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 static u8 eir_append_name(u8 *eir, u16 eir_len, u8 type, u8 *data, u8 data_len)
  17 {
  18         u8 name[HCI_MAX_SHORT_NAME_LENGTH + 1];
  19
  20         /* If data is already NULL terminated just pass it directly */
  21         if (data[data_len - 1] == '\0')
  22                 return eir_append_data(eir, eir_len, type, data, data_len);
  23
  24         memcpy(name, data, HCI_MAX_SHORT_NAME_LENGTH);
  25         name[HCI_MAX_SHORT_NAME_LENGTH] = '\0';
  26
  27         return eir_append_data(eir, eir_len, type, name, sizeof(name));
  28 }
  29
  30 u8 eir_append_local_name(struct hci_dev *hdev, u8 *ptr, u8 ad_len)
  31 {
  32         size_t short_len;
  33         size_t complete_len;
  34
  35         /* no space left for name (+ NULL + type + len) */
  36         if ((HCI_MAX_AD_LENGTH - ad_len) < HCI_MAX_SHORT_NAME_LENGTH + 3)
  37                 return ad_len;
  38
  39         /* use complete name if present and fits */
  40         complete_len = strnlen(hdev->dev_name, sizeof(hdev->dev_name));
  41         if (complete_len && complete_len <= HCI_MAX_SHORT_NAME_LENGTH)
  42                 return eir_append_name(ptr, ad_len, EIR_NAME_COMPLETE,
  43                                        hdev->dev_name, complete_len + 1);
  44
  45         /* use short name if present */
  46         short_len = strnlen(hdev->short_name, sizeof(hdev->short_name));
  47         if (short_len)
  48                 return eir_append_name(ptr, ad_len, EIR_NAME_SHORT,
  49                                        hdev->short_name,
  50                                        short_len == HCI_MAX_SHORT_NAME_LENGTH ?
  51                                        short_len : short_len + 1);
  52
  53         /* use shortened full name if present, we already know that name
  54          * is longer then HCI_MAX_SHORT_NAME_LENGTH
  55          */
  56         if (complete_len)
  57                 return eir_append_name(ptr, ad_len, EIR_NAME_SHORT,
  58                                        hdev->dev_name,
  59                                        HCI_MAX_SHORT_NAME_LENGTH);
  60
  61         return ad_len;
  62 }
  63
  64 u8 eir_append_appearance(struct hci_dev *hdev, u8 *ptr, u8 ad_len)
  65 {
  66         return eir_append_le16(ptr, ad_len, EIR_APPEARANCE, hdev->appearance);
  67 }
  68
  69 u8 eir_append_service_data(u8 *eir, u16 eir_len, u16 uuid, u8 *data,
  70                            u8 data_len)
  71 {
  72         eir[eir_len++] = sizeof(u8) + sizeof(uuid) + data_len;
  73         eir[eir_len++] = EIR_SERVICE_DATA;
  74         put_unaligned_le16(uuid, &eir[eir_len]);
  75         eir_len += sizeof(uuid);
  76         memcpy(&eir[eir_len], data, data_len);
  77         eir_len += data_len;
  78
  79         return eir_len;
  80 }
  81
  82 static u8 *create_uuid16_list(struct hci_dev *hdev, u8 *data, ptrdiff_t len)
  83 {
  84         u8 *ptr = data, *uuids_start = NULL;
  85         struct bt_uuid *uuid;
  86
  87         if (len < 4)
  88                 return ptr;
  89
  90         list_for_each_entry(uuid, &hdev->uuids, list) {
  91                 u16 uuid16;
  92
  93                 if (uuid->size != 16)
  94                         continue;
  95
  96                 uuid16 = get_unaligned_le16(&uuid->uuid[12]);
  97                 if (uuid16 < 0x1100)
  98                         continue;
  99
 100                 if (uuid16 == PNP_INFO_SVCLASS_ID)
 101                         continue;
 102
 103                 if (!uuids_start) {
 104                         uuids_start = ptr;
 105                         uuids_start[0] = 1;
 106                         uuids_start[1] = EIR_UUID16_ALL;
 107                         ptr += 2;
 108                 }
 109
 110                 /* Stop if not enough space to put next UUID */
 111                 if ((ptr - data) + sizeof(u16) > len) {
 112                         uuids_start[1] = EIR_UUID16_SOME;
 113                         break;
 114                 }
 115
 116                 *ptr++ = (uuid16 & 0x00ff);
 117                 *ptr++ = (uuid16 & 0xff00) >> 8;
 118                 uuids_start[0] += sizeof(uuid16);
 119         }
 120
 121         return ptr;
 122 }
 123
 124 static u8 *create_uuid32_list(struct hci_dev *hdev, u8 *data, ptrdiff_t len)
 125 {
 126         u8 *ptr = data, *uuids_start = NULL;
 127         struct bt_uuid *uuid;
 128
 129         if (len < 6)
 130                 return ptr;
 131
 132         list_for_each_entry(uuid, &hdev->uuids, list) {
 133                 if (uuid->size != 32)
 134                         continue;
 135
 136                 if (!uuids_start) {
 137                         uuids_start = ptr;
 138                         uuids_start[0] = 1;
 139                         uuids_start[1] = EIR_UUID32_ALL;
 140                         ptr += 2;
 141                 }
 142
 143                 /* Stop if not enough space to put next UUID */
 144                 if ((ptr - data) + sizeof(u32) > len) {
 145                         uuids_start[1] = EIR_UUID32_SOME;
 146                         break;
 147                 }
 148
 149                 memcpy(ptr, &uuid->uuid[12], sizeof(u32));
 150                 ptr += sizeof(u32);
 151                 uuids_start[0] += sizeof(u32);
 152         }
 153
 154         return ptr;
 155 }
 156
 157 static u8 *create_uuid128_list(struct hci_dev *hdev, u8 *data, ptrdiff_t len)
 158 {
 159         u8 *ptr = data, *uuids_start = NULL;
 160         struct bt_uuid *uuid;
 161
 162         if (len < 18)
 163                 return ptr;
 164
 165         list_for_each_entry(uuid, &hdev->uuids, list) {
 166                 if (uuid->size != 128)
 167                         continue;
 168
 169                 if (!uuids_start) {
 170                         uuids_start = ptr;
 171                         uuids_start[0] = 1;
 172                         uuids_start[1] = EIR_UUID128_ALL;
 173                         ptr += 2;
 174                 }
 175
 176                 /* Stop if not enough space to put next UUID */
 177                 if ((ptr - data) + 16 > len) {
 178                         uuids_start[1] = EIR_UUID128_SOME;
 179                         break;
 180                 }
 181
 182                 memcpy(ptr, uuid->uuid, 16);
 183                 ptr += 16;
 184                 uuids_start[0] += 16;
 185         }
 186
 187         return ptr;
 188 }
 189
 190 void eir_create(struct hci_dev *hdev, u8 *data)
 191 {
 192         u8 *ptr = data;
 193         size_t name_len;
 194
 195         name_len = strnlen(hdev->dev_name, sizeof(hdev->dev_name));
 196
 197         if (name_len > 0) {
 198                 /* EIR Data type */
 199                 if (name_len > 48) {
 200                         name_len = 48;
 201                         ptr[1] = EIR_NAME_SHORT;
 202                 } else {
 203                         ptr[1] = EIR_NAME_COMPLETE;
 204                 }
 205
 206                 /* EIR Data length */
 207                 ptr[0] = name_len + 1;
 208
 209                 memcpy(ptr + 2, hdev->dev_name, name_len);
 210
 211                 ptr += (name_len + 2);
 212         }
 213
 214         if (hdev->inq_tx_power != HCI_TX_POWER_INVALID) {
 215                 ptr[0] = 2;
 216                 ptr[1] = EIR_TX_POWER;
 217                 ptr[2] = (u8)hdev->inq_tx_power;
 218
 219                 ptr += 3;
 220         }
 221
 222         if (hdev->devid_source > 0) {
 223                 ptr[0] = 9;
 224                 ptr[1] = EIR_DEVICE_ID;
 225
 226                 put_unaligned_le16(hdev->devid_source, ptr + 2);
 227                 put_unaligned_le16(hdev->devid_vendor, ptr + 4);
 228                 put_unaligned_le16(hdev->devid_product, ptr + 6);
 229                 put_unaligned_le16(hdev->devid_version, ptr + 8);
 230
 231                 ptr += 10;
 232         }
 233
 234         ptr = create_uuid16_list(hdev, ptr, HCI_MAX_EIR_LENGTH - (ptr - data));
 235         ptr = create_uuid32_list(hdev, ptr, HCI_MAX_EIR_LENGTH - (ptr - data));
 236         ptr = create_uuid128_list(hdev, ptr, HCI_MAX_EIR_LENGTH - (ptr - data));
 237 }
 238
 239 u8 eir_create_per_adv_data(struct hci_dev *hdev, u8 instance, u8 *ptr)
 240 {
 241         struct adv_info *adv = NULL;
 242         u8 ad_len = 0;
 243
 244         /* Return 0 when the current instance identifier is invalid. */
 245         if (instance) {
 246                 adv = hci_find_adv_instance(hdev, instance);
 247                 if (!adv)
 248                         return 0;
 249         }
 250
 251         if (adv) {
 252                 memcpy(ptr, adv->per_adv_data, adv->per_adv_data_len);
 253                 ad_len += adv->per_adv_data_len;
 254                 ptr += adv->per_adv_data_len;
 255         }
 256
 257         return ad_len;
 258 }
 259
 260 u8 eir_create_adv_data(struct hci_dev *hdev, u8 instance, u8 *ptr)
 261 {
 262         struct adv_info *adv = NULL;
 263         u8 ad_len = 0, flags = 0;
 264         u32 instance_flags;
 265
 266         /* Return 0 when the current instance identifier is invalid. */
 267         if (instance) {
 268                 adv = hci_find_adv_instance(hdev, instance);
 269                 if (!adv)
 270                         return 0;
 271         }
 272
 273         instance_flags = hci_adv_instance_flags(hdev, instance);
 274
 275         /* If instance already has the flags set skip adding it once
 276          * again.
 277          */
 278         if (adv && eir_get_data(adv->adv_data, adv->adv_data_len, EIR_FLAGS,
 279                                 NULL))
 280                 goto skip_flags;
 281
 282         /* The Add Advertising command allows userspace to set both the general
 283          * and limited discoverable flags.
 284          */
 285         if (instance_flags & MGMT_ADV_FLAG_DISCOV)
 286                 flags |= LE_AD_GENERAL;
 287
 288         if (instance_flags & MGMT_ADV_FLAG_LIMITED_DISCOV)
 289                 flags |= LE_AD_LIMITED;
 290
 291         if (!hci_dev_test_flag(hdev, HCI_BREDR_ENABLED))
 292                 flags |= LE_AD_NO_BREDR;
 293
 294         if (flags || (instance_flags & MGMT_ADV_FLAG_MANAGED_FLAGS)) {
 295                 /* If a discovery flag wasn't provided, simply use the global
 296                  * settings.
 297                  */
 298                 if (!flags)
 299                         flags |= mgmt_get_adv_discov_flags(hdev);
 300
 301                 /* If flags would still be empty, then there is no need to
 302                  * include the "Flags" AD field".
 303                  */
 304                 if (flags) {
 305                         ptr[0] = 0x02;
 306                         ptr[1] = EIR_FLAGS;
 307                         ptr[2] = flags;
 308
 309                         ad_len += 3;
 310                         ptr += 3;
 311                 }
 312         }
 313
 314 skip_flags:
 315         if (adv) {
 316                 memcpy(ptr, adv->adv_data, adv->adv_data_len);
 317                 ad_len += adv->adv_data_len;
 318                 ptr += adv->adv_data_len;
 319         }
 320
 321         if (instance_flags & MGMT_ADV_FLAG_TX_POWER) {
 322                 s8 adv_tx_power;
 323
 324                 if (ext_adv_capable(hdev)) {
 325                         if (adv)
 326                                 adv_tx_power = adv->tx_power;
 327                         else
 328                                 adv_tx_power = hdev->adv_tx_power;
 329                 } else {
 330                         adv_tx_power = hdev->adv_tx_power;
 331                 }
 332
 333                 /* Provide Tx Power only if we can provide a valid value for it */
 334                 if (adv_tx_power != HCI_TX_POWER_INVALID) {
 335                         ptr[0] = 0x02;
 336                         ptr[1] = EIR_TX_POWER;
 337                         ptr[2] = (u8)adv_tx_power;
 338
 339                         ad_len += 3;
 340                         ptr += 3;
 341                 }
 342         }
 343
 344         return ad_len;
 345 }
 346
 347 static u8 create_default_scan_rsp(struct hci_dev *hdev, u8 *ptr)
 348 {
 349         u8 scan_rsp_len = 0;
 350
 351         if (hdev->appearance)
 352                 scan_rsp_len = eir_append_appearance(hdev, ptr, scan_rsp_len);
 353
 354         return eir_append_local_name(hdev, ptr, scan_rsp_len);
 355 }
 356
 357 u8 eir_create_scan_rsp(struct hci_dev *hdev, u8 instance, u8 *ptr)
 358 {
 359         struct adv_info *adv;
 360         u8 scan_rsp_len = 0;
 361
 362         if (!instance)
 363                 return create_default_scan_rsp(hdev, ptr);
 364
 365         adv = hci_find_adv_instance(hdev, instance);
 366         if (!adv)
 367                 return 0;
 368
 369         if ((adv->flags & MGMT_ADV_FLAG_APPEARANCE) && hdev->appearance)
 370                 scan_rsp_len = eir_append_appearance(hdev, ptr, scan_rsp_len);
 371
 372         memcpy(&ptr[scan_rsp_len], adv->scan_rsp_data, adv->scan_rsp_len);
 373
 374         scan_rsp_len += adv->scan_rsp_len;
 375
 376         if (adv->flags & MGMT_ADV_FLAG_LOCAL_NAME)
 377                 scan_rsp_len = eir_append_local_name(hdev, ptr, scan_rsp_len);
 378
 379         return scan_rsp_len;
 380 }
 381
 382 void *eir_get_service_data(u8 *eir, size_t eir_len, u16 uuid, size_t *len)
 383 {
 384         while ((eir = eir_get_data(eir, eir_len, EIR_SERVICE_DATA, len))) {
 385                 u16 value = get_unaligned_le16(eir);
 386
 387                 if (uuid == value) {
 388                         if (len)
 389                                 *len -= 2;
 390                         return &eir[2];
 391                 }
 392
 393                 eir += *len;
 394                 eir_len -= *len;
 395         }
 396
 397         return NULL;
 398 }