IpNetwork.cpp

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/*
 * This file is part of the TrinityCore Project. See AUTHORS file for Copyright information
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program. If not, see <http://www.gnu.org/licenses/>.
 */
 
#include "IpNetwork.h"
#include "IpAddress.h"
#include <boost/asio/ip/network_v4.hpp>
#include <boost/asio/ip/network_v6.hpp>
#include <algorithm>
 
namespace
{
std::vector<boost::asio::ip::network_v4> LocalV4Networks;
std::vector<boost::asio::ip::network_v6> LocalV6Networks;
}
 
namespace Trinity::Net
{
bool IsInLocalNetwork(boost::asio::ip::address const& clientAddress)
{
 if (clientAddress.is_v4())
 {
 return std::any_of(LocalV4Networks.begin(), LocalV4Networks.end(), [clientAddressV4 = clientAddress.to_v4()](boost::asio::ip::network_v4 const& network)
 {
 return IsInNetwork(network, clientAddressV4);
 });
 }
 
 if (clientAddress.is_v6())
 {
 return std::any_of(LocalV6Networks.begin(), LocalV6Networks.end(), [clientAddressV6 = clientAddress.to_v6()](boost::asio::ip::network_v6 const& network)
 {
 return IsInNetwork(network, clientAddressV6);
 });
 }
 
 return false;
};
 
bool IsInNetwork(boost::asio::ip::network_v4 const& network, boost::asio::ip::address_v4 const& clientAddress)
{
 if (clientAddress == network.address())
 return true;
 
 boost::asio::ip::network_v4 endpointAsNetwork = boost::asio::ip::make_network_v4(clientAddress, 32);
 return endpointAsNetwork.is_subnet_of(network);
}
 
bool IsInNetwork(boost::asio::ip::network_v6 const& network, boost::asio::ip::address_v6 const& clientAddress)
{
 if (clientAddress == network.address())
 return true;
 
 boost::asio::ip::network_v6 endpointAsNetwork = boost::asio::ip::make_network_v6(clientAddress, 128);
 return endpointAsNetwork.is_subnet_of(network);
}
 
Optional<std::size_t> SelectAddressForClient(boost::asio::ip::address const& clientAddress, std::span<boost::asio::ip::address const> const& addresses)
{
 Optional<std::size_t> localIpv6Index;
 Optional<std::size_t> externalIpv6Index;
 Optional<std::size_t> loopbackIpv6Index;
 Optional<std::size_t> localIpv4Index;
 Optional<std::size_t> externalIpv4Index;
 Optional<std::size_t> loopbackIpv4Index;
 
 for (std::size_t i = 0; i < addresses.size(); ++i)
 {
 boost::asio::ip::address const& address = addresses[i];
 
 if (address.is_loopback())
 {
 if (address.is_v6() && !loopbackIpv6Index)
 loopbackIpv6Index = i;
 
 if (address.is_v4() && !loopbackIpv4Index)
 loopbackIpv4Index = i;
 }
 else if (IsInLocalNetwork(address))
 {
 if (address.is_v6() && !localIpv6Index)
 localIpv6Index = i;
 
 if (address.is_v4() && !localIpv4Index)
 localIpv4Index = i;
 }
 else
 {
 if (address.is_v6() && !externalIpv6Index)
 externalIpv6Index = i;
 
 if (address.is_v4() && !externalIpv4Index)
 externalIpv4Index = i;
 }
 }
 
 if (IsInLocalNetwork(clientAddress) || clientAddress.is_loopback())
 {
 // client is in the same network as this process, prefer local addresses
 
 // first, try finding a local ipv6 address
 if (clientAddress.is_v6() && localIpv6Index)
 {
 // we have a usable ipv6 local address
 return localIpv6Index;
 }
 
 // we dont have a local v6, return local v4
 if (localIpv4Index)
 return localIpv4Index;
 }
 
 if (clientAddress.is_loopback())
 {
 // fallback, search for a loopback address in configuration
 if (clientAddress.is_v6() && loopbackIpv6Index)
 return loopbackIpv6Index;
 
 if (loopbackIpv4Index)
 return loopbackIpv4Index;
 }
 
 // client is NOT in the same network as this process
 if (clientAddress.is_v6() && externalIpv6Index)
 return externalIpv6Index;
 
 return externalIpv4Index;
}
}
 
#if TRINITY_PLATFORM == TRINITY_PLATFORM_WINDOWS
 
#include <boost/dll/shared_library.hpp>
#include <iphlpapi.h>
 
void Trinity::Net::ScanLocalNetworks()
{
 LocalV4Networks.clear();
 LocalV6Networks.clear();
 
 boost::system::error_code dllError;
 boost::dll::shared_library iphlp("Iphlpapi.dll", dllError, boost::dll::load_mode::search_system_folders);
 if (dllError || !iphlp.is_loaded())
 return;
 
 auto getAdaptersAddresses = iphlp.get<decltype(GetAdaptersAddresses)>("GetAdaptersAddresses");
 if (!getAdaptersAddresses)
 return;
 
 ULONG queryFlags = GAA_FLAG_SKIP_UNICAST | GAA_FLAG_SKIP_ANYCAST | GAA_FLAG_SKIP_MULTICAST | GAA_FLAG_SKIP_DNS_SERVER | GAA_FLAG_INCLUDE_PREFIX | GAA_FLAG_SKIP_FRIENDLY_NAME;
 ULONG bufferSize = 0;
 
 if (getAdaptersAddresses(AF_UNSPEC, queryFlags, nullptr, nullptr, &bufferSize) != ERROR_BUFFER_OVERFLOW)
 return;
 
 std::unique_ptr<std::byte[]> addressesBuffer = std::make_unique<std::byte[]>(bufferSize);
 if (getAdaptersAddresses(AF_UNSPEC, queryFlags, nullptr, reinterpret_cast<IP_ADAPTER_ADDRESSES*>(addressesBuffer.get()), &bufferSize) != ERROR_SUCCESS)
 return;
 
 for (IP_ADAPTER_ADDRESSES* itr = reinterpret_cast<IP_ADAPTER_ADDRESSES*>(addressesBuffer.get()); itr; itr = itr->Next)
 {
 if (itr->IfType == IF_TYPE_SOFTWARE_LOOPBACK)
 continue;
 
 if (itr->OperStatus != IfOperStatusUp)
 continue;
 
 for (IP_ADAPTER_PREFIX_XP* prefix = itr->FirstPrefix; prefix; prefix = prefix->Next)
 {
 switch (prefix->Address.lpSockaddr->sa_family)
 {
 case AF_INET:
 {
 SOCKADDR_IN* ipv4raw = reinterpret_cast<SOCKADDR_IN*>(prefix->Address.lpSockaddr);
 boost::asio::ip::address_v4::bytes_type addressBytes;
 std::memcpy(addressBytes.data(), &ipv4raw->sin_addr.s_addr, addressBytes.size());
 boost::asio::ip::address_v4 address = make_address_v4(addressBytes);
 if (address.is_unspecified() || address.is_multicast() || address == boost::asio::ip::address_v4::broadcast())
 continue;
 
 LocalV4Networks.push_back(boost::asio::ip::make_network_v4(address, prefix->PrefixLength));
 break;
 }
 case AF_INET6:
 {
 SOCKADDR_IN6* ipv6raw = reinterpret_cast<SOCKADDR_IN6*>(prefix->Address.lpSockaddr);
 boost::asio::ip::address_v6::bytes_type addressBytes;
 std::memcpy(addressBytes.data(), ipv6raw->sin6_addr.s6_addr, addressBytes.size());
 boost::asio::ip::address_v6 address = make_address_v6(addressBytes, ipv6raw->sin6_scope_id);
 if (address.is_unspecified() || address.is_multicast())
 continue;
 
 LocalV6Networks.push_back(boost::asio::ip::make_network_v6(address, prefix->PrefixLength));
 break;
 }
 default:
 break;
 }
 }
 }
}
 
#else
 
#include <numeric>
#include <ifaddrs.h>
 
void Trinity::Net::ScanLocalNetworks()
{
 LocalV4Networks.clear();
 LocalV6Networks.clear();
 
 ifaddrs* addressesLinkedList = nullptr;
 if (getifaddrs(&addressesLinkedList) == -1)
 return;
 
 for (ifaddrs* itr = addressesLinkedList; itr; itr = itr->ifa_next)
 {
 if (!itr->ifa_addr)
 continue;
 
 switch (itr->ifa_addr->sa_family)
 {
 case AF_INET:
 {
 sockaddr_in* ipv4raw = reinterpret_cast<sockaddr_in*>(itr->ifa_addr);
 boost::asio::ip::address_v4::bytes_type addressBytes;
 std::memcpy(addressBytes.data(), &ipv4raw->sin_addr.s_addr, addressBytes.size());
 boost::asio::ip::address_v4 address = make_address_v4(addressBytes);
 if (address.is_unspecified() || address.is_loopback() || address.is_multicast() || address == boost::asio::ip::address_v4::broadcast())
 continue;
 
 if (sockaddr_in* netmask4raw = reinterpret_cast<sockaddr_in*>(itr->ifa_netmask))
 {
 boost::asio::ip::address_v4::bytes_type netmaskBytes;
 std::memcpy(netmaskBytes.data(), &netmask4raw->sin_addr.s_addr, netmaskBytes.size());
 boost::asio::ip::address_v4 netmask = make_address_v4(netmaskBytes);
 LocalV4Networks.push_back(boost::asio::ip::make_network_v4(address, netmask));
 }
 else
 LocalV4Networks.push_back(boost::asio::ip::make_network_v4(address, 32));
 break;
 }
 case AF_INET6:
 {
 sockaddr_in6* ipv6raw = reinterpret_cast<sockaddr_in6*>(itr->ifa_addr);
 boost::asio::ip::address_v6::bytes_type addressBytes;
 std::memcpy(addressBytes.data(), ipv6raw->sin6_addr.s6_addr, addressBytes.size());
 boost::asio::ip::address_v6 address = make_address_v6(addressBytes, ipv6raw->sin6_scope_id);
 if (address.is_unspecified() || address.is_loopback() || address.is_multicast())
 continue;
 
 if (sockaddr_in6* netmask6raw = reinterpret_cast<sockaddr_in6*>(itr->ifa_netmask))
 {
 int32 prefixLength = 0;
 for (uint8 addressByte : netmask6raw->sin6_addr.s6_addr)
 prefixLength += std::countl_one(addressByte);
 
 LocalV6Networks.push_back(boost::asio::ip::make_network_v6(address, prefixLength));
 }
 else
 LocalV6Networks.push_back(boost::asio::ip::make_network_v6(address, 128));
 break;
 }
 }
 }
 
 freeifaddrs(addressesLinkedList);
}
 
#endif