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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 "common/defs.h"
13 #include "common/ieee802_11_common.h"
14 #include "p2p_i.h"
15 
16 
17 /**
18  * p2p_random - Generate random string for SSID and passphrase
19  * @buf: Buffer for returning the result
20  * @len: Number of octets to write to the buffer
21  * Returns: 0 on success, -1 on failure
22  *
23  * This function generates a random string using the following character set:
24  * 'A'-'Z', 'a'-'z', '0'-'9'.
25  */
p2p_random(char * buf,size_t len)26 int p2p_random(char *buf, size_t len)
27 {
28 	u8 val;
29 	size_t i;
30 	u8 letters = 'Z' - 'A' + 1;
31 	u8 numbers = 10;
32 
33 	if (os_get_random((unsigned char *) buf, len))
34 		return -1;
35 	/* Character set: 'A'-'Z', 'a'-'z', '0'-'9' */
36 	for (i = 0; i < len; i++) {
37 		val = buf[i];
38 		val %= 2 * letters + numbers;
39 		if (val < letters)
40 			buf[i] = 'A' + val;
41 		else if (val < 2 * letters)
42 			buf[i] = 'a' + (val - letters);
43 		else
44 			buf[i] = '0' + (val - 2 * letters);
45 	}
46 
47 	return 0;
48 }
49 
50 
51 /**
52  * p2p_channel_to_freq - Convert channel info to frequency
53  * @op_class: Operating class
54  * @channel: Channel number
55  * Returns: Frequency in MHz or -1 if the specified channel is unknown
56  */
p2p_channel_to_freq(int op_class,int channel)57 int p2p_channel_to_freq(int op_class, int channel)
58 {
59 	return ieee80211_chan_to_freq(NULL, op_class, channel);
60 }
61 
62 
63 /**
64  * p2p_freq_to_channel - Convert frequency into channel info
65  * @op_class: Buffer for returning operating class
66  * @channel: Buffer for returning channel number
67  * Returns: 0 on success, -1 if the specified frequency is unknown
68  */
p2p_freq_to_channel(unsigned int freq,u8 * op_class,u8 * channel)69 int p2p_freq_to_channel(unsigned int freq, u8 *op_class, u8 *channel)
70 {
71 	if (ieee80211_freq_to_channel_ext(freq, 0, 0, op_class, channel) ==
72 	    NUM_HOSTAPD_MODES)
73 		return -1;
74 
75 	return 0;
76 }
77 
78 
p2p_reg_class_intersect(const struct p2p_reg_class * a,const struct p2p_reg_class * b,struct p2p_reg_class * res)79 static void p2p_reg_class_intersect(const struct p2p_reg_class *a,
80 				    const struct p2p_reg_class *b,
81 				    struct p2p_reg_class *res)
82 {
83 	size_t i, j;
84 
85 	res->reg_class = a->reg_class;
86 
87 	for (i = 0; i < a->channels; i++) {
88 		for (j = 0; j < b->channels; j++) {
89 			if (a->channel[i] != b->channel[j])
90 				continue;
91 			res->channel[res->channels] = a->channel[i];
92 			res->channels++;
93 			if (res->channels == P2P_MAX_REG_CLASS_CHANNELS)
94 				return;
95 		}
96 	}
97 }
98 
99 
100 /**
101  * p2p_channels_intersect - Intersection of supported channel lists
102  * @a: First set of supported channels
103  * @b: Second set of supported channels
104  * @res: Data structure for returning the intersection of support channels
105  *
106  * This function can be used to find a common set of supported channels. Both
107  * input channels sets are assumed to use the same country code. If different
108  * country codes are used, the regulatory class numbers may not be matched
109  * correctly and results are undefined.
110  */
p2p_channels_intersect(const struct p2p_channels * a,const struct p2p_channels * b,struct p2p_channels * res)111 void p2p_channels_intersect(const struct p2p_channels *a,
112 			    const struct p2p_channels *b,
113 			    struct p2p_channels *res)
114 {
115 	size_t i, j;
116 
117 	os_memset(res, 0, sizeof(*res));
118 
119 	for (i = 0; i < a->reg_classes; i++) {
120 		const struct p2p_reg_class *a_reg = &a->reg_class[i];
121 		for (j = 0; j < b->reg_classes; j++) {
122 			const struct p2p_reg_class *b_reg = &b->reg_class[j];
123 			if (a_reg->reg_class != b_reg->reg_class)
124 				continue;
125 			p2p_reg_class_intersect(
126 				a_reg, b_reg,
127 				&res->reg_class[res->reg_classes]);
128 			if (res->reg_class[res->reg_classes].channels) {
129 				res->reg_classes++;
130 				if (res->reg_classes == P2P_MAX_REG_CLASSES)
131 					return;
132 			}
133 		}
134 	}
135 }
136 
137 
p2p_op_class_union(struct p2p_reg_class * cl,const struct p2p_reg_class * b_cl)138 static void p2p_op_class_union(struct p2p_reg_class *cl,
139 			       const struct p2p_reg_class *b_cl)
140 {
141 	size_t i, j;
142 
143 	for (i = 0; i < b_cl->channels; i++) {
144 		for (j = 0; j < cl->channels; j++) {
145 			if (b_cl->channel[i] == cl->channel[j])
146 				break;
147 		}
148 		if (j == cl->channels) {
149 			if (cl->channels == P2P_MAX_REG_CLASS_CHANNELS)
150 				return;
151 			cl->channel[cl->channels++] = b_cl->channel[i];
152 		}
153 	}
154 }
155 
156 
157 /**
158  * p2p_channels_union_inplace - Inplace union of channel lists
159  * @res: Input data and place for returning union of the channel sets
160  * @b: Second set of channels
161  */
p2p_channels_union_inplace(struct p2p_channels * res,const struct p2p_channels * b)162 void p2p_channels_union_inplace(struct p2p_channels *res,
163 				const struct p2p_channels *b)
164 {
165 	size_t i, j;
166 
167 	for (i = 0; i < res->reg_classes; i++) {
168 		struct p2p_reg_class *cl = &res->reg_class[i];
169 		for (j = 0; j < b->reg_classes; j++) {
170 			const struct p2p_reg_class *b_cl = &b->reg_class[j];
171 			if (cl->reg_class != b_cl->reg_class)
172 				continue;
173 			p2p_op_class_union(cl, b_cl);
174 		}
175 	}
176 
177 	for (j = 0; j < b->reg_classes; j++) {
178 		const struct p2p_reg_class *b_cl = &b->reg_class[j];
179 
180 		for (i = 0; i < res->reg_classes; i++) {
181 			struct p2p_reg_class *cl = &res->reg_class[i];
182 			if (cl->reg_class == b_cl->reg_class)
183 				break;
184 		}
185 
186 		if (i == res->reg_classes) {
187 			if (res->reg_classes == P2P_MAX_REG_CLASSES)
188 				return;
189 			os_memcpy(&res->reg_class[res->reg_classes++],
190 				  b_cl, sizeof(struct p2p_reg_class));
191 		}
192 	}
193 }
194 
195 
196 /**
197  * p2p_channels_union - Union of channel lists
198  * @a: First set of channels
199  * @b: Second set of channels
200  * @res: Data structure for returning the union of channels
201  */
p2p_channels_union(const struct p2p_channels * a,const struct p2p_channels * b,struct p2p_channels * res)202 void p2p_channels_union(const struct p2p_channels *a,
203 			const struct p2p_channels *b,
204 			struct p2p_channels *res)
205 {
206 	os_memcpy(res, a, sizeof(*res));
207 	p2p_channels_union_inplace(res, b);
208 }
209 
210 
p2p_channels_remove_freqs(struct p2p_channels * chan,const struct wpa_freq_range_list * list)211 void p2p_channels_remove_freqs(struct p2p_channels *chan,
212 			       const struct wpa_freq_range_list *list)
213 {
214 	size_t o, c;
215 
216 	if (list == NULL)
217 		return;
218 
219 	o = 0;
220 	while (o < chan->reg_classes) {
221 		struct p2p_reg_class *op = &chan->reg_class[o];
222 
223 		c = 0;
224 		while (c < op->channels) {
225 			int freq = p2p_channel_to_freq(op->reg_class,
226 						       op->channel[c]);
227 			if (freq > 0 && freq_range_list_includes(list, freq)) {
228 				op->channels--;
229 				os_memmove(&op->channel[c],
230 					   &op->channel[c + 1],
231 					   op->channels - c);
232 			} else
233 				c++;
234 		}
235 
236 		if (op->channels == 0) {
237 			chan->reg_classes--;
238 			os_memmove(&chan->reg_class[o], &chan->reg_class[o + 1],
239 				   (chan->reg_classes - o) *
240 				   sizeof(struct p2p_reg_class));
241 		} else
242 			o++;
243 	}
244 }
245 
246 
247 /**
248  * p2p_channels_includes - Check whether a channel is included in the list
249  * @channels: List of supported channels
250  * @reg_class: Regulatory class of the channel to search
251  * @channel: Channel number of the channel to search
252  * Returns: 1 if channel was found or 0 if not
253  */
p2p_channels_includes(const struct p2p_channels * channels,u8 reg_class,u8 channel)254 int p2p_channels_includes(const struct p2p_channels *channels, u8 reg_class,
255 			  u8 channel)
256 {
257 	size_t i, j;
258 	for (i = 0; i < channels->reg_classes; i++) {
259 		const struct p2p_reg_class *reg = &channels->reg_class[i];
260 		if (reg->reg_class != reg_class)
261 			continue;
262 		for (j = 0; j < reg->channels; j++) {
263 			if (reg->channel[j] == channel)
264 				return 1;
265 		}
266 	}
267 	return 0;
268 }
269 
270 
p2p_channels_includes_freq(const struct p2p_channels * channels,unsigned int freq)271 int p2p_channels_includes_freq(const struct p2p_channels *channels,
272 			       unsigned int freq)
273 {
274 	size_t i, j;
275 	for (i = 0; i < channels->reg_classes; i++) {
276 		const struct p2p_reg_class *reg = &channels->reg_class[i];
277 		for (j = 0; j < reg->channels; j++) {
278 			if (p2p_channel_to_freq(reg->reg_class,
279 						reg->channel[j]) == (int) freq)
280 				return 1;
281 		}
282 	}
283 	return 0;
284 }
285 
286 
p2p_supported_freq(struct p2p_data * p2p,unsigned int freq)287 int p2p_supported_freq(struct p2p_data *p2p, unsigned int freq)
288 {
289 	u8 op_reg_class, op_channel;
290 	if (p2p_freq_to_channel(freq, &op_reg_class, &op_channel) < 0)
291 		return 0;
292 	return p2p_channels_includes(&p2p->cfg->channels, op_reg_class,
293 				     op_channel);
294 }
295 
296 
p2p_supported_freq_go(struct p2p_data * p2p,unsigned int freq)297 int p2p_supported_freq_go(struct p2p_data *p2p, unsigned int freq)
298 {
299 	u8 op_reg_class, op_channel;
300 	if (p2p_freq_to_channel(freq, &op_reg_class, &op_channel) < 0)
301 		return 0;
302 	return p2p_channels_includes(&p2p->cfg->channels, op_reg_class,
303 				     op_channel) &&
304 		!freq_range_list_includes(&p2p->no_go_freq, freq);
305 }
306 
307 
p2p_supported_freq_cli(struct p2p_data * p2p,unsigned int freq)308 int p2p_supported_freq_cli(struct p2p_data *p2p, unsigned int freq)
309 {
310 	u8 op_reg_class, op_channel;
311 	if (p2p_freq_to_channel(freq, &op_reg_class, &op_channel) < 0)
312 		return 0;
313 	return p2p_channels_includes(&p2p->cfg->channels, op_reg_class,
314 				     op_channel) ||
315 		p2p_channels_includes(&p2p->cfg->cli_channels, op_reg_class,
316 				      op_channel);
317 }
318 
319 
p2p_get_pref_freq(struct p2p_data * p2p,const struct p2p_channels * channels)320 unsigned int p2p_get_pref_freq(struct p2p_data *p2p,
321 			       const struct p2p_channels *channels)
322 {
323 	unsigned int i;
324 	int freq = 0;
325 	const struct p2p_channels *tmpc = channels ?
326 		channels : &p2p->cfg->channels;
327 
328 	if (tmpc == NULL)
329 		return 0;
330 
331 	for (i = 0; p2p->cfg->pref_chan && i < p2p->cfg->num_pref_chan; i++) {
332 		freq = p2p_channel_to_freq(p2p->cfg->pref_chan[i].op_class,
333 					   p2p->cfg->pref_chan[i].chan);
334 		if (p2p_channels_includes_freq(tmpc, freq))
335 			return freq;
336 	}
337 	return 0;
338 }
339 
340 
p2p_channels_dump(struct p2p_data * p2p,const char * title,const struct p2p_channels * chan)341 void p2p_channels_dump(struct p2p_data *p2p, const char *title,
342 		       const struct p2p_channels *chan)
343 {
344 	char buf[500], *pos, *end;
345 	size_t i, j;
346 	int ret;
347 
348 	pos = buf;
349 	end = pos + sizeof(buf);
350 
351 	for (i = 0; i < chan->reg_classes; i++) {
352 		const struct p2p_reg_class *c;
353 		c = &chan->reg_class[i];
354 		ret = os_snprintf(pos, end - pos, " %u:", c->reg_class);
355 		if (os_snprintf_error(end - pos, ret))
356 			break;
357 		pos += ret;
358 
359 		for (j = 0; j < c->channels; j++) {
360 			ret = os_snprintf(pos, end - pos, "%s%u",
361 					  j == 0 ? "" : ",",
362 					  c->channel[j]);
363 			if (os_snprintf_error(end - pos, ret))
364 				break;
365 			pos += ret;
366 		}
367 	}
368 	*pos = '\0';
369 
370 	p2p_dbg(p2p, "%s:%s", title, buf);
371 }
372 
373 
p2p_channel_pick_random(const u8 * channels,unsigned int num_channels)374 static u8 p2p_channel_pick_random(const u8 *channels, unsigned int num_channels)
375 {
376 	unsigned int r;
377 	if (os_get_random((u8 *) &r, sizeof(r)) < 0)
378 		r = 0;
379 	r %= num_channels;
380 	return channels[r];
381 }
382 
383 
p2p_channel_select(struct p2p_channels * chans,const int * classes,u8 * op_class,u8 * op_channel)384 int p2p_channel_select(struct p2p_channels *chans, const int *classes,
385 		       u8 *op_class, u8 *op_channel)
386 {
387 	unsigned int i, j;
388 
389 	for (j = 0; classes == NULL || classes[j]; j++) {
390 		for (i = 0; i < chans->reg_classes; i++) {
391 			struct p2p_reg_class *c = &chans->reg_class[i];
392 
393 			if (c->channels == 0)
394 				continue;
395 
396 			if (classes == NULL || c->reg_class == classes[j]) {
397 				/*
398 				 * Pick one of the available channels in the
399 				 * operating class at random.
400 				 */
401 				*op_class = c->reg_class;
402 				*op_channel = p2p_channel_pick_random(
403 					c->channel, c->channels);
404 				return 0;
405 			}
406 		}
407 		if (classes == NULL)
408 			break;
409 	}
410 
411 	return -1;
412 }
413 
414 
p2p_channel_random_social(struct p2p_channels * chans,u8 * op_class,u8 * op_channel)415 int p2p_channel_random_social(struct p2p_channels *chans, u8 *op_class,
416 			      u8 *op_channel)
417 {
418 	u8 chan[4];
419 	unsigned int num_channels = 0;
420 
421 	/* Try to find available social channels from 2.4 GHz */
422 	if (p2p_channels_includes(chans, 81, 1))
423 		chan[num_channels++] = 1;
424 	if (p2p_channels_includes(chans, 81, 6))
425 		chan[num_channels++] = 6;
426 	if (p2p_channels_includes(chans, 81, 11))
427 		chan[num_channels++] = 11;
428 
429 	/* Try to find available social channels from 60 GHz */
430 	if (p2p_channels_includes(chans, 180, 2))
431 		chan[num_channels++] = 2;
432 
433 	if (num_channels == 0)
434 		return -1;
435 
436 	*op_channel = p2p_channel_pick_random(chan, num_channels);
437 	if (*op_channel == 2)
438 		*op_class = 180;
439 	else
440 		*op_class = 81;
441 
442 	return 0;
443 }
444 
445 
p2p_channels_to_freqs(const struct p2p_channels * channels,int * freq_list,unsigned int max_len)446 int p2p_channels_to_freqs(const struct p2p_channels *channels, int *freq_list,
447 			  unsigned int max_len)
448 {
449 	unsigned int i, idx;
450 
451 	if (!channels || max_len == 0)
452 		return 0;
453 
454 	for (i = 0, idx = 0; i < channels->reg_classes; i++) {
455 		const struct p2p_reg_class *c = &channels->reg_class[i];
456 		unsigned int j;
457 
458 		if (idx + 1 == max_len)
459 			break;
460 		for (j = 0; j < c->channels; j++) {
461 			int freq;
462 			unsigned int k;
463 
464 			if (idx + 1 == max_len)
465 				break;
466 			freq = p2p_channel_to_freq(c->reg_class,
467 						   c->channel[j]);
468 			if (freq < 0)
469 				continue;
470 
471 			for (k = 0; k < idx; k++) {
472 				if (freq_list[k] == freq)
473 					break;
474 			}
475 
476 			if (k < idx)
477 				continue;
478 			freq_list[idx++] = freq;
479 		}
480 	}
481 
482 	freq_list[idx] = 0;
483 
484 	return idx;
485 }
486