Add IO::Networking::DNS::ResolveDomain (vmangos#2722)

src/game/Protocol/WorldSocket.cpp

@@ -35,6 +35,7 @@
 #include "Database/DatabaseEnv.h"
 #include "DBCStores.h"
 #include "ace/OS_NS_netdb.h"
+#include "IO/Networking/DNS.h"
 #include "WorldSocketMgr.h"
 
 #if defined( __GNUC__ )
@@ -197,26 +198,22 @@ WorldSocket::HandlerResult WorldSocket::_HandleCompleteReceivedPacket(std::uniqu
     MANGOS_ASSERT(false); // This should never be reached
 }
 
+/// This function will resolve the ip-addresse of the current host
+/// For example if you hostname is called "world.mycoolserver.com" and it points to 123.45.66.7 it will be added to the server list
+/// Also 127.0.0.1 will be added as a fallback
+/// This list is later used to determine if clients try to connect to this server without registering at realmd first
 static std::set<std::string> GetServerAddresses()
 {
     std::set<std::string> addresses;
-    char hostName[MAXHOSTNAMELEN] = {};
+    addresses.insert("127.0.0.1");
 
-    if (ACE_OS::hostname(hostName, MAXHOSTNAMELEN) != -1)
+    std::string myHostname = IO::Networking::DNS::GetOwnHostname();
+    std::vector<IO::Networking::IpAddress> ipAddresses = IO::Networking::DNS::ResolveDomain(myHostname, IO::Networking::IpAddress::Type::IPv4);
+    for (auto const& ipAddress : ipAddresses)
     {
-        if (hostent* hp = ACE_OS::gethostbyname(hostName))
-        {
-            for (int i = 0; hp->h_addr_list[i] != 0; ++i)
-            {
-                in_addr addr;
-                memcpy(&addr, hp->h_addr_list[i], sizeof(in_addr));
-                addresses.insert(ACE_OS::inet_ntoa(addr));
-            }
-        }
+        addresses.insert(ipAddress.toString());
     }
 
-    addresses.insert("127.0.0.1");
-
     return addresses;
 }
 

src/shared/CMakeLists.txt

@@ -110,6 +110,8 @@ set (shared_SRCS
     IO/Context/IoContext_windows.cpp
     IO/SystemErrorToString.h
     IO/SystemErrorToString.cpp
+    IO/Networking/Internal.h
+    IO/Networking/Internal.cpp
     IO/Networking/AsyncServerListener.h
     IO/Networking/AsyncSocket.h
     IO/Networking/NetworkError.h
@@ -119,6 +121,8 @@ set (shared_SRCS
     IO/Networking/Utils.cpp
     IO/Networking/IpAddress.h
     IO/Networking/IpAddress.cpp
+    IO/Networking/DNS.h
+    IO/Networking/DNS.cpp
     IO/Multithreading/CreateThread.h
     IO/Multithreading/CreateThread.cpp
     IO/Timer/impl/windows/AsyncSystemTimer.cpp

src/shared/IO/Networking/DNS.cpp

@@ -0,0 +1,51 @@
+#include "./DNS.h"
+#include "./Internal.h"
+#include "Log.h"
+#include "Errors.h"
+#include "IO/SystemErrorToString.h"
+
+#if defined(WIN32)
+#include <WinSock2.h>
+#include <ws2tcpip.h>
+#endif
+
+std::string IO::Networking::DNS::GetOwnHostname()
+{
+    char hostname[1024];
+    if (::gethostname(hostname, sizeof(hostname)) == -1)
+    {
+        sLog.Out(LogType::LOG_NETWORK, LOG_LVL_ERROR, "IO ERROR: ::gethostname(...): %s", SystemErrorToString(errno).c_str());
+        MANGOS_ASSERT(false);
+    }
+    return hostname;
+}
+
+std::vector<IO::Networking::IpAddress> IO::Networking::DNS::ResolveDomain(std::string const& domainName, IO::Networking::IpAddress::Type type)
+{
+    MANGOS_ASSERT(type == IpAddress::Type::IPv4);
+
+    addrinfo hints = {};
+    hints.ai_family = type == IpAddress::Type::IPv4 ? AF_INET :  AF_INET6;
+    hints.ai_socktype = SOCK_STREAM;
+    hints.ai_protocol = IPPROTO_TCP;
+
+    addrinfo* dnsResult = nullptr;
+    if (::getaddrinfo(domainName.c_str(), nullptr, &hints, &dnsResult) != 0)
+    {
+        sLog.Out(LogType::LOG_NETWORK, LOG_LVL_ERROR, "IO ERROR: ::getaddrinfo(...): %s", SystemErrorToString(errno).c_str());
+        MANGOS_ASSERT(false);
+    }
+
+    std::vector<IO::Networking::IpAddress> list;
+
+    for (addrinfo* ptr = dnsResult; ptr != nullptr; ptr = ptr->ai_next)
+    {
+        sockaddr_in* sockaddr_ipv4 = reinterpret_cast<sockaddr_in*>(ptr->ai_addr);
+        IpAddress ip = IO::Networking::Internal::inet_ntop(&(sockaddr_ipv4->sin_addr));
+        list.emplace_back(ip);
+    }
+
+    freeaddrinfo(dnsResult);
+
+    return list;
+}

src/shared/IO/Networking/DNS.h

@@ -0,0 +1,14 @@
+#ifndef MANGOS_IO_NETWORKING_DNS_H
+#define MANGOS_IO_NETWORKING_DNS_H
+
+#include <vector>
+#include <experimental/vector>
+#include "./IpAddress.h"
+
+namespace IO { namespace Networking { namespace DNS
+{
+    std::string GetOwnHostname();
+    std::vector<IO::Networking::IpAddress> ResolveDomain(std::string const& domainName, IO::Networking::IpAddress::Type type);
+}}} // namespace IO::Networking
+
+#endif // MANGOS_IO_NETWORKING_DNS_H

src/shared/IO/Networking/Internal.cpp

@@ -0,0 +1,23 @@
+#include "Errors.h"
+#include "./Internal.h"
+
+/// Converts a native IN_ADDR to a IO::Networking::IpAddress
+IO::Networking::IpAddress IO::Networking::Internal::inet_ntop(in_addr const* nativeAddress)
+{
+#if defined(WIN32)
+    // We cant use ::inet_ntoa(...) because it's not thread safe. We cant use ::inet_ntop(...) because it's not WinXP compatible, so we have to do it ourselves.
+    int constexpr MAX_IPV4_LENGTH = 16; // "255.255.255.255" = length 15 + 1 for null-terminator
+    char ipv4AddressString[MAX_IPV4_LENGTH];
+    { // impl was taken from ACE, should be universal
+        uint8_t const* p = reinterpret_cast<uint8_t const*>(nativeAddress);
+        snprintf(ipv4AddressString, MAX_IPV4_LENGTH, "%d.%d.%d.%d", p[0], p[1], p[2], p[3]);
+    }
+    auto ipAddress = IO::Networking::IpAddress::TryParseFromString(ipv4AddressString);
+#else
+    char ipv4AddressString[INET_ADDRSTRLEN];
+    ::inet_ntop(AF_INET, nativeAddress, ipv4AddressString, INET_ADDRSTRLEN);
+    auto ipAddress = IO::Networking::IpAddress::TryParseFromString(ipv4AddressString);
+#endif
+    MANGOS_ASSERT(ipAddress.has_value()); // this should never fail, since we got a valid IP from IN_ADDR
+    return ipAddress.value();
+}

src/shared/IO/Networking/Internal.h

@@ -0,0 +1,15 @@
+#ifndef MANGOS_IO_NETWORKING_INTERNAL_H
+#define MANGOS_IO_NETWORKING_INTERNAL_H
+
+#include "./IpAddress.h"
+
+struct in_addr;
+
+namespace IO { namespace Networking { namespace Internal
+{
+    /// Converts a native IN_ADDR to a IO::Networking::IpAddress
+    IO::Networking::IpAddress inet_ntop(in_addr const* nativeAddress);
+
+}}} // IO::Networking::Internal
+
+#endif // MANGOS_IO_NETWORKING_INTERNAL_H

src/shared/IO/Networking/impl/unix/AsyncServerListener_impl.h

@@ -11,6 +11,7 @@
 #include "IO/Context/IoContext.h"
 #include "IO/Networking/SocketDescriptor.h"
 #include "IO/Networking/IpAddress.h"
+#include "IO/Networking/Internal.h"
 #include "IO/SystemErrorToString.h"
 
 #if defined(__linux__)
@@ -109,14 +110,10 @@ void IO::Networking::AsyncServerListener<TClientSocket>::OnNewClientToAcceptAvai
         return;
     }
 
-    char ipv4AddressString[INET_ADDRSTRLEN];
-    ::inet_ntop(AF_INET, &(peerAddress.sin_addr), ipv4AddressString, INET_ADDRSTRLEN);
-    auto peerIpAddress = IO::Networking::IpAddress::TryParseFromString(ipv4AddressString);
+    IO::Networking::IpAddress peerIpAddress = IO::Networking::Internal::inet_ntop(&(peerAddress.sin_addr));
     uint16_t peerPort = ntohs(peerAddress.sin_port);
 
-    MANGOS_ASSERT(peerIpAddress.has_value());
-
-    IO::Networking::IpEndpoint peerEndpoint(peerIpAddress.value(), peerPort);
+    IO::Networking::IpEndpoint peerEndpoint(peerIpAddress, peerPort);
     IO::Networking::SocketDescriptor socketDescriptor{peerEndpoint, nativePeerSocket};
 
     std::shared_ptr<TClientSocket> client = std::make_shared<TClientSocket>(m_ctx, socketDescriptor);

src/shared/IO/Networking/impl/windows/AsyncServerListener_impl.h

@@ -7,6 +7,7 @@
 #include <chrono>
 #include <WinSock2.h>
 #include "Errors.h"
+#include "IO/Networking/Internal.h"
 #include "IO/Context/AsyncIoOperation.h"
 #include "IO/Networking/IpAddress.h"
 #include "IO/Networking/SocketDescriptor.h"
@@ -119,20 +120,11 @@ void IO::Networking::AsyncServerListener<TClientSocket>::StartAcceptOperation()
             return;
         }
 
-        // We cant use ::inet_ntoa(...) because it's not thread safe. We cant use ::inet_ntop(...) because it's not WinXP compatible, so we have to do it ourselves.
-        int constexpr MAX_IPV4_LENGTH = 16; // "255.255.255.255" = length 15 + 1 for null-terminator
-        char ipv4AddressString[MAX_IPV4_LENGTH];
-        { // impl was taken from ACE, should be universal
-            uint8_t const* const p = reinterpret_cast<uint8_t const*>(&addrBuffer->peerAddress.sin_addr);
-            snprintf(ipv4AddressString, MAX_IPV4_LENGTH, "%d.%d.%d.%d", p[0], p[1], p[2], p[3]);
-        }
-        auto peerIpAddress = IO::Networking::IpAddress::TryParseFromString(ipv4AddressString);
+        IO::Networking::IpAddress peerIpAddress = IO::Networking::Internal::inet_ntop(&(addrBuffer->peerAddress.sin_addr));
         uint16_t peerPort = ntohs(addrBuffer->peerAddress.sin_port);
-
         delete addrBuffer;
-        MANGOS_ASSERT(peerIpAddress.has_value());
 
-        IO::Networking::IpEndpoint peerEndpoint(peerIpAddress.value(), peerPort);
+        IO::Networking::IpEndpoint peerEndpoint(peerIpAddress, peerPort);
         IO::Networking::SocketDescriptor socketDescriptor{ peerEndpoint, nativePeerSocket };
 
         std::shared_ptr<TClientSocket> client = std::make_shared<TClientSocket>(m_ctx, socketDescriptor);