UDP編程模型

1 UDP編程模型

UDP編程模型如下：

UDP編程示例代碼：

udp_server.c：

//服務器端代碼 server.c
#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <arpa/inet.h>
 
int main(int argc, char **argv)
{
	int ret;
    struct sockaddr_in servaddr;
    char recvline[1024];
									//SOCK_STREAM
    int sockfd = socket(PF_INET, SOCK_DGRAM, 0);
 
    //服務器 ip port
    bzero(&servaddr, sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_addr.s_addr = htonl(INADDR_ANY);
    servaddr.sin_port = htons(50001);
 
    //fcntl(sockfd, F_SETFL,O_NONBLOCK);//設置爲非阻塞，根據具體需要決定是否需要非阻塞模式
    bind(sockfd, (struct sockaddr *)&servaddr, sizeof(servaddr));
    while(1)
    {
        struct sockaddr_in addrClient;
        int sizeClientAddr = sizeof(struct sockaddr_in);
        ret = recvfrom(sockfd, recvline, 1024, 0, (struct sockaddr*)&addrClient,(socklen_t*)&sizeClientAddr);
        char *pClientIP =inet_ntoa(addrClient.sin_addr);
 
        printf("%s-%d(%d) says:%s\n",pClientIP,ntohs(addrClient.sin_port),addrClient.sin_port, recvline);
		
		sendto(sockfd, recvline, ret, 0, (struct sockaddr *)&addrClient, sizeClientAddr);
    }
    close(sockfd);
}

udp_client.c：

//客戶端代碼 client.c
#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <arpa/inet.h>
 
int main(int argc,char **argv)
{
	int ret;
	char recvline[1024];
    int sockfd = socket(PF_INET, SOCK_DGRAM, 0);
    //server ip port
    struct sockaddr_in servaddr;
    struct sockaddr_in client_addr;
    char sendline[100] = "hello world!";
	
    bzero(&servaddr,sizeof(servaddr));
    servaddr.sin_family = AF_INET;
    servaddr.sin_port = htons(50001);
    servaddr.sin_addr.s_addr = inet_addr("127.0.0.1");
    //my ip port (bind),也可以不綁定本地port，那麼本地發送的port就是隨機的。
    
    bzero(&client_addr,sizeof(client_addr));
    client_addr.sin_family = AF_INET;
    client_addr.sin_port = htons(40001);
    client_addr.sin_addr.s_addr = htonl(INADDR_ANY);
    //client發出的udp包就是從這個port發出
    
    if(bind(sockfd, (struct sockaddr *)&client_addr,sizeof(client_addr))<0)
    {
        printf("video rtcp bind ret < 0\n");
    }
    sendto(sockfd, sendline, strlen(sendline) + 1, 0, (struct sockaddr *)&servaddr,sizeof(servaddr));
	
	while(1)
    {
        struct sockaddr_in addrClient;
        int sizeClientAddr = sizeof(struct sockaddr_in);
        ret = recvfrom(sockfd, recvline, 1024, 0, (struct sockaddr*)&addrClient,(socklen_t*)&sizeClientAddr);
        char *pClientIP =inet_ntoa(addrClient.sin_addr);
 
        printf("%s-%d(%d) says:%s\n",pClientIP,ntohs(addrClient.sin_port),addrClient.sin_port, recvline);
		
		sendto(sockfd, recvline, ret, 0, (struct sockaddr *)&addrClient, sizeClientAddr);
    }
	
    close(sockfd);
    return 1;
}

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參考資料：

1. 5G物聯網雲平臺智能家居項目30天搞定