5 files changed, 1086 insertions, 0 deletions

diff --git a/src/core/internal_network/network.cpp b/src/core/internal_network/network.cpp
new file mode 100644
index 000000000..36c43cc8f
--- /dev/null
+++ b/src/core/internal_network/network.cpp
@@ -0,0 +1,637 @@
+// SPDX-FileCopyrightText: Copyright 2020 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <algorithm>
+#include <cstring>
+#include <limits>
+#include <utility>
+#include <vector>
+
+#include "common/error.h"
+
+#ifdef _WIN32
+#include <winsock2.h>
+#include <ws2tcpip.h>
+#elif YUZU_UNIX
+#include <arpa/inet.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <netdb.h>
+#include <netinet/in.h>
+#include <poll.h>
+#include <sys/socket.h>
+#include <unistd.h>
+#else
+#error "Unimplemented platform"
+#endif
+
+#include "common/assert.h"
+#include "common/common_types.h"
+#include "common/logging/log.h"
+#include "common/settings.h"
+#include "core/internal_network/network.h"
+#include "core/internal_network/network_interface.h"
+#include "core/internal_network/sockets.h"
+
+namespace Network {
+
+namespace {
+
+#ifdef _WIN32
+
+using socklen_t = int;
+
+void Initialize() {
+    WSADATA wsa_data;
+    (void)WSAStartup(MAKEWORD(2, 2), &wsa_data);
+}
+
+void Finalize() {
+    WSACleanup();
+}
+
+sockaddr TranslateFromSockAddrIn(SockAddrIn input) {
+    sockaddr_in result;
+
+#if YUZU_UNIX
+    result.sin_len = sizeof(result);
+#endif
+
+    switch (static_cast<Domain>(input.family)) {
+    case Domain::INET:
+        result.sin_family = AF_INET;
+        break;
+    default:
+        UNIMPLEMENTED_MSG("Unhandled sockaddr family={}", input.family);
+        result.sin_family = AF_INET;
+        break;
+    }
+
+    result.sin_port = htons(input.portno);
+
+    auto& ip = result.sin_addr.S_un.S_un_b;
+    ip.s_b1 = input.ip[0];
+    ip.s_b2 = input.ip[1];
+    ip.s_b3 = input.ip[2];
+    ip.s_b4 = input.ip[3];
+
+    sockaddr addr;
+    std::memcpy(&addr, &result, sizeof(addr));
+    return addr;
+}
+
+LINGER MakeLinger(bool enable, u32 linger_value) {
+    ASSERT(linger_value <= std::numeric_limits<u_short>::max());
+
+    LINGER value;
+    value.l_onoff = enable ? 1 : 0;
+    value.l_linger = static_cast<u_short>(linger_value);
+    return value;
+}
+
+bool EnableNonBlock(SOCKET fd, bool enable) {
+    u_long value = enable ? 1 : 0;
+    return ioctlsocket(fd, FIONBIO, &value) != SOCKET_ERROR;
+}
+
+Errno TranslateNativeError(int e) {
+    switch (e) {
+    case WSAEBADF:
+        return Errno::BADF;
+    case WSAEINVAL:
+        return Errno::INVAL;
+    case WSAEMFILE:
+        return Errno::MFILE;
+    case WSAENOTCONN:
+        return Errno::NOTCONN;
+    case WSAEWOULDBLOCK:
+        return Errno::AGAIN;
+    case WSAECONNREFUSED:
+        return Errno::CONNREFUSED;
+    case WSAEHOSTUNREACH:
+        return Errno::HOSTUNREACH;
+    case WSAENETDOWN:
+        return Errno::NETDOWN;
+    case WSAENETUNREACH:
+        return Errno::NETUNREACH;
+    default:
+        return Errno::OTHER;
+    }
+}
+
+#elif YUZU_UNIX // ^ _WIN32 v YUZU_UNIX
+
+using SOCKET = int;
+using WSAPOLLFD = pollfd;
+using ULONG = u64;
+
+constexpr SOCKET INVALID_SOCKET = -1;
+constexpr SOCKET SOCKET_ERROR = -1;
+
+constexpr int SD_RECEIVE = SHUT_RD;
+constexpr int SD_SEND = SHUT_WR;
+constexpr int SD_BOTH = SHUT_RDWR;
+
+void Initialize() {}
+
+void Finalize() {}
+
+sockaddr TranslateFromSockAddrIn(SockAddrIn input) {
+    sockaddr_in result;
+
+    switch (static_cast<Domain>(input.family)) {
+    case Domain::INET:
+        result.sin_family = AF_INET;
+        break;
+    default:
+        UNIMPLEMENTED_MSG("Unhandled sockaddr family={}", input.family);
+        result.sin_family = AF_INET;
+        break;
+    }
+
+    result.sin_port = htons(input.portno);
+
+    result.sin_addr.s_addr = input.ip[0] | input.ip[1] << 8 | input.ip[2] << 16 | input.ip[3] << 24;
+
+    sockaddr addr;
+    std::memcpy(&addr, &result, sizeof(addr));
+    return addr;
+}
+
+int WSAPoll(WSAPOLLFD* fds, ULONG nfds, int timeout) {
+    return poll(fds, static_cast<nfds_t>(nfds), timeout);
+}
+
+int closesocket(SOCKET fd) {
+    return close(fd);
+}
+
+linger MakeLinger(bool enable, u32 linger_value) {
+    linger value;
+    value.l_onoff = enable ? 1 : 0;
+    value.l_linger = linger_value;
+    return value;
+}
+
+bool EnableNonBlock(int fd, bool enable) {
+    int flags = fcntl(fd, F_GETFL);
+    if (flags == -1) {
+        return false;
+    }
+    if (enable) {
+        flags |= O_NONBLOCK;
+    } else {
+        flags &= ~O_NONBLOCK;
+    }
+    return fcntl(fd, F_SETFL, flags) == 0;
+}
+
+Errno TranslateNativeError(int e) {
+    switch (e) {
+    case EBADF:
+        return Errno::BADF;
+    case EINVAL:
+        return Errno::INVAL;
+    case EMFILE:
+        return Errno::MFILE;
+    case ENOTCONN:
+        return Errno::NOTCONN;
+    case EAGAIN:
+        return Errno::AGAIN;
+    case ECONNREFUSED:
+        return Errno::CONNREFUSED;
+    case EHOSTUNREACH:
+        return Errno::HOSTUNREACH;
+    case ENETDOWN:
+        return Errno::NETDOWN;
+    case ENETUNREACH:
+        return Errno::NETUNREACH;
+    default:
+        return Errno::OTHER;
+    }
+}
+
+#endif
+
+Errno GetAndLogLastError() {
+#ifdef _WIN32
+    int e = WSAGetLastError();
+#else
+    int e = errno;
+#endif
+    const Errno err = TranslateNativeError(e);
+    if (err == Errno::AGAIN) {
+        return err;
+    }
+    LOG_ERROR(Network, "Socket operation error: {}", Common::NativeErrorToString(e));
+    return err;
+}
+
+int TranslateDomain(Domain domain) {
+    switch (domain) {
+    case Domain::INET:
+        return AF_INET;
+    default:
+        UNIMPLEMENTED_MSG("Unimplemented domain={}", domain);
+        return 0;
+    }
+}
+
+int TranslateType(Type type) {
+    switch (type) {
+    case Type::STREAM:
+        return SOCK_STREAM;
+    case Type::DGRAM:
+        return SOCK_DGRAM;
+    default:
+        UNIMPLEMENTED_MSG("Unimplemented type={}", type);
+        return 0;
+    }
+}
+
+int TranslateProtocol(Protocol protocol) {
+    switch (protocol) {
+    case Protocol::TCP:
+        return IPPROTO_TCP;
+    case Protocol::UDP:
+        return IPPROTO_UDP;
+    default:
+        UNIMPLEMENTED_MSG("Unimplemented protocol={}", protocol);
+        return 0;
+    }
+}
+
+SockAddrIn TranslateToSockAddrIn(sockaddr input_) {
+    sockaddr_in input;
+    std::memcpy(&input, &input_, sizeof(input));
+
+    SockAddrIn result;
+
+    switch (input.sin_family) {
+    case AF_INET:
+        result.family = Domain::INET;
+        break;
+    default:
+        UNIMPLEMENTED_MSG("Unhandled sockaddr family={}", input.sin_family);
+        result.family = Domain::INET;
+        break;
+    }
+
+    result.portno = ntohs(input.sin_port);
+
+    result.ip = TranslateIPv4(input.sin_addr);
+
+    return result;
+}
+
+short TranslatePollEvents(PollEvents events) {
+    short result = 0;
+
+    if (True(events & PollEvents::In)) {
+        events &= ~PollEvents::In;
+        result |= POLLIN;
+    }
+    if (True(events & PollEvents::Pri)) {
+        events &= ~PollEvents::Pri;
+#ifdef _WIN32
+        LOG_WARNING(Service, "Winsock doesn't support POLLPRI");
+#else
+        result |= POLLPRI;
+#endif
+    }
+    if (True(events & PollEvents::Out)) {
+        events &= ~PollEvents::Out;
+        result |= POLLOUT;
+    }
+
+    UNIMPLEMENTED_IF_MSG((u16)events != 0, "Unhandled guest events=0x{:x}", (u16)events);
+
+    return result;
+}
+
+PollEvents TranslatePollRevents(short revents) {
+    PollEvents result{};
+    const auto translate = [&result, &revents](short host, PollEvents guest) {
+        if ((revents & host) != 0) {
+            revents &= static_cast<short>(~host);
+            result |= guest;
+        }
+    };
+
+    translate(POLLIN, PollEvents::In);
+    translate(POLLPRI, PollEvents::Pri);
+    translate(POLLOUT, PollEvents::Out);
+    translate(POLLERR, PollEvents::Err);
+    translate(POLLHUP, PollEvents::Hup);
+
+    UNIMPLEMENTED_IF_MSG(revents != 0, "Unhandled host revents=0x{:x}", revents);
+
+    return result;
+}
+
+template <typename T>
+Errno SetSockOpt(SOCKET fd, int option, T value) {
+    const int result =
+        setsockopt(fd, SOL_SOCKET, option, reinterpret_cast<const char*>(&value), sizeof(value));
+    if (result != SOCKET_ERROR) {
+        return Errno::SUCCESS;
+    }
+    return GetAndLogLastError();
+}
+
+} // Anonymous namespace
+
+NetworkInstance::NetworkInstance() {
+    Initialize();
+}
+
+NetworkInstance::~NetworkInstance() {
+    Finalize();
+}
+
+std::optional<IPv4Address> GetHostIPv4Address() {
+    const std::string& selected_network_interface = Settings::values.network_interface.GetValue();
+    const auto network_interfaces = Network::GetAvailableNetworkInterfaces();
+    if (network_interfaces.size() == 0) {
+        LOG_ERROR(Network, "GetAvailableNetworkInterfaces returned no interfaces");
+        return {};
+    }
+
+    const auto res =
+        std::ranges::find_if(network_interfaces, [&selected_network_interface](const auto& iface) {
+            return iface.name == selected_network_interface;
+        });
+
+    if (res != network_interfaces.end()) {
+        char ip_addr[16] = {};
+        ASSERT(inet_ntop(AF_INET, &res->ip_address, ip_addr, sizeof(ip_addr)) != nullptr);
+        return TranslateIPv4(res->ip_address);
+    } else {
+        LOG_ERROR(Network, "Couldn't find selected interface \"{}\"", selected_network_interface);
+        return {};
+    }
+}
+
+std::pair<s32, Errno> Poll(std::vector<PollFD>& pollfds, s32 timeout) {
+    const size_t num = pollfds.size();
+
+    std::vector<WSAPOLLFD> host_pollfds(pollfds.size());
+    std::transform(pollfds.begin(), pollfds.end(), host_pollfds.begin(), [](PollFD fd) {
+        WSAPOLLFD result;
+        result.fd = fd.socket->fd;
+        result.events = TranslatePollEvents(fd.events);
+        result.revents = 0;
+        return result;
+    });
+
+    const int result = WSAPoll(host_pollfds.data(), static_cast<ULONG>(num), timeout);
+    if (result == 0) {
+        ASSERT(std::all_of(host_pollfds.begin(), host_pollfds.end(),
+                           [](WSAPOLLFD fd) { return fd.revents == 0; }));
+        return {0, Errno::SUCCESS};
+    }
+
+    for (size_t i = 0; i < num; ++i) {
+        pollfds[i].revents = TranslatePollRevents(host_pollfds[i].revents);
+    }
+
+    if (result > 0) {
+        return {result, Errno::SUCCESS};
+    }
+
+    ASSERT(result == SOCKET_ERROR);
+
+    return {-1, GetAndLogLastError()};
+}
+
+Socket::~Socket() {
+    if (fd == INVALID_SOCKET) {
+        return;
+    }
+    (void)closesocket(fd);
+    fd = INVALID_SOCKET;
+}
+
+Socket::Socket(Socket&& rhs) noexcept : fd{std::exchange(rhs.fd, INVALID_SOCKET)} {}
+
+Errno Socket::Initialize(Domain domain, Type type, Protocol protocol) {
+    fd = socket(TranslateDomain(domain), TranslateType(type), TranslateProtocol(protocol));
+    if (fd != INVALID_SOCKET) {
+        return Errno::SUCCESS;
+    }
+
+    return GetAndLogLastError();
+}
+
+std::pair<Socket::AcceptResult, Errno> Socket::Accept() {
+    sockaddr addr;
+    socklen_t addrlen = sizeof(addr);
+    const SOCKET new_socket = accept(fd, &addr, &addrlen);
+
+    if (new_socket == INVALID_SOCKET) {
+        return {AcceptResult{}, GetAndLogLastError()};
+    }
+
+    AcceptResult result;
+    result.socket = std::make_unique<Socket>();
+    result.socket->fd = new_socket;
+
+    ASSERT(addrlen == sizeof(sockaddr_in));
+    result.sockaddr_in = TranslateToSockAddrIn(addr);
+
+    return {std::move(result), Errno::SUCCESS};
+}
+
+Errno Socket::Connect(SockAddrIn addr_in) {
+    const sockaddr host_addr_in = TranslateFromSockAddrIn(addr_in);
+    if (connect(fd, &host_addr_in, sizeof(host_addr_in)) != SOCKET_ERROR) {
+        return Errno::SUCCESS;
+    }
+
+    return GetAndLogLastError();
+}
+
+std::pair<SockAddrIn, Errno> Socket::GetPeerName() {
+    sockaddr addr;
+    socklen_t addrlen = sizeof(addr);
+    if (getpeername(fd, &addr, &addrlen) == SOCKET_ERROR) {
+        return {SockAddrIn{}, GetAndLogLastError()};
+    }
+
+    ASSERT(addrlen == sizeof(sockaddr_in));
+    return {TranslateToSockAddrIn(addr), Errno::SUCCESS};
+}
+
+std::pair<SockAddrIn, Errno> Socket::GetSockName() {
+    sockaddr addr;
+    socklen_t addrlen = sizeof(addr);
+    if (getsockname(fd, &addr, &addrlen) == SOCKET_ERROR) {
+        return {SockAddrIn{}, GetAndLogLastError()};
+    }
+
+    ASSERT(addrlen == sizeof(sockaddr_in));
+    return {TranslateToSockAddrIn(addr), Errno::SUCCESS};
+}
+
+Errno Socket::Bind(SockAddrIn addr) {
+    const sockaddr addr_in = TranslateFromSockAddrIn(addr);
+    if (bind(fd, &addr_in, sizeof(addr_in)) != SOCKET_ERROR) {
+        return Errno::SUCCESS;
+    }
+
+    return GetAndLogLastError();
+}
+
+Errno Socket::Listen(s32 backlog) {
+    if (listen(fd, backlog) != SOCKET_ERROR) {
+        return Errno::SUCCESS;
+    }
+
+    return GetAndLogLastError();
+}
+
+Errno Socket::Shutdown(ShutdownHow how) {
+    int host_how = 0;
+    switch (how) {
+    case ShutdownHow::RD:
+        host_how = SD_RECEIVE;
+        break;
+    case ShutdownHow::WR:
+        host_how = SD_SEND;
+        break;
+    case ShutdownHow::RDWR:
+        host_how = SD_BOTH;
+        break;
+    default:
+        UNIMPLEMENTED_MSG("Unimplemented flag how={}", how);
+        return Errno::SUCCESS;
+    }
+    if (shutdown(fd, host_how) != SOCKET_ERROR) {
+        return Errno::SUCCESS;
+    }
+
+    return GetAndLogLastError();
+}
+
+std::pair<s32, Errno> Socket::Recv(int flags, std::vector<u8>& message) {
+    ASSERT(flags == 0);
+    ASSERT(message.size() < static_cast<size_t>(std::numeric_limits<int>::max()));
+
+    const auto result =
+        recv(fd, reinterpret_cast<char*>(message.data()), static_cast<int>(message.size()), 0);
+    if (result != SOCKET_ERROR) {
+        return {static_cast<s32>(result), Errno::SUCCESS};
+    }
+
+    return {-1, GetAndLogLastError()};
+}
+
+std::pair<s32, Errno> Socket::RecvFrom(int flags, std::vector<u8>& message, SockAddrIn* addr) {
+    ASSERT(flags == 0);
+    ASSERT(message.size() < static_cast<size_t>(std::numeric_limits<int>::max()));
+
+    sockaddr addr_in{};
+    socklen_t addrlen = sizeof(addr_in);
+    socklen_t* const p_addrlen = addr ? &addrlen : nullptr;
+    sockaddr* const p_addr_in = addr ? &addr_in : nullptr;
+
+    const auto result = recvfrom(fd, reinterpret_cast<char*>(message.data()),
+                                 static_cast<int>(message.size()), 0, p_addr_in, p_addrlen);
+    if (result != SOCKET_ERROR) {
+        if (addr) {
+            ASSERT(addrlen == sizeof(addr_in));
+            *addr = TranslateToSockAddrIn(addr_in);
+        }
+        return {static_cast<s32>(result), Errno::SUCCESS};
+    }
+
+    return {-1, GetAndLogLastError()};
+}
+
+std::pair<s32, Errno> Socket::Send(const std::vector<u8>& message, int flags) {
+    ASSERT(message.size() < static_cast<size_t>(std::numeric_limits<int>::max()));
+    ASSERT(flags == 0);
+
+    const auto result = send(fd, reinterpret_cast<const char*>(message.data()),
+                             static_cast<int>(message.size()), 0);
+    if (result != SOCKET_ERROR) {
+        return {static_cast<s32>(result), Errno::SUCCESS};
+    }
+
+    return {-1, GetAndLogLastError()};
+}
+
+std::pair<s32, Errno> Socket::SendTo(u32 flags, const std::vector<u8>& message,
+                                     const SockAddrIn* addr) {
+    ASSERT(flags == 0);
+
+    const sockaddr* to = nullptr;
+    const int tolen = addr ? sizeof(sockaddr) : 0;
+    sockaddr host_addr_in;
+
+    if (addr) {
+        host_addr_in = TranslateFromSockAddrIn(*addr);
+        to = &host_addr_in;
+    }
+
+    const auto result = sendto(fd, reinterpret_cast<const char*>(message.data()),
+                               static_cast<int>(message.size()), 0, to, tolen);
+    if (result != SOCKET_ERROR) {
+        return {static_cast<s32>(result), Errno::SUCCESS};
+    }
+
+    return {-1, GetAndLogLastError()};
+}
+
+Errno Socket::Close() {
+    [[maybe_unused]] const int result = closesocket(fd);
+    ASSERT(result == 0);
+    fd = INVALID_SOCKET;
+
+    return Errno::SUCCESS;
+}
+
+Errno Socket::SetLinger(bool enable, u32 linger) {
+    return SetSockOpt(fd, SO_LINGER, MakeLinger(enable, linger));
+}
+
+Errno Socket::SetReuseAddr(bool enable) {
+    return SetSockOpt<u32>(fd, SO_REUSEADDR, enable ? 1 : 0);
+}
+
+Errno Socket::SetKeepAlive(bool enable) {
+    return SetSockOpt<u32>(fd, SO_KEEPALIVE, enable ? 1 : 0);
+}
+
+Errno Socket::SetBroadcast(bool enable) {
+    return SetSockOpt<u32>(fd, SO_BROADCAST, enable ? 1 : 0);
+}
+
+Errno Socket::SetSndBuf(u32 value) {
+    return SetSockOpt(fd, SO_SNDBUF, value);
+}
+
+Errno Socket::SetRcvBuf(u32 value) {
+    return SetSockOpt(fd, SO_RCVBUF, value);
+}
+
+Errno Socket::SetSndTimeo(u32 value) {
+    return SetSockOpt(fd, SO_SNDTIMEO, value);
+}
+
+Errno Socket::SetRcvTimeo(u32 value) {
+    return SetSockOpt(fd, SO_RCVTIMEO, value);
+}
+
+Errno Socket::SetNonBlock(bool enable) {
+    if (EnableNonBlock(fd, enable)) {
+        return Errno::SUCCESS;
+    }
+    return GetAndLogLastError();
+}
+
+bool Socket::IsOpened() const {
+    return fd != INVALID_SOCKET;
+}
+
+} // namespace Network
diff --git a/src/core/internal_network/network.h b/src/core/internal_network/network.h
new file mode 100644
index 000000000..10e5ef10d
--- /dev/null
+++ b/src/core/internal_network/network.h
@@ -0,0 +1,117 @@
+// SPDX-FileCopyrightText: Copyright 2020 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <array>
+#include <optional>
+
+#include "common/common_funcs.h"
+#include "common/common_types.h"
+
+#ifdef _WIN32
+#include <winsock2.h>
+#elif YUZU_UNIX
+#include <netinet/in.h>
+#endif
+
+namespace Network {
+
+class Socket;
+
+/// Error code for network functions
+enum class Errno {
+    SUCCESS,
+    BADF,
+    INVAL,
+    MFILE,
+    NOTCONN,
+    AGAIN,
+    CONNREFUSED,
+    HOSTUNREACH,
+    NETDOWN,
+    NETUNREACH,
+    OTHER,
+};
+
+/// Address families
+enum class Domain {
+    INET, ///< Address family for IPv4
+};
+
+/// Socket types
+enum class Type {
+    STREAM,
+    DGRAM,
+    RAW,
+    SEQPACKET,
+};
+
+/// Protocol values for sockets
+enum class Protocol {
+    ICMP,
+    TCP,
+    UDP,
+};
+
+/// Shutdown mode
+enum class ShutdownHow {
+    RD,
+    WR,
+    RDWR,
+};
+
+/// Array of IPv4 address
+using IPv4Address = std::array<u8, 4>;
+
+/// Cross-platform sockaddr structure
+struct SockAddrIn {
+    Domain family;
+    IPv4Address ip;
+    u16 portno;
+};
+
+/// Cross-platform poll fd structure
+
+enum class PollEvents : u16 {
+    // Using Pascal case because IN is a macro on Windows.
+    In = 1 << 0,
+    Pri = 1 << 1,
+    Out = 1 << 2,
+    Err = 1 << 3,
+    Hup = 1 << 4,
+    Nval = 1 << 5,
+};
+
+DECLARE_ENUM_FLAG_OPERATORS(PollEvents);
+
+struct PollFD {
+    Socket* socket;
+    PollEvents events;
+    PollEvents revents;
+};
+
+class NetworkInstance {
+public:
+    explicit NetworkInstance();
+    ~NetworkInstance();
+};
+
+#ifdef _WIN32
+constexpr IPv4Address TranslateIPv4(in_addr addr) {
+    auto& bytes = addr.S_un.S_un_b;
+    return IPv4Address{bytes.s_b1, bytes.s_b2, bytes.s_b3, bytes.s_b4};
+}
+#elif YUZU_UNIX
+constexpr IPv4Address TranslateIPv4(in_addr addr) {
+    const u32 bytes = addr.s_addr;
+    return IPv4Address{static_cast<u8>(bytes), static_cast<u8>(bytes >> 8),
+                       static_cast<u8>(bytes >> 16), static_cast<u8>(bytes >> 24)};
+}
+#endif
+
+/// @brief Returns host's IPv4 address
+/// @return human ordered IPv4 address (e.g. 192.168.0.1) as an array
+std::optional<IPv4Address> GetHostIPv4Address();
+
+} // namespace Network
diff --git a/src/core/internal_network/network_interface.cpp b/src/core/internal_network/network_interface.cpp
new file mode 100644
index 000000000..0f0a66160
--- /dev/null
+++ b/src/core/internal_network/network_interface.cpp
@@ -0,0 +1,209 @@
+// SPDX-FileCopyrightText: Copyright 2021 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <algorithm>
+#include <fstream>
+#include <sstream>
+#include <vector>
+
+#include "common/bit_cast.h"
+#include "common/common_types.h"
+#include "common/logging/log.h"
+#include "common/settings.h"
+#include "common/string_util.h"
+#include "core/internal_network/network_interface.h"
+
+#ifdef _WIN32
+#include <iphlpapi.h>
+#else
+#include <cerrno>
+#include <ifaddrs.h>
+#include <net/if.h>
+#endif
+
+namespace Network {
+
+#ifdef _WIN32
+
+std::vector<NetworkInterface> GetAvailableNetworkInterfaces() {
+    std::vector<IP_ADAPTER_ADDRESSES> adapter_addresses;
+    DWORD ret = ERROR_BUFFER_OVERFLOW;
+    DWORD buf_size = 0;
+
+    // retry up to 5 times
+    for (int i = 0; i < 5 && ret == ERROR_BUFFER_OVERFLOW; i++) {
+        ret = GetAdaptersAddresses(
+            AF_INET, GAA_FLAG_SKIP_MULTICAST | GAA_FLAG_SKIP_DNS_SERVER | GAA_FLAG_INCLUDE_GATEWAYS,
+            nullptr, adapter_addresses.data(), &buf_size);
+
+        if (ret != ERROR_BUFFER_OVERFLOW) {
+            break;
+        }
+
+        adapter_addresses.resize((buf_size / sizeof(IP_ADAPTER_ADDRESSES)) + 1);
+    }
+
+    if (ret != NO_ERROR) {
+        LOG_ERROR(Network, "Failed to get network interfaces with GetAdaptersAddresses");
+        return {};
+    }
+
+    std::vector<NetworkInterface> result;
+
+    for (auto current_address = adapter_addresses.data(); current_address != nullptr;
+         current_address = current_address->Next) {
+        if (current_address->FirstUnicastAddress == nullptr ||
+            current_address->FirstUnicastAddress->Address.lpSockaddr == nullptr) {
+            continue;
+        }
+
+        if (current_address->OperStatus != IfOperStatusUp) {
+            continue;
+        }
+
+        const auto ip_addr = Common::BitCast<struct sockaddr_in>(
+                                 *current_address->FirstUnicastAddress->Address.lpSockaddr)
+                                 .sin_addr;
+
+        ULONG mask = 0;
+        if (ConvertLengthToIpv4Mask(current_address->FirstUnicastAddress->OnLinkPrefixLength,
+                                    &mask) != NO_ERROR) {
+            LOG_ERROR(Network, "Failed to convert IPv4 prefix length to subnet mask");
+            continue;
+        }
+
+        struct in_addr gateway = {.S_un{.S_addr{0}}};
+        if (current_address->FirstGatewayAddress != nullptr &&
+            current_address->FirstGatewayAddress->Address.lpSockaddr != nullptr) {
+            gateway = Common::BitCast<struct sockaddr_in>(
+                          *current_address->FirstGatewayAddress->Address.lpSockaddr)
+                          .sin_addr;
+        }
+
+        result.emplace_back(NetworkInterface{
+            .name{Common::UTF16ToUTF8(std::wstring{current_address->FriendlyName})},
+            .ip_address{ip_addr},
+            .subnet_mask = in_addr{.S_un{.S_addr{mask}}},
+            .gateway = gateway});
+    }
+
+    return result;
+}
+
+#else
+
+std::vector<NetworkInterface> GetAvailableNetworkInterfaces() {
+    struct ifaddrs* ifaddr = nullptr;
+
+    if (getifaddrs(&ifaddr) != 0) {
+        LOG_ERROR(Network, "Failed to get network interfaces with getifaddrs: {}",
+                  std::strerror(errno));
+        return {};
+    }
+
+    std::vector<NetworkInterface> result;
+
+    for (auto ifa = ifaddr; ifa != nullptr; ifa = ifa->ifa_next) {
+        if (ifa->ifa_addr == nullptr || ifa->ifa_netmask == nullptr) {
+            continue;
+        }
+
+        if (ifa->ifa_addr->sa_family != AF_INET) {
+            continue;
+        }
+
+        if ((ifa->ifa_flags & IFF_UP) == 0 || (ifa->ifa_flags & IFF_LOOPBACK) != 0) {
+            continue;
+        }
+
+        u32 gateway{};
+
+        std::ifstream file{"/proc/net/route"};
+        if (!file.is_open()) {
+            LOG_ERROR(Network, "Failed to open \"/proc/net/route\"");
+
+            result.emplace_back(NetworkInterface{
+                .name{ifa->ifa_name},
+                .ip_address{Common::BitCast<struct sockaddr_in>(*ifa->ifa_addr).sin_addr},
+                .subnet_mask{Common::BitCast<struct sockaddr_in>(*ifa->ifa_netmask).sin_addr},
+                .gateway{in_addr{.s_addr = gateway}}});
+            continue;
+        }
+
+        // ignore header
+        file.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
+
+        bool gateway_found = false;
+
+        for (std::string line; std::getline(file, line);) {
+            std::istringstream iss{line};
+
+            std::string iface_name;
+            iss >> iface_name;
+            if (iface_name != ifa->ifa_name) {
+                continue;
+            }
+
+            iss >> std::hex;
+
+            u32 dest{};
+            iss >> dest;
+            if (dest != 0) {
+                // not the default route
+                continue;
+            }
+
+            iss >> gateway;
+
+            u16 flags{};
+            iss >> flags;
+
+            // flag RTF_GATEWAY (defined in <linux/route.h>)
+            if ((flags & 0x2) == 0) {
+                continue;
+            }
+
+            gateway_found = true;
+            break;
+        }
+
+        if (!gateway_found) {
+            gateway = 0;
+        }
+
+        result.emplace_back(NetworkInterface{
+            .name{ifa->ifa_name},
+            .ip_address{Common::BitCast<struct sockaddr_in>(*ifa->ifa_addr).sin_addr},
+            .subnet_mask{Common::BitCast<struct sockaddr_in>(*ifa->ifa_netmask).sin_addr},
+            .gateway{in_addr{.s_addr = gateway}}});
+    }
+
+    freeifaddrs(ifaddr);
+
+    return result;
+}
+
+#endif
+
+std::optional<NetworkInterface> GetSelectedNetworkInterface() {
+    const auto& selected_network_interface = Settings::values.network_interface.GetValue();
+    const auto network_interfaces = Network::GetAvailableNetworkInterfaces();
+    if (network_interfaces.size() == 0) {
+        LOG_ERROR(Network, "GetAvailableNetworkInterfaces returned no interfaces");
+        return std::nullopt;
+    }
+
+    const auto res =
+        std::ranges::find_if(network_interfaces, [&selected_network_interface](const auto& iface) {
+            return iface.name == selected_network_interface;
+        });
+
+    if (res == network_interfaces.end()) {
+        LOG_ERROR(Network, "Couldn't find selected interface \"{}\"", selected_network_interface);
+        return std::nullopt;
+    }
+
+    return *res;
+}
+
+} // namespace Network
diff --git a/src/core/internal_network/network_interface.h b/src/core/internal_network/network_interface.h
new file mode 100644
index 000000000..9b98b6b42
--- /dev/null
+++ b/src/core/internal_network/network_interface.h
@@ -0,0 +1,28 @@
+// SPDX-FileCopyrightText: Copyright 2021 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <optional>
+#include <string>
+#include <vector>
+
+#ifdef _WIN32
+#include <winsock2.h>
+#else
+#include <netinet/in.h>
+#endif
+
+namespace Network {
+
+struct NetworkInterface {
+    std::string name;
+    struct in_addr ip_address;
+    struct in_addr subnet_mask;
+    struct in_addr gateway;
+};
+
+std::vector<NetworkInterface> GetAvailableNetworkInterfaces();
+std::optional<NetworkInterface> GetSelectedNetworkInterface();
+
+} // namespace Network
diff --git a/src/core/internal_network/sockets.h b/src/core/internal_network/sockets.h
new file mode 100644
index 000000000..77e27e928
--- /dev/null
+++ b/src/core/internal_network/sockets.h
@@ -0,0 +1,95 @@
+// SPDX-FileCopyrightText: Copyright 2020 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <map>
+#include <memory>
+#include <utility>
+
+#if defined(_WIN32)
+#elif !YUZU_UNIX
+#error "Platform not implemented"
+#endif
+
+#include "common/common_types.h"
+#include "core/internal_network/network.h"
+
+// TODO: C++20 Replace std::vector usages with std::span
+
+namespace Network {
+
+class Socket {
+public:
+    struct AcceptResult {
+        std::unique_ptr<Socket> socket;
+        SockAddrIn sockaddr_in;
+    };
+
+    explicit Socket() = default;
+    ~Socket();
+
+    Socket(const Socket&) = delete;
+    Socket& operator=(const Socket&) = delete;
+
+    Socket(Socket&& rhs) noexcept;
+
+    // Avoid closing sockets implicitly
+    Socket& operator=(Socket&&) noexcept = delete;
+
+    Errno Initialize(Domain domain, Type type, Protocol protocol);
+
+    Errno Close();
+
+    std::pair<AcceptResult, Errno> Accept();
+
+    Errno Connect(SockAddrIn addr_in);
+
+    std::pair<SockAddrIn, Errno> GetPeerName();
+
+    std::pair<SockAddrIn, Errno> GetSockName();
+
+    Errno Bind(SockAddrIn addr);
+
+    Errno Listen(s32 backlog);
+
+    Errno Shutdown(ShutdownHow how);
+
+    std::pair<s32, Errno> Recv(int flags, std::vector<u8>& message);
+
+    std::pair<s32, Errno> RecvFrom(int flags, std::vector<u8>& message, SockAddrIn* addr);
+
+    std::pair<s32, Errno> Send(const std::vector<u8>& message, int flags);
+
+    std::pair<s32, Errno> SendTo(u32 flags, const std::vector<u8>& message, const SockAddrIn* addr);
+
+    Errno SetLinger(bool enable, u32 linger);
+
+    Errno SetReuseAddr(bool enable);
+
+    Errno SetKeepAlive(bool enable);
+
+    Errno SetBroadcast(bool enable);
+
+    Errno SetSndBuf(u32 value);
+
+    Errno SetRcvBuf(u32 value);
+
+    Errno SetSndTimeo(u32 value);
+
+    Errno SetRcvTimeo(u32 value);
+
+    Errno SetNonBlock(bool enable);
+
+    bool IsOpened() const;
+
+#if defined(_WIN32)
+    SOCKET fd = INVALID_SOCKET;
+#elif YUZU_UNIX
+    int fd = -1;
+#endif
+};
+
+std::pair<s32, Errno> Poll(std::vector<PollFD>& poll_fds, s32 timeout);
+
+} // namespace Network