c-来自任何有效地址的ipv4和ipv6

我正在尝试从任何字符串地址获取ipv4和ipv6地址,无论是通过ipv4,ipv6还是DNS地址.

我可以创建自己的函数来执行此操作,但是我尝试使用expert advice并利用内置功能.

有没有办法输入任何格式的地址字符串,并同时返回ipv4和ipv6提升地址？

解决方法:

从DNS名称获取地址涉及…查询命名服务器(DNS！).如果要枚举结果,请在asio中使用解析器：

> http://www.boost.org/doc/libs/1_55_0/doc/html/boost_asio/reference/ip__tcp/resolver.html

简单的例子：

#include <boost/asio.hpp>
#include <boost/function_output_iterator.hpp>
#include <set>

using boost::asio::ip::address;

std::set<address> unique_endpoints(std::string const& ip)
{
    using resolver = boost::asio::ip::tcp::resolver;
    boost::asio::io_service ios; // TODO use existing service / resolver
    resolver r(ios);

    std::set<address> unique;
    for (auto it = r.resolve({ip, ""}); it != resolver::iterator {}; ++it)
    {
        //std::cout << "Resolved: " << it->host_name() << " -> " << it->endpoint() << " " << it->service_name() << "\n";
        address a = it->endpoint().address();
        if (a.is_v4())
            unique.insert(boost::asio::ip::address_v6::v4_mapped(a.to_v4()));
        else
            unique.insert(a);
    }

    return unique;
}

template <typename S>
bool endpoints_overlap(S const& a, S const& b)
{
    bool matching_found = false;

    std::set_intersection(
            a.begin(), a.end(), b.begin(), b.end(),
            boost::make_function_output_iterator([&](address const&) { matching_found = true; }));

    return matching_found;
}

int main()
{
    auto h = unique_endpoints("bbs2.fritz.box");
    auto a = unique_endpoints("192.168.2.111");
    auto b = unique_endpoints("::ffff:192.168.2.111");
    auto c = unique_endpoints("::ffff:c0a8:026f");

    assert(endpoints_overlap(a, b));
    assert(endpoints_overlap(a, c));
    assert(endpoints_overlap(b, c));

    assert(endpoints_overlap(h, a));
    assert(endpoints_overlap(h, b));
    assert(endpoints_overlap(h, c));
}

请注意,当DNS响应之一匹配时,此测试将确定端点重叠.这在群集设置中可能并不总是正确的(？那里没有专家),并且您可能还想在使用此算法之前检测广播地址(未经测试).

另请注意,我认为没有办法检测实际主机的等效性(这意味着,如果主机具有多个物理/逻辑NIC,它们将在传输级别上显示为单独的服务器).

最后,在实际应用程序中,您将需要异步进行解析(使用async_resolve)

标签：boost,boost-asio,ip-address,linux,c-4
来源： https://codeday.me/bug/20191029/1960109.html