This is a simple echo server that I've written while learning sockets programming.
Compile the server and run it. You can connect to it using telnet like this:
telnet localhost 1337
Disconnect the client by typing "/quit" without quotes.
This is a simple echo server that I've written while learning sockets programming.
Compile the server and run it. You can connect to it using telnet like this:
telnet localhost 1337
Disconnect the client by typing "/quit" without quotes.
/* A Simple server in C */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h> /* misc. UNIX functions */
#include <sys/socket.h> /* socket definitions */
#include <sys/types.h> /* socket types */
#include <arpa/inet.h> /* inet (3) functions */
int main(int argc, char* argv[]) {
int list_s; /* listening socket */
int conn_s; /* connecting socket */
short int port = 1337; /*port number*/
char* msg = "Welcome to the simple server v 0.1\n"; /* Welcome message */
char buffer[1024] = {0};
/* set up socket address structure */
struct sockaddr_in servaddr;
memset(&servaddr, 0, sizeof(servaddr)); /* set everything to zero */
servaddr.sin_family = AF_INET;
servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
servaddr.sin_port = htons(port);
/* create the listening socket */
if((list_s = socket(AF_INET, SOCK_STREAM, 0)) == -1) {
printf("could not create socket\n");
exit(EXIT_FAILURE);
}
/* bind the listening socket to server address and listen */
if(bind(list_s, (struct sockaddr*) &servaddr, sizeof(servaddr)) < 0) {
printf("binding failed, exiting.\n");
exit(EXIT_FAILURE);
}
if(listen(list_s, 0) < 0) {
printf("error calling listen()\n");
exit(EXIT_FAILURE);
}
/* Enter an infinite loop to respond to client requests */
while(1) {
/* listen for the incoming clients */
if((conn_s = accept(list_s, NULL, NULL)) < 0) {
printf("error calling accept()\n");
exit(EXIT_FAILURE);
}
/* Send the welcome message to the client */
send(conn_s, msg, strlen(msg), 0);
/**** using goto ****
innerloop:
recv(conn_s, buffer, sizeof(buffer), 0);
if(strncmp(buffer,"/quit\r\n", strlen(buffer)) == 0) {
if(close(conn_s) < 0) {
printf("error calling close()\n");
exit(EXIT_FAILURE);
}
} else {
send(conn_s, buffer, sizeof(buffer), 0);
memset(buffer, 0, sizeof(buffer));
goto innerloop;
}
****/
do {
recv(conn_s, buffer, sizeof(buffer), 0);
} while(strncmp(buffer,"/quit\r\n", strlen(buffer)) != 0 &&
send(conn_s, buffer, sizeof(buffer), 0)&&
memset(buffer, 0, sizeof(buffer)));
if(close(conn_s) < 0) {
printf("error calling close()\n");
exit(EXIT_FAILURE);
}
}
close(list_s); /* close the listening socket */
return 0;
}
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