Merge pull request #10690 from schthack/BBA-tapless

BBA: Added BuiltIn device that allow BBA emulation without the need o…

Source/Core/Common/Network.cpp

@@ -5,6 +5,7 @@
 
 #include <algorithm>
 #include <string_view>
+#include <vector>
 
 #ifndef _WIN32
 #include <netinet/in.h>
@@ -16,6 +17,7 @@
 
 #include <fmt/format.h>
 
+#include "Common/BitUtils.h"
 #include "Common/Random.h"
 #include "Common/StringUtil.h"
 
@@ -113,6 +115,11 @@ u16 IPv4Header::Size() const
   return static_cast<u16>(SIZE);
 }
 
+u8 IPv4Header::DefinedSize() const
+{
+  return (version_ihl & 0xf) * 4;
+}
+
 TCPHeader::TCPHeader() = default;
 
 TCPHeader::TCPHeader(const sockaddr_in& from, const sockaddr_in& to, u32 seq, const u8* data,
@@ -141,6 +148,23 @@ TCPHeader::TCPHeader(const sockaddr_in& from, const sockaddr_in& to, u32 seq, co
   checksum = htons(static_cast<u16>(tcp_checksum));
 }
 
+TCPHeader::TCPHeader(const sockaddr_in& from, const sockaddr_in& to, u32 seq, u32 ack, u16 flags)
+{
+  source_port = from.sin_port;
+  destination_port = to.sin_port;
+  sequence_number = htonl(seq);
+  acknowledgement_number = htonl(ack);
+  properties = htons(flags);
+
+  window_size = 0x7c;
+  checksum = 0;
+}
+
+u8 TCPHeader::GetHeaderSize() const
+{
+  return (ntohs(properties) & 0xf000) >> 10;
+}
+
 u16 TCPHeader::Size() const
 {
   return static_cast<u16>(SIZE);
@@ -170,6 +194,92 @@ u8 UDPHeader::IPProto() const
   return static_cast<u8>(IPPROTO_UDP);
 }
 
+ARPHeader::ARPHeader() = default;
+
+ARPHeader::ARPHeader(u32 from_ip, const MACAddress& from_mac, u32 to_ip, const MACAddress& to_mac)
+{
+  hardware_type = htons(BBA_HARDWARE_TYPE);
+  protocol_type = IPV4_HEADER_TYPE;
+  hardware_size = MAC_ADDRESS_SIZE;
+  protocol_size = IPV4_ADDR_LEN;
+  opcode = 0x200;
+  sender_ip = from_ip;
+  target_ip = to_ip;
+  targer_address = to_mac;
+  sender_address = from_mac;
+}
+
+u16 ARPHeader::Size() const
+{
+  return static_cast<u16>(SIZE);
+}
+
+DHCPBody::DHCPBody() = default;
+
+DHCPBody::DHCPBody(u32 transaction, const MACAddress& client_address, u32 new_ip, u32 serv_ip)
+{
+  transaction_id = transaction;
+  message_type = DHCPConst::MESSAGE_REPLY;
+  hardware_type = BBA_HARDWARE_TYPE;
+  hardware_addr = MAC_ADDRESS_SIZE;
+  client_mac = client_address;
+  your_ip = new_ip;
+  server_ip = serv_ip;
+}
+
+DHCPPacket::DHCPPacket() = default;
+
+DHCPPacket::DHCPPacket(const std::vector<u8>& data)
+{
+  if (data.size() < DHCPBody::SIZE)
+    return;
+  body = Common::BitCastPtr<DHCPBody>(data.data());
+  std::size_t offset = DHCPBody::SIZE;
+
+  while (offset < data.size() - 1)
+  {
+    const u8 fnc = data[offset];
+    if (fnc == 0)
+    {
+      ++offset;
+      continue;
+    }
+    if (fnc == 255)
+      break;
+    const u8 len = data[offset + 1];
+    const auto opt_begin = data.begin() + offset;
+    offset += 2 + len;
+    if (offset > data.size())
+      break;
+    const auto opt_end = data.begin() + offset;
+    options.emplace_back(opt_begin, opt_end);
+  }
+}
+
+void DHCPPacket::AddOption(u8 fnc, const std::vector<u8>& params)
+{
+  if (params.size() > 255)
+    return;
+  std::vector<u8> opt = {fnc, u8(params.size())};
+  opt.insert(opt.end(), params.begin(), params.end());
+  options.emplace_back(std::move(opt));
+}
+
+std::vector<u8> DHCPPacket::Build() const
+{
+  const u8* body_ptr = reinterpret_cast<const u8*>(&body);
+  std::vector<u8> result(body_ptr, body_ptr + DHCPBody::SIZE);
+
+  for (auto& opt : options)
+  {
+    result.insert(result.end(), opt.begin(), opt.end());
+  }
+  const std::vector<u8> no_option = {255, 0, 0, 0};
+  result.insert(result.end(), no_option.begin(), no_option.end());
+
+  return result;
+}
+
 // Compute the network checksum with a 32-bit accumulator using the
 // "Normal" order, see RFC 1071 for more details.
 u16 ComputeNetworkChecksum(const void* data, u16 length, u32 initial_value)
@@ -187,6 +297,257 @@ u16 ComputeNetworkChecksum(const void* data, u16 length, u32 initial_value)
   return ~static_cast<u16>(checksum);
 }
 
+// Compute the TCP checksum with its pseudo header
+u16 ComputeTCPNetworkChecksum(const IPAddress& from, const IPAddress& to, const void* data,
+                              u16 length, u8 protocol)
+{
+  const u32 source_addr = ntohl(Common::BitCast<u32>(from));
+  const u32 destination_addr = ntohl(Common::BitCast<u32>(to));
+  const u32 initial_value = (source_addr >> 16) + (source_addr & 0xFFFF) +
+                            (destination_addr >> 16) + (destination_addr & 0xFFFF) + protocol +
+                            length;
+  const u32 tcp_checksum = ComputeNetworkChecksum(data, length, initial_value);
+  return htons(static_cast<u16>(tcp_checksum));
+}
+
+ARPPacket::ARPPacket() = default;
+
+u16 ARPPacket::Size() const
+{
+  return static_cast<u16>(SIZE);
+}
+
+ARPPacket::ARPPacket(const MACAddress& destination, const MACAddress& source)
+{
+  eth_header.destination = destination;
+  eth_header.source = source;
+  eth_header.ethertype = htons(ARP_ETHERTYPE);
+}
+
+std::vector<u8> ARPPacket::Build() const
+{
+  std::vector<u8> result;
+  result.reserve(EthernetHeader::SIZE + ARPHeader::SIZE);
+  const u8* eth_ptr = reinterpret_cast<const u8*>(&eth_header);
+  result.insert(result.end(), eth_ptr, eth_ptr + EthernetHeader::SIZE);
+  const u8* arp_ptr = reinterpret_cast<const u8*>(&arp_header);
+  result.insert(result.end(), arp_ptr, arp_ptr + ARPHeader::SIZE);
+  return result;
+}
+
+TCPPacket::TCPPacket() = default;
+
+TCPPacket::TCPPacket(const MACAddress& destination, const MACAddress& source)
+{
+  eth_header.destination = destination;
+  eth_header.source = source;
+  eth_header.ethertype = htons(IPV4_ETHERTYPE);
+}
+
+TCPPacket::TCPPacket(const MACAddress& destination, const MACAddress& source,
+                     const sockaddr_in& from, const sockaddr_in& to, u32 seq, u32 ack, u16 flags)
+{
+  eth_header.destination = destination;
+  eth_header.source = source;
+  eth_header.ethertype = htons(IPV4_ETHERTYPE);
+
+  ip_header = Common::IPv4Header(Common::TCPHeader::SIZE, IPPROTO_TCP, from, to);
+  tcp_header = Common::TCPHeader(from, to, seq, ack, flags);
+}
+
+std::vector<u8> TCPPacket::Build()
+{
+  std::vector<u8> result;
+  result.reserve(Size());
+
+  // recalc size
+  ip_header.total_len = htons(static_cast<u16>(IPv4Header::SIZE + ipv4_options.size() +
+                                               TCPHeader::SIZE + tcp_options.size() + data.size()));
+
+  // copy data
+  const u8* eth_ptr = reinterpret_cast<const u8*>(&eth_header);
+  result.insert(result.end(), eth_ptr, eth_ptr + EthernetHeader::SIZE);
+  const u8* ip_ptr = reinterpret_cast<const u8*>(&ip_header);
+  result.insert(result.end(), ip_ptr, ip_ptr + IPv4Header::SIZE);
+  std::size_t offset = EthernetHeader::SIZE + IPv4Header::SIZE;
+  if (ipv4_options.size() > 0)
+  {
+    result.insert(result.end(), ipv4_options.begin(), ipv4_options.end());
+    offset += ipv4_options.size();
+  }
+  tcp_header.checksum = 0;
+  const u16 props = (ntohs(tcp_header.properties) & 0xfff) |
+                    (static_cast<u16>((tcp_options.size() + TCPHeader::SIZE) & 0x3c) << 10);
+  tcp_header.properties = htons(props);
+  const u8* tcp_ptr = reinterpret_cast<const u8*>(&tcp_header);
+  result.insert(result.end(), tcp_ptr, tcp_ptr + TCPHeader::SIZE);
+  const std::size_t tcp_offset = offset;
+  offset += TCPHeader::SIZE;
+  if (tcp_options.size() > 0)
+  {
+    result.insert(result.end(), tcp_options.begin(), tcp_options.end());
+    offset += tcp_options.size();
+  }
+  if (data.size() > 0)
+  {
+    result.insert(result.end(), data.begin(), data.end());
+  }
+  tcp_header.checksum = ComputeTCPNetworkChecksum(
+      ip_header.source_addr, ip_header.destination_addr, &result[tcp_offset],
+      static_cast<u16>(result.size() - tcp_offset), IPPROTO_TCP);
+  std::copy(tcp_ptr, tcp_ptr + TCPHeader::SIZE, result.begin() + tcp_offset);
+  return result;
+}
+
+u16 TCPPacket::Size() const
+{
+  return static_cast<u16>(MIN_SIZE + data.size() + ipv4_options.size() + tcp_options.size());
+}
+
+UDPPacket::UDPPacket() = default;
+
+UDPPacket::UDPPacket(const MACAddress& destination, const MACAddress& source)
+{
+  eth_header.destination = destination;
+  eth_header.source = source;
+  eth_header.ethertype = htons(IPV4_ETHERTYPE);
+}
+
+UDPPacket::UDPPacket(const MACAddress& destination, const MACAddress& source,
+                     const sockaddr_in& from, const sockaddr_in& to, const std::vector<u8>& payload)
+{
+  eth_header.destination = destination;
+  eth_header.source = source;
+  eth_header.ethertype = htons(IPV4_ETHERTYPE);
+
+  ip_header = Common::IPv4Header(static_cast<u16>(payload.size() + Common::UDPHeader::SIZE),
+                                 IPPROTO_UDP, from, to);
+  udp_header = Common::UDPHeader(from, to, static_cast<u16>(payload.size()));
+  data = payload;
+}
+
+std::vector<u8> UDPPacket::Build()
+{
+  std::vector<u8> result;
+  result.reserve(Size());
+
+  // recalc size
+  ip_header.total_len = htons(
+      static_cast<u16>(IPv4Header::SIZE + ipv4_options.size() + UDPHeader::SIZE + data.size()));
+  udp_header.length = htons(static_cast<u16>(UDPHeader::SIZE + data.size()));
+
+  // copy data
+  const u8* eth_ptr = reinterpret_cast<const u8*>(&eth_header);
+  result.insert(result.end(), eth_ptr, eth_ptr + EthernetHeader::SIZE);
+  const u8* ip_ptr = reinterpret_cast<const u8*>(&ip_header);
+  result.insert(result.end(), ip_ptr, ip_ptr + IPv4Header::SIZE);
+  std::size_t offset = EthernetHeader::SIZE + IPv4Header::SIZE;
+  if (ipv4_options.size() > 0)
+  {
+    result.insert(result.end(), ipv4_options.begin(), ipv4_options.end());
+    offset += ipv4_options.size();
+  }
+  udp_header.checksum = 0;
+  const u8* udp_ptr = reinterpret_cast<const u8*>(&udp_header);
+  result.insert(result.end(), udp_ptr, udp_ptr + UDPHeader::SIZE);
+  const std::size_t udp_offset = offset;
+  offset += UDPHeader::SIZE;
+  if (data.size() > 0)
+  {
+    result.insert(result.end(), data.begin(), data.end());
+  }
+  udp_header.checksum = ComputeTCPNetworkChecksum(
+      ip_header.source_addr, ip_header.destination_addr, &result[udp_offset],
+      static_cast<u16>(result.size() - udp_offset), IPPROTO_UDP);
+  std::copy(udp_ptr, udp_ptr + UDPHeader::SIZE, result.begin() + udp_offset);
+
+  return result;
+}
+
+u16 UDPPacket::Size() const
+{
+  return static_cast<u16>(MIN_SIZE + data.size() + ipv4_options.size());
+}
+
+PacketView::PacketView(const u8* ptr, std::size_t size) : m_ptr(ptr), m_size(size)
+{
+}
+
+std::optional<u16> PacketView::GetEtherType() const
+{
+  if (m_size < EthernetHeader::SIZE)
+    return std::nullopt;
+  const std::size_t offset = offsetof(EthernetHeader, ethertype);
+  return ntohs(Common::BitCastPtr<u16>(m_ptr + offset));
+}
+
+std::optional<ARPPacket> PacketView::GetARPPacket() const
+{
+  if (m_size < ARPPacket::SIZE)
+    return std::nullopt;
+  return Common::BitCastPtr<ARPPacket>(m_ptr);
+}
+
+std::optional<u8> PacketView::GetIPProto() const
+{
+  if (m_size < EthernetHeader::SIZE + IPv4Header::SIZE)
+    return std::nullopt;
+  return m_ptr[EthernetHeader::SIZE + offsetof(IPv4Header, protocol)];
+}
+
+std::optional<TCPPacket> PacketView::GetTCPPacket() const
+{
+  if (m_size < TCPPacket::MIN_SIZE)
+    return std::nullopt;
+  TCPPacket result;
+  result.eth_header = Common::BitCastPtr<EthernetHeader>(m_ptr);
+  result.ip_header = Common::BitCastPtr<IPv4Header>(m_ptr + EthernetHeader::SIZE);
+  const u16 offset = result.ip_header.DefinedSize() + EthernetHeader::SIZE;
+  if (m_size < offset + TCPHeader::SIZE)
+    return std::nullopt;
+  result.ipv4_options =
+      std::vector<u8>(m_ptr + EthernetHeader::SIZE + IPv4Header::SIZE, m_ptr + offset);
+  result.tcp_header = Common::BitCastPtr<TCPHeader>(m_ptr + offset);
+  const u16 data_offset = result.tcp_header.GetHeaderSize() + offset;
+
+  const u16 total_len = ntohs(result.ip_header.total_len);
+  const std::size_t end = EthernetHeader::SIZE + total_len;
+
+  if (m_size < end || end < data_offset)
+    return std::nullopt;
+
+  result.tcp_options = std::vector<u8>(m_ptr + offset + TCPHeader::SIZE, m_ptr + data_offset);
+  result.data = std::vector<u8>(m_ptr + data_offset, m_ptr + end);
+
+  return result;
+}
+
+std::optional<UDPPacket> PacketView::GetUDPPacket() const
+{
+  if (m_size < UDPPacket::MIN_SIZE)
+    return std::nullopt;
+  UDPPacket result;
+  result.eth_header = Common::BitCastPtr<EthernetHeader>(m_ptr);
+  result.ip_header = Common::BitCastPtr<IPv4Header>(m_ptr + EthernetHeader::SIZE);
+  const u16 offset = result.ip_header.DefinedSize() + EthernetHeader::SIZE;
+  if (m_size < offset + UDPHeader::SIZE)
+    return std::nullopt;
+  result.ipv4_options =
+      std::vector<u8>(m_ptr + EthernetHeader::SIZE + IPv4Header::SIZE, m_ptr + offset);
+  result.udp_header = Common::BitCastPtr<UDPHeader>(m_ptr + offset);
+  const u16 data_offset = UDPHeader::SIZE + offset;
+
+  const u16 total_len = ntohs(result.udp_header.length);
+  const std::size_t end = offset + total_len;
+
+  if (m_size < end || end < data_offset)
+    return std::nullopt;
+
+  result.data = std::vector<u8>(m_ptr + data_offset, m_ptr + end);
+
+  return result;
+}
+
 NetworkErrorState SaveNetworkErrorState()
 {
   return {

Source/Core/Common/Network.h

@@ -7,6 +7,7 @@
 #include <optional>
 #include <string>
 #include <string_view>
+#include <vector>
 
 #include "Common/CommonTypes.h"
 
@@ -22,11 +23,25 @@ enum class MACConsumer
 
 enum
 {
-  MAC_ADDRESS_SIZE = 6
+  BBA_HARDWARE_TYPE = 1,
+  MAC_ADDRESS_SIZE = 6,
+  IPV4_HEADER_TYPE = 8
+};
+
+enum DHCPConst
+{
+  MESSAGE_QUERY = 1,
+  MESSAGE_REPLY = 2
 };
 
 using MACAddress = std::array<u8, MAC_ADDRESS_SIZE>;
 constexpr std::size_t IPV4_ADDR_LEN = 4;
+using IPAddress = std::array<u8, IPV4_ADDR_LEN>;
+constexpr IPAddress IP_ADDR_ANY = {0, 0, 0, 0};
+constexpr IPAddress IP_ADDR_BROADCAST = {255, 255, 255, 255};
+constexpr IPAddress IP_ADDR_SSDP = {239, 255, 255, 250};
+constexpr u16 IPV4_ETHERTYPE = 0x800;
+constexpr u16 ARP_ETHERTYPE = 0x806;
 
 struct EthernetHeader
 {
@@ -47,6 +62,7 @@ struct IPv4Header
   IPv4Header();
   IPv4Header(u16 data_size, u8 ip_proto, const sockaddr_in& from, const sockaddr_in& to);
   u16 Size() const;
+  u8 DefinedSize() const;
 
   static constexpr std::size_t SIZE = 20;
 
@@ -58,8 +74,8 @@ struct IPv4Header
   u8 ttl = 0;
   u8 protocol = 0;
   u16 header_checksum = 0;
-  std::array<u8, IPV4_ADDR_LEN> source_addr{};
+  IPAddress source_addr{};
-  std::array<u8, IPV4_ADDR_LEN> destination_addr{};
+  IPAddress destination_addr{};
 };
 static_assert(sizeof(IPv4Header) == IPv4Header::SIZE);
 
@@ -67,6 +83,8 @@ struct TCPHeader
 {
   TCPHeader();
   TCPHeader(const sockaddr_in& from, const sockaddr_in& to, u32 seq, const u8* data, u16 length);
+  TCPHeader(const sockaddr_in& from, const sockaddr_in& to, u32 seq, u32 ack, u16 flags);
+  u8 GetHeaderSize() const;
   u16 Size() const;
   u8 IPProto() const;
 
@@ -99,6 +117,134 @@ struct UDPHeader
 };
 static_assert(sizeof(UDPHeader) == UDPHeader::SIZE);
 
+#pragma pack(push, 1)
+struct ARPHeader
+{
+  ARPHeader();
+  ARPHeader(u32 from_ip, const MACAddress& from_mac, u32 to_ip, const MACAddress& to_mac);
+  u16 Size() const;
+
+  static constexpr std::size_t SIZE = 28;
+
+  u16 hardware_type = 0;
+  u16 protocol_type = 0;
+  u8 hardware_size = 0;
+  u8 protocol_size = 0;
+  u16 opcode = 0;
+  MACAddress sender_address{};
+  u32 sender_ip = 0;
+  MACAddress targer_address{};
+  u32 target_ip = 0;
+};
+static_assert(sizeof(ARPHeader) == ARPHeader::SIZE);
+#pragma pack(pop)
+
+struct DHCPBody
+{
+  DHCPBody();
+  DHCPBody(u32 transaction, const MACAddress& client_address, u32 new_ip, u32 serv_ip);
+  static constexpr std::size_t SIZE = 240;
+  u8 message_type = 0;
+  u8 hardware_type = 0;
+  u8 hardware_addr = 0;
+  u8 hops = 0;
+  u32 transaction_id = 0;
+  u16 seconds = 0;
+  u16 boot_flag = 0;
+  u32 client_ip = 0;
+  u32 your_ip = 0;
+  u32 server_ip = 0;
+  u32 relay_ip = 0;
+  MACAddress client_mac{};
+  unsigned char padding[10]{};
+  unsigned char hostname[0x40]{};
+  unsigned char boot_file[0x80]{};
+  u8 magic_cookie[4] = {0x63, 0x82, 0x53, 0x63};
+};
+static_assert(sizeof(DHCPBody) == DHCPBody::SIZE);
+
+struct DHCPPacket
+{
+  DHCPPacket();
+  DHCPPacket(const std::vector<u8>& data);
+  void AddOption(u8 fnc, const std::vector<u8>& params);
+  std::vector<u8> Build() const;
+
+  DHCPBody body;
+  std::vector<std::vector<u8>> options;
+};
+
+// The compiler might add 2 bytes after EthernetHeader to enforce 16-bytes alignment
+#pragma pack(push, 1)
+struct ARPPacket
+{
+  ARPPacket();
+  ARPPacket(const MACAddress& destination, const MACAddress& source);
+  std::vector<u8> Build() const;
+  u16 Size() const;
+
+  EthernetHeader eth_header;
+  ARPHeader arp_header;
+
+  static constexpr std::size_t SIZE = EthernetHeader::SIZE + ARPHeader::SIZE;
+};
+static_assert(sizeof(ARPPacket) == ARPPacket::SIZE);
+#pragma pack(pop)
+
+struct TCPPacket
+{
+  TCPPacket();
+  TCPPacket(const MACAddress& destination, const MACAddress& source);
+  TCPPacket(const MACAddress& destination, const MACAddress& source, const sockaddr_in& from,
+            const sockaddr_in& to, u32 seq, u32 ack, u16 flags);
+  std::vector<u8> Build();
+  u16 Size() const;
+
+  EthernetHeader eth_header;
+  IPv4Header ip_header;
+  TCPHeader tcp_header;
+  std::vector<u8> ipv4_options;
+  std::vector<u8> tcp_options;
+  std::vector<u8> data;
+
+  static constexpr std::size_t MIN_SIZE = EthernetHeader::SIZE + IPv4Header::SIZE + TCPHeader::SIZE;
+};
+
+struct UDPPacket
+{
+  UDPPacket();
+  UDPPacket(const MACAddress& destination, const MACAddress& source);
+  UDPPacket(const MACAddress& destination, const MACAddress& source, const sockaddr_in& from,
+            const sockaddr_in& to, const std::vector<u8>& payload);
+  std::vector<u8> Build();
+  u16 Size() const;
+
+  EthernetHeader eth_header;
+  IPv4Header ip_header;
+  UDPHeader udp_header;
+
+  std::vector<u8> ipv4_options;
+  std::vector<u8> data;
+
+  static constexpr std::size_t MIN_SIZE = EthernetHeader::SIZE + IPv4Header::SIZE + UDPHeader::SIZE;
+};
+
+class PacketView
+{
+public:
+  PacketView(const u8* ptr, std::size_t size);
+
+  std::optional<u16> GetEtherType() const;
+  std::optional<ARPPacket> GetARPPacket() const;
+  std::optional<u8> GetIPProto() const;
+  std::optional<TCPPacket> GetTCPPacket() const;
+  std::optional<UDPPacket> GetUDPPacket() const;
+
+private:
+  const u8* m_ptr;
+  std::size_t m_size;
+};
+
 struct NetworkErrorState
 {
   int error;
@@ -111,6 +257,8 @@ MACAddress GenerateMacAddress(MACConsumer type);
 std::string MacAddressToString(const MACAddress& mac);
 std::optional<MACAddress> StringToMacAddress(std::string_view mac_string);
 u16 ComputeNetworkChecksum(const void* data, u16 length, u32 initial_value = 0);
+u16 ComputeTCPNetworkChecksum(const IPAddress& from, const IPAddress& to, const void* data,
+                              u16 length, u8 protocol);
 NetworkErrorState SaveNetworkErrorState();
 void RestoreNetworkErrorState(const NetworkErrorState& state);
 }  // namespace Common

Source/Core/Core/CMakeLists.txt

@@ -647,6 +647,8 @@ if(WIN32)
     HW/EXI/BBA/TAP_Win32.cpp
     HW/EXI/BBA/TAP_Win32.h
     HW/EXI/BBA/XLINK_KAI_BBA.cpp
+    HW/EXI/BBA/BuiltIn.cpp
+    HW/EXI/BBA/BuiltIn.h
     HW/WiimoteReal/IOWin.cpp
     HW/WiimoteReal/IOWin.h
   )
@@ -662,12 +664,16 @@ elseif(APPLE)
     HW/EXI/BBA/TAP_Apple.cpp
     HW/EXI/BBA/TAPServer_Apple.cpp
     HW/EXI/BBA/XLINK_KAI_BBA.cpp
+    HW/EXI/BBA/BuiltIn.cpp
+    HW/EXI/BBA/BuiltIn.h
   )
   target_link_libraries(core PUBLIC ${IOB_LIBRARY})
 elseif(UNIX)
   target_sources(core PRIVATE
     HW/EXI/BBA/TAP_Unix.cpp
     HW/EXI/BBA/XLINK_KAI_BBA.cpp
+    HW/EXI/BBA/BuiltIn.cpp
+    HW/EXI/BBA/BuiltIn.h
   )
   if(ANDROID)
     target_sources(core PRIVATE

Source/Core/Core/Config/MainSettings.cpp

@@ -116,6 +116,11 @@ const Info<std::string> MAIN_BBA_MAC{{System::Main, "Core", "BBA_MAC"}, ""};
 const Info<std::string> MAIN_BBA_XLINK_IP{{System::Main, "Core", "BBA_XLINK_IP"}, "127.0.0.1"};
 const Info<bool> MAIN_BBA_XLINK_CHAT_OSD{{System::Main, "Core", "BBA_XLINK_CHAT_OSD"}, true};
 
+// Schthack PSO Server - https://schtserv.com/
+const Info<std::string> MAIN_BBA_BUILTIN_DNS{{System::Main, "Core", "BBA_BUILTIN_DNS"},
+                                             "149.56.167.128"};
+const Info<std::string> MAIN_BBA_BUILTIN_IP{{System::Main, "Core", "BBA_BUILTIN_IP"}, ""};
+
 const Info<SerialInterface::SIDevices>& GetInfoForSIDevice(int channel)
 {
   static const std::array<const Info<SerialInterface::SIDevices>, 4> infos{

Source/Core/Core/Config/MainSettings.h

@@ -86,6 +86,8 @@ const Info<ExpansionInterface::EXIDeviceType>& GetInfoForEXIDevice(ExpansionInte
 extern const Info<std::string> MAIN_BBA_MAC;
 extern const Info<std::string> MAIN_BBA_XLINK_IP;
 extern const Info<bool> MAIN_BBA_XLINK_CHAT_OSD;
+extern const Info<std::string> MAIN_BBA_BUILTIN_DNS;
+extern const Info<std::string> MAIN_BBA_BUILTIN_IP;
 const Info<SerialInterface::SIDevices>& GetInfoForSIDevice(int channel);
 const Info<bool>& GetInfoForAdapterRumble(int channel);
 const Info<bool>& GetInfoForSimulateKonga(int channel);

Source/Core/Core/ConfigLoaders/IsSettingSaveable.cpp

@@ -81,6 +81,8 @@ bool IsSettingSaveable(const Config::Location& config_location)
       &Config::MAIN_AGP_CART_B_PATH.GetLocation(),
       &Config::MAIN_BBA_MAC.GetLocation(),
       &Config::MAIN_BBA_XLINK_IP.GetLocation(),
+      &Config::MAIN_BBA_BUILTIN_DNS.GetLocation(),
+      &Config::MAIN_BBA_BUILTIN_IP.GetLocation(),
       &Config::MAIN_BBA_XLINK_CHAT_OSD.GetLocation(),
       &Config::MAIN_OVERRIDE_REGION_SETTINGS.GetLocation(),
       &Config::MAIN_CUSTOM_RTC_ENABLE.GetLocation(),

Source/Core/Core/HW/EXI/BBA/BuiltIn.cpp

@@ -0,0 +1,687 @@
+// Copyright 2022 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <SFML/Network.hpp>
+
+#include "Common/BitUtils.h"
+#include "Common/Logging/Log.h"
+#include "Common/MsgHandler.h"
+#include "Core/HW/EXI/BBA/BuiltIn.h"
+#include "Core/HW/EXI/EXI_Device.h"
+#include "Core/HW/EXI/EXI_DeviceEthernet.h"
+
+namespace ExpansionInterface
+{
+u64 GetTickCountStd()
+{
+  using namespace std::chrono;
+  return duration_cast<milliseconds>(steady_clock::now().time_since_epoch()).count();
+}
+
+bool CEXIETHERNET::BuiltInBBAInterface::Activate()
+{
+  if (IsActivated())
+    return true;
+
+  m_active = true;
+  for (auto& buf : m_queue_data)
+    buf.reserve(2048);
+  m_fake_mac = Common::GenerateMacAddress(Common::MACConsumer::BBA);
+
+  // Workaround to get the host IP (might not be accurate)
+  const u32 ip = m_local_ip.empty() ? sf::IpAddress::getLocalAddress().toInteger() :
+                                      sf::IpAddress(m_local_ip).toInteger();
+  m_current_ip = htonl(ip);
+  m_router_ip = (m_current_ip & 0xFFFFFF) | 0x01000000;
+
+  // clear all ref
+  for (auto& ref : network_ref)
+  {
+    ref.ip = 0;
+  }
+
+  return RecvInit();
+}
+
+void CEXIETHERNET::BuiltInBBAInterface::Deactivate()
+{
+  // Is the BBA Active? If not skip shutdown
+  if (!IsActivated())
+    return;
+  // Signal read thread to exit.
+  m_read_enabled.Clear();
+  m_read_thread_shutdown.Set();
+  m_active = false;
+
+  // kill all active socket
+  for (auto& ref : network_ref)
+  {
+    if (ref.ip != 0)
+    {
+      ref.type == IPPROTO_TCP ? ref.tcp_socket.disconnect() : ref.udp_socket.unbind();
+    }
+    ref.ip = 0;
+  }
+
+  // Wait for read thread to exit.
+  if (m_read_thread.joinable())
+    m_read_thread.join();
+}
+
+bool CEXIETHERNET::BuiltInBBAInterface::IsActivated()
+{
+  return m_active;
+}
+
+void CEXIETHERNET::BuiltInBBAInterface::WriteToQueue(const std::vector<u8>& data)
+{
+  m_queue_data[m_queue_write] = data;
+  const u8 next_write_index = (m_queue_write + 1) & 15;
+  if (next_write_index != m_queue_read)
+    m_queue_write = next_write_index;
+}
+
+void CEXIETHERNET::BuiltInBBAInterface::HandleARP(const Common::ARPPacket& packet)
+{
+  const auto& [hwdata, arpdata] = packet;
+  const Common::MACAddress bba_mac =
+      Common::BitCastPtr<Common::MACAddress>(&m_eth_ref->mBbaMem[BBA_NAFR_PAR0]);
+  Common::ARPPacket response(bba_mac, m_fake_mac);
+
+  if (arpdata.target_ip == m_current_ip)
+  {
+    // game asked for himself, reply with his mac address
+    response.arp_header = Common::ARPHeader(arpdata.target_ip, bba_mac, m_current_ip, bba_mac);
+  }
+  else
+  {
+    response.arp_header = Common::ARPHeader(arpdata.target_ip, m_fake_mac, m_current_ip, bba_mac);
+  }
+
+  WriteToQueue(response.Build());
+}
+
+void CEXIETHERNET::BuiltInBBAInterface::HandleDHCP(const Common::UDPPacket& packet)
+{
+  const auto& [hwdata, ip, udp_header, ip_options, data] = packet;
+  const Common::DHCPPacket dhcp(packet.data);
+  const Common::DHCPBody& request = dhcp.body;
+  sockaddr_in from;
+  sockaddr_in to;
+  from.sin_addr.s_addr = m_router_ip;
+  from.sin_family = IPPROTO_UDP;
+  from.sin_port = htons(67);
+  to.sin_addr.s_addr = m_current_ip;
+  to.sin_family = IPPROTO_UDP;
+  to.sin_port = udp_header.source_port;
+
+  const u8* router_ip_ptr = reinterpret_cast<const u8*>(&m_router_ip);
+  const std::vector<u8> ip_part(router_ip_ptr, router_ip_ptr + sizeof(m_router_ip));
+
+  const std::vector<u8> timeout_24h = {0, 1, 0x51, 0x80};
+
+  const Common::MACAddress bba_mac =
+      Common::BitCastPtr<Common::MACAddress>(&m_eth_ref->mBbaMem[BBA_NAFR_PAR0]);
+  Common::DHCPPacket reply;
+  reply.body = Common::DHCPBody(request.transaction_id, bba_mac, m_current_ip, m_router_ip);
+
+  // options
+  // send our emulated lan settings
+
+  (dhcp.options.size() == 0 || dhcp.options[0].size() < 2 || dhcp.options[0].at(2) == 1) ?
+      reply.AddOption(53, {2}) :  // default, send a suggestion
+      reply.AddOption(53, {5});
+  reply.AddOption(54, ip_part);                                    // dhcp server ip
+  reply.AddOption(51, timeout_24h);                                // lease time 24h
+  reply.AddOption(58, timeout_24h);                                // renewal time
+  reply.AddOption(59, timeout_24h);                                // rebind time
+  reply.AddOption(1, {255, 255, 255, 0});                          // submask
+  reply.AddOption(28, {ip_part[0], ip_part[1], ip_part[2], 255});  // broadcast ip
+  reply.AddOption(6, ip_part);                                     // dns server
+  reply.AddOption(15, {0x6c, 0x61, 0x6e});                         // domain name "lan"
+  reply.AddOption(3, ip_part);                                     // router ip
+  reply.AddOption(255, {});                                        // end
+
+  Common::UDPPacket response(bba_mac, m_fake_mac, from, to, reply.Build());
+
+  WriteToQueue(response.Build());
+}
+
+StackRef* CEXIETHERNET::BuiltInBBAInterface::GetAvailableSlot(u16 port)
+{
+  if (port > 0)  // existing connection?
+  {
+    for (auto& ref : network_ref)
+    {
+      if (ref.ip != 0 && ref.local == port)
+        return &ref;
+    }
+  }
+  for (auto& ref : network_ref)
+  {
+    if (ref.ip == 0)
+      return &ref;
+  }
+  return nullptr;
+}
+
+StackRef* CEXIETHERNET::BuiltInBBAInterface::GetTCPSlot(u16 src_port, u16 dst_port, u32 ip)
+{
+  for (auto& ref : network_ref)
+  {
+    if (ref.ip == ip && ref.remote == dst_port && ref.local == src_port)
+    {
+      return &ref;
+    }
+  }
+  return nullptr;
+}
+
+std::vector<u8> BuildFINFrame(StackRef* ref)
+{
+  Common::TCPPacket result(ref->bba_mac, ref->my_mac, ref->from, ref->to, ref->seq_num,
+                           ref->ack_num, TCP_FLAG_FIN | TCP_FLAG_ACK | TCP_FLAG_RST);
+
+  for (auto& tcp_buf : ref->tcp_buffers)
+    tcp_buf.used = false;
+  return result.Build();
+}
+
+std::vector<u8> BuildAckFrame(StackRef* ref)
+{
+  Common::TCPPacket result(ref->bba_mac, ref->my_mac, ref->from, ref->to, ref->seq_num,
+                           ref->ack_num, TCP_FLAG_ACK);
+  return result.Build();
+}
+
+void CEXIETHERNET::BuiltInBBAInterface::HandleTCPFrame(const Common::TCPPacket& packet)
+{
+  const auto& [hwdata, ip_header, tcp_header, ip_options, tcp_options, data] = packet;
+  sf::IpAddress target;
+  StackRef* ref = GetTCPSlot(tcp_header.source_port, tcp_header.destination_port,
+                             Common::BitCast<u32>(ip_header.destination_addr));
+  const u16 properties = ntohs(tcp_header.properties);
+  if (properties & (TCP_FLAG_FIN | TCP_FLAG_RST))
+  {
+    if (ref == nullptr)
+      return;  // not found
+
+    ref->ack_num++;
+    WriteToQueue(BuildFINFrame(ref));
+    ref->ip = 0;
+    ref->tcp_socket.disconnect();
+  }
+  else if (properties & TCP_FLAG_SIN)
+  {
+    // new connection
+    if (ref != nullptr)
+      return;
+    ref = GetAvailableSlot(0);
+
+    ref->delay = GetTickCountStd();
+    ref->local = tcp_header.source_port;
+    ref->remote = tcp_header.destination_port;
+    ref->ack_num = ntohl(tcp_header.sequence_number) + 1;
+    ref->ack_base = ref->ack_num;
+    ref->seq_num = 0x1000000;
+    ref->window_size = ntohl(tcp_header.window_size);
+    ref->type = IPPROTO_TCP;
+    for (auto& tcp_buf : ref->tcp_buffers)
+      tcp_buf.used = false;
+    ref->from.sin_addr.s_addr = Common::BitCast<u32>(ip_header.destination_addr);
+    ref->from.sin_port = tcp_header.destination_port;
+    ref->to.sin_addr.s_addr = Common::BitCast<u32>(ip_header.source_addr);
+    ref->to.sin_port = tcp_header.source_port;
+    ref->bba_mac = Common::BitCastPtr<Common::MACAddress>(&m_eth_ref->mBbaMem[BBA_NAFR_PAR0]);
+    ref->my_mac = m_fake_mac;
+    ref->tcp_socket.setBlocking(false);
+
+    // reply with a sin_ack
+    Common::TCPPacket result(ref->bba_mac, ref->my_mac, ref->from, ref->to, ref->seq_num,
+                             ref->ack_num, TCP_FLAG_SIN | TCP_FLAG_ACK);
+
+    result.tcp_options = {0x02, 0x04, 0x05, 0xb4, 0x01, 0x01, 0x01, 0x01};
+
+    ref->seq_num++;
+    target = sf::IpAddress(ntohl(Common::BitCast<u32>(ip_header.destination_addr)));
+    ref->tcp_socket.connect(target, ntohs(tcp_header.destination_port));
+    ref->ready = false;
+    ref->ip = Common::BitCast<u32>(ip_header.destination_addr);
+
+    ref->tcp_buffers[0].data = result.Build();
+    ref->tcp_buffers[0].seq_id = ref->seq_num - 1;
+    ref->tcp_buffers[0].tick = GetTickCountStd() - 900;  // delay
+    ref->tcp_buffers[0].used = true;
+  }
+  else
+  {
+    // data packet
+    if (ref == nullptr)
+      return;  // not found
+
+    const int size =
+        ntohs(ip_header.total_len) - ip_header.DefinedSize() - tcp_header.GetHeaderSize();
+    const u32 this_seq = ntohl(tcp_header.sequence_number);
+
+    if (size > 0)
+    {
+      // only if contain data
+      if (static_cast<int>(this_seq - ref->ack_num) >= 0 && data.size() >= size)
+      {
+        ref->tcp_socket.send(data.data(), size);
+        ref->ack_num += size;
+      }
+
+      // send ack
+      WriteToQueue(BuildAckFrame(ref));
+    }
+    // update windows size
+    ref->window_size = ntohs(tcp_header.window_size);
+
+    // clear any ack data
+    if (ntohs(tcp_header.properties) & TCP_FLAG_ACK)
+    {
+      const u32 ack_num = ntohl(tcp_header.acknowledgement_number);
+      for (auto& tcp_buf : ref->tcp_buffers)
+      {
+        if (!tcp_buf.used || tcp_buf.seq_id >= ack_num)
+          continue;
+
+        Common::PacketView view(tcp_buf.data.data(), tcp_buf.data.size());
+        auto tcp_packet = view.GetTCPPacket();  // This is always a tcp packet
+        if (!tcp_packet.has_value())            // should never happen but just in case
+          continue;
+
+        const u32 seq_end = static_cast<u32>(tcp_buf.seq_id + tcp_packet->data.size());
+        if (seq_end <= ack_num)
+        {
+          tcp_buf.used = false;  // confirmed data received
+          if (!ref->ready && !ref->tcp_buffers[0].used)
+            ref->ready = true;
+          continue;
+        }
+        // partial data, adjust the packet for next ack
+        const u16 ack_size = ack_num - tcp_buf.seq_id;
+        tcp_packet->data.erase(tcp_packet->data.begin(), tcp_packet->data.begin() + ack_size);
+
+        tcp_buf.seq_id += ack_size;
+        tcp_packet->tcp_header.sequence_number = htonl(tcp_buf.seq_id);
+        tcp_buf.data = tcp_packet->Build();
+      }
+    }
+  }
+}
+
+// This is a little hack, some games open a UDP port
+// and listen to it. We open it on our side manually.
+void CEXIETHERNET::BuiltInBBAInterface::InitUDPPort(u16 port)
+{
+  StackRef* ref = GetAvailableSlot(htons(port));
+  if (ref == nullptr || ref->ip != 0)
+    return;
+  ref->ip = m_router_ip;  // change for ip
+  ref->local = htons(port);
+  ref->remote = htons(port);
+  ref->type = IPPROTO_UDP;
+  ref->bba_mac = Common::BitCastPtr<Common::MACAddress>(&m_eth_ref->mBbaMem[BBA_NAFR_PAR0]);
+  ref->my_mac = m_fake_mac;
+  ref->from.sin_addr.s_addr = 0;
+  ref->from.sin_port = htons(port);
+  ref->to.sin_addr.s_addr = m_current_ip;
+  ref->to.sin_port = htons(port);
+  ref->udp_socket.setBlocking(false);
+  if (ref->udp_socket.bind(port) != sf::Socket::Done)
+  {
+    ERROR_LOG_FMT(SP1, "Couldn't open UDP socket");
+    PanicAlertFmt("Could't open port {:x}, this game might not work proprely in LAN mode.", port);
+    return;
+  }
+}
+
+void CEXIETHERNET::BuiltInBBAInterface::HandleUDPFrame(const Common::UDPPacket& packet)
+{
+  const auto& [hwdata, ip_header, udp_header, ip_options, data] = packet;
+  sf::IpAddress target;
+  const u32 destination_addr = ip_header.destination_addr == Common::IP_ADDR_ANY ?
+                                   m_router_ip :  // dns request
+                                   Common::BitCast<u32>(ip_header.destination_addr);
+
+  StackRef* ref = GetAvailableSlot(udp_header.source_port);
+  if (ref->ip == 0)
+  {
+    ref->ip = destination_addr;  // change for ip
+    ref->local = udp_header.source_port;
+    ref->remote = udp_header.destination_port;
+    ref->type = IPPROTO_UDP;
+    ref->bba_mac = Common::BitCastPtr<Common::MACAddress>(&m_eth_ref->mBbaMem[BBA_NAFR_PAR0]);
+    ref->my_mac = m_fake_mac;
+    ref->from.sin_addr.s_addr = destination_addr;
+    ref->from.sin_port = udp_header.destination_port;
+    ref->to.sin_addr.s_addr = Common::BitCast<u32>(ip_header.source_addr);
+    ref->to.sin_port = udp_header.source_port;
+    ref->udp_socket.setBlocking(false);
+    if (ref->udp_socket.bind(htons(udp_header.source_port)) != sf::Socket::Done)
+    {
+      PanicAlertFmt(
+          "Port {:x} is already in use, this game might not work as intented in LAN Mode.",
+          htons(udp_header.source_port));
+      if (ref->udp_socket.bind(sf::Socket::AnyPort) != sf::Socket::Done)
+      {
+        ERROR_LOG_FMT(SP1, "Couldn't open UDP socket");
+        return;
+      }
+      if (ntohs(udp_header.destination_port) == 1900)
+      {
+        InitUDPPort(26512);  // MK DD and 1080
+        InitUDPPort(26502);  // Air Ride
+        if (udp_header.length > 150)
+        {
+          // Quick hack to unlock the connection, throw it back at him
+          Common::UDPPacket reply = packet;
+          reply.eth_header.destination = hwdata.source;
+          reply.eth_header.source = hwdata.destination;
+          reply.ip_header.destination_addr = ip_header.source_addr;
+          if (ip_header.destination_addr == Common::IP_ADDR_SSDP)
+            reply.ip_header.source_addr = Common::IP_ADDR_BROADCAST;
+          else
+            reply.ip_header.source_addr = Common::BitCast<Common::IPAddress>(destination_addr);
+          WriteToQueue(reply.Build());
+        }
+      }
+    }
+  }
+  if (ntohs(udp_header.destination_port) == 53)
+    target = sf::IpAddress(m_dns_ip.c_str());  // dns server ip
+  else if (ip_header.destination_addr == Common::IP_ADDR_SSDP)
+    target = sf::IpAddress(0xFFFFFFFF);  // force real broadcast
+  else
+    target = sf::IpAddress(ntohl(Common::BitCast<u32>(ip_header.destination_addr)));
+  ref->udp_socket.send(data.data(), data.size(), target, ntohs(udp_header.destination_port));
+}
+
+bool CEXIETHERNET::BuiltInBBAInterface::SendFrame(const u8* frame, u32 size)
+{
+  std::lock_guard<std::mutex> lock(m_mtx);
+  const Common::PacketView view(frame, size);
+
+  const std::optional<u16> ethertype = view.GetEtherType();
+  if (!ethertype.has_value())
+  {
+    ERROR_LOG_FMT(SP1, "Unable to send frame with invalid ethernet header");
+    return false;
+  }
+
+  switch (*ethertype)
+  {
+  case Common::IPV4_ETHERTYPE:
+  {
+    const std::optional<u8> ip_proto = view.GetIPProto();
+    if (!ip_proto.has_value())
+    {
+      ERROR_LOG_FMT(SP1, "Unable to send frame with invalid IP header");
+      return false;
+    }
+
+    switch (*ip_proto)
+    {
+    case IPPROTO_UDP:
+    {
+      const auto udp_packet = view.GetUDPPacket();
+      if (!udp_packet.has_value())
+      {
+        ERROR_LOG_FMT(SP1, "Unable to send frame with invalid UDP header");
+        return false;
+      }
+
+      if (ntohs(udp_packet->udp_header.destination_port) == 67)
+      {
+        HandleDHCP(*udp_packet);
+      }
+      else
+      {
+        HandleUDPFrame(*udp_packet);
+      }
+      break;
+    }
+
+    case IPPROTO_TCP:
+    {
+      const auto tcp_packet = view.GetTCPPacket();
+      if (!tcp_packet.has_value())
+      {
+        ERROR_LOG_FMT(SP1, "Unable to send frame with invalid TCP header");
+        return false;
+      }
+
+      HandleTCPFrame(*tcp_packet);
+      break;
+    }
+    }
+    break;
+  }
+
+  case Common::ARP_ETHERTYPE:
+  {
+    const auto arp_packet = view.GetARPPacket();
+    if (!arp_packet.has_value())
+    {
+      ERROR_LOG_FMT(SP1, "Unable to send frame with invalid ARP header");
+      return false;
+    }
+
+    HandleARP(*arp_packet);
+    break;
+  }
+
+  default:
+    ERROR_LOG_FMT(SP1, "Unsupported EtherType {#06x}", *ethertype);
+    return false;
+  }
+
+  m_eth_ref->SendComplete();
+  return true;
+}
+
+std::optional<std::vector<u8>> TryGetDataFromSocket(StackRef* ref)
+{
+  size_t datasize = 0;  // Set by socket.receive using a non-const reference
+  unsigned short remote_port;
+
+  switch (ref->type)
+  {
+  case IPPROTO_UDP:
+  {
+    std::array<u8, MAX_UDP_LENGTH> buffer;
+    ref->udp_socket.receive(buffer.data(), MAX_UDP_LENGTH, datasize, ref->target, remote_port);
+    if (datasize > 0)
+    {
+      ref->from.sin_port = htons(remote_port);
+      ref->from.sin_addr.s_addr = htonl(ref->target.toInteger());
+      const std::vector<u8> udp_data(buffer.begin(), buffer.begin() + datasize);
+      Common::UDPPacket packet(ref->bba_mac, ref->my_mac, ref->from, ref->to, udp_data);
+      return packet.Build();
+    }
+    break;
+  }
+
+  case IPPROTO_TCP:
+    sf::Socket::Status st = sf::Socket::Status::Done;
+    TcpBuffer* tcp_buffer = nullptr;
+    for (auto& tcp_buf : ref->tcp_buffers)
+    {
+      if (tcp_buf.used)
+        continue;
+      tcp_buffer = &tcp_buf;
+      break;
+    }
+
+    // set default size to 0 to avoid issue
+    datasize = 0;
+    const bool can_go = (GetTickCountStd() - ref->poke_time > 100 || ref->window_size > 2000);
+    std::array<u8, MAX_TCP_LENGTH> buffer;
+    if (tcp_buffer != nullptr && ref->ready && can_go)
+      st = ref->tcp_socket.receive(buffer.data(), MAX_TCP_LENGTH, datasize);
+
+    if (datasize > 0)
+    {
+      Common::TCPPacket packet(ref->bba_mac, ref->my_mac, ref->from, ref->to, ref->seq_num,
+                               ref->ack_num, TCP_FLAG_ACK);
+      packet.data = std::vector<u8>(buffer.begin(), buffer.begin() + datasize);
+
+      // build buffer
+      tcp_buffer->seq_id = ref->seq_num;
+      tcp_buffer->tick = GetTickCountStd();
+      tcp_buffer->data = packet.Build();
+      tcp_buffer->seq_id = ref->seq_num;
+      tcp_buffer->used = true;
+      ref->seq_num += static_cast<u32>(datasize);
+      ref->poke_time = GetTickCountStd();
+      return tcp_buffer->data;
+    }
+    if (GetTickCountStd() - ref->delay > 3000)
+    {
+      if (st == sf::Socket::Disconnected || st == sf::Socket::Error)
+      {
+        ref->ip = 0;
+        ref->tcp_socket.disconnect();
+        return BuildFINFrame(ref);
+      }
+    }
+    break;
+  }
+
+  return std::nullopt;
+}
+
+// Change the IP identification and recompute the checksum
+static void SetIPIdentification(u8* ptr, std::size_t size, u16 value)
+{
+  if (size < Common::EthernetHeader::SIZE + Common::IPv4Header::SIZE)
+    return;
+
+  u8* const ip_ptr = ptr + Common::EthernetHeader::SIZE;
+  const u8 ip_header_size = (*ip_ptr & 0xf) * 4;
+  if (size < Common::EthernetHeader::SIZE + ip_header_size)
+    return;
+
+  u8* const ip_id_ptr = ip_ptr + offsetof(Common::IPv4Header, identification);
+  Common::BitCastPtr<u16>(ip_id_ptr) = htons(value);
+
+  u8* const ip_checksum_ptr = ip_ptr + offsetof(Common::IPv4Header, header_checksum);
+  auto checksum_bitcast_ptr = Common::BitCastPtr<u16>(ip_checksum_ptr);
+  checksum_bitcast_ptr = u16(0);
+  checksum_bitcast_ptr = htons(Common::ComputeNetworkChecksum(ip_ptr, ip_header_size));
+}
+
+void CEXIETHERNET::BuiltInBBAInterface::ReadThreadHandler(CEXIETHERNET::BuiltInBBAInterface* self)
+{
+  while (!self->m_read_thread_shutdown.IsSet())
+  {
+    // make thread less cpu hungry
+    std::this_thread::sleep_for(std::chrono::milliseconds(1));
+
+    if (!self->m_read_enabled.IsSet())
+      continue;
+    size_t datasize = 0;
+
+    u8 wp = self->m_eth_ref->page_ptr(BBA_RWP);
+    const u8 rp = self->m_eth_ref->page_ptr(BBA_RRP);
+    if (rp > wp)
+      wp += 16;
+
+    if ((wp - rp) >= 8)
+      continue;
+
+    std::lock_guard<std::mutex> lock(self->m_mtx);
+    // process queue file first
+    if (self->m_queue_read != self->m_queue_write)
+    {
+      datasize = self->m_queue_data[self->m_queue_read].size();
+      if (datasize > BBA_RECV_SIZE)
+      {
+        ERROR_LOG_FMT(SP1, "Frame size is exceiding BBA capacity, frame stack might be corrupted"
+                           "Killing Dolphin...");
+        std::exit(0);
+      }
+      std::memcpy(self->m_eth_ref->mRecvBuffer.get(), self->m_queue_data[self->m_queue_read].data(),
+                  datasize);
+      self->m_queue_read++;
+      self->m_queue_read &= 15;
+    }
+    else
+    {
+      // test connections data
+      for (auto& net_ref : self->network_ref)
+      {
+        if (net_ref.ip == 0)
+          continue;
+        const auto socket_data = TryGetDataFromSocket(&net_ref);
+        if (socket_data.has_value())
+        {
+          datasize = socket_data->size();
+          std::memcpy(self->m_eth_ref->mRecvBuffer.get(), socket_data->data(), datasize);
+          break;
+        }
+      }
+    }
+
+    // test and add any sleeping tcp data
+    for (auto& net_ref : self->network_ref)
+    {
+      if (net_ref.ip == 0 || net_ref.type != IPPROTO_TCP)
+        continue;
+      for (auto& tcp_buf : net_ref.tcp_buffers)
+      {
+        if (!tcp_buf.used || (GetTickCountStd() - tcp_buf.tick) <= 1000)
+          continue;
+
+        tcp_buf.tick = GetTickCountStd();
+        // timmed out packet, resend
+        if (((self->m_queue_write + 1) & 15) != self->m_queue_read)
+        {
+          self->WriteToQueue(tcp_buf.data);
+        }
+      }
+    }
+
+    if (datasize > 0)
+    {
+      u8* buffer = reinterpret_cast<u8*>(self->m_eth_ref->mRecvBuffer.get());
+      Common::PacketView packet(buffer, datasize);
+      const auto packet_type = packet.GetEtherType();
+      if (packet_type.has_value() && packet_type == IP_PROTOCOL)
+      {
+        SetIPIdentification(buffer, datasize, ++self->m_ip_frame_id);
+      }
+      self->m_eth_ref->mRecvBufferLength = datasize > 64 ? static_cast<u32>(datasize) : 64;
+      self->m_eth_ref->RecvHandlePacket();
+    }
+  }
+}
+
+bool CEXIETHERNET::BuiltInBBAInterface::RecvInit()
+{
+  m_read_thread = std::thread(ReadThreadHandler, this);
+  return true;
+}
+
+void CEXIETHERNET::BuiltInBBAInterface::RecvStart()
+{
+  m_read_enabled.Set();
+}
+
+void CEXIETHERNET::BuiltInBBAInterface::RecvStop()
+{
+  m_read_enabled.Clear();
+  for (auto& net_ref : network_ref)
+  {
+    if (net_ref.ip != 0)
+    {
+      net_ref.type == IPPROTO_TCP ? net_ref.tcp_socket.disconnect() : net_ref.udp_socket.unbind();
+    }
+    net_ref.ip = 0;
+  }
+  m_queue_read = 0;
+  m_queue_write = 0;
+}
+}  // namespace ExpansionInterface

Source/Core/Core/HW/EXI/BBA/BuiltIn.h

@@ -0,0 +1,58 @@
+// Copyright 2022 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#ifdef _WIN32
+#include <WinSock2.h>
+#else
+#include <netinet/in.h>
+#endif
+
+#include <SFML/Network.hpp>
+#include "Common/CommonTypes.h"
+#include "Common/Network.h"
+
+constexpr u16 TCP_FLAG_SIN = 0x2;
+constexpr u16 TCP_FLAG_ACK = 0x10;
+constexpr u16 TCP_FLAG_PSH = 0x8;
+constexpr u16 TCP_FLAG_FIN = 0x1;
+constexpr u16 TCP_FLAG_RST = 0x4;
+
+constexpr u16 IP_PROTOCOL = 0x800;
+constexpr u16 ARP_PROTOCOL = 0x806;
+
+constexpr u8 MAX_TCP_BUFFER = 4;
+constexpr u16 MAX_UDP_LENGTH = 1500;
+constexpr u16 MAX_TCP_LENGTH = 440;
+
+struct TcpBuffer
+{
+  bool used;
+  u64 tick;
+  u32 seq_id;
+  std::vector<u8> data;
+};
+
+struct StackRef
+{
+  u32 ip;
+  u16 local;
+  u16 remote;
+  u16 type;
+  sf::IpAddress target;
+  u32 seq_num;
+  u32 ack_num;
+  u32 ack_base;
+  u16 window_size;
+  u64 delay;
+  std::array<TcpBuffer, MAX_TCP_BUFFER> tcp_buffers;
+  bool ready;
+  sockaddr_in from;
+  sockaddr_in to;
+  Common::MACAddress bba_mac{};
+  Common::MACAddress my_mac{};
+  sf::UdpSocket udp_socket;
+  sf::TcpSocket tcp_socket;
+  u64 poke_time;
+};

Source/Core/Core/HW/EXI/EXI_Device.cpp

@@ -143,6 +143,10 @@ std::unique_ptr<IEXIDevice> EXIDevice_Create(const EXIDeviceType device_type, co
     result = std::make_unique<CEXIETHERNET>(BBADeviceType::XLINK);
     break;
 
+  case EXIDeviceType::EthernetBuiltIn:
+    result = std::make_unique<CEXIETHERNET>(BBADeviceType::BuiltIn);
+    break;
+
   case EXIDeviceType::Gecko:
     result = std::make_unique<CEXIGecko>();
     break;

Source/Core/Core/HW/EXI/EXI_Device.h

@@ -37,6 +37,7 @@ enum class EXIDeviceType : int
   EthernetXLink,
   // Only used on Apple devices.
   EthernetTapServer,
+  EthernetBuiltIn,
   None = 0xFF
 };
 
@@ -79,7 +80,7 @@ std::unique_ptr<IEXIDevice> EXIDevice_Create(EXIDeviceType device_type, int chan
 
 template <>
 struct fmt::formatter<ExpansionInterface::EXIDeviceType>
-    : EnumFormatter<ExpansionInterface::EXIDeviceType::EthernetTapServer>
+    : EnumFormatter<ExpansionInterface::EXIDeviceType::EthernetBuiltIn>
 {
   static constexpr array_type names = {
       _trans("Dummy"),
@@ -95,6 +96,7 @@ struct fmt::formatter<ExpansionInterface::EXIDeviceType>
       _trans("Advance Game Port"),
       _trans("Broadband Adapter (XLink Kai)"),
       _trans("Broadband Adapter (tapserver)"),
+      _trans("Broadband Adapter (Built In)"),
   };
 
   constexpr formatter() : EnumFormatter(names) {}

Source/Core/Core/HW/EXI/EXI_DeviceEthernet.cpp

@@ -53,6 +53,11 @@ CEXIETHERNET::CEXIETHERNET(BBADeviceType type)
     INFO_LOG_FMT(SP1, "Created tapserver physical network interface.");
     break;
 #endif
+  case BBADeviceType::BuiltIn:
+    m_network_interface = std::make_unique<BuiltInBBAInterface>(
+        this, Config::Get(Config::MAIN_BBA_BUILTIN_DNS), Config::Get(Config::MAIN_BBA_BUILTIN_IP));
+    INFO_LOG_FMT(SP1, "Created Built in network interface.");
+    break;
   case BBADeviceType::XLINK:
     // TODO start BBA with network link down, bring it up after "connected" response from XLink
 
@@ -155,6 +160,17 @@ void CEXIETHERNET::ImmWrite(u32 data, u32 size)
     {
     case INTERRUPT:
       exi_status.interrupt &= data ^ 0xff;
+      // raise back if there is still data
+      if (page_ptr(BBA_RRP) != page_ptr(BBA_RWP))
+      {
+        if (mBbaMem[BBA_IMR] & INT_R)
+        {
+          mBbaMem[BBA_IR] |= INT_R;
+
+          exi_status.interrupt |= exi_status.TRANSFER;
+        }
+      }
+
       break;
     case INTERRUPT_MASK:
       exi_status.interrupt_mask = data;
@@ -228,9 +244,7 @@ void CEXIETHERNET::DMAWrite(u32 addr, u32 size)
 void CEXIETHERNET::DMARead(u32 addr, u32 size)
 {
   DEBUG_LOG_FMT(SP1, "DMA read: {:08x} {:x}", addr, size);
-
   Memory::CopyToEmu(addr, &mBbaMem[transfer.address], size);
-
   transfer.address += size;
 }
 
@@ -348,7 +362,6 @@ void CEXIETHERNET::MXCommandHandler(u32 data, u32 size)
       // MXSoftReset();
       m_network_interface->Activate();
     }
-
     if (((mBbaMem[BBA_NCRA] & NCRA_SR) ^ (data & NCRA_SR)) != 0)
     {
       DEBUG_LOG_FMT(SP1, "{} rx", (data & NCRA_SR) ? "start" : "stop");
@@ -415,7 +428,6 @@ void CEXIETHERNET::DirectFIFOWrite(const u8* data, u32 size)
 {
   // In direct mode, the hardware handles creating the state required by the
   // GMAC instead of finagling with packet descriptors and such
-
   u16* tx_fifo_count = (u16*)&mBbaMem[BBA_TXFIFOCNT];
 
   memcpy(tx_fifo.get() + *tx_fifo_count, data, size);
@@ -510,76 +522,80 @@ inline void CEXIETHERNET::inc_rwp()
 {
   u16* rwp = (u16*)&mBbaMem[BBA_RWP];
 
-  if (*rwp + 1 == page_ptr(BBA_RHBP))
+  if (*rwp == page_ptr(BBA_RHBP))
     *rwp = page_ptr(BBA_BP);
   else
     (*rwp)++;
 }
 
+inline void CEXIETHERNET::set_rwp(u16 value)
+{
+  u16* rwp = (u16*)&mBbaMem[BBA_RWP];
+  *rwp = value;
+}
+
 // This function is on the critical path for receiving data.
 // Be very careful about calling into the logger and other slow things
 bool CEXIETHERNET::RecvHandlePacket()
 {
   u8* write_ptr;
-  u8* end_ptr;
-  u8* read_ptr;
   Descriptor* descriptor;
   u32 status = 0;
   u16 rwp_initial = page_ptr(BBA_RWP);
-
+  u16 current_rwp = 0;
+  u32 off = 4;
   if (!RecvMACFilter())
     goto wait_for_next;
 
 #ifdef BBA_TRACK_PAGE_PTRS
   INFO_LOG_FMT(SP1, "RecvHandlePacket {:x}\n{}", mRecvBufferLength,
-               ArrayToString(mRecvBuffer, mRecvBufferLength, 0x100));
+               ArrayToString(mRecvBuffer.get(), mRecvBufferLength, 16));
 
   INFO_LOG_FMT(SP1, "{:x} {:x} {:x} {:x}", page_ptr(BBA_BP), page_ptr(BBA_RRP), page_ptr(BBA_RWP),
                page_ptr(BBA_RHBP));
 #endif
 
-  write_ptr = ptr_from_page_ptr(BBA_RWP);
+  write_ptr = &mBbaMem[page_ptr(BBA_RWP) << 8];
-  end_ptr = ptr_from_page_ptr(BBA_RHBP);
-  read_ptr = ptr_from_page_ptr(BBA_RRP);
 
   descriptor = (Descriptor*)write_ptr;
-  write_ptr += 4;
+  current_rwp = page_ptr(BBA_RWP);
-
+  DEBUG_LOG_FMT(SP1, "Frame recv: {:x}", mRecvBufferLength);
-  for (u32 i = 0, off = 4; i < mRecvBufferLength; ++i, ++off)
+  for (u32 i = 0; i < mRecvBufferLength; i++)
   {
-    *write_ptr++ = mRecvBuffer[i];
+    write_ptr[off] = mRecvBuffer[i];
-
+    off++;
-    if (off == 0xff)
+    if (off == 0x100)
     {
       off = 0;
-      inc_rwp();
+      // avoid increasing the BBA register while copying
-    }
+      // sometime the OS can try to process when it's not completed
+      current_rwp = current_rwp == page_ptr(BBA_RHBP) ? page_ptr(BBA_BP) : ++current_rwp;
 
-    if (write_ptr == end_ptr)
+      write_ptr = &mBbaMem[current_rwp << 8];
-      write_ptr = ptr_from_page_ptr(BBA_BP);
 
-    if (write_ptr == read_ptr)
+      if (page_ptr(BBA_RRP) == current_rwp)
-    {
+      {
-      /*
+        /*
-      halt copy
+        halt copy
-      if (cur_packet_size >= PAGE_SIZE)
+        if (cur_packet_size >= PAGE_SIZE)
-        desc.status |= FO | BF
+          desc.status |= FO | BF
-      if (RBFIM)
+        if (RBFIM)
-        raise RBFI
+          raise RBFI
-      if (AUTORCVR)
+        if (AUTORCVR)
-        discard bad packet
+          discard bad packet
-      else
+        else
-        inc MPC instead of receiving packets
+          inc MPC instead of receiving packets
-      */
+        */
-      status |= DESC_FO | DESC_BF;
+        status |= DESC_FO | DESC_BF;
-      mBbaMem[BBA_IR] |= mBbaMem[BBA_IMR] & INT_RBF;
+        mBbaMem[BBA_IR] |= mBbaMem[BBA_IMR] & INT_RBF;
-      break;
+        break;
+      }
     }
   }
 
   // Align up to next page
   if ((mRecvBufferLength + 4) % 256)
-    inc_rwp();
+    current_rwp = current_rwp == page_ptr(BBA_RHBP) ? page_ptr(BBA_BP) : ++current_rwp;
 
 #ifdef BBA_TRACK_PAGE_PTRS
   INFO_LOG_FMT(SP1, "{:x} {:x} {:x} {:x}", page_ptr(BBA_BP), page_ptr(BBA_RRP), page_ptr(BBA_RWP),
@@ -602,7 +618,9 @@ bool CEXIETHERNET::RecvHandlePacket()
     }
   }
 
-  descriptor->set(*(u16*)&mBbaMem[BBA_RWP], 4 + mRecvBufferLength, status);
+  descriptor->set(current_rwp, 4 + mRecvBufferLength, status);
+
+  set_rwp(current_rwp);
 
   mBbaMem[BBA_LRPS] = status;
 

Source/Core/Core/HW/EXI/EXI_DeviceEthernet.h

@@ -13,7 +13,10 @@
 
 #include <SFML/Network.hpp>
 
+#include <mutex>
 #include "Common/Flag.h"
+#include "Common/Network.h"
+#include "Core/HW/EXI/BBA/BuiltIn.h"
 #include "Core/HW/EXI/EXI_Device.h"
 
 class PointerWrap;
@@ -204,6 +207,7 @@ enum class BBADeviceType
 #if defined(__APPLE__)
   TAPSERVER,
 #endif
+  BuiltIn,
 };
 
 class CEXIETHERNET : public IEXIDevice
@@ -289,7 +293,6 @@ private:
     return ((u16)mBbaMem[index + 1] << 8) | mBbaMem[index];
   }
 
-  inline u8* ptr_from_page_ptr(int const index) const { return &mBbaMem[page_ptr(index) << 8]; }
   bool IsMXCommand(u32 const data);
   bool IsWriteCommand(u32 const data);
   const char* GetRegisterName() const;
@@ -299,9 +302,11 @@ private:
   void SendFromDirectFIFO();
   void SendFromPacketBuffer();
   void SendComplete();
+  void SendCompleteBack();
   u8 HashIndex(const u8* dest_eth_addr);
   bool RecvMACFilter();
   void inc_rwp();
+  void set_rwp(u16 value);
   bool RecvHandlePacket();
 
   std::unique_ptr<u8[]> mBbaMem;
@@ -413,6 +418,54 @@ private:
 #endif
   };
 
+  class BuiltInBBAInterface : public NetworkInterface
+  {
+  public:
+    BuiltInBBAInterface(CEXIETHERNET* eth_ref, std::string dns_ip, std::string local_ip)
+        : NetworkInterface(eth_ref), m_dns_ip(std::move(dns_ip)), m_local_ip(std::move(local_ip))
+    {
+    }
+    bool Activate() override;
+    void Deactivate() override;
+    bool IsActivated() override;
+    bool SendFrame(const u8* frame, u32 size) override;
+    bool RecvInit() override;
+    void RecvStart() override;
+    void RecvStop() override;
+
+  private:
+    std::string m_mac_id;
+    std::string m_dns_ip;
+    bool m_active = false;
+    u16 m_ip_frame_id = 0;
+    u8 m_queue_read = 0;
+    u8 m_queue_write = 0;
+    std::array<std::vector<u8>, 16> m_queue_data;
+    std::mutex m_mtx;
+    std::string m_local_ip;
+    u32 m_current_ip = 0;
+    u32 m_router_ip = 0;
+#if defined(WIN32) || defined(__linux__) || defined(__APPLE__) || defined(__FreeBSD__) ||          \
+    defined(__OpenBSD__) || defined(__NetBSD__) || defined(__HAIKU__)
+    std::array<StackRef, 10> network_ref{};  // max 10 at same time, i think most gc game had a
+                                             // limit of 8 in the gc framework
+    std::thread m_read_thread;
+    Common::Flag m_read_enabled;
+    Common::Flag m_read_thread_shutdown;
+    Common::MACAddress m_fake_mac{};
+    static void ReadThreadHandler(BuiltInBBAInterface* self);
+#endif
+    void WriteToQueue(const std::vector<u8>& data);
+    StackRef* GetAvailableSlot(u16 port);
+    StackRef* GetTCPSlot(u16 src_port, u16 dst_port, u32 ip);
+
+    void HandleARP(const Common::ARPPacket& packet);
+    void HandleDHCP(const Common::UDPPacket& packet);
+    void HandleTCPFrame(const Common::TCPPacket& packet);
+    void InitUDPPort(u16 port);
+    void HandleUDPFrame(const Common::UDPPacket& packet);
+  };
+
   std::unique_ptr<NetworkInterface> m_network_interface;
 
   std::unique_ptr<u8[]> mRecvBuffer;

Source/Core/DolphinLib.props

@@ -254,6 +254,7 @@
     <ClInclude Include="Core\HW\DVD\DVDMath.h" />
     <ClInclude Include="Core\HW\DVD\DVDThread.h" />
     <ClInclude Include="Core\HW\DVD\FileMonitor.h" />
+    <ClInclude Include="Core\HW\EXI\BBA\BuiltIn.h" />
     <ClInclude Include="Core\HW\EXI\BBA\TAP_Win32.h" />
     <ClInclude Include="Core\HW\EXI\EXI_Channel.h" />
     <ClInclude Include="Core\HW\EXI\EXI_Device.h" />
@@ -869,6 +870,7 @@
     <ClCompile Include="Core\HW\DVD\DVDMath.cpp" />
     <ClCompile Include="Core\HW\DVD\DVDThread.cpp" />
     <ClCompile Include="Core\HW\DVD\FileMonitor.cpp" />
+    <ClCompile Include="Core\HW\EXI\BBA\BuiltIn.cpp" />
     <ClCompile Include="Core\HW\EXI\BBA\TAP_Win32.cpp" />
     <ClCompile Include="Core\HW\EXI\BBA\XLINK_KAI_BBA.cpp" />
     <ClCompile Include="Core\HW\EXI\EXI_Channel.cpp" />

Source/Core/DolphinQt/Settings/BroadbandAdapterSettingsDialog.cpp

@@ -48,6 +48,15 @@ void BroadbandAdapterSettingsDialog::InitControls()
     window_title = tr("Broadband Adapter MAC Address");
     break;
 
+  case Type::BuiltIn:
+    address_label = new QLabel(tr("Enter the DNS server to use:"));
+    address_placeholder = QStringLiteral("8.8.8.8");
+    current_address = QString::fromStdString(Config::Get(Config::MAIN_BBA_BUILTIN_DNS));
+    description = new QLabel(tr("Use 8.8.8.8 for normal DNS, else enter your custom one"));
+
+    window_title = tr("Broadband Adapter DNS setting");
+    break;
+
   case Type::XLinkKai:
     address_label = new QLabel(tr("Enter IP address of device running the XLink Kai Client:"));
     address_placeholder = QString::fromStdString("127.0.0.1");
@@ -103,6 +112,9 @@ void BroadbandAdapterSettingsDialog::SaveAddress()
     Config::SetBaseOrCurrent(Config::MAIN_BBA_MAC, bba_new_address);
     break;
 
+  case Type::BuiltIn:
+    Config::SetBaseOrCurrent(Config::MAIN_BBA_BUILTIN_DNS, bba_new_address);
+    break;
   case Type::XLinkKai:
     Config::SetBaseOrCurrent(Config::MAIN_BBA_XLINK_IP, bba_new_address);
     break;

Source/Core/DolphinQt/Settings/BroadbandAdapterSettingsDialog.h

@@ -15,6 +15,7 @@ public:
   {
     Ethernet,
     XLinkKai,
+    BuiltIn
   };
 
   explicit BroadbandAdapterSettingsDialog(QWidget* target, Type bba_type);

Source/Core/DolphinQt/Settings/GameCubePane.cpp

@@ -120,6 +120,7 @@ void GameCubePane::CreateWidgets()
 #ifdef __APPLE__
            EXIDeviceType::EthernetTapServer,
 #endif
+           EXIDeviceType::EthernetBuiltIn,
        })
   {
     m_slot_combos[ExpansionInterface::Slot::SP1]->addItem(tr(fmt::format("{:n}", device).c_str()),
@@ -259,7 +260,8 @@ void GameCubePane::UpdateButton(ExpansionInterface::Slot slot)
     break;
   case ExpansionInterface::Slot::SP1:
     has_config = (device == ExpansionInterface::EXIDeviceType::Ethernet ||
-                  device == ExpansionInterface::EXIDeviceType::EthernetXLink);
+                  device == ExpansionInterface::EXIDeviceType::EthernetXLink ||
+                  device == ExpansionInterface::EXIDeviceType::EthernetBuiltIn);
     break;
   }
 
@@ -293,6 +295,11 @@ void GameCubePane::OnConfigPressed(ExpansionInterface::Slot slot)
     BroadbandAdapterSettingsDialog(this, BroadbandAdapterSettingsDialog::Type::XLinkKai).exec();
     return;
   }
+  case ExpansionInterface::EXIDeviceType::EthernetBuiltIn:
+  {
+    BroadbandAdapterSettingsDialog(this, BroadbandAdapterSettingsDialog::Type::BuiltIn).exec();
+    return;
+  }
   default:
     PanicAlertFmt("Unknown settings pressed for {}", device);
     return;