RAW SOCKET에 대해 질문이 있습니다. ^^

sock = socket(PF_INET, SOCK_RAW, IPPROTO_TCP);
    if(sock == INVALID_SOCKET) {
        errorHandling("socket() error");
    }
 
    setsockopt(sock,  IPPROTO_IP, IP_HDRINCL, (char *)&flag, sizeof(flag));
    addr_len = sizeof(servAddr);
 
    memset(&servAddr, 0x00, sizeof(servAddr));
 
    while(1) {
        memset(&servAddr, 0x00, sizeof(servAddr));
        memset(packet, 0x00, 1024);
        readLen = recvfrom(sock, packet, BUFSIZE, 0, (SOCKADDR *)&servAddr, &addr_len);
        if(readLen == SOCKET_ERROR) {
            errorHandling("recvfrom() errror");
        }
        ip = (IPHDR *)packet;
        printf("src ip : %s\n", inet_ntoa(ip->source));
        printf("dst ip : %s\n", inet_ntoa(ip->dest));
    }