2  * Codel - The Controlled-Delay Active Queue Management algorithm.
8  * Implemented by Rasool Al-Saadi <ralsaadi@swin.edu.au>
10  * Copyright (C) 2011-2014 Kathleen Nichols <nichols@pollere.com>.
26  *  products derived from this software without specific prior written
30  * software may be distributed under the terms of the GNU General Public
34  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
44  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
89 	cst = q->aqm_status;  in codel_dodequeue()
92 		/* queue is empty - we can't be above target */  in codel_dodequeue()
93 		cst->first_above_time= 0;  in codel_dodequeue()
97 	cprms = q->fs->aqmcfg;  in codel_dodequeue()
100 	 * different AQMs in parallel. One is sojourn-time-based  in codel_dodequeue()
101 	 * and takes effect when the time to send an MTU-sized  in codel_dodequeue()
103 	 * below does this.  The other is backlog-based and takes  in codel_dodequeue()
104 	 * effect when the time to send an MTU-sized packet is >=  in codel_dodequeue()
108 	 * interarrival time (MTU-sized packets arriving spaced  in codel_dodequeue()
112 	sojourn_time = now - pkt_ts;  in codel_dodequeue()
113 	if (sojourn_time < cprms->target || q->ni.len_bytes <= cst->maxpkt_size) {  in codel_dodequeue()
114 		/* went below - stay below for at least interval */  in codel_dodequeue()
115 		cst->first_above_time = 0;  in codel_dodequeue()
117 		if (cst->first_above_time == 0) {  in codel_dodequeue()
120 			cst->first_above_time = now + cprms->interval;  in codel_dodequeue()
121 		} else if (now >= cst->first_above_time) {  in codel_dodequeue()
140 	cst = q->aqm_status;  in codel_dequeue()
141 	cprms = q->fs->aqmcfg;  in codel_dequeue()
145 	if (cst->dropping) {  in codel_dequeue()
147 			/* sojourn time below target - leave dropping state */  in codel_dequeue()
148 			cst->dropping = false;  in codel_dequeue()
157 		while (now >= cst->drop_next_time && cst->dropping) {  in codel_dequeue()
159 			if (cprms->flags & CODEL_ECN_ENABLED && ecn_mark(m)) {  in codel_dequeue()
160 				cst->count++;  in codel_dequeue()
162 				cst->drop_next_time = control_law(cst, cprms,  in codel_dequeue()
163 					cst->drop_next_time);  in codel_dequeue()
174 				cst->dropping = false;  in codel_dequeue()
176 				cst->count++;  in codel_dequeue()
178 				cst->drop_next_time = control_law(cst, cprms,  in codel_dequeue()
179 					cst->drop_next_time);  in codel_dequeue()
190 		if (!(cprms->flags & CODEL_ECN_ENABLED) || !ecn_mark(m)) {  in codel_dequeue()
196 		cst->dropping = true;  in codel_dequeue()
199 		 * below, assume that the drop rate that controlled the  in codel_dequeue()
202 		 * later than the time of the last drop so 'now - drop_next'  in codel_dequeue()
206 		cst->count = (cst->count > 2 && ((aqm_stime_t)now -   in codel_dequeue()
207 			(aqm_stime_t)cst->drop_next_time) < 8* cprms->interval)?  in codel_dequeue()
208 				cst->count - 2 : 1;  in codel_dequeue()
211 		cst->drop_next_time = control_law(cst, cprms, now);  in codel_dequeue()