amo-ej1
April 21st, 2007, 10:20 AM
Here is a sample implementation of a c application which handles a TCP connection:
Basicly it llistens on all interfaces on port 6667, when somebody connects to it, it reads all the data until end of stream occurs. All the data get echo'ed to standard out and when the connection terminates the application also ends.
//
// TCP connection example, handles
// one connection.
//
// by Elie De Brauwer - 20070421
//
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <arpa/inet.h>
#define PORT 6667
#define BUFSIZE 100
int main(int argc, char **argv)
{
//
// Open socket
//
int sock = socket(PF_INET,SOCK_STREAM,0);
if(sock == -1)
{
printf("%m\n");
exit(1);
}
//
// Bind to port ander interface
//
struct sockaddr_in sa;
sa.sin_family = AF_INET;
sa.sin_port = htons(PORT);
sa.sin_addr.s_addr=htons(INADDR_ANY);
int res = bind(sock, (struct sockaddr *) &sa, sizeof(sa));
if(res != 0)
{
printf("%m\n");
close(sock);
exit(1);
}
//
// Start listening
//
res = listen(sock,0);
if(res != 0)
{
printf("%m\n");
close(sock);
exit(1);
}
//
// Accept incoming connection (TCP only)
//
struct sockaddr_in clientSa;
int size=sizeof(clientSa);
int clientSock = accept(sock,(struct sockaddr *) &clientSa, &size);
if(clientSock == -1)
{
printf("%m\n");
close(sock);
exit(1);
}
//
// Connection established
//
printf("Incoming connection from %s port %d\n", inet_ntoa(clientSa.sin_addr) , ntohs(clientSa.sin_port));
//
// Read the data
//
char data[BUFSIZE];
res = read(clientSock,data,BUFSIZE-1);
while(res > 0)
{
data[res]=0;
printf("%s\n",data);
res = read(clientSock,data,BUFSIZE-1);
}
// Close the socket
close(clientSock);
close(sock);
}