QDnsLookup/Windows: use DnsQueryEx so IPv6 servers are supported

Similar test with link-local server on the same network:

$ $objdir/tests/manual/qdnslookup/qdnslookup.exe @fe80::1e1b:dff:fee2:49e6%Ethernet
; <<>> QDnsLookup 6.6.0 <<>> qdnslookup @fe80::1e1b:dff:fee2:49e6%Ethernet
;; status: NoError
;; QUESTION:
;qt-project.org                 IN A

;; ANSWER:
qt-project.org            3532  IN A    52.18.144.254

;; Query time: 17 ms
;; SERVER: fe80::1e1b:dff:fee2:49e6%Ethernet#53

Server's dnsmasq log shows it was queried.

We don't know why we must set the port to 0. It works for me the regular
way, but not for everyone who tested this patch.

[ChangeLog][QtNetwork][QDnsLookup] setNameserver() now supports IPv6
servers with on Apple systems, AIX, FreeBSD, NetBSD, Solaris, and
Windows.

(AIX, NetBSD and Solaris not directly tested, but their docs online show
they have res_setservers())

Change-Id: I3e3bfef633af4130a03afffd175d5bfd4e7922b9
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

1 files changed, 60 insertions, 19 deletions

diff --git a/src/network/kernel/qdnslookup_win.cpp b/src/network/kernel/qdnslookup_win.cpp
index 796ff9c206..7a09035774 100644
--- a/src/network/kernel/qdnslookup_win.cpp
+++ b/src/network/kernel/qdnslookup_win.cpp
@@ -5,37 +5,78 @@
 #include "qdnslookup_p.h"
 
 #include <qurl.h>
+#include <private/qnativesocketengine_p.h>
 #include <private/qsystemerror_p.h>
 
 #include <qt_windows.h>
 #include <windns.h>
 #include <memory.h>
 
+#ifndef DNS_ADDR_MAX_SOCKADDR_LENGTH
+// MinGW headers are missing almost all of this
+typedef struct Qt_DnsAddr {
+  CHAR  MaxSa[32];
+  DWORD DnsAddrUserDword[8];
+} DNS_ADDR, *PDNS_ADDR;
+typedef struct Qt_DnsAddrArray {
+  DWORD    MaxCount;
+  DWORD    AddrCount;
+  DWORD    Tag;
+  WORD     Family;
+  WORD     WordReserved;
+  DWORD    Flags;
+  DWORD    MatchFlag;
+  DWORD    Reserved1;
+  DWORD    Reserved2;
+  DNS_ADDR AddrArray[];
+} DNS_ADDR_ARRAY, *PDNS_ADDR_ARRAY;
+typedef struct Qt_DNS_QUERY_REQUEST {
+  ULONG                         Version;
+  PCWSTR                        QueryName;
+  WORD                          QueryType;
+  ULONG64                       QueryOptions;
+  PDNS_ADDR_ARRAY               pDnsServerList;
+  ULONG                         InterfaceIndex;
+  PDNS_QUERY_COMPLETION_ROUTINE pQueryCompletionCallback;
+  PVOID                         pQueryContext;
+} DNS_QUERY_REQUEST, *PDNS_QUERY_REQUEST;
+
+typedef void *PDNS_QUERY_CANCEL;    // not really, but we don't need it
+extern "C" {
+DNS_STATUS WINAPI DnsQueryEx(PDNS_QUERY_REQUEST pQueryRequest,
+        PDNS_QUERY_RESULT   pQueryResults,
+        PDNS_QUERY_CANCEL   pCancelHandle);
+}
+#endif
+
 QT_BEGIN_NAMESPACE
 
 void QDnsLookupRunnable::query(const int requestType, const QByteArray &requestName, const QHostAddress &nameserver, QDnsLookupReply *reply)
 {
     // Perform DNS query.
-    PDNS_RECORD dns_records = 0;
     const QString requestNameUtf16 = QString::fromUtf8(requestName.data(), requestName.size());
-    IP4_ARRAY srvList;
-    memset(&srvList, 0, sizeof(IP4_ARRAY));
+    alignas(DNS_ADDR_ARRAY) uchar dnsAddresses[sizeof(DNS_ADDR_ARRAY) + sizeof(DNS_ADDR)];
+    DNS_QUERY_REQUEST request = {};
+    request.Version = 1;
+    request.QueryName = reinterpret_cast<const wchar_t *>(requestNameUtf16.constData());
+    request.QueryType = requestType;
+    request.QueryOptions = DNS_QUERY_STANDARD;
+
     if (!nameserver.isNull()) {
-        if (nameserver.protocol() == QAbstractSocket::IPv4Protocol) {
-            // The below code is referenced from: http://support.microsoft.com/kb/831226
-            srvList.AddrCount = 1;
-            srvList.AddrArray[0] = htonl(nameserver.toIPv4Address());
-        } else if (nameserver.protocol() == QAbstractSocket::IPv6Protocol) {
-            // For supoprting IPv6 nameserver addresses, we'll need to switch
-            // from DnsQuey() to DnsQueryEx() as it supports passing an IPv6
-            // address in the nameserver list
-            qWarning("%s", QDnsLookupPrivate::msgNoIpV6NameServerAdresses);
-            reply->error = QDnsLookup::ResolverError;
-            reply->errorString = tr(QDnsLookupPrivate::msgNoIpV6NameServerAdresses);
-            return;
-        }
+        memset(dnsAddresses, 0, sizeof(dnsAddresses));
+        request.pDnsServerList = new (dnsAddresses) DNS_ADDR_ARRAY;
+        auto addr = new (request.pDnsServerList->AddrArray) DNS_ADDR[1];
+        auto sa = new (addr[0].MaxSa) sockaddr;
+        request.pDnsServerList->MaxCount = sizeof(dnsAddresses);
+        request.pDnsServerList->AddrCount = 1;
+        // ### setting port 53 seems to cause some systems to fail
+        setSockaddr(sa, nameserver, 0);
+        request.pDnsServerList->Family = sa->sa_family;
     }
-    const DNS_STATUS status = DnsQuery_W(reinterpret_cast<const wchar_t*>(requestNameUtf16.utf16()), requestType, DNS_QUERY_STANDARD, &srvList, &dns_records, NULL);
+
+    DNS_QUERY_RESULT results = {};
+    results.Version = 1;
+    const DNS_STATUS status = DnsQueryEx(&request, &results, nullptr);
     switch (status) {
     case ERROR_SUCCESS:
         break;
@@ -63,7 +104,7 @@ void QDnsLookupRunnable::query(const int requestType, const QByteArray &requestN
     }
 
     // Extract results.
-    for (PDNS_RECORD ptr = dns_records; ptr != NULL; ptr = ptr->pNext) {
+    for (PDNS_RECORD ptr = results.pQueryRecords; ptr != NULL; ptr = ptr->pNext) {
         const QString name = QUrl::fromAce( QString::fromWCharArray( ptr->pName ).toLatin1() );
         if (ptr->wType == QDnsLookup::A) {
             QDnsHostAddressRecord record;
@@ -125,7 +166,7 @@ void QDnsLookupRunnable::query(const int requestType, const QByteArray &requestN
         }
     }
 
-    DnsRecordListFree(dns_records, DnsFreeRecordList);
+    DnsRecordListFree(results.pQueryRecords, DnsFreeRecordList);
 }
 
 QT_END_NAMESPACE