리눅스 UDP 소켓

Linux API/network

리눅스 UDP 소켓

구차니 2019. 5. 24. 14:11

sento() 에 인자를 좀 바꾸어서 명령어줄 인자를 받으면 재미있긴 한데..

TCP 처럼 클라이언트 별로 accept 해주는 구조가 아니라

개별 클라이언트를 어떻게 구분해야 하지? 라고 고민중

server

// Server side implementation of UDP client-server model
#include
#include
#include
#include
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>

#define PORT     8080
#define MAXLINE 1024

// Driver code
int main() {
        int sockfd;
        char buffer[MAXLINE];
        char *hello = "Hello from server";
        struct sockaddr_in servaddr, cliaddr;

        // Creating socket file descriptor
        if ( (sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0 ) {
                perror("socket creation failed");
                exit(EXIT_FAILURE);
        }

        memset(&servaddr, 0, sizeof(servaddr));
        memset(&cliaddr, 0, sizeof(cliaddr));

        // Filling server information
        servaddr.sin_family = AF_INET; // IPv4
        servaddr.sin_addr.s_addr = INADDR_ANY;
        servaddr.sin_port = htons(PORT);

        // Bind the socket with the server address
        if ( bind(sockfd, (const struct sockaddr *)&servaddr,
                        sizeof(servaddr)) < 0 )
        {
                perror("bind failed");
                exit(EXIT_FAILURE);
        }

        while(1)
        {
        int len, n;
        n = recvfrom(sockfd, (char *)buffer, MAXLINE,
                                MSG_WAITALL, ( struct sockaddr *) &cliaddr,
                                &len);
        buffer[n] = '\0';
        printf("Client : %s\n", buffer);
//      sendto(sockfd, (const char *)hello, strlen(hello),
        sendto(sockfd, (const char *)buffer, strlen(buffer),
                MSG_CONFIRM, (const struct sockaddr *) &cliaddr,
                        len);
        printf("Hello message sent.\n");
        }
        return 0;
}

client

// Client side implementation of UDP client-server model
#include
#include
#include
#include
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>

#define PORT     8080
#define MAXLINE 1024

// Driver code
int main(int argc, char **argv) {
        int sockfd;
        char buffer[MAXLINE];
        char *hello = "Hello from client";
        struct sockaddr_in       servaddr;

        // Creating socket file descriptor
        if ( (sockfd = socket(AF_INET, SOCK_DGRAM, 0)) < 0 ) {
                perror("socket creation failed");
                exit(EXIT_FAILURE);
        }

        memset(&servaddr, 0, sizeof(servaddr));

        // Filling server information
        servaddr.sin_family = AF_INET;
        servaddr.sin_port = htons(PORT);
        servaddr.sin_addr.s_addr = INADDR_ANY;

        int n, len;

//      sendto(sockfd, (const char *)hello, strlen(hello),
        sendto(sockfd, (const char *)argv[1], strlen(argv[1]),
                MSG_CONFIRM, (const struct sockaddr *) &servaddr,
                        sizeof(servaddr));
        printf("Hello message sent.\n");

        n = recvfrom(sockfd, (char *)buffer, MAXLINE,
                                MSG_WAITALL, (struct sockaddr *) &servaddr,
                                &len);
        buffer[n] = '\0';
        printf("Server : %s\n", buffer);

        close(sockfd);
        return 0;
}

[링크 : https://www.geeksforgeeks.org/udp-server-client-implementation-c/]

[링크 : https://www.geeksforgeeks.org/tcp-and-udp-server-using-select/]

[링크 : https://scrapsquare.com/notes/udp-length]

[링크 : https://en.wikipedia.org/wiki/User_Datagram_Protocol]

class (cpp) 기반 UDP socket 예제

[링크 : http://youngmok.com/udp-server-c-class-listening-thread/]

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