1 /*
2  * iperf, Copyright (c) 2014, The Regents of the University of
3  * California, through Lawrence Berkeley National Laboratory (subject
4  * to receipt of any required approvals from the U.S. Dept. of
5  * Energy).  All rights reserved.
6  *
7  * If you have questions about your rights to use or distribute this
8  * software, please contact Berkeley Lab's Technology Transfer
9  * Department at TTD@lbl.gov.
10  *
11  * NOTICE.  This software is owned by the U.S. Department of Energy.
12  * As such, the U.S. Government has been granted for itself and others
13  * acting on its behalf a paid-up, nonexclusive, irrevocable,
14  * worldwide license in the Software to reproduce, prepare derivative
15  * works, and perform publicly and display publicly.  Beginning five
16  * (5) years after the date permission to assert copyright is obtained
17  * from the U.S. Department of Energy, and subject to any subsequent
18  * five (5) year renewals, the U.S. Government is granted for itself
19  * and others acting on its behalf a paid-up, nonexclusive,
20  * irrevocable, worldwide license in the Software to reproduce,
21  * prepare derivative works, distribute copies to the public, perform
22  * publicly and display publicly, and to permit others to do so.
23  *
24  * This code is distributed under a BSD style license, see the LICENSE
25  * file for complete information.
26  *
27  * Based on timers.c by Jef Poskanzer. Used with permission.
28  */
29 
30 #include <sys/types.h>
31 #include <stdlib.h>
32 
33 #include "timer.h"
34 #include "iperf_time.h"
35 
36 static Timer* timers = NULL;
37 static Timer* free_timers = NULL;
38 
39 TimerClientData JunkClientData;
40 
41 
42 
43 /* This is an efficiency tweak.  All the routines that need to know the
44 ** current time get passed a pointer to a struct iperf_time.  If it's non-NULL
45 ** it gets used, otherwise we do our own iperf_time_now() to fill it in.
46 ** This lets the caller avoid extraneous iperf_time_now()s when efficiency
47 ** is needed, and not bother with the extra code when efficiency doesn't
48 ** matter too much.
49 */
50 static void
getnow(struct iperf_time * nowP,struct iperf_time * nowP2)51 getnow( struct iperf_time* nowP, struct iperf_time* nowP2 )
52 {
53     if ( nowP != NULL )
54 	*nowP2 = *nowP;
55     else
56 	iperf_time_now(nowP2);
57 }
58 
59 
60 static void
list_add(Timer * t)61 list_add( Timer* t )
62 {
63     Timer* t2;
64     Timer* t2prev;
65 
66     if ( timers == NULL ) {
67 	/* The list is empty. */
68 	timers = t;
69 	t->prev = t->next = NULL;
70     } else {
71 	if (iperf_time_compare(&t->time, &timers->time) < 0) {
72 	    /* The new timer goes at the head of the list. */
73 	    t->prev = NULL;
74 	    t->next = timers;
75 	    timers->prev = t;
76 	    timers = t;
77 	} else {
78 	    /* Walk the list to find the insertion point. */
79 	    for ( t2prev = timers, t2 = timers->next; t2 != NULL;
80 		  t2prev = t2, t2 = t2->next ) {
81 		if (iperf_time_compare(&t->time, &t2->time) < 0) {
82 		    /* Found it. */
83 		    t2prev->next = t;
84 		    t->prev = t2prev;
85 		    t->next = t2;
86 		    t2->prev = t;
87 		    return;
88 		}
89 	    }
90 	    /* Oops, got to the end of the list.  Add to tail. */
91 	    t2prev->next = t;
92 	    t->prev = t2prev;
93 	    t->next = NULL;
94 	}
95     }
96 }
97 
98 
99 static void
list_remove(Timer * t)100 list_remove( Timer* t )
101 {
102     if ( t->prev == NULL )
103 	timers = t->next;
104     else
105 	t->prev->next = t->next;
106     if ( t->next != NULL )
107 	t->next->prev = t->prev;
108 }
109 
110 
111 static void
list_resort(Timer * t)112 list_resort( Timer* t )
113 {
114     /* Remove the timer from the list. */
115     list_remove( t );
116     /* And add it back in, sorted correctly. */
117     list_add( t );
118 }
119 
120 
121 Timer*
tmr_create(struct iperf_time * nowP,TimerProc * timer_proc,TimerClientData client_data,int64_t usecs,int periodic)122 tmr_create(
123     struct iperf_time* nowP, TimerProc* timer_proc, TimerClientData client_data,
124     int64_t usecs, int periodic )
125 {
126     struct iperf_time now;
127     Timer* t;
128 
129     getnow( nowP, &now );
130 
131     if ( free_timers != NULL ) {
132 	t = free_timers;
133 	free_timers = t->next;
134     } else {
135 	t = (Timer*) malloc( sizeof(Timer) );
136 	if ( t == NULL )
137 	    return NULL;
138     }
139 
140     t->timer_proc = timer_proc;
141     t->client_data = client_data;
142     t->usecs = usecs;
143     t->periodic = periodic;
144     t->time = now;
145     iperf_time_add_usecs(&t->time, usecs);
146     /* Add the new timer to the active list. */
147     list_add( t );
148 
149     return t;
150 }
151 
152 
153 struct timeval*
tmr_timeout(struct iperf_time * nowP)154 tmr_timeout( struct iperf_time* nowP )
155 {
156     struct iperf_time now, diff;
157     int64_t usecs;
158     int past;
159     static struct timeval timeout;
160 
161     getnow( nowP, &now );
162     /* Since the list is sorted, we only need to look at the first timer. */
163     if ( timers == NULL )
164 	return NULL;
165     past = iperf_time_diff(&timers->time, &now, &diff);
166     if (past)
167         usecs = 0;
168     else
169         usecs = iperf_time_in_usecs(&diff);
170     timeout.tv_sec = usecs / 1000000LL;
171     timeout.tv_usec = usecs % 1000000LL;
172     return &timeout;
173 }
174 
175 
176 void
tmr_run(struct iperf_time * nowP)177 tmr_run( struct iperf_time* nowP )
178 {
179     struct iperf_time now;
180     Timer* t;
181     Timer* next;
182 
183     getnow( nowP, &now );
184     for ( t = timers; t != NULL; t = next ) {
185 	next = t->next;
186 	/* Since the list is sorted, as soon as we find a timer
187 	** that isn't ready yet, we are done.
188 	*/
189 	if (iperf_time_compare(&t->time, &now) > 0)
190 	    break;
191 	(t->timer_proc)( t->client_data, &now );
192 	if ( t->periodic ) {
193 	    /* Reschedule. */
194 	    iperf_time_add_usecs(&t->time, t->usecs);
195 	    list_resort( t );
196 	} else
197 	    tmr_cancel( t );
198     }
199 }
200 
201 
202 void
tmr_reset(struct iperf_time * nowP,Timer * t)203 tmr_reset( struct iperf_time* nowP, Timer* t )
204 {
205     struct iperf_time now;
206 
207     getnow( nowP, &now );
208     t->time = now;
209     iperf_time_add_usecs( &t->time, t->usecs );
210     list_resort( t );
211 }
212 
213 
214 void
tmr_cancel(Timer * t)215 tmr_cancel( Timer* t )
216 {
217     /* Remove it from the active list. */
218     list_remove( t );
219     /* And put it on the free list. */
220     t->next = free_timers;
221     free_timers = t;
222     t->prev = NULL;
223 }
224 
225 
226 void
tmr_cleanup(void)227 tmr_cleanup( void )
228 {
229     Timer* t;
230 
231     while ( free_timers != NULL ) {
232 	t = free_timers;
233 	free_timers = t->next;
234 	free( (void*) t );
235     }
236 }
237 
238 
239 void
tmr_destroy(void)240 tmr_destroy( void )
241 {
242     while ( timers != NULL )
243 	tmr_cancel( timers );
244     tmr_cleanup();
245 }
246