/*
 * rpc_server_loopback.c
 * ---------------------
 * Remote procedure call transport over loopback socket.
 *
 * Copyright (c) 2016, NORDUnet A/S All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 * - Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 *
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 *
 * - Neither the name of the NORDUnet nor the names of its contributors may
 *   be used to endorse or promote products derived from this software
 *   without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>	/* close */

#include "hal.h"
#include "hal_internal.h"

static int fd;

hal_error_t hal_rpc_server_transport_init(void)
{
    struct sockaddr_in sin;

    fd = socket(AF_INET, SOCK_DGRAM, 0);
    if (fd == -1)
	return perror("socket"), HAL_ERROR_RPC_TRANSPORT;
    sin.sin_family = AF_INET;
    sin.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
    sin.sin_port = 17425;
    if (bind(fd, (const struct sockaddr *)&sin, sizeof(sin)) != 0)
	return perror("bind"), HAL_ERROR_RPC_TRANSPORT;
    return HAL_OK;
}

hal_error_t hal_rpc_server_transport_close(void)
{
    if (close(fd) != 0)
	return perror("close"), HAL_ERROR_RPC_TRANSPORT;
    return HAL_OK;
}

hal_error_t hal_rpc_sendto(const uint8_t * const buf, const size_t len, void *opaque)
{
    struct sockaddr_in *sin = (struct sockaddr_in *)opaque;
    int ret;

    if ((ret = sendto(fd, buf, len, 0, (struct sockaddr *)sin, sizeof(*sin))) == -1)
	return perror("sendto"), HAL_ERROR_RPC_TRANSPORT;
    return HAL_OK;
}

hal_error_t hal_rpc_recvfrom(uint8_t * const buf, size_t * const len, void **opaque)
{
    static struct sockaddr_in sin;
    socklen_t sin_len = sizeof(sin);
    int ret;

    if ((ret = recvfrom(fd, buf, *len, 0, (struct sockaddr *)&sin, &sin_len)) == -1)
	return HAL_ERROR_RPC_TRANSPORT;
    *opaque = (void *)&sin;
    *len = ret;
    return HAL_OK;
}