linux 환경에서 udp 소켓통신을 하는데요..

클라이언트에서 서버로 send는 현재 되는데

서버에서 클라이언트로 보내는 과정에서 안됩니다..

아래 현재 소스를 올리겠습니다..

소스가 길지만 .. 거의 템플릿 수준이니까.. 잠시만 봐주시면

감사하겠어요..

그럼.

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <unistd.h>
#include <netinet/in.h>
#include <signal.h>

struct data
{
    int a;
    int b;
    int sum;
    int test[5];
};

int main(int argc, char **argv)
{
    int sockfd;
    int clilen;
    int state;
    int n;
    int sum;
    struct data add_data;

    struct sockaddr_un serveraddr, clientaddr;

    signal(SIGCHLD,SIG_IGN);
    clilen = sizeof(clientaddr);
    sockfd = socket(PF_LOCAL, SOCK_DGRAM, 0);
    if (sockfd < 0)
    {
        perror("socket error : ");
        exit(0);
    }
    memset(&serveraddr,0,sizeof(serveraddr));
//    bzero(&serveraddr, sizeof(serveraddr));
    //serveraddr.sin_family = AF_LOCAL;
    serveraddr.sun_family = AF_LOCAL;
    //strcpy(serveraddr.sun_path,"/home/facered/EXAM7/sum_server");
    strcpy(serveraddr.sun_path,"sum_server1");
//    serveraddr.sin_addr.s_addr = htonl(INADDR_ANY);
//    serveraddr.sin_port = htons(1234);
    unlink("sum_server1");
    state = bind(sockfd, (struct sockaddr *)&serveraddr,
        sizeof(serveraddr));
    if (state == -1)
    {
        perror("bind error : ");
        exit(0);
    }
    while(1)
    {
        n = recvfrom(sockfd, (void *)&add_data, sizeof(add_data), 0, (struct sockaddr *)&clientaddr, &clilen);
        printf("n is %d\n",n);
        add_data.sum = add_data.a + add_data.b;
        n=sendto(sockfd, (void *)&add_data, sizeof(add_data), 0, (struct sockaddr *)&clientaddr, clilen);
        printf("n is %d\n",n);
    }
    close(sockfd);
}

클라이언트

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <unistd.h>
#include <netinet/in.h>
#include <sys/un.h>

struct data
{
    int a;
    int b;
    int sum;
    int test[5];
};
int main(int argc, char **argv)
{
    int sockfd;
    int clilen;
    int servlen;
    int state;
    char buf[255];

    struct sockaddr_un serveraddr,cli_addr;
    struct data add_data;


    memset(buf, 0x00, 255);

    add_data.test[0]=2;

    bzero(&serveraddr, sizeof(serveraddr));
    serveraddr.sun_family = AF_LOCAL;
    strcpy(serveraddr.sun_path,"sun_server1");

    servlen = sizeof(serveraddr);

    sockfd = socket(PF_LOCAL, SOCK_DGRAM, 0);
    if (sockfd < 0)
    {
        perror("socket error : ");
        exit(0);
    }
    
    bzero(&cli_addr,sizeof(cli_addr));
    cli_addr.sun_family=AF_LOCAL;
    strcpy(cli_addr.sun_path,"sum");
    mkstemp(cli_addr.sun_path);
    clilen = strlen(cli_addr.sun_path) + sizeof(cli_addr.sun_family);

    serveraddr.sun_family = AF_LOCAL;
    strcpy(serveraddr.sun_path, "sum_server1");

    add_data.a = atoi(argv[1]);
    add_data.b = atoi(argv[2]);

    if(sendto(sockfd, (void *)&add_data, sizeof(add_data), 0, (struct sockaddr *)&serveraddr, servlen)==-1)
        printf("error cant send\n");

    if(recvfrom(sockfd, (void *)&add_data, sizeof(add_data), 0, NULL, NULL)==-1)
        printf("error cant recv\n");


    printf("--> %d + %d = %d\n", add_data.a, add_data.b, add_data.sum);
    close(sockfd);
}