net/bluetooth/eir.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * BlueZ - Bluetooth protocol stack for Linux
   4  *
   5  * Copyright (C) 2021 Intel Corporation
   6  */
   7
   8 #include <net/bluetooth/bluetooth.h>
   9 #include <net/bluetooth/hci_core.h>
  10 #include <net/bluetooth/mgmt.h>
  11
  12 #include "eir.h"
  13
  14 #define PNP_INFO_SVCLASS_ID             0x1200
  15
  16 u8 eir_append_local_name(struct hci_dev *hdev, u8 *ptr, u8 ad_len)
  17 {
  18         size_t short_len;
  19         size_t complete_len;
  20
  21         /* no space left for name (+ type + len) */
  22         if ((max_adv_len(hdev) - ad_len) < HCI_MAX_SHORT_NAME_LENGTH + 2)
  23                 return ad_len;
  24
  25         /* use complete name if present and fits */
  26         complete_len = strnlen(hdev->dev_name, sizeof(hdev->dev_name));
  27         if (complete_len && complete_len <= HCI_MAX_SHORT_NAME_LENGTH)
  28                 return eir_append_data(ptr, ad_len, EIR_NAME_COMPLETE,
  29                                        hdev->dev_name, complete_len);
  30
  31         /* use short name if present */
  32         short_len = strnlen(hdev->short_name, sizeof(hdev->short_name));
  33         if (short_len)
  34                 return eir_append_data(ptr, ad_len, EIR_NAME_SHORT,
  35                                        hdev->short_name,
  36                                        short_len);
  37
  38         /* use shortened full name if present, we already know that name
  39          * is longer then HCI_MAX_SHORT_NAME_LENGTH
  40          */
  41         if (complete_len)
  42                 return eir_append_data(ptr, ad_len, EIR_NAME_SHORT,
  43                                        hdev->dev_name,
  44                                        HCI_MAX_SHORT_NAME_LENGTH);
  45
  46         return ad_len;
  47 }
  48
  49 u8 eir_append_appearance(struct hci_dev *hdev, u8 *ptr, u8 ad_len)
  50 {
  51         return eir_append_le16(ptr, ad_len, EIR_APPEARANCE, hdev->appearance);
  52 }
  53
  54 u8 eir_append_service_data(u8 *eir, u16 eir_len, u16 uuid, u8 *data,
  55                            u8 data_len)
  56 {
  57         eir[eir_len++] = sizeof(u8) + sizeof(uuid) + data_len;
  58         eir[eir_len++] = EIR_SERVICE_DATA;
  59         put_unaligned_le16(uuid, &eir[eir_len]);
  60         eir_len += sizeof(uuid);
  61         memcpy(&eir[eir_len], data, data_len);
  62         eir_len += data_len;
  63
  64         return eir_len;
  65 }
  66
  67 static u8 *create_uuid16_list(struct hci_dev *hdev, u8 *data, ptrdiff_t len)
  68 {
  69         u8 *ptr = data, *uuids_start = NULL;
  70         struct bt_uuid *uuid;
  71
  72         if (len < 4)
  73                 return ptr;
  74
  75         list_for_each_entry(uuid, &hdev->uuids, list) {
  76                 u16 uuid16;
  77
  78                 if (uuid->size != 16)
  79                         continue;
  80
  81                 uuid16 = get_unaligned_le16(&uuid->uuid[12]);
  82                 if (uuid16 < 0x1100)
  83                         continue;
  84
  85                 if (uuid16 == PNP_INFO_SVCLASS_ID)
  86                         continue;
  87
  88                 if (!uuids_start) {
  89                         uuids_start = ptr;
  90                         uuids_start[0] = 1;
  91                         uuids_start[1] = EIR_UUID16_ALL;
  92                         ptr += 2;
  93                 }
  94
  95                 /* Stop if not enough space to put next UUID */
  96                 if ((ptr - data) + sizeof(u16) > len) {
  97                         uuids_start[1] = EIR_UUID16_SOME;
  98                         break;
  99                 }
 100
 101                 *ptr++ = (uuid16 & 0x00ff);
 102                 *ptr++ = (uuid16 & 0xff00) >> 8;
 103                 uuids_start[0] += sizeof(uuid16);
 104         }
 105
 106         return ptr;
 107 }
 108
 109 static u8 *create_uuid32_list(struct hci_dev *hdev, u8 *data, ptrdiff_t len)
 110 {
 111         u8 *ptr = data, *uuids_start = NULL;
 112         struct bt_uuid *uuid;
 113
 114         if (len < 6)
 115                 return ptr;
 116
 117         list_for_each_entry(uuid, &hdev->uuids, list) {
 118                 if (uuid->size != 32)
 119                         continue;
 120
 121                 if (!uuids_start) {
 122                         uuids_start = ptr;
 123                         uuids_start[0] = 1;
 124                         uuids_start[1] = EIR_UUID32_ALL;
 125                         ptr += 2;
 126                 }
 127
 128                 /* Stop if not enough space to put next UUID */
 129                 if ((ptr - data) + sizeof(u32) > len) {
 130                         uuids_start[1] = EIR_UUID32_SOME;
 131                         break;
 132                 }
 133
 134                 memcpy(ptr, &uuid->uuid[12], sizeof(u32));
 135                 ptr += sizeof(u32);
 136                 uuids_start[0] += sizeof(u32);
 137         }
 138
 139         return ptr;
 140 }
 141
 142 static u8 *create_uuid128_list(struct hci_dev *hdev, u8 *data, ptrdiff_t len)
 143 {
 144         u8 *ptr = data, *uuids_start = NULL;
 145         struct bt_uuid *uuid;
 146
 147         if (len < 18)
 148                 return ptr;
 149
 150         list_for_each_entry(uuid, &hdev->uuids, list) {
 151                 if (uuid->size != 128)
 152                         continue;
 153
 154                 if (!uuids_start) {
 155                         uuids_start = ptr;
 156                         uuids_start[0] = 1;
 157                         uuids_start[1] = EIR_UUID128_ALL;
 158                         ptr += 2;
 159                 }
 160
 161                 /* Stop if not enough space to put next UUID */
 162                 if ((ptr - data) + 16 > len) {
 163                         uuids_start[1] = EIR_UUID128_SOME;
 164                         break;
 165                 }
 166
 167                 memcpy(ptr, uuid->uuid, 16);
 168                 ptr += 16;
 169                 uuids_start[0] += 16;
 170         }
 171
 172         return ptr;
 173 }
 174
 175 void eir_create(struct hci_dev *hdev, u8 *data)
 176 {
 177         u8 *ptr = data;
 178         size_t name_len;
 179
 180         name_len = strnlen(hdev->dev_name, sizeof(hdev->dev_name));
 181
 182         if (name_len > 0) {
 183                 /* EIR Data type */
 184                 if (name_len > 48) {
 185                         name_len = 48;
 186                         ptr[1] = EIR_NAME_SHORT;
 187                 } else {
 188                         ptr[1] = EIR_NAME_COMPLETE;
 189                 }
 190
 191                 /* EIR Data length */
 192                 ptr[0] = name_len + 1;
 193
 194                 memcpy(ptr + 2, hdev->dev_name, name_len);
 195
 196                 ptr += (name_len + 2);
 197         }
 198
 199         if (hdev->inq_tx_power != HCI_TX_POWER_INVALID) {
 200                 ptr[0] = 2;
 201                 ptr[1] = EIR_TX_POWER;
 202                 ptr[2] = (u8)hdev->inq_tx_power;
 203
 204                 ptr += 3;
 205         }
 206
 207         if (hdev->devid_source > 0) {
 208                 ptr[0] = 9;
 209                 ptr[1] = EIR_DEVICE_ID;
 210
 211                 put_unaligned_le16(hdev->devid_source, ptr + 2);
 212                 put_unaligned_le16(hdev->devid_vendor, ptr + 4);
 213                 put_unaligned_le16(hdev->devid_product, ptr + 6);
 214                 put_unaligned_le16(hdev->devid_version, ptr + 8);
 215
 216                 ptr += 10;
 217         }
 218
 219         ptr = create_uuid16_list(hdev, ptr, HCI_MAX_EIR_LENGTH - (ptr - data));
 220         ptr = create_uuid32_list(hdev, ptr, HCI_MAX_EIR_LENGTH - (ptr - data));
 221         ptr = create_uuid128_list(hdev, ptr, HCI_MAX_EIR_LENGTH - (ptr - data));
 222 }
 223
 224 u8 eir_create_per_adv_data(struct hci_dev *hdev, u8 instance, u8 *ptr)
 225 {
 226         struct adv_info *adv = NULL;
 227         u8 ad_len = 0;
 228
 229         /* Return 0 when the current instance identifier is invalid. */
 230         if (instance) {
 231                 adv = hci_find_adv_instance(hdev, instance);
 232                 if (!adv)
 233                         return 0;
 234         }
 235
 236         if (adv) {
 237                 memcpy(ptr, adv->per_adv_data, adv->per_adv_data_len);
 238                 ad_len += adv->per_adv_data_len;
 239                 ptr += adv->per_adv_data_len;
 240         }
 241
 242         return ad_len;
 243 }
 244
 245 u8 eir_create_adv_data(struct hci_dev *hdev, u8 instance, u8 *ptr)
 246 {
 247         struct adv_info *adv = NULL;
 248         u8 ad_len = 0, flags = 0;
 249         u32 instance_flags;
 250
 251         /* Return 0 when the current instance identifier is invalid. */
 252         if (instance) {
 253                 adv = hci_find_adv_instance(hdev, instance);
 254                 if (!adv)
 255                         return 0;
 256         }
 257
 258         instance_flags = hci_adv_instance_flags(hdev, instance);
 259
 260         /* If instance already has the flags set skip adding it once
 261          * again.
 262          */
 263         if (adv && eir_get_data(adv->adv_data, adv->adv_data_len, EIR_FLAGS,
 264                                 NULL))
 265                 goto skip_flags;
 266
 267         /* The Add Advertising command allows userspace to set both the general
 268          * and limited discoverable flags.
 269          */
 270         if (instance_flags & MGMT_ADV_FLAG_DISCOV)
 271                 flags |= LE_AD_GENERAL;
 272
 273         if (instance_flags & MGMT_ADV_FLAG_LIMITED_DISCOV)
 274                 flags |= LE_AD_LIMITED;
 275
 276         if (!hci_dev_test_flag(hdev, HCI_BREDR_ENABLED))
 277                 flags |= LE_AD_NO_BREDR;
 278
 279         if (flags || (instance_flags & MGMT_ADV_FLAG_MANAGED_FLAGS)) {
 280                 /* If a discovery flag wasn't provided, simply use the global
 281                  * settings.
 282                  */
 283                 if (!flags)
 284                         flags |= mgmt_get_adv_discov_flags(hdev);
 285
 286                 /* If flags would still be empty, then there is no need to
 287                  * include the "Flags" AD field".
 288                  */
 289                 if (flags) {
 290                         ptr[0] = 0x02;
 291                         ptr[1] = EIR_FLAGS;
 292                         ptr[2] = flags;
 293
 294                         ad_len += 3;
 295                         ptr += 3;
 296                 }
 297         }
 298
 299 skip_flags:
 300         if (adv) {
 301                 memcpy(ptr, adv->adv_data, adv->adv_data_len);
 302                 ad_len += adv->adv_data_len;
 303                 ptr += adv->adv_data_len;
 304         }
 305
 306         if (instance_flags & MGMT_ADV_FLAG_TX_POWER) {
 307                 s8 adv_tx_power;
 308
 309                 if (ext_adv_capable(hdev)) {
 310                         if (adv)
 311                                 adv_tx_power = adv->tx_power;
 312                         else
 313                                 adv_tx_power = hdev->adv_tx_power;
 314                 } else {
 315                         adv_tx_power = hdev->adv_tx_power;
 316                 }
 317
 318                 /* Provide Tx Power only if we can provide a valid value for it */
 319                 if (adv_tx_power != HCI_TX_POWER_INVALID) {
 320                         ptr[0] = 0x02;
 321                         ptr[1] = EIR_TX_POWER;
 322                         ptr[2] = (u8)adv_tx_power;
 323
 324                         ad_len += 3;
 325                         ptr += 3;
 326                 }
 327         }
 328
 329         return ad_len;
 330 }
 331
 332 static u8 create_default_scan_rsp(struct hci_dev *hdev, u8 *ptr)
 333 {
 334         u8 scan_rsp_len = 0;
 335
 336         if (hdev->appearance)
 337                 scan_rsp_len = eir_append_appearance(hdev, ptr, scan_rsp_len);
 338
 339         return eir_append_local_name(hdev, ptr, scan_rsp_len);
 340 }
 341
 342 u8 eir_create_scan_rsp(struct hci_dev *hdev, u8 instance, u8 *ptr)
 343 {
 344         struct adv_info *adv;
 345         u8 scan_rsp_len = 0;
 346
 347         if (!instance)
 348                 return create_default_scan_rsp(hdev, ptr);
 349
 350         adv = hci_find_adv_instance(hdev, instance);
 351         if (!adv)
 352                 return 0;
 353
 354         if ((adv->flags & MGMT_ADV_FLAG_APPEARANCE) && hdev->appearance)
 355                 scan_rsp_len = eir_append_appearance(hdev, ptr, scan_rsp_len);
 356
 357         memcpy(&ptr[scan_rsp_len], adv->scan_rsp_data, adv->scan_rsp_len);
 358
 359         scan_rsp_len += adv->scan_rsp_len;
 360
 361         if (adv->flags & MGMT_ADV_FLAG_LOCAL_NAME)
 362                 scan_rsp_len = eir_append_local_name(hdev, ptr, scan_rsp_len);
 363
 364         return scan_rsp_len;
 365 }
 366
 367 void *eir_get_service_data(u8 *eir, size_t eir_len, u16 uuid, size_t *len)
 368 {
 369         while ((eir = eir_get_data(eir, eir_len, EIR_SERVICE_DATA, len))) {
 370                 u16 value = get_unaligned_le16(eir);
 371
 372                 if (uuid == value) {
 373                         if (len)
 374                                 *len -= 2;
 375                         return &eir[2];
 376                 }
 377
 378                 eir += *len;
 379                 eir_len -= *len;
 380         }
 381
 382         return NULL;
 383 }