5 files changed, 840 insertions, 0 deletions

diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
index c42f95705..c85c9485f 100644
--- a/src/core/CMakeLists.txt
+++ b/src/core/CMakeLists.txt
@@ -586,6 +586,9 @@ add_library(core STATIC
     memory/dmnt_cheat_vm.h
     memory.cpp
     memory.h
+    network/network.cpp
+    network/network.h
+    network/sockets.h
     perf_stats.cpp
     perf_stats.h
     reporter.cpp
diff --git a/src/core/core.cpp b/src/core/core.cpp
index 69a1aa0a5..e598c0e2b 100644
--- a/src/core/core.cpp
+++ b/src/core/core.cpp
@@ -43,6 +43,7 @@
 #include "core/loader/loader.h"
 #include "core/memory.h"
 #include "core/memory/cheat_engine.h"
+#include "core/network/network.h"
 #include "core/perf_stats.h"
 #include "core/reporter.h"
 #include "core/settings.h"
@@ -394,6 +395,9 @@ struct System::Impl {
     /// Telemetry session for this emulation session
     std::unique_ptr<Core::TelemetrySession> telemetry_session;
 
+    /// Network instance
+    Network::NetworkInstance network_instance;
+
     ResultStatus status = ResultStatus::Success;
     std::string status_details = "";
 
diff --git a/src/core/network/network.cpp b/src/core/network/network.cpp
new file mode 100644
index 000000000..fb21b0a47
--- /dev/null
+++ b/src/core/network/network.cpp
@@ -0,0 +1,652 @@
+// Copyright 2020 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <algorithm>
+#include <cstring>
+#include <limits>
+#include <utility>
+#include <vector>
+
+#ifdef _WIN32
+#define _WINSOCK_DEPRECATED_NO_WARNINGS // gethostname
+#include <winsock2.h>
+#elif __unix__
+#include <errno.h>
+#include <fcntl.h>
+#include <netdb.h>
+#include <poll.h>
+#include <unistd.h>
+#else
+#error "Unimplemented platform"
+#endif
+
+#include "common/assert.h"
+#include "common/common_types.h"
+#include "common/logging/log.h"
+#include "core/network/network.h"
+#include "core/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();
+}
+
+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};
+}
+
+sockaddr TranslateFromSockAddrIn(SockAddrIn input) {
+    sockaddr_in result;
+
+#ifdef __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={}", static_cast<int>(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;
+}
+
+int LastError() {
+    return WSAGetLastError();
+}
+
+bool EnableNonBlock(SOCKET fd, bool enable) {
+    u_long value = enable ? 1 : 0;
+    return ioctlsocket(fd, FIONBIO, &value) != SOCKET_ERROR;
+}
+
+#elif __unix__ // ^ _WIN32 v __unix__
+
+using SOCKET = int;
+using WSAPOLLFD = pollfd;
+using ULONG = u64;
+
+constexpr SOCKET INVALID_SOCKET = -1;
+constexpr SOCKET SOCKET_ERROR = -1;
+
+constexpr int WSAEWOULDBLOCK = EAGAIN;
+constexpr int WSAENOTCONN = ENOTCONN;
+
+constexpr int SD_RECEIVE = SHUT_RD;
+constexpr int SD_SEND = SHUT_WR;
+constexpr int SD_BOTH = SHUT_RDWR;
+
+void Initialize() {}
+
+void Finalize() {}
+
+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)};
+}
+
+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={}", static_cast<int>(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, 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;
+}
+
+int LastError() {
+    return errno;
+}
+
+bool EnableNonBlock(int fd, bool enable) {
+    int flags = fcntl(fd, F_GETFD);
+    if (flags == -1) {
+        return false;
+    }
+    if (enable) {
+        flags |= O_NONBLOCK;
+    } else {
+        flags &= ~O_NONBLOCK;
+    }
+    return fcntl(fd, F_SETFD, flags) == 0;
+}
+
+#endif
+
+int TranslateDomain(Domain domain) {
+    switch (domain) {
+    case Domain::INET:
+        return AF_INET;
+    default:
+        UNIMPLEMENTED_MSG("Unimplemented domain={}", static_cast<int>(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={}", static_cast<int>(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={}", static_cast<int>(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;
+}
+
+u16 TranslatePollEvents(u16 events) {
+    u16 result = 0;
+
+    if (events & POLL_IN) {
+        events &= ~POLL_IN;
+        result |= POLLIN;
+    }
+    if (events & POLL_PRI) {
+        events &= ~POLL_PRI;
+#ifdef _WIN32
+        LOG_WARNING(Service, "Winsock doesn't support POLLPRI");
+#else
+        result |= POLL_PRI;
+#endif
+    }
+    if (events & POLL_OUT) {
+        events &= ~POLL_OUT;
+        result |= POLLOUT;
+    }
+
+    UNIMPLEMENTED_IF_MSG(events != 0, "Unhandled guest events=0x{:x}", events);
+
+    return result;
+}
+
+u16 TranslatePollRevents(u16 revents) {
+    u16 result = 0;
+    const auto translate = [&result, &revents](int host, unsigned guest) {
+        if (revents & host) {
+            revents &= ~host;
+            result |= guest;
+        }
+    };
+
+    translate(POLLIN, POLL_IN);
+    translate(POLLPRI, POLL_PRI);
+    translate(POLLOUT, POLL_OUT);
+    translate(POLLERR, POLL_ERR);
+    translate(POLLHUP, POLL_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;
+    }
+    const int ec = LastError();
+    UNREACHABLE_MSG("Unhandled host socket error={}", ec);
+    return Errno::SUCCESS;
+}
+
+} // Anonymous namespace
+
+NetworkInstance::NetworkInstance() {
+    Initialize();
+}
+
+NetworkInstance::~NetworkInstance() {
+    Finalize();
+}
+
+std::pair<IPv4Address, Errno> GetHostIPv4Address() {
+    std::array<char, 256> name{};
+    if (gethostname(name.data(), static_cast<int>(name.size()) - 1) == SOCKET_ERROR) {
+        UNIMPLEMENTED_MSG("Unhandled gethostname error");
+        return {IPv4Address{}, Errno::SUCCESS};
+    }
+
+    hostent* const ent = gethostbyname(name.data());
+    if (!ent) {
+        UNIMPLEMENTED_MSG("Unhandled gethostbyname error");
+        return {IPv4Address{}, Errno::SUCCESS};
+    }
+    if (ent->h_addr_list == nullptr) {
+        UNIMPLEMENTED_MSG("No addr provided in hostent->h_addr_list");
+        return {IPv4Address{}, Errno::SUCCESS};
+    }
+    if (ent->h_length != sizeof(in_addr)) {
+        UNIMPLEMENTED_MSG("Unexpected size={} in hostent->h_length", ent->h_length);
+    }
+
+    in_addr addr;
+    std::memcpy(&addr, ent->h_addr_list[0], sizeof(addr));
+    return {TranslateIPv4(addr), Errno::SUCCESS};
+}
+
+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);
+
+    const int ec = LastError();
+    UNREACHABLE_MSG("Unhandled host socket error={}", ec);
+    return {-1, Errno::SUCCESS};
+}
+
+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;
+    }
+
+    const int ec = LastError();
+    UNREACHABLE_MSG("Unhandled host socket error={}", ec);
+    return Errno::SUCCESS;
+}
+
+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) {
+        const int ec = LastError();
+        UNREACHABLE_MSG("Unhandled host socket error={}", ec);
+        return {AcceptResult{}, Errno::SUCCESS};
+    }
+
+    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)) != INVALID_SOCKET) {
+        return Errno::SUCCESS;
+    }
+
+    switch (const int ec = LastError()) {
+    case WSAEWOULDBLOCK:
+        LOG_DEBUG(Service, "EAGAIN generated");
+        return Errno::AGAIN;
+    default:
+        UNREACHABLE_MSG("Unhandled host socket error={}", ec);
+        return Errno::SUCCESS;
+    }
+}
+
+std::pair<SockAddrIn, Errno> Socket::GetPeerName() {
+    sockaddr addr;
+    socklen_t addrlen = sizeof(addr);
+    if (getpeername(fd, &addr, &addrlen) == SOCKET_ERROR) {
+        const int ec = LastError();
+        UNREACHABLE_MSG("Unhandled host socket error={}", ec);
+        return {SockAddrIn{}, Errno::SUCCESS};
+    }
+
+    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) {
+        const int ec = LastError();
+        UNREACHABLE_MSG("Unhandled host socket error={}", ec);
+        return {SockAddrIn{}, Errno::SUCCESS};
+    }
+
+    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;
+    }
+
+    const int ec = LastError();
+    UNREACHABLE_MSG("Unhandled host socket error={}", ec);
+    return Errno::SUCCESS;
+}
+
+Errno Socket::Listen(s32 backlog) {
+    if (listen(fd, backlog) != SOCKET_ERROR) {
+        return Errno::SUCCESS;
+    }
+
+    const int ec = LastError();
+    UNREACHABLE_MSG("Unhandled host socket error={}", ec);
+    return Errno::SUCCESS;
+}
+
+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={}", static_cast<int>(how));
+        return Errno::SUCCESS;
+    }
+    if (shutdown(fd, host_how) != SOCKET_ERROR) {
+        return Errno::SUCCESS;
+    }
+
+    switch (const int ec = LastError()) {
+    case WSAENOTCONN:
+        LOG_ERROR(Service, "ENOTCONN generated");
+        return Errno::NOTCONN;
+    default:
+        UNREACHABLE_MSG("Unhandled host socket error={}", ec);
+        return Errno::SUCCESS;
+    }
+}
+
+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 int result =
+        recv(fd, reinterpret_cast<char*>(message.data()), static_cast<int>(message.size()), 0);
+    if (result != SOCKET_ERROR) {
+        return {result, Errno::SUCCESS};
+    }
+
+    switch (const int ec = LastError()) {
+    case WSAEWOULDBLOCK:
+        LOG_DEBUG(Service, "EAGAIN generated");
+        return {-1, Errno::AGAIN};
+    case WSAENOTCONN:
+        LOG_ERROR(Service, "ENOTCONN generated");
+        return {-1, Errno::NOTCONN};
+    default:
+        UNREACHABLE_MSG("Unhandled host socket error={}", ec);
+        return {0, Errno::SUCCESS};
+    }
+}
+
+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 int 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 {result, Errno::SUCCESS};
+    }
+
+    switch (const int ec = LastError()) {
+    case WSAEWOULDBLOCK:
+        LOG_DEBUG(Service, "EAGAIN generated");
+        return {-1, Errno::AGAIN};
+    case WSAENOTCONN:
+        LOG_ERROR(Service, "ENOTCONN generated");
+        return {-1, Errno::NOTCONN};
+    default:
+        UNREACHABLE_MSG("Unhandled host socket error={}", ec);
+        return {-1, Errno::SUCCESS};
+    }
+}
+
+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 int result = send(fd, reinterpret_cast<const char*>(message.data()),
+                            static_cast<int>(message.size()), 0);
+    if (result != SOCKET_ERROR) {
+        return {result, Errno::SUCCESS};
+    }
+
+    const int ec = LastError();
+    switch (ec) {
+    case WSAEWOULDBLOCK:
+        LOG_DEBUG(Service, "EAGAIN generated");
+        return {-1, Errno::AGAIN};
+    case WSAENOTCONN:
+        LOG_ERROR(Service, "ENOTCONN generated");
+        return {-1, Errno::NOTCONN};
+    default:
+        UNREACHABLE_MSG("Unhandled host socket error={}", ec);
+        return {-1, Errno::SUCCESS};
+    }
+}
+
+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 ? 0 : sizeof(sockaddr);
+    sockaddr host_addr_in;
+
+    if (addr) {
+        host_addr_in = TranslateFromSockAddrIn(*addr);
+        to = &host_addr_in;
+    }
+
+    const int result = sendto(fd, reinterpret_cast<const char*>(message.data()),
+                              static_cast<int>(message.size()), 0, to, tolen);
+    if (result != SOCKET_ERROR) {
+        return {result, Errno::SUCCESS};
+    }
+
+    const int ec = LastError();
+    UNREACHABLE_MSG("Unhandled host socket error={}", ec);
+    return {-1, Errno::SUCCESS};
+}
+
+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::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;
+    }
+    const int ec = LastError();
+    UNREACHABLE_MSG("Unhandled host socket error={}", ec);
+    return Errno::SUCCESS;
+}
+
+bool Socket::IsOpened() const {
+    return fd != INVALID_SOCKET;
+}
+
+} // namespace Network
diff --git a/src/core/network/network.h b/src/core/network/network.h
new file mode 100644
index 000000000..0622e4593
--- /dev/null
+++ b/src/core/network/network.h
@@ -0,0 +1,87 @@
+// Copyright 2020 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <array>
+#include <utility>
+
+#include "common/common_types.h"
+
+namespace Network {
+
+class Socket;
+
+/// Error code for network functions
+enum class Errno {
+    SUCCESS,
+    BADF,
+    INVAL,
+    MFILE,
+    NOTCONN,
+    AGAIN,
+};
+
+/// 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
+struct PollFD {
+    Socket* socket;
+    u16 events;
+    u16 revents;
+};
+
+constexpr u16 POLL_IN = 1 << 0;
+constexpr u16 POLL_PRI = 1 << 1;
+constexpr u16 POLL_OUT = 1 << 2;
+constexpr u16 POLL_ERR = 1 << 3;
+constexpr u16 POLL_HUP = 1 << 4;
+constexpr u16 POLL_NVAL = 1 << 5;
+
+class NetworkInstance {
+public:
+    explicit NetworkInstance();
+    ~NetworkInstance();
+};
+
+/// @brief Returns host's IPv4 address
+/// @return Pair of an array of human ordered IPv4 address (e.g. 192.168.0.1) and an error code
+std::pair<IPv4Address, Errno> GetHostIPv4Address();
+
+} // namespace Network
diff --git a/src/core/network/sockets.h b/src/core/network/sockets.h
new file mode 100644
index 000000000..7bdff0fe4
--- /dev/null
+++ b/src/core/network/sockets.h
@@ -0,0 +1,94 @@
+// Copyright 2020 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <memory>
+#include <utility>
+
+#if defined(_WIN32)
+#include <winsock.h>
+#elif !defined(__unix__)
+#error "Platform not implemented"
+#endif
+
+#include "common/common_types.h"
+#include "core/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 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 defined(__unix__)
+    int fd = -1;
+#endif
+};
+
+std::pair<s32, Errno> Poll(std::vector<PollFD>& poll_fds, s32 timeout);
+
+} // namespace Network