libmbus/mbus/mbus-tcp.c
2012-05-20 03:05:26 +02:00

217 lines
5.4 KiB
C

//------------------------------------------------------------------------------
// Copyright (C) 2011, Robert Johansson, Raditex AB
// All rights reserved.
//
// rSCADA
// http://www.rSCADA.se
// info@rscada.se
//
//------------------------------------------------------------------------------
#include <unistd.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <netdb.h>
#include <stdio.h>
#include <string.h>
#include <strings.h>
#include <mbus/mbus.h>
#include <mbus/mbus-tcp.h>
#define PACKET_BUFF_SIZE 2048
//------------------------------------------------------------------------------
/// Setup a TCP/IP handle.
//------------------------------------------------------------------------------
mbus_tcp_handle *
mbus_tcp_connect(char *host, int port)
{
mbus_tcp_handle *handle;
struct hostent *host_addr;
struct sockaddr_in s;
struct timeval time_out;
if (host == NULL)
{
return NULL;
}
if ((handle = (mbus_tcp_handle *)malloc(sizeof(mbus_tcp_handle))) == NULL)
{
char error_str[128];
snprintf(error_str, sizeof(error_str), "%s: failed to allocate memory for handle\n", __PRETTY_FUNCTION__);
mbus_error_str_set(error_str);
return NULL;
}
handle->host = host; // strdup ?
handle->port = port;
//
// create the TCP connection
//
if ((handle->sock = socket(AF_INET,SOCK_STREAM, 0)) < 0)
{
char error_str[128];
snprintf(error_str, sizeof(error_str), "%s: failed to setup a socket.", __PRETTY_FUNCTION__);
mbus_error_str_set(error_str);
return NULL;
}
s.sin_family = AF_INET;
s.sin_port = htons(port);
/* resolve hostname */
if ((host_addr = gethostbyname(host)) == NULL)
{
char error_str[128];
snprintf(error_str, sizeof(error_str), "%s: unknown host: %s", __PRETTY_FUNCTION__, host);
mbus_error_str_set(error_str);
free(handle);
return NULL;
}
memcpy((void *)(&s.sin_addr), (void *)(host_addr->h_addr), host_addr->h_length);
if (connect(handle->sock, (struct sockaddr *)&s, sizeof(s)) < 0)
{
char error_str[128];
snprintf(error_str, sizeof(error_str), "%s: Failed to establish connection to %s:%d", __PRETTY_FUNCTION__, host, port);
mbus_error_str_set(error_str);
free(handle);
return NULL;
}
// Set a timeout
time_out.tv_sec = 4; //seconds
time_out.tv_usec = 0;
setsockopt(handle->sock, SOL_SOCKET, SO_SNDTIMEO, &time_out, sizeof(time_out));
setsockopt(handle->sock, SOL_SOCKET, SO_RCVTIMEO, &time_out, sizeof(time_out));
return handle;
}
//------------------------------------------------------------------------------
//
//------------------------------------------------------------------------------
int
mbus_tcp_disconnect(mbus_tcp_handle *handle)
{
if (handle == NULL)
{
return -1;
}
close(handle->sock);
free(handle);
return 0;
}
//------------------------------------------------------------------------------
//
//------------------------------------------------------------------------------
int
mbus_tcp_send_frame(mbus_tcp_handle *handle, mbus_frame *frame)
{
u_char buff[PACKET_BUFF_SIZE];
int len, ret;
if (handle == NULL || frame == NULL)
{
return -1;
}
if ((len = mbus_frame_pack(frame, buff, sizeof(buff))) == -1)
{
char error_str[128];
snprintf(error_str, sizeof(error_str), "%s: mbus_frame_pack failed\n", __PRETTY_FUNCTION__);
mbus_error_str_set(error_str);
return -1;
}
if ((ret = write(handle->sock, buff, len)) == len)
{
//
// call the send event function, if the callback function is registered
//
if (_mbus_send_event)
_mbus_send_event(MBUS_HANDLE_TYPE_TCP, buff, len);
}
else
{
char error_str[128];
snprintf(error_str, sizeof(error_str), "%s: Failed to write frame to socket (ret = %d)\n", __PRETTY_FUNCTION__, ret);
mbus_error_str_set(error_str);
return -1;
}
return 0;
}
//------------------------------------------------------------------------------
//
//------------------------------------------------------------------------------
int
mbus_tcp_recv_frame(mbus_tcp_handle *handle, mbus_frame *frame)
{
char buff[PACKET_BUFF_SIZE];
int len, remaining, nread;
if (handle == NULL || frame == NULL)
{
fprintf(stderr, "%s: Invalid parameter.\n", __PRETTY_FUNCTION__);
return -1;
}
memset((void *)buff, 0, sizeof(buff));
//
// read data until a packet is received
//
remaining = 1; // start by reading 1 byte
len = 0;
do {
if ((nread = read(handle->sock, &buff[len], remaining)) == -1)
{
mbus_error_str_set("M-Bus tcp transport layer failed to read data.");
return -1;
}
len += nread;
} while ((remaining = mbus_parse(frame, buff, len)) > 0);
if (len == 0)
{
// No data received
return -1;
}
//
// call the receive event function, if the callback function is registered
//
if (_mbus_recv_event)
_mbus_recv_event(MBUS_HANDLE_TYPE_TCP, buff, len);
if (remaining < 0)
{
mbus_error_str_set("M-Bus layer failed to parse data.");
return -2;
}
return 0;
}