listener.c

基于ARM9嵌入式开发板LINUX环境下的程序代码-linux udp

/*
****************************************Copyright (c)**************************************************
**                               Guangzhou Zhiyuan Electronic Co.,LTD.
**                                     graduate school
**                                 http://www.zyinside.com
**
**------------------------------------- File Info ------------------------------------------------------
** File name:           listener.c
** Last modified Date:  2005-12-30
** Last Version:        1.0
** Descriptions:        listener of UDP.
**------------------------------------------------------------------------------------------------------
** Created by:          Ganda
** Created date:        2005-12-27
** Version:             1.0
** Descriptions:        Preliminary version.
**
**------------------------------------------------------------------------------------------------------
** Modified by:		Chenxibing
** Modified date:	2005-12-30	
** Version:		1.0.1
** Descriptions:	modified for MagicARM2410.
**
********************************************************************************************************
*/

#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <sys/types.h>
#include <netinet/in.h>
#include <sys/wait.h>
#include <sys/socket.h>
                                  
#define PORT 5000                      // The port which is communicate with server
#define BACKLOG 10
#define LENGTH  512                    // Buffer length     
                                                                            
int main ()
{   int sockfd;                        // Socket file descriptor
    int nsockfd;                       // New Socket file descriptor
    int num;
    int sin_size;                      // to store struct size
    char revbuf[LENGTH];               // Send buffer
    struct sockaddr_in addr_local;     
    struct sockaddr_in addr_remote;    

               
    /* Get the Socket file descriptor */  
    if( (sockfd = socket(AF_INET, SOCK_DGRAM, 0)) == -1 )  
    {   
        printf ("ERROR: Failed to obtain Socket Despcritor.\n");
        return (0);
    }
    else
    {
        printf ("OK: Obtain Socket Despcritor sucessfully.\n");
    }
    
    /* Fill the local socket address struct */
    addr_local.sin_family = AF_INET;           // Protocol Family
    addr_local.sin_port = htons(PORT);         // Port number
    addr_local.sin_addr.s_addr  = INADDR_ANY;  // AutoFill local address
    bzero(&(addr_local.sin_zero), 8);          // Flush the rest of struct

    /*  Blind a special Port */
    if( bind(sockfd, (struct sockaddr*)&addr_local, sizeof(struct sockaddr)) == -1 )
    {  
    	  printf ("ERROR: Failed to bind Port %d.\n",PORT);
        return (0);
    }
    else
    {
        printf("OK: Bind the Port %d sucessfully.\n",PORT);
    }
   
    sin_size = sizeof(struct sockaddr);
   
    if(num = recvfrom(sockfd, revbuf, LENGTH, 0, (struct sockaddr *)&addr_remote, &sin_size) == -1) 
    {
        printf("ERROR!\n");
    }  
    else
    {
        printf("OK: %s.\n",revbuf);
    }
    close(sockfd);  
    return (0);
}