shortener-bot/DPP/include/dpp/dns.h

98 lines
2.8 KiB
C++

/************************************************************************************
*
* D++, A Lightweight C++ library for Discord
*
* Copyright 2021 Craig Edwards and D++ contributors
* (https://github.com/brainboxdotcc/DPP/graphs/contributors)
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
************************************************************************************/
#pragma once
#include <dpp/export.h>
#ifdef _WIN32
#include <WinSock2.h>
#include <WS2tcpip.h>
#else
#include <netinet/in.h>
#include <netdb.h>
#include <sys/socket.h>
#endif
#include <sys/types.h>
#include <string>
#include <unordered_map>
#include <cstring>
#include <dpp/socket.h>
namespace dpp {
/**
* @brief Represents a cached DNS result.
* Used by the ssl_client class to store cached copies of dns lookups.
*/
struct dns_cache_entry {
/**
* @brief Resolved address metadata
*/
addrinfo addr;
/**
* @brief Resolved address as string.
* The metadata is needed to know what type of address it is.
* Do not do silly stuff like just looking to see if '.' is in it!
*/
std::string resolved_addr;
/**
* @brief Time at which this cache entry is invalidated
*/
time_t expire_timestamp;
/**
* @brief Get address length
* @return address length
*/
[[nodiscard]] int size() const;
/**
* @brief Get the address_t that corresponds to this cache entry
* for use when connecting with ::connect()
* @param port Port number to connect to
* @return address_t prefilled with the IP and port number
*/
[[nodiscard]] const address_t get_connecting_address(uint16_t port) const;
/**
* @brief Allocate a socket file descriptor for the given dns address
* @return File descriptor ready for calling connect(), or INVALID_SOCKET
* on failure.
*/
[[nodiscard]] socket make_connecting_socket() const;
};
/**
* @brief Cache container type
*/
using dns_cache_t = std::unordered_map<std::string, dns_cache_entry*>;
/**
* @brief Resolve a hostname to an addrinfo
*
* @param hostname Hostname to resolve
* @param port A port number or named service, e.g. "80"
* @return dns_cache_entry* First IP address associated with the hostname DNS record
* @throw dpp::connection_exception On failure to resolve hostname
*/
const dns_cache_entry* resolve_hostname(const std::string& hostname, const std::string& port);
}