p2p_utils.c revision 44c957860ca714a86357591f39aff0bfa904c743
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 */ 24int 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 */ 55int 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 } 98 return -1; 99} 100 101 102/** 103 * p2p_freq_to_channel - Convert frequency into channel info 104 * @op_class: Buffer for returning operating class 105 * @channel: Buffer for returning channel number 106 * Returns: 0 on success, -1 if the specified frequency is unknown 107 */ 108int p2p_freq_to_channel(unsigned int freq, u8 *op_class, u8 *channel) 109{ 110 /* TODO: more operating classes */ 111 if (freq >= 2412 && freq <= 2472) { 112 *op_class = 81; /* 2.407 GHz, channels 1..13 */ 113 *channel = (freq - 2407) / 5; 114 return 0; 115 } 116 117 if (freq == 2484) { 118 *op_class = 82; /* channel 14 */ 119 *channel = 14; 120 return 0; 121 } 122 123 if (freq >= 5180 && freq <= 5240) { 124 *op_class = 115; /* 5 GHz, channels 36..48 */ 125 *channel = (freq - 5000) / 5; 126 return 0; 127 } 128 129 if (freq >= 5745 && freq <= 5805) { 130 *op_class = 124; /* 5 GHz, channels 149..161 */ 131 *channel = (freq - 5000) / 5; 132 return 0; 133 } 134 135 return -1; 136} 137 138 139static void p2p_reg_class_intersect(const struct p2p_reg_class *a, 140 const struct p2p_reg_class *b, 141 struct p2p_reg_class *res) 142{ 143 size_t i, j; 144 145 res->reg_class = a->reg_class; 146 147 for (i = 0; i < a->channels; i++) { 148 for (j = 0; j < b->channels; j++) { 149 if (a->channel[i] != b->channel[j]) 150 continue; 151 res->channel[res->channels] = a->channel[i]; 152 res->channels++; 153 if (res->channels == P2P_MAX_REG_CLASS_CHANNELS) 154 return; 155 } 156 } 157} 158 159 160/** 161 * p2p_channels_intersect - Intersection of supported channel lists 162 * @a: First set of supported channels 163 * @b: Second set of supported channels 164 * @res: Data structure for returning the intersection of support channels 165 * 166 * This function can be used to find a common set of supported channels. Both 167 * input channels sets are assumed to use the same country code. If different 168 * country codes are used, the regulatory class numbers may not be matched 169 * correctly and results are undefined. 170 */ 171void p2p_channels_intersect(const struct p2p_channels *a, 172 const struct p2p_channels *b, 173 struct p2p_channels *res) 174{ 175 size_t i, j; 176 177 os_memset(res, 0, sizeof(*res)); 178 179 for (i = 0; i < a->reg_classes; i++) { 180 const struct p2p_reg_class *a_reg = &a->reg_class[i]; 181 for (j = 0; j < b->reg_classes; j++) { 182 const struct p2p_reg_class *b_reg = &b->reg_class[j]; 183 if (a_reg->reg_class != b_reg->reg_class) 184 continue; 185 p2p_reg_class_intersect( 186 a_reg, b_reg, 187 &res->reg_class[res->reg_classes]); 188 if (res->reg_class[res->reg_classes].channels) { 189 res->reg_classes++; 190 if (res->reg_classes == P2P_MAX_REG_CLASSES) 191 return; 192 } 193 } 194 } 195} 196 197 198/** 199 * p2p_channels_includes - Check whether a channel is included in the list 200 * @channels: List of supported channels 201 * @reg_class: Regulatory class of the channel to search 202 * @channel: Channel number of the channel to search 203 * Returns: 1 if channel was found or 0 if not 204 */ 205int p2p_channels_includes(const struct p2p_channels *channels, u8 reg_class, 206 u8 channel) 207{ 208 size_t i, j; 209 for (i = 0; i < channels->reg_classes; i++) { 210 const struct p2p_reg_class *reg = &channels->reg_class[i]; 211 if (reg->reg_class != reg_class) 212 continue; 213 for (j = 0; j < reg->channels; j++) { 214 if (reg->channel[j] == channel) 215 return 1; 216 } 217 } 218 return 0; 219} 220 221 222int p2p_channels_includes_freq(const struct p2p_channels *channels, 223 unsigned int freq) 224{ 225 size_t i, j; 226 for (i = 0; i < channels->reg_classes; i++) { 227 const struct p2p_reg_class *reg = &channels->reg_class[i]; 228 for (j = 0; j < reg->channels; j++) { 229 if (p2p_channel_to_freq(reg->reg_class, 230 reg->channel[j]) == (int) freq) 231 return 1; 232 } 233 } 234 return 0; 235} 236 237 238int p2p_supported_freq(struct p2p_data *p2p, unsigned int freq) 239{ 240 u8 op_reg_class, op_channel; 241 if (p2p_freq_to_channel(freq, &op_reg_class, &op_channel) < 0) 242 return 0; 243 return p2p_channels_includes(&p2p->cfg->channels, op_reg_class, 244 op_channel); 245} 246 247 248unsigned int p2p_get_pref_freq(struct p2p_data *p2p, 249 const struct p2p_channels *channels) 250{ 251 unsigned int i; 252 int freq = 0; 253 254 if (channels == NULL) { 255 if (p2p->cfg->num_pref_chan) { 256 freq = p2p_channel_to_freq( 257 p2p->cfg->pref_chan[0].op_class, 258 p2p->cfg->pref_chan[0].chan); 259 if (freq < 0) 260 freq = 0; 261 } 262 return freq; 263 } 264 265 for (i = 0; p2p->cfg->pref_chan && i < p2p->cfg->num_pref_chan; i++) { 266 freq = p2p_channel_to_freq(p2p->cfg->pref_chan[i].op_class, 267 p2p->cfg->pref_chan[i].chan); 268 if (p2p_channels_includes_freq(channels, freq)) 269 return freq; 270 } 271 272 return 0; 273} 274