메시지를 주고받는 프로그램을 코딩했는데 recvfrom 함수 문제인지 메시지를 받지 못하고 있어요..

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
 
#define PORT 10501
#define BUFFSIZE 30
#define SEND_COUND 1000;
 
void error_handling(char *message);
 
struct message_packet
{
	long packetCnt;
	char messageStr[];
};
 
int main(int argc, char **argv)
{
	FILE* file;
	struct sockaddr_in server_addr;
	struct sockaddr_in client_addr;
	int server_socket;
	int client_socket;
 
        struct message_packet meg;
	int iSockOpt;
 
	server_socket = socket( PF_INET, SOCK_DGRAM, 0 );
	if( server_socket == -1 ) error_handling( "UDP Socket ERROR!");
 
	memset( &server_addr, 0, sizeof(server_socket) );
	server_addr.sin_family = AF_INET;	
	server_addr.sin_addr.s_addr = inet_addr( "192.168.0.2" ); 
	server_addr.sin_port = htons( PORT );
 
	//prevent bind error
	iSockOpt = 1;
	setsockopt(client_socket, SOL_SOCKET, SO_REUSEADDR, &iSockOpt, sizeof(iSockOpt));
 
	if( bind( server_socket, (struct sockaddr*)&server_addr, sizeof(server_addr) ) == -1 )
		error_handling( "Bind ERROR!!" );
 
	meg.packetCnt = 0;
	sprintf(meg.messageStr, "Hello world");
 
	file = fopen( "fir_send.txt", "w");
 
	while(1)
	{
		if( meg.packetCnt >= 10 ) break;
		meg.packetCnt++;	
 
		sendto( server_socket, (char*)&meg, sizeof(meg), 0, (struct sockaddr*)&server_addr, sizeof(server_addr) );
 
		fprintf( file, "[#%2d] %s\n", meg.packetCnt, meg.messageStr );
	}
 
	fclose(file);
	close(server_socket);	
 
	return 0;
}
 
void error_handling(char *message)
{
        fputs(message, stderr);
        fputc('\n', stderr);
        exit(1);
}

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <sys/types.h>
#include <sys/socket.h>
 
#define BUFFSIZE 1020
#define PORT 10502
 
void error_handling(char *message);
 
struct message_packet
{
	long packetCnt;
	char message[BUFFSIZE];
};
 
int main(int argc, char **argv)
{
	FILE* file;
	struct sockaddr_in server_addr;
	struct sockaddr_in client_addr;
	int server_socket;
	int client_socket;
 
	struct message_packet meg;
	int str_len;
	int client_size;
	int iSockOpt;
 
	client_socket = socket( PF_INET, SOCK_DGRAM, 0);
	if( client_socket == -1) error_handling("UDP Socket ERROR!");
 
	memset( &client_addr, 0, sizeof(client_socket) );
	client_addr.sin_family = AF_INET;		
	client_addr.sin_addr.s_addr = inet_addr( "192.168.0.1" ); 
	client_addr.sin_port = htons( PORT );
 
	//prevent bind error
	iSockOpt = 1;
	setsockopt(client_socket, SOL_SOCKET, SO_REUSEADDR, &iSockOpt, sizeof(iSockOpt));
 
	if( bind( client_socket, (struct sockaddr*)&client_addr, sizeof(client_addr) ) == -1 )
		error_handling("Bind ERROR!");
 
	file = fopen("recv.txt", "w");
 
	while(1)
	{
		client_size = sizeof(client_addr);
 
		str_len = recvfrom( client_socket, (char*)&meg, sizeof(meg), 0, (struct sockaddr*)&client_addr, &client_size );
 
		fprintf( file, "[#%2d] %s\n", meg.packetCnt, meg.message );
	}
 
	fclose( file );
	close( client_socket );
 
        return 0;
}
 
void error_handling(char *message)
{
	fputs(message, stderr);
	fputc('\n', stderr);
	exit(1);
}