C TCP Client won't connect to the server

0
votes

I'm writing a basic TCP Client that I'm trying to connect to a TCP Server that I have already made sure works. For some reason, my client won't connect to the server. It will not get past the connection attempt. Both client and server are on the same machine, I'm using 127.0.0.1 for both and port 8080. Any pointers as to why? Thanks! 

/*
Usage: tcpclient <server_ip> <server_port> <client ip> <input_file> <output_file> <size of send/receive buffer>
*/

#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <string.h>
#include <arpa/inet.h>

int main(int argc, char ** argv) {
    char* server_ip;
    char* client_ip;
    char* input_file; 
    char* output_file;
    int server_port, buffer_size;

    server_ip = argv[1];
    server_port = atoi(argv[2]);
    client_ip = argv[3];
    input_file = argv[4];
    output_file = argv[5];
    buffer_size = atoi(argv[6]);

    int sockfd = 0;
    int bitsSent = 0;
    int bitsReceived = 0;

    char sendBuffer[buffer_size];
    char recvBuffer[buffer_size];

    struct sockaddr_in serv_addr;

    memset(recvBuffer, '0', sizeof(recvBuffer));
    memset(sendBuffer, '0', sizeof(sendBuffer));
    memset((char *)&serv_addr,0,sizeof(serv_addr)); 


    /* Check command line arguments */
    if (argc != 7) {    
        exit(0);
    }

    /* Create the socket */
    if((sockfd = socket(AF_INET, SOCK_STREAM, 0))< 0)
    {
        printf("\n Error : Could not create socket \n");
        return 1;
    }

    serv_addr.sin_family = AF_INET;
    serv_addr.sin_port = htons(server_port);
    serv_addr.sin_addr.s_addr = inet_addr(server_ip);

    /* Attempt to connect to server */
    if (connect(sockfd, (struct sockaddr *)&serv_addr, sizeof(serv_addr))<0) {
        printf("Err: Couldn't connect");
        return 1;
    }   

    /* Open the input file to read */
    FILE *fp;
    fp = fopen(input_file, "r");

    if (fp == NULL) {
        perror("Error opening the file");
        return(-1);
    }

    /* Receive the data then write to sendBuffer */
    while ((bitsSent = read(sockfd, recvBuffer, buffer_size)) >0) {
        printf("Bytes received: %d\n", bitsReceived);
        fwrite(recvBuffer, 1, bitsReceived, fp);
    }

    if (bitsReceived < 0) {
        printf("Read Error");
    }

    return 0;

}
2
csocketstcpclientserver
Define"won't connect". Error message? Core dump? Computer explodes? - user207421
Sorry, I should have been more specific. It enters the if statement where I attempt to make the connection to the server: if (connect(sockfd, (struct sockaddr *)&serv_addr, sizeof(serv_addr))<0) - user1670032
So what does connect actually return? YOu should get used to the debugger - too honest for this site
So? What's the error? Get rid of the printf() and use perror(). No hope of a solution until we know what the problem is. When you get an error, print the error. You already know it failed: just printing that information is useless. Same applies after the read/write loop. - user207421
bitsSend/bitsReceived such namings are defintily missleading. - alk

2 Answers

0
votes

You're trying to connect before you create a socket. Since sockfd is zero at that point, you're trying to connect standard input.

-2
votes

I don't remember if that was relevant but instead of:

serv_addr.sin_addr.s_addr = inet_addr(server_ip);

try:

inet_aton("127.0.0.1",&server_addr.sin_addr);

And as the other reply says you forgot to create the socket:

if((sockfd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0){
    perror("Error al crear el socket");
    exit(1);
}