Resolve IP addresses without touching DNS layer

0blu · Sep 22, 2024 · c1c4927 · c1c4927
1 parent 89a399f
commit c1c4927
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Showing 3 changed files with 42 additions and 8 deletions.
diff --git a/src/shared/IO/Networking/DNS.cpp b/src/shared/IO/Networking/DNS.cpp
@@ -25,8 +25,18 @@ std::string IO::Networking::DNS::GetOwnHostname()
 
 std::vector<IO::Networking::IpAddress> IO::Networking::DNS::ResolveDomain(std::string const& domainName, IO::Networking::IpAddress::Type type)
 {
-    MANGOS_ASSERT(type == IpAddress::Type::IPv4);
+    MANGOS_ASSERT(type == IpAddress::Type::IPv4); // TODO: this function is only tested with IPv4. `inet_ntop` will fail
 
+    // Check if we can parse the domain as an IP
+    nonstd::optional<IpAddress> maybeIp = IpAddress::TryParseFromString(domainName);
+    if (maybeIp)
+    {
+        IpAddress const& ip = maybeIp.value();
+        MANGOS_ASSERT(ip.GetType() == type);
+        return { ip }; // The "domain" can be directly parsed as an IP
+    }
+
+    // try to resolve the domain
     addrinfo hints = {};
     hints.ai_family = type == IpAddress::Type::IPv4 ? AF_INET :  AF_INET6;
     hints.ai_socktype = SOCK_STREAM;
@@ -35,17 +45,37 @@ std::vector<IO::Networking::IpAddress> IO::Networking::DNS::ResolveDomain(std::s
     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);
+        sLog.Out(LogType::LOG_NETWORK, LOG_LVL_ERROR, "IO ERROR: ::getaddrinfo(...): %s", SystemErrorToString(
+#if defined(WIN32)
+        ::WSAGetLastError()
+#else
+        errno
+#endif
+        ).c_str());
+        return {}; // error occurred, empty return
     }
 
-    std::vector<IO::Networking::IpAddress> list;
+    std::vector<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);
+        if (ptr->ai_family == AF_INET)
+        {
+            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);
+        }
+        else if (ptr->ai_family == AF_INET6)
+        {
+            // TODO: Add inet_ntop for IPv6
+            //sockaddr_in6* sockaddr_ipv6 = reinterpret_cast<sockaddr_in6*>(ptr->ai_addr);
+            //IpAddress ip = IO::Networking::Internal::inet_ntop(&(sockaddr_ipv6->sin_addr));
+            //list.emplace_back(ip);
+        }
+        else
+        {
+            std::unexpected();
+        }
     }
 
     freeaddrinfo(dnsResult);

diff --git a/src/shared/IO/Networking/DNS.h b/src/shared/IO/Networking/DNS.h
@@ -7,6 +7,9 @@
 namespace IO { namespace Networking { namespace DNS
 {
     std::string GetOwnHostname();
+
+    /// Will also work with IP addresses without touching the DNS layer
+    /// \warning Will return an empty list if unable to resolve the domain
     std::vector<IO::Networking::IpAddress> ResolveDomain(std::string const& domainName, IO::Networking::IpAddress::Type type);
 }}} // namespace IO::Networking
 

diff --git a/src/shared/IO/Networking/Internal.h b/src/shared/IO/Networking/Internal.h
@@ -10,7 +10,8 @@ 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);
-    // Converts a `IO::Networking::IpAddress` to a native `IN_ADDR`
+
+    /// Converts a `IO::Networking::IpAddress` to a native `IN_ADDR`
     void inet_pton(IO::Networking::IpAddress const& ipAddress, in_addr* out_dest);
 
     /// Closes a socket