s

#include"net.h"
int main(int argc, const char *argv[])
{
    int fd = -1;
    struct sockaddr_in sin;
    //1
    if((fd = socket(AF_INET,SOCK_DGRAM,0)) < 0)
    {
        perror("socket");
        exit(1);
    }
    //2youhua
    int b_reuse = 1;
    setsockopt(fd,SOL_SOCKET,SO_REUSEADDR,&b_reuse,sizeof(int));
    //3tianchong
    bzero(&sin,sizeof(sin));
    sin.sin_family = AF_INET;
    sin.sin_port = htons(SERV_PORT);
    sin.sin_addr.s_addr = htonl(INADDR_ANY);
    //4
    if(bind(fd,(struct sockaddr *)&sin,sizeof(sin)) < 0)
    {
        perror("bind");
        exit(1);
    }
    printf("server staring...ok\n");
    //5
    char buf[BUFSIZ];
    struct sockaddr_in cin;
    socklen_t addrlen = sizeof(sin);
    while(1)
    {
        bzero(buf,BUFSIZ);
        if(recvfrom(fd,buf,BUFSIZ-1,0,(struct sockaddr *)&cin,&addrlen) < 0)
        {
            perror("recvfrom");
            continue;
        }
        char ipv4_addr[16];
        if(!inet_ntop(AF_INET,(void *)&cin.sin_addr,ipv4_addr,sizeof(cin)))
        {
            perror("inet_ntop");
            exit(1);
        }
        printf("Recived from(%s:%d),data:%s",ipv4_addr,ntohs(sin.sin_port),buf);
        if(!strncasecmp(buf,QUIT_STR,strlen(QUIT_STR)))
        {
            printf("Client(%s:%d) is exiting\n",ipv4_addr,ntohs(sin.sin_port));
        }
    }
    close(fd);
    return 0;
}