troubleshooter: detect lack of ipv4 (#447)

## Link to GitHub Issue, if one exists
#345 

## Description of change
Most games will fail show a network error if there is no network adapter
with a valid IPv4 address

Detect this case in netfix code and show a warning message in log +
deferred error message.

## Testing
Tested with no network adapters, with IPv6 only adapter, and a
disconnected NIC.

src/spice2x/hooks/networkhook.cpp

@@ -4,6 +4,7 @@
 #include <iphlpapi.h>
 #include <stdlib.h>
 #include <string>
+#include <mutex>
 
 #include "avs/core.h"
 #include "avs/ea3.h"
@@ -12,6 +13,7 @@
 #include "util/detour.h"
 #include "util/fileutils.h"
 #include "util/libutils.h"
+#include "util/deferlog.h"
 
 // hooking related stuff
 static decltype(GetAdaptersInfo) *GetAdaptersInfo_orig = nullptr;
@@ -27,6 +29,19 @@ static struct in_addr network;
 static struct in_addr prefix;
 static struct in_addr subnet;
 
+static void defer_network_adapter_error() {
+    static std::once_flag printed;
+    std::call_once(printed, []() {
+        deferredlogs::defer_error_messages({
+            "network adapter issue detected!",
+            "    ensure you have at least one network adapter with a valid IPv4 address",
+            "    the IPv4 address can be external or internal, it just needs to be valid",
+            "    the network adapter can be a wired or wireless connection",
+            "    you still need to do this even if you are connecting to a local server!",
+            });
+    });
+}
+
 static ULONG WINAPI GetAdaptersInfo_hook(PIP_ADAPTER_INFO pAdapterInfo, PULONG pOutBufLen) {
 
     // call orig
@@ -53,6 +68,15 @@ static ULONG WINAPI GetAdaptersInfo_hook(PIP_ADAPTER_INFO pAdapterInfo, PULONG p
             free(pAdapterInfo2);
         }
 
+        if (ret != ERROR_SUCCESS) {
+            defer_network_adapter_error();
+            log_warning(
+                "network",
+                "GetAdaptersInfo failed with {}; "
+                "check if you have at least one network adapter with a valid IPv4 address!",
+                ret);
+        }
+
         return ret;
     }
 
@@ -101,8 +125,13 @@ static ULONG WINAPI GetAdaptersInfo_hook(PIP_ADAPTER_INFO pAdapterInfo, PULONG p
         free(pIpForwardTable);
         pIpForwardTable = (MIB_IPFORWARDTABLE *) malloc(dwSize);
     }
-    if (GetIpForwardTable(pIpForwardTable, &dwSize, 1) != NO_ERROR || pIpForwardTable->dwNumEntries == 0)
+    if (GetIpForwardTable(pIpForwardTable, &dwSize, 1) != NO_ERROR || pIpForwardTable->dwNumEntries == 0) {
+        defer_network_adapter_error();
+        if (GetAdaptersInfo_log) {
+            log_warning("network", "GetIpForwardTable failed");
+        }
         return ret;
+    }
 
     // determine best interface
     DWORD best = pIpForwardTable->table[0].dwForwardIfIndex;
@@ -134,6 +163,20 @@ static ULONG WINAPI GetAdaptersInfo_hook(PIP_ADAPTER_INFO pAdapterInfo, PULONG p
         info = info->Next;
     }
 
+    if (pAdapterInfo->IpAddressList.IpAddress.String[0] == 0 ||
+        pAdapterInfo->IpAddressList.IpAddress.String[0] == '0') {
+        defer_network_adapter_error();
+        if (GetAdaptersInfo_log) {
+            log_warning(
+                "network",
+                "invalid IPv4 address for adapter {}, {} = {}; "
+                "ensure you have at least one network adapter with valid IPv4 address!",
+                pAdapterInfo->AdapterName,
+                pAdapterInfo->Description,
+                pAdapterInfo->IpAddressList.IpAddress.String);
+        }
+    }
+
     // return original value
     GetAdaptersInfo_log = false;
     return ret;