/**
* This constructor is typically used to perform name resolution for
* communication with remote hosts.
*
* @param host A string identifying a location. May be a descriptive name or
* a numeric address string. If an empty string and the passive flag has been
* specified, the resolved endpoints are suitable for local service binding.
* If an empty string and passive is not specified, the resolved endpoints
* will use the loopback address.
*
* @param service A string identifying the requested service. This may be a
* descriptive name or a numeric string corresponding to a port number. May
* be an empty string, in which case all resolved endpoints will have a port
* number of 0.
*
* @param resolve_flags A set of flags that determine how name resolution
* should be performed. The default flags are suitable for communication with
* remote hosts.
*
* @note On POSIX systems, host names may be locally defined in the file
* <tt>/etc/hosts</tt>. On Windows, host names may be defined in the file
* <tt>c:\\windows\\system32\\drivers\\etc\\hosts</tt>. Remote host name
* resolution is performed using DNS. Operating systems may use additional
* locations when resolving host names (such as NETBIOS names on Windows).
*
* On POSIX systems, service names are typically defined in the file
* <tt>/etc/services</tt>. On Windows, service names may be found in the file
* <tt>c:\\windows\\system32\\drivers\\etc\\services</tt>. Operating systems
* may use additional locations when resolving service names.
*/
basic_resolver_query(const std::string& host, const std::string& service,
resolver_query_base::flags resolve_flags = address_configured)
: hints_(),
host_name_(host),
service_name_(service)
{
typename InternetProtocol::endpoint endpoint;
hints_.ai_flags = static_cast<int>(resolve_flags);
hints_.ai_family = BOOST_ASIO_OS_DEF(AF_UNSPEC);
hints_.ai_socktype = endpoint.protocol().type();
hints_.ai_protocol = endpoint.protocol().protocol();
hints_.ai_addrlen = 0;
hints_.ai_canonname = 0;
hints_.ai_addr = 0;
hints_.ai_next = 0;
}
/// Obtain an identifier for the type of the protocol.
int type() const
{
return BOOST_ASIO_OS_DEF(SOCK_STREAM);
}
/// Obtain an identifier for the protocol.
int protocol() const
{
return BOOST_ASIO_OS_DEF(IPPROTO_UDP);
}
/// Construct to represent the IPv6 UDP protocol.
static udp v6()
{
return udp(BOOST_ASIO_OS_DEF(AF_INET6));
}
/// Obtain an identifier for the type of the protocol.
int type() const
{
return BOOST_ASIO_OS_DEF(SOCK_RAW);
}
/// Construct to represent the IPv6 ICMP protocol.
static icmp v6()
{
return icmp(BOOST_ASIO_OS_DEF(IPPROTO_ICMPV6),
BOOST_ASIO_OS_DEF(AF_INET6));
}
/// Construct to represent the IPv4 ICMP protocol.
static icmp v4()
{
return icmp(BOOST_ASIO_OS_DEF(IPPROTO_ICMP),
BOOST_ASIO_OS_DEF(AF_INET));
}
// Get the name of the IO control command.
int name() const
{
return static_cast<int>(BOOST_ASIO_OS_DEF(FIONREAD));
}
/// Construct to represent the IPv6 TCP protocol.
static tcp v6()
{
return tcp(BOOST_ASIO_OS_DEF(AF_INET6));
}
// Determine whether the endpoint is IPv4.
bool is_v4() const
{
return data_.base.sa_family == BOOST_ASIO_OS_DEF(AF_INET);
}
/// Construct to represent the version 1 Fiber protocol.
static datagram_fiber v1()
{
return datagram_fiber(BOOST_ASIO_OS_DEF(AF_INET));
}
/// Construct to represent the version 1 Fiber protocol.
static stream_fiber v1()
{
return stream_fiber(BOOST_ASIO_OS_DEF(AF_INET));
}
/// Obtain an identifier for the type of the protocol.
int type() const
{
return BOOST_ASIO_OS_DEF(SOCK_SEQPACKET);
}