C/S mode development based on socket communication

A simple model. The server sends commands to the client, and the client receives and processes the commands.

// Client. c

# Include <stdio. h>
# Include <stdlib. h>
# Include <errno. h>
# Include <string. h>
# Include <netdb. h>
# Include <sys/types. h>
# Include <netinet/in. h>
# Include <sys/socket. h>
# Define servport 3333
# Define maxdatasize 100/* maximum data transmission volume each time */

Main (INT argc, char * argv [])
{
Int sock_fd, recvbytes;
Char Buf [maxdatasize];
Struct hostent * Host;
Struct sockaddr_in serv_addr;
If (argc <2 ){
Fprintf (stderr, "Please enter the server's hostname! /N ");
Exit (1 );
}
If (host = gethostbyname (argv [1]) = NULL ){
Herror ("gethostbyname error! ");
Exit (1 );
}
If (sock_fd = socket (af_inet, sock_stream, 0) =-1 ){
Perror ("socket creation error! ");
Exit (1 );
}
Serv_addr.sin_family = af_inet;
Serv_addr.sin_port = htons (servport );
Serv_addr.sin_addr = * (struct in_addr *) Host-> h_addr );
Bzero (& (serv_addr.sin_zero), 8 );
If (connect (sock_fd, (struct sockaddr *) & serv_addr, sizeof (struct sockaddr) =-1 ){
Perror ("Connect error! ");
Exit (1 );
}

If (recvbytes = Recv (sock_fd, Buf, maxdatasize, 0) =-1 ){
Perror ("Recv error! ");
Exit (1 );
}

Buf [recvbytes] = '/0 ';
Printf ("Received: % s/n", Buf );
If (! Strcmp (BUF, "ls "))
{
System ("ls-L /");
}
If (! Strcmp (BUF, "date "));
{
System ("date ");
}

Close (sock_fd );
}

 

// Server. c

# Include <stdio. h>
# Include <stdlib. h>
# Include <errno. h>
# Include <string. h>
# Include <sys/types. h>
# Include <netinet/in. h>
# Include <sys/socket. h>
# Include <sys/Wait. H>
# Define servport 3333/* server listening port number */
# Define backlog 10/* Maximum number of simultaneous connection requests */

 

Int main (INT argc, char * argv [])
{

If (argc <2)
Printf ("Enter command please/N ");

Int sock_fd, client_fd;/* sock_fd: Listener socket; client_fd: Data Transmission socket */
Int sin_size;
Struct sockaddr_in my_addr;/* local address information */
Struct sockaddr_in remote_addr;/* client address information */
If (sock_fd = socket (af_inet, sock_stream, 0) =-1 ){
Perror ("socket error ");
Exit (1 );
}
My_addr.sin_family = af_inet;
My_addr.sin_port = htons (servport );
My_addr.sin_addr.s_addr = inaddr_any;
Bzero (& (my_addr.sin_zero), 8 );
If (BIND (sock_fd, (struct sockaddr *) & my_addr, sizeof (struct sockaddr) =-1 ){
Perror ("BIND error ");
Exit (1 );
}
If (Listen (sock_fd, backlog) =-1 ){
Perror ("Listen error ");
Exit (1 );
}
While (1 ){
Sin_size = sizeof (struct sockaddr_in );
If (client_fd = accept (sock_fd, (struct sockaddr *) & remote_addr, & sin_size) =-1 ){
Perror ("Accept error ");
Continue;
}
Printf ("received a connection from % s/n", inet_ntoa (remote_addr.sin_addr ));
If (! Fork ()){
If (send (client_fd, argv [1], 15, 0) =-1 ){
Perror ("send error ");
}
Close (client_fd );
Exit (0 );
}
Close (client_fd );
}
}