测试平台：三星S4，内核3.4.5

Ubuntu版本：14.04

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1. 打开手机移动热点中USB网络共享，并将手机通过USB连接到PC

2. Ubuntu下使用命令ifconfig

2.1 inet addr:192.168.42.193就是我们客户端程序connect使用的地址：

address.sin_family = AF_INET;

address.sin_addr.s_addr = inet_addr("192.168.42.193");

address.sin_port = htons(9734);

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len = sizeof(address);

result = connect(sockfd, (struct sockaddr *)&address, len);

2.2 服务器端也是使用192.168.42.193这个ip地址进行bind，调用bind()函数之后，为socket()函数创建的套接字关联一个相应地址，发送到这个地址的数据可以通过该套接字读取与使用。

server_address.sin_family = AF_INET;

server_address.sin_addr.s_addr = inet_addr("192.168.42.193");

server_address.sin_port = htons(9734);

server_len = sizeof(server_address);

bind(server_sockfd, (struct sockaddr *)&server_address, server_len);

或者使用: server_address.sin_addr.s_addr = htonl(INADDR_ANY); 意味着可以接收本系统所安装的任何一个网卡的数据包。

3. 编写代码并编译

arm-client3.c

/*  Make the necessary includes and set up the variables.  */

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

int main()
{
    int sockfd;
    int len;
    struct sockaddr_in address;
    int result;
    char ch = 'A';

/*  Create a socket for the client.  */

    sockfd = socket(AF_INET, SOCK_STREAM, 0);

/*  Name the socket, as agreed with the server.  */

    address.sin_family = AF_INET;
    address.sin_addr.s_addr = inet_addr("192.168.42.138");
    address.sin_port = htons(9734);
    len = sizeof(address);

/*  Now connect our socket to the server's socket.  */

    result = connect(sockfd, (struct sockaddr *)&address, len);

    if(result == -1) {
        perror("oops: client3");
        exit(1);
    }

/*  We can now read/write via sockfd.  */

    write(sockfd, &ch, 1);
    read(sockfd, &ch, 1);
    printf("char from server = %c\n", ch);
    close(sockfd);
    exit(0);
}

server3.c

/*  Make the necessary includes and set up the variables.  */

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

int main()
{
    int server_sockfd, client_sockfd;
    int server_len, client_len;
    struct sockaddr_in server_address;
    struct sockaddr_in client_address;

/*  Remove any old socket and create an unnamed socket for the server.  */

    server_sockfd = socket(AF_INET, SOCK_STREAM, 0);

/*  Name the socket.  */

    server_address.sin_family = AF_INET;
  //  server_address.sin_addr.s_addr = htonl(INADDR_ANY);
    server_address.sin_addr.s_addr = inet_addr("192.168.42.193");
    server_address.sin_port = htons(9734);
    server_len = sizeof(server_address);
    bind(server_sockfd, (struct sockaddr *)&server_address, server_len);

/*  Create a connection queue and wait for clients.  */

    listen(server_sockfd, 5);
    while(1) {
        char ch;

        printf("server waiting\n");

/*  Accept a connection.  */

        client_len = sizeof(client_address);
        client_sockfd = accept(server_sockfd, 
            (struct sockaddr *)&client_address, &client_len);

/*  We can now read/write to client on client_sockfd.  */

        read(client_sockfd, &ch, 1);
        ch++;
        write(client_sockfd, &ch, 1);
        close(client_sockfd);
    }
}

服务器编译：gcc -o server3 server3.c

客户端编译：arm-none-linux-gnueabi-gcc -static -o arm-client3 arm-client3.c

4. 运行

先将arm-client3 push到手机：adb push ./arm-client3 /sdcard/

Ubuntu下： ./server3

adb shell下： ./arm-client3