有什么方法可以省略此 portscanner 代码中 int_to_string 转换函数的使用

Question

我试图检查主机的端口从 0 到 1024 是否打开。我使用 getaddrinfo(const char*node, const char *service, const struct addrinfo *hints, struct addrinfo **res) 将端口号从 0 循环到 1024（即第二个参数 const char *service），方法是将 int 转换为字符串，然后传递给 getaddrinfo()。有什么办法可以避免使用这个转换函数吗？

char *convert_int_to_string(int num)
{
    int tmp;
    int i = 0;
    int j = 0;
    static char a[5] = {'0'};

    while (num > 0) {
        tmp = num % 10;
        a[i++] = tmp + '0';
        num = num / 10;
    }
    a[i] = '[=11=]';
    for (j = 0; j < i / 2; j++) {
        tmp = a[j];
        a[j] = a[i - j - 1];
        a[i - j - 1] = tmp;
    }
    return a;
}


int main(int argc, char **argv)
{
    int status;
    char *node;
    char *port_no;
    int sock_fd;
    int i = 0;
    struct  addrinfo hints, *serviceinfo;

    if (argc != 2)
        error(1, errno, "Too many or few arguments\n");
    node = argv[1];
    memset(&hints, 0, sizeof hints);
    hints.ai_family = AF_INET;
    hints.ai_socktype = SOCK_STREAM;
    for (i = 0; i < 1024; i++) {
        port_no = convert_int_to_string(i);
        status = getaddrinfo(node, port_no, &hints, &serviceinfo);
        if (status != 0) {
            error(1, errno, "error in getaddrinfo() function call\n");
        }
        sock_fd = socket(serviceinfo->ai_family, serviceinfo->ai_socktype, serviceinfo->ai_protocol);
        if (sock_fd == -1)
            error(1, errno, "error in socket() function call\n");
        status = connect(sock_fd, serviceinfo->ai_addr, serviceinfo->ai_addrlen);
        if (status != -1)
            printf("Port : %s is open\n", port_no);
        else
            printf("Port : %s is closed\n", port_no);
    }
}

Answer 1

Is there any way to omit the usage of int_to_string conversion function in this portscanner code (?)

是用snprintf()组成port_no。

for (i = 0; i < 1024; i++) {
   // port_no = convert_int_to_string(i);
   char port_no[40];
   snprintf(port_no, sizeof port_no, "%d", i);
   ...

有什么方法可以省略此 portscanner 代码中 int_to_string 转换函数的使用

Is there any way to omit the usage of int_to_string conversion function in this portscanner code

c

unix

linux

networking

network-programming