[reactos] 01/01: [DNSRSLVR] R_ResolverFlushCache should only flush cached records which were not read from the hosts file

[Eric Kohl]

https://git.reactos.org/?p=reactos.git;a=commitdiff;h=17f932d78e98f2686cc61a...

commit 17f932d78e98f2686cc61acdf200f48d03f7edf9
Author:     Eric Kohl [e-mail]
AuthorDate: Mon Jan 6 00:45:41 2020 +0100
Commit:     Eric Kohl [e-mail]
CommitDate: Mon Jan 6 00:46:37 2020 +0100

[DNSRSLVR] R_ResolverFlushCache should only flush cached records which were not read from the hosts file
---
 base/services/dnsrslvr/cache.c     | 29 ++++++++++++++++++++---------
 base/services/dnsrslvr/hostsfile.c | 12 ++++++------
 base/services/dnsrslvr/precomp.h   | 20 +++++++++++++++++---
 base/services/dnsrslvr/rpcserver.c |  9 ++++-----
 4 files changed, 47 insertions(+), 23 deletions(-)

diff --git a/base/services/dnsrslvr/cache.c b/base/services/dnsrslvr/cache.c
index af4cc2a8597..e61cc8695a7 100644
--- a/base/services/dnsrslvr/cache.c
+++ b/base/services/dnsrslvr/cache.c
@@ -44,7 +44,7 @@ DnsIntCacheFree(VOID)
     if (!DnsCache.RecordList.Flink)
         return;

-    DnsIntCacheFlush();
+    DnsIntCacheFlush(CACHE_FLUSH_ALL);

DeleteCriticalSection(&DnsCache.Lock);
     DnsCacheInitialized = FALSE;
@@ -65,13 +65,14 @@ DnsIntCacheRemoveEntryItem(PRESOLVER_CACHE_ENTRY CacheEntry)
     HeapFree(GetProcessHeap(), 0, CacheEntry);
 }

-VOID
-DnsIntCacheFlush(VOID)
+DNS_STATUS
+DnsIntCacheFlush(
+    _In_ ULONG ulFlags)
 {
-    PLIST_ENTRY Entry;
+    PLIST_ENTRY Entry, NextEntry;
     PRESOLVER_CACHE_ENTRY CacheEntry;

-    DPRINT("DnsIntCacheFlush()\n");
+    DPRINT("DnsIntCacheFlush(%lu)\n", ulFlags);

/* Lock the cache */
     DnsCacheLock();
@@ -80,18 +81,24 @@ DnsIntCacheFlush(VOID)
     Entry = DnsCache.RecordList.Flink;
     while (Entry != &DnsCache.RecordList)
     {
+        NextEntry = Entry->Flink;
+
         /* Get this entry */
         CacheEntry = CONTAINING_RECORD(Entry, RESOLVER_CACHE_ENTRY, CacheLink);

/* Remove it from list */
-        DnsIntCacheRemoveEntryItem(CacheEntry);
+        if (((ulFlags & CACHE_FLUSH_HOSTS_FILE_ENTRIES) && (CacheEntry->bHostsFileEntry != FALSE)) ||
+            ((ulFlags & CACHE_FLUSH_NON_HOSTS_FILE_ENTRIES) && (CacheEntry->bHostsFileEntry == FALSE)))
+            DnsIntCacheRemoveEntryItem(CacheEntry);

/* Move to the next entry */
-        Entry = DnsCache.RecordList.Flink;
+        Entry = NextEntry;
     }

/* Unlock the cache */
     DnsCacheUnlock();
+
+    return ERROR_SUCCESS;
 }

DNS_STATUS
@@ -178,11 +185,14 @@ DnsIntCacheRemoveEntryByName(LPCWSTR Name)
 }

VOID
-DnsIntCacheAddEntry(PDNS_RECORDW Record)
+DnsIntCacheAddEntry(
+    _In_ PDNS_RECORDW Record,
+    _In_ BOOL bHostsFileEntry)
 {
     PRESOLVER_CACHE_ENTRY Entry;

-    DPRINT("DnsIntCacheAddEntry(%p)\n", Record);
+    DPRINT("DnsIntCacheAddEntry(%p %u)\n",
+           Record, bHostsFileEntry);

DPRINT("Name: %S\n", Record->pName);
     DPRINT("TTL: %lu\n", Record->dwTtl);
@@ -195,6 +205,7 @@ DnsIntCacheAddEntry(PDNS_RECORDW Record)
     if (!Entry)
         return;

+    Entry->bHostsFileEntry = bHostsFileEntry;
     Entry->Record = DnsRecordSetCopyEx(Record, DnsCharSetUnicode, DnsCharSetUnicode);

/* Insert it to our List */
diff --git a/base/services/dnsrslvr/hostsfile.c b/base/services/dnsrslvr/hostsfile.c
index 1c80dc0cffb..62554b91aa2 100644
--- a/base/services/dnsrslvr/hostsfile.c
+++ b/base/services/dnsrslvr/hostsfile.c
@@ -113,7 +113,7 @@ AddIpv4HostEntries(

/* Prepare the PTR record */
     swprintf(szReverseName,
-             L"%u.%u.%u.%u.in-addr.arpa",
+             L"%u.%u.%u.%u.in-addr.arpa.",
              pAddress->S_un.S_un_b.s_b4,
              pAddress->S_un.S_un_b.s_b3,
              pAddress->S_un.S_un_b.s_b2,
@@ -130,8 +130,8 @@ AddIpv4HostEntries(

PtrRecord.Data.PTR.pNameHost = pszHostName;

-    DnsIntCacheAddEntry(&ARecord);
-    DnsIntCacheAddEntry(&PtrRecord);
+    DnsIntCacheAddEntry(&ARecord, TRUE);
+    DnsIntCacheAddEntry(&PtrRecord, TRUE);
 }

@@ -171,7 +171,7 @@ AddIpv6HostEntries(
         szReverseName[j + 2] = szHexChar[(pAddress->u.Byte[k] >> 4) & 0xF];
         szReverseName[j + 3] = L'.';
     }
-    wcscat(szReverseName, L"ip6.arpa");
+    wcscat(szReverseName, L"ip6.arpa.");

ZeroMemory(&PtrRecord, sizeof(DNS_RECORDW));

@@ -184,8 +184,8 @@ AddIpv6HostEntries(

PtrRecord.Data.PTR.pNameHost = pszHostName;

-    DnsIntCacheAddEntry(&AAAARecord);
-    DnsIntCacheAddEntry(&PtrRecord);
+    DnsIntCacheAddEntry(&AAAARecord, TRUE);
+    DnsIntCacheAddEntry(&PtrRecord, TRUE);
 }

diff --git a/base/services/dnsrslvr/precomp.h b/base/services/dnsrslvr/precomp.h
index 81189cda9e6..2b7e5f35dd6 100644
--- a/base/services/dnsrslvr/precomp.h
+++ b/base/services/dnsrslvr/precomp.h
@@ -27,6 +27,7 @@
 typedef struct _RESOLVER_CACHE_ENTRY
 {
     LIST_ENTRY CacheLink;
+    BOOL bHostsFileEntry;
     PDNS_RECORDW Record;
 } RESOLVER_CACHE_ENTRY, *PRESOLVER_CACHE_ENTRY;

@@ -42,7 +43,14 @@ typedef struct _RESOLVER_CACHE
 VOID DnsIntCacheInitialize(VOID);
 VOID DnsIntCacheRemoveEntryItem(PRESOLVER_CACHE_ENTRY CacheEntry);
 VOID DnsIntCacheFree(VOID);
-VOID DnsIntCacheFlush(VOID);
+
+#define CACHE_FLUSH_HOSTS_FILE_ENTRIES     0x00000001
+#define CACHE_FLUSH_NON_HOSTS_FILE_ENTRIES 0x00000002
+#define CACHE_FLUSH_ALL                    0x00000003
+
+DNS_STATUS
+DnsIntCacheFlush(
+    _In_ ULONG ulFlags);

DNS_STATUS
 DnsIntCacheGetEntryByName(
@@ -51,8 +59,14 @@ DnsIntCacheGetEntryByName(
     DWORD dwFlags,
     PDNS_RECORDW *Record);

-VOID DnsIntCacheAddEntry(PDNS_RECORDW Record);
-BOOL DnsIntCacheRemoveEntryByName(LPCWSTR Name);
+VOID
+DnsIntCacheAddEntry(
+    _In_ PDNS_RECORDW Record,
+    _In_ BOOL bHostsFileEntry);
+
+BOOL
+DnsIntCacheRemoveEntryByName(
+    _In_ LPCWSTR Name);

DNS_STATUS
 DnsIntCacheGetEntries(
diff --git a/base/services/dnsrslvr/rpcserver.c b/base/services/dnsrslvr/rpcserver.c
index f79850ddb06..59e91cb4791 100644
--- a/base/services/dnsrslvr/rpcserver.c
+++ b/base/services/dnsrslvr/rpcserver.c
@@ -62,11 +62,10 @@ __stdcall
 R_ResolverFlushCache(
     _In_ DNSRSLVR_HANDLE pwszServerName)
 {
-    DPRINT("R_ResolverFlushCache()\n");
+    DPRINT("R_ResolverFlushCache(%S)\n",
+           pwszServerName);

-    // FIXME Should store (and flush) entries by server handle
-    DnsIntCacheFlush();
-    return ERROR_SUCCESS;
+    return DnsIntCacheFlush(CACHE_FLUSH_NON_HOSTS_FILE_ENTRIES);
 }

@@ -126,7 +125,7 @@ R_ResolverQuery(
             if (Status == ERROR_SUCCESS)
             {
                 DPRINT("DNS query successful!\n");
-                DnsIntCacheAddEntry(*ppResultRecords);
+                DnsIntCacheAddEntry(*ppResultRecords, FALSE);
             }
         }
     }