struct dn_queue *q)
552 {
553 	struct pie_status *pst;
554 	struct dn_aqm_pie_parms *pprms;
555 	int err = 0;
556 
557 	pprms = q->fs->aqmcfg;
558 
559 	do { /* exit with break when error occurs*/
560 		if (!pprms){
561 			DX(2, "AQM_PIE is not configured");
562 			err = EINVAL;
563 			break;
564 		}
565 
566 		q->aqm_status = malloc(sizeof(struct pie_status),
567 				 M_DUMMYNET, M_NOWAIT | M_ZERO);
568 		if (q->aqm_status == NULL) {
569 			D("cannot allocate PIE private data");
570 			err =  ENOMEM ;
571 			break;
572 		}
573 
574 		pst = q->aqm_status;
575 		/* increase reference count for PIE module */
576 		pie_desc.ref_count++;
577 
578 		pst->pq = q;
579 		pst->parms = pprms;
580 
581 		/* For speed optimization, we caculate 1/3 queue size once here */
582 		// we can use x/3 = (x >>2) + (x >>4) + (x >>7)
583 		pst->one_third_q_size = q->fs->fs.qsize/3;
584 
585 		mtx_init(&pst->lock_mtx, "mtx_pie", NULL, MTX_DEF);
586 		callout_init_mtx(&pst->aqm_pie_callout, &pst->lock_mtx,
587 			CALLOUT_RETURNUNLOCKED);
588 
589 		pst->current_qdelay = 0;
590 		init_activate_pie(pst, !(pprms->flags & PIE_ON_OFF_MODE_ENABLED));
591 
592 		//DX(2, "aqm_PIE_init");
593 
594 	} while(0);
595 
596 	return err;
597 }
598 
599 /*
600  * Callout function to destroy pie mtx and free PIE status memory
601  */
602 static void
603 pie_callout_cleanup(void *x)
604 {
605 	struct pie_status *pst = (struct pie_status *) x;
606 
607 	mtx_unlock(&pst->lock_mtx);
608 	mtx_destroy(&pst->lock_mtx);
609 	free(x, M_DUMMYNET);
610 	DN_BH_WLOCK();
611 	pie_desc.ref_count--;
612 	DN_BH_WUNLOCK();
613 }
614 
615 /*
616  * Clean up PIE status for queue 'q'
617  * Destroy memory allocated for PIE status.
618  */
619 static int
620 aqm_pie_cleanup(struct dn_queue *q)
621 {
622 
623 	if(!q) {
624 		D("q is null");
625 		return 0;
626 	}
627 	struct pie_status *pst  = q->aqm_status;
628 	if(!pst) {
629 		//D("queue is already cleaned up");
630 		return 0;
631 	}
632 	if(!q->fs || !q->fs->aqmcfg) {
633 		D("fs is null or no cfg");
634 		return 1;
635 	}
636 	if (q->fs->aqmfp && q->fs->aqmfp->type !=DN_AQM_PIE) {
637 		D("Not PIE fs (%d)", q->fs->fs.fs_nr);
638 		return 1;
639 	}
640 
641 	/*
642 	 * Free PIE status allocated memory using pie_callout_cleanup() callout
643 	 * function to avoid any potential race.
644 	 * We reset aqm_pie_callout to call pie_callout_cleanup() in next 1um. This
645 	 * stops the scheduled calculate_drop_prob() callout and call pie_callout_cleanup()
646 	 * which does memory freeing.
647 	 */
648 	mtx_lock(&pst->lock_mtx);
649 	callout_reset_sbt(&pst->aqm_pie_callout,
650 		SBT_1US, 0, pie_callout_cleanup, pst, 0);
651 	q->aqm_status = NULL;
652 	mtx_unlock(&pst->lock_mtx);
653 
654 	return 0;
655 }
656 
657 /*
658  * Config PIE parameters
659  * also allocate memory for PIE configurations
660  */
661 static int
662 aqm_pie_config(struct dn_fsk* fs, struct dn_extra_parms *ep, int len)
663 {
664 	struct dn_aqm_pie_parms *pcfg;
665 
666 	int l = sizeof(struct dn_extra_parms);
667 	if (len < l) {
668 		D("invalid sched parms length got %d need %d", len, l);
669 		return EINVAL;
670 	}
671 	/* we free the old cfg because maybe the orignal allocation
672 	 * was used for diffirent AQM type.
673 	 */
674 	if (fs->aqmcfg) {
675 		free(fs->aqmcfg, M_DUMMYNET);
676 		fs->aqmcfg = NULL;
677 	}
678 
679 	fs->aqmcfg = malloc(sizeof(struct dn_aqm_pie_parms),
680 			 M_DUMMYNET, M_NOWAIT | M_ZERO);
681 	if (fs->aqmcfg== NULL) {
682 		D("cannot allocate PIE configuration parameters");
683 		return ENOMEM;
684 	}
685 
686 	/* par array contains pie configuration as follow
687 	 * 0- qdelay_ref,1- tupdate, 2- max_burst
688 	 * 3- max_ecnth, 4- alpha, 5- beta, 6- flags
689 	 */
690 
691 	/* configure PIE parameters */
692 	pcfg = fs->aqmcfg;
693 
694 	if (ep->par[0] < 0)
695 		pcfg->qdelay_ref = pie_sysctl.qdelay_ref * AQM_TIME_1US;
696 	else
697 		pcfg->qdelay_ref = ep->par[0];
698 	if (ep->par[1] < 0)
699 		pcfg->tupdate = pie_sysctl.tupdate * AQM_TIME_1US;
700 	else
701 		pcfg->tupdate = ep->par[1];
702 	if (ep->par[2] < 0)
703 		pcfg->max_burst = pie_sysctl.max_burst * AQM_TIME_1US;
704 	else
705 		pcfg->max_burst = ep->par[2];
706 	if (ep->par[3] < 0)
707 		pcfg->max_ecnth = pie_sysctl.max_ecnth;
708 	else
709 		pcfg->max_ecnth = ep->par[3];
710 	if (ep->par[4] < 0)
711 		pcfg->alpha = pie_sysctl.alpha;
712 	else
713 		pcfg->alpha = ep->par[4];
714 	if (ep->par[5] < 0)
715 		pcfg->beta = pie_sysctl.beta;
716 	else
717 		pcfg->beta = ep->par[5];
718 	if (ep->par[6] < 0)
719 		pcfg->flags = pie_sysctl.flags;
720 	else
721 		pcfg->flags = ep->par[6];
722 
723 	/* bound PIE configurations */
724 	pcfg->qdelay_ref = BOUND_VAR(pcfg->qdelay_ref, 1, 10 * AQM_TIME_1S);
725 	pcfg->tupdate = BOUND_VAR(pcfg->tupdate, 1, 10 * AQM_TIME_1S);
726 	pcfg->max_burst = BOUND_VAR(pcfg->max_burst, 0, 10 * AQM_TIME_1S);
727 	pcfg->max_ecnth = BOUND_VAR(pcfg->max_ecnth, 0, PIE_SCALE);
728 	pcfg->alpha = BOUND_VAR(pcfg->alpha, 0, 7 * PIE_SCALE);
729 	pcfg->beta = BOUND_VAR(pcfg->beta, 0 , 7 * PIE_SCALE);
730 
731 	pie_desc.cfg_ref_count++;
732 	//D("pie cfg_ref_count=%d", pie_desc.cfg_ref_count);
733 	return 0;
734 }
735 
736 /*
737  * Deconfigure PIE and free memory allocation
738  */
739 static int
740 aqm_pie_deconfig(struct dn_fsk* fs)
741 {
742 	if (fs && fs->aqmcfg) {
743 		free(fs->aqmcfg, M_DUMMYNET);
744 		fs->aqmcfg = NULL;
745 		pie_desc.cfg_ref_count--;
746 	}
747 	return 0;
748 }
749 
750 /*
751  * Retrieve PIE configuration parameters.
752  */
753 static int
754 aqm_pie_getconfig (struct dn_fsk *fs, struct dn_extra_parms * ep)
755 {
756 	struct dn_aqm_pie_parms *pcfg;
757 	if (fs->aqmcfg) {
758 		strcpy(ep->name, pie_desc.name);
759 		pcfg = fs->aqmcfg;
760 		ep->par[0] = pcfg->qdelay_ref / AQM_TIME_1US;
761 		ep->par[1] = pcfg->tupdate / AQM_TIME_1US;
762 		ep->par[2] = pcfg->max_burst / AQM_TIME_1US;
763 		ep->par[3] = pcfg->max_ecnth;
764 		ep->par[4] = pcfg->alpha;
765 		ep->par[5] = pcfg->beta;
766 		ep->par[6] = pcfg->flags;
767 
768 		return 0;
769 	}
770 	return 1;
771 }
772 
773 static struct dn_aqm pie_desc = {
774 	_SI( .type = )  DN_AQM_PIE,
775 	_SI( .name = )  "PIE",
776 	_SI( .ref_count = )  0,
777 	_SI( .cfg_ref_count = )  0,
778 	_SI( .enqueue = )  aqm_pie_enqueue,
779 	_SI( .dequeue = )  aqm_pie_dequeue,
780 	_SI( .config = )  aqm_pie_config,
781 	_SI( .deconfig = )  aqm_pie_deconfig,
782 	_SI( .getconfig = )  aqm_pie_getconfig,
783 	_SI( .init = )  aqm_pie_init,
784 	_SI( .cleanup = )  aqm_pie_cleanup,
785 };
786 
787 DECLARE_DNAQM_MODULE(dn_aqm_pie, &pie_desc);
788 #endif
789