netwerk/dns/PlatformDNSWin.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* vim:set ts=4 sw=2 sts=2 et cin: */
   3 /* This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "GetAddrInfo.h"
   8 #include "mozilla/net/DNSPacket.h"
   9 #include "nsIDNSService.h"
  10 #include "mozilla/Maybe.h"
  11 #include "mozilla/ScopeExit.h"
  12
  13 #ifdef DNSQUERY_AVAILABLE
  14 // There is a bug in windns.h where the type of parameter ppQueryResultsSet for
  15 // DnsQuery_A is dependent on UNICODE being set. It should *always* be
  16 // PDNS_RECORDA, but if UNICODE is set it is PDNS_RECORDW. To get around this
  17 // we make sure that UNICODE is unset.
  18 #  undef UNICODE
  19 #  include <ws2tcpip.h>
  20 #  undef GetAddrInfo
  21 #  include <windns.h>
  22 #endif  // DNSQUERY_AVAILABLE
  23
  24 namespace mozilla::net {
  25
  26 #define LOG(msg, ...) \
  27   MOZ_LOG(gGetAddrInfoLog, LogLevel::Debug, ("[DNS]: " msg, ##__VA_ARGS__))
  28
  29 nsresult ResolveHTTPSRecordImpl(const nsACString& aHost, uint16_t aFlags,
  30                                 TypeRecordResultType& aResult, uint32_t& aTTL) {
  31   nsAutoCString host(aHost);
  32   PDNS_RECORD result = nullptr;
  33   nsAutoCString cname;
  34   aTTL = UINT32_MAX;
  35
  36   DNS_STATUS status =
  37       DnsQuery_A(host.get(), nsIDNSService::RESOLVE_TYPE_HTTPSSVC,
  38                  DNS_QUERY_STANDARD, nullptr, &result, nullptr);
  39   if (status != ERROR_SUCCESS) {
  40     LOG("DnsQuery_A failed with error: %ld\n", status);
  41     return NS_ERROR_UNKNOWN_HOST;
  42   }
  43
  44   // This will free the record if we exit early from this function.
  45   auto freeDnsRecord =
  46       MakeScopeExit([&]() { DnsRecordListFree(result, DnsFreeRecordList); });
  47
  48   auto CheckRecords = [&aResult, &cname, &aTTL](
  49                           PDNS_RECORD result,
  50                           const nsCString& aHost) -> nsresult {
  51     PDNS_RECORD current = result;
  52
  53     for (current = result; current; current = current->pNext) {
  54       if (strcmp(current->pName, aHost.get()) != 0) {
  55         continue;
  56       }
  57       if (current->wType == nsIDNSService::RESOLVE_TYPE_HTTPSSVC) {
  58         const unsigned char* ptr = (const unsigned char*)&(current->Data);
  59         struct SVCB parsed;
  60         nsresult rv = DNSPacket::ParseHTTPS(current->wDataLength, parsed, 0,
  61                                             ptr, current->wDataLength, aHost);
  62         if (NS_FAILED(rv)) {
  63           return rv;
  64         }
  65
  66         if (parsed.mSvcDomainName.IsEmpty() && parsed.mSvcFieldPriority == 0) {
  67           // For AliasMode SVCB RRs, a TargetName of "." indicates that the
  68           // service is not available or does not exist.
  69           continue;
  70         }
  71
  72         if (parsed.mSvcFieldPriority == 0) {
  73           // Alias form SvcDomainName must not have the "." value (empty)
  74           if (parsed.mSvcDomainName.IsEmpty()) {
  75             return NS_ERROR_UNEXPECTED;
  76           }
  77           cname = parsed.mSvcDomainName;
  78           ToLowerCase(cname);
  79           break;
  80         }
  81
  82         if (!aResult.is<TypeRecordHTTPSSVC>()) {
  83           aResult = mozilla::AsVariant(CopyableTArray<SVCB>());
  84         }
  85         auto& results = aResult.as<TypeRecordHTTPSSVC>();
  86         results.AppendElement(parsed);
  87         aTTL = std::min<uint32_t>(aTTL, current->dwTtl);
  88       } else if (current->wType == DNS_TYPE_CNAME) {
  89         cname = current->Data.Cname.pNameHost;
  90         ToLowerCase(cname);
  91         aTTL = std::min<uint32_t>(aTTL, current->dwTtl);
  92         break;
  93       }
  94     }
  95     return NS_OK;
  96   };
  97
  98   int32_t loopCount = 64;
  99   while (loopCount > 0 && aResult.is<Nothing>()) {
 100     loopCount--;
 101
 102     nsresult rv = CheckRecords(result, host);
 103     if (NS_FAILED(rv)) {
 104       return rv;
 105     }
 106
 107     if (aResult.is<Nothing>() && !cname.IsEmpty()) {
 108       host = cname;
 109       cname.Truncate();
 110       continue;
 111     }
 112
 113     if (aResult.is<Nothing>()) {
 114       return NS_ERROR_UNKNOWN_HOST;
 115     }
 116   }
 117
 118   // CNAME loop
 119   if (loopCount == 0) {
 120     return NS_ERROR_UNKNOWN_HOST;
 121   }
 122
 123   if (aResult.is<Nothing>()) {
 124     // The call succeeded, but no HTTPS records were found.
 125     return NS_ERROR_UNKNOWN_HOST;
 126   }
 127
 128   if (aTTL == UINT32_MAX) {
 129     aTTL = 60;  // Defaults to 60 seconds
 130   }
 131   return NS_OK;
 132 }
 133
 134 }  // namespace mozilla::net