Version 5.4

This is a violation of the UPnP IGD specification but we can relay through an alternate port as a workaround.

mish/Product.wxs

@@ -14,6 +14,28 @@
     </Feature>
   </Product>
 
+  <!-- Enable the Windows Firewall service if it is disabled. Disabling the Windows Firewall service
+       will paradoxically block *all* incoming network traffic and prevent GameStream, MIST, MISS,
+       and other local servers from working at all. The proper way to disable Windows Firewall is via
+       the Windows Firewall control panel applet. -->
+  <Fragment>
+    <Property Id="MPSSVC_START">
+      <RegistrySearch Id="MpsSvcStart"
+                      Root="HKLM"
+                      Key="System\CurrentControlSet\Services\MpsSvc"
+                      Name="Start"
+                      Type="raw" />
+    </Property>
+
+    <SetProperty Id="EnableMpsSvc" Value='"[SystemFolder]sc.exe" config MpsSvc start= auto' Sequence="execute" Before="InstallInitialize"/>
+    <CustomAction Id="EnableMpsSvc" BinaryKey="WixCA" DllEntry="WixQuietExec"
+                  Execute="deferred" Return="ignore" Impersonate="no"/>
+
+    <SetProperty Id="StartMpsSvc" Value='"[SystemFolder]net.exe" start MpsSvc' Sequence="execute" Before="InstallInitialize"/>
+    <CustomAction Id="StartMpsSvc" BinaryKey="WixCA" DllEntry="WixQuietExec"
+                  Execute="deferred" Return="ignore" Impersonate="no"/>
+  </Fragment>
+  
   <Fragment>
     <Directory Id="TARGETDIR" Name="SourceDir">
       <Directory Id="ProgramFilesFolder">
@@ -47,9 +69,8 @@
                         Account="NT AUTHORITY\LocalService"
                         ErrorControl="ignore"
                         Interactive="no">
-          <ServiceConfig DelayedAutoStart="no" OnInstall="yes" OnReinstall="yes" ServiceSid="restricted">
-            <RequiredPrivilege>SeChangeNotifyPrivilege</RequiredPrivilege>
-          </ServiceConfig>
+          <ServiceConfig DelayedAutoStart="no" OnInstall="yes" OnReinstall="yes" ServiceSid="unrestricted"/>
+          <util:ServiceConfig FirstFailureActionType="restart" SecondFailureActionType="restart" ThirdFailureActionType="restart" ResetPeriodInDays="1" RestartServiceDelayInSeconds="10"/>
         </ServiceInstall>
         <ServiceControl Id="StartService" Start="install" Stop="both" Remove="uninstall" Name="MISS" Wait="yes" />
       </Component>
@@ -60,6 +81,43 @@
                                   Name="Moonlight Internet Streaming Tester"/>
         </File>
       </Component>
+      <Component Id="GameStreamFirewallRules" Guid="{16CA2511-B533-46F8-8882-F8AEEFDFD7DF}" KeyPath="yes">
+        <fire:FirewallException Id="HttpsFwException"
+                                Scope="any"
+                                Port="47984"
+                                Protocol="tcp"
+                                Name="Moonlight - HTTPS"/>
+        <fire:FirewallException Id="HttpFwException"
+                                Scope="any"
+                                Port="47989"
+                                Protocol="tcp"
+                                Name="Moonlight - HTTP"/>
+        <fire:FirewallException Id="RtspFwException"
+                                Scope="any"
+                                Port="48010"
+                                Protocol="tcp"
+                                Name="Moonlight - RTSP"/>
+        <fire:FirewallException Id="VideoFwException"
+                                Scope="any"
+                                Port="47998"
+                                Protocol="udp"
+                                Name="Moonlight - Video"/>
+        <fire:FirewallException Id="ControlFwException"
+                                Scope="any"
+                                Port="47999"
+                                Protocol="udp"
+                                Name="Moonlight - Control"/>
+        <fire:FirewallException Id="AudioFwException"
+                                Scope="any"
+                                Port="48000"
+                                Protocol="udp"
+                                Name="Moonlight - Audio"/>
+        <fire:FirewallException Id="RtspuFwException"
+                                Scope="any"
+                                Port="48010"
+                                Protocol="udp"
+                                Name="Moonlight - RTSPU"/>
+      </Component>
       <Component Id="Shortcuts" Guid="*">
         <Shortcut Id="StartMenuShortcut"
                   Name="Moonlight Internet Streaming Tester"
@@ -71,5 +129,14 @@
         <RegistryValue Root="HKCU" Key="Software\Moonlight Internet Streaming Tester" Name="Installed" Type="integer" Value="1" KeyPath="yes" />
       </Component>
     </ComponentGroup>
+
+    <InstallExecuteSequence>
+      <Custom Action="EnableMpsSvc" Before="StartMpsSvc">
+        <![CDATA[MPSSVC_START <> "#2"]]>
+      </Custom>
+      <Custom Action="StartMpsSvc" Before="StopServices">
+        <![CDATA[MPSSVC_START <> "#2"]]>
+      </Custom>
+    </InstallExecuteSequence>
   </Fragment>
 </Wix>

miss/miss.cpp

@@ -12,6 +12,7 @@
 #include <assert.h>
 #include <stdlib.h>
 
+#include "relay.h"
 #include "..\version.h"
 
 #pragma comment(lib, "miniupnpc.lib")
@@ -38,6 +39,7 @@ bool PCPMapPort(PSOCKADDR_STORAGE localAddr, int localAddrLen, PSOCKADDR_STORAGE
 #define POLLING_DELAY_SEC 120
 #define PORT_MAPPING_DURATION_SEC 3600
 #define UPNP_DISCOVERY_DELAY_MS 5000
+#define GAA_INITIAL_SIZE 8192
 
 static struct port_entry {
     int proto;
@@ -53,9 +55,9 @@ static struct port_entry {
     {IPPROTO_UDP, 48010}
 };
 
-static const int k_WolPorts[] = { 9 };
+static const int k_WolPorts[] = { 9, 47009 };
 
-bool UPnPMapPort(struct UPNPUrls* urls, struct IGDdatas* data, int proto, const char* myAddr, int port, bool enable, bool indefinite)
+bool UPnPMapPort(struct UPNPUrls* urls, struct IGDdatas* data, int proto, const char* myAddr, int port, bool enable, bool indefinite, bool validationPass)
 {
     char intClient[16];
     char intPort[6];
@@ -95,15 +97,40 @@ bool UPnPMapPort(struct UPNPUrls* urls, struct IGDdatas* data, int proto, const
     if (err == 714) {
         // NoSuchEntryInArray
         printf("NOT FOUND" NL);
+
+        if (validationPass) {
+            // On validation, we found a missing entry. Convert this entry to indefinite
+            // to see if it will stick.
+            indefinite = true;
+        }
+    }
+    else if (err == 606) {
+        printf("UNAUTHORIZED" NL);
+
+        // If we're just validating, we're done. We can't know if the entry was
+        // actually applied but we'll return true to avoid false errors if it was.
+        if (validationPass) {
+            return true;
+        }
     }
     else if (err == UPNPCOMMAND_SUCCESS) {
         // Some routers change the description, so we can't check that here
         if (!strcmp(intClient, myAddr)) {
             if (atoi(leaseDuration) == 0) {
-                printf("OK (Permanent)" NL);
+                printf("OK (Static, Internal port: %s)" NL, intPort);
+
+                // If we have an existing permanent mapping, we can just leave it alone.
+                if (enable) {
+                    return true;
+                }
             }
             else {
-                printf("OK (%s seconds remaining)" NL, leaseDuration);
+                printf("OK (%s seconds remaining, Internal port: %s)" NL, leaseDuration, intPort);
+            }
+
+            // If we're just validating, we found an entry, so we're done.
+            if (validationPass) {
+                return true;
             }
 
             if (!enable) {
@@ -123,6 +150,11 @@ bool UPnPMapPort(struct UPNPUrls* urls, struct IGDdatas* data, int proto, const
         else {
             printf("CONFLICT: %s %s" NL, intClient, desc);
 
+            // If we're just validating, we found an entry, so we're done.
+            if (validationPass) {
+                return true;
+            }
+
             // Some UPnP IGDs won't let unauthenticated clients delete other conflicting port mappings
             // for security reasons, but we will give it a try anyway. If GameStream is not enabled,
             // we will leave the conflicting entry alone to avoid disturbing another PC's port forwarding
@@ -146,6 +178,10 @@ bool UPnPMapPort(struct UPNPUrls* urls, struct IGDdatas* data, int proto, const
     }
     else {
         printf("ERROR %d (%s)" NL, err, strupnperror(err));
+
+        // If we get a strange error from the router, we'll assume it's some old broken IGDv1
+        // device and only use indefinite lease durations to hopefully avoid confusing it.
+        indefinite = true;
     }
 
     // Bail if GameStream is disabled
@@ -160,11 +196,31 @@ bool UPnPMapPort(struct UPNPUrls* urls, struct IGDdatas* data, int proto, const
     err = UPNP_AddPortMapping(
         urls->controlURL, data->first.servicetype, portStr,
         portStr, myAddr, myDesc, protoStr, nullptr, leaseDuration);
-    if (err == 725 && !indefinite) { // OnlyPermanentLeasesSupported
+    if (err != UPNPCOMMAND_SUCCESS && !indefinite) {
+        // This may be a broken IGD that doesn't like non-static mappings. Try a static
+        // mapping before finally giving up.
         err = UPNP_AddPortMapping(
             urls->controlURL, data->first.servicetype, portStr,
             portStr, myAddr, myDesc, protoStr, nullptr, "0");
-        printf("PERMANENT ");
+        printf("STATIC RETRY ");
+    }
+    else if (indefinite) {
+        printf("STATIC ");
+    }
+    if (err == 718 && proto == IPPROTO_UDP && port >= 47000) { // ConflictInMappingEntry
+        // Some UPnP implementations incorrectly deduplicate on the internal port instead
+        // of the external port, in violation of the UPnP IGD specification. Since GFE creates
+        // mappings on the same internal port as us, those routers break our mappings. To
+        // work around this issue, we run relays for each of the UDP ports on an alternate
+        // internal port. We'll try the alternate port if we get a conflict for a UDP entry.
+        // Given that these are already horribly non-spec compliant, we won't take any chances
+        // and we'll use an indefinite mapping too.
+        char altPortStr[6];
+        snprintf(altPortStr, sizeof(altPortStr), "%d", port + RELAY_PORT_OFFSET);
+        err = UPNP_AddPortMapping(
+            urls->controlURL, data->first.servicetype, portStr,
+            altPortStr, myAddr, myDesc, protoStr, nullptr, "0");
+        printf("ALTERNATE ");
     }
     if (err == UPNPCOMMAND_SUCCESS) {
         printf("OK" NL);
@@ -178,10 +234,7 @@ bool UPnPMapPort(struct UPNPUrls* urls, struct IGDdatas* data, int proto, const
 
 bool GetIP4OnLinkPrefixLength(char* lanAddressString, int* prefixLength)
 {
-    union {
-        IP_ADAPTER_ADDRESSES addresses;
-        char buffer[8192];
-    };
+    PIP_ADAPTER_ADDRESSES addresses;
     ULONG error;
     ULONG length;
     PIP_ADAPTER_ADDRESSES currentAdapter;
@@ -190,22 +243,34 @@ bool GetIP4OnLinkPrefixLength(char* lanAddressString, int* prefixLength)
 
     inet_pton(AF_INET, lanAddressString, &targetAddress);
 
-    // Get a list of all interfaces with IPv4 addresses on the system
-    length = sizeof(buffer);
-    error = GetAdaptersAddresses(AF_INET,
-        GAA_FLAG_SKIP_ANYCAST |
-        GAA_FLAG_SKIP_MULTICAST |
-        GAA_FLAG_SKIP_DNS_SERVER |
-        GAA_FLAG_SKIP_FRIENDLY_NAME,
-        NULL,
-        &addresses,
-        &length);
+    addresses = NULL;
+    length = GAA_INITIAL_SIZE;
+    do {
+        free(addresses);
+        addresses = (PIP_ADAPTER_ADDRESSES)malloc(length);
+        if (addresses == NULL) {
+            printf("malloc(%u) failed" NL, length);
+            return false;
+        }
+
+        // Get a list of all interfaces with IPv4 addresses on the system
+        error = GetAdaptersAddresses(AF_INET,
+            GAA_FLAG_SKIP_ANYCAST |
+            GAA_FLAG_SKIP_MULTICAST |
+            GAA_FLAG_SKIP_DNS_SERVER |
+            GAA_FLAG_SKIP_FRIENDLY_NAME,
+            NULL,
+            addresses,
+            &length);
+    } while (error == ERROR_BUFFER_OVERFLOW);
+
     if (error != ERROR_SUCCESS) {
         printf("GetAdaptersAddresses() failed: %d" NL, error);
+        free(addresses);
         return false;
     }
 
-    currentAdapter = &addresses;
+    currentAdapter = addresses;
     currentAddress = nullptr;
     while (currentAdapter != nullptr) {
         currentAddress = currentAdapter->FirstUnicastAddress;
@@ -216,6 +281,7 @@ bool GetIP4OnLinkPrefixLength(char* lanAddressString, int* prefixLength)
 
             if (RtlEqualMemory(&currentAddrV4->sin_addr, &targetAddress, sizeof(targetAddress))) {
                 *prefixLength = currentAddress->OnLinkPrefixLength;
+                free(addresses);
                 return true;
             }
 
@@ -226,6 +292,7 @@ bool GetIP4OnLinkPrefixLength(char* lanAddressString, int* prefixLength)
     }
 
     printf("No adapter found with IPv4 address: %s" NL, lanAddressString);
+    free(addresses);
     return false;
 }
 
@@ -279,8 +346,9 @@ bool UPnPHandleDeviceList(struct UPNPDev* list, bool enable, char* lanAddrOverri
         portMappingInternalAddress = localAddress;
     }
 
+    // Create the port mappings
     for (int i = 0; i < ARRAYSIZE(k_Ports); i++) {
-        if (!UPnPMapPort(&urls, &data, k_Ports[i].proto, portMappingInternalAddress, k_Ports[i].port, enable, false)) {
+        if (!UPnPMapPort(&urls, &data, k_Ports[i].proto, portMappingInternalAddress, k_Ports[i].port, enable, false, false)) {
             success = false;
         }
     }
@@ -304,13 +372,28 @@ bool UPnPHandleDeviceList(struct UPNPDev* list, bool enable, char* lanAddrOverri
                 char broadcastAddrStr[128];
                 inet_ntop(AF_INET, &broadcastAddr, broadcastAddrStr, sizeof(broadcastAddrStr));
 
-                UPnPMapPort(&urls, &data, IPPROTO_UDP, broadcastAddrStr, k_WolPorts[i], enable, true);
+                UPnPMapPort(&urls, &data, IPPROTO_UDP, broadcastAddrStr, k_WolPorts[i], enable, true, false);
             }
         }
         else {
             // When we're mapping the WOL ports upstream of our router, we map directly to
             // the port on the upstream address (likely our router's WAN interface).
-            UPnPMapPort(&urls, &data, IPPROTO_UDP, lanAddrOverride, k_WolPorts[i], enable, true);
+            UPnPMapPort(&urls, &data, IPPROTO_UDP, lanAddrOverride, k_WolPorts[i], enable, true, false);
+        }
+    }
+
+    // Validate the rules are present and correct if they claimed to be added successfully
+    if (success && enable) {
+        // Wait 10 seconds for the router state to quiesce
+        printf("Waiting before UPnP port validation...");
+        Sleep(10000);
+        printf("done" NL);
+
+        // Perform the validation pass (converting any now missing entries to permanent ones)
+        for (int i = 0; i < ARRAYSIZE(k_Ports); i++) {
+            if (!UPnPMapPort(&urls, &data, k_Ports[i].proto, portMappingInternalAddress, k_Ports[i].port, enable, false, true)) {
+                success = false;
+            }
         }
     }
 
@@ -344,7 +427,7 @@ bool NATPMPMapPort(natpmp_t* natpmp, int proto, int port, bool enable, bool inde
         lifetime = 604800; // 1 week
     }
     else {
-        lifetime = 3600;
+        lifetime = PORT_MAPPING_DURATION_SEC;
     }
 
     printf("Updating NAT-PMP port mapping for %s %d...", proto == IPPROTO_TCP ? "TCP" : "UDP", port);
@@ -386,15 +469,6 @@ bool NATPMPMapPort(natpmp_t* natpmp, int proto, int port, bool enable, bool inde
     else if (response.pnu.newportmapping.mappedpublicport != port) {
         printf("CONFLICT" NL);
 
-        // Some buggy routers (Untangle) will change the *internal* port when
-        // adjusting a port mapping request that collides. This is why we also
-        // pass privateport back from the response and not from the port we originally
-        // asked for. Warn in this case.
-        if (response.pnu.newportmapping.privateport != port) {
-            printf("Buggy router changed the internal port when handling NAT-PMP conflict! (%d -> %d)" NL,
-                port, response.pnu.newportmapping.privateport);
-        }
-
         // It couldn't assign us the external port we requested and gave us an alternate external port.
         // We can't use this alternate mapping, so immediately release it.
         printf("Deleting unwanted NAT-PMP mapping for %s %d...", proto == IPPROTO_TCP ? "TCP" : "UDP", response.pnu.newportmapping.mappedpublicport);
@@ -743,25 +817,28 @@ void NETIOAPI_API_ IpInterfaceChangeNotificationCallback(PVOID context, PMIB_IPI
     SetEvent((HANDLE)context);
 }
 
-void ResetLogFile()
+void ResetLogFile(bool standaloneExe)
 {
-    char oldLogFilePath[MAX_PATH + 1];
-    char currentLogFilePath[MAX_PATH + 1];
     char timeString[MAX_PATH + 1] = {};
     SYSTEMTIME time;
 
-    ExpandEnvironmentStringsA("%ProgramData%\\MISS\\miss-old.log", oldLogFilePath, sizeof(oldLogFilePath));
-    ExpandEnvironmentStringsA("%ProgramData%\\MISS\\miss-current.log", currentLogFilePath, sizeof(currentLogFilePath));
+    if (!standaloneExe) {
+        char oldLogFilePath[MAX_PATH + 1];
+        char currentLogFilePath[MAX_PATH + 1];
 
-    // Close the existing stdout handle. This is important because otherwise
-    // it may still be open as stdout when we try to MoveFileEx below.
-    fclose(stdout);
+        ExpandEnvironmentStringsA("%ProgramData%\\MISS\\miss-old.log", oldLogFilePath, sizeof(oldLogFilePath));
+        ExpandEnvironmentStringsA("%ProgramData%\\MISS\\miss-current.log", currentLogFilePath, sizeof(currentLogFilePath));
 
-    // Rotate the current to the old log file
-    MoveFileExA(currentLogFilePath, oldLogFilePath, MOVEFILE_REPLACE_EXISTING);
+        // Close the existing stdout handle. This is important because otherwise
+        // it may still be open as stdout when we try to MoveFileEx below.
+        fclose(stdout);
 
-    // Redirect stdout to this new file
-    freopen(currentLogFilePath, "w", stdout);
+        // Rotate the current to the old log file
+        MoveFileExA(currentLogFilePath, oldLogFilePath, MOVEFILE_REPLACE_EXISTING);
+
+        // Redirect stdout to this new file
+        freopen(currentLogFilePath, "w", stdout);
+    }
 
     // Print a log header
     printf("Moonlight Internet Streaming Service v" VER_VERSION_STR NL);
@@ -798,13 +875,24 @@ DWORD WINAPI GameStreamStateChangeThread(PVOID Context)
     return err;
 }
 
-int Run()
+int Run(bool standaloneExe)
 {
     HANDLE ifaceChangeEvent = CreateEvent(nullptr, true, false, nullptr);
     HANDLE gsChangeEvent = CreateEvent(nullptr, true, false, nullptr);
     HANDLE events[2] = { ifaceChangeEvent, gsChangeEvent };
 
-    ResetLogFile();
+    ResetLogFile(standaloneExe);
+
+    // Bump the process priority class to above normal. The UDP relay threads will
+    // further raise their own thread priorities to avoid preemption by other activity.
+    SetPriorityClass(GetCurrentProcess(), ABOVE_NORMAL_PRIORITY_CLASS);
+
+    // Create the UDP alternate port relays
+    for (int i = 0; i < ARRAYSIZE(k_Ports); i++) {
+        if (k_Ports[i].proto == IPPROTO_UDP) {
+            StartUdpRelay(k_Ports[i].port);
+        }
+    }
 
     // Create the thread to watch for GameStream state changes
     CreateThread(nullptr, 0, GameStreamStateChangeThread, gsChangeEvent, 0, nullptr);
@@ -826,7 +914,7 @@ int Run()
         ULONGLONG beforeSleepTime = GetTickCount64();
         DWORD ret = WaitForMultipleObjects(ARRAYSIZE(events), events, false, POLLING_DELAY_SEC * 1000);
         if (ret == WAIT_OBJECT_0) {
-            ResetLogFile();
+            ResetLogFile(standaloneExe);
 
             printf("Woke up for interface change notification after %lld seconds" NL,
                 (GetTickCount64() - beforeSleepTime) / 1000);
@@ -835,13 +923,13 @@ int Run()
             Sleep(10000);
         }
         else if (ret == WAIT_OBJECT_0 + 1) {
-            ResetLogFile();
+            ResetLogFile(standaloneExe);
 
             printf("Woke up for GameStream state change notification after %lld seconds" NL,
                 (GetTickCount64() - beforeSleepTime) / 1000);
         }
         else {
-            ResetLogFile();
+            ResetLogFile(standaloneExe);
 
             printf("Woke up for periodic refresh" NL);
         }
@@ -902,7 +990,7 @@ ServiceMain(DWORD dwArgc, LPTSTR *lpszArgv)
     SetServiceStatus(ServiceStatusHandle, &ServiceStatus);
 
     // Start the service
-    err = Run();
+    err = Run(false);
     if (err != 0) {
         ServiceStatus.dwCurrentState = SERVICE_STOPPED;
         ServiceStatus.dwWin32ExitCode = err;
@@ -925,7 +1013,7 @@ int main(int argc, char* argv[])
     }
 
     if (argc == 2 && !strcmp(argv[1], "exe")) {
-        Run();
+        Run(true);
         return 0;
     }
 

miss/miss.vcxproj

@@ -163,6 +163,7 @@
   <ItemGroup>
     <ClCompile Include="miss.cpp" />
     <ClCompile Include="pcp.cpp" />
+    <ClCompile Include="relay.cpp" />
     <ClCompile Include="tracer.cpp" />
   </ItemGroup>
   <ItemGroup>
@@ -170,6 +171,7 @@
   </ItemGroup>
   <ItemGroup>
     <ClInclude Include="..\version.h" />
+    <ClInclude Include="relay.h" />
   </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">

miss/miss.vcxproj.filters

@@ -24,6 +24,9 @@
     <ClCompile Include="pcp.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="relay.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <ResourceCompile Include="miss.rc">
@@ -34,5 +37,8 @@
     <ClInclude Include="..\version.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="relay.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
   </ItemGroup>
 </Project>

miss/relay.cpp

@@ -0,0 +1,110 @@
+#define WIN32_LEAN_AND_MEAN
+#include <Windows.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <WinSock2.h>
+#include <Ws2ipdef.h>
+
+#include "relay.h"
+
+typedef struct _UDP_TUPLE {
+    SOCKET socket;
+    unsigned short port;
+} UDP_TUPLE, *PUDP_TUPLE;
+
+DWORD
+WINAPI
+UdpRelayThreadProc(LPVOID Context)
+{
+    PUDP_TUPLE tuple = (PUDP_TUPLE)Context;
+    USHORT nboPort = htons(tuple->port);
+    SOCKADDR_IN lastRemoteAddr;
+
+    // Ensure the relay threads aren't preempted by games or other CPU intensive activity
+    SetThreadPriority(GetCurrentThread(), THREAD_PRIORITY_HIGHEST);
+
+    RtlZeroMemory(&lastRemoteAddr, sizeof(lastRemoteAddr));
+
+    for (;;) {
+        char buffer[4096];
+        SOCKADDR_IN sourceAddr;
+        int sourceAddrLen;
+        int recvLen;
+
+        sourceAddrLen = sizeof(sourceAddr);
+        recvLen = recvfrom(tuple->socket, buffer, sizeof(buffer), 0, (PSOCKADDR)&sourceAddr, &sourceAddrLen);
+        if (recvLen == SOCKET_ERROR) {
+            continue;
+        }
+        
+        SOCKADDR_IN destinationAddr;
+        if (RtlEqualMemory(&sourceAddr.sin_addr, &in4addr_loopback, sizeof(sourceAddr.sin_addr)) && sourceAddr.sin_port == nboPort) {
+            // Traffic incoming from loopback interface - send it to the last remote address
+            destinationAddr = lastRemoteAddr;
+        }
+        else {
+            // Traffic incoming from the remote host - remember the source
+            lastRemoteAddr = sourceAddr;
+
+            // Send it to the normal port via the loopback adapter
+            destinationAddr = sourceAddr;
+            destinationAddr.sin_addr = in4addr_loopback;
+            destinationAddr.sin_port = nboPort;
+        }
+
+        sendto(tuple->socket, buffer, recvLen, 0, (PSOCKADDR)&destinationAddr, sizeof(destinationAddr));
+    }
+
+    closesocket(tuple->socket);
+    free(tuple);
+    return 0;
+}
+
+int StartUdpRelay(unsigned short Port)
+{
+    SOCKET sock;
+    SOCKADDR_IN addr;
+    HANDLE thread;
+    PUDP_TUPLE tuple;
+    int error;
+
+    sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+    if (sock == INVALID_SOCKET) {
+        error = WSAGetLastError();
+        printf("socket() failed: %d\n", error);
+        return error;
+    }
+
+    // Bind to the alternate port
+    RtlZeroMemory(&addr, sizeof(addr));
+    addr.sin_family = AF_INET;
+    addr.sin_port = htons(Port + RELAY_PORT_OFFSET);
+    if (bind(sock, (PSOCKADDR)&addr, sizeof(addr)) == SOCKET_ERROR) {
+        error = WSAGetLastError();
+        printf("bind() failed: %d\n", error);
+        closesocket(sock);
+        return error;
+    }
+
+    tuple = (PUDP_TUPLE)malloc(sizeof(*tuple));
+    if (tuple == NULL) {
+        return ERROR_OUTOFMEMORY;
+    }
+
+    tuple->socket = sock;
+    tuple->port = Port;
+
+    thread = CreateThread(NULL, 0, UdpRelayThreadProc, tuple, 0, NULL);
+    if (thread == NULL) {
+        error = GetLastError();
+        printf("CreateThread() failed: %d\n", error);
+        closesocket(sock);
+        return error;
+    }
+
+    CloseHandle(thread);
+
+    return 0;
+}

miss/relay.h

@@ -0,0 +1,5 @@
+#pragma once
+
+#define RELAY_PORT_OFFSET -10000
+
+int StartUdpRelay(unsigned short Port);

mist/mist.cpp

@@ -5,13 +5,19 @@
 #include <assert.h>
 #include <shellapi.h>
 #include <objbase.h>
-#include <WinInet.h>
+#include <WinHttp.h>
+#include <wtsapi32.h>
+#include <powerbase.h>
+#include <VersionHelpers.h>
+#include <tlhelp32.h>
 
 #pragma comment(lib, "miniupnpc.lib")
 #pragma comment(lib, "libnatpmp.lib")
 #pragma comment(lib, "ws2_32.lib")
 #pragma comment(lib, "iphlpapi.lib")
-#pragma comment(lib, "wininet.lib")
+#pragma comment(lib, "winhttp.lib")
+#pragma comment(lib, "wtsapi32.lib")
+#pragma comment(lib, "powrprof.lib")
 
 #define MINIUPNP_STATICLIB
 #include <miniupnpc/miniupnpc.h>
@@ -21,6 +27,10 @@
 #define NATPMP_STATICLIB
 #include <natpmp.h>
 
+#define LOOPBACK_SERVER_PORT_OFFSET -10000
+
+#define GAA_INITIAL_SIZE 8192
+
 static struct port_entry {
     int proto;
     int port;
@@ -178,6 +188,56 @@ void DisplayMessage(const char* message, const char* helpUrl = nullptr, MessageP
     }
 }
 
+bool ExecuteCommand(PCSTR command, PCHAR outputBuffer, DWORD outputBufferLength)
+{
+    SECURITY_ATTRIBUTES attribs;
+    STARTUPINFO si;
+    PROCESS_INFORMATION pi;
+    HANDLE outReadHandle;
+    DWORD bytesRead = 0;
+
+    ZeroMemory(&si, sizeof(si));
+    si.cb = sizeof(si);
+    si.dwFlags = STARTF_USESHOWWINDOW | STARTF_USESTDHANDLES;
+    si.wShowWindow = SW_HIDE;
+
+    ZeroMemory(&attribs, sizeof(attribs));
+    attribs.nLength = sizeof(attribs);
+    attribs.bInheritHandle = TRUE;
+
+    if (!CreatePipe(&outReadHandle, &si.hStdOutput, &attribs, 0))
+    {
+        fprintf(LOG_OUT, "CreatePipe() failed: %d\n", GetLastError());
+        return false;
+    }
+
+    si.hStdError = si.hStdOutput;
+
+    if (!CreateProcess(NULL, (LPSTR)command, NULL, NULL, TRUE, 0, NULL, NULL, &si, &pi))
+    {
+        fprintf(LOG_OUT, "CreateProcess() failed: %d\n", GetLastError());
+        CloseHandle(si.hStdOutput);
+        return false;
+    }
+
+    WaitForSingleObject(pi.hProcess, INFINITE);
+
+    CloseHandle(si.hStdOutput);
+    CloseHandle(pi.hProcess);
+    CloseHandle(pi.hThread);
+
+    if (!ReadFile(outReadHandle, outputBuffer, outputBufferLength, &bytesRead, NULL))
+    {
+        fprintf(LOG_OUT, "ReadFile() failed: %d\n", GetLastError());
+        CloseHandle(outReadHandle);
+        return false;
+    }
+
+    outputBuffer[bytesRead] = 0;
+    CloseHandle(outReadHandle);
+    return true;
+}
+
 bool IsGameStreamEnabled()
 {
     DWORD error;
@@ -211,6 +271,123 @@ bool IsGameStreamEnabled()
     }
 }
 
+bool IsCurrentlyStreaming()
+{
+    bool ret = false;
+    HANDLE processSnapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
+
+    PROCESSENTRY32 procEntry;
+    procEntry.dwSize = sizeof(procEntry);
+    Process32First(processSnapshot, &procEntry);
+
+    do {
+        // If we find nvstreamer.exe running, we're currently streaming
+        if (_stricmp(procEntry.szExeFile, "nvstreamer.exe") == 0) {
+            ret = true;
+            break;
+        }
+    } while (Process32Next(processSnapshot, &procEntry));
+
+    CloseHandle(processSnapshot);
+
+    return ret;
+}
+
+bool IsConsoleSessionActive()
+{
+    PWTS_SESSION_INFO_1 sessionInfo;
+    DWORD sessionCount;
+    DWORD level;
+    bool ret;
+    DWORD activeSessionId = WTSGetActiveConsoleSessionId();
+
+    if (activeSessionId == 0xFFFFFFFF) {
+        fprintf(LOG_OUT, "No active console session detected\n");
+        return false;
+    }
+
+    level = 1;
+    if (!WTSEnumerateSessionsEx(WTS_CURRENT_SERVER_HANDLE, &level, 0, &sessionInfo, &sessionCount)) {
+        fprintf(LOG_OUT, "WTSEnumerateSessionsEx() failed: %d\n", GetLastError());
+        return false;
+    }
+
+    ret = false;
+    for (int i = 0; i < sessionCount; i++)
+    {
+        if (sessionInfo[i].SessionId == activeSessionId) {
+            if (sessionInfo[i].pUserName != nullptr) {
+                fprintf(LOG_OUT, "Session %d has active user\n", sessionInfo[i].SessionId);
+                ret = true;
+                break;
+            }
+        }
+    }
+
+    WTSFreeMemoryExW(WTSTypeSessionInfoLevel1, sessionInfo, sessionCount);
+    return ret;
+}
+
+bool IsSleepEnabled()
+{
+    SYSTEM_POWER_POLICY powerPolicy;
+
+    if (CallNtPowerInformation(SystemPowerPolicyAc, NULL, 0, &powerPolicy, sizeof(powerPolicy)) < 0) {
+        return false;
+    }
+
+    return powerPolicy.IdleTimeout != 0 && powerPolicy.Idle.Action == PowerActionSleep;
+}
+
+bool IsHibernationEnabled()
+{
+    SYSTEM_POWER_POLICY powerPolicy;
+
+    if (CallNtPowerInformation(SystemPowerPolicyAc, NULL, 0, &powerPolicy, sizeof(powerPolicy)) < 0) {
+        return false;
+    }
+
+    return powerPolicy.DozeS4Timeout != 0 || (powerPolicy.IdleTimeout != 0 && powerPolicy.Idle.Action == PowerActionHibernate);
+}
+
+bool IsLocalNetworkAccessBlocked()
+{
+    MIB_IPFORWARDROW route;
+    DWORD error;
+    SOCKADDR_IN sin;
+    SOCKET s;
+    
+    error = GetBestRoute(0, 0, &route);
+    if (error != NO_ERROR) {
+        fprintf(LOG_OUT, "GetBestRoute() failed: %d\n", error);
+        return false;
+    }
+
+    s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+    if (s == INVALID_SOCKET) {
+        fprintf(LOG_OUT, "socket() failed: %d\n", error);
+        return false;
+    }
+
+    RtlZeroMemory(&sin, sizeof(sin));
+    sin.sin_family = AF_INET;
+    sin.sin_addr.S_un.S_addr = route.dwForwardNextHop;
+    sin.sin_port = htons(80);
+
+    if (connect(s, (PSOCKADDR)&sin, sizeof(sin)) == 0) {
+        error = NO_ERROR;
+        fprintf(LOG_OUT, "connect(%s, %d) successful\n", inet_ntoa(sin.sin_addr), ntohs(sin.sin_port));
+    }
+    else {
+        error = WSAGetLastError();
+        fprintf(LOG_OUT, "connect(%s, %d) failed: %d\n", inet_ntoa(sin.sin_addr), ntohs(sin.sin_port), error);
+    }
+
+    closesocket(s);
+
+    return error == WSAEACCES;
+}
+
 bool IsZeroTierInstalled()
 {
     DWORD error;
@@ -307,7 +484,7 @@ PortTestStatus TestPort(PSOCKADDR_STORAGE addr, int proto, int port, bool withSe
         sizeof(SOCKADDR_IN) : sizeof(SOCKADDR_IN6);
 
     RtlCopyMemory(&sin6, addr, addrLen);
-    sin6.sin6_port = htons(port);
+    sin6.sin6_port = htons(port + (isLoopbackRelay ? LOOPBACK_SERVER_PORT_OFFSET : 0));
 
     if (proto == IPPROTO_TCP) {
         err = connect(clientSock, (struct sockaddr*)&sin6, addrLen);
@@ -397,64 +574,100 @@ PortTestStatus TestPort(PSOCKADDR_STORAGE addr, int proto, int port, bool withSe
     }
 }
 
-PortTestStatus TestHttpPort(PSOCKADDR_STORAGE addr, int port)
+PortTestStatus TestHttpPort(PSOCKADDR_STORAGE addr, int port, bool isLoopbackRelay)
 {
-    HINTERNET hInternet;
-    HINTERNET hRequest;
-    char url[1024];
+    HINTERNET hSession = nullptr;
+    HINTERNET hConnection = nullptr;
+    HINTERNET hRequest = nullptr;
+    PortTestStatus result;
 
-    hInternet = InternetOpenA("MIST", 0, nullptr, nullptr, 0);
-    if (hInternet == nullptr) {
-        fprintf(LOG_OUT, "InternetOpen() failed: %d\n", GetLastError());
-        return PortTestError;
+    hSession = WinHttpOpen(L"MIST", WINHTTP_ACCESS_TYPE_NO_PROXY, WINHTTP_NO_PROXY_NAME, WINHTTP_NO_PROXY_BYPASS, 0);
+    if (hSession == nullptr) {
+        fprintf(LOG_OUT, "WinHttpOpen() failed: %d\n", GetLastError());
+        result = PortTestError;
+        goto Exit;
     }
 
-    char addrStr[INET6_ADDRSTRLEN + 2];
+    // WinHTTP's default timeouts are very long. Set them to something more reasonable.
+    if (!WinHttpSetTimeouts(hSession, 0, 3000, 5000, 5000)) {
+        fprintf(LOG_OUT, "WinHttpSetTimeouts() failed: %d\n", GetLastError());
+    }
+
+    // Windows 8.1 enabled TLSv1.2 for WinHTTP by default (8.0 enables it for Schannel but not WinHTTP)
+    // https://docs.microsoft.com/en-us/security/engineering/solving-tls1-problem
+    if (!IsWindows8Point1OrGreater()) {
+        DWORD protocols = WINHTTP_FLAG_SECURE_PROTOCOL_TLS1 |
+                          WINHTTP_FLAG_SECURE_PROTOCOL_TLS1_1 |
+                          WINHTTP_FLAG_SECURE_PROTOCOL_TLS1_2;
+
+        if (!WinHttpSetOption(hSession, WINHTTP_OPTION_SECURE_PROTOCOLS, &protocols, sizeof(protocols))) {
+            fprintf(LOG_OUT, "WinHttpSetOption(WINHTTP_OPTION_SECURE_PROTOCOLS) failed: %d\n", GetLastError());
+        }
+    }
+
+    WCHAR urlEscapedAddr[INET6_ADDRSTRLEN + 2];
     if (addr->ss_family == AF_INET) {
-        inet_ntop(AF_INET, &((struct sockaddr_in*)addr)->sin_addr, addrStr, sizeof(addrStr));
+        InetNtopW(AF_INET, &((struct sockaddr_in*)addr)->sin_addr, urlEscapedAddr, ARRAYSIZE(urlEscapedAddr));
     }
     else {
         // The address string must be escaped for usage in URLs
-        addrStr[0] = '[';
-        inet_ntop(AF_INET6, &((struct sockaddr_in6*)addr)->sin6_addr, &addrStr[1], INET6_ADDRSTRLEN);
-        strcat_s(addrStr, "]");
+        urlEscapedAddr[0] = L'[';
+        InetNtopW(AF_INET6, &((struct sockaddr_in6*)addr)->sin6_addr, &urlEscapedAddr[1], INET6_ADDRSTRLEN);
+        wcscat_s(urlEscapedAddr, L"]");
     }
 
-    sprintf(url, "%s://%s:%d/",
-        port == 47989 ? "http" : "https",
-        addrStr,
-        port);
+    hConnection = WinHttpConnect(hSession, urlEscapedAddr, port + (isLoopbackRelay ? LOOPBACK_SERVER_PORT_OFFSET : 0), NULL);
+    if (hConnection == nullptr) {
+        fprintf(LOG_OUT, "WinHttpConnect() failed: %d\n", GetLastError());
+        result = PortTestError;
+        goto Exit;
+    }
 
-    hRequest = InternetOpenUrlA(hInternet, url, nullptr, 0,
-        INTERNET_FLAG_IGNORE_CERT_DATE_INVALID | INTERNET_FLAG_NO_UI | INTERNET_FLAG_NO_AUTH | INTERNET_FLAG_NO_COOKIES | INTERNET_FLAG_RELOAD,
-        NULL);
-    if (hRequest == nullptr) {
-        if (GetLastError() == ERROR_INTERNET_CLIENT_AUTH_CERT_NEEDED) {
+    hRequest = WinHttpOpenRequest(hConnection, L"GET", L"/", NULL, WINHTTP_NO_REFERER, WINHTTP_DEFAULT_ACCEPT_TYPES,
+                                  port == 47984 ? WINHTTP_FLAG_SECURE : 0);
+    if (hConnection == nullptr) {
+        fprintf(LOG_OUT, "WinHttpOpenRequest() failed: %d\n", GetLastError());
+        result = PortTestError;
+        goto Exit;
+    }
+
+    if (!WinHttpSendRequest(hRequest, WINHTTP_NO_ADDITIONAL_HEADERS, 0, WINHTTP_NO_REQUEST_DATA, 0, 0, 0) || !WinHttpReceiveResponse(hRequest, NULL)) {
+        if (GetLastError() == ERROR_WINHTTP_CLIENT_AUTH_CERT_NEEDED) {
             // This is expected for our HTTPS connection
             fprintf(LOG_OUT, "Success\n");
+            result = PortTestOk;
         }
         else {
             // CANNOT_CONNECT is the "expected" error
-            if (GetLastError() == ERROR_INTERNET_CANNOT_CONNECT) {
+            if (GetLastError() == ERROR_WINHTTP_CANNOT_CONNECT) {
                 fprintf(LOG_OUT, "Failed\n");
             }
             else {
                 fprintf(LOG_OUT, "Failed: %d\n", GetLastError());
             }
 
-            InternetCloseHandle(hInternet);
-            return PortTestError;
+            result = PortTestError;
         }
+
+        goto Exit;
     }
     else {
         fprintf(LOG_OUT, "Success\n");
-        InternetCloseHandle(hRequest);
+        result = PortTestOk;
     }
 
+Exit:
+    if (hRequest != nullptr) {
+        WinHttpCloseHandle(hRequest);
+    }
+    if (hConnection != nullptr) {
+        WinHttpCloseHandle(hConnection);
+    }
+    if (hSession != nullptr) {
+        WinHttpCloseHandle(hSession);
+    }
 
-    InternetCloseHandle(hInternet);
-
-    return PortTestOk;
+    return result;
 }
 
 bool TestAllPorts(PSOCKADDR_STORAGE addr, char* portMsg, int portMsgLen, bool isLoopbackRelay, bool consolePrint, bool* allPortsFailed = nullptr)
@@ -466,9 +679,7 @@ bool TestAllPorts(PSOCKADDR_STORAGE addr, char* portMsg, int portMsgLen, bool is
     }
 
     for (int i = 0; i < ARRAYSIZE(k_Ports); i++) {
-        fprintf(LOG_OUT, "Testing %s %d...",
-            k_Ports[i].proto == IPPROTO_TCP ? "TCP" : "UDP",
-            k_Ports[i].port);
+        PortTestStatus status;
 
         if (consolePrint) {
             fprintf(CONSOLE_OUT, "\tTesting %s %d...\n",
@@ -476,15 +687,18 @@ bool TestAllPorts(PSOCKADDR_STORAGE addr, char* portMsg, int portMsgLen, bool is
                 k_Ports[i].port);
         }
 
-        PortTestStatus status = TestPort(addr, k_Ports[i].proto, k_Ports[i].port, k_Ports[i].withServer, isLoopbackRelay);
-
-        if (status != PortTestError && !k_Ports[i].withServer) {
+        if (!k_Ports[i].withServer) {
             // Test using a real HTTP client if the port wasn't totally dead.
             // This is required to confirm functionality with the loopback relay.
-            // TestHttpPort() can take significantly longer to timeout than TestPort(),
-            // so we only do this test if we believe we're likely to get a response.
+            assert(k_Ports[i].proto == IPPROTO_TCP);
             fprintf(LOG_OUT, "Testing TCP %d with HTTP traffic...", k_Ports[i].port);
-            status = TestHttpPort(addr, k_Ports[i].port);
+            status = TestHttpPort(addr, k_Ports[i].port, isLoopbackRelay);
+        }
+        else {
+            fprintf(LOG_OUT, "Testing %s %d...",
+                k_Ports[i].proto == IPPROTO_TCP ? "TCP" : "UDP",
+                k_Ports[i].port);
+            status = TestPort(addr, k_Ports[i].proto, k_Ports[i].port, k_Ports[i].withServer, isLoopbackRelay);
         }
 
         if (status != PortTestOk) {
@@ -511,6 +725,81 @@ bool TestAllPorts(PSOCKADDR_STORAGE addr, char* portMsg, int portMsgLen, bool is
     return ret;
 }
 
+bool IsTestServerReachable(struct addrinfo* addrinfo, unsigned short port)
+{
+    SOCKET s;
+    FD_SET writeFds, exceptFds;
+    int err;
+    struct timeval tv = {};
+    SOCKADDR_STORAGE addr;
+    char testServerStr[INET6_ADDRSTRLEN];
+
+    memcpy(&addr, addrinfo->ai_addr, addrinfo->ai_addrlen);
+    ((PSOCKADDR_IN6)&addr)->sin6_port = htons(port);
+
+    if (addr.ss_family == AF_INET) {
+        inet_ntop(AF_INET, &((struct sockaddr_in*)&addr)->sin_addr, testServerStr, sizeof(testServerStr));
+    }
+    else {
+        inet_ntop(AF_INET6, &((struct sockaddr_in6*)&addr)->sin6_addr, testServerStr, sizeof(testServerStr));
+    }
+
+    fprintf(LOG_OUT, "Testing reachability of relay server %s...", testServerStr);
+
+    s = socket(addrinfo->ai_family, SOCK_STREAM, IPPROTO_TCP);
+    if (s == INVALID_SOCKET) {
+        fprintf(LOG_OUT, "socket() failed: %d\n", WSAGetLastError());
+        return false;
+    }
+
+    ULONG nbIo = 1;
+    err = ioctlsocket(s, FIONBIO, &nbIo);
+    if (err == SOCKET_ERROR) {
+        fprintf(LOG_OUT, "ioctlsocket() failed: %d\n", WSAGetLastError());
+        closesocket(s);
+        return false;
+    }
+
+    err = connect(s, (PSOCKADDR)&addr, addrinfo->ai_addrlen);
+    if (err == SOCKET_ERROR && WSAGetLastError() != WSAEWOULDBLOCK) {
+        fprintf(LOG_OUT, "Unreachable (%d)\n", WSAGetLastError());
+        closesocket(s);
+        return false;
+    }
+
+    FD_ZERO(&writeFds);
+    FD_ZERO(&exceptFds);
+
+    FD_SET(s, &writeFds);
+    FD_SET(s, &exceptFds);
+
+    tv.tv_sec = 3;
+    err = select(0, nullptr, &writeFds, &exceptFds, &tv);
+    if (err == SOCKET_ERROR) {
+        fprintf(LOG_OUT, "select() failed: %d\n", WSAGetLastError());
+        closesocket(s);
+        return false;
+    }
+    else if (err == 0) {
+        fprintf(LOG_OUT, "Unreachable (timeout)\n");
+        closesocket(s);
+        return false;
+    }
+    else {
+        int optlen = sizeof(err);
+        getsockopt(s, SOL_SOCKET, SO_ERROR, (char*)&err, &optlen);
+        closesocket(s);
+
+        if (err != 0 || FD_ISSET(s, &exceptFds)) {
+            fprintf(LOG_OUT, "Unreachable (%d)\n", err);
+            return false;
+        }
+
+        fprintf(LOG_OUT, "Reachable\n");
+        return true;
+    }
+}
+
 bool FindLocalInterfaceIPAddress(int family, PSOCKADDR_STORAGE addr)
 {
     SOCKET s;
@@ -524,9 +813,16 @@ bool FindLocalInterfaceIPAddress(int family, PSOCKADDR_STORAGE addr)
     hint.ai_socktype = SOCK_STREAM;
     hint.ai_protocol = IPPROTO_TCP;
     hint.ai_flags = AI_ADDRCONFIG;
-    err = getaddrinfo("moonlight-stream.org", "https", &hint, &result);
+    err = getaddrinfo("moonlight-stream.org", "443", &hint, &result);
     if (err != 0 || result == NULL) {
-        fprintf(LOG_OUT, "getaddrinfo() failed: %d\n", err);
+        // AI_ADDRCONFIG will mask unusable addresses, so we may get nothing
+        // We get WSANO_DATA or WSAHOST_NOT_FOUND depending on whether it's V4 or V6 :(
+        if (err == WSANO_DATA || err == WSAHOST_NOT_FOUND) {
+            fprintf(LOG_OUT, "NONE\n");
+        }
+        else {
+            fprintf(LOG_OUT, "getaddrinfo() failed: %d\n", err);
+        }
         return false;
     }
 
@@ -570,31 +866,40 @@ bool FindLocalInterfaceIPAddress(int family, PSOCKADDR_STORAGE addr)
 
 bool FindZeroTierInterfaceAddress(PSOCKADDR_STORAGE addr)
 {
-    union {
-        IP_ADAPTER_ADDRESSES addresses;
-        char buffer[8192];
-    };
+    PIP_ADAPTER_ADDRESSES addresses;
     ULONG error;
     ULONG length;
     PIP_ADAPTER_ADDRESSES currentAdapter;
     PIP_ADAPTER_UNICAST_ADDRESS currentAddress;
 
-    // Get all IPv4 interfaces
-    length = sizeof(buffer);
-    error = GetAdaptersAddresses(AF_INET,
-        GAA_FLAG_SKIP_ANYCAST |
-        GAA_FLAG_SKIP_MULTICAST |
-        GAA_FLAG_SKIP_DNS_SERVER |
-        GAA_FLAG_SKIP_FRIENDLY_NAME,
-        NULL,
-        &addresses,
-        &length);
+    addresses = NULL;
+    length = GAA_INITIAL_SIZE;
+    do {
+        free(addresses);
+        addresses = (PIP_ADAPTER_ADDRESSES)malloc(length);
+        if (addresses == NULL) {
+            fprintf(LOG_OUT, "malloc(%u) failed\n", length);
+            return false;
+        }
+
+        // Get all IPv4 interfaces
+        error = GetAdaptersAddresses(AF_INET,
+            GAA_FLAG_SKIP_ANYCAST |
+            GAA_FLAG_SKIP_MULTICAST |
+            GAA_FLAG_SKIP_DNS_SERVER |
+            GAA_FLAG_SKIP_FRIENDLY_NAME,
+            NULL,
+            addresses,
+            &length);
+    } while (error == ERROR_BUFFER_OVERFLOW);
+
     if (error != ERROR_SUCCESS) {
-        fprintf(LOG_OUT, "GetAdaptersAddresses() failed: %d\n", WSAGetLastError());
+        fprintf(LOG_OUT, "GetAdaptersAddresses() failed: %d\n", error);
+        free(addresses);
         return false;
     }
 
-    currentAdapter = &addresses;
+    currentAdapter = addresses;
     while (currentAdapter != NULL) {
         // Look for ones that correspond to a ZeroTier device
         if (wcsstr(currentAdapter->Description, L"ZeroTier")) {
@@ -603,6 +908,7 @@ bool FindZeroTierInterfaceAddress(PSOCKADDR_STORAGE addr)
             while (currentAddress != NULL) {
                 if (currentAddress->Address.lpSockaddr->sa_family == AF_INET) {
                     RtlCopyMemory(addr, currentAddress->Address.lpSockaddr, currentAddress->Address.iSockaddrLength);
+                    free(addresses);
                     return true;
                 }
 
@@ -613,9 +919,71 @@ bool FindZeroTierInterfaceAddress(PSOCKADDR_STORAGE addr)
         currentAdapter = currentAdapter->Next;
     }
 
+    free(addresses);
     return false;
 }
 
+bool FindDuplicateDefaultInterfaces(void)
+{
+    PIP_ADAPTER_ADDRESSES addresses;
+    ULONG error;
+    ULONG length;
+    MIB_IPFORWARDROW defaultRoute;
+    PIP_ADAPTER_ADDRESSES currentAdapter;
+    DWORD matchingInterfaces = 0;
+
+    error = GetBestRoute(0, 0, &defaultRoute);
+    if (error != NO_ERROR) {
+        fprintf(LOG_OUT, "GetBestRoute() failed: %d\n", error);
+        return false;
+    }
+
+    addresses = NULL;
+    length = GAA_INITIAL_SIZE;
+    do {
+        free(addresses);
+        addresses = (PIP_ADAPTER_ADDRESSES)malloc(length);
+        if (addresses == NULL) {
+            fprintf(LOG_OUT, "malloc(%u) failed\n", length);
+            return false;
+        }
+
+        // Get all IPv4 interfaces
+        error = GetAdaptersAddresses(AF_INET,
+            GAA_FLAG_SKIP_UNICAST |
+            GAA_FLAG_SKIP_ANYCAST |
+            GAA_FLAG_SKIP_MULTICAST |
+            GAA_FLAG_SKIP_DNS_SERVER |
+            GAA_FLAG_INCLUDE_GATEWAYS |
+            GAA_FLAG_SKIP_FRIENDLY_NAME,
+            NULL,
+            addresses,
+            &length);
+    } while (error == ERROR_BUFFER_OVERFLOW);
+
+    if (error != ERROR_SUCCESS) {
+        fprintf(LOG_OUT, "GetAdaptersAddresses() failed: %d\n", error);
+        free(addresses);
+        return false;
+    }
+
+    currentAdapter = addresses;
+    while (currentAdapter != NULL) {
+        if (currentAdapter->OperStatus == IfOperStatusUp &&
+            currentAdapter->FirstGatewayAddress != NULL &&
+            currentAdapter->FirstGatewayAddress->Address.iSockaddrLength == sizeof(SOCKADDR_IN)) {
+            if (((PSOCKADDR_IN)currentAdapter->FirstGatewayAddress->Address.lpSockaddr)->sin_addr.S_un.S_addr == defaultRoute.dwForwardNextHop) {
+                matchingInterfaces++;
+            }
+        }
+
+        currentAdapter = currentAdapter->Next;
+    }
+
+    free(addresses);
+    return matchingInterfaces > 1;
+}
+
 enum UPnPPortStatus {
     NOT_FOUND,
     OK,
@@ -657,7 +1025,7 @@ UPnPPortStatus UPnPCheckPort(struct UPNPUrls* urls, struct IGDdatas* data, int p
     }
     else if (err == UPNPCOMMAND_SUCCESS) {
         if (!strcmp(myAddr, intClient)) {
-            fprintf(LOG_OUT, "OK\n");
+            fprintf(LOG_OUT, "OK (Internal port: %s)\n", intPort);
             return OK;
         }
         else {
@@ -772,7 +1140,7 @@ bool CheckWANAccess(PSOCKADDR_IN wanAddr, PSOCKADDR_IN reportedWanAddr, bool* fo
         closenatpmp(&natpmp);
 
         if (natPmpErr == 0) {
-            char addrStr[64];
+            char addrStr[INET_ADDRSTRLEN];
             reportedWanAddr->sin_addr = response.pnu.publicaddress.addr;
             inet_ntop(AF_INET, &response.pnu.publicaddress.addr, addrStr, sizeof(addrStr));
             fprintf(LOG_OUT, "%s\n", addrStr);
@@ -799,7 +1167,7 @@ bool CheckWANAccess(PSOCKADDR_IN wanAddr, PSOCKADDR_IN reportedWanAddr, bool* fo
         return false;
     }
     else {
-        char addrStr[64];
+        char addrStr[INET_ADDRSTRLEN];
         inet_ntop(AF_INET, &wanAddr->sin_addr, addrStr, sizeof(addrStr));
         fprintf(LOG_OUT, "%s\n", addrStr);
 
@@ -813,16 +1181,12 @@ bool CheckWANAccess(PSOCKADDR_IN wanAddr, PSOCKADDR_IN reportedWanAddr, bool* fo
     return true;
 }
 
-bool IsPossibleCGN(PSOCKADDR_IN wanAddr)
+bool IsCGN(PSOCKADDR_IN wanAddr)
 {
     DWORD addr = htonl(wanAddr->sin_addr.S_un.S_addr);
 
-    // 10.0.0.0/8 - ISPs used to use this
-    if ((addr & 0xFF000000) == 0x0A000000) {
-        return true;
-    }
     // 100.64.0.0/10 - RFC6598 official CGN address
-    else if ((addr & 0xFFC00000) == 0x64400000) {
+    if ((addr & 0xFFC00000) == 0x64400000) {
         return true;
     }
 
@@ -885,6 +1249,64 @@ int main(int argc, char* argv[])
         return -1;
     }
 
+    if (IsCurrentlyStreaming()) {
+        DisplayMessage("The test cannot proceed because a GameStream session is currently running on this PC.\n\n"
+            "Quit the currently running app on this host within Moonlight, or reboot your PC.");
+        return -1;
+    }
+
+    if (!IsConsoleSessionActive()) {
+        DisplayMessage("The system display is currently locked. You must sign in to your PC again to use GameStream.\n\n"
+            "This is most often due to Microsoft Remote Desktop locking the screen. Use an alternate GameStream-compatible remote desktop solution like Chrome Remote Desktop or TeamViewer to unlock the PC and prevent this error in the future.",
+            "https://github.com/moonlight-stream/moonlight-docs/wiki/Internet-Streaming-Errors#display-locked-error");
+        return -1;
+    }
+
+    fprintf(CONSOLE_OUT, "Checking power settings...\n");
+
+    if (IsSleepEnabled()) {
+        DisplayMessage("This computer has sleep mode enabled. Sleep mode may prevent this PC from being available for streaming.\n\n"
+            "Please ensure sleep is disabled in Power Options so this PC is always ready for streaming. Click the Help button for more information.",
+            "https://github.com/moonlight-stream/moonlight-docs/wiki/Internet-Streaming-Errors#sleep-mode-enabled-warning", MpWarn, false);
+    }
+
+    if (IsHibernationEnabled()) {
+        DisplayMessage("This computer has hibernation enabled. Hibernation may prevent this PC from being available for streaming.\n\n"
+            "Please ensure hibernation is disabled in Power Options so this PC is always ready for streaming. Click the Help button for more information.",
+            "https://github.com/moonlight-stream/moonlight-docs/wiki/Internet-Streaming-Errors#hibernation-enabled-warning", MpWarn, false);
+    }
+
+    fprintf(CONSOLE_OUT, "Checking network connections...\n");
+
+    if (IsLocalNetworkAccessBlocked()) {
+        DisplayMessage("Local network access appears to be blocked by another application installed on this PC.\n\n"
+            "If you have firewall or VPN software installed, make sure it is configured to allow applications to access the local network. Click the Help button for guidance on fixing this issue.",
+            "https://github.com/moonlight-stream/moonlight-docs/wiki/Internet-Streaming-Errors#local-network-access-blocked-error");
+        return -1;
+    }
+
+    if (FindDuplicateDefaultInterfaces()) {
+        DisplayMessage("This computer appears to have more than one connection to the same network (like both WiFi and Ethernet, for example).\n\n"
+            "Please disconnect the extra connection(s) to ensure hosting works reliably over the Internet. If you are connected via WiFi and Ethernet, try disabling your WiFi connection.",
+            "https://github.com/moonlight-stream/moonlight-docs/wiki/Internet-Streaming-Errors#multiple-connections-error", MpWarn, false);
+    }
+
+    fprintf(CONSOLE_OUT, "Checking for anti-virus and firewall software...\n");
+
+    char wmicBuf[8192];
+    if (ExecuteCommand("WMIC /Node:localhost /Namespace:\\\\root\\SecurityCenter2 Path AntiVirusProduct Get displayName", wmicBuf, sizeof(wmicBuf))) {
+        fprintf(LOG_OUT, "AV products:\n%s", wmicBuf);
+    }
+    if (ExecuteCommand("WMIC /Node:localhost /Namespace:\\\\root\\SecurityCenter2 Path FirewallProduct Get displayName", wmicBuf, sizeof(wmicBuf))) {
+        fprintf(LOG_OUT, "Firewall products:\n%s", wmicBuf);
+        if (strstr(wmicBuf, "displayName")) {
+            DisplayMessage("Detected anti-virus and/or firewall software installed on this system. This software may interfere with NVIDIA GameStream.\n\n"
+                "Please try temporarily disabling your anti-virus or firewall software if you experience connection issues with Moonlight.",
+                "https://github.com/moonlight-stream/moonlight-docs/wiki/Troubleshooting#known-application-compatibility-issues", MpInfo, false);
+        }
+    }
+
+
     union {
         SOCKADDR_STORAGE ss;
         SOCKADDR_IN sin;
@@ -950,9 +1372,24 @@ int main(int argc, char* argv[])
         }
     }
 
-    if (!FindLocalInterfaceIPAddress(AF_INET, &ss) && !FindLocalInterfaceIPAddress(AF_INET6, &ss)) {
-        DisplayMessage("Unable to perform GameStream connectivity check. Please check your Internet connection and try again.");
-        return -1;
+    bool hasV4Connectivity, hasV6Connectivity;
+    {
+        SOCKADDR_STORAGE v4, v6;
+
+        hasV4Connectivity = FindLocalInterfaceIPAddress(AF_INET, &v4);
+        hasV6Connectivity = FindLocalInterfaceIPAddress(AF_INET6, &v6);
+
+        // Prefer v4 connectivity because that's what GFE uses natively
+        if (hasV4Connectivity) {
+            ss = v4;
+        }
+        else if (hasV6Connectivity) {
+            ss = v6;
+        }
+        else {
+            DisplayMessage("Unable to perform GameStream connectivity check. Please check your Internet connection and try again.");
+            return -1;
+        }
     }
 
     fprintf(CONSOLE_OUT, "Testing GameStream connectivity on your local network...\n");
@@ -968,7 +1405,7 @@ int main(int argc, char* argv[])
 
     bool igdDisconnected;
     SOCKADDR_IN locallyReportedWanAddr;
-    char wanAddrStr[INET_ADDRSTRLEN];
+    char wanAddrStr[INET6_ADDRSTRLEN];
 
     if (ss.ss_family == AF_INET) {
         bool rulesFound;
@@ -979,8 +1416,6 @@ int main(int argc, char* argv[])
             return -1;
         }
 
-        fprintf(CONSOLE_OUT, "Testing GameStream connectivity over the Internet...\n");
-
         // Detect a double NAT by detecting STUN and and UPnP mismatches
         if (sin.sin_addr.S_un.S_addr != locallyReportedWanAddr.sin_addr.S_un.S_addr) {
             fprintf(LOG_OUT, "Testing GameStream ports via UPnP/NAT-PMP reported WAN address\n");
@@ -998,101 +1433,121 @@ int main(int argc, char* argv[])
         // Go directly to the relay check if we have only IPv6 connectivity
         igdDisconnected = false;
         locallyReportedWanAddr = {};
-        goto RelayCheck;
     }
 
-    // Try to connect via WAN IPv4 address
-    fprintf(LOG_OUT, "Testing GameStream ports via STUN-reported WAN address\n");
-    if (!TestAllPorts(&ss, portMsgBuf, sizeof(portMsgBuf), false, true)) {
-    RelayCheck:
-        struct addrinfo hint = {};
-        struct addrinfo* result;
+    struct addrinfo hint = {};
+    struct addrinfo* result;
 
-        // We can get here if the router doesn't support NAT reflection.
-        // We'll need to call out to our loopback server to get a second opinion.
+    hint.ai_family = AF_UNSPEC;
+    hint.ai_flags = AI_ADDRCONFIG;
+    err = getaddrinfo("loopback-v2.moonlight-stream.org", NULL, &hint, &result);
+    if (err != 0 || result == NULL) {
+        fprintf(LOG_OUT, "getaddrinfo() failed: %d\n", err);
+    }
+    else {
+        bool testServerWasReachable = false;
+        bool allPortsFailedOnV4 = true;
 
-        hint.ai_family = AF_UNSPEC;
-        hint.ai_flags = AI_ADDRCONFIG;
-        err = getaddrinfo("loopback.moonlight-stream.org", NULL, &hint, &result);
-        if (err != 0 || result == NULL) {
-            fprintf(LOG_OUT, "getaddrinfo() failed: %d\n", err);
+        // First try the relay server over IPv4. If this passes, it's considered a full success
+        fprintf(LOG_OUT, "Testing GameStream ports via IPv4 loopback server\n");
+        for (struct addrinfo* current = result; current != NULL; current = current->ai_next) {
+            if (current->ai_family == AF_INET) {
+                fprintf(CONSOLE_OUT, "Testing GameStream connectivity over the Internet using a relay server...\n");
+
+                if (!IsTestServerReachable(current, 443)) {
+                    fprintf(CONSOLE_OUT, "Skipping unreachable relay server...\n");
+                    continue;
+                }
+
+                testServerWasReachable = true;
+
+                if (TestAllPorts((PSOCKADDR_STORAGE)current->ai_addr, portMsgBuf, sizeof(portMsgBuf), true, true, &allPortsFailedOnV4)) {
+                    freeaddrinfo(result);
+                    snprintf(msgBuf, sizeof(msgBuf), "This PC is ready to host over the Internet!\n\n"
+                        "For the easiest setup, you should pair Moonlight to your gaming PC from your home network before trying to stream over the Internet.\n\n"
+                        "If you can't, you can type the following address into Moonlight's Add PC dialog: %s", wanAddrStr);
+                    DisplayMessage(msgBuf, nullptr, MpInfo);
+                    return 0;
+                }
+                else {
+                    // Tested against a working server and it failed
+                    break;
+                }
+            }
         }
-        else {
-            bool allPortsFailedOnV4 = true;
 
-            // First try the relay server over IPv4. If this passes, it's considered a full success
-            fprintf(LOG_OUT, "Testing GameStream ports via IPv4 loopback server\n");
-            for (struct addrinfo* current = result; current != NULL; current = current->ai_next) {
-                if (current->ai_family == AF_INET) {
-                    fprintf(CONSOLE_OUT, "Testing GameStream connectivity over the Internet using a relay server...\n");
-                    if (TestAllPorts((PSOCKADDR_STORAGE)current->ai_addr, portMsgBuf, sizeof(portMsgBuf), true, true, &allPortsFailedOnV4)) {
+        // If that fails, try the relay server over IPv6. If this passes, it will be a partial success
+        fprintf(LOG_OUT, "Testing GameStream ports via IPv6 loopback server\n");
+        for (struct addrinfo* current = result; current != NULL; current = current->ai_next) {
+            if (current->ai_family == AF_INET6) {
+                fprintf(CONSOLE_OUT, "Testing GameStream connectivity over the Internet using an IPv6 relay server...\n");
+
+                if (!IsTestServerReachable(current, 443)) {
+                    fprintf(CONSOLE_OUT, "Skipping unreachable IPv6 relay server...\n");
+                    continue;
+                }
+
+                testServerWasReachable = true;
+
+                // Pass the portMsgBuf only if we've detected an IPv6-only setup. Otherwise, we want to preserve
+                // the failing ports from the IPv4 to display in the error dialog.
+                if (TestAllPorts((PSOCKADDR_STORAGE)current->ai_addr,
+                                    ss.ss_family == AF_INET6 ? portMsgBuf : NULL,
+                                    ss.ss_family == AF_INET6 ? sizeof(portMsgBuf) : 0, true, true)) {
+                    // We will terminate the test at the IPv6 limited connectivity warning in the following cases:
+                    // 1) Double-NAT/CGN - indicates the connection is fundamentally limited to IPv6 for end-to-end connectivity
+                    // 2) IPv6-only - indicates the connection is fundamentally limited to IPv6 for all connectivity
+                    // 3) All ports failed the test with our IPv4 relay - This is one final heuristic to weed out IPv4 misconfigurations. If we have some ports open,
+                    //                                                    it clearly indicates IPv4 support is possible, just currently misconfigured.
+                    //
+                    // Our last (implicit) heuristic is that we actually managed to establish an IPv6 connection. This means that there was either
+                    // no IPv6 firewall (hopefully not) or that we were able to talk to a PCP/IGDv6 gateway to allow us through. Hopefully if we have
+                    // a gateway that is unresponsive to UPnP/NAT-PMP, we wouldn't even be able to establish this connection so we would inherently fall
+                    // to the checks below for IPv4 issues.
+                    if (IsDoubleNAT(&locallyReportedWanAddr) || igdDisconnected || IsCGN(&locallyReportedWanAddr) || ss.ss_family == AF_INET6 || allPortsFailedOnV4) {
+                        snprintf(msgBuf, sizeof(msgBuf), "This PC has limited connectivity for Internet hosting. It will work only for clients on certain networks.\n\n"
+                            "If you want to try streaming with this configuration, you must pair Moonlight to your gaming PC from your home network before trying to stream over the Internet.\n\n"
+                            "To get full connectivity, please contact your ISP and ask for a \"public IPv4 address\" which they may offer for free upon request. For more information and workarounds, click the Help button.");
+                        DisplayMessage(msgBuf, "https://github.com/moonlight-stream/moonlight-docs/wiki/Internet-Streaming-Errors#limited-connectivity-for-hosting-error", MpWarn);
                         freeaddrinfo(result);
-                        goto AllTestsPassed;
+                        return 0;
                     }
                 }
+
+                // Tested against a IPv6 working server
+                break;
             }
-
-            // If that fails, try the relay server over IPv6. If this passes, it will be a partial success
-            fprintf(LOG_OUT, "Testing GameStream ports via IPv6 loopback server\n");
-            for (struct addrinfo* current = result; current != NULL; current = current->ai_next) {
-                if (current->ai_family == AF_INET6) {
-                    fprintf(CONSOLE_OUT, "Testing GameStream connectivity over the Internet using an IPv6 relay server...\n");
-                    // Pass the portMsgBuf only if we've detected an IPv6-only setup. Otherwise, we want to preserve
-                    // the failing ports from the IPv4 to display in the error dialog.
-                    if (TestAllPorts((PSOCKADDR_STORAGE)current->ai_addr,
-                                     ss.ss_family == AF_INET6 ? portMsgBuf : NULL,
-                                     ss.ss_family == AF_INET6 ? sizeof(portMsgBuf) : 0, true, true)) {
-                        // We will terminate the test at the IPv6 limited connectivity warning in the following cases:
-                        // 1) Double-NAT/CGN - indicates the connection is fundamentally limited to IPv6 for end-to-end connectivity
-                        // 2) IPv6-only - indicates the connection is fundamentally limited to IPv6 for all connectivity
-                        // 3) All ports failed the test with our IPv4 relay - This is one final heuristic to weed out IPv4 misconfigurations. If we have some ports open,
-                        //                                                    it clearly indicates IPv4 support is possible, just currently misconfigured.
-                        //
-                        // Our last (implicit) heuristic is that we actually managed to establish an IPv6 connection. This means that there was either
-                        // no IPv6 firewall (hopefully not) or that we were able to talk to a PCP/IGDv6 gateway to allow us through. Hopefully if we have
-                        // a gateway that is unresponsive to UPnP/NAT-PMP, we wouldn't even be able to establish this connection so we would inherently fall
-                        // to the checks below for IPv4 issues.
-                        if (IsDoubleNAT(&locallyReportedWanAddr) || igdDisconnected || IsPossibleCGN(&locallyReportedWanAddr) || ss.ss_family == AF_INET6 || allPortsFailedOnV4) {
-                            snprintf(msgBuf, sizeof(msgBuf), "This PC has limited connectivity for Internet hosting. It will work only for clients on certain networks.\n\n"
-                                "If you want to try streaming with this configuration, you must pair Moonlight to your gaming PC from your home network before trying to stream over the Internet.\n\n"
-                                "To get full connectivity, please contact your ISP and ask for a \"public IP address\" which they may offer for free upon request. For more information and workarounds, click the Help button.");
-                            DisplayMessage(msgBuf, "https://github.com/moonlight-stream/moonlight-docs/wiki/Internet-Streaming-Errors#limited-connectivity-for-hosting-error", MpWarn);
-                            freeaddrinfo(result);
-                            return 0;
-                        }
-                    }
-                }
-            }
-
-            freeaddrinfo(result);
         }
 
-        // Many UPnP devices report IGD disconnected when double-NATed. If it was really offline,
-        // we probably would not have even gotten past STUN.
-        if (IsDoubleNAT(&locallyReportedWanAddr) || igdDisconnected) {
-            snprintf(msgBuf, sizeof(msgBuf), "Your router appears be connected to the Internet through another router. Click the Help button for guidance on fixing this issue.");
-            DisplayMessage(msgBuf, "https://github.com/moonlight-stream/moonlight-docs/wiki/Internet-Streaming-Errors#connected-through-another-router-error");
-        }
-        else if (IsPossibleCGN(&locallyReportedWanAddr)) {
-            snprintf(msgBuf, sizeof(msgBuf), "Your ISP is running a Carrier-Grade NAT that is preventing you from hosting services like Moonlight on the Internet.\n\n"
-                "Ask your ISP for a \"public IP address\" which they may offer for free upon request. For more information and workarounds, click the Help button.");
-            DisplayMessage(msgBuf, "https://github.com/moonlight-stream/moonlight-docs/wiki/Internet-Streaming-Errors#carrier-grade-nat-error");
-        }
-        else {
-            snprintf(msgBuf, sizeof(msgBuf), "Internet GameStream connectivity check failed.\n\n"
-                "Check that UPnP is enabled in your router settings. For more information and workarounds, click the Help button.\n\n"
-                "The following ports were not forwarded properly:\n%s", portMsgBuf);
-            DisplayMessage(msgBuf, "https://github.com/moonlight-stream/moonlight-docs/wiki/Internet-Streaming-Errors#internet-gamestream-connectivity-check-error");
-        }
+        freeaddrinfo(result);
 
-        return -1;
+        if (!testServerWasReachable) {
+            snprintf(msgBuf, sizeof(msgBuf), "None of Moonlight's connection testing servers were reachable from your PC. Check your Internet connection and try again later.");
+            DisplayMessage(msgBuf);
+            return 0;
+        }
+    }
+    // Many UPnP devices report IGD disconnected when double-NATed. If it was really offline,
+    // we probably would not have even gotten past STUN.
+    //
+    // We try to tell double-NAT from CGN by checking if IPv6 connectivity is available. If it
+    // is, we assume we're in a DS-Lite or similar configuration. If not, we'll assume it's a
+    // real double-NAT setup.
+    if (IsCGN(&locallyReportedWanAddr) || ((IsDoubleNAT(&locallyReportedWanAddr) || igdDisconnected) && hasV6Connectivity)) {
+        snprintf(msgBuf, sizeof(msgBuf), "Your ISP is running a Carrier-Grade NAT that is preventing you from hosting services like Moonlight on the Internet.\n\n"
+            "Ask your ISP for a \"public IPv4 address\" which they may offer for free upon request. For more information and workarounds, click the Help button.");
+        DisplayMessage(msgBuf, "https://github.com/moonlight-stream/moonlight-docs/wiki/Internet-Streaming-Errors#carrier-grade-nat-error");
+    }
+    else if ((IsDoubleNAT(&locallyReportedWanAddr) || igdDisconnected) /* && !hasV6Connectivity */) {
+        snprintf(msgBuf, sizeof(msgBuf), "Your router appears be connected to the Internet through another router. Click the Help button for guidance on fixing this issue.");
+        DisplayMessage(msgBuf, "https://github.com/moonlight-stream/moonlight-docs/wiki/Internet-Streaming-Errors#connected-through-another-router-error");
+    }
+    else {
+        snprintf(msgBuf, sizeof(msgBuf), "Internet GameStream connectivity check failed.\n\n"
+            "First, try restarting your router. If that fails, check that UPnP is enabled in your router settings. For more information and workarounds, click the Help button.\n\n"
+            "The following ports were not forwarded properly:\n%s", portMsgBuf);
+        DisplayMessage(msgBuf, "https://github.com/moonlight-stream/moonlight-docs/wiki/Internet-Streaming-Errors#internet-gamestream-connectivity-check-error");
     }
 
-AllTestsPassed:
-    snprintf(msgBuf, sizeof(msgBuf), "This PC is ready to host over the Internet!\n\n"
-        "For the easiest setup, you should pair Moonlight to your gaming PC from your home network before trying to stream over the Internet.\n\n"
-        "If you can't, you can type the following address into Moonlight's Add PC dialog: %s", wanAddrStr);
-    DisplayMessage(msgBuf, nullptr, MpInfo);
-
-    return 0;
+    return -1;
 }

mist/mist.exe.manifest

@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<assembly xmlns="urn:schemas-microsoft-com:asm.v1" xmlns:asmv3="urn:schemas-microsoft-com:asm.v3" manifestVersion="1.0">
+    <compatibility xmlns="urn:schemas-microsoft-com:compatibility.v1">
+        <application>
+            <!-- Windows 10 -->
+            <supportedOS Id="{8e0f7a12-bfb3-4fe8-b9a5-48fd50a15a9a}"/>
+            <!-- Windows 8.1 -->
+            <supportedOS Id="{1f676c76-80e1-4239-95bb-83d0f6d0da78}"/>
+            <!-- Windows 8 -->
+            <supportedOS Id="{4a2f28e3-53b9-4441-ba9c-d69d4a4a6e38}"/>
+            <!-- Windows 7 -->
+            <supportedOS Id="{35138b9a-5d96-4fbd-8e2d-a2440225f93a}"/>
+            <!-- Windows Vista -->
+            <supportedOS Id="{e2011457-1546-43c5-a5fe-008deee3d3f0}"/>
+        </application> 
+    </compatibility>
+</assembly>

mist/mist.vcxproj

@@ -100,6 +100,9 @@
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <AdditionalLibraryDirectories>..\libs\x86\Debug;%(AdditionalLibraryDirectories)</AdditionalLibraryDirectories>
     </Link>
+    <Manifest>
+      <AdditionalManifestFiles>mist.exe.manifest</AdditionalManifestFiles>
+    </Manifest>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
     <ClCompile>
@@ -115,6 +118,9 @@
       <SubSystem>Console</SubSystem>
       <GenerateDebugInformation>true</GenerateDebugInformation>
     </Link>
+    <Manifest>
+      <AdditionalManifestFiles>mist.exe.manifest</AdditionalManifestFiles>
+    </Manifest>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'">
     <ClCompile>
@@ -138,6 +144,9 @@
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <AdditionalLibraryDirectories>..\libs\x86\Release;%(AdditionalLibraryDirectories)</AdditionalLibraryDirectories>
     </Link>
+    <Manifest>
+      <AdditionalManifestFiles>mist.exe.manifest</AdditionalManifestFiles>
+    </Manifest>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'">
     <ClCompile>
@@ -157,6 +166,9 @@
       <OptimizeReferences>true</OptimizeReferences>
       <GenerateDebugInformation>true</GenerateDebugInformation>
     </Link>
+    <Manifest>
+      <AdditionalManifestFiles>mist.exe.manifest</AdditionalManifestFiles>
+    </Manifest>
   </ItemDefinitionGroup>
   <ItemGroup>
     <ClCompile Include="mist.cpp" />
@@ -169,6 +181,9 @@
     <ClInclude Include="..\version.h" />
     <ClInclude Include="mist.h" />
   </ItemGroup>
+  <ItemGroup>
+    <Manifest Include="mist.exe.manifest" />
+  </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
   <ImportGroup Label="ExtensionTargets">
   </ImportGroup>

mist/mist.vcxproj.filters

@@ -35,4 +35,9 @@
       <Filter>Source Files</Filter>
     </ResourceCompile>
   </ItemGroup>
+  <ItemGroup>
+    <Manifest Include="mist.exe.manifest">
+      <Filter>Resource Files</Filter>
+    </Manifest>
+  </ItemGroup>
 </Project>

mist/stun.cpp

@@ -4,7 +4,7 @@
 
 #define STUN_PORT 3478
 
-#define STUN_RECV_TIMEOUT_SEC 3
+#define STUN_RECV_TIMEOUT_SEC 5
 
 #define STUN_MESSAGE_BINDING_REQUEST 0x0001
 #define STUN_MESSAGE_BINDING_SUCCESS 0x0101
@@ -44,18 +44,21 @@ bool getExternalAddressPortIP4(unsigned short localPort, PSOCKADDR_IN wanAddr)
     STUN_MESSAGE reqMsg;
     int i;
     int bytesRead;
-    int tries;
-    int timeout;
     int err;
+    bool ret;
     PSTUN_ATTRIBUTE_HEADER attribute;
     PSTUN_MAPPED_IPV4_ADDRESS_ATTRIBUTE ipv4Attrib;
     struct addrinfo* result;
     struct addrinfo hints;
+    struct sockaddr_in bindAddr;
     union {
         STUN_MESSAGE hdr;
         char buf[1024];
     } resp;
 
+    sock = INVALID_SOCKET;
+    ret = false;
+
     memset(&hints, 0, sizeof(hints));
     hints.ai_family = AF_INET;
     hints.ai_flags = AI_ADDRCONFIG;
@@ -70,18 +73,15 @@ bool getExternalAddressPortIP4(unsigned short localPort, PSOCKADDR_IN wanAddr)
     sock = socket(hints.ai_family, hints.ai_socktype, hints.ai_protocol);
     if (sock == INVALID_SOCKET) {
         fprintf(LOG_OUT, "socket() failed: %d\n", WSAGetLastError());
-        freeaddrinfo(result);
-        return false;
+        goto Exit;
     }
 
-    struct sockaddr_in bindAddr = {};
+    bindAddr = {};
     bindAddr.sin_family = hints.ai_family;
     bindAddr.sin_port = htons(localPort);
     if (bind(sock, (struct sockaddr*)&bindAddr, sizeof(bindAddr)) == SOCKET_ERROR) {
         fprintf(LOG_OUT, "bind() failed: %d\n", WSAGetLastError());
-        closesocket(sock);
-        freeaddrinfo(result);
-        return false;
+        goto Exit;
     }
 
     reqMsg.messageType = htons(STUN_MESSAGE_BINDING_REQUEST);
@@ -100,57 +100,60 @@ bool getExternalAddressPortIP4(unsigned short localPort, PSOCKADDR_IN wanAddr)
             }
         }
 
-        fd_set fds;
-        FD_ZERO(&fds);
-        FD_SET(sock, &fds);
+        for (;;) {
+            fd_set fds;
+            FD_ZERO(&fds);
+            FD_SET(sock, &fds);
 
-        struct timeval tv;
-        tv.tv_sec = 1;
-        tv.tv_usec = 0;
+            struct timeval tv;
+            tv.tv_sec = 1;
+            tv.tv_usec = 0;
 
-        int selectRes = select(0, &fds, nullptr, nullptr, &tv);
-        if (selectRes == 0) {
-            // Timeout - continue looping
-            continue;
+            int selectRes = select(0, &fds, nullptr, nullptr, &tv);
+            if (selectRes == 0) {
+                // Timeout - break to the enclosing loop
+                break;
+            }
+            else if (selectRes == SOCKET_ERROR) {
+                fprintf(LOG_OUT, "select() failed: %d\n", WSAGetLastError());
+                goto Exit;
+            }
+
+            // recvfrom() will return WSAECONNRESET if the socket has received an ICMP Port Unreachable
+            // message from one of the IP addresses we've attempted communication with. The socket is still
+            // operable (and may even contain queued messages to receive). We should ignore that error and
+            // continue reading, otherwise exit the loop.
+            bytesRead = recvfrom(sock, resp.buf, sizeof(resp.buf), 0, NULL, NULL);
+            if (bytesRead != SOCKET_ERROR || WSAGetLastError() != WSAECONNRESET) {
+                goto RecvDone;
+            }
         }
-        else if (selectRes == SOCKET_ERROR) {
-            fprintf(LOG_OUT, "select() failed: %d\n", WSAGetLastError());
-            closesocket(sock);
-            freeaddrinfo(result);
-            return false;
-        }
-
-        // Error handling is below
-        bytesRead = recvfrom(sock, resp.buf, sizeof(resp.buf), 0, NULL, NULL);
-        break;
     }
 
-    freeaddrinfo(result);
-    closesocket(sock);
-
+RecvDone:
     if (bytesRead == 0) {
         fprintf(LOG_OUT, "No response from STUN server\n");
-        return false;
+        goto Exit;
     }
     else if (bytesRead == SOCKET_ERROR) {
         fprintf(LOG_OUT, "Failed to read STUN binding response: %d\n", WSAGetLastError());
-        return false;
+        goto Exit;
     }
     else if (bytesRead < sizeof(resp.hdr)) {
         fprintf(LOG_OUT, "STUN message truncated: %d\n", bytesRead);
-        return false;
+        goto Exit;
     }
     else if (htonl(resp.hdr.magicCookie) != STUN_MESSAGE_COOKIE) {
         fprintf(LOG_OUT, "Bad STUN cookie value: %x\n", htonl(resp.hdr.magicCookie));
-        return false;
+        goto Exit;
     }
     else if (memcmp(reqMsg.transactionId, resp.hdr.transactionId, sizeof(reqMsg.transactionId))) {
         fprintf(LOG_OUT, "STUN transaction ID mismatch\n");
-        return false;
+        goto Exit;
     }
     else if (htons(resp.hdr.messageType) != STUN_MESSAGE_BINDING_SUCCESS) {
         fprintf(LOG_OUT, "STUN message type mismatch: %x\n", htons(resp.hdr.messageType));
-        return false;
+        goto Exit;
     }
 
     attribute = (PSTUN_ATTRIBUTE_HEADER)(&resp.hdr + 1);
@@ -158,7 +161,7 @@ bool getExternalAddressPortIP4(unsigned short localPort, PSOCKADDR_IN wanAddr)
     while (bytesRead > sizeof(*attribute)) {
         if (bytesRead < sizeof(*attribute) + htons(attribute->length)) {
             fprintf(LOG_OUT, "STUN attribute out of bounds: %d\n", htons(attribute->length));
-            return false;
+            goto Exit;
         }
         // Mask off the comprehension bit
         else if ((htons(attribute->type) & 0x7FFF) != STUN_ATTRIBUTE_XOR_MAPPED_ADDRESS) {
@@ -171,11 +174,11 @@ bool getExternalAddressPortIP4(unsigned short localPort, PSOCKADDR_IN wanAddr)
         ipv4Attrib = (PSTUN_MAPPED_IPV4_ADDRESS_ATTRIBUTE)attribute;
         if (htons(ipv4Attrib->hdr.length) != 8) {
             fprintf(LOG_OUT, "STUN address length mismatch: %d\n", htons(ipv4Attrib->hdr.length));
-            return false;
+            goto Exit;
         }
         else if (ipv4Attrib->addressFamily != 1) {
             fprintf(LOG_OUT, "STUN address family mismatch: %x\n", ipv4Attrib->addressFamily);
-            return false;
+            goto Exit;
         }
 
         *wanAddr = {};
@@ -185,9 +188,20 @@ bool getExternalAddressPortIP4(unsigned short localPort, PSOCKADDR_IN wanAddr)
         wanAddr->sin_port = ipv4Attrib->port ^ (short)resp.hdr.magicCookie;
         wanAddr->sin_addr.S_un.S_addr = ipv4Attrib->address ^ resp.hdr.magicCookie;
 
-        return true;
+        ret = true;
+        goto Exit;
     }
 
     fprintf(LOG_OUT, "No XOR mapped address found in STUN response!\n");
-    return false;
+
+Exit:
+    if (sock != INVALID_SOCKET) {
+        closesocket(sock);
+    }
+
+    if (result != NULL) {
+        freeaddrinfo(result);
+    }
+
+    return ret;
 }

version.h

@@ -1,7 +1,7 @@
 #pragma once
 
-#define VER_VERSION                 4,2,0,0
-#define VER_VERSION_STR             "4.2.0.0"
+#define VER_VERSION                 5,4,0,0
+#define VER_VERSION_STR             "5.4.0.0"
 
 #define VER_COMPANYNAME_STR         "Moonlight Game Streaming Project"
 #define VER_PRODUCTNAME_STR         "Moonlight Internet Hosting Tool"