简单的UDP套接字编程例子

UDP系统调用时序图

简单的UDP例子

/*
 ============================================================================
 Name        : UDPclient.c
 Author      : vestinfo
 Version     : 1.1
 Copyright   : Your copyright notice
 Description : A simple UDP client, Ansi-style
 ============================================================================
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/socket.h>


#define REMOTEPORT 8888
#define REMOTEIP "127.0.0.1"

#define CLIENT_PORT 9999
#define CLIENT_IP "192.168.77.172"

int main(int argc,char *argv[])
{
	int sockfd;
	struct sockaddr_in servaddr;
	struct sockaddr_in clientaddr;
	int addr_len;
	char msg[256];
	int i=0;

	if(( sockfd = socket(AF_INET,SOCK_DGRAM,0))<0)
	{
		perror("error");
		exit(1);
	}

	bzero(&clientaddr, sizeof(clientaddr));
	clientaddr.sin_family=AF_INET;
	clientaddr.sin_port=htons(CLIENT_PORT);
	clientaddr.sin_addr.s_addr=inet_addr(CLIENT_IP);

	if(bind(sockfd, (struct sockaddr *)&clientaddr, sizeof(clientaddr)) < 0)
	{
		perror("error");
		exit(1);
	}

	addr_len=sizeof(struct sockaddr);
	bzero(&servaddr,sizeof(servaddr));

	servaddr.sin_family=AF_INET;
	servaddr.sin_port=htons(REMOTEPORT);
	servaddr.sin_addr.s_addr=inet_addr(REMOTEIP);

	while(1)
	{
		bzero(msg,sizeof(msg));

		read(STDIN_FILENO,msg,sizeof(msg));												//从键盘（终端）键入msg

		sendto(sockfd,msg,sizeof(msg),0,(struct sockaddr *)&servaddr,addr_len);		//发送msg给目的套接字addr

		recvfrom(sockfd,msg,sizeof(msg),0,(struct sockaddr *)&servaddr,&addr_len);//接受目的套接字传来的msg
		printf("Received message from server:%s\n",msg);
	}

}

隐藏行号 复制代码 ？ server

1. /*
   

2.  ============================================================================
   

3.  Name        : UDPserver.c
   

4.  Author      : vestinfo
   

5.  Version     : 1.1
   

6.  Copyright   : Your copyright notice
   

7.  Description : A simple UDP server, Ansi-style
   

8.  ============================================================================
   

9.  */
   

11. #include <stdio.h>
    

12. #include <stdlib.h>
    

13. #include <string.h>
    

14. #include <netinet/in.h>
    

15. #include <arpa/inet.h>
    

16. #include <unistd.h>
    

17. #include <sys/stat.h>
    

18. #include <sys/types.h>
    

19. #include <sys/socket.h>
    

21. #define LOCALPORT 8888
    

23. int main(int argc,char *argv[])
    

24. {
    

25. int sockfd;
    

26. struct sockaddr_in addr;
    

27. char msg[256];
    

28. int addr_len;
    

30. if((sockfd=socket(AF_INET,SOCK_DGRAM,0)) < 0)
    

31.     {
    

32. perror("error");
    

33. exit(1);
    

34.     }
    

36.     addr_len=sizeof(struct sockaddr);
    

37. bzero(&addr,sizeof(addr));
    

38.     addr.sin_family = AF_INET;
    

39.     addr.sin_port = htons(LOCALPORT);
    

40.     addr.sin_addr.s_addr = htonl(INADDR_ANY);
    

42. if(bind(sockfd, (struct sockaddr *)&addr, sizeof(addr)) < 0)
    

43.     {
    

44. perror("error");
    

45. exit(1);
    

46.     }
    

48. printf("UDP server waiting for client...\n");
    

50. while(1)
    

51.     {
    

52. bzero(msg,sizeof(msg));
    

53. recvfrom(sockfd,msg,sizeof(msg),0,(struct sockaddr *)&addr,&addr_len);
    

55. printf("Received message from:%s\n",inet_ntoa(addr.sin_addr));
    

56. printf("The message Received from client:%s",msg);
    

58. sendto(sockfd,msg,sizeof(msg),0,(struct sockaddr *)&addr,addr_len);
    

59.     }
    

60. }