linux下socket通信，server和client简单例子

<span style="font-family: Arial, Helvetica, sans-serif;">server.c</span>

 ==================================================================== #include <netinet/in.h>    // for sockaddr_in#include <sys/types.h>    // for socket#include <sys/socket.h>    // for socket#include <stdio.h>        // for printf#include <stdlib.h>        // for exit#include <string.h>        // for bzero/*#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>#include <unistd.h>*/#define HELLO_WORLD_SERVER_PORT    6666 #define LENGTH_OF_LISTEN_QUEUE 20#define BUFFER_SIZE 1024#define FILE_NAME_MAX_SIZE 512 int main(int argc, char **argv){    //设置一个socket地址结构server_addr,代表服务器internet地址, 端口    struct sockaddr_in server_addr;    bzero(&server_addr,sizeof(server_addr)); //把一段内存区的内容全部设置为0    server_addr.sin_family = AF_INET;    server_addr.sin_addr.s_addr = htons(INADDR_ANY);    server_addr.sin_port = htons(HELLO_WORLD_SERVER_PORT);     //创建用于internet的流协议(TCP)socket,用server_socket代表服务器socket    int server_socket = socket(PF_INET,SOCK_STREAM,0);    if( server_socket < 0)    {        printf("Create Socket Failed!");        exit(1);    }{    int opt =1;   setsockopt(server_socket,SOL_SOCKET,SO_REUSEADDR,&opt,sizeof(opt));}         //把socket和socket地址结构联系起来    if( bind(server_socket,(struct sockaddr*)&server_addr,sizeof(server_addr)))    {        printf("Server Bind Port : %d Failed!", HELLO_WORLD_SERVER_PORT);         exit(1);    }     //server_socket用于监听    if ( listen(server_socket, LENGTH_OF_LISTEN_QUEUE) )    {        printf("Server Listen Failed!");         exit(1);    }    while (1) //服务器端要一直运行    {        //定义客户端的socket地址结构client_addr        struct sockaddr_in client_addr;        socklen_t length = sizeof(client_addr);         //接受一个到server_socket代表的socket的一个连接        //如果没有连接请求,就等待到有连接请求--这是accept函数的特性        //accept函数返回一个新的socket,这个socket(new_server_socket)用于同连接到的客户的通信        //new_server_socket代表了服务器和客户端之间的一个通信通道        //accept函数把连接到的客户端信息填写到客户端的socket地址结构client_addr中        int new_server_socket = accept(server_socket,(struct sockaddr*)&client_addr,&length);        if ( new_server_socket < 0)        {            printf("Server Accept Failed!\n");            break;        }                 char buffer[BUFFER_SIZE];        bzero(buffer, BUFFER_SIZE);        length = recv(new_server_socket,buffer,BUFFER_SIZE,0);        if (length < 0)        {            printf("Server Recieve Data Failed!\n");            break;        }        char file_name[FILE_NAME_MAX_SIZE+1];        bzero(file_name, FILE_NAME_MAX_SIZE+1);        strncpy(file_name, buffer, strlen(buffer)>FILE_NAME_MAX_SIZE?FILE_NAME_MAX_SIZE:strlen(buffer));//        int fp = open(file_name, O_RDONLY);//        if( fp < 0 )        printf("%s\n",file_name);        FILE * fp = fopen(file_name,"r");        if(NULL == fp )        {            printf("File:\t%s Not Found\n", file_name);        }        else        {            bzero(buffer, BUFFER_SIZE);            int file_block_length = 0;//            while( (file_block_length = read(fp,buffer,BUFFER_SIZE))>0)            while( (file_block_length = fread(buffer,sizeof(char),BUFFER_SIZE,fp))>0)            {                printf("file_block_length = %d\n",file_block_length);                //发送buffer中的字符串到new_server_socket,实际是给客户端                if(send(new_server_socket,buffer,file_block_length,0)<0)                {                    printf("Send File:\t%s Failed\n", file_name);                    break;                }                bzero(buffer, BUFFER_SIZE);            }//            close(fp);            fclose(fp);            printf("File:\t%s Transfer Finished\n",file_name);        }        //关闭与客户端的连接        close(new_server_socket);    }    //关闭监听用的socket    close(server_socket);    return 0;}

client代码

client.c #include <netinet/in.h>    // for sockaddr_in#include <sys/types.h>    // for socket#include <sys/socket.h>    // for socket#include <stdio.h>        // for printf#include <stdlib.h>        // for exit#include <string.h>        // for bzero/*#include <sys/types.h>#include <sys/stat.h>#include <fcntl.h>#include <unistd.h>*/ #define HELLO_WORLD_SERVER_PORT    6666 #define BUFFER_SIZE 1024#define FILE_NAME_MAX_SIZE 512 int main(int argc, char **argv){    if (argc != 2)    {        printf("Usage: ./%s ServerIPAddress\n",argv[0]);        exit(1);    }     //设置一个socket地址结构client_addr,代表客户机internet地址, 端口    struct sockaddr_in client_addr;    bzero(&client_addr,sizeof(client_addr)); //把一段内存区的内容全部设置为0    client_addr.sin_family = AF_INET;    //internet协议族    client_addr.sin_addr.s_addr = htons(INADDR_ANY);//INADDR_ANY表示自动获取本机地址    client_addr.sin_port = htons(0);    //0表示让系统自动分配一个空闲端口    //创建用于internet的流协议(TCP)socket,用client_socket代表客户机socket    int client_socket = socket(AF_INET,SOCK_STREAM,0);    if( client_socket < 0)    {        printf("Create Socket Failed!\n");        exit(1);    }    //把客户机的socket和客户机的socket地址结构联系起来    if( bind(client_socket,(struct sockaddr*)&client_addr,sizeof(client_addr)))    {        printf("Client Bind Port Failed!\n");         exit(1);    }     //设置一个socket地址结构server_addr,代表服务器的internet地址, 端口    struct sockaddr_in server_addr;    bzero(&server_addr,sizeof(server_addr));    server_addr.sin_family = AF_INET;    if(inet_aton(argv[1],&server_addr.sin_addr) == 0) //服务器的IP地址来自程序的参数    {        printf("Server IP Address Error!\n");        exit(1);    }    server_addr.sin_port = htons(HELLO_WORLD_SERVER_PORT);    socklen_t server_addr_length = sizeof(server_addr);    //向服务器发起连接,连接成功后client_socket代表了客户机和服务器的一个socket连接    if(connect(client_socket,(struct sockaddr*)&server_addr, server_addr_length) < 0)    {        printf("Can Not Connect To %s!\n",argv[1]);        exit(1);    }     char file_name[FILE_NAME_MAX_SIZE+1];    bzero(file_name, FILE_NAME_MAX_SIZE+1);    printf("Please Input File Name On Server:\t");    scanf("%s", file_name);         char buffer[BUFFER_SIZE];    bzero(buffer,BUFFER_SIZE);    strncpy(buffer, file_name, strlen(file_name)>BUFFER_SIZE?BUFFER_SIZE:strlen(file_name));    //向服务器发送buffer中的数据    send(client_socket,buffer,BUFFER_SIZE,0); //    int fp = open(file_name, O_WRONLY|O_CREAT);//    if( fp < 0 )    FILE * fp = fopen(file_name,"w");    if(NULL == fp )    {        printf("File:\t%s Can Not Open To Write\n", file_name);        exit(1);    }         //从服务器接收数据到buffer中    bzero(buffer,BUFFER_SIZE);    int length = 0;    while( length = recv(client_socket,buffer,BUFFER_SIZE,0))    {        if(length < 0)        {            printf("Recieve Data From Server %s Failed!\n", argv[1]);            break;        }//        int write_length = write(fp, buffer,length);        int write_length = fwrite(buffer,sizeof(char),length,fp);        if (write_length<length)        {            printf("File:\t%s Write Failed\n", file_name);            break;        }        bzero(buffer,BUFFER_SIZE);        }    printf("Recieve File:\t %s From Server[%s] Finished\n",file_name, argv[1]);         close(fp);    //关闭socket    close(client_socket);    return 0;}