1/*
2 * configurable RSSI LED control daemon for OpenWrt
3 *  (c) 2012 Allnet GmbH, Daniel Golle <dgolle@allnet.de>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 *
19 * The author may be reached as dgolle@allnet.de, or
20 * ALLNET GmbH
21 * Maistr. 2
22 * D-82110 Germering
23 * Germany
24 *
25 */
26
27#include <stdio.h>
28#include <stdlib.h>
29#include <sys/stat.h>
30#include <fcntl.h>
31#include <signal.h>
32#include <unistd.h>
33#include <syslog.h>
34
35#include "iwinfo.h"
36
37#define RUN_DIR			"/var/run"
38#define LEDS_BASEPATH		"/sys/class/leds/"
39#define BACKEND_RETRY_DELAY	500000
40
41char *ifname;
42int qual_max;
43
44struct led {
45	char *sysfspath;
46	FILE *controlfd;
47	unsigned char state;
48};
49
50typedef struct rule rule_t;
51struct rule {
52	struct led *led;
53	int minq;
54	int maxq;
55	int boffset;
56	int bfactor;
57	rule_t *next;
58};
59
60void log_rules(rule_t *rules)
61{
62	rule_t *rule = rules;
63	while (rule)
64	{
65		syslog(LOG_INFO, " %s r: %d..%d, o: %d, f: %d\n",
66			rule->led->sysfspath,
67			rule->minq, rule->maxq,
68			rule->boffset, rule->bfactor);
69		rule = rule->next;
70	}
71}
72
73int set_led(struct led *led, unsigned char value)
74{
75	char buf[8];
76
77	if ( ! led )
78		return -1;
79
80	if ( ! led->controlfd )
81		return -1;
82
83	if ( led->state == value )
84		return 0;
85
86	snprintf(buf, 8, "%d", value);
87
88	rewind(led->controlfd);
89
90	if ( ! fwrite(buf, sizeof(char), strlen(buf), led->controlfd) )
91		return -2;
92
93	fflush(led->controlfd);
94	led->state=value;
95
96	return 0;
97}
98
99int init_led(struct led **led, char *ledname)
100{
101	struct led *newled;
102	struct stat statbuffer;
103	int status;
104	char *bp;
105	FILE *bfp;
106
107	bp = calloc(sizeof(char), strlen(ledname) + strlen(LEDS_BASEPATH) + 12);
108	if ( ! bp )
109		goto return_error;
110
111	sprintf(bp, "%s%s/brightness", LEDS_BASEPATH, ledname);
112
113	status = stat(bp, &statbuffer);
114	if ( status )
115		goto cleanup_fname;
116
117	bfp = fopen( bp, "w" );
118	if ( !bfp )
119		goto cleanup_fname;
120
121	if ( ferror(bfp) )
122		goto cleanup_fp;
123
124	/* sysfs path exists and, allocate LED struct */
125	newled = calloc(sizeof(struct led),1);
126	if ( !newled )
127		goto cleanup_fp;
128
129	newled->sysfspath = bp;
130	newled->controlfd = bfp;
131
132	*led = newled;
133
134	if ( set_led(newled, 255) )
135		goto cleanup_fp;
136
137	if ( set_led(newled, 0) )
138		goto cleanup_fp;
139
140	return 0;
141
142cleanup_fp:
143	fclose(bfp);
144cleanup_fname:
145	free(bp);
146return_error:
147	syslog(LOG_CRIT, "can't open LED %s\n", ledname);
148	*led = NULL;
149	return -1;
150}
151
152void close_led(struct led **led)
153{
154	fclose((*led)->controlfd);
155	free((*led)->sysfspath);
156	free((*led));
157	(*led)=NULL;
158}
159
160
161int quality(const struct iwinfo_ops *iw, const char *ifname)
162{
163	int qual;
164
165	if ( ! iw ) return -1;
166
167	if (qual_max < 1)
168		if (iw->quality_max(ifname, &qual_max))
169			return -1;
170
171	if (iw->quality(ifname, &qual))
172		return -1;
173
174	return ( qual * 100 ) / qual_max ;
175}
176
177int open_backend(const struct iwinfo_ops **iw, const char *ifname)
178{
179	*iw = iwinfo_backend(ifname);
180
181	if (!(*iw))
182		return 1;
183
184	return 0;
185}
186
187void update_leds(rule_t *rules, int q)
188{
189	rule_t *rule = rules;
190	while (rule)
191	{
192		int b;
193		/* offset and factore correction according to rule */
194		b = ( q + rule->boffset ) * rule->bfactor;
195		if ( b < 0 )
196			b=0;
197		if ( b > 255 )
198			b=255;
199
200		if ( q >= rule->minq && q <= rule->maxq )
201			set_led(rule->led, (unsigned char)b);
202		else
203			set_led(rule->led, 0);
204
205		rule = rule->next;
206	}
207}
208
209int main(int argc, char **argv)
210{
211	int i,q,q0,r,s;
212	const struct iwinfo_ops *iw = NULL;
213	rule_t *headrule = NULL, *currentrule = NULL;
214
215	if (argc < 9 || ( (argc-4) % 5 != 0 ) )
216	{
217		printf("syntax: %s (ifname) (refresh) (threshold) (rule) [rule] ...\n", argv[0]);
218		printf("  rule: (sysfs-name) (minq) (maxq) (offset) (factore)\n");
219		return 1;
220	}
221
222	ifname = argv[1];
223
224	/* refresh interval */
225	if ( sscanf(argv[2], "%d", &r) != 1 )
226		return 1;
227
228	/* sustain threshold */
229	if ( sscanf(argv[3], "%d", &s) != 1 )
230		return 1;
231
232	openlog("rssileds", LOG_PID, LOG_DAEMON);
233	syslog(LOG_INFO, "monitoring %s, refresh rate %d, threshold %d\n", ifname, r, s);
234
235	currentrule = headrule;
236	for (i=4; i<argc; i=i+5) {
237		if (! currentrule)
238		{
239			/* first element in the list */
240			currentrule = calloc(sizeof(rule_t),1);
241			headrule = currentrule;
242		}
243		else
244		{
245			/* follow-up element */
246			currentrule->next = calloc(sizeof(rule_t),1);
247			currentrule = currentrule->next;
248		}
249
250		if ( init_led(&(currentrule->led), argv[i]) )
251			return 1;
252
253		if ( sscanf(argv[i+1], "%d", &(currentrule->minq)) != 1 )
254			return 1;
255
256		if ( sscanf(argv[i+2], "%d", &(currentrule->maxq)) != 1 )
257			return 1;
258
259		if ( sscanf(argv[i+3], "%d", &(currentrule->boffset)) != 1 )
260			return 1;
261
262		if ( sscanf(argv[i+4], "%d", &(currentrule->bfactor)) != 1 )
263			return 1;
264	}
265	log_rules(headrule);
266
267	q0 = -1;
268	do {
269		q = quality(iw, ifname);
270		if ( q < q0 - s || q > q0 + s ) {
271			update_leds(headrule, q);
272			q0=q;
273		};
274		// re-open backend...
275		if ( q == -1 && q0 == -1 ) {
276			if (iw) {
277				iwinfo_finish();
278				iw=NULL;
279				usleep(BACKEND_RETRY_DELAY);
280			}
281			while (open_backend(&iw, ifname))
282				usleep(BACKEND_RETRY_DELAY);
283		}
284		usleep(r);
285	} while(1);
286
287	iwinfo_finish();
288
289	return 0;
290}
291