How to run client-servet TCP/IP program on two different machines? - c

Question

I googled and stack-overflowed a lot but didn't find any solution. I have a simple echo client-server program in which client sends a word and the server echoes it.
This is my server.c file:
#define PORT 4444
#define MAX_CONNESSIONI 100
int main ()
{
int serverSocket, bindStatus;
struct sockaddr_in serverAddress;
int clientSocket;
struct sockaddr_in newAddress;
char buffer[1024];
pid_t child;
socklen_t addrSize;
ssize_t nread;
// Creazione della socket
serverSocket = socket(AF_INET, SOCK_STREAM, 0);
if (serverSocket == -1) {
perror("[-]Errore durante la creazione della socket\n");
exit(-1);
}
printf("[+]Echo-Server socket has been created\n");
memset(&serverAddress, '\0', sizeof(serverAddress));
// Riempimento dei campi della struct
serverAddress.sin_family = AF_INET;
serverAddress.sin_port = htons(PORT);
serverAddress.sin_addr.s_addr = INADDR_ANY;
// Binding della socket all'indirizzo specificato. Associa alla socket un indirizzo in modo da poter essere contattata dai client
if (bind(serverSocket, (struct sockaddr*)&serverAddress, sizeof(serverAddress)) == -1) {
perror("[-]Errore durante il binding\n");
exit(1);
}
printf("[+]Bind to port %d\n", PORT);
// Imposta la socket all'ascolto. I parametri sono il descrittore della socket e la massima lunghezza della coda di connessioni entranti
if (listen(serverSocket, MAX_CONNESSIONI) != -1) {
printf("Listening . . .\n\n");
}
else {
perror("[-]Error during listening\n");
exit(1);
}
while (1) {
// Accettazione della connessione
clientSocket = accept(serverSocket, (struct sockaddr*)&newAddress, &addrSize);
if (clientSocket == -1) {
exit(-1);
}
printf("%s:%d joined\n", inet_ntoa(newAddress.sin_addr), ntohs(newAddress.sin_port));
child = fork();
if (child == 0) {
close(serverSocket);
while (1) {
// Ricezione del messaggio
if ( (nread=recv(clientSocket, buffer, sizeof buffer - 1, 0)) <= 0) {
perror("[-]Error in receiving data from server\n");
}
else {
buffer[nread] = '\0';
}
if (strcmp(buffer, ":exit") == 0) {
printf("%s:%d left\n", inet_ntoa(newAddress.sin_addr), ntohs(newAddress.sin_port));
break;
}
else {
printf("%s:%d wrote: %s\n", inet_ntoa(newAddress.sin_addr), ntohs(newAddress.sin_port), buffer);
// Invio del messaggio
send(clientSocket, buffer, strlen(buffer), 0);
bzero(buffer, sizeof(buffer));
}
}
}
}
close(clientSocket);
return 0;
}
you can compile it using
gcc -o server.out server.c
and execute it using
./server.out
and this is my client.c file:
#define PORT 4444
int main ()
{
int clientSocket;
struct sockaddr_in serverAddress;
char buffer[1024];
ssize_t nread;
// Creazione della socket
clientSocket = socket(AF_INET, SOCK_STREAM, 0);
if (clientSocket == -1) {
perror("[-]Errore durante la creazione della socket\n");
exit(-1);
}
printf("[+]Client socket has been created\n");
memset(&serverAddress, '\0', sizeof(serverAddress));
// Riempimento dei campi della struct
serverAddress.sin_family = AF_INET;
serverAddress.sin_port = htons(PORT);
serverAddress.sin_addr.s_addr = INADDR_ANY;
// Connessione
if (connect(clientSocket, (struct sockaddr*)&serverAddress, sizeof(serverAddress)) == -1) {
perror("Errore con la connessione\n");
exit(-1);
}
printf("[+]Connected to Server\n");
printf("[+]Use single-word and :exit to logout\n");
while (1) {
printf("> ");
//fgets(buffer, 1024, stdin); Per ottenere una stringa con gli spazi
fflush(stdin);
scanf("%s", buffer);
// Invio dei dati al server
if (send(clientSocket, buffer, strlen(buffer), 0) == -1) {
perror("Errore con l'invio");
exit(1);
}
// Per uscire dalla connessione
if(strcmp(buffer, ":exit") == 0) {
close(clientSocket);
printf("[-]Disconnected from Server\n");
exit(0);
}
// Riceve i dati dal server
if ( (nread=recv(clientSocket, buffer, sizeof buffer - 1, 0)) <= 0) {
perror("[-]Error in receiving data from server\n");
}
else {
buffer[nread] = '\0';
printf("Server received: %s\n", buffer);
}
}
close(clientSocket);
return 0;
}
you can compile it using gcc -o client.out client.c
and execute it using ./client.out
This works fine.
How can I edit so that I can execute the server on two different computers?

Answer 1

Change INADDR_ANY to your server IP address.
serverAddress.sin_addr.s_addr = inet_addr("192.168.1.20");