// SPDX-License-Identifier: GPL-2.0
/*
 * BlueZ - Bluetooth protocol stack for Linux
 *
 * Copyright (C) 2021 Intel Corporation
 */

#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>
#include <net/bluetooth/mgmt.h>

#include "eir.h"

#define PNP_INFO_SVCLASS_ID             0x1200

u8 eir_append_local_name(struct hci_dev *hdev, u8 *ptr, u8 ad_len)
{
        size_t short_len;
        size_t complete_len;

        /* no space left for name (+ type + len) */
        if ((max_adv_len(hdev) - ad_len) < HCI_MAX_SHORT_NAME_LENGTH + 2)
                return ad_len;

        /* use complete name if present and fits */
        complete_len = strnlen(hdev->dev_name, sizeof(hdev->dev_name));
        if (complete_len && complete_len <= HCI_MAX_SHORT_NAME_LENGTH)
                return eir_append_data(ptr, ad_len, EIR_NAME_COMPLETE,
                                       hdev->dev_name, complete_len);

        /* use short name if present */
        short_len = strnlen(hdev->short_name, sizeof(hdev->short_name));
        if (short_len)
                return eir_append_data(ptr, ad_len, EIR_NAME_SHORT,
                                       hdev->short_name,
                                       short_len);

        /* use shortened full name if present, we already know that name
         * is longer then HCI_MAX_SHORT_NAME_LENGTH
         */
        if (complete_len)
                return eir_append_data(ptr, ad_len, EIR_NAME_SHORT,
                                       hdev->dev_name,
                                       HCI_MAX_SHORT_NAME_LENGTH);

        return ad_len;
}

u8 eir_append_appearance(struct hci_dev *hdev, u8 *ptr, u8 ad_len)
{
        return eir_append_le16(ptr, ad_len, EIR_APPEARANCE, hdev->appearance);
}

u8 eir_append_service_data(u8 *eir, u16 eir_len, u16 uuid, u8 *data,
                           u8 data_len)
{
        eir[eir_len++] = sizeof(u8) + sizeof(uuid) + data_len;
        eir[eir_len++] = EIR_SERVICE_DATA;
        put_unaligned_le16(uuid, &eir[eir_len]);
        eir_len += sizeof(uuid);
        memcpy(&eir[eir_len], data, data_len);
        eir_len += data_len;

        return eir_len;
}

static u8 *create_uuid16_list(struct hci_dev *hdev, u8 *data, ptrdiff_t len)
{
        u8 *ptr = data, *uuids_start = NULL;
        struct bt_uuid *uuid;

        if (len < 4)
                return ptr;

        list_for_each_entry(uuid, &hdev->uuids, list) {
                u16 uuid16;

                if (uuid->size != 16)
                        continue;

                uuid16 = get_unaligned_le16(&uuid->uuid[12]);
                if (uuid16 < 0x1100)
                        continue;

                if (uuid16 == PNP_INFO_SVCLASS_ID)
                        continue;

                if (!uuids_start) {
                        uuids_start = ptr;
                        uuids_start[0] = 1;
                        uuids_start[1] = EIR_UUID16_ALL;
                        ptr += 2;
                }

                /* Stop if not enough space to put next UUID */
                if ((ptr - data) + sizeof(u16) > len) {
                        uuids_start[1] = EIR_UUID16_SOME;
                        break;
                }

                *ptr++ = (uuid16 & 0x00ff);
                *ptr++ = (uuid16 & 0xff00) >> 8;
                uuids_start[0] += sizeof(uuid16);
        }

        return ptr;
}

static u8 *create_uuid32_list(struct hci_dev *hdev, u8 *data, ptrdiff_t len)
{
        u8 *ptr = data, *uuids_start = NULL;
        struct bt_uuid *uuid;

        if (len < 6)
                return ptr;

        list_for_each_entry(uuid, &hdev->uuids, list) {
                if (uuid->size != 32)
                        continue;

                if (!uuids_start) {
                        uuids_start = ptr;
                        uuids_start[0] = 1;
                        uuids_start[1] = EIR_UUID32_ALL;
                        ptr += 2;
                }

                /* Stop if not enough space to put next UUID */
                if ((ptr - data) + sizeof(u32) > len) {
                        uuids_start[1] = EIR_UUID32_SOME;
                        break;
                }

                memcpy(ptr, &uuid->uuid[12], sizeof(u32));
                ptr += sizeof(u32);
                uuids_start[0] += sizeof(u32);
        }

        return ptr;
}

static u8 *create_uuid128_list(struct hci_dev *hdev, u8 *data, ptrdiff_t len)
{
        u8 *ptr = data, *uuids_start = NULL;
        struct bt_uuid *uuid;

        if (len < 18)
                return ptr;

        list_for_each_entry(uuid, &hdev->uuids, list) {
                if (uuid->size != 128)
                        continue;

                if (!uuids_start) {
                        uuids_start = ptr;
                        uuids_start[0] = 1;
                        uuids_start[1] = EIR_UUID128_ALL;
                        ptr += 2;
                }

                /* Stop if not enough space to put next UUID */
                if ((ptr - data) + 16 > len) {
                        uuids_start[1] = EIR_UUID128_SOME;
                        break;
                }

                memcpy(ptr, uuid->uuid, 16);
                ptr += 16;
                uuids_start[0] += 16;
        }

        return ptr;
}

void eir_create(struct hci_dev *hdev, u8 *data)
{
        u8 *ptr = data;
        size_t name_len;

        name_len = strnlen(hdev->dev_name, sizeof(hdev->dev_name));

        if (name_len > 0) {
                /* EIR Data type */
                if (name_len > 48) {
                        name_len = 48;
                        ptr[1] = EIR_NAME_SHORT;
                } else {
                        ptr[1] = EIR_NAME_COMPLETE;
                }

                /* EIR Data length */
                ptr[0] = name_len + 1;

                memcpy(ptr + 2, hdev->dev_name, name_len);

                ptr += (name_len + 2);
        }

        if (hdev->inq_tx_power != HCI_TX_POWER_INVALID) {
                ptr[0] = 2;
                ptr[1] = EIR_TX_POWER;
                ptr[2] = (u8)hdev->inq_tx_power;

                ptr += 3;
        }

        if (hdev->devid_source > 0) {
                ptr[0] = 9;
                ptr[1] = EIR_DEVICE_ID;

                put_unaligned_le16(hdev->devid_source, ptr + 2);
                put_unaligned_le16(hdev->devid_vendor, ptr + 4);
                put_unaligned_le16(hdev->devid_product, ptr + 6);
                put_unaligned_le16(hdev->devid_version, ptr + 8);

                ptr += 10;
        }

        ptr = create_uuid16_list(hdev, ptr, HCI_MAX_EIR_LENGTH - (ptr - data));
        ptr = create_uuid32_list(hdev, ptr, HCI_MAX_EIR_LENGTH - (ptr - data));
        ptr = create_uuid128_list(hdev, ptr, HCI_MAX_EIR_LENGTH - (ptr - data));
}

u8 eir_create_per_adv_data(struct hci_dev *hdev, u8 instance, u8 *ptr)
{
        struct adv_info *adv = NULL;
        u8 ad_len = 0;

        /* Return 0 when the current instance identifier is invalid. */
        if (instance) {
                adv = hci_find_adv_instance(hdev, instance);
                if (!adv)
                        return 0;
        }

        if (adv) {
                memcpy(ptr, adv->per_adv_data, adv->per_adv_data_len);
                ad_len += adv->per_adv_data_len;
                ptr += adv->per_adv_data_len;
        }

        return ad_len;
}

u8 eir_create_adv_data(struct hci_dev *hdev, u8 instance, u8 *ptr, u8 size)
{
        struct adv_info *adv = NULL;
        u8 ad_len = 0, flags = 0;
        u32 instance_flags;

        /* Return 0 when the current instance identifier is invalid. */
        if (instance) {
                adv = hci_find_adv_instance(hdev, instance);
                if (!adv)
                        return 0;
        }

        instance_flags = hci_adv_instance_flags(hdev, instance);

        /* If instance already has the flags set skip adding it once
         * again.
         */
        if (adv && eir_get_data(adv->adv_data, adv->adv_data_len, EIR_FLAGS,
                                NULL))
                goto skip_flags;

        /* The Add Advertising command allows userspace to set both the general
         * and limited discoverable flags.
         */
        if (instance_flags & MGMT_ADV_FLAG_DISCOV)
                flags |= LE_AD_GENERAL;

        if (instance_flags & MGMT_ADV_FLAG_LIMITED_DISCOV)
                flags |= LE_AD_LIMITED;

        if (!hci_dev_test_flag(hdev, HCI_BREDR_ENABLED))
                flags |= LE_AD_NO_BREDR;

        if (flags || (instance_flags & MGMT_ADV_FLAG_MANAGED_FLAGS)) {
                /* If a discovery flag wasn't provided, simply use the global
                 * settings.
                 */
                if (!flags)
                        flags |= mgmt_get_adv_discov_flags(hdev);

                /* If flags would still be empty, then there is no need to
                 * include the "Flags" AD field".
                 */
                if (flags && (ad_len + eir_precalc_len(1) <= size)) {
                        ptr[0] = 0x02;
                        ptr[1] = EIR_FLAGS;
                        ptr[2] = flags;

                        ad_len += 3;
                        ptr += 3;
                }
        }

skip_flags:
        if (adv) {
                memcpy(ptr, adv->adv_data, adv->adv_data_len);
                ad_len += adv->adv_data_len;
                ptr += adv->adv_data_len;
        }

        if (instance_flags & MGMT_ADV_FLAG_TX_POWER) {
                s8 adv_tx_power;

                if (ext_adv_capable(hdev)) {
                        if (adv)
                                adv_tx_power = adv->tx_power;
                        else
                                adv_tx_power = hdev->adv_tx_power;
                } else {
                        adv_tx_power = hdev->adv_tx_power;
                }

                /* Provide Tx Power only if we can provide a valid value for it */
                if (adv_tx_power != HCI_TX_POWER_INVALID &&
                    (ad_len + eir_precalc_len(1) <= size)) {
                        ptr[0] = 0x02;
                        ptr[1] = EIR_TX_POWER;
                        ptr[2] = (u8)adv_tx_power;

                        ad_len += 3;
                        ptr += 3;
                }
        }

        return ad_len;
}

static u8 create_default_scan_rsp(struct hci_dev *hdev, u8 *ptr)
{
        u8 scan_rsp_len = 0;

        if (hdev->appearance)
                scan_rsp_len = eir_append_appearance(hdev, ptr, scan_rsp_len);

        return eir_append_local_name(hdev, ptr, scan_rsp_len);
}

u8 eir_create_scan_rsp(struct hci_dev *hdev, u8 instance, u8 *ptr)
{
        struct adv_info *adv;
        u8 scan_rsp_len = 0;

        if (!instance)
                return create_default_scan_rsp(hdev, ptr);

        adv = hci_find_adv_instance(hdev, instance);
        if (!adv)
                return 0;

        if ((adv->flags & MGMT_ADV_FLAG_APPEARANCE) && hdev->appearance)
                scan_rsp_len = eir_append_appearance(hdev, ptr, scan_rsp_len);

        memcpy(&ptr[scan_rsp_len], adv->scan_rsp_data, adv->scan_rsp_len);

        scan_rsp_len += adv->scan_rsp_len;

        if (adv->flags & MGMT_ADV_FLAG_LOCAL_NAME)
                scan_rsp_len = eir_append_local_name(hdev, ptr, scan_rsp_len);

        return scan_rsp_len;
}

void *eir_get_service_data(u8 *eir, size_t eir_len, u16 uuid, size_t *len)
{
        size_t dlen;

        while ((eir = eir_get_data(eir, eir_len, EIR_SERVICE_DATA, &dlen))) {
                u16 value = get_unaligned_le16(eir);

                if (uuid == value) {
                        if (len)
                                *len = dlen - 2;
                        return &eir[2];
                }

                eir += dlen;
                eir_len -= dlen;
        }

        return NULL;
}