new to unix sockets

hey everybody!

i am experimenting with unix sockets and having some fun. i thought it would be good if i joined these forums to ask some questions....

so my first code sample is this...

Code:

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#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <netdb.h>
#include <netinet/in.h>
#include <arpa/inet.h>

int main(int argc, char *argv[])
{
        struct hostent *h;
        if (argc != 3)
        {
                fprintf(stderr, "Usage: tel [HOST] [IP]\n");
                exit(1);
        }
        h = gethostbyname(argv[1]);
        if (h == NULL)
        {
                herror("gethostbyname");
                exit(1);
        }
        char *ip =  inet_ntoa(*((struct in_addr *)h->h_addr));
        int port = *argv[2];
        printf("IP : %s\n", ip);
        printf("Port: %d\n",  port);
        int sockfd;
        struct sockaddr_in dest_addr;
        sockfd = socket(AF_INET, SOCK_STREAM, 0);
        dest_addr.sin_family = AF_INET;
        dest_addr.sin_port = htons(port);
        dest_addr.sin_addr.s_addr = inet_addr( ip);
        connect(sockfd, (struct sockaddr *)&dest_addr, sizeof(struct sockaddr));
        return 0;
}

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now i know your are all laffing at how ugly and poorly coded this is but keep in mind that i aint that advanced. it keeps printf()'ing me that i am connecting on port 56 or 55 or whatever it is it's not argv[2]. any ideas? also you can see i am trying to create a telnet typeof utility so if you could maybe direct me as what to do that'd be great. thx guys

oh and btw i use linux with g++ to compile and it compiles fine.

Well, the problem is here:

Code:

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int port = *argv[2];

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because port is an integer but argv[2] is actually a string.
Use atoi():

Code:

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int port = atoi(argv[2]);

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Oh, BTW, the usage error, I'd change `IP' to `Port' ;)

yeah thanx man that did it...

now how much / kinda what would i have to add after connect to make this work like telnet would. recv() ing or something more complex....thxf

Read the telnet RFC - telnet expects some sort of control characters, I don't really know.

But basically, to read and recv data you'd use the following calls on a stream connected socket:

recv(2) - to receive data
send(2) - to send data

Code:

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    while(1) {
      recv(fd,buf,sizeof(buf),0);
      puts(buf);
      fgets(stdin,buf,sizeof(buf));
      send(fd,buf,strlen(buf),0);
    }

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this isn't the greatest way obviously, but just an example.