Ethernet Communication Error
- by SivaKumar
Hi,
I wrote a program to query the status of the Ethernet printer for that i created a TCP Stream Socket and i send the query command to the printer.In case of Error less condition it returns No error status but in error case its getting hang at recv command.Even i used Non blocking now the recv command returns nothing and error set as Resource temporarily unavailable.
code:
#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <errno.h>
#include <stdlib.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/socket.h>
#include <signal.h>
#include <termios.h>
#include <poll.h>
#include <netinet/tcp.h>
#include <stdarg.h>
int main()
{
int ConnectSocket,ConnectSocket1,select_err,err,nRet,nBytesRead;
struct timeval waitTime = {10,30};
fd_set socket_set;
unsigned char * dataBuf = NULL;
unsigned char tempVar, tempVar1, tempVar2, tempVar3;
char reset[] = "\033E 2\r";
char print[] = "\033A 1\r";
char buf[1024]={0};
ConnectSocket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
printf("The Socket ID is %d\n",ConnectSocket);
if (ConnectSocket < 0)
{
perror("socket()");
return 0;
}
struct sockaddr_in clientService;
clientService.sin_family = AF_INET;
clientService.sin_addr.s_addr = inet_addr("192.168.0.129"); //Printer IP
clientService.sin_port = htons( 9100); // Printer Port
if ( connect( ConnectSocket, (struct sockaddr*) &clientService, sizeof(clientService) ) == -1) {
perror("connect()");
close(ConnectSocket);
return -1;
}
/* if((nRet = ioctl(ConnectSocket , FIONREAD, &nBytesRead) == -1))
{
perror("ioctl()");
}
perror("ioctl()");
*/
FD_ZERO(&socket_set);
FD_SET(ConnectSocket, &socket_set);
do
{
errno=0;
select_err = select(ConnectSocket+1, NULL, &socket_set, NULL, &waitTime);
}while(errno==EINPROGRESS);
if (-1 == select_err || 0 == select_err)
{
int optVal = 0;
int optLen = sizeof(optVal);
if(select_err == -1)
{
perror("select() write-side");
}
else
{
//Timeout
errno=0;
err = getsockopt(ConnectSocket,
SOL_SOCKET,
SO_ERROR,
(char*)&optVal,
&optLen);
printf("the return of the getsockopt is %d\n",err);
printf("the opt val is %s\n",(char*)optVal);
perror("getsockopt()");
if(err == -1)
{
perror("getsockopt() write-side");
}
}
printf("Select Failed during write - ConnectSocket: %d\n", ConnectSocket);
//close(ConnectSocket);
return -1;
}
err = send(ConnectSocket,print,sizeof(print)-1, 0);
printf("\n No of Bytes Send is %d\n",err);
if(err == -1 || err ==0)
{
perror("send()");
//close(ConnectSocket);
return -1;
}
FD_ZERO(&socket_set);
FD_SET(ConnectSocket, &socket_set);
do
{
errno=0;
select_err = select(ConnectSocket+1, NULL, &socket_set, NULL, &waitTime);
}while(errno==EINPROGRESS);
if (-1 == select_err || 0 == select_err)
{
printf("Select Failed during write - ConnectSocket: %d\n", ConnectSocket);
return -1;
}
err = send(ConnectSocket,reset,sizeof(reset)-1, 0);
printf("\n No of Bytes Send is %d\n",err);
if(err == -1 || err ==0)
{
perror("send()");
//close(ConnectSocket);
return -1;
}
FD_ZERO(&socket_set);
FD_SET(ConnectSocket, &socket_set);
printf("i am in reading \n");
select_err = select(ConnectSocket+1, &socket_set, NULL, NULL, &waitTime);
printf("the retun of the read side select is %d \n",select_err);
perror("select()");
if (-1 == select_err|| 0 == select_err)
{
printf("Read timeout; ConnectSocket: %d\n", ConnectSocket);
close(ConnectSocket);
perror("close()");
return -1;
}
printf("Before Recv\n");
nBytesRead = recv(ConnectSocket , buf, 1024, 0);
printf("No of Bytes read is %d\n",nBytesRead);
printf("%s\n",buf);
if(nBytesRead == -1)
{
perror("recv()");
close(ConnectSocket);
perror("clode()");
return -1;
}
close(ConnectSocket);
return 1;
}
