UDP (C++)

UDP 

- 패킷 순서 보장 안함

- 니는 받아라 내는 보낼란다 마인드

- TCP 보다 빠름

- 보통 영상 데이터 송수신시 사용

UDP Server

//////////// Server.cpp /////////////

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <arpa/inet.h>

#include <unistd.h>

#include <iostream>

using namespace std;

#define BUFSIZE 512

int main()

{

int sock=socket(AF_INET, SOCK_DGRAM, 0);

int retval;

sockaddr_in serveraddr;

bzero(&serveraddr, sizeof(serveraddr));

serveraddr.sin_family=AF_INET;

serveraddr.sin_port=htons(9000);

serveraddr.sin_addr.s_addr=htonl(INADDR_ANY);

retval=bind(sock, (sockaddr*)&serveraddr, sizeof(serveraddr));

sockaddr_in clientaddr;

int addrlen;

char buf[BUFSIZE+1];

while(1)

{

addrlen=sizeof(clientaddr);

retval=recvfrom(sock,buf,BUFSIZE,0,(sockaddr*)&clientaddr,

(socklen_t*)&addrlen);

buf[retval]='\0';

cout<<"[UDP/"<<inet_ntoa(clientaddr.sin_addr)<<":"

<<ntohs(clientaddr.sin_port)<<"] "<<buf<<endl;

retval=sendto(sock,"send to client",retval,0,(sockaddr*)&clientaddr, sizeof(clientaddr));

}

close(sock);

return 0;

}

UDP Client

//////////// Client.cpp /////////////

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <sys/types.h>

#include <sys/socket.h>

#include <arpa/inet.h>

#include <unistd.h>

#include <iostream>

using namespace std;

#define BUFSIZE 512

int main()

{

    int sock=socket(AF_INET, SOCK_DGRAM, 0);

    

    sockaddr_in serveraddr;

    bzero(&serveraddr, sizeof(serveraddr));

    serveraddr.sin_family=AF_INET;

    serveraddr.sin_port=htons(9000);

    serveraddr.sin_addr.s_addr=inet_addr("127.0.0.1");

    

    char buf[BUFSIZE + 1] = "";

    double tempLat = 34.611021;

    double tempLon = 127.2046907;

    float tempHeading = 10;

    float tempAlt = 0;

    

     while(1)

     {

        cout<<endl<<"[send data] ";

        

        char temp[BUFSIZE + 1];

        

        memset(&buf, 0, sizeof(buf));

                

        sprintf(temp, "%lf ", tempLat);

        strcat(buf, temp);

        sprintf(temp, "%lf ", tempLon);

        strcat(buf, temp);

        sprintf(temp, "%lf ", tempHeading);

        strcat(buf, temp);

        sprintf(temp, "%lf ", tempAlt);

        strcat(buf, temp);

    

        int retval;

        retval=sendto(sock,buf,strlen(buf),0,(sockaddr*)&serveraddr,sizeof(serveraddr));

        cout<<"[UDP client] "<<retval<<"send byte"<<endl;

        

        usleep(1000000);

                

        tempLat = tempLat + 0.000001;

        tempLon = tempLon + 0.0000001;

        tempHeading = tempHeading + 0.5;

        tempAlt = tempAlt + 1;

     }

    

     close(sock);

     return 0;

}