1 /*
2  * P2P - generic helper functions
3  * Copyright (c) 2009, Atheros Communications
4  *
5  * This software may be distributed under the terms of the BSD license.
6  * See README for more details.
7  */
8 
9 #include "includes.h"
10 
11 #include "common.h"
12 #include "p2p_i.h"
13 
14 
15 /**
16  * p2p_random - Generate random string for SSID and passphrase
17  * @buf: Buffer for returning the result
18  * @len: Number of octets to write to the buffer
19  * Returns: 0 on success, -1 on failure
20  *
21  * This function generates a random string using the following character set:
22  * 'A'-'Z', 'a'-'z', '0'-'9'.
23  */
24 int p2p_random(char *buf, size_t len)
25 {
26 	u8 val;
27 	size_t i;
28 	u8 letters = 'Z' - 'A' + 1;
29 	u8 numbers = 10;
30 
31 	if (os_get_random((unsigned char *) buf, len))
32 		return -1;
33 	/* Character set: 'A'-'Z', 'a'-'z', '0'-'9' */
34 	for (i = 0; i < len; i++) {
35 		val = buf[i];
36 		val %= 2 * letters + numbers;
37 		if (val < letters)
38 			buf[i] = 'A' + val;
39 		else if (val < 2 * letters)
40 			buf[i] = 'a' + (val - letters);
41 		else
42 			buf[i] = '0' + (val - 2 * letters);
43 	}
44 
45 	return 0;
46 }
47 
48 
49 /**
50  * p2p_channel_to_freq - Convert channel info to frequency
51  * @op_class: Operating class
52  * @channel: Channel number
53  * Returns: Frequency in MHz or -1 if the specified channel is unknown
54  */
55 int p2p_channel_to_freq(int op_class, int channel)
56 {
57 	/* Table E-4 in IEEE Std 802.11-2012 - Global operating classes */
58 	/* TODO: more operating classes */
59 	switch (op_class) {
60 	case 81:
61 		/* channels 1..13 */
62 		if (channel < 1 || channel > 13)
63 			return -1;
64 		return 2407 + 5 * channel;
65 	case 82:
66 		/* channel 14 */
67 		if (channel != 14)
68 			return -1;
69 		return 2414 + 5 * channel;
70 	case 83: /* channels 1..9; 40 MHz */
71 	case 84: /* channels 5..13; 40 MHz */
72 		if (channel < 1 || channel > 13)
73 			return -1;
74 		return 2407 + 5 * channel;
75 	case 115: /* channels 36,40,44,48; indoor only */
76 	case 118: /* channels 52,56,60,64; dfs */
77 		if (channel < 36 || channel > 64)
78 			return -1;
79 		return 5000 + 5 * channel;
80 	case 124: /* channels 149,153,157,161 */
81 	case 125: /* channels 149,153,157,161,165,169 */
82 		if (channel < 149 || channel > 161)
83 			return -1;
84 		return 5000 + 5 * channel;
85 	case 116: /* channels 36,44; 40 MHz; indoor only */
86 	case 117: /* channels 40,48; 40 MHz; indoor only */
87 	case 119: /* channels 52,60; 40 MHz; dfs */
88 	case 120: /* channels 56,64; 40 MHz; dfs */
89 		if (channel < 36 || channel > 64)
90 			return -1;
91 		return 5000 + 5 * channel;
92 	case 126: /* channels 149,157; 40 MHz */
93 	case 127: /* channels 153,161; 40 MHz */
94 		if (channel < 149 || channel > 161)
95 			return -1;
96 		return 5000 + 5 * channel;
97 	case 128: /* center freqs 42, 58, 106, 122, 138, 155; 80 MHz */
98 		if (channel < 36 || channel > 161)
99 			return -1;
100 		return 5000 + 5 * channel;
101 	}
102 	return -1;
103 }
104 
105 
106 /**
107  * p2p_freq_to_channel - Convert frequency into channel info
108  * @op_class: Buffer for returning operating class
109  * @channel: Buffer for returning channel number
110  * Returns: 0 on success, -1 if the specified frequency is unknown
111  */
112 int p2p_freq_to_channel(unsigned int freq, u8 *op_class, u8 *channel)
113 {
114 	/* TODO: more operating classes */
115 	if (freq >= 2412 && freq <= 2472) {
116 		if ((freq - 2407) % 5)
117 			return -1;
118 
119 		*op_class = 81; /* 2.407 GHz, channels 1..13 */
120 		*channel = (freq - 2407) / 5;
121 		return 0;
122 	}
123 
124 	if (freq == 2484) {
125 		*op_class = 82; /* channel 14 */
126 		*channel = 14;
127 		return 0;
128 	}
129 
130 	if (freq >= 5180 && freq <= 5240) {
131 		if ((freq - 5000) % 5)
132 			return -1;
133 
134 		*op_class = 115; /* 5 GHz, channels 36..48 */
135 		*channel = (freq - 5000) / 5;
136 		return 0;
137 	}
138 
139 	if (freq >= 5745 && freq <= 5805) {
140 		if ((freq - 5000) % 5)
141 			return -1;
142 
143 		*op_class = 124; /* 5 GHz, channels 149..161 */
144 		*channel = (freq - 5000) / 5;
145 		return 0;
146 	}
147 
148 	return -1;
149 }
150 
151 
152 static void p2p_reg_class_intersect(const struct p2p_reg_class *a,
153 				    const struct p2p_reg_class *b,
154 				    struct p2p_reg_class *res)
155 {
156 	size_t i, j;
157 
158 	res->reg_class = a->reg_class;
159 
160 	for (i = 0; i < a->channels; i++) {
161 		for (j = 0; j < b->channels; j++) {
162 			if (a->channel[i] != b->channel[j])
163 				continue;
164 			res->channel[res->channels] = a->channel[i];
165 			res->channels++;
166 			if (res->channels == P2P_MAX_REG_CLASS_CHANNELS)
167 				return;
168 		}
169 	}
170 }
171 
172 
173 /**
174  * p2p_channels_intersect - Intersection of supported channel lists
175  * @a: First set of supported channels
176  * @b: Second set of supported channels
177  * @res: Data structure for returning the intersection of support channels
178  *
179  * This function can be used to find a common set of supported channels. Both
180  * input channels sets are assumed to use the same country code. If different
181  * country codes are used, the regulatory class numbers may not be matched
182  * correctly and results are undefined.
183  */
184 void p2p_channels_intersect(const struct p2p_channels *a,
185 			    const struct p2p_channels *b,
186 			    struct p2p_channels *res)
187 {
188 	size_t i, j;
189 
190 	os_memset(res, 0, sizeof(*res));
191 
192 	for (i = 0; i < a->reg_classes; i++) {
193 		const struct p2p_reg_class *a_reg = &a->reg_class[i];
194 		for (j = 0; j < b->reg_classes; j++) {
195 			const struct p2p_reg_class *b_reg = &b->reg_class[j];
196 			if (a_reg->reg_class != b_reg->reg_class)
197 				continue;
198 			p2p_reg_class_intersect(
199 				a_reg, b_reg,
200 				&res->reg_class[res->reg_classes]);
201 			if (res->reg_class[res->reg_classes].channels) {
202 				res->reg_classes++;
203 				if (res->reg_classes == P2P_MAX_REG_CLASSES)
204 					return;
205 			}
206 		}
207 	}
208 }
209 
210 
211 static void p2p_op_class_union(struct p2p_reg_class *cl,
212 			       const struct p2p_reg_class *b_cl)
213 {
214 	size_t i, j;
215 
216 	for (i = 0; i < b_cl->channels; i++) {
217 		for (j = 0; j < cl->channels; j++) {
218 			if (b_cl->channel[i] == cl->channel[j])
219 				break;
220 		}
221 		if (j == cl->channels) {
222 			if (cl->channels == P2P_MAX_REG_CLASS_CHANNELS)
223 				return;
224 			cl->channel[cl->channels++] = b_cl->channel[i];
225 		}
226 	}
227 }
228 
229 
230 /**
231  * p2p_channels_union - Union of channel lists
232  * @a: First set of channels
233  * @b: Second set of channels
234  * @res: Data structure for returning the union of channels
235  */
236 void p2p_channels_union(const struct p2p_channels *a,
237 			const struct p2p_channels *b,
238 			struct p2p_channels *res)
239 {
240 	size_t i, j;
241 
242 	if (a != res)
243 		os_memcpy(res, a, sizeof(*res));
244 
245 	for (i = 0; i < res->reg_classes; i++) {
246 		struct p2p_reg_class *cl = &res->reg_class[i];
247 		for (j = 0; j < b->reg_classes; j++) {
248 			const struct p2p_reg_class *b_cl = &b->reg_class[j];
249 			if (cl->reg_class != b_cl->reg_class)
250 				continue;
251 			p2p_op_class_union(cl, b_cl);
252 		}
253 	}
254 
255 	for (j = 0; j < b->reg_classes; j++) {
256 		const struct p2p_reg_class *b_cl = &b->reg_class[j];
257 
258 		for (i = 0; i < res->reg_classes; i++) {
259 			struct p2p_reg_class *cl = &res->reg_class[i];
260 			if (cl->reg_class == b_cl->reg_class)
261 				break;
262 		}
263 
264 		if (i == res->reg_classes) {
265 			if (res->reg_classes == P2P_MAX_REG_CLASSES)
266 				return;
267 			os_memcpy(&res->reg_class[res->reg_classes++],
268 				  b_cl, sizeof(struct p2p_reg_class));
269 		}
270 	}
271 }
272 
273 
274 void p2p_channels_remove_freqs(struct p2p_channels *chan,
275 			       const struct wpa_freq_range_list *list)
276 {
277 	size_t o, c;
278 
279 	if (list == NULL)
280 		return;
281 
282 	o = 0;
283 	while (o < chan->reg_classes) {
284 		struct p2p_reg_class *op = &chan->reg_class[o];
285 
286 		c = 0;
287 		while (c < op->channels) {
288 			int freq = p2p_channel_to_freq(op->reg_class,
289 						       op->channel[c]);
290 			if (freq > 0 && freq_range_list_includes(list, freq)) {
291 				op->channels--;
292 				os_memmove(&op->channel[c],
293 					   &op->channel[c + 1],
294 					   op->channels - c);
295 			} else
296 				c++;
297 		}
298 
299 		if (op->channels == 0) {
300 			chan->reg_classes--;
301 			os_memmove(&chan->reg_class[o], &chan->reg_class[o + 1],
302 				   (chan->reg_classes - o) *
303 				   sizeof(struct p2p_reg_class));
304 		} else
305 			o++;
306 	}
307 }
308 
309 
310 /**
311  * p2p_channels_includes - Check whether a channel is included in the list
312  * @channels: List of supported channels
313  * @reg_class: Regulatory class of the channel to search
314  * @channel: Channel number of the channel to search
315  * Returns: 1 if channel was found or 0 if not
316  */
317 int p2p_channels_includes(const struct p2p_channels *channels, u8 reg_class,
318 			  u8 channel)
319 {
320 	size_t i, j;
321 	for (i = 0; i < channels->reg_classes; i++) {
322 		const struct p2p_reg_class *reg = &channels->reg_class[i];
323 		if (reg->reg_class != reg_class)
324 			continue;
325 		for (j = 0; j < reg->channels; j++) {
326 			if (reg->channel[j] == channel)
327 				return 1;
328 		}
329 	}
330 	return 0;
331 }
332 
333 
334 int p2p_channels_includes_freq(const struct p2p_channels *channels,
335 			       unsigned int freq)
336 {
337 	size_t i, j;
338 	for (i = 0; i < channels->reg_classes; i++) {
339 		const struct p2p_reg_class *reg = &channels->reg_class[i];
340 		for (j = 0; j < reg->channels; j++) {
341 			if (p2p_channel_to_freq(reg->reg_class,
342 						reg->channel[j]) == (int) freq)
343 				return 1;
344 		}
345 	}
346 	return 0;
347 }
348 
349 
350 int p2p_supported_freq(struct p2p_data *p2p, unsigned int freq)
351 {
352 	u8 op_reg_class, op_channel;
353 	if (p2p_freq_to_channel(freq, &op_reg_class, &op_channel) < 0)
354 		return 0;
355 	return p2p_channels_includes(&p2p->cfg->channels, op_reg_class,
356 				     op_channel);
357 }
358 
359 
360 int p2p_supported_freq_go(struct p2p_data *p2p, unsigned int freq)
361 {
362 	u8 op_reg_class, op_channel;
363 	if (p2p_freq_to_channel(freq, &op_reg_class, &op_channel) < 0)
364 		return 0;
365 	return p2p_channels_includes(&p2p->cfg->channels, op_reg_class,
366 				     op_channel) &&
367 		!freq_range_list_includes(&p2p->no_go_freq, freq);
368 }
369 
370 
371 int p2p_supported_freq_cli(struct p2p_data *p2p, unsigned int freq)
372 {
373 	u8 op_reg_class, op_channel;
374 	if (p2p_freq_to_channel(freq, &op_reg_class, &op_channel) < 0)
375 		return 0;
376 	return p2p_channels_includes(&p2p->cfg->channels, op_reg_class,
377 				     op_channel) ||
378 		p2p_channels_includes(&p2p->cfg->cli_channels, op_reg_class,
379 				      op_channel);
380 }
381 
382 
383 unsigned int p2p_get_pref_freq(struct p2p_data *p2p,
384 			       const struct p2p_channels *channels)
385 {
386 	unsigned int i;
387 	int freq = 0;
388 
389 	if (channels == NULL) {
390 		if (p2p->cfg->num_pref_chan) {
391 			freq = p2p_channel_to_freq(
392 				p2p->cfg->pref_chan[0].op_class,
393 				p2p->cfg->pref_chan[0].chan);
394 			if (freq < 0)
395 				freq = 0;
396 		}
397 		return freq;
398 	}
399 
400 	for (i = 0; p2p->cfg->pref_chan && i < p2p->cfg->num_pref_chan; i++) {
401 		freq = p2p_channel_to_freq(p2p->cfg->pref_chan[i].op_class,
402 					   p2p->cfg->pref_chan[i].chan);
403 		if (p2p_channels_includes_freq(channels, freq))
404 			return freq;
405 	}
406 
407 	return 0;
408 }
409 
410 
411 void p2p_channels_dump(struct p2p_data *p2p, const char *title,
412 		       const struct p2p_channels *chan)
413 {
414 	char buf[500], *pos, *end;
415 	size_t i, j;
416 	int ret;
417 
418 	pos = buf;
419 	end = pos + sizeof(buf);
420 
421 	for (i = 0; i < chan->reg_classes; i++) {
422 		const struct p2p_reg_class *c;
423 		c = &chan->reg_class[i];
424 		ret = os_snprintf(pos, end - pos, " %u:", c->reg_class);
425 		if (ret < 0 || ret >= end - pos)
426 			break;
427 		pos += ret;
428 
429 		for (j = 0; j < c->channels; j++) {
430 			ret = os_snprintf(pos, end - pos, "%s%u",
431 					  j == 0 ? "" : ",",
432 					  c->channel[j]);
433 			if (ret < 0 || ret >= end - pos)
434 				break;
435 			pos += ret;
436 		}
437 	}
438 	*pos = '\0';
439 
440 	p2p_dbg(p2p, "%s:%s", title, buf);
441 }
442 
443 
444 int p2p_channel_select(struct p2p_channels *chans, const int *classes,
445 		       u8 *op_class, u8 *op_channel)
446 {
447 	unsigned int i, j, r;
448 
449 	for (j = 0; classes[j]; j++) {
450 		for (i = 0; i < chans->reg_classes; i++) {
451 			struct p2p_reg_class *c = &chans->reg_class[i];
452 
453 			if (c->channels == 0)
454 				continue;
455 
456 			if (c->reg_class == classes[j]) {
457 				/*
458 				 * Pick one of the available channels in the
459 				 * operating class at random.
460 				 */
461 				os_get_random((u8 *) &r, sizeof(r));
462 				r %= c->channels;
463 				*op_class = c->reg_class;
464 				*op_channel = c->channel[r];
465 				return 0;
466 			}
467 		}
468 	}
469 
470 	return -1;
471 }
472