From 3fe4b41f201c2d3c10a10c5e45d989be4930b2f2 Mon Sep 17 00:00:00 2001
From: Eric Kohl <eric.kohl@reactos.org>
Date: Fri, 18 Apr 2025 19:51:59 +0200
Subject: [PATCH] [IPHLPAPI] Retrieve DHCP information from the registry

---
 dll/win32/iphlpapi/dhcp.h          |   9 ++-
 dll/win32/iphlpapi/dhcp_reactos.c  | 107 ++++++++++++++++++++++-------
 dll/win32/iphlpapi/iphlpapi_main.c |   9 +--
 3 files changed, 88 insertions(+), 37 deletions(-)

diff --git a/dll/win32/iphlpapi/dhcp.h b/dll/win32/iphlpapi/dhcp.h
index ba98fb62f09..0a42be2a91b 100644
--- a/dll/win32/iphlpapi/dhcp.h
+++ b/dll/win32/iphlpapi/dhcp.h
@@ -9,10 +9,9 @@
 #ifndef WINE_DHCP_H_
 #define WINE_DHCP_H_
 
-DWORD getDhcpInfoForAdapter(DWORD AdapterIndex,
-                            PBOOL DhcpEnabled,
-                            PDWORD DhcpServer,
-                            time_t *LeaseObtained,
-                            time_t *LeaseExpires);
+DWORD
+getDhcpInfoForAdapter(
+    DWORD AdapterIndex,
+    PIP_ADAPTER_INFO ptr);
 
 #endif /* ndef WINE_DHCP_H_ */
diff --git a/dll/win32/iphlpapi/dhcp_reactos.c b/dll/win32/iphlpapi/dhcp_reactos.c
index ecfedda9e97..f544f50bb90 100644
--- a/dll/win32/iphlpapi/dhcp_reactos.c
+++ b/dll/win32/iphlpapi/dhcp_reactos.c
@@ -8,35 +8,94 @@
 
 #include "iphlpapi_private.h"
 
-DWORD APIENTRY DhcpRosGetAdapterInfo(DWORD AdapterIndex,
-                                     PBOOL DhcpEnabled,
-                                     PDWORD DhcpServer,
-                                     time_t *LeaseObtained,
-                                     time_t *LeaseExpires);
-
-DWORD getDhcpInfoForAdapter(DWORD AdapterIndex,
-                            PBOOL DhcpEnabled,
-                            PDWORD DhcpServer,
-                            time_t *LeaseObtained,
-                            time_t *LeaseExpires)
+DWORD
+getDhcpInfoForAdapter(
+    DWORD AdapterIndex,
+    PIP_ADAPTER_INFO ptr)
 {
-    DWORD Status, Version = 0;
+    const char *ifname = NULL;
+    HKEY hKeyInterfaces = NULL, hKeyInterface = NULL;
+    DWORD dwValue, dwSize, dwType;
+    DWORD ret = ERROR_SUCCESS;
 
-    Status = DhcpCApiInitialize(&Version);
-    if (Status != ERROR_SUCCESS)
+    ptr->DhcpEnabled = 0;
+    ptr->LeaseObtained = 0;
+    ptr->LeaseExpires = 0;
+    strcpy(ptr->DhcpServer.IpAddress.String, "");
+
+    ifname = getInterfaceNameByIndex(AdapterIndex);
+    if (!ifname)
+        return ERROR_OUTOFMEMORY;
+
+    ret = RegOpenKeyExW(HKEY_LOCAL_MACHINE,
+                        L"SYSTEM\\CurrentControlSet\\Services\\Tcpip\\Parameters\\Interfaces",
+                        0,
+                        KEY_READ,
+                        &hKeyInterfaces);
+    if (ret != ERROR_SUCCESS)
+        goto done;
+
+    ret = RegOpenKeyExA(hKeyInterfaces,
+                        ifname,
+                        0,
+                        KEY_READ,
+                        &hKeyInterface);
+    if (ret != ERROR_SUCCESS)
+        goto done;
+
+    dwSize = sizeof(ptr->DhcpEnabled);
+    ret = RegQueryValueExW(hKeyInterface,
+                           L"EnableDHCP",
+                           NULL,
+                           &dwType,
+                           (PBYTE)&ptr->DhcpEnabled,
+                           &dwSize);
+    if (ret != ERROR_SUCCESS)
+        ptr->DhcpEnabled = 0;
+
+    if (ptr->DhcpEnabled != 0)
     {
-        /* We assume that the DHCP service isn't running yet */
-        *DhcpEnabled = FALSE;
-        *DhcpServer = htonl(INADDR_NONE);
-        *LeaseObtained = 0;
-        *LeaseExpires = 0;
-        return ERROR_SUCCESS;
+        dwSize = sizeof(ptr->LeaseObtained);
+        ret = RegQueryValueExW(hKeyInterface,
+                               L"LeaseObtainedTime",
+                               NULL,
+                               &dwType,
+                               (PBYTE)&dwValue,
+                               &dwSize);
+        if (ret == ERROR_SUCCESS)
+            ptr->LeaseObtained = (time_t)dwValue;
+
+        dwSize = sizeof(dwValue);
+        ret = RegQueryValueExW(hKeyInterface,
+                               L"LeaseTerminatesTime",
+                               NULL,
+                               &dwType,
+                               (PBYTE)&dwValue,
+                               &dwSize);
+        if (ret == ERROR_SUCCESS)
+            ptr->LeaseExpires = (time_t)dwValue;
+
+        dwSize = sizeof(ptr->DhcpServer.IpAddress.String);
+        ret = RegQueryValueExA(hKeyInterface,
+                               "DhcpServer",
+                               NULL,
+                               &dwType,
+                               (PBYTE)&ptr->DhcpServer.IpAddress.String,
+                               &dwSize);
+        if (ret != ERROR_SUCCESS)
+            strcpy(ptr->DhcpServer.IpAddress.String, "");
     }
+    ret = ERROR_SUCCESS;
 
-    Status = DhcpRosGetAdapterInfo(AdapterIndex, DhcpEnabled, DhcpServer,
-                                   LeaseObtained, LeaseExpires);
+done:
+    if (hKeyInterface)
+        RegCloseKey(hKeyInterface);
 
-    DhcpCApiCleanup();
+    if (hKeyInterfaces)
+        RegCloseKey(hKeyInterfaces);
 
-    return Status;
+    if (ifname)
+        consumeInterfaceName(ifname);
+
+    return ret;
 }
diff --git a/dll/win32/iphlpapi/iphlpapi_main.c b/dll/win32/iphlpapi/iphlpapi_main.c
index a2fccb2cf58..8ebd354b1d5 100644
--- a/dll/win32/iphlpapi/iphlpapi_main.c
+++ b/dll/win32/iphlpapi/iphlpapi_main.c
@@ -686,8 +686,6 @@ DWORD WINAPI GetAdapterIndex(LPWSTR AdapterName, PULONG IfIndex)
 DWORD WINAPI GetAdaptersInfo(PIP_ADAPTER_INFO pAdapterInfo, PULONG pOutBufLen)
 {
   DWORD ret;
-  BOOL dhcpEnabled;
-  DWORD dhcpServer;
 
   TRACE("pAdapterInfo %p, pOutBufLen %p\n", pAdapterInfo, pOutBufLen);
   if (!pOutBufLen)
@@ -771,12 +769,7 @@ DWORD WINAPI GetAdaptersInfo(PIP_ADAPTER_INFO pAdapterInfo, PULONG pOutBufLen)
               ptr->IpAddressList.Context = ptr->Index;
               toIPAddressString(getInterfaceGatewayByIndex(table->indexes[ndx]),
                ptr->GatewayList.IpAddress.String);
-              getDhcpInfoForAdapter(table->indexes[ndx], &dhcpEnabled,
-                                    &dhcpServer, &ptr->LeaseObtained,
-                                    &ptr->LeaseExpires);
-              ptr->DhcpEnabled = (DWORD) dhcpEnabled;
-              toIPAddressString(dhcpServer,
-                                ptr->DhcpServer.IpAddress.String);
+              getDhcpInfoForAdapter(table->indexes[ndx], ptr);
               if (winsEnabled) {
                 ptr->HaveWins = TRUE;
                 memcpy(ptr->PrimaryWinsServer.IpAddress.String,