Connection refused implementing a tcp server - c

Question

I'm trying to make a server and client. But when I try to connect the client to the server, I get connection refused. The other answers on stack overflow said to make sure you have listen() and accept(), which I do, and to check the firewalls. So I turned off all the firewalls just to make sure.
I still get connection refused, so I tried ./telnet 10.1.10.13 9696, and got:
Trying 10.1.10.13...
telnet: connect to address 10.1.10.13: Connection refused
telnet: Unable to connect to remote host
Here's the code for the server
int setUpServer(struct fuzzerObj *ptr)
{
/* Declarations */
int hostSocket, yes = 1, rtrn;
union
{
struct sockaddr_in in;
}address;
/* Create Socket */
hostSocket = socket(AF_INET, SOCK_STREAM, 0);
if(hostSocket < 0)
{
errorHandler("Could not create socket\n", FUNCTION_ID_SET_UP_SERVER);
return -1;
}
/* Reuse Address */
rtrn = setsockopt(hostSocket, SOL_SOCKET, SO_REUSEADDR, &yes, sizeof(yes));
if(rtrn < 0)
{
errorHandler("Couldn't Reuse Address\n", FUNCTION_ID_SET_UP_SERVER);
return -1;
}
errno = 0;
/* Set Up Struct */
address.in.sin_len = sizeof(address.in);
address.in.sin_family = AF_INET;
address.in.sin_port = BBPORT_NUMBER;
address.in.sin_addr.s_addr = htonl(INADDR_ANY);
memset(address.in.sin_zero, 0, sizeof(address.in.sin_zero));
/* Bind Address to Socket */
rtrn = bind(hostSocket, (struct sockaddr*) &address, address.in.sin_len);
if(rtrn < 0)
{
errorHandler("Can't Bind Address to Socket\n", FUNCTION_ID_SET_UP_SERVER);
perror("");
return -1;
}
/* listen */
rtrn = listen(hostSocket, ptr->numberOfClients);
if(rtrn < 0)
{
errorHandler("Can't Listen\n", FUNCTION_ID_SET_UP_SERVER);
return -1;
}
while(1) acceptClient(hostSocket);
return 0;
}
int acceptClient(int fd)
{
struct sockaddr_storage addr;
socklen_t addr_len = sizeof(addr);
int clientFd = accept(fd, (struct sockaddr *) &addr, &addr_len);
if(clientFd < 0)
{
printf("Can't Accept Client\n");
return -1;
}
return clientFd;
}
and the code for the client:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <netinet/in.h>
#include <stdbool.h>
#include <sys/types.h>
#include <unistd.h>
#include <errno.h>
#define BLACKBOX_PORT 9696
int main(int argc, char *argv[])
{
/* Check To See If an argument was passed */
if(argc < 2)
{
printf("No enough Arguments\n");
return -1;
}
/* Declaration's */
const char *ip = argv[1];
int sockfd, fd, rtrn;
char *inBuf;
struct sockaddr_in servaddr,cliaddr;
socklen_t len = sizeof(cliaddr);
/* Get Socket to Connect to Fuzz Server */
sockfd = socket(PF_INET, SOCK_STREAM, 0);
if(sockfd < 0)
{
perror("Can't Create Socket");
return -1;
}
/* Fill Out Struct */
servaddr.sin_family = AF_INET;
servaddr.sin_port = htons(BLACKBOX_PORT);
inet_pton(AF_INET, ip, &servaddr.sin_addr);
/* Attempt Connection */
fd = connect(sockfd,(struct sockaddr *)&servaddr, sizeof(servaddr));
if(fd < 0)
{
perror("Can not connect to BlackBox Fuzz server");
return -1;
}
/* Allocate Space in Memory for Incoming Connection */
inBuf = (char *) malloc(1025);
if(inBuf == NULL)
{
perror("Mem Error");
return -1;
}
/* Read From Socket */
rtrn = read(fd, inBuf, 1024);
if(rtrn < 0)
{
perror("Can't Read Data From BlackBox Server");
return -1;
}
printf("Received Data: %s\n", inBuf);
free(inBuf);
return 0;
}
Output from client:
./client 10.1.10.13
Can not connect to BlackBox Fuzz server
Connection refused
Any help would be appreciated, thanks.

Answer 1

Assuming that you're running this code on a little-endian machine, you need to use htons() when assigning the port number on the server side too.
(On big-endian machines htons() is a "no-op", but you should always use it to ensure portability)