udp 연결 단방향 전송 (서버가 연결된 udp 클라이언트에게만 데이터를 전송할 수 있음)

server.c
UDP 소켓에 클라이언트가 연결됨: 1.클라이언트만 서버에 데이터를 보낼 수 있습니다. 2.서비스 측은 서버처럼 데이터를 보낼 수 없습니다 (모든 발송 함수 포함)

#include 
#include 
#include 
#include           /* See NOTES */
#include 
#include 
#include 
#include 
#include 
#include 

typedef struct sockaddr	   sockaddr_t;
typedef struct sockaddr_in sockaddr_in_t;
typedef struct in6_addr	   in6_addr_t;
typedef	unsigned int		u32;
#define CUR				printf("%s : %d
", __FILE__, __LINE__);
#define SeverIP			"192.168.1.104" 
#define ClientIP		"192.168.1.107" 
#define THRAN_1024   	1025
#define PORT        	THRAN_1024

static int sfd, ret, len = sizeof(sockaddr_t);
static sockaddr_in_t server_addr;	//  
static sockaddr_in_t client_addr;	//  

/* ctr +c  */
static void sig_int(int sig)
{	close(sfd);
	exit(0);
}
#if 0 
void *work_sendto(void *arg)
{
	char buf[50];
	int ret;
	while (1) {
		memset(buf, 0, 50);
		fgets(buf, 50, stdin);	//  
		ret = sendto(sfd, buf, strlen(buf), 0, NULL, 0);	
		printf("s: %d
", ret);
	}
	pthread_exit(NULL);
}
#endif 

void *work_recvfrom(void *arg)
{
	char buf[50];
	int ret;
	while (1) {
		memset(buf, 0, 50);
		ret = recvfrom(sfd, buf, sizeof(buf), 0, NULL, 0);
		printf("recvfrom %d: %s", ret, buf);
		if (!ret) {
			perror("client shutdown");
			exit(0);
		}
	}
	pthread_exit(NULL);
}

int main(int argc, char **argv)
{	
	pthread_t tid_sendto, tid_recvfrom;	//  ID,  ID
	
	sfd = socket(AF_INET, SOCK_DGRAM, 0);

	signal(SIGINT, sig_int);
	
	//  
	memset(&server_addr, 0, sizeof(sockaddr_in_t));
	server_addr.sin_family = AF_INET;
	server_addr.sin_port = htons(PORT);					//  
	server_addr.sin_addr.s_addr = inet_addr(SeverIP);
	if(-1 == bind(sfd, (sockaddr_t *)&server_addr, len)) {
		perror("bind err");
		goto err;
	}
	
	/*  1  */
	/*  2  */
	//if(pthread_create(&tid_sendto, NULL, work_sendto, NULL))
		//perror("pthread_create err");
	//  UDP ,  
	if(pthread_create(&tid_recvfrom, NULL, work_recvfrom, NULL))
		perror("pthread_create err");
	
	pthread_join(tid_sendto, NULL);
	pthread_join(tid_recvfrom, NULL);
	return 0;
	
err:
	close(sfd);
	return -1;
}

client.c

#include 
#include 
#include 
#include           /* See NOTES */
#include 
#include 
#include 
#include 
#include 
#include 

typedef struct sockaddr	   sockaddr_t;
typedef struct sockaddr_in sockaddr_in_t;
typedef struct in6_addr	   in6_addr_t;
typedef	unsigned int		u32;
#define CUR				printf("%s : %d
", __FILE__, __LINE__);
#define SeverIP			"192.168.1.104"  
#define ClientIP		"192.168.1.107" 
#define THRAN_1024   	1025
#define PORT        	THRAN_1024

static int cfd, ret, len = sizeof(sockaddr_t);

static sockaddr_in_t server_addr, client_addr;	//  

/* ctr +c  */
static void sig_int(int sig)
{	close(cfd);
	exit(0);
}
void *work_sendto(void *arg)
{	int ret;
	char buf[50];
	while (1) {
		memset(buf, 0, 50);
		fgets(buf, 50, stdin);	//  
		ret = sendto(cfd, buf, strlen(buf), 0, NULL, 0);	//  ,  
		printf("sendto: %d
", ret);
	}
	pthread_exit(NULL);
}
void *work_recvfrom(void *arg)
{
	char buf[50];
	int ret;
	while (1) {
		memset(buf, 0, 50);
		CUR;
		ret = recvfrom(cfd, buf, sizeof(buf), 0, NULL, 0);
		CUR;
		printf("recvfrom %d: %s", ret, buf);
		if (!ret) {
			perror("server shutdown");
			exit(0);
		}
	}
	pthread_exit(NULL);
}

int main(int argc, char **argv)
{	
	pthread_t tid_sendto, tid_recvfrom;	//  ID,  ID
	
	cfd = socket(AF_INET, SOCK_DGRAM, 0);

	signal(SIGINT, sig_int);
	
	//  
	memset(&server_addr, 0, sizeof(sockaddr_in_t));
	server_addr.sin_family = AF_INET;
	server_addr.sin_port = htons(PORT);					//  
	server_addr.sin_addr.s_addr = inet_addr(SeverIP);

 	connect(cfd, (sockaddr_t *)&server_addr, len);
	/*  1  */
	/*  2  */
	
	if(pthread_create(&tid_sendto, NULL, work_sendto, NULL))
		perror("pthread_create err");
	if(pthread_create(&tid_recvfrom, NULL, work_recvfrom, NULL))
		perror("pthread_create err");
	
	pthread_join(tid_sendto, NULL);
	pthread_join(tid_recvfrom, NULL);
	return 0;
	
err:
	close(cfd);
	return -1;
}