Linux Socket 编程实例(一个Echo程序)

来源：互联网发布：linux挂载iso镜像 yum 编辑：程序博客网时间：2024/06/05 14:50

本文编的是echo服务器示例程序，当收到客户端的数据，服务器把数据不经加工地发送给客户。采用TCP连接，采用端口8080进行设计，在整个过程中主要涉及socket的通信。

1. [代码]echo_server.c

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#include <netdb.h>
#include <sys/socket.h>
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
 
#define EHCO_PORT    8080
#define MAX_CLIENT_NUM        10
 
intmain()
{
    intsocketfd;
    socketfd = socket(AF_INET, SOCK_STREAM, 0);
        
    if(socketfd == -1)
    {
        printf("errno=%d ",errno);
        exit(1);
    }
    else
    {
        printf("socket create successfully ");
    }
 
    structsockaddr_in sa;
    bzero(&sa,sizeof(sa));
    sa.sin_family = AF_INET;
    sa.sin_port = htons(EHCO_PORT);
    sa.sin_addr.s_addr = htons(INADDR_ANY);
    bzero(&(sa.sin_zero), 8);
 
    if(bind(socketfd, (structsockaddr *)&sa, sizeof(sa))!= 0)
    {
        printf("bind failed ");
        printf("errno=%d ",errno);
        exit(1);
    }
    else
    {
        printf("bind successfully ");
    }
 
    //listen
    if(listen(socketfd ,MAX_CLIENT_NUM) != 0)
    {
        printf("listen error ");
        exit(1);
    }
    else
    {
        printf("listen successfully ");
    }
 
    intclientfd;
    structsockaddr_in clientAdd;
    charbuff[101];
    socklen_t len = sizeof(clientAdd);
    intclosing =0;
    while( closing == 0  && (clientfd = accept(socketfd, (structsockaddr *)&clientAdd, &len)) >0 )
    {
        intn;
        while((n = recv(clientfd,buff, 100,0 )) > 0)
        {
            printf("number of receive bytes = %d ", n);
            write(STDOUT_FILENO, buff, n);
            send(clientfd, buff, n, 0);
            buff[n] = '';
            if(strcmp(buff,"quit ") == 0)
            {
                break;
            }
            elseif(strcmp(buff,"close ") == 0)
            {
                //server closing
                closing = 1;
                printf("server is closing ");
                break;
            }
        }
 
        close(clientfd);
    }
 
    close(socketfd);
 
    return0;
}

2. [代码]测试方法

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linyongting@linyongting:~$ telnet 192.168.0.69 8080
Trying 192.168.0.69...
Connected to 192.168.0.69.
Escape character is '^]'.
hello! This is my first packet.Can you reply to me?
hello! This is my first packet.Can you reply to me?
Ohh, U did it!
Ohh, U did it!
see U next time!!!
see U next time!!!
quit
quit
Connection closed by foreign host.
linyongting@linyongting:~$ telnet 192.168.0.69 8080
Trying 192.168.0.69...
Connected to 192.168.0.69.
Escape character is '^]'.
close
close
Connection closed by foreign host.

3. [代码]服务器运行日志

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linyongting@linyongting:~/program/c$ ./echoServer
socket create successfully
bind successfully
listen successfully
//第一次通信
number of receive bytes = 53
hello! This is my first packet.Can you reply to me?
number of receive bytes = 16
Ohh, U did it!
number of receive bytes = 20
see U next time!!!
number of receive bytes = 6
quit
//第二次通信
number of receive bytes = 7
close
server is closing

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