xref: /freebsd/sys/netpfil/ipfw/dn_aqm_pie.c (revision 6419bb52)
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, pie,
166     CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
167     "PIE");
168 
169 #ifdef SYSCTL_NODE
170 SYSCTL_PROC(_net_inet_ip_dummynet_pie, OID_AUTO, target,
171     CTLTYPE_LONG | CTLFLAG_RW | CTLFLAG_NEEDGIANT, NULL, 0,
172     pie_sysctl_target_tupdate_maxb_handler, "L",
173     "queue target in microsecond");
174 SYSCTL_PROC(_net_inet_ip_dummynet_pie, OID_AUTO, tupdate,
175     CTLTYPE_LONG | CTLFLAG_RW | CTLFLAG_NEEDGIANT, NULL, 0,
176     pie_sysctl_target_tupdate_maxb_handler, "L",
177     "the frequency of drop probability calculation in microsecond");
178 SYSCTL_PROC(_net_inet_ip_dummynet_pie, OID_AUTO, max_burst,
179     CTLTYPE_LONG | CTLFLAG_RW | CTLFLAG_NEEDGIANT, NULL, 0,
180     pie_sysctl_target_tupdate_maxb_handler, "L",
181     "Burst allowance interval in microsecond");
182 
183 SYSCTL_PROC(_net_inet_ip_dummynet_pie, OID_AUTO, max_ecnth,
184     CTLTYPE_LONG | CTLFLAG_RW | CTLFLAG_NEEDGIANT, NULL, 0,
185     pie_sysctl_max_ecnth_handler, "L",
186     "ECN safeguard threshold scaled by 1000");
187 
188 SYSCTL_PROC(_net_inet_ip_dummynet_pie, OID_AUTO, alpha,
189     CTLTYPE_LONG | CTLFLAG_RW | CTLFLAG_NEEDGIANT, NULL, 0,
190     pie_sysctl_alpha_beta_handler, "L",
191     "PIE alpha scaled by 1000");
192 SYSCTL_PROC(_net_inet_ip_dummynet_pie, OID_AUTO, beta,
193     CTLTYPE_LONG | CTLFLAG_RW | CTLFLAG_NEEDGIANT, NULL, 0,
194     pie_sysctl_alpha_beta_handler, "L",
195     "beta scaled by 1000");
196 #endif
197 
198 
199 /*
200  * Callout function for drop probability calculation
201  * This function is called over tupdate ms and takes pointer of PIE
202  * status variables as an argument
203   */
204 static void
205 calculate_drop_prob(void *x)
206 {
207 	int64_t p, prob, oldprob;
208 	struct dn_aqm_pie_parms *pprms;
209 	struct pie_status *pst = (struct pie_status *) x;
210 	int p_isneg;
211 
212 	pprms = pst->parms;
213 	prob = pst->drop_prob;
214 
215 	/* calculate current qdelay using DRE method.
216 	 * If TS is used and no data in the queue, reset current_qdelay
217 	 * as it stays at last value during dequeue process.
218 	*/
219 	if (pprms->flags & PIE_DEPRATEEST_ENABLED)
220 		pst->current_qdelay = ((uint64_t)pst->pq->ni.len_bytes *
221 			pst->avg_dq_time) >> PIE_DQ_THRESHOLD_BITS;
222 	else
223 		if (!pst->pq->ni.len_bytes)
224 			 pst->current_qdelay = 0;
225 
226 	/* calculate drop probability */
227 	p = (int64_t)pprms->alpha *
228 		((int64_t)pst->current_qdelay - (int64_t)pprms->qdelay_ref);
229 	p +=(int64_t) pprms->beta *
230 		((int64_t)pst->current_qdelay - (int64_t)pst->qdelay_old);
231 
232 	/* take absolute value so right shift result is well defined */
233 	p_isneg = p < 0;
234 	if (p_isneg) {
235 		p = -p;
236 	}
237 
238 	/* We PIE_MAX_PROB shift by 12-bits to increase the division precision */
239 	p *= (PIE_MAX_PROB << 12) / AQM_TIME_1S;
240 
241 	/* auto-tune drop probability */
242 	if (prob < (PIE_MAX_PROB / 1000000)) /* 0.000001 */
243 		p >>= 11 + PIE_FIX_POINT_BITS + 12;
244 	else if (prob < (PIE_MAX_PROB / 100000)) /* 0.00001 */
245 		p >>= 9 + PIE_FIX_POINT_BITS + 12;
246 	else if (prob < (PIE_MAX_PROB / 10000)) /* 0.0001 */
247 		p >>= 7 + PIE_FIX_POINT_BITS + 12;
248 	else if (prob < (PIE_MAX_PROB / 1000)) /* 0.001 */
249 		p >>= 5 + PIE_FIX_POINT_BITS + 12;
250 	else if (prob < (PIE_MAX_PROB / 100)) /* 0.01 */
251 		p >>= 3 + PIE_FIX_POINT_BITS + 12;
252 	else if (prob < (PIE_MAX_PROB / 10)) /* 0.1 */
253 		p >>= 1 + PIE_FIX_POINT_BITS + 12;
254 	else
255 		p >>= PIE_FIX_POINT_BITS + 12;
256 
257 	oldprob = prob;
258 
259 	if (p_isneg) {
260 		prob = prob - p;
261 
262 		/* check for multiplication underflow */
263 		if (prob > oldprob) {
264 			prob= 0;
265 			D("underflow");
266 		}
267 	} else {
268 		/* Cap Drop adjustment */
269 		if ((pprms->flags & PIE_CAPDROP_ENABLED) &&
270 		    prob >= PIE_MAX_PROB / 10 &&
271 		    p > PIE_MAX_PROB / 50 ) {
272 			p = PIE_MAX_PROB / 50;
273 		}
274 
275 		prob = prob + p;
276 
277 		/* check for multiplication overflow */
278 		if (prob<oldprob) {
279 			D("overflow");
280 			prob= PIE_MAX_PROB;
281 		}
282 	}
283 
284 	/*
285 	 * decay the drop probability exponentially
286 	 * and restrict it to range 0 to PIE_MAX_PROB
287 	 */
288 	if (prob < 0) {
289 		prob = 0;
290 	} else {
291 		if (pst->current_qdelay == 0 && pst->qdelay_old == 0) {
292 			/* 0.98 ~= 1- 1/64 */
293 			prob = prob - (prob >> 6);
294 		}
295 
296 		if (prob > PIE_MAX_PROB) {
297 			prob = PIE_MAX_PROB;
298 		}
299 	}
300 
301 	pst->drop_prob = prob;
302 
303 	/* store current queue delay value in old queue delay*/
304 	pst->qdelay_old = pst->current_qdelay;
305 
306 	/* update burst allowance */
307 	if ((pst->sflags & PIE_ACTIVE) && pst->burst_allowance>0) {
308 
309 		if (pst->burst_allowance > pprms->tupdate )
310 			pst->burst_allowance -= pprms->tupdate;
311 		else
312 			pst->burst_allowance = 0;
313 	}
314 
315 	/* reschedule calculate_drop_prob function */
316 	if (pst->sflags & PIE_ACTIVE)
317 		callout_reset_sbt(&pst->aqm_pie_callout,
318 			(uint64_t)pprms->tupdate * SBT_1US, 0, calculate_drop_prob, pst, 0);
319 
320 	mtx_unlock(&pst->lock_mtx);
321 }
322 
323 /*
324  * Extract a packet from the head of queue 'q'
325  * Return a packet or NULL if the queue is empty.
326  * If getts is set, also extract packet's timestamp from mtag.
327  */
328 static struct mbuf *
329 pie_extract_head(struct dn_queue *q, aqm_time_t *pkt_ts, int getts)
330 {
331 	struct m_tag *mtag;
332 	struct mbuf *m = q->mq.head;
333 
334 	if (m == NULL)
335 		return m;
336 	q->mq.head = m->m_nextpkt;
337 
338 	/* Update stats */
339 	update_stats(q, -m->m_pkthdr.len, 0);
340 
341 	if (q->ni.length == 0) /* queue is now idle */
342 			q->q_time = dn_cfg.curr_time;
343 
344 	if (getts) {
345 		/* extract packet TS*/
346 		mtag = m_tag_locate(m, MTAG_ABI_COMPAT, DN_AQM_MTAG_TS, NULL);
347 		if (mtag == NULL) {
348 			D("PIE timestamp mtag not found!");
349 			*pkt_ts = 0;
350 		} else {
351 			*pkt_ts = *(aqm_time_t *)(mtag + 1);
352 			m_tag_delete(m,mtag);
353 		}
354 	}
355 	return m;
356 }
357 
358 /*
359  * Initiate PIE  variable and optionally activate it
360  */
361 __inline static void
362 init_activate_pie(struct pie_status *pst, int resettimer)
363 {
364 	struct dn_aqm_pie_parms *pprms;
365 
366 	mtx_lock(&pst->lock_mtx);
367 	pprms = pst->parms;
368 	pst->drop_prob = 0;
369 	pst->qdelay_old = 0;
370 	pst->burst_allowance = pprms->max_burst;
371 	pst->accu_prob = 0;
372 	pst->dq_count = 0;
373 	pst->avg_dq_time = 0;
374 	pst->sflags = PIE_INMEASUREMENT;
375 	pst->measurement_start = AQM_UNOW;
376 
377 	if (resettimer) {
378 		pst->sflags |= PIE_ACTIVE;
379 		callout_reset_sbt(&pst->aqm_pie_callout,
380 			(uint64_t)pprms->tupdate * SBT_1US,
381 			0, calculate_drop_prob, pst, 0);
382 	}
383 	//DX(2, "PIE Activated");
384 	mtx_unlock(&pst->lock_mtx);
385 }
386 
387 /*
388  * Deactivate PIE and stop probe update callout
389  */
390 __inline static void
391 deactivate_pie(struct pie_status *pst)
392 {
393 	mtx_lock(&pst->lock_mtx);
394 	pst->sflags &= ~(PIE_ACTIVE | PIE_INMEASUREMENT);
395 	callout_stop(&pst->aqm_pie_callout);
396 	//D("PIE Deactivated");
397 	mtx_unlock(&pst->lock_mtx);
398 }
399 
400 /*
401  * Dequeue and return a pcaket from queue 'q' or NULL if 'q' is empty.
402  * Also, caculate depature time or queue delay using timestamp
403  */
404 static struct mbuf *
405 aqm_pie_dequeue(struct dn_queue *q)
406 {
407 	struct mbuf *m;
408 	struct dn_flow *ni;	/* stats for scheduler instance */
409 	struct dn_aqm_pie_parms *pprms;
410 	struct pie_status *pst;
411 	aqm_time_t now;
412 	aqm_time_t pkt_ts, dq_time;
413 	int32_t w;
414 
415 	pst  = q->aqm_status;
416 	pprms = pst->parms;
417 	ni = &q->_si->ni;
418 
419 	/*we extarct packet ts only when Departure Rate Estimation dis not used*/
420 	m = pie_extract_head(q, &pkt_ts, !(pprms->flags & PIE_DEPRATEEST_ENABLED));
421 
422 	if (!m || !(pst->sflags & PIE_ACTIVE))
423 		return m;
424 
425 	now = AQM_UNOW;
426 	if (pprms->flags & PIE_DEPRATEEST_ENABLED) {
427 		/* calculate average depature time */
428 		if(pst->sflags & PIE_INMEASUREMENT) {
429 			pst->dq_count += m->m_pkthdr.len;
430 
431 			if (pst->dq_count >= PIE_DQ_THRESHOLD) {
432 				dq_time = now - pst->measurement_start;
433 
434 				/*
435 				 * if we don't have old avg dq_time i.e PIE is (re)initialized,
436 				 * don't use weight to calculate new avg_dq_time
437 				 */
438 				if(pst->avg_dq_time == 0)
439 					pst->avg_dq_time = dq_time;
440 				else {
441 					/*
442 					 * weight = PIE_DQ_THRESHOLD/2^6, but we scaled
443 					 * weight by 2^8. Thus, scaled
444 					 * weight = PIE_DQ_THRESHOLD /2^8
445 					 * */
446 					w = PIE_DQ_THRESHOLD >> 8;
447 					pst->avg_dq_time = (dq_time* w
448 						+ (pst->avg_dq_time * ((1L << 8) - w))) >> 8;
449 					pst->sflags &= ~PIE_INMEASUREMENT;
450 				}
451 			}
452 		}
453 
454 		/*
455 		 * Start new measurment cycle when the queue has
456 		 *  PIE_DQ_THRESHOLD worth of bytes.
457 		 */
458 		if(!(pst->sflags & PIE_INMEASUREMENT) &&
459 			q->ni.len_bytes >= PIE_DQ_THRESHOLD) {
460 			pst->sflags |= PIE_INMEASUREMENT;
461 			pst->measurement_start = now;
462 			pst->dq_count = 0;
463 		}
464 	}
465 	/* Optionally, use packet timestamp to estimate queue delay */
466 	else
467 		pst->current_qdelay = now - pkt_ts;
468 
469 	return m;
470 }
471 
472 /*
473  * Enqueue a packet in q, subject to space and  PIE queue management policy
474  * (whose parameters are in q->fs).
475  * Update stats for the queue and the scheduler.
476  * Return 0 on success, 1 on drop. The packet is consumed anyways.
477  */
478 static int
479 aqm_pie_enqueue(struct dn_queue *q, struct mbuf* m)
480 {
481 	struct dn_fs *f;
482 	uint64_t len;
483 	uint32_t qlen;
484 	struct pie_status *pst;
485 	struct dn_aqm_pie_parms *pprms;
486 	int t;
487 
488 	len = m->m_pkthdr.len;
489 	pst  = q->aqm_status;
490 	if(!pst) {
491 		DX(2, "PIE queue is not initialized\n");
492 		update_stats(q, 0, 1);
493 		FREE_PKT(m);
494 		return 1;
495 	}
496 
497 	f = &(q->fs->fs);
498 	pprms = pst->parms;
499 	t = ENQUE;
500 
501 	/* get current queue length in bytes or packets*/
502 	qlen = (f->flags & DN_QSIZE_BYTES) ?
503 		q->ni.len_bytes : q->ni.length;
504 
505 	/* check for queue size and drop the tail if exceed queue limit*/
506 	if (qlen >= f->qsize)
507 		t = DROP;
508 	/* drop/mark the packet when PIE is active and burst time elapsed */
509 	else if ((pst->sflags & PIE_ACTIVE) && pst->burst_allowance==0
510 			&& drop_early(pst, q->ni.len_bytes) == DROP) {
511 				/*
512 				 * if drop_prob over ECN threshold, drop the packet
513 				 * otherwise mark and enqueue it.
514 				 */
515 				if ((pprms->flags & PIE_ECN_ENABLED) && pst->drop_prob <
516 					(pprms->max_ecnth << (PIE_PROB_BITS - PIE_FIX_POINT_BITS))
517 					&& ecn_mark(m))
518 					t = ENQUE;
519 				else
520 					t = DROP;
521 	}
522 
523 	/* Turn PIE on when 1/3 of the queue is full */
524 	if (!(pst->sflags & PIE_ACTIVE) && qlen >= pst->one_third_q_size) {
525 		init_activate_pie(pst, 1);
526 	}
527 
528 	/*  Reset burst tolerance and optinally turn PIE off*/
529 	if ((pst->sflags & PIE_ACTIVE) && pst->drop_prob == 0 &&
530 		pst->current_qdelay < (pprms->qdelay_ref >> 1) &&
531 		pst->qdelay_old < (pprms->qdelay_ref >> 1)) {
532 
533 			pst->burst_allowance = pprms->max_burst;
534 			if ((pprms->flags & PIE_ON_OFF_MODE_ENABLED) && qlen<=0)
535 				deactivate_pie(pst);
536 	}
537 
538 	/* Timestamp the packet if Departure Rate Estimation is disabled */
539 	if (t != DROP && !(pprms->flags & PIE_DEPRATEEST_ENABLED)) {
540 		/* Add TS to mbuf as a TAG */
541 		struct m_tag *mtag;
542 		mtag = m_tag_locate(m, MTAG_ABI_COMPAT, DN_AQM_MTAG_TS, NULL);
543 		if (mtag == NULL)
544 			mtag = m_tag_alloc(MTAG_ABI_COMPAT, DN_AQM_MTAG_TS,
545 				sizeof(aqm_time_t), M_NOWAIT);
546 		if (mtag == NULL) {
547 			m_freem(m);
548 			t = DROP;
549 		}
550 		*(aqm_time_t *)(mtag + 1) = AQM_UNOW;
551 		m_tag_prepend(m, mtag);
552 	}
553 
554 	if (t != DROP) {
555 		mq_append(&q->mq, m);
556 		update_stats(q, len, 0);
557 		return (0);
558 	} else {
559 		update_stats(q, 0, 1);
560 
561 		/* reset accu_prob after packet drop */
562 		pst->accu_prob = 0;
563 		FREE_PKT(m);
564 		return 1;
565 	}
566 	return 0;
567 }
568 
569 /*
570  * initialize PIE for queue 'q'
571  * First allocate memory for PIE status.
572  */
573 static int
574 aqm_pie_init(struct dn_queue *q)
575 {
576 	struct pie_status *pst;
577 	struct dn_aqm_pie_parms *pprms;
578 	int err = 0;
579 
580 	pprms = q->fs->aqmcfg;
581 
582 	do { /* exit with break when error occurs*/
583 		if (!pprms){
584 			DX(2, "AQM_PIE is not configured");
585 			err = EINVAL;
586 			break;
587 		}
588 
589 		q->aqm_status = malloc(sizeof(struct pie_status),
590 				 M_DUMMYNET, M_NOWAIT | M_ZERO);
591 		if (q->aqm_status == NULL) {
592 			D("cannot allocate PIE private data");
593 			err =  ENOMEM ;
594 			break;
595 		}
596 
597 		pst = q->aqm_status;
598 		/* increase reference count for PIE module */
599 		pie_desc.ref_count++;
600 
601 		pst->pq = q;
602 		pst->parms = pprms;
603 
604 		/* For speed optimization, we caculate 1/3 queue size once here */
605 		// we can use x/3 = (x >>2) + (x >>4) + (x >>7)
606 		pst->one_third_q_size = q->fs->fs.qsize/3;
607 
608 		mtx_init(&pst->lock_mtx, "mtx_pie", NULL, MTX_DEF);
609 		callout_init_mtx(&pst->aqm_pie_callout, &pst->lock_mtx,
610 			CALLOUT_RETURNUNLOCKED);
611 
612 		pst->current_qdelay = 0;
613 		init_activate_pie(pst, !(pprms->flags & PIE_ON_OFF_MODE_ENABLED));
614 
615 		//DX(2, "aqm_PIE_init");
616 
617 	} while(0);
618 
619 	return err;
620 }
621 
622 /*
623  * Callout function to destroy pie mtx and free PIE status memory
624  */
625 static void
626 pie_callout_cleanup(void *x)
627 {
628 	struct pie_status *pst = (struct pie_status *) x;
629 
630 	mtx_unlock(&pst->lock_mtx);
631 	mtx_destroy(&pst->lock_mtx);
632 	free(x, M_DUMMYNET);
633 	DN_BH_WLOCK();
634 	pie_desc.ref_count--;
635 	DN_BH_WUNLOCK();
636 }
637 
638 /*
639  * Clean up PIE status for queue 'q'
640  * Destroy memory allocated for PIE status.
641  */
642 static int
643 aqm_pie_cleanup(struct dn_queue *q)
644 {
645 
646 	if(!q) {
647 		D("q is null");
648 		return 0;
649 	}
650 	struct pie_status *pst  = q->aqm_status;
651 	if(!pst) {
652 		//D("queue is already cleaned up");
653 		return 0;
654 	}
655 	if(!q->fs || !q->fs->aqmcfg) {
656 		D("fs is null or no cfg");
657 		return 1;
658 	}
659 	if (q->fs->aqmfp && q->fs->aqmfp->type !=DN_AQM_PIE) {
660 		D("Not PIE fs (%d)", q->fs->fs.fs_nr);
661 		return 1;
662 	}
663 
664 	/*
665 	 * Free PIE status allocated memory using pie_callout_cleanup() callout
666 	 * function to avoid any potential race.
667 	 * We reset aqm_pie_callout to call pie_callout_cleanup() in next 1um. This
668 	 * stops the scheduled calculate_drop_prob() callout and call pie_callout_cleanup()
669 	 * which does memory freeing.
670 	 */
671 	mtx_lock(&pst->lock_mtx);
672 	callout_reset_sbt(&pst->aqm_pie_callout,
673 		SBT_1US, 0, pie_callout_cleanup, pst, 0);
674 	q->aqm_status = NULL;
675 	mtx_unlock(&pst->lock_mtx);
676 
677 	return 0;
678 }
679 
680 /*
681  * Config PIE parameters
682  * also allocate memory for PIE configurations
683  */
684 static int
685 aqm_pie_config(struct dn_fsk* fs, struct dn_extra_parms *ep, int len)
686 {
687 	struct dn_aqm_pie_parms *pcfg;
688 
689 	int l = sizeof(struct dn_extra_parms);
690 	if (len < l) {
691 		D("invalid sched parms length got %d need %d", len, l);
692 		return EINVAL;
693 	}
694 	/* we free the old cfg because maybe the orignal allocation
695 	 * was used for diffirent AQM type.
696 	 */
697 	if (fs->aqmcfg) {
698 		free(fs->aqmcfg, M_DUMMYNET);
699 		fs->aqmcfg = NULL;
700 	}
701 
702 	fs->aqmcfg = malloc(sizeof(struct dn_aqm_pie_parms),
703 			 M_DUMMYNET, M_NOWAIT | M_ZERO);
704 	if (fs->aqmcfg== NULL) {
705 		D("cannot allocate PIE configuration parameters");
706 		return ENOMEM;
707 	}
708 
709 	/* par array contains pie configuration as follow
710 	 * 0- qdelay_ref,1- tupdate, 2- max_burst
711 	 * 3- max_ecnth, 4- alpha, 5- beta, 6- flags
712 	 */
713 
714 	/* configure PIE parameters */
715 	pcfg = fs->aqmcfg;
716 
717 	if (ep->par[0] < 0)
718 		pcfg->qdelay_ref = pie_sysctl.qdelay_ref * AQM_TIME_1US;
719 	else
720 		pcfg->qdelay_ref = ep->par[0];
721 	if (ep->par[1] < 0)
722 		pcfg->tupdate = pie_sysctl.tupdate * AQM_TIME_1US;
723 	else
724 		pcfg->tupdate = ep->par[1];
725 	if (ep->par[2] < 0)
726 		pcfg->max_burst = pie_sysctl.max_burst * AQM_TIME_1US;
727 	else
728 		pcfg->max_burst = ep->par[2];
729 	if (ep->par[3] < 0)
730 		pcfg->max_ecnth = pie_sysctl.max_ecnth;
731 	else
732 		pcfg->max_ecnth = ep->par[3];
733 	if (ep->par[4] < 0)
734 		pcfg->alpha = pie_sysctl.alpha;
735 	else
736 		pcfg->alpha = ep->par[4];
737 	if (ep->par[5] < 0)
738 		pcfg->beta = pie_sysctl.beta;
739 	else
740 		pcfg->beta = ep->par[5];
741 	if (ep->par[6] < 0)
742 		pcfg->flags = pie_sysctl.flags;
743 	else
744 		pcfg->flags = ep->par[6];
745 
746 	/* bound PIE configurations */
747 	pcfg->qdelay_ref = BOUND_VAR(pcfg->qdelay_ref, 1, 10 * AQM_TIME_1S);
748 	pcfg->tupdate = BOUND_VAR(pcfg->tupdate, 1, 10 * AQM_TIME_1S);
749 	pcfg->max_burst = BOUND_VAR(pcfg->max_burst, 0, 10 * AQM_TIME_1S);
750 	pcfg->max_ecnth = BOUND_VAR(pcfg->max_ecnth, 0, PIE_SCALE);
751 	pcfg->alpha = BOUND_VAR(pcfg->alpha, 0, 7 * PIE_SCALE);
752 	pcfg->beta = BOUND_VAR(pcfg->beta, 0 , 7 * PIE_SCALE);
753 
754 	pie_desc.cfg_ref_count++;
755 	//D("pie cfg_ref_count=%d", pie_desc.cfg_ref_count);
756 	return 0;
757 }
758 
759 /*
760  * Deconfigure PIE and free memory allocation
761  */
762 static int
763 aqm_pie_deconfig(struct dn_fsk* fs)
764 {
765 	if (fs && fs->aqmcfg) {
766 		free(fs->aqmcfg, M_DUMMYNET);
767 		fs->aqmcfg = NULL;
768 		pie_desc.cfg_ref_count--;
769 	}
770 	return 0;
771 }
772 
773 /*
774  * Retrieve PIE configuration parameters.
775  */
776 static int
777 aqm_pie_getconfig (struct dn_fsk *fs, struct dn_extra_parms * ep)
778 {
779 	struct dn_aqm_pie_parms *pcfg;
780 	if (fs->aqmcfg) {
781 		strlcpy(ep->name, pie_desc.name, sizeof(ep->name));
782 		pcfg = fs->aqmcfg;
783 		ep->par[0] = pcfg->qdelay_ref / AQM_TIME_1US;
784 		ep->par[1] = pcfg->tupdate / AQM_TIME_1US;
785 		ep->par[2] = pcfg->max_burst / AQM_TIME_1US;
786 		ep->par[3] = pcfg->max_ecnth;
787 		ep->par[4] = pcfg->alpha;
788 		ep->par[5] = pcfg->beta;
789 		ep->par[6] = pcfg->flags;
790 
791 		return 0;
792 	}
793 	return 1;
794 }
795 
796 static struct dn_aqm pie_desc = {
797 	_SI( .type = )  DN_AQM_PIE,
798 	_SI( .name = )  "PIE",
799 	_SI( .ref_count = )  0,
800 	_SI( .cfg_ref_count = )  0,
801 	_SI( .enqueue = )  aqm_pie_enqueue,
802 	_SI( .dequeue = )  aqm_pie_dequeue,
803 	_SI( .config = )  aqm_pie_config,
804 	_SI( .deconfig = )  aqm_pie_deconfig,
805 	_SI( .getconfig = )  aqm_pie_getconfig,
806 	_SI( .init = )  aqm_pie_init,
807 	_SI( .cleanup = )  aqm_pie_cleanup,
808 };
809 
810 DECLARE_DNAQM_MODULE(dn_aqm_pie, &pie_desc);
811 #endif
812