網絡編程 - 本地socket

 示例流程圖：

 

 

 

/*****************************
* UDP-service.c
******************************/

#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>

#define UDP_PORT 58888
#define UDP_IP   "127.0.0.1"

int main(int argc, char **argv)
{
	int n;
	char recvline[1024] = {0};
        char sendline[1024] = {0};

	int sockfd;
	struct sockaddr_in service_addr;
        struct sockaddr_in client_addr;
        n = sizeof(struct sockaddr_in);

	/* 創建一個UDP連接的socket */
	sockfd = socket(PF_INET, SOCK_DGRAM, 0);

	/* 變量servaddr清零 */
	bzero(&service_addr, sizeof(service_addr));
	service_addr.sin_family = AF_INET;
	service_addr.sin_addr.s_addr = htonl(UDP_IP);	//指定IP
	service_addr.sin_port = htons(UDP_PORT);

	/* 綁定servaddr到創建的socket上 */
	bind(sockfd, (struct sockaddr *)&service_addr, sizeof(service_addr));


	/* 接收客戶端發送的數據 */
	recvfrom(sockfd, recvline, 1024, 0, (struct sockaddr_in)&client_addr, &n);

	printf("[service]: %s\n", recvline);
        
        /*  發送數據 */
        sprintf(sendline, "stop request");
	sendto(sockfd, sendline, strlen(sendline), 0, (struct sockaddr *)&client_addr,    sizeof(servaddr));
        

    /* 關閉socket連接 */
	close(sockfd);
    
        return 1;
}

/*****************************
* UDP-client.c
******************************/

#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>


#define UDP_PORT 58888
#define UDP_IP   "127.0.0.1"


int main(int argc, char **argv)
{
	int sockfd;
        int n = sizeof(struct sockaddr_in);
        char sendline[100] = {0};
	struct sockaddr_in servaddr;

	if(argc != 2)
	{
			printf("usgae: ./client [ip]\n");

			return -1;
	}

	/* 創建一個UDP的socket連接 */
	sockfd = socket(PF_INET, SOCK_DGRAM, 0);

	/* 變量servaddr清零 */
	bzero(&servaddr, sizeof(servaddr));
	servaddr.sin_family = AF_INET;
	servaddr.sin_port = htons(UDP_PORT);
	servaddr.sin_addr.s_addr = inet_addr(UDP_IP);

	char sendline[100];
	sprintf(sendline, "Hello, world!");

	/*  發送數據 */
	sendto(sockfd, sendline, strlen(sendline), 0, (struct sockaddr *)&servaddr,  sizeof(servaddr));
        
        /* 接收客戶端發送的數據 */
	recvfrom(sockfd, recvline, sizeof(recvline), 0, (struct sockaddr *)&servaddr, &n);
        printf("[client]: %s\n",recvline);

	/* 關閉socket連接 */
	close(sockfd);

	return 1;
}