4 files changed, 164 insertions, 22 deletions

diff --git a/src/core/network/network.cpp b/src/core/network/network.cpp
index 7b038041e..67ecf57bd 100644
--- a/src/core/network/network.cpp
+++ b/src/core/network/network.cpp
@@ -10,8 +10,8 @@
 #include "common/common_funcs.h"
 
 #ifdef _WIN32
-#define _WINSOCK_DEPRECATED_NO_WARNINGS // gethostname
 #include <winsock2.h>
+#include <ws2tcpip.h>
 #elif YUZU_UNIX
 #include <errno.h>
 #include <fcntl.h>
@@ -19,6 +19,7 @@
 #include <netinet/in.h>
 #include <poll.h>
 #include <sys/socket.h>
+#include <arpa/inet.h>
 #include <unistd.h>
 #else
 #error "Unimplemented platform"
@@ -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 {
@@ -357,27 +360,27 @@ 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();
+    ASSERT_MSG(network_interfaces.size() > 0, "GetAvailableNetworkInterfaces returned no interfaces");
 
-    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);
-    }
 
-    in_addr addr;
-    std::memcpy(&addr, ent->h_addr_list[0], sizeof(addr));
-    return {TranslateIPv4(addr), Errno::SUCCESS};
+    const auto res = std::ranges::find_if(network_interfaces,
+                                          [&selected_network_interface](const auto& interface) {
+                                              return interface.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);
+
+        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..cfa68d478 100644
--- a/src/core/network/network.h
+++ b/src/core/network/network.h
@@ -5,6 +5,7 @@
 #pragma once
 
 #include <array>
+#include <optional>
 #include <utility>
 
 #include "common/common_funcs.h"
@@ -93,7 +94,7 @@ public:
 };
 
 /// @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..bba4c8b26
--- /dev/null
+++ b/src/core/network/network_interface.cpp
@@ -0,0 +1,113 @@
+// Copyright 2021 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <vector>
+
+#include "common/common_types.h"
+#include "common/logging/log.h"
+#include "common/string_util.h"
+#include "core/network/network_interface.h"
+
+#ifdef _WIN32
+#include <iphlpapi.h>
+#else
+#include <ifaddrs.h>
+#include <net/if.h>
+#include <cerrno>
+#endif
+
+namespace Network {
+
+#ifdef _WIN32
+
+std::vector<NetworkInterface> GetAvailableNetworkInterfaces() {
+    std::vector<NetworkInterface> result;
+
+    std::vector<u8> adapter_addresses_raw;
+    auto adapter_addresses = reinterpret_cast<PIP_ADAPTER_ADDRESSES>(adapter_addresses_raw.data());
+    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,
+                                   nullptr, adapter_addresses, &buf_size);
+
+        if (ret == ERROR_BUFFER_OVERFLOW) {
+            adapter_addresses_raw.resize(buf_size);
+            adapter_addresses =
+                reinterpret_cast<PIP_ADAPTER_ADDRESSES>(adapter_addresses_raw.data());
+        } else {
+            break;
+        }
+    }
+
+    if (ret == NO_ERROR) {
+        for (auto current_address = adapter_addresses; 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 = std::bit_cast<struct sockaddr_in>(
+                                     *current_address->FirstUnicastAddress->Address.lpSockaddr)
+                                     .sin_addr;
+
+            result.push_back(NetworkInterface{
+                .name{Common::UTF16ToUTF8(std::wstring{current_address->FriendlyName})},
+                .ip_address{ip_addr}
+            });
+        }
+    } else {
+        LOG_ERROR(Network, "Failed to get network interfaces with GetAdaptersAddresses");
+    }
+
+    return result;
+}
+
+#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) {
+            continue;
+        }
+
+        if (ifa->ifa_addr->sa_family != AF_INET) {
+            continue;
+        }
+
+        if (!(ifa->ifa_flags & IFF_UP) || ifa->ifa_flags & IFF_LOOPBACK) {
+            continue;
+        }
+
+        result.push_back(NetworkInterface{
+            .name{ifa->ifa_name},
+            .ip_address{std::bit_cast<struct sockaddr_in>(*ifa->ifa_addr).sin_addr}
+        });
+    }
+
+    freeifaddrs(ifaddr);
+
+    return result;
+}
+
+#endif
+
+} // namespace Network
diff --git a/src/core/network/network_interface.h b/src/core/network/network_interface.h
new file mode 100644
index 000000000..d7184e14a
--- /dev/null
+++ b/src/core/network/network_interface.h
@@ -0,0 +1,25 @@
+// Copyright 2021 yuzu emulator team
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#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;
+};
+
+std::vector<NetworkInterface> GetAvailableNetworkInterfaces();
+
+} // namespace Network