FL2440 通过Socket使开发板作为服务器支持多个客户端连接并与之通信，可通过命令获取当前温度。

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主机操作系统：Centos 6.5
交叉编译器环境：arm-linux-gcc-4.5.4
开发板平台： FL2440        
Linux内核版本： 3.0
作者：songyong<[email protected]>

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RT3070无线上网卡

Ds18b20温度传感器

实现功能：开发板通过无线上网卡连入路由器，并以开发板为服务器，接收当前VLAN局域网内请求连接的多个客户端，并与之进行通信

Server服务器端：

/*********************************************************************************
 *      Copyright:  (C) 2015 songyong<handy_skyoutlook.com>
 *                  All rights reserved.
 *
 *       Filename:  inet_server.c
 *    Description:  This file 
 *                 
 *        Version:  1.0.0(2015年09月18日)
 *         Author:  sky <[email protected]>
 *      ChangeLog:  1, Release initial version on "2015年09月18日 22时32分02秒"
 *                 
 ********************************************************************************/
#include <stdio.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>
#include <error.h>
#include <errno.h>
#include <pthread.h>


#define LEN 1024
#define LE  124
#define DEFAULT_PORT 2222 
#define CONVERT 0.0625
#define TWO 2

void *chat(void *arg);
/********************************************************************************
 *  Description:
 *   Input Args:
 *  Output Args:
 * Return Value:
 ********************************************************************************/
int main (int argc, char **argv)
{
    int     socket_fd,connect_fd;
    struct  sockaddr_in servaddr;
    char    data_buf[LEN];
    int     n;
    int     flag = 1,len = sizeof(int);
    pthread_t tid;

    if( (socket_fd = socket(AF_INET, SOCK_STREAM,0)) == -1)
    {
        printf("create socket error: %s(errno: %d)\n",strerror(errno),errno);
        exit(0);
    }

    if(setsockopt(socket_fd, SOL_SOCKET, SO_REUSEADDR, &flag,len))
    {
        perror("setsockopt");
        exit(1);
    }
    memset(&servaddr,0,sizeof(LEN));
    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(DEFAULT_PORT);
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);

    if( bind(socket_fd,(struct sockaddr *)&servaddr, sizeof(servaddr)) == -1)
    {
        printf("bind socket error: %s(errno: %d)\n",strerror(errno),errno);
        exit(0);
    }

    if( listen(socket_fd,10) == -1)
    {
        printf("listen socket error: %s(errno: %d)\n",strerror(errno),errno);
        exit(0);
    }

    printf("Please waiting for client's request.....\n");

    while(1)
    {
        struct sockaddr_in client_addr;
        socklen_t length = sizeof(client_addr);

        if( (connect_fd = accept(socket_fd, (struct sockaddr *)(&client_addr), &length)) < 0)
        {
            printf("accept socket error: %s(errno: %d)",strerror(errno),errno);
               exit(0);
        }
        if(0 != pthread_create(&tid, NULL, chat, (void *)&connect_fd) )
       {
                printf("pthread create fail!\n");
                return -1;
       }
    }
    close(socket_fd);
    return 0;
} /* ----- End of main() ----- */



void *chat(void *arg)
{
    char    recv_buf[LEN];
    char    send_buf[LEN];
    int     choice_fd;
    int               ret;
    int     connect_fd =  *((int *)arg);

    int     temp_fd;
    int     data =0;
    unsigned char result[TWO];
    float   temperature = 0;
    char    tem_buf[LE];
#if 0
    struct timeval tv;
    tv.tv_sec = 0;
    tv.tv_usec =700;
#endif
    printf("ADD NEW Client%d !\n",connect_fd);

while(1)
{
    fd_set server_fd_set; 
    FD_ZERO(&server_fd_set);
    FD_SET(STDIN_FILENO,&server_fd_set);
    FD_SET(connect_fd,&server_fd_set);

    ret = select(connect_fd+1,&server_fd_set,NULL,NULL, NULL);

    if(ret == 0)
    {
       printf("time out.\n");
       return 0;
    }
    if(ret < 0)
    {
       printf("select error\n");
       return 0;
    }

    if(FD_ISSET(connect_fd, &server_fd_set))
    {
        if(recv(connect_fd, recv_buf, sizeof(recv_buf),0) < 0)
        {
            printf("recv fail\n");
            return 0;
        }

        if(strcmp("close",recv_buf) == 0)
            exit(0);

        else if(strcmp("TT",recv_buf) == 0)
        {
            if((temp_fd = open("/dev/ds18b20",O_RDWR|O_NONBLOCK)) < 0)
            {
                perror("open ds18b20 device fail.\n");
                return NULL;
            }

            if(2 != read(temp_fd, result, sizeof(result)) )
            {
                printf("read temperature wrong!!\n");
            }

            data = (int)result[1];
            data <<=8;
            data |= result[0]; 
            temperature = data * CONVERT;
            printf("Temperature:%.2f\n",temperature);
            sprintf(tem_buf,"Temperature:%.2f℃",temperature);
            write(connect_fd,tem_buf,sizeof(tem_buf));
        }
        else{
        printf("recv msg from client%d:\n",connect_fd);
        printf("%s\n",recv_buf);
        }
    }

    if(FD_ISSET(STDIN_FILENO,&server_fd_set))
    {
       printf("You will send msg to client:\n");
       fflush(stdin);
       scanf("%s",send_buf);
       printf("%s\n",send_buf);

       if(strcmp(send_buf,"close") == 0)
           exit(0);

       printf("爹，您想发信息给哪个儿子？\n");
       scanf("%d",&choice_fd);
       write(choice_fd,send_buf,sizeof(send_buf)); 
    }
}
    //close(connect_fd);
}

Client客户端：

/*********************************************************************************
 *      Copyright:  (C) 2015 songyong<handy_skyoutlook.com>
 *                  All rights reserved.
 *
 *       Filename:  inet_sclient.c
 *    Description:  This file 
 *                 
 *        Version:  1.0.0(2015年09月29日)
 *         Author:  sky <[email protected]>
 *      ChangeLog:  1, Release initial version on "2015年09月29日 14时53分19秒"
 *                 
 ********************************************************************************/
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <pthread.h>
#include <netinet/in.h>
#include <string.h>
#include <error.h>
#include <errno.h>

#define DEFAULLT_PORT 2222 
#define LEN 1024 
void *chat(void *arg);
/********************************************************************************
 *  Description:
 *   Input Args:
 *  Output Args:
 * Return Value:
 ********************************************************************************/
int main (int argc, char **argv)
{
    struct sockaddr_in clientaddr;
    int    sockfd;

    if(argc != 2)
    {
        printf("Usage: ./client <ipaddress>\n");
        exit(0);
    }

    if( (sockfd = socket(AF_INET, SOCK_STREAM,0)) < 0)
    {
        printf("create socket error:%s(errno: %d)\n",strerror(errno),errno);
        exit(0);
    }

    memset(&clientaddr,0,sizeof(clientaddr));
    clientaddr.sin_family = AF_INET;
    clientaddr.sin_port = htons(DEFAULLT_PORT);

    if(inet_pton(AF_INET, argv[1], &clientaddr.sin_addr) <= 0)
    {
        printf("inet_pton error for %s\n",argv[1]);
        exit(0);
    }

    if(connect(sockfd, (struct sockaddr *)&clientaddr, sizeof(clientaddr)) < 0)
    {
        printf("error:%s(errno:%d)\n",strerror(errno),errno);
       //printf("connect to %s fail!\n",argv[1]);
        exit(0);
    }

    pthread_t tid;

    if( (pthread_create(&tid, NULL, chat, (void *)&sockfd)) != 0) 
    {
        printf("error:%s(errno:%d)\n",strerror(errno),errno);
        exit(0);
    }
       printf("now con\n");

    while(1);

    close(sockfd);
    return 0;
} /* ----- End of main() ----- */

void *chat(void *arg)
{
    char recv_buf[LEN];
    char send_buf[LEN];
    int ret;
    int sockfd = *((int *)arg);

    struct timeval tv;
    tv.tv_sec = 0;
    tv.tv_usec = 600;

while(1)
{
    fd_set client_set_fd;

    FD_ZERO(&client_set_fd);
    FD_SET(STDIN_FILENO, &client_set_fd);
    FD_SET(sockfd, &client_set_fd);
    ret = select(sockfd+1,&client_set_fd, NULL, NULL, NULL);

    if(ret == 0)
    {
        printf("time out!\n");
        exit(0);
    }
    if(ret < 0)
    {
        printf("select failed\n");
        exit(0);
    }

    if(FD_ISSET(sockfd, &client_set_fd))
    {
    if(recv(sockfd, recv_buf, sizeof(recv_buf),0) >0)
    {
        printf("recv msg from Server:\n");
        printf("%s\n",recv_buf);
        if(strcmp(recv_buf,"quit") == 0)
            exit(0);
    }

    }

    if(FD_ISSET(STDIN_FILENO,&client_set_fd))
    {
        printf("You will send msg to Server:\n");
        fflush(stdin);
        scanf("%s",send_buf);
        printf("%s\n",send_buf);

        if( strcmp(send_buf,"quit") == 0)
            exit(0);

        write(sockfd,send_buf,sizeof(send_buf));
    }
}

}

server服务器端：

client端：

套套命令可获取服务器端当前温度。

close可以在客户端让服务器断开。quit可以关闭客户端。实现端口复用，但是还没有使用心跳包检测机制。很简陋，图形界面也没有美化，不过程序实现了功能这些都是虚的。10月份找到工作以后再来修复和记录文档吧。偏头痛，睡觉去。。。