/* SPDX-License-Identifier: GPL-3.0-or-later

 * Copyright © 2016-2020 The TokTok team.

 * Copyright © 2015 Tox project.

 */

#include "group_onion_announce.h"

#include <assert.h>

#include <string.h>

#include "DHT.h"

#include "attributes.h"

#include "ccompat.h"

#include "crypto_core.h"

#include "group_announce.h"

#include "logger.h"

#include "mem.h"

#include "mono_time.h"

#include "network.h"

#include "onion_announce.h"

#include "timed_auth.h"

static_assert(TIMED_AUTH_SIZE <= ONION_ANNOUNCE_REQUEST_MAX_SIZE,

              "Timed auth does not fit into the onion packet");

static_assert(PACKED_NODE_SIZE_IP6 <= GCA_ANNOUNCE_MAX_SIZE,

              "IP6 does not fit into the GC_Announce");

static_assert(GCA_ANNOUNCE_MAX_SIZE <= ONION_MAX_EXTRA_DATA_SIZE,

              "GC_Announce does not fit into the onion packet extra data");

/**

 * GCA responses are larger than ONION_ANNOUNCE_RESPONSE_MAX_SIZE because they

 * include both the full packed-node list AND the GCA announce list.

 * handle_announce_request_common must therefore allocate its output buffer

 * dynamically (sized from the actual plaintext length), never from the old

 * constant.

 */

static_assert(GCA_ANNOUNCE_RESPONSE_MAX_SIZE > ONION_ANNOUNCE_RESPONSE_MAX_SIZE,

              "GCA_ANNOUNCE_RESPONSE_MAX_SIZE must exceed ONION_ANNOUNCE_RESPONSE_MAX_SIZE; data[] in handle_announce_request_common must be dynamically sized");

static pack_extra_data_cb pack_group_announces;

static int pack_group_announces(void *object, const Logger *logger, const Memory *mem, const Mono_Time *mono_time, uint8_t num_nodes,

                                uint8_t *plain, uint16_t plain_size, uint8_t *response, uint16_t response_size, uint16_t offset)

{

    GC_Announces_List *gc_announces_list = (GC_Announces_List *)object;

    GC_Public_Announce public_announce;

    if (gca_unpack_public_announce(logger, plain, plain_size,

                                   &public_announce) == -1) {

        LOGGER_WARNING(logger, "Failed to unpack public group announce");

        return -1;

    }

    const GC_Peer_Announce *new_announce = gca_add_announce(mem, mono_time, gc_announces_list, &public_announce);

    if (new_announce == nullptr) {

        LOGGER_ERROR(logger, "Failed to add group announce");

        return -1;

    }

    GC_Announce gc_announces[GCA_MAX_SENT_ANNOUNCES];

    const int num_ann = gca_get_announces(gc_announces_list,

                                          gc_announces,

                                          GCA_MAX_SENT_ANNOUNCES,

                                          public_announce.chat_public_key,

                                          new_announce->base_announce.peer_public_key);

    if (num_ann < 0) {

        LOGGER_ERROR(logger, "failed to get group announce");

        return -1;

    }

    assert(num_ann <= UINT8_MAX);

    size_t announces_length = 0;

    if (gca_pack_announces_list(logger, response + offset, response_size - offset, gc_announces, (uint8_t)num_ann,

                                &announces_length) != num_ann) {

        LOGGER_WARNING(logger, "Failed to pack group announces list");

        return -1;

    }

    return announces_length;

}

void gca_onion_init(GC_Announces_List *group_announce, Onion_Announce *onion_a)

{

    onion_announce_extra_data_callback(onion_a, GCA_MAX_SENT_ANNOUNCES * GCA_ANNOUNCE_MAX_SIZE, pack_group_announces,

                                       group_announce);

}

int create_gca_announce_request(

    const Memory *mem, const Random *rng, uint8_t *packet, uint16_t max_packet_length, const uint8_t *dest_client_id,

    const uint8_t *public_key, const uint8_t *secret_key, const uint8_t *ping_id,

    const uint8_t *client_id, const uint8_t *data_public_key, uint64_t sendback_data,

    const uint8_t *gc_data, uint16_t gc_data_length)

{

    if (max_packet_length < ONION_ANNOUNCE_REQUEST_MAX_SIZE || gc_data_length == 0) {

        return -1;

    }

    uint8_t plain[ONION_PING_ID_SIZE + CRYPTO_PUBLIC_KEY_SIZE + CRYPTO_PUBLIC_KEY_SIZE +

                                     ONION_ANNOUNCE_SENDBACK_DATA_LENGTH + GCA_PUBLIC_ANNOUNCE_MAX_SIZE];

    uint8_t *position_in_plain = plain;

    const size_t encrypted_size = sizeof(plain) - GCA_PUBLIC_ANNOUNCE_MAX_SIZE + gc_data_length;

    memcpy(plain, ping_id, ONION_PING_ID_SIZE);

    position_in_plain += ONION_PING_ID_SIZE;

    memcpy(position_in_plain, client_id, CRYPTO_PUBLIC_KEY_SIZE);

    position_in_plain += CRYPTO_PUBLIC_KEY_SIZE;

    memcpy(position_in_plain, data_public_key, CRYPTO_PUBLIC_KEY_SIZE);

    position_in_plain += CRYPTO_PUBLIC_KEY_SIZE;

    memcpy(position_in_plain, &sendback_data, sizeof(sendback_data));

    position_in_plain += sizeof(sendback_data);

    memcpy(position_in_plain, gc_data, gc_data_length);

    packet[0] = NET_PACKET_ANNOUNCE_REQUEST;

    random_nonce(rng, packet + 1);

    memcpy(packet + 1 + CRYPTO_NONCE_SIZE, public_key, CRYPTO_PUBLIC_KEY_SIZE);

    const int len = encrypt_data(mem, dest_client_id, secret_key, packet + 1, plain,

                                 encrypted_size, packet + 1 + CRYPTO_NONCE_SIZE + CRYPTO_PUBLIC_KEY_SIZE);

    const uint32_t full_length = (uint32_t)len + 1 + CRYPTO_NONCE_SIZE + CRYPTO_PUBLIC_KEY_SIZE;

    if (full_length != ONION_ANNOUNCE_REQUEST_MIN_SIZE + gc_data_length) {

        return -1;

    }

    return full_length;

}