controller-legacy/handlers/discovery.c

#include <string.h>
#include <stdlib.h>
#include <stdint.h>
#include <stdio.h>
#include <uuid/uuid.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <netdb.h>
#include <errno.h>

#include <logger.h>
#include <handlers.h>
#include <helpers.h>
#include <mpack.h>
#include <enums.h>

void
handler_discovery(int fd, controller_t *controller)
{
    ssize_t bytes_transferred;
    uint16_t discovery_answer_port;
    struct sockaddr_in si_other;
    socklen_t slen = sizeof(si_other);

    if((bytes_transferred = recvfrom(fd, &discovery_answer_port, sizeof(discovery_answer_port), 0, (struct sockaddr *) &si_other, &slen)) <= 0)
    {
        LOG_ERROR("received invalid discovery from %s\n", inet_ntoa(si_other.sin_addr));
        return;
    }
    LOG_INFO("received discovery from %s:%d\n", inet_ntoa(si_other.sin_addr), discovery_answer_port);

    if(discovery_answer_port == 0)
    {
        LOG_ERROR("invalid port received\n");
        return;
    }

    char* payload;
    size_t payload_size;
    mpack_writer_t writer;
    mpack_writer_init_growable(&writer, &payload, &payload_size);

    mpack_start_map(&writer, 2);
    mpack_write_uint(&writer, DISCOVERY_MAPPING_ID);
    mpack_write_bin(&writer, (char*)controller->id, sizeof(uuid_t));
    mpack_write_uint(&writer, DISCOVERY_MAPPING_COMMAND_PORT);
    mpack_write_u16(&writer, controller->command_port);
    mpack_write_uint(&writer, DISCOVERY_MAPPING_RELAY_COUNT);
    mpack_write_u8(&writer, controller->relay_count);
    mpack_write_uint(&writer, COMMAND_MAPPING_PERIODS_COUNT);
    mpack_write_cstr(&writer, controller->name);
    mpack_finish_map(&writer);

    // finish writing
    if(mpack_writer_destroy(&writer) != mpack_ok)
    {
        LOG_ERROR("error writing discovery answer payload\n");
        return;

    }

    int fd_answer = helper_connect_tcp_server(inet_ntoa(si_other.sin_addr), discovery_answer_port);
    if(fd_answer == -1)
    {
        LOG_ERROR("error during connecting\n");
        free(payload);
        return;
    }

    if((bytes_transferred = send(fd_answer, &payload_size, sizeof(payload_size), 0)) <= 0)
    {
        LOG_ERROR("error during sending\n");
        free(payload);
        close(fd_answer);
        return;
    }
    if((bytes_transferred = send(fd_answer, payload, payload_size, 0)) <= 0)
    {
        LOG_ERROR("error during sending\n");
        free(payload);
        close(fd_answer);
        return;
    }

    free(payload);
    close(fd_answer);
}