C Language network Programming-standard step (improved version) _c language

Server.c

Copy Code code as follows:

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

#define PORT 4444
#define BACKLOG 5
#define MAX_FD 256

void setnonblocking (int);

int main (int argc, char *argv[]) {
int sock_fd, NEW_FD, New_fd2, EPFD, Nfds;
struct sockaddr_in server_addr, client_addr;
int sin_size;
int nbytes;
int on = 1;
Char buffer[1024];
struct epoll_event ev, EVENTS[20];

EPFD = Epoll_create (MAX_FD);

if ((SOCK_FD = socket (af_inet, sock_stream, 0)) = = 1) {
Perror ("socket");
Exit (1);
}

SetSockOpt (SOCK_FD, Sol_socket, so_reuseaddr, &on, sizeof (on));
Setnonblocking (SOCK_FD);

EV.DATA.FD = SOCK_FD;
ev.events = Epollin | Epollet;
Epoll_ctl (EPFD, Epoll_ctl_add, SOCK_FD, &ev);

memset (&server_addr, 0, sizeof (struct sockaddr_in));
server_addr.sin_family = af_inet;
SERVER_ADDR.SIN_ADDR.S_ADDR = htonl (Inaddr_any);
Server_addr.sin_port = htons (port);

if (bind (SOCK_FD, struct sockaddr *) (&AMP;SERVER_ADDR), sizeof (struct sockaddr)) = = 1) {
Perror ("bind");
Exit (1);
}

if (Listen (SOCK_FD, BACKLOG) = = 1) {
Perror ("Listen");
Exit (1);
}

printf ("Server start ... \ n");

sin_size = sizeof (struct sockaddr_in);

int i;

while (1) {
Nfds = epoll_wait (EPFD, events, 20, 500);
for (i = 0; i < Nfds; i++) {
if (events[i].data.fd = = sock_fd) {
if ((new_fd = Accept (sock_fd, (struct sockaddr *) (&AMP;CLIENT_ADDR), &sin_size)) = = = 1) {
Perror ("accept");
Exit (1);
}
printf ("Server Get connection from%s\n", Inet_ntoa (CLIENT_ADDR.SIN_ADDR));
Setnonblocking (NEW_FD);
EV.DATA.FD = NEW_FD;
ev.events = Epollin | Epollet;
Epoll_ctl (EPFD, Epoll_ctl_add, NEW_FD, &ev);

else if (events[i].events & Epollin) {
if ((new_fd2 = EVENTS[I].DATA.FD) < 0) continue;
if ((nbytes = read (new_fd2, buffer, 1024)) = = 1) {
Perror ("read");
Exit (1);
else if (nbytes = 0) {
Close (NEW_FD2);
EVENTS[I].DATA.FD =-1;
}
printf ("Server read from%s\n", Inet_ntoa (CLIENT_ADDR.SIN_ADDR));
EV.DATA.FD = NEW_FD2;
ev.events = Epollout | Epollet;
Epoll_ctl (EPFD, Epoll_ctl_mod, NEW_FD2, &ev);

else if (events[i].events & epollout) {
NEW_FD2 = EVENTS[I].DATA.FD;
Write (New_fd2, "Server Received", 16);
EV.DATA.FD = NEW_FD2;
ev.events = Epollin | Epollet;
Epoll_ctl (EPFD, Epoll_ctl_mod, NEW_FD2, &ev);
}
}
}

return 0;
}

void setnonblocking (int fd) {
int opts;
if ((opts = Fcntl (FD, F_GETFL)) < 0) {
Perror ("Fcntl (FD, F_GETFL");
Exit (1);
}

opts = opts | O_nonblock;
if (Fcntl (FD, F_SETFL, opts) < 0) {
Perror ("Fcntl (FD, F_SETFL, opts");
Exit (1);
}
}

Client.c

Copy Code code as follows:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <netdb.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>

#define PORT 4444

int main (int argc, char *argv[]) {
int sock_fd;
struct sockaddr_in server_addr;
struct Hostent *host;
Char buffer[1024];

if (ARGC < 2) {
Perror ("Need hostname");
Exit (1);
}

if ((host = gethostbyname (argv[1])) = = NULL) {
Perror ("gethostbyname");
Exit (1);
}

if ((SOCK_FD = socket (af_inet, sock_stream, 0)) = = 1) {
Perror ("socket");
Exit (1);
}

memset (&server_addr, 0, sizeof (struct sockaddr_in));
server_addr.sin_family = af_inet;
Server_addr.sin_port = htons (port);
server_addr.sin_addr = * (struct in_addr *) host->h_addr);

If Connect (sock_fd, (struct sockaddr *) (&AMP;SERVER_ADDR), sizeof (struct sockaddr)) = = 1) {
Perror ("Connect");
Exit (1);
}

while (1) {
printf ("Please input something:\n");
Fgets (buffer, 1024, stdin);
Write (sock_fd, buffer, strlen (buffer));
Read (sock_fd, buffer, 1024);
printf ("From server:%s\n", buffer);
}
Close (SOCK_FD);

return 0;
}