4 files changed, 285 insertions, 35 deletions

diff --git a/src/core/network/network.cpp b/src/core/network/network.cpp
index 375bc79ec..4732d4485 100644
--- a/src/core/network/network.cpp
+++ b/src/core/network/network.cpp
@@ -10,9 +10,10 @@
 #include "common/common_funcs.h"
 
 #ifdef _WIN32
-#define _WINSOCK_DEPRECATED_NO_WARNINGS // gethostname
 #include <winsock2.h>
+#include <ws2tcpip.h>
 #elif YUZU_UNIX
+#include <arpa/inet.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <netdb.h>
@@ -27,7 +28,9 @@
 #include "common/assert.h"
 #include "common/common_types.h"
 #include "common/logging/log.h"
+#include "common/settings.h"
 #include "core/network/network.h"
+#include "core/network/network_interface.h"
 #include "core/network/sockets.h"
 
 namespace Network {
@@ -47,11 +50,6 @@ 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;
 
@@ -138,12 +136,6 @@ 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;
 
@@ -182,7 +174,7 @@ linger MakeLinger(bool enable, u32 linger_value) {
 }
 
 bool EnableNonBlock(int fd, bool enable) {
-    int flags = fcntl(fd, F_GETFD);
+    int flags = fcntl(fd, F_GETFL);
     if (flags == -1) {
         return false;
     }
@@ -191,7 +183,7 @@ bool EnableNonBlock(int fd, bool enable) {
     } else {
         flags &= ~O_NONBLOCK;
     }
-    return fcntl(fd, F_SETFD, flags) == 0;
+    return fcntl(fd, F_SETFL, flags) == 0;
 }
 
 Errno TranslateNativeError(int e) {
@@ -227,8 +219,12 @@ Errno GetAndLogLastError() {
 #else
     int e = errno;
 #endif
+    const Errno err = TranslateNativeError(e);
+    if (err == Errno::AGAIN) {
+        return err;
+    }
     LOG_ERROR(Network, "Socket operation error: {}", NativeErrorToString(e));
-    return TranslateNativeError(e);
+    return err;
 }
 
 int TranslateDomain(Domain domain) {
@@ -353,27 +349,29 @@ 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) {
-        return {IPv4Address{}, GetAndLogLastError()};
+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 {};
     }
 
-    hostent* const ent = gethostbyname(name.data());
-    if (!ent) {
-        return {IPv4Address{}, GetAndLogLastError()};
-    }
-    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);
-    }
+    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);
+        LOG_INFO(Network, "IP address: {}", ip_addr);
 
-    in_addr addr;
-    std::memcpy(&addr, ent->h_addr_list[0], sizeof(addr));
-    return {TranslateIPv4(addr), Errno::SUCCESS};
+        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) {
diff --git a/src/core/network/network.h b/src/core/network/network.h
index bd30f1899..fdd3e4655 100644
--- a/src/core/network/network.h
+++ b/src/core/network/network.h
@@ -5,11 +5,18 @@
 #pragma once
 
 #include <array>
+#include <optional>
 #include <utility>
 
 #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;
@@ -92,8 +99,21 @@ public:
     ~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 Pair of an array of human ordered IPv4 address (e.g. 192.168.0.1) and an error code
-std::pair<IPv4Address, Errno> GetHostIPv4Address();
+/// @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/network/network_interface.cpp b/src/core/network/network_interface.cpp
new file mode 100644
index 000000000..cecc9aa11
--- /dev/null
+++ b/src/core/network/network_interface.cpp
@@ -0,0 +1,203 @@
+// Copyright 2021 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#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/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) {
+            adapter_addresses.resize((buf_size / sizeof(IP_ADAPTER_ADDRESSES)) + 1);
+        } else {
+            break;
+        }
+    }
+
+    if (ret == NO_ERROR) {
+        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.push_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 {
+        LOG_ERROR(Network, "Failed to get network interfaces with GetAdaptersAddresses");
+        return {};
+    }
+}
+
+#else
+
+std::vector<NetworkInterface> GetAvailableNetworkInterfaces() {
+    std::vector<NetworkInterface> result;
+
+    struct ifaddrs* ifaddr = nullptr;
+
+    if (getifaddrs(&ifaddr) != 0) {
+        LOG_ERROR(Network, "Failed to get network interfaces with getifaddrs: {}",
+                  std::strerror(errno));
+        return 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;
+        }
+
+        std::uint32_t gateway{0};
+        std::ifstream file{"/proc/net/route"};
+        if (file.is_open()) {
+
+            // 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;
+
+                std::uint32_t dest{0};
+                iss >> dest;
+                if (dest != 0) {
+                    // not the default route
+                    continue;
+                }
+
+                iss >> gateway;
+
+                std::uint16_t flags{0};
+                iss >> flags;
+
+                // flag RTF_GATEWAY (defined in <linux/route.h>)
+                if ((flags & 0x2) == 0) {
+                    continue;
+                }
+
+                gateway_found = true;
+                break;
+            }
+
+            if (!gateway_found) {
+                gateway = 0;
+            }
+        } else {
+            LOG_ERROR(Network, "Failed to open \"/proc/net/route\"");
+        }
+
+        result.push_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 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()) {
+        return *res;
+    } else {
+        LOG_ERROR(Network, "Couldn't find selected interface \"{}\"", selected_network_interface);
+        return {};
+    }
+}
+
+} // namespace Network
diff --git a/src/core/network/network_interface.h b/src/core/network/network_interface.h
new file mode 100644
index 000000000..980edb2f5
--- /dev/null
+++ b/src/core/network/network_interface.h
@@ -0,0 +1,29 @@
+// Copyright 2021 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#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