英文:
boost::asio - is it possible to bind to a local device (equivalent of SO_BINDTODEVICE) rather than local address?
问题
我想绑定到本地接口，例如 "eth0"，使用 boost::asio。
使用底层套接字接口的等效代码如下：
const std::string ifc = "eth0";
struct ifreq ifr;
bzero(&ifr, sizeof(ifr));
memcpy(ifr.ifr_name, ifc.c_str(), ifc.length());
if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, static_cast<void*>(&ifr), sizeof(ifr)) < 0)
{
throw std::runtime_error("bind to local interface failed");
}
然而，当我尝试将本地接口传递给 boost::asio::ip::tcp::resolver 时，它无法解析它：
using tcp = boost::asio::ip::tcp;
const std::string ifc = "eth0";
auto ctx = socket.get_executor();
tcp::resolver resolver(ctx);
tcp::resolver::results_type results = resolver.resolve(ifc, "");
这会引发异常，异常描述为 "Host not found (authoritative)"。
根据错误消息的内容，似乎它正在尝试将接口解析为主机地址。
是否可以使用 boost::asio 来执行类似 SO_BINDTODEVICE 的操作呢？
英文:
I would like to bind to a local interface, eg "eth0", using boost::asio.
The equivalent code using the low level socket interface would be:
const std::string ifc = "eth0";
struct ifreq ifr;
bzero(&ifr, sizeof(ifr));
memcpy(ifr.ifr_name, ifc.c_str(), ifc.length());
if (setsockopt(fd, SOL_SOCKET, SO_BINDTODEVICE, static_cast<void*>(&ifr), sizeof(ifr)) < 0)
{
throw std::runtime_error("bind to local interface failed");
}
However, when I attempt to pass a local interface to the boost::asio::ip::tcp::resolver, it can't resolve it:
using tcp = boost::asio::ip::tcp;
const std::string ifc = "eth0";
auto ctx = socket.get_executor();
tcp::resolver resolver(ctx);
tcp::resolver::results_type results = resolver.resolve(ifc, "");
This throws an exception, with description "Host not found (authoritative)"
By the content of the error message it does sound like it's attempting to resolve the interface as a host address.
Is it possible to do the equivalent of SO_BINDTODEVICE using boost::asio?
答案1
得分: 2
不能使用boost::asio来实现类似于SO_BINDTODEVICE的功能，但你可以像平常一样使用选项。
if (setsockopt(socket.native_handle(), SOL_SOCKET, SO_BINDTODEVICE, static_cast<void*>(&ifr), sizeof(ifr)) < 0)
你也可以定义自己的自定义选项以使其更“漂亮”，但我可能只会在这是一种经常重复的代码时才这样做。
英文:
> Is it possible to do the equivalent of SO_BINDTODEVICE using boost::asio?
No, but you can use the option like you're used to.
if (setsockopt(socket.native_handle(), SOL_SOCKET, SO_BINDTODEVICE, static_cast<void*>(&ifr), sizeof(ifr)) < 0)
You could also define your own custom option to make it "prettier", but I would probably only do this if this is somehow oft-repeating code.
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