transport_tcp.c

Go to the documentation of this file.

/*
 * This file is part of the libjaylink project.
 *
 * Copyright (C) 2015-2017 Marc Schink <jaylink-dev@marcschink.de>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

#include <stdlib.h>
#include <stdint.h>
#include <string.h>
#include <sys/types.h>

#ifdef _WIN32
#include <winsock2.h>
#include <ws2tcpip.h>
#else
#include <sys/time.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netdb.h>
#include <netinet/in.h>
#endif

#include "libjaylink.h"
#include "libjaylink-internal.h"

#define CMD_SERVER      0x00
#define CMD_CLIENT      0x07

#define RESP_MAX_CONNECTIONS    0xfe

#define BUFFER_SIZE 2048

#define RECV_TIMEOUT    5000

#define SEND_TIMEOUT    5000

#define PORT_STRING "19020"

#define SERVER_HELLO_SIZE   4

#define SERVER_NAME_MAX_LENGTH  256

static int initialize_handle(struct jaylink_device_handle *devh)
{
    struct jaylink_context *ctx;

    ctx = devh->dev->ctx;

    devh->buffer_size = BUFFER_SIZE;
    devh->buffer = malloc(devh->buffer_size);

    if (!devh->buffer) {
        log_err(ctx, "Transport buffer malloc failed.");
        return JAYLINK_ERR_MALLOC;
    }

    devh->read_length = 0;
    devh->bytes_available = 0;
    devh->read_pos = 0;

    devh->write_length = 0;
    devh->write_pos = 0;

    return JAYLINK_OK;
}

static void cleanup_handle(struct jaylink_device_handle *devh)
{
    free(devh->buffer);
}

static int _recv(struct jaylink_device_handle *devh, uint8_t *buffer,
        size_t length)
{
    struct jaylink_context *ctx;
    size_t tmp;

    ctx = devh->dev->ctx;

    while (length > 0) {
        tmp = length;

        if (!socket_recv(devh->sock, buffer, &tmp, 0)) {
            log_err(ctx, "Failed to receive data from device.");
            return JAYLINK_ERR_IO;
        } else if (!tmp) {
            log_err(ctx, "Failed to receive data from device: "
                "remote connection closed.");
            return JAYLINK_ERR_IO;
        }

        buffer += tmp;
        length -= tmp;

        log_dbgio(ctx, "Received %zu bytes from device.", tmp);
    }

    return JAYLINK_OK;
}

static int handle_server_hello(struct jaylink_device_handle *devh)
{
    int ret;
    struct jaylink_context *ctx;
    uint8_t buf[SERVER_HELLO_SIZE];
    char name[SERVER_NAME_MAX_LENGTH];
    uint16_t proto_version;
    size_t length;

    ctx = devh->dev->ctx;

    ret = _recv(devh, buf, sizeof(buf));

    if (ret != JAYLINK_OK) {
        log_err(ctx, "Failed to receive hello message.");
        return ret;
    }

    if (buf[0] == RESP_MAX_CONNECTIONS) {
        log_err(ctx, "Maximum number of connections reached.");
        return JAYLINK_ERR;
    }

    if (buf[0] != CMD_SERVER) {
        log_err(ctx, "Invalid hello message received.");
        return JAYLINK_ERR_PROTO;
    }

    proto_version = buffer_get_u16(buf, 1);

    log_dbg(ctx, "Protocol version: 0x%04x.", proto_version);

    length = buf[3];
    ret = _recv(devh, (uint8_t *)name, length);

    if (ret != JAYLINK_OK) {
        log_err(ctx, "Failed to receive server name.");
        return ret;
    }

    name[length] = '\0';

    log_dbg(ctx, "Server name: %s.", name);

    return JAYLINK_OK;
}

static int set_socket_timeouts(struct jaylink_device_handle *devh)
{
    struct jaylink_context *ctx;

    ctx = devh->dev->ctx;
#ifdef _WIN32
    DWORD timeout;

    timeout = RECV_TIMEOUT;

    if (!socket_set_option(devh->sock, SOL_SOCKET, SO_RCVTIMEO, &timeout,
            sizeof(timeout))) {
        log_err(ctx, "Failed to set socket receive timeout.");
        return JAYLINK_ERR;
    }

    timeout = SEND_TIMEOUT;

    if (!socket_set_option(devh->sock, SOL_SOCKET, SO_SNDTIMEO, &timeout,
            sizeof(timeout))) {
        log_err(ctx, "Failed to set socket send timeout.");
        return JAYLINK_ERR;
    }
#else
    struct timeval timeout;

    timeout.tv_sec = RECV_TIMEOUT / 1000;
    timeout.tv_usec = (RECV_TIMEOUT % 1000) * 1000;

    if (!socket_set_option(devh->sock, SOL_SOCKET, SO_RCVTIMEO, &timeout,
            sizeof(struct timeval))) {
        log_err(ctx, "Failed to set socket receive timeout.");
        return JAYLINK_ERR;
    }

    timeout.tv_sec = SEND_TIMEOUT / 1000;
    timeout.tv_usec = (SEND_TIMEOUT % 1000) * 1000;

    if (!socket_set_option(devh->sock, SOL_SOCKET, SO_SNDTIMEO, &timeout,
            sizeof(struct timeval))) {
        log_err(ctx, "Failed to set socket send timeout.");
        return JAYLINK_ERR;
    }
#endif
    return JAYLINK_OK;
}

JAYLINK_PRIV int transport_tcp_open(struct jaylink_device_handle *devh)
{
    int ret;
    struct jaylink_context *ctx;
    struct jaylink_device *dev;
    struct addrinfo hints;
    struct addrinfo *info;
    int sock;

    dev = devh->dev;
    ctx = dev->ctx;

    log_dbg(ctx, "Trying to open device (IPv4 address = %s).",
        dev->ipv4_address);

    ret = initialize_handle(devh);

    if (ret != JAYLINK_OK) {
        log_err(ctx, "Initialize device handle failed.");
        return ret;
    }

    memset(&hints, 0, sizeof(struct addrinfo));
    hints.ai_family = AF_INET;
    hints.ai_socktype = SOCK_STREAM;
    hints.ai_protocol = IPPROTO_TCP;

    ret = getaddrinfo(dev->ipv4_address, PORT_STRING, &hints, &info);

    if (ret != 0) {
        log_err(ctx, "Address lookup failed.");
        cleanup_handle(devh);
        return JAYLINK_ERR;
    }

    sock = -1;

    for (struct addrinfo *rp = info; rp != NULL; rp = rp->ai_next) {
        sock = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);

        if (sock < 0)
            continue;

        if (!connect(sock, info->ai_addr, info->ai_addrlen))
            break;

        socket_close(sock);
        sock = -1;
    }

    freeaddrinfo(info);

    if (sock < 0) {
        log_err(ctx, "Failed to open device.");
        cleanup_handle(devh);
        return JAYLINK_ERR;
    }

    log_dbg(ctx, "Device opened successfully.");

    devh->sock = sock;
    ret = set_socket_timeouts(devh);

    if (ret != JAYLINK_OK) {
        socket_close(sock);
        cleanup_handle(devh);
        return ret;
    }

    ret = handle_server_hello(devh);

    if (ret != JAYLINK_OK) {
        socket_close(sock);
        cleanup_handle(devh);
        return ret;
    }

    return JAYLINK_OK;
}

JAYLINK_PRIV int transport_tcp_close(struct jaylink_device_handle *devh)
{
    struct jaylink_context *ctx;

    ctx = devh->dev->ctx;

    log_dbg(ctx, "Closing device (IPv4 address = %s).",
        devh->dev->ipv4_address);

    cleanup_handle(devh);

    log_dbg(ctx, "Device closed successfully.");

    return JAYLINK_OK;
}

JAYLINK_PRIV int transport_tcp_start_write(struct jaylink_device_handle *devh,
        size_t length, bool has_command)
{
    struct jaylink_context *ctx;

    if (!length)
        return JAYLINK_ERR_ARG;

    ctx = devh->dev->ctx;

    log_dbgio(ctx, "Starting write operation (length = %zu bytes).",
        length);

    if (devh->write_pos > 0)
        log_warn(ctx, "Last write operation left %zu bytes in the "
            "buffer.", devh->write_pos);

    if (devh->write_length > 0)
        log_warn(ctx, "Last write operation was not performed.");

    devh->write_length = length;
    devh->write_pos = 0;

    if (has_command) {
        devh->buffer[0] = CMD_CLIENT;
        devh->write_pos++;
    }

    return JAYLINK_OK;
}

JAYLINK_PRIV int transport_tcp_start_read(struct jaylink_device_handle *devh,
        size_t length)
{
    struct jaylink_context *ctx;

    if (!length)
        return JAYLINK_ERR_ARG;

    ctx = devh->dev->ctx;

    log_dbgio(ctx, "Starting read operation (length = %zu bytes).",
        length);

    if (devh->bytes_available > 0)
        log_dbg(ctx, "Last read operation left %zu bytes in the "
            "buffer.", devh->bytes_available);

    if (devh->read_length > 0)
        log_warn(ctx, "Last read operation left %zu bytes.",
            devh->read_length);

    devh->read_length = length;

    return JAYLINK_OK;
}

JAYLINK_PRIV int transport_tcp_start_write_read(
        struct jaylink_device_handle *devh, size_t write_length,
        size_t read_length, bool has_command)
{
    struct jaylink_context *ctx;

    if (!read_length || !write_length)
        return JAYLINK_ERR_ARG;

    ctx = devh->dev->ctx;

    log_dbgio(ctx, "Starting write / read operation (length = "
        "%zu / %zu bytes).", write_length, read_length);

    if (devh->write_pos > 0)
        log_warn(ctx, "Last write operation left %zu bytes in the "
            "buffer.", devh->write_pos);

    if (devh->write_length > 0)
        log_warn(ctx, "Last write operation was not performed.");

    if (devh->bytes_available > 0)
        log_warn(ctx, "Last read operation left %zu bytes in the "
            "buffer.", devh->bytes_available);

    if (devh->read_length > 0)
        log_warn(ctx, "Last read operation left %zu bytes.",
            devh->read_length);

    devh->write_length = write_length;
    devh->write_pos = 0;

    if (has_command) {
        devh->buffer[0] = CMD_CLIENT;
        devh->write_pos++;
    }

    devh->read_length = read_length;
    devh->bytes_available = 0;
    devh->read_pos = 0;

    return JAYLINK_OK;
}

static int _send(struct jaylink_device_handle *devh, const uint8_t *buffer,
        size_t length)
{
    struct jaylink_context *ctx;
    size_t tmp;

    ctx = devh->dev->ctx;

    while (length > 0) {
        tmp = length;

        if (!socket_send(devh->sock, buffer, &tmp, 0)) {
            log_err(ctx, "Failed to send data to device.");
            return JAYLINK_ERR_IO;
        }

        buffer += tmp;
        length -= tmp;

        log_dbgio(ctx, "Sent %zu bytes to device.", tmp);
    }

    return JAYLINK_OK;
}

static bool adjust_buffer(struct jaylink_device_handle *devh, size_t size)
{
    struct jaylink_context *ctx;
    uint8_t *buffer;
    size_t num;

    ctx = devh->dev->ctx;

    /* Adjust buffer size to a multiple of BUFFER_SIZE bytes. */
    num = size / BUFFER_SIZE;

    if (size % BUFFER_SIZE > 0)
        num++;

    size = num * BUFFER_SIZE;
    buffer = realloc(devh->buffer, size);

    if (!buffer) {
        log_err(ctx, "Failed to adjust buffer size to %zu bytes.",
            size);
        return false;
    }

    devh->buffer = buffer;
    devh->buffer_size = size;

    log_dbg(ctx, "Adjusted buffer size to %zu bytes.", size);

    return true;
}

JAYLINK_PRIV int transport_tcp_write(struct jaylink_device_handle *devh,
        const uint8_t *buffer, size_t length)
{
    int ret;
    struct jaylink_context *ctx;
    size_t tmp;

    ctx = devh->dev->ctx;

    if (length > devh->write_length) {
        log_err(ctx, "Requested to write %zu bytes but only %zu bytes "
            "are expected for the write operation.", length,
            devh->write_length);
        return JAYLINK_ERR_ARG;
    }

    /*
     * Store data in the buffer if the expected number of bytes for the
     * write operation is not reached.
     */
    if (length < devh->write_length) {
        if (devh->write_pos + length > devh->buffer_size) {
            if (!adjust_buffer(devh, devh->write_pos + length))
                return JAYLINK_ERR_MALLOC;
        }

        memcpy(devh->buffer + devh->write_pos, buffer, length);

        devh->write_length -= length;
        devh->write_pos += length;

        log_dbgio(ctx, "Wrote %zu bytes into buffer.", length);
        return JAYLINK_OK;
    }

    /*
     * Expected number of bytes for this write operation is reached and
     * therefore the write operation will be performed.
     */
    devh->write_length = 0;

    /* Send data directly to the device if the buffer is empty. */
    if (!devh->write_pos)
        return _send(devh, buffer, length);

    tmp = MIN(length, devh->buffer_size - devh->write_pos);

    /*
     * Fill up the internal buffer in order to reduce the number of
     * messages sent to the device for performance reasons.
     */
    memcpy(devh->buffer + devh->write_pos, buffer, tmp);

    length -= tmp;
    buffer += tmp;

    log_dbgio(ctx, "Buffer filled up with %zu bytes.", tmp);

    ret = _send(devh, devh->buffer, devh->write_pos + tmp);

    devh->write_pos = 0;

    if (ret != JAYLINK_OK)
        return ret;

    if (!length)
        return JAYLINK_OK;

    return _send(devh, buffer, length);
}

JAYLINK_PRIV int transport_tcp_read(struct jaylink_device_handle *devh,
        uint8_t *buffer, size_t length)
{
    int ret;
    struct jaylink_context *ctx;

    ctx = devh->dev->ctx;

    if (length > devh->read_length) {
        log_err(ctx, "Requested to read %zu bytes but only %zu bytes "
            "are expected for the read operation.", length,
            devh->read_length);
        return JAYLINK_ERR_ARG;
    }

    if (length <= devh->bytes_available) {
        memcpy(buffer, devh->buffer + devh->read_pos, length);

        devh->read_length -= length;
        devh->bytes_available -= length;
        devh->read_pos += length;

        log_dbgio(ctx, "Read %zu bytes from buffer.", length);
        return JAYLINK_OK;
    }

    if (devh->bytes_available) {
        memcpy(buffer, devh->buffer + devh->read_pos,
            devh->bytes_available);

        buffer += devh->bytes_available;
        length -= devh->bytes_available;
        devh->read_length -= devh->bytes_available;

        log_dbgio(ctx, "Read %zu bytes from buffer to flush it.",
            devh->bytes_available);

        devh->bytes_available = 0;
        devh->read_pos = 0;
    }

    ret = _recv(devh, buffer, length);

    if (ret != JAYLINK_OK)
        return ret;

    devh->read_length -= length;

    return JAYLINK_OK;
}