CODEWITHSUNDEEP
csocketstcpbindingserver
tr0ubl3
tr0ubl3

Reputation: 11

Programming C: getting error when binding address and port to socket

I really don't know what I did wrong. I included all the good libraries. And tested it on my VPS and local Ubuntu installation. Also I looked up other code for the same program that do work. But I keep getting the "ERROR: could not bind internet address to the socket method" message. Here is my TCP server in C code:

#include <stdio.h>
#include <strings.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <unistd.h>
#include <netinet/in.h>
#include <stdlib.h>

//Enter The Port and the Ip Address here.

#define PORT 666
#define ADRESS 0

//Enter the amount of Maximum Poeple entering the server.
#define NUMBER_OF_CONNECTIONS 8

int main(){
    int sockfd, newsockfd, portno = 666, clilen;
    char message[1024];
    struct sockaddr_in serv_addr, cli_addr;
    int n;

    sockfd = (AF_INET, SOCK_STREAM, 0);

    if (sockfd < 0){
        printf("ERROR: could not create server-socket.\n");
        exit(1);
    }

    bzero((char *) &serv_addr, sizeof(serv_addr));

    // Declaring the port.
    //portno = 666;
    // Declaring the type of connection. (internet connection)
    serv_addr.sin_family =  AF_INET;
    // Declaring the IP.
    serv_addr.sin_addr.s_addr = INADDR_ANY;
    // Declaring the Port.
    serv_addr.sin_port = htons(portno);

    // Binding the Socket?
    if (bind(sockfd, (struct sockaddr *) &serv_addr, sizeof(serv_addr)) < 0){
        printf("ERROR: could not bind internet address to the socket method.\n");
        exit(1);
    }

    // Entering "Listen Mode".
    listen(sockfd, NUMBER_OF_CONNECTIONS);
    clilen = sizeof(cli_addr);

    // Creating a New Socket for the client.
    newsockfd = accept(sockfd, (struct sockaddr *) &cli_addr, &clilen);

    if (newsockfd < 0){
        printf("ERROR: could not accept connection.\n");
        exit(1);
    }

    //Clearing the message-buffer.
    bzero(message,1024);

    // Reading the message.
    n = read(newsockfd,message,1023);

    if (n < 0){
        printf("ERROR: could not read message.\n");
    }

    printf("Message: %s\n",message);

    n = write(newsockfd, "I got your message.", 18);

    if (n < 0)
    {
        printf("ERROR: sending to client.\n");
    }
    return 0;
}

Upvotes: 0

Views: 1126

Answers (3)

tr0ubl3
tr0ubl3

Reputation: 11

This helped me:

Ofcourse changing the sockfd = (AF_INET, SOCK_STREAM, 0); to sockfd = socket(AF_INET, SOCK_STREAM, 0); and for some reason I had to use root privileges for a port under 1024.

Can someone maybe explain why?

Thank you for the help all :D

Upvotes: 0

Ctx
Ctx

Reputation: 18420

The problem is this line:

 sockfd = (AF_INET, SOCK_STREAM, 0);

It is valid and the expression on the right side evaluates to 0 (see comma-operator in C).

Now the call to bind() is placed on fd 0, which is usually a (pseudo-)terminal. This cannot succeed.

The solution is:

 sockfd = socket(AF_INET, SOCK_STREAM, 0);

Upvotes: 4

Mikel F
Mikel F

Reputation: 3656

Try replacing:

sockfd = (AF_INET, SOCK_STREAM, 0);

with

sockfd = socket(AF_INET, SOCK_STREAM, 0);

Upvotes: 3

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