import of www.freescada.com/public-dist/libmbus-0.7.0.tar.gz
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195
mbus/mbus-tcp.c
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195
mbus/mbus-tcp.c
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//------------------------------------------------------------------------------
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// Copyright (C) 2011, Robert Johansson, Raditex AB
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// All rights reserved.
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//
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// FreeSCADA
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// http://www.FreeSCADA.com
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// freescada@freescada.com
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//
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//------------------------------------------------------------------------------
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#include <unistd.h>
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#include <fcntl.h>
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#include <sys/socket.h>
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#include <sys/types.h>
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#include <arpa/inet.h>
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#include <netinet/in.h>
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#include <netdb.h>
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#include <stdio.h>
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#include <strings.h>
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#include <mbus/mbus.h>
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#include <mbus/mbus-tcp.h>
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#define PACKET_BUFF_SIZE 2048
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//------------------------------------------------------------------------------
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/// Setup a TCP/IP handle.
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//------------------------------------------------------------------------------
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mbus_tcp_handle *
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mbus_tcp_connect(char *host, int port)
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{
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mbus_tcp_handle *handle;
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struct hostent *host_addr;
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struct sockaddr_in s;
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struct timeval time_out;
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if (host == NULL)
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{
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return NULL;
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}
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if ((handle = (mbus_tcp_handle *)malloc(sizeof(mbus_tcp_handle))) == NULL)
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{
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char error_str[128];
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snprintf(error_str, sizeof(error_str), "%s: failed to allocate memory for handle\n", __PRETTY_FUNCTION__);
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mbus_error_str_set(error_str);
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return NULL;
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}
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handle->host = host; // strdup ?
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handle->port = port;
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//
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// create the TCP connection
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//
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if ((handle->sock = socket(AF_INET,SOCK_STREAM, 0)) < 0)
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{
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char error_str[128];
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snprintf(error_str, sizeof(error_str), "%s: failed to setup a socket.", __PRETTY_FUNCTION__);
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mbus_error_str_set(error_str);
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return NULL;
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}
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s.sin_family = AF_INET;
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s.sin_port = htons(port);
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/* resolve hostname */
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if ((host_addr = gethostbyname(host)) == NULL)
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{
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char error_str[128];
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snprintf(error_str, sizeof(error_str), "%s: unknown host: %s", __PRETTY_FUNCTION__, host);
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mbus_error_str_set(error_str);
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free(handle);
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return NULL;
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}
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bcopy((void *)(host_addr->h_addr), (void *)(&s.sin_addr), host_addr->h_length);
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if (connect(handle->sock, (struct sockaddr *)&s, sizeof(s)) < 0)
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{
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char error_str[128];
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snprintf(error_str, sizeof(error_str), "%s: Failed to establish connection to %s:%d", __PRETTY_FUNCTION__, host, port);
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mbus_error_str_set(error_str);
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free(handle);
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return NULL;
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}
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// Set a timeout
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time_out.tv_sec = 2; //seconds
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time_out.tv_usec = 0;
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setsockopt(handle->sock, SOL_SOCKET, SO_SNDTIMEO, &time_out, sizeof(time_out));
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setsockopt(handle->sock, SOL_SOCKET, SO_RCVTIMEO, &time_out, sizeof(time_out));
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return handle;
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}
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//------------------------------------------------------------------------------
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//
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//------------------------------------------------------------------------------
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int
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mbus_tcp_disconnect(mbus_tcp_handle *handle)
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{
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if (handle == NULL)
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{
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return -1;
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}
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close(handle->sock);
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free(handle);
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return 0;
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}
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//------------------------------------------------------------------------------
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//
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//------------------------------------------------------------------------------
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int
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mbus_tcp_send_frame(mbus_tcp_handle *handle, mbus_frame *frame)
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{
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u_char buff[PACKET_BUFF_SIZE];
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int len, ret;
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if (handle == NULL || frame == NULL)
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{
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return -1;
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}
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if ((len = mbus_frame_pack(frame, buff, sizeof(buff))) == -1)
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{
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char error_str[128];
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snprintf(error_str, sizeof(error_str), "%s: mbus_frame_pack failed\n", __PRETTY_FUNCTION__);
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mbus_error_str_set(error_str);
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return -1;
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}
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if ((ret = write(handle->sock, buff, len)) != len)
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{
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char error_str[128];
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snprintf(error_str, sizeof(error_str), "%s: Failed to write frame to socket (ret = %d)\n", __PRETTY_FUNCTION__, ret);
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mbus_error_str_set(error_str);
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return -1;
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}
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return 0;
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}
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//------------------------------------------------------------------------------
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//
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//------------------------------------------------------------------------------
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int
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mbus_tcp_recv_frame(mbus_tcp_handle *handle, mbus_frame *frame)
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{
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char buff[PACKET_BUFF_SIZE];
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int len, remaining, nread;
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bzero((void *)buff, sizeof(buff));
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//
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// read data until a packet is received
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//
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remaining = 1; // start by reading 1 byte
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len = 0;
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do {
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//printf("%s: Attempt to read %d bytes [len = %d]", __PRETTY_FUNCTION__, remaining, len);
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if ((nread = read(handle->sock, &buff[len], remaining)) == -1)
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{
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mbus_error_str_set("M-Bus tcp transport layer failed to read data.");
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//fprintf(stderr, "%s: aborting recv frame (remaining = %d, len = %d, nread = %d)",
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// __PRETTY_FUNCTION__, remaining, len, nread);
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return -1;
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}
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//printf("%s: Got %d byte [remaining %d, len %d]", __PRETTY_FUNCTION__, nread, remaining, len);
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len += nread;
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} while ((remaining = mbus_parse(frame, buff, len)) > 0);
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if (remaining < 0)
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{
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mbus_error_str_set("M-Bus layer failed to parse data.");
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return -2;
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}
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return 0;
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}
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