Клиент-сервер

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
 
#define DEFPORT 12347
 
int main(int argc, char **argv) {
int master_sock, client_sock;
struct sockaddr_in master_addr, client_addr;
unsigned short portnum = DEFPORT;
socklen_t len;
char server_reply[] = "Hello!";
 
printf("\nStarting Simple Server...\nUsage: %s [portnum]\n\n", argv[0]);
 
if (argc > 1) {
if (sscanf(argv[1], "%hd", &portnum)!=1) portnum = DEFPORT;
}
master_sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
if (master_sock < 0) {
perror("socket() failed");
exit(EXIT_FAILURE);
}
master_addr.sin_family = AF_INET;
master_addr.sin_port = htons(portnum);
master_addr.sin_addr.s_addr = htonl(INADDR_ANY);
if (bind(master_sock, (struct sockaddr*) &master_addr, sizeof(master_addr))) {
perror("bind() failed");
exit(EXIT_FAILURE);
}
if (listen(master_sock, SOMAXCONN)) {
perror("listen() failed");
exit(EXIT_FAILURE);
}
printf("Listening port %d for incoming connections...\n", portnum);
cycle:
len = sizeof(client_addr);
client_sock = accept(master_sock, (struct sockaddr*) &client_addr, &len);
if (client_sock < 0) {
perror("accept() failed");
exit(EXIT_FAILURE);
}
printf("Connected client - %s:%u\n\n",
inet_ntoa(client_addr.sin_addr),
ntohs(client_addr.sin_port));
 
write(client_sock, server_reply, sizeof(server_reply));
shutdown(client_sock, 2);
close(client_sock);
 
goto cycle;
return EXIT_SUCCESS;
}

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <netdb.h>
#include <unistd.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
 
#define DEFPORT 12347
#define BUFSIZE 128
 
int main(int argc, char **argv) {
int my_sock;
struct sockaddr_in serv_addr;
struct hostent *he;
unsigned short portnum = DEFPORT;
socklen_t len;
char server_reply[BUFSIZE];
 
printf("\nStarting Simple Client...\nUsage: %s [host [portnum]]\n\n", argv[0]);
serv_addr.sin_family = AF_INET;
serv_addr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
if (argc > 1) {
he = gethostbyname(argv[1]);
if (!he) {
herror(argv[1]);
exit(EXIT_FAILURE);
}
if (he->h_addrtype != AF_INET) {
fprintf(stderr,"\nunsupported address family %d\n", he->h_addrtype);
exit(EXIT_FAILURE);
}
 
memcpy(&serv_addr.sin_addr.s_addr, he->h_addr_list[0], he->h_length);
}
if (argc > 2) {
if (sscanf(argv[2], "%hd", &portnum) != 1) portnum = DEFPORT;
}
serv_addr.sin_port = htons(portnum);
my_sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
if (my_sock < 0) {
perror("socket() failed");
exit(EXIT_FAILURE);
}
printf("Trying to connect %s:%d...\n",
inet_ntoa(serv_addr.sin_addr),
portnum);
if (connect(my_sock, (struct sockaddr*) &serv_addr, sizeof(serv_addr))) {
perror("connect() failed");
exit(EXIT_FAILURE);
}
do {
memset(server_reply, 0, BUFSIZE);
len = read(my_sock, server_reply, BUFSIZE);
if (len < 0) {
perror("read() failed");
exit(EXIT_FAILURE);
}
write(STDOUT_FILENO, server_reply, len);
} while (len == BUFSIZE);
fflush(stdout);
shutdown(my_sock, SHUT_RDWR);
close(my_sock);
return EXIT_SUCCESS;
}