[网络协议]Linux TCP server/client例程

1.服务器端

#include<stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <string.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>


#define SERVER_PORT 8080
#define MAX_SERVERS 10
int main(int argc ,char **argv)
{
    int fd_socket = 0;
    int is_bind = 0;
    int is_listen = 0;
    int fd_client = 0;
    int client_num = 0;
    int add_len = 0;
    unsigned int recv_len = 0;
    struct sockaddr_in sock_server_addr;
    socklen_t sock_len;
    unsigned char recv_buffer[100] = {'\0'};
    fd_socket = socket(AF_INET, SOCK_STREAM, 0);
    if(fd_socket == -1)
    {
        return fd_socket;
    }

    sock_server_addr.sin_family = AF_INET;
    sock_server_addr.sin_port = htons(SERVER_PORT);
    sock_server_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    memset(sock_server_addr.sin_zero, 0, 8);

    is_bind = bind(fd_socket, ( const struct sockaddr *)&sock_server_addr, \
                    sizeof(struct sockaddr));
    if(is_bind == -1)
    {
        return is_bind;
    }

    is_listen = listen(fd_socket, MAX_SERVERS);
    if (is_listen == -1)
    {
        return -1;
    }
    
    while (1)
    {
        add_len = sizeof(struct sockaddr);
        fd_client = accept(fd_socket, (struct sockaddr *)&sock_server_addr, &add_len);
        if(fd_client != -1)
        {
            client_num++;
            printf("Get connection from client %d: %s\n", client_num, inet_ntoa(sock_server_addr.sin_addr));
            if (!fork())
            {
                 while (1)
                {
                    recv_len = recv(fd_client, recv_buffer, sizeof(recv_buffer) - 1, 0);
                    if (recv_len <= 0)
                    {
                        close(fd_socket);
                        return -1;
                    }
                    else
                    {
                        recv_buffer[recv_len] = '\0';
                        printf("Got message from client %d: %s\n", client_num, recv_buffer);
                    }
                }
            }
        }

    }
    close(fd_socket);

    return 0;
}

2.客户端

#include <stdio.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <string.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>


#define SERVER_PORT 8080

int main(int argc, char **argv)
{
    int fd_socket = 0;
    int ret;
    struct sockaddr_in sock_server_addr;
    unsigned char send_buffer[100] = {'\0'};
    int send_len;

    fd_socket = socket(AF_INET, SOCK_STREAM, 0);
    if(fd_socket == -1)
    {
        printf("built socket err.\n");
        return fd_socket;
    }

    sock_server_addr.sin_family = AF_INET;
    sock_server_addr.sin_port = htons(SERVER_PORT);
    if (inet_aton("192.168.0.112", &sock_server_addr.sin_addr) == 0)
    {
        printf("invalid server_ip\n");
		return -1;
    }
    memset(sock_server_addr.sin_zero, 0, 8);
    ret = connect(fd_socket, (struct sockaddr *)&sock_server_addr, sizeof(struct sockaddr));
    if (ret == -1)
    {
        printf("connect error!\n");
		return -1;
    }
    while (1)
    {
        if (fgets(send_buffer, sizeof(send_buffer) - 1, stdin))
        {
            send_len = send(fd_socket, send_buffer, strlen(send_buffer), 0);
            if (send_len <= 0)
            {
                close(fd_socket);
                return -1;
            }
            else
            {
                printf("Sent %d bytes.\n", send_len);
            }
        }
    }

    return 0;
}